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                           A

                  DICTIONARY

                           OF

          CHEMISTRY,

                          ON THE
               BASIS OF MR. NICHOLSON'S;
                         IN WHICH
   THE PRINCIPLES OF THE SCIENCE ARE INVESTIGATED ANEW,
AND ITS APPLICATIONS TO THE PHENOMENA OF NATURE, MEDICINE,
       MINERALOGY, AGRICULTURE, AND MANUFACTURES,
                        DETALLED.
            BY  ANDREW URE, M. D.

PROFESSOR OF THE ANDERSOIUAN nrSTITUTIOIT, MEMBER OF THE GEOLOGICAL SOCIETY,
                          &C &C.
                      WITH AN
           antrotmctorp  ^tggertatfon;
                     CONTAINING
INSTRUCTIONS FOR CONTERTING THE ALPHABETICAL ARRANGEMENT
           INTO A SYSTEMATIC ORDER OF STUDY.
              FIRST AMERICAN EDITION;
    WITH SOME ADDITIONS, NOTES, AND CORRECTIONS,
              BY ROBERT  HARE, M. D.
      PROFESSOR OF CHEMISTRY IN THE UNIVERSITY OF PEXNSYLVANIA.
                     ASSISTED BY
              FRANKLIN BACHE, M. D.
MEMBER OP THE AMERICAS PHILOSOPHICAL SOCIETY ANL OF THE ACADEMY OF NATURAL
                  SCIENCES OF PHILADELPHIA,
                     vol.  n.

                 PHILADELPHIA:
PUBLISHED BY ROBERT DESDLVER, No. 110, WALNUT STREET.
                        1821. 
Eastern District of Pennsylvania, to wit:
       BE IT REMEMBERED, That on the thirteenth day of October, in the forty-sixfli
 year of the independence of the United States of America, A. D. 1821, Robert Desil-
 ver,  of the said district, hath deposited in this office the title of a book, the  right
 whereof he claims as proprietor, in the words following, to wit:

       " A Dictionary of Chemistry on the basis of Mr. Nicholson's;  in which the prin-
   " ciples of the Science are investigated anew, and its applications to  the  phenomena
   *• of Nature, Medicine, Mineralogy,  Agriculture,  and Manufactures, detailed.  By An-
   " drew  Ure, M. D.  Professor of the Andersonian Institution,  Member of the Geologi-
   " cal Society, &c. &c.  with an Introductory Dissertation;  containing instructions for
   " converting the Alphabetical Arrangement  into a systematic order of study.  First
   " American edition; with some additions, notes, and corrections, by  Robert Hare, M.
   " D.  Professor of Chemistry in the University of Pennsylvania: Assisted by Frankliu
   " Bache, M. D. Member of the American Philosophical Society, and of the Academy of
   " Natural Sciences of Philadelphia.   Vol. II.

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 prints."                                                D.  CALDWELL,
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  Paper, manufactured by  £
foshuaand Thomas Gilpin. >
'> 
r

tow H+.   ^ 5 DICTIONARY



                    CHEMISTRY
5  ^'fi  £-&-  j/**&4<*t  f^
                 EAR

     EAGLE-STONE.  A clay ironstone.
       * EARTHS.  Fifteen years ago, few
 •substances seemed more  likely to retain
 a  permanent  place in chemical arrange-
 ments, than the solid and refractory earths,
 which compose the  crust  of the globe.
 Analysis had shown, that the various stony
 or  pulverulent masses, which  form  our
 mountains, valleys, and plains, might  be
 considered as resulting from the combina-
 tion or intermixture,  in various numbers
 and proportions, of nine primitive earths,
 to which the following names were given:
   1. Barytes.  2.  Strontites.  3. Lime.  4.
 Magnesia.  5.  Alumina, or clay.  6. Silica.
 7.  Glucina.  8. Zirconia.  9. Yttria.
   Alkalis, acids,  metallic ores, and native
 metals, were supposed to be of an entirely
 dissimilar  constitution.
   The brilliant discovery by Sir H. Davy
 in  1808, of the metallic bases of potash,
 soda, barytes, strontites, and lime, subvert-
 ed the ancient ideas regarding the earths,
 and taught us to regard them as all belong-
 ing, by most probable analogies, to the me-
 tallic  class.  According to an  ingenious
 suggestion of Mr.  Smithson, silica, howev-
 er, ought to be ranked with acids, since it
 has the power in native mineral compounds
 of neutralizing the alkaline earths, as well
 as  the common  metallic oxides.  But as
 this property is also possessed  by many
 metallic  oxides, it  can afford no evidence
 against the metallic nature  of the siliceous
 basis.   Alumina, by the experiments of
 Ehrman, may be made to saturate  lime,
 producing  a glass; and the triple com-
 pounds of magnesia, alumina, and lime, are
 perfectly neutral, in porcelain.  We might
 therefore refer alumina as well as silica, to
 the same class with the oxides of antimony,
 arsenic, chromium, columbium,  molybde-
num, titanium,  and tungsten.  Alumina,
however, bears to silica, the same relation
that oxide of antimony does to that of arse-
                  EGE

  nic j the antecedent pair acting the part of
  bases, while the consequent pair act only
  as acids.  The compound or  the  fluoric
  principle  with silica is of too mysterious  a
  nature to be employed  in this discussion.
  The almost universal function which silica
  enjoys of saturating the  alkaline  oxides in
  the native earthy minerals, is exhibited, in
  a very striking manner, in Mr. Allan's val-
  uable Synoptic Tables. From his fifth to
  his  fifteenth table of analyses, the column
  of silica is always complete, whatever de-
  ficiency or variation may occur  in the co-
  lumns of the earthy bases.  At leasi, only a
  very few exceptions need be made for the
  oriental gems, which consist of strongly ag-
  gregated alumina.
   To the above  nine  earthy substances',
  Berzelius has lately added a tenth which
  he calls thorina.* \ See soil and analysis of
 soils. \
   Earthenware.   See Pottery.
   Eao db Luce, consists  chiefly of the es-
 sential oil of amber and the volatile alkali.
   Echini.  Calcareous petrifactions of the
 echinus, or sea hedgehog.
   Effervescence  is the commotion pro-
 duced in fluids by  some part of the mass
 suddenly taking the elastic form, and es-
 caping in numerous bubbles.
   Efflorescence is the effect which takes
 place  when bodies spontaneously become
 converted into a dry powder. It is almost
 always occasioned by the loss of the water
 of crystallization in saline bodies.
  * Egkran.   A sub-species of pyramidal
 garnet.  Colour reddish-brown.  Massive,
 sometimes  crystallized in rectangular four-
 sided prisms, with  cylindrical convex late-
 ral planes.  The prisms are long, and deep-
 ly longitudinally streaked.  Shining, vitre-
 ous.  Cleavage, twofold. Fracture, uneven.
 Feebly translucent on the edges.  Scratch-
 es feldspar. Brittle. Sp.gr. 3.294. It melts
into a black scoria.  It occurs in a bed of 
ELA
ELE
 feldspar and hornblende, at Haslau, near
 Eger in Bohemia.*
   Erg9.  The eggs of hens, and of birds
 in general, are composed of several dis-
 tinct substances.   1. The shell, or exter-
 nal  coating, which is composed of carbo-
 nate of lime .72, phosphate of lime  .2, ge-
 latin .3.  The remaining  .23 are perhaps
 water.  2. A thin  white and  strong mem-
 brane, possessing  the usual  characters  of
 animal  substances.  3.  The  white  of the
 egg, for  which see Albume  .   4. The
 yolk, which appears to consist of  an oil  of
 the nature of fat oils, united with a portion
 of serous  matter,  sufficient  to render it
 diffusible in cold water, in the  form of an
 emulsion, and concrescible by heat.  Yolk
 of egg is used as the medium  for render-
 ing resins and oils diffusible in water.
  * Eisenrahm.  Red and brown; the scaly
 iron ore, and scaly  manganese ore.*
  *  Elain.  The  oily  principle  of solid
 fats, so named by its discoverer, M. Chev-
 reul. Chevreul dissolves the tallow in very
 pure hot alcohol, separates the  stearin by
 crystallization, and then procures the eldin,
 by evaporation of the spirit.  But M. Bra-
 connot  has adopted the simpler and pro-
 bably a more exact method.  By squeez-
 ing  tallow between the  folds of  porous
 paper, the  eldin  soaks into it, while the
 stearin  remains.   The paper being then
 soaked in water, and pressed, yields up its
 oily  impregna.ion.  Elain has  very much
 the nppearance and properties  of vegeta-
ble oil.  It is liquid at the temperature  of
 60*. Its smell and colour are  derived from
 the solid fats from which it is extracted.
  Hitman  eldin is  yellow, without  odour.
 Specific gravity 0.913.
  Eldin of sheep; colourless, a  faint smell.
 Sp. gr. 0.915.
  Elain of ox ; colourless, and almost with-
out odour.   Sp. grav. 0.915.
  Elain of hog ,■ do. do.  0.915.
  Eldin of jaguar ; lemon colour,  odorous.
0.914.
  Eldin of goose ; light lemon colour, little
 odour.   0.929.
  Solubility in alcohol ofsp. gr. 0.7952.
  Human eldin; 11.1 gr. by  9  gr.  at the
boiling point.
  Eldin of sheep; 3.79 gr. by 3 gr. at do.
  Eldin of ox,- 5.8 gr. by 4.7 gr. at do.
  Eldin of hog ,■ 11.1 gr. by 9.0  gr. at do.
  Eldin of jaguar,- 3.35 gr. by 2.71 gr.  at
do.
  Eldin of goose;  11.1 gr. by 9.0 gr. at do.
  Elain of the fat  of ox, extracted by al-
 cohol, yields, by the action of potash.

      Of saponified fat,         92.6 parts
      Of soluble matter,        7.4

  Those of the oilier fats yield,
      Of saponified fat,         89
      Of soluble matter,        11
  In M. Chevreul's 7th  memoir on  fats,
published in the  7th  vol of the Ann. dc
Chimie et Phys., he gives the following as
the composition  of the oleates from sper-
maceti :—

       Oleic acid    -    100
      Barytes       -      31.24
      Strontian     -      23.18
      Oxide of lead      100.00


  If we suppose the last a suboleate, the
equivalent of this oleic acid will  be 28.
The oil or oleic acid of the delphinus glo-
biceps is remarkably soluble  in cold  alco-
hol ; 100 parts of which of sp gr. 0.795, at
68°, dissolve 123 of the oil.  When that
oil  is freed by cold from  a crystallizable
matter,  100 parts of alcohol, sp. gr. 0.820,
dissolve  149.4  of oil at the atmospheric
temperature.  It was slightly acid  by the
test of  litmus,  which he ascribes  to the
presence of an aqueous fluid.   See Fat.*
  * Elaot.it>:.   A   sub-species of pyra-
midal feldspar.   Colours, duck-brown,  in-
clining to green, and flesh-red, inclining to
gray or brown.   Massive, and in granular
concretions.  Lustre shining and resinous.
Fracture  imperfect  conchoidal.   Faintly
translucent.  Hardness as feldspar.  Easily
frangible.  Sp.  gr. 2.6.  Its  powder forms
a jelly with acids.  Before the  blow-pipe,
it melts into a milk-white enamel. Its con-
stituents are 46.5 silica, 30.25 alumina, 0.75
lime,  18 potash, 1 oxide of iron, and 2 wa-
ter.  Klaproth.  The blue is found at Laur-
wig, and the red at Stavern and Friedricks-
warn, both in the rock named zircon  syenite.
The pale blue has an opalescence, like the
cat's eye, which occasions it to  be cut into
small  ornaments.   It  is called fettstein  by
Werner, from its resinous nature. Jameson.*
  * Elecampane.   SeelNULix*
  * Electricity.   The phenomena  dis-
played by rubbing a piece  of amber, con-
stitute the first physical fact recorded in
the history of science.   Thales of Miletus,
founder  of the Ionic  school, ascribed its
mysterious power  of  attracting and  re-
pelling light  bodies to an inherent  soul or
essence, which, awakened by friction, went
forth and brought back  the small particles
floating around.  In  times  near   to  our
own, the same hypothesis was resorted to,
by the  honourable  Robert Boyle.   From
electron, the Greek  name  of amber, has
arisen the science of electricity,  which  in-
vestigates the  attractions and  repulsions,
the emission of light, and explosions, which
are produced, not only by the friction of
vitreous, resinous, and  metallic  surfaces,
but by the heating, cooling, evaporation,
and mutual contact, of a vast number of
bodies: 
ELE
ELE
   1.  General statement of electrical pheno-
 mena.
   If  we rub, with  a dry hand or a  silk
 handkerchief, a glass tube, and then  ap-
 proach it  to bits of paper or  cotton, to
 feathers,  or which is better,  gold leaf, it
 will first attract these bodies, and then re-
 pel them.   If the  tube be held  parallel
 to a table  on which they have  been laid,
 an electrical dance will be performed. If
 to the farther end of the tube we hang a
 brass ball, by a thread of linen, hemp,  or a
 metallic wire, the ball will participate with
 the rubbed tube, in its mysterious powers.
 But if the ball be suspended  by a cord of
 silk, worsted, or hair, or by a rod of glass,
 wax or pitch, the attractive and repulsive.'
 virtue will not pass into it.
   When the atmosphere is dry, if we take
 in one hand a rod of glass, and in the other
 a  stick of sealing  wax, and after having
 rubbed them against silk or  worsted, ap-
 proach one of them to a bit of gold  leaf
 floating in the air, it will first attract  and
 then  repel it.  While the film  of gold is
 seen to avoid the contact of the rod which
 it has touched, if we bring the other rod
 into its neighbourhood, attraction will im-
 mediately ensue; and this alternate attrac-
 tion and repulsion may be strikingly  dis-
 played by placing the two excited rods at
 a small distance asunder, with the gold
 leaf between.
   If  we suspend close together, by  silk
 threads, two cylinders of rush-pith,  and
 touch their lower ends with either the rub-
 bed wax or glass, the pieces of pith  will
 instantly recede from each other at a con-
 siderable  angle.  If  we now merely  ap-
 proach to the bottom of the diverging cy-
 linders, the rod with which they had been
 touched, their divergence  will increase;
 but if we approach the other  rod, they
 will instantly collapse through their whole
 extent.   When the rods are rubbed in  the
 dark, a lambent light  seems diffused over
 them, and a pungent spark will pass into a
 knuckle brought near them.  If the per-
 son who makes these experiments happens
 to stand on a cake of wax, or a stool with
 glass  feet, then on rubbing the glass tube,
 he  will acquire the above attractive  and
 repulsive powers; but the light  bodies re-
 pelled by the tube, will be attracted by his
 body, and vice versa.  Hence  we see, that
the rubbing body acquires electrical pro-
 perties, dissimilar to those acquired by the
 substances rubbed.
  Such is a sketch of the  elementary phe-
 nomena of electricity.  The science, in its
 modern augmentation, seems to compre-
 hend  almost every change of  the  corpus-
 cular  world, however minute and myste-
rious, as well as  the long recognized and
magnificent meteors  of the  atmosphere.
Let us now take a methodical view of them,
its far as the limits of our work will permit.
We  shall consider electrical phenomena
under four heads:—
   1st, Of the- Excitement of Electricity,
or the various means by which the electri-
cal equilibrium is disturbed.
   2d, Of the Two Electricities.
   3d, Of  the Distribution of  Electri-
city.
   4th, Of the Voltaic Battery and its Ef-
fects:  calorific, or  igniting;  and decom-
posing,  or the chemical agencies  of elec-
tricity.
   Concerning the nature of the  electrical*,
essence, we are equally in the  dark as con-
cerning the  nature of caloric.  The phe-
nomena may be referred  in  both cases,
either to a peculiar fluid, whose particles
are  endowed  with  innate idio-repulsive
powers, or  to  a peculiar affection of the
molecules of common matter.
   I.  Of Electrical Excitement.
   1. The  mutual friction of all solids, whe-
ther similar or dissimilar, and of many
fluids against solids, will invariably excite
electrical  phenomena, provided one of the
bodies be of such a nature  as to obstruct
the speedy  diffusion of the electrical vir-
tue.   Hence we must  commence  with a
list of electrical conductors and non-con-
ductors.
   1st, The  following substances conduct
or favour the rapid distribution of electri-
city.  Those at the  head of the list pos-
sess a conducting power greater than that
of water,  in the proportion of three  mil-
lions to  one.
 1. Copper          16. Saline solutions
 2. Silver           17.  Animal  fluids
 3. Gold            18.  Sea water
 4. Iron            19.  Water •—
 5. Tin            20. Ice and  snow
 6. Lead               above 0°
 7. Zinc           21. Living vegetables
 8. Platinum       22. Living animals
 9. Charcoal--     23. Flame
10. Plumbago..     24. Smoke
11. 6trong acids    25. Vapour
12. Soot and lamp-  26. Salts
   black —■        27. Rarefied air
13. Metallic ores   28.  Dry earths
14. Metallic oxides 29. Massive minerals
15. Dilute acids
  2d, The following is  a list of  electrical
non-conductors, in the order of their insu-
lating power:
 1. Shell-lac           trifled  bodies,
 2. /Vmber             comprehending
 3. Resins             diamond and
 4. Sulphur            crystallized trans-
 5. Wax               parent  minerals
 6. Asphaltum       8.  Raw silk
 7. Glass,  and all vi-  9.  Bleached silk 
ELE
ELE
 10. Dyed silk       19. Caoutchouc       of electricity, is probably very  different
 11. Wool, hair,  and 20. Lycopodium       from the chain ofnature.f
     feathers         21. Dry chalk and       There seems to be no physical quality
 12. Dry gases          lime              common to the conductors, or to the non-
 13. Dry paper, parch- 22. Phosphorus       conductors.   The crystalline arrangement
     ment, and       23. Ice below 0° of    always  introduces non-conducting  quali-
     leather             Fahr.             ties, more or less perfect, it we exclude the
 14. Baked wood, and 24. Oils, of which the  .metals.   Thus carbon, in the pulverulent
     dried vegetables    densest are best   or fibrous form, is an excellent conductor,
 15. Porcelain        25. Dry  metallic  ox-   but  crystallized in diamond, it becomes an
 16. Marble             ides,   including   insulator.  The same difference exists be-
 17- Massive minerals    fused    alkaline   tween water  and ice; and,  as is said, be-
     non-metallic         and  earthy  hy-   tween pounded  and compact  glass.   If
 18. Camphor            drates.            pounded glass be indeed  a conductor,  it
                                          must, from my experiments, be so in a very
   The general arrangement  of the above  ^ imperfect degree.  Glass, resins, and fats, -
 lists is tolerably correct, though it is pro-  - which in the solid state are non-conductors, i
 bable that phosphorus,  when  freed from  -become conductors on being melted.      '
 adhering moisture,   would stand  higher     On the evolution of electricity by friction,
 among insulators.                         js founded the construction of our common
   All material substances have been usually   electrical machines.  It was  supposed at
 divided into two classes; of electrics, and   one  time, that their action was  connected
 non-electrics.  Butthisdistinctionisground-   with the oxidizement of the  amalgam,
 less, and calculated to mislead. Every sub-   which is usually applied to the face of the
 stance is an electric, or capable by friction   rubber.   But  Sir H. Davy having mounted
 of exhibiting electrical phenomena.  Thus,   a small machine in a glass vessel, in such a
 if we take any of the bodies in the first list,   manner that it could be made to revolve in
 which are commonly called non-electrics,   any  species of gas, found that it was active
 for instance a  copper ball, and insulating it   in hydrogen,  and more active in carbonic
 by a rod of any convenient  solid in the se-   acid, than even in the atmosphere. Indeed
 cond list, if we rub the ball with a piece of   if we recollect that the friction of surfaces
 silk or worsted, we shall find it to become   of glass, silk, or sealing-wax, is  sufficient
 electrical.  It  will attract and  repel light   to produce electrical  appearances, we can-
 bodies,  and will give lucid sparks to a fin-   not suppose oxidizement of metal to be es-
 ger which approaches it.  To account for   sential to their production.  If we even
 these appearances, it has been said that the   impel a current of air, or a minute stream
 electrical equilibrium which constitutes the----------------------------------------
 common state of matter, is disturbed by the     j I have never yet met with difficulty in
 friction; and that one of the two bodies at-   explaining the phenomena of mechanical
tracts to itself a surcharge of the electrical   electricity upon Franklin's theory.  An ob-
 fluid, while the other remains in a deficient  jection to it, which operates perhaps more
 state, whence  the terms of positive and ne-   than any other, is  founded on erroneous
 gative,  or  plus  and  minus,  have  arisen,   premises.  I mean that, which is grounded
 Many of the appearances, however, are re-   on the well-known phenomena of the reces-
 conciled with difficulty to a mere excess or   sion  from each other, of light bodies, whe-
deficiency of one  fluid; and hence the hy-   ther electrified minus  or plus.   It  is al-
pothesis of a compound fluid, susceptible   leged, that the presence and absence of a
of  decomposition  by friction  and  other   principle cannot have the same effect; that,
means, has been introduced.   The result-   when bodies are surcharged with the elec-
ing fluids are  necessarily co-existent, the  trie fluid, it is easy to conceive,  that they
 one appearing on the body rubbed, and the  may  repel each other,  as  in the instance
 other on the rubber;  but since the one is  of the particles of solids by a union with
 most usually  evolved on  the  surface of  caloric; but it  is not probable, that a defi-
 lass, and the other  on that of resins, the  ciency of electricity will any more  cause
 rst has been called  the  vitreous,  and the  masses to separate, than that cold and heat
 second the resinous electricity.  These two  should both cause expansion in the same
 fluids, corresponding to the positive and ne- /solid.  The truth is, that repulsion  is not
gative of Franklin, by their  reunion pro- t the cause of the  separation of electrified !
duce a species of reciprocal neutralization, ^bodies, whether excited positively or nega- i
and electrical  repose.  Some recent inves-  tively. Their  recession is, in either case,
ligations, of that profound physico-geome-  the consequence of an attraction  between
 ter M. Poisson, render the second explana-  them and the surrounding medium.  And
tion the less improbable of the two.  Let  it is  of no importance, whether the compa-
us always bear in  mind, however, that the  rative  surcharge in them attract the mat-
hypothetical thread  which we employ at  ter in the medium around; or the compara-
present, to tie together the scattered facts  tive surcharge  in this, attract them. 
ELE
ELE
 of pure mercury, on a plate of dry glass,
 electrical excitement will result.
   The electrical phenomena excited by
 friction, are generally so energetic, as to
 require nothing but  bits of any light mat-
 ter for their exhibition.  When we have to
 detect the  disturbance of the electrical
 equilibrium, occasioned by  other and fee-
 bler causes, more refined electroscopic means
 are required.   The most delicate of simple
 electroscopes consist of two oblong narrow
v slips of gold leaf, suspended from the cen-
 tre of the brass cap of a glass cylinder,
 about 2 inches  diameter and 6 inches long.
 The  bottom of the cylinder should rest in
 a metallic sole;  from which, on the opposite
 sides,  two narrow slips  of tin-foil should
 raise up the inner surface of the glass, to
 the level of the middle of the pendent slips
 of gold leaf.    Coulomb's  electroscope,
 which acts by the torsion of a fibre of the
 silk worm, suspending in a glass case a ho-
 rizontal needle  of shell lac, terminated in
 a little disc of gilt paper, is still more sen-
 sible, and is much employed by the Pari-
 sian philosophers. Aided by either of these
 instruments, we can observe the excitement
 of electrical phenomena in the following
 cases, independent of friction.
   2. In the fusion of inflammable bodies.
 If we pour melted sulphur into an insulated
 metallic cup, we shall find after it concretes,
 that the sulphur and cup will be both elec-
 trified; the former with  the vitreous, the
 latter  with  the  resinous  electricity;  or
 sometimes  reversely   But Messrs.  Van
 Marum and Troostwyck, from a series of
 experiments which they made on a  number
 of bodies,  were  led to conclude that  the
 electricity was produced in such cases as
 the above,either by the friction from change
 of bulk, when the melted matter concretes,
 or from the friction which the electrical
 bodies undergo, when they spread upon the
 surfaces of other bodies, upon which they
 are poured in the liquid state.  When gla-
 cial phosphoric acid congeals, and when
 calomel concretes in sublimation, electrical
 phenomena  are produced.   The  experi-
ments of Henry on the electricity  excited
during the concretion of melted chocolate,
do not seem easily explicable on the prin
ciple of friction.  When it is c ioled in the
tin pans into which it is first received, the
electricity is strong, and continues for some
time after it is removed.  When it is again
melted and allowed to cool, the electrical
virtue is restored, but not  to  its  former
strength.  After the third or fourth fusion,
the electricity  becomes extremely weak.
When the chocolate is mixed with a little
olive oil before it is poured out of the pan,
it then becomes strongly electrical.  Now
in so far as friction is concerned, we should
have the electrical phenomena as decided
at the fourth fusion,  as the first; and the
 presence of oil ought to lessen the effect,
 as it diminishes the friction.  It is highly
 probable that the act of crystallization  al-
 ways  induces a change of the electrical
 equilibrium; as the crysUtt%e structure ]
 changes the electrical relations in general. '
   3. Electricity produced by evaporation.
   If on  the cap of the  gold leaf electros-
 cope we place a small  metallic cup, con-
staining a little water,  and drop  into it a
?'red-hot  cinder, the gold leaves  will  in-
 stantly diverge to a very considerable  an-
 gle.   Or if we insulate a hot crucible of
 iron, copper,  silver, or  porcelain, and pour
 into it a few  drops of water,  alcohol, or
 ether, on connecting the crucible  with  an
 electroscope,   electrical  phenomena will
 appear.
   4. Electricity produced by disengagement
 of gas.
   If into a platinum cup, resting on the  top
 of the electroscope, we put a little dilute
 sulphuric acid, and then  throw  in some
 iron filings, or chalk, the gold leaves will
 diverge, as the effervescence becomes  ac-
 tive.  The same thing  is producible with
 nitric  acid and copper filings.
   5. Electricity produced by disruption of
 a solid body.
   If we  suddenly  tear asunder plates of
 mica,  break across  a stick of sealing-wax,
 cleave up a piece of dry and warm wood,
 or scrape its  surface with  window glass,
 or finally cause a bit of unannealed glass,
 such as a Prince Rupert's drop, to fly asun-
 der by snapping off a  bit of its  tail,  the
 electrical equilibrium  will be  disturbed.
 Most of these cases may, however, be pro-
 bably  referred to friction among the mole-
 culae.  To the  same  head we may also refer
 the  electricity excited by sifting  various
 powders and metallic filings through a me-
 tallic sk-ve, or by dropping them  on insu-
 lated plates.
   6. Electricity excited by change of tem-
 perature.
   M Haiiy made the important discovery,
 that the property of exhibiting electrical
 phenomena by heat, belongs to those crys-
 tals only whose forms are not symmetrical;
 that is to say, of which one extremity  or
 side does not correspond with the opposite.
 Thus,  for example, the variety of  tourma-
 line which  he calls isogone,  a prismatic
 crystal of nine sides, terminated at one end
 with a three-sided,  and at the other with a
 six-sided pyramid,  when exposed to  the
 temperature of 108° Fahr. shows  no sign
 of electricity.  But if we plunge it for some
 minutes  into boiling water,  and taking it
 put with small forceps, by the middle  of
 the prism, present it to the cap of the elec-
 troscope, or to a pith  ball pendulum,  al-
 ready  charged with a  known  electricity,
 we shall find it will attract it with one  of
 its poles, and  repel with the other.  The 
ELE                                 ELE
three-sided pyramid possesses the resinous,
and the six-sided the vitreous electricity.
Although an elevation of temperature be»
necessary to dev^lope this property,  it is
not needed fy»- .s maintenance. It will con-
tinue electrical for six hours after its tem-
perature has fallen to the former point, es-
pecially if it be laid on an  insulating sup-
port.   In fact it loses its electricity, more
slowly than a piece of glass, in similar cir-
cumstances.
  This property of attracting light bodies
when heated, was  recognized  by the an-
cients in tourmaline, which was  probably
their  lyncurium.  The Dutch in Ceylon gave
it  the name of Aschentrikker, from its at-
tracting the  ashes, when a piece of it was
laid near the fire.  It appears that a  heat
above 212°, impairs its electrical  activity;
and that it is some time before it recovers
its pristine virtue.  When  the tourmaline
is large, it is capable of emitting flashes of
electrical light.  The Brazilian or Siberian
topaz  exhibits the  same  phenomena by
being slightly heated. The topazes of Sax-
ony, and the blue topaz of Aberdeenshire,
are electrical only  by  friction.   Boracite,
mesotype, and crystallized calamine, pos-
sess similar properties of becoming elec-
trical with heat.
  7.  Electricity produced  by contact of
dissimilar bodies. If we take two flat discs,
one of silver or copper, and another of
zinc,  each two or  three  inches diameter,
furnished with  glass handles,  and bring
them into momentary contact by their flat
surfaces, we shall find, on separating them,
that they are both electrified.   If we touch
a disc of sulphur gently heated, with the
insulated copper plate,  the  electrical  ef-
fects will be still more striking. Acid crys-
tals,  touched with  metallic plates, yield
electrical phenomena.  Finally, crystals of
oxalic acid, brought into contact with dry
quicklime,  develope  electricity.   On the
excitation of electricity by contact of dis-
similar chemical bodies, is founded the
principle of galvanic action, and the con-
struction of the voltaic  battery.   Of this
admirable  apparatus we shall treat in the
sequel.
  II.  Of the two Electricities.
  We have already stated, that the two elec-
tricities are always connate and simultane-
ous.  If they result from  the  decomposi-
tion of a quiescent neutral compound fluid,
we can easily see that this co-existence  is
inevitable.  Hence also we can  understand,
how any body by friction, may be made to
exhibit either of the two electricities, ac-
cording to the nature of the rubber.  The
only exception is the back of a living cat,
which gives vitreous electricity, with every
rubber hitherto tried.   To  know  the  spe-
cies of electricity evolved, it is merely ne-
cessary to communicate  beforehand, to the
Blips of gold leaf, a known electricity, ei-
ther from excited glass or sealing wax. If
they be divergent with the former, then the
approach  of a body  similarly electrified,
will augment the divergence, but  that of
one oppositely electrified will cause  their
collapse.
  The following is a table of several  sub-
stances which acquire the vitreous electri-
city, when we rub them  with those which
follow them in the list;  and the  resinous
electricity, when rubbed with those  that
precede them.
       The skin of a cat.
       Polished or smooth glass.
       Woollen stuff or worsted.
       Feathers.
       Dry wood.
       Paper.
       Silk.
       Lac.
       Roughened glass.
  No visible relation  can be pointed out
between the nature or constitution of the
substances,  and the species  of electricity,
which is  developed by  their mutual fric-
tion.   The  only  general law among the
phenomena, is, that the  rubbing, and the
rubbed body, always acquire opposite elec-
tricities.  Sulphur is  vitreously electrified
when rubbed with every metal except lead,
and resinously with  lead and every other
kind of rubber.  Resinous bodies, rubbed
against each other, acquire alternately the
vitreous and resinous electricity;  but, rub-
bed  against all other  bodies, they  become
resinously electrical.   White silk acquires
vitreous electricity with  black silk, metals,
and  black cloth; and  resinous with paper,
the human  hand, hair, and  weasel's  skin.
Black silk becomes vitreously electrical with
sealing-wax; but resinously with hare's,
weasel's, and  ferret's skins;  with brass,
silver, iron, human hand,  and  white silk.
Woollen  cloth is strongly  vitreous  with
zinc and  bismuth, moderately so with sil-
ver, copper, lead, and specular iron.   It it
resinous  with platina, gold, tin, antimony,
gray copper, sulphuret of copper, bisulphu-
ret of copper, sulphurets of silver, antimo-
ny, and iron. When two ribbons of equal
surface are excited by drawing one length-
wise over a part of the other; that which has
suffered  friction  in its whole length, be-
comes vitreously, and the other resinously
electrical.  Dry air impelled on  glass be-
comes  resinously electrical, and leaves the
glass in the opposite state. Silk stuffs, agita-
ted in the atmosphere with a rapid motion,
always take the resinous electricity, while
the air becomes vitreously electrified. A rib-
bon of white silk, rubbed against a well dyed
black one, affords always marks of vitreous
electricity,  but if the black silk be  much
worn, and the white ribbon be  heated,  it
will  yield  signs  of  resinous  electricity, 
ELE
ELE
and, on cooling, it will again exhibit marks
of the vitreous.  The general result which
was deduced by M. Coulomb,  from his
very numerous and exact experiments  on
this curious subject, is the following:—
  When the surfaces of two  bodies are
rubbed together, that  whose  component
parts recede least from each other, or ele-
vate least from their natural  position of
repose, appear, in consequence, more dis-
posed to assume the vitreous electricity;
this tendency augments if the  surface ex-
periences a transient compression.   Reci-
procally, that surface whose particles de-
viate most from  their ordinary position by
the violence of the other, or by any cause
whatever, is, for that reason, more disposed
to take the  resinous  condition.   This ten-
dency increases if the  surface  undergo  a
real dilatation.  The stronger is thi3 oppo-
sition of circumstances, the more energetic
is  the  development  of electricity, on the
two surfaces.  It grows feebler in  propor-
tion as their state becomes more  similar.
Perfect equality would nullify the pheno-
mena, provided it could exist.  Thus, when
a dry animal or vegetable substance is rub-
bed against a rough metallic surface, it ex-
hibits signs of resinous  electricity  In this
case, its parts are forcibly separated. When,
on the other hand, it is rubbed on a polish-
ed metal, which scarcely affects its surface,
 or merely compresses the particles, it ei-
 ther aflbrds no evidence of electricity, or
 exhibits the vitreous kind.  Heat, by dilat-
 ing the pores, acts on the  surfaces of bo-
 dies, as a coarser rubber would do.  It dis-
 poses them to take the resinous electricity.
 Thus also new black silk, strongly dyed,
 being rubbed against a ribbon  of white
 silk, takes  always the resinous electricity.
 But when the black stuff is worn, and the
 colour faded, if we open the pores of the
 white ribbon by heat, this acquires in  its
 turn a greater  tendency to the  resinous
 electricity than the black silk, and, conse-
 quently, makes it vitreous. This disposi-
 tion  vanishes, as might be expected, with
 the accidental cause that produced it,  and
 the white ribbon, on becoming cold, re-ac-
 quires the  vitreous electricity.   The black
 dye produces on wool the same effect  as
 on silk.  A white ribbon, rubbed against
 white woollen stuff, gives  always  signs  of
 resinous electricity; but, against wool dyed
 black, it aflbrds signs of the vitreous elec-
 tricity. I have entered somewhat minutely
 into the detail  of the  apparently trifling
 causes which give  birth to the one or the
 other electricity, as they may tend to throw
 some  light on  the electricities  evolved
 among chemical bodies by friction or  sim-
 ple contact.  It has been supposed, indeed,
 that uncombined acids,  alkalis,  and me-
 tals, are naturally and constantly in an elec-
    Yot.. 11.
trized condition, the  first  resinously, the
second and third vitreously.  But of this
position, there  is neither probability nor
evidence. The electricity produced by their
contact, on an extensive surface, with other
bodies,  is evidently a disturbance  of the
pre-existing equilibrium.  A wire connect-
ed with the most delicate  electroscope  of
torsion,  which  moves through  90° with
a force of less than l-100,00oth of a grain,
will indicate no electricity, when made to
touch the most energetic acid or alkaline
body.
   In  describing the two electricities,  we
must not omit the interesting observations
of Ehrman.  There are substances of the
imperfect conductor  class,  which are ca-
pable of receiving only one kind of elec-
tricity,  when made to form links  in  the
voltaic chain. M. Ehrman styled them uni-
polar bodies-  Perfectly dry soap, and the
flame of phosphorus,  when connected with
the two extremities of the voltaic appara-
tus, and with the ground, discharge only
the resinous electricity.  The flames of al-
cohol, hydrogen, wax and oil, discharge,
under like circumstances, only the vitre-
ous electricity.  All these bodies, however,
when connected with only one pofe of the
pile, and with the ground, destroy the di-
vurgence of the leaves of the electroscope
attached to that pole. To render these re-
 sults manifest, insulate  in dry  weather a
battery of about 200  pairs of plates.  Con-
nect with each extreme pole, the cap of a
 gold leaf electroscope, by a moveable wire.
 When  either  electroscope is  brought in
 contact with soap communicating with the
 ground, the slight divergence of the gold
 slips ceases.  But, when  the soap  is con-
 nected  with both electroscopes, and  also
 with the  ground, the divergence of the
 leaves of the electroscope, attached to the
 zinc end or  vitreously electrified pole, will
 continue, while the leaves of the other elec-
 troscope will collapse. The inverse order
 of effects occurs, or  the zinc electroscope
 collapses, when the flame of a taper is con-
 nected with both electroscopes, and with
 the ground.
   Mr  Brando, in an  ingenious paper pub-
 lished  in the Phil. Trans, for 1814, has en-
 deavoured to explain the curious phenome-
 na, with regard  to flames, in another way.
 As some chemical bodies  are supposed hy
 him to  be naturally in the resinous, and
 others in the  positive electrical state, he
 supposes tliat the positive flame will be at-
 tracted and neutralize the negative polari-
 tv, while the negative flame will operate a
 similar restoration  of the equilibrium at
 the positive pole.  To determine the truth
 of this  hypothesis, he placed the flames of
 various bodies between two insulated brass
 spheres, containing each a delicate thermo- 
ELS                                 JliLE
meter.  His first experiment verified Mr.  to the negative ball, both being feebly elec-
CuthbertS' >n's observation, that the  flame  trifled by a cylindrical machine of Nairne s
of a candle  communicates its heat chiefly  construction.
                              Flames attr
              Positive Ball.
Phosphurettcd hydrogen, slightly.
Carbonic oxide in a small stream, doubtful.
Ditto in large stream.
The acid from the flame of sulphur.
Flame  and acid fumes of phosphorus.
Stream of muriatic acid gas, shown by coat-
  ing the balls with litmus paper.
Stream of nitrous acid.
Vapour of benzoic acid.
 Ditto   of amber.
  "The flame of oil, wax," &c. says Mr.
Brande, "must be considered as consisting
chiefly of those bodies in a state  of va-
pour; and their  natural electricities being
positive, it is obvious, that when connected
with the positive pole of the battery, and
with a gold leaf electrometer, the  leaves
will continue to diverge; but when applied
to the negative  pole, that electrical state
will be annihilated by the inherent positive
energy of the  flame, and consequently the
leaves of the  negative electrometer will
not diverge. On the other hand, the flame
of phosphorus is negatively unipolar. Now
it has been shown that this  flame, (owing
probably to the rapidity with which it is
forming a powerful  acid, by combination
with a large quantity of oxygen), is attract-
ed by the positively electrified surface, and
consequently that it is itself negative, so
that  it would transmit negative electricity
to the  electrometer, but would annihilate
the negative power, and thus appear as an
insulator under the particular circumstan-
ces which M  Ehrman has described."  I
shall not stop  10 investigate the justness of
these ingenious conclusions.  They do not
affect the unipolarity of dry soap; which
on Mr. Brande's theory of that of flames,
should be naturally anil permanently in the
state of positive  electricity;  which  we
know it not  to be.
   III. Of the Distribution of Electricity.
   Under this head we shall be able to ar-
range several important phenomena, which,
by their disjunction, authors have frequent-
ly rendered complex  and  difficult of com-
prehension.   We  shall treat in  the  first
place, of the distribution  of either electri-
city, insulated in one body, and  in a sys-
tem  of bodies in  contact; in the  second
place, the distribution  of electricity  in a
system of contiguous bodies, not in con-
tact.
acted by the
               Negative Ball.
  Olefiant gas.
  Sulphuretted hydrogen, slightly;  its sul-
    phurous acid vapour passed off to the
    positive ball.
  Arsenuretted hydrogen; its arsenious acid
    passed feebly to the other ball.
  Hydrogen, result doubtful from equality of
    attraction.
  Flame of carburet of sulphur; its acid fumes
    passed to  the positive.
  Flame and alkaline fumes of potassium.
  Flame of benzoic acid.
  Flame of camphor.
  Flame of resins.
  Flame of amber.

    1. If we communicate electricity to an
  insulated metallic sphere, we shall  find the
  whole electric power diffused over its sur-
  face, and the particles in its interior, abso-
  lutely devoid of the  least  electric virtue.
  Let the ball of iron or  brass  have a hole
  of about an inch diameter, reaching to  its
  centre.   Then on touching the centre, with
  a metallic spherule attached to the end  of
  a needle of lac, and  instantly applying it
  to a delicate electroscope, we shall perceive
  no  sign  of electricity  whatever.   If the
  spherule, however, touch the  outer edge
  of the hole, or the surface of the globe  at
  any point, it will acquire a very manifest
  electricity.   Hence, if we apply for a mo-
  ment to  the surface of an electrified  24
  pound shot, two hemispherical cups of tin-
  foil, furnished with insulating handles, we
  shall find that the whole electrical virtue
  has passed into the  cups, whose weight
  may not  equal the ten-thousandth part of
  that of the ball.  This distribution is  to-
  tally independent of the nature of the sub-
  stance, and is deducible from the law dis-
  covered  by Coulomb, that electrical attrac-
  tions and repulsions, are inversely  propor-
  tional to the squares of the distances.
    If the  body be spherical,  the exterior
  electrical stratum, which always coincides
  with the  surface of the body, will  be the
  same with the thin stratum in  its interior.
  If the proposed spheroid,  be  an ellipsoid,
  the inner surface of the electrical stratum,
  will be also a concentric and similar ellip-
  soid; for it is demonstrated, that an ellip-
  tical stratum, whose  surfaces are thus con-
  centric and similar, exercises no action on a
  point placed in its interior.  The thickness
  of the layer  in each of  its points, is found
  generally determined by this construction.
  It  hence results,  that this  thickness is
  greatest at the summit of the greater axis,
  and  least at the summit of the  smaller. 
ELE
ELE
The thicknesses corresponding to the dif-
ferent summits, are to each  other, as the
lengths of their respective axes.
   2. Were the  atmosphere, and the glass
support, perfect non-conductors, the above
distribution would continue till some other
body was  brought near  to, or in contact
with, the ball.  But the surface of even
lackered glass, yields slowly to the idio-re-
pulsive power  of the electrical fluid;  and
the atmosphere, partly by its aqueous par-
ticles, and partly by its own feebly con-
ducting power, continually robs the globe
of its electricity.  The immediate aerial
envelope no sooner  acquires electric im-
pregnation,  than it recedes,  and is repla-
ced  by a new sphere of  gaseous particles.
By this intestine  aerial movement of re-
pulsion and attraction, the ball, in a short
time, loses its excess of  vitreous  or resin-
ous  electricity, and  resumes the neutral
state.  By placing it in the centre of a dry
glass receiver, the period of electrization
may  be prolonged,  but, sooner  or later,
the electric  equilibrium is  restored  be-
tween it, and the surrounding matter.
  3.  If we bring into  contact with  the
above electrized ball, an unelectrified  one
of the same bulk, but of a very  different
Weight, we  shall find an  equal distribution
to take place between them.  An  insula-
ted disc or spherule applied to the surface
of each, will be capable of affecting a gra-
duated electrometer of torsion, to  the
same degree.   We thus  perceive that bo-
dies do not  act on electricity, by  any spe-
cies of elective attraction or affinity.   They
must be regarded  merely as  vessels, in
Which this  power  is distributed,  agree-
able to the laws of mechanics.
  When the above globes are separated,
their electricities diffuse themselves  uni-
formly about them, and the quantities are
found equal when the surfaces are so.   But
if the surfaces  be unequal in any  given ra-
tio, it then  happens  that the quantity of
electricity varies in a different ratio, which
is less  than that  of the surfaces.   Thus
Coulomb ascertained, that when the sur-
face of the smaller globe was nearly one-
fifteenth of  that of the larger, its quantity
of electric  fluid was one-eleventh.  The
following is his general table of results:—
„  .    „ „,.        Density in little sphere,
Surface of Sphere.     vho.i surface L 1.
1	1
4	1.08
16	1.30
64	1.65
Infinite,	less than 2.00
    Do. calculated by M Poissor, 1.65
  The  difference  therefore  can   never
amount to two.  He placed two globes,
each of two inches diameter, in a line with
a globe of eight inches diameter; the two
 smaller ones being in  contact, and one of
 them with the larger.   He found that the
 quantity of electricity of the smaller globe,
 most distant from the greater, was to that
 of the intermediate, as 2.54  to  1.   Four
 globes of two inches being placed in a row,
 successively in  contact with each othei,
 and with  a globe of eight  inches diameter,
 the  ratio of the quantities  of electricity
 taken by the small globe, farthest from the
 large one, and that nearest it, was found to
 be 3.4 to 1.  Having placed 24 globes, each
 of two inches diameter,  in  a like series
 with the larger globe,  Coulomb compared
 the 24th little globe, that  is to say, the last
 in the row, with others in the same  row,
 and the results were as follow:—
        24th to the 23d as 1.49 to 1
        24th to the 12th as 1.7 to 1
        24th to the 10th as 2.1 to 1
       24th to the 1st
 which was in contact
 with the large globe,   as 3.72 to 1
       2*th to that of
 the large  globe,       as 2.16 to 1.

   When two electrified spheres, of equal
 size in contact, are examined as to the state
 of the electricity on the different points of
 their surfaces, we have the following rela-
 tions:—
 Position of the points    Ratio  of the second
     compared.        thickness to the first.
     90° and 20°           insensible
     90      30              0.2083
     90      60              0.7994
     90      90              1.0000
     90     180              1.0576
   If the diameters  of the two globes be as
 2  to 1.
     90° and 30°           insensible
     90      60              0.5882
     90      90              1.0000
     90     180              133 JJ
   That in ordinary cases, electricity is ct n-
 fined on the surfaces of bodies, not merely
 by the non-conducting faculty of the air,
 but  by a  species  of mechanical  pressure
 which air exercises, becomes evident, when
 we lessen the density of the air by exhaus-
 tion. Though the conducting aerial par-
 tides are thus greatly  diminished in num-
 ber,  rendering the insulation apparently
 more complete, yet the electric power now
 emanates  with vast rapidity, from the elec-
 trized ball, in visible coruscations   Rare-
 fied air is therefore a good conductor.
   4. By touching various  points of insula-
 ted electrized bodies  with a  Bttle disc of
 metallic foil, cemented to  die end of a nee-
 dle of lac, which he applied to hh  electro-
 meter, M. Coulomb ascertained the varia-
tion of electrical density, that exists at dif-
ferent points on the .surfaces of bodies,  of
different forms and magnitudes.  He thus 
ELE                                 ELE
found, that towards the extremities of all
oblong  concluding bodies,  whether thin
plates, prisms, or cylinders, there is a  ra-
pid augmentation of the electricity.   He
insulated a circular cylinder of two inches
diameter and thirty inches in  length, ter-
initiated at each end  with a hemisphere.
By comparing the quantities of electricity
accumulated at the centre, and at various
points, near to its extremities, he found
                       Ratio of the second
                      electrometric torsion
                         to the fir st.
Touched at the middle and
   2 inches from the end,  -    1.25
      And 1 from  do.   -    1.80
      And at the end,    -    2.30
   When the cylinder becomes more and
more  slender towards its extremities, the
increase of electricity becomes in  these
parts  more considerable, and more  rapid.
Lastly, if the extremity of the cylinder be
prolonged like the apex of a cone, the  ac-
cumulation which occurs at this point  be-
comes so strong, that the resistance of the
air is  no longer sufficient to retain the elec-
triei'\ on the suiface of the conducting
body, and it escapes in luminous  corusca-
tions, visible in the dark.  In this case, the
uniform distribution of electricity, extends
to a very small distance from  the pointed
extremity.   We thus perceive why bodies
furnished with  sharp projections, rapidly
lose the electricity communicated to them.
In like manner, a circular plate of five
inches diameter, when  electrified, has at
its centre an intensity of 1, at one inch
from  it  1.001, at two inches 1.005, at three
inches 1.17, at four inches 1.52, at four and
a  half inches 2 07, and at the border 2.9
times that of the centre.   We can thus
understand  how electrical machines, fur-
nished  with elongated prime  conductors,
furnish  very vivid sparks.
   2.  Of  the distribution of electricity
among contiguous bodies, not in contact.
   Let us examine first what happens when
two electrified spheres separated from con-
tact, are removed to a little distance from
each other.   A very remarkable phenome-
non is then developed.  We have seen, that
during  contact, the electricity is of  the
same nature on  the two spheres.  To fix
our ideas, left us suppose it to be vitreous.
We have likewise seen that it is null at the
point of contact  Now at the instant of se-
parating the two spheres, if their dimen-
siona be unequal, this nullity no longer ex-
ists.  A part of the combined electricity
of the  small sphere  is decomposed, and
that which is of a nature opposite  to the
electricity of the great sphere, namely the
resinous in  the present example, is carried
towards the point where the contact occur-
red.  This  effect diminishes according as
we remove the two spheres from one  ano-
ther, and it becomes null at  a certain dis-
tance, which depends on the ratio of their
radii.   Then the point of the little sphere,
where the contact was, passes back into its
state during the contact, that is to say, it
has no  species  of electricity.  Departing
from this term, if we augment the distance,
the electricity remains of the same nature
over the whole surface of the little sphere,
and that nature is the same  as  during the
contact.  These phenomena are always pe-
culiar to the  smaller of the two  spheres,
whatever may be the quantity of electrici-
ty communicated to  them.  On the larger
sphere,  the   electricity  is  always  and
throughout of the  same  kind, as at the
moment of contact.
  In an experiment made by Coulomb, the
great globe being eleven inches,  and the
small four  in  diameter, the opposition of
the two electricities continued till the dis-
tance became two inches.   When the di-
ameter of  the latter was only two  and a
half inches, the opposition  continued till
the distance became two and a half inches,
but not  beyond.   When the  globes are
equal, these peculiarities do not take place.
  When two  oppositely electrized spheres
are gradually  approached  towards  each
other, the thickness  of the electric coating
at the nearest points of their two  surfaces
becomes greater, and increases indefinitely
as their distance diminishes. The pressure
exercised  by the electricity, against the
plate of air interposed between the two bo-
dies,  augments  progressively, and termi-
nates by overcoming the resistance of the
air. The fluid then escaping under the form
of a spark or otherwise, must pass previous
to the actual  contact from  one surface to
the other.
  This  action at a distance is a key to the
principal phenomena of electricity.
   In our first inquiries we  remarked, that
electrized  bodies attract, or seem  to at-
tract, all the light matters presented to
them,  without its being necessary to de-
velop in  the latter the  elective faculty,
either by friction or communication.   But
now we must conceive that this development
is spontaneously effected, by the  mere in-
fluence at a distance of the electrized body,
on  the combined electricities of the  small
bodies around.   Thus  all the attractions,
whether real  or apparent,  which we ob-
serve, take place only  between electrized
bodies.
   When therefore an insulated conducting
body B, which  is in the natural state, is
put in presence of another insulated  elec-
trized body A,  the  electricity distributed
on  the  surface of A, acts by influence on
the two combined and quiescent  electrici-
ties of B,  decomposes a quantity of  them
proportional  to the  intensity of its action, 
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resolving it into its two constituent princi-
ples.  Of these two electricities become
free, A attracts the one,  and repeis the
other.  The second is carried to the por-
tion of the surface of B, which is most re-
mote from  A;  the first to the contiguous
surface.   These two electricities react in
their turn on the free electricity of A, and
even on  its   combined  electricities,  of
which one  part is decomposed by this re-
action, and  is  separated, if the body A be
also a conductor.  This new separation in-
duces a new decomposition of the combin-
ed electricity of B, and thus in succession,
till the quantities of each principle become
free, or the two bodies come into an equili-
brium, by  the  balancing of all the  attrac-
tive and repulsive forces, which they mu-
tually exercise, in virtue of their similar or
dissimilar nature.
   If A is vitreously electrized, and the con-
ductor B is a  cylinder, the end of it ad-
joining to A will  be resinous, and  the re-
mote end vitreous, while the middle portion
will be nearly neutral.
   If we now touch this remote end with a
third insulated conductor C, in the natural
state, and then remove it, we shall find it
charged with  vitreous electricity.   Or if
we touch  the remote end of the second con-
ductor with a finger, and after withdrawing
it separate the first and  second insulated
conductors, to  a considerable distance, we
shall find that B  has acquired electricity,
independent of the presence of A. Had we
not  touched it, however, then on putting
them asunder,  B,  no longer exposed to the
influence of A, would instantly recover its
natural state.  The two decomposed elec-
tricities would in  this case flow back from
the  extremities, and recombining, restore
the  equilibrium.  If A  was  vitreous,  the
touch of  an  unelectrified  finger, would
make B pass into the resinously electrical
state, by  opening a channel, so to  speak,
for the repelled vitreous electricity to es-
cape.  We see also, how this action and
reaction may prodigiously increase the in-
tensity of an electricity originally very fee-
ble.  On this principle we can at pleasure
communicate  to  an insulated conductor,
either of the electricities, from one electri-
fied  body  or source.
   Thus having excited a stick of sealing-
wax by rubbing it  on the sleeve of our coat,
we may make this resinous electricity pro-
duce either the resinous or the vitreous
state, in the gold leaves of an electroscope.
If we hold the stick at a little distance,
above  the  cap of  the  electroscope,  the
leaves will immediately  diverge,  and if
we then remove it, they will instantly col-
lapse.  If we now touch the cap for an in-
stant with the  sealing-wax, the leaves will
acquire the same electrical state; they will
continue divergent,  with resinous electri-
city.  Let us restore the natural state, by
touching the cap with our finger   Holding
again the  sealing-wax, a little above the
electroscope, let us then touch its cap for
a moment with our finger, and after remov-
ing it withdraw the wax, we shall perceive
the leaves continue to diverge, and on try-
ing the species of electricity, we shall find
it to  be the vitreous; for the approach of
excited wax  will make the divergence di-
minish, while that  of excited glass will
make it increase.
   These reciprocal attractions, repulsions,
and decompositions of the electrical com-
pound, explain perfectly the action of the
condenser  of electricity as  contrived  by
CEpinus or Volta, and improved by Cuth-
bertson; of the electrophorus; of the Ley-
den jar; and in some measure, of that mys-
terious apparatus, the voltaic battery.  To
this subject,  all our preceding electrical re-
searches may be considered  as  merely in-
troductory: for this  instrument constitutes
the great link between electricity and che-
mistry, deriving probably its  uninterrupted
series of impulsive  discharges, and conse-
quently its marvellous power of chemical
analysis, from the  conjoined agencies of
electricity, and elective attraction.
   IV. Of Voltaic Electricity.
   The accidental suspension  of  recently
killed frogs, by copper hooks to the  iron
palisades of  his garden, was the occasion
of the celebrated Galvani observing certain
convulsive movements, in the limbs of the
animals, which  no  known principle could
explain, and thenceforth of  opening up to
mankind, a rich and boundless field in phy-
sical science.-f  As  the practical nature of
this work  precludes us from entering into
historical details, we shall at once proceed
to describe the present state of voltaic elec-
tricity and  electro-chemistry.   Galvani  had
ascribed the muscular movements to a se-
ries of discharges, of a peculiar electricity,
inherent and innate in living beings, to
which the name animal electricity, or the
more  mysterious term galvanism, was for
some  time given.   Volta proved, that  the
phenomena proceeded  from  the contact of
the two dissimilar metals, copper and iron,
producing such a disturbance of the elec-
trical equilibrium, as  was sufficient to af-
fect the most delicate of all  electroscopes,
the irritability  of  a  newly killed  frog,

   f According  to  Wilkinson's history of
Galvanism, the  first galvanic phenomenon
observed, was that <<f  the taste excited on
the  tongue by  pieces of silv'-r and zinc;
and Galvani  was fim led into this oath of
investigation, which has immortalized his
name, by the convulsions observed in some
frogs, prepared for soup, and brought ac-
cidentally  near to  an electrical  machine,
from which sparks  were proceeding. 
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though it was insensible to every electro-
scope of human construction.   He  fully
verified this fine theory, by showing, that
a few contacts of the dissimilar  metals,
zinc and silver, in the  form of discs, fur-
nished with insulating handles, were capa-
ble of affecting the common condenser of
electricity.   Galvani, however, anxious to
defend his own hypothesis,  which linked
his name to the science, adduced some cu-
rious facts, which  proved, that  muscular
convulsions could be produced in the limbs
of dead frogs, altogether independent of
metals.   This led Volta to the further dis-
covery, that other dissimilar bodies, be-
sides metals, were capable by contact of
disturbing  the electrical equilibrium.
  Since a slender rod of silver and of zinc,
sink into the grave, they will shine forth on
the diadem of English science, companion
gems to the diamond of Newton.
  I shall now endeavour to give a brief sur-
vey of voltaic  phenomena, conducting my
steps, by the  researches of these philoso-
phers.
  There are six great eras in electro-che-
mical  science:—1. Its first  discovery by
Galvani;  2.  Volta's discovery of the contact
of dissimilar metals, disturbing the electric
equilibrium;  3. Volta's  invention of  the
pile; 4. The chemical power of this instru-
ment, first observed by Messrs. Carlisle and
Nicholson,  in  the decomposition of water;
5. The identity  of these chemical effects
with those producible by common electri-
city, first discovered and demonstrated by
touching each other at one of their ends, i Dr. Wollaston, in his  admirable " Experi-
  and at the other brought into contact with i
  the nerve and muscle, or spine and toes oft
  a dead frog, could excite powerful convul-'
  sions, it occurred to Volta, that a repetition
  on a more extended surface, of that simple
  series of  two metals  and moisture, might
  produce a combined effect, capable of be-
  ing felt by the human hand  By a  most
  philosophical  prosecution of his own  prin-
  ciple, he happily succeeded in constructing,
  by regular alternation of discs of silver,
  zinc, and moistened  cloth or  pasteboard,
  reared in  a columnar  form, the  electro-che-
  mical pile and battery, which will associate .
  the name of  Volta  to that of Galvani,
  through each  succeeding age.  The  com-
  pound metallic arcs  of copper and  zinc,
  with  which he connected a circle  of  cups
  containing salt-water, to form his couronne
  des tasses, may be regarded as the same ap-
  paratus,  in a horizontal, instead of a co-
  lumnar arrangement.  The former construc-
  tion was happily modified by Mr. Cruick-
  shanks into the voltaic trough; while the
  latter has  suggested the arrangement of
  parallel porcelain cells, into which a conca-
  tenated series of compound metallic plates
  is immersed.
    Amid the crowd of philosophers,  who,
  after Galvani  and  Volta, entered this ar-
( duous field, two are pre-eminent for the in-
I genuity and successof their investigations.
VDr. Wollaston and Sir H. Davy.  The first
  had the  singular  merit of tracing up the
ments on the  Chemical  Production and
Agency of Electricity;" and lastly, The ge-
neral laws of electro-chemical decomposi-
tion and transfer, revealed by Sir II. Davy,
in a series of memoirs, equally remarkable
for genius and industry.  It is but justice
to this philosopher to state that  the germ
of his most splendid discoveries, was ma-
nifestly formed and exhibited, immediately
after the construction of the pile  was an-
nounced.  Volta's celebrated  letter,  de-
scriptive of his invention, is dated Como,
March 20,  1800;  it was published in the
Philosophical Transactions, in the autumn
of that  year; and in  Nicholson's  Journal,
for September of the  same year, we have
an  important  communication  from Sir  H.
Davy, then Superintendent of the Pneuma-
tic Institution at Bristol.
   Mr. Carlisle having  been favoured, by Sir
Joseph  Banks, with  a  private  perusal of
Volta's letter, constructed a pile; and in the
beginning of  May, assisted by Mr. Nichol-
son, made several experiments on the de-
composition of water, and the reddening of
litmus by its means; but out of delicacy to
the Professor of Pavia, these were not pub-
lished till July.  Mr.  Nicholson, in a mas-
terly account of Volta's discovery, Mr. Car-
lisle's, and his own, says, " We had been
led by our reasoning on the first appearance
of hydrogen, to expect a decomposition of
the water; but it was  with no little surprise
that we found the hydrogen extricated at
analogy between the mysterious operations J the contact with one wire, while the oxygen
of galvanic, and of common electricity; and
afterwards invented an apparatus, by which
this agent can excite vivid  ignition, in al-
most a microscopic compass  Of the disco-
veries made by Sir H. Davy, in voltaic elec-
tricity, and in chemistry, by the sagacious
application of its unlimited powers, it is
difficult to speak  in  the cold language of
philosophy.   They probably surpass in  im-
portance, as they do  in splendour, the uni-
ted discoveries of preceding chemists; and
when the breath of contemporary envy shall
fixed itself in combination with  the  other
wire, at the distance of almost two inches.
This new fact still remains to be explained,
and seems  to point at some general  law of
the agency of electricity in chemical ope-
rations."
  " Struck," says Sir II. Davy,  " with the
curious phenomena noticed by Messrs. Ni-
cholson and Carlisle, namely, the apparent
separate production of oxygen and hydro-
gen from different wires, or from different
parts of the water completing the galvanic 
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 circle, my first researches were directed
 towards ascertaining, if oxygen and hydro-
 gen  could be separately produced  from
 quantities of water, not immediately in con-
 tact with each other."  He then proceeds
 to describe very ingenious and decisive ex-
 periments, in which he produced the dis-
 tinct  evolution of oxygen  and hydrogen,
 from  water  contained  in two separate
 glasses, even when the communication was
 made between them, through dead muscu-
 lar fibre, through his own body, or even
 through three persons.  He next submits
 water,  deprived  of its  loosely combined
 oxygen by boiling, to the voltaic pile, and
 obtains its two constituents in  a pure state.
    " Reasoning," says he  " on this separate
 production of oxygen and hydrogen, from
 different quantities of water, and on the
 experiments of Mr. Henry, junior, on the
 action of galvanic  electricity  on  different
 compound bodies, I  was led  to suppose,
 that  the constituent parts of  such bodies
 (supposing them  immediately decomposa-
 ble by the galvanic influence), might be
 separately extricated from the wires, and
 in consequence, obtained distinct from each
 other."  After submitting solution of pot-
 ash to the voltaic powers  of  100  pairs of
 small plates, without obtaining the expect-
 ed decomposition, he observes, " Surpri-
 sed at these results, which proved that no
 decomposition of potash had  taken place,
 and that that substance in this  mode of ope-
 rating, only enabled the  galvanic influence
 to extricate oxygen and hydrogen more ra-
 pidly from water, I was induced to operate
 upon this substance  in  the way of direct
 communication."  Still, only the water was
 decomposed, as we might now expect. He
 finally describes  the decomposition of wa-
 ter of ammonia,  as well as sulphuric and
 nitric, acids, and concludes by correcting an
 error into which  Dr. Henry had fallen, con-
 cerning a supposed decomposition of pot-
 ash.   " If," says he," the ratio between the
 quantities of oxygen and hydrogen pro-
 duced from  the different wires, be always
 the same, whatever substances are held in
 solution by  the water connected with them,
 this nascent hydrogen will become a pow-
 erful and accurate instrument of analysis."
    Dr. Wollaston coated the middle of a very
 /fine silver wire,  for  two or three inches,
[ with sealing-wax, and by cutting it through
 in the middle of the wax, exposed a section
/ of the. wire.  The two coated extremities
' of the wire thus divided, were immersed in
i a solution of sulphate of copper, placed in
 an electric  circuit between the  two con-
 ductors of a cylindrical machine; and sparks
 taken at l-10th of an  inch distance, were
 passed by means of them through the solu-
 tion.  After 100  turns of the  machine, the
 wire which  communicated with   (what  is
 called) the  uegative conductor, had a pre-
cipitate formed  on its surface, which  on
being burnished, was evidently copper; but
the opposite wire had no such coating.
  Upon reversing the direction of the cur-
rent of electricity, the order of the pheno-
mena was of course reversed; the copper
being shortly redissolved  by  assistance of
the oxidating power of positive  electricity
and a similar precipitate formed on the op-
posite wire.
   A similar experiment, made  with gold
wires —^.of an inch diameter, in a solution
of corrosive sublimate, had the same suc-
cess.
   If a  piece of  zinc and a piece of silver
have each one extremity immersed in the
same vessel, containing sulphuric or muri-
atic acid diluted with a large quantity of
water, the zinc is dissolved and yields hy-
drogen gas by decomposition  of the water;
the silver not being acted upon has no pow-
er of decomposing water; but whenever the
zinc and silver  are made  to touch,  or any
metallic communication is made between
them,  hydrogen gas is also formed at the
surface of the silver.  Any other metal be-
side zinc, which, by the  assistance of the
acid employed, is capable of  decomposing
water,  will succeed equall), if  the wire
consists of a metal on which the acid has
no effect.
   Experiments  analogous to the former,
and equally simple, may also be made with
man) metallic solutions.  If, for instance,
the solution contains copper,  it will be pre-
cipitated by a piece of iron, and will appear
on its surface.  Upon silver merely  im-
mersed in the same solution,  no such effect
is produced; but as soon as the two metals
are brought into contact, the silver receives
a coating of copper.
   In the explanation of these experiments,
says Dr. Wollaston, it is  necessary to ad-
vert to a point established by means of the
electric pile.  We know that  when water is
placed in  a circuit of conductors of electri-
city, between the two extremities of a pile,
if the power is  sufficient  to oxidate one of
the wires  of communication, the wire con-
 nected with the opposite  extremity affords
hydrogen gas.   Since the extrication of hy-
 drogen in this  instance,  is seen to depend
 on electricity,  it is probable that, in other
 instances, electricity may be  also requisite
 for its conversion into gas.  It would ap-
 pear,  therefore, that in  the solution of a
 metal, electricity is evolved during the ac-
 tion of the acid on it; and that the forma-
 tion  of hydrogen gas, even in  that case,
 depends on  a  transition  of  electricity be-
 tween  the fluid and the metal.
   We  see, moreover, in  the experiments
 with zinc, that  this metal, without contact
 of any other, has the power of decomposing
 water; and we  can have  no  reason to  sup-
 pose that the contact of the silver produces 
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 any new power, but that it serves merely
 as a conductor of electricity, and thereby
 occasions the formation  of hydrogen gas.
 In the next experiment, the iron by itself
 has the power of precipitating copper by
 means, it is presumed, of electricity evolv-
 ed  during its solution; and here likewise
 the silver, by conducting  the electricity,
 acquires  the  power of  precipitating the
 copper in its  metallic state.
  The explanation now given, with regard
 to these voltaic combinations of single pairs,
 receives  additional confirmation from the
 above comparative experiments with com-
 mon  electricity.   These  show, that the
 same transfer of chemical power, and the
 same apparent reversion of the usual order
 of chemical affinities in the precipitation of
 copper by silver, may be effected by a com-
 mon electrical machine.
  The chemical agency  of common elec-
 tricity is thus proved to be the same with
 the power excited by chemical means; but
 since  a difference had been  observed in the
 comparative facility with which the pile of
 Volta  decomposes  water,  and produces
 other effects of oxidation and deoxidation
 of bodies exposed to its  action,  Dr. Wol-
 laston was at pains to remove this difficul-
 ty, and succeeded in producing a very close
 imitation  of  the galvanic phenomena, by
 common electricity.
  It had been thought necessary to employ
powerful machines, and large Leyden jars,
for the decomposition of water; but when
 he considered that the decomposition must
 depend on duly proportioning the strength
of the charge of electricity to the quantity
of water, and that the quantity exposed to
 its action at the surface of communication,
depends on the extent of that surface; by
reducing this, he effected the decomposi-
tion of water by a much  smaller machine.
 Having procured a small wire of fine gold,
 and given it as fine a point as he could, he
 inserted it into a capillary glass tube, and
 after heating  the tube so as to make it ad-
 here to the point, and  cover it in  every
 part, he gradually ground it down, till with
 a pocket  lens  he  could  discover that the
 point  of the gold was exposed.
  The success of this  method exceeding
his expectations, he coated several wires in
 the same  manner, and found, that  when
 sparks from  the  conductors before  men-
 tioned were made to pass through water,
 by means of  a point  so guarded,  a spark
 passing to the distance of one-eighth of an
 inch,  would  decompose  water, when the
 point exposed did not exceed l-700th of an
 inch  in  diameter.  With  another   point
 which he  estimated at l-1500th, a succes-
 sion of sparks, l-20th of an inch in length
 afforded a current of small bubbles of air.
 But in every  way in which  he tried it, he
 observed that each wire gave both oxygen
and hydrogen gas, instead  of  their being
formed separately as by the electric pile.jl
  He is inclined to attribute the difference
in this respect to the greater intensity with
which it is necessary  to employ  common
electricity; for  that positive and negative
electricity so excited,  have each  the same
chemical  power as they are observed  to
have in the electric pile, may be  ascertain-
ed by other means.|2
  In the precipitation  of copper by silver,
an instance of deoxidation by negative elec-
tricity.has been  mentioned; the  oxidating
power of positive electricity may  be  also
proved by its effect on vegetable colours.
  Having  coloured  a  card with  a strong
  f 1 In my memoir on my theory of galvan-
ism, I suggested, that the decomposition of
water, which  Wollaston  effected by me-
chanical electricity, might not be the effect
of divellent attraction, like  those excited
by the poles of a voltaic pileibut of a me-
chanical concussion, as when Mres are dis-
persed by the discharge  of an electrical
battery.\ This opinion is confirmed by the
circumstance here mentioned, that  hydro-
gen and oxygen were given off at each wire;
and  also  by  some experiments, of Mr.
Singer, mentioned in his electricity, page
136.   According to him,  brass was sepa-
rated by an electrical discharge into cop-
per and zinc; metallic oxides were reduced,
especially oxide of tin.  It  cannot be al-
leged,  that, in  such  decompositions, the
divellent polar  attractions  are  exercised
like those which characterize the action of
wire proceeding from the poles of a voltaic
apparatus, f The particles were dispersed
from, instead  of being attracted to, the
wires, by which the influence was conveyed
among them.   This being  undeniable, it
can  hardly be  advanced, that we are  to
have one  mode of explaining the separa-
tion of the elements of brass by an elec-
trical discharge, another of explaining the
separation of the elements of water by the
same agent; one rationale when oxygen is
liberated from tin, and another  when libe-
rated by like means from hydrogen. J
  f2 Yet mechanical electricity is  always
far more intense than galvanic, if we may
judge by its striking distance, or length of
sparks, which  is   three  hundred times
greater with a good plate machine of ten
inches, than with the great pile of the Roy-
al Institution.   Indeed many who adopt
Wollaston's conclusions, and among others
Sir  II. Davy,  consider the  difference be-
tween  the  fluid, when evolved  by a pile,
and by a machine, to arise from  its being
more intense in  the one case, and more co-
pious in the other.  Wollaston  is, there-
fore, supposed to  produce  a resemblance
in the effects,  by increasing the  principal
feature of discordancy in their causes. 
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infusion of litmus, he passed  a current of
electric sparks along it, by means of two
fine gold points, touching it at the distance
of an inch from each other. The effect, as
in other cases, depending on the smallness
of the quantity of water, was most discern-
ible when the card was nearly dry. In this
state a very few turns of the machine were
sufficient to occasion a redness  at the po-
sitive wire,  very manifest to the naked eye.
The negative wire being afterwards placed
on  the  same spot, soon restored it to its
original blue colour.  By the voltaic pile,
the same effects are produced in a much
less time.
  Dr. Wollaston concludes, that all the dif-
ferences discoverable in the effects of gal-
vanic and common electricity, may be ow-
ing to the former being less  intense, but
produced in much larger quantity.
  A wire connected with the zinc extremity
of a voltaic pile of 50 or  100 pairs, being
made to touch the  brass cap of the elec-
troscope,  will cause the gold leaves instant-
ly to diverge with vitreous electricity; a
wire connected with the copper end  will
make them  diverge  with resinous electri-
city; but a wire from the middle of the pile
will have no effect on the electroscope.
  If wires of platinum  from the  opposite
extremities  of  the pile be  introduced  into
any solution of a neutral salt,  containing
acid,  united to alkaline,  earthy,  or com-
mon metallic matter; acid matter  will col-
lect round the  vitreously electrified  or po-
sitive surface; alkali, earth, or oxide, round
the resinously  electrified or negative  sur-
face.  If two separate vessels are employed
to contain the solution, connected by moist
asbestos, it is found that the arid collected
in the vessel containing the wire positively
electrified, will be in definite proportion to
the matter collected in the other cup; that
is, it will form with it a neutrosaline com-
pound.  If aqueous muriatic acid be acted
on by the wires, hydrogen  will separate at
the negative surface, and chlorine at the
positive.
  The preceding may be regarded as the
elementary  and fundamental  facts,  disco-
vered with  regard to  voltaic electricity.
Before  describing  its  greater and more
complex operations, we shall give an ac-
count of the various modifications of the
apparatus.
  In the original trough of Cruikshanks,
the contact of every pair of copper and zinc
plates was secured by soldering their sur-
faces together  Each compound  metallic
plate  being of a square form,  was fixed
tight  by cement into grooves cut in the
sides, and across the bottom, of the oblong
mahogany box.  The cells between every
pair of plates, were filled with the neutro-
saline or  acidulous exciting liquid.  The
   Vol. II.
difficulty of cleaning the surfaces of the
plates in this construction, and an idea that
the quantity of electricity was proportional
to the zinc surface exposed to oxidizement,
led  to  the  revival of the  Couronnes  des
lasses  arrangement.  In  this, the  square
plates of zinc and copper in each pair were
placed parallel to each other, at a distance
of  about half an  inch,  and soldered to-
gether at the middle of one  edge by a rec-
tangular narrow arc of copper.   Each pair
was fixed parallel to the preceding pair,
and at  a  distance corresponding  to  the
width of the cells in the  porcelain trough,
by screwing their rectangular arcs to a rod
of baked and well  varnished wood.  Ten
or a dozen pairs of plates, from four to six
inches diameter each, could thus  at once
be conveniently plunged  into, or removed
from, the exciting  liquid.  By  connecting
together a series of these troughs, a very
powerful battery  was obtained.  More re-
cently, Dr. Wollaston has rendered it pro-
bable that the igniting influence of the vol-
taic apparatus, is increased by placing op-
posite to both surfaces of the zinc, at the
distance of one-eighth or one-fourth of an
inch, a copper  plate.  At least the asto-
nishing power of ignition, exhibited by his
pair of small plates, seems to warrant that
conclusion.
  For compactness of structure,  and con-
venience in  use, I prefer the original ma-
hdgany box, and soldered pairs of plates,
of Cruikshanks.   The zinc surfaces may
be easily freed from adhering oxide, by  a
steel scraper of a proper shape.   Nor do
I find that this form of apparatus is nota-
bly inferior, in chemical  effect, to the se-
parate plates of the same size in porcelain
cells.  Dr. Hare of Philadelphia has lately
contrived an ingenious modification of Dr.
Wollaston's  single  igniting pair, which
from its great power  of exciting heat, and
its small electric intensity, he has styled  a
calorimotor.-j-
  When the  plates are  very large, they
must be constructed on the plan of the por-
celain trough.  In this way, Mr.  Children
arranged his  gigantic battery,  the most
magnificent  voltaic apparatus  which  the

   f On referring to the article Calorimo-
tor, it will be seen, that there is an essen-
tial difference between the action of a very
large galvanic pair and  a very small one.
The apparatus, which I contrived, is not  a
modification of Wollaston's.  His elemen-
tary battery and  the  calorimotor are  op-
posite modifications of the original galva-
nic pair. Mine is the proper  antipode (if  I
may be allowed  this word)  of De Luc's
electric column, while neither the  effects
nor the size of his apparatus would justify
us in thus characterizing it,
                       3 
ELE                                 ELE
 world has hitherto  seen.  It consisted of
 20 pairs of copper and  zinc  plates,  each
 plate  six  feet long  and two feet eight
 inches broad.  Each pair is joined at top
 by ribbons of lead,  and has a separate
 wooden cell.  They are suspended from a
 beam of wood, and having counterpoises,
 are easily raised or let down into  their
 cells.  The power of this battery was first
 tried on 2d of July  1813.  The cells were
 filled with water 60 parts, and a mixture of
 nitric and sulphuric acids one part, which
 was gradually increased till the quantity of
 acid  was  doubled.  Conductors of lead
 conveyed the electricity to an  adjoining
 shade, in which the  experiments  were
 made.  The power of the battery was pro-
 digious.  It  ignited  six feet in  length of
 thick platinum wire; but could not ignite
 an equal length of smaller platinum  wire.
 This  difference  was ingeniously ascribed
, by Dr. Wollaston, to the cooling influence
 of the air, acting more efficaciously on the
 slender mass of  metal.    Platinum,  in
 shorter lengths, was fused with great faci-
 lity.   Iridium was melted into a globule,
 and  proved  to  be  a brittle  metal.  The
 compound ore of iridium and osmium, was
 likewise fused, but not perfectly.  Charcoal
 kept at a white heat, in chlorine and chlo-
 rocarbonous gases, produced no change on
 them.  Neither tungsten nor uranium was
 any way changed by this vast battery.
   At a very  early period of his illustrious
 electro-chemical career, Sir H. Davy invent-
 ed various voltaic constructions, in which
 either only one metal was employed, or no
 metallic body at all.  Among the scientific
news inserted  in  the  Philosophical quarto
Journal for May 1801, we are told that  he
had formed piles, consisting of the single
metals, silver, copper, zinc, and lead; and
that one of the arrangement  was, a plate
of metal,  cloth soaked in dilute nitrous
acid,  cloth soaked  in  water, and cloth
soaked in  solution of sulphuret of potash;
then another plate of the same metal, and
the three  cloths  as  before.  It is  added,
that if a  trough  be  used  with  cells, and
the separation  between the  acid and  the
sulphuret of potash  be made by a plate of
horn, instead of the cloth imbibed  with
water, the two fluids may be connected  by
a slip of wetted cloth, hung over the upper
edge of the horn. This will complete the
communication, without occasioning any
mixture, because water is lighter than any
of the other fluids. A full account of these
new and  very curious  arrangements, was
published  in  the Philosophical  Transac-
tions for the above year, and  is copied into
the December Number of Nicholson's Jour-
nal.
  Silver or copper, in the above  construe"-
tion, forms an electrical apparatus, which,
with a series of fifty plates, will give shocks.
When the structure  is that of a  pile,  the
cloth  impregnated with the densest solu-
tion should be undermost in  each alterna-
tion;  and  solution of common salt in the
middle.
  The following tables contain some series,
which form voltaic electrical combinations,
arranged  in the order of their powers; the
most active substances being named first
in each column.
TABLES by Sir H. Davy, of some Electrial Arrangements, which, by com.
  baiation, form voltaic batteries, composed of two conductors, and one imper-
  fect conductor.
Zinc	Each of these is	Solutions of nitric acid.
Iron	the positive pole	of muriatic acid.
Tin	to all the metals	of sulphuric acid.
Lead	below it, and ne-	of sal ammoniac.
Copper	gative with res-	of nitre.
Silver	pect to the me-	other neutral salts.
Gold	tals above it in	
Platinum	the column.	
Charcoal		
TABLE II.— Of some Electrical Arrangements, consisting of one conductor
                    and two imperfect conductors.
Solution of sulphur	and potash	Copper	Nitric acid.
of potash		Silver	Sulphuric acid.
of soda		Lead	Muriatic acid.
		Tin	Any solution con-
		Zinc	taining acid.
		Other metals	
		Charcoal	
 
ELE
ELE
   The metals having the strongest attrac-
 tion for oxygen, are the metals which form
 the positive poie, in all cases in which the
 fluid menstrua  act chemically, by affording
 oxygen; but when the  fluid" menstrua  af-
 ford sulphur  to  the  metals,  the  metal
 having the strongest attraction for sulphur,
 under  the existing  circumstances,  deter-
 mines the positive pole. Thus, in a series
 of copper and iron, introduced into a por-
 celain trough, the  cells of  which are filled
 with water, or with acid solutions, the iron
 is positive, and the copper negative; but
 when the cells  are filled with solutions of
 sulphur and potash, the copper is positive,
 and the iron negative.
   In all combinations in which  one  metal
 is concerned, the surface opposite the acid
 is negative, while  that in contact With the
 solution of alkali and sulphur, or of alkali,
 is positive.
   Every one who has a perception of the
 beautiful in philosophical  research, must
 regard this important  law, discovered by
 Sir H Davy, with admiration.  It promises
 to lead us eventually into the mysteries of
 electro-chemical action, further  than any
 general principle hitherto  established.  It
 gives another fine  analogy  between elec-
 tricity and heat. For as the disengagement
 of the latter power is always proportional
 to the intensity of chemical  combination,
 so in the present case we see, that the in-
 tenser chemical action  is  connected  with
 the evolution of positive electricity,  while
 the feebler is associated with the negative.
 The positive electricity, if  we judge from
 the appearance of its light,  is the  more ac-
 tive of the two; and it is known to promote
 the most intense combinations  of bodies,
 viz. those with  chlorine, iodine, and  oxy-
 gen.
  The divergence of the leaves in the gold-
 leaf electroscope, and  more  exactly, the
 separation of the ball and disc in  the elec-
 trometer of Coulomb, are  proportional to
 the resilient force,  or intensity of the elec-
 trical agent.  Hence the repetition of a se-
 ries of moderate sized voltaic plates,  indi-
 cates the same repulsing energy on these
 instruments, as  the same  series of much
 larger plates.  With regard to imperfect
 conductors, like the human body, or nea-
 trosaline solutions,  the effects, namely, the
 shock, and transfer of the elements, are al-
 so proportional  to  the electrical intensity,
 or electroscopic indications. For these pur-
poses, we need not  enlarge  the  plates be-
yond  a  certain  size, which is relative to
the conducting  power  of the substances,
through which the  electrical energy  is to
 be transmitted.  But with  excellent con-
ductors, like charcoal and the metals, the
quantity of electricity, and not its state of
condensation, is to  be regarded.   The in-
tensity is essential,  to enable it to commu-
 nicate electrical polarities to a series of
 material liquid molecules, or to force its
 way, so to speak, through the animal frame.
 But  the same  intensity is altogether su-
 perfluous relative to metallic objects.  To
 operate changes on these, we must favour
 the evolution  of a  great mass of electri-
 cal power,  by using plates  of  extensive
 areas.
   To prove  the justness of these views, let
 us bring into action, by the same exciting
 liquid, a clean batterv of 20 pairs of 1 inch,
 and 20 pairs of lo inch plates.  On expos-
 ing a small  column of Water, in  a  glass
 tube, first to the one battery, and  then to
 the other, or on  connecting, with the two
 hands, first the extremities of the one, and
 then  those of the other, we shall perceive
 the evolution of £ases, or the shock, to be
 nearly equal.   While  the energy of the
 larger battery is acting on the water or hu«
 man  body, let two little cylinders, of char-
 coal, connected with the ends of the trough
 by metallic wires, be made to touch each
 other, the electrical excess  will be  suffi-
 cient to produce vivid ignition at the points
 of contact.   Silver  leaf may  be  substitu-
 ted for the charcoal, with a sirm'ar effect.
 The  little battery,  however,  eshausts its
 energy on the column of water.   When
 thus employed, it will  give  scarcely any
 sensation to  the fingers, ard produce no
 effect on  the charcoal or leaf.   E*en the
 battery of Mr. Children, which,  after  ig-
 nitiivj great lengths  of platinum wire, to a
 whiteness insupportable to the eye, fused
 it into globules;  and which emitted  from
 charcoal  a light more  dazzling  than the
 sunbeam, had  no more  effect on water,
 and the living body, than an  equal series
 of little plates.
   As  Mr. Children's battery  is  the  most
 powerful  in the world, in calorific effect, so
 that of 2000  pairs of plates, of 32  inches
 e.ich, furnished  by  the  subscription of a
 few patrons of science connected with the
 Royal Institution, is  the  most powerful yet
 constructed in electro-chemical intensity. The
 whole surface is 128000 square inches.
   This battery, when the cells  were filled
 with  60 parts  of water,  mixed with one
 part of nitric acid,  and one of sulphuric
 acid,  afforded a series of brilliant and im-
 pressive effects.   When pieces of charcoal,
 about  an inch  long, and  one-sixth of an
 inch  in  diameter,  were  brought  within
 l-30th or  l-40th of an inch of each other,
 a  bright  spark  was  produced, and more
 than half the volume of the charcoal  be-
 came  ignited  to whiteness; and by  drawing
 back the points a little from each other, a
 constant discharge took place, through the
 heated air, in a space equal at  least  to four
 inches, producing a most brilliant ascend-
 ing arch of light, expanded and conical in
the middle.   When any substance was in- 
ELE                                ELE
troduced into this arch, it  instantly  be-
came ignited.
  Platinum melted in  it, like wax in  the
flame of a  common candle.  Quartz,  the
sapphire, magnesia, lime, all entered into
fusion.  Fragments of diamond, and points
of charcoal and  plumbago, rapidly disap-
peared, and  seemed  to evaporate  in  it,
even when the connexion was made in a
receiver exhausted by the  air-pump;  but
there was no evidence of their having pre-
viously  undergone fusion.f

  f It is surpiising to  me, that the discor-
dancy of these phenomena, with any  that
have been produced by mechanical electri-
city, should not strike every electrician.  I
have exposed a  differential thermometer,
(made with ether according  to Dr. How-
ard's plan), to a  current of electricity from
a very powerful machine, without its indi-
cating the slightest change of temperature.
  Introducing the  thermometer  through
one of the necks of a receiver, a current
of electricity was made to pass from a wire
to a charcoal point, for ten minutes, with-
out any perceptible effect on  the warmth
of the air in the vessel.  The discharge  of
a battery produced a momentary depres-
sion of the fluid in the stem of the ther-
mometer; but it took  place, and ceased so
quickly, that I question if it were not  pro-
duced by the compression of the air around
the  bulb, or were not a dilatation due to
the rays of light simply.
   It appears, therefore, that heat does not
accompany a genuine electrical stream.  I
will venture to assert, that non-conducting
bodies  are never heated  by it, unless in
consequence of their  proximity to conduc-
tors, which are heated.  The appearance of
such immense quantities of caloric in these
experiments of Sir H. Davy, and the fusion
of quartz  and other non-conductors  can,
therefore, only be explained by supposing
it, no less than the electric fluid, a product
of galvanic action, and a constituent of the
 galvanic fluid.
   Indeed, that great philosopher considers
 it as irreconcilable with the materiality of
 caloric, that a wire should be ignited  for
 an unlimited time in vacuo. This inference
 does not follow,  if we suppose the wire to
 receive caloric from the apparatus, instead
 of supposing it only to receive electricity.
 Under the article caloric, in this work, I
 think 1 have demonstrated the materiality
 of that principle.  Those who concur in
 my conclusions on  tha*  subject, will, I
 trusi,  agree with me in deciding, that the
 unlimittd ignition of a wire,  in vacuo, by
 galvanic apparatus, proves the heat to be a
 concomitant product, not an effect of the
 electrical fluid.
   The following experiment I conceive to
 be very unfavourable to the idea, that gal-
  When  the  communication  between the
points, positively and negatively electrified,
was made in air rarefied in the receiver ot
the air-pump, the distance at which the dis-
charge took place increased as the exhaus-
tion proceeded, and when the atmosphere
in the vessel  supported only an inch of
mercury in the barometrical gauge, the
sparks passed through a  space  of  nearly
half an inch.   By making the  points  recede
from each  other, the discharge was made
through  6  or  7 inches, producing a most
beautiful coruscation of purple  light; the
charcoal became  intensely  ignited, and
some platinum wire  attached to  it, fused
with brilliant scintillations, and fell in large
globules upon the plate of the pump. All
the phenomena of chemical decomposition
were produced with intense rapidity, by
this combination.  When the  points  of
charcoal were brought near each other in
non-conducting fluids, such as oils, ethers,
and chloridic compounds, brilliant sparks
occurred, and elastic  matter was genera-
ted.  Such, indeed, was the electric inten-
sity,  that  sparks were produced, even in
good  imperfect  conductors,  such  as  the
nitric and  sulphuric acids.
   When the two conductors  from the ends
of the combination, were connected with a
 Leyden  battery, one with the internal, the
other with the external coating, the  battery
 instantly became charged; and on removing
the wire, and making  the proper connex-
 ions, either a shock or a spark  could  be
 perceived, and the least  possible time of
 contact  was sufficient  to renew the charge
 to its full  intensity.
   The general facts of the  connexion of
 the increase of the different  powers of the
 battery  with  the  increase of the number,
 and surface of the series, are very distinct;
 but to determine the exact ratio of the con-
 nexion, is a problem not easy of solution.
vanic ignition arises from a current of elec-
tricity.
  A cylinder of lead of about a quarter of
an  inch diameter, and about two  inches
long, was  reduced to the thickness  of a
common brass pin for about three quarters
of an inch.   When one end was connected
with one pole of the deflagrator, the other
remained suspended by this filament; yet
it was  instantaneously  fused by  contact
with the other pole.  As all the calorific
fluid which  acted  upon  the  suspended
knob, must have  passed through the fila-
ment by which it hung, the fusion could
not have resulted from a pure  electrical
current, which would have dispersed the
filament, as 1 have ascertained by trial, ere
a mass, fifty times  larger,  had  been per-
ceptibly affected.
  See passage  subjoined by me to this ar-
tide; also Galvanic Deflagrator. 
ELE
ELE
      MM. Gay-Lussac and Thenard announc-
   ed, that the power of chemical decomposi-
   tion increases only as the cube root of the
   number of plates; but  their experiments
   were made with parts of piles, says Sir H.
   Davy, very unfavourable for gaining ac-
   curate results.   In various trials made by
   him, with great care, in the  laboratory of
   the Royal Institution, the results were al-
   together different.
      The  batteries employed were parts of
   the above great combination, carefully in-
   sulated, and similarly charged; arcs of zinc
   and silver presenting  equal  surfaces, ar-
   ranged in equal glasses,  filled with the
   same  kind  of  fluid, were likewise used;
   and the tubes were precisely similar, and
   filled  with  the same  solution of  potash.
   In these experiments,  10  pairs of plates
   produced 15 measures of gas; 20 pairs pro-
   duced in the same time 49; again,  10  pairs
   produced five  measures; 40 pairs in the
   same time produced 78 measures.  In ex-
   periments made  with  arcs, and which
   seemed unexceptionable,
          4 pairs produced   1  measure of
                                 gas.
          12 in the same time 9-jo-
   When  6 produced        1
          30    -    -      24.5
      Now, these quantities are  nearly as the
   squares of the number of pairs.
      In  batteries, whose  plates have equal
   areas, the calorific power has been said to
   be as the number.  Sir H.  Davy, however,
   found that when the  surface of each  was
   100 square inches,
   10 pairs  ignited 2 inches  of plat,  wire
   l-80th of an inch.
   20   do.    do.   5 inches     do.   do.
   40   do.    do.  11 inches     do.   do.
      The  results of experiments  on higher
   numbers  were not satisfactory;  for 100
   pairs, of  32 square inches  each,  ignited
   three inches of platinum wire l-70th  of an
   inch; and 1000 ignited only 13 inches.   The
   charges of exciting acid, were  similar in
   both  cases.
      The ratio between the increase  of calo-
   rific power, and increased area of the plates,
   is probably greater than even the square.
   For 20 pairs of plates,  containing each two
   square feet, did not ignite one-sixteenth as
   much wire,  as 20 pairs, containing each
   eight square feet; the acid employed being
   of the same  strength  in both cases.   But
   great difficulties occur to ensure accuracy,
   in experiments on extensive  and powerful
   batteries.
      In  Sir H. Davy's great Bakerian Lecture
   on the chemical agencies  of electricity,
'~.  published in the Phil.  Trans, for 1807, and
f  most deservedly crowned by the  National
   Institute of France with the Napoleon prize,
   he amply demonstrated that acids, which
   are electrically negative, with  respect to
alkalis, metals, and earths, are separated
from these bodies in the voltaic circuit at
the positive pole; and  alkalis, metals,  and
earths, are separated from  acids, ut the
negative surface.  He  showed further, that
such are the attracting powers of these sur-
faces, that acids  are  transferred  through
alkaline solutions, and alkalis through acid
solutions, to the poles  where  they  have
their points of repose. This was exhibited
by making a  combination of three agate
cups, one containing sulphate  of potash,
one weak  nitric acid, and the third disulled
water.  The three ivere connected by as-
bes+us moistened in pure water, in such a
manner, that the  surface of the acid was
lower than the surface of the fluid, in the
other two cups.   When two wires of pla-
tina from  a powerful voltaic apparatus, are
introduced into the two extreme cups, the
solution of the salt being positively  elec-
trified, a decomposition took place, and in
a  certain time, a portion  of potash was
found dissolved in the cup, in contact with
the negative wire, though the fluid in the
middle cup  was still sensibly acid.
   Such are the chemico-analytical powers
of electricity, that not even insoluble com-
pounds are Capable of resisting their ener-
gy; for even glass, sulphate of barytes,  fluor
spar, gypsum, marble, &c when moistened
and placed in  contact with  electrified sur-
faces, from the voltaic apparatus, are sen-
sibly acted on, and the alkaline, earthy, or
acid matter, slowly  carried  to the  poles
in the common order. Not even  the  most
solid aggregates, nor  the firmest   com-
pounds, are capable of resisting this  mode
of attack.  Its operation is slow, but the
results are  certain, and, sooner  or  later,
by means of it, bodies  are resolved into
simpler forms of matter.
   Till Sir H.  Davy established the grand
law of electro-chemical decomposition, that
metals, inflammable  bodies, alkalis, earths,
and oxides, are determined lo the negative
surface or pole, and  oxygen, chlorine, io- ■  j
dine, and acids, to the positive pole, it had
been imagined  that various  substances
might be generated from pure w;<ter, by
means of electricity,  such as potash, soda,
and muriatic acid.  A strict investigation
of the circumstances under which  these
substances appeared, led him to discover
that they were always furnished  from the
vessels, or from  impurities in  the water,
and enabled him to determine the general
principles of electrical decomposition, and
to apply  this power to the resolution of se-
veral species of matter of unknown nature
into their elements,  namely  the alkalis,
earths, boracic and muriatic acids, &c.
   The intimate relation between the elec-
trical and  chemical changes, is evident
likewise in the general phenomena of the
battery.   The most powerful voltaic com- 
ELE                                 ELE
 binations are formed by substances that
 act  chemically,  with most  energy upon
 each other.  Such  substances as undergo
 no chemical changes in these combinations,
 exhibit no electrical powers.  Thus, zinc,
 copper and  nitric  acid, form a powerful
 battery; while  silver, gold, and  water,
 which do not act chemically on e:ich other,
 produce, in series of the same number, no
 perceptible effect.   These circumstances,
 in the infancy of galvanic research,  led to
 the  belief that the electrical phenomena
 were  entirely the  results  of  chemical
 changes; and that as heat was produced by
 chemical action, under  common circum-
 stances, so electricity resulted from it un-
 der other circumstances.
   This generalization seems, however, to
 be incorrect.  Zinc and copper, different
 metals and oxalic acid, different metals and
 sulphur or charcoal, exhibit electrical ef-
 fects after mere contact, and that in cases
 when not  the  slightest chemical  change
 can be observed.  If, in these  experiments,
 indeed, chemical phenomena are produced
 by the action of menstrua, all electrical ef-
 fects immediately cease.
   The source of action of the voltaic appa-
 ratus, seems to depend upon causes simi-
 lar to those which produce the accumula-
 tion  in the Leyden battery; namely, that in-
 fluence at a distance, or electrical induc-
 tion, which was fully treated of at the com-
 mencement of this article.   But its con-
 tinuous action, or  electro-motion, is con-
 nected  with the decomposition of the die-
 mical menstrua between the plates.   Each
 plate of zinc, in  the first  place, is  made
 positive, and each plate of copper negative,
 by contact; and all the plates are so arran-
 ged  with respect to each other, as to have
 their electricities  exalted by  induction,
 so that  every  single  polar  arrangement
heightens the electricity of every other po-
lar arrangement; and hence  the accumu-
 lation of power, or intensity, must increase
 with the number of the series.  When the
 battery  is connected in a circle, the  effects
 are demonstrated by its constant  exhibi-
 tion of chemical agencies, and the powers
exist as long as there is any menstruum to
 decompose.  But when it is insulated, and
the extreme poles of zinc and copper are
 unconnected, no effects  whatever are per.
ceived to take place, no chemical changes
go on, and it exhibits its influence only by
communicating very weak  charges  to the
electrometer; the zinc termination  of the
pole  communicating a positive charge, the
 copper termination a negative charge.
  A  beautiful experiment of Sir H.  Davy's
proves,  that each platt of tbe most  oxida-
 ble met:d in the apparatus, is in the iela-
 tion of posirve, and that each plate  of  the
 least oxidable, is in the relation of negative,
 while every series  is possessed of similar
 and equal polarity.  Forty rods of zinc of
the same size, connected  with forty silver
wires, precisely similar, were introduced
in the regular  order into similar glasses,
filled with a solution of muriate of ammo.
nia,  rendered slightly acidulous by muria-
tic acid.  As long as the extreme parts re-
mained unconnected, no gas was disenga-
ged  from  the  silver, and  the  zinc  was
scarcely acted upon.   When they were
connected, all the plates of zinc were dis-
solved much more rapidly, and  hydrogen
gas was evolved from  every silver wire.
In another experiment, in  which several of
these wires, at equal distances, were intro-
duced into small  glass tubes, it was found
that equal quantities of hydrogen were pro-
duced.
  There are no fluids known, except such
as contain water, which are capable of be-
ing made the  medium of  connexion be-
tween the metals or metal  of the voltaic
apparatus; and it is probable that the power
of water to receive double polarities,  and
to evolve oxygen and hydrogen, is neces-
sary to the constant operation of the con-
nected apparatus.  We may suppose also,
that acids or saline bodies increase the ac-
tion, by affording elements which possess
opposite electricities to each  other, when
mutually excited.   The action of the che-
mical menstrua exposes continually  new
surfaces of metal; and the electrical equili-
brium may be conceived, in consequence,
to be alternately  destroyed and restored,
the changes taking place in imperceptible
portions of time.
  We may  show the  manner  in which
aqueous fluids   propagate  electrical  po-
larity among their particles, by a very sim-
ple experiment.  Cut narrow filaments of
tin-foil  into lengths of almost half an inch,
and  place them in a line in the surface of
an oblong  trough of water. On  plunging
into  the water, at each end, wires connect-
ed with the two  extremities  of an active
voltaic battery, the metallic filaments  will
immediately acquire polarity.   Their posi-
tive and negative poles will become regu-
larly  opposed to  each other, the first de-
positing oxide, and the last  evolving hy-
drogen.  The analogy  with magnetic ac-
tions, is here very complete.
  That the decomposition of the chemical
agents is connected with the energies of
the pile, is evident from  all  the  experi-
ments that  have been  made.  No sound
objection has been urged against the theo-
ry, that the  contact of the metals destroys
the  electrical equilibrium, and  that  the
chemical changes restore  it; and, conse-
quently, that the action exists as  long as
the decompositions continue.
  Volta called  his  admirable invention an
electro-motive apparatus, founding his theo-
ry of its operation  upon the  Franklinian 
ELE
ELU
idea of an electrical fluid, for which certain
bodies  have  stronger  attractions  than
others.   He conceived that in his pile, the
upper plate of zinc attracts the electricity
from the copper, the copper from the wa-
ter, the water again from the next plate of
zinc, the next plate of zinc from the next
plate of copper, and so on.f1  This hypo-
thesis applies happily to most of the phe-
nomena of the action of the insulated pile,
and  the pile connected by either of its ex-
tremities  with the ground; but  does not
explain  with  the same facility, the powers
of the apparatus connected in a  circle, in
which each plate of zinc must be supposed
to have the same quantity of electricity as
each plate of copper;  for  it can only, as
Sir  H.  Davy  justly observes, receive as
much as the copper can give, unless indeed
the phenomena of the circular  apparatus
be considered as depending upon the con-
stant and rapid  circulation  of the natural
quantity of electricity in the  different se-
ries, which  requires  the  proof  of a con-
stant power to attract electricity from one
body, at the same time that it is given off
to another.  But the investigations of Cou-
lomb and Poisson, already detailed,  fully
demonstrate that electricity  is not distri-
buted among different species of matter,
by any kind of elective attraction.
  Platinum melts with more facility at the
positive than at the negative pole, when it
is connected with charcoal; but  with sul-
phuric acid, it becomes red-hot, only when
it is negative, and  the acid positive.  In
the calorific effect in  general, charcoal is
most easily ignited, next  iron,  platinum,
gold, then copper, and lastly, zinc.
  See Sir H. Davys Elements, and M. Ri-
ot's Traite1 de Physique, tome ii. chapitre 16;
Effects  chimiques de  VJppareil  electromo-
tcur*
  +  I conceive that the galvanic fluid owes
hs properties to caloric and electricity; the
former  predominating in proportion to the
size of  the pairs, the  latter in proportion
to the number, being in both cases excited
by a powerful acid.   Hence  in  batteries,
Which  combine both  qualifications suffici-
ently, as in  all those intervening between
Children's large  pairs of two feet eight
inches by six feet, and the 2000 four-inch
pairs of the Royal  Institution, the pheno-
mena indicate the presence of both fluids.
In De Luc's column, where the size of the
  fi If the zinc attract electricity from the
eopper, it has a stronger affinity for elec
tricity. The water attracts electricity from
the zinc; it has then a stronger affinity for
it than  zinc; and a fortiori  stronger than
copper, whose affinity is  weaker than  that
of zinc.  Copper cannot then attract elec-
tricity from water by the premises.
pairs is insignificant, and the energy of in-
terposed agents feeble, we see electricity
evolved without any appreciable quantity of
caloric. In the calorimotor, where we have
size only, the number bt ing the lowest pos-
sible, we are scarcely able to detect  the
presence of electricity.
   When the fluid contains enough electri-
city to give a projectile power, adequate
to pass through a  small  space in the  air,
or through charcoal, which impedes or ar-
rests the caloric, and favours its propensity
to radiate, this principle is evolved.  This
accounts for the evolution of intense heat,
under those circumstances, which rarefies
the  air, sO that the length of the jet from
one pole to the other may be extended af-
ter its commencement.  Hence the portions
of the circuit  nearest to the intervening
charcoal or heated space, are alone injured;
and even non-conducting bodies, as quartz,
introduced into it  are  fused; and hence a
very large wire may be melted by the fluid,
received through  a small wire impercep-
tibly affected.
  See my memoirs on the Calorimotor & Gal-
vanic Deffagrator in Silliman's Journal.^

  * We shall retain the title Galvanism,
out of respect to its illustrious discoverer,
and place under it, some details concerning
the influence of this form of electricity on
living bodies.*  f See Galvanic Defla-
GRATOR.f
  * Electrum.   See  Ores of Gold.*
  Elements.   A term used by the ear-
lier chemists, nearly in the same sense as
the  moderns use  the  term first principle.
The chief, and indeed  very essential diffe-
rence between them is, that  the ancients
considered  their elements as bodies pos-
sessing absolute simplicity, and capable of
forming all other bodies by their mutual
combination; whereas  the  first principles
of the  moderns are considered as simple,
merely in respect  to the present state of
the art of analyzing bodies.
   ' Elemi.  A resin,  winch  exudes from
incisions made, in  dry weather,  through
the  bark of the amyrit elemifrra,  a tree
which grows in America.  It is wrapped in
flag leaves, in long roundish cakes, semi-
transparent, and of a yellow colour.  It has
a faint  fragrance.*
   Eliqvation.  An operation, by means
of which a more fusible substance is sepa-
rated from  another which  is  less fusible.
It consists in the application  of a degree
of heat sufficient to fuse the  former,  but
not the  latter.
   Elutriatiosj.  This word is used by
chemists to denote the process of washing,
which carries off the lighter earthy  parts,
while the heavier metallic parts subside to
the bottom. 
EME
ENA
   * Emerald.  This genus contains two
 species, the prismatic and rhomboidal.
   1. Prismatic Emerald, Kuclase of Haiiv.
 Its colours are green, of various  shades,
 and sometimes sky-blue.  It is found  only
 crystalli/.-d. The primitive form is a prism
 of 133" J i'.  Its  secondary forms  are, an
 oblique four-sided prism, variously modifi
 ed by  accumulations and truncations  The
 lateral planes are more or  less  longitudi-
 nally streaked, giving the  prisms  a reed-
 like appearance.  Lustre splendent.  Cleav-
 age perfect, in the direction of the smaller
 diagonals  of  the prism.   Fracture small
 conchoidal.  Fragments tabular.  Transpa-
 rent. Refracts double. Harder than quartz,
 but softer than  topaz.  Easily  frangible.
 Sp. gr. 2.9 to 3.3. Loses transparency, and
 then melts before the blow-pipe.  Its  con-
 stituents are 35 to 36 silica,  18  to  19  alu-
 mina, 14 to 15 glucina, 2 to 3 iron, and 27
 to 31 loss.   The  last is chiefly water,  and
 in some measure alkali.   Found in Peru
 and Brazil.   It is a beautiful  mineral,  but
 too brittle  for jewelry.
   2. Rhomboidal  Emerald,  of which there
 are two sub-species, the precious emerald
 and the beryl.   Precious  emerald  is well
 characterized by  its emerald-green colour,
 of various depths.  It is  generally crystal-
 lized.  The primitive form is  an equiangu-
 lar six-sided prism, on which various trun-
 cations are found.  The lateral planes are
 smooth; the terminal planes rough.  Lustre
 splendent.  Cleavage straight and four fold.
Fracture imperfect conchoidal.   Transpa-
rent.  Moderate double refraction.  Nearly
as hard as topaz. Sp. gr. 2.6 to 2.77. Heat-
ed to  a moderate degree, it becomes of a
 blue colour, but recovers  its tint on cool-
ing.  At a  high heat, it fuses into a white
vesicular glass.  Its constituents are, silica
 64.5,  alumina  16,  glucina  13,  oxide of
chrome 3.25, lime 1.6, water  2.   Klaproth
 found 1. of oxide  of iron. It occurs in drusy
cavities, along with iron pyrites, calcareous
 spar, and quartz,  in veins that traverse clay-
 slate.   The most beautiful emeralds come
 from Peru.   As a gem, it is valued next to
the ruby.   See Beryl, in its alphabetical
place.*
  * Emert.  A sub-species  of rhomboidal
corundum.   Its colour  is intermediate be-
 tween  grayish-black, and  bluish-gray.   It
 occurs  massive and disseminated, and  also
in granular concretions.  Lustre glistening
 and adamantine.  Fracture fine grained un-
even.   Translucent on the edges.  So very
hard as to  scratch topaz.  Difficultly fran-
gible.   Sp. gr. 4.0.  Its constituents  are 86
alumina, 3  silica, 4 iron, and 7 loss.  In
 Saxony, it occurs in beds of talc and stea-
tite.  It  occurs abundantly  in the Isle of
Naxos,   and also  at Smyrna.   It is used for
 polishing hard minerals  and  metals.   Its
fine powder is obtained by trituration and
elutrialion.*
   ♦ Emetin.  Digest ipecacuan root, first
in  ether and then in alcohol.  Evaporate
the alcoholic infusion to dryness, redissolve
in water, and drop in acetate of lead.  Wash
the precipitate,  and then diffusing it in wa-
ter, decompose by a current of sulphuretted
hydrogen gas.   Sulphuret of lead  falls to
the bottom, and the  emetin remains in solu-
tion.   By evaporating the water, this sub-
stance is obtained pure.
   Emetin forms  transparent  brownish-red
scales.  It has no  smell, but a bitter  acrid
taste.   At a  heat somewhat  above  that of
boiling water, it is  resolved into carbonic
acid, oil and  vinegar.  It aflbrds no ammo-
nia  It is soluble both in water and alcohol,
but not in ether; and uncrystallizable.  It
is precipitated by  proto-nitrate of mercury
and corrosive sublimate, but not by  tartar
emetic.  Half a  grain of emetin acts as a
powerful  emetic,  followed  by sleep ; six
grains vomit  violently, and produce  stupor
and death.   The  lungs and intestines are
inflamed.  Pelletier and  Magendie, Ann. de
 Chimie et Physique, iv. 172.*
   E ipthkuma.   'I his term is applied to de-
note the peculiar smell produced by a con-
siderable heat upon vegetable or animal sub-
stances in closed  vessels,  or  when burned
under circumstances which prevent the ac-
cess of air to a considerable part of the mass,
and consequently occasion an impeifect com-
bustion, or  destructive  distillation  of the
parts  so covered up by the rest of the mass.
   Emulsion.   An imperfect combination of
oil and water, by the intervention of some
other substance capable of combining  with
both these substances.  The substances are
either saccharine or mucilaginous.
   Examel.  There are two kinds of enamel,
the opaque and the transparent.  Transpa-
rent enamels are usually rendered  opaque
by adding putty,  or the white oxide of tin,
to them.  The basis of all enamels is there-
fore a perfectly transparent and fusible glass.
The oxide of tin renders this of a beautiful
white,  the perfection of which  is  greater
when a small quantity of manganese is like-
wise added.   If the oxide of  tin be not suf-
ficient  to destroy the transparency  of the
mixture, it  produces a semi-opaque  glass,
resembling the opal.
   Yellow enamel is formed by the addition
of oxide  of lead,  or antimony.  Kunckel
likev ise affirms, that a beautiful yellow may
be obtained from silver.
  Red enamel is afforded by the oxide of
gold, and also by that of iron   The former
is the  most  beautiful, and  stands the fire
very well, which  the latter does not.
  Oxide of copper affords a green;  manga-
nese,  a violet; cobalt, a blue,  and  iron, a
very fine black.   A mixture  of these diffe-
rent enamels produces a great variety of in-
termediate colours, according to their na-
ture and proportion.  In this branch of the
art, the coloured  enamels are sometimes
mixed with each other, and  sometimes the 
EPI
EPI
uxides are mixed before they are added to
the vitreous bases.
  * In the  transactions  of the  Society of
Arts for 1817, a valuable list of receipts tor
enamel colours is given by Mr. R. Wynn,
for the communication of which a premium
was awarded. The following are Mr. Wynn's
fluxes:—

    No. 1.  Red lead,          8 parts.
           Calcined borax,    1$
           Flint powder,      2
           Flint glass,        6
    Xo. 2. Flint glass,       10
           White arsenic,     1
           Nitre,             1
    No. 3. Red lead,          1
           Flint glass,        3
    No. 4. Red lead,          9J
           Borax not calcined, 5$
           Flint glass,         8
    No. 5. Flint glass,        6
           Flux, No.  2.       4
           Red lead,           8
   After the fluxes have been melted, they
should be  poured on a flag stone, wet with
a sponge; or into a large pan of clean water,
then dried, and finely pounded in a biscuit-
ware  mortar for use.
    Yellow enamel.
       Red lead,                     8
       Oxide of antimony,            1
       White oxide of tin,            1
   Mix the  ingredients well in a biscuit-ware
mortar, and having put them on a  piece of
Dutch tile  in the muffle, make it gradually
red-hot, and suffer it to cool.  Take of this
mixture 1, of flux No. 4. 1$; grind them in
water for use.  By varying the proportions
of red lead and antimony, different shades of
colour may be obtained.
    Orange.
       Red lead,                 12
       Red sulphate of iron,       1
       Oxide of antimony,          4
       Flint powder,               3
   After  calcining these  without   melting,
fuse 1 part of the compound with 2£ of flux.

     Dark red.
       Sulphate of iron calcined dark,
Flux, No. 4. 6 parts Colcothar, 1	i of this
Light red. Red sulphate of iron, Flux, No. 1, White lead,	1 3
Brown. Manganese, Red lead, Fhnt powder,	2* 84 4
See transactions of the  Society, or the
   VOL. II,
Phil. Mag.  vol. 51.  Mr.  Tilloch justly ob-
serves, that borax should be used sparingly,
as it causes efflorescence, and decay of the
enamel colours.*
  Ektkochi.  A genus of  extraneous fos-
sits, usually of about an  inch in length, and
made up  of a number of round joints, which
when separate and loose, are  called trochi-
tsc:  they are composed of the same kind  of
plated spar with the fossil shells of the echi-
ni, which is usually of a bluish-gray colour,
and  are  v>ry  bright  where fresh broken;
they are  all striated from the centre to the
circumference, and have a cavity in the mid-
dle.  They seem to be the  petrified arms  of
that singular  species of the  sea  star-fish,
called Stella arborescens.
  ♦Epidote.   Pistacite.— Werner.   A sub-
species of  prismatoidal augite.—Jameson.—
Acanticone, from Norway.   Colours,  pista-
chio green, and green  of  darker  shades.
Massive,  imfistinc. granular or fibrous con-
cretions, and ciystallized.   The  primitive
form is an oblique four-sided prism,in which
the lateral  planes meet at angles of 114° 37'
and 65° 23'.   The secondary forms are,  1.
Very oblique four-sided prisms, bevelled  on
the extremities.  2. That figure  truncated
on the acute edges, and flatly bevelled on the
extremities.   3. A broad unequiangular six-
sided prism, variously acuminated or trun-
cated.   4.  A very oblique four-sided prism,
truncated on the obtuse  lateral edges, and
doubly acuminated on  the extremities  by
four planes.  The  crystals are sometimes
reed-like, and the lateral planes are longitu-
dinally streaked; but  the  truncating, acu-
minating, and bevelling planes, are smooth,
and the terminal planes diagonally streaked-
Lustre splendent,  internally inclining  to
pearly.  Cleavage  twofold.   Fracture flat
conchoidal. Translucent.  Harder than feld-
spar, but not  so hard  as quartz.  Brittle.—
Sp. gr.  3.45.  Before the blow-pipe, it is
converted into  a brown  coloured scoria,
which becomes black with  heat.  Its consti-
tuents are  silica 37,  alumina 21, lime 15,
oxide  of iron 24, oxide of manganese 1.5,
water 1.5. Laugier found 26 alumina,  20
lime, and 13 oxide of iron.   It occurs in pri-
mitive beds and veins, along with augite,
garnet, hornblende, calcareous spar, copper
pyrites,  &cc.  It is found in Arran, in secon-
dary syenite  and clay-slate; in Mainland of
Shetland, in syenite; "in the Island oflcolm-
kill, in a rock composed  of red feldspar and
quartz;  in the syenite  of Glencoe; in simi-
lar rocks among the Malvern hills; in quartz,
at  Wallow Crag, near  Keswick; in  Corn-
wall;  Arendal,  in Norway;  in  Bavaria,
France,  &c*
   Ei'idebmis.  If the human skin be  mace-
rated  in hot water,  it  separates into two
parts, the  cutis, or true skin, and the epider-
mis, or scarf skin.  The continued action of
warm water  at length dissolves Che cutis, 
EQU                                   EQU
but does not affect the epidermis,  neithev
does alcohol.  Caustic alkali,  however, dis-
solves it.  It resembles coagulated albumen.
  Epsom Salt.  Sulphate of magnesia.
  * Eai'ivALEffTR (Chevical). A term hap-
pily introduced into chemistry by Dr. Wol-
laston, to express the system of definite ra-
tios, in  which the corpuscular subjects of
this science reciprocally combine, referred
to a common standard,  reckoned unity.  If,
with this profound philosopher, we  assume
oxygen  asihe standard, from its almost uni-
versal relations  to chemical matter; then
calling it unity, we shall have, in thefollovy-
ing examples^ these ratios reduced to their
lowest terms, in which the equivalents will
be Prime ratios :—
  The lowest ratio, or equiva-
lent prime of oxygen being
That of hvdrogen will be
     Offluor?'
     (If carbon,
     Of phosphorus,
     Of azote,
     Of sulphur,
     Of calcium,
     Of sodium,
     Of p' tassium,
     Of copper,
     Of barium,
     Of lead,
 1.000

 0.125
 0.375
 0.750
 1.500
 1.750
 2000
 2.550
 2.950
 4.950
 8.00
 8.75
13.00, &c
  The substances in the above table, sus-
ceptible of reciprocal  saturation, can com-
bii.e with  oxygen or with  each other, not
only in proportions corresponding  to  these
numbers,  but also frequently in multiple or
sub-multiple proportions.  We  have there-
fore two distinct propositions on this nter-
esting subject.
  1st, The general reciprocity of the satu-
rating proportions.                      V
  2d, The multiple  and submultiple  pro-
portions of prime equivalents, in which any
one body  may unite with any other body, to
constitute successive binary compounds.
  The first proposition, or grand law of che-
mical combination, was discovered by J B
Richter of Berlin, about the year 1792.  The
second, of equal importance, and  more re-
condite, was discovered so early as the year
1790, by Mr. W. Higgins.
  Richter inferred his  from the remarkable
and well established fact, that two neutral
salts, in reciprocally decomposing each other,
give birth to  two new saline  compounds,
always perfectly neutral.  Thus, sulphate of
soda being added to muriate of lime, will
produce perfectly neutral sulphate  of lime
and muriate  of soda.   The  conclusions he
drew were, 1st, That the quantities of two
alkaline bases, adequate to neutralize  equal
weights of any one acid, are proportional to
the quantites of the same bases, requisite to
  neutralize the same weights of every other
  acid.  For  example, 6 parts of potash,  or
  4 of soda,  neutralize 5 of  sulphuric acid;
  and 4 4 of  potash are adequate to the satu-
  ration of 5 of  nitric acid.  Therefore,  to
  find the quantity of soda equivalent  to the
  saturation of this weight of  nitric acid,  we
  need  not  make experiments,  but merely
  compute it  by the proportional rule of Rich-
  ter. Thus, as 6: 4.4 :: 4 : 2.93; or in words, as
  the potash  equivalent to the sulphuric acid,
  is to the potash equivalent to the nitric acid,
  so is the soda equivalent to  the first, to the
  soda equivalent to the second.   And again,
  if 6.5 potash saturate 5 of muriatic acid gas,
  how much soda, by Richter's  rule, will be
  required for the same effect.  We say 6.6.5::
  4: 4.3.  3dly, If 10.9 potash  combine with 5
  of carbonic acid, how much  soda will be
  equivalent to that effect. Now, 6 : 10.9 :: 4:
  7.26.  Here, therefore, we have found, that
  if 6 potash be equivalent to  4  soda, in satu-
  rating 5 of  sulphuric acid, this ratio of 6  to
  4, or 3 to 2, will  pervade all the possible
  saline combinations; so that whatever be the
  quantity of  potash requisite to saturate 5,10,
  &c. of any  other acid, two-thirds of that
  quamity of soda will  suffice.
    In the same manner let us  find out, for
  five of sulphuric, or of any  one  standard
  acid, the saturating  quantity  of ammonia,
  magnesia, lime,  strontites, barytes, peroxide
  of copper,  and the other bases; then their
  proportions to potash, thus ascertained, for
  this acid,  will,  by arithmetical reduction,
  give their saturating quantity of every other
  acid, whose relation to potash, or indeed  to
  any one of these bases, is known.
    The experimental verification of this most
  important law, occupied  Richter from the
  year 1791 to the year 1802^ in  which period
/ne puoltshedpTn" successive parts, a curious
  work, entitled the Geometry of the Chemi-
  cal Elements, or Principles of Stechiometry.
  We might have expected greater  accuracy
  in his investigations, from the circumstance,
  that Dr. Wollaston selected his statement of
  the constituents of nitre, in preference  to
  those of all  other chemists, in  the construc-
  tion of his admirable table of chemical pro-
  portions.
    With indefatigable zeal Richter examined,
  by experiment,  each  acid, in its relation to
  the bases,  and  then compared the results
  with those given by calculation, presenting
  both in an extensive series of tables.
    It is curious that he does not seem to have
  been aware, that all  his tables might have
  been reduced into a single one, of  21  num.
  bers, divided into two columns, by means  of
  which, every question relating to the inclu-
  ded articles, might be solved by the rule  of
  three, or a sliding scale.  The following ta-
  ble, computed by Fischer from Richter's last
  tables,  was  inserted by the celebrated Ber-
  tholiet in a  note to his chemical statics. 
EQU                                   EQU
Bases.		Oxygen = 1.	Acids.		Oxygen = 1.
Alumina,	525	2.625	Fluoric,	427	2 135
Magnesia,	615	3 075	Carbonic,	577	2.885
Ammonia,	672	3.36	Sebacic,	706	3.530
Lime,	793	3.965	Muriatic	712	3560
Soda,	859	4.245	Oxalic,	755	3.775
Strontian,	1329	6 645	Phosphoric,	979	4.895
Potash,	1605	8.025	Formic,	988	4.94
Barytes,	2222	1.111	Sulphuric,	1000	5.000
			Succinic,	1209	6.045
			Nitric,	14i.:5	7.025
			Acetic,	148J	7.400
			Citric,	1683	8.415
			Tartarcous,	1694	8.470
  I have added the two columns under oxy-
gen, from which we  see at once, that  with
the exception of the bases lime, strontian,
and soda, and the acids carbonic,  muriatic,
sulphuric,  nitric,  citric,  and  tartaric;  the
numbers given by Richter do not form tole-
rable approximations to  the true  propor-
tions.  The object of the above table was,
to give directly the quantities of acid and al-
kali requisite for mutual saturation.  For ex-
ample, 1605, opposite to potash,  is the quan-
tity of that alkali equivalent to neutralize
427 of fluoric acid, 577 carbonic, 712 muri-
atic, 1000  sulphuric, &c.  Each column af-
fords also progressively, increasing  numbers.
Those nearest the top have the greatest acid
or alkaline energies,  as measured  by  their
powers of saturation.  The column of Rich-
ter gives, therefore, as far as the  analytical
means of his time permitted, a  table of the
relative weights of what has since  been hy-
pothetically called the atoms.  j^Cs.
   2.  But  two chemical constmients  fre-
quently unite in different proportions, form-
ing distinct and often dissimilar compounds.
Thus, oxygen and azote constitute in one
proportion, nitrous  oxide, the intoxicating
gas of Sir  H.  Davy;  in a second proportion,
nitric oxide, the nitrous gas of Priestley; in a
third proportion, nitrous acid; and in a fourth
proportion, nitric acid.  Is there any law re-
gulating  these various compounds; so  that
knowing the first proportion, we may  infer
the whole series ?  This question  was  first
answered in a work containing many curious
anticipations of discoveries, to which poste-
rior  writers have  laid  claim; I mean  Mr.
Higgins's Comparative View of the Phlogis-
tic  and  Antiphlogistic Theory, printed in
1788, and published  early in 1789.  Besides
some additional facts, decisively hostile to
the hypothesis of phlogiston, this publication
distinctly advances the doctrine  of multiple
proportion, with regard  to the successive
compounds of the  same   constituents. This
was likewise interwoven,  with  new and in-
genious views concerning gaseous and atomi-
cal  combination.   Mr. Iliggins having felt
himself aggrieved at seeing discoveries clear-
ly announced by him in 1789, brought for-  -j^"
ward nineteen years afterwards by Mr. Dal-
ton,  in his own name,  published  in  1814a  .^
book, entitled experiments and Observations''
on the Atomic Tbjpory and Electrical Phe-
nomena.  In this work he gives numerous
quotations from his Compm<,tivc View, which
abundantly establish his claim of priority to
the discovery of multiple proportions, and
the atomic theory of chemistry. It is no fault
of Mr. Iliggins, that his first work partook
of the  imperfect analyses of the day.  Indeed
we have reason, on the contrary, to be sur-
prised at his rejection  of many errors  then
sanctioned by high authority, and  his pro-
mulgation of many new truths, which might
appear, to contemporary writers, insulated,
or of little consequence, but to which subse-
quent  researches have  given a due place and
importance in the system of chemical know-
ledge.  Who would deny to Columbus the
glory of discovering a new world, merely be-
c. use the means of research placed within
his power, did not permit him to explore its
extensive coasts' Is not that glory on the con-
trary greatly enhanced, by the very early pe-
riod at which the discovery was achieved,
while  navigation as a science was still un-
known? 1  shall quote  a few passages, as he
gives  them, from  his  Comparative  View,
which  I th:nk are decisive in this fundamen-
tal discussion.
  " Hepatic gas (sulphuretted hydrogen), as
shall be shown, >s hydrogen in its full extent,
holding sulphur in  solution,"  This fact, of
hydrogen not changing its volume, by com-
bining with sulphur, has been marked among
the valuable discoveries of later times.
  "Therefore, 100 grains  of  sulphur,  re-
quire only 100 or 102  of the dry gravitating
matter of oxygen gas, to form sulphurous
acid.   As sulphurous acid gas  is very tittle
more than double the specific gravit) of oxy-
gen gas, we may conclude, that the ultimate
particles of snlphur and oxygen contain the 
                 EQU

same  quantity of matter; for oxygen gas
suffers no considerable diminution of its bulk,
by un.ting to the quantity of sulphur neces-
Sarv for  the f >rmation of sulphurous acid.
It contracts 1-llth as shall  be sho*'n here-
after."  Compare wi'h the above statement,
the following  from  Dr. Thomson's System,
published in 1807. « If this analysis be pre-
cise, it follows, that  100 cubic inches of hy-
drogen gas, in order to be converted into
sulphuretted hydrogen, combine with 7.69
grains of sulphur, and  are  converted into
about 26.6  cubic  inches; so  that hydrogen
gas, by dissolving sulphur, is  reduced to lit-
tle more than one-fourth of its original bulk."
Vol. i. p. 92.   Sir II. Davy has since proved,
by accurate  experiments, that hydrogen,  in
its conversion  into  sulphuretted hydrogen,
does not change its  bulk, agreeably to Mr.
Higgins's early  enunciation.  " But  as we
know the constituents of sulphuric acid, it
is  easy thence to deduce the following as
the proportion of the ingredients of sulphu-
rous acid:—•

               68 sulphur,
               32 oxygen.

              100"

System  of Chemistry, 1807, vol.  h. p. 179.
The last is the result of Dr. Thomson's own
experiments.  Its  true  composition  is now
known to be 100 of the gravitating matter of
oxygen to 100 of sulphur, in conformity with
Mr. Higgins.
   The elementary proposition  of Mr. Dal-
ton's atomical hypothesis, seems to be most
explicitly announced in the  following para-
graph of Mr.  Higgins.                  Jt.
   " As two cubic inches of hydrogen gas
require but one cubic inch of oxygen gas to
condense them to water, we may presume,
 that they contain an equal number of divi-
sions, and that the difference of the specific
 gravity of those gases depends on  the size of
 their  respective particles; or we  must sup-
 pose, that an  ultimate particle  of hydrogen
 requires two  or three or  more  particles of
 oxygen to  saturate  it.  Were this the case,
 water, or its constituents, might be obtained
 in an intermediate state of combination, like
 those of sulphur and oxygen, or azote and
 oxygen, &c.  This appears to be impossible;
 for in whatever proportion we mix hydrogen
 or ox_\ gen gases, or under whatever circum-
 stances we unite them, the result is invaria-
 b'y the same.   Water is formed,  and  the
 surplus of either of the gases is left behind
 unchanged,"—" From these circumstances,
 we have sufficient  reason to conclude, that
 water is composed  of a single ultimate par-
 ticle of oxygen, and an ultimate  particle of
 hydrogen, and that its atoms are incapable
                 EQU

of uniting lo a third particle of either of it*
constituents."                         .
  Mr. Higgins inculcates very strongly, that
when a body is capable of combining with
another in two proportions  the third parti-
cle  introduced is held bv a much weaker af-
finity than that which unites the particles of
the first or true binary compound.
  «In my opinion, the most perfect nitrous
acid contains 5 of oxygen and 1 of azote.—
Nitrous gas,  according to K.rwan,  contains
2 volumes of oxvgen  gas, and 1 of azotic
gas.  According to l-avoisi'T, liiO grains of
nitrous gas contain 32  grains of  azote,  and
68 of ox> gen.  1 am of the former philoso-
pher's opinion.  I also am of opinion,  that
everv  primary particle • f azote is united to
2  of oxygen",  and that  the mokcile  thus
formed, is surrounded  with one common at,
mosphere of caloric.
  " As this requires demonstration, let  A in
the  annexed diagram represent an ultimate
particle of azote, which attracts oxygen  with
the force of  3;
Let a be a particle of oxygen, whose attrac-
tion to A we will  suppose to be  3 more;
hence they  will unite with the force of 6;
the nature of this compound will  be here-
after explained   Let  us consider this to be
the utmost  force of attraction  that c.:-n  sub-
sist between  oxygen  and azote.   We  will
now suppose a second particle of oxygen b
to  combine with A; they will only unite  with
the force of 4$."   " This  I consider to be
the real stnicture of a molecule of nitrour Jfc-
gas.   Let a third particle"" ot" oxygen c unite'
[to  A  it will combine only with the force  of
4.  This is  the state of the red molecules of
 nitrous vapour, or when condensed, the red
nitrous acid."   " We  will suppose a fourth
 particle of  oxygen d to combine with A;  it
 will unite with  the force of 3J,  and so  on
 with the rest of the particles  ot oxygen as
 the diagram represents.  This I consider to
 be the state of  a molecule of the pale  or
 straw-coloured nitrous acid.
    " When a fifth particle of oxygen e unites,
 the force of union existing betwien the par-
 ticles of the molecule is still diminished as is
 represented by the diagram.   The fractions
 show  that the chemical attraction of azote
 for oxygen is nearly exhausted.  This is the
 state  of colourless nitrous acid; and, in my
 opinion, no more oxygen  can unite to the
 azote, having its whole force of  attraction
 expended in the particles a, b, c, d, e  This
 illustrates the nature of saturation or definite
 proportions."
    " We can readily perceive from the  fore-
 going demonstrations, that  oxygen is retain-
 ed with less force in the colourless nitrous 
                EQU

aaid tha» in the straw-coloured; and the lat-
ter acid retains  it with less force  than the
red nitrous acid; and nitrous gas  holds it
with still  more  force than the red nitrous
acid.  This accounts for the separation of
oxygen gas from the colourless nitrous acid
(nitric acid) when exposed to the sun, at the
same time that the acid becomes coloured.
Nitrous acid in any other state will afford no
oxygen, when exposed to the sun."
  " Why the  giseous oxide should  be more
soluble in  water than the nitrous gas, is what
1 cannot account for, unless it be occasioned
by  the smaller size  of its calorific atmos-
pheres, which may admit its atoms  to come
within the gravitating  influence  of  that
fluid."
  It is impossible to  deny the praise of sin-
gular ingenuity, and justness, to the above
passages; and every one must be struck with
their analogy, both as to atomical doctrines,
and the calorific atmospheres of gases, single
and compound, with the language and views
expanded at full length in Mr  Dalton's new
system of Chemical Philosophy, first framed
about the vear 1803, and published in 1808.
It appears that this philosopher, after medita-
ting on the definite proportions, in which oxy-
gen was shown by M. Proust to exist in the
two oxides of the same metal, on the suc-
cessive combinations of oxygen and azote,
and the proportions of various other chemi-
cal compounds, was finally led to conclude,
that the uniformity which obtains in corpus-
cular combinations, results from the circum-
stance, that they consist of one atom of the
one constituent, united generally with one
atom of the other, or  with two or three a-
toms.  Ana he further inferred, that the re-
lative weights of these ultimate atoms might
be ascertained from  the proportion of the
two constituents in a neutral compound.
  Chemistry is unquestionably under great
ebligations to Mr. Dalton, for the pains with
which  he collated  the various analyses of
chemical bodies, by different investigators;
and for establishing, in opposition to the
doctrine of indefinite affinity, taught by the
illustrious Bt-rthollet, that the different com-
pounds of the same principles did  not  pass
into each other by imperceptible gradations,
but proceeded, per saltum. in successive pro-
portions,  each a multiple of  the first.   By
correcting and extending Richter's scale of
reciprocal saturation, and reviving  Mr.  Hig-
gins's long neglected discovery of multiple
proportion,  Mr Dalton has been  no  mean
contributor to the advancement  of the  sci-
ence.  It  is difficult to say how far  his figur-
ed groups of spherical  atoms  have  been be-
neficial  or not.   They may have had some
use in aiding the conception of learners, and
perhaps in giving a novel and imposing air
to the atomical  fabric.   But  their arrange-
ment, and even their  existence,  are  alto-
                EQU

gether hypothetical, and therefore ought to  J
have no place in physical demonstrations.  J
  That water is a compound of an atom oi
oxygen and an atom  of hydrogen, is assum-
ed by Mr. Dalton as the basis of his system.
But two volumes of hydrogen here combine
with one  of oxygen. He therefore infers,
that an atom of  hydrogen  occupies double
the bulk, in its gaseous state, of an atom of
oxygen.  These assumptions are  obviously
gratuitous.  I agree with Dr. Pnuit in think-
ing that Sir H. Davy has taken a more phi-
losophical view of  this subject.  Guided by
the strict logic  of  chemistry, he  places  no
hypothesis at the foundation of his fabric.
  Experiment shows, 1st, That in equal vo-
lumes, ox>gen weigh 16 times more than hy-
drogen; and 2dly,  That water is formed  by
the union of one volume of the former, and
two volumes of  the latter gas, or by weight
of 8 to 1.   We are not in  the least authori-
zed to infer from this that an atom of oxy-
gen weighs 8 times as much as an atom of
hydrogen.  For aught we  know, water may]
be a compound of  2 atoms  of hydrogen, and \
1 of oxygen; in which case we should have  1
the proportion of the weights of the atoms, j
as given by equ-d volumes, namely, 1 to  16. >
There is no good reason for fixing on  one
compound ot hydrogen, more  than on  an-
other, in  the  determination of the basis of
the equivalent scale. If we deliberate on
that combination of hydrogen in which its
agency is apparently most energetic, name-
ly, that with chlorine, we would surely never
think of pitching on two volumes as its unity
or least proportion of combination; for it is
one volume of hydrogen which  unites with
one volume of  chlorine, producing two vo-
lumes of muriatic gas.  Here, therefore, we
see that one volume of hydrogen is quite ade-
quate to effect,  in  an active gaseous body of
equal bulk, and 36 times i's weight, an  en-
tire change of  properties.  Should  we as-
sume  in gaseous  chemistry, 2 volumes of
hydrogen, as the  combining unit, or as re-
presenting an  atom; then  it should never
unite in 3  volumes, or an atom and a half
with another gas.  Ammonia, however,  is a
compound of 3 volumes ofMiydrogen with 1
of azote; and if  2  volumes of hydrogen to 1
of oxygen be called an atom to an atom, sure-
ly  3  volumes of  hydrogen to  1 of azote
should be called  an atom and a  half to an
atom.  Vet the  Daltonian Commentator, on
the second occasion, counts one  volume an
atom of hydrogen, and on the first, two vo-
 lumes an atom.
   We would steer clear of all these gratui-
 tous assumptions and contradictions, by  ma-
 Sking a single volume of hydrogen represent
 its atom, or prime  equivalent.  " There is an
 advantage," says Dr. Prout, " in considering
 the volume of hydrogen equal to the atom,
 as, in this case, the specific  gravities of most, 
                EQU

or perhaps all elementary substances, (hy-
drogen being one,) will either exactly coin-
cide withjOrhe some multiple of the weights
of their atoms; whereas, if we make the vo
EQU
;\j
                                          singly, or if either is in excess, it exceeds hr
                                          a ratio to be expressed by some simple mul-
                                          tiple of the number of its atoms."
                                            It is evident from  this passage, that  the
lume  of oxvgen unity,  the weights of the  principle which presented itself to Mr. mi-
atoms of most elementary substances, except
oxygen, will be double that of their specific
gravities,  with  respect to hydrogen.  The
assumption of the volume of hydrogen, be-
ing equal to the atom, will also enable us to
find more readily, the specific gravities of
bodies in  their gaseous state, (either with  .
respect to hydrogen, or atmospheric air,) by  anticipation  of what  the advancement  ot
means of Dr. Wollaston's logometric scale,  analytical precision would infallibly have re-
    If the views  we  have ventured to ad-  vealed in a very short period.     I <j£ ^-y
                                                                          cisive
ton, on a review of the labours of other che-
mists, had really occurred to Dr. Wollaston
from his  own,  and that he  would  unques-
tionably have been speedily led to its full de-
velopement. If Mr. D.dton had ever chanced
to look into the neglected book  of  Higgins,
there would have been little merit  in his
                                            Dr. Wollaston, in the above  decisive pa-
                                          perTdemoristrates, that in the sub-carbonate
                                          and crystallized carbonate of  potash,  the
                                          relation of the carbonic acid to the base, in
                                          the first, is exactly one-half of  what it is in
                                          the second.  The same law is shown to hold
                                          with regard  to the two carbonates of soda,
                                          and the two sulphates of potash;  and being
                                          applied to his  experiments on  the com-
                                          pounds of potash and oxalic acid, leads him
                                          to conclude, that the neutral oxalate may be
                                          considered as consisting of 2 particles potash,
                                          with 1 acid; the binoxalate as 1 and 1, or 2 pot-
                                          ash, with 2 acid; the quadroxalate as 1 and 2,
                                          or 2 potash, with 4 acid.
                                             We cannot withhold from our readers the
                                          following masterly observations, which must
                                          make every  one regret,  that the  first de-
                                          velopement  of  the atomic  theory  had not
                                          fallen into such philosophical hands.
                                             " But an  explanation  which admits  a
                                          double  share of potash in the neutral s..lts,
                                          (the oxalates), is not altogether satisfactory;
primary combination, in his elements of che-, and I am farther inclined to think, that when
mical philosophy.                         f our views are sufficiently expended, to enable
  Mr. Dalton's  prelections on  the atomic.' us to reason with  precision concerning the
theory, and Dr. Thomson's commentary, had  proportions of elementary atoms, we  shall
excited but a feeble sensation in the chemi-  find the arithmetical relation alone  will not
cal world.  That part of his system  which  be sufficient to explain their mutual actional
treated on caloric, was blended with so much Jand that  we  shall be obliged iO acquire a\
mere hypothesis, that chemists transferred a ; geometrical conception of their relative ar- J
portion of the scepticism thus created, to his jj rangement,  in all the three dimensions of/
collation of primary and multiple combina- ^solid extension.
tions.  It was Dr. Wollaston  yvho first  de-     " For instance,  suppose the  limit to the
cided public  opinion in favour of the doc-  approach of particles, to be the same in all di-
vance be correct, we may almost consider the
neon u\» of the ancients to be realized in
hydrogen; an  opinion, by the byr, not alto-
gether new,  If we actually consider this to
be the case, and further consider the specific
gravities of bodies, in their gaseous state, to
represent the number of volumes condensed
into one; or in other words, the number of
the absolute weight of a single  volume of
the first matter (t^™  Sxn)  which they con-
tain, which is extremely probable; multiples
in weight must always indicate multiples in
volume, and vice versa; and the specific gra-
vities or  absolute weights ot all  bodies in a
gaseous state, must be multiples of the spe-
cific gravity, or absolute weight  of the first
matter,(*f«T>i uaw), because all bodies in a
gaseous state, which unite with one another,
unite with reference to their volume."
  From  these ingenious observations, we
perceive the singular felicity  of judgment,
with which Sir II. Davy made choice of the
single volume of  hydrogen, for  the unit of
trine of multiple proportions, by his elegant
paper on super-acid, and sub-acid salts, in-
serted  in the Philosophical Transactions for
1808.  The object of the atomic theory has
been no where so happily stated as by this
philosopher, in the following sentence:
  " But, since the  publication of Mr. Dal-
ton's theory of chemical combination, as ex-
plained and  illustrated by  Dr.  Thomson,
(System, 3d edit.),  the inquiry which 1 had
designed appears superfluous; as all the facts
1 had observed are  but particular instances
of the  more general observation of Mr. Dal-
ton, that in all cases the simple elements of
•odies are disposed to unite atom to atom
rections, and  hence their virtual extent to
be spherical, (which is the most simple hy-
pothesis); in this case, when different sorts
combine singly,  there  is  but  one mode of
union.  If they unite  in the  proportion of
two to one, the two particles will naturally
arrange themselves at opposite poles of that
to which they unite.   If they be three, they
might be arranged with  regularity  at the
angles of an equilateral triangle, in a great
circle surrounding the single  spherule; but
in this arrangement, for want of similar mat-
ter at the poles of this circle, the equilibrium
would be unstable, and would be liable to~
be  deranged by Hie slightest force of adja- 
EQU                                    EQU
oent combinations; but, when the number  ter at the poles of this circle, the equilibrium
of one set of particles exceeds in the propor-t  would be unstable, and would be liable to be
tion of 4 to 1, then, on the contrary, a stable  deranged by the slightest force of adjacent
equilibrium may again take place, it the four , combinations."   Compare with this remark
particles are situated  at the  angles of the'.,[ the following  sentence from my paper on
four equilateral triangles composing a regu-/ sulphuric acid, as  published in the Journal
lar tetrahedron.                            of Science, October, 1817.  « The terms of
  "But as this geometrical arrangement  of  dilution are, like logarithms, a series of num-
the primary elements of matter is altogether  bers in arithmetical progression, correspond-
                                          ing to another  series, namely, the specific
•onjectural,  and must rely for its confirma-
tion or rejection upon future inquiry, I am
desirous  that it should  not  be confounded
with the  results of the facts and observations
related above, which are sufficiently distinct
and satisfactory with respect to the existence
of the law  of simple multiples.  It  is per-
haps too  much to hope, that the geometrical \ a small addition of water or of acid to the
arrangement of primary particles will  ever  above atomic group, produces a great change
be  perfectly known; since,  even admitting //on  the  degree of condensation; which  ac-
that  a very  small number  of these atoms./cords with the position " that the equilibri-
combming together, would have a tendency  um would be liable to be deranged by the
gravities, in geometrical progression.  For a
little distance on both sides  of the  point of
greatest condensation, the series converges
with accelerated velocity, whence the 10 or
12 terms on either hand, deviate a little from
experiment." Page 126.  Or in other words,
to arrange themselves in the manner I have
imagined; yet until  it is ascertained  how
small a  proportion  the primary  particles
themselves bear to the interval  between
them, it  may be supposed that surrounding
combinations,although themselves analogous,
might disturb this arrangement;  and  in that
case, the effect of such interference must al-
so be taken into the account, before any the-
ory of chemical combination can be render-
ed complete."
   I am  not aware, that any  chemist has ad-
duced experimental evidence, to prove that
a "stable equilibrium may again take place,
if the four particles are  situated at the an-
gles of the four equilateral triangles compo-
sing a regular tetrahedron."  I have, there-
fore, much pleasure in referring to my re-
searches on the constitution of liquid nitric
acid, as unfolding a striking confirmation of
Dr.  Wollaston's true philosophy  of atomical
combination.  When I wrote the  following
sentence, I had no recollection whatever of
Dr.  Wollaston's  profound  speculations on
tetrahedral arrangement.—" We  perceive,
that the  liquid acid of 1.420, composed of 4
primes of water -f- 1 of dry acid, possesses
the greatest power of resisting the influence
of temperature to change its state.   It re-
quires the maximum heat to boil it, when it
distils unchanged; and the maximum cold to
effect its congelation." See  Acid (Nituic,)
m this Dictionary.
   Here  we have a fine  example of the sta-
bility of equilibrium, introduced  by the com-
bination of four atoms with one.  The disco-
very which I had also the  good fortune  to
make with regard to  the constitution of a-
queous sulphuric acid,  that the maximum
condensation occurred, when one atom of
the real acid was combined with three atoms
of water, is equally consonant to  Dr. Wollas-
ton's views.  "But in this arrangement,"
fays Dr. Wollaston, « for want of similar mat-
slightest force of adjacent combinations."
  While considering this part of Dr. Wollas-
ton's important paper, let me advert to the
curious facts pointed  out in the article Ni-
tric Acid, relative to the compound of one
atom of dry acid and seven atoms water.—
In my paper on the subject, published in the
eighth number of the Journal of Science, I
showed that this liquid combination  was ac-
companied with the greatest condensation of
volume, and  the greatest  disengagement of
heat.  In  composing this  Dictionary, I cal-
culated, for the first time,  the atomical con-
stitution of the nitric acids employed by Mr.
Cavendish, for congelation; and found with
great satisfaction, that the same proportion
which had exhibited, in my experiments, the
most intense reciprocal action, as was indi-
cated both by the aggregation of particles,
and production  of heat,  was likewise that
which most  favoured  solidification.   Such
acid congeals  at — 2°;  but when  either
stronger or weaker, it requires a much low-
er temperature for that effect.
  3. The  next capital discovery in multiple
proportions, was made by M. Gay-Lussac, in
1808, and published  by him in the second
volume of the Memoires d'Arcueil.  After de-
tailing a series of  fine experiments, he de-
duces the  following  important inferences;—~
" Thus it  evidently appears,  that all gases,
in their mutual action, uniformly combine
in the most simple proportions; ;«nd we have
seen, in fact, in all the preceding examples,
that the ratio of their union is that of 1 to 1,
of 1 to 2; or of 1 to  3, by volume.  It is im-
portant to observe, that when we consider
the weights,, there is no simple and definite
relation  between the elements of a first com-
bination; it is only when there is a  second
between these same  elements, that the new
proportion of that body which has been ad-
ded, is a multiple of the first.  Gases, on the
contrary,'in  such ~ proportions as can coin- 
EQU                                  EQU
 bine, give rise always to compounds, whose
 elements are, in volume, multiples the one
 of the other.
   " Not only do the gases combine in very
 simple proportions, as we have just seen,
 but moreover,  the apparent contraction of
 volume which they experience by combina-
 tion, has likewise a simple relation  with the
 volume of the  gases, or rather with the vo-
 lume of one of them."
   By supposing  the contraction  of volume
 of the two gaseous constituents  of  water to
 be only equal to the whole volume of oxy-
 gen added, he found the ratio of the densi-
 ty of steam to be to that of air as 10 to 16; a
 computed result  in  exact  correspondence
 with the experimental result lately  obtained
 in an independent method, by the same ex-
 cellent philosopher.  " Ammoniacal gas is
 composed in volume," says he, "of 3 parts
 of hydrogen and  1 of azote, and its density,
 compared to that of air, is 0 596; but if we
 suppose the apparent contraction to be one-
 half of the total volume, we find 0.594 for its
 density.   Thus it is  demonstrated by this
 nearly perfect accordance, that the apparent
 contraction of its elements is precisely one-
 half of the total  volume or rather double the
 volume of  azote."  M. Ga\-Lussac  subjoins
 to his beautiful memoir a table  of  gaseous
 combination, which, with some modifications
 derived from subsequent researches, will be
 inserted under the  article Gas.
   The same volume of the JMemoires pre-
 sents another important discovery of M. Gay-
 Lussac, on  the  subject of equivalent pro-
 portions.   It is  entitled, On the  relation
 which exists between  the oxidation of me-
 tals, and  their capacity of saturation for the
 acids.  He here  proves, by a series of ex-
 periments, that the quantity of acid which
 the different metallic oxides require for sa-
 turation, is in the direct ratio of the quanti-
 ty of oxygen, which they respectively con-
 tain.  "I  have  arrived at this principle,"
 says  he, " not  by  the comparison  of the
 known  proportions of the  metallic salts,
 which are in general too inexact to enable
 us to recognize this law, but by  observing
 the mutual precipitation of the metals, from
 their solutions in  acids."
   When we precipitate a solution of acetate
 of lead, by a plate of zinc, there is formed a
beautiful vegetation known under the name
 of the tree of Saturn; and which arises from
 the reduction of the lead by a galvanic pro-
 cess,  as was first shewn  by Silvester and
 Grotthus.  We obtain at the same time a so-
 lution of  acetate of zinc, equally  neutral
 with that of the lead,  and entirely  exempt
 from  this last metal.   No hydrogen, or al-
 most none, is disengaged during the preci-
 pitation; which proves, that the whole oxy-
 gen necessary to the zinc, for its becoming
 dissolved and saturating the acid, lias been
 furnished to it by the lrad.
    If we put into a  solution of sulphate of
 copper, slightly acidulous, bright iron turn-
 ings in excess, the copper is almost instant-
 ly precipitated; the  temperature rises, and
 no gas is disengaged. The sulphate of iron
 which we obtain, is that in which the oxide
 is at a minimum, and its acidity is exactly
 the same as that of  the sulphate of copper
 employed.
    We obtain similar results, by decomposing
 the acetate  of copper  by lead, especially
 with the aid of heat.  But  since  the  zinc
 precipitates the lead from its acetic solution,
 we may conclude, that it would also precipi-
 tate copper, from  its combination with the
 acetic acid.  Experience is  here in perfect
 accordance with theory.
    We know with what facility copper pre-
 cipitates silver, from its nitric solution.  All
 the oxygen winch it  needs for its solution,
 is furnished to it by the  oxide of silver; for
 no gas is disengaged, and the acidity is un-
 changed. The same thing happens with cop.
 per, in regard to nitrate of mercury and to
 cobalt, in regard to  nitrate of silver.  In
 these last examples, as in the preceding, the
 precipitating metd, finds in the oxide of the
 metal, which it precipitates,  all the oxygen
 which is necessary to it for its oxidizement,
 and for neutralizing to the same degree the
 acid of the solution.
   These  incontestable facts  naturally con-
 duct to the principle announced above, that
 the acid in the metallic salts, is directly pro-
 portional to the oxygen in their oxides.  In
 the precipitation of one metal  by another,
 the quantity of oxygen in each oxide remains
 the same, and consequently the larger dose
 of oxygen the precipitating metal takes, the
 less metal will it precipitate.
   M. Gay-Lussac next proceeds to show.
 with regard to the same metals at their dif-
 ferent stages of oxidizement, that they re-
 quire of acid, a quantity precisely propor-
 tional to the quantity of oxygen they  may
 contain;  or that the acid in the salts, is ex-
 actly proportional to the oxygen of the ox-
 ides.  A very important result of this law,
 is  the ready  means it affords of determin-
 ing the proportions of all the metallic salts.
 The proportions of one metallic  salt, and
 the oxidation of the  metals, being given,
 we may determine those of all the salts of
 the same genus; or the proportions of acid,
and of oxide, of all the metallic salts; and
the oxidation of a single metal being given,
 we can calculate the oxidation of  all the
rest.  Since  the peroxides  require most
 acid, we can easily  understand  how the
salts containing them, should be in general
more soluble than those with the protoxide. 
                  EQU

   M. Gay-Lussac concludes his memoir
 with this  observation.   When  we  preci-
 pitate a metallic solution, by  sulphuret-
 ted hydrogen, either alone  or combined
 with an alkaline base, we obtain a sulphu-
 ret  or a metallic  hydrosulphuret.  In the
 first case,  the hydrogen of the sulphuret-
 ted  hydrogen combines with all the oxygen
 of the oxide, and the sulphur forms a sul-
 phuret with the metal; in the second case,
 the  sulphuretted hydrogen  combines di-
 rectly with the oxide, without  being de-
 composed, and its proportion is  such, that
 there is sufficient hydrogen to saturate all
 the  oxygen of the oxide.  The quantity of
 hydrogen neutralized, or capable of being
 so, depends therefore on the oxidation of
 the  metal, as well as  the  quantity of the
 sulphur, which can combine with it.  Of
 consequence, the same metal forms as many
 distinct sulphurets, as it is susceptible of
 distinct stages of oxidation in its  acid so-
 lutions.  And as  these degrees of oxida-
 tion are fixed, we may also obtain sulphu-
 rets, of definite proportions, which we can
 easily determine, according to the quanti-
 ty of oxygen to each metal,  and the pro-
 portions of sulphuretted hydrogen.
   The next chemist who contributed essen-
 tially to the improvement of the equiva-
 lent ratios  of chemical bodies, was Berze-
 lius. By an astonishing number of analy-
 ses, executed for the  most part with re-
 markable precision, he enabled  chemical
 philosophers to fix with corresponding ac-
 curacy, the equivalent ratios reduced to
 their lowest terms.  He himself took oxy-
 gen as the unit of proportion.
   The results of all this emulous cultiva-
 tion, were  combined and illustrated  with
 original researches, by Sir H. Davy, in his
 Elements of Chemical Philosophy publish-
 ed in 1812.  In this system of truths, which
 will never become obsolete, we find  the
 claims of Mr. Higgins to the discovery of
 the atomic theory justly advocated.
   But what peculiarly characterizes this
 chemical work, is the sound antihypotheti-
 cal doctrines which it inculcates on chemi-
 cal combination.  "Mr. Higgins," says Sir
 H. " has supposed that water is composed
 of one particle of oxygen and  one of hy-
 drogen, and  Mr. Dalton of an atom  each;
 but in the doctrine of proportions derived
 from facts, it is not necessary to consider
 the combining bodies, either as composed
 of indivisible particles, or even as always
 united, one and one, or one  and  two, or
 one and three proportions,   Cases will be
 hereafter pointed out, in which the ratios
 are very different; and at present, as we
have no means whatever of judging either
of the relative numbers, figures, or weights,
of those particles of bodies  which are not
in contact, our   numerical  expressions
   Vol.  1L
                EQU

 ought to relate only to the results of ex-
 periments."
   He conceives that the calculations will
 be much expedited, and the formulae ren-
 dered more simple,  by  considering the
 smallest proportion of any  combining body,
 namely, that of hydrogen, as the integer.
 This radical proportion of hydrogen, is the
 5rg«T» i'hti of the ancient philosophers.
   It has been objected by some, to our as-
 suming hydrogen as the unit, that the num-
 bers representing the metals,  would be-
 come inconveniently large.  But this could
 never be  urged by any person  acquainted
 with the theory of numbers.  For in what
 respect is it more convenient to reckon ba-
 rium 875 on the atomic scale,  or 8.75 X
 16 = 140 on Sir  H. Davy's scale of expe-
 riment? or is it any advantage to  name,
 with Dr. Thomson, tin =  7.375, or to call
 it 118, on the plan of  the  English philoso-
 pher?  If the combining ratios of all bo-
 dies be  multiples of hydrogen, as is proba-
 ble,  why not take hydrogen  as the unitJ
 I think this question will not be answered
 in the negative, by those who practise the
 reduction of chemical proportions.    The
 defenders of the Daltonian hypothesis, that
 water consists of one  atom oxygen to one
 atom hydrogen,  may refer to Dr. Wollas-
 ton's scale, as authority for taking oxygen
 as the unit. But that admirable instru-
 ment, which has at once subjected thou-
 sands of chemical combinations to all the
 despatch  and precision of logometric cal-
 culation, is actually better- adapted  to the
 hydrogen  unit, than to the oxygen.  For if
 we slide down the middle rule,  till 10 on it
 stand opposite to 10 hydrogen on the left
 side, every thing on the scale is given in
 accordance with  Sir H. Davy's system of
 primary proportions, and M. Gay-Lussac's
 theory of  gaseous combination.  This va-
 luable concurrence, as is well pointed out
 by Dr. Front, we lose, by  adopting the vo-
 lume of oxygen as radix.
   In the first part of the Phil.  Trans, for
 1814, appeared Dr. Wollaston's description
 of his scale of chemical equivalents, an in-
 strument which has contributed  more to fa-
 cilitate the general study  and practice of
 chemistry than any other invention of man.
 His paper is further valuable, in  presenting
 a series of numbers denoting the relative
 primary proportions,  or  weights of the
 atoms of  the principal CliernicaT""bodies,
 both  simple and compound, determined
 with singular sagacity, from a general re-
view of the most exact analyses of other
chemists, as well as his own.
  The list  of substances which he has esti-
mated, is  arranged on one or other side
of a scale of numbers, in the order of their
relative  weights,  and at  such  distances
from each other, according to their weights,
                       o 
                 EQU

that the series of numbers placed on a slid-
ing scale can at pleasure be moved, so that
any  number expressing the weight of a
compound, may be brought to correspond
with the place of that  compound, in the
adjacent column.  The arrangement is then
such, that the weight of any ingredient in
its composition, of any  reagent to be em-
ployed, or precipitate that might be obtain-
ed in its analysis,  will be  found  opposite
the point, at which its respective name is
placed.
  If the slider be  drawn upwards, till 100
corresponds to muriate of soda, the scale
will  then  show how much  of each sub-
stance  contained in the table, is equivalent
to 100 of common salt.   It shows, with
regard to  the different views of this salt,
that it  contains 46.6 dry muriatic acid, and
53.4 of soda, or 39.8 sodium, and 13.6 oxy-
gen; or if viewed as chloride of sodium,
that it  contains  602 chlorine and 39.8 so-
dium.  With respect to reagents, it may
be seen, that 283 nitrate of lead, contain-
ing 191 of litharge, employed to  separate
the muriatic acid, would yield a  precipi-
tate of 237 muriate of lead, and that there
would  then remain in solution, nearly 146
nitrate of soda.  It may at the  same time
be seen; that the  acid in this quantity  of
salt, would serve to make 232 corrosive
sublimate, containing 185.5  red  oxide  of
mercury; or make 91.5 muriate of ammo-
nia, composed of  62 muriatic gas (or hy-
dromuriatic acid),  and  29.5  ammonia.
The scale shows also, that for the purpose
of obtaining the whole of the acid in dis-
tillation,  the quantity of oil of vitriol re-
quired is nearly 84, and that the residuum
of this distillation would be 122 dry sul-
phate of soda, from  which might be ob-
tained, by crystallization, 277 of glauber
salt, containing 155 water of crystallization.
These, and many  more such answers, ap-
pear at once, by bare inspection,  as soon
as the weight of any substance  intended
for examination is made, by motion  of the
slider, correctly  to correspond  with  its
place in the adjacent column.  Now surely
the accurate and  immediate solution of so
many  important practical problems, is an
incalculable benefit conferred on  the che-
mist.
   With  regard to the method  of  laying
down  the divisions of this scale, those who
 are accustomed to the use of other sliding
 rules,  and are practically  acquainted with
 their properties,  will recognize  upon the
 slider itself, the common  Gunter's  line of
 numbers, (as it is called), and will be satis-
 fied, that the results which it gives are the
 same  that would  be obtained by arithmeti-
 cal computation.
   Those who are acquainted with the doc-
 trine  of ratios, and  with  the use of loga-
 rithms as measures of ratios, will  under-
               EQU

stand the principle on which this scale  is
founded, and will not need to bo told, that
all  the divisions are  logometric; conse-
quently, that the mechanical addition and
subtraction  of ratios here performed by
juxtaposition, corresponds in effect to the
multiplication and division of the numbers,
by which those ratios are expressed in com-
mon arithmetical notation.
  In his Essay on the cause of Chemical
Proportions, Berzelius proposed a system
of signs, to  denote atomical combinations,
which it may be proper briefly to explain.
This sign is the initial letter, and by itself
always  expresses one atom,  volume,  or
prime of the substance.  W hen it is ne-
cessary to  indicate several  volumes  or
primes, it is done by prefixing the number;
for example, the cuprous oxide, or protox-
ide of copper, is composed of a prime  of
oxygen and  a prime of metal; its  sign  is
therefore Cu -f- O. The cupric oxide,  or
deutoxide of copper,  is composed  of 1
prime metal, and 2 primes oxygen; there-
fore its sign is Cu -+- 20.   In  like manner
the sign for sulphuric acid is S -f- 30; for
carbonic acid, C -f- 20; for water, 2H  -f-
O, &c.
  When we express a compound prime of
the first order, or binary, we  throw away
the -j-, and  place the number  of primes
above the letter, as the index or exponent
is placed in  arithmetic.  For example, CuO
-L.  SO3 =  sulphate of copper; CuO2  -f
2S03  = bi-deutosulphate of copper,  or
persulphate.   These  formulae  have this
advantage,  that if we take away the oxy-
gen, we see at once the ratio  between the
radicals.  As to  the primes of the second
order, or ternary compounds, it is but rare-
ly of any advantage to express them by for-
mulae, as one prime; but if we wish to ex-
press them  in that way, we may do it by
using the  parenthesis, as is  done  in  al-
gebraic formulae; for example, according to
Berzelius, alum is composed of 3 primes
of sulphate  of alumina, and 1 of sulphate
of  potash.   1's  symbol is 3(AlO+S03)
+  (PoO-f-SO3).  The prime  of ammonia
is 3 HN; viz. 3 primes hydrogen -f- 1 nitro-
gen.   We  shall use these abbreviations in
our table of equivalent primes, at the end
of the volume.
   To reduce analytical results, as usually
 given for 100 parts, to the equivalent prime
ratios, or, in hypothetical language,  to the
 atomic proportions, is now a problem of
 perpetual recurrence, with which students
 are perplexed, as no  rule  has been given
 for its ready solution.  Though numerous
 examples of its solution occur in this Dic-
 tionary, we shall here explain it in detail.
   As in all reasoning we must proceed from
 what is known or  determinate, to what is
 unknown or indeterminate, so in every ana-
 lysis, there must be one ingredient whose 
EQU                                EQU
 prime equivalent is well ascertained. This
 is employed as the common  measure, and
 the proportions of the rest are compared
 to  it.  Let us take,  for instance,  Sir II.
 Davy's  analysis of fluate of lime, to deter-
 mine the unknown number, that should de-
 note the prime of fluoric acid.  We know,
 first of  all, that 2 primes  of oxygen = 2,
 combine with 1 of carbon = 0.75, to form
 the compound prime 2.75 of carbonic acid.
 We likewise know that carbonate of lime
 consists of 43.6 carbonic acid -+- 54.4 lime.
 We therefore make this proportion, to de-
 termine the prime equivalent of lime.
  1.  43.6 : 54.4 :: 2.75 : 3.56 =  prime of
 lime.
  2. We know that 100 parts  of dry sul-
 phate of  lime, consist of 41.6 lime and
 58.4 acid.  Hence, to find the prime of sul-
 phuric acid, we make this proportion:
  41.6: 58.4:: 3.56 : 5 = prime  of sulphu-
 ric acid.
  3. Sir H. Davy  obtained from 100  grains
 of fluor spar  in powder, acted on with re-
 peated  quantities of sulphuric acid, and
 ignited, 175.2 grains of sulphate of lime.
 Now, since 100 grains of sulphate of lime
 contain, as above, 41.6 of  lime, we have
 this proportion:
  100 : 41.6:: 1752:72.88 =  lime, corres-
 ponding to 175.2 grains of sulphate,  and
 which previously existed in the 100 gr. of
 fluor spar. If from 100 we subtract  72.88,
 the difference 27.12 is the  fluoric acid, or
 the other ingredient of the  fluor, which sa-
 turated the lime.  Now to find its  prime
 equivalent, we sav,
  72.88  : 3.56 :: 27.12 :1.325 =  the  prime
 or atom of fluoric acid from Sir H. Davy's
experiment.  Had we taken Dr. Thomson's
number 3.625, as  representing the atom of
lime, the atom of fluoric acid would come
out 1.3015.  As the Doctor had a particu-
lar  hypothesis to support, which required
the weight of the acid atom to be a great
deal less, he  deduces it, from the same
data,  to be only 1.0095.   By  what new
process of arithmetic  he brought out this
number, it  is  impossible to  conjecture.
But no doubt he devoted some pains to the
computation, since he  rears on that unsub-
stantial basis, a long  fabric of atomic in-
duction.
  We shall give another example, derived
from a more complex  subject.
  M.  Vauquelin found, that  33 parts of
lime, saturated with sorbic acid, and care-
fully dried, weighed  100 grains.  Hence
the difference, 67  grains, was  acid.  To
find its equivalent prime, we say,
  As  33 : 67 :: 3.56 = the prime  of lime
:7.23  = the prime of  the acid.  But as he
brought it to absolute  neutrality by a small
portion of potash, we may take 7.5 for the
prime.
  M.  Vauquelin subjected the acid, as it
exists in the dry sorbates of lead and cop-
per, to igneous analysis; and obtained  the
following results:
           Hydrogen,    16.8
           Carbon,       28.3
           Oxygen,       54.9
                        100.0
  Now we must find such an assemblage
of the primes or atoms of these elements,
as will form a sum-total of 7.5; and at the
same time be to each  other, in the above
proportions.  The following very  simple
rule will give a ready approximation;  and
by a common sliding scale, it may be work-
ed by inspection.
  Multiply each proportion per  cent, by
the compound prime,  and  compare  the
products with the multiples of the consti-
tuent primes.  You can then estimate the
number  of each prime requisite to compose
the whole. Thus,
0.168 X 7.5 =. 1.2600 or 10 hydrogen = 1.25
0.283 X 7.5 = 2.1225    3 carbon   = 2.25
0.549 X 7.5 = 4.1175    4 oxvgen   = 4.00
Theory.	Experiment
16.7	16.8
30.0	28.3
53.3	54.9
7.50   100.0    100.0
  The differences between these theoreti-
cal and experimental proportions, are pro-
bably within the limits of the errors of the
latter in the present state of analysis.
  If on Dr. Wollaston's scale we mark with
a type or a pen,  2h,  3h, &c. up to 10h;
2c, 3c, 4c, 5c;  and 2n, 3n, 4n; respectively
opposite  to twice, thrice, &c. the atoms of
hydrogen, carbon, and nitrogen, as is  al-
ready done for oxygen, (with the excep-
tion of the fourth, where copper stands),
we shall then  have ready approximations
to the prime components, by  inspection of
the scale.  Move the sliding part, so that
one of the quantities per cent, may stand
opposite the nearest estimate of a multiple
prime of that constituent.  Thus we know
that hydrogen, carbon,  and  oxygen, bear
the relation to each other of 1, 6, 8; and,
of course,  the latter two, tb;it of  3 to 4.
But 54.9 oxygen, being more than one half
of 100, the  weight of oxygen in the com-
pound  prime is more than the half of 7'.5,
and therefore points  to 4.  Place 54.9 op-
posite 4 oxygen,  (where copper stands),
we shall find  ltf  opposite 10  hydrogen,
and  30.7  opposite 3 carbon.  Here we
see the proportions of carbon  and  hy- 
                 EQU

drogen,  are  both greater than by Vau-
quelin's analysis.  Try 51 opposite 4 oxy-
gen, then opposite 3 carbon we have, 28.7,
and  opposite 10 hydrogen 16.9.  The pro-
portions  I  have  calculated  arithmetical-
ly above, seem somewhat better approxi-
mations;  they  were  deduced from  hydro-
gen  0.125, 'and  carbon  0.75, instead of
0.132 and0754, as on the scale.
  If the weight of the compound prime is
not given, then we must proceed to estimate
the nearest prime proportions, after inspec-
tion  of iiose per cent.   The scale may be
used with advantage, as just now explained.
  The followingcase has been reckoned dif-
ficult of solution, and has been even involved
in an algebraic formula.   Let us suppose a
vegetable acid, containing combined water,
whose  prime  equivalent  is to be  deter-
mined by experiment.  A crystallized salt
is made with it, for example, and a deter-
minate quantity of soda.   Suppose the al-
kali  to form 26 per cent of the salt.  The
rest  is water and acid. Dissolve 100 grains,
and  add  them to an indefinite quantity of
the solution of any  salt,  with  whose base
the vegetable acid forms an insoluble com-
pound.  Dry  and weigh  this  precipitate.
Without  decomposing the latter, we have
sufficient data for determining the  prime
equivalent of the real acid.  We make this
proportion: As the weight of soda is to its
prime equivalent, so is  the weight of the
precipitate, to the prime of the compound.
Suppose  148 grains of an insoluble salt of
lead to have been obtained; then 26:3.95 ::
148:22.1 = the prime of the salt of lead.
From this, if we deduct the weight of the
prime equivalent of  oxide of  lead, =  14,
we have 8.1 for the prime equivalent of the
acid.  And the crystallized salt must have
consisted of,
             Dry acid, 53.3
             Soda,     26.0
             Water,   20.7
                     100.0
  As  the  above numbers  were assumed
merely for arithmetical illustration, the wa-
ter is  not atomically expressed.  Indeed
the problem of finding the acid prime, does
not require the salt to be either dried or
weighed.   A solution would  suffice.  Sa-
turate a known weight of alkali, with an
unknown quantity of the crystallized acid.
Add this  neutral solution,  to a redundant
quantity of solution  of nitrate  of  lead.
Wash, dry, and weigh  the insoluble pre-
cipitate, and apply the above rule.
  There are three systems of equivalent
numbers at present  employed:  1st,  That
having oxygen as the radix; 2d, That hav-
ing one volume of hydrogen, as the radix;
3d, That having two volumes of hydrogen
Cas the radix, on the Daltonian  supposition,
that two volumes of hydrogen contain the
               ETH

same number of atoms, as  one volume of
oxygen." As this hypothesis is destitute of
proof, it evidently should be discarded from
physical science. Since the volumeof hydro-
gen is equal in weight to l-16th the weight
of the volume of oxygen, the former two
systems are mutually convertible, by multi-
plying the number  oxygen, in the oxygen
ratio, by 16, or 4 X 4, to obtain the number
in the hydrogen scale; and this is re-conver-
ted by the inverse operation, namely, divi-
ding by 16, or by 4  X 4.
  Dr. Wollaston's scale, and Sir H Davy's
proportional numbers,  are adapted to  the
idea that water is a compound of 1 hydro-
gen + 7.5 oxygen by weight, or 15 + 1 by
volume. Their mutual  conversion is there-
fore very easy, for if we add to Dr. Wollas-
ton's number, its half, the sum is Sir H.
Davy's;  and of course,  if we subtract from
the number of the latter, its third, the  re-
mainder is Dr. Wollaston's number. There
is one very frequent variation in the weights
of the  primes among  the best writers,
namely, doubling or halving the number.
This difference is occasioned generally by
an uncertainty about the first term or pro-
portion  in which the body combines with
oxygen; some chemists  reckoning that a
protoxide which others consider a deutox-
ide.   Thus Sir  H.  Davy gives 103 as  the
number representing iron; from which, if
we deduct ^-§-^ = 34.3, the remainder 68.7
is nearly double of 34.5, the number of Dr.
Wollaston.  But Mr. Porrett has  very in-
geniously shown that perhaps —~ = 17.5,
is to be preferred.*
  Essences.  Several of  the  volatile or
essential oils  are  called essences by  the
perfumers.
  Ether.  A very volatile fluid, produced
by the distillation of alcohol with an acid.
  When strong sulphuric acid is poured
upon an equal weight of alcohol, the fluids
unite with a hissing noise and the produc-
tion of heat, at the same  time that a  fra-
grant vegetable smell is perceived, resem-
bling that of apples. It is much better and
safer, however, to  add the acid by small
portions at a time,  at such intervals as that
no perceptible heat may be produced. The
mixture may be made in a glass retort, and
the  distillation performed  by regulated
heat on a sand-bath, a large tubulated re-
ceiver being previously well  adapted,  and
kept cool by immersion in water, or  the
frequent application of wet cloths.  A bent
glass tube luted to the tubulure of the re-
ceiver,  and having  its extremity immersed
in a little water or  mercury,  will allow the
gases to escape, and confine the condensi-
ble vapour.  The first product is a fragrant
spirit of wine,  which is followed by  the
ether, as soon as the fluid  in the retort be-
| gins to  boil.  At this period, the upper  part 
ETH                                 ETH
of the receiver is covered with  large dis-
tinct streams of the fluid which run down
its sides.  After the ether has passed over,
sulphurous acid arises, which is known by
its white fume and peculiar smell.  At this
period the receiver must be unluted and
removed, care being taken to avoid breath-
ing the penetrating fumes of the acid; and
the fire must at the same time be modera-
ted, because the residue in  the retort is
disposed  to  swell.  A light yellow  oil,
called sweet oil of wine, comes  over after
the ether, and is succeeded by black and
foul sulphuric acid.  The residue varies in
its properties according to the management
of the heat.  If the fire be much increased
toward the end of the process, the sulphu-
rous  acid that comes  over, will be mixed
with vinegar.
  The ether comes over mixed with alco-
hoi  and  some sulphurous  acid.  It was
usual to add some distilled water to this
product, which occasioned the ether to rise
to the top.  Rectification is absolutely ne-
cessary, if the ether have a sulphurous
smell; and this is indeed the better method
in all cases, because the water added in the
old method always absorbs about one-tenth
part of its weight of ether, which cannot
be recovered without  having  recourse to
distillation; and also because the ether is
found to absorb a quantity of the water.
Previous to the rectification, a small quan-
tity of black oxide of manganese should be
added, shaking the mixture occasionally
during 24  hours.  Proust  prefers  clean
slaked lime, as recommended by Woulfe;
observing that the bottle must not be above
three parts filled, and that it must be moved
about in cold water for some minutes be-
fore the cork is taken out.
  The inexperienced chemist must be re-
minded, that the extreme inflammability of
alcohol, and still more of ether; the dan-
ger of explosion which attends the sudden
mixture and agitation of concentrated acids
and alcohol;  and the suffocating effect of
the  elastic fluids,  which  might  fill  the
apartment if inadvertently disengaged; are
all  circumstances which require cautious
management.
  Sulphuric ether is a  very fragrant, light,
and volatile fluid.  Its  evaporation  pro-
duces extreme  cold.  It is highly inflamma-
ble, burns with a more  luminous flame than
alcohol, which  is of a deep blue, and emits
more smoke.   At  46°  below 0 of  Fahr. it
becomes solid.  It dissolves essential oils
and resins, and camphor very plentifully.
By  long digestion  it  dissolves l-13th  of
sulphur in the light, and l-17th in the dark.
This  preparation Mr.  Favre recommends
as an  excellent test of  lead in wine, which
it throws down  in a  black precipitate.
Mixed with  the muriatic solution of gold,
it retains a portion of the metal in solution
for some time.
   * To give ether its utmost  purity, we
must add to  the common purified ether, dry
subcarbonate of potash in powder, till the
last portions are not wetted, and draw off
the ether by distillation.  Its sp. gr.  will
fall from 0.775 to 0.746.  Being thus de-
prived of its water,  it must next be freed
from alcohol, by digesting it on dry muriate
of lime, and decanting the supernatant li-
quid, which is ether of sp. gr. 0.632 at 60°,
according to Lowitz. Distillation increases
its density to 0.7155 at 68°,  according to
M. T. de Saussure.
   Ether boils in the atmosphere at  98° F.
and  in vacuo at — 20°.   The density of its
vapour as determined by M. Gay-Lussac, is-
2.586, that of air being 1. Ether admitted
to any gas standing  over mercury, doubles
its bulk at  atmospheric  temperatures.  If
oxygen be thus expanded with ether, and
then mixed with three times its bulk of
pure oxygen, on being kindled it explodes,
forming carbonic acid and water.  By de-
tonating such a mixture  M. de Saussure
has lately inferred ether to consist of
           Hydrogen,    14.40
           Carbon,     67.98
           Oxygen,     17.62
                      100.00
  These proportions per cent, correspond
to       Olefiant gas,  80.05
         Water,       19.95

                      100.00
Or very nearly 5 primes olefiant  gas, con-
sisting of 5 carbon -J- 5 hydrogen-
  Or  (0.750-f 0.125) X 5  = 4.375
  1 prime water, or 1 hy-") —
    drogen -f- 1 oxygen, 5    1-1"J5
                             5.500
  Or 6 hydrogen + 5 carbon -j- 1 oxygen.
  By passing ether through a red-hot por-
celain tube, it is resolved into  heavy  in-
flammable air, a viscid volatile oil, a little
concrete oil, and charcoal and water.
  Ten parts of water combine with one of
ether.   Sulphuric acid  converts ether into
syveet oil of wine.   If a very little ether be
thrown into a large bottle filled with chlo-
rine, a white vapour soon rises, followed by
explosion and flame.   Charcoal is depo-
sited, and carbonic acid gas formed.
  If we apply to ether that principle of re-
search invented by M. Gay-Lussac, and so
successfully applied by him to iodine and
prussic acid, we shall find that,        **' 
ETH                                ETH
2 volumes of defiant gas,
1    do.    vapour of water,
= 0.9722 X 2 = 1.9444
              = 0.6249
Condensed into one volume of vapour of ether
Which is very nearly the experimental  sp. gr.
= 2.5693
= 2.5860
  On this view, the vapour of ether con-  of aqueous vapour consists of one volume of
tains one-half of the combined water, that  hydrogen,  and half a volume  of oxygen.
the vapour of alcohol does.                Hence the ratio of the weights  of the con-
  But two volumes of defiant gas consist of  stituents will become, on  the hypothetical
four volumes of hydrogen, and four of car-  oxygen scale, in which half a volume of
bon, in a condensed state; and one volume  oxygen represents one atom,
                 5 atoms hydrogen, = 0.125 X 5 = 0.625 ... 13.513
                 4       carbon,   = 0.750 X 4 = 3.000 ... 21.622
                 1       oxygen,   = 1.000 X 1 = 1.000 ... 64.865
  These proportions differ from those of
M. de Saussure, in  making  the carbon a
little more, and the oxygen a little less,
than he found.
  Ethers, exactly the same with the sulphu-
ric,  may be  obtained  by passing alcohol
through phosphoric and arsenic acids con-
centrated and heated.
  Another  kind of ethers are those which
result from the combination of the alcohol
with the acid  employed to  make  them.
Nine  such  ethers  are  known.  Muriatic
ether, nitric ether, hydriodic ether, acetic
ether,  benzoic  ether,  oxalic  ether, citric
ether, tartaric ether, gallic ether; the first
four are more  volatile than alcohol; the
rest are much less so,  for they boil with
more difficulty than water.
  Muriatic ether.  It is formed by saturat-
ing alcohol with muriatic acid gas; or still
better by mixing together equal  bulks of
alcohol and concentrated liquid  muriatic
acid, and heating the mixture in a glass re-
tort connected with a Woulfe's apparatus.
The first bottle should contain  a quantity
of water, at about 80° F.; the second should
be surrounded with ice.  From 10 ounces
of acid, and  an equal  bulk of alcohol, 1.2
ounces of ether may be obtained.
  Under the barometric  pressure  of 30
inches, this ether is always gaseous at 51°,
and all higher temperatures.   In the state
of gas it is colourless,  and without action
on  litmus,  or violets.   Its odour is  very
strong and analogous to that of sulphuric
ether;  its taste  is perceptibly saccharine;
and its sp. gr. compared to  that of air is
2-219.
  In the liquid state at 40° F., its sp. gr. is
0.874.   Poured on the  palm of the hand, it
immediately  boils, and produces  much
cold.  At a dull red heat, muriatic ether is
converted into muriatic acid gas, and de-
fiant gas, with, most probably, water; for
M. Thenard gave for its composition, from
the mean of  many  eudiometric, and other
experiments, acid 29.48 -+- carbon 36.6 -f-
oxygen 23.28 + hydrogen 10.64 =  100.—
         4.625   100.000
Mem. cCArcueil, i. 343.  Eight years there-
after, he modified these results  into 46.5
acid + 53.5 alcohol, (32.6 olef. gas + 20.9
water).—Traiti, Hi. 977.
  According to MM.  Colin and Robiquet,
(Annates de Chimie et de Physique,  i.  p.
348.) one volume of muriatic ether, passed
through a porcelain tube at a dull red heat,
is resolved into a mixture of  one volume
olefiant gas, and one volume muriatic gas.
By adding the density of
olefiant gas      =  0.9722 to that of
muriatic acid gas =  1.2840
We have the sum  = 2.2562, which is near-
ly the sp. gr. of the vapour by experiment
= 2.2190.
  When a lighted taper is brought  near
the surface  of  this ether,  it immediately
takes fire, and burns with a greenish flame.
Muriatic gas, carbonic acid, and water re-
sult.  Similar products  are  obtained by
firing a mixture of its vapour with  oxygen,
either by the taper or electric spark.  If
the oxygen be to the vapour in the ratio of
3 to 1, a violent  detonation takes place,
which breaks common eudiometers.
  Water dissolves  of muriatic ether a vo-
lume equal to its own,  at  mean pressure
and temperature. The solution has a sweet
and cooling  taste, analogous to that of pep-
permint.  Although it be very soluble  in
alcohol, water  separates the whole of it.
Chlorine instantly decomposes  muriatic
ether.   Nitrate of silver and protonitrate
of mercury, two salts, which suddenly oc-
casion precipitates  in  waters  containing
muriatic acid, either free or combined with
a salifiable  base,  produce  no immediate
cloud with this ether. It is only after some
hours contact that we begin to perceive an
action; and  even after three months, the
muriatic acid  is  not completely thrown
down.   These  experiments must be made
in phials closed with well ground stoppers.
  The ether produced by treating certain
muriates, especially the fuming muriate,
or chloride  of tin,  with alcohol, is muriatic 
ETH                                 ETH
 ether.  The only difference which  exists
 between the former and this kind, is that
 the ether formed with the acid, is a little
 more volatile than the ether  made with
 the chlorides.
   Nitric ether.  This ether  is prepared by
 distilling equal parts by weight of alcohol,
 and the  aquafortis of commerce.  After
 having introduced them into a retort capa-
 ble of holding double the bulk, it must be
 put in connexion with a Woulfe's appara-
 tus, of which the first bottle is empty, and
 the other four half filled with saturated
 brine. The whole bottles must be put into
 an oblong box, and surrounded with a mix-
 ture of snow and salt.  We then apply a
 gentle heat from a charcoal chauffer.   As
 soon as the liquor begins to boil, we must
 instantly  withdraw the heat, and, if neces-
 sary, check the  violence  of the ebullition
 by the  application of a moist sponge, or
 rag, to the retort.  The operation  is finish-
 ed, when it spontaneously ceases to boil.
 By this time the  product  forms a little
 more than one-third of  the alcohol  and
 acid employed.*
 f A new process for Aritrous  Ether, by Pro-
          fessor R. Hare, M. D.
   The making of nitrous  ether is a critical
 process.  The action of the materials will
 often spontaneously increase so as to pro-
 duce explosion.  It may be conducted with
 ease and  safety by means  of a three necked
 bottle represented by fig. 7.  (See plate, at
 the end of the work, which exhibits the
 eudiometers.)  The two  outermost  necks
 are furnished with  funnels,  and the central
 one with  a tube bent a little more than at
 right angles, and passing through  ice to
 the bottom of a bottle surrounded by the
 same.   The acid and alcohol ought to  be
 very strong.  Let  a  gill  of the latter  be
 poured  into  the  bottle, and then add as
 much acid as will make it boil briskly.
 When the effervescence relaxes, add more
 acid until the addition of this produces no
 great effect.   Then add more alcohol, and
 again more acid,  till the bottle becomes
 one third full.  The ether will be rapidly
 formed  and collected in the  bottle into
 which the recurved tube leads.  This tube
 is represented in the plate  of  about one
 third of the proper length.   There should
 be a triangular wooden trough adapted to
 it for holding ice or snow.
   It might be an improvement  if another
 neck were added, through which the resi-
 dual liquor might be drawn  out. With this
 addition, the distillation of ether might be
 conducted in a way analogous  to that of
 the distillation of whiskey  by the celebrated
 Scotch still.f
   * But ether is not the sole product of the
operation. We obtain also much protoxide
of azote and water, a little azote,  deutox-
ide of azote,  carbonic  acid gas,  nitrous
acid gas, acetic acid,  and a substance ea-
sily carbonized.   We arc thus led to sup-
pose that a portion of the alcohol  is com-
pletely decomposed by the nitric acid, that
it yields almost all its hydrogen to the oxy-
gen of this acid, and that hence result all
the products,  besides the ether, whilst the
alcohol and the nitrous acid unite  to con-
stitute the ether properly so called.  The
whole ether comes over as well as the azote,
protoxide of azote, deutoxide of azote, and
carbonic acid.  As to the water, nitrous
and acetic acids, they are disengaged only
in part, as well as a portion of the alcohol
and nitric acid which escape their recipro-
cal action.   In fact, the easily charred mat-
ter remains in the retort along with a little
acetic acid, about 78  parts  of nitric acid,
60 of alcohol, and 284 of water, supposing
that we had operated upon 500 parts of al-
cohol, and as  much dilute nitric acid.
  It is because there  is  formed so  great  a
quantity of  gas,  that the salt water and re-
frigeration  are required.  Without these
precautions, the greater part of the ether
would be carried off into the  atmosphere;
and even with them, some is always lost.
  On unluting the apparatus, there is found
in the first bottle a large quantity of yel-
lowish liquid, formed of much weak alco-
hol,  of ether,  with nitrous, nitric, and ace-
tic acids.   In  the second, we  find,  on  the
surface of the salt water, a pretty thick
stratum of ether contaminated with a little
acid and alcohol.  In the third,  a thinner
layer of the same, and so on.
  These layers are to be separated from
the water by a long-necked  funnel, mixed
with the liquid of the first bottle,  and re-
distilled from  a retort by a gentle heat, into
a receiver surrounded with ice.  The first
product is an ether, which may be entirely
deprived of acid, by being placed in con-
tact with cold quicklime in a phial, and de-
canted off it, in about half an hour.  From
a mixture  of  about 500 parts of  alcohol,
and as much acid, about 100 parts of ex-
cellent ether may be procured.
  Nitric ether in its ordinary state is a li-
quid of a yellowish-white colour.   It has
an odour analogous to that  of the preced-
ing ethers, but much stronger, so  that its
inhalation into the nostrils produces a spe-
cies of giddiness.   It does not redden lit-
mus.  Its taste is acrid  and burning.  Its
sp. gr. is greater than that of alcohol, and
less than that  of water.   It boils at 70° F.
or at that temperature sustains a  column
equal to 30 inches of mercury.   Poured
into  the hand, it immediately boils, and
creates considerable cold.  It is  sufficient
to grasp in our hands a phial containing it,
to see bubbles  immediately escape.  It takes
fire very readily, and burns quite away,
with a white flame. 
ETH                                ETH
  When agitated with 25 or 30  times  its
weight of water, it is divided into three
portions.  One, the smallest, is dissolved;
another is  converted into  vapour;  and a
third is  decomposed.  The  solution be-
comes suddenly  acid; it  assumes a strong
smell of apples; and, if after saturating
with potash the acid which it contains, it
be subjected to distillation, we  withdraw
the alcohol, and  obtain a  residue formed
of nitrate of potash. We see here that
there is a separation, of one  part  of the
two  bodies, which  constitute the  ether.
Left to itself in a well stopped bottle, the
ether suffers a spontaneous change, for it
becomes perceptibly acid.  By distillation,
acid is instantly developed, which  shows
that heat favours its decomposition.   If in-
stead of exposing the nitric ether to a dis-
tilling heat, we make it traverse an ignited
tube, it is  completely decomposed.  41.5
parts of ether thus decomposed, yielded 5.63
water, containing a little prussic acid; 0.40
of ammonia; 0.80 oil; 0.30 of charcoal; 0.75
carbonic acid; 299 of gases, formed of deu-
toxide of azote, azote, subcarburetted hy-
drogen, and oxide of carbon.   The loss
amounted to 3.72.
  It is very slowly  decomposed by potash.
When combined with nitrous acid gas or
acetic acid, so intimate a union is effected,
that in making the  compound pass through
the most concentrated alkalis, only a small
portion of its acid  is separated.   Accord-
ing to M. Thenard, from whose  excellent
memoir in the first volume of the Memoirei
d'Arcueil the above interesting  facts are
taken, nitric ether is composed in the hun-
dred parts  of
    Carbon     28.65 or 4 primes  3.0
    Azote       14.49   1          175
    Hydrogen     8.54   7         0.875
    Oxygen     48.52   5         5.000
                                 10.625

  Perhaps  with  a little  management  we
might coax these refractory atoms into a
better correspondence with M. Thenard's
results; but in such freaks of fancy,  it is
foolish to indulge. This distinguished che-
mist indeed admitted, that the analysis is
imperfect;  and promised  to  repeat  it in
another and better way by explosion with
oxygen, of which gas, nitric ether, from its
great volatility, quintuples the volume, at
ordinary temperatures.
  Hydriodic ether. M. Gay-Lussac, to whom
the formation of this ether is due, obtained
it by mixing together equal bulks of alco-
hol and a coloured hydriodic acid, sp.  gr.
1.700, distilling the mixture by the heat of
a water bath, and diluting with water  the
product which gradually collects in the re-
ceiver.  The ether precipitates in the form
of  small globules, which  have at first a
milky  aspect,  but which  by their  union
form a transparent liquid.  It is  purified
by repeated washings with water.
  This ether does not redden litmus;  its
smell is strong, and analogous to that of
the rest.  Its sp. gr. is 1.9206 at 72° F.  It
assumes in the  course of a few days a rose
colour, which becomes no deeper  by time,
and which mercury and potash  instantly
remove, by seizing the iodine, which occa-
sions  it.
  Hydriodic ether boils at  156° F.  At  or-
dinary temperatures, it does not kindle by
the approach of a lighted taper to its sur-
face,  but  only  exhales purple  vapours,
when poured  drop by  drop on  burning
coals.  Potassium keeps in it, without al-
teration.  Potash does not instantaneously
change it.   The same may be said of nitric
and sulphurous acids, as well as  chlorine.
Bypassing it through an incandescent tube,
it is converted into a  carburetted inflam-
mable gas; into dark brown hydriodic acid;
into charcoal; and fiocculi, whose  odour is
ethereous, and  which M. Gay-Lussac con-
siders as a sort of ether, formed  of hydri-
odic acid, and  of a vegetable product  dif-
ferent from alcohol.  These flakes melt in
boiling water, and assume on cooling the
transparency and colour  of wax.  They
are much less volatile than hydriodic ether,
and evolve  much more  iodine when pro-
jected on glowing coals.
  Ethers from  vegetable  acids.  Almost all
the vegetable acids dissolve in alcohol, and
separate from it again by distillation, with-
out any peculiar product being formed, how-
ever frequently we act upon the same quan-
tity of acid and alcohol.   Such is the case
at least with the tartaric, citric, malic, ben-
zoic, oxalic, and gallic acids. But this can-
not be  said of  the  acetic.  The  action
of  this acid on  alcohol is such, that by
means of  repeated distillations,  the  two
bodies disappear, and form  a true  ether;
whence it has been inferred by M. Thenard,
that this fluid is  probably the only one of
thevegetable acids at presentknown, which
can exhibit by itself the  phenomena of
etherization. But if instead of putting  the
vegetable acids alone in  contact with alco-
hol, we add to  the mixture one of the con-
centrated mineral acids, we  can then pro-
duce  with  several of them compounds ana-
logous to the preceding ethers.   The  mi-
neral acid  probably acts  here   by con-
densing the alcohol, and elevating the tem-
perature, to such a degree as to determine
the requisite chemical reaction.
   Acetic ether  was discovered by  Scheele,
but first accurately examined by  M. The-
nard.
   Take  100 parts of rectified alcohol, 63
parts of concentrated acetic acid, 17 parts
of sulphuric acid of commerce. After hav-
ing mixed the  whole, introduce them into 
ETH                                 ETH
a tubulated glass retort, connected with a
large globular receiver surrounded with
cold water.   On applying heat, the  liquid
enters into ebullition; and when 123 parts
of ether have passed over, the process may
be stopped.  To render it perfectly pure,
we have only to place it, for half an hour,
in contact with 10 or 12 parts of the caus-
tic potash of the apothecary,  in a  corked
phial, and  to agitate from time to time.
Two strata will form; the undermost thin,
composed of potash and acetate of potash
dissolved  in  water; the uppermost much
more  considerable,  consisting  of  pure
ether, which may be separated by  a long-
necked funnel.  The sulphuric acid does
not enter at all into the composition of this
ether.  It merely  favours  the reaction of
the alcohol and acetic acid.  This mode is
much better  than the old one, of distilling
many times over, the same mixture of ace-
tic acid and alcohol.  Or we may obtain an
excellent acetic ether,  very economically,
by taking 3 parts of acetate of potash,  3 of
concentrated  alcohol,  and 2  of oil of vi-
triol; introducing the mixture into a tubu-
lated retort,  and distilling to  perfect  dry-
ness; then  mixing the  product  with the
fifth part of its weight of oil of vitriol, and,
by  a careful distillation,  drawing off as
much ether as there was alcohol employed.
   Acetic ether is a colourless liquid,  hav-
ing an agreeable odour of sulphuric ether
and acetic acid.  It does not redden litmus
paper, or tincture of turnsole. Its taste is
peculiar.   Its sp. gr. is 0.866, at 44.5° F.
   Under the ordinary atmospheric pres-
sure, it enters into ebullition at 160° Fahr
A lighted taper brought near  its surface at
ordinary temperatures sets fire to it, and it
burns with a yellowish-white  flame.  Ace-
tic acid is developed in the combustion.
It is not changed by keeping.  Water at
62°  dissolves a 7i  part  of  its  weight.
When thus  dissolved  in  water,  it exer-
cises no action on litmus, and it preserves
its characteristic odour and taste.   But
when this  solution is put in contact with
the  half  of  its weight of  caustic  pot-
ash, its odour and taste disappear.  It is
now  completely decomposed.  Hence, if
we submit this liquid to distillation, alco-
hol passes over, and  acetate of potash re-
mains.  Acetic ether is, like all the others,
very soluble  in alcohol, and separable from
alcohol by water.   Its other properties are
unknown.  It is used only in  medicine, as
an exhilarant and diuretic.
   Benzoic  ether.   The presence of a mine-
ral acid is indispensable to its formation,
as well as  that of the remaining vegetable
ethers.
   Take 30 parts of benzoic acid, 60 of al-
cohol, 15 of strong muriatic  acid.  Intro-
duce these ingredients mixed togther into
   Vol.  II.
a tubulated retort, and distil into a refrige-
rated receiver, stopping the operation when
two-thirds have passed over.   Atmosphe-
rical air, and traces of muriatic acid, are
the only gaseous products.  The first por-
tion of the liquid is  alcohol charged  with
a little acid, but the  last will contain a cer-
tain quantity of benzoic  ether, which is
easily separable by water.  A larger quan-
tity of this ether remains  in the retort, co-
vered by a pretty thick stratum, consisting
of alcohol, water, muriatic,  and  benzoic
acids.   By repeated affusions of hot water
into the retort, this stratum will be finally
dissolved.  It is easy thus to procure ben-
zoic ether.  But as so made, it is always
contaminated  with a  portion  of  benzoic
acid, which renders  it solid  at  ordinary
temperatures, and makes  it act on litmus.
It may be purified by agitation with a small
quantity of alkaline solution,  and subse-
quent washing with water. There is  no
muriatic acid found  in this purified ether.
  Ethersfrom oxalic acid, citric, &c. When
we  make a solution of 30 parts of oxalic
acid in 35 parts of pure alcohol, and hav-
ing added 10  parts  of oil of vitriol, we
subject the whole  to distillation till a little
sulphuric ether begins to be  formed, we
shall find that nothing but alcohol slightly
etherized has passed into the receiver, and
there remains in  the retort a brown co-
loured strongly acid liquor, from which,
on  cooling,  crystals  of  oxalic acid fall
down.  But when we dilute the  residual
liquor with  water, a matter is separated
similar to what the  benzoic acid  yielded,
scarcely soluble in water, very abundant,
and which is obtained pure by washing it
with cold water, and removing, by a little
alkali, the excess  of acid  which it retains.
  If we treat in the same  way, the citric
and malic acids, we obtain similar products.
The three substances resulting from these
three  acids  have analogous  properties.
They are all yellowish, somewhat  heavier
than water, void of  smell, perceptibly  so-
luble in water, and very soluble in alcohol,
from which they  are precipitated by Wa-
ter.  They differ  from each other  in taste.
That made from oxalic acid is faintly  as-
tringent; that from the citric acid is very
bitter.  The first  is  the only one  which  is
volatile; it is vaporized with boiling water,
and by this means it is  easily  obtained
white.  When  heated with a  solution  of
caustic potash, they are all three decom-
posed, and yield alcohol,  along with  their
peculiar acids; but  no trace of sulphuric
acid.
   Tartaric acid is also susceptible of com-
bining  with alcohol  like the preceding
acids.  But it presents some curious phe-
nomena.   The experiment of its forma-
tion, must be conducted  in the same way
                       6 
EVA
EVA
as with oxalic acid.  We must employ 30
parts of tartaric acid, 35 of alcohol, 10 of
oil of vitriol, and distil the mixture till a
little sulphuric ether begins to be formed.
If at this period we withdraw the heat from
the retort, the liquor will assume a sirupy
consistence by cooling.  But in vain shall
We pour in water, in hope of separating, as
in the  preceding cases, a peculiar combi-
nation of  the vegetable acid  and alcohol.
But let us add  by degrees solution of pot-
ash, we shall throw down much cream of
tartar; then, after having just saturated the
redundant acid, if we evaporate the liquid,
and treat  it in the cold with very pure al-
cohol, we shall obtain,  by  evaporation of
the alcoholic solution, a substance which,
on cooling, will become more  sirupy  than
the matter was, before being treated  with
potash and alcohol. This substance, which
is easily prepared in considerable quantity,
has a brown colour, and a very bitter and
slightly nauseous taste. It is void of smell
and acidity, and is very soluble in water
and alcohol.  It does not precipitate mu-
riate of lime, but copiously the muriate of
barytes.   When calcined it diffuses dense
fumes,  which  have the odour of garlic,
and at the  same time it  leaves  a char-
coaly  residue,  not alkaline,  containing
much sulphate of potash.   Finally, if dis-
tilled -with potash, it is resolved into a very
strong alcohol, and much tartrate of pot-
ash.  This substance is therefore a combi-
nation analogous to the preceding.  But
what is peculiar to it, is its sirupy state, and
the property it possesses of rendering so-
luble in the most concentrated alcohol the
sulphate of potash, which of itself is  inso-
luble in ardent spirits.  It is perhaps  ow-
ing  to this admixture of sulphate of pot-
ash, that  it wants the oily aspect belong-
ing  to all the  other combinations of this
genus.
   These vegetable-acid ethers may be con-
sidered either  as compounds  of acid  and
alcohol, or of the ultimate  constituents of
the former with those of the latter.*
   Ethiops (Martial).  Black oxide of
iron.
   Ethiops (Mineral).  The black sul-
phuret of mercury.
   Evaporation.  A chemical operation
usually performed by applying heat to any
compound substance, in order to dispel the
volatile parts.  It differs from distillation
in its object, which chiefly consists in pre-
serving the more fixed matters, while the
volatile substances are dissipated and lost.
And the vessels are accordingly different,
evaporation being commonly made in open
shallow vessels, and distillation in an appa-
ratus nearly closed from the external air.
   The degree of heat must be duly regu-
lated in evaporation.  When the fixed and
more volatile matters do not  greatly dif-
fer in their tendency to fly off, the heat
must be very carefully adjusted;  but in
other cases this is less necessary.
  As evaporation consists in the assump.
lion of the elastic form, its rapidity will be
in proportion to the degree of heat and the
diminution of the pressure of the  atmos-
phere.  A current of air is likewise of ser-
vice in this process.
  • In treating of alum, I alluded to a me-
thod of evaporating liquors lately introdu-
ced into  large  manufactories.  A water-
tight stone cistern, about three or four feet
broad, two feet deep, and 20, 30, or 40 feet
long, is covered above by a low brick arch.
At one extremity of this tunnel a  grate is
built, and, at the other, a  lofty chimney.
When the cistern is filled, and a strong fire
kindled  in  the  reverberatory grate,  the
flame and hot air sweep along  the  surface
of the liquor, raise the temperature of the
uppermost  stratum, almost instantly, to
near the boiling point, and draw it off in
vapour.   The great extent, rapidity,  and
economy of this process,  recommend it to
general adoption on the great scale.
   Mr. Barry has lately obtained a patent
for an apparatus, by which vegetable ex-
tracts for the apothecary  may be made at
a very gentle heat and  in vacuo.  From
these two circumstances, extracts thus pre-
pared differ from those in common use, not
only in their physical, but  medicinal pro-
perties.   The taste and  smell  of the ex.
tract of hemlock made in this way are  re-
markably different, as is the colour both of
the soluble and feculent parts.  The form
of apparatus is as follows:—
  The evaporating pan, or still, is  a hemi-
spherical dish of cast-iron, polished on its
inner surface, and  furnished with an air-
tight flat lid.  From the  centre of this a
pipe rises, and bending like the neck of a
retort, it forms a declining tube, which ter-
minates  in a copper sphere of a  capacity
three (four?) times greater than that of the
still.  There is a stop-cock on that pipe,
midway  between the still and  the globe,
and another at the  under side of the latter.
   The manner of setting  it to work is this:
The  juice,  or  infusion,  is  introduced
through a large opening  into the polished
iron  still, which  is then closed, made air.
tight, and covered  with water.  The stop-
cock, which leads  to the  sphere, is also
shut.  In order  to produce  the  vacuum,
steam, from a separate apparatus,  is made
to rush,  by a pipe,  through the sphere, till
it has expelled all  the air, for which five
minutes  are commonly sufficient.   This is
known to be effected, by the steam issuing
uncondensed.  At that instant the copper
sphere is closed, the  steam shut off, and
cold  water admitted on  its external  sur-
face.  The  vacuum thus  produced in the
copper sphere, which contains four-fifths 
EUD                                EUD
 of the air of the whole  apparatus, is now
 partially transferred to the still, by open-
 ing the intermediate  stop-cock.   Thus,
 four-fifths  of the air in the still rush into
 the sphere,  and the stop-cock being shut
 again, a second exhaustion is effected by
 steam in the same manner as the first was;
 after which, a momentary communication
 is again allowed between  the iron still and
 the receiver; by this means, four-fifths of
 the air remaining, after the former exhaus-
 tion, are expelled.  These exhaustions, re-
 peated five or six times, are usually found
 sufficient to raise the mercurial column to
 the height of 28 inches.   The water bath,
 in which the iron still is immersed, is now
 to  be heated, until the fluid  that is to be
 inspissated begins to boil, which is known
 by inspection through a window in the ap-
 paratus, made  by fastening on, air-tight, a
 piece of very strong glass; and the tempe-
 rature at which the boiling point is kept up
 is determined  by a thermometer.  Ebulli-
 tion is continued  until the fluid is inspissa-
 ted to  the proper degree of consistence,
 which also is tolerably judged of by its ap-
 pearance through the glass window.   The
 temperature of the boiling fluid is usually
 about  100° F. but it might be reduced  to
 nearly 90°.
  In the sixth volume  of the Annals  of
 Philosophy,  Dr. Prout has  described  an
 ingenious apparatus by means of which he
 can subject  substances, which he wishes
 thoroughly to dry, to the influence of a gen-
 tle  heat,  conjoined with  the desiccating
 power of sulphuric acid on bodies placed in
 vacuo.  See Congelation.
  From M. Biot's report,  it seems to have
 been ascertained in some French manufac-
 tories, that evaporation goes  on more ra-
 pidly from a liquid boiling in a covered
 vessel from the top of which a pipe issues,
 than when the liquid is freely exposed to
 the air; the fuel or heat  applied,  and ex-
 tent of surface, being the  same in both
 cases.*
  •Euchlorine.  Protoxide of Chlorine.*
  • Euclase.  Prismatic Emerald.*
  Eudiometer.   An  instrument for as-
 certaining the purity of air, or rather the
quantity of oxygen contained in any given
bulk of elastic fluid.  Dr. Priestley's dis-
 covery of the great readiness with which
 nitrous gas combines with oxygen, and is
precipitated in  the form of nitric acid, see
Acid (nitric), was the basis upon which
he constructed  the first instrument of this
kind.
  His method was very simple: a glass ves-
 sel, containing an  ounce by  measure,  was
filled with  the air to be examined, which
 was transferred from it to a jar of an inch
 and half diameter inverted  in water; an
equal measure  of fresh  nitrous  gas  was
added to it; and the mixture was allowed
 to  stand two  minutes.  If the absorption
 were very considerable, more nitrous gas
 was added, till all the oxygen appeared to
 be absorbed.  The residual gas was  then
 transferred into a glass tube two feet long,
 and one-third of an inch wide, graduated
 to  tenths  and  hundredths of  an ounce
 measure; and thus the quantity of oxygen
 absorbed was measured by the diminution
 that had taken place.
   Von Humboldt proposes that the nitrous
 gas should be examined, before it is used,
 by agitating a given quantity  with a solu-
 tion of sulphate of iron.
   Sir H. Davy employs the nitrous gas in a
 different manner.  He passes it into a satu-
 rated solution of green muriate or sulphate
 of iron, which becomes opaque and almost
 black when fully impregnated with the gas.
 The air to be tried is contained in a small
 graduated tube, largest at the open end,
 which is introduced into the solution, and
 then gently inclined toward the horizon,
 to accelerate the action, which will be com-
 plete in  a few minutes, so as to  have ab-
 sorbed all the oxygen.  He observes, that
 the measure must be taken as soon as this
 is done, otherwise the bulk of the air will
 be increased  by a slow decomposition  of
 the nitric acid formed.
   Volta had  recourse to the accension  of
 hydrogen gas.  For this purpose, two mea-
 sures of  hydrogen are introduced into a
 graduated tube  with three  .of the air  to
 be  examined,  and fired by the  electric
 spark.  The diminution of bulk, observed
 after the vessel had returned to its origi-
 nal temperature, divided by three,  gives
 the quantity of oxygen consumed.
   Phosphorus  and  sulphuret of potash
 have likewise been employed in eudiome-
 try.
   A piece of phosphorus may be introdu-
 ced by means of a glass rod  into a tube
 containing the air to be examined standing
 over water, and suffered to remain till it
 has absorbed  its oxygen; which, however,
 is a slow process.  Or a glass tube may be
 filled with mercury  and inverted, and a
 piece of  phosphorus, dried  with blotting
 paper, introduced,  which will of course
 rise to the top.  It is there  to be  melted,
 by  bringing a  red-hot iron near the glass,
 and the  air to  be admitted by little  at a
 time.  At each  addition the  phosphorus
 inflames; and,  when the whole has been ad-
 mitted, the  red-hot  iron may be  applied
 again, to ensure the absorption of all the
 oxygen.  In either of these  modes l-40th
 of the residuum is to be deducted, for the
 expansion of the nitrogen, by means of a
 little phosphorus which it affords.
  Professor Hope of Edinburgh employs a
 very convenient  eudiometer, when  sulphu-
 ret of potash or Sir H. Davy's liquid is used.
It consists of two glass vessels, one to hold 
EUD                                EUD
the solution of sulphuret of potash, or other
eudiometric liquor, about two inches  in
diameter, and three inches high,  with a
neck at the top as usual, and a tubulure, to
be closed with a stopple  in the side near
the bottom: the other is a tube, about eight
inches and a half long, with a neck ground
to fit  into that of the former.  This being
filled  with the air  to be examined, and its
mouth covered with a flat piece of glass, is
to be  introduced under waier, and there in-
serted into the mouth of  the bottle.  Tak-
ing them out of the  water, and inclining
them  on one side, they are to be well shak-
en, occasionally  loosening the  stopper in a
basin filled with water, so as to admit this
fluid  to occupy the vacuum  occasioned by
the absorption.  Bottles of much  smaller
size than here mentioned, which is calcula-
ted for public exhibition, may generally be
employed; and, perhaps, a graduated tube,
ground  to fit into the  neck of a small
phial, without projecting within it, may be
preferable on many occasions, loosening it
a little under water, from time to time, as
the absorption goes on.
   * Mr. Dalton  has written largely on the
nitrous gas eudiometer.   He  says, that 21
measures  of oxygen can unite  with 36
measures, or  twice 36 — 72 measures, of
nitrous gas; that  is,  100 with  171.4 or
342.8.  Phil. Mag. vol. xxiii.  and  Manch.
Mem. new series, 1.
   M.  Gay-Lussac, in  his excellent memoir
on nitrous vapour and  nitrous gas,  has
proved, that no confidence can be reposed
in these directions of Mr. Dalton  for ana-
lyzing gases.  Nitrous gas is there  fully
 demonstrated to be a compound of equal
 volumes of oxygen and  azote, and the ap-
 parent contraction of their volume is null;
 for  100 of the  one and 100 of the other
 produce exactly 200 of nitrous gas. Nitric
 acid  is composed of 100 parts of azote, and
 200 of oxygen,  or of 100 oxygen  and 200
 nitrous gas; =  (100 o. -f- 100 az.) Nitrous
 vapour, or, more accurately speaking, ni-
 trous acid gas, results from the combination
 of 100 of oxygen with  300 of nitrous  gas.
 Hence, by giving predominance alternate-
 ly to the oxygen and to the nitrous gas,
 we obtain 300 of absorption and nitric acid,
 or 400 of absorption and nitrous acid.   The
 nitrous  acid gas is an identical compound,
 very  soluble  in water, which it colours at
 first  blue, then green,  and  lastly  orange-
 yellow  This liquid, with the alkalis, forms
  nitrites.   These clear and simple facts con-
  tinue the whole theory of the formation of
  the nitrous and nitric acids, by means of ni-
  trous gas and oxygen, and perfectly explain
  the differences of the results of all those who
  have operated with them. We have now on
  It is stated above, that we obtain nitric
acid  and  an absorption  represented by
three, or nitrous  acid and a diminution of
volume  represented by four, every time,
according  as the oxygen or nitrous  gas
predominates in  the mixture of these two
gases.  Now, since the object is to with-
draw the whole oxygen from air, we must
add  the nitrous  gas in excess to it, and
cause thus a diminution of volume, four
times greater than the volume of the con-
tained oxygen.   Notwithstanding this pre-
caution, if we make the mixture in a very
narrow  tube, the  nitrous vapour would be
absorbed with  difficulty by the water, on
account of the narrow contact,  and  agita-
tion would become necessary.   But in this
case, nitrous gas, to the amount of 10 or 12
per  cent, would  be absorbed.  It is from
this cause, that on mixing 100 parts of air
with 100 of nitrous gas, very variable ab-
sorptions were  obtained, of which the mean
was 93; whilst air, containing at utmost 21
per  cent of oxygen, the absorption should
be only four times this quantity, or 84. Nor
is it a matter of indifference, to put the ni-
trous gas in the tube before, or after the
other gas; for if we introduce it first, there
might  be formed both nitrous and nitric
acids.  Knowing  these two causes of error,
it is  easy to avoid them,  by  obeying the
following injunctions of M. Gay-Lussac.
   Instead of selecting a very narrow  tube,
as Mr.  Dalton prescribed, we must  take a
very wide tube, a tumbler for example, and
 after having introduced into it 100 of the
 air  to  be examined,  we must  pass  into it
 100 parts of the  nitrous gas.  There is  in-
 stantly exhibited a red vapour, which dis-
 appears very  speedily without agitation,
 and after half a minute, or a minute at most,
 the absorption may  be regarded as com-
 plete.  We transfer  the residuum into a
 graduated tube, and we shall find the ab-
 sorption to be almost uniformly 84  parts,
 provided  atmospheric air  was used, one-
 fourth  of which  = 21, indicates the quan-
 tity per cent of oxygen.
   M. Gay-Lussac shows, by numerous ex-
 periments, the accuracy of the above pro-
 cess, in  varied  circumstances.  We  have
 thus the advantage of estimating the pro-
 portion of oxygen in any gas, by an absorp-
 tion four times greater than its own volume;
 so  that the errors of experiment are  re-
 duced to one-fourth,  on  the  quantity of
 oxygen.   Now,  as we can  never commit a
 mistake of four degrees, the error must be
 less than one  per cent.   We  must  never
 agitate, or use an under proportion  of ni-
 trous gas, nor yet cany its excess too far,
 on account of its solubility in  water.
    An  apparatus for analyzing gases con-
ly to show, how we may render the use of  taining  oxygen or chlorine, by  explosion
nitrous gas perfectly accurate in eudiome-  with hydrogen, was  communicated by me
try.                                      to the Royal  Sodety of  Edinburgh, and 
EUD                                EUD
published in the volume of their Transac-
tions for 1817 and 1818.
Description of an Apparatus for the Ana-
   It/sis of Gaseous Matter by Explosion.  Bv
   Dr. Ure.
   The analysis of combustible gases, and
supporters of combustion, reciprocally, by
explosion, with the electric spark, furnish-
es, when it  can be  applied,  one  of the
speediest and most elegant methods  of che-
mical  research.  The risk of failure  to
which the chemist is exposed, in operating
with the simple tube, from the ejection of
the mercury, and escape or introduction of
the air; or of injury from the  bursting  of
the glass, by the forcible expansion of some
gaseous mixtures, has given rise to several
modifications of apparatus.
   Volta's mechanism, which is employed
very much at Paris, is complex and  expen-
sive^ while it is hardly applicable to expe-
riments  over mercury.  Mr. Pepys' inge-
nious contrivance, in which the glass tube
is connected  with a metallic spring, to di-
minish the shock of explosion, is liable also
to some of the above objections.
   A very simple form of instrument occur-
red to me  about two years ago, in  which
the atmospheric air, the most  elastic and
economical of all springs, is employed  to
receive  and  deaden the  recoil.  Having
frequently used it since that time, I can
now recommend  it to the chemical  world,
as possessing every requisite advantage  of
convenience,  cheapness, safety, and pre-
cision.
   It consists  of a glass syphon, having an
interior diameter of from 2-10ths to 4-10ths
of an  inch.  Its  legs are of nearly equal
length, each  being from six to nine  inches
long.  The open extremity is slightly fun-
nel-shaped, the other is hermetically seal-
ed; and has  inserted near it, by the blow-
pipe, two platina wires.  The outer end of
the one wire is incurvated  across, so  as
nearly to touch the edge of the aperture;
that of the other is formed into a little hook,
to allow a small spherical button to be at-
tached to it, when the electrical spark is to
be transmitted.  The two legs of the  sy-
phon are from one-fourth to one-half inch
asunder.
  The sealed leg is graduated, by intro-
ducing successively equal weights of mer-
cury from  a  measure  glass tube.   Seven
ounces troy and 66 grains, occupy the space
of a cubic inch; and 34i grains represent
t^-jt Part °^ tnat volume.   The other leg
may be graduated also, though this is not
necessary. The instrument is then finished.
  To use it,  we first fill the whole syphon
with mercury or water, which a little prac-
  § The  price of the  apparatus  is three
guineas.
tice will render easy.  We then introduce
into the open leg, plunged into a pneuma-
tic trough, any convenient quantity of the
gases, from a glass measure tube,  contain-
ing them  previously mixed in determinate
proportions.  Applying a finger to the ori-
fice, we next remove it from the trough in
which it stands, like a simple tube; and by
a little dexterity, we transfer the  gas into
the sealed leg  of the syphon.  When we
conceive enough to have been passed up,
we remove the  finger, and next bring the
mercury to a level in both legs, either by
the addition of a few drops, or by the dis-
placement of a  portion, by thrusting down
into it a small cylinder of wood.  We now
ascertain,  by careful inspection, the volume
of included gas.  Applying the fore-finger
again to the orifice, so as also to touch the
end of the platina wire, we then approach
the pendent ball or button to the electrical
machine,  and transmit  the spark.   Even
when the  included gas is considerable in
quantity, and of a strongly explosive pow-
er,  we feel at the instant nothing but a
slight push or  pressure  on the tip of the
finger.  After explosion,  when condensa-
tion of volume  ensues, the finger will feel
pressed down to the orifice by the superin-
cumbent atmosphere.  On gradually slid-
ing the finger to one side, and admitting
the air, the mercurial column in the sealed
leg will rise more or less  above that in the
other.  We then pour in this liquid metal,
till  the equilibrium  be again restored,
when we  read  off as  before, without any
reduction, the true resulting volume of gas.
  As we ought  always to leave two inches
or more of air, between the finger and the
mercury,  this atmospheric column serves
as a perfect recoil spring, enabling  us to
explode very large quantities without any
inconvenience or danger.   The manipula-
tion is also, after a little practice, as easy
as that of the single tube.  But a  peculiar
advantage of this detachable instrument is,
to enable us to keepour pneumatic troughs,
and  electrical  machine,  at any distance
which convenience  may  require;  even in
different  chambers, which, in the case of
wet weather, or a damp apartment, may be
found necessary to ensure electrical  exci-
tation.  In the  immediate  vicinity of the
water pnuematic cistern,  we know how of-
ten the electric spark refuses to issue from
a good electrophorus, or even little ma-
chine.  Besides,  no  discharging rod or
communicating  wire  is  here  required.
Holding the eudiometer in the left hand,
we turn the handle of the machine, or lift
the electrophorus plate with the right, and
approaching the little ball, the explosion
ensues.  The electrician is well aware, that
a spark so small as to excite no unpleasant
feeling in the finger, is capable, when drawn
off by a smooth ball, of inflaming combusti- 
EUD                                EUD
 hie gas.  Even this trifling circumstance
 may be obviated,  by hanging on a slender
 wire, instead of applying the finger.
    We may  analyse the residual gaseous
 matter, by introducing either a liquid or a
 solid reagent.  We first fill the open leg
 nearly to the brim with quicksilver, and
 then place over it the substance whose ac-
 tion on the gas  we wish to try.   If liquid,
 it may be passed round into the sealed leg
 among the gas; but if solid, fused potash,
 for example,the gas must be brought round
 into the open leg, its  orifice having  been
 previously closed  with a cork  or stopper.
 After a proper interval, the gas being trans-
 ferred back into the  graduated  tube, the
 change of its volume may be accurately de-
 termined.   With  this  eudiometer, and  a
 small mercurial pneumatic cistern, we may
 perform pneumatic analyses on a very con-
 siderable scale.
   It may be desirable in some cases, to have
 ready access to the graduated leg, in order
 to dry it speedily.  This advantage is ob-
 tained, by  closing the  end of the syphon,
 not hermetically, but with a  little brass cap
 screwed on,  traversed vertically by a pla-
 tina wire insulated in a bit of thermometer
 tube.  After the apparatus has been charg-
 ed with gas for explosion, we connect the
 spherical button with the top of the wire.
   With  the above instrument  I  have ex-
 ploded half a cubic inch of hydrogen mixed
 with a quarter of  a cubic inch  of oxygen;
 as also, a bulk nearly equal of an olefiant
 gas  explosive mixture, without  any un-
 pleasant concussion or noise; so completely
 does the air-chamber  abate  the expansive
 violence, as wellas the loudness of the re-
 port.  Projection of the  mercury, or dis-
 placement of the gas, is obviously impossi-
 ble.  Edin. Phil. Trans. January 1818.*

 f Account of .Xexv  Eudiometers, invented by
  Robert Hare, M.  D. Professor of Che-
  mistry, l/c  in the Medical  Department  of
  the University of Pennsylvania.

  Amongthe operations of chemistry, none
probably are more difficult than those called
eudiometrical, in which aeriform substances
are analyzed.
  Elastic fluids are so liable  to contract or
expand with the slightest change of tem-
perature or pressure, that it  is requisite to
have  the surface of the portion under ad-
measurement exactly in the same level with
that of the water or mercury employed to
confine it, and the heat of the hand may
render the result inaccurate.  There is no
simple mode of causing the  surface of the
gas in a measure glass to form a plane cor-
responding with the brim.   The transfer
of small portions of gas without loss, espe-
cially from large bells into  small tubes is
very difficult.  Hence there  is trouble, de-
lay and waste.
   I shall proceed to describe some instru-
 ments which I have lately invented, and
 which appear to be free from  the  disad-
 vantages above described.  They are all
 essentially dependent on one  principle for
 their superiority.§
   A recurved glass tube is furnished with
 a sliding wire of iron or copper, graduated
 into two hundred  parts.  The  process  of
 making wire by drawing it through a hole,
 renders  its circumferences  of necessity
 every where equal and homologous.  Con-
 sequently equal lengths will contain equal
 bulks.
   The wire slides .through a cork soaked
 in bees-wax and oil, and compressed by a
 screw, so that neither air nor water can
 pass by it.
   The length of the longer leg is fifteen
 inches, that of the shorter one  six inches.
 The bore of the tube is from -j^- to Tsg- of an
 inch in  diameter,  but converges towards
 the termination of the shorter leg to an
 orifice  about  large enough to  admit a
 brass pin.  Over this a screw is sometimes
 affixed so as to close it when necessary.
   The tube being filled with water or mer-
 cury, and the wire pushed into  it  as far as
 it can go, on drawing this out again any de-
 sired distance, an  equivalent bulk  of air
 must enter the capillary orifice if open. By
 forcing the rod back again into the tube,
 the air  must be proportionably excluded.
 Thus the movements of the  sliding wire
 are  accompanied by a corresponding in-
 gress or egress of air;  and to know  how
 many  divisions of the  former have  been
 pushed into the tube  or  withdrawn  from
 it, is the same as to know how much air
 has been drawn in or expelled.
   If instead of allowing the orifice  to be
 in the open air, it be introduced within a
 bell glass, holding gas over the  pneumatic
 apparatus, on pulling out  the wire, there
 will be  a corresponding  entrance of gas
 into the instrument; and it must  be evident
 that if the point of the gas measurer be
 transferred to the interior of any other re-
 cipient, the gas which had entered, or any
 part of it may be made to go into any such
 recipient by reversing  the motion of the
 wire.  As the hands are, during this ope-
 ration, remote from the part of the  tube
 which  contains the aeriform matter,  no
 expansion can arise from this source,  and
 the operation is so much  expedited that
 there is much less chance of variation from
 any other cause.  By taking  care  to have
the surface of the gas  in the  bell glasses
below that of the fluid in  the cistern, the
density of the former will be  somewhat
too great, but on bringing the orifice of
the gas measurer on a level with the  sur-
face of the fluid in the cistern, the gas no

  § See the plate at  the end of the  work. 
EUD                                EUD
longer subject to any extra pressure, will
assume its proper volume, the excess  be-
ing seen to escape in bubbles.  Should the
tube, in lieu of water, be  filled with any
solution, calculated to absorb  any  gas, of
which the proportion, in any mixture is to
be ascertained, and if the quantity of ab-
sorption which can take place while  the
wire is drawing out, is deemed  unworthy
of attention, we have only to  introduce
the shorter leg of the tube into the con-
taining  vessel,  as  above described, and
draw out the  wire  to two hundred on its
scale; then depressing the point below the
surface of the fluid in the  pneumatic  cis-
tern,  in the  usual time with due agitation,
all the  gas  which the fluid can take up,
will disappear.  The quantity will be re-
presented by the number of divisions which
remain  without the tube, after pushing in
the wire just so far as to exclude the resi-
dual gas.
  Should  it be deemed an object to avoid
the possibility of any absorption  during
the time occupied in the retraction of the
sliding wire, or should it be desired to ex-
pose the gas to a large quantity of the ab-
sorbing fluid, an additional vessel is used,
which is of an oblate spheroidal form, with
a large  neck ground to fit the  shorter  leg
of a gas measurer, and furnished at the op-
posite apex  with a tube, of which the bore
converges to a capillary opening, surmount-
ed by a screw, as already described, on the
point of the gas measurer  simply.  This
vessel (in shape not unlike a turnip) is filled
with the absorbing fluid, and the gas mea-
sure, being duly charged with gas as above
described, inserted into it.   By the action
of the sliding wire, the  gas is  propelled
into the spheroid, where  by agitation and
time the absorption is completed.   Mean-
while the orifice of the spheroid should be
kept open, and under water, so as to per-
mit the latter to take place of  that portion
of the gas  which disappears.—Whatever
remains unabsorbed, is expelled from  the
glass spheroid, as in the  case  of the tube
when used alone; and the divisions  on  the
rod remaining without, will show how much
the fluid has taken up.
  When atmospheric air, or oxygen gas is
to be analyzed by nitrous  gas,  the glass
spheroid is filled with water, and inverted
with its orifice closed over the well of  the
pneumatic cistern.  It should be supported
by a wire stand, so as to leave the neck un-
obstructed.  Any number of measures of
nitrous gas,  and of oxygen gas, or  atmos-
pheric air, may then be drawn into  the
measurer, and expelled into the spheroid
successively, and the  absorption estimated
as already explained.  When the residuum
is too great to be expelled by returning the
whole of the rod into the tube; by  depres-
sing the orifice of the spheroid just under
the surface of water, the wire may be again
gently retracted, water taking its place; and
the movement may thus be alternated, till
the whole of the remaining gas is excluded.
  In order to apply this principle to Vol-
ta's process of ascertaining by explosion
the quantity of  hydrogen or oxygen gas
present in a mixture, the gas measurer  is
made as much stronger, as eudiometers are
usually, when intended to be  so used.   It
is in like manner drilled  so as  to receive
wires for passing the electric  spark.  The
instrument being charged with the gases
successively  in  any required proportion,
closed by the screw, and an explosion Ac-
complished; to fill any consequent vacuity,
the orifice is to be opened just below the
surface of water or mercury.   The quan-
tity destroyed by the combustion is then
ascertained by the sliding wire.
  This experiment is  more accurately per-
formed by means of mercury than  water.
From this fluid, concussion,  or even the
partial vacuum produced by  the gaseous
matter, may extricate  air, and thus  vitiate
results.  There  ought always to be a con-
siderable  excess of gas not  liable  to be
acted on.   The  activity  of the inflamma-
tion is lessened,  and the unconsumed air
breaks the shock.
  I have  found  the galvanic ignition pro-
duced by  a small calorimotor  preferable
to the electric spark.  Suppose  a piece of
iron to  be filed  down in the middle for
about one half  of  an inch to  about one
third of the original diameter.  The whole
is cemented into the perforation drilled in
the tube,  so as that the smallest part may
extend across the bore.   The wire should
then be cut off' at about one third  of an
inch from the tube, so as to stand out from
it on each side  about that distance.   If
these protruding wires be severally placed
in the forceps of a calorimotor  and the
plates subjected  to an acid, the small part
of the wire within the tube is vividly ig-
nited, and any gas in contact with it must
explode.  The interior wire is best  made
of platina, and may in that case be screwed
into two larger  pieces of a baser metal:
or baser metal may  be fastened on  it, by
drawing through a wire plate, and the pla-
tina duly denuded by a file where it crosses
the  bore.
  The calorimotor which I have used for
this purpose, consists  of eleven plates of
copper, and a like number of zinc placed
alternately within one-fourth of  an inch of
each other.- those of the same kind of me-
tal being all associated by means a metal-
lic stratum of tin  cast  over  them.  The
two heterogeneous galvanic surfaces thus
formed, have  each soldered to  them  a
wire in a vertical position, and slit,  so as
to present a fork or  snake's mouth.  The
wires are just so far apart as to admit the 
EUD                                EUP
 pas measurer between them,  and so that
 the wires of the latter may easily be pres-
 sed into the snake mouths. It is better that
 the wires of the gas measurer should  be
 flattened in such  manner as to present a
 larger surface for contact. There must also
 be an  oblong square box or hollow paral-
 lelopipedon of such a width as just to ad-
 mit the  calorimotor, and  more than dou-
 ble its length and depth.   The calorimotor
 is placed within this box, at one end of it,
 about  an inch below  the brim.  Diluted
 acid is poured so as to occupy  the lower
 half of the vessel, until  it nearly  reaches
 the plates.  A plunger, consisting of a wa-
 ter tight box, or solid block  of wood,  is
 then made to occupy the other side of the
 little cistern. The depression of this causes
 the rise of the acid among the plates  in
 the calorimotor, and consequently the ig-
 nition of a wire forming  a communication
 between the surfaces.
  This apparatus may be  constructed  in
 the circular form, by so placing two con-
 centric coils, or several concentric hollow
 cylinders of copper  and  zinc, alternately
 within the upper half of  a glass jar as  to
 admit of a plunger in the middle,  which
 in this case may be of an apothecary's stop-
 per round or bottle.  The acid solution
must occupy the lower half of the vessel,
unless  when the plunger raises it.
  I am under the impression that there  is
no form in which a pair  of galvanic sur-
faces can be made so powerful in propor-
tion to their extent, as in the above men-
tioned.  The zinc is every where opposed
by two copper surfaces by having this me-
 tal only a small fraction in excess.
  ExplanatioTi of the plate. (See the end of
 the work.)
  Fig. 1. Sliding  rod  eudiometer or gas
 measurer, surmounted by its spheroidal re-
 cipient,  r r,  sliding rod  graduated  into
 twenty divisions, each subdivided into ten,
 so as to make two hundred parts.  At m f,
 are male and female screws, (forming what
 mechanics call a stuffing box), by means
 of  which a cork soaked  in bees-wax and
 oil is compressed around the rod.  At n,
 is the neck of the recipient, ground to  fit
 the recurved tube which enters it.  At  S,
 is a screw, by which to close the capillary
 orifice of the recipient.
  Fig. 2. Eudiometer upon the same prin-
 ciple, but made stouter in order to resist
 the explosion of inflammable mixtures.  W
 W, wire to be ignited.
  Fig. 3. Displays a  construction  of the
 sliding rod,  by which  when desirable,
 greater accuracy may be  attained  in the
 measurement  of gas.  A  smaller rod  of
 wire is made to slide within the larger.
 Whatever may be the ratio (in bulk) of the
 rods to each other, the lesser may be  gra-
 duated to give thousandths, by ascertain-
 ing how far it must be moved to produce
 the effect of  a movement of one division
 on the large  rod, and  dividing the obser
 ved distance into ten parts.
   Fig. 4.  Represents an apparatus adapt-
 ed to  explode an inflammable mixture, as
 mentioned in the preceding article, and no
 contrived as to be a substitute for the well
 known apparatus in which an electropho-
 rus is employed to ignite  hydrogen gas.
 Moisture in the air suspends the action of
 that apparatus but  does not interfere with
 the one here represented.
   A A, a cistern divided by a water-tight
 partition, which separates the holder G,
 from a calorimotor situated under C,  and
 a plunger P, contained in the other part of
 it   W W, wires severally soldered to the
 different galvanic surfaces, and forked or
 slit  at their ends, so as to embrace the
 wire of an eudiometer for the explosion of
 inflammable mixtures, as mentioned in the
 preceding article.  At f f,  are forceps (se-
 verally soldered in  the same way) for hold-
 ing a wire to  be  ignited by the galvanic
 influence.
  These wires and the plates with which
 they are connected may be seen  at fig. 5,
 where there is an enlarged drawing of the
 calorimotor and its wires.
  It is supposed  to be situated below the
 edge of the cistern which is supplied with
 diluted acid reaching within  a little dis-
 tance of the plates.
  c, a  cock soldered to a pipe communica-
ting with the  inside of the gasometer,  hh,
 a gallows and guide wire, for regulating
 the rise of the gasometer.
  The construction of this will be better
 comprehended from fig. 6, where it repre-
 sents  the  tray for holding the zinc, by
 means of which hydrogen is to be evolved.
 The tray is supported on the  pipe in  the
 axis of the vessel by a sliding band and
 screw, so that it  may be raised or depres-
 sed at pleasure.   When this tray is  co-
 vered  with granulated zinc, and the lower
 vessel is filled with acid so as to cover it,
 hydrogen must be generated until it occu-
 pies so much of  the air-holder, as to  de-
 press the acid from off the zinc.   Suppos-
 ing the apparatus thus prepared, on  de-
 pressing the plunge P, fig.  4,  the acid in
 the cistern A  A,  will he forced up among
 the galvanic surfaces, and  cause the wire
 at f f, to be  ignited.   Turning  the cock
 while the wire is red-hot, the hydrogen will
 be emitted and inflamed.j-
  Euphorbium.   A  gum-resin exuding
 from a large oriental shrub, Euphorbia offi-
 cin. Linn.
  It is brought  to us immediately from
 Barbary,  in  drops of an  irregular form;
 some of which upon being broken are found
 to contain little thorns, small twigs, flow-
 ers, and other vegetable matters; others arc 
EXC
EYE
hollow, without any thing in their cavity:
the tears in general are of a pale yellow
colour externally, somewhat white with-
inside ; they easily break betwixt the fin-
gers.   Sp.  gr.  1.124.   Slightly applied
to the tongue, they affect it with a very
sharp biting taste ; and, upon being held
for some  time in the mouth, prove  vehe-
mently acrimonious, inflaming and exul-
cerating the fauces, &c.  Euphorbium is
extremely troublesome to pulverize, the
finer part of the powder, which flies off,
affecting the head in a violent manner.
The acrimony is so great, as to render it
absolutely unfit for any  internal use.  It
is much employed in the veterinary artas
an epispastic :
  * The  following constituents  were
found in  Euphorbium by Braconnot :
  Resin,     ....      37.0
  Wax,     ....       19.0
  Malate of lime,    -     -    -   20.5
  Malate of potash,     ... 2.0
  Water,      -     -    -     -   5.0
  Woody matter,      -      -      13.5
  Loss,      -      -      •       3 0

                                 100.0
  The resin is  excessively acrid, poison-
ous, reddish-coloured,  and transparent.
It dissolves in sulphuric and nitric  acids,
but not in alkalis, in which respect it dif-
fers from other resins.  Euphorbium it-
self is pretty soluble in alcohol.*
  • Excrements.  The constituents  of
human feces, aocording to the recent ana-
lysis of Berzelius, are the  following :
 ' Water,    -                     73.3
  Vegetable  and animal remains,    7.0
  Bile,     ---           0.9
  Albumen,                       0.9
  Peculiar extractive matter,      - 2.7
  Salts,       -      -      - .1*2
  Slimy  matter, consisting  of picro-
    mel, peculiar animal matter, and
    insoluble residue,       -      14.0

                                 100.0
  The salts  were to one another in the
following proportions :
  Carbonate  of soda,    -     -     0.9
  Muriate of soda,     -     -     0.1
  Sulphate of  soda,    -    -     0.05
  Ammon. phos. magn.     -    - 0.05
  Phosphate of lime,   -      -     0.1

                                  1.20
  Thaer and Einhof obtained, by ignition,
from 5840 grains  of the excrenTents  of
cattle, fed at the stall chiefly  on turnips,
the following earths and salts :■,
  Lime,*            -             12.
  -Phosphate of lime,    -     -    12-5
  Magnesia,     -            -       2.0
      Vol. II,
  Iron,    -          -     -    5.0
  Alumina with some manganese, 14.0
  Silica,    .--    -     52.0
  Muriate and sulphate of potash,  1.2

                                98.7*

  Expansion. See Caloric.
  Extract.  When  decoction is carried
to such a point as to  afford a  substance
either solid or of the consistence of paste,
this residual product is called an extract.
When chemists speak  of  extract, they
most  commonly  mean the  product of
aqueous decoction ; but the earlier che-
mists frequently speak of spirituous ex-
tract.
  Extracts thus prepared are mixtures of
several of the materials  of vegetables,
whence they  differ greatly, according to.
the plants from which they are obtained;
but modern  chemists distinguish by the
name of extract, or  extractive matter, a
peculiar substance, supposed to be one of
the immediate materials  of vegetables,
and the same in all, when separated from
any foreign admixture, except as  the pro-
portion of its constituent principles may
vary.   See Evaporation.
  Ete.  The humours of the eye had ne-
ver been examined with any degree of ac-
curacy till lately by M. Chenevix.  Most
of his experiments were made with the
eyes of sheep, as fresh as they could be
procured.
  The aqueous humour is a clear, trans-
parent liquid, with little smell or taste,
and at  the temperature of 60°, its speci-
fic gravity is 1.009.  It consists of water,
albumen, gelatin  and muriate of soda.
  The crystalline contains a much larger
proportion of water, and no muriate.  Its
specific gravity is 1.1.
  The  vitreous  humour,  when  pressed
through a rag to free it from its capsules,
differed in nothing  from the aqueous,
either in its specific  gravity or chemical
nature.
  Fourcroy mentions a phosphate as con-
tained  in these humours, but M. Chenevix
could discover none.
  The  humours of the human eye gave
the same products, but the specific gra*
vity  of the  crystalline was only 1.079,
and that of the aqueous and vitreous hu-
mours 1.0053.
  The eyes of oxen differed only in the
specific gravity  of the parts, that of the
crystalline being 1.0765, and  that of the
other humours 1 0088.
  The specific gravity of the crystalline
is not  equal  throughout, its density  in-
creasing from the surface to the centre.
—ZVii7. Transt 1803- 
FAT
FAT
F
  * pAHLUNITE.  Automalite,  a  sub-
    ■"-  species of octohedral corundum.*
   Farina.  Vegetable flour.
  • Fat.   Concerning the nature of this
important product of animalization, no.
thing definite  was known, till M. Chev-
reul devoted himself with meritorious zeal
and perseverance  to   its  investigation.
He has already published in  the Annales
de  Cbimie, seven successive memoirs on
the subject, each of them surpassing its
predecessor in interest.  We shall in this
article give a brief abstract of the whole.
  By dissolving fat in a large quantity of
alcohol, and observing the  manner in
which its  different portions were acted
upon by this substance, and again sepa-
rated from it, it is concluded that fat is
composed of an  oily substance, which re-
mains fluid at the ordinary temperature
of the atmosphere; and of another fatty
substance, which is much less  fusible.
Hence it follows, that fat is not to be re-
garded as  a simple  principle, but as a
combination of the above two principles,
which may be separated without  altera-
tion. One of these substances melts at
about 45°, the other at 100° ; the same
quantity of alcohol which dissolves 3.2
parts of the oily substance, dissolves 1.8
only of the fatty substance ; the  first  is
separated from the alcohol in the  form of
an oil; the second in that of small silky
needles.  See Elain.
   Each of the constituents of natural fat
was then  saponified  by the addition of
potash ; and an  accurate description giv-
en of the compounds which were formed,
and of the proportions of their constitu-
ents.  The oily substance became saponi-
fied more readily than  the fatty substance;
the residual fluids in  both cases contain-
ed  the sweet  oily principle; but the
quantity  that proceeded  from the  soap
formed of the oily substance, was  four  or
 five times as much as that from the fatty
 substance; the latter  soap was found to
 contain a much  greater proportion of the
pearly matter than the former, in the pro-
 portion of 7.5 to 2.9; the proportion  of
 the fluid fat was the reverse, a greater
 quantity of this being found in the soap
 formed from the oily substance of the fat.
    When the principles which constitute
 fat unite with potash, it is probable that
 they experience a change in the propor-
 tion of their elements ; this  change de-
 velopes at least three bodies, margarim,
fluid fatf and the sweet principle ; and it is
 remarkable, that it takes place without
 the absorption  of any foreign substance,
 or the disengagement of any of the ele-
 ments which are separated from each
 other.  As this change is effected by the
 intermedium of  the alkali, we may con-
 clude that  the newly  formed principles
 must have a strong affinity  for salifiable
 bases, and will in many respects  resem-
 ble the acids ;  and, in fact, they exhibit
 the leading characters of acids in redden-
 ing  litmus, in decomposing the alkaline
 carbonates  to unite to their bases, and in
 neutralizing the specific properties of the
 alkalis.
   Having already pointed  out the analo-
 gy between the  properties of acids and
 the principles into which fat is converted
 by means of the  alkalis, the next object
 was to examine the  action  which other
 bases have  upon fat, and to observe the
 effect of water, and of the cohesive force
 of the bases upon the process of saponifi-
 cation.  The substances which the author
 subjected to experiment, were soda, the
 four  alkaline  earths,  alumina, and the
 oxides of zinc, copper, and lead.  After
 giving a detail of the processes which he
 employed with  these substances respec-
 tively, he draws the following  general
 conclusions :—Soda,  barytes, strontian,
 lime, the oxide of zinc, and the protoxide
 of lead, convert  fat into margarine, fluid
 fat, the  sweet principle,  the yellow colour-
 ing principle,  and the  odorous principle,
 precisely in the  same manner as potash.
 Whatever be the base that has been em-
 ployed, the products of saponification al-
 ways exist in the same relative propor-
 tion.  As the above mentioned bases form
 with margarine and the fluid fat,  com-
 pounds which are insoluble in water, it
 follows, that the action of this liquid, as
 a solvent of soap, is not essential to the
 process of saponification.   It is remar-
 kable that the oxides of zinc and of lead,
 which are insoluble in water, and which
 produce compounds equally  insoluble,
 should  give the same results with potash
 and soda,  a circumstance  which  proves
 that  those oxides have a strong alkaline
 power.   Although the  analogy  of mag-
 nesia to the alkalis  is, in other respects,
 so striking,yet we find that it cannot con.
 vert fat into soap under the same circum-
  stances with flie  oxides of  zinc  and
  lead. 
FAT
FAT
  It was found that 100 parts of hog's
lard were reduced to the completely  sa-
ponified  state by 16.36 parts of potash.
See Elain and  Acid (Margabic).
  The properties of spermaceti were next
examined:  it melts at about 112°;  it is
not much altered by distillation ; it  dis-
solves readily in hot alcohol,  but sepa-
rates as the fluid cools ; the solution has
no effect in changing the colour of  the
tincture  of litmus, a circumstance,  as it
is observed, in which it differs from mar-
garine, a substance which, in many res-
pects, it  resembles.  Spermaceti is capa-
ble  of being saponified by potash, with
nearly the  same phenomena as when we
submit hog's-lard to the action of potash,
although the operation is effected with
more difficulty.
  The author's general conclusion res-
pecting the fatty matter of dead bodies
is, that even after  the lactic acid, the lac-
tates, and  other ingredients,  which are
less  essential,  are removed from it,  it is
not  a simple,  ammoniacal  soap, but a
combination of various fatty substances
with ammonia, potash, and lime.  The
fatty substances  which were separated
from alcohol, had different melting points
and  different   sensible  properties.   It
follows, from M. Chevreul's experiments,
that the  substance which  is the least fu-
sible, has  more  affinity for bases than
those which are more so.  It is observed,
that adipocere possesses the characters of
a saponified fat ;  it is soluble in boiling
alcohol  in  all  proportions, reddens lit-
mus, and unites  readily  to potash, not
only without losing its weight, but with-
out having  its fusibility or other proper-
ties  changed.
  M. Chevreul has shown, that hog's-
lard, in its  natural state, has not the pro-
perty of combining with alkalis ; but that
it acquires it  by  experiencing  some
change in the proportion of  its elements.
This change being induced by the action
of the alkali, it follows that the bodies
of the new formation must have a deci-
ded affinity for the species of body which
has  determined  it.   If we apply  this
foundation of the theory of saponification
to the change into fat, which  bodies bu-
ried in the earth experience, we shall find
that it explains the process in a very sa-
tisfactory manner.  In  reality the fatty
matter is the combination of the two adi-
pose substances with ammonia, lime, and
potash;  one of these substances has the
same sensible properties with  margarine
procured from the soap of hog's-lard; the
other, the orange-coloured oil, excepting
its colour, appears to have a strong ana-
logy with the fluid fat.  From these cir-
cumstances, it is probable that the forma-
tion of the fatty matter may be the result
of a proper saponification produced by
ammonia, proceeding from the decompo-
sition of the muscle, and by the potash
and lime, which proceed from the de-
composition of certain salts.
 The author remarks, that he has hither-
to made use of periphrases when speak-
ing of the different bodies that he has
been describing, by supposing that their
nature was not sufficiently determined.
He now, however, conceives, that he may
apply specific names to them, which will
both be more  commodious,  and, at the
same time,  by being made appropriate,
will point out  the  relation  which these
bodies bear to  each other.  The follow.
ing is the nomenclature which he  after.
wards adopted:—The crystalline matter
of human biliary calculi is  named choles-
ferine, from the Greek words ^ok» bile,
and f tf io(  solid ;   speimaceti  is named
cetin, from k<itoc,  a whale ;  the  fatty
substance  and the  oily substance  are
named  respectively,  stearin  and  elain,
from the words «"«*§ fat, and txmov oil;
margarine and the fluid fat obtained  af-
ter  saponification,  are named margaric
acid and oleic acid, while the term  cetic
acid, is applied to what was named sapo-
nified  spermaceti.  The   margarates,
okates and cetates  will be the generic
names of  the soaps  or combinations,
which these acids are capable of forming
by their union with salifiable bases.
   Two portions of human fat were exa-
mined,  one taken  from the kidney,  the
other from the thigh ; after some time
they both of them manifested a tendency
to separate into two distinct  substances,
one of a solid, and the other of a fluid
consistence ; the two portions differed
in their fluidity and their melting point.
These variations depend upon the  differ-
ent proportions of stearin  and  elain;
for the concrete part of fat is a combina-
tion of the two with an excess  of stearin,
and the  fluid part is a combination with
an excess of elain.   The fat from the
other animals was then examined, princi-
pally with respect to their melting point
and their solubility in alcohol ; the mel-
ting point was not always the same in the
fat of the same species of animal.  When
 portions of the fat of different sheep  are
 melted separately at the temperature  of
 122°, in some specimens the thermometer
 descends to 98.5°, and rises again to 102°,
 while in others it descends to 104°,  and
 rises  again to 106°.    A  thermometer
 plunged into the fat of the ox melted at
 122°, descended to 98.5°, and rose again
 to 102°.  When the  fat of the jaguar
 was melted  at  104°,  the thermometer
 descended to 84°, and rose again to about
 $5°; but a considerable portion  of  the 
FAT
FAT
fat sHll remained in a fluid state.   U ith
respect to the solubility of the  different
kinds of fat in alcohol, it  was found that
100  parts of it  dissolved  2.48 parts of
human fat, 2.26  parts of sheep's fat, 2 52
parts ofthe  fat  of the ox, 2.18 parts of
the fat of the jaguar, and about 2.8 parts
ofthe fat of the hog.
  M. Chevreul next examines the change
which is produced in the different kinds
of fat respectively by the action of potash.
All the kinds of fat are capable of being
perfectly saponified, when excluded from
the contact of the air ; in all of them there
was  the production ofthe  saponified fat
and the sweet  principle; no  carbonic
acid was produced,  and the soaps formed
contained no acetic acid, or only slight
traces of it.  The saponified  fats had"
more tendency  to  crystallize in needles
than the fats in their natural state ;  they
were soluble in  all proportions in boiling
alcohol  of the specific gravity of 0.821.
The  solution, like  that of the saponified
fat ofthe hog, contained both the marga-
ric and the oleic acids.  They were less
fusible than the fats  from which  they
were formed ;   thus,  when human fat,
after being  saponified, was melted,  the
thermometer became  stationary at 95°,
when the fluid began to congeal; in that
of the sheep, the  thermometer  fell to
118.5°,  and  rose to 122°; in that of the
ox it remained stationary at 118.5° ; and
in that of the jaguar at 96.5°.
  The saponified fat of the sheep and the
ox, had the  same degree of solubility in
potash and soda, as that  ofthe hog.
100 parts of the  fat of^v
  the sheep when sapo- ^       f
  nified  were dissolv- {         v
  ed by              J
100 parts of the same >
10.27 of soda.
Y
04 of potash.
  were dissolved by
100 parts of the sapo-
  nified'fat of the ox  C 15.42 of potash.
  were dissolved  by  j
100 parts of the same  |  10>24 of soda.
  were d ssolved  by   y
100 parts of the saponi-'
  fled fat of the hog
  were dissolved  by
100 parts of the  same 5    2   f   ^
  were dissolved by  y
  The following table contains the pro-
portions of the saponified fat, and ofthe
matter soluble in water, into which  100
parts ofthe fat are capable of being chang-
ed :—
               Human fat.
      Saponified  fat,
      Soluble matter,
          Fat of the sheep.
      Saponified fat,
      Soluble matter,
          Fat ofthe ox.
      Saponified fat,        95
95
 5

951
 4.9
      Soluble matter,        8
           Fat of the hog
      Saponified fat,        ©4.7
      Soluble matter,         5.3
  M. Chevreul next gives an account of
the analysis of fat by alcohol.
  The method of analysis employed was
to expose the different kinds of fat  to
boiling alcohol, and to suffer the mixture
to cool ; a portion of the fat  that had
been dissolved was then separated in tyvo
states of combination ;  one  with an ex-
cess of stearin was deposited,  the other
with an excess of elain  remained in  so-
lution.  The first was separated by filtra-
tion; and  by distilling the filtered fluid,
and  adding a little water  towards the
end  of the operation, we obtain the se-
cond in the retort, under the form of an
alcoholic  aqueous  fluid.  The distilled
alcohol which had been employed in the
analysis of human fat  had no sensible
odour ; the same was the case with that
which had served for the analysis of the
fat  of the ox, of the  hog,  and of the
goose.  The alcohol which had been em-
ployed in  the analysis ofthe fat of the
sheep,  had a slight odour of candle-
grease.
  The varieties  of stearin from the dif-
ferent species of fat, were found to pos-
sess the  following properties:—They
were all of a beautiful white colour ; en-
tirely, or almost without odour, insipid,
and having no action upon litmus.—Stea.
rinfrom man.  The thermometer which
was plunged into it when melted fell to
105.5°,  and rose again to 120°.   By cool-
ing, the stearin  crystallized  in very fine
needles, the surface of which was flat.—
Stearin of the sheep. The thermometer
fell to 104°, antl  rose again to 109.5° ; it
formed itself into a flat mnss; the centre,
which cooled more slowly than theedges,
presented small and finely radiated nee-
dles.— Stearin of th" ox.   The thermo-
meter fell to 103°,  and rose again 111°;
it formed  itself into  a mass,  the surface
of which   was flat, over which were dis-
persed a number of minute stars, visible
by the microscope; it was slightly semi-
transparent.—Stearin ofthe hog.   It ex-
haled the odour of hog's-lard  when it
was melted.   The  thermometer fell  to
100.5°, and rose again to   109.5°.   By
cooling, it was reduced into a  mass the
surface of which was very unequal, and
which appeared to be formed  of small
needles.  When  it  cooled  rapidly,  the
parts which touched the sides ofthe ves-
sel bad the semi-transparency of coa«ni-
1'ited albumen.—Stearin  of the  q-oose.
The thermometer  fell to 104°,  and rose
again to  109.5°; it was  formed into  a
fiat mass.
   With respect to the solubility of these
different bodies in alcohol,  100 parts of 
FAT
FAT
boiling alcohol, of the specific gravity of
0.7952,  dissolved,
 Of human stearin,          21.50 parts.
 Of the stearin of the sheep,  16.0f
   All the soaps of stearin were analyzed
 by the same process as the soap ofthe fat
 from which  they had been extracted;
 there was procured from tbem the pearly
 super-margarate of potash and the oleate;
 but the first  was  much more abundant
 than the second.  The margaric acid of
 the stearins had precisely the same ca-
 pacity for saturation  as that which was
 extracted from the soaps formed of fat.
 The margaric acid of the stearin of the
 sheep was fusible at 144°, and that ofthe
 stearin of the ox at 143.5°, while the mar-
 garic acids of the hog and the goose had
 nearly  the same fusibility with the  mar-
 garic acid ofthe fat of these animals.
   On Spermaceti; or,  as  M. Chevreul
 technically calls it, cetin.   In  the  fifth
 memoir, in which we  have an account of
 many of the properties of this substance,
 it was stated, that it is not easily saponi-
 fied by potash, but that it is converted by
 this  reagent  into  a  substance  which is
 soluble in water, but has not the saccha-
 rine flavour ofthe sweet principle of oils;
 into an acid analogous to the margaric,
 to which the name of cetic was applied;
 and  into another acid, which was con-
ceived to be analogous to the oleic. Since
he wrote the fifth memoir, the author has
Ofthe stearin ofthe ox,    15 48 parts.
Ofthe stearin of the hog,  18.25
Ofthe stearin ofthe goose, 36.00
1  made the following observations on this
t  subject:—1. That the portion of the soap
I  of cetin which is insoluble  in water, or
r  the cetate of potash, is in part gelatinous,
J  and in part pearly: 2. That two kinds of
'•  crystals were produced from the cetate
f  of potash which  had  been  dissolved in
   alcohol: 3. That the  cetate of potash ex-
'<  posed, under a bell glass,  to the heat of
   a stove, produced a sublimate of a fatty
   matter  which  was not acid. From this
   circumstance M. Chevreul was led to sus-
   pect, that the supposed cetic acid might
   be a combination, or  a mixture of marga-
   ric acid and of a fatty body which was
   not acid;  he accordingly treated a small
i  quantity of it with  barytic  water, and
i  boiled the soap which  was formed in al.
''  cohol;  the greatest part of it was not dis-
   solved, and the alcoholic solution, when
   cooled, filtered, and distilled, produced a
   residuum of fatty matter which  was not
   acid.   The suspicion being thus confirm-

     § This means the salt which we obtain
   after  having neutralized by barytes the
   product ofthe  distillation ofthe aqueous
   fluid, which was procured from  the soap
   that had been  decomposed  by  tartaric
   acid.
Saponification by potash.
The human stearin j Saponified fat, 94.9
produced, by saponi-^
fication,             [soluble matter, 5.1
Stearin ofthe
sheep.
Stearin ofthe
ox.
Stearin of the
hog.
Stearin ofthe
goose.
                      "   It  was  fusible at 123.5°; it crys.
                      ! tallized in small  needles joined in
                      ..the form of a funnel.
                      ',   The  sirup  of the sweet principle
                      ^weighed 8.6, the acetate 0.3.§
                      f  It began  to  become  opaque  at
  Saponified fat, 94.6 1 ^f' and thfe-Se'0mo!"eter **am«
    r          '       j stationary at 127.5°;  it crystallized
                      Lin small fine radiated needles.
                         The sirup of the sweet principle
                       weighed 8,  the acetate 0.6; it had a
                      C rancid odour.
                      f  It began to become solid at 129°,
                     J but  it  was   not perfectly  so until
                      j 125.5°; it crystallized in  small nee-
                      l_dles united into flattened globules.
                      C  The sirup of the sweet principle
                      £ weighed 9.8, the acetate 0.3.
                      f  It began  to  grow solid at 129°,
 f Saponified fat, 94.65J and the thermometer became station-
 |   v                 \ ary at 125.5  ; it crystallized in small
■^                     ^needles united into flattened globules.
 | Soluble matter, 5.35 S   Thke "ir"P °f the tsw*e} PrinciPle
 L                    £ weighed 9, the acetate 0.4.
                      C   It became solid  at 119°;  it crys-
 ("Saponified fat, 94.4  J tallized  in  needles  united  in the
                      {.form of a funnel.
  Soluble matter, 5.6  5   Th« »'1™P of the swreet P™P*e
                      * weighed 8.2.
t.Soluble matter, 5.4
Saponified fat, 95.1
Soluble matter, 4.9
' 
FEL
FEL
 ed, M.  Chevreul determined to subject
cetin to a new train of  experiments.
Being treated with boiling  alcohol, a ce-
tin was procured which was fusible at
120°, and a yellow fatty matter which
began to become solid at 89.5°, and which
at 73.5°, contained a fluid oil, which was
separated by filtration.
   Saponification of the Elainsby Potash.~
The determination ofthe soluble matter
which the elains yield to water in the
process of saponification, is much  more
difficult than the determination of the
same point with respect to  the stearins.
The  stearins  are  less  subject to  be
changed than the elains: it is less  diffi.
cult to obtain the stearins in a uniform.
ly pure state; besides the saponified fats
of the stearins being less  fusible  than
the saponified elains;  it is more easy to
weigh them without  loss.   The elains
ofthe sheep, the hog, the jaguar, and the
goose, extracted by alcohol, yield by the
action of potash.
      Of saponified fat,  89 parts,
      Of soluble matter, 11.
The elain of the ox extracted in the
same manner yields,
      Of saponified fat, 92.6 parts,
      Of soluble matter,  7.4.
  The different kinds of fat, considered
in their natural state, are distinguished
from each other by their colour, odour,
and fluidity.
  The stearins of the sheep, the ox, and
the hog, have the same degree of solubili-
ty in alcohol; the stearin  of man is a lit-
tle more soluble, while that of the goose
is twice as much so.   The elains of man,
ofthe sheep, the ox, the jaguar, and the
hog, have a specific gravity of about .915;
that of the goose of about .929.  The
elains of the sheep, the ox, and the hog,
have the same solubility  in  alcohol; the
elai'n of the  goose is a little more solu-
ble.   On the other  hand,  the margaric
acids of man, of the hog, of the jaguar,
and of the goose, cannot  be distinguish-
ed from each other; those of the  sheep
and the ox differ a few degrees  in  their
melting  point, and a little also in their
form. As for the slight differences which
the oleic acids present, they are not suf-
ficiently precise for us to be able to par-
ticularize them-  See Acid (Oleic).
   Fecula.  See Starch.
   * Fecola.   Green of  plants.   See
Chlorophyle.*
   •Feldspar. This important mineral
genus is distributed by Professor Jameson
into four species, viz. prismatic feldspar,
pyrauwdal feldspar, prismato-pyramidal
feldspar, and rhomboidal feldspar.
   I. Prismatic feldspar has- 9 sub-species;
 1. Adularia; 2. Glassy feldspar;  3. Ice-
 spar; 4. Common feldspar^ 5. Labrador
feldspar; 6. Compact feldspar; 7. Clink-
stone;  8. Earthy common feldspar; and,
9. Porcelain earth.
   1. Adularia-   Colour greenish-white;
iridescent; and in thin plates, pale flesh-
red by transmitted light.  Massive and
crystallized.  Primitive form, an  oblique
four-sided prism, with 2 broad and 2 nar.
row lateral planes; the  lateral edges are
120° and 60°. Secondary forms; an ob.
lique four-sided  prism, a broad rectangu-
lar six-sided prism, a six-sided table, and
a  rectangular four-sided prism.   Some-
times  twin  crystals occur.  The lateral
planes of the prism are  longitudinally
streaked.  Lustre splendent, intermedi-
ate between vitreous and pearly.   Clea-
vage threefold.  Fracture imperfect con.
choidal.   Semi-transparent.  A beautiful
pearly light is sometimes seen, when the
specimen is viewed in the direction of the
broader lateral planes.  Refracts  double.
Harder than  apatite,  but  softer than
quartz.  Easily  frangible.  Sp.  gr. 2.5.
It melts  before the blow-pipe,  without
addition, into a  white-coloured transpa-
rent glass.  Its  constituents are, 64 sili-
ca, 20 alumina, 2 lime, and  14 potash.—
Vauquelin.
   It occurs in contemporaneous veins, or
drusy  cavities, in  granite and gneiss, in
the island of Arran, in Norway, Switzer-
land, France, and  Germany.  The finest
crystals  are found in  the mountain of
Stella, a part of  St. Gothard.  Rolled pi«-
ces, exhibiting  a most beautiful pearly
light, are collected in the island  of Cey-
lon.  Moonstone  adularia  is  found in
Greenland ; and all the varieties in the
United States.   Under the name of moon-
stone  it is worked by lapidaries.  Ano-
ther variety from Siberia is called sun.
stone by the jewellers.  It is of a yellow-
ish colour, and numberless golden spots
appear  distributed  through its whole
substance.  These  reflections of light
are either  from minute fissures,  or irre.
gular  cleavages  of the mineral. The
aventurine feldspar of Archangel appears
to be also sunstone. It  is  the hyaloides
ofTheophrastus.
   2.  Glassy feldspar.    Colour  grayish-
white.  Crystallized in broad rectangu-
lar four-sided prisms, bevelled on the ex-
tremities Splendent and vitreous. Clea-
vage threefold.  Fracture uneven. Trans-
parent. Sp. gr. 2.57- It melts   without
addition into a  gray semi-transparent
glass.   Its constituents are, 68 silica, 15
alumina,  14.5 potash,  and 0.5  oxide of
iron.—Klapr. It  occurs  imbedded  in
pitch-stone porphyry in Arran and Hum.
   3. Ice spar. Colour grayish white. Mas-
sive, cellular and porous; and  crystal-
lized in small, thin, longish six-sided ta-
bles.  The lateral planes are longitudi- 
                FEL

nally streaked.  Lustre vitreous.   Clea-
vage imperfect.  Translucent and trans-
parent.  Hard as common feldspar, and
easily frangible.  It  occurs along with
nepheline,  meionite,  mica,  and  horn-
blende, at Monte Somma near Naples.
  4.  Common feldspar. Colours white and
red, of various shades ; rarely green and
blue. Massive, disseminated, and crystal-
lized in a very oblique four-sided prism ;
anacuterhombus; elongated octohedron ;
a  broad equiangular six-sided prism ; a
rectangular four-sided prism ; and twin
crystals ; which  forms  are diversified
by various  bevelments and truncations.
Cleavage threefold.   Lustre more pearly
than vitreous.   Fracture uneven.  Frag-
ments rhomboidal;  and have only four
splendent faces.  Translucent on the ed-
ges.  Less hard  than  quartz.  Easily fran-
gible.  Sp. gr.  2.57.   It is fusible with-
out addition into a gray semi-transparent
 glass.  Its constituents are as follows :
            Siberian  Flesh-red Feldspar from
          green  feldspar,  feldspar.    Passau.
 Silica,        62 83     66.75     60.25
 Alumina,    17.02     1/.50     22.00
 Lime,          3.00      1.25      0.75
 Potash,      13.00     12.00     14.00
 Oxide of iron,  1.00      0.75water, 1.00

              96.85     98.25     98.00
              Vauq.     Rose.   Bucholz.
   Feldspar is one ofthe most abundant mi-
 nerals, as it forms a principal constituent
 part of granite and gneiss, and occurs
 occasionally mixed  with mica-slate and
 clay-slate.   It  is  also  a constituent of
 whitestone and syenite.  It forms the ba-
 sis of certain porphyries.  Greenstone is
 a compound of common feldspar and horn-
 blende.  The  most  beautiful crystals of
 it occur in the Alps of Switzerland, in
 Loin hardy, France,  and Siberia, in veins
 of contemporaneous formation with the
 granite  and gneiss rocks.   It occurs
 abundantly in  transition mountains, and
 in those of the secondary class.  Under
 the name of petunze,  it is an ingredient
 of Chinese porcelain.   When the green
 varieties are spotted with white, they are
 named aventurine feldspar.  Another green
 variety from  South America is called the
 Amazon-stone, from the river where it is
 found.
    5. Labradorgfeldtpar.  Colour gray of
 various  shades  When light falls on it
 in oertain  directions, it exhibits a great
 variety, of beautiful colours,  It  occurs
 massiVe, or in  rolled pieces.  Cleavage
 splendent.  Fracture glistening.  Lustre
 between vitreous  and pearly.  It breaks
 into rhomboidal fragments.  Translucent
 in a very low degree.   Less easily fran-
 gible than common  feldspar. Sp.  gr. 2.6
 to 2.7.   It is  less   fusible than common
              FER

feldspar.  It occurs  in rolled masses  of
syenite, in which  it  is associated with
common  hornblende,  hyperstene,  and
magnetic  ironstone, in the island of St.
Paul on the coast of Labradore.  It is
found round Laurwig in Norway.
  6.  Compact feldspar. Colours, white,
gray, green and red.  Massive,  dissemi-
nated, and  crystallized  in  rectangular
four-sided prisms. Lustre glistening, or
glimmering.  Fracture   splintery   and
even   Translucent only  on  the edges.
Easily frangible.  Sp. gr.  2.69.  It melts
with difficulty into a whitish enamel.  Its
constituents are, 51 silica, 30.5 alumina,
11.25 lime, 1.75 iron, 4 soda, 1.26 water.
—Klapr.   It occurs in mountain masses,
beds and veins : in the Pentland  hills, at
Sala, Dannemora,  and Hallefors in Swe-
den ; in the Saxon Erze-gebirge, and the
Hartz.
  7.  Clinkstone ;  which see.
   8. Earthy common feldspar. This seems
to be disintegrated common feldspar.
  9. Porcelain earth.   See Clay.
   II. Pyramidal feldspar. See Scapolite,
 and Elaolite.
   HI. Prismato-pyramidal feldspar.  See
 Meionite.
   IV. Rhomboidal feldspar. See Nephe-
 LINE.
   Chiastolite and sodalite have  also been
 annexed  to this  species by Professor
 Jameson.*
   • Fermestatios. When aqueous com-
 binations of  vegetable  or animal  mat-
 ter are exposed to ordinary  atmospheri-
 cal temperatures, they speedily undergo
 spontaneous changes, to which  the gene-
 ric name of fermentation has been given.
 Animal liquids alone, or mixed with ve-
 getables, speedily  become  sour.  The
 act which occasions this alteration  is
 called acetous fermentation; because  the
 product  is, generally speaking, acetic
 acid, or vinegar.  But when a moderate-
 ly  strong solution of saccharine matter,
 or saccharine matter and starch, or sweet
 juices  of  fruits, suffer this  intestine
 change, the result is an  intoxicating li-
 quid, a beer, or wine ; whence the pro-
 cess is called  vinous fermentation.  An
 ulterior change,  to  which all moist ani-
 mal and vegetable matter is liable, ac-
 companied by  the disengagement  of a
 vast quantity of fetid gases, is called the
 putrefactive fermentation.
 ..  Each of these  processes goes on most
 rapidly at a somewhat elevated tempera-
 ture, such as 8Q° or 100° F.  It is for
 these reasons, that in tropical countries,
 animal and vegetable substances are so
 speedily  decomposed.
    As the ultimate constituents of vegeta-
 ble matter are  oxygen, hydrogen, and
 carbon;  and of animal matter, the same 3 
FEU
FER
principles with azote, we can readily un.
derstand that all the products of fermen-
tation must be merely new compounds of
these three or four ultimate constituents.
Accordingly, 100 parts ot real vinegar, or
acetic acid, are resolvable, by MM. Gay-
Lussac  and  Thenard's analysis,  into
50.224 carbon + 46.911 hydrogen and
oxygen, as they exist in  water,  + 2.863
oxygen in excess.  In like manner, wines
are all resolvable into the same ultimate
components,  in proportions somewhat
different.   The aeriform results of putre-
factive fermentation are in like manner
found to be,  hydrogen, carbon, oxygen,
and azote, variously combined, and asso-
ciated with minute quantities of sulphur
and phosphorus.  The  residuary  matter
consists of the  same principles, mixed
with the saline and earthy parts of animal
bodies.
  Lavoisier was the first philosopher, who
instituted, on right principles, a series of
experiments to investigate the phenomena
of fermentation, and they were so judici-
ously contrived, and so  accurately con-
ducted, as to  give results, comparable to
those derived from the more rigid methods
ofthe present day.   Since then M. The-
nard and M. Gay-Lussac have each con-
tributed most important researches.  By
the labours of these three illustrious die.
mists, those material metamorphoses, for-
merly quite mysterious, seem susceptible
of a satisfactory explanation.
  1. Vinous fermentation.  As sugar is a
substance  of  uniform  and  determinate
composition, it has been made choice of
for determining the changes which arise
when its solution is fermented into  wine
or alcohol.  Lavoisier justly regarded it
as a true vegetable oxide, and stated its
constituents to be, 8 hydrogen, 28 carbon,
and 64 oxygen, in 100 parts. By two dif-
ferent analyses of Berzelius, we have,
      Hydrogen,  6 802    6.891
      Carbon,   44.115  42.704
      Oxygen,   49.083   50.405
              100 000  100.000
MM. Gay-Lussac and Thenard's analysis
ives,
     Hydrogen  6.901     3
     Oxygen, 50 o3 3
     Carbon,   42.47   42.47
                100.00 10000
  It has been said, that sugar  requires to
be dissolved in at least 4 parts of water,
and to be mixed with some yeast, to cause
its fermentation to commence. But this
is a mistake.   Sirup stronger than  the
above will ferment  in  warm weather,
without addition.  If the  temperature be
low, the sirup weak, and no yeast added,
acetous fermentation  alone will take
 place. To determine the vinous, there-
 fore, we must mix certain proportions of
saccharine  matter, water  and yeast, and
place them in a proper temperature.
  To observe the chemical changes which
occur, we  must dissolve 4 or 5 parts of
pure sugar in 20  parts of water, put the
solution into a matrass, and add 1 part of
yeast.  Into the mouth of the matrass a
glass  tube  must  be luted, which is re-
curved, so as to dip into the  mercury of
a pneumatic trough- If the apparatus be
now placed in a temperature of from 70°
to 80°, we shall speedily observe the si-
rup to become muddy, and a multitude of
air  bubbles to form all around the fer-
 ment.  These unite, and attaching them-
 selves to particles of the yeast, rise along
 with it to the surface, forming a stratum
 of froth.   The  yeasty matter will  then
disengage itself from the air, fall to the
bottom of the vessel, to re-acquire buoy-
ancy a second time by attached air  bub<
bles, and thus in succession. If we operate
on 3 or 4 ounces of sugar, the fermenta.
tion will be very rapid during the first ten
or twelve hours; it will then slacken, and
terminate in the course of a few days. At
this period the  matter being deposited,
which disturbed the transparency ofthe
liquor, this will become clear.
  The following changes have now taken
place:  1. The  sugar  is wholly,  and the
yeast partially, decomposed.  2. A quan-
tity of alcohol  and carbonic  acid,  toge-
ther nearly equal in weight to the sugar, is
produced.  3. A white matter is formed,
composed of hydrogen, oxygen, and car-
bon, equivalent to about half the weight
of the decomposed ferment.   The carbo-
 nic  acid passes over into the pneumatic
apparatus ; the alcohol may be separated
 from  the vinous  liquid  by  distillation,
 and the white matter  falls down to the
 bottom of the  matrass with the remain-
 der of the yeast.
   The quantity of  yeast  decomposed
 is very  small.   100 parts of sugar re-
 quire, for  complete decomposition,  only
 two and a half of that substance, suppos-
 ed to be in a dry state.   It is hence very
 probable, that the ferment, which has a
 strong affinity for oxygen, takes a  little
 of it  from  the saccharine particles,  by
 a part of <its hydrogen and carbon, and
 thus  the equilibrium being, broken be-
 tween the  constituent principles of the
 sugar, these so react on each .other, as te
 be transformed into alcohol and carbonic
 acid. If* we consider the composition of
 alcohol, we shall  find no difficulty in tra-
 cing  the steps of this transformation..4'
 we take 40 of carbon + 60 of water, 01
 its elements, as the true  constituents of
 sugar, instead of 42.47+ 5753, and
 convert these  weighs into volumes,  vr. 
FER                                 FER
shall have for the composition of that body,
very nearly,                   by weight,
1st, 1 volume vapour of carbon, = 0.416
    1 volume vapour of water, = 0.625
 or, 1 volume vapour of carbon,
    1 ditto hydrogen gas,
    $ ditto oxygen;
or, multiplying each by 3,
    3 volumes vapour of carbon,
    3 ditto hydrogen,
    5 ditto oxygen.
2d, Let us bear in mind that alcohol is
composed of
1 vol. olefiant gas =  ^ vols. vap. of carb.
             °      £2 vols, hydrogen.
ldo.vap.ofwater= \\ vo\ hydr°Sen>
                    C 3 vol. oxygen.
3d, 1 vol. carbonic  acid = 1 vol. oxygen +
1 vol. vapour of carbon.
  4. Neglecting the minute products which
the yeast furnishes, in the act of fermenta-
tion, let us regard only the alcohol and car-
bonic acid. We shall then see, on compa-
ring the composition of sugar to that  of
alcohol, that to transform sugar into alco-
hol, we must withdraw from it one volume
of vapour of carbon, and  one volume  of
oxygen, which form by their union one vo-
lume of carbonic acid gas.  Finally, let us
reduce the volumes into weights, we shall
find, that 100 parts of sugar ought to be
converted, during fermentation, into 51.55
of alcohol, and 48.45 of carbonic acid.
  Those who are  partial to atomical lan-
guage will see that  sugar may be  repre-
sented by
                    Atoms.
3 vol. vap. of carbon, = 3 = 2.250  40.00
3 do. hydrogen,  -   = 3 = 0.375    6.66
|- do. oxygen    -   =. 3 = 3.000  53.33

                            5.625  99.99
And alcohol, by		
2 vol. carbon,	= 2= 1.500	52.16
3 do. hydrogen, -	= 3 = 0.375	13.04
I do. oxygen,	= 1 = 1.000	34.80
                            2.875  100.00
And carbonic acid, by
1 vol. oxygen,    -   = 2 =  2.00   72.72
1 do. vap. of carbon, = 1 =  0.75   27.28

                                  100.00

  If, therefore, from the sugar group, we
take away one atom of carbon, and  two of
oxygen, to form  the carbonic acid  group
below, we leave an atomic assemblage for
formng alcohol, as in the middle.  For this
interesting developement of the relation be-
tween the ultimate constituents of sugar on
the one hand, and alcohol and carbonic acid
on the other, we  arc indebted to M. Gay-
Lussac.
   Vol.  II.
  The following beautiful comparison, by
the same philosopher, illustrates these me-
tamorphoses:
Sulphuric ether is composed of
                  Dens, of vapour.
2 vol. olefiant gas= 1.9444")   9 -,Q.
1 do. vap. ofwater= 0.62503   ^oy*-
And alcohol is composed of
2 vol. olefiant gas= 1.9444")  . 9__-  ,Q7<>
2 do. vap. of water= 1.25005 ~z"""""""*■'**'*'
  Hence to convert alcohol into ether, we
have  only to withdraw from  it one-half of
its constituent water.
  Let us nowsee how far experiment agrees
with the theoretic deduction, that 100 parts
of sugar, by fermentation, should give birth
to 51.55 of absolute alcohol, and  48.45 of
carbonic acid.  In Lavoisier's elaborate ex-
periment, we find, that 100 parts of sugar
afforded,    Alcohol,      57.70
            Carbonic acid, 35.34

                         93.04
  Unfortunately, this great  chemist has
omitted to state the specific  gravity of his
alcohol.
  If we assume it to have been 0.8293, as
assigned for the density of highly rectified
alcohol in the 8th table of the appendix to
his Elements, we shall find 100 parts of it
to contain, by Lowitz's  table, 87.23 of ab-
solute alcohol, if its temperature had been
60°.  But as 54.5° was the  thermometric
point indicated in taking sp. gravities, we
must reduce the density from 0.8293 to
0.827.  We shall then find 100 parts of it,
to consist of 88 of absolute alcohol, and 12
of water.  Hence, the  57.7 parts  obtained
by  Lavoisier will become 50.776 of abso-
lute alcohol, which is  a surprising accor-
dance with  the theoretical quantity 51.55.
But about four parts ofthe sugar, or l-25th,
had not been decomposed.  If we add two
parts of alcohol for  this, we would have  a
small  deviation from theory on the  other
Bide.   There is no reasonable ground for
questioning the accuracy of Lavoisier's ex-
periments  on fermentation.   Any- person
who considers  the  excessive  care he has
evidently bestowed on them,  the finished
precision of his apparatus,  and the com-
placency with  which he compares  " the
substances submitted to fermentation, and
the products resulting from that operation,
as forming an algebraic equation," must be
convinced that the results are  deserving of
confidence.  Unlike the  crude and contra-
dictory researches,  which  modern vanity
blazons in our Journals, those of Lavoisier
on fermentation, like the coeval inquiries
of Cavendish on air, will never become ob-
solete.
  M. Thenard, in operating  on a solution
of 300 parts of sugar, mixed with  60 of
                        8 
FER
FER
yeast, at the temperature of 59°, has ob-
tained such  results  as abundantly confirm
the previous determination of Lavoisier.
The following were the products:
    Alcohol of 0.822,     -     171-5
    Carbonic acid,     -    -   94.6
    Nauseous residue,    -      12-0
    Residual yeast,    -    -   40.0

                              318.1
                 Loss,     -    41.9
                              360.0
The latter two ingredients may be disre-
garded in the calculation, as the weight of
the yeast is nearly equivalent to their sum.
  Dividing 171.5 by 3,  we have 57.17 for
the weight of alcohol of 0.822 from 100 of
sugar.  In the  same way we get 31.53 for
the carbonic acid.   Now, spirit of  wine of
0.822 contains 90 per cent of absolute alco-
hol.  Whence,  we find 51.453 for the quan-
tity of absolute alcohol by Thenard's ex-
periment; being a perfect accordance with
the theoretical deductions of M. Gay-Lus-
sac, made at a subsequent period.
        Hy             Ry        By
  M. Lavoisier.   M. Thenard.  Theory.
From 100 sugar.  From 100 do.
Abs. alco. 50.776   51.453      51.55
The coincidence of these  three   results
seems perfectly decisive.
  In  determining the density of absolute
alcohol, M. Gay-Lussac had occasion to ob-
serve, that when alcohol is mixed with wa-
ter, the density of the vapour is  exactly
the mean between the density of the alco-
holic vapour, and that  of the aqueous va-
pour,  notwithstanding  the affinity which
tends to  unite  them.   An important infe-
rence flows from this observation.  The ex-
periments of M. de Saussure, as corrected
by M. Gay-Lussac's theory of volumes, de-
monstrate, that the absolute alcohol which
they  employed contains no separable por-
tion of water,  but what is essential to the
existence of the liquid alcohol.  Had any
foreign water been present, then the speci-
fic gravity of the alcoholic vapour would
have been proportionally  diminished; for
the vapour of water is less dense than that
 of alcohol, in  the ratio of 1 to more than
 2J.  But since the sp.  gravity of alcoholic
 vapour is precisely that which would re-
 sult  from the  condensed union of one vo-
 lume vapour of carbon, one volume of hy-
 drogi n, and half a volume  of oxygen,  it
 seems  absurd  to talk of such  alcohol still
 containing 8.3 per cent of water.
    The writer of a long article on  brewing,
 in the supplement to the 5th edition of the
 Encyclopaedia  Britannica, makes  the fol-
 lowing remarks in discussing M. Thenard's
 researches on  fermentation.   " Now, alco-
 hoi of the  specific  gravity 0.822  contains
 one-tenth of its weight of water, which can
be separated from it;  and if we suppose
with Saussure, that absolute alcohol con-
tains 8.3 per cent  of water, then the pro-
ducts of sugar decomposed by fermenta-
tion, according  to Saussure's (Thenard's
he means) experiments, are as follows:
       Alcohol,     -    -    47.7
       Carbonic acid,    •    35.34

                            83.04
Or in 100 parts,
       Alcohol,     -    -    57.44
       Carbonic acid,    -    42.56
                           100.00
  " This result approaches so  nearly to
that of Lavoisier, that there is reason to
suspect that the coincidence is more than
accidental."  p. 480.
  This  insinuation against the integrity of
one of the first chemists in France, calls
for reprehension.  But farther, M. Gay-
Lussac's account of the  nature  of alcohol
and its vapour was published a  considera-
ble time before the article brewing appear-
ed.  Indeed our author copies a considera-
ble part of it, so that the above error  is
less excusable.
  The ferment or yeast is a substance which
separates under the form of flocculi, more
or less  viscid, from all the juices and infu-
sions which experience the vinous fermen-
tation.  It is commonly procured from the
beer manufactories, and is hence called the
barm of beer.  It may be easily dried, and
is actually exposed for sale in Paris under
the form of a  firm  but slightly cohesive
paste, of  a  grayish-white  colour.   This
pasty barm, left to itself in a close vessel,
at a temperature of from 55° to 70°, is de-
composed, and undergoes in some days the
putrid fermentation.  Placed in contact, at
that temperature, with oxygen  in ajar in.
verted over mercury, it absorbs this gas in
some hours, and there is produced carbo-
nic acid and a little water.  Exposed  to a
gentle heat, it loses more than two-thirds
of its weight, becomes dry, hard, and brit-
tle, and may in this state be preserved for
an indefinite time.  When it is more high-
ly heated, it  experiences a complete de-
composition, and furnishes all the products
which usually result from the  distillation
of animal substances.
   It  is  insoluble  in  water and  alcohol.
 Boiling water speedily  deprives it of its
power  of readily exciting fermentation.—
 In fact, if we plunge the solid yeast into
 water for ten or twelve minutes, and place
 it afterwards in contact with a saccharine
 solution, this exhibits no symptom of fer-
 mentation for a long period.  By that heat,
 the ferment does not seem to lose any of its
 constituents, or  to  acquire  others.  Its
 habitudes with acids and alkalis have not
 been well investigated.   From Thenard's 
FER                                  FIB
 researches, the  fermenting principle in
 yeast seems to be of a caseous or glutinous
 nature.
   It is to the gluten that wheat flour owes
 its property of making a fermentable dough
 with  water.  This  flour paste may indeed
 be regarded as merely a viscid  and elastic
 tissue of gluten, the  interstices of which
 are filled with starch, albumen, and sugar.
 We know  that it is from the gluten, that
 the dough  derives its property of rising on
 the admixture of leaven.  The leaven act-
 ing on the sweet principle of the wheat,
 gives rise  in succession to the  vinous and
 acetous fermentations, and of consequence
 to alcohol, acetic and carbonic acids.  The
 latter gas  tends to fly off, but the gluten
 resists its  disengagement, expands like a
 membrane, forms a multitude of little cavi-
 ties, wrhich give lightness and  sponginess
 to the bread.  For the want of  gluten, the
 flour of all those grains  and roots which
 consist  chiefly of starch are not  capable
 of making  raised bread, even with the ad-
 dition of leaven or yeast.  There does not
 appear to be any peculiar fermentation to
 which the  name panary should be given.*
   When it is required to preserve ferment-
 ed liquors in the state produced  by  the
 first stage  of fermentation, it  is usual to
 put them into casks before the vinous pro-
 cess is  completely  ended;  and in  these
 closed vessels a change very slowly con-
 tinues to be made  for many months, and
 perhaps for some years.
   But if the fermentative process be suffer-
 ed to proceed in open vessels,  more espe-
 cially if the temperature be raised to 90 de-
 grees, the acetous fermentation comes on.
 In this, the oxygen of the atmosphere is
 absorbed; and the more speedily in  propor-
 tion as the  surfaces of the liquor are often
 changed by lading it from  one vessel to
 another.  The usual method consists in ex-
 posing the fermented liquor to the air in
 open  casks, the bunghole of which is co-
 vered with a tile to prevent the entrance of
 the rain.   By the  absorption  of  oxygen
 which takes place, the inflammable  spirit
 becomes converted into an acid. If the li-
 quid be then exposed to distillation, pure
 vinegar comes over instead of ardent spirit.
  When  the spontaneous  decomposition
 is suffered  to proceed beyond the acetous
 process, the vinegar  becomes  viscid and
foul;  air  is emitted  with   an offensive
 smell; volatile alkali flies off; an earthy sedi-
ment  is deposited; and the  remaining li-
 quid, if any, is mere water.  This is the
putrefactive process.
  The fermentation by which certain co-
louring matters  are separated from vege-
tables, as in the preparation of woad and
indigo, is carried much farther, approach-
ing the putrefactive stage.
  It is not clearly ascertained what the yeast
 or ferment performs in this operation.  It
 seems probable, that the fermentative pro-
 cess in considerable masses would be car-
 ried  on progressively from  the  surface
 downwards;  and would  perhaps, be com-
 pleted  in one part before it had perfectly
 commenced in another, if the yeast, which
 is already in a state  of fermentation, did
 not  cause the process  to begin in every
 part  at once.   See Bread,  Distilla-
 tion, PUTRE FACT ION, ALCOHOL, WlNE,
 Acid (Acetic), Vegetable Kingdom.
   * Ferrocyanates.  See Acid (Fer-
 roprussic).*
   *  Ferrocyanic  Acid.    See Acid
 (Ferroprussic).*
   * Ferroprussic  Acid, and Ferro-
 prussiates.  See  Acid  (Ferroprus-
 sic).*
   *  Ferruretted Chyaxic Acid.  The
 same as Ferroprussic*
   *  Fetstein.  Elaolite.*
   *  Fibrin.   A peculiar  organic  com-
 pound  found  both  in vegetables and ani-
 mals.   Vauquelin discovered it in the juice
 of the papaw tree.  It is a soft solid,  of a
 greasy  appearance,  insoluble  in  water,
 which  softens in the air, becoming viscid,
 brown,  and  semi-transparent.    On  hot
 coals it melts, throws out greasy drops,
 crackles, and evolves  the smoke and odour
 of roasting meat. Fibrin is procured, how-
 ever, in its most characteristic  state from
 animal matter.  It exists in chyle; it en-
 ters into the composition of blood.  Of it,
 the chief part of muscular flesh is formed;
 and hence it may be regarded as the most
 abundant constituent of the soft  solids  of
 animals.
   To  obtain it, we may beat blood,  as it
 issues  from  the veins, with a  bundle of
 twigs.   Fibrin soon attaches itself to each
 stem, under the form  of long reddish fila-
 ments, which become colourless by wash-
 ing them with cold*water. It is solid, w hite,
 insipid, without smell, denser than  water,
 and incapable of effecting the  hue of lit-
 mus or violets.  When moist it possesses a
 species of elasticity; by desiccation it be-
 comes yellowisft, hard, and brittle.  By dis-
 tillation we can extract from it much  car-
 bonate  of ammonia, some acetate, a fetid
 brown  oil, and gaseous products; while
 there remains in the retort a very volumi-
 nous charcoal, very brilliant, difficult of in-
 cineration, which leaves after combustion,
 phosphate of lime, a little  phosphate of
 magnesia, carbonate of lime, and carbonate
 of soda.
  Cold water has no action on fibrin. Treat-
 ed with boiling water, it is so changed as
 to lose  the property of  softening and dis-
 solving  in  acetic acid.   I he liquor filter-
 ed from it, yields precipitates  with  infu-
 sion of galls,' and the residue is white, dry,
hard, and of an agreeable taste. 
FIB
FIL
  When kept for some time  in alcohol of
0.810, it gives rise to an adipocerous mat-
ter, having a strong and disagreeable odour.
This matter remains dissolved in the alco-
hol,  and may be  precipitated by water.
Ether makes it undergo  a similar altera-
tion, but more slowly.  When digested m
weak muriatic acid, it evolves a little azote,
and a compound  is  formed, hard, horny,
and which washed repeatedly with water,
is transformed into another gelatinous com-
pound.  This seems  to be a  neutral muri-
ate, soluble in hot  water; whilst the first is
an acid muriate, insoluble even in boiling
water.  Sulphuric acid,  diluted  with six
times its weight of water, has similar ef-
fects.  When not too concentrated, nitric
acid has a very different action on fibrin.
For example, when its sp. gr. is 1.25, there
results from it at first a disengagement of
azote,  while the fibrin becomes covered
with fat, and the liquid turns yellow.  By
digestion  of 24 hours, the whole fibrin is
attacked,  and converted into a pulverulent
mass of a lemon-yellow colour, which seems
to be composed of  a mixture of fat and
fibrin, altered and intimately combined
with the malic and nitric or nitrous acids.
In fact, if we put this mass  on a filter, and
wash it copiously with water, it  will part
with a portion of its acid, will preserve the
property  of reddening  litmus,  and will
take an orange hue   On treating it after-
wards with  boiling alcohol,  we dissolve
the fatty matter; and putting  the remain-
der  in contact with chalk  and  water, an
efflorescence will  be occasioned by the
escape of carbonic acid, and malate or ni-
trate of lime will remain in solution.
  Concentrated acetic acid  renders fibrin
 soft at ordinary temperatures, and converts
 it by the  aid of heat into a jelly,  which  is
 soluble in hot water, with the disengage-
 ment of a small quantity of azote.   This
 solution is colourless, and possesses  little
 taste.  Evaporated to dryness, it leaves a
 transparent  residue, which reddens litmus
 paper, and which cannot be dissolved even
 in boiling water, but by the medium  of
 more acetic acid   Sulphuric, nitric, and
 muriatic acids, precipitate the animal mat-
 ter, and form acid  combinations.  Potash,
 soda, ammonia, effect likewise the  preci-
 pitation of this matter, provided we do not
 use too great an excess of  alkali; for then
 the precipitated  matter would  be  redis.
  solved.   Aqueous potash and soda  gradu-
  ally dissolve fibrin in the cold, without oc-
  casioning any  perceptible  change  in  its
  nature; but  with  heat they decompose it,
  giving birth to a quantity of ammoniacal
  gas, and other usual animal products.   Fi-
  brin does not putrefy speedily  when kept
  in water. It shrinks on exposure to a con-
  siderable heat, and emits the smell of burn-
  ing horn. It is composed, according to the
analysis of MM. Gay-Lussac and Thenard,
of Carbon,   53.360
   Azote,    19934
   Oxygen,  19.685") 22.14 water
   Hydrogen,  7.0213  4.56 hydrogen.*
   • Fibrolite.  Colours white and gray;
crystallized in rhomboidal prisms, the an-
gles of whose planes  are 80° and 100°.  It
is glistening internally. Principal fracture
uneven.  Harder than quart*.  Sp. gr. 3.214.
Its constituents are alumina  58.25, silica
38, iron and loss 3.75.  It is found in the
Carnatic.—Jameson.*
   * Figurestone.  See Bildstein.*
   Filtration.   An operation, by means
of which a fluid is mechanically separated
from consistent particles merely mixed with
it.  It does not differ from straining.
   An  apparatus fitted up for  this purpose
is called a filter.  The form of this is  va-
rious, according to the intention of the ope-
rator.  A  piece of tow, or wool, or cotton,
stuffed into the pipe  of a funnel, will pre-
vent the passage of grosser particles, and
by that means render the   fluid  clearer
which comes through.  Sponge is still more
effectual.   A strip of linen rag wetted and
hung  over the  side of a vessel containing
 a fluid, in such a  manner as that one end
of the rag may be immersed in the fluid,
 and the other end  may remain without,
 below the surface, will act as a syphon, and
 carry over the clearer portion.  Linen or
 woollen stuffs  may either be fastened over
 the mouths of proper vessels, or fixed to
 a frame, like a sieve,  for the purpose of
 filtering.  All these  are more commonly
 used  by cooks and  apothecaries than by
 philosophical chemists, who, for the most
 part,  use  the paper called cap-paper, made
 up without size.
   As the  filtration of considerable quanti-
 ties of  fluid could not be effected at once
 without breaking the filter of paper,  it is
 found requisite to use a linen cloth, upon
 which the paper  is applied and supported.
   Precipitates and other pulverulent mat-
 ters are collected more speedily by filtra-
 tion  than  by  subsidence.  But there are
 many chemists who disclaim the use of
 this  method,  and avail themselves of the
 latter only, which is  certainly more accu-
 rate, and liable to no objection, where the
 powders  are such as will admit of edulco-
 ration and drying in the open air.
    Some fluids, as turbid water, may be pu-
  rified by  filtering through  sand.  A large
  earthen funnel,  or  stone bottle with the
  bottom beaten out, may have its neck loose-
  ly  stopped with  small stones, over which
  smaller may be placed, supporting layers of
  gravel increasing in fineness, and lastly co-
  vered to the depth  of a few inches  with
  fine  sand, all thoroughly cleansed by wash-
  ing.  This apparatus is superior to a filter-
  ing stone, as it will cleanse water in large 
FLI
FLU
quantities,  and may readily  be renewed
when the passage is obstructed, by taking
out and washing the upper stratum of sand.
  A  filter for corrosive liquors may be con-
structed, on the same principles, of broken
and pounded glass.
  Fire.  See Caloric and Combustion.
  •Fire-damp.   See  Combustion and
Carburetted Hydrogen.*
  * Fish-scales  are composed of alter-
nate  layers of membrane  and phosphate
of lime.*
  * Fixed Air.   Carbonic acid gas.*
  Fixity. The property by  which  bodies
resist the action of heat, so as not to rise
in vapour.
  * Flake-white.  Oxide of bismuth.*
  Flame.  See Combustion.
  •Flesh. The muscles of animals. They
consist chiefly of  fibrin,  with albumen, ge-
latin, extractive, phosphate of soda, phos-
phate of ammonia, phosphate  and  carbo-
nate of lime,  and sulphate of potash.   See
Muscle.*
   •Flint.   Colour generally gray,  with
occasionally zoned and striped delineations.
Massive, in rolled pieces, tuberose and per-
forated.  It rarely occurs in supposititious,
hollow,  pyramidal or  prismatic crystals.
It occurs  often in extraneous shapes, as
echinites, coralites, madreporites, fungites,
belemnites, mytilites, &c; sometimes in la-
mellar concretions. Internal lustre glim-
mering. Fracture conchoidal.  Fragments
 sharp-edged.   Translucent.  Hitler than
quartz.  Easily frangible. Sp. gr. 2.59. In-
fusible without addition, but whitens and
becomes opaque.   Its  constituents  are 98
 silica, 0.50 lime, 0.25 alumina, 0.25 oxide
of iron, 1.0 loss.  When two pieces of flint
 are  rubbed together in the dark, they phos-
 phoresce,  and emit a peculiar smell.
   It occurs in primitive, transition, secon-
 dary, and  alluvial mountains.  In the first
 two, in metalliferous and agate veins.  In
 secondary countries it is found in pudding-
 stone, limestone, chalk, and amygdaloid.
 In chalk it occurs in  great  abundance in
 beds  These seem to have been both formed
 at the same time.  Werner,  however, is of
 opinion, that  the  tuberose and many  other
 forms, have been produced by infiltration.
 In Scotland, it occurs  imbedded in secon-
 dary limestone in the  island of Mull, and
 near Kirkaldy in Fifeshire.  In England, it
 abounds in alluvial districts in the form of
 gravel, or is  imbedded  in chalk.  In Ire-
 land it  occurs  in considerable quantities
 in secondary  limestone.  It is found in most
 parts of the world. Its principal use is for
 gun flints, the mechanical  operations of
 which manufacture, are fully  detailed by
 Brongniart. The best flint for this purpose,
 is the yellowish-gray.   It  is an ingredient
 in pottery, and chemists use it for mortars.*
   •Fljsty-slate.  Of this mineral there
are two kinds, common flinty-slate, and Ly-
dian  stone.
  1.  Common.  Colour ash-gray, with other
colours, in flamed, striped, and spotted de-
lineations.  It is often traversed by quartz
veins.  Massive, and in lamellar concretions.
Internally it is  faintly glimmering.  Frac-
ture  in the great slaty, in the small splin-
tery.   Translucent.  Hard.  Uncommonly
difficultly frangible.  Sp. gr. 2.63. It occurs
in beds, in clay-slate and gray-wacke; and in
roundish and angular masses in sandstone.
It is found in different parts of the great
tract of clay-slate and gray-wacke which
extends from St. Abb's-head to Portpatrick;
also in the Pentland hills near Edinburgh.
   2. Lydian  stone.   Colour  grayish-black,
which passes into velvet-black.  It occurs
massive, and rolled in pieces with  glisten-
ing surfaces.  Internally it is glimmering.
Fracture even.  Opaque.  Less hard than
flint.  Difficultly frangible.  Sp. gr. 2.6.  It
occurs very frequently along with common
flinty-slate in beds in clay-slate. It is found
near Prague and  Carlsbad in Bohemia,  in
Saxony, the Hartz, and at the Moorfoot and
Pentland hills near Edinburgh. It is some-
times  used as a touchstone for ascertaining
the purity of gold and silver. See Assay.*
   *  Floatstone.  A  sub-species of the
indivisible  quartz of Mohs.  Spongiform
quartz of Jameson.   Colour white of vari-
ous  shades.  In porous, massive, and tube-
rose forms.  Internally it is dull. Fracture
 coarse earthy.  Feebly translucent on the
 edges.  Soft, but its minute particles are
 as hard as quartz.   Rather brittle.  Easily
 frangible.  Feels meagre and rough, and
 emits a grating  noise,  when  the  finger is
 drawn across it.  Sp. gr. 0.49.  Its consti-
 tuents are silica  98, carbonate of lime 2.—
 Vauq.  It occurs encrusting flint, or in im-
 bedded masses in a secondary limestone at
 St. Ouen near Paris.—Jameson.*
   Flour.  The powder ofthe gramineous
 seeds.  Its use as food is well known.  See
 Bread.
   Flowers.  A general appellation used
 by the elder chemists, to denote  all such
 bodies as have received a pulverulent form
 by sublimation.
   Flowers of Vegetables.  Dr. Lewis
 in his notes on Neumann's Chemistry, gives
 a cursory account  of  many experiments,
 made with a view to ascertain how far the
 colour of vegetable flowers might  prove of
 use to the dyer.   He found very few capa-
 ble of being applied to valuable purposes.
   * Fluates.  Compounds of the salifia-
 ble bases with fluoric acid.*
   Fluidity.  The state of bodies when
 their parts are very readily moveable in all
 directions with respect to each other. See
 Caloric
   * FluoboraTes.  Compounds of fluo-
 boric acid with the salifiable bases.* 
FLU                                 FOR
    * Fluor.  Octohedral fluor of Jameson.
  It is divided into three sub-species; com-
  pact fluor, foliated fluor, and earthy fluor.
    1. Compact.  Colours, greenish-gray and
  greenish-white.  Massive.  Dull or feebly
  glimmering.   Fracture  even.   Fragments
  sharp-edged.  Translucent.  Harder than
  calcareous spar, but not  so hard as apatite.
  Brittle, and easily  frangible.   Sp. gr. 3.17.
  It is found in veins, associated with fluor
  spar, at Stolbergin the Hartz.
    2. Foliated. Colours, white,yellow, green,
  and blue.  Green cubes appear with white
  angles.   Massive, disseminated, and in dis-
  tinct concretions.  Crystallized in  cubes,
  perfect orvariously truncated and bevelled;
  in the rhomboidal dodecahedron, and the
  octohedron, or double four-sided pyramid.
  The crystals are generally placed on one
  another, and form druses;  but are  seldom
  single.   Surface smooth and splendent, or
 drusy and rough. Internal lustre, specular-
 splendent, or shining vitreous.  Cleavage,
 fourfold  equiangular,  parallel  with the
 planes of an octohedron.  Fragments octo-
 hedral or tetrahedral. Translucent to trans-
 parent.   Single refraction.   Harder  than
 calcareous spar, but not  so hard as apatite.
 Brittle, and easily frangible.  Sp. gr. 3.15.
 Before the blow-pipe it generally decrepi-
 tates, gradually loses its colour and trans-
 parency,  and melts without addition into a
 grayish-white glass.  When two fragments
 are rubbed together,  they become lumi-
 nous in the dark.  When gently heated, it
 phosphoresces with a blue and green light.
 By ignition it loses its phosphorescent pro-
 perty.  The violet blue variety from Nert-
 schinsky, called chlorophane. when placed
 on glowing coals, does not decrepitate, but
 soon throws out a green light   Sulphuric
 acid evolves from pulverized fluorspar, acid
 fumes which  corrode  glass.  Its constitu-
 ents, by Berzelius, are 72.1 lime, and 27.9
 fluoric acid.   It occurs principally in veins
 that  traverse  primitive, transition, and
 sometimes  secondary rocks.  It has  been
 found only in  four places in Scotland, near
 Monaltree in Aberdeenshire, in gneiss in
 Sunderland, in secondary  porphyry near
 Gourock  in Renfrewshire, and in the island
 of Papastour,  one ofthe  Shetlands.   It oc-
 curs  much more abundantly  in England,
 being found in all the galena veins that tra-
 verse the coal formation in Cumberland and
 Durham;  in secondary or floetz limestone
 in Derbyshire;  and it is the most common
 veinstone in the copper, tin,  and lead veins,
 that  traverse  granite  clay-slate,  &c.  in
 Cornwall  and  Devonshire.   It is also fre-
 quent on  the Continent  of  Europe.   It is
 cut into ornamental forms. It has also been
 used as a flux for ores; whence its  name
fluor.—Jameson.
   3. Earthy fluor.  Colour,  grayish-white
 and violet-blue, sometimes very deep.  It
 occurs generally in crusts investing some
 other mineral.   Dull.  Earthy.  Friable. Its
 constituents are the same as the preceding.
 It occurs in veins along with fluor spar at
 Beeralstone in Devonshire; in Cumberland,
 in Saxony, and Norway.*
   * Fluoric  Acid.   See Acid  (Fluo-
 ric.)*
   •Fluorine.  The imaginary radical of
 the above acid.*
   * Flttosilicates. See Acid (Fluosi.
 licic).*
   Flux.  A general term made use of to
 denote any substance or mixture added to
 assist the fusion of minerals.  In the large
 way, limestone and fusible spar are used as
 fluxes.  The fluxes made  use of in assays,
 or philosophical experiments, consist usu-
 ally of alkalis, which render the earthy mix-
 tures fusible, by converting them into glass;
 or else glass itself in powder.
  Alkaline fluxes are either the crude flux,
 the white flux, or the  black flux.   Crude
 flux is a mixture of nitre and tartar, which
 is put into the crucible with the mineral
 intended to  be fused.   The detonation of
 the nitre with  the  inflammable matter of
 the tartar, is of service in some operations;
 though generally it is attended with incon-
 venience on account of  the swelling of the
 materials, which may throw them  out of
 the vessel, if proper care be not taken either
 to throw in only a little  of the mixture at a
 time, or tp provide a large  vessel.
  Whitewflux is  formed by projecting  a
 mixture of equal parts of nitre and tartar, by
 moderate portions at a time, into an ignited
 crucible.  In the  detonation which ensues,
 the  nitric acid is decomposed and flies off
 with  the tartaric acid, and the remainder
 consists ofthe potash in a state of conside-
 rable purity.   This  has been called fixed
 nitre.
  Black  flux differs from the preceding, in
 the proportion of its ingredients.  In this
 the weight of the tartar is double that of
 the nitre; on which account the combustion
 is incomplete, and a considerable portion
 of the  tartaric acid is decomposed by
the  mere heat, and leaves a quantity of
coal behind, on which the black colour de-
pends.  It is used where metallic ores are
intended to  be reduced, and effects this
purpose, by combining with the oxygen of
the oxide.
  The advantage of M. Morveau's reducing
flux, seems to depend on its containing no
excess of alkali.  It is made of eight parts
of pulverized glass, one of  calcined borax,
and half a part of powder of charcoal. Care
must be taken to use a glass which con-
tains no lead.   The white  glasses contain
in general a large proportion, and the green
bottle glasses are not perhaps entirely free
from  it.
  Forge Furnace.  The forge furnace 
FUL
FUL
consists of a hearth, upon which a fire may
be made, and urged by the action of a large
pair of double bellows, the nozzle of which
is inserted through a wall or parapet con-
structed for that purpose.
  Black-lead pots,  or  small  furnaces  of
every desired form, may be placed, as oc-
casions require, upon the hearth; and the
tube of the  bellows being inserted into a
hole in the  bottom of the furnace, it be-
comes easy to urge the heat to almost any
degree required.
  •Formations.  See Geology.*
  * Formiates.  Compounds  of formic
acid with the salifiable bases.*
  * Freezing.  See Caloric, and Con-
gelation.*
  * Fossil Copal, or Highgate resin. Its
colour is pale muddy yellowish-brown.  It
occurs in irregular roundish pieces.   Lus-
tre resinous.   Semi-transparent.  Brittle.
Yields easily to the knife.  Sp.  gr.  1.046.
When heated,  it gives out a resinous aro-
matic odour, melts into a limpid fluid, takes
fire at a lighted candle, and burns entirely
away  before the blow-pipe.   Insoluble in
potash ley.  Found in the bed of blue clay
at Highgate near London.  Aikin,s Minera-
logy*
  Frankincense.  See Olibanum.
  French  Berries.  The fruit of the
Rhamnus infectorius, called by the French
graines <PAvignon.  They give a pretty good
yellow colour,  but  void of permanency.
When used  for dyeing, the  cloth is pre-
pared in the same manner as for weld.
  Friesland Green.  Ammoniaco-mu-
riate of copper, the same with Brunswick
green.  See Copper.
  Frits.  The materials of glass are first
mixed together, and then exposed to cal-
cination by  a  degree of heat not sufficient
to melt them.  The mass is then  called
fritt.
   Fruits of Vegetables.  Sap Green
is prepared  from the berries of buckthorn,
and Annotto is obtained from the  pelli-
cles of the seeds of an  American tree. See
the words.
  Fuliginous.  Vapours which possess
the property of smokernamely, opacity, and
the disposition to apply themselves to sur-
rounding bodies in the form of a dark co-
loured powder.
  * Fullers' Earth.  Colour greenish-
white, and other shades of green. Massive.
Dull.   Fracture uneven.  Opaque.  Shin-
ing and resinous in the streak.  Very soft.
Sectile.  Scarcely  adheres to the tongue.
Feels greasy.   Sp. gr.  1.7 to 2.2. It falls
into a powder  with  water,  without the
crackling noise which accompanies the dis-
integration of bole.  It melts into a brown
spongy scoria before the blow-pipe.   Its
constituents are 53 silica, 10 alumina, 1.25
magnesia, 0.50 lime, 0.10 muriate of soda,
trace of potash, oxide of iron 9.75, water
24.—Klaproth. Bergmann found 24 alumina,
and only 0.7 oxide of iron.  In England it
occurs in  beds, sometimes above, some-
times below, the chalk formation; at Ross-
wein  in Upper Saxony, under  strata of
greenstone slate; and in different places in
Germany it is found immediately under the
soil.  The best is found in  Buckingham-
shire and  Surry.  When good,  it has a
greenish-white, or  greenish-gray  colour,
falls into powder in water, appears to melt
on the tongue  like butter, communicates a
milky hue to water, and deposites very little
sand when mixed with boiling water.  The
remarkable detersive property on  woollen
cloth,  depends  on  the alumina,  which
should be at least one-fifth  of the whole,
but not much more than one-fourth, lest it
become too tenacious.—Jameson*
  Fulminating and   Fulmination.
In a  variety of chemical combinations, it
happens, that one or more  of the princi-
ples assume the elastic state with such ra-
pidity, that the stroke against the displa-
ced air produces a loud noise. This is call-
ed fulmination, or much more  commonly
detonation.
  Fulminating gold, and fulminating pow-
der, are the most common substances of
this kind, except gunpowder. For the lat-
ter of these, see the article Gunpowder.
The fulminating powder is made by tritu-
rating in a warm mortar, three parts by
weight of nitre, two of carbonate of pot-
ash, and  one  of flowers of sulphur.  Its
effects, when fused in a ladle, and then set
on fire, are very great.   The whole of the
melted fluid explodes with an  intolerable
noise, and the ladle is commonly  disfi-
gured, as if it had received a strong  blow
downwards.
   If a solution of gold be precipitated by
ammonia, the product will  be fulminating
gold.  Less than  a grain of this, held over
the flame of a candle, explodes with a very
sharp and loud noise.    This precipitate,
separated by filtration,  and washed,  must
be dried without  heat, as it is liable to ex-
plode with no great increase of tempera-
ture; and it must not be put into a bottle,
closed with a glass stopple, as the friction
of this would  expose the operator to the
same danger.
   Fulminating silver may be made by pre-
cipitating a solution of nitrate of silver by
lime-water, drying the  precipitate by ex-
posure to the air for two or three days, and
pouring on it liquid ammonia.   When it is
thus  converted  into a black powder, the
liquid must be poured off", and the powder
left to dry in  the air.   It detonates  with
the gentlest heat, or even with  the slight-
est friction, so that it must not be removed
from the vessel in which it is made.   If a
drop of water fall upon it,  the  percussion 
FUL                                  FUS
 will cause it to explode. It was discovered
 by Berthollet.
   Brugnatelli made a fulminating silver by
 powdering a  hundred grains of nitrate of
 silver, putting the powder into a beer glass,
 and pouring on it, first an ounce of alcohol,
 then as  much concentrated nitrous  acid.
 The mixture  grows hot, boils, and an ether
 is visibly formed, that changes into gas.  By
 degrees  the  liquor  becomes  milky  and
 opaque, and is filled with small white clouds.
 When all the gray powder has taken  this
 form, and the liquor has acquired a consis-
 tency, distilled water must  be added im-
 mediately to  suspend the ebullition,  and
 prevent the matter from being redissolved,
 and  becoming a mere  solution  of silver.
 The white precipitate is then to be collec-
 ted on a  filter, and dried.   The  force of
 this powder greatly exceeds that  of fulmi-
 nating mercury.  It detonates in a tremen-
 dous manner, on being scarcely touched
 with a glass tube, the extremity  of which
 has been  dipped  in concentrated sulphuric
 acid.   A  single grain, placed on a lighted
 coal, makes a deafening report.  The same
 thing happens, if it be placed on a bit of
 paper  on  an electric  pile,  and a spark
 drawn from it.
  Fulminating mercury was discovered by
 Mr. Howard.  A hundred grains  are to be
dissolved with heat in an ounce and half by
 measure of nitric acid. The solution, when
cold, is to be  poured on two  ounce  mea-
 sures of alcohol, and heat applied till  an
 effervescence is excited.  As soon as the
precipitate is  thrown down, it must be col-
lected  on a filter, that  the  acid  may  not
react on it; washed, and dried by a  very
gentle  heat. It detonates with a very little
heat or friction.
  Three  parts of chlorate of potash,  and
one of sulphur, triturated in a  metal  mor-
 tar, cause numerous successive detonations,
 like the cracks of a whip, the reports of a
pistol,  or the  fire of musketry, according
to the rapidity and force of the  pressure
employed.  A few grains,  struck with a
hammer on an anvil, explode with a noise
 like that of a musket, and torrents of pur-
 ple light appear round it.   Thrown into
 concentrated  sulphuric acid, it takes fire,
 and burns with a white flame, but without
noise.
  Six parts of the chlorate, one of sulphur,
 and one of charcoal, detonate by the same
 means, but more strongly, and with a red-
der flame.
  Sugar, gum, or charcoal mixed with the
 chlorate, and fixed or volatile oils, alcohol,
 or ether,  made into a paste  with  it,  deto-
 nate very strongly by the stroke,  but not
 by trituration.  Some of them take fire,
 but slowly and by degrees, in the sulphu-
 ric acid.
  All these mixtures, that detonate by the
 stroke, explode  much more loudly if pre.
viously wrapped up in double paper.
  • Fulminations of the most violent kind
require the agency of azote or nitrogen; as
we see not only in its compounds with the
oxides of gold, silver, and platina; but still
more remarkably in its chloride and iodide.
See Nitrogen.*
  Fuming Liquor.  The fuming liquors
of Boyle and  Libavius have  been long
known.  To prepare that of Boyle,  which
is a hydroguretted sulphuret of ammonia,
three parts of lime fallen to powder in the
air, one of muriate of ammonia, and one of
flowers of sulphur, are to be mixed in  a
mortar, and distilled with  a gentle  heat.
The yellow liquor, that  first comes  over,
emits fetid  fumes.   It  is  followed  by  a
deeper coloured fluid, that is not fuming.
  The fuming liquor of Libavius is  made
by amalgamating tin  with half its weight
of mercury, triturating this amalgam with
an equal weight of corrosive muriate  of
mercury, and distilling by a gentle heat.  A
colourless fluid at first passes  over:  after
this, a thick vapour is thrown out  at one
single jet with a sort of  explosion, which
condenses into a transparent liquor, that
emits copious, white, heavy, acrid fumes
on exposure to the air.   In a closely  stop-
ped bottle, no fumes  from it are percepti.
ble;  but  needle-shaped   crystals   form
against the  top  of the bottle,  so as fre-
quently to close the aperture.
  Cadet's fuming liquor is prepared by
distilling equal parts of  acetate  of potash
and arsenious acid, and receiving the pro-
duct into glass bottles, kept cool by a mix-
ture of ice and salt.   The liquor produced,
emits a very dense,  heavy,  fetid noxious
vapour, and inflames spontaneously in the
open air.
  * Fungates. The saline compounds of
a peculiar  acid, which M. Braconnot has
lately extracted from mushrooms.*
  * Fungin.  The  fleshy  part of mush-
rooms, deprived by alcohol and water of
every thing soluble.  It seems to be a mo-
dification of woody fibre.*
  Furnace.  See Laboratory.
  Fusibility.   That property by which
bodies assume the fluid state.
  Some chemists have asserted that fusion
is simply a solution in caloric; but this opi-
nion  includes too many yet  undecided
questions, to be hastily adopted.
  Fusion.  The act of fusing.  Also the
state of a fused body.
  Fustet.   The wood of the rhus cotinus,
or Venus's sumach, yields, a fine orange
colour, but not at all durable.
  Fusric,  or Yellow  Wood.   This
wood, the mortis tinctoria, is a native ofthe
West Indies.  It affords  much  yellow co-
louring matter, which is very permanent.
  The yellow  given by fustic without any 
GAL                                 GAL
mordant is dull, and brownish, but stands   is, that the yellow of fustic • inclines more
well.   The mordants employed with weld   to orange than that of weld; and, as it
act on it in a similar manner, and by their   abounds more in colouring matter, a less
means the colour is rendered more bright   quantity will suffice.
and fixed.  The difference  between tiiem
G
•|^ABBRON\T.  Scapolite.*
 \JT  * Gadolinite.   Prismatic gado-
linite.—Mohs.
  Its colours are velvet-black, and black of
various shades.   Massive and dissemina-
ted.  Rarely  crystallized.   Its primitive
figure  seems  to be "an oblique four-sided
prism, inwhich  the obtuse angle is nearly
110°.  This prism sometimes occurs  with
six lateral planes.  Lustre resinous inclin-
ing  to  vitreous.  Fracture conchoidal.
Very faintly  translucent on the thinnest
edges, and then it appears blackish-green.
Harder  than feldspar,  but  softer  than
quartz. Streak greenish-gray. Brittje; dif-
ficultly frangible.  When pure it does not
affect'the magnet.  Sp. gr. 4.0 to 4.2. It in-
tumesces very much before the blow-pipe,
and at length melts into an imperfect slag,
which is magnetical.   It loses its colour in
nitric acid, and  gelatinizes.   Its constitu-
ents are 25.8 silica, 45  yttria, 16.69 oxide
of ceriumj 10.26 oxide of iron, 0.60  vola-
tile matter.—Berzelius.   It occurs along
with yttrotantalite at Ytterby in Sweden, in
beds of a coarse  granular  red feldspar,
which are situated in mica slate; at Finbo,
near Fahlun also in  Sweden, in a coarse
granular granite, along  with pyrophysalite
and tin-stone.—Jameson.*
   * Gahnite.  Automalite or octohedral
corundum.*
   • Gallitxinite.  Rutile.  An ore of
 titanium.*
   Galbanum  exudes from the bubongal-
 banum.  This juice comes over in  masses,
 composed of white, yellowish,  brownish-
 yellow,  and brown tears, unctuous to  the
 touch, softening betwixt the fingers; of a
 bitterish,  somewhat  acrid, disagreeable
 taste, and a  very  strong smell; generally
 full of  bits  of stalks,  leaves, seeds  and
 other foreign matters.
   Galbanum  contains more of a resinous
 than gummy matter: one pound yields with
 alcohol upward of nine ounces and a  half
 of resinous extract; but the gummy extract
 obtained by water from the same quantity,
 amounts only to about three ounces.   The
 resin is hard,  brittle,  insipid,  and inodo-
 rous: the gummy extract has somewhat of
 a nauseous relish, but could not be distin-
 guished to be  a preparation of galbanum.
 The whole smell, flavour, and specific taste
 of this juice,  reside  in an essential oil,
    Vol. II.
which arises in distillation both with water
and spirit, and gives a strong impregnation
to both:  from a pound of galbanum are
obtained,  by distillation  with water, six
drachms of actual oil, besides what is re-
tained by the water.  In this  respect  gal-
banum agrees with  asafcetida, and differs
from ammoniacum.
  Galena.  The black ore of lead.
  Gall  of Animals.  See  Bile.
  Gall-stones.   Calculous concretions
are not unfrequently formed in the gall
bladder, and sometimes   occasion  great
pain in their  passage through  the ducts
into the duodenum, before they  are evacu-
ated.   Of these stones there  are four dif-
ferent kinds.
   i. The first has a white colour, and when
broken, presents crystalline plates, or striae,
brilliant and white  like mica, and having a
soft greasy feel.. Sometimes  its colour is
yellow or greenish; and it has constantly a
nucleus of inspissated bile. Its sp. gravity
is inferior to that  of water:   Gren found
the specific gravity of one, 0.803.  When
exposed to a heat considerably greater than
that of boiling water, this crystallized cal-
culus softens and  melts,  and crystallizes
again when the temperature is lowered.  It
is altogether insoluble in water; but hot
alcohol dissolves it with facility.  Alcohol,
of the temperature of 167°, dissolves one-
twentieth of its weight of this  substance;
but alcohol, at the  temperature of 60°,
scarcely dissolves any of  it.   As the  alco-
hol cools, the matter is deposited in bril-
liant plates,  resembling   talc or boracic
 acid.  It is soluble  in oil of turpentine.
 When melted, it has the appearance of oil,
 and exhales the smell of melted wax; when
 suddenly heated, it evaporates  altogether
 in a thick smoke.  It is soluble in pure al-
 kalis, and the solution has all the proper-
ties of soap.   Nitric acid also dissolves it;
 but it is precipitated unaltered  by water.
   This matter, which is evidently the same
 with the crystals Cadet obtained from bile,
 and which he  considered  as  analogous  to
 sugar of mHk, has a strong resemblance to
 spermaceti.  Like that substance,  it is  of
 an oily nature, and inflammable; but it dif-
 fers  from  it  in a variety of particulars.
 Since it is contained in bile, it is not diffi-
 cult to see  how it  may crystallize in the
 gall-bladder if it happen  to be more abun-
                         9 
GAL
GAL
  dant than usual; and the consequence must
  be a gall-stone of this species.  Fourcroy
  found a quantity of the same substance in
  the dried human liver.  He called it Adi-
  pocere.
    2. The second species of biliary calcu-
  lus is of a round or polygonal shape, often
  of a gray colour externally,  and  brown
  within.  It is formed of concentric layers
  of a matter which seems to be inspissated
  bile; and there is usually a nucleus  of the
  white crystalline matter at the centre.  For
  the most part, there are many of this spe-
  cies of calculus in the gall-bladder toge-
 ther: indeed  it is frequently  filled with
 them.  The calculi belonging to this spe-
 cies are  often  light and friable, and of a
 brownish-red colour.  The gall-stones  of
 oxen used by painters belong to this spe-
 cies.  These are also adipocere.
   3. The third species of calculi are most
 numerous of all.  Their colour  is often
 deep brown or green; and when broken, a
 number of crystals of the substance  re-
 sembling spermaceti are observable,  mixed
 with inspissated bile.  The calculi belong-
 ing to these three species  are soluble  in
 alkalis, in soap ley, in alcohol,  and in oils.
   4.  Concerning the fourth  species of gall-
 stone, very little is known  with accuracy.
 Dr. Saunders tells us, that-he has met with
 some gall-stones insoluble both in alcohol
 and oil of turpentine, some of which  do
 not flame, but become red, and consume
 to  ashes like  charcoal.  Haller quotes  se-
 veral examples of similar  calculi.   Gall-
 stones  often occur in the inferior animals,
 particularly in cows and hogs; but the bi-
 liary concretions of these animals have not
 hitherto been examined with much atten-
 tion.
   Soaps have been proposed  as solvents
 for these calculi.   The academy of Dijon
 has published the success of a mixture  of
 essence of turpentine and ether.
   Galls.   These  are the protuberances
 produced by the puncture  of an insect on
 plants and trees of different kinds. Some
 of  them are hard, and termed nut-galls;
 others are soft and spongy, and called ber-
 ry-galls, or  apple-galls.  The best are the
 nut-galls ofthe oak, and those brought from
 Aleppo  are preferred.   These are  not
 smooth on  the   surface, but  tubercular,
 small, and heavy; and should have a bluish
 or blackish tinge.
  Deyeux investigated the properties  of
 galls with considerable care; and more late-
 ly Sir H. Davy has examined the same sub-
ject.  The strongest infusion Sir H. Davy
 could obtain at 56° F. by repeated infusion
 of distilled water, on the best Aleppo galls,
 broken  into small pieces, was of the spe-
 cific gravity of 1.068.  Four hundred grains
 of this  infusion, evaporated at a heat be-
low 200", left 53  of solid matter, which
 consisted of about 0.9 tannin, and 0.1 gal-
 lic acid, united to a portion of extractive
 matter.  One hundred grains of the solid
 matter left,  by incineration,  nearly 4},
 which were chiefly calcareous matter, mix-
 ed with a small portion of fixed alkali.
   From 500 grains of Aleppo galls, Sir H.
 Davy obtained, by infusion as above, 185
 grains of solid matter, which  on analysis
 appeared to consist of tannin  130;  muci-
 lage, and  matter  rendered insoluble by
 evaporation, 12; gallic acid, with a little ex-
 tractive matter, 31; remainder, calcareous
 earth and saline matter, 12.
   The use of galls in dyeing is very exten-
 sive, and they are one of the principal in-
 gredients in making ink.   Powdered galls
 made into an ointment  with hog's lard are
 a very  efficacious  application  in piles.
 They are sometimes given internally as an
 astringent; and in the intermittents, where
 the  bark has  failed.   The tubercles, or
 knots, on the roots of young oaks, are said
 to possess  the same properties as the nut-
 galls, and to be produced in a similar man-
 ner.
   For their acid, see  Acid (Gallic).
   •  Galvanism.  The following article
 is chiefly extracted from  a paper,  which
 was read by me  at the Glasgow Literary
 Society, December 10, 1818, and published
 in the Journal  of Science and the Arts, of
 the  following  January.  I have now sub-
joined a few further observations, on the
 application of voltaic electricity to the re-
 suscitation of  the  suspended functions of
 life.
   Convulsions  accidently  observed in the
 limbs of dead frogs, originally suggested
 to Galvani, the study of certain phenome-
 na, which from him have been styled Gal-
 vanic.   He  ascribed  these  movements to
 an electrical fluid or power, innate in the
 living frame, or capable of being evolved
 by it, which he denominated animal elec-
tricity.  The  Torpedo, Gymnotus, and Silu-
 rus Electricus, fish endowed with a true
 electrical apparatus, ready to be called in-
to action by an effort of their will,  were
previously known  to the naturalist, and
furnished plausible analogies to  the phi-
losopher of Bologna.  Volta, to whom this
 science is indebted for  the  most brilliant
discoveries on its principles, as well as for
its marvellous  apparatus, justly  called by
his name,  advanced  powerful arguments
against the hypothesis of  Galvani.  He as-
cribed the muscular commotions, and other
phenomena, to the  excitation of  common
electricity, by arrangements previously un-
thought of by the scientiflc world; merely
by the mutual contact of dissimilar bodies,
metals,  charcoal, and animal  matter, ap-
plied either  to each  other, or conjoined
with certain fluids.  And  at the present
day, perhaps the only facts which  seem 
GAL                                 GAL
  difficult to  reconcile with  the beautiful
  theory of electro-motion, invented by the
  Pavian professor, are  some  experiments
  of Aldini, the nephew of the original dis-
  coverer-
    In these experiments, neither metals nor
  charcoal were  employed.  Very powerful
  muscular contractions seem  to have been
  excited in  some of the  experiments,  by
  bringing a part of a warm-blooded, and of
  a  cold-blooded  animal, into  contact with
  each other; as the nerve  and muscle of a
  frog, with the bloody flesh of the neck of a
  newly  decapitated  ox.   In  other experi-
  ments, the  nerves and muscles of the same
  animal seem to have operated Galvanic ex-
  citation; and again, the nerve of one animal
  acted with the muscle of another. He de-
 duces  from his  experiments,  an inference
 in favour of his uncle's hypothesis, that a
 proper animal electricity is inherent in the
 body,  which  does not require  the  assis-
 tance of any external agent, for its de velope-
 ment.   Should   we  admit the reality  of
 these results, we may perhaps venture to
 refer them  to a principle analogous to Sir
 H. Davy's pile, or voltaic circuit of two dis-
 similar liquids and charcoal.  This part of
 the subject is however involved in deep
 obscurity.
   Many experiments have been performed,
 in  this  country and abroad, on the bodies
 of criminals,  soon after their execution.
 Vassali, Julio, and  Rossi made an ample
 set, on  several  bodies decapitated at Tu-
 rin.  They  paid  particular attention to the
 effect of galvanic electricity on the heart,
 and other involuntary muscles: a  subject
 of much previous controversy.  Volta as-
 serted, that these muscles are not at all
 sensible to  this  electric power.   Fowler
 maintained, that they were  affected; but
 with difficulty and in a slight degree. This
 opinion was confirmed by Vassali; who fur-
 ther showed,  that the muscles of the sto-
 mach, and intestines, might thus also be
 excited.  Aldini, on the contrary, declared,
 that he  could not affect the heart, by his
 most powerful galvanic arrangements.
   Most  of  the above  experiments  were
 however  made,  either without a voltaic
 battery, or with  piles, feeble  in compari-
 son with those now employed.  Those in-
 deed performed on the body of a criminal,
 at Newgate, in which the limbs were vio-
 lently agitated; the eyes opened and shut;
 the  mouth and jaws worked  about,  and
 the whole face thrown into frightful con-
 vulsions, were made by  Aldini, with  I be-
 lieve, a considerable series of voltaic plates.
  A circumstance of the first  moment, in
 my opinion,  has been too much overlooked
 in experiments of this kind,—that a mus-
cular mass through which the  galvanic en-
ergy is directly transmitted, exhibits very
weak contractile  movements,  in compari-
  son with those which can be excited by
  passing the influence along the principal
  nerve of the muscle.  Inattention to this
  important distinction, I conceive to be the
  principal source of the slender effects hi-
  therto produced in such  experiments on
  the heart, and other muscles, independent
  of the will.  It ought also to be observed,
  that too little distinction  has been made
  between the positive and negative poles of
  the battery; though there are good reasons
  for supposing, that their powers on muscu-
  lar contraction are by no means the same.
   According to  Ritter,  the electricity of
 the  positive  pole augments,  while the
 negative diminishes  the  actions  of  life.
 Tumefaction of parts is produced by the
 former; depression by the latter. The pulse
 of the hand, he says, held a few minutes
 in contact with the positive pole, is strength-
 ened;  that of the one in contact with the
 negative is enfeebled; the former is accom-
 panied with a sense  of heat, the latter with
 a feeling of coldness.  Objects appear to a
 positively electrified eye, larger, brighter,
 and red; while to one negatively electrifi-
 ed, they seem smaller,  less distinct,  and
 bluish,—colours  indicating opposite  ex-
 tremities ofthe prismatic spectrum.  The
 acid and alkaline tastes, when the tongue
 is acted on in succession by the two elec-
 tricities, are  well known, and have been
 ingeniously accounted for  by Sir H. Davy,
 in his admirable Bakerian  Lectures.  The
 smell of oxymuriatic acid, and of ammonia,
 are said by Ritter, to be the opposite odours,
 excited by the two opposite poles; as a full
 body of  sound and  a  sharp  tone  are  the
 corresponding effects on the ears.  These
 experiments require verification.
   Consonant in some respects, though  not
 in all, with these statements, are the doc-
 trines taught by a London practitioner, ex-
 perienced in the administration of medical
 electricity.   He affirms, that the influence
 of the electrical fluid of our common ma-
 chines, in the cure  of disease, may be re-
 ferred to three  distinct heads;  first,  the
 form of radii, when projected from a point
 positively electrified; secondly,  that of a
 star, or the negative fire, concentred on a
 brass ball; thirdly, the Leyden explosion.
 To each of these forms he assigns a speci-
 fic action. The first acts as a sedative, al-
 laying  morbid activity; the  second as a
 stimulant; and the last has a deobstruent
operation, in dispersing chronic tumours.
 An ample narrative  of cases is  given in
confirmation of these general propositions.
 My own  experience  leads me to suppose,
that the negative pole of a  voltaic battery,
gives  more  poignant sensations than the
positive.
  But, unquestionably, the most precise
and interesting researches on the relation
between voltaic electricity and the pheno- 
GAL
CAL
mena of life,  are those  contained in Dr.
Wilson Philip's Dissertations in the Philo-
sophical Transactions, as well as in his Ex-
perimental Inquiry into  the Laws of the
Vital Functions, more recently published.
  In his earlier researches, he endeavoured
to prove, that the circulation of the blood,
and the action of the involuntary muscles,
were independent of the nervous influence.
In a late paper, read in January 1816, he
showed the immediate dependence of the
secretory functions on the nervous  influ-
ence.
  The eighth pair of nerves distributed to
the stomach, and subservient to digestion,
were divided by incisions in the necks of
several living rabbits.  After the operation,
the parsley which they ate remained with-
out  alteration in their stomachs; and the
animals, after evincing much  difficulty of
breathing, seemed to die of suffocation.
But when in other rabbits, similarly  treat-
ed,  the  galvanic  power was  transmitted
along the nerve,  below  its section, to  a
disc of  silver, placed closely in  contact
with the skin of the animal, opposite to its
stomach, no difficulty of breathing occur-
red.  The voltaic  action  being kept up for
twenty-six hours, the rabbits were then
killed, and  the  parsley  was  found  in as
perfectly digested a state, as that in healthy
rabbits fed at the same time; and their sto-
machs evolved the smell peculiar to that
of  a rabbit during digestion.  These ex-
periments were  several times  repeated
with similar results.
   Hence it appears that the galvanic energy
is capable of supplying  the  place of  the
nervous influence, so that while under it,
the stomach, otherwise  inactive, digests
 food as usual. 1 am not, however, willing
to adopt the conclusion drawn by its inge-
nious author, that the " identity of galvanic
electricity and nervous  influence  is esta-
blished by these experiments." They clear-
 ly show a remarkable analogy between these
 two powers, since the one may serve as a
 substitute for the other.  It might possibly
 be urged by the anatomist, that, as the sto-
 mach is supplied  by twigs of  other nerves,
 which communicate under the place of Dr.
 Philips' section of the par vagum, the gal-
 vanic fluid may operate  merely as a pow-
 erful stimulus, exciting those slender twigs
 to perform such  an increase  of action,  as
 may compensate for the want of the prin-
 cipal nerve.   The above experiments were
 repeated on  dogs,  with like results; the
 battery  never being so strong as to occa-
 sion painful shocks.
   The removal of dyspnoea as  stated  above,
 led him to  try galvanism as  a remedy  in
 asthma.  By transmitting its influence from
 the nape of the neck to  the pit of the sto-
 mach, he gave decided relief in every one
 of twenty-two eases,  of which fslu* were
in private practice,  and eighteen in the
Worcester Infirmary.  The power employ-
ed varied from ten to twenty-five pairs.
  The general inferences deduced by him
from his multiplied experiments, are, that
voltaic  electricity is capable  of effecting
the formation of the secreted fluids when
applied to the blood, in the same way in
which the nervous influence is applied to
it; and that it is  capable of occasioning  an
evolution of caloric from  arterial blood.
When the lungs are deprived of the ner-
vous influence, by which their function is
impeded, and even destroyed, when di-
gestion is interrupted, by withdrawing this
influence from the stomach, these two vital
functions are renewed  by  exposing them
to  the  influence  of a galvanic  trongh.
" Hence," says he, " galvanism seems ca-
pable  of performing all the  functions of
the nervous influence  in  the animal eco-
nomy; but obviously it cannot excite the
functions of animal life, unless when acting
on parts endowed with the living principle."
   These results of Dr. Philip have been re-
cently  confirmed  by Dr.  Clarke Abel, of
Brighton, who employed, in one ofthe repe-
titions of the experiments, a comparatively
weak, and in the other a considerable pow-
er of  galvanism.  In the former, although
the galvanism was not of sufficient power
 to occasion  evident digestion of the food,
yet the efforts to vomit, and the difficulty
of breathing, constant  effects of dividing
the eighth pair  of nerves, were prevented
by it.  These symptoms recurred when it
 was discontinued, and  vanished on its re-
 application.   " The respiration of the ani-
 mal," he observes, " continued quite free
 during  the  experiment, exctpt  when  the
 disengagement  of the nerves from the tin-
 foil,  rendered a  short suspension of  the
 galvanism necessary during their readjust-
 ment."  "The non-gdvanizedrabbit,breath-
 ed with difficulty,  wheezed audibly, and
 made frequent attempts to vomit."  In the
 latter  experiment,  in  which  the  greater
 power  of  galvanism  was employed,  di-
 gestion went on as  in  Dr.  Philips' experi-
 ments.—Jour. Sc. ix.
   M. Gallois, an eminent French physiolo-
 gist, had endeavoured to prove, that  the
 motion of the heart depends entirely upon
 the spinal marrow, and immediately ceases
 when the spinal marrow is removed or de-
 stroyed.  Dr. Philip appears to have re-
 futed this notion, by the following experi-
 ments.   Rabbits were  rendered insensible
 by a blow on the  occiput;  the spinal  mar-
 row and brain were then removed, and the
 respiration kept up by artificial means: the
 motion of the heart, and  the circulation,
 were carried on as usual.   When spirit of
 wine, or opium, was applied to  the spinal
 marrow or brain, the  rate of the circula-
 tion  was accelerated. 
GAL
GAL
  These general physiological views  will
serve,  I hope, as no  inappropriate intro-
duction to the detail of the  galvanic phe-
nomena, exhibited here on the 4th of No-
vember, in the body of the murderer Clydes-
dale; and they may  probably guide us to
some valuable practical inferences.
  The subject of these experiments was a
middle-sized, athletic, and extremely mus-
cular man, about thirty years of age.   He
was suspended from the galloWs nearly an
hour, and made no convulsive struggle after
he dropped;  while a thief, executed along
with him, was violently agitated for a  con-
siderable time.   He was brought to the
anatomical  theatre of our university  in
about ten minutes after he was cut down.
His  face had a perfectly  natural aspect,
being neither livid nor tumefied; and there
was no dislocation of his neck.
   Dr. Jeffray, the distinguished professor
of anatomy,  having on the preceding day
tequested me to perform the galvanic ex-
periments, I sent to his theatre with this
view, next morning, my minor voltaic bat-
tery, consisting of 270 pairs of four  inch
plates, with  wires of  communication, and
pointed metallic rods  with insulating han-
dles, for the more commodious application
of the electric power.  About five minutes
before the police officers arrived with the
body, the battery was charged  with  a  di-
lute nitro-sulphuric acid,  which speedily
brought it into a state, of intense action.
The dissections were skilfully executed
by  Mr.  Marshall, under  the  superinten-
 dence of the professor.
   Exp. 1. A large incision was made into
the nape of the neck,  close below the occi-
put.   The posterior half of the atlas ver-
 tebra  was then  removed by bone forceps,
 when the spinal marrow was brought into
 view.  A profuse flow of liquid blood gush-
 ed  from the wound,  inundating the floor.
 A considerable incision was at the  same
 time  made  in  the left hip,  through the
 great gluteal muscle,  so as to bring the
 sciatic nerve into sight; and a small cut
 was made in  the heel.  From neither  of
 these did any blood flow.  The pointed
 rod connected with one end of the batiery,
 was now placed in contact with the spinal
 marrow, while the other  rod was  applied
 to the sciatic nerve.   Every muscle of the
 body was immediately agitated  with  con-
 vulsive movements,  resembling a violent
 shuddering  from cold.  The left side was
 most powerfully convulsed at each renewal
 ofthe electric contact. On moving the se-
 cond rod from the hip to the heel, the knee
 being previously bent, the leg was thrown
 out with such violence, as  nearly to over-
 turn one of the assistants, who in vain at-
 tempted to  prevent its extension.
    Exp. 2. The left phrenic nerve was now
 laid bare at the outer edge of the sferno-
thyroideus muscle, from three to four inches
above the clavicle; the cutaneous incision
having been made by the side of the ster-
no-cleido-mastoideus.  Since this nerve is
distributed to the diaphragm, and since it
communicates  to the heart through the
eighth pair, it was expected, by transmit-
ting the galvanic power  along it,  thR the
respiratory process would be renewed. Ac-
cordingly,  a small incision having  been
made under the cartilage of the seventh
rib, the point of the one insulating rod was
brought into contact with the great head
of  the diaphragm, while the other  point
was applied to  the phrenic nerve  in the
neck.  This muscle, the main agent of res-
piration, was instantly contracted, but with
less force than  was  expected.  Satisfied,
from ample experience  on the living body,
that more powerful effects can be produced
in galvanic excitation, by leaving the  ex-
treme communicating rods in close contact
with the parts to be operated on, while the
electric chain or circuit is completed, by
running the end of the  wires along the top
of the plates in  the last trough  of either
pole,  the  other wire  being steadily  im-
mersed in the last cell of the opposite pole,
 I had immediate recourse to this method.
 The success  of it  was truly  wonderful.
 Full,  nay,  laborious breathing, instantly
 commenced.  The chest heaved, and fell;
 the  belly was  protruded, and  again  col-
 lapsed, with the relaxing and retiring dia-
 phragm. This process was continued, with-
 out interruption, as long as I continued the
 electric discharges.
    In the judgment of many scientific gen-
 tlemen who witnessed  the scene, this  res-
 piratory experiment  was perhaps the most
 striking ever made  with  a philosophical
 apparatus.  Let it also be remembered, that
 for full half an  hour  before this period, the
 body had  been well nigh drained of its
 blood, and the  spinal marrow severely la-
 cerated.  No pulsation could be perceived
 meanwhile at the heart or wrist; but it may
 be supposed, that but for  the  evacuation
 of the  blood,—the  essential stimulus  of
 that organ,—this phenomenon might  also
 have occurred.
    Exp. 3. The supra-orbital nerve was laid
 bare in the forehead, as it issues through
 the supra-ciliary foramen,  in the eyebrow:
 the one conducting  rod being  applied  to
 it, and the other to the heel, most extraor-
 dinary grimaces were exhibited every time
 that the electric discharges were made, by
 running the  wire in my  hand  along the
 edges of the last trough,  from  the 220th
  to the 270th pair of plates; thus fifty shocks,
  each greater than the preceding- one, were
  given in two seconds: every muscle in his
  countenance  was simultaneously thrown
  into fearful action; rage,  horror,  despair,
  anguish, and ghastly smiles, united their 
GAL                                  GAL
 hideous expression in the murderer's face,
 surpassing far the wildest representations
 of a Fuseli or a Kean.  At this period se-
 veral of the spectators were forced to leave
 the apartment from terror or sickness, and
 one gentleman fainted.
   Exp. 4. The last  galvanic experiment
 consisted in transmitting the electric power
 from the  spinal marrow to the ulnar nerve,
 as it passes by the  internal condyle at the
 elbow; the fingers now moved nimbly, like
 those of a violin performer; an assistant,
 who tried to close the fist, found the hand
 to open forcibly, in  spite of  his efforts.
 When the one rod was applied to  a  slight
 incision in the tip of the fore-finger, the
 fist being previously clenched,  that finger
 extended instantly; and from the convul-
 sive agitation of the arm, he  seemed  to
 point to the different spectators, some  of
 whom thought he had come to life.
   About an hour was spent in  these ope-
 rations.
   In deliberating on the above galvanic
 phenomena, we are almost willing to ima-
 gine, that  if, without cutting into and
 wounding the spinal  marrow and blood-
 vessels in the neck, the pulmonary organs
 had been  set a-playing at  first, (as 1 pro-
 posed), by electrifying the phrenic nerve,
 (which may  be  done without any dange-
 rous incision), there is a probability that
 life might have been restored.  This event,
 however little desirable with a murderer,
 and perhaps contrary to  law,  would yet
 have been pardonable in one instance, as
 it would have been highly honourable and
 useful to  science.  From  the accurate ex-
 periments of Dr.  Philip,  it appears, that
 the action of the diaphragm and lungs  is
 indispensable towards restoring the sus-
 pended action of the heart and great ves-
 sels, subservient to the circulation of the
 blood.
   It is known, that cases of death-like le-
 thargy, or suspended animation, from dis-
 ease and accidents, have occurred, where
 life has returned, after longer interruption
 of its functions, than in the subject of the
 preceding  experiments.   It  is  probable,
 when apparent death supervenes from suf-
 focation with noxious gases, &c. and when
 there is no organic laesion, that a judicious-
 ly directed galvanic experiment will, if any
 thing will, restore the activity of the vital
 functions.  The plans of administering vol-
taic electricity  hitherto  pursued in such
 cases, are,in my humble apprehension, very
 defective.  No advantage, we perceive,  is
 likely to accrue from passing electric dis-
 charges across the chest, directly through
the heart and lungs.  On the principles so
well developed by Dr. Philip, and now il-
lustrated on Clydesdale's body, we should
transmit along the channel of the nerves,
 that substitute for nervous  influence,  or
 that power which may  perchance awaken
 its dormant faculties.  Then, indeed, fair
 hopes may be formed of deriving extensive
 benefit from galvanism;  and of raising this
 wonderful agent  to  its  expected  rank,
 among the ministers of  health and life  to
 man.
   I would, however, beg leave to suggest
 another nervous channel, which I conceive
 to be a still readier and more powerful one,
 to the action of the heart and lungs, than
 the phrenic nerve.  If a longitudinal inci-
 sion be made, as is  frequently done for
 aneurism, through the integuments of the
 neck at the outer  edge  of the sterno-maa-
 toideus muscle, about half-way between the
 clavicle and angle of the lower jaw; then on
 turning over the edge of this muscle, we
 bring into view the throbbing carotid, on
 the outside of which, the par vagum, and
 great sympathetic nerve, lie together  in
 one  sheath.  Here,  therefore,  they may
 both be directly touched and pressed by a
 blunt metallic  conductor.  These  nerves
 communicate directly, or indirectly, with
 the  phrenic; and  the superficial nerve  of
 the heart is sent off from the sympathetic.
   Should,  however, the phrenic nerve be
 taken, that of the left side is the prefera-
 ble of the two.  From the position of the
 heart, the left  phrenic  differs a little  in
 its course from the right.  It passes over
 the pericardium, covering the apex of the
 heart.
   While the point of one metallic conduc-
 tor is applied to the nervous cords  above
 described, the other knob ought to be firm-
 ly pressed against the side of the person,
 immediately under the cartilage  of the se-
 venth rib.  The skin should be moistened
 with a solution of  common salt,  or what is
 better,  a hot  saturated  solution  of  sal
 ammoniac, by which means, the electric
 energy will be  more effectually conveyed
 through the cuticle,  so  as to complete the
 voltaic chain.
   To lay bare the  nerves above described,
 requires, as I have stated, no formidable
 incision, nor does it demand more anato-
 mical skill, or surgical dexterity, than every
practitioner of the  healing art ought to pos-
 sess.  We should always bear in mind, that
the subject of experiment is at least  insen-
 sible to  pain; and that life is  at stake, per-
 haps irrecoverably gone.  And assuredly, if
we place the risk and difficulty of the ope-
rations,  in competition with the  blessings,
 and glory consequent on success, they will
 weigh as nothing,  with the intelligent and
 humane.  It is possible,  indeed,  that two
 small brass knobs, covered with cloth mois-
tened with solution of sal ammoniac, pres-
 sed above and below,  on the place of the
nerve,  and the diaphragmatic region, may 
GAL
GAL
suffice, without any surgical operation: It
may first be tried.
  Immersion of the body in cold water ac-
celerates greatly the extinction of life aris-
ing from suffocation; and hence less hopes
need be entertained, of recovering drown-
ed persons after a considerable interval,
than when the vital heat has been suffered
to continue with little abatement.  None of
the ordinary practices judiciously enjoined
by  the Humane  Society, should ever  on
such  occasions be  neglected.  For it is
surely culpable to spare  any pains which
may contribute, in the slightest degree, to
vecal the fleeting breath of man to its che-
rished mansion.
  My attention has been again particularly
directed to this interesting subject, by a very
flattering letter which I lately received, from
the learned secretary of the Royal Humane
Society.
  In the preceding account, I had acciden-
tally omitted to state a very essential cir-
cumstance relative to the electrization of
Clydesdale.  The paper indeed was very
rapidly written, at the busiest period of my
public prelections, to be  presented to the
society, as a substitute for the essay of an
absent friend, and was sent off to London,
the morning after it was read.
  The positive pole or wire connected with
the zinc end ofthe battery, was that which
I applied to the nerve; and the negative, or
that connected with  the  copper end, was
that which I  applied to the muscles.   This
is a matter of primary importance, as the
following experiments will prove.
  Prepare the posterior limbs of a frog, for
voltaic electrization,  leaving the  crural
nerves connected, as usual, to a detached
portion of the spine.   When the excitabi-
lity  has become nearly exhausted, plunge
the limbs into the water of one wine glass,
and the crural nerves with  their pendent
portion of spine, into that of the other. The
edges of the two glasses, should be almost
in contact.   Then taking a rod of zinc in
one hand, and a rod of silver (or a  silver
tea-spoon) in the other, plunge the former
into the water  of the hmbs' glass, and the
latter into that of the nerves' glass, without
touching the frog itself, and gently  strike
the dry parts of the bright metals together.
Feeble convulsive movements,  or  mere
twitching of the fibres, will  be  perceived
at every contact.  Reverse now the  posi-
tion of the metallic rods; that is, plunge
the zinc into the nerves' glass, and the sil-
ver into the other.  On renewing the con-
tact of the dry surfaces of the metal now,
very lively convulsions will take place; and
if the limbs are skilfully disposed in a nar-
rowish conical glass,  they  will probably
spring out to some distance.  This inter-
esting experiment may be agreeably varied
in the following way, with an assistant ope*
rator: Let that person seize in the moist
fingers of his left hand, the spine and ner-
vous cords  of the prepared frog; and in
those of the right hand, a silver rod; and
let the other person lay hold of one of the
limbs with his right hand, while he holds
a zinc rod in the moist fingers of the left.
On making the metallic contact, feeble con-
vulsive twitchings will be perceived, as be-
fore.  Holding still the frog as above, let
them merely exchange the pieces of metal.
On renewing the contacts now, lively move-
ments will take place, which become very
conspicuous, if one limb be held nearly ho-
rizontal, while the other hangs freely down.
At  each touch  of  the voltaic pair,  the
drooping limb will start up, and strike the
hand of the experimenter.
  It is evident, therefore, that for the pur-
poses of resuscitating dormant irritability
of nerves, or contractility of their subordi-
nate muscles, the positive pole must be ap-
plied to the former, and the negative to the
latter.   I  need  scarcely suggest, that to
make the above  experiments analogous to
the condition of a  warm-blooded  animal,
apparently dead, the frog must have its
excessive voltaic sensibility  considerably
blunted, and brought near the standard of
the latter, before  beginning  the  experi-
ments.  Otherwise,  that  animal  electro-
scope, incomparably more delicate than the
gold leaf condenser, will give very decided
convulsions with either pole.
  At the  conclusion of the article Caloric,
I have taken the liberty of suggesting some
simple  and  ready  methods of supplying
warmth to the body of a drowned person."
  ■J-  Galvanic Deflagrator.  I have
given this name to  a galvanic apparatus,
which I contrived last autumn, (1820), and
of which  a plate is annexed at the end  of
this work.   It differs from other galvanic
batteries, 1st, In consisting of concentric
coils, instead of flat  plates; and in being so
constructed, as to permit of a simultaneous
immersion ofthe whole series at the same
instant. 2dly, Under one of its forms,  in
not having  the  pairs of plates insulated,
but placed in two troughs, each containing
forty.   In consequence of the simultaneous
action,  the effects of this  deflagrator far
exceeded those  of voltaic piles or troughs,
of  equal  number and extent of surface.
The light, given out by the combustion of
iron wire and charcoal, was so intense as to
affect the eyes  of spectators  painfully  at
fifty feet distance.
  In  its uninsulated  form,  it produced,
with fresh water, a sensation in the back of
the hand, almost intolerable.   For further
particulars, I refer to Silliman's Journal for
February, 1821.f
  Gamboge is a concrete vegetable juice, 
GAR
GAS
the produce of two trees, both called by the
Indians caracapulli (gambogia gutta Lin.),
and is partly of a  gummy and partly  of a
resinous nature.  It is brought to us either
in form of orbicular masses, or of cylindri-
cal rolls of various si/.es; and is of a dense,
compact and firm texture, and of a beauti-
ful yellow.  It is chiefly -brought to us from
Cambaja, in the East Indies, called  also
Cambodja,  end  Cambogia; and hence it has
obtained  its name of cambadium,  cambo-
gium, gambogium.
  It is a very rough  and strong purge; it
operates both by vomit and stool, and  both
ways  with much violence, almost in the in-
stant  in which it is swallowed, but yet, as
it is said, without griping.  The  dose is
from two to four grains as a cathartic; from
four to eight grains prove emetic and pur-
gative.  The roughness of its operation is
diminished  by  giving it in a liquid form
sufficiently diluted.
  This gum-resin is soluble both in water
and in alcohol.  Alkaline solutions possess
a deep red colour,  and pass the filter.  Dr.
Lewis informs us,  that it gives a beautiful
and durable citron-yellow stain to marble,
whether  rubbed in substance on  the hot
stone, or applied, as dragon's blood some-
times is, in form  of a spirituous tincture.
When it is applied on cold marble, the stone
is afterward to be heated to make the co-
lour penetrate.
  It is chiefly used as a pigment in water
colours, but does not stand.
  Gangue.  The stones which fill the ca-
vities that  form the  veins  of metals are
called the gangue, or matrix of the ore.
  * Garnet.   Professor Jameson divides
this mineral genus into 3 species; the pyra-
midal garnet, dodecahedral garnet, and pris-
matic garnet.
  I.—Pyramidal contains 3 sub-species, Ve-
suvian, Egeran, and Gehlenite, which see.
  II.—Dodecahedral garnet contains 9 sub-
species.  1. Pyreneite.  2. Grossulare.  3.
Melanite.   4. Pyrope.  5.  Garnet.  6. Al-
locliroite.   7. Colophonite.  8. Cinnamon-
stone. 9. Helvin.
  III.—Prismatic garnet; the grenatite.
  We shall treat  here only of the garnet,
proper.  Of this sub-species, we have two
kinds, the precious and common.
  Precious or noble garnet.  Colours dark
red,  falling into blue.  Seldom massive,
sometimes  disseminated,  most  commonly
in roundish grains, and crystallized. 1.  In
the rhomboidal dodecahedron, which is the
primitive form; 2. Do. truncated on all the
edges; 3. Acute double eight-sided pyra-
mid;  and 4. Rectangular four-sided prism.
The  surface of  the  grains  is generally
rough, uneven, or  granulated; that  of the
crystals is  always  smooth.  Lustre exter-
nally glistening; internally shining, border-
ing  on  splendent.  Fracture conchoidal.
Sometimes it  occurs  in  lamellar distinct
concretions.  Transparent  or translucent.
Refracts single.   Scratches quartz, but not
topaz.   Brittle.  Rather  difficultly frangi-
ble.  Sp. gr. 4.0 to 4.2.  Its  constituents
are, silica 39.66, alumina  l9.6<\ black oxide
of iron 39.68,  oxide of manganese 1.80.—
Berzelius.  Before the blow-pipe, it fuses
into  a black enamel, or scoria.  It occurs
imbedded in primitive rocks, and primitive
metalliferous beds.  It is found in various
northern counties in Scotland; in Norway,
Lapland, Sweden, Saxony,  France, &c.  It
is cut for ring-stones.  Coarse garnets are
used as emery for polishing metals.   The
following vitreous composition imitates the
garnet very closely:
     Purest white glass, 2 ounces
     Glass  of antimony,  1 ounce
     Powder of Cassius,  1 grain
     Manganese,         1  grain—Jamesm.
  The garnets of Pegu are most highly va-
lued.
  Common garnet.—Brown  and green  are
its most common  colours.    Massive,  but
never in grains or angular pieces.  Some-
times crystallized;  and  possesses all  the
forms  of the precious  garnet.   Lustre,
shining or glistening.   Fracture, fine grain-
ed uneven.  More or  less translucent; the
black  kind nearly opaque.   It  is a little
softer than precious garnet.   Rather diffi-
cultly frangible.  Sp. gr. 3.7.  Before the
blow-pipe it melts more easily  than  pre-
cious garnet. Its constituents are 38 silica,
20.6  alumina, 31.6 lime, 10.5 iron.—Van.
quelin.   It  occurs  massive  or crystallized
in drusy cavities, in beds, in mica-slate, in
clay-slate,  chlorite-slate,  and   primitive
trap.  It is found at Kilranelagh and Done-
gal in  Ireland; at Arendal and Drammen
in Norway, and in  many other  countries.
On account of its easy fusibility and  rich-
ness in iron, it is frequently  employed as
a flux  in smelting rich  iron ores.   It is
sometimes used instead of emery by lapi-
daries.—Jameson*
  * Gas.  This name is given  to all per-
manently elastic  fluids, simple or  com-
pound,  except the atmosphere, to which
the term Air is appropriated.
  The  solid state, is that'in which, by the
predominance of the  attractive forces, the
particles are  condensed into a coherent
aggregate; the  gaseous state,  is that in
which  the repulsive forces have acquired
the  ascendency over  the  attractive;  and
the liquid  condition represents  the equili-
brium  of these two powers.  Vapours are
elastic fluids,  which have  no permanence;
since a moderate reduction of temperature
causes  them to assume the liquid or solid
aggregation.
  Cohesive attraction among homogeneous 
GAS                                  GAS
particles, is the great antagonist to chemi-
cal affinity, the attraction of composition,
the force  which tends to bring into inti-
mate union, heterogeneous particles. Hence
the juxtaposition of two  solids, of a solid
and a  liquid, or even of  two liquids, may
never determine  their chemical combina-
tion, however strong their reciprocal affini-
ty shall be.
   In the case of two liquids, or a liquid
and a  solid, mere juxtaposition requires,
that the denser body be undermost,  and
that no disengagement of gas, or external
vibration, agitate the surfaces  in contact.
Hence those world  frainers, who ascribe
the saltness ofthe sea to supposed beds of
rock  salt at its bottom, have still the phe-
nomenon of the strong impregnation of the
surface to explain; for the profownd tran-
quillity which  is known to reign at very
moderate  depths  in this  mighty mass,
would forever prevent the diffusion of the
saturated brine below, among the light wa-
ters above.  Or if this tranquillity be  dis-
puted, then progressive density from above
downwards should be found, and continu-
ally increasing  impregnation.  Now none
of these  results has occurred.   But with
gases in contact, there is no obstacle from
cohesive attraction, to the exertion of their
reciprocal affinities.  Hence, however fee-
 ble these may be,  they never fail, sooner
 or later, to cause  an intimate mixture of
 different gases, in which the ultimate  par-
 ticles approach within the limit correspond-
 ing to their reciprocal action.  The differ-
 ence of density may delay, but cannot pre-
 vent uniform diffusion.  Thus we see  that
 known powers can  account for the pheno-
 mena. There is no need therefore of hav-
 ing recourse to the strange hypothesis of
 Mr.  Dalton, that one gas is a neutral unre-
 sisting void with regard  to another, into
 which it will rush by its innate  expansive
 force. But of this fancy suiScient notice
 has  been taken in the article Air  (At-
 mospheric)
    The principle of gaseous combination,
 first broached  in the neglected treatise of
 Mr.  Higgins,  but since  developed  with
 consummate sagacity from the original re-
 searches of M.  Gay-Lussac, has thrown a
 new light on pneumatic chemistry, which
 has  been reflected into all  its mysterious
 departments, of animal  and vegetable ana-
 lysis.  Having given the details under the
 article Equivalents  (Chemical),  we  shall
 merely state in  this place, that the combi-
 nations of gaseous bodies,  are always ef-
 fected in simple ratios of the volumes, so
 that if we represent one of the terms by
 unity, or 1, die other is 1, 2, or at most 3.
 Thus ammoniacal gas  neutralizes exactly
 a volume equal to its own, of the  gaseous
 acids.  It is hence probable, that it the al-
    Vol.  II.
kalis and  acids were  in the elastic state,
they would all combine, each in equal vo-
lume with another, to produce neutral
salts.  The capacity of saturation  of the
acids and alkalis, measured  by volumes,
would  then be the same; and perhaps this
would  be  the best manner of estimation.
In the following tables of gaseous combi-
nation, bodies naturally in the solid state,
like sulphur, carbon and iodine, will be re-
ferred to  their gaseous densities, or the
bulks which  they occupy  relative to their
weights, when diffused by chemical com-
bination among the particles of a perma-
nently elastic fluid.  This view of the sub-
ject, first introduced by  M. Gay-Lussac,
and happily  exemplified  in his excellent
memoir on iodine, will simplify our repre-
sentation of many compounds. Finally,  the
apparent contractions or condensations of
volume, which gases suffer by their reci-
procal affinity, have also simple ratios with
the volume of one of them; a property pe-
culiar to gaseous bodies.  We shall distri-
bute under the following  heads, our gene-
ral  observations  on  gases.   1.  Tabular
views  of the densities, and combining ra-
tios of the gases.   2.  A description of their
 general habitudes with solids and liquids.
 3.  An account of the principal modes of
 analyzing gaseous mixtures. 4. Of gasome-
 try, or the measurement of the density and
 volume of gases.
   1. We  are indebted to Dr. Prout for an
 able memoir on  the  relation between  the
 specific gravities of bodies in their gaseous
 state, and the weights of their atoms, or
 prime equivalents, inserted in the sixth vo-
 lume  of  the Annals  of Philosophy.   His
 observations are founded on M. Gay-Lus-
 sac's doctrine of volumes.  Dr. Prout con-
 siders atmospheric air as a chemical com-
 pound, constituted by bulk of. four volumes
 of azote  and one of oxygen; and, reckon-
 ing the atom of oxygen as 10, and that of
 azote as  175, it  will be found to consist of
 one atom of oxygen, and  two  atoms of
 azote, or per cent of oxygen 22.22
                     Azote 77.77
 Though  almost  all experiments  have hi-
 therto led  us to regard the atmosphere as
 containing  21  volumes in the  100 of  oxy-
 gen, we must in this view, ascribe the ex-
 cess of one per  cent to an error of obser-
 vation.   Now, it is not improbable, that in
 the explosive eudiometer  with hydrogen
 over  mercury, or in the  nitrous gas eudi-
 ometer over water,  one per cent of azote
 may be pretty uniformly  condensed.
    Calling the prime equivalent of oxygen,
  1.000, and  that  of azote  1.75, as  deduced
 both  from  nitric  acid and ammonia, we
 may easily calculate the specific gravities of
 these two gaseous elements of the  atmos.
 pheric compound, itself being represented
                       10 
GAS
GAS
in sp. gr.by 1.00, and in the relative weights
of its constituents, by 1.00 -+- 1.75 X 2; or
22.22+77.77.
  The ancient problem of Archimedes, for
determining the fraud ofthe goldsmith, in
making  king  Hiero's  crown, which is so
important in chemistry for computing  the
mean density of a compound, the specific
gravities of whose  two  constituents  are
given; and for thence enabling us, by com-
paring that result, with the density found
by experiment, to discover the change of
volume  due to the chemical action, is of
peculiar value in pneumatic investigations.
It will enable us to solve, without difficul-
ty, the two following problems:—
  1st, Having given  the specific gravity of
a mixed gas, and the specific gravities of
its two constituent gases, to determine the
volume, and consequently the quantity of
each, present  in the mixture.
  2d, Having given  the specific gravity of
a mixed gas, and the proportions by  weight
and  volume of its constituents, to deter-
mine the  specific gravities of each of its
constituents.  In both cases, no  chemical
condensation  or expansion  is  supposed,
and only two  gases are concerned.
  1st, Letdbethesp.gr. of the denser gasi
          I             ofthe lighter gas;
          m            mixed gas;
          x the volume of the denser gas;
          y           of the lighter gas;
          v total volume of the compound.
Then x =

  v (d—m)
v (m—/)
(d— tn) + m—I)
5 and  y
(d—m) + 'm—l)
from one or other of which formulae, the vo-
lume of one or other constituent may be
found;  and by multiplying  the volume by
the specific gravity, its  weight  is given-
The same formula is stated in words under
the article Coal Gas.
  2d, When the specific gravities of the
components are sought; the specific gra-
vity of the compound, as well as the vo-
lume and weight of each component being
given, we have the following formula:—
Let x be the sp. gr. of that whose  weight is
         a and volume m.
    y be the sp. gr. of that whose  weight is
         © and volume n.
      mx+ny
Then "  .„_l„ = *»the SP- Sr-of the com-
        m -f- n
pound whose weight  = 1.

But the volume of one body multiplied into
its specific gravity, is to the volume of ano-
ther, multiplied into its specific gravity, as
the weight of the first, is to that  ofthe se-
cond; or
           mx :ny ::a: b

  And  m -f n—ny = <"%, if s = 1.

  U hence « = •—-—_»
               an-\-bn

  And x =  —'-----2.
                 m
Dr. Prout has very ingeniously applied this
formula, to the determination of the  spe-
cific gravities of oxygen  and  azote, which
are,
           Oxygen,  1.1111
           Azote,   0.9722
His investigation  of the specific gravity of
hydrogen from that of ammonia, is conduct.
ed on principles still less disputable.   The
mean of the experimental results obtained
by MM. Biot and Arago and  Sir  H. Davy
on ammoniacal gas, is 0.5902.  Now it has
been demonstrated, that 2 volumes of it are
resolvable  into 4 volumes of constituent
gases, of  which 3 volumes are hydrogen
and 1 azote.  Hence, if from double the
specific gravity of ammonia,  we  subtract
the specific gravity of azote,  the  remain-
der divided by 3 will be the specific gravi-
ty of hydrogen. Or, putting the same thing
into an algebraic form, on the principle that
the sum of the  weights divided  by the
sum of the volumes, gives the specific gra-
vity of the mixture;  let x be the speci-
fic  gravity of hydrogen, then experiment

shows, that "X+ li'—— = 0.5902; Whence
-2
x    2X0.5902-0.9722 _ntUi^
The
density of hydrogen therefore is to that of
azote, atmospherical air, and oxygen, as 1
to 14, 1 to 14.4, and 1 to 16, respectively.
  And with regard to muriatic acid gas, it
is well known to result from the union of
chlorine and hydrogen in  equal volumes,
without any condensation; therefore if we
call the sp. gr. ofthe compound gas 1.278,
and from the double of that number deduct
the sp. gr. of hydrogen, we shall have the
sp. gr. of chlorine = 1.278 X 2 — 0.0694
= 2.4866,  which may be  converted into
the even number 2.5 without any  chance
of error.  See Sect. IV.
  In the common tables of equivalent ra-
tios, adapted to the hypothesis that water
is a compound of one atom of oxygen and
one of hydrogen, or of half a  volume of
the former and one volume of  the  latter,
we must  compute  the  ratios of gaseous
combination,  among different  bodies, by
multiplying the weight of their atom or
their prime equivalents by half  the sp. gr.
of oxygen = 0.5555.   If the volume and
sp. gr. of hydrogen were reckoned unity,
then the doctrine  of  volumes and prime
equivalents would coincide. 
GAS
GAS
General Table of Gaseous Bodies, by Dr. Ure.
Names.
Hydrogen .....
Carbon ......
Subcarb. hydrogen
Ammonia.....
Steam of water -  -   -
Phosphorus -  -  -   -
Phosphur. hydrogen   -
Subphos. hydrogen -   -
Carbonous oxide   -   -
Carburetted hydrogen -
Azote  -.----
Prussic acid -  -  -   -
Atmospheric air -  -   -
Deutoxide of azote,   -
Oxygen   - -  -  -   -
Sulphur.....
Sulphuretted hydrogen
Muriatic acid   -  -   -
Carbonic add   -  -   -
Protoxide of azote -   -
Alcohol vapour -  -   -
Cyanogen .....
Chloroprussic acid -   -
Muriatic ether  -  -   -
Sulphurous acid -  -   -
Deutoxide of chlorine -
Kluoboric acid  -  -   -
Protoxide of chlorine -
Chlorine  - -  -  -   -
Sulphuric ether vapour
Nitrous acid -  -  -   -
Sulphuret of carbon   -
Sulphuric acid  -  -   -
Chlorocarbonous acid -
Sal ammoniac   -  -   -
Nitric acid  -  -  -   -
Hydriodic acid  -  -   -
Oil of turpentine  -   -
Chloric acid -  -  -   -
Fluoborate of ammonia
Subfluob. ammonia -   -
Tritosubfluob. ammonia
Fluosilicate of ammonia
Sp.gr.
air —
 1.00
10694
J.4166
0.5555
0.5902
0.625
0.833
0.902
0.9722
0.9722
0.9722
0.9722
0.9374
1.0000
1.0416
1.1111
1.1111
1.1805
1.2840
1.5277
1.5277
16133
1.8055
2.1^27
2.219
2.222
2.361
2.371
2.44
2 500
2.586
2.638
2.644
2.777
3.472
3.746
3.75
4.340
5.013
5.277
5.902
7.10
8.26
Weight
 of 100
 cubic
 incites.
  2.118
 12.708
 17-000
 18.000
 19.062
 25.42
 27.47
 29.65
 29.65
 29.65
 29.65
 28.59
 30.519
 31.77
 33.888
 33.888
 36.006
 39.181
 46.596
 46.596
 49.20
 55.07
 65.69
 67.68
 67-77
 72.0
 72.312
 74.42
 76.25
 78.87
 80.48
 80.66
 84.72
105.9
114.3
114.37
132.37
152.9
160.97
180.
216.7
252-
Weight
of prime
 equiv.
oxygen
 =- 1.
0.125
0.750
1.000
2125
1.125
1.500
1.625
1.750
1.750
0.875
1.750
3.375
4.500
3.750
1.000
2.000
2.125
4.6125
2.750
2.750
2.875
3.25
7.75
10.375
4.000
9.50
8.500
5 50
4.50
2.875
4.75
4.750
5.000
6.25
6.75
6.75
15.625

  9.5
10.625
12750
l* 87 o
2 hyd.+l carb
3 hyd.-j-l azot
2 hyd.+l oxy.

lphos+lhyd
lphos+2hyd
2 carb.-j-l oxy
1 carb.+l hyd

1 cyan.+l hyd
1 oxy .-+-4 azot
1 oxy.+laxot
Constituents
    by
  volume.
1 hyd.+l sulp
1 hyd.+l chlo.
1 carb.+l oxy.
I oxy+2 azote
I ol.gas+1 wa
2carb.+lazote
1 cya.-|-l chlo.
1 mur+2 alco
1 oxy.+l sulp.
2 oxy-4-1 chlo.

2 oxy+4 chlo

2 olef.-f-l wat
3oxy+2azote
2 carb.+4 sulp
3 oxy+2 sulp
lchl.-f- lcar.ox
2 am.+2 mm
5 oxy+2 azote
lhyd+liodin

3 oxy+2 chlo.
2am+2fluob
4am.-j-2fluob
6am+2fluob,
2 am +1 acid
?8
a &
Constituent
  prime
equivalents.
2 hyd.+l carb.
3 hyd.+ l azote
1 hyd.+l oxyg.

1 phos.+l hyd.
1 phos+2 hyd.
I carb.+l oxyg.
1 carb.+l hyd.

1 cyan.+l hyd.
1 oxyg +2 azote
2 oxyg.+l azote
I hyd.+l sulph.
1 hyd.+l chlor.
1 carb+2 oxyg.
1 oxyg.+l azote
2ol.gas+l water
2 carb.+l azote
1 cyan.+l chlor.
1 mu. acid+2 ale.
2oxyg.+l sulph.
1 chlor+4 oxyg.

I oxyg.+l chlor.

4 olef.+l water
3 oxyg.+l azote
2 sulph.+l carb.
3 oxyg.+l  sulph
1 chlor.+lcar.ox
1 am.+l mu.acid
5 oxyg.+l azote
1 hyd.+l iodine

5 oxyg.+l chlor
1 am.+l fiuobor.
2 am.+l fluobor.
3 am.+l fluobor.
  In the preceding table I have endeavour-
ed to assemble the  principal features  of
gaseous combination.  For the properties
of these 43 different gases, see the  sepa-
rate articles in the Dictionary.
  II. Of the general habitudes of gaseous
matter with solids and liquids.  Mr. Dal-
ton has written largely on these relations;
but his results are so modified by specula-
tion, that it is difficult to  distinguish fact
from  hypothesis.   Dr. Henry,  however,
made some  good researches on the sub-
ject of this division, but they have  since
been so much extended and improved by
M. de Saussure, that I shall take his  ela-
borate researches for my guide.   His  Me-
moir on the  absorption of the  gases by
different bodies was originally read to the
Geneva  Society on the 16th April  1812, and
appeared in Gilbert's Annalender Physik
for July 1814, from  which it was  trans-
lated into the 6th volume  of the Annals
of Philosophy.
  1. Of the absorption of unmixed  gases
by solid bodies.
  Of all solid bodies charcoal  is  the most 
GAS
GAS
remarkable in its action on the gases.  In  introduced, after it became cool, into the
M. de Saussure's experiments, the red-hot  gas to be absorbed, without ever coming
charcoal was plunged under mercury, and  into contact with atmospherical air.

         Table of the Volumes of  Gases absorbed by one volume of
Gases.	Charcoal.	Meer-schaum.	Adhesive slate.	Lignif. asbestus.	Saxon hydroph.	Quartz.
Ammonia,	90	15	11.3	12.75	64	10
Muriatic acid,	85	—	—	—	17	—
Sulphurous acid,	65	—	—	—	737	_
Sulphuretted hydrogen,	55	11.7	—	—	—	—
Nitrous oxide,	40	3.75	—	_	__	_
Carbonic acid,	35	5.26	2.	1.7	10	0.6
Olefiant gas,	35	370	1.5	1.7	0.8	0.6
Carbonic oxide,	9.42	117	0.55	0.58	_	_
Oxygen,	9.25	1.49	0.7	0.47	0.6	0.45
Azote,	7.5	1.6	0.7	0.47	0.6	0.45
Oxycarburetted hydrogen") from moist charcoal, j	5.0	0.85	0.55	0.41	—	—
Hydrogen,	1.75	0.44	0.48	0.31	0.4	0.37
  The absorption was not increased by al-
lowing the charcoal to remain in contact
with the gases after 24 hours; with the ex-
ception of oxygen, which goes on condens-
ing for years, in consequence of the slow
formation and absorption of carbonic acid.
If the charcoal  be  moistened,  the absorp-
tion of all those gases that have not a very
strong affinity for  water, is distinctly  di-
minished.  Thus boxwood charcoal, cool-
ed under mercury, and drenched in water
while under the mercury, is capable of ab-
sorbing only 15 volumes  of carbonic acid
gas; although,  before being moistened, it
could absorb35 volumes ofthe same gas. Dry
charcoal, saturated with any gas, gives out,
on immersion in water, a quantity  corres-
ponding to the diminution of its absorbing
power.   During the absorption of  gas by
charcoal, an elevation of temperature takes
place,  proportional to  the rapidity  and
amount of the  absorption.  The  vacuum
of the air-pump seems lo possess the same
influence as  heat, in rendering charcoal
capable  of absorbing gaseous matter.   A
transferrer with a  small  jar  containing a
piece of charcoal was exhausted, and be-
ing then plunged into a pneumatic trough,
was filled with mercury. The charcoal was
next introduced into a  gas, and absorbed
as much of it, as after having been ignited.
As the rapid absorption  of carbonic acid
gas by charcoal can raise the thermometer
25°, so its extraction by the air-pump, sinks
it 7.5°.
  Though charcoal possesses the highest
absorbent power, yet it is common  to all
bodies which possess a certain degree of
porosity, after they have been exposed to
the action of the air-pump.  Meerschaum,
like charcoal, absorbs  a  greater bulk  of
rare than dense gas.   Dried woods, linen
threads, and  silks, also absorb the gases.
Of ammonia,  hazel absorbs 100  volumes,
mulberry 88,  linen thread 68, silk 78;  of
carbonic acid, in the above order, 1.1, 0.46,
0.62, 1.1; of this gas,  fir absorbed 1.1, and
wool 1.7.
   The rate of absorption of different gas.
es, appears to be the  same, in all  bodies
of  similar chemical  properties.  All the
varieties of asbestus condense more carbo-
nic acid gas, than oxygen gas; but  woods
condense more hydrogen than azote.  Yet
the condensations  themselves in different
kinds  of asbestus, or wood, or  charcoal,
are very far from being equal.   Lignifbrm
asbestus absorbs a greater volume of car-
bonic acid gas, than rock-cork; so does hy-
drophane than the swimming quartz of St.
Ouen,  and the quartz of Vauvert; and the
absorption of  gases by boxwood  charcoal,
is much greater than by fir charcoal. These
differences are not in the least altered,  if,
instead of equal volumes, equal weights  of
charcoal be employed.  It is curious that
a piece of solid charcoal absorbs 7$ vo-
lumes,  and the same reduced  into fine
powder absorbs only three volumes.  The
absorbing power of most kinds of charcoal
increases as the specific gravity increases;
and it is obvious, that the pores  must be-
come smaller and narrower with the in-
crease of density.  Charcoal from  cork,
of a specific gravity not exceeding 0.1, ab-
sorbed no sensible quantity of atmospheric
air.  Charcoal from fir, sp. gr. 0.4, absorb-
ed 4i times its volume of atmospherical air;
that from boxwood,  sp. gr. 0.6. absorbed
74  of air; and pit-coal of vegetable origin
from Russiberg, sp.  gr. 1.326, absorbed
10} times its volume of air.   But, as the 
GAS                                  GAS
 density  augments, we arrive  at  a limit,
 when the pores become too small to allow
 gases  to enter.  Thus,  the black-lead of
 Cumberland, containing 0.96 of carbon, sp.
 gr. 2.17, produces no alteration on atmos-
 pherical air.   But this correspondence be-
 tween the power of absorbing, and the spe-
 cific gravity, is only accidental.  Accurate
 experiments  show remarkable deviations
 from this  rule.  The different kinds of
 charcoal, whether of  similar or dissimilar
 sp. gravities, always differ from each other
 in their organization. They cannot be con-
 sidered  as resembling  a sponge, whose
 pores and density may be modified  by  pres-
 sure.
   On the whole, it appears that  the pro-
 perty of condensing  gases, possessed by
 some solids, is within certain limits, in the
 inverse ratio  of the  internal diameter of
 the pores  of the  absorbing bodies.   But
 besides the porosity,  there  are two other
 circumstances which  must be attended to
 in these absorptions:  1. The different affi-
 nities which exist  between the gases and
 the solid bodies; and, 2. The power of ex-
 pansion of the gases,  or the  opposition
 they make to their condensation, at diffe-
 rent degrees of  heat  and atmospherical
 pressure.
   The experiments hitherto described re-
 late to the absorption of a single  gas, not
 mixed with any other.  But, when a piece
 of charcoal saturated with either  oxygen,
 hydrogen, azote,  or carbonic acid, is put
 into another gas, it allows a portion of the
 first to escape, in order to absorb  into its
 pores a portion of the  second  gas.  The
 volume of gas thus expelled  from char-
 coal by another gas, varies according to
the proportion in  which both gases  exist
in the  unabsorbed  residue.   The quan-
tity  expelled is greater, the greater the
 excess of the expelling gas.  Yet it is not
 possible,  in  close vessels, to expel the
 whole  of  one gas,  out  of  charcoal, by
 means of another; a small quantity always
 remains in the charcoal.
  Two gases, united by absorption in char-
coal, often experience a greater condensa-
tion than each would in a  separate  state.
For example, the presence  of oxygen gas
in charcoal facilitates the condensation of
hydrogen gas;  the presence of  carbonic
acid gas, or of azote, facilitates  the con-
densation of oxygen gas; and that of hy-
drogen, the condensation  of azote.  Yet,
this effect does not take place, in all cases,
with the four gases now mentioned; for the
presence of azote in charcoal does not pro-
mote the absorption of carbonic acid gas.
When  the absorption of one of the four
named gases, has been facilitated by ano-
ther of them, no perceptible combination
between the two takes place, at least within
the interval  of some days. So, for example,
notwithstanding the  assertion of Rouppe
and Van Noorden, no separation of water
appears, when charcoal saturated  with hy-
drogen at the common temperatures is put
into oxygen  gas; or when the experiment
is reversed.   Nor has azote and hydrogen
been united  in this way into ammonia, or
azote and oxygen into nitric acid.
  2. Absorption of gases by liquids.
  "That all gases are absorbed by liquids,"
says M. de  Saussure, "and that  most of
them are again  separated by heat, or the
diminution of external pressure, has  been
long known.  We now possess accurate re-
sults respecting the rate of this absorption.
For a  set of careful and regular experi-
ments on this subject, we are indebted to
Dr. Henry of Manchester.   Mr. Dalton has
a little altered some of these results; and,
by means of them, has contrived a theory
which  not only explains the absorption of
gases by water, but by all other liquids;
but it is in opposition to most of the re-
sults which  I have obtained by means of
solid porous bodies."
  The following table exhibits the volumes
of the different gases, absorbed, according
to the  accurate experiments of Saussure,
by 100 volumes of
		Alcohol	Naphtha	j Oil of la-	[■	Satur.
Gases.	Water.	sp. gr.	sp. gr.	vender sp	Olive oil	solution
		0.84.	0784.	gr. 0.88.	*	uur.pot.
Sulphurous acid,	4378	11577				
Sulphuretted hydrogen,	253	606				
Carbonic acid,	106	186	169	191	151	61
Nitrous oxide,	76	15.1	254	275	150	21
Olefiant gas,	15.3	127	261	209	122	10
Oxygen gas,	6.5	16.25	—	—	—	—
Carbonous oxide,	6.2	14.50	20	15.6	14.2.	5.2
Oxycarburetted hydrogen,	5.1	7.0				
Hydrogen,	4.6	5.1				
Azote,	4.1	4.2				
 
GAS
GAS
   The above liquids were previously freed
 from air, as completely as possible, by long
 and violent  boiling.    But those  which
 would have been altered or  dissipated by
 the application of such a heat, as oils, and
 some saline solutions, were freed from air
 by means of the air-pump.   To produce a
 speedy and complete absorption, a large
 quantity of those gases which are absorb-
 ed only  in small quantities  by liquids, as
 azote, oxygen,  and hydrogen,  was  put,
 with a small quantity of the liquid,  into a
 flask, which was furnished with  an  excel-
 lent ground stopper.  The  flask  was  agi-
 tated for a quarter of an hour.   This  me-
 thod is difficult and requires much atten-
 tion.   With  respect to all  the gases of
 which the liquid absorbs more than l-7th
 of its bulk, M. de Saussure  proceeded in
the following manner:—He  placed them
 over mercury, in a tube fully lit inches in-
ternal diameter, and let up  a column of
the absorbing liquid, from about 1$ to 2^
inches long.  The absorption was promo-
ted by agitation, and its quantity was not
determined till the gas and the liquid  had
been in contact for several days.
  A hundred volumes  of   water absorb
about five  volumes of atmospherical  air,
when the mass of air is very  great, in com-
parison of that of the water.
  " From these experiments," says M. de
Saussure, "it appears, contrary to Dalton's
assertion, that the absorption of gases, by
different liquids,  not glutinous,  as water
and alcohol, is very far from being similar.
The alcohol, as we see, often absorbs twice
as much of them, as the water does.  In
gases which are absorbed in small quanti-
ties, this difference  is not so striking, be-
cause, with respeet to them, the absorp-
tions of the alcohol can be less accurately
determined, on account of the air  which
still remains in it, after being boiled.
  "These  experiments  agree  no  better
with the law, which Dalton  thinks he has
ascertained in the absorption of  different
gases by one and the  same liquid; for I
find  too great a difference between the
quantity of carbonic  acid, sulphuretted
hydrogen, and nitrous oxide gases, absor-
bed by  the  same liquids (which Dalton
considers as completely equal),  to be
able  to  ascribe it to errors in  the experi-
ments."
  3.  Of the influence of chemical affinity
on the absorption of the gases.
  If such an influence  did  not  exist, the
gases would be absorbed by all liquids in
the same order.   Table of the volumes of
gases absorbed by 100 volumes of
Names of gases.	Naph. sp. gr. 0.784.	Oil of lav. sp. gr. 0.88.	Olive oil.	Solution mur. pot. 10 21 61 5.2
Olefiant gas, Nitrous oxide, Carbonic acid, Oarbonous oxide,	261 254 169 20	209 275 191 15.6	122 150 151 14.2	
  "It follows," says M. de Saussure," from
these experiments, that in liquids, as well
as in solid bodies, great  differences take
place, in the order in which gases are ab-
sorbed by them; and that, in consequence,
these absorptions are always owing to the
influence of chemical affinity.  Solid bo-
dies appear, under the same circumstances,
to produce  a greater condensation of all
gases, in contact with  which  they are
placed, than liquid bodies do.  I have met
with no liquid which  absorbs  so  great a
volume of carbonic acid,  olefiant gas, azo-
tic gas, carbonous oxide,  and  nitrous ox-
ide, as charcoal and meerschaum do. The
difference is  probably owing  to  this cir-
cumstance, that liquids, in consequence of
the great mobility of their parts, cannot
compress the gases so strongly as is ne-
cessary for greater condensation, certain
cases excepted, when very powerful  che-
mical  affinities  come to their assistance;
as, for example, the affinity  of ammonia
and muriatic acid for water.  Only in these
rare cases do liquids condense a greater
quantity of gases than solid  bodies.  Ac-
cording to Thomson, water  in the mean
temperature  of  the atmosphere absorbs
516 times its bulk of muriatic  acid  gas,
and 780 times its bulk of ammoniacal gas."
In the articles muriatic  acid  and  ammonia
in this Dictionary, I have shown these de-
terminations  of Dr. Thomson to  be erro-
neous.
  4. Influence of the viscidity, and the spe-
cific gravity of liquids on their absorption
of gases. Carbonic acid gas was placed in
contact with  one volume of  the  different
liquids.  The temperature in all the expe-
riments was 62.5°. 
GAS
GAS
Liquids.	Sp.gr.	Volume of ear.acid gas absorbed.	100 parts ofthe solution, contain
Alcohol,	0.803	2.6	
Sulph. ether,	0.727	2.17	
Oil of lavender,	0.880	1.91	
Oil of thyme,	0.890	1.88	
Spirit of wine,	0.840	1.87	
Rectified naphtha,	0.784	1.69	
Oil of turpentine,	0.860	1.66	
Linseed oil,	0.940	1.56	
Olive oil,	0.915	1.51	
Water,	1.000	1.06	
Sal ammoniac,	1.078	0.75	2753 crystals, sat. sol.
Gum arabic,	1.092	0.75	25. gum,
Sugar,	1.104	0.72	25. sugar,
Alum,	1.047	0.70	9.14 cry. al. sat. sol.
Sulphate of potash,	1.077	0.62	9.42 c. s. sat. sol. <
Muriate of potash,	1.168	0.61	26.0 c. s. sat. sol.
Sulphate of soda,	1.105	0.58	11.14 dry salt,sat. sol.
Nitre,	1.139	0.57	20.6 sat. sol.
Nitrate of soda,	1.206	0.45	26.4 sat. sol.
Sulphuric acid,	1.840	0.45	I
Tartaric acid,	1.285	0.41	53.37 c. acid, sat. sol.
Common salt,	1.212	0.329	29. s. sat. sol.
Muriate of lime,	1.402	0.261	40.2 ignited salt, sat. sol.
  Though the influence of the viscidity of
a liquid be small with regard to the amount
ofthe absorption, yet it increases the time
necessary for the  condensation of the gas.
In  general,  the  lightest liquids possess
the  greatest power of  absorbing  gases;
with the exception of those  cases  where
peculiar affinities interfere.
  5. Influence  of the  barometrical pres-
sure on the absorption  of gases by liquids.
  M. de Saussure shows that in liquids the
quantities of gases absorbed are as the com-
pressions; while in solid bodies, on the con-
trary, as the gases become less dense, the
absorption seems  to increase.  Dr. Henry
hadpreviously demonstrated,that the quan-
tity of carbonic acid taken up by water,  is
proportional  to the compressing force;  a
fact long ago well known and applied  by
Schweppe,  Paul,  and other manufacturers
of aerated alkaline waters.
  6. Simultaneous  absorption  of  several
gases by water.
  M. de Saussure thinks it probable, that
the absorption ofthe different gases at the
same time by liquids, is analogous to what
he observed  with respect to solid bodies.
Henry,  Dalton, Van Humboldt,  and Gay-
Lussac, had already remarked, that water
saturated with one gas, allows a portion of
that gas to escape, as soon as it comes in
contact with  another gas.  " It is indeed
evident, according to Dalton's theory," says
M. de Saussure, " that  two gases absorbed
into a liquid, should really  occupy always
the same room, as they would  occupy,  if
each of them had been absorbed singly, at
the degree of density which it has in  the
mixture." To obtain results on this sub-
ject,  approaching to accuracy,   he was
obliged to make mixtures, of carbonic acid
with oxygen, hydrogen,  and azotic gases;
for the last  three gases are absorbed  by
water, in so small a proportion, that the dif-
ferent condensations which take place, can-
not be confounded with errors in the expe-
riments.
   1. Water  and a mixture of equal mea-
sures of  carbonic acid and hydrogen gas.
   He brought 100 measures of water, at
the temperature of 62i°, in contact with
434 measures of equal volumes of carbonic
acid and  hydrogen. The absorption amount-
ed to 47.5 volumes, of which 44 were car-
bonic acid, and 3.5 hydrogen.  If we com-
pare  the space which the absorbed gases
occupy in the water, with that which they
would occupy, according to the preceding
table of  absorption of unmixed gases,  we
find that the presence of one of the gases
has favoured the absorption  of the  other,
as  far as the relative space  goes,  which
each  would  occupy separately in the water.
   2. Water  and a mixture of equal parts of
carbonic acid, and oxygen gas.
   100 volumes of water at 62$  degrees
absorbed from 390 volumes of this mixture,
52.1 volumes; of which 47-1  volumes were
carbonic acid, and 5 volumes oxygen gas.
Here also the condensation is greater than
when the gases are separate. 
GAS
GAS
   3. Water and a mixture of carbonic acid
gas and azote.
   100 volumes of water absorbed from
357.6 volumes of this mixture, at the above
temperature, 472  volumes;  of which  43.9
volumes were carbonic acid, and 3.3 azote.
   The results of these experiments, as we
perceive, agree completely with each other;
but none of them corresponds with Dalton's
theory, according to which,  the volume  of
carbonic acid absorbed, should be just one-
half of that of the absorbing  liquid; and
likewise the volumes of the other gases ab-
sorbed should be much smaller than M. de
Saussure  found them  actually to  be.  A
mixture of oxygen and hydrogen gases, in
the proportions for forming  water, by agi-
tation with that liquid, were absorbed  in
the proportion of  54, volumes to  100 vo-
lumes of the liquid.  In  an  appendix, M.
de Saussure describes  minutely the judi-
cious precautions  he took to insure preci-
sion of result; which leave little doubt  of
the accuracy of his experiments, and the
justness of his conclusions.  They  are  as
fatal to Mr.  Dalton's mechanical  fictions
concerning the relation of liquids and gases,
as MM. Dulongand Petit's recent research-
es have been to his geometrical fictions on
the phenomena of  heat.
   III. Of  Gaseous Analysis.
   This  department of chemistry,  whose
great importance was first  shown by Ca-
vendish, Priestley, and Uerthollet, has late-
ly acquired new value in consequence  of
M. Gay-Lussac's doctrine of volumes, his
determination of the specific gravities  of
vapours, and sagacious application of both
principles, to  the  developement of many
combinations hitherto intricate and inex-
plicable.
   Let us first  take a general view of the
characters of the  different  gases.  Some
of them are coloured, others diffuse white
vapours in the air; some  relume  a taper,
provided a point  of its wick remains ig-
nited; others are acid and redden tincture
of litmus; one set have no smell, or but a
faint one;  a second set are very soluble  in
water; a third are soluble in alkaline solu-
tions; and a fourth are themselves alkaline.
Some gases possess  several of these  cha-
racters at once.
   1. The  coloured gases  are nitrous acid,
chlorine,  the  protoxide and deutoxide of
chlorine.  The first is red, the rest yellow-
ish green, or yellowish.
   2. Gases producing white  vapours in the
air.   Muriatic acid, fluoboric,  fluosilicic
and  hydriodic.
   3. Gases imfiammable in air by contact of
the lighted taper.   Hydrogen,  subcarbu-
retted and  carburetted  hydrogen,  sub-
phosphuretted and phosphuretted  hydro-
gen, sulphuretted  hydrogen, arsenuretted
hydrogen, tellurettcd hydrogen, potassu-
retted hydrogen, carbonous oxide, prus-
sine or cyanogen.
  4. Gases which rekindle the expiring ta-
per.  Oxygen, protoxide of azote, nitrous
acid, and the oxides of chlorine.
  5. Acid gases, which redden litmus.  Ni-
trous, sulphurous, muriatic, fluoboric, hy-
driodic,  fluosilicic,  chlorocarbonous,  and
carbonic acids; the oxides of chlorine, sul-
phuretted hydrogen, telluretted hydrogen,
and prussine.
  6. Gases destitute  of smell, or possessing
but a feeble one.  Oxygen, azote,  hydro-
gen, subcarburetted and carburetted hy-
drogen, carbonic acid, protoxide of azote.
  7. The smell of all the others is  insup-
portable, and frequently characteristic.
  8. Gases very  soluble in water, namely,
of  which water  dissolves  more than 30
times its volume, at ordinary pressure and
temperature.  Fluoric acid, muriatic, fluo-
silicic, nitrous, sulphurous, and ammonia.
  9.  Gases  soluble  in  alkaline solutions.
Acids, nitrous, sulphurous, muriatic, fluo-
boric, hydriodic, fluosilicic, chlorine, car-
bonic, chlorocarbonous; and the two oxides
of chlorine, sulphuretted  hydrogen, tellu-
rettcd hydrogen, and ammonia.
  10. Alkaline gases.  Ammonia and po-
tassuretted hydrogen.
  Such is a general outline of the charac-
teristics of the gases.  The great problem
which now presents  itself is, to determine by
experiments  the nature of any single gas, or
gaseous mixture,  which  may come before us.
                    I.
  We  first fill a little glass tube with it,
and expose it to the action of a lighted ta-
per.  If it inflames, it  is one of  the 11
above enumerated,  and must  be discrimi-
nated by the following methods.
  1. If it takes fire  spontaneously on con-
tact with air, producing a  very acid mat-
ter, it is phosphuretted hydrogen.  Subphos-
phuretted hydrogen, or the bihydroguret
of phosphorus, does not spontaneously in-
flame.
  2. If water  be  capable of decomposing
it,  and transforming it suddenly into hy-
drogen gas and alkali, which we can easily
ascertain by  transferring the test tube fil-
led with it, from the mercurial trough, to
a glass  containing water, it is potassuretted
hydrogen.  I  found in my experiments on
the production of potassium,  by passing
pure potash over ignited iron turnings, of
which some  account  was  published in
1809, that potassuretted hydrogen  spon-
taneously inflamed.  M. ^ementini has made
the same observation.
  3. If  it has  a nauseous  odour, is  insolu-
ble in water, leaves  on the sides of the test
tube in which we burn it, a chesnut-brown
deposite, like hydruret of  arsenic, and if,
after agitation with  the quarter of its vo-
lume of aqueous chlorine, a liquid is form- 
GAS
GAS
 ed, from which sulphuretted hydrogen pre-
 cipilaus yellow flocculi,  it  is  arsenuretted
 hydrogen gas.
   4. it it lias a strong smell of garlic or phos-
 phorus, if it daes not inflame spontaneously,
 if the  product of its combustion  strongly
 reddens htm ;s, und if, on agitation with an
 exrvss of aqueous chlorine, a liquor results,
 wfr.ch, .tfter evapor.ition, leaves a very sour
 sirupy residuum,  it is  subphosphuretied hy-
 drogen.
   5.  If it has  no smell or but a faint one,
 and if it be capable of condensing one-half
 its  volume of owgen  in the explosive eudi-
 ometer, it is hydrogen.
   6.  It" it bus a faint  smell, be  capable of
 condensing in the explosive eudiometer one-
 half of its volume of oxygen, and of produc-
 ing a volume of carbonic acid equal to its
 own,  which is  ascertained by  absorbing it
 with  aqueous potasii, it is carbonous oxide.
   7.  If it lias a faint smeil, ii one ofthe pro-
 ducts ot  combustion is carbonic acid,  am: if
 the quantity of oxygen, which  it condenses
 by  the explosive eudiometer, corresponds to
 twici  or ihnce its volunu,  then it is either
 sub carburetted or carburetU d hydrogen.
  8. If it diffuses the odour ot  rotten eggs,
 if it blackens solutions of lead, if it leaves  a
 deposite of sulphur when we burn it  in the
 test tube, and it it be absorbable by potash,
 it is sirtphnretted hydrogen
  9. It it has a  fetid odour, approaching to
 that of sulphuretted hydrogen,  if  it  is ab-
 sorbable by potash, if it is soluble in water,
 if it forms with it a liquid, which,  on  expo-
 sure to air, It ts fall a brown pulverulent hy-
 druret of tellurium;  and lastly, if on  agita-
 tion with  an excess  of  aqueous  chlorine,
 there results a muriate of tellurium, yielding
 a white precipitate with alkalis, and a black
 with  the hy drosulphurets, it  is te'luretted
 hydrogen.
  lu. Prussine is known by its offensive and
 very  pecul.ar smell, and its burning with a
 purple flame.
                    II.
  If the  gas be  non-inflammable,  but ab-
 sorbable by an alkaline solution, it will be
 one ofthe 13 following: muriatic acid, fluo-
 boric, fluosilicic, hydriodic,  sulphurous, ni-
 trous, chlorocarbonous,  carbonic;  or  chlo-
 rine,  the  oxides  of chlorine, prussine, or
 ammonia.  The first four,  being  the only
 gases  which produce white  vapours with
 atmospheric  air, from their strong affinity
 for  water, are  thus  easily  distinguishable
 from  all others.  The fluosilicic gas  is re-
 cognized by the separation of silica, in  white
 flocculi,  by means of water; and  hydriodic
gas, because chlorine  renders it violet, with
the precipitation of iodine.
  Muriatic acid gas, from  its forming with
solution of silver a white precipitate insolu-
ble  in acids, but  very soluble in ammonia,
 and from its yielding  with oxide of manga-
      VOt. II,
 nese a portion of chlorine. Fluoboric gas, by
 the very dense vapours which it exhales, and
 by its instantly  blackening paper  plunged
 into it.   Nitrous acid gas is distinguished by
 its red colour. Protoxide of chlorine, because
 it is of a lively greenish yellow hue, because
 it exercises no  action on mercury at ordi-
 nary temperatures, and because,  on bringing
 ignited iron or glass in contact with it,  it is
 decomposed with explosion into oxygen and
 chlorine.
   Deutoxide of chlorine is of a still brighter
 yellowish-green than the preceding, and his
 a peculiar jromatic smell.   It does not red-
 den, but blanches vegetable blues.  At 2l2a
 it explodes, evolving oxygen and chlorine.
 Chlorine is distinguished by its fainter yel-
 lowish-green  colour,  by  its suffering  no
 change on being heated, by its destroying co-
 lours, and by its rapid combination with mer-
 cury at common temperatures.  Sulphurous
 acidby its smell of burning sulphur. Ammonia
 by its odour,  alkaline properties, and the
 dense white vapours it forms with gaseous
 acids.   Chlorocarbonous gas  is converted by
 a very small quantity of water into aqueous
 muriatic acid,  and carbonic acid which rests
 above. Zinc or antimony, aided by heat, re-
 solves it into carbonous oxide gas, while a
 solid metallic chloride is formed.  With tha
 oxides  of  the same  metals, it  forms chlo-
 rides, and carbonic acid, while in each case
 the quantity of gaseous oxide of carbon, and
 carbonic acid disengaged,  is equal to the
 volume of chlorocarbonous gas operated on.
 Carbonic acid gas is colourless,  and void  of
 smell, while  all the  other gases absorbable
 by the alkalis have a strong odour. It hardly
 reddens even  very dilute tincture of litmus;
 it gives a white cloud with lime-water, from
 which a precipitate falls, soluble with effer-
 vescence in vinegar.
                   III.
   If, finally, the gas be neither inflammable
 nor capable of being absorbed by a solution
 of potash, it will be oxygen, azote, protoxide
 of azote, or deutoxide of azote.  Oxygen can
 be inistiken only for the protoxide of azote.
 The property it possesses of rekindling the
 expiring wick of a  taper, distinguishes  it
 from  the two other gases.   They are more-
 over characterized, 1st,  15ccause oxygen is
 void of taste, and  capable of condensing in
 the explosive eudiometer, twice  its volume
 of hydrogen gas;  the protoxide of azote be-
 cause it has a sweet taste, is soluble in a little
 less than half its volume of cold water, and
 because when detonated with its own  vo-
 lume of hydrogen, we obtain a residuum,
 containing much azote. The two other gases.
are distingiiislied thus: Deutoxide of azote is
 colourless, aiul when placed in contact with
atmospherical air or oxygen, it becomes red,
passing to the  slate of nitrous acid vapour.
Azote  is  void  of colour, smell,  and  taste,
extinguishes combustibles, experiences no
                 11 
GAS
GAS
change on contact with air, and produces no
cloud with lime-water.
  Under the different gases, the reader will
find their discriminating characters minutely
detailed. We shall conclude this article with
a method of solving readily an intricate and
common problem  in  gaseous analysis, for
which no direct problem has I believe been
yet offered.  Allusion has been made to  it
in treating of coal gas, and the plan pointed
out in a popular way.
  Analytical problem.—In a mixture consti-
tuted like purified  coal gas, of three inflam.
made gases, such as olefiant gas, carburetted
hydrogen, and carbonous oxide, inseparable
by ordinary chemical  means,  to determine
directly the quantity of each.
  1. By the rule given at the  commence-
ment of the present article gas, find from the
specific gravity  of the mixed gases the pro-
portion of the  light carburetted hydrogen.
The remainder is the  bulk of the other two
gases  Detonate 100 measures of the mixed
gas with excess of oxygen  in an explosive
eudiometer. Observe the change of volume,
and  ascertain  the  expenditure of oxygen.
Of the ox\ «vn consumed, allow two volumes
for every volume of light carburetted hydro-
gen, sp. gr. 0.555, previously  found, by the
hydrostatic rule, to be present. The remain-
ing  volumes  of oxygen have gone to the
combustion of  heavy  carburetted hydrogen
or olefiant gas,  and carbonous oxide.  Then,
  Let m = measure of oxygen equivalent
             to 1 of first gas,
       n =    do. do. to 1 of second gas,
       p = measures of  oxygen actually
             consumed,
100  or s = volume of mixture of these two
             gases,
       x = volume of first gas,
    s—a; = volume of second gas.
            p— ns
        x =       .
            m—n

                Examples.

   \st  100 measures  of purified coal gas,
were found, by the hydrostatic problem,  to
contain 76 of subcarburetted hydrogen; and
exploded in the eudiometer, they were found
to consume 187 cubic inches of oxygen.  By
condensing with potash the  carbonic acid
formed, we  learn the volume  of residuary
 oxygen. But the solution of the problem is
otherwise independent ofthe quantity of car-
 bon c acid, generated in the present experi-
 ment.   We see from the table ofthe gases,
 that 1 volume  of olefiant gas is equivalent
 to 3 of oxj gen; and 1 volume carbonous ox-
 ide, to  oiu -half volume oxygen.  There-
 fore, deducting for the 76 ot subcarbonate,
 152 measures  of oxygen, the remaining  35
 have gone to the 24 measures of the two den-
 ser gases.  Hence
And  24 — 9.2 = 24.8. =  the carbonous
oxide.
  2d, 100 measures of a mixture of olefiant
gas, and carbonous oxide,  take 236 of oxy-
gen: What is the proportion of olefiant gas?

sorolefiant=236-(°-52^1Q0) -  744,

consequently 25.6 are carbonous oxide.
  This problem is applicable to every mix-
ture of two inflammable gases.  The hydro-
static problem I have been accustomed  for
years to apply to mixtures of  two gases,
whose specific gravities  are considerably
different, as carbonic acid and atmospheric
air; and with a delicate balance, and globe
containing 100 cubic inches, it gives a good
accordance with Chemical experiment.
  I employed this method for verification,
examining the air extracted  from the lungs
ofthe criminal's dead body, galvanized at
Glasgow in Nov. 1818.
  Generally, if we wish to get an approximate
knowledge of the proportion of two gases in a
mixture, we may adopt the  following plan.
Poise  the exhausted globe or flask at one
arm of a delicate balance.  Then, connect
its  stop-cock with the gasometer, bladder, or
jar, containing the  gaseous mixture. Intro-
duce an unmeasured quantity, great or small,
relative to the capacity of the globe-, for  it is
not necessary that the density of the air in
the gloj)e should be equal to that of the at-
mosphere.  In fact, it may happen, that the
whole quantity of the gaseous mixture may
not be equal to  more than  one-third, one-
half,  or three-fourths of the capacity of the
globe.  For instance, in the case of the  cri-
minal, I took a globe, capable of receiving
greatly more than the aerial contents of his
lungs.  An unknown quantity of the mixed
gases being now in  the globe, we suspend
it at the balance, and note  the  increase of
 weight.   We then open the stop-cock,  and
 allow the atmosphere to  enter, till an equi-
 librium of pressure ensues. The additional
 weight occasioned by the  atmospheric air,
 must be converted into bulk, at the rate of
 30.519 gr. for 100 cubic inches.   Deducting
 this bulk from the  known  capacity of our
 globe or flask, leaves a remainder, which is
 the volume of the  gaseous mixture first in-
 troduced; knowing  its  weight and volume,
 we infer  its specific gravity; and from its
 specific gravity, by the hydrostatic problem,
 we deduce the proportion of each gas in the
 mixture.
    IV. Of the  method  of determining the
 specific  gravity of gases,  and of the modifi-
 cation of their volume  from  variation of
 pressure and  temperature.—The specific
 gravity d' a gas is the weight  of a certain
 volume of it, compared to the same \ olume
 of air or water.  Air is now assumed as the
 standard for gases,  as water is for liquids;
 and the same  hydrostatic method  is appli-
 cable to  both elastic  and inelastic  fluids.
 We determine the specific gravity of a gas, 
GAS                                   GAS
With an air-pump, balance, and globe or flask,
having a  stop-cock attached to  its orifice.
We proceed thus:—We poise the  globe  at
the end of a balance, with its stop-cock
open: we next exhaust it, and weigh it  in
that state. The difference ofthe two weigh-
ings is the apparent  weight of the volume
of atmospheric air withdrawn from it.  We
verify that  first, estimate,  by opening the
stop-cock, and noting the increase of weight
occasioned by the ingress of the air.  Hav-
ing again exhausted, exactly to the same de-
gree, by the mercurial gauge, as before, we
poise.   This gives us for the third time, the
weight of air contained by the globe.   The
mean of the three trials is to be taken. We
now attach it,  by the screw ofthe stop-cock,
to a gasometer or jar,  containing gas desic-
cated by muriate of  lime over mercury,
and opening the communication, allow the
air  to enter till an equilibrium of  pressure
with the atmosphere is established. In this
stage ofthe operation, we must avoid grasp-
ing the globe  with our hands,  and  we must
see that the mercury in the inside  and out-
side of the jar stands truly on a level.   On
re-suspending the globe at the balance, we
find the weight of the included gas, which
being divided by the weight of the air for-
merly determined, gives a quotient, which
is the specific gravity of the gas in question.
When the utmost precision is required, we
should again exhaust the globe, again poise
it, and filling it with the gas, again  ascertain
its sp. gravity  under the bulk of the globe.
Even a third repetition is sometimes neces-
sary to secure final accuracy.   We should
always terminate the operations, by a  new
weighing of the atmospheric air, lest its tem-
perature or pressure may have changed du-
ring the  course  of the experiments.   It is
obvious, that  this method differs in no re-
spect from  that practised  long ago by the
Hon. Robert Boyle,  and by  Sir Charles
Blagden,  (See Alcohol,) with liquids, and
is that which, 1 suppose, every public teach-
er  of physics, like myself, explains  and
exhibits  annually to his pupils.  With re-
gard to liquids, it is necessary to bring them
to  a standard temperature, which in this
country is 60° F.  Bat, as the comparison
of gases with  air, is  always made at the in-
stant, our only care need  be, that the gas
and atmosphere are in the same state as  to
temperature  and  moisture, and  that the
equilibrium of pressure  be insured to the
gas, by bringing the liquid which confines
ft to a level, on the inside and outside of the
jar.
  If the gases stand over water, it is desira-
ble  to weigh them in somewhat cold weather,
when the thermometer is, for example,  at
40°; for then, the quantity of aqueous va-
pour they contain is  exceedingly small.   Or
otherwise, we  should place the atmospheric
air  we use for the standard of comparison
in the very same circumstances, over water,
at 60° for instance; and then with regard to
those gases whose density differs little from
that of the  atmosphere, no correction for va-
pour need be considered.
  From the experiments of M.  de Saussure,
and those of  MM. Clement and  I) sormes,
we  learn, that the same bulk of different
gases standing over water gives out, on be-
ing transmitted over dry muriate of lime, '■ he
same quantity of that liquid; which, for 100
cubic inches,  is, by  the first  philosopher,
0.35 of a grain troy at 57° F., and b\ the
second, 0.236 at 54°.  We shall, perhaps,
not err, by considering the v eight to be one-
third of a grain at 6u°.  Now, for luO cu-
bic  inches  of hydrogen, which in  the dry
state weigh only 2.118, one-third of a  grain
is nearly one-seventh of the whole, equiva-
lent to 14 cubic inches of dry gas.  But for
oxygen,  of which  100 cubic inches weigh
nearly 34 grains, one-third of a grain forms
only one 110th ofthe whole.
  The  quantity of moisture, present in air
or gas, at any temperature, may indeed be
directly determined from  my  table of the
elasticity of aqueous vapour.  If we  multi-
ply  19, which is the weight in grains of 100
cubic inches of steam ai 212°, by the  num-
ber 0.516 opposite 60° in my table,  we shall
have a  product, which, divided by 30, will
give a quotient,  = the weight  of  aqueous
vapour  in  100 inches of any  gas standing
over water at the given temperature.  Thus
19 X 0.516   nnm   ...  .
     „----= O.o27,  which is  very nearly

0.33, as stated above.  See infra.
  The  above plan of taking the specific
gravity  of gases, I believe to be the best, as
it was  the  earliest.  Having publicly  prac-
tised and taught it for 17 years, unconscious
of the  slightest merit, I was not a  little
amused at  perceiving this  old hydroslaiic
method recently claimed as a new discovery
or invention.
  We have seen, in treating of caloric, that
all gaseous matter changes its volume  by
one  48^th  part, for  the variation of  1° of
Fahrenheit's  thermometer.  This quantity
is in decimals = 0.0020833.  Hence,  if we
assume the volume to be equal to unity at
60°, and successively add or  subtract  that
decimal  quantity,  for every thermometric
degree  above or below that  temperature,
we  shall have the following table of reduc-
tion;—

TABLE of Reduction on  Gaseous Volumes,
  for Variations of Temperature above or be-
  low 60°, by  Dr. Ure.

  Temp.  Volume.      Temp. Volume.
    60°   1.000000     59°   1.002083
    61   0.997916      >8    1.004166
    C2   0.995833     57   1.006249 
GAS
GAS
Temp. 63*>	Volume.	Temi
	0.993750	56°
64	0.991666	55
65	0.989583	54
66	0.987500	53
67	0.985416	52
68	0.983333	51
69	0.981250	5U
70	0.979166	49
71	0.977083	48
72	0.975000	47
73	0.972916	46
74	0.970833	45
75	0.968750	44
76	0.966666	43
77	0.9645S3	42
78	0 962500	41
79	0.960416	40
80	0.958333	39
81	0.95625J	38
82	0.954166	37
83	0.952083	36
84	0.950000	35
85	0.947916	34
86	0.945833	33
87	0.943750	32
88	0.941666	31
89	0.939583	30
90	0 937500	29
91	0.935416	28
92	0.933333	27
93	0.931250	26
94	0.929166	25
95	0.927083	24
96	0.925000	23
97	0.922916	22
98	0.920833	21
99	0.918750	20
100	0.916666	
1.008333
1.010416
1.012199
1.014583
1.016666
1.018749
1.020833
1 022916
1.024999
1.0270K3
1.029166
1.031249
1.033333
1.035416
1.03749 i
1.039583
1.041666
1.043749
l.ii458.53
1.047916
1.049999
1-052083
1-054166
1-056249
1-U58333
1.060416
1.062499
 1.06:583
 1.066666
 l.o68749
 1 070833
 1.072916
 1074999
 1.077083
 1.079166
 1081249
 1.083333
          Use ofthe above Table.
  Opposite the temperature of the gas, we
find a number,  which  being multiplied into
the volume of the gas, however expressed,
gives the true  volume at 60°.  The  table
printed in some books, in which unitv  is
placed at 32°,  and 1.375 at  212°, can be
regarded merely as a specimen of  multipli-
cation.  In practical chemistry, we seldom
think of reducing experimental volumes to
the standard of 32° F.
   The bulk of  a gas being inversely as the
pressure, it will necessarily increase as the
barometer fulls, and  decrease as  it  rises.
Hence, to reduce the volume of  a gas at
any  pressure, to  what  it would  be under
the  mean pressure of 30 inches  of mer-
oury;  multiply the volume  by  the  parti-
cular barometrical pressure, and divide the
product by  30; the  quotient  is  the true
volume.   If the  gas  be  contained  in   a
vessel over mercury,  so that  the liquid me-
tal stands in the inside of the tube higher
than on the outside, it  is  evident that the
 g;is will  be  compressed by a less weight
 ilia.' the ambient atmosphere, in proportion
 IP the diflere.iiv ofthe mercurial  levels.   If
that difference were 10 inches,  then one-
third of the incumbent pressure would be
counterbalanced, and the- gas would become
bulkier by one-third.   Hence, we nnsi sub-
tract this difference of mercurial levels, from
the barometric altitude at  the instant, and
use this reduced number or remainder, as
the proper multiplier in the above rule. In-
stead of  reducing the volume of a gas to
what it would be under a mean press re of
30 inches, it is often  dcsiruMe to reduce it
to another barometrical height, which exist-
ed perhaps at the commencement of the ex-
periment d -nvestigation.  Thus, in applying
the eueliometer by slow combustion of phos-
phorus, we must  wait for 24 hours,  till the
experiment  be  fiimshed.  But  in  that pc-
nod, and in our fickle climate, the  mercury
of the barometer may have moved an inch
or more.  The general principle,  that the
volume is inversely as the pressure, measur-
ed by the length "of the mercurial column,
 affords the following  simple rule:—Multi-
 ply the bulk of the  gas  by  the  existing
 height ofthe barometer, and divide the pro-
 duct by the  original height, the quotient is
 its bulk as at the commencement of the ex-
 periment. The barometric pressure is esti-
 mated by the indies on its scale, minus the
 difference of mercurial  levels in the pneu-
 matic apparatus.  By bringing the  two sur-
 faces to one  horizontal plane, this correction
 vanishes.  The facility of doing so with my
 eudiometer, i^ one of"its  chief advantages.
   If we  are  operating in the water pneu-
 matic cistern, we  can in  general bring the
 two surfaces to  a level.   If not,  we must
 allow one inch  of mercurial pressure  for
 13.6 inches of water; and, of course, l-10th
 of a  barometical inch, for  every  inch and
 third of water.
   M. Gay-Lussac contrived a very ingeni-
 ous apparatus, to determine the  change of
 volume, which an absolutely dry gas under-
 goes,  when water is admitted to it, in mi-
 nutely successive portions,  till it (or the
 space it occupies) becomes saturated.   He
 deduced from these  accurate experiments,
 the following formula,  whose  results coin-
 cide  perfectly with  those  deducible from
 Mr.  Dalton's and  my  experiments  on the
 elastic force of aqueous vapour.
    When a perfectly dry gas  is admitted to
 moisture, its volume, v, augments, and be-
          v p
 comes —£—r; in which ti = the barometric
        P—J          '
 altitude, in inches, and/=  the elastic force
  of steam at the  given temperature.  Hence,
  100 cubic inches of dry air, weighing 30.519
  grains,  become  101.75,  when transferred
  over water  at  60°.  Therefore, 100 cubic
  inches of such aeriform matter, standing in
  a jar on the hydro-pneumatic trough,  must
  consist of,
     98.28 cubic  inches dry air = 29.99 gr.
       1.72 aqueous vapour      =  0.327gr. 
GAS                                    GAS
Weight of 100 cubic inches of
  air, over water at 60°       _ 30.3 If gr.
For hvdrogen we shall have,
    98'.28 inches dry gas   -   — 2.08157
     1.72 aqueous vapour      -= 0.32680
Weight of 100 cu. in. moist gas = 2.4o837
Heucu its sp. gr. compared  to that  of dry
              2.40837
air, will be — -|----—= 0.07891, and com-
               30.519
                      2.40837
pared  to moist  air -= .,   , _  = 0 07944.
                       o0.ol7
For chlorine we shall have (making  the sp.
gr. of tne dry gas = 2.5),
    98.28  cubic inches    -    — 74.9857
    1.72 aqueous vapour     -  —  0.3268

Weight of 100 cu. in. of moist chl. =» 75.3125
Hence, its sp.  gr. compared to that of dry

air, will be  =~ —' , ,   =» 2.4677, and com-
               3o.519
                       75.3125
pared  to  moist air =. -—^—— =» 2.48416.
1                      30.317
   'Sow,  the first is almost the density as-
signed  long ago by M.M.  Gav-Lussac  and
Thenard; on which, if we make the  correc-
tion for aqueous vapour present in it, on ac-
count of this gas never being collecte-d over
mercury, we shall have its true specific grav.
=— 2.5.   Sir H. Davy brought  out  a num-
ber still nearer 2.5, than that  of M.  G.y-
Lussac.   His  chlorine was probably  com-
pared with  air somewhat moist,  and  may
therefore be considered us readily reducible,
by a minute correction, to 2.5.  The reason
assigned by Dr. Thomson (Annals for Sept.
and Oct. 182o,)  for the  fo-iner erroneous
estimates of the sp. gravity  of that gas,  can-
not surely apply to the two  first chemists of
the age; namely, that the chlorine they  pre-
pared  as the standard of comparison, was
impure.   I think the true reason  is  that,
which I have now given.
   For defiant and carbonic  oxide gases, we
shall have,
    98.28 cubic  inches      -    = 29.1564
    1.72 vapour      -      -    =  0.3268
Weight of 100 cub. in.of moist gas = 29.4832
Hence, its sp. gr. compared to that of  dry
              29 4832
air, will be = -
0.966,  and  to
               30.519
            29.4832    „   „
moist air = -?---— — 0.9725.
            30.317

  Dr. Thomson appears to have  collected
his chlorine, olefiant gas, and carbonic oxide,
over water. Hence, his lute results on them,
if at 60- F. art erroneous; anil instead of
confirming ttie theore ical  numbers eled.ici-
ble from Higgii.s's  atomic doctrine, a.id M.
Gay-Lusstc's theory of volumes, they are in-
consistent with both. One might suppose that
he had prepared his apparatus for measuring
gaseous specific gravity, in the workshop of
lJiocrustes.  But far be it from me, to retort
on him, the insinuation which he throws out
agairfct  M. Thenard in his system of Che-
mis.ry,  vol. iv. p.  385:  "this result  ap-
proaches so nearly that of Lavoisier (Prout),
that there is reason to suspect that the coin-
cidence is more  than  accidental."  In fact,
Dr. Thomson's present experiments in the
above case, would prove a great deal too much.
Every result indeed Which  he sets down in
the above two journal';, is logically deduci-
ble from pre-existing facts, and in my appre-
hension, dfies not add an  iota to the strength
of their former evidence.  There are many
niceties lobe observed, before we can obtain,
by experiment, the exact densities of gaseous
matter.   On this subject the reader may
consult, with much advantage, Biot's Traitt
de Physique, vol.  1st,   where  geometry and
experiment go hand and hand, notwithstand-
ing  Dr. Thomson's condemnation of it, in
the following words:  " Indeed,  to be con-
vinced of the  little utility of mere mathe-
matical formulas, towards promoting this sci-
ence without  the  aid of experiment, the
reader has only to peruse the chemical part
of Biot's Traite de Physique,  where  he will
find abundance of specimens of most elabo-
rate mathematical investigations, which leave
every subject precisely in the state in which
they found it."  Annals  of Phil, for Sept.
182o.   Let me recommend to the doctor,
Biot's chapter on the sp. gr.  of gases,  and
not to vilify a book, by the unacknowledged
aid of which, he  has  given an air of origi-
nal research to his article Decomposition, in
the Supplement to the Enc Brit. 5th edit.*
  G siuic  Juice  is  separated  by glaiide
placed between the membranes which  line
the s-omacn;  anel from these it is emitted
into the stomach  itself.
   From various experiments it follows:
   1. That the gastric  juice reduces the ali-
ments into a uniform  magma, even out of
the body,  and in vitro;  and  that it  acts in
the same manner on the stomach afterdeath;
which proves that its effect is chemical, and
almost independent of vitality. 2. That the
gastric juice effects the  solution of the ali-
ments included in tubes  of metal, and con-
sequently defended from any trituration. 3.
That though there is  no trituration in mem-
branous stomachs, this action powerfully as-
sists the eliect  of ihe  digestive juices in ani-
mals with a muscular stomach, such as ducks,
geese, pigeons, See.  Some of these animals,
bred up with sufficient care that they might
not swallow stones, have nevertheless broken
spheres and tubes of metal, blunted lancets,
and rounded pieces of glass; which were in-
troduced  into their stomachs.  Spallan/.uni
has ascertained, that flesh, included in spheres
sufficiently strong to resist  the muscular ac-
tion,  was  completely digested.   4. That
gastric juice acts by its solvent power,  and 
GEO                                   GEO
not as a ferment; because the ordinary and
natural digestion is attended with no disen-
gagement of air, or inflation, or heat,  or, in
a word, with any other of the phenomena of
fermentation.
  * Gehlemte.  A mineral substance al-
fied to Vesuvian.  Its colours are olive-green,
leek-green, green of other  shades,  and
brown.  It occurs crystallized in rectangu-
lar four-sided prisms,  which are so short as
to appear tables.  Lustre glistening, often
dull.  Cleavage  imperfect,  but  three-fold
rectangular. Fracture fine splintery. Trans-
lucent on the edges.  Rather easily frangi-
ble.  Haider than feldspar, but softer than
quartz.   Sp. gr. 2. 98.  It melts before the
blow-pipe  into a  brownish-yellow  transpa-
rent glass.  It is found along with calcare-
ous spar in the valley of Fassa in the Tyrol.
Its constituents are, lime 35.5, silica 29.64,
alumina 24.8,  oxide  of iron 6.56, volatile
matter 3.3-*
  Gelatin, Gellt,  or  Jelly,  an animal
substance, soluble in water, capable  of as-
suming a well-known  elastic  or  tremulous
consistence by cooling,  when the water is
not too abundant, and liquefiable  again by
increasing its temperature.  This  last pro-
perty distinguishes it from albumen,  which
becomes  consistent  by heat.  It is precipi-
tated in an insoluble  form by tannin,  and  it
is this action of tannin on gelatin that is the
foundation ofthe art of tanning leather. See
Glue.
  * According to  the  analysis  of MM. Gay-
lkussac and Thenard gelatin is composed  of
       Carbon,       -       47.881
       Oxygen,      -       27.207
       Hydrogen,    -        7.914
       Azote,  -     -       16.998

                            100.000*
  Gems.  This word  is used to denote such
stones as are considered by  mankind as pre-
cious. These are the diamond, the ruby,
the sapphire,  the topaz, the chrysolite, the
beryl, the emerald, the hyacinth,  the ame-
thyst, the garnet, the tourmalin, the  opal;
and to these may be added, rock crystal, the
finer flints of pebbles, the cat's eye, the ocu-
lus mundi, or hydrophanes, the chalcedony,
the  moon-stone, the onyx, the carnelian,
the  sardonyx, agates,  and  the Labrador-
stone; for which, consult the several articles
respectively.
  Gkodes.  A kind  of jetites, the hollow of
which, instead  of a nodule, contains only
loose  earth, and is  commonly lined  with
crystals:
  * Geognosy.   See Geology*
  ♦Geology.  A description  of the struc-
ture  of  the earth.  This study may  be di-
vided, like most  others, into two parts; ob-
servation and theory.  By the first we learn
the relative positions of the great rocky  or
mineral aggregates that compose the crust
of our globe; through the second, we endea-
vour to penetrate into the causes of these
collocations.  A valuable work  has been
lately published, compnhending  a view of
both parts of the subject, by  Mr. Gree-nough,
to which I refer  my readers for much in-
struction, communicated in a very interest-
ing manner.  The plan of this work permits
me merely to  give in this place an  outline
ofthe general arrangement  ofthe great mi-
neral masses, as ascertained  by Werner, and
described by Professor Jameson.
  There is a great class of rocks, which lies
under  every other,  but never over any of
them;  it is  therefore reckoned by Werner
the  oldest or first formed.  It  is denomi-
nated the primitive class. The rocks belong-
ing to  this class,  have a crystalline appear-
ance, inelicating that they have been precipi-
tated from a state of chemical solution. They
are principally  composed of siliceous, argil-
laceous,  and  magnesian  earths  Granite,
gneiss,mica-slate,clay-slate,serpentine, por-
phyry, and syenite, are of this kind. Of these,
granite is the oldest, and syenite is the new-
est.
   To  this  succeeds  another  considerable
class of rocks, which Werner denominates
transition.  In this class, which is principally
composed of chemical productions, mechan-
ical depositions first make their appear-
ance, but in the earlier part, in inconsidera-
ble quantity.
   Limestone  first occurs  in  considerable
quantity in this class.
   Graywacke, graywacke slate, and transi-
tion limestone, are the predominating rock9
of this class.
   Still newer, and consequently lower, than
the  transition class, is the extensive  class
of floetz rocks.  Here mechanical deposites
occur  in great quantity, and the proportion
of chemical precipitate decreases.  The prin-
cipal rocks are limestone and sandstone; to
these may be added gypsum, salt, and great
accumulations  of inflammable matter in the
state of coal.
   Still newer and lower is the class of allu-
vial rocks,  which are almost entirely com-
 {>osed of mechanical deposites.  Sand, clay,
 oam, and coal, are the principal earthy mas-
ses that belong to this class.
   The newest of all, is the  class of volcanic
rocks.  Different kinds ot  lava and tuff in-
clude  nearly all the variety  of rocks belong-
ing to this class.
   in the first class, we observe several rocks
always disposed in conformable and unbro-
ken stratification, and in which the newer
and newer  strata, have always a lower and
lower  level.   Gneiss, mica-slate, and clay-
slate, are of this kind. The granite  stretch-
es under them uninterruptedly, and some-
times  rises up through them, or juts up  in
the form of single caps or great masses;  so
that the gneiss, and other rocks, are disposed 
GEO                                   GEO
•n its surface, sometimes in a concave, some-
times in a convex direction; sometimes sad-
dle shaped,  and frequently  mantle-shaped.
It is evident, from the relations of  the stra-
ta,  that  granite  will frequently form the
greatest heights on the surface of the globe.
  Porphyry has  a  very  different  kind  of
Stratification from the preceding rocks   It
occurs sometimes broken,  sometimes un-
broken.  When broken, it presents  caps,
upfillings, and  shield-shaped stratifications.
When unbroken, it  forms widely extended
masses.  Its position is  unconformable and
werlying.
  Graywacke  occurs sometimes in an un-
conformable position; also in caps, upfillings,
and shield-shaped,  and frequently mantle-
shaped strata,  surrounding the older moun-
tains.
  The limestone and sandstone formations
are usually disposed in a manUe-shape around
the older formations; sometimes they are bro-
ken, but more frequently unbroken.  They
are very common and widely distributed for-
mations.
  Coal again shows a very peculiar charac-
ter.  Its original extent is not considerable;
it even appears interrupted and broken; but
its internal characters show  that its present
apparently broken appearance is its original
one.  It occurs commonly in trough and ba-
sin-shaped hollows, and its strata have con-
sequently a concave  direction.
  The rocks of the neivest floetz-trap forma-
tion are distinguished from the  older  by
their unconformable overlying, and broken
stratification. In these respects, they nearly
agree with porphyry.  When the continuity
of the formation is broken, it occurs in caps,
upfillings, and rarely shield-shaped.

    Table ofthe different Mountain Rocks.

                 Class I.
              Primitive rocks.
  1. Granite.
  2  Gneiss.
  3. Mica-slate.
  4. Clay-slate.
  5. Primitive limestone.
  6. Primitive trap.
  7. Serpentine.
  S. Porphyry.
  9. Syenite.
10. Topaz-rock.
11. Quartz-rock.
12  Primitive flinty-slate.
13. Primitive gypsum.

14 White-stone.

                Class II.
             Transition rocks.
  1. Transition  limestone.
  2. Transition  trap.
  3. Graywacke.
 4. Transition flinty-slate.
 5. Transition gypsum.

               Class III.
              Floetz rocks.
 1. Old red sandstone, or first sandstone for-.
      mation.
 2. First or oldest floetz hmestone.
 3. First or oldest floetz gypsum.
 4. Second or variegated sandstone forma-
      tion.
 5 Second floetz gypsum.
 6. Second floetz limestone.
 7. Third floetz limestone.
 8. Rock-salt formation.
 9. Chalk formation.
10. Floetz-trap formation.
11. Independent coal formation.
12. Newest floetz-trap formation.

               Class IV.
             Alluvial rocks.
 1. Peat.
 2. Sand and gravel.
 3. Loam.
 4. Bog-iron ore.
 5. Nagelfluh.
 6. Calctuff.
 7. Calc-sinter.

                Class V.
             Volcanic rocks.
         * Pseudo-volcanic rocks.
 1. Burnt clay.
 2. Porcelain jasper.
 3. Earth slag.
 4. Columnar clay ironstone.
 5. Polier, or polishing slate.
          ** True volcanic rocks.
 1. Ejected stones and ashes.
 2. Different kinds of lava.
 3. The matter of muddy eruptions.

  Professor Jameson  has lately announced
a new volume on geology,  which will most
probably exhibit some modification of the
above arrangements,  to which Mr.  Gree-
nough, and other accurate practical geolo-
gists, have made several objections.
  The ancient history of the globe, which
may  be regarded as the ultimate object of
geological researches, is undoubtedly one of
the most curious subjects  that can engage
the attention of enlightened men.  The low-
est and most level parts of the earth, whea
penetrated to a very great depth, exhibit no-
thing but horizontal strata, composed of va-
rious  substances, and  containing  almost all
of them  innumerable  marine  productions.
Similar strata, with the same kind of produc-
tions, compose  the  hills even to a great
height.  Sometimes the shells are so nume-
rous as to constitute the entire body ofthe
stratum.  They are almost every-where in
such a perfect state of preservation, that even
 he smallest of them retain their most deli- 
                GEO

aate parts, their sharpest v'".Ves, and tendep-
est processes.  Tnev are found in elevations
far above the level of every part ofthe ocean,
and in plates to which the s a could not be
conveyed by am presently existing cause.
They are not merdy enclosed in loose s.uul,
but are often increased and penetrated on all
sides  bv the hardest stones.  Every part of
the earth,every hemisphere, every continent,
every island of anv size, exhibits the same
phenomenon.  We  are  therefore forcibly
led to believe, not only  that the sea has at
one period or another covered all our plains,
but that it must have remained there for a
long  time, and  in  a state  of tranquility;
which circumstance was  necessary  for the
formation of deposites so ext ensive, so thick,
in part so solid, and containing exuviae so
perft ctly preserved.  A nice and scrupulous
comparison of the  forms, contexture, and
composition of these  shells,  and of  those
which still  inhabit the sea, cannot  detect
the slightest difference between them.  They
have therefore once lived in the sea, and
been  deposited by it;  the sea consequently
must  have  rested in  the places where the
deposition has taken place.  Hence it is evi-
dent, that the basin or reservoir containing
the sea has undergone some change, either
in extent, situation, or both.
   The traces  of revolutions  become still
more apparent and decisive, when we ascend
a little higher, and approach  nearer to the
foot ofthe great chain of mountains.  There
are still found many beds of shells;  some of
these are even larger and more solid; the
shells are quite as numerous, and as entirely
preserved; but they are  not  of  the same
species with those which were found in the
less elevated  regions.   The  strata which
contain them are- not  so  generally horizon-
tal; they have various degrees of inclination,
and are sometimes situated vertically. While
in the plains and low hills it was necessary to
dig eleep in order to detect the succession of
the strata; here we perceive them by means
ofthe valleys, which  time or violence has
produced,  and which disclose  their  edges
to the eye of the observer.
   Thus the sea, previous to the formation
ofthe horizontal strata, had formed  others,
which by some means  have been  broken,
lifted up, and  overturned in  a thousand
ways. But the sea has not alway s deposited
stony substances of the same kind.   It has
observed a regular succession as to the na-
ture of its deposites; the more ancient the
strata are, so much the more uniform and ex-
tensive are they; and the more recent they
are, the more limited are they, and the more
variation  is observed in  them at small dis-
tances.  Thus the great catastrophes which
have produced revolutions in  the basins of
the sea, were preceded, accompanied, and
followed by changes  in the  nature of the
fluid, and of the substances which it held m
                 GIL

solutioa; and when the surface of the sea*
came to be divided hy islands and projecting
ridges, different changes took place in every
separate basin.
  These irruptions and retreats  of the sea
have neither been slow nor gradual; most of
the catastrophes which have occasioned them
have been sudden; and this is easily proved,
especially with regard to the last of them,  or
the Mosa'ic deluge, the traces of which are
very conspicuous.   In the northern regions
it has left the carcases of some large quadru-
peds, which the ice had arrested, and winch
are preserved even to the present day, with
their skin, their  hair,  and their flesh.  If
they had not been frozen  as soon as killed,
they must have been quickly decomposed by
putrefaction. But this perpetual frost could
not have taken  possession  of the  regions
which these animals inhabited, except by the
same cause which elestroyed them; this cause
must therefore have been  as sudden as its
effect.   The two most remarkable pheno-
mena of this kind, and which must for ever
banish all idea of a slow and gradual revolu-
tion, are the rhinoceros, eiiscovered in 1771
on the banks of the  Vilhoui,  and the ele-
phant,  recently  found by  M. Adams near
the mouth of the Sena.  This last retained
its flesh and skin, on which was hair of two
kinds; one short, fine, and crisped, resemb-
ling wool; and the other like bristles.  The
flesh was still in such high preservation, that
it  was eaten by dogs.  Every part  of the
globe bears the impress of these great and
terrible events so distinctly, that they must
be visible to all who are qualified to  read
their history in the remains which they have
left  behind.—See  Cuvier's Tlieory  of the
Earth.
  1 shall conclude this article  by stating,
that this naturalist, the most learned of the
present day, as  well  as  Dolomieu,  Deluc,
and Greenough, concur in thinking that not
above 5000 or 6000 years have elapsed since
the period of the deluge, which arrets with
the Mosaic epoch of that catastrophe.*
  * Germination.  The vital developement
of a seed, when it first begins to grow.*
  Gilding.   The art  of  covering the sur-
faces of bodies with gold.
  The gold prepared  for  painting is called
shell-gold or gold-powder, and may be ob-
tained by amalgamating one  part of gold
with eight of quicksilver, and afterward eva-
porating the latter, A'hich leaves the gold in
the form of powder; or otherwise the metal
may be  reduceel to powder by mechanical
trituration.  For this purpose, gold leaf must
be ground with honey or strong gum-water
for a long  time; and when the powder is
sufficiently fine,  the honey or gum may  be
washed off with water.
   For cold gilding by friction,  a fine linen
rag is steeped in a saturated solution of gold
titt it has entirely imbibed the liquor; this 
GIL                                    GIL
rag is then dried over a fire, and afterward
burned to tinder.  Now, when any thing is
to be gilded, it must be previously well bur-
nished; a piece of cork is then to be dipped,
first into a solution  of salt in water, and af-
terward into the black powder; and the piece,
after it is burnished, rubbed with it.
  For water gilding, the solution of gold
may be evaporated till  it is of an oily  con-
sistence, suffered to  crystallize, and the crys-
tals dissolved in water be employed instead
of the acid solution.   If this  be copiously
diluted with alcohol, a piece of clean  iron
will be gilded by being steeped therein. Or
add to the solution about three times its
quantity of sulphuric ether, which will soon
take up the nitro-muriate of gold,  leaving
the acid colourless at the bottom ofthe ves-
sel, which must then be drawn off.   Steel
dipped into the ethereal  solution for a mo-
ment, and instantly  washed in clean water,
will  be completely  and beautifully covered
with gold.   The surface of the steel  must
be well polished, and wiped very clean.
  For the  method  called Grecian gilding,
equal parts of sal ammoniac and corrosive
sublimate are dissolved in nitric acid, and a
solution of gold is made in this menstruum;
upon  this the  solution is somewhat concen-
trated, and applied  to the surface of silver,
which becomes quite  black;  but on being
exposed to a red heat, it assumes  die ap-
pearance of gilding.
  The method of gilding silver, brass, or
copper, by an  amalgam, is as follows: Eight
parts of mercury, and one of gold, are incor-
porated together by heating them in a cruci-
ble.   As  soon as the gold is perfectly dis-
solved, the mixture is poured into cold wa-
ter, and is then ready for use.
  Before the amalgam  can be laid upon the
surface of the metal, this last is brushed over
with dilute aquafortis, in  which it is of ad-
vantage that some  mercury may have been
dissolved.  Some artists then wash the me-
tal in  fair  water, and  scour it a little with
fine sand, previous to the application ofthe
gold; but others apply it to the metal while
still wet with the aquafortis.  But in either
case the  amalgam must be laid on  as  uni-
formly as possible,  and spread very evenly
with a brass-wire brush, wetted from time to
time  with  fair water.   The piece  is then
laid upon a grate, over a charcoal fire, or in
a small oven or furnace adapted to this pur-
pose. The  heat drives off the mercury, and
leaves the gold behind.  Its defects are then
seen,  and may be  remedied by successive
applications of more amalgam, and addi-
tional application of heat. The expert ar-
tists however,  make these additional appli-
cations while the piece remains in the fur-
nace, though the practice is said to be highly
noxious on account of the mercurial fumes.
After  this  it is rubbed with gilder's wax,
which may consist of four ounces of bees'
wax, one ounce of verdigris, and one ounce
  Vol.  II.
of sulphate of copper; then expose it to a
red  heat, which burns  off the  wax; and,
lastly,  the work is cleared with the scratch
brush, and burnished, if necessary, with a
steel tool.  The use  of  the  wax seems to
consist merely  in covering defects, by the
diffusion of a quantity of red oxide of cop-
per, which is left behind after the burning.
  The gilding  of iron by mere heat is per-
formed by cleaning and  polishing its sur-
face, and then heating it till it has acquired
a blue colour.  When this has been done,
the first layer of gold leaf is put on, slightly
burnished down,  and exposed to a gentle
fire.  It is  usual to give three such layers,
or four at the most, each consisting of a
single  leaf for common  works, or two for
extraordinary ones.  The heating is repeat-
ed at each  layer, and last of all the work
is burnished.
  The gilding of buttons is done in the fol-
lowing way: When the buttons,  which are
of copper, are  made, they are dipped into
dilute  nitric acid to clean them, and then
burnished with a hard black stone.  They
are then  put into a nitric solution of mer-
cury, and stirred about with a brush, till
they are  quite white.  An amalgam of gold
and mercury is then put into an earthen
vessel with a small quantity of dilute nitric
acid, and in  this  mixture the buttons are
stirred, till the gold attaches  to their sur-
face.  They are then heated over the fire,
till the mercury begins to run, when they
are thrown into a large cap made of coarse
wool and goat's hair, and in  this they are
stirred about with a brush.   The mercury
is then volatilized by heating over the fire
in a pan, to the loss of the article, and in-
jury of the workmen's health; though the
greater part might be recovered, with less
injury to the operators.  By  act of parlia-
ment, a gross of buttons, of an inch diame-
ter, are required to have five grains of gold
on them; but many  are deficient  even of
this small quantity.
  Painting  with  gold  upon  porcelain or
glass is  done  with  the powder of gold,
which  remains  behind after distilling, the
aqua regia from a solution of that metal.
It is laid on  with borax and gum-water,
burned in,  and  polished.  The gilding of
glass is commonly effected by covering the
part with a solution of borax, and applying
gold leaf upon  it, which is afterwards fixed
by burning.
  Gilding in  oil is performed by means of
a paint sold under the name  of  gold size.
It consists of drying oil, (that is to say, lin-
seed oil boiled  upon litharge), and mixed
with yellow  ochre.  It  is said to improve
in its quality by keeping. This is laid upon
the work; and when it has become  so  dry
as to adhere  to the fingers without soiling
them, the gold  leaf is laid on, and pressed
                      12 
GLA                                 GLA
down with cotton.  This method of gild-
ing is proper for work intended to be ex-
posed to the weather.
   The method of gilding in burnished gold
consists in covering the work with parch-
ment size and whiting, thinly laid on at five
or six  different times.  This is covered
with a yellow size made of Armenian bole,
a little wax, and some  parchment size; but
in this,  as in most other compositions used
in the arts, there are variations which de-
pend on the skill or the caprice of the  ar-
tists.  When the size  is dry, the gold  is
applied upon the surface  previously wet-
ted with clear water.  A  certain number
of hours after this application, but  previ-
ous to the perfect hardening of the  com-
position, the gold may be very highly bur-
nished with a tool of agate made for this
purpose.  This gilding is fit only for work
within doors; for it readily comes off upon
being wetted.
   The edges of the leaves of books are
gilded by applying a  composition of one
part Armenian bole, and one quarter of a
part of  sugar-candy, ground together with
white of eggs.   This is burnished  while
the book  remains in the   press, and the
gold is laid on by means of a little water.
   Leather is gilded either  with leaf-brass
or silver, but most commonly by the latter,
in which case a gold coloured varnish  is
laid over the metal.  Tin-foil may be used
instead of silver leaf for this less perfect
gilding upon such works as do not possess
flexibility.
   • Glass.  Most of the  treatises, which
I have seen on  the manufacture  of glass,
illustrate a well known position, that it is
easy to  write a large volume, which  shall
communicate   no  definite  information.
There are five distinct kinds  of glass at
present manufactured:—
   1. Flint glass, or glass of lead.
   2. Plate glass, or glass of pure soda.
   3. Crown glass, the best window-glass.
   4. Broad glass, a coarse window-glass.
   5. Bottle, or coarse green glass.
   1. Flint Glass, so named  because the sili-
ceous ingredient was originally employed
in the form of ground flints.  It is now
made of the following  composition:—
       Purified Lynn sand,  100 parts
       Litharge or red lead, 60
       Purified pearl ash,    30
  To correct the green colour derived from
combustible matter, or oxide of iron, a lit-
tle black oxide of manganese is added, and
sometimes nitre and arsenic The fusion is
accomplished usually in about thirty hours.
  2. Plate Glass.  Good carbonate of soda
procured  by decomposing  common salt
with pearl ash, is employed as the  flux.
The proportion of  the materials is,
     Pure sand,......430
     Dry subcarbonate of soda, - 26.5
     Pure quicklime,   -  -   -  -  4.
     Nitre,........1-5
     Broken plate* glass,   -   -  - 25.0

                               100.0
  About seventy parts of good plate glass
may be run off from these materials.
  3. Crown, or fine Window-glass.  This is
made of sand vitrified by the impure baril-
la,  manufactured  by incineration  of sea-
weed, on the Scotch and Irish shores. The
most improved composition, is
                   By measure. By weight.
  Fine  sand purified,     5        200
  Best  kelp ground,     11        330
  These ingredients are mixed, and then
thrown  into  the  fritting arch, where the
sulphur of the kelp is dissipated, and the
matters are thoroughly incorporated, form-
ing, when withdrawn at the end  of four
hours, a grayish-white tough mass, which
is cut into brick-shaped pieces, and after
concretion and cooling,  piled  up for use.
By long keeping, a soda efflorescence forms
on their surface.  They  are then supposed
to have become more  valuable.   These
bricks  are put into the melting pots, and
sometimes a proportion  of common salt is
thrown  in towards the  end of the opera-
tion, if the vitrification has been imperfect.
Under the article sulphate of soda, in this
Dictionary, retained from the old edition,
there is the following sentence: " Pajot des
Charmes has made some  experiments on
it in fabricating glass; with sand alone, it
would not succeed, but equal parts of car-
bonate  of lime, sand, and dried sulphate
of soda, produced a clear, solid, pale-yel-
low glass."  In the Annals  of Philosophy
for Jan. 1817, we find the following notice
from Schweigger's Journal,  xv. 89.: Geh-
len, some time before his death, was occu-
pied with experiments on the preparation
of glass,  by  means of  sulphate of soda.
Professor Schweigger has lately published
the result of his trials.  He found that the
following proportions were the best:—
  Sand,                      100
  Dry sulphate of soda,   -     50
  Dry quicklime in powder,     17 to 20
  Charcoal,    -    -     -      4
  This  mixture always gives a very good
glass without any addition whatever. Dur-
ing the fusion, the sulphuric acid is decom-
posed and drawn off, and  the soda unites
with the silica.  The sulphate of soda vi-
trifies very imperfectly, when mixed alone
with the silica. The vitrification succeeds
better when  quicklime  is  added, and it
succeeds completely, when the proportion
of charcoal in the formula is added; be-
cause the  sulphuric acid is thereby de- 
GLA                                 GLA
 composed and dissipated.  This decom-
 position may be either effected during the
 making of the glass, or before, at the plea-
 sure of the workmen.
   4. Broad Glass.  This is made of a mix-
 ture of soap  boilers' waste, kelp, and sand.
 The first  ingredient consists of lime used
 for rendering the alkali of the soap boiler
 caustic, the insoluble matter  of his kelp
 or barilla, and a quantity  of salt  and  wa-
 ter, all in a pasty state.   The  proportions
 necessarily  vary.   2 of  the  waste, 1 of
 kelp, and 1 of sand, form a  pretty good
 broad glass.   They  are  mixed  together,
 dried, and fritted.
   5. Bottle Glass is the coarsest kind.  It
 is made of soaper's waste and river sand,
 in proportions  which practice must deter-
 mine according  to  the  qualtity  of  the
 waste; some  soap boilers extracting more
 saline matter,  and others  less from their
 kelps.  Common sand and  lime, with  a
 little common  clay and  sea salt,  form  a
 cheap mixture for bottle glass.*
   As far as observation has hitherto direc-
 ted us, it  appears to be a general rule, that
 the  hardness,  brittleness, elasticity,  and
 other mechanical  properties  of congealed
 bodies, are greatly affected by the degree
 of rapidity with  which they assume  the
 solid state.   This, which  no  doubt is re-
 ferable to the property of crystallization,
 and its various modes, is remarkably seen
 in steel and other metals, and seems to
 obtain in glass.   When a  drop of glass is
 suffered to fall into  water, it  is found to
 possess the remarkable property of flying
 into minute pieces, the instant a small part
 of the tail is broken  off.   This, which is
 commonly distinguished by the  name of
 Prince Rupert's drop, is similar to the phi-
 losophical phial; which is a small vessel of
 thick glass suddenly cooled  by exposure
 to the air.  Such a vessel possesses  the
 property  of  flying  in pieces, when  the
 smallest piece of flint or angular pebble is
let fall into it, though a leaden bullet may
 be dropped into it from some height with-
out injury.  Many explanations have been
offered, to account for these and  other si-
milar appearances, by referring to  a sup-
posed  mechanism or arrangement of the
particles,  or  sudden confinement of  the
matter  of heat.    The immediate cause,
however, appears to be derived from  the
fact, that  the  dimensions of  bodies sud-
denly cooled remain larger, than if the re-
frigeration had  been more gradual.  Thus
the specific  gravity of steel hardened by
sudden cooling in water is less, and its di-
mensions  consequently greater than that
of the same steel gradually cooled.  It is
more than probable, that an effect of  the
same nature obtains in glass; so  that  the
dimensions of the external and suddenly-
cooled surface remain laiger than are suit-
 ed to the accurate envelopement of the in-
 terior part, which is  more slowly cooled.
 In most of the metals, the degree of flexi-
 bility they possess, must be  sufficient to
 remedy this inaccuracy as it  takes place;
 but in  glass,  which, though  very elastic
 and flexible, is likewise excessively brittle,
 the  adaptation of the parts, urged different
 ways by their disposition to  retain  their
 respective dimensions and likewise to re-
 main in contact, by virtue of the cohesive
 attraction, can  be maintained only by  an
 elastic yielding  of the  whole, as far as may
 be, which  will therefore remain in  a  state
 of tension. It is not therefore to be  won-
 dered at, that a solution of continuity  of
 any  part of the surface should destroy this
 equilibrium of elasticity; and that the sud-
 den action of all the parts at once, of so
 brittle a material, should destroy the con-
 tinuity of the whole, instead of producing
 an equilibrium of any other kind.
   Though the facts relating to this dispo-
 sition  of glass  too  suddenly  cooled, are
 numerous and interesting to the philoso-
 pher, yet  they  constitute a  serious evil
 with respect to the uses of this  excellent
 material. The remedy of the glass-maker
 consists in annealing the  several articles,
 which is done  by placing them in a furnace,
 near the furnace of fusion.  The glasses
 are first put into  the  hottest part of this
 furnace, and  gradually   removed  to the
 cooler parts at  regular  intervals of time.
 By this means the glass cools very slowly
 throughout, and is in a great measure free
 from the defects of glass  which has  been
 too hastily cooled.
   M. Reaumur was the first who made any
 direct experiments upon  the conversion  of
 glass into porcelain.  Instances of this ef-
 fect  may be observed among the rubbish
 of brick-kilns, where pieces of green bot-
 tles are not unfrequently subjected  by ac-
 cident, to the  requisite heat;  but the di-
 rect  process  is  as follows:  A vessel  of
 green glass is  to be filled up to the top
 with a mixture of white sand and gypsum,
 and then set in  a large  crucible upon a
 quantity of the same mixture, with which
 the glass vessel  must  also be  surrounded
 and covered over, and  the whole pressed
 down rather hard. The crucible is then to
 be covered with  a lid, the junctures  well
 luted, and put into a potter's kiln,  where
 it must remain during the whole time that
the  pottery is baking; after  which, the
 glass vessel will  be found  transformed in-
 to a milk-white porcelain,  The glass, on
 fracture, appears fibrous, as if it were com-
 posed merely of silken  threads laid by the
 side  of each other: it has  also quite  lost
the  smooth and shining appearance of
 glass, is very  hard, and emits sparks of
fire when struck with steel; though not so
briskly as real porcelain.  Lewis observed, 
                 GLA

that the above-mentioned materials  have
not exclusively this effect upon  glass; but
that powdered charcoal, soot, tobacco-pipe
clay, and bone-ashes,  produce the  same
change.  It is remarkable,  that the sur-
rounding sand becomes in some measure
agglutinated by  this  process,  which,  if
continued for a  sufficient length of time,
entirely destroys the texture of the glass,
and renders it pulverulent.
  The ancient  stained  glass  has  been
much admired, and beautiful paintings on
this substance have been produced of late
years.   The colours  are of  the nature  of
those used in enamelling, and the  glass
should have no lead in its composition. Mr.
Brongniart  has  made many experiments
on  this subject.  The purple of Cassius,
mixed with  six parts of a flux, composed
of borax, and glass made with silex and
lead, produces a very beautiful violet, but
liable to turn blue.   Red oxide of iron,
prepared by means of the nitric  acid and
subsequent  exposure to fire,  and mixed
with a  flux of borax,  sand, and a small
portion of minium,  produces a fine red.
Muriate of  silver, oxide of zinc, white
clay, and the yellow  oxide of iron, mixed
together without any flux, produce a yel-
low, light or deep, according to the quan-
tity laid on, and  equal in beauty to that  of
the ancients.  A powder remains  on the
surface after baking, which may easily be
cleaned off.  Blue is produced by oxide  of
cobalt,  with a flux  of silex, potash, and
lead.  To produce a  green, blue must  be
put on one side of the glass, and yellow
on the other; or a blue may be mixed with
yellow oxide of iron.   Black is  made by a
mixture  of blue with the oxides of man-
ganese and iron.
  The bending of the glass,  and alteration
of the colours, in baking, are particularly
to be  avoided,  and  require much  care.
Gypsum has been recommended for  their
support, but this  frequently renders the
glass white, and cracked in  all  directions,
probably from  the action of the hot sul-
phuric acid on the alkali in the glass.  Mr.
Brongniart placed his plates  of glass, some
of them much larger than any ever before
painted, on very smooth plates of earth  or
porcelain unglazed,  which  he  found  to
answer extremely well.
  * Glauber Salt.  Native sulphate  of
soda.  Its colours  are  grayish and  yellow-
ish-white.   It occurs in mealy  efflores-
cences, prismatic  crystals,  and imitative
shapes.  Lustre vitreous.  Cleavage three-
fold.  Fracture  conchoidal.  Soft.  Brit-
tle.  Sp. gr.  2.2 to 2.3. Taste at first cool-
ing, then saline and  bitter. Its solution
does not, like that of Epsom salt, afford a
precipitate with an alkali.  Its constituents
are, sulphate of soda 67; carbonate of soda
16J-; muriate of soda 11; carbonate of lime
                GLU

5.64.  It occurs along with rock salt  and
Epsom salt, on the borders of salt  lakes,
and dissolved in the  waters of lakes  and
the ocean; in efflorescences  on  moorish
ground; also on sandstone, marl-slate, and
walls.  It is found at Eger in  Bohemia, on
meadow-ground, as an efflorescence,  and
in galleries of mines in several places.*—
Jameson.
   * Glauberite.  Colours grayish-white,
and wine-yellow.  Crystallized in very low
oblique four-sided   prisms,   the  lateral
edges of which  are  104° 28', and 75° 32'.
Lateral planes transversely streaked; ter-
minal planes  smooth.  Shining.  Fracture
foliated or conchoidal.  Softer than calca-
reous  spar.  Transparent.   Brittle.   Sp.
gr. 2.7-  It decrepitates  before the blow-
pipe, and melts into white enamel.  In wa-
ter it becomes opaque, and is partly solu-
ble.  Its constituents are, dry sulphate of
lime 49; dry sulphate of soda  51.  It is
found imbedded in rock-salt, at  Villaruba,
near Ocana,  in New Castile in Spain.*—
Jameson.
   Glazing.  See Pottery.
   Glimmer. A name occasionally applied
to micaceous earths.
   * Gliadine.  See Gluten.*
   Glucina.  This  earth was  discovered
by Vauquelin, first in the aqua marina, and
af'terward in the emerald, in  the winter of
1798.  Its name is derived from its distin-
guishing character  of forming with acids,
salts that  are sweet to the taste.  The fol-
lowing is his method of obtaining it:—
   Let 1Q0 parts of beryl, or emerald, be re.
duced  to  a fine powder, and fused in a sil-
ver crucible with 300 of pure potash.   Let
the mass be diffused in water, and dissol-
ved by adding muriatic  acid.   Evaporate
the solution, taking care to stir it toward
the end:  mix the residuum  with a large
quantity of water, and  filter, to separate
the silex.  Precipitate the filtered liquor,
which   contains the  muriates  of alumina
and  glucina,  with  carbonate  of  potash;
wash the  precipitate, and dissolve it in sul-
phuric  acid.  Add  a certain  quantity of
sulphate of potash, evaporate, and crystals
of alum will be obtained.  When no more
alum is afforded by adding sulphate of pot-
ash  and evaporating, add solution of car-
bonate  of ammonia in  excess, shake the
mixture well, and let it stand some hours,
till the glucina  is redissolved  by the ex-
cess of carbonate of ammonia, and nothing
but  the alumina remains at  the  bottom
of the vessel.   Filter the solution, evapo-
rate to dryness,  and expel the acid  from
the carbonate of glucina,  by slight ignition
in a crucible.  Tims 15 or 16 per cent of
pure glucina will be obtained.
   Glucina thus  obtained, is  a  white,  soft
powder, light, insipid, and adhering to the
tongue.   It does  not change vegetable 
GLU
GLU
blues.  It does not harden, shrink,  or ag-
glutinate  by  heat; and is infusible.  It is
insoluble  in  water, but forms  with it a
slightly ductile paste.  It is dissolved by
potash, soda, and carbonate of ammonia;
but not by pure ammonia.  It unites with
sulphuretted  hydrogen.  Its salts have a
saccharine taste,  with somewhat of astrin-
gency.
  * Sir H. Davy's researches have rendered
it  more than probable, that glucina is a
compound of oxygen and a peculiar metal-
lic substance, which may be  called gluci-
num.   By heating it along with potassium,
the latter was converted for the most part
into potash,  and dark  coloured particles,
having a  metallic  appearance, were found
diffused through the mass, which regained
the earthy character by being heated in the
air, and   by  the action of water.  In this
last case, hydrogen was slowly disengaged.
According to Sir H. Davy, the prime equi-
valent of glucina would be 3.6 on the oxy-
gen scale, and that of glucinum 2.6. These
are very nearly the equivalents of lime, and
calcium.   From  the composition  of the
sulphate, Berzelius infers the equivalent to
be 3.2, and that of its basis  2.2.»
  Glue.   An inspissated jelly made from
the parings  of hides and other offals, by
boiling them in water, straining  through
a wicker  basket,  suffering  the impurities
to subside,  and then boiling it a second
time.  The  articles should first be digest-
ed in lime-water, to cleanse them  from
grease and  dirt; then steeped in water,
stirring them well from time to time; and
lastly, laid in a heap,  to have the water
pressed  out, before they are put into the
boiler.  Some recommend, that the water
should be kept as nearly as possible to a
boiling heat, without suffering it to enter
into ebullition.  In this state  it is poured
into flat  frames or moulds, then  cut into
square pieces when congealed, and after-
ward  dried  in a  coarse net.  It is said to
improve  by  age;  and that glue is reckoned
the  best, which  swells considerably with-
out dissolving by three or  fdur days infu-
sion in cold  water, and recovers its former
dimensions and properties by drying.
   Shreds or  parings of vellum, parchment,
or  white leather, make a clear  and almost
colourless glue.
   Gluten (Vegetable). If wheat-flour
be  made into a  paste,  and washed in a
large quantity of water, it is separated in-
to  three distinct substances;  a mucilagi-
nous  saccharine  matter, which is readily
dissolved in the liquor, and may  be sepa-
rated  from it by evaporation; starch, which
is suspended in the fluid, and  subsides to
the  bottom  by repose; and gluten, which
remains in the hand, and is tenacious, very
ductile,  somewhat elastic, and of a brown-
gray colour. The first of  these  substan-
ces does not essentially differ from other
saccharine mucilages.  The second, name-
ly, the starch,  forms a gluey fluid by boil-
ing in water, though it is scarcely, if at alL
acted upon by that fluid when cold.   Its
habitudes and  products with the fire, or
with  nitric  acid,  are nearly the same as
those of gum and of sugar.  It appears to
be  as much more remote from the saline
state than gum, as  gum  is more remote
from that state than sugar.
   The vegetable gluten, though it existed
before  the  washing, in  the  pulverulent
form, and has acquired  its tenacity and ad-
hesive qualities from the  water it has im-
bibed, is nevertheless  totally insoluble in
this fluid. It has scarcely any taste. When
dry, it is semi-transparent, and resembles
glue in its colour and appearance.  If it be
drawn out thin, when first obtained, it may
be dried by exposure to the air; but if it
be exposed to warmth and moisture while
wet, it putrefies like an animal  substance.
The dried gluten applied to the flame of
a  candle, crackles,  swells, and burns ex-
actly like a feather, or piece of horn.  It
affords the same  products by  destructive
distillation as  animal matters  do; is  not
soluble in alcohol,  oils, or ether, and is
acted upon by acids and alkalis, when heat-
ed.  According to Rouelle, it is the same
with the caseous substance of milk.
   * Gluten of Wheat.—M.Taddey, an Italian
chemist,  has  lately ascertained that the
gluten of wheat may be decomposed  into
two principles, which he has distinguished
by the names, gliadine  (from yxia. gluten),
and zimome (from pv/u» ferment). They are
obtained in a separate  state by kneading
the  fresh gluten  in successive portions of
 alcohol, as long as that liquid continues to
 become milky,  when diluted with water.
 The  alcohol   solutions being  set  aside,
gradually deposite  a whitish matter, con-
sisting of small filaments of gluten, and be-
come perfectly transparent.    Being now
 left to slow  evaporation,  the gliadine re-
mains behind, of the consistence of honey,
and mixed with  a  little  yellow resinous
 matter, from which  it may be freed, by di-
gestion  in sulphuric ether, in  which glia-
dine is not sensibly soluble.  The portion
of the  gluten not dissolved by the alcohol
 is the zimome.
   Properties of Gliadine.—When dry,  it
 has a straw-yellow colour, slightly  trans-
 parent, and in thin plates, brittle, having a
 slight smell, similar to  that of honeycomb,
 and, when slightly heated, giving  out an
 odour similar to that of boiled apples.  In
 the mouth, it becomes  adhesive, and has a
 sweetish and balsamic taste.   It is pretty
 soluble  in boiling alcohol, which loses its
 transparency in proportion as it cools, and
 then retains only a small  quantity in solu-
 tion.  It forms  a kind of varnish in those 
GOL                                  GOL
bodies to which it is  applied.  It  softens,
but does not dissolve in cold distilled  wa-
ter.  At  a  boiling heat  it  is  converted
into froth, and the liquid  remains  slightly
milky.  It is specifically heavier than water.
   The  alcoholic solution of gliadine  be-
comes milky, when mixed with water, and
is precipitated in white flocks by the alka-
line carbonates.  It is scarcely affected by
the mineral and vegetable acids.  Dry glia-
dine  dissolves in caustic alkalis  and in
acids.  It swells upon red-hot coals, and
then contracts in the manner of animal sub-
stances.  It  burns with  a  pretty lively
flame, and leaves behind it a light spongy
charcoal, difficult to incinerate.  Gliadine,
in some respects, approaches the  proper-
ties of resins; but differs from them in be-
ing  insoluble  in sulphuric  ether.  It is
very sensibly  affected by the infusion of
nut-galls.  It is capable of itself of under-
going a slow  fermentation,  and produces
fermentation in saccharine substances.
   From the flour of barley, rye,  or oats, no
gluten  can be extracted, as from that of
wheat, probably because they contain too
small a  quantity.*   See Zimome.
   • Gneiss.   A  compound rock,  consist-
ing of feldspar, quartz, and mica, disposed
in slates, from the predominance of  the
mica scales.   Its  structure  is  called by
Werner, granular-slaty.  This  geognostic
formation is  always  stratified; contains
sometimes crystals  of schorl, tourmaline,
and garnet, and is  peculiarly rich in me-
tallic ores.*
   Gold is a yellow metal, of specific gra-
vity  19.3.  It  is soft, very tough, ductile,
and malleable; unalterable and fixed, whe-
ther exposed to the atmosphere, or to the
strongest heat of furnaces. Powerful burn-
ing mirrors have volatilized it;  and it has
been  driven up in  fumes, in the metallic
state, by flame urged upon  it by a stream
of oxygen gas.  The  electric shock  con-
verts it  into a purple oxide, as may be seen
by transmitting that  commotion through
gold  leaf, between  two plates of glass; or
by causing the explosive spark of three or
more square feet of coated glass, to  fall
upon a gilded surface.  A heat  of 32° W.
or perhaps 1300° F. is required  to melt it,
which does not happen till after ignition.
Its colour when melted, is of a bluish-green;
and the same  colour is exhibited, by light
transmitted through gold  leaf.
   The limits of the ductility and  mallea-
bility of gold are not  known.
   The method of extending gold used by
the gold-beaters, consists in hammering a
number of thin rolled plates between skins
or animal membranes. By the weight and
measure ofthe best wrought gold leaf, it is
found, that one grain  is made to cover 56f
square inches; and from the  specific gravi-
ty of the metal, together with this admea-
surement, it follows that the leaf itself is
5T*V?To" Part °f w inch thick.  This, how-
ever, is not the limit of the malleability of
gold; for the gold-beaters find it necessary
to add three grains of copper in the ounce
to harden the gold, which otherwise would
pass round the regularities of the newest
skins, and not over them; and in using the
old  skins,  which  are not  so perfect and
smooth, they proceed so far  as to add twelve
grains.  The wire  which  is  used  by  the
lacemakers, is  drawn from an ingot of sil-
ver, previously gilded.  In this way, from
the known diameter of the wire, or breadth
when  flattened, and its length, together
with the quantity of gold used, it is found,
by computation, that the covering of gold
is only one 12th  part of the thickness of
gold-leaf, though it is still  so perfect as to
exhibit no  cracks  when viewed  by a mi-
croscope.
  No acid acts readily upon gold but aqua
regia, and aqueous chlorine. Chromic acid
added  to  the  muriatic, enables it to dis-
solve gold.
  The  small degree of concentration, of
which aqueous  chlorine is susceptible, and
the  imperfect  action of the latter  acids,
render aqua regia  the most convenient sol-
vent for this metal.
  When gold is immersed in aqua  regia,
an effervescence takes  place;  the solution
tinges animal matters of a deep purple, and
corrodes them.  By careful evaporation,
fine crystals of a topaz colour are obtained.
The gold is precipitated from  its solvent,
by a great number of  substances.  Lime
and  magnesia precipitate it in  the form of
a yellowish  powder. Alkalis  exhibit the
same appearance;  but an excess of alkali
redissolves the precipitate.  The precipi-
tate  of gold obtained from aqua regia by
the addition of a  fixed alkali, appears to
be a true oxide, and is  soluble in the  sul-
phuric, nitric,  and  muriatic  acids; from
which, however, it separates by  standing,
or by  evaporation  of the  acids.   Gallic
acid pre<Slp!*|rtes gold of a  reddish colour,
very soluble in the nitric acid, to which it
communicates a fine blue colour.
  Ammonia precipitates  the  solution of
gold much more readily than fixed alkalis.
This precipitate, which  is of a brown, yel-
low, or orange  colour, possesses the pro-
perty of detonating with a  very considera-
ble noise when gently heated.  It is known
by the  name of fulminating gold.  The pre-
sence of ammonia  is necessary to give the
fulminating property to the precipitate of
gold; and it will be  produced  by precipi-
tating it with  fixed  alkali,  from an aqua
regia previously made by  adding sal  am-
moniac to nitric acid; or by  precipitating
the gold from pure aqua regia, by means
of sal ammoniac, instead of the  ammonia
alone.   The fulminating gold weighs one- 
GOL                                  GOL
fourth more than the gold made use of. A
considerable degree of precaution is ne-
cessary in  preparing  this substance.  It
ought not to be dried but in the open air,
at a distance from a fire, because  a  very
gentle heat may cause it to explode.   Se-
veral  fatal accidents  have arisen from its
explosion, in consequence of the friction
of ground  stoppers in bottles containing
this substance,  of which a small portion
remained in the neck.
  Fulminating gold, when exposed by Ber-
thollet to a  very gentle  heat in a  copper
tube, with the  pneumatical  apparatus of
mercury, was deprived of its fulminating
quality, and converted into an oxide, at the
same time that ammoniacal gas was disen-
gaged.  From this dangerous experiment .
is ascertained, that fulminating gold con-
sists of oxide of gold combined with am-
monia.  The  same  eminent philosopher
caused fulminating gold to explode in cop-
per vessels. Nitrogen gas was disengaged,
a few drops of water appeared, and the
gold  was reduced to the metallic form. In
this experiment he infers, that the  ammo-
nia  was  decomposed; that  the  nitrogen,
suddenly assuming the elastic state, caused
the explosion, while the oxygen of the ox-
ide united with the hydrogen of the alkali,
and formed the water.
   This satisfactory theory was still farther
confirmed by the  decomposition  of fulmi-
nating gold, which takes place in conse-
quence of the action of the concentrated
sulphuric acid,  of melted sulphur, fat oils,
and ether; all which deprived it of its fulmi-
nating quality, by combining with  its am-
monia.
   Sulphurets predpitate  gold from its sol-
vent, the alkali uniting with the acid, and
the gold falling down combined with the
sulphur; of which, however, it may be de-
prived by moderate heat.
   Most metallic substances precipitate gold
from aqua regia: lead, iron, and silver, pre-
cipitate it of a deep and dull purple colour;
copper and iron throw it down in  its me-
tallic state; bismuth, zinc,  and mercury,
likewise precipitate it.  A plate of tin, im-
mersed in a solution of gold, affords a pur-
ple powder, called the purple powder  of
Cassius, which is  used to paint in enamel.
   Ether, naphtha, and essential oils, take
gold from  its solvent, and  from liquors,
which have been called potable gold.  The
gold which is precipitated by evaporation
of these fluids, or by the addition of sul-
phate of iron to the solutionjof gold, is  of
the utmost  purity.
   Most metals unite  with gold  by fusion.
With silver it forms a compound, which is
paler in proportion to the quantity of  silver
added.  It  is remarkable, that  a  certain
proportion, for example, a fifth part, ren-
ders it greenish.  From this circumstance.
as well as from that of a considerable pro-
portion  of these  metals separating from
each other by  fusion,  in  consequence of
their different specific gravities, when their
proportions do  not greatly differ, it should
seem, that their union  is little  more than
a mere mixture without combination; for,
as gold leaf  transmits the green rays of
light, it will  easily follow, that particles
of silver, enveloped in particles of gold,
will reflect a green instead of a white light.
  A strong heat is  necessary to combine
platina with gold: it greatly alters the co-
lour of the gold, if its weight exceed the
forty-seventh part of the mass.
  Mercury is strongly disposed to  unite
with gold, in all proportions  with which it
forms an  amalgam: this, like other amal-
gams,  is  softer the larger the proportion
of mercury.  It softens and liquefies by
heat, and crystallizes by cooling.
  Lead unites with gold, and considerably
impairs its ductility; one-fourth of a grain
to an ounce rendering it  completely brit-
tle.  Copper  renders   gokl  less ductile,
harder, more fusible, and of a deeper co-
lour.   This is the  usual addition in coin,
Mid other articles  used  in  society.  Tin
renders it brittle in proportion  to its quan-
tity; but it is a common error of chemical
writers to say, that the slightest addition
is sufficient for this purpose.  When alloyed
with  tin, however,  it will not bear a red
:ieat.  With  iron it forms a gray mixture,
 which obeys the magnet. This metal is
very hard, and is said to be much superior
 .0 steel for the fabrication  of cutting in-
 struments.  Bismuth renders  gold white
 and brittle; as  do likewise nickel, manga-
 nese, arsenic, and antimony.  Zinc produces
 the same effect; and, when equal in weight
 to the gold, a metal of a fine grain  is pro-
 duced, which is said to be well adapted to
 form the  mirrors of reflecting telescopes,
 on account of the  fine polish it is suscep-
 tible of, and its not being subject to tarnish.
 The alloys of gold  with molybdena are not
 known.   It could not be mixed with tung-
 sten, on account of the infusibility  of this
 last substance. Mr. Hatchett gives  the fol-
 lowing order of different metals, arranged
 as they diminish the ductility of gold: bis-
 muth, lead, antimony, arsenic, zinc, cobalt,
 manganese, nickel, tin, iron, platina, cop-
 per, silver.  The  first three were nearly
 equal in effect; and the platina was not
 quite pure.
   For the purposes of coin  Mr. {Hatchett
 considers an alloy of equal parts of sUver
 and copper as  to be preferred, and  copper
 alone as preferable to  silver alone.
   * The peroxide of gold thrown down by
 potash, from a solution of the  neutral ran-
 riate, consists, according to  Berzelius, of
 100 gold, and 12 oxygen.  It is probably a
tritoxide.jfcThe protoxide of a greenish co- 
GRA                                GRA
lour, is procured by treating with potash-
water, muriate of gold, after heat has ex-
pelled the chlorine.   It seems to consist of
100 metal -+- 4 oxygen.  The prime equi-
valent of gold comes out apparently 25.*
  The gold coins of Great Britain contain
eleven parts of gold, and  one of copper.
See Assay, Gilding, and Ores of Gold.
  * Gorgonia Nobilis  The red coral.
It consists of an interior stem, composed
of gelatinous matter and carbonate of lime,
with a cortex, consisting of membrane with
carbonate of lime, coloured  by some un-
known substance *
  Goulard's Extract.  A saturated so-
lution of subacetate of lead.  See Lead.
  •Gouty  Concretions.   These  have
been called chalk-stones from their appear-
ance; but Dr. Wollaston first demonstrated
their true composition to be uric acid, com-
bined with ammonia,  and  thus explained
the mysterious pathological relation be-
tween gout and gravel.  See Concretion
(Urinary).
  Gouty concretions  are soft and friable.
They are insoluble in cold, but slightly  ir
boiling water.  An acid being added to this
solution, seizes the soda, and the uric acid
is deposited in small crystals.  These con-
cretions dissolve readily in  water of pot-
ash.  An artificial compound may be made
by triturating uric acid and soda with warm
water, which exactly resembles gouty con-
cretions, in its chemical constitution.*
  •Grainer.   The lixivium obtained by
infusing pigeons' dung in water, is  used
for giving flexibility to skins in the process
of tanning, and is called the grainer.*
  • Grammatite.  See Tremolite."
  •Granatite.  See Grenatite.*.
  •Granite.  A compound rock, consist-
ing of quartz, feldspar, and mica, each crys-
tallized and cohering  by  mutual affinity,
without any basis or cement. The feldspar
commonly predominates, and the mica  is
in smallest quantity.  The colours of the
feldspar are white, red, gray, and green.
The quartz is  light gray,  and  the  mica
dark.  The granular crystals vary exceed-
ingly in size, in different granite  rocks.
Occasionally granite is stratified; but some-
times no stratification  can  be perceived.
Large globular masses, called rolling stones,
are frequently met with, composed each  of
concentric lamellar  concretions.  Schorl,
garnet,  and tinstone are frequently present
in granite.  Tin and iron are the only me-
tals abundantly found in this rock. It con-
tains molybdena, silver, copper,  lead, bis-
muth, arsenic, titanium, tungsten, and co-
balt.  It is, however, poorer in ores than
many other rock formations.*
   Granulation; the method of dividing
metallic substances  into grains or small
particles, in order to facilitate their com-
bination with other substances, and some-
times for the purpose of readily subdivi-
ding them by weight.
  This is done either by pouring the melt-
ed metal into water, or by agitating it in a
box  until the moment of congelation, at
which instant it becomes converted  into a
powder.
  Various contrivances are used to prevent
danger, and insure success, in the seve-
ral manufactories that require granulation.
Copper is granulated for making brass, by
pouring it through a perforated ladle into
a covered vessel of water with a moveable
false bottom.   A compound metal, consist-
ing chiefly  of lead, is  poured  into water
through  a  perforated  vessel of another
kind, for making small-shot, in which the
height above the surface of the fluid re-
quires particular adjustment  In  a  new
manufactory of this kind, the height is up-
ward of 100 feet.
  •Graphite.  Rhomboidal graphite of
Jameson, or plumbago, of which he gives
two sub-species, the scaly and compact.
  1st, Scaly Graphite.  Colour dark steel-
gray, approaching to iron-black. It occurs
massive, disseminated  and crystallized.
The  primitive form is a rhomboid.  The
secondary form is the equiangular six-sided
table. Lustre splendent, metallic. Cleavage
single.  Fracture  scaly  foliated.   Streak
shining and metallic. Hardness sometimes
equal to that of gypsum.
  Perfectly sectile. Rather difficultly fran.
gible.  It writes and soils.  Streak on paper
black.  Feels very greasy.   6p. gr. from
1.9 to 2.4.
  2d,  Compact  Graphite.  Colour  rather
blacker than preceding.  Massive, disse-
minated and in columnar concretions.  In-
ternal  lustre glimmering  and metallic.
Fracture small  grained uneven, passing
into conchoidal.  When heated in a furnace,
it burns without flame  or  smoke, forming
carbonic acid, and leaving a residuum of
iron.   Its constituents are, carbon 91, iron
9.—Berthollet.  It sometimes contains nic-
kel, chromium, manganese, and oxide of
titanium.  It usually occurs  in beds, some-
times disseminated and in imbedded mas-
ses,  in granite,  gneiss, mica-slate, clay-
slate,  foliated granular  limestone,  coal
and trap formations.   It is found in gneiss
in Glen Strath Farrar in Inverness-shire;
in the  coal  formation near Cumnock in
Ayrshire, where it is imbedded in green-
stone, and in Columnar  glance-coal.  At
Borrodale  in Cumberland,   it  occurs  in
beds of very varying thickness, included
in a bed of trap, which is  subordinate to
clay-slate; and in many places on the con-
tinent,  and elsewhere.  The  finer kinds
are first boiled in oil, and then cut into ta-
bles for pencils.  Grates  are  blackened
with it, and crucibles formed of a mixture
of it and clay.—Jameson.* 
GRE                                GUA
  Gravity, a term used by physical wri-
ters to denote the cause, by  which all bo-
dies move toward each  other, unless pre-
vented by  some other  force or obstacle.
See Attraction.
  Gravity (Specific).  See Specific
Gravity.
  For the  specific gravities of different
kinds of elastic fluids, see the table at the
article Gas.
  * Graywacke.  A mountain formation,
consisting of two similar tocks,  which al-
ternate with, and pass into each other, cal-
led graywacke, and graywacke-slate. The
first possesses the characters ofthe forma-
tion.   It is a rock composed of pieces  of
quartz, flinty-slate, feldspar, and clay-slate,
cemented  by a  clay-slate  basis.  These
pieces vary in size from a hen's  efrg to lit-
tle grains.   When the texture becomes ex-
ceedingly fine grained, the rock constitutes
graywacke-slate.  Its colour is usually ash
or  smoke-gray, without the yellowish-gray,
or  greenish tinge, frequent  in primitive
slate.  It has not the continuous lustre of
primitive slate, but glimmers from inter-
 spersed scales of mica. It contains quartz
 veins, but no beds of quartz. Petrifactions
 are found in it.  These rocks are stratified,
 forming, when alone, round-backed hills,
 with deep valleys between them. Immense
 beds  of trap, flinty-slate,  and transition
 limestone,  are contained in this formation;
 as well as numerous metallic ores  in beds
 and large veins.*
    * Greek Fire. Asphaltum is supposed
 to have been its  chief constituent, along
 with nitre and sulphur.*
    »  Green-earth.  Colour  celandine-
 green, and green of  darker shades.  Mas-
 sive, and  in globular and amygdaloidal
 shaped pieces,  sometimes hollow, or  as
 encrusting  agate balls.  Dull.  Fracture
 earthv.  Opaque.  Feebly glistening in the
 streak.  Soft and sectile.  Rather greasy.
 Adheres slightly to the tongue.  Sp. gr.
 •2.6.  Before the  blow-pipe, it is converted
 into a black vesicular slag.  Its  constitu-
 ents are silica, 53, oxide of iron  28, mag-
 nesia 2, potash 10, water 6. It is a frequent
 mineral in the  amygdaloid of Scotland,
 England, Ireland, Iceland, and the Faroe
 Islands. It occurs in Saxony, near Verona,
 the Tyrol, and Hungary.   It is the moun-
 tain-green of artists in water colours.   Its
 colour is durable, but not so bright as that
 from copper. The green-earth of Verona,
 of which the analysis is given above, is
 most esteemed.—Jameson.*
    •Greenstone.   A  rock ofthe trap
 formation,  consisting of hornblende  and
 feldspar, both in the  state of grains, or
  small crystals.  The hornblende is common-
  ly most  abundant,  and  communicates a
  preen tinge to the feldspar.*
  b Vol.  II.
  • Grenatite, or prismatic garnet. See
Staurotide.*
  * Guaiacum.  A resinous-looking sub-
stance,  extracted  from the  very dense
wood of a tree growing in the West In-
dies, calle'd guaiacum officinale.
  It differs however from resins in its  ha-
bitudes with nitric acid, as  Mr. Hatchett
first showed.  Its sp. gr. is 1.229.  Its co-
lour  is yellowish-brown,  but it becomes
green on exposure to light.  It is transpa-
rent and breaks with a resinous fracture.
Its odour is not disagreeable, but when  a
very little of its powder,  mixed  with  wa-
ter, is swallowed, it excites a very unplea-
sant burning sensation  in  the fauces  and
stomach.  Heat fuses it, with the  exhala-
tion of a somewhat fragrant smell.
   Water dissolves a certain portion of it,
acquiring a brownish tinge,  and  sweetish
taste.  The soluble matter is left when the
water is evaporated. It constitutes 9 per
cent  of the whole, and  resembles  what
some chemists call extractive.
   Guaiacum is  very soluble in  alcohol.
This solution, which is brown coloured, is
decomposed by water.  Aqueous chlorine
throws down a pale blue  precipitate from
 it.
   Guaiacum  dissolves readily in alkaline
 leys, and in sulphuric acid; and in the ni-
 tric with effervescence.  From the solu-
 tion in the last liquid, oxalic acid may  be
 procured by evaporation, but no artificial
 tannin can be obtained, as from the action
 of nitric acid on the other resins.
  Guaiacum distilled in close vessels, leaves
 30.5  per  cent of charcoal, being nearly
 double the quantity from an equal weight
 of the common resins.  From Dr. Wollas-
 ton's experiments,  it woulel appear that
 both air and  light are  necessary to pro-
 duce the change in guaiacum from yellow
 to green.  And Mr. Brande found that this
 green colour was more rapidly brought on
 in oxygen, than in common air.  With  ni-
 tric acid, or chlorine, it becomes green,
 next blue, and lastly brown.*
    Formerly guaiacum was much commend-
 ed in syphilis and other complaints; at pre-
 sent it is used chiefly in  rheumatism, dis-
  solved in liquid ammonia.
    Guano.  A substance found on many of
 the small islands in the South Sea,  which
  are the resort of numerous flocks of birds,
  particularly of the ardea and  phxnicopte-
  ros  genus.  It is dug from beds 50 or 60
  feet thick, and used as  a valuble manure
  in Peru, chiefly for Indian corn.  It is of a
  dirty yellow colour, nearly  insipid to  the
  taste, but has a powerful smell partaking
  of rastor and valerian.   According to  the
  analyses of Fourcroy and Vauquelin, about
  one-fourth of it is uric acid partly satura-
  ted with  ammonia and  lime.   It contains
                        13 
GUN                                GYP
 likewise oxalic acid, partly saturated with
 ammonia and potash; phosphoric acid com-
 bined with the same bases and with lime;
 small quantities of sulphate  and muriate
 of potash, and ammonia; a small portion
 of fat matter; and sand, partly quartzose,
 partly ferruginous.
   Gum.  The mucilage of vegetables. The
 principal gums are, 1. The common gums,
 obtained fiom the plum, the  peach, the
 cherry tree,  &c.—2. Gum Arabic,  which
 flows naturally from the acacia in Egypt,
 Arabia, and elsewhere.  This  forms a dear
 transparent mucilage with water.—3. Gum
 Seneca, or  Senegal.  It does not greatly
 differ from  gum Arabic: the  pieces are
 larger and clearer; and it  seems to  com-
 municate a higher degree of  the adhesive
 quality to water.   It is much used by ca-
 lico-printers and others.  The first sort of
 gums are frequently sold by this name, but
 may be  known by their darker  colour.—4.
 Gum Adragant or Tragacanth.  It  is ob-
 tained from a small plant of the same name
 growing in Syria, and other eastern  parts.
 It comes to  us in small white  contorted
 pieces resembling worms. It  is usually
 dearer than  other  gums, and forms  a
 thicker jelly with water.
   Mr. Willis has found, that the root of the
 eommon blue-bell, hyacinthus  non  scrip-
tus, dried and powdered, affords a  muci-
lage, possessing all  the qualities of that
from gum Arabic. Lord Dundonald has ex-
tracted a mucilage also from  lichens.
   Gums treated with nitric acid afford the
acid of sugar.
   Gum (Elastic).  See Caoutchouc.
   Gum-Resin.  The principal gum-resins
are  frankincense,  scammony,  asafcetida,
aloes, gum ammoniac, and gamboge.
   Gunpowder.  This well known powder
is composed of 75 parts, by weight, of ni-
tre, 16 of charcoal, and 9 of sulphur, inti-
mately blended together by long pounding
in wooden mortars, with a small quantity
of water. This proportion of the  mate-
rials is the most effectual.   But the  varia-
tions  of strength  in  different samples  of
gunpowder are generally occasioned by
the more or less intimate  division and
mixture of the parts.   The reason of this
may be easily deduced from  the conside-
ration, that nitre  does  not detonate until
in contact with inflammable matter; whence
the whole detonation will be more 6peedy,
the more numerous the surfaces of con-
tact.  The same cause  demands, that the
ingredients should be very pure, because
the mixture of foreign  matter not only di-
minishes the quantity of  effective  ingre-
dients which it represents, but  likewise pre-
 vents the contacts by its interposition.
   The nitre of the third boiling is usually
 chosen  for making  gunpowder, and the
 charcoal  of light woods is  preferred  to
 that of those which are heavier, most pro-
 bably because this last,  being harder,  is
 less pulverable.
   The requisite pounding ofthe materials
 is performed in the large way by a mill, in
 which wooden  mortars  are disposed  in
 rows,  and in each of which a pestle  is
 moved by the arbor of a  water-wheel; it is
 necessary  to  moisten the  mixture from
 time to time with water, which  serves  to
 prevent its being dissipated in the  pulve-
 rulent form,  and  likewise  obviates the
 danger of explosion from the  heat  occa-
 sioned by the blows. Twelve hours' pound-
 ing is in general required to complete the
 mixture; and when this is done, the gun-
 powder is in fact made, and only requires
 to be dried to render it fit for use.
   The granulation of gunpowder is per-
 formed by placing the mass,  while  in the
 form of a stiff paste,  in a wire sieve, co-
 vering it with a board, and agitating the
 whole; by this means  it is  cut into  small
 grains or parts, which, when of a requisite
 dryness, may be rendered smooth or glossy,
 by rolling them in a cylindrical vessel or
 cask.  Gunpowder in this form takes fire
 more speedily than if it  be  afterward re-
 duced to powder, as may  be easily ac-
 counted for from  the circumstance, that
 the inflammation is more speedily propa-
 gated through the interstices of the grains.
 But the process of granulation does  itself,
 in all probability, weaken the gunpowder,
 in the same manner as it is weakend by
 suffering it to  become damp; for in this
 last case, the nitre, which is the only solu-
 ble ingredient,  suffers a partial solution in
 the water, and a separation  in crystals of
 greater or less magnitude; and accordingly
 the surfaces of contact are rendered less
 numerous.
  Berthollet found, that the elastic pro-
 duct, afforded  by the detonation of gun-
 powder,  consisted of two  parts  nitrogen
gas, and one, carbonic acid gas. The sud-
den extrication and expansion of these airs
 are the cause ofthe effects of gunpowder.
  * Gypsum.   This genus contains 2 spe-
cies, by Professor Jameson; the prismatic,
and the axifrangible.
  I.—Prismatic gypsum or anhydrite.  Mu.
riacit.—Werner.  Of this there are 5 sub-
species.
  1.  Sparry anhydrite.  See Cube-svKv..
  2.  Scaly anhydrite.  Colour white  of va-
rious shades passing into  smalt-blue.  Mas-
sive, and in  granular  concretions. Lustre
splendent, pearly.  Cleavage imperfect and
curved. Translucent on the edges.  Easily
broken.  Sp. gr. 2.96. Its constituents are,
lime 41.75, sulphuric acid 55, mur. of soda
 1.0.  It is found in the salt mines of the
Tyrol, 5088 feet above the level of the sea. 
GYP                                  GYP
   3. Fibrous anhydrite.   Colours, red, blue,
 and gray.  Massive, and in coarse fibrous
 concretions. Lustre, glimmeringandpearly.
 Translucent on the edges.   Rather easily
 frangible.  Spec. grav. 3.  It is found in the
 salt mines on  the continent.  The blue is
 sometimes cut into ornaments.
   4. Convoluted  anhydrite.  Colour,  dark
 milk-white.  Massive, and in  distinct con-
 cretions.  Lustre, glimmering and pearly.
 Fracture fine splintery. Translucent on the
 edges.  Sp. gr. 2.85.   Its constituents are,
 42 lime, 56.5  sulphuric acid, 0.25 muriate
 of soda. It occurs in the salt mines of Boch-
 nia,  and at Wieliczka in Poland.  It has
 been calledpierre de tripes, from  its convo-
 luted concretions.
   5. Compact anhydrite. Colour gray, some-
 times with spotted delineations.   Massive,
 and in distinct granular concretions.   Fee-
 bly glimmering.  Fracture small splintery.
 Translucent.  Hardness and constituents as
 in the preceding.  Sp. gr. 2.95.
   II.—Axifrangible gypsum.
   This species contains, according to  Pro-
 fessor Jameson, 6 sub-species; sparry gyp-
 sum, foliated,  compact, fibrous, scaly foli-
 ated, and earthy  gypsum.
   1.  Sparry gypsum  or selenite.   Colours)
 gray, white,  and yellow, with occasional
 iridescence.  Massive,  disseminated, and
 crystallized. Its primitive form is an oblique
 four-sided  prism, with angles of 113° 8'
 and 66° 52'.   The following are  some of
 the  secondary  forms:  1. Six-sided prism,
 generally broad,  and oblique angular,  and
 four smaller lateral planes.  2. Lens.  3.
 Twin crystals, formed either by two lenses,
 or by two  six-sided prisms, pushed  into
 each other in the direction of their breadth.
 4. Quadruple crystal,  from  two twin crys-
 tals  pushed into each other in the direction
 of their length.   Lustre splendent, pearly.
 Cleavage threefold. Fragments rhomboidal.
 Semi-transparent, and transparent.  Refracts
 double.  Yields to the nail.  Scratches talc,
 but  not calcareous spar.  Sectile.  Easily
 frangible.   In  thin pieces flexible, but ine-
 lastic.  Sp. gr.  2.3.  It exfoliates and melts
 into a white enamel, which falls into a white
 powder.  Its constituents are, 33.9  lime,
 43.9 sulphuric acid, 21 water, and  2.1 loss;
 Bucholz.  It occurs principally in the floetz
 gypsum formation in thin layers;  less  fre-
 quently in rock salt; frequently in  the Lon-
 don blue clay.   Crystals are  daily  forming
 in  gypsum  hills,  and  in old mines.   It is
found in blue  clay, at  Shotover-hill, near
Oxford;  Newhaven, Sussex;  around Paris,
and all over the continent.  It  was used in
ancient times for window-glass.  Hence it
was called glacies maris, and lapis specu-
laris.
  2. Foliated granular  gypsum.  Colours,
 white, gray, and red; sometimes in spotted
 or  striped delineations.  Massive, and  in
 distinct concretions, or crystallized in small
 conical lenses.  Lustre, glistening, pearly.
 Cleavage as selenite.  Translucent.   Very
 soft, sectile, and easily frangible.  Sp. gr.
 2.3. Its constituents are, 32 lime, 30 sulphu-
 ric acid,  and  38 water, according to  Kir-
 wan.   It occurs in beds in primitive rocks,
 as gneiss and mica-slate; in transition clay-
 slate;  but most abundantly in beds in the
 rocks ofthe floetz class.   It is there asso-
 ciated  with   selenite,  compact   gypsum,
 fibrous gypsum,  rocksalt, stinkstone, and
 limestone.  It is  found  in Cheshire  and
 Derbyshire, at Luneburg, and other  places
 on the continent.  The foliated and com-
 pact gypsum, when pure and capable of re-
 ceiving a good polish, are termed alabaster
 by artists, who  fashion them  into statues
 and vases.  The coarser kinds are used  in
 small quantities in agriculture; and are con-
 verted by calcination into stucco.
   3. Compact  gypsum.  Colours,  white  of
 various shades, gray, blue, red, and yellow.
 Massive.   Dull.  Fracture  fine splintery.
 Translucent on the edges.  Soft, sectile,
 and easily frangible.  Sp. gr. 2.2.  Its  con-
 stituents are, 34 lime, 48 sulphuric acid, 18
 water.—Gerhard.  It occurs in beds, along
 with granular gypsum,  &c. It is  found  in
 the Campsie hills; in Derbyshire; at Ferry-
 bridge, Yorkshire, and in various places on
 the continent.
   4. Fibrous gypsum.  Colours, white, gray,
 and red.   Massive  and dentiform, and  in
 fibrous elistinct concretions.  Lustre, glis-
 tening and pearly.   Translucent. Soft,  sec-
 tile, and easily frangible.   lis  constituents
 are, 33. lime, 44.13  sulphuric acid, 21 wa-
 ter.  It occurs along with the other sub-
 species,  in red  sandstone near Moffat; in
 the Forth river  near Belfast;  in  Cumber-
 land, Yorkshire, Cheshire,  &c.  When cut
 en cabachon, and polished, it reflects a light,
 not unlike that of the cat's eye, and is  some-
 times sold as that stone.
   5. Scaly foliated gypsum.  Colour white.
 Massive, disseminated, and in distinct con-
 cretions.   Lustre,  glistening and  pearly.
 Fracture small scaly foliated.  Opaque, or
 translucent on the  edges.  Soft,  passing
 into friable. Sectile and easily frangible.
 It occurs along with selenite, at Montmar-
 tre near Paris,  in the third floetz formation
 of Werner.
   6. Earthy gypsum.   Colour   yellowish-
 white.  Composed of fine  scaly or dusty
 particles.  Feebly glimmering.  Feels mea-
 gre or rather fine.   Soils slightly.  Light.
 It  is found immediately  under the soil in
 beds several feet thick, resting on gypsum,
 in  Saxony, Switzerland,  and  Norway.—
Jameson* 
HKA
HKA
II.
H
      .KMATITES.   An ore of iron.*
        Hair.   From numerous  experi-
ments M. Vauquelin infers, that black hair
is  formed  of nine  different  substances,
namely;
  1. An animal  matter,  which constitutes
the greater part. 2. A white concrete oil in
small quantity.  3.  Another oil of a grayish-
green colour, more  abundant than the for-
mer.  4. Iron,  the  state of which  in the
hair is  uncertain.   5. A few particles of
oxide of manganese.  6. Phosphate of lime.
7.  Carbonate of lime, in  very small quanti-
ty.   8.  Silex, in a conspicuous quantity. 9.
Lastly, a considerable quantity of  sulphur.
  The  same experiments  show, that  red
hair differs from black, only in containing
a red oil instead of a blackish-green oil,
and that white hair differs from both these,
only in  the oil being nearly colourless, and
in containing phosphate of magnesia, which
is  not found in them.
  • Haumotome.  Cross-stone.*
  * Hartshorn, (Spirit of).  See  Am-
monia.*
  * Hauyne.   Colour  blue  of  various
shades.  It occurs imbedded in grains, and
rarely crystallized; in acute oblique double
four-sided pyramids, variously truncated.
Externally it is generally smooth, and edges
rounded.  Lustre splendent, to glistening,
and vitreous.  Cleavage quintuple. Frac-
ture  imperfect conchoidal.  Transparent
anel translucent.  Harder than apatite, but
softer than feldspar. Brittle.  Easily  fran-
gible.  Sp. gr. 2.7   It melts with  difficulty
before  the blow-pipe,  into a white nearly
opaque  vesicular   bead.  With  borax  it
melts into a  transparent wine-yellow glass.
With acids, it forms a transparent jelly. Its
constituents are, silica 30, alumina 15, lime
13.5, sulphuric acid 12, potash 11, iron  1,
loss  17.5.— Vauquelin; but by Gmelin, we
have silica 55.48, alumina 18.87, lime 11.79,
sulphuric acid  12.6, potash 15.45, iron 1.16,
loss  3.45.  It occurs imbeelded in the basalt
 rocks of Albano and Frescati.   Professor
 Jameson thinks it nearly allied  to azure-
 stone.*
   * Heavy Spar.  Baryte.  This genus
 is divideel by Professor Jameson into 4 spe-
 cies; rhomboidal, prismatic,  di-prismatic,
 and  axifrangible.
    1. Rhomboidal baryte, or  JVitherite.  Co-
 lours, white, gray, und yellow.  Massive.
 Disseminated,  in various imitative shapes,
 and crystallized.  The primitive form is a
 rhomboid of 8b° 6' and 91° 54'.   The se-
 condary forms are, the equiangular six.
 sided prism, truncated, or acutely acumi-
 nated, and  the acute double six-sided py-
 ramid. Prisms scopiformly grouped, or -m
druses.  Lustre glistening, and resinous.
Cleavage three-fold.   Principal  fracture
uneven.  Translucent.  Harder than  cal-
careous  spar.  Easily  frangible.   Sp. gr.
4.3.   Before the  blow-pipe it decrepitates
slightlv, and melts readily into a white ena-
mel;  soluble  with effervescence  in dilute
nitric acid.   It is carbonate of barytes, with
occasionally 1 per cent of carbonate of stron-
tites and sulphate of barytes.   It occurs in
Cumberland and Durham, in lead veins that
traverse a secondary limestone, which rests
on red  sandstone.  It is  an active poison,
and is employed for killing rats.
   2. Prismatic baryte,  or Heavy spar.  Of
this there are 9 sun-species; earthy, com-
pact, granular, curved lamellar, straight
lamellar, fibrous,  radiated, columnar, and
prismatic.  They  are all sulphates of ba-
rytes in  composition.  On account of its
forms of crystallization, we shall describe
the fresh straight lamellar heavy spar.
   Its colours are white, gray, blue, green,
yellow,  red, and brown.   Massive, in dis-
"tinct concretions, and crystallized. The
primitive  form is an  oblique, four-sided
prism of 101° 55'.  The  following are the
secondary  forms:  the  rectangular four-
sided table; the oblique four-sided table,
perfect or variously truncated or bevelled;
the longish six-sided table, perfect or be-
velled; the eight-sided  table,  perfect or be-
 velled.  Lustre splenelent, between resin-
 ous and pearly.  Cleavage, parallel  with
 the planes of the primitive prism.  Frag-
 ments  rhomboidal  and tabular.  Translu-
 cent or transparent, and refracts double.
 Scratches calcareous spar, but is scratch-
 ed by fluor spar.  Brittle.  Sp. gr. 4.1  to
 4 6. It decrepitates briskly before the blow-
 pipe, and then  melts into a white enamel.
 It phosphoresces on glowing coals with a
 yellow light. It is sulphate of barytes, with
 0.85 sulphate of strontites, and 80 oxide of
 iron.   It is found  almost always in veins,
 which occur in granite, gneiss, mica-slate,
 and other rocks.   The flesh-red  variety is
 often accompanied with  valuable ores.  In
 Great  Britain,  it occurs in veins of diffe-
 rent primitive and transition rocks, and in
 secondary limestone, &c. in the lead mines
 of Cumberland,  Durham, and Westmore-
 land.
    3. Di-prismatic baryte, or Strontianite.—
 Colour, pale asparagus-green, yellowish-
 white, and greenish-gray.  Massive, in dis-
 tinct concretions,  and crystallized. The
 primitive  form  is an oblique four-sided
 prism, bevelled on the extremities. Secon-
 dary figures are,  the  acicular six-sided
 prism, and the acicular  acute double six-
 sided pyramid. Lustre glistening or pearly. 
                 HEL

Cleavage, in  the direction of the lateral
planes of the  primitive form.   Fracture
tine grained uneven. Translucent. Harder
than calcareous spar, but softer than fluor.
Brittle.  Sp.  gr. 3.7.  Infusible before the
blow-pipe, but becomes white and opaque,
tinging the flame of a dark purple colour.
It is soluble  with effervescence  in dilute
nitric or muriatic acid; and paper dipped
in the solutions thus produced, burns with
a purple flame.  Its constituents are,
Strontian,     61.21  69.5  62.0    74.0
Carbonic acid, 30.20  30.0  30.0    25.0
Water,         8.50   0.5   8.0     0.5
              100.0 100.0  100.0  100.0
              Hope. Klapr. Pelle. Bucholz.
  It  occurs at Strontian  in Argillshire,
in veins that traverse gneiss,  along with
galena, heavy spar, and calcareous  spar.
" The peculiar earth which  characterizes
this mineral, was discovered by Dr. Hope,
and its various properties were made known
to the public in his excellent Memoir on
Strontites, inserted in the Transactions of
the Royal Society  of Edinburgh,  for the
year  1790.'—Jameson, vol.  ii.  whose ac-
count of the preceding species is a model
of mineralogical description.
  4. Axifrangible baryte, or  Celestine.—Of
this there  are five sub-species; foliated, pris-
matic, fibrous, radiated, and fine granular.
We shall  describe the foliated, and  refer to
Professor Jameson's work for the rest.
  Colours white, gray, blue, and flesh-red.
Massive, in lamellar concretions, and crys-
tallized; in the rectangular four-sided ta-
ble, in which the terminal planes  are be-
velled,  and in the  rectangular four-sided
table, bevelled on the terminal edges. Lus-
tre splendent, pearly.  Cleavage threefold.
Fracture  uneven;   fragments rhomboidal.
Translucent.   Scratches calcareous  spar,
but is scratched by fluor spar. Sectile, and
easily frangible.  Sp. gr. 3.9.  It melts be-
fore the blow-pipe into a white friable ena-
mel,  without  very sensibly  tinging the
flame.  It is sulphate of strontites, with
about 2 per cent of sulphate of barytes. It
occurs in  traptuff, in the Calton-hill at Ed-
inburgh, and in red sandstone at Inverness.
It is abundant in the neighbourhood of Bris-
tol.—Jameson*
  Heat.   See Caloric
  * Heliotrope.  A sub-species of rhom-
boidal quartz.  Colour, green of  various
shades.  The blood  and scarlet-red, and
the ochre-yellow dots and spots, are owing
to disseminated jasper.  Massive, and in
angular and rolled pieces.  Lustre  glisten-
ing, resinous. Fracture conchoidal. Trans-
lucent on the edges.   Easily frangible.
Hard, but softer than calcedony.   Rather
heavy.  Sp. gr. 2.63.  It is infusible before
the blow-pipe.  Its constituents are,  silica
84, alu mina 7.5, and iron 5.  It is found in
               HEP

rocks belonging to the secondary trap for-
mation. The finest heliotrope comes from
Bucharia and Siberia.  A variety is found
in the island of Rume in  Scotland.  It  is
cut into seals and snuff-boxes.  The Sibe-
rian wants the red spots.—Jameson*
  Heliotropium.  Turnsole. See Ar-
chil.
  * Hellebore.  The root of a plant for-
merly  used in  medicine, but now  nearly
discarded from practice, in consequence  of
the violence of its operation.  Vauquelin
ascribes  its acrimony to a  peculiar oil,
which  he separated from the infusion  in
alcohol, by distilling off the  latter.  It  is
very poisonous.  Orfila says, on the con-
trary, that  the  poisonous quality of helle-
bore root resieles  in  a principle soluble  in
water; and the powdered root is more cer-
tainly fatal, when* applied to a wound, than
when swallowed;  that the white hellebore
is more active than the black; and that the
alkaline extract, which forms a part ofthe
tonic pills of Bacher, is also very powerful.
Vomiting is the only antidote.*
  •Helvine.  A sub-species  of dodeca-
hedral garnet.  Colour wax-yellow.  Dis-
seminated,  in small  granular concretions,
and crystallized   in  small   tetrahedrons.
Glimmering,  or shining.   Fracture, small
grained, uneven.  Crystals, strongly trans-
lucent.  Softer than  quartz, but  harder
than feldspar.   Brittle.  Sp. gr. 32 lo 3.3.
It melts easily into a blackish-brown glass.
It occurs along  with slate-spar,   brown
blende, and fluor spar, in beds subordi-
nate to gneiss, near Schwartzenberg  in
Saxony.*
  * Hematin. The colouring principle  of
logwood, the hematoxylon campechianum  of
botanists.
  On the watery  extract  of  logwood, di-
gest alcohol for a day, filter  the solution,
evaporate,  add a  little water,  evaporate
gently again, and then leave  the liquid  at
rest.  Hematin is deposited in  small crys-
tals,  which after washing  with alcohol,
are brilliant, and of a reddish-white colour.
Their taste is bitter, acrid, and slightly as-
tringent
  Hematin forms  an orange-red solution
with boiling water, becoming yellow as it
cools, but recovering with increase of heat,
its former hue.  Excess of alkali converts
it first to purple, then to violet, and lastly,
to brown: in which state the hematin seems
to be decomposed.   Metallic oxides unite
with  hematin,  forming  a  blue-coloured
compound.   Gelatin  throws down reddish
flocculi.  Peroxide of tin, and acid, merely
redden it.*
  * Hepar Sulphuris.  A name anciently
given to alkaline  and earthy sulphurets,
from their liver-brown colour.*
  * Hepatic Ain.   Sulphuretted  hydro-
gen gas.* 
HOR
HOJt
   * Hepatite. Fetid, straight,  lamellar,
 heavy spar.  A variety of lamellar barytes,
 containing a minute portion of sulphur; in
 consequence of which, when it is  heated
 or rubbed, it  emits a  fetid sulphurous
 odour.*
   • Highgate Resin.  See Fossil Co-
 *AL.*
   • Hollow Spar.  Chiastolite.*
   * Holmite.  A new mineral, which oc-
 curs crystallized in the form of an oblique
 four-sided prism, and having a sp. gravity
 of 3.597.   Its constituents  are 27 lime,  21
 carbonic acid, 6$ alumina, 6$ silica, 29 ox-
 ide of iron, and 10 water.*
   • Hone.   The whet-slate of  mineralo-
 gists.*
   * Honey. It is supposed to consist  of
 sugar, mucilage, and an acid.*
   * Honey-Stone.  Mellite.  Crystal-
 lized Harz of Mohs; the pyramidal honey-
 stone of  Jameson.   Colour honey-yellow.
 Rarely massive, but very distinctly crystal-
 lized.  The primitive form  is a pyramid of
 118°  4' and 93° 22'.  The following are
 some of the secondary figures:  1st, The
 primitive  pyramid, truncated on  the api-
 ces, or on the apices and angles; 2d, These
 truncations  giving rise to a low rectangu-
 lar four-sided  prism,  or to an  irregular
 rhomboidal dodecahedron;  3d, The angles
 in the common  base flatly bevelled. Lustre
 splendent. Cleavage pyramidal.  Fracture
 conchoidal.   Semi-transparent.    Refracts
double.  Harder than gypsum, but not so
hard as calcareous spar.  Brittle.  Sp. gr.
 1.56.   Before the blow-pipe it   becomes
white and opaque, with black spots,  and is
at length reduced to ashes.  Heated in a
glass tube, it  becomes  black.   Friction
makes it slightly resino-electric.  Its con-
 stituents are, 16 alumina, 46 mellitic acid,
and 38 water.
  It occurs superimposed on bituminous
wood and earth-coal, and is usually accom-
panied with sulphur, at Artern in Thurin-
gia. See the sequel of amber, for the cri-
teria between it and mellite.*
  * Homberg's  Pyrophorus.   Ignited
 muriate of lime.*
  * Hoofs of Animals.  Coagulated al-
 bumen, like horn.*
  * Horn.  An animal substance, chiefly
 membranous, composed of coagulated al-
 bumen, with a little gelatin, and about half
 a per cent of phosphate of lime.  But the
 horns of the buck and hart  are of a  diffe-
 rent nature, being  intermediate  between
 bone and horn.*
  * Horn Silver.   Chloride of  Silver.*
  * Hornblende.    A  sub-species   of
 straight-edged  augite.   There are  three
 varieties of hornblende; the common, horn-
 blende-slate, and basaltic hornblende.
  1. Common hornblende.  Colour, greenish-
black, and black of other shades.  Massive,
 disseminated and, crystallized, in a broad,
 thin, very oblique, four-sided prism, and
 in a six-sided prism.  The lateral planes of
 the prism are deeply longitudinally streak-
 ed.  Lustre shining, pearly.  Cleavage two-
 fold and  oblique angular.  Fracture une-
 ven.  The black hornblende is opaque, the
 green translucent on the eelges.   Harder
 than apatite, but not so hard as feldspar.
 Mountain-green  streak.  When  breathed
 on, it yields a  peculiar smell.  Difficultly
 frangible.  Sp. gr.  3.25.  It melts before
 the blow-pipe,  with violent  ebullition into
 a grayish-black coloured glass.  Its consti-
 ents are, 42 silica, 12 alumina, 11 lime, 2.25
 magnesia,  30 oxide of  iron, 0.25 ferrugi-
 nous manganese, and 0.75  water,  with a
 trace of potash.  It is  an essential ingre-
 dient of the mountain  rocks, syenite and
 greenstone, and it occurs frequently in gra-
 nite, gneiss, &c.  It is found abundantly in
 the British Islands, and  on the Continent.
  2. Hornblende-slate.  Colour intermediate
 between greenish-black and blackish-green.
 Massive. Lustre glistening or pearly. Frac-
 ture  straight   slaty.  Fragments tabular.
 Opaque. Streak greenish. Semi-hard. Dif-
 ficultly frangible.  It occurs in beds in
 gneiss, in Aberdeenshire, Banffshire, and
 Argyllshire, in  many parts of England and
Ireland, and abundantly on the Continent.
  3. Basaltic Hornblende.  Colour,  velvet-
black, or brownish-black. It occurs crys-
tallized, in the following figures:—an un-
equiangular six-sided prism, and the six-
sided  prism, both  variously  acuminated.
Lustre of the cleavage, which is double, is
 splendent, approaching to pearly.  Fracture
 small  grained  uneven.   Opaque.   Rather
 harder than common hornblende, and more
 easily frangible. Streak dark  grayish-white.
 Sp. gr. 3.16.  It fuses into  a  black glass.
 Its constituents are, 47  silica, 26 alumina,
 8 lime, 2 magnesia, 15  oxide of  iron, and
 0.5 water.  It occurs  imbedded  in  basalt,
 along with olivine and augite, at Arthur's
 Seat, near Edinburgh, in Fifeshire, and the
 Islands of Mull, Canna, Eigg, and Skye.
 In the basaltic  rocks of England, Ireland,
 and the Continent.—Jameson.*
  *  Hornstone.   Professor Jameson's
ninth sub-species of rhomboidal quartz.
 He  divides it into splintery hornstone, con-
 choidal hornstone, and woodstone.
  1. Splintery hornstone.  Colours gray, red,
 and green.  Massive, in balls, lenticular,
 and  in six-sided  prismatic  supposititious
 crystals.  Dull.  Fracture  splintery, and
 somewhat like  horn in appearance, whence
 the name.   Translucent on the  edges.
 Less hard than  quartz or flint.  Difficultly
 frangible.  Sp.  gr.  2.6.  Infusible  before
 the blow-pipe.  Its constituents are, 98.25
 silica, 0.75 alumina,  0.50  oxide of iron,
 0.50 water.  It occurs in veins  in  primi- 
HYA
HYD
tive countries, along with ores of silver,
lead, zinc, copper, and iron, and forming
the  basis  of hornstone porphyry.   It is
found in  Arran, Perthshire,  Argyllshire,
and many other counties of Scotland, and
abundantly on the  Continent.  Hornstone
porphyry at Efsdale in Sweden, is cut into
vases, candlesticks, &c. and  the  pedestal
of the statue of Gustavus  III. at  Stock-
holm, is formed of it.
  2.  Conchoidal hornstone.   Colours  gray,
white, and red.   Massive, stalactitic, and
rarely in  supposititious  crystals,  whose
figures originate from  calcareous  spar.
Lustre glimmering.   Fracture conchoidal.
Less translucent than the preceding kind,
but somewhat harder.  Rather difficultly
frangible.  Sp. gr. 2.58.  It occurs  in me-
talliferous  veins and agate veins, and along
with clay-stone in the Pentland-hills.
  3.  Woodstone.   Colours  ash-gray and
grayish-black. The various shades of co-
lour, are in clouded and  striped delinea-
tions.  It occurs in  rolled pieces, and  in
the shape of trunks,  branches  and roots.
Surface uneven. Dull or glistening.  Cross
fracture, imperfect  conchoidal; longitudi-
nal,  fibrous.   Translucent on  the edges.
Hard in a low degree.  Rather difficultly
frangible.  Sp. gr. 2.63.  It is found im-
bedded in  sandy loam in alluvial soil.  It
occurs near Lough  Neagh, in Ireland;  at
Chemnitz and Hilbersdorf, in Upper Saxo-
ny.  It receives a good polish.*—Jameson.
  * Horseradish Root, yields by dis-
tillation, an acrid oil, denser than water.*
  * Hospital Ulcer, the matter of, con-
sists of a  peculiar  morbid  secretion.   It
has been successfully treated  by washing
with dilute nitrate of mercury, nitric acid,
and aqueous  chlorine.*
  •  Humite.  A mineral of  a  reeldish-
brown colour, which occurs  crystallized
in octohedrons, more or less truncated  or
bevelled.   Planes  transversely streaked.
Lustre shining.   Transparent.  Scratches
quartz with difficulty.  It occurs at  Som-
ma, near Naples, in a rock composed  of
gray-coloured granular  topaz.   It  was
named by Count Bournon, in honour of Sir
Abr. Hume, Bart, a distinguished cultiva-
tor of mineralogy.*
  * Hyacinth.   A  sub-species of pyra-
midal zircon.  Colours, red, brown,  more
rarely yellow, green, and gray.   It occurs
in angular grains, and crystallized in a rec-
tangular four-sided prism, variously acu-
minated or truncated.  Crystals are small.
Lustre specular-splendent.  Cleavage four-
fold.  Fracture small  conchoidal.  Semi-
transparent or transparent, and  refracts
double.  Harder  than quartz,  but  softer
than topaz.  Rather easily frangible.  Sp.
gr.  4.6 to  4.78.  Before the blow-pipe  it
loses its colour, but not its  transparency,
and is infusible.  Its constituents are,
           from Ceylon,    from Expailly.
Zircon,       70.00              66.00
Silica,       25.00              31.00
Oxide of iron,  0.50               2.00
Loss,         4.50               1.00
             100.00             100.00
            Klaproth.          Vauquelin.
   It occurs imbetlded in gneiss and syenite,
 in basalt and lava, and dispersed through
 alluvial soil; in Auvergne; near Pisa; in the
 trap  rocks round Lisbon; by  Professor
 Jameson in a rolled mass of syenite in the
 shire of Galloway; and abundantly in  Cey-
 Ion.
   The  darker  varieties are deprived  of
 their colour by heat, a fact of which artists
 avail themselves to make zircon resemble
 diamond.  It is esteemed as one  of the
 gems by lapidaries.—Jameson.*
   *  Hyalite.   Colours yellowish  and
 grayish-white.  Generally small  reniform,
 botrioidal, or stalactitic.  Lustre splendent.
 Fracture  small conchoidal.  Translucent.
 Moderately hard.  Sp. gr. 2.2.  Infusible
 before the blow-pipe. Its constituents are,
 92 silica, 6.33 water.  It has been hitherto
 found principally  near Frankfort on the
 Maine, where it occurs in fissures in vesi-
 cular basalt and basaltic greenstone.  It is
 cut into ringstones.*
   * Hydrargyllite.   Wavellite*
   * Hydrates.   Compounds, in definite
 proportions, of metallic oxides  with wa-
 ter.*
   *  Hydriodates.   Salts consisting  of
 hydriodic acid, combined in definite  pro-
 portions with oxides.*
   * Hydriodic Acid.  See Acid (Hy-
 driodic) and  Iodine.*
   * Hydrochloric Acid.  Muriatic acid
 gas; a compound  of chlorine and  hydro-
 gen.*
   *  Hydrocyanic Acid.   See Acid
 (Prussic).*
   * Hydrogen Gas.   The  lightest  spe-
 cies of ponderable matter hitherto known.
 It was  discovered by  Mr. Cavendish  in
 1766.  It can be procured  only from wa-
 ter, of which it forms an essential consti-
 tuent.
   Into a phial furnished with a bent tube
 fitted to its cork, or into a retort, put some
 pieces of pure  redistilled zinc, or harpsi-
 chord iron wire, and pour on them sulphu-
 ric acid diluted with 5 times  its bulk  of
 water.  An effervescence will ensue, occa-
 sioned by the decomposition of the  water,
 and  disengagement  of hydrogen,  which
 may be collected in the  pneumatic appa-
 ratus.  For  very  accurate researches,  it
 must be received  in jars  over  mercury,
 and exposed to the joint action of dry mu-
 riate of lime, and a low temperature.  It
 is thus freed from  hygrometric water.  In
this state its specific gravity is 0.0694  at 
HYD                                HYD
60* F. and 30 inches of barom. pressure.
100 cubic inches weigh 2.118 grains.  It
is  therefore about 14.4 times less  dense
than common air; 16 times less dense than
oxygen, and 14 times less dense than azote.
In the article Gas, I have shown, that when
it  stands over water at 60°, its sp. gr. ac-
quires an increase of nearly  one-seventh;
and it becomes about  0.0790.  From the
great rarity of hydrogen,  it  is employed
for the purpose of inflating varnished silk
bags, which are raised in the  air, under
the name of balloons. See Aerostation.*
   This gas is colourless, and possessed of
all the physical properties of air.   It has
usually  a slight garlic  odour, arising pro-
bably from  arsenical particles derived from
the zinc.  WThen water is transmitted over
pure iron  in a  state of ignition, it yields
hydrogen free from smell.   It is eminently
combustible, and, if pure,  burns with a
yellowish-white flame; but from accidental
contamination,  its flame has frequently a
reddish tinge.  If a narrow jar filled with
hydrogen,  be lifted perpendicularly, with
the bottom upwards, and  a  lighted  taper
be suddenly introduced, the taper will be
extinguished, but the gas will burn at the
surface, in contact with the  air.   Animal
life  is likewise  speedily extinguished by
the respiration of this gas, though Sir H.
Davy has shown, that if the lungs be not
previously  exhausted by a forced expira-
tion, it may be breathed for a few seconds
without much seeming inconvenience. For
its point of accension, see Combustion;
and for its habitudes with liquids and so-
lids, see Gas.
   When five measures of atmospheric air
are  mixed  with two  of hydrogen, and  a
lighted taper, or an electric spark, applied
to the mixture, explosion takes place, three
measures of gas disappear,  and  moisture
is deposited on the  inside  of the glass.
When two measures  of hydrogen, mixed
with one  of oxygen, are detonated,  the
whole is condensed into water. Thus, there-
fore, we see the origin of the name hydro-
gen, a term derived from the Greek to de-
note the water-former.  See Water.  If a
bottle containing the effervescing mixture
 of iron and dilute sulphuric  acid, be shut
 with a cork, having a  straight tube of nar-
 row bore fixed upright in it, then the hy-
 drogen will issue in a jet, which being
kindled, forms the philosophical candle of
 Dr. Priestley.   If a long glass tube be held
 over the flame,  moisture will speedily be-
 dew its sides, and harmonic tones will soon
 begin to sousjsl.   Mr. Faraday, in an inge-
 nious paper inserted in the 10th number of
 the Journal of Science, states, that carbo-
 nic oxide  produces, by the action of its
 flame, similar sounds, and  that  therefore
 tlie effect  is not due  to the affections of
 aqueous vapour, as had formerly  been sup-
posed.  He shows, that the sound is  no-
thing more than the report of a continued
explosion, agreeably to Sir H. Davy's just
theory of the  constitution  of flame.  Va-
pour of ether, made to burn from  a  small
aperture, produces  the same sonorous ef-
fect as the  jet of hydrogen, of coal gas, or
olefiant gas,  on  glass  and other tubes.
Globes from seven  to two inches in dia-
meter, with short  necks,  give  very low
tones; bottles, Florence flasks and phials,
always succeeded; air jars from four inches
diameter to a very small size, may be used.
Some angular tubes  were constructed of
long narrow slips of glass  and wood, pla-
cing three  or four together, so as  to form
a triangular or square  tube,  tying them
round with pack-thread.  These held over
the hydrogen  jet, gave distinct tones.
Hydrogen, combined  with oxygen,
   With    forms water.
Chlorine,        muriatic acid.
Iodine,          hydriodic acid.
Prussine,        prussic acid.
Carbon,          subcarb. and carb. hydr.
Azote,           ammonia.
Phosphorus,     subphos. and phos. hydr.
Sulphur,         Sulph. and subsul. hydr.
Arsenic,         arsenuretted hydrogen.
Tellurium,      telluretted hydrogen.
Potassium,      potassuretted hydrogen.
   For an  account  of these several com-
pounds, see the  respective bases.  From
the proportion in  which  it combines with
these bodies,  its prime  equivalent on the
oxygen radix, is  fixed at 0.125.  It is the
body which gives  the  power  of burning
with flame to all the substances used for
the economical production of heat and light.
   In that invaluable repository of  philoso-
 phical facts, Tilloch's Magazine,  we have
 the following notice ofthe effect of hydro-
 gen gas on the voice: " The Journal Bri-
 tannique, published at Geneva by  Prevost,
 contains the  following article:  ' Maunoir
 was one day amusing himself with Paul at
 Geneva, in breathing pure hydrogen air.
 He inspired it with ease, and did  not per-
 ceive that it had any  sensible effect on him,
 either in entering his lungs, or passing out.
 But after he had taken in  a very large dose,
 he was desirous of speaking, and  was asto-
 nishingly  surprised  at the  sound  of his
 voice, which  was become soft, shrill, and
 even squeaking, so as to  alarm him. Paul
 made the  same experiment on himself, and
 the same effect was  produced:   I do not
 know whether any thing similar has oc-
 curred in  breathing  any of the other gas-
 es.'"  Vol. iv. page 214.
    In the article  arsenuretted hydrogen, un-
 der Arsenic, in this work, a sentence at
 the middle of the column should read thus,
 " By subtracting from the specific gravity
 ofthe  arsenuretted gas, that  of hydrogen
 gas  X  Toh we nave tne proportion  of 
HYD                                  HYD
arsenic present;  0.55520 —  0.09716 =
0.45804 = the arsenic in 100  measures of
arsenuretted hydrogen;  which  gives the
proportion by weight of  about five arsenic
to one hydrogen," &c*
  * Hydroguret of sulphur.  See  SUL-
PHUR.*
  Hydrometer.  The  best  method of
weighing equal quantities of corrosive vo-
latile fluids, to determine their specific gra-
vities, appears to consist  in enclosing  them
in a bottle with a conical stopper, in the side
of which stopper a fine mark is cut with a
file.  The fluid being poured into  the bot-
tle; it is easy to put in the stopper, because
the redundant  fluid  escapes through the
notch, or*nark, and may be carefully wiped
off. Equal bulks of water, and other fluids,
are by this means weighed to  a great de-
gree of accuracy, care being taken to  keep
the temperature as  equal  as  possible, by
avoiding any contact  of the bottle with the
hand, or otherwise.  The bottle itself shows
with much precision, by a rise or fall of the
liquid in the notch of the stopper, whetlier
any such  change have taken  place.   See
Specific Gravity and Alcohol.
  The hydrometer of Fahrenheit consists of
a hollow ball, with a counterpoise below,
and a very slender stem above, terminating
in a small dish.  The middle, or half length
of the stem, is distinguished by a fine line
across.  In this instrument every division of
the stem is rejected, and it  is immersed in
all experiments to the middle of the stem,
by placing proper weights in the  little dish
above.  Then, as the part immersed is con-
stantly ofthe same magnitude, and the whole
weight of the hydrometer is known, this last
weight  added to the  weights in the dish,
will be equal to the weight of fluid displaced
by the instrument, as all writers on hydros-
tatics prove.  And accordingly, die  sp. gra-
vities for the common form of the tables will
be had by the proportion:
    As the  whole weight of the hydrometer
      and its load, when adjusted in distill-
      ed water,
    Is to the number  1000,  Sec.
    So is the whole weight when adjusted
      in any other fluid,
    To  the number expressing its  specific
      gravity.
  The hydrometers, OTpese-liqueurs, ofBaume,
though in reality comparable with each other,
are subject in part to the defect, that their
results,  having no  independent  numerical
measure, require explanation to those who
do not know the instruments. -
        BaumPs Hydrometer for Spirits.

Temperature 55° Fahrenheit, or 10° Reaumur.
Deg.	Sp. Grav.	Deg.	Sp. Grav.	Deg.	Sp. Grav.	Deg.	Sp. Grav	Deg. Sp. Gray.
10	= 1.000	17	= .949	23	= .909	29	= .874	35 _ .842
11	.990	18	.942	24	.903	30	.868	36 .837
12	.985	19	.935	25	.897	31	.862	37 .832
13	.977	20	.928	26	.892	32	857	38 .827
14	.970	21	.922	27	.886	33	.852	39 .822
15	.963	22	.915	28	.880	34	.847	40 .817
16	.955							
  With regard to the  hydrometer for salts,
the learned author of the first part of the
Encyclopaedia, Guyton de Morveau, who by
no means  considers this an accurate instru-
ment,  affirms, that the sixty-sixth degree
corresponds nearly with a  specific gravity
of 1.848; .and  as this  number lies near th«
extreme of the scale, I shall use it to deduce
the rest.
        Baume"s Hydrometer for Salts.

Temperature 55° Fahrenheit, ot 10° Reaumur.
Deg.  Sp. Grav.
  0= 1.000
  3
 6
 9
12
1.020
1.040
1.064
1.089
Deg. Sp. Grav
 15= 1.114
 18    1.140
 21    1.170
 24    1.200
 27    1.230
Deg. Sp. Grav.
 30 =  1.261
 33     1.295
 36     1.333
 39    n.373
 42     1.414
Deg. Sp.Grav
 45 =  1.455
 48     1.500
 51     1.547
 54     1.594
 57     1659
Deg. Sp.Grav.
 60 = 1.717
 63    1.779
 66    1.848
 69    1.920
 72    2.000
  It may not  be amiss to add, however that  of an areometer of Battml by actual trial;
in the Philosophical Magazine, Mr. Bingley,  temperature about 60° Fahr.   But bis ap-
the assay-master of the mint,, has given the  pears to  have  been a different instrument)
following numbers as the specific gravity of  as it was graduated only from 0 to 5#°.
nitric acid,  found to answer to the degrees
      voi.  II*.                                                 1*4 
JAS
JAS
D.cg.  Sp. Grav.| Deg. Sp.Grav.  Deg. Sp.Grav-
 is =  1.150     29 =  1.250  ,  34 =  1.300
 20     1.167  |  30     1267  !  35     1.312
 26     1.216  I  31     1.275  j  36     1.333
 23     1.233  i  32     1283  |  37     1.342
Deg. Sp.Grav
 38=  1.350
 39     1.358
 40     1.367
 41     1.383
Deg.  Sp.Grav.
 42  = 1.400
 43     1416
 45     1.435
  There are  a variety of hydrometers used
for determining the strength of ardent spi-
rit.  See Alcohol and Distillation-.
  * Hydrophane.  A  variety of opal, which
has the property of becoming transparent
on immersion in water.  It is also called ocu-
lus mundi.  We must be careful to immerse
them only in pure  water,  and  to withdraw
them whenever they have acquired  their
full transparency.   If we neglect these pre-
cautions, the pores  will soon become filled
with earthy particles deposited from the wa-
ter, and the hydrophane will cease to exhi-
bit this curious property, and will remain al-
ways more or less opaque.*
  * Hydrosulphurets.  Compounds of sul-
phuretted hydrogen with  the  salifiable  ba-
ses.*
  * Hydrothionic Acid.  Sulphuretted hy-
drogen, the hydrosulphuric acid of  M. Gay-
Lussac*
  * Hyosciama.   A new  vegetable alkali,
extracted by Dr. Brandes from the  hyoscia-
mus  nigra, or henbane.  It crystallizes in
long prisms, and when neutralized by  sul-
phuric acid, or nitric acid, forms character-
istic  salts.—The examination of the  alkaline
constituents of  narcotic  plants demands
great circumspection, because in them the
whole poisonous properties of the plant are
concentrated.   The  vapour is particularly
prejudicial to the eyes.  The  smallest mor-
sel put upon the tongue, is very dangerous.*
  * Hyperstene.   Lahradore schillerspar.
Colour between grayish and greenish-black,
but nearly copper-red on the cleavage. Mas-
sive, disseminated, and in thin curved lamel-
lar concretions. Lustre shining, metallic, pear-
ly. Cleavage double oblique angular. Opaque.
Streak greenish-gray. Hard asfeldspar. Brit-
tle. Sp. gr. 3.4. Infusible before the blow-
pipe. Its constituents are,  54.25 silica, 14
magnesia, 2.25  alumina, 1.50 lime, 24.5 ox-
ide of iron, 1 water, and a  trace of manga-
nese. It has been found in Labradore, Green-
land,  and by Dr. M'Culloch in  the Isle of
Skye.  It has a beautiful copper-red colour
when cut  and  polished into ringstones or
broaches.*
  * Hypophosphorous Acid. See Acid (Hy-
pophosphorous.)*
  * Hyposulphdkocs Acid.  See Acid (Hr«
rosuLPHURors.)*
  * Hyposulphuric Acid.  See  Acid  (Hy-
posulphuric,) which three acids are treated
of under the phosphoric and sulphuric.
I&J.
*TADE.  See Nephrite.*
 **     Jalap.  A  root used  in medicine
as a purgative. By M. Henry's analysis, the
constituents of three different varieties  of
this root are,
              Jal. \rget.   Jal. sain. Jal. piqae.
  Resin,         60       48       72
  Extract,       75       140      125
  Starch,        95       102      103
  Woody fibre,  270       210      200

                500       500      500*
  * Jargon.  See  Zircon.*
  * Jasper.   A sub-species of the rhomboi-
dal quartz of Professor Jamesan.  He enu-
merates five kind1-: Egyptian jasper, striped,
porcelain, common, and agate jasper.
  1- Egyptian jasper, of which there is reel
and  brown.   The first is flesh-red, blood-
red, yellow, and brown, in ring-shaped de-
lineations.  In roundish pieces. Dull. Frac-
ture conchoidal.  Feebly translucent on the
edges   Haiti.  Easily frangible.   Sp.  gr.
 2.63.  It is  found imbedded in red clay-
ironstone  at Baden,  and  is cut into  orna-
ments.
  The brown has its various shades of co-
lour disposed in concentric stripes, alterna-
ting with  black  stripes. In spheroidal mas-
ses.   Lustre  glimmering.   Fracture con-
choidal.   Feebly translucent on the edges.
As hard as hornstone. Sp. gr.  2.6.   It is
infusible.   It occurs loose in  the sands  of
Egypt. It is cut into ornaments.
   2.  Striped jasper.   Colours, gray, green,
yellow, red, arranged  in stripes,  in flamed
or spotted delineations.  Massive in whole
beds.   Dull.  Fracture conchoidal. Opaque.
Less hard than Egyptian jasper. Rather ea-
sily frangible.   Sp. gr. 2.5.  It occurs  in se-
condary clay-porphyry in the Pentland-hills,
and near Friburg in  Saxony."  It  receives a
fine polish.
   3 Porcelain jasper.  Colours gray,  blue,
yellow, generally of  one colour, or with
clouded delineations.  Massive, and cracked
in all directions. Lustre glistening.  Frac-
ture  conchoidal.  Opaque.  Easily frangi- 
IND
IND
  ble, and not very hard.  Sp. gr. 2.5.  Fuses
  into a white or gray glass.  Its constituents
  are 60.75 silica, 27.25 ahimina, 3 magnesia,
  2.5 oxide of iron, and 3.66 potash.   It is al-
  ways found along with burnt clay and earth
  slags.  According to Werner, it is slate-day
  converted  into a kind  of porcelain, by the
  heat of a pseudo-volcano, from beds of burn-
  ing coal    It is fnund on the coast  of Fife-
  shire, in Shropshire, and Warwickshire, and
  some  parts of Germany,  where  immense
  beds of coal appear.
   4. Common jasper. Colours red and brown.
  Massive.  Lustre, from shining to dull.  Frac-
 ture conchoidal.   Opaque.   Hard in a low
 degree. Ruther easily frangible. Sp. gr. 2.6.
 Infusible before the blow-pipe, becoming it
 last white.   It occurs principally in veins as
 a constituent of agate.  It is found in the
 Pentland-hills,  and in  trap  and transition
 rocks  in \\rshire  and Dumfries-shire.  It
 receives a good polish.
   5. Agate jasper.   Colours yellowish-white
 and reddish-white.  Massive.  Dull.  Frac-
 ture flat conchoidal.   Opaque.  Hard  in a
 low degree. It occurs in layers in agate
 balls, in many places.*
   Ice.  See Caloric, Thermometer,  Wa-
 ter.
   •Iceland Spar.  See  Calcareous Spar*
   *Ice-spah. A sub-species of feldspar.*
   * Ichthyophthai.^ite. See Apophyllite.*
   Iciithyocolla. Fish glue or Isinglass.
   ♦Iiiochase.  See  Vesuvian.*
   * Jelly, of ripe currants and other berries;
 a compound of mucilage and acid, which
 loses  its  gelatinizing power by long  boil-
 ing.*
   *Jenite. See Lievrite.*
   ♦Jet. See Pitch  Coal.*
   Ignis Fatuc.v  A luminous appearance
 or flame, frequently seen in  the  night in
 different country places, and  called  in Eng-
 land  Jack with a lantern, or  Will with the
 wisp.  It seems to  be mostly occasioned by
 the extrication of phosphorus from  rotting
 leaves  and  other vegetable  matters.  It is
 probable, that the motionless ignes fatui of
 Italy which are seen nightly on the same
 spot, are produced  by the slow combustion
 of sulphur, emitted through clefts and aper-
 tures in the soil of that volcanic country.
   Incineration.  The combustion of vege-
 table  or  animal substances, for  the pur-
 pose of obtainng their ashes or fixed resi-
 due.
   Incombustible  Cloth  See Asbestus.
   Indigo.    A  blue colouring  matter  ex-
 tracted  from a plant called Anil, or  the In-
digo Plant.
   In the preparation of this drug, the herb
is put into a vat or cistern, called the steep-
ing trough,  and there covered  with water.
The  matter  begins  to  ferment sooner or
later, according  to  the  warmth   of  the
 weather and the maturity ofthe plant; soraeo
 times in six or eight hours, and sometimes
 in not less than twenty.  The liquor grows
 hot,  throws  up  a  plentiful  froth, thick-
 ens by degrees, and acquires a blue colour
 inclining  to  violet.  At this time,  without
 touching the herb,  the  liquor impregnated
 with its tincture,  is let out by cocks in the
 bottom into another vat placed for that pur-
 pose, so as to be commanded by the first.
   In the second vat, called the beating vat,
 the liquor is strongly and incessantly beaten
 with a kind of buckets fastened to poles, till
 tlie colouring matter is united into a body.
   As soon as it is judged, from the blue co-
 lour of the liquid, that the beating  is suffi-
 cient, it is left at rest for two hours; after
 which ihe clear liquor is drawn off bv cocks
 in the side of the vat, and the blue" part is
 discharged by another cock into a third vat,
 where it is suffered to settle for some  time
 longer;  then  conveyed in a half  fluid state
 into bags of cloth, to strain  off' more of its
 moisture;  and lastly, exposed  to  the air in
 the shade  in shallow wooden boxes, till it is
 thoroughly dry.
   Bergmann examined this drug.  He found,
 that one-ninth part of the indigo  was taken
 up by boiling it in water.  The  parts  dis-
 solved were partly mucilaginous,  partly as-
 tringent and  partly saponaceous.  The so-
 lution of alum,  and of sulphate of iron as
 well as of copper, precipitate the  astringent
 portion.
   Bergmann mixed one part of well pulver-
 ized  indigo with  eight  parts of  colourless
 sulphuric acid,  of the  specific gravity of
 1.900, in a glass vessel slightly closed.  The
 acid very  quickly acted  upon the  indigo,
 and excited much heat.  Aft er a digestion
 of twenty-four hours, the solution  was ef-
 fected; but the mixture was  opaque  and
 black.
   If the sulphuric acid  be  first diluted in
 the water, it attacks only the earthy prin-
 ciple which is mixed with the indigo,  and
 some of the mucilaginous parts.
   The fixed alkalis saturated with carbonic
 acid, separate a very tine blue powder from
 the solution of indigo,  which  is deposited
 very slowly
  The concentrated  nitric acid attacks in-
 digo with so much activity, as to set it on fire.
  The muriatic acid by digestion,  and even
boiling upon  indigo,  takes  up  only  the
earthy matter, the iron, and a little of the
extractive matter,  which gives it  a  brown
colour, but in no  respect attacks  the blue
colour.
  Pure or  caustic fixed  alkali   dissolves
 some matters foreign to the colouring mat-
ter ofthe indigo, but acts very little  on the
colouring  particles.   Pure  volatile   alkali
has nearly the same effect.  Precipitated
indigo  is speedily dissolved in the  cold,  in 
IND                                     IND
tke alkalis, whether fixed or  volatile, if
pure  or caustic.  The  blue colour  is gra-
dually changed  to a green, and at last de-
stroyed.
  Bergmann concludes, from his analysis,
that 100 parts of good indigo contain of mu-
cilaginous matter, separable by water 12,
resinous matter  soluble in  alcohol 6, earthy
matter taken  up by the acetic acid, which
does  not attack the  iron,  here in the state
of oxide, 22, oxide of iron taken up by the
muriatic acid 13.
  There remained 47 parts, which are the
colouring matter, nearly in a state of puri-
ty,  and afforded by  distillation, carbonic
acid 2, alkaline  liquor 8, empyreumatic oil
9, coal 23.
   The solubility of indigo in alkalis, ap-
pears to be produced  by the abstraction of
part of the oxygen it  had absorbed.  This
appears to be well established from the expe-
riment of Bergmann, wherein equal weights
of  sulphate of iron and indigo,  and double
the weight of lime, are mixed together in
water, and produce a solution ofthe indigo
in  the  lime-water.  But if the iron of the
sulphate, be previously oxidized to a higher
degree, by boiling it in much water for se-
veral hours,  and subsequent evaporation,
 the solution will not  be  effected, because
 the precipitated iron is no longer disposed
 to  absoro oxygen.  Or  again, if indigo be
 added to a solution  of caustic fixed alkali,
 and orpiment be added (which consists of
 arsenic and sulphur,)  the  indigo is soon dis-
 solved, and  takes a  green colour.  If the
 arsenic corresponding with the orpiment be
 only added,  the bath  will never be fit for
 the dyer; but if the  quantity of sulphur it
 ought to contain be added, the appearances
 of solution will speedily be had.
    It follows,  therefore,  that indigo contains
 oxygen in its natural state; that in this state
 it  will not unite with  lime or alkalis; but
 that substances capable of depriving it  of
 part of its oxygen, render it soluble in lime
 or alkalis; and  lastly, that  the natural state
 of the indigo  is restored by the contact of
 oxygen which  it absorbs.  In this  last  way
 it is that the blue dye is effected. The piece
 comes out of the vat of the same colour  as
 the solution; viz green;  but becomes blue
 by exposure to the air. The alkali, or lime,
 is carried off" by the  washing, and the indi-
 go remains combined with the stuff', by this
 means dyed.
    * M. Chevreul has given the following re-
 sults of a very elaborate analysis of Guati-
  mala Indigo.
f Ammonia,            12
1 Disoxygenized indigo,
1 Green matter,
( Bitter matter,
                 {Green matter,        <»■
                 Red matter,
                 Indigo,
t>      - ♦•„  „m \ Ked matter,           6
By muriatic acid ) Carbonate ^f lime>     2
               Oxide of iron and alumina, 2
               Silica,                   3
               Pure indigo,            45

                                      100
  When commercial indigo is exposed to a
heat of about 400°  F. it evolves a beautiful
crimson smoke, which may be condensed in
crystalline needles,  which are supposed to
be pure indigo.  The  blue vat ofthe  dyer
contains indigo deoxidized by protoxide of
iron, and rendered soluble in its yellow-green
state by lime-water.  If a portion of this so-
lution  be exposed  in  the air, in a shallow
vessel, the indigo will speedily absorb oxy-
gen, and precipitate in its usual state of an
insoluble blue  powder.  This  being dried,
and digested  in a mixture  of alcohol and
muriatic acid, becomes also pure indigo, by
the abstraction of all the resin and lime. In
this state, it is  a soft powder, of an intense.
ly deep blue, verging sometimes on purple.
It is unchangeable by the air.  Every sub-
stance which has a  great affinity for oxygen,
when  digested with indigo, deprives it of the
blue colour,  and converts it, either perma-
nently or for a time, to a yellow or greenish-
yellow hue.   Thus, if into  the sulphate of
indigo above described, are put a few pieces
of iron or zinc, the nascent hydrogen seizes
its oxygen, and  discolours  it.   Sulphuric
acid,  rendered  smoking by a  little sul-
 phurous  acid,  is a better solvent of indigo
 tlian pure oil  of vitriol.  By boiling a lit-
 tle  sulphur  in this,  its solvent  power is
 improved.  Nitric  acid, digested on indigo,
 converts it into Mr. Hatchett's artificial tan-
 nin, a bitter principle, with  oxalic and ben-
 zoic acids.
    When indigo  is  mixed  with  liquid fer-
 mentable materials, it is speedily deoxidized
 Bergmann showed long ago, that no gas, ex-
 cept  carbonic acid,  was disengaged from
 the distillation  of indigo in close vessels.
 This  seems to coincide with Dr. Thomson's
 late analysis, in which he exposed pure indi-
 go to the action of ignited peroxide of cop-
 per,  and collected the gaseous products,
 which led him to assign the following as its
 composition:—
Oxygen,
Carbon,
Azote,
 46.154
 40.384
 13.462

100.000
By water
  The total want of hydrogen in Uiis vege-
table substance, is a veiy singular and inter-
esting result.   He says, that indigo, in the 
INK                                     INK
 state of a greenish-yellow soluble pigment, is
 composed of 5 atoms Oxvgen,  5.00
             7       Carbon,  5.25
             1       Azote,   1.75

                              12.00

   The addition of a single atom of oxvgen,
 renders  the  pigment  blue and  insoluble.
 " Thus," adds he," indigo exhibits a striking
 refutation of the old notion, that acidity is
 owing to the union of oxygen with an acidi-
 fiable basis.  Blue indigo approaches  much
 nearer to the nature of a salifiable base, than
 an acid; but deoxidized indigo,  seems to
 possess acid powers, for it becomes capable
 of uniting with alkalis, and alkaline earths."
 Annals of Philosophy for June 1820.*
   Ink.   Every liquor  or pigment used for
 writing  or printing, is distinguished by the
 name of ink.  Common practice knows only
 black and red.
   Of black ink there are three principal
 kinds: 1. Indian ink; 2. Printer's ink; and,
 3. Writing ink.
   The Indian ink is used in China for writ-
 ing with a brush, and for painting upon the
 soft flexible paper of Chinese manufacture.
 It is ascertaineel, as well from experiment as
 from information, that the cakes of this ink
 are made of lampblack and size, or animal
 glue, with the addition of perfumes or other
 substances not essential to its quality  as an
 ink. The fine soot from the flame of a lamp
 or candle, received  by holding a plate over
 it, mixed with clean size from shreds of parch-
 ment or glove-leather not dyed,  will  make
 an ink equal to that imported.
   Good printer's ink is a black paint, smooth
 and uniform in its composition, of a firm black
colour, and possesses a singular aptitude to
adhere  to  paper thoroughly  impregnated
with moisture.
  The consistence and tenacity ofthe oil in
this composition are greatly increased, and
its greasiness diminished, by means of fire,
Linseed  oU or nut oil is made choice of for
this use.  The nut oil is supposed to be the
best, and is accordingly preferred for  the
black ink, though the darker colour it ac-
quires from the fire renders it less fit for the
red. It is said, that the other expressed oils
cannot be sufficiently freed from their  unc-
tuous quality.
  Ten or twelve gallons of the oil are set
over the fire in an iron pot, capable of hold-
ing at least half  as much more; for the oil
swells up greatly, and  its boiling  over into
the fire would be very dangerous.   When
it boils, it is kept stirring with an iron ladle;
and if it do not itself take fire, it  is kindled
with a piece of flaming paper or wood; for
simple boiling, without the actual  accension
ofthe oil, does not communicate asufticient
degree ofthe drying quality required.  The
oil is suffered  to burn  for  half an hour or
 more, and the flame being then extinguish-
 ed by covering the vessel close, the boiling
 is afterward continued  with  a gentle heat,
 till the oil appears of a proper consistence;
 in which state it is called varnish.  It is  ne-
 cessary to have two kinds of this varnish, a
 thicker and a thinner, from the greater or
 less boiling, to  be occasionally  mixed  to-
 gether, as different purposes may require;
 that which answers well in hot weather be-
 ing too thick in cold, and large characters
 not requiring so stiff an ink as small ones.
   The thickest varnish,  when cold, may be
 drawn into threads like weak glue; by which
 criterion the workmen judge of the due boil-
 ing, small quantities being from time to time
 taken out and dropped upon a tile  for  this
 purpose.   It is  very  viscid and tenacious,
 like the soft resinous juices, or thick turpen-
 tine.   Neither water nor alcohol dissolves
 it; but it  readily enough mingles with fresh
 oil, and unites with mucilages into a mass
 diffusible in water  in  an  emulsive  form.
 Boiling with caustic alkali produces a soapy
 compound.  It is by washing with hot soap-
 lees and a brush that the printers clean their
 types.  The oil loses from one-tenth to one-
 eighth of its weight by the boiling into  the.
 thick varnish.
  It is affirmed, that  varnish containing ei-
 ther turpentine or litharge, particularly  the
 latter, is more adhesive than other varnish,
 and presents a great difficulty in cleaning
 the types, which soon become clogged. Very
 old oil requires neither of these additions.
 New  oil can  hardly be brought into a pro-
 per state  for drying, so as  not to set  off,
 without the use of turpentine.
  Lampblack is the common material to
 give the black colour, of which two ounces
 and a half are sufficient for sixteen  ounces
 of the varnish.   Vermilion  is a good red.
 They are ground together on a stone with a
 muller, in the same manner as oil paints.
  The ink used by copperplate printers  dif-
 fers in the oil, which is not so much boiled
 as to   acquire the adhesive quality.   This
 would render it less disposed to enter  the
 cavities ofthe engraving, and more difficult
 either to be spread or wiped off. The black
 is Ukewise of a  different kind.  Instead of
 lampblack, or sublimed charcoal, the Frank-
 fort black is used, which is a residual or den-
 ser charcoal, said to be made from vine-twigs.
 This is softer and less gritty than the  ivory
 or other blacks prepared among us, and, no
 doubt,  contains  more coal than any  animal
 residue, as all these abound with phosphate
 of lime.  It  is said, that lampblack gives
 always a degree  of toughness to  the  ink,
 which the Frankfort black does not, but the
 goodness of the colour seems to be the lead-
 ing inducement for the use of the latter.  A
 pale or brown black can be much more  ea-
sily endured in a book, than in the impres-
sion of an engraving. 
INK                                    INK
  We have no good explanation  of what
happens with regard to the chemical effect
of boiling and burning upon the oil for print-
ers' use.
  Common ink for writing is made by add-
ing an infusion  or decoction of the nut-gall
to sulphate of iron, dissolved  in water.   A
very fine black precipitate is thrown down,
the speedy subsidence of which is prevented
by the addition of a proper quantity of gum-
arabic.  This is usually accounted for by the
superior affinity of the gallic  acid, which,
combining with the iron,  takes it from the
sulphuric, and falls down.  But it appears
as if this were not the simple  state  of the
facts; for the sulphuric acid in  ink is not so
far disengaged as to act speedily upon fresh
iron, or give other manifestations of its pre-
sence  in an uncombined state. According
to Deyeux, the iron in ink is  partly in the
state of a gallate.
  M. Ribaucourt paid particular  attention
to the process  for making black ink, and
from his experiments he draws  the following
inferences:—That logwood  is a useful  in-
gredient in ink, because its colouring matter
is disposed to unite with the oxide  of iron,
and renders it  not only of a very  dark co-
lour, but less capable of change from the ac-
tion of acids, or of the air.  Sulphate of cop-
per, in a certain proportion, gives depth and
firmness to the colour ef the ink.  Gum-ara-
bic, or any other pure gum, is of service, by
retarding the precipitation ofthe feculx: by
preventing the ink from spreading or sink-
ing into the paper;  and by aff'oraing it a
kind of compact varnish, or defence from the
air when dry.   Sugar appears  to have some
bad qualities, but is of use in  giving a de-
gree of fluidity to the  ink, which permits
the dose of gum to  be  enlarged  beyond
what the ink would bear without it.   Water
is the best solvent.
  Lewis had supposed, that the defects of
ink arise chiefly from a want  of colouring
matter.  But the theory,  grounded on the
fact discovered by  M Ribaucourt,  requires
that none ofthe principles should be in ex-
cess.
  It is doubtful whether  the  principles of
the galls, be well extracted  by maceration;
and it is certain, that inks made in  this way
flow pale from the  pen, and  are not of so
eleep a black as those wherein strong boil-
ing is recurred to.
  From all the  foregoing  considerations M.
R. gives these directions for the composition
of good ink:—
  Take  eight  ounces of Aleppo galls  fin
coarse powder;) four ounces of logwood (in
thin chips;)  four ounces of sulphate of iron;
three ounces of gum-arabic (in powder;)
one ounce of sulphate of copper;  and one
ounce of sugar-candy.  Boil the galls and
logwood together in twelve pounds of wa-
fer for one hour, or till half the liquid has
evaporated.   Strain the decoction through a
hair sieve, or linen cloth, anel then add  the
other ingredients.   Stir the mixture, till the
whole is dissolveei, more especially the gum;
after which, leave it to subside for twenty.
four hours.  Then decant the ink, and pre-
serve it in bottles of glass or stone ware, well
corked.
  Many recommend, that the sulphate of iron
should be calcined to whiteness.  Mr. Desor-
meaux, jun. an ink manufacturer in Spital-
fields, has given the following in the Philo-
sophical  Magazine, as  the result  of much
experience:—Boil  four  ounces of logwood
about an  hour in six beer quarts of water,
adding boiling  water  from time to time;
strain while  hot; anel when cold  add water
enough to make the liquor five quarts.   In-
to this put one pound avoirdup. of blue galls
coarsely bruised; four ounces of sulphate of
iron calcined to whiteness;  three ounces of
coarse brown sugar; six ounces ofguni-ara-
bic; and A mnce of  acetate of copper,  tri-
turated with  a little of the decoction to a
paste, and then thoroughly mixed with  tlie
rest.  This is to be kept in a bottle uncork-
ed about a fortnight, shaking it twice a-day,
after which it may be poured from the dregs,
and corked up for use.
  Dr. Lewis uses vinegar .for his menstruum;
and M. Ribaucourt has  sulphate of copper
among his ingredients.  I have found an in-
convenience from the use of either, which,
though it does not relate to the goodness of
the ink, is sufficiently great, in their practi-
cal exhibition, to forbid  their use. The acid
of the vinegar acts so strongly upon the pen,
that it very frequently requires mending;
and the sulphate of copper has a still more
unpleasant  effect on the penknife.   It  sel-
dom happens when a pen requires mending,
that the ink is wiped very perfectly from it;
and often, when the nib only is to be taken
off, it is done without wiping at all.  When-
ever this is the case, the  ink immediately de-
posites a film of copper upon the  knife, and
by superior elective attraction of the sulphu-
ric  acid, a  correspondent portion of  the
edge of the  knife is dissolved, and is by this
means rendered incapable of  cutting till it
has been again set upon the hone.
  If a little sugar be added to ink, a copy of
the writing may easily be taken off, by lay-
ing a sheet of thin unsized paper,  damped
with  a sponge, on the written paper, and
passing lightly over it a flat  iron very mo-
derately heated.
  Inks of other colours may be made from a
strong decoction of the ingredients used in
dyeing, mixed with a little alum and gum-
arabic.  For example, a strong decoction of
Brazil wood, with as much alum as it  can
dissolve, and a little gum, forms a good red
ink.  These processes  consist in forming a
lake,  and retarding its precipitation by the
gum.   See Lake. 
INK                                   INT
  On many occasions it is of importance to
employ an ink indestructible by any process,
that will not equally destroy the material on
which it is applied.  Mr. Close has recom-
mended for this purpose twenty-five  grains
of copal in powder dissolved in 200 grains
of oil of lavender, by the assistance of gentle
heat, and dien mixed with  two and a half
grains of lampblack,  and half a grain of in-
digo;  or 120 grains of oil of lavender, seven-
teen grains of copal, and sixty grains of ver-
milion.   A litde oil of lavender, or of tur-
pentine, may be added, if the ink be found
too thick.  Mr. Sheldrake suggests, that a
mixture of genuine asphaltum dissolved in
oil of turpentine,  amber varnish, and lamp-
black, would be still superior.
   When writing with common ink has been
effaced by means  of aqueous chlorine, the
vapour of sulphuret of ammonia, or immer-
sion  in water  impregnated with this sul-
phuret, will render it  again legible.   Or,  if
the paper that contained the writing be put
into a weak  solution of prussiate of potash,
and, when it is thoroughly wet, a little sul-
phuric acid be added to the liquor, so as to
render it slightly acidulous, the same pur-
pose will be answered.
   Mr. Haussman has given some composi-
 tions for marking pieces of cotton or linen,
 previous to their being bleached, which are
 capable of resisting  every  operation in the
 processes both of bleaching and dyeing, and
 consequently,  might be employed in mark-
 ing  linen for  domestic purposes.  One  of
 these consists of asphaltum dissolved  in
 about four parts  of oil of  turpentine,  and
 with this is to be mixed lampblack, or black
 lead in fine powder, so as to make an ink of
 a proper consistence for printing with types.
 Another, the blackish sulphate left after ex-
 pelling oxygen gas from oxide of manganese
 with a moderate  heat, being dissolved and
 filtered, the dark gray pasty  oxide left on
 the  filter is to be mixed with  a very little
 solution  of gum-tragacanth,  and the  cloth
 marked with this is to be dipped in a solu-
 tion of potash or soda, mild or caustic, in
 about ten parts of water.
    Among the amusing experiments of the
 art  of chemistry, the exhibition of sympa-
 thetic inks holds a distinguished place. With
 these the writing is invisible, until some re-
 agent gives it opacity.  We shall here men-
 tion a few out of the  great number, that a
 slight acquaintance with chemistry may sug-
 gest to the student.   1. If a weak infusion
 of galls be  used, the writing will be invisi-
 ble  till the paper be moistened with a weak
 solution of sulphate of iron.  It then becomes
 black, because these  ingredients form ink.
  2. If paper be soaked in a weak infusion of
  galls, and dried, a pen dipped in the solution
  of sulphate of iron will write black on that
  paper., but colourless en  any other paper.
3. The diluted solutions of gold and silver
remain colourless upon the  paper,  till ex-
posed to the sun's light, which gives a dark
colour to the oxides, and renders them vi-
sible.  4. Most of the acids, or saline solu-
tions, being diluted, and used to write with,
become  visible  by heating before the fire,
which concentrates them, and assists their
action on the  paper.  5.  Diluted prussiate
of potash affords blue letters when wetted
with the solution of sulphate of iron. 6. The
solution of cobalt in  aqua regia, when di-
luted, affords an ink  which becomes green
when held to the fire, but disappears again
when suffered to cool.  This has been used
in fanciful drawings of trees,  the green
leaves of which appear when warm, and va-
 nish again by cold. If the heat be continued
too  long after the letters appear, it renders
them permanent. 7. If oxide of cobalt be
dissolved in acetic acid, and a  little nitre
 addeel, the solution will exhibit a pale rose
 colour when  heated, which disappears on
 cooling. 8. A solution of equal parts of sul-
 phate of copper and muriate  of ammonia,
 gives a yellow colour when heated, that dis-
 appears when cold.
   Sympathetic inks have been  proposed as
 the instruments of secret correspondence.
 But they are of little use in this respect, be-
 cause the properties change by a few days
 remaining on the paper; most of them have
 more or  less of a  tinge  when thoroughly
 dry; and  none of them  resist  the test of
 heating the paper till it begins to be scorched.
   * Nitrate  of silver for  a surface impreg-
 nated with carbonate  of soda, and muriate
 of gold for one impregnated with protomu-
 riate of tin, form good indelible inks.*
   Insects.  Various important products are
 obtained from  insects.  The chief are,' L
 Cantharides; 2. Millepedes; 3. Cochineal; 4.
  Kermes; 5. Lac; 6.  Silk; 7- Wax.
   Instruments (Chemical.)  See Balance,
  TnLRMOMETEH, LABORATORY.
   * Intestinal Concretions.  For a de-
  scription of such of these as occur in the
  inferior animals, see Bezoar.
   I shall here insert an account of a very cu-
  rious concretion extracted from the rectum
  of  a woman in Perthshire, in the year 1817.
  She is, I believe, still alive. It was sent to
  me by her physician, Dr. Kennedy  of Dun-
  ning.  The following paper was written at
  the time, and an abstract published in a Lon-
  don Medical Journal, in the autumn of the
  same year.
    The form of the concretion is a compress-
  ed cylinder, the length and larger diameter,
  each one inch; the smaller  diameter, three
  quarters of an inch.   In hardness, it is equal
  to  wax, but without its  tenacity.  One of
  the ends, which is polished, and glistening,
  exhibits the appearance of concentric lami-
  nse, formed of circular brown lines, in ay el- 
INT
INT
 low basis.  Its sides have  the lustre, and
 marbleei appearance, of Castile  soap.  Its
 internal stnicture is granular,  approaching
 to crystalline, with radiations from the cen-
 tre to  the circumference, of brown and
 bright yellow lines, possessed  of pearly lus-
 tre.  It is friable  between  the fingers, co-
 vering  them,  on  pressure, with  a  mealy
 powder, of but little unctuosity.
  Its weight  is 167.5 grains.   Specific gra-
 vity ofthe mass seems at first inferior to that
 of distilled water;  for it  floats on it  for a
 little, but it afterwards sinks to the bottom.
 In a solution of muriate of soda, sp. gr.
 1.0135, a fragment of it remains suspended
 in any part of the fluid.  This,  therefore,  is
 its specific gravity.
  Its oelour is strong, but by no means dis-
 agreeable. It is decidedly musky, or more
 precisely that of ambergris.
  Water has  no action on  it, nor does it af-
 fect the purple of litmus.   It remains  solid
 in boiling water.   When it is heated to the
 temperature  of about 400° F.,  it  fuses into
 a black mass, and exhales a copious white
 smoke, in the odour of which, we may re-
 cognize that  of ambergris, mixed with the
 smell of burning fat.   Exposed in a platina
 capsule to a  dull  red heat, it burns with
 much flame  and smoke, leaving no  appre-
 ciable residuum.
  It dissolves rapidly in sulph. ether, form-
 ing an  amber-coloured liquid. When the
 ether  evaporates   away,  white  glistening
 scales, of a micaceous appearance, are left.
  Ten parts  of hot alcohol dissolve one of
 it, but as the alcohol  cools, the greater part
 precipitates in these soft crystalline scales,
 while the surface of the liquid  becomes co-
 vered with  a beautiful iridescent pellicle,
 presenting stellated radiations
  Naphtha, the fixeel and volatile  oils, rea-
 dily act upon it, forming bright yellow solu-
 tions.
  Small fragments of it, exposed on a sand-
 bath, for two days, in a glass capsule, con-
 taining the water of pure potash,  were not
 found to be altered in their size or appear-
 ance. Neither does liquid ammonia, digest-
 ed  on  it, produce  the slightest effect.  In
 these respects,  it possesses more  analogies
 with ambergris, than with any other sub-
 stance I know.   I was hence led to imagine
 that the white smoke which it exhales at a
 moderate heat,  was benzoic acid, which Uiis
 substance is said copiously to contain.
  An alcoholic solution of the concretion
 was therefore added to  water  of ammonia,
when a milky liquid  was produced by the
separation  of the substance, in a finely di-
 vided state.  This mixture was evaporated
to dryness by a gentle heat, in  order to get
rid  of the alcohol and uncombined ammonia.
 Warm water  was then digested on the resi-
 duum,  and the whole poured  on  a  filter.
 The liquid which passed through,  should
have  contained benzoate of ammonia, pro
vided any benzoic acid existed in  the con-
cretion.   It was divided into two  portions.
Into one of these, a few drops of dilute sul-
phuric acid were poured; and the acidulous
fluid was then concentrated by evaporation
in a glass capsule; but on cooling, it afford-
ed no traces of benzoic acid.  An extremely
minute  quantity of benzoate  of ammonia,
treated  in the same  way, for comparison,
gave the characteristic crystals of that acid.
The other portion,  was added  to  a neutral
solution of red muriate of iron, but no pre-
cipitate ensued.  A very small particle  of
crystallized benzoate of ammonia being add-
ed to the same muriate,  speedily gave the
brown precipitate, but produced no change
whatever on solutions, perfectly neutral,  of
the green  muriate  and  sulphate;  a fact  of
consequence to show the state of oxidize-
ment, in which iron exists in a mineral,  or
saline combination,  indicating also an easy
method of separating the two oxides of this
metal.  From the above experiments, we
may infer, with much probability, that the
concretion contains no benzoic acid.
  Nitric acid, sp. gravity 1.300, digested on
it, at a genUe heat,  and  then cooled, con-
verted the substance into bright yellow glo-
bules, denser and less friable than the origi-
nal  matter, and somewhat semi -transparent,
like impure rosin.   There was, however,no
true solution  by the acid; nor was the com-
bustibility in the least impaired by the ope-
ration.
  As  our Institution possesses specimens of
very fragrant  ambergris, said to have been
imported in the genuine state from Persia, I
was desirous to compare their chemical rela-
tions  with those of this morbid concretion.
Two  of the  pieces  of ambergris  differ in
many respects from one another.  The first
is of a light gray colour, with resinous look-
ing points interspersed  through it, and has
a density considerably greater than water.
It is 1.200.  When heated in water to the
temperature of 130°,  it falls down into light
spongy fragments.  The  second  has a spe-
cific gravity of 0.959; it  is darkish brown
on the outside, and light brown within.  In
water heated to the above degree,  it softens
into a viscid substance like treacle.  Both
are  readily dissolved in  warm alcohol, but
the latter yields the richer golden-coloured
solution.  As the alcohol cools, a separa-
tion of brilliant scales is  perceived.  With
ether, naphtha, the fixed and volatile oils, the
phenomena exhibited by ambergris are ab-
solutely the same, as those presented by the
concretion, with these solvents.  The  alco-
holic  solution, mixed  with liquid ammonia,
gives  a similar milky emulsion.
  The lighter specimen of ambergris, exposed
to a gentle heat over  a lamp, in a glass tube
seal d at one end, fuses and evolves a vola-
tile oil in dense vapour, which is condensed 
INT                                  INT
on the upper part of the tube.  A  viscid
substance like tar, remains at the bottom.
The oil resembles the  succinic, and  has,
like it, a disagreeable empyreumatic odour.
The denser ambergris,  being subjected to
heat in like circumstances, fuses less  rea-
dily and completely, emits the  same vola-
tile empyreumatic oil, accompanied  with
crystalline needles,  decidedly acidulous.
These are either the  benzoic  or succinic
acid.  They  precipitate  peroxide of iron
from the neutral red muriate.   The smell
of the accompanying oil, is certainly that
of amber; but 1 have hitherto obtained too
small quantities of the acid, to be able to
determine to which of the two it belongs.
The following experiments were made with
this view. My first object was to discover
a good criterion for discriminating benzoic
from succinic acid.  In operating necessa-
rily on small quantities, the distinction be-
comes peculiarly difficult. Both are vola-
 tile, crystallizable, and fall down with per-
oxide of  iron,  from saline solutions of this
 metal.  After many trials I finally fell on
the following  plan, which answers  very
well, even with pretty minute portions.  I
saturated each acid with ammonia; evapo-
rated to a dry crystalline mass, by a gentle
heat. Into a  small glass tube, sealed atone
end, 1 introduced a  portion  of the ben-
 zoate.  The tube was recurved.  I expo-
 sed the bottom where the 6alt was placed,
 to the heat of  a lamp, but very cautiously.
 Pungent ammoniacal gas was  exhaled, and
 the water of crystallization, that distilled
 over, was found strongly impregnated with
 ammonia.  To avoid  all fallacy in this re-
 sult, I slightly supersaturated the ammonia
 beforehand,  with the  acid. In the middle
 of the tube, pure benzoic acid was found,
 in acicular crystals.  The succinate of am-
 monia, on the  contrary,  sublimes  without
 decomposition.
    I now  took a few grains of the dense am-
 bergris,  digested with alcohol, added wa-
 ter of ammonia, boiled,  filtered, and eva-
 porated to dryness.   The quantity of sa-
 line matter  obtained, was, however, too
 minute, even for the above mode of apply-
 ing an analytical criterion, with satisfac-
 tion; and being unwilling to consume more
 than a few grains of a  specimen, belong-
 ing to a public establishment, I preferred
 waiting till some future opportunity might
 occur of examining genuine ambergris.
    From  the lighter, and by its outward ap-
 pearance, more characteristic specimen, of
 ambergris, I could not obtain even a trace
 of benzoic acid, though 1 modified the tem-
 perature for sublimation, and other circum-
 stances, in every way  1 could think of. The
 oil that rose would not  redden the most
 delicate litmus paper.
    In open capsules, fragments of the am-
    Vol.. 11.
bergris, being exposed to pretty strong
heat, exhaled the copious subfcctid smoke;
and afterwards burned with the yellow
flame, exhibited by the concretion.  Frag-
ments of the concretions, exposed to heat
in a glass tube, fused, evolved the  heavy
smoke, which condensed into a viscid em-
pyreumatic smelling oil, and in every res-
pect comported itself  like the light am-
bergris.
  1 therefore must infer it to be a modifi-
cation of ambergris.  It differs decidedly
from the adipocere of dead bodies,  which
forms an emulsion with cold water,  is fu-
sible in boiling water, gives  a soap, with
evolution of ammonia, when treated with
potash, and yields a clear solution,  when
gently heated with  liquid ammonia.   It
resembles, however, in many respects, the
chdesterine of biliary calculi; and I have
no  doubt that cholesterine from altered
bile, is the true origin of ambergris in the
whale,  as  well as of this morbid concre-
tion.
  The concretion is almost wholly soluble
in hot alcohol; while only one-third  of adi-
pocere dissolves in  that menstruum at the
boiling point.
  From ordinary fatty matter it is entirely
distinguishable, by  its solubility  in ether
and alcohol,  its refusing to combine with
alkalis, and the high temperature required
for its fusion.
  With regard to their place of formation
in the animal system, ambergris  and this
morbid concretion agree. • They  are both
generated in the rectum, or greater intes-
tines.    The physeter macrocephalus  of
Linnaeus  is  the  species of  whale which
affords ambergris.   In the examination of
Captain Coffin before the Privy-Council in
 1791, he stated, that he found 362  ounces
of ambergris in the intestines of  a  female
 whale, struck off the coast of Guinea; part
of  it was voided from the rectum on cut-
ting up the blubber, and the remainder was
 within the intestinal canal.
   The whales  that contain ambergris are
 said to be always lean and sickly, yield but
 very little  oil,  and seem almost  torpid.
 Hence when a spermaceti whale has this
 appearance, and does not emit feces  on
 being harpooned, the  fishers generally ex-
 pect to find ambergris within it.  Whether
 it be the cause or the effect of disease, is
 problematical, though the latter seems the
 more rational conjecture.  It may  in suc-
 cession be both.  The above  remarkable
 fact of the sex of the whale, may  lead to
 an inquiry, whether this morbid produc-
 tion, found also in the human subject,  be
 peculiar to females, and connected with
 lactation.
   In the  second volume of Dr. Monro's
 Outlines of the Anatomy of the  Human
                       15 
IOD                                  IOD
Body in its sound and diseased state, we
have the analysis of several alvine concre-
tions by Dr. Thomas Thomson.  The re-
sults, obtained  by this eminent chemist,
show, that the specimens which he examin-
ed, were of a totally  different nature from
the preceding concretion.*
  * Inulin.   From  the root of the inula
helenium, or elecampane, Rose  first ex-
tracted  the peculiar vegetable principle,
called inulin.   M. Funke has  since given
the following as the analysis of elecampane
root:—
      A crystallizable volatile oil,
      Inulin,
      Extractive,
      Acetic  acid,
      A crystallizable resin,
      Gluten,
      A fibrous matter  (ligneous).*
  •Iodine. A peculiar or undecompound-
ed  principle.   The  investigation  of this
singular substance will always be  regard-
ed  as a great era in chemistry.  It was
then that chemical philosophers first felt
the necessity of abandoning  Lavoisier's
partial and incorrect hypothesis of oxyge-
nation, and of embracing the  sound and
comprehensive doctrines of Sir  H.  Davy
on chemical theory,  first promulgated  in
his masterly researches on Chlorine.
  Ioeline was accidentally  discovered,  in
1812, by M. de Courtois, a manufacturer of
saltpetre at Paris. In his processes for pro-
curing soda from the ashes of sea-weeds,
he  found the metallic vessels much cor-
roded; and in searching for the  cause  of
the corrosion, he made this important dis-
covery.  But  for this circumstance, nearly
accidental, one of the most curious of sub-
stances might have remained for ages un-
known, since nature has not distributed it,
in  either  a  simple  or compound  state,
through her  different kingdoms, but has
confined it, to what the  Roman satirist
considers as the most worthless of things,
the vile sea-weed.
   Iodine derived its first illustration from
MM. Clement and Desormes,  names asso-
ciated  always with  sound research.   In
their memoir, read at a meeting of the In-
stitute, these able chemists described  its
principal properties.  They stated its sp.
gr. to be about 4; that it becomes a violet-
coloured gas  at a temperature below that
of boiling water; whence its name,  Ta/nc;
like a violet, was derived; that it combines
with the metals, and with phosphorus and
sulphur, and likewise with the alkalis and
metallic oxides; that it forms  a detonating
 compound with ammonia; that it is soluble
 in alcohol, and still more soluble in ether;
 and that, by its action upon phosphorus and
 upon hydrogen, a substance  having  the
 characters of muriatic acid is formed.  In
this communication they offered no deci-
ded opinion respecting its nature.
  In 1813 Sir H. Davy happened to be on
a visit to Paris, receiving, amid the politi-
cal convulsions of France, the tranquil ho-
mage due to his genius.  " When M. Cle-
ment showed iodine to  me,  he believed
that the hydriodic acid was muriatic acid;
and  M. Gay-Lussac, after his early experi-
ments, made originally with M. Clement,
formed the same opinion,  and  maintained
it, when I first stated to him my belief,
that it was a new and peculiar  acid, and
that iodine  was a substance  analogous  in
its chemical  relations to  chlorine."—Sir
H. Davy on the Analogies between the unde-
compounded substances; Journal of Science
and the Arts, vol. i. p. 284.
   We see therefore with what intuitive sa-
gacity the English philosopher penetrated
the mystery which hung at  first over io-
dine.  Its full examination,  in its  multi-
plied  relations  to simple and  compound
bodies, was immediately entered on with
equal ardour by him, and M. Gay-Lussac.
Of the relative  merits of the researches,
and importance  of the  results, of these
pre-eminent chemists, it is not  for me  to
become an arbiter.  I shall content myself
with offering a  methodical view of the
facts brought to light on iodine  and the
iodides, referring  for its  other combina-
tions to what I have already  stated on the
hydriodic and iodic acids.
   Iodine has been found in  the following
sea-weeds, the algx aquatics of Linnaeus:—
Fucus cartilagineus;  Fucus palmatus,
       membranaceus,       filum,
       filamentosus,        digitatus,
       rubens,              saccharinus,
       nodosus,       Ulva umbilicalis,
       serratus,             pavonia,
        siliquosus,           linza, and in
                            sponge.
   Dr. Fyfe has shown, in an ingenious  pa-
 per, published  in the first volume of the
 Edin. Phil. Journal, that on adding sulphu-
 ric acid to a concentrated viscid infusion of
 these algx in hot water, the vapour of io-
 dine is exhaled.
   But it is from the incinerated sea-weed,
 or kelp, that iodine in  quantities is to be
 obtained. Dr. Wollaston first communica-
 ted a precise  formula for  extracting  it.
 Dissolve the soluble part of kelp in water.
 Concentrate the liquid by evaporation, and
 separate all the crystals that can be obtain-
 ed.   Pour the remaining liquid  into a clean
 vessel, and mix with it an excess of sulphu-
 ric  acid.  Boil this liquid for  some time.
 Sulphur is precipitated, and muriatic acid
 driven off. Decant off the clear liquid, and
 strain it through wool.  Put it  into a small
 flask, and mix it with as much black oxide
 of manganese, as used before of sulphuric
 acid.   Apply to the top of the flask a glass 
IOD
IOD
tube, shut at one end. Then heat the mix-
ture in the flask. The iodine sublimes into
the glass tube. None can be obtained from
sea-water.
  In  repeating this process  with care, I
obtained from similar quantities of kelp
such  variable products  of iodine, that I
was induced to institute a series of expe-
riments in  1814, for discovering the causes
of these anomalies, and for procuring  io-
dine at an easier rate.  The result, which
was  successful, I communicated  to  the
world in the 50th volume  of the Philoso-
phical Magazine. Instead of procuring this
interesting element in only a few grains, I
have  been able to extract ounces  at a time,
and at a moderate expense.   I shall here
transcribe the outlines of my method.
  As several of the Scotch soap manufac-
turers use scarcely any other alkaline mat-
ter for their hard soaps except kelp, it oc-
curred to me that in some of their residu-
um s, a substance might be found rich in
iodine.   Accordingly,  after some investi-
gation, I found a brown liquid, of an oily
consistence, from which I expected to pro-
cure what I wanted, and I therefore insti-
tuted a series of experiments  on the best
mode of extraction.
  The specific gravity of this liquid, as ob-
tained at different times, is pretty uniform-
ly  1.374.  It  converts  vegetable blues to
green, thus indicating free alkali.  Of this
the manufacturer  is aware, for he  returns
the liquid occasionally into his kelp leys.
Its boiling  point is 233° F. Eight ounces
apothecaries* measure  require  precisely
one measured ounce of sulphuric acid  for
their neutralization.  Supposing this quan-
tity of acid combined with soda, it would
indicate one part of pure soda in eleven by
weight of the liquid. But the chief part of
the alkali  is not uncombined; for an  im-
 mense  quantity of sulphurous acid, and a
 little sulphuretted hydrogen  gas,  escape
 during the affusion of the sulphuric acid.
   " 100 grains of  the liquid  yield 3.8 cu-
 bic inches of gas, chiefly sulphurous acid,
 and  sulphur is  at the same time deposited.
 From this last circumstance one would ex-
 pect a greater proportion of sulphuretted
 hydrogen; but the disengaged gas posses-
 ses  the peculiar smell and  pungency ot
 burning sulphur, blanches the petals ofthe
 red rose, but shows scarcely any action on
 paper dipped in  saturnine solutions.  On
 the  instant of decomposition of  the  sul-
 phite and hydroguretted sulphuret of soda
 existing in the liquid,  the nascent sulphu-
 rous acid of the  former may be supposed
 to decompose the nascent sulphuretted hy-
 drogen ofthe latter; their  atoms  of oxy-
 jren and hydrogen uniting, with precipita-
 rion of the sulphur. I can in no other way
 account for the very copious  separation ot
  sulphur, while very little sulphuretted hy-
drogen appears." I now find the liquid to
contain hyposulphite of soda.
  From 8 liquid ounces = 11  by weight,
213 grains of sulphur  are  obtained.  The
saturated liquid has a specific gravity of
1.443, a bright yellow colour, and does not
change the purple colour of infusion of red
cabbage.
  Having described the substance which I
used, I shall now state, in a few words, the
best method of taking the iodine out of
it:—
  " The brown iodic liquid of the soap-
boiler, was heated to about  230Q F. pour-
ed into a large stone-ware basin, of which
it filled about one-half, and saturated by the
addition of the suitable quantity of sulphu-
ric acid as above stated.   It is advantage-
ous to dilute the acid previously, with ita
own bulk of water.§  On cooling the mix-
ture, a large quantity of saline crystals  is
found adhering to the sides and bottom of
the vessel.  These are chiefly, sulphate of
soda, with a very little sulphate of potash
and  a few beautiful  oblong  rhomboidal
plates  of hydriodate of soda.  Sulphur is
mixed with these crystals.
  " Filter  the  above  cold  liquid  through
woollen  cloth.   To every  12 oz. apotheca-
ries' measure, add 1000  grains of black
oxide of manganese in powder.  Put this
mixture into a glass globe, or large matrass
with a wide neck, over which a glass globe
is inverted, and apply heat with a charcoal
chauffer.  The less diffusive flame of  a
lamp,  is apt  to crack the bottom of the
matrass; particularly,  if a  large quantity
of materials be employed.  To prevent the
heat from acting on the globular receiver,
a thin  disc of wood, having a round hole
in its centre, is placed over the shoulder
of the matrass.
   " Iodine  now sublimes  very copiously,,
and is readily condensed in the upper ves-_
sel.  As soon  as this becomes warm, ano-
ther is to be put in its place;  and  thus the
two may be applied in rotation, as long as
 the violet vapour rises.
   " From the above quantity of liquid, by
 this treatment, I  obtain  from 180 to 200
 grains of iodine, perfectly pure. It is with-
 drawn from the globes, most conveniently
 by a little water,  which  dissolves iodine
 very sparingly, as  is well known.  It may
 be purified by a second sublimation from
 lime.
   " If the manganese be  increased much
 beyond the above proportion, the product
 of iodine  is  greatly decreased.   If thrice
 the quantity be used, for example,  a furi-
  ous effervescence takes  place, nearly  the
  $ When concentrated acid is added, the
effervescence is very violent; the  liquid
reddens wherever the acid falls, and a lit-
tle purple vapour of iodine rises. 
IOD                                   IOD
whole  mixture is  thrown out of the ma-
trass, with a  kind of explosive violence,
and hardly any  iodine is  procured, even
though the materials should be saved, by
the relatively  large capacity of the vessel
that contains them.  If, on the other hand,
one-half of the prescribed quantity of man-
ganese be used, much hydriodic acid rises
along with the iodine, and washes it perpe-
tually down the  sides of the balloon.  Or
if, during the  proper and successful  subli-
mation of iodine, the weight of manganese
be  doubled, the violet vapours instantly
cease.  Nor will sugar or starch restore to
the mixture,  the  power  of  exhaling the
iodine.
  " The  same interruption of the process
is occasioned by using an excess of sul-
phuric acid.   For, if to the mixture of 12
oz. of saturated liquid, with 1000 or 1100
grains manganese, an additional half ounce
measure of sulphuric acid be poured in, the
violet vapour  disappears,  and the sublima-
tion of iodine  is at an end. Quicklime now
added so as to saturate the excess of acid,
will not restore the production of iodine.
  " The   best subliming  temperature  is
232° Fahr.
  " Iodine, in open vessels,  readily evapo-
rates  at much lower temperatures, even at
the usual atmospheric heats.  When it is
spread thin on a plate of glass,  if the eye
be placed in the same plane, the violet va-
pour  becomes very obvious at the tempe-
rature of 100° F. ' If left in the open air,
it will speedily evaporate altogether away,
even at 50 or  60°.  When kept in a phial
stopped  with  a common  cork, the  iodine
also disappears, while the  cork will become
friable in its  texture, and of a brownish-
yellow colour.
  "240 grains of nitric acid, specific grav.
1.490, saturate 1000 grains of  the  brown
liquid.  Sulphurous acid is abundantly ex-
haled as before.   After filtration, a bright
golden-coloured liquid is obtained. On ad-
ding to this liquid a little manganese, io-
dine sublimes; but the quantity procurable
in this way, seems to be proportionally less
than by  the sulphuric acid."
   I have elescribed a new form of appara-
tus, for sublimation, in the above paper, by
which beautiful crystals may easily be pro-
cured, without risk of injuring their form.
   Iodine is a solid, of a grayish-black co-
lour and metallic lustre. It is often in scales
similar  to those  of micaceous iron ore,
sometimes in rhomboidal plates, very large
anel very brilliant. It has been obtained in
elongated octohedrons, nearly half an inch
in  length; the axes of which were  shown
by Dr. Wollaston  to be to  each other, as
the numbers  2, 3, and 4, at least so nearly,
that in a body so volacile, it is scarcely pos-
sible to  detect an  error in this estimate, by
the reflective goniometer,   its fracture is
Iamellated, and it is soft and friable to the
touch. Its taste is very acrid, though it be
very  sparingly soluble  in  water.  It is a
deadly poison.  It gives a deep brown stain
to the skin, which soon vanishes by evapo-
ration.  In odour, and power of destroying
vegetable colours, it resembles very  dilute
aqueous chlorine. The sp. gr. of iodine at
624° is 4.948.  It dissolves in 7000 parts of
water. The solution is of an orange-yellow
colour,  and in small quantity tinges raw
starch of a purple hue, which vanishes on
heating it.   It  melts, according to M. Gay-
Lussac, at 227° F. and is volatilized  under
the common pressure of the atmosphere,
at the temperature of 350°.  By my expe-
riments, it evaporates pretty quickly at or-
dinary  temperatures.  Boiling water aids
its sublimation, as  is shown in the  above
process of extraction.  The sp.  gr. of its
violet vapour is 8.678.  It is a non-conduc-
tor of electricity.  When the voltaic chain
is  interrupted  by  a  small  fragment of
it, the decomposition  of water  instantly
ceases.
   Iodine  is incombustible, but with azote
it forms a curious  detonating compound;
and in combining with several bodies, the
intensity  of mutual action is such as to
produce the phenomena of combustion. Its
combinations  with  oxygen  and chlorine,
have been already described,  under iodic
and chloriodic acids.
   With a  view of determining whether it
was a simple or compound form of matter,
Sir II. Daw  exposed it to the action ofthe
highly inflammable  metals.  When  its va-
pour is passed  over potassium  heated in
a glass tube, inflammation takes place, and
the  potassium burns slowly  with  a pale
 blue light.  There  was no gas disengaged
 when the experiment  was repeated in a
 mercurial apparatus.  The iodide  of pot-
 assium is  white, fusible at a red heat, and
 soluble in water.  It has  a peculiar acrid
 taste.  When  acted on by sulphuric acid,
 it effervesces, and iodine appears. It is
 evident, that in  this experiment there bad
 been no decomposition; the result depend-
 ing merely  on the combination  of iodine
 with potassium. By passing the vapour of
 iodine over dry red-hot potash, formed from
 potassium, oxygen  is  expelled, and the
 above iodide results.  Hence we see, that
 at the temperature  of ignition, the affinity
 between iodine and potassium, is superior
 to that of the latter for  oxygen. But iodine
 in its turn is  displaced by chlorine, at a
 moderate  heat,  and if the latter be in ex-
 cess, chloriodic  acid is formed.  M. Gay-
 Lussac passed vapour  of iodine in a red
 heat over melted subcarbonate  of  potash;
 and he obtained  carbonic acid and oxygen
 gases, in the proportions of two  in volume
 of the  first, and one of the  second, pre-
 cisely those  which  exist in the salt. 
IOD                                  IOD
  The oxide of sodium, and the subcarbo-
nate of soda, are also  completely decom-
posed by iodine.  From these experiments
it would seem, that this substance  ought
to disengage oxygen, from most ofthe ox-
ides; but this happens only in a small num-
ber of cases.   The protoxides of lead and
bismuth are the only oxides not reducible
bv mere heat, with which it exhibited that
power.  Barytes, strontian, anel lime com-
bine with iodine, without giving out oxy-
gen gas, and the oxides of zinc and iron
undergo no alteration in this respect.  From
these facts we must conclude, that the de-
composition  of  the oxides  by iodine de-
pends less on the condensed state of the
oxygen, than upon the affinity of the metal
for iodine.  Except barytes, strontian, and
lime, no oxide can remain in combination
with iodine at a red heat  For a more par-
ticular account of some iodides, see Acid
(Hydriodic); the compounds of  which,
in the liquid  or moist state, are hydrio-
dates, but change, on drying, into iodides,
in the same way as the muriates become
chlorides.
   From the proportion of the constituents
in hydriodic acid, 15.5 has been deduced,
as the prime equivalent of iodine.
   M. Gay-Lussac says, " Sulphate of potash
was not altered by iodine;  but, what may
appear astonishing, 1 obtained oxygen with
the fluate of potash, and the glass  tube in
 which the  operation  was  conducted was
 corroded.  On examining  the circumstan-
 ces of the experiment, I ascertained that
 the fluate became alkaline when melted in
 a platinum  crucible.   This happened to
 the fluate over which I passed iodine.  It
 appears then that the iodine acts upon the
 excess of alkali, and decomposes it. The
 heat produced disengages anew portion of
 fluoric acid  or its radical, which corrodes
 the glass; and thus by degrees the fluate
 is  entirely  decomposed."  These facts
 seem to give countenance to the opinion,
 that the fluoric is an oxygen acid; and that
 the salt called fluate of potash is not a flu-
 oride of potassium. See Acid (Fluoric).
   Iodine forms with sulphur a feeble com-
 pound, of a grayish-black colour, radiated
 like sulphuret of antimony. When it is
 distilled with water, iodine separates.
   Iodine  and  phosphorus  combine with
 great  rapidity  at  common  temperatures,
 producing heat without light.   From  the
 presence of a little moisture, small quanti-
 ties of hydriodic acid gas are exhaled.
    Oxygen expels iodine from both sulphur
 and phosphorus.
    " Hydrogen, whether dry or moist,  did
 not seem," says M. Gay-Lussac, " to have
 any action on iodine at the ordinary tempe-
 rature; but  if, as was done by M. Clement,
 in an experiment at which 1 was  present,
 we expose a mixture of hydrogen and io-
dine to a red heat in a tube, they unite to-
gether,  and hydriodic  acid  is produced,
which  gives  a reddish-brown  colour  to
water."   Sir H. Davy, with his character-
istic ingenuity, threw  the violet-coloured
gas upon the flame  of  hydrogen,  when it
seemed to support its combustion. He also
formed  a compound of iodine with hydro-
gen, by heating to redness the two bodies
in a glass tube.  See Acid (Hydriodic).
   Charcoal has no action upon iodine,  ei-
ther at  a high or low temperature.   Seve-
ral of the common  metals, on the contrary,
as zinc, iron, tin, mercury,  attack it rea-
dilv, even at a low  temperature, provided
they be in a divided state.   Though  these
combinations take place rapidly, they pro-
duce but little  heat,  and but.  rarely any
light.
   The  compound of iodine  and zinc, or
iodide of zinc, is white.   It melts readily,
and is sublimed in the state of fine acicular
four-sided prisms.  It is very soluble in
water,  and rapidly deliquesces  in the  air.
It dissolves in water, without the evolution
of any  gas.  The solution is slightly acid,
and does  not  crystallize.   The  alkalis
precipitate  from it white oxide of zinc;
while  concentrated sulphuric acid  disen-
 gages hydriodic acid and iodine, because
 sulphurous acid is produced.  The solu-
 tion is a hydriodate of oxide of zinc.  When
 iodine and zinc are made to act on each
 other  under water in vessels hermetically
 sealed, on the application of a Slight heat,
 the water assumes a  deep  reddish-brown
 colour, because, as soon as  hydriodic acid
 is produced, it dissolves iodine in abun-
 dance.  But by degrees, the zinc, supposed
 to be in excess,  combines with  the  whole
 iodine, and the solution becomes colourless
 like water.
   Iron is acted on by iodine in  the same
 way  as zinc;  and a brown iodide results,
 which  is fusible at a red heat.  It dissolves
 in water,  forming a light green solution,
 like  that  of muriate  of iron.   When the
 dry iodide was heated, by Sir H. Davy, in
 a small retort containing pure ammoniacal
 gas, it combined  with  the ammonia, and
 formed a compound which volatilized with-
 out leaving any oxide.
    The iodide of tin is very fusible.  When
 in powder, its colour  is  a dirty orange-yel-
 low, not unlike that of glass of antimony.
  When put into a considerable quantity of
 water, it is completely  decomposed.  Hy-
 driodic acid is  formed,  which remains in
  solution in the water, and the oxide of tin
 precipitates in white  flocculi.  If the quan-
  tity of water be small, the acid being more
  concentrated, retains a portion of oxide of
  tin, and forms a silky orange-coloured salt,
  which may be almost entirely decomposed
  by water.  Iodine and tin act very well on
  each other, in water of the temperature of 
IOD                                   IRI
"212°.  By employing an excess of tin, we
may obtain pure hydriodic acid, or at ieast
an acid containing only traces ofthe metal.
The tin must be in considerable  quantity,
because  the  oxide which  precipitates on
its surface, diminishes very much its ac-
tion on iodine.
   Antimony presents, with iodine, the same
phenomena as tin; so that we might employ
either for the preparation of hydriodic acid,
if we were not acquainted with preferable
methods.
   The iodides  of lead, copper,  bismuth,
silver, and mercury, are insoluble in water,
while the iodides of the very oxidizable
metals are soluble in that  liquid.   If we
mix a hydriodate with the  metallic solu-
tions, all the metals which  do not decom-
pose  water  will give precipitates,  while
those which  decompose that liquid, will
give none.   This is at least the case with
the above mentioned  metals.
   There are two iodides of mercury; the
one yellow, the other  red; both are fusible
and volatile.  The yellow or protiodide,con-
tains one-half less iodine than the deutio-
dide.   The latter, when crystallized, is a
bright crimson.   In general there ought
to be for each metal as many iodides, as
there are oxides and  chlorides.  All the
iodides are decomposed by  concentrated
sulphuric and nitric acids.   The  metal  is
converted into an oxide, and iodine is dis-
engaged.  They are likewise decomposed
by oxygen at a  red heat, if we except the
iodides of potassium, sodium, lead, and
bismuth   Chlorine likewise separates io-
dine from all the iodides; but iodine, on the
other hand,  decomposes  most of the sul-
phurets and phosphurets.
  When iodine and oxides act upon each
other in contact  with water, very different
results take  place, from those above de-
scribed.  The water is decomposed; its hy-
drogen unites with iodine, to form  hydri-
odic acid; while  its oxygen, on the  other
band,  produces  with  iodine, iodic acid.
All the oxides, however, do not  give the
same results.  We obtain  them only with
potash, soda, barytes, strontian, lime, and
magnesia.  The  oxide of zinc, precipitated
by ammonia from its solution in sulphuric
acid,  and well washed, gives no  trace of
iodate and hydrioelate.
  We shall treat of the compound  of io-
dine and azote under the article \ itrocen.
   From all the above  recited facts, we are
warranted in concluding iodine  to be an
undecompounded  body.   In its specific gra-
vity, lustre,  and magnitude of its prime
equivalent, it resembles the metals; but  in
all its chemical  agencies,  it  is analogous
to oxygen and chlorine.  It is a  non-con-
ductor of electricity, and possesses, like
these two bodies, the negative  electrical
energy with regard to metals, inflammable
 and alkaline substances; and hence, when
 combined with these substances in aqueous
 solution, and electrized in the  voltaic  tir-
 cuit, it separates at the positive surface.
 But it has a positive energy  with respect
 to chlorine; for  when united to  chlorine,
 in the  chloriodic acid, it separates at  the
 negative surface.  This likewise corres-
 ponds  with their relative attractive ener-
 gy, since chlorine expels iodine from all its
 combinations.  Iodine dissolves in carburet
 of sulphur, giving, in very minute quanti-
 ties, a fine  amethystine tint to the liquid.
  Iodide of mercury has been proposed for
 a pigment; in other respects, iodine has not
 been applied to any purpose  of common
 life. M. Orfila swallowed 6 grains of iodine;
 and  was immediately  affected with heat,
 constriction of  the throat, nausea, eructa-
 tion, salivation,  and cardialgia.  In ten mi-
 nutes he had copious bilious vomitings,  and
 slight colic pains.  His pulse rose from 70
 to about 90 beats in the minute.  By swal-
 lowing  large quantities of mucilage,  and
 emollient clysters, he recovered, and  felt
 nothing next day but slight fatigue. About
 70 or 80 grains proved a fatal dose to dogs.
 They usually died  on  the fourth or fifth
 day.*
  Iridium.  Mr. Tennant, on examining
 the  black  powder left after  dissolving
 platina, which  from its appearance had
 been supposed to consist chiefly  of plum-
 bago, found it contained two distinct me-
 tals, never before noticed, which he  has
 named iridium and osmium.  The former
 of these was observed soon after by Descos-
 tils, and by Vauquelin.
  To analyze the black powder, Mr. Ten-
 nant put it into  a silver crucible, with a
 large proportion of pure  dry soda,  and
 kept it in a red heat for some  time. The
 alkali being then dissolved in water, it had
 acquired a deep orange or brownish-yellow
 colour,  but much of the powder remained
 undissolved.  This, digested  in  muriatic
 acid, gave a dark blue solution, which after-
 wards became of a dusky olive-green;  and
 finally, by continuing the  heat, of a deep
 red.  The residuum being treated  as  be-
 fore with alkali, and so on alternately,  the
 whole  appeared capable  of solution.  As
 some silex continued to be taken up by the
 alkali, till the whole of the metal was dis-
 solved, it seems  to  have been  chemically
 combined  with  it.   The alkaline solution
 contains oxide  of osmium, with a  small
proportion  of iridium,  which separates
 spontaneously in dark-coloured thin flakes
 by keeping it some weeks.
  The acid solution contains likewise both
the metals, but chiefly iridium.  By slow
 evaporation, it affords an imperfectly crys-
 tallized mass; which, being dried on blot-
ting-paper, and dissolved  in  water, gives
by evaporation distinct octohedral crystals. 
IEI                                   IRO
These crystals, dissolved in water, produce
a deep red solution, inclining to  orange,
Infusion of galls occasions no precipitate.
but  instantly  renders the solution almost
colourless.  Muriate of tin, carbonate of
soda, and  prussiate  of potash, produce
nearly the same  effect.  Ammonia  preci-
pitates the oxide, but, possibly from being
in excess, retains  a part in solution, ac-
quiring a purple colour.  The fixed alkalis
precipitate the greater part of the  oxide,
t»ut retain a part in solution, this becoming
yellow.  All the  metals that Mr. Tennant
tried, except gold and platina, produced a
dark or black precipitate from the muriatic
solution, and left it colourless.
  The iridium may be obtained pure, by
exposing  the  octohedral  crystals to heat,
which expels the oxygen and muriatic acid.
It was white,  and could not be mdted by
any heat Mr. Tennant could employ. It
did  not combine with sulphur,  or with
arsenic.  Lead unites with it easily, but is
separated by cupellation, leaving the iridi-
um  on the cupel as a coarse black powder.
Copper forms with  it a very malleable al-
loy, which, after cupellation, with the ad-
dition of lead, leaves a small proportion of
the  iridium, but much less than in the pre-
ceding instance.  Silver  forms with it a
perfectly malleable compound, the surface
of which is tarnished merely by cupella-
tion; yet the iridium appears to be diffused
through it in fine powder only.   Gold re-
 mains  malleable, and little altered in co-
lour, though alloyed  with a considerable
proportion; nor is it separable either by
 cupellation or quartation.  If the gold or
 silver be dissolved, the iridium is left as a
 black powder.
   The French chemists observed, that this
 new metal gave a red colour to the triple
 salt of platina and sal ammoniac, was not
 altered by muriate of tin, and was precipi-
 tated of a dark  brown  by caustic alkali.
 Vauquelin added, that it was precipitated
 by galls, and by  prussiate of potash; but
 Mr. Tennant ascribes this to some impu-
 rity.
   Mr. Tennant gave it the name of indium,
 from the striking variety of colours  it af-
 fords while dissolving in muriatic acid.
   Dr. Wollaston  has observed, that among
 the grains of crude platina, there are some
 scarcely distinguishable  from the rest but
 by  their insolubility in nitro-muriatic acid.
 They are harder, however, when tried by
 the file; not in the least malleable; and of
 the specific  gravity of 19.5.  These ap-
 peared to him to be an ore, consisting en-
 tirely of two new metals.
    * Vauquelin has since succeeded in form-
 ing sulphuret of iridium, by heating a mix-
 ture  of ammonia-muriate  of iridium and
 sulphur.  It is a black powder consisting
 of  100 iridium -f  33.3  sulphur;  whence,
supposing it a neutral compound, the prime
equivalent of iridium would be 6.0.  The
same chemist has also alloyed iridium with
lead, copper, and tin.   They are all malle-
able;  and  considerably hardened by the
presence of the iridium.*
  Iron is a metal of a bluish-white colour,
of considerable hardness  and elasticity;
very malleable, and exceedingly tenacious
and ductile.  This metal is easily oxidized.
A piece of iron wire, immersed in a jar of
oxygen gas, being ignited at one end, will
be  entirely consumed  by the successive
combustion of its parts. It requires a very
intense heat to fuse it;  on which account
it can only be brought into the shape of
tools  and  utensils  by  hammering.  This
high degree  of infusibility would deprive
it of the most valuable property of metals,
namely, the uniting of smaller masses into
one, if it did not possess  another singular
and advantageous property, which is  found
in no other metal except  platina;  namely,
that of welding.  In a white heat, iron ap-
pears  as if covered with a kind bf varnish;
and in this state, if two pieces be applied
together, they will adhere, and may be per-
fectly united by forging.
   When iron is exposed  to the  action of
moist air or water, it  acquires weight by
gradual oxidation, and hydrogen gas es-
capes: this is a very slow operation.  But
if  the steam of  water be made to pass
through a red-hot gun  barrel, or through
 an ignited copper or glass tube, containing
 iron wire, the iron becomes converted into
 an oxide,  while hydrogen gas passes out
 at the other end of the barrel.  By the ac-
 tion of stronger heat this becomes  a red-
 dish-brown oxide.  The yellow rust, form-
 ed when iron is long exposed to damp air,
 is not a simple oxide, as  it contains a por-
 tion of carbonic acid.
   The concentrated sulphuric acid scarcely
 acts on iron, unless it is boiling.  If the
 acid  be diluted with two or three parts  of
 water, it dissolves iron readily, without the
 assistance of heat.  During this  solution,
 hydrogen gas escapes in  large quantities.
   The green sulphate of  iron is much more
 soluble in hot than cold  water; and there-
 fore crystallizes by cooling, as well as  by
 evaporation.  The crystals are efflorescent
 and fall into a white powder by exposure
 to a dry air, the iron  becoming more oxi-
 dized than before.  A solution of sulphate
 of iron, exposed  to the  air,  imbibes  oxy-
 gen;  and  a portion  of the  iron,  becoming
 peroxidized, falls to the  bottom.
    Sulphate of iron is not made in the di-
  rect way, because it can be obtained at less
  charge from the decomposition of  martial
  pyrites.   It exists in two states,  one con-
 taining oxide of iron, with 0.22 of oxygen,
 which is of a pale green,  not altered  by
 gallic acid, and giving a white precipitate 
IRO                                   IRO
with prussiate of potash.  The  other, in
which the iron is combined with  0.30 of
oxygen, is red, not crystallizable, and gives
a black precipitate with gallic acid, and a
blue with prussiate of potash.  In the com-
mon sulphate, these two are  often mixed
in various proportions.
  Sulphate of iron is decomposed by alka-
lis and by lime.  Caustic fixed alkali  pre-
cipitates the  iron in  deep green  flocks,
which  are dissolved  by  the  addition of
more alkali, and form a red tincture.
  Vegetable  astringent matters, such as
nut-galls, the husks of  nuts, logwood, tea,
&c. which contain tannin and  gallic acid,
precipitate a fine  black fecula  from sul-
phate of iron, which  remains  suspended
for a considerable time in the fluid, by the
addition of gum-arabic.  This fluid is well
known by the name of  ink.  See Ink.
  The beautiful pigment,  well  known in
the arts by the name of prussian  blue, is
likewise a precipitate afforded by sulphate
of iron.
  Concentrated nitric acid acts very strong-
ly upon iron filings, much nitrous gas being
disengaged at the same time. The solution
is of a reddish-brown, and deposites the ox-
ide of iron after a  certain  time; more es-
pecially if the vessel be left exposed to the
air.  A  diluted  nitric  acid affords a more
permanent solution of iron of a  greenish
colour, or sometimes of a yellow colour.
Neither of the solutions  affords crystals,
but both deposite the oxide of iron by boil-
ing, at the  same time that the  fluid as-
sumes a gelatinous appearance.
   Diluted muriatic acid rapidly  dissolves
iron at the same time that a large  quantity
of hydrogen is  disengaged,  and the mix-
ture becomes hot.
   If iron filings be triturated with muriate
of ammonia, moistening the mixture; then
drying, powdering, and again triturating;
and lastly subliming with  a  heat quickly
raised; yellow or orange-coloured flowers
will rise, consisting of  a mixture of muri-
ate of ammonia, with more or less muriate
of iron.  These, which were called flowers
of steel, and still more  improperly ens ve-
neris, were once much esteemed; but are
now little  used, as they  are nauseous in
solution, and cannot very  conveniently be
given in any other form.
   Carbonic acid, dissolved in water,  com-
bines with a considerable quantity of iron,
in proportion to its mass.
   Phosphoric acid unites with  iron, but
very slowly.  The union is  best effected by
adding an alkaline phosphate to a solution
of one of the salts of iron,  when it will
fall down in  a white precipitate. This acid
is found  combined with iron  in  the bog
ores, and being at fii\-.t taken for a peculiar
metal, was called siderite by Bergmann.
   Liquid fluoric acid attacks iron with vio-
lence; the solution is not crystallizable, but
thickens to a jelly, which may be rendered
solid by continuing the heat.  The acid
may be expelled by  heating it strongly,
leaving a fine red oxide.
  Borate of iron  may be obtained by pre-
cipitating a solution of the sulphate with
neutral borate of soda.
  Arsenic acid likewise unites with iron.
This arseniate is found native.
  Chromate of iron has been found in the
department of Var in  France, and  else-
where.
  Sulphur combines very readily with iron.
A mixture of iron  filings and flowers of
sulphur being moistened, or made into a
paste, with  water, becomes  hot, swells,
adheres together,  breaks, and emits wa-
tery vapours of an hepatic smell.   If the
mixture be considerable in quantity, as for
example,  one hundred pounds, it takes fire
in twenty or thirty hours, as soon as the
aqueous vapours cease.
  By fusion with iron, sulphur produces a
compound of the same nature as the pyri-
tes, and exhibiting the same radiated struc-
ture  when broken.  If a bar of iron  be
heated to whiteness, and then touched with
a roll of sulphur, the two substances com-
bine, and  drop down together in  a fluid
state.  Mr. Hatchett found, that the mag-
netical pyrites contains the  same  propor-
tion as the artificial sulphuret.
   Phosphorus may be combined with iron
by adding it, cut into small  pieces, to fine
iron  wire heated moderately red in a cru-
cible; or  by  fusing six parts of iron clip-
pings, with six of glacial phosphoric acid,
and one of charcoal poweler.  This phos-
phuret is magnetic; and  Mr. Hatchett re-
marks, that iron, which in its 30ft or pure
 state cannot retain magnetism, is  enabled
to  do so,  when hardened by  carbon, sul-
phur, or  phosphorus, unless the  dose be
so  great  as  to destroy the  magnetic pro-
perty, as  in most of the natural pyrites and
plumbago.
   The combination of carbon with iron is
of  all the most important, and under the
names of Cast-Iron and Steel will be con-
 sidered in the  latter part of the present
 article.
   Iron unites with  gold, silver, and platina.
 When heated to a white heat, and plunged
 in mercury, it becomes covered with a coat-
 ing of that metal.  Mr. A. Aitken unites an
 amalgam of zinc and mercury with iron fil-
 ings, and then adds muriate of iron, when a
 a decomposition takes place, the muriatic
 acid combining with  the  zinc,   and the
 amalgam of iron and mercury assuming the
 metallic  lustre by  kneading, assisted with
 heat.  Iron and tin very readily  unite to-
 gether.  Iron does not  unite easily  with
 bismuth, at least in the direct way.  This
 alloy is brittle and attractible by the mag- 
IRO
IRO
liefc, even with three-fourths of bismuth.
As nickel cannot be  purified from  iron
without the greatest difficult}-, it  may be
presumed, that these substances readily
unite.  Arsenic forms a brittle substance in
its combination with iron.  Cobalt forms a
hard mixture w ith iron, which is not easily
broken.  Manganese is almost always united
with iron in the  native state.  Tungsten
forms a brittle, whitish-brown, hard alloy,
of a compact texture,  when fused  with
"white crude  iron.  The  habitudes of iron
with molybelena are not known.
   Iron is the most  diffused, and  the  most
abundant of metallic substances.   Few mi-
 neral boeiies or stones are without an ad-
 mixture  of this  metal.  Sands, clays, the
 waters of rivers and springs, are scarcely
 ever perfectly free from it.  The parts  of
 animal and  vegetable  substances likewise
 afford iron in the residues they leave after
 incineration.  It has been found  native, in
 large masses, in Siberia, and in the internal
 parts of South America.  This metal, how-
 ever, in its native state is scarce :  most iron
 is found in  the state of oxide, in ochres,
 hog ores, and other friable earthy substan-
 ces, of a red, brown, yellow, or black co-
 lour.  The magnet or loadstone, is an iron
 ore.  Iron is also found in combination with
 the sulphuric acid, either dissolved in wa-
 ter, or in the form of sulphate.
    In the large iron-works, it is usual to
  roast or calcine the ores of iron, previous
  to their fusion; as well for  the purpose
  of expelling sulphureous or arsenical parts,
  as to render them more easily broken into
  fragments of a convenient size for melting.
  The mineral is  melted or  run down, in
  large furnaces, from 16 to  30  feet high;
  and variously shaped, either conical or ellip-
  tical, according to the  opinion of the iron-
  master. Near the bottom of the furnace is
  an aperture for the insertion ofthe  pipe of
  large bellows, worked by water or steam, or
  of other machines for producing a  current
   of air;  and there are also holes at proper
   parts of the edifice, to be occasionally open-
   ed, to permit the scoriae and the metal to
   flow out, as the process may require. Char-
   coal  or coak, with lighted brushwood, is
   first thrown in ; and when the whole inside
   of the furnace has acquired a strong igni-
   tion, the ore is thrown in by small quantities
   at a time, with more of the fuel, and com-
   monly a portion of limestone, as a flux; the
   ore gradually subsides into the hottest part
   of tlie furnace, where it becomes fused; the
   earthy part being converted into a kind of
   glass ; while the metallic part is reduced by
   the coal,  and falls through the  vitreous
   matter to the lowest place.  The quantity
   of fuel, the additions, and the heat, must be
   regulated, in order to obtain iron of any de-
   sired quality; and this quality must likewise,
   in the first  product, be  necessarily dlti'e*
rent, according to the nature of the parts
which compose the ore.
  The iron which  is obtained  from  the
smelting furnaces is not pure ; and may be
distinguished into three states : white crude
iron,  which is brilliant in its fracture,  ami
exhibits a crystallized texture, more brittle
than the other kinds, not at all malleable,
and so hard as perfectly to withstand  the
file : gray crude iron, which exhibits a gra-
nulated and dull texture when broken ;  this
substance  is not so hard and brittle as the
former, and is used in the fabrication of ar-
tillery and other articles which require to
be bored,  turned or repaired:  anel black
 cast-iron, which is still rougher in its frac-
 ture ; its parts  adhere together less  per-
 fectly than those ofthe gray crude iron.
   In order to convert it into malleable iron,
 it is  placed  on a hearth,  in  the midst of
 charcoal, urged by the wind of two pair of
 bellows.  As soon as it becomes fused, a
 workman continually stirs it with along iron
 instrument.   During the course of several
 hours it becomes gradually less fusible, and
 assumes the consistence of paste.  In this
 state it  is carried to a large hammer, the
 repeated  blows of which  drive out all the
 parts that still partake of  the  nature  of
 crude iron so much as to retain the  fluid
 state. By repeated heating and hammering,
 more of th e fusible iron is forced out; and
 the  remainder, being malleable, is formed
 into a bar or other form  for sale.  Crude
  iron loses upwards of one-fourth of its
  weight in the  process of refining; some*
  times indeed one-half
    Purified or bar iron is soft, ductile, flex-
  ible, malleable, and possesses all the quali-
  ties which  have been enumerated  under
  this article as belonging exclusively to iron.
  When  a  bar of iron is  broken, its texture
  appears fibrous ; a property which depends
  upon the mechanical action of the hammer,
  while the metal is cold.  Ignition destroys
  this fibrous texture, and renders the iron
  more uniform throughout; but hammering
  restores it.
     If the purest malleable iron be bedded in
  pounded charcoal, in  a  covered  crucible,
  and kept for a certain number of hours in a
  strong red heat, (which  time  must be lon-
   ger or shorter, according to the greater or
   less thickness of the bars of iron),  it is
   found, that by this operation, which  is.call-
   ed cementation, the iron has gained a small
   addition of weight, amounting to about the
   hundred and fiftieth, or the two-hundredth
   part;  ami  is remarkably  changed in its pro-
   perties. It is much more brittle and  fusible
   than before.  Its  surface is commonly blis-
   tered, when it comes out of the crucible j
   and it reciuires to be forged, to bring its.
   parts together into a firm and continuous
   state.   This cemented iron is called steel.
   It mav  be welded like  bar iron, if  it haye.
                      16 
                IRO

not been fused, or over-cemented; but its
most useful anel advantageous property is
that of becoming extremely hard when ig-
nited and plunged into cold water.  The
hardness produced is greater in proportion
as the steel is hotter, and the water colder.
The colours which appear on the surface
of steel slowly heated are yellowish-white,
yellow, gold  colour, purple, violet,  deep
blue, yellowish-white;  after which the ig-
nition takes place.  These signs  direct the
artist in tempering or reducing the harelness
of steel to any determinate standard.   If
steel be too hard, it will not be proper for
tools which are  intended to have a fine
edge, because it will be so brittle, that the
edge will soon become  notched; if it be too
soft, it is evident, that the  edge will bend
or turn. Some artists ignite their tools, and
plunge them into cold water: after winch,
they brighten the surface ofthe steel upon
a stone: the tool being then laid upon char-
coal, or upon the surface of melted  lead,
or placed in the flame of a candle, gradual-
ly acquires the desired colour;  at which
instant they plunge it into water. If a hard
temper be desired, the  piece is  dipped
again, and stirred about in the cold water,
as soon as the yellow tinge appears. If the
purple appear before the dipping, the tem-
per will be fit for gravers, and tools used in
working upon metals; if dippeel while blue,
it will be proper for springs, and  for instru-
ments used in the cutting of soft substan-
ces, such as cork, leather, anel the like ; but
if the last pale colour be  waited for, the
hardness of the steel will scarcely exceed
that of iron.  When soft  steel is heated to
any one of these colours, and then plunged
into water, it  does not acquire nearly so
great a degree of hardness, as if previously
made quite hard, and then reeluced by tem-
pering.  The  degree of  ignition required
to harden steel is different  in the different
kinds.  The best kinds require only a low
red heat.   The harder the steel, the more
coarse and granulated its fracture will be;
and as this is not completely remedied by
the subsequent tempering, it is adviseableto
employ the least  heat capable of affording
the requisite hardness.
   The usual time required for the cemen-
tation of steel is from six to ten  hours.  If
the cementation be continued too long, the
steel becomes porous,  brittle, of a darker
fracture, more fusible, and incapable of be-
ing  forged or welded.  On  the contrary,
steel cemented with earthy infusible pow-
ders, is gradually reduced to the state of
forged iron again.  Simple ignition produ-
ces the same effect; but is atteneled with
oxielation d' the surface.  The texture of
steel is rendered more uniform by fusing
it before it is made into bars : this is called
cast steel; and is rather more  difficultly
wrought than common steel, because it is
                 IRO

more fusible,  and is dispersed under the
hammer if heated to a white-heat.
   The English steel maele by cementation,
and afterwards fused, and sold  under the
name of cast steel, in bars, plates, and other
forms, possesses great reputation for its uni-
formity of texture, and other good qualities.
I have been informed by various authorities,
of which the respectability and connexions
are calculated to produce the most absolute
confidence,  that  all the  prime steels of
England are  made from  Swedish  iron,
known in this country by the name of steel
iron, of three different marks, the first of
which  indicates  the best quality, and the
third the worst.
   The comersion of iron into steel, either
by fusion, viz. the direct change of crude
iron  into steel,  or  by  cementation of bar
iron, presents many  objects of  interesting
inquiry.  From \ arious experiments of Berg-
mann,itappeared,that good crude iron, kept
for a certain time in  a state of fusion, with
such additions as appeared calculated to
produce little other effect than that of de-
fending the  metal from oxidation,  became
converted into steel with loss of  weight.
These facts are conformable to the general
theory of Vandermonde,  Monge, and Ber-
thollet: for, according to their researches,
it  shoulel follow that part of the  carbon in
the cruele iron was dissipated, and the re-
mainder proved to be such in proportion as
constitutes steel.  The same chemist ce-
mented crude iron with  plumbago, or car-
bonate of iron, and found that the metal had
lost no weight.  Morveau repeated the ex-
periment with gray crude iron.  The loss
of weight was little,  if any.  The metal ex-
hibited the black spot by the application of
nitric acid, as steel usually docs, but it did
not harden by ignition and plunging in wa-
ter.  Hence I conclude, that it was scarcely
altered; for crude irons also exhibit  the
black spot, and camv »t by common manage-
ment acquire the hardness of steel.
   By pursuingthis train of reflection, it will
follow, that, since crude iron differs from
steel only in the superabundance of carbon,
it ought to be capable of extreme hardness,
if ignited to that degree, which is requisite
to combine the  greater part of this carbon
with the iron, and then suddenly cooled.
This is accordingly found to be the case. If
the gray crude iron, commonly distinguish-
ed by our founders by the name of soft me-
ted,  be heated to a white heat, and  then
plungeel into water, it becomes very hard,
much  whiter, denser, and more metallic in
its appearance ; and will bear a pretty good
edge fit  for gravers, for the use of turners
in iron or steel.  In these tools the angle of
the planes which form the edge  is about
45°.   The hardness of this kind of iron is
not considerably diminished but by ignition
continued for a length of time, which is- a 
IRO                                   IRO
fact also conformable to what happens in
steel.  For the cast steel will be softened
nearly as much by annealing to the straw
colour, as the harder steels are by anneal-
ing to a purple^or full blue.
  Some of our artists have taken advantage
of this property of soft crude iron in the fa-
brication of axles and  collars for wheel-
work ; for this material is easily  filed and
turned in  its soft s ate, and ma afterward
be hardened so as to endure a much longer
time of wear.
  The founders who cast wheels and other
articles of mechanism, are occasionally em-
barrassed by this property.   For, as the
metal is poured into their moulds of moist-
ened sand, the evaporation of the water
carries off' a great portion of the heat, and
cools the iron so  speedily, as to reneler it
extremely hard, white, and close in its tex-
ture. This is most remarkable in such por-
tions of the metal, as have the greatest dis-
tance to run from  the  git or aperture  of
reception. For these come in contact suc-
cessively with a larger portion ofthe  sand,
and are therefore more suddenly cooled.  I
have seen the teeth of cog-wheels altoge-
ther in this state, while the rim and  other
parts ofthe wheel remained soft. The ob-
vious remedy for this defect is to increase
the number of gits, and to have the sand as
dry as possible or convenient. In other ar-
ticles this property has been applied  to ad-
vantage, particularly in the steel rollers for
large laminating mills.
   i have been informed by a workman, that
ignited iron, suddenly plunged into the soft
leather of a shoe, becomes very hard on its
surface, which must arise from an instanta-
neous effect of case hardening.
   The increase of dimensions acquired by
steel in hardening is such, that, in general,
pieces of work finished soft will not fit their
places when hardeneel.
   The fineness of grain in hard steel, as ex-
hibited in its fracture, is various according
to the quality ofthe metal, and the temper
jt has received.  The harder the steel the
coarser the grain   But in like circumstan-
ces, fine steel has the closest grain, and is
ever the most uniform in its appearance.
Workmen avail  themselves much of this
indication.  In general a neat curve lined
fracture,  and even gray texture, denote
good steel; and the appearance of threads,
cracks, or brilliant specks, denotes the con-
trary.   But the management of the forging
and other circumstances of manufacturing
will modify these indications;  and the steel
that is good for some purposes, may be less
suited to others.
   It is found, that steel is more  effectually
hardened in cold than in warm  water, and
at like  temperatures more effectually  in
mercury  than  in water.  Oil is found  to
harden the surface of steel much more than
its internal part, so that it resists the file,
but is much less easily broken by the ham-
mer.  Tallow differs from oil in the heat
which becomes latent for its fusion; and
accordingly, solid tallow is an excellent ma-
terial for hardening drills and other small
articles.  The makers  of files cover them
with the grounds of beer and common salt,
which assist their hardening,  and keep the
surface from scoruying. The mucilage of
the  beer supplies a coaly matter; and the
fused salt forms a varnish in the fire and de-
fends the steel.  Very small articles heated
in a candle are found to be hardened per-
fectly by suddenly whirling them in the cold
air; and thin bars or plates of steel, such as
the magnetic needle of a compass, acquire
a good degree of hardness by being ignited,
then laid on a plate of cold lead, and sud-
denly covered with another plate.  These
would be unequally hardeneel, and bend, if
plunged in water.
   The black spot which remains upon steel,
or crude iron, after it  surface has been cor-
roded by acids, consists of plumbago, which
remains after the iron  has disappeared by
solution.
   Solution in the sulphuric or muriatic acid
not oidy exhibits the plumbago contained
in iron, but likewise possesses the advan-
tage of showing the state of its reduction by
the quantity of hydrogen gas which is dis-
engaged ; for the quantity of this gas, in like
circumstances, is proportional to that ofthe
iron which is converted into oxide.   It is
found, that the white crude iron affords the
least quantity of hydrogen in proportion to
its bulk, and leaves a  moderate portion of
plumbago; the gray crude iron affords more
hydrogen, and  more plumbago than the
white ; and the softest bar iron affords most
 hydrogen of any, and little or no plumbago.
 The quantities of hydrogen gas, at a medi-
 um, by ounce measures, were 62,  afforded
 by 100 grains of the white crude iron; 71
 by the gray crude iron; and 77 by the malle-
 able iron.
   Iron is one of the  principal ingredients
 for dyeing black. The stuff'is first prepared
 with a bath of galls and logwood, then with
 a similar bath to  which verdigris is added,
 and lastly dyed in a  similar buti>,  with the
 addition of sulphate of iron.   If it be wish-
 ed, that the colour should be  particularly
 fine, the stuff'should previously be dyed of
 a deep blue ; otherwise a brown may  be
 first given with the green husks of walnuts.
 Silk however must not be previously blued
 with indigo, and sumach may be substituted
 instead of galls.  Leather prepared by tan-
 ning with oak bark, is blackened by a solu-
 tion of sulphate of iron.
   Cotton has a very strong affinity for oxide
 of iron, so that, if it be immersed in a solu-
 tion of any salt of iron, it assumes a chamois
 colour, more  or less deep according to the 
IRO                                   IRO
strength ofthe solution.  The action of the
air on the oxide of iron deepens the colour;
and it the shade were at first deep, the tex-
ture ofthe stuff is liable to be corroded by
it.  To prevent this, the cotton should be
immersed in the solution cold,  carefully
wrung, and immediately plunged into a ley
of potash mixed with  a solution of alum.
After having lain in this four or five hours,
it is to be wrung, washed, anel dried.
   In order to prevent gun-barrels from rust-
ing they are frequently browned.   This is
done by rubbing it over when finished with
aquafortis or spirit of salt diluted with wa-
ter, and hiving it by for a week or two till a
complete coat  of rust is formed.   A little
oil is then applied, and the surface, being
rubbed dry, is polished by  means of a hard
brush and a little bees' wax.
   The  yellow  spots called  iron  moulds,
which are frequently occasioned  by wash-
ing ink spots with soap, may in general be
removed  by lemon-juice, or the oxalic or
citric acids; or by  muriatic acid diluted
with five or six parts of water, but this must
be washed off' in a minute or two.  Ink
spots may readily be removed by the same
means.   If the iron mould have remained
so long, that the iron is very highly oxidi-
zed, so as to be insoluble in the acid, a so-
lution  of an alkaline sulphuret may be ap-
plied, and, after this  has been well washed
off the acid will remove the stain.
   * To the preceding details, which are se-
lected  from  Mr. Nicholson's work, I shall
subjoin a short systematic view ofthe  che-
mical nature and relations of iron.
   I. Of pure iron.
   Its specific gravity is  7.7, but it may be
made 7.8 by hammering.  Under the arti-
cle Cohksion,  the tenacity of iron is given
in reference to other solids. In malleability
it is much inferior to gold, silver, and cop-
per ; though in ductility it approaches these
metals ; for iron wires of l-150th of an inch,
are frequently drawn.   Is melting point is
estimated  by  Sir G. Mackenzie  at  158°
Wedge wood; the extreme heat of our che-
mical furnaces.
   Dr.   Wollaston first showed,  that the
forms in which native iron is  disposeel to
break,  are those ofthe regular octahedron
and tetrahedron, or rhomboid, consisting
of these forms combined.  In a specimen
possessed  by this philosopher, the crystal-
line surfaces appear to have been the re-
sult of a process of oxidation which has
penetrated the mass to a considerable depth
in the direction of its  laminae;  but in the
specimen which is in the possession of the
Geological  Society, the brilliant  surfaces
that have been  occasioned by forcible se-
paration from the original mass, exhibit also
the same configurations as are  usual in the
fracture of octohedral  crystals,  and  are
•found in many simple  metals.  This spon-
taneous decomposition of thf metal in the
direction of its crystalline laminx is a new
and valuable fact.
  From  Mr. Danicll's ingenious  expert-
ments on the mechanical structure of iron,
developed by solution, we learn, that a
mass of bar iron which had undergone all
the operations of puddling anel rolling, af'.cr
being left in liquid muriatic acid, till satu-
ration, presented the appearance of a bun-
dle of fasces,  whose  libres run  parallel
through its whole length.   At its two ends,
the points were perfectly eletached from
each other, and the rods  were  altogether
so distinct, as  to appear  to the  eye  to be
but loosely compacted.
  II.  Compounds of iron.
  i. Oxide; of which there  are  two, or
perhaps three.
  1. The oxide, obtained either by digest-
ing an excess of iron filings in water, by the
combustion of iron wire  in oxygen, or by
adding pure ammonia to solution of green
copperas, and drying the precipitate out of
contact of air, is of a black colour, becoming
white by its union with water, in the hy-
drate, attractible by the  magnet, but more
feebly than  iron. By  a mean ofthe experi-
ments of  several chemists, its composition
seems to be,
      Iron,    100     77.82    3.5
      Oxygen, 28.5    22.18    1.0
Whence the prime equivalent of iron comes
out, we perceive, 3.5.  SirH. Davy's num-
ber, reduced to the oxygen scale,  is 6.86,
one-half of which, 3.43, is very nearly the
determination of Berzelius.  But Mr. Por-
rett, in an ingenious paper published in the
Annals  of Philosophy for October  1819,
conceives that to make the theoretical pro-
portions relative to iron harmonize with
the experimental results, we must consider
1.75,  or the half of 3.5,  as  its  true prime
equivalent, or lowest term of combination.
The protoxide will then consist of 2 primes
of iron  to 1 of oxygen.
  M. Thenard, in his Traite', vol ii.  p. 73.
says,  the above  oxide, obtained by decom-
posing protosulphate of iron by potash or
soda, and washing the precipitate in close
vessels with water deprived of its air, con-
sists,  according to  M. Gay-Lussac, of  100
parts of iron, and 25  of oxygen.  This de-
termination would make the atom of iron
4.0 ;  and is probably incorrect.  This pro-
portion is proved, he adds, by dissolving  a
certain quantity of iron in dilute sulphuric
acid, anel collecting the evolved hydrogen.
Now, by  this method extreme precision
should be ensured.
  2.  Deutoxide of M.  Gay-Lussac.  He
forms it, by exposing a coil of fine iron wire,
placed  in an ignited  porcelain tube, to a
current of steam, as long as any hydrogen
comes over.  There is no danger, he says,
of generating peroxide in this experiment; 
IRO
mo
because iron, once in the state of deutoxide,
has no such affinity for oxygen, as to enable
it to decompose water.  It  may also, he
states, be procured by calcining strongly a
mixture of 1 part of iron and 3 parts ofthe
red oxide in a stone-ware  crucible, to the
neck of which a tube is adapted to cut off
the contact of air.  But this process is less
certain  than the first; because a portion  of
peroxide may  escape the  reaction of the
iron.   But we may dispense with the trou-
ble of making it, adds M. Thenard, because
it is found  abundantly  in nature.   He re-
fers to this oxide, the crystallized specular
iron  ore of Elba, Corsica, Dalecarlia, and
Sweden.   He also classes under this oxide,
all  the  magnetic iron ores; and says, that
the above  described protoxide does not
•xist in nature.   From the synthesis of this
•xide by steam, M. Gav-Lussac  has deter-
mined i1 s composition to be,
       Iron,     100    72.72
       Oxygen,  37.5  27.28, which  Mr.
Porrett reconciles to theory, by represent
ing it as consisting of
  3 primes iron,   5.25    72.5    100
  2       oxygen, 2.00    27.5      38
  3. The red oxide.  It  may be obtained
by  igniting the nitrate, or carbonate; by
calcining iron  in open vessels; or  simply
by  treating the  metal  with  strong nitric
acid,  then  washing  and drying the  resi-
duum.  Colcothar of vitriol, or thorough
calcined copperas,  may be considered  as
peroxide of iron. It exists abundantly na-
tive in the red iron ores.  It seems to be a
Compound of,        By Mr.  Porrett.
      Iron,     100  70 = 4 primes.
      Oxygen,    43  30 = 3 primes.
  2. Chlorides of iron; of which there are
two, first examined in detail by Dr. Davy.
  The  protochloride may by procured by
heating to redness, in a glass tub6  with a
very small  orifice, the residue, which is ob-
tained by evaporating to dryness the green
muriate of iron.  It is a fixed substance, re-
quiring a  red heat for its fusion. It has a
grayish variegated colour, a metallic splen-
dour, and  a lamellar texture.  It absorbs
chlorine when heated in this gas, and be-
comes entirely converted into the volatile
deutochloride.   It consists, by Dr. Davy, of
             Iron,     46.57
            Chlorine, 53.43
By  Mr.  Porrett,
    2 primes iron,    3.5  43.75 100.0
    1       chlorine, 4.5  56.25 128.7
  The deutochloride may be formed by the
combustion of iron wire in chlorine  gas,  or
by  gently heating the green  muriate in a
glass  tube. It  is the volatile compound,
described by Sir H. Davy in his celebrated
Bakerian lecture on oxymuriatic acid.  It
condenses after sublimation, in the form of
small brilliant iridescent plates.
It consists, by Dr. Davy, of iron,    35.1
                         chlorine, 64.9
By Mr. Porrett,
  4 primes iron,     7.0  34.14  100.08
  3       chlorine, 13.5  65.86  192.85
  3. For the iodide of iron, See Iodine.
  4. Sulphurets of iron; of which, accord-
ing to Mr. Porrett, there are four, though
only two are usually described, his protosul-
phuret, and persulphuret.
  The protosulphuret of iron exists in na-
ture.  It has the  metallic  appearance of
bronze, but  its powder is blackish-gray. It
is in fact the magnetic pyrites of mineralogy,
which see among the Ores of iron.  By the
analyses of Mr. Hatchett  and  Professor
Proust, it seems to consist of iron,    63
                           sulphur, 37
Mr. Porrett  represents it as composed of
  2 primes iron      =  3.5  63.75  100
  1       sulphur      2.0  36.25   57
  His deutosulphate and tritosulphate are
as follows:
Deutos. 3 primes iron,      5.25  57  100
        2       sulphur,   4.00  43   76
Tritos.  4 primes iron,      7.0   54  100
        3       sulphur,   6.0   46   86
  He conceives, that in Proust's experi-
ments, as related in the 1st volume of Nichol-
son's 8vo Journal, descriptions of com-
pounds corresponding to those two sulphu-
rets are given.
  The protosulphuret is the cubic iron py-
rites ofthe mineralogist. It consists, by Mr.
Porrett, of
  1 prime iron,    1.75  46.5  100.0
  1      sulphur, 2.00  53.5  114.2;  and
the mean of Mr. Hatchett's celebrated expe-
riments on pyrites, published in the Phu\
Trans, for 1804, gives of iron,     100
                       sulphur, 113
  5. Carburets of iron.   These compounds
form steel, and probably cast iron ; though
the latter contains also  some other  ingre-
dients.  The latest practical researches on
the constitution of these carburets, are those
of Mr. Daniel!, above quoted.
  A mass of steel just taken from the cruci-
ble in which it had been fused, was subject-
ed to the action of muriatic acid.  It was of
a radiated texture. When withdrawn from
the solvent, it presented a high crystalline
arrangement, composed of minute brilliant
plates.  A bar of steel of an even granular
fracture being broken into two, the  pieces
were heated in a furnace to a cherry-red.
In this state one of them was plunged into
cold water,  and the other allowed to cool
gradually by the slow extinction ofthe fire.
They were  then  both  placed in muriatic
acid, to which a few drops of nitric acid had
been added. The softened piece of steel
was readily  attacked; but it required a pe-
riod five times greater to saturate the acid
with the hard piece. When the solvent had
ceased to act on both, they were examined.
The hard steel was exceedingly brittle, its
surface was  covered with small cavities like
worm-eaten wood, but its text«re was very 
IRO                                  IRO
compact, and not at all striated. The other
piece was inelastic and flexible, and pre-
sented a fibrous and wavy texture. On this
texture, the excellence of iron for mechan-
ical purposes i- known to depend; and the
parts not fibrous are thrown off by the- pro-
cesses of pudelling and hammering. By cut-
ting the iron bars into short pieces repeated-
ly, tying them in bundles, and welding them
together,  a similar interlacement of fibres
is given to this valuable metal, as to flax and
hemp,  by carding and spinning.  May not
the superior quality ofthe Damascus sword
blades,  which  is still a problem, says Mr.
Daniell, to our manufacturers, be owing to
some such management? A specimen of
white cast iron, of a radiateel fracture, took
just three times as long to saturate a given
portion of acid, as a cube of gray cast iron,
or a mass of bar iron.  Its texture, after this
action, appeared to be composed of a con-
geries of plates, aggregated in various po-
sitions,  sometimes  producing stars  upon
the surface, from the intersection of  their
edges.  A  small bar of cold short iron, ex-
ceedingly brittle, and presenting in its frac-
ture bright and polished surfaces, resem-
bling antimony, after the action of the acid
proved to be fibrous.  A rod of hot short iron
presented,  at  the  end of the operation, a
closely compacteel mass of very small fibres,
perfectly continuous. The congeries was
twisted, but  the threads preserved  their
parallelism.
  MM. Berzelius and Stromeyer produced
a compound, which they consider as a com-
bination  of iron, carbon, and silicium, the
unknown basis of silica. They mixed into a
paste with gum or linseed oil,  very  pure
iron, silex, and charcoal, and heated the
mixture very intensely in a covered cruci-
ble. They inferreel that silicium, in the me-
tallic or inflammable  state, existed in the
product, because the sum ofthe iron and
silex extracted from the alloy, very sensi-
bly exceeded the total weight ofthe alloy;
because  the alloy  gave a much greater
quantity of hydrogen, with muriatic acid,
than the  iron  alone which  it  containeel
would have afforded; and because there is
no known  combination of a metal with an
earth, which requires the successive opera-
tion ofthe most powerful agents to decom-
pose it, as this alloy did. The colour of this
compound was that of common steel.
  The quantities of the component  parts,
however, of this alloy, differed very  mate-
rially, from those of the purified carburet
obtained from cast iron. The former varied
from the proportions of
          Iron,      85.3 to 96.1
          Silicium,    9.2    2.2
          Carbon,     5.3      1.6
  The artificial compound was highly mag-
netical, while the triple carburet is not.
Mr. Daniell,  in examining  by solution in
acid, a cube of gray cast iron, obtained a
porous spongy substance,  untouched  by
the menstruum.  It was easily cut off by a
knife; had a  dark gray colour, some what
resembling plumbago, and when placed in
considerable quantity  on  blotting paper to
dry, it spontaneously  heated, ignited and
scorched  the  paper.   Its properties were
not impaired by being left for weeks in the
solution of iron, or in water.  After a series
of el-iborate  analytical experiments,  Mr.
Daniell infers  the composition of this cast-
iron to be,
Iron,          84.66
r.  •          ,£n,( silex,        10.13
Foreignmatter, 15.o4 J double carbur. 4M

                                  15.34
And 100 grains of the double carburet of
iron and silex upon an average of 5 experi-
ments, gave the following results:
Red oxide ; 31 2 = 28 Q  Wack oxide
  ot iron,  >
Silex,       22.3 =. 20.6 oxide of silicium ?
Carbon,     51.4=51.4
           104.9  100.0~
  Although the existence of silicium in the
metallic  state alloyed with iron, is not ac-
tually demonstrated by the preceding ex-
periments, yet it is  renelered extremely
probable.  But, as Mr.  Daniell remarks,
much  remains to be done to complete our
knowledge of the nature  of cast iron.
  The composition of steel is also very va-
riable.  According to M.. Vauquelin, the
carbon forms T^ part, on an average.   By
enclosing diamonels in cavities of soft iron,
and igniting; the former disappeared, and
the inner surface ofthe latter was convert-
ed into steel.   Mr. Clouet makes the car-
bon in cast iron = $ of the whole weight.
But Berzelius makes  the latter species a
very complex compound.  A  specimen of
very pure cast iron analyzed by him, yielded,
           Iron,        90.83
           Silicium,     0.50
           Magnesium,  0.20
           Manganese,  4.57
           Carbon,      3.90
                      100.00
  Mr. Mushet has inserted  in several vo-
lumes of the Phil. Magazine, many excellent
papers on the manufacture and habitudes
of iron.   In the 5th volume of the Manches-
ter Memoirs, a good account ofthe process
used at Sheffield for  converting cast iron
into pure iron, and pure iron into steel, has
been  published by Mr. Joseph Collier.  He
has given a drawing of the steel furnace of
cementation.  I regret that  the limits of
this work prevent me from  transcribing
their valuable communications.   I shall
merely annex Mr. Muschet's  table of  the
proportions of carbon  corresponding to dif-
ferent carburets of iron.
  T^ff Soft cast steel.
  T^5 Common cast steeT. 
IRO                                   IRO
  -*—  The same, but harder.
  so
   *   The same too hard for drawing.

  5j  White cast iron.
   1
  ■£5"  Mottled cast iron.
  TT Black cast iron.
  Graphite or plumbago, is also a carburet
of iron ;  containing about 10 per cent of
metal, which  calling the prime of iron 1.75,
makes it a compound of 21 primes of car-
bon to I of metal.   This congregation of
carbonaceous atoms, by a singular enough
•oincielence, is  precisely that assigned by
Dr. Thomson, in his analysis of coal, as the
number clustered round azote, a body whose
atomic weight  is also 1.75.  See Annals of
Phil, for August 1819, p. 93. This analogy
may perhaps be regarded, by  those  who
hum after harmonic numbers, as at once a
demonstration  of the  atom of iron being
1.75; and  of an atom of carbon requiring
for saturation  21   atoms  of a  substance,
whose prime equivalent is to its own, as
1.75 is to 0.75.   It is,  however, rather un-
lucky for this fancy, that cy anogen or prus-
sine has been discovered.
  Pure iron  becomes  instantly magnetic,
when presented to a magnetic bar;  and as
speedily loses its magnetism, when the bar
is withdrawn. Its coercive power, in resist-
ing the decomposition or recomposition of
the austral and boreal  magnetisms, is ex-
tremely feeble. But when iron is combined
with oxygen, carbon, sulphur or phospho-
rus, it acquires the magneto-coercive virtue,
which attains a maximum of force, with cer-
tain proportions of the constituents, hither-
to undetermined.  Mr  Hatchett is the only
chemist who has adverted to this subject, in
a philosophical manner.—" Speaking gene-
rally ofthe carburets, sulphurets, and phos-
phurets of iron, I have no doubt," says he,
"but  that, by accurate experiments, we
shall find, that a certain proportion of the
ingredients of  each, constitutes a maximum
in the magnetical power of these three bo-
dies."
   The most useful alloy of iron, is that with
tin, in tin-plate. The" surface  of the iron
plates is cleaned first, by steeping in a crude
bran-vinegar, and then in dilute sulphuric
acid ; after which they are scoured  bright
with hemp and sand, and deposited in pure
water, to  prevent oxidation.   Into  a pot,
containing equal parts of grain and block-
tin in a state of fusion, covered with tallow,
the iron plates are immersed in a vertical
direction, having been previously kept for
about an hour  in melted tallow. From 300
to 400 plates are tinned at a time: each par-
 cel requires an hour and a half for mutual
incorporation  of the metals.  After lifting
out the tinned plates, the striae are removed
 from  their surfaces, and  under edges, by
 subsequent  immersion in  mdted tin, and
then in melted tallow, wiping the surface*
at the same time with a hempen brush.
  Very curious and instructive experiments
on the alloys of steel with several metals,
with a view to improve cutting instruments
and  reflecting  mirrors,  have been  lately
made in the laboratory of the ltoyal Insti-
tution, of which an account is inserted in
the 18th number ofthe Journal of Science.
  Alloys of sled with platinum, rhodium,
golel, and nickel may be obtained, when the
heat  is sufficiently high.  This is so re-
markable with platinum, that it will fuse
when in contact with steel, at a heat at
which the steel itself is not affected.
  There are some very curious circumstan-
ces, attending the alloy of silver. If steel
and silver be kept in fusion together for a
length of time, an alloy is obtained, which
appears to be very perfect, while the me-
tals are in the fluid state ;  but on solidify ing
and cooling, globules of pure silver are ex-
pressed  from the mass, and  appear on the
surface of the button.  If an alloy of this
kind be forged into a bar, and then dissect-
ed by the action of dilute sulphuric acid,
the silver appears not in combination with
the  steel,  but in threads throughout the
mass; so that the whole has the appearance
of a bundle of fibres of silver and steel, as
if they  had been united by welding.  The
appearance of these silver fibres is very
beautiful; they  are sometimes  one-eighth
of an inch in length, and suggest the idea
of  giving mechanical toughness to  steel,
where a very perfect edge may not be re-
quired.  The most interesting result is the
following:—\V hen 1 of silver and 500 steel
 were properly fused together, a very per-
 fect  button  was produced;  no silver  ap-
 peared on its surface ; when forged and dis-
 sected by an acid, no fibres were seen, al-
 though  examined  by a high  magnifying
 power.  The specimen forged remarkably
 well, although very hard; it had, in every
 respect, the most favourable appearance.
 By a delicate test, every part of the bar gave
 silver.   This alloy is decidedly superior to
 the very best  steel, and this excellence  is
 unquestionably owing to combination with
 a minute portion of silver.   It has been re-
 peatedly made,  and always  with success.
 Various cutting tools have been made from
 it  ofthe best quality.  Mr. Stodart, a veiy
 eminent cutler, assisted at  these experi-
 ments, which  must give the public confi-
 dence in their practical results.
    Equal parts by weight, of platinum and
 steel, form a beautiful alloy, which  takes a
 fine polish, anel does not tarnish; the colour
 is the finest imaginable  for a mirror.  The
 sp. gr. of this beautiful compound is 9.862.
 The proportions of platinum that appear  to
 improve steel for eelge instruments, are from
  1 to 3 per cent.  While an alloy of 10 pla-
 tinum with  80  steel,  after  lying many 
IKO                                   IRO
months exposed, had not a speck on its sur-
face;  an  alloy of 10 nickel with 80 plati-
num, was in the same circumstances cover-
ed with rust.
  The alloys of steel with rhodium, would
prove highly valuable, were it not for the
scarcity ofthe latter metal.
  There  is a species of steel made in India,
called ivootz, possessed of excellent quali-
ties, which seems to have been successfully
imitated in these  late experiments at the
Royal  Institution.   In a  previous number
ofthe same Journal, (14th), Mr. Faraday
had detailed a minute, and apparently, a
very accurate analysis, operated  on a part
of one ofthe cakes of wootz, presented by
the Right Hon. Sir Joseph Banks, to Mr.
Stodart.   460 grains gave 0.3 of a grain of
silex, 0.6 of a grain of alumina.  42u grains
of the best English steel, furnished by Mr.
Stodart, afforded no earths w hatever. The
imitative synthesis was performed in the fol-
lowing way:—
  Pure steel in small pieces,  and,  in some
instances, good iron being mixed with char-
coal powder, were intensely heated for a
long time.  Thus, carburets, having a dark
green metallic colour, were formed, highly
crystallized, resemblingsomewhatthe black
ore of tellurium.   When broken, the facets
of  small  buttons, not weighing more  than
500 grains,  were  frequently  above  the
eighth of an inch in width.  The results of
several  experiments on  its composition,
which appeared very uniform,  gave 94.36
 iron -f- 5.64 carbon.  This being broken
 and rubbed to powder in a mortar, was mix-
 ed with  pure  alumina, and  the  whole in-
 tensely heated in a close crucible for a con-
 siderable  time.  On being removed from
 the furnace and  opened, an alloy was ob-
 tained of a white colour, a close  granular
 texture, and very brittle.  This, when ana-
 lyzed, gave 6.4 per cent,  of alumina, and
 a  portion of carbon not  accurately estimat-
 ed.  700 of good steel, with 40 of the alu-
 mina alloy, were fused together, and formed
 a  very  good button  perfectly malleable.
 This, on being forged into a little bar, and
 the surface polished, gave, on  the applica-
 tion of sulphuric acid, the beautiful damask,
 peculiar to wootz.  A  second  experiment
 was made with 500 grains of the same steel,
 and 67  of the  alumina alloy,  which also
 proved  good.   It forged well, and gave the
 damask.  This specimen had all the appre-
 ciable characters ofthe best Bombay wootz.
 It is highly probable, that  the much admir-
 ed sabres of Damascus,  are made from  this
 steel; and if this beadmitteel, there can be
 little reason to eloubt, that the damask itself
 is merely  an  exhibition of crystallization.
 Wootz  requires for tempering, to be heated
 fully 40° F. above the best  English  cast
 steel; and affords a finer and more durable
  edge.
    When soft steel is ignited to  a cherry-
  red, and suddenly plunged in cold water,
it is rendered so hard as to resist the file".)
and nearly as brittle as glass. The temper-
ing of steel consists in reducing this e- xces-
sive harelness to  a moderate degree, hy a
gentle  heating,  which  also  restores  its
toughness and elasticity.  In the year 1/89,
Mr. Hartley obtained a patent for a mode
of tempering cutting instruments ot seel,
by immersion in  oil, heated to a  ie-gulated
temperature, measured by a thermometer.
This was certainly a great improvement,
both in point of precision and despatch, on
the common method of neatmg the instru-
ment over a tiame, till a certain colour, pro-
duced by a fiim of oxide, appears on its sur-
face.  These colours are,
At 43j°  F. a very faint yellow, for lancets*
450
470
490

510

530

550
560
600
          a pale straw-colour for  razons
             and surgeons' instruments.
          a full yellow, for penknives.
          a brown colour, for scissarsand
             chisels for cutting cold iron.
          a brown, with  purple spots, for
             axes and plane-irons.
          a purple, for  table-knives and
             large shears.
          a bright blue, for swords, watch-
             springs,  truss-springs,  and
             bell-springs.
          a full blue, for small fine saws,
             daggers, &c.
          dark blue, verging on black, 19
             the softest of all the  grada-
             tions; when the metal be-
             comes fit only  for hand and
             pit-saws, which must be soft,
             that their  teeth  may  bear
             sharpening by the file, and
             setting  by  the hammer, or
             pliers.
  If the steel be heated still  further, it be-
comes perfectly soft.  When tools having a
thick back and  thin  edge, like penknives,
are to  be tempered, they are placed with
their back on a plate of hot iron or on hot
sand; otherwise they  would become too
soft at the edge, before- the backs would be
sufficiently heated.  To  prevent  warping
of long blades, or bars for  magnets, they
are generally hardened by being  plunged
vertically into  water.  It is evident, that
melted pewter, covered  with grease, may
be used instead of  hot oil  for tempering
steel;  the heat being regulated by a ther-
mometer.
   Salts of iron.
   These  salts  have the  following  gencrA
characters:—
   1. Most of them are  soluble in water;
those with the protoxide  for a base, are ge-
nerally cmAallizablc; those with the per-
oxide, are generally  not; the  former are
 insoluble, the latter soluble  in alcohol.
   2. lerroprossiate of potash throws down
 a blue precipitate, or one becoming blue in
 the air.
   3. Infusion of galls gives a dark purple
 precipitate,  or one  becoming so in the air 
IRO
IRO
  4. Hvdrosulphuret of potash or ammonia
gives a" black precipitate; but sulphuretted
hydrogen merely deprives the solutions of
iron of their yellow-brown colour.
  5. Phosphate  of soda  gives  a whitish
precipitate.
  6. Benzoate of ammonia, yellow.
  7. Succinate of ammonia, flesh-coloured
with the peroxide.
  1. Protucetate of iron forms small  pris-
matic crystals, of a green colour, a sweet-
ish  styptic taste, and a sp. gr. 1.368.
  2. Peracetate of iron forms  a reddish-
brown uncrystallizable solution, much used
by  the calico printers,  and prepared by
keeping iron-turnings, or  pieces  of old
iron, for six months immersed in redistil-
led pyrolignous acid.  See Acid (Acetic)
  3. Protarseniate of iron exists native in
crystals, and may be formed in a pulveru-
lent state, by pouring arseniate  of ammo-
nia into sulphate  of iron.   It is insoluble,
and consists, according to Chenevix, of 38
acid, 43 oxide, and 19 water, in  100 parts.
  4. Perarseniale  of iron may  be formed
by pouring arseniate of ammonia into  per-
acetate of iron; or by boiling nitric  acid
on the protarseniate.   It is insoluble.
  5. Antimoniate of iron is  white,  becom-
ing yellow, insoluble.
  6. Borate, pale yellow, insoluble.
   7. Benzoate, yellow,     do.
  8. Protocarbonate, greenish, soluble.
  9. Percarbonate, brown, insoluble.
  10. Chromate, blackish,    do.
  11. Protocitrate, brown crystals, soluble.
  12. Protoferroprussiate, white, insoluble.
  13. Perferroprussiate, blue,      do.
   This  constitutes the  beautiful pigment
 called  prussian blue.  When exposed to  a
 heat of about 400°, it takes fire in the  open
 air; but in close vessels it is decomposed,
 apparently into carburetted hydrogen, wa-
 ter, and  hydrocyanate of ammonia, which
 come  over; while a  mixture  of charcoal
 and oxide of iron remains  in the state of
 a pulverulent pyrophorus, ready to become
 inflamed with contact of air.  1  have alrea-
 dy considered the constitution of prussian
 blue, in  treating ofthe  Acid (Ferro-
 prussic); and have little farther  to add
 to what is there stated concerning this in-
 tricate compound.   I perceive that  Dr
 Thomson has recently published (Ann. ot
 Phil, for September 1820) a new igneous
 analysis of prussian  blue.  He  gives now
 satisfactory evidence,  that hydrocyanate of
 ammonia is one ofthe products, which his
 former short notice left somewhat >n doubt.
 But the details of his analysis are blended
 with so many theoretical suppositions, that
 instead of clearing up  the matter,  they
 seem to involve it in greater mystery.
  I shall avail myself, however, ot this op-
 portunity  of presenting my readers  with

   Vol.  IT.
the valuable investigations of M. Robiquet
on the nature of prussian blue, published
in the 12th vol. of the Ann. de Chimie et
Physique.
   When'sulphuric acid is added to prus-
sian blue, it makes it perfectly white,  ap-
parently by abstracting its water; for  the
blue colour returns on dilution of the acid,
anel if the  strong acid be  poured off, it
yields no traces of either prussic acid or
iron.   On submitting pure  prussian blue
for some time to the action of sulphuretted
hydrogen water, small brilliant crystals of
a'yellowish colour appeared, which became
blue in the air, and were protoprussiate of
iron:   M. Robiquet  has succeeded in  ob-
taining the acid of prussian blue in a solid
crystalline state, by a different process from
Mr. Porrett's.   Strong muriatic  acid, in
large quantity, being  mixed  with  pure
prussian blue, and left for some time,  the
sediment becomes of a green colour, and
then  yellow.  If water be  added to this
mixture, it  is  again  rendered blue; but if
no water  be added, and if it be allowed to
stand in a narrow vessel, the sediment falls
to the bottom, and a deep red-brown solu-
tion covers it.   This is an acid solution of
muriate  of  iron, and cannot be  made to
produce a blue by any method tried. The
sediment was allowed to contract itself for
several days,  and the supernatant liquor
"being drawn  off by a  little  syphon,  the
washing was then repeated with concen-
trated muriatic acid  as before, until  the
process was supposed to be complete. The
magma was now collected into a capsule,
and placed  in  a receiver, containing much
lime, to dry.  When  dry it was  digested
in alcohol, filtered and evaporated sponta-
neously, and a  number of  small crystals
were obtained.   These  crystals  were  se-
parated, washed in fresh alcohol, and again
crystallized; and were then the pure acid
of" prussian blue, or the ferrochyazic acid
of Mr. Porrett.
   These crystals appear at times to be te-
trahedral; they are white when pure;  but
become slightly blue by exposure to the  air.
They have no odour; their taste is acid and
peculiar, without being like that of prus-
sic acid.  They are  soluble in water  and
alcohol.  The colourless solution produces
an  immense precipitate of  prussian blue,
in persulphate of iron.  The acid perfectly
saturates potash,  and produces the com-
mon  triple  prussiate of potash.   If it be
heated, a considerable quantity of prussic
acid first passes off', the remainder becomes
of  a deep blue colour,  and  insoluble.—
When heated  in close vessels, the prussic
acid is given off as before, perfectly pure,
and no other effect takes place, if the tem-
perature be below that of boiling mercury.
The residue is yellowish-brown,  but  be-
                      17 
IRO
IRO
comes nearly black in the air; it contains
ammonia, and the iron is in such a state of
combination, that it is not affected either
by sulphuric acid or the magnet.   If this
residuum be heated still higher, then prus-
sic acid in small  quantities, and hydrogen
and azote, in the proportion of one to two,
come off,  and charcoal and metallic iron
remain.  No carbonic acid is found in this
experiment;  hence  the iron is in  the me-
tallic state in the acid.  M. Robiquet con-
cludes from  this experiment, that the pe-
culiar acid is a combination of prussic acid
and cyanuret (prusside) of iron, formed by
affinities  so  powerful,  that the poisonous
properties of the prussic acid are entirely
neutralized and lost.
   "It results," says M. Robiquet, "from
what has been said,—
   " 1. That potash is an essential element
in the white prussiate of iron.
   " 2. That the protoprussiate of iron is
slightly soluble in water, capable  of being
crystallized, and of a yellow colour.
   " 3. That  the  acid of prussian blue, and
of triple prussiates in general, is  a combi-
nation of iron, cyanogen, and prussic acid.
   " 4. That prussian blue, and the triple
prussiates in general, are formed of a cya-
nuret and a hydrocyanate (a prusside and
prussiate).
   " 5.  That it  is probable that prussian
 blue owes its colour to a certain quantity
 of water."
   These  curious  details of M. Robiquet
 have the air of chemical research, and do
 him much honour.
   I consider Mr. Porrett's process  for ob-
 taining crystallized ferroprussic acid to be
 more elegant than M. Robiquet's.  He dis-
 solved 58 gr. of crystallizeel tartaric acid
 in spirit of wine, and  poured the solution
 into a phial containing 50 gr. of ferruretted
 chyazate  of potash dissolved in 2  or 3
 drachms  of warm  water: by this process
 the whole ofthe tartaric acid will combine
 with, and precipitate the potash, in  the
 state of supertartrate of potash, and the
 alcoholic fluid will contain nothing but fer-
 ruretted  chyazic  acid, which may be  ob-
 tained from it, in small crystals,  generally
 resembling a cube, by spontaneous evapo-
 ration.—Annals of Philosophy for Septem-
 ber 1818.
    14. Protogallate, colourless, soluble.
    15. Pergallate, purple, insoluble.
    16. Prolomuriate, green  crystals,  very
  soluble.
    17. Permuriate, brown, uncrystallizable,
  very soluble. See the chlorides of iron pre-
  viously described.
    18. Protonitrate, pale green, soluble.
    19. Pernitrate,  brown,        do.
    20. Protoxalate, green prisms, do.
    21. Peroxalate, yellow, scarcely soluble.
    22. Protophosphate, blue, insoluble.
  23. Perphosphate, white, insoluble.
  24. Protosuccinute, brown crystals, solu-
ble.
  25. Persuccinate, brownish-red,  insolu-
ble.
  26. Protosulphate, green vitriol, or cop-
peras.  It is generally formed by exposing
native pyrites  to  air and moisture,  when
the sulphur and iron both absorb oxygen,
and  form the salt.  There is, however, an
excess  of sulphuric acid, which must be
saturated by digesting the lixivium of the
decomposed pyrites with a quantity of iron
plates or turnings.
  It forms beautiful green crystals, which
are transparent rhomboidal prisms,  whose
faces are rhombs with angles of  79° 50*
and 100° 10' inclined  to each other at an-
gles of 98° 37' and 81° 23'.  Sp. gr. 1.84.
Its taste is harsh  and styptic.   It reddens
vegetable blues.  Two  parts of cold and
three-fourths of boiling water  dissolve it
It does not dissolve in alcohol.   Exposure
to air converts the surface of the crystals
into  a red  deutosulphate.   A moderate
heat whitens it, by separating the water of
crystallization, and a stronger heat drives
off the sulphuric acid.  Its constituents are
 28.9 acid, 28.3 protoxide, and 45 water,
 according to Berzelius; consisting, by Mr.
 Porrett's views, of 1 prime acid + 2 oxide
-+- 7 water.
   27. Persulphate. Of this salt there  seems
to be  four or more varieties, having a fer-
 reous base, which consists, by Mr. Porrett,
 of 4 primes  iron -f- 3 oxygen = 10 in
 weight, from which their constitution may
 be learned.
   The tartrate and pertartrate  of iron may
 also be formed; or, by digesting cream of
 tartar with water on iron  filings, a triple
 salt may be obtained, formerly called tar-
 tarized tincture of Mars.
   Iron is one  of the most valuable articles
 of the materia medica.  The protoxide acts
 as a genial stimulant and tonic, in all cases
 of chronic debility not  connected with or-
 ganic  congestion or inflammation.  It is
 peculiarly efficacious in chlorosis.   It ap-
 pears to me that the  peroxide  and its com-
 binations are almost uniformly irritating,
 causing heartburn, febrile heat, and quick-
 ness  of pulse.   Many chalybeate mineral
 waters  contain  an  exceedingly  minute
 quantity of protocarbonate of iron, and yet
 exercise an astonishing power in recruiting
 the exhausted frame.  1 believe their vir-
 tue to  be derived simply  from the metal
 being oxidized to a minimum, and diffused
 by the  agency of a  mild  acid through a
 great body of water, in which state  it is
 rapielly taken up by the lacteals, and spee-
 dily imparts a ruddy hue to the wan coun-
 tenance. I find that these qualities may be
 imitated exactly, by dissolving 3 grains of
 sulphate of iron, and 60 of bicarb'—ate of 
ISI                                    IYO
potash, in a quart of cool water, with agi-
tationjjin'a'close vessel.*
  • Iron-flint.  Eeisenkiesel.— Werner.
Colours,  brown  and  red.   Massive,  and
crystallized in small equiangular six-sided
prisms, acuminated on both extremities.  It
occurs commonly in small angulo-granular
distinct  concretions.  Lustre,  vitreo-resi-
nous. Fracture small conchoidal. Opaque.
Gives sparks with  steel.  Bather difficultly
frangible.  Sp. gr. 2.6 to  2.8.  Infusible.
Its constituents are 935  silica, 5 oxide  of
iron, and 1 volatile matter.  The red iron-
flint contains 21.7 oxide of iron, and 76.8
silica.  It occurs in veins in ironstone, and
in trap-rocks, near Bristol, in the island of
Rathlin,  at Dunbar, and  in many parts of
Germany.—Jameson*
  • Isatis Tinctoria.  The plant used
for dyeing, called woad.*
   •Iskrine. Colour, iron-black. In small
obtuse angular grains.   Lustre splendent
or glistening, and metallic. Fracture con-
choidal.  Opaque. Harder than feldspar.
Brittle.   Retains its  colour in the  streak
Sp. gr. 4.6.  It melts  into a blackish-brown
glass, which is slightly attracted  by the
magnet.  The mineral acids have no effect
on it, but oxalic acid extracts  a portion of
the titanium. Its constituents are 48 oxide
of titanium, 48 oxide of iron, and 4 ura-
nium, by Dr. Thomson's  analysis  of the
iserine,  found in the  bed of the river Don,
in Aberdeenshire; but, by  Klaproth, it con-
 sists of  28 oxide of titanium, and 72 oxide
 of iron.  On the  continent it has hitherto
 been found only in the lofty Riesengebirge,
 near the origin of the  stream called  the
 Iser, disseminated in granite sand; and in
 alluvial  soil  along with pyrope in Bohemia.
 •—Jameson*
   Isinglass.  This substance  is  almost
 wholly  gelatin;  100 grains  of good  dry
 isinglass containing rather more than  98
 of matter soluble in water.
   Isinglass  is made from certain fish found
 in the Danube, and the rivers  of Muscovy.
 Willoughby and  others inform  us, that it
 is made of the sound of the  Beluga;  and
 Neumann, that it is  made ofthe Huso ticr-
 manorum, and other fish, which he has fre-
 quently seen sold in the public markets of
 Vienna.  Mr. Jackson  remarks, that  the
 Bounds  of cod, properly  prepared,  afford
 this substance; and  that the lakes  of Ame-
 rica abound with fish from which  the very
 finest sort may be obtained.
   Isinglass  receives its different shapes in
 the following manner:—
  The parts of which it is composed, par-
ticularly the sounds, are takenjfrom the fish
while sweet and fresh, slit open, washed
from their slimy sordes, divested of a very
thin membrane which envelops the sound,
and then exposed to stiffen a little in the
air. In this state they are formed into rolls
about the  thickness of a finger, and in
length according to the intended size of
the staple: a  thin membrane is generally
selected for the centre of the roll,  round
which the rest are folded alternately, and
about half an inch of each extremity of the
roll is turned  inwards.
   Isinglass is  best made in the summer, as
frost  gives  it a disagreeable colour, de-
prives it of weight,  and impairs its  gelati-
nous principles.
   Isinglass boiled in milk forms a mild nu-
tritious jelly, and is thus sometimes em-
ployed medicinally.  This, when flavoured
by the art of the cook, is the blanc-manger
of our  tables. A solution of isinglass in
water, with a very small proportion of some
balsam, spread on black silk, is the court-
plaster of the shops.
   Ivory.  The tusk, or tooth of defence of
 the male elephant.  It is an intermediate
 substance  between bone and horn,  not ca-
 pable of being softened by fire, not altoge-
 ther  so hard and brittle as  bone.  Some-
 times it grows to an enormous size, so as
 to weigh nearly two hundred pounds.
   The entire tooth is of a yellowish, brown-
 ish, and sometimes a dark-brown colour on
 the outside;  internally  white,  hollow  to-
 wards the root, and so far as was inserted
 into  the jaw, of a  blackish-brown  colour.
 The finest, whitest, smoothest,  and  most
 compact ivory comes from  the island  of
 Ceylon.  The grand consumption  of  this
 commodity is for making ornamental uten-
 sils, mathematical instruments, cases, box-
 es, balls,  combs, dice, and an infinity  of
 toys. The workmen have methods also of
 tinging it of  a variety of colours.
    Merat Guillot obtained from 100 parts of
 ivory,  24  gelatin,  64 phosphate of  lime,
 and 0.1 carbonate of lime.
    The coal of ivory is used in the arts  un-
 der the denomination of ivory-black. Par-
 ticular vessels are used in the manufactory
 of the pigment, for the purpose of render-
 ing it perfectly black.
    Some travellers  speak of the tooth  of
 the sea-horse as an excellent  ivory; but it
 is too hard to be  sawed or wrought like
 ivory.  It is used for  making artificial
 teeth. 
LAB
LAR
     KALI.  See Potash.
      Kaolin.  The Chinese name of por-
 celain clay.
   Kedria Terrestris.  Barbadoes tar.
 See Bitumen.
   • Kelp.   Incinerated  sea-weed.   See
 Soda.*
   Kermes (coccus illicis, Lin.) is an insect
 found in many parts of Asia, and the south
 of Europe.
   On account of their figure, they were a
 long  time taken for the seeds of the tree
 on which they live; whence they were call-
 ed gruins of kermes.   They also bore the
 name of vermilion.
   To dye spun worsted  with kermes, it is
 first boiled half an hour in  water  with
 bran, then two hours in  a fresh bath  with
 one-fifth of Roman alum, and one-tenth of
 tartar, to which sour  water is commonly
 added; after which it is  taken out, tied up
 in a linen bag, and carried to a cool place,
 where it is left some  days.  To obtain a
 full colour, as much kermes as equals
 three-fourths, or  even the whole of the
weight of the wool, is  put into  a warm
bath,  and the wool is put  in at the first
boiling. As cloth is more dense than wool,
either spun or in  the  fleece, it  requires
one-fourth less of the salts in the boiling,
and of kermes in the bath.
  The colour that kermes imparts to wool
has much less  bloom than the scarlet made
with cochineal; whence the latter has ge-
nerally  been  preferred,  since  the art of
heightening its  colour by means of solu-
tion of tin has been known.
  Kermes Mineral.   See Antimony.
  * Kiffekill.  See  Meerschaum.*
  * Kinate of Lime.  A salt which forms
7 per cent of cinchona. See Acid (Kinic).*
  Kino.  A few years  ago this was intro-
duced into our shops and medical practice
by the name of a gum;  but Dr. Duncan has
shown that it  is an extract.  * It contains
also a species of tamrin, whence it is used
as an astringent in diarrhoeas *
  * Klebschiefer.  Adhesive slate.*
  * Konite.  See Conite.*
  • Koumiss.   A vinous liquid, which the
Tartars make  by fermenting  mare's milk.
Something similar  is prepared in Orkney
and Shetland.*
  Kupfer Nickel.   See Nickel.
    LABDANUM.   A resin of a species of
     cistus in Candia, of a blackish colour.
The country people collect it by means of
a staff, at the end of which are fastened
many leather  thongs,  which they gently
strike on the trees.  They form it into cy-
lindrical pieces, which  are called labdanum
in tortis.  It is greatly adulterated by the
addition of black sand.  It has been  used
in cephalic and  stomachic  plasters and
perfumes.
  Laboratory.  A place properly fitted
up for the performance of chemical opera-
tions.
  As chemistry is a science founded en-
tirely on experiment, we  cannot hope to
understand it  well, without  making  such
experiments as verify most  of the  known
fundamental operations, and also such  as
reasoning, analogy, anel the spirit of inqui-
ry, never fail to suggest to  those, whose
taste and suitable talents leael them to this
essential part of experimental philosophy.
Besides, \\\\en a person himself observes,
and  operates,  he  must perceive, even in
the most common  operations, a great vari-
ety of small facts,  which must necessarily
be known,  but which  are not mentioned
either in books or in memoirs, because they
are too numerous, and would appear too
minute.  Lastly, there are many qualities
in the several agents, of which no just no-
tion can be given by writing, and which
are perfectly well known as soon as they
have been once made to strike our senses.
   Many people think, that a laboratory le-
vel with the ground is most convenient, for
the sake of water, pounding, washing, &c.
It certainly has these advantages; but it is
also subject  to very  great  inconvenience
from moisture.
   Constant moisture, though not very con-
siderable and sensible in many respects, is
a very great inconvenience in a chemical
laboratory.  In such  a place, most saline
matters become moist in time, and the in-
scriptions fall off, or are  effaced;  the bel-
lows rot;  the  metals rust; the  furnaces
moulder, and every  thing  almost spoils.
A  laboratory, therefore,  is more advan-
tageously placed  above   than below the
ground, that  it may be as dry as possible.
The air must have free access to it; and it
must  even be so  constructed,  that, by
means of two or more opposite openings,
a current of air may be admitted, to carry
off any noxious vapours or dust.
  In the laboratory a chimney ought to be
constructed, so high that a person may ea-
sily stand under it, and as extensive as is 
LAB                                 LAB
 possible; that is, from one wall to another.
 The funnel of this chimney ought to be as
 high as is possible, and sufficiently con-
 tracted to make a good draught.  As char-
 coal only is burnt  under this chimney, no
 sor.t is  collected in it; and therefore it need
 not be so  wide as  to  allow  a chimney-
 sweeper to pass up into it.
   Under this chimney may be constructed
 some brick furnaces, particularly a melting
 furnace, a  furnace for  distilling with an
 alembic,  and one  or two ovens like  those
 in kitchens.  The  rest of the space ought
 to be  filled up  with stands  of  different
 heights, from a foot to a foot and a half,
 on which portable  furnaces of all kinds are
 to be placed. These furnaces are the most
 convenient, from the facility of disposing
 them at pleasure;  and they are the only
 furnaces which are necessary in a small la-
 boratory.  A double pair of bellows of mo-
 derate  size must also be placed as commo-
 diously under the  chimney,  or as near as
 the place will allow.  These  bellows  are
 sometimes  mounted in a portable frame;
 which  is sufficiently convenient when the
 bellows are not more than 18 or 20 inches
 long.   These bellows ought to have a pipe
 directed toward the hearth where the forge
 is to be placed.
   The  necessary furnaces are, the simple
 ftirnace, for distilling with a copper  alem-
 bic; a lamp furnace; two reverberatory fur-
 naces of different sizes, for distilling with
 retorts; an  air or  melting furnace,  an es-
 say furnace, and a  forge furnace.
   Under  the chimney,  at  a convenient
 height, must be a row of hooks driven in-
 to the back and side walls; upon which are
 to be hung small shovels; iron pans; tongs;
 straight, crooked, and circular pincers;  po-
 kers; iron rods, and other utensils for dis-
 posing  the fuel and  managing the  cruci-
 bles.
   To the walls of the laboratory ought to
 be fastened shelves of different breadths
 and heights; or these shelves may be sus-
 pended by hooks.  The shelves are to con-
 tain glass vessels, and the products of ope-
 rations, and ought  to be in as great a num-
 ber as is possible.  In a laboratory where
 many experiments  are made, there cannot
 be too many shelves.
  The most convenient place for a stone or
 leaden cistern, to contain water, is a corner
 of the laboratory, and under it a sink ought
 to be placed with a pipe, by which the wa-
ter poured into it may discharge itself.  As
 the vessels are always  cleaned under this
cistern,  cloths and bottle brushes ought to
be hung upon hooks fastened in the  walls
near it.
  In the middle of the laboratory a large
table is  to be placed, on  which  mixtures
are to  be  made, preparations for opera-
tions, solutions, precipitations, small nitra-
 tions; in a word, whatever does not require
 fire, excepting that of a lamp.
   In convenient parts of the laboratory are
 to be placed blocks of wood upon mats; one
 of which is to support a middle-sized iron
 mortar;  another to support a middle-sized
 marble, or rather hard stone mortar; a third
 to support an anvil.   Near the mortars are
 to be hung searces  of different  sizes and
 fineness;anel near the anvil, a hammer, files,
 rasps, small pincers, scissars,  sheers, and
 other small utensils, necessary to give me-
 tals a form proper for the several operations.
   Two moveable trestles ought to  be in a
 laboratory, which may serve to  support a
 large filter mounted upon a frame, when
 it is required.  This apparatus is removed
 occasionally to the most convenient place.
   Charcoal  is an important article in a la-
 boratory, and it therefore must  be placed
 within reach; but as the black dust which
 flies about it, whenever it is stirred, is apt
 to soil every thing in  the laboratory, it had
 better be in some place  near the  labora-
 tory; together with some furze, which is
 very convenient for kindling fires quickly.
 This place serves,  at the same  time,  for
 containing bulky things, which are not of-
 ten wanted; such as furnaces, bricks, tiles,
 clay, fire-clay, quicklime, sand, and  many
 other things necessary for chemical opera-
 tions.
   Lastly, a middle-sized  table, with solid
 feet, ought to be enumerated among  the
 large moveables of a laboratory, the  use
 of which is to support a porphyry, or levi-
 gating stone, or rather  a very  hard and
 dense  grit-stone, together with a muller
 made of the same kind of stone.
   The other small  moveables or utensils
 of a laboratory are, small hand mortars of
 iron, glass, agate, and Wedgwood's ware,
 and their pestles;  earthen, stone, metal,
 and glass vessels, of  different kinds, fun-
 nels, and measures.
   Some white writing paper, and some un-
 sized paper for filters; a  large number of
 clean straws,  eight or ten inches long, for
 stirring mixtures in glasses, and for sup-
 porting paper filters placed in glass fun-
 nels.
  Glass tubes for stirring and mixing cor-
 rosive liquors; spatulas of wood, ivory, me-
 tal, and glass.
  Thin pasteboards, and  horns,  very con-
 venient for collecting  matters bruised with
 water upon the levigating stone, or in mor-
 tars; corks of all sizes; bladders and linen
 strips for luting vessels.
  A good portable pair of bellows; a good
 steel for  striking fire; a glue-pot, with its
 little brush; lastly, a great many boxes, of
 various sizes, for containing most of  the
 above-mentioned things,  and which are to
be placed upon the  shelves.
  Besitle  these  things,  some  substances 
LAB                                   LAR
are so necessary in most chemical opera-
tions, that they may be  considered  as  in-
struments requisite for the practice of this
science.  These substances are called  re-
agents, which see under Ores (Analy-
sis of), and Waters (Mineral).
  All metals, which ought to be very pure.
  A person provided with such instruments
and substances, may at once perform many
chemical experiments.
  The general observations of  Macquer
upon the conducting of chemical processes,
are truly valuable and judicious.  Method,
order, and cleanliness,  are essentially  ne-
cessary in  a  chemical laboratory.  Every
vessel and utensil ought to be well cleansed
as often as it is used, and  put again into
its  place: labels ought to be put upon  all
the substances.  These  cares, which seem
to be trifling, are however  very  fatiguing
and tedious; but they  are also very impor-
tant,  though  frequently  little observed.
When a person is keenly engaged, experi-
ments succeed each  other  quickly,  some
seem nearly to decide the  matter, and
others suggest new ideas;  he cannot but
proceed to them immeeliately,  and  he is
led from one to another: he thinks he shall
easily know again the products ofthe first
experiments, and therefore he does not take
time to put them in order: he prosecutes
with eagerness the experiments which  he
has last thought of; and in the mean time,
the vessels employed, the glasses and bot-
tles filled,  so accumulate, that  he  cannot
any longer distinguish them; or  at  least,
he  is  uncertain  concerning many  of  his
former products.  This evil is  increased,
if a new series of operations succeed, and
occupy all the laboratory; or if he be obliged
to quit it for some time, every thing then
goes into confusion.   Thence it frequently
happens, that  he loses the  fruits  of much
labour, and that he must throw away  al-
most all the products of his experiments.
  WThen new  researches and inquiries  are
made, the mixtures, results, and products
of  all the operations  ought to  be kept  a
long time, distinctly labelled and register-
ed; for these things, when kept some time,
frequently present phenomena, that were
not at all suspected.  Many fine discove-
ries in chemistry have been made in this
manner; and many have certainly been lost
by throwing away too  hastily, or neglecting
the products.
  Since chemistry offers  many  views  for
the improvement of many important arts; as
it presents prospects of many useful  and
profitable discoveries; those who apply their
labours in this way ought to be exceedingly
circumspect, not to be  led into a useless
expense of money and time. In a  certain
set of experiments, some one is generally
of  an  imposing appearance, although in
reality it is nothing more. Chemistry  is
full of these half successes, which  serve
only to deceive the unwary, to multiply the
number of trials, and to lead to great ex-
pense before the fruitlessness of the search
is discovered.  By these reflections we do
not intend to divert from all such research-
es, those  whose taste  and talents render
them fit for them; on the contrary, we  ac-
knowledge, that the improvement  of the
arts, and the discovery of new objects of
manufacture and commerce, are undoubt-
edly the finest and most  interesting part
of chemistry, and which make that science
truly valuable; for without these ends, what
would chemistry be but a science purely
theoretical, anel capable of employing only
some abstract and  speculative minds, but
useless to society? We  acknowledge also,
that the successes in this  kind of chemical
inquiry are not rare; and that their authors
have sometimes acquired fortunes, so much
the more honourable, as being the fruits of
their talents and industry. But we repeat,
that, in these researches, the more dazzling
and near any success appears, the more
circumspection, and even distrust is  ne-
cessary.  See Analysis, Attraction,
Balance.
   The plates annexed, with the following
explanations of them, will give the student
an idea of a large variety of the most use-
ful and necessary  articles of a chemical
apparatus.
   Plate II. fig. 1.   Crucibles or pots, made
either of earth, black  lead, forged iron, or
platina.   They are used for  roasting, cal-
cination,  and fusion.
   Fig. 2.   Cucurbits, matrasses, or bodies,
which are glass, earthen,  or metallic ves-
sels, usually of the shape of an egg, and
open at top.   They serve the purposes of
digestion, evaporation, &.c.
   Fig. 3.  Retorts are globular vessels of
earthen ware, glass, or metal, with a neck
bended on one  side.   Some  retorts have
 another neck or opening at their upper
 part, through which they may be charged,
 and the opening may be afterwards closed
 with a stopple.  These are called tubulated
 retorts.   A Welter's tube of safety may be
 inserted in this opening, instead of a stop-
 ple.  See Plate VII. fig. 1. b and e.
   Receivers are vessels,  usually of glass,
 of a spherical form, with a straight neck,
 into which the neck of the retort  is usu-
 ally inserted.  When any proper substance
 is put into a retort, and heated, its volatile
 parts pass over  into the  receiver,  where
 thev are  condensed.   See fig. 5. and Plate
 V. fig. 2. k.
   Fig. 4.  The alembic is used for distil-
 lation, when the products are too  volatile
 to admit ofthe use of the last mentioned
 apparatus. The alembic consists of a body
 a, to which is adapted a head b. The head
 is of a conical figure,  and has its external 
LAB
LAB
circumference  or base  depressed lower
than its neck, so that the vapours which
rise, and  are condensed against its sides,
run down into the circular channel formed
by its depressed part, from  whence  they
are conveyed by the nose or beak c, into
the receiver d.  This instrument is less
simple than the retort, which certainly may
be used for the  most  volatile products, if
care be taken to apply a  gentle  heat  on
such occasions.  But the alembic has  its
conveniences.  In particular the residues
of distillations may be easily cleared  out
of the body a; and in experiments of sub-
limation,  the head is very  convenient to
receive the dry products, while the more
volatile and elastic parts pass over into the
receiver.
   Fig. 6.   Represents the large stills used
in the  distillation of ardent spirits,  a re-
presents  the  body, and b the head, as be-
fore.  Instead  of using a refrigeratory or
receiver,  the spirit is made to pass through
a spiral pipe called the worm,  which is
immersed in a tub of cold water d. During
its passage it is condensed, and comes out
at the  lower extremity, e, of  the pipe, in a
fluid form.
   The manner in which the excise laws for
Scotland were formed, rendering it advan-
tageous to the  distillers in that country to
have stills of small capacity, which  they
could work very quickly,  their ingenuity
was excited to contrive  the  means of ef-
fecting this.  It was obvious, that a shal-
low still,  with a broad bottom  completely
exposed to a strong heat, would best an-
swer the purpose; and this was brought to
such perfection, that a still of the capacity
of 40 gallons in the body, and three in the
head,  charged  with  16  gallons of wash,
could be worked 480 times  in 24 hours.
Fig. 7. is  a vertical section of this still, a
the bottom, joined to b, the shoulder, with
solder, or rivets, or screws  and lute,  c,
the turned-up edge of the bottom, against
which,  and on a level with a, the brick-
work of the coping of the flue  rests, pre-
venting the flame from getting up to touch
c.   d, the discharge pipe,  e e, the body of
the still,  f, section  of the central steam
escape pipe,  g, section of one of the late-
ral steam  escape pipes; A, outside view of
another,   i i i i, inferior apertures of lateral
steam  pipes; kkkk, their superior  aper-
tures.   /  /,  bottom scraper, or agitator,
which, may either be  made to apply close
to  the bottom, or to drag chains; m,  the
upright shaft of this engine, as it is called;
n the horizontal wheel with its supporters.
o,  its vertical  wheel, p,  its handle and
shaft; n, support of the shaft,  r, froth and
ebullition jet-breaker, resting on the  cross
bar *.   t, its  upright shaft,  u, its  cup-
mouthed collar, filled with wool and grease,
and held down by a plate and screws,  v,
general steam escape pipe, or head.   The
charge  pipe, and the sight hole,  for the
man who charges it to see when it is suffi-
ciently full, are not seen in this view.
  The best construction of a furnace has
not been well ascertained from experience.
There are  facts  which show, that a fire
made on  a grate near  the  bottom of a
chimney, of equal width throughout, and
open both above and below, will produce a
more intense heat than  any other furnace.
What mny be the limits for the height of
the chimney is not ascertained from any
precise trials; but thirty times its diameter
would not  probably be too high.  It seems
to be an advantage to contract the diameter
of a chimney, so as to make it smaller than
that of  the fire-place, when no other air is
to go up the chimney than what has passed
through the fire;  and there is no prospect
of advantage to  be  derived  from widen-
ing it.
  Plate V. fig. 3.  exhibits the wind or air-
furnace for melting,  a  is the  ash-hole, /
an opening for the air.  c is the fire-place,
containing a covered crucible, standing on
a support of baked earth, which rests on
the  grate,  d is  the passage  into e, the
chimney.   At d a shallow crucible or cu-
pel may be placed in the current of the
flame,  and at a? is an earthen or stone co-
ver, to  be  occasionally taken  off for the
purpose of supplying the fire with fuel.
  Fig. 2. is a reverberatory furnace,  a a
the ash-pit and fire-place,   bb body ofthe
furnace,  c c dome, or  reverberating roof
of the furnace,   dd chimney,  ee door of
the ash-pit.  // door of the fire-place, gg
handles of the body,  h aperture to admit
the head of the retort,  ii handles of the
dome.   Ar receiver.  II stand  of the recei-
ver,  m m retort,  represented in the body
by dotted lines.
  Another reverberatory furnace, a little
differing in figure, may be seen in Plate 1.
fig. 2.
  M. Chenevix has constructed a wind fur-
nace, which is in  some respects to be pre-
ferred to  the usual  form.  The sides, in-
stead of being perpendicular,  are inverted,
so that the hollow space is  pyramidical.
At  the  bottom the opening  is 13 inches
square, and at the top but eight. The per-
pendicular height is 17 inches.  This form
appears to unite the following advantages:
1st,  A great surface is exposed to the air,
which  having  an easy  entrance, rushes
through the fuel  with great  rapidity; 2d,
The inclined sides act in some measure as
reverberating surfaces; and 3d, The  fuel
falls of  itself, and is always in close  con-
tact with the crucible placed near the grate.
The late Dr. Kennedy of Edinburgh, whose
opinion  on this subject claims the greatest
weight, found that the  strongest  heat in
our common wind furnaces was within two 
                  LAB

 or three inches of the grate.  This, there-
 fore, is the most advantageous position for
 the crucible, and still more so when we can
 keep it surrounded with fuel.  It is incon-
 venient, and dangerous for the crucible, to
 stir the fire often to make the fuel fall, and
 the pyramidical form  renders this unneces-
 sary.  It is also more easy to  avoid a sud-
 den  bend in the chimney, by the upper part
 of the furnace advancing as  in this  con-
 struction.  In plate V.  fig. 1.  a is a grate;
 e and c are two bricks, which  can be let in
 at pleasure to diminish the capacity; b is
 another grate, which can be  placed  upon
 the bricks  c and c for smaller purposes; d
 and d are bricks which can be placed  upon
 the grate b to diminish the upper capacity,
 so that, in fact,  there are four  different
 sizes in the same furnace.   The  bricks
 should all  be ground down to the slope of
 the furnace, and fit in with tolerable^accu-
 racy.  They are totally independent of the
 pyramidical form of the furnace.
  Mr. Aikin's  portable blast furnace  is
 composed of three parts, all  made  out of
 the common thin  black lead melting  pots,
 9old in London  for the use of the gold-
 smiths.   The lower piece c, fig. 6. is the
 bottom of one of these pots, cut off so low
 as only to leave a cavity of about an inch
 deep, and ground  smooth above and below.
 The  outside diameter, over the top, is five
 inches and a half.  The middle-piece or
fire-place a, is a larger portion of a similar
pot,  with a cavity about six inches deep,
 and measuring seven inches and a half over
the top, outside diameter,  and perforated
 with six blast holes at the bottom.  These
 two pots are all that are essentially neces-
 sary  to the furnace for most operations;
 but when it is wished to heap up fuel above
 the top  of a crucible contained,  and espe-
 cially to protect the eyes from the intolera-
 ble glare of the fire when in full height, an
 upper pot b is  added, of the  same dimen-
 sions as the middle one, and  with a large
 opening in the side,  cut to allow the exit
 of the smoke and flame.  It has also an iron
 stem, with  a wooden handle (an old chisel
 answers the purpose very well) for remov-
 ing it occasionally.   The  bellows, which
 are double  (d), are firmly fixed, by  a  little
 contrivance which will take off and on, to
 a heavy stool, as represented  in the plate;
 and their handle should be  lengthened so
 as to make them work easier  to the hand.
 To increase their force, on particular occa-
 sions, a plate of lead may be firmly tied on
 the wood of the upper flap.   The  nozzle
 is received into a hole in the pot c, which
 conducts the blast into its cavity. Hence the
 air passes into the fire-place a, through six
holes of the size of a  large gimlet, drilled
 at equal distances through the bottom of
the pot, and all converging in an inward di-
rection, so  that, if prolonged, they would
                LAB

meet about the centre of the upper part <rf
the fire.  No luting is  necessary  in  using
this furnace, so that it may be set up and
taken down immediately.  Coak, or com-
mon cinders, taken from the fire when the
coal ceases to blaze, sifted from  the dust,
and broken into very small pieces,  forms
the best fuel  for higher heats.   The fire
may be kindled at first by a few lighted
cinders, and a small quantity of wood char-
coal.  The  heat which this little furnace
will afford  is so intense, that its power was
at first discovered accidentally by the fu-
sion of a thick piece of cast iron.  The ut-
most heat procured by it was 167 degrees
of Wedgwood's pyrometer, when a Hessian
crucible  was  actually  sinking  down in a
state of porcelaneous fusion.   A steady
heat of 155* or 160° may be depended on,
if the fire  be properly  managed,  and the
bellows worked with vigour.
  The process of cupellation may be exhi-
bited in a lecture, or performed  at  other
times, by means of this furnace.  The me-
thod consists  in causing a portion of the
blast to be diverted from the fuel, and  to
pass through a crucible in which the cupel
is placed.  This arrangement supplies air;
and the whole may be seen by a sloping
tube, run through  the  cover  of the  cruci-
ble.
  Charcoal is  the material most commonly
used  in furnaces.  It produces  an intense
heat  without  smoke,  but it  is consumed
very  fast.   Coak or charred pit-coal pro*
duces a very strong and lasting heat. Nei-
ther of these produces a strong heat at a
distance from  the  fire.  Where the action
of flame is required, wood or coal must be
burned. Several inconveniences attend the
use of coal, as its fuliginous fumes, and its
aptitude to stop the passage of air by be-
coming fused.  It  is useel, however,  in the
reverberatory furnaces of glass-houses, and
is the best material where vessels are to be
supplied with  a great quantity of heat at no
great intensity, such as in distilleries, &c.
  Frequently, however, the flame of an Ar-
gand lamp  may be employed very conve-
niently for chemical purposes.  PI. VI. fig.
2. is a representation of a lamp furnace, as
it is perhaps  not  very properly called,  as
improved by Mr. Accum.   It consists of a
brass rod screwed to  a  foot of the same
metal, loaded with  lead.   On this rod,
which may be unscrewed in the middle
for rendering  it more portable,  slide three
brass sockets with straight arms, termina-
ting in brass rings of different diameters.
The largest measures  four inches  and a
half.   These  rings serve  for  supporting
glass alembics, retorts, Florence flasks,
evaporating basins, gas bottles,  &c;  for
performing  distillations, digestions, solu-
tions, evaporations, saline fusions, concen-
trations, analyses with the pneumatic appa- 
LAB                                   LAB
 ratus, fee.  If the vessels require not to be
 exposed to the naked fire, a copper sand-
 bath may  be interposed, which is to be
 previously placed in  the ring.  By means
 of a thumb-screw acting on the rod of the
 lamp, each of the  brass rings  may be set
 at different  heights,  or turned aside, ac-
 cording to the pleasure ofthe operator.  Be-
 low these  rings is a  fountain-lamp on Ar-
 gand's plan, having a  metallic valve within,
 to prevent the oil from  running out while
 the reservoir is put into its place.   This
 lamp also slides on the  main brass rod by
 means of a socket and ihumb->screw.  It is
 therefore easy to bring it nearer, or to move
 it further, at pleasure, from the vessel, which
 may remain fixed; a circumstance which,
 independent ofthe elevation and depression
 ofthe wicks ofthe lamp, affords the advan-
 tage of heating the vessels by degrees after
 they are duly placed,  as well as of augment-
 ing or diminishing the heat instantly; orfor
 maintaining it for several hours at a certain
 degree, without in the least disturbing- the
 apparatus suspended over it. It may there-
 fore be used for producing the very gentle
 heat necessary for the  rectification of ethers,
 or the strong heat requisite for distilling
 mercury.  The chief improvement of this
 lamp consists in its power of affording an
 intense heat by the addition of a second cy-
 linder, adeledto that ofthe common lamp of
 Argand.  This additional cylinder encloses
 a wick of one inch and a half in diameter,
 and it is by this ingenious contrivance, which
 was first suggested by Mr.  Webster, that a
 double flame is caused, and more than three
 time the heat  of an Argand's lamp of the
 largest size is produced.
   Every effect of the most violent heat of
 furnaces may be produced by the flame of a
 candle or lamp, urged upon a small particle
 of any substance, by the blow-pipe.  This
 instrument is sold by the ironmongers, and
 consists merely of a brass pipe about one-
 eighth of an inch diameter at one end, and
 the other tapering to a much less size, with
 a very small perforation for  the  wind to
 escape  The smaller end is bended on one
 side.  For philosophical or other nice pur-
 poses the blow-pipe is provided with a bowl
 or enlargement a (PI. V. fig. 5.), in which
 the vapours of the breath are conelensed
 and detained, and also  with three or four
 small nozzles, b, with different apertures, to
 be slippeel on the smaller extremity. These
 are of use when larger or smaller flamesare
 to be  occasionally used, because a larger
 flame  requires a large  aperture, in  order
 that the air may effectually urge  it upon
the matter under examination.
   There is an artifice in the blowing  through
this pipe, which is more difficult to describe
than to acquire. The  effect intended to be
produced is a  continual stream of air for
many minutes, if necessary, without  ceasing.
 This is done by applying the tongue to the
       Voir. II'.
roof of the mouth,  so as to interrupt the
communication between the mouth and the
passage ofthe nostrils; by which means the
operator  is  at liberty to breathe through
the nostrils,  at the  same time tha.  by the
muscles of ihe lips he forces a continual
stream of air from the anterior part of the
mouth through the blow-pipe.  \\ hen the
mouth begins to be empty, it is replenished
by the lungs in an instant, while the tongue
is withdrawn from  the roof of the mouth,
and replaced again in the same manner as in
pronouncing the monosy liable tut.   In this
way the stream may be continued for along
time without any fatigue, if the flame be not
urged too impetuously, and even in this case
no other fatigue is felt than that of the mus-
cles ofthe lips.
  A wax  candle, of a moderate  size, but
thicker wick than they are usually made
with,  is the most convenient  for occasional
experiments; but a tallow candle will do
very well.    The  candle should be snuffed
rather short, and the wick turned on one
side toward the object, so thai a part of it
should lie horizontally.   The stream of air
must be blown along this horizontal part, as
near as may  be without striking the wick.
If the flame be ragged and irregular, it is a
proof, that the hole is not round or smooth;
and if the flame have a cavity through it, the
aperture ofthe pipe is too large.  When the
hole is of a proper  figure and duly propor-
tioned, the flame consists of a neat luminous
blue cone, surrounded by another flame of
a morefaint and indistinct appearance. The
strongest heat  is at the point of the innex
flame.
  The body intended to be acted on by the
blow-pipe ought not to exceed the size of a
peppercorn.  It may be  laid upon a piece
of close-grained, well- burned charcoal; un-
less it be of such a nature as to sink into the
pores of this substance, or to have its pro-
perties affected by its inflammable quality.
Such bodies may be placed in a small spoon
made of pure gold or silver, or platina.
  Many advantages may  be  derived from
the use of this simple and valuable instru-
ment.  Its smallness, which renders it suit-
able to the pocket, is no inconsiderable re-
commendation.   The most expensne ma-
terials, and the minutest specimens of bo-
dies, may be used  in these experiments ;
and the whole process, instead of being car--
ried on in an opaque vessel, is under the eye
ofthe observer from beginning to end.  It
is true, that very little can be determined in
this way concerning the quantities of pro-
ducts; but,  in most cases, a knowledge  of
the contents of any substance is a great ac-
quisition, which is thus obtained in a very
short time,  and will at all events serve to
show the best and least expensive way  of
conducting processes with the same matters
in the larger way.
  The blow-pipe has deservedly oflate year*
            IS 
LAB
LAB
 been considered as an essential instrument
 in a chemical  laboratory, and several at-
 tempts have been made to facilitate its use
 by the addition of bellows, or some other
 equivalent instruments.  These are doubt-
 less very convenient, though they render it
 less portable for mineralogical researches.
 It will not, here, be necessary to enter into
 any description of a pair of double bellows
 fixed under a table,  and communicating
 with a blow-pipe which passes through the
 table.  Smaller bellows, of a portable size
 for the pocket, have been made for the same
 purpose.  The ingenious chemist will find
 no great difficulty in adapting a bladder to
 the blow-pipe, which, under the pressure
 of a board, may produce a constant stream
 of air, and may be replenished, as it becomes
 empty, by blowing into it with bellows, or
 the mouth, at another  aperture furnished
 with a valve opening inwards.
   The chief advantage these  contrivances
 have over  the common blow-pipe is, that
 they may be filled with oxygen gas, which
 increases the activity of combustion to an
 astonishing degree.  The vapour from al-
 cohol has likewise been employed,  and an
 ingenious contrivance for this purpose by
 Mr. Hooke is represented, Pi.  V. fig. 4. a is
 a hollow sphere for containing alcohol, rest-
 ing upon a shoulder in the ring  o.  If the
 bottom be made flat instead  of spherical,
 the action ofthe flame will then be greater.
 * is a bent  tube with  a jet at the end, to
 convey the alcohol  in the state of vapour
 into the flame at q; this tube is continued in
 the inside up to e, which admits of a being
 filled nearly, without any alcohol running
 over,  d is a safety valve, the pressure  of
 which is determined at pleasure, by screw-
 ing higher or lower on the pillar e, the two
 milled nuts / and g carrying the steel arm
 h, which rests on the valve.  *' is an opening
 for putting in the alcohol.  *■  is the lamp,
 which adjusts to different distances from a,
 by sliding up or down the two pillars I I.
 The distance ofthe flame q from  the jet is
 regulated by the pipe which holds the wick
 being a little removed from the  centre ofthe
 brass piece m, and of course revolving in a
 circle,  n the mahogany stand.
 ■ For the various habitudes of bodies when
 examined by the blow-pipe, see Blow-pipe.
  Little need be said concerning the man-
 ner of making experiments with fluid bodies
in the common temperature of the atmos-
phere.  Basins, cups, phials, matrasses, and
other similar vessels, form the  whole appa-
ratus required for the purpose of containing
the matters intended to be put together ;
and no other precaution or instruction is re-
quired, than to use a vessel of such materials
as shall not be corroded or acted upon by its
contents, and of sufficient capacity to admit
of any sudden expansion or frothing of the
 fluid, if  expected.  This  vessel must be
 placed in a current of air, if noxious fume*
 arise, in order that these may be blown
 from the operator.
   The method of making experiments with
 permanently elastic fluids, or gases, though
 simple, is not so  obvious.   We  live  im-
 mersed in an atmosphere not greatly differ-
 ing in density from these fluids, which for
 this reason are not sufficiently ponderous to
 be detained in open vessels by their weight.
 Their remarkable levity, however, affords a
 method of confining them by means of other
 denser  fluids. Dr. Priestley, whose labours
 so far exceeded those of his predecessors
 and  contemporaries,  both  in  extent and
 importance,  that he may with justice be
 styled the father of this important branch of
 natural philosophy, used the following ap-
 paratus.
   PI. VI. fig. 1.  a represents a wooden ves-
 sel or tub; k, k,  k, is. a shelf fixed in the tub.
 When  this apparatus is used, the tub  is to
 be filled with water to  such a height,  as to
 rise about one inch above the upper surface
 of the shelf,  b, g, f, are glass jars inverted
 with their mouths downward, which rest
 upon the shelf.  If these, or any other ves-
 sels open only at one end, be plunged under
 the water, and inverted after they are filled,
 they will remain full, notwithstanding their
 beingraised out ofthe water, provided their
 mouths be kept immersed; for in this case,
 the water is sustained by the pressure of the
 atmosphere, in the same manner as the  mer-
 cury in the barometer.  It may without
 difficulty be imagined,  that if common air,
 or any other  fluid resembling common air
 in lightness and  elasticity, be suffered to en-
 ter these vessels, it will rise to the upper
 part, and the surface of the water will  sub-
 side. If a bottle, a cup, or any other vessel,
 in that state which is usually called empty,
 though  really full of air, be plunged into the
 water with  its  mouth downwards, scarce
 any water will enter, because its entrance is
 opposed by  the  elasticity of the  included
 air; but if the vessel be turned up, it im-
 mediately fills,  and the air rises in one or
 more bubbles to the surface.  Suppose this
 operation to be performed under one of the
jars which are filled with water, the air will
 ascend as before; but instead of escaping, it
 will be detained  in the upper part of the
jar. In this manner, therefore, we see, that
air may  be emptied out of one vessel into
 anotherby an inverted pouring, in which the
air is made to ascend from the iower vessel i
to theupper§-, in which  the experiments are
performed, by the action of the weightier
fluid, exactly similar to the common pouring
 of denser fluids, detained in the bottoms of
 open vessels, by the simple action of gravity.
When the receiving vessel  has a narrow
 neck, the air may  be poured through a
glass funnel h.
   c (Ibid.) is a glass body or bottle, the bot- 
LAB                                   LAB
torn of which is blown very thin, that it may
support the  heat of a candle suddenly ap-
plied, without cracking. In its neck isfitted,
by grinding, a tube d, curved neatly  in the
form ofthe letter s.  This kind of vessel is
very useful in various chemical operations,
for which it will be convenient to have them
of several sizes.  In the figure, the body c is
represented as containing a fluid, in the act
of combining with a substance that gives out
air, which passes through the tube into the
jar b, under the mouth  of which the other
extremity of the tube is placed.  At e is a
small retort of glass or earthenware, the
neck of which being plunged in the water,
beneath die jar /, is supposed to  emit the
elastic fluid, extricated from thecontentsof
the retort, which is received in the jar.
   When any thing, as a gallipot, is to be
supported at a considerable height within  a
jar, it is convenient to have such wire stands
as  are  represented fig. 3.  These answer
better than any other, because they take up
but little room, and are easily bent  to any
figure or height.
   In order to expel air from solid substances
by means of heat,  a gun-barrel, with the
touch-hole screwed up and  rivetted, may be
used instead of an iron retort.   The subject
may be placed in the chamber of the barrel,
and the rest of the bore may be filled with
dry sand, thathas been well burned, to expel
whatever air it might have  contained. The
stem of a tobacco-pipe, ora  smallglass tube,
being luted in the orifice of the barrel, the
other extremity must  be put into the fire,
that the heat may expel the air from its con-
tents.  This air will of course pass through
the tube, and may be received under an in-
verted vessel, in the usual manner.
   But the most accurate method of procur-
ing air from several substances by means of
heat, is to put them, if they will bear it, into
phials full of quicksilver, with the mouths
inverted in the same, and  then throw the
focus of a burning lens or mirror upon them.
For this purpose, their bottoms should be
 round  and very thin, that they may not be
liable to fly with the sudden application of
heat.  The body c, Pi. VI. fig. 1. answers
 this purpose very well.
   Many kinds of air combine with water,
and therefore require to be treated in an ap-
 para' us, in which quicksilver is made use of.
 This fluid being very  ponderous,  and of
considerable price, it is an  object of conve-
 nience, as well as economy, that the trough
 and vessels should be smaller than when
 water is used.  See PL VII. fig. 1.//.
   When trial is to be  made of any kind of
 air, whether it be fit for maintaining com-
 bustion, the air may be put into a long nar-
 row glass vessel, the mouth of which, being
 carefully covered, may be  turned upward.
 A bit of wax candle being then fastened to
 • he end of a wire, which is bent so that the
flame of the candle may be uppermost, is
to be letdown into the vessel, which must
be kept covered till the instant of plunging
the lighted candle into the air.
  Where the change of dimensions, which
follows from the mixture of several kinds of
air, is to be ascertained, a graduated narrow
cylindrical vessel may be made use of. The
graduations may be made by  pouring in
successive equal measures of water into this
vessel, and marking its surface at each ad-
dition.  The measure may be afterward
used for the different kinds of air, and the
change of dimensions will be shown by the
rise or fall of the mercury or water in th<s
graduated vessel.  The purity of common
air being determinable  by the diminution
produced by the addition  of nitric oxide
gas, these tubes have been called eudiome-
ter tubes.
   Some  substances, more especially pow-
ders, cannot conveniently be put into aphi-
al, or passed through a fluid.  When air is
to be  extricated from, or added to  these,
there  is  no better method, than to place
them on a stand under the receiver of the
air-pump, and exhaust the common air, in-
 stead of excluding it by water or mercury.
 This process requires a good air-pump, and
 careful management, otherwise the common
 air will not be well excluded.
   It is frequently  an interesting object, to
 pass the  electric  spark through different
 kinds  of air, either alone or mixed together.
 In this case a metallic wire may be fastened
 in the upper end of a tube, and the sparks
 or shock may be passed through this wire
 to the mercury or water used to confine the
 air.  If there be reason to apprehend, that
 an expansion  in the air  may remove the
 mercury  or water beyond the striking dis-
 tance, another wire may be thrust up to re-
 ceive the electricity, or two wires may  be
 cemented into opposite holes in the sides of
 an hermetically sealed tube. Holes may  be
 made in glass, for this and other chemical
 uses, by a drill of copper or soft iron, with
 emery and water; and  where this  instru-
 ment is wanting, a small round file with wa-
 ter will cut a notch in small vessels, such as
 phials or tubes, though with some danger
 of breaking them.  In some electrical ex*
 periroentsof the kind here mentioned, there
 is reason to expect a fallacious result from
 the wires being burned by the explosion or
 spark.  For this reason, the electricity may
 be made to pass through the legs of a  sy-
 phon, containing the air which is under con-
 sideration in the upper part of its curvature.
 One ofthe vessels, in which the legs ofthe
 syphon  rest, must therefore be insulated;
 and if any watery fluid be used to confine
 the air,  it is  generally supposed that  no
 combustion takes place.
    It is sometimes desirable to impregnate
 water for medicinal purposes with some gas, 
LAB
LAB
 as the carbonic acid, and for this the appa-
 ratus of Dr. Nooth is very effectual and con-
 venient.  It consists of three glass vessels,
 Pi. VI. fig. 4.  The lower vessel c contains
 the effervescent materials;  it has a small ori-
 fice at (/.stopped with a ground stopper, at
 which an additional supply of either acid or
 water, or chalk, may be occasionally intro-
 duced.  The middle vessel b is open, both
 above and below.  Its inferior neck is fitted
 by grinding into the neck  h of the  lower
 vessel, in the former is a glass valve, form-
 ed by  two pieces  of tube, and a plano-con-
 vex lens, which is moveable, between thein,
 as represented in fig. 5.  This  valve opens
 upwards, and suffers the air to pass;  but
 the water cannot return through the tubes,
 partly because the orifice is capillary, and
 partly because the flat side ofthe lens covers
 the hole.  The middle vessel is furnished
 with a cock e, to draw off its contents.
 The upper  vessel a is fitted, by grinding,
 into the upper neck of the mieldle vessel.
 Its inferior part consists of a tube that passes
 almost  as low as the centre of  the mieldle
 Vessel.   Its  upper orifice  is closed by a
 ground stopper,/*.   When this apparatus is
 to be used,the effervescent materials are put
 into the lower vessel,  the middle vessel is
 filled with  pure water, and put  into  its
 place; and the upper vessel is stopped, and
 likewise put in its place.  The consequence
 is,that the carbonic acid gas,  passing through
 the valve at h, ascends into the upper part of
 the middle vessel b, where,  by its elasticity,
 it reacts on the water, and forces  part up
 the tube into the vessel a ;  part ofthe com-
 mon air, in this last, being compressed, and
 the rest escaping by the stopper, which is
 made of a conical figure, that it may be easi.
 ly raised.  As more carbonic acid is extrica-
 ted, more water rises, till at length the wa-
 ter in the middle vessel falls below the low-
 er orifice ofthe tube.   The gas  then passes
 through the tube into the upper vessel, and
 expels more of the common air by raising
 the stopper.   In this situation the water in
 both vessels being in contact with a body
 of carbonic  acid gas, it becomes strongly
 impregnated with  this gas, after a certain
time. This effect may be hastened by taking
 off the midelle and upper vessels together,
 and agitating them.
   The valve  is the most defective part of
 this apparatus; for the capillary tube does
 not admit the air through, unless there is a
consielerable quantity condensed in the low-
 er vessel; and the condensation has in some
instances burst the vessel.
   Modern discoveries respecting bodies in
the aeriform state have produced several ca-
pital improvements in the vessels used for
distillation.  It was common with the ear-
liest chemists, to make a small  hole in the
upper part of  their retorts, that the elastic
vapours might escape,  which would other-
 wise have burst the vessels. By this meani
 they lost a very considerable part of their
 products.  Sometimes too it is requisite, to
 obtain separately the condensable fluid that
 comes over and  the gases that are and are
 not soluble in water.  For this purpose a se-
 ries of receivers, more or less in number as
 the case may require, is generally employ.
 ed, as in PI. VII. fig.  1. winch represent
 what is called Woult'e s apparatus,  though
 in  fact its original inventor was Glauber,
 with some subsequent improvements.  The
 vapour that issues from the retort being con-
 densed in the receiver a, the gas passes on
 through a bent tube into the bottle c, which
 is half filled with water.   The gas, not ab-
 sorbed by this water, passes through a simi-
 lar bent tube  to  d, and so on to more, if it
 be thought necessary;  while the gas that is
 not absorbable by water, or condensable, at
 its exit from the  last bottle is conveyeel by
 a recurveel tube into a jarjf, standing in a
 mercurial trough//.
   It often happens  in  chemical processes,
 from the irregularity of the heat, or other
 circumstances, that the condensation is more
 rapid in proportion to the supply of vapour
 at some  period ofthe same operation than
 in others ; which would endanger the fluid's
 being forced backward, by the pressure of
 the atmosphere, into the receiver, or even
 into  the retort.  To   prevent this,  Mr,
 Woulfe's bottles had a central neck, beside
 the two here  delineated, for the insertion
 of a tube of safety, the lower extremity of
 which opened underneath the water, and
 the upper communicated with the atmos-
 phere, so as to supply air in case of sudden
 absorption.  See  PI. VII. fig. 3. A.  Instead
 of this, however,  a curveel Welter's tube is
 now generally  used, as more  convenient.
 Into this tube water is poured, till the ball
 b, or e, fig. Lis  half full:  when absorp-
 tion takes place,  the water rises in the ball
 till none remains  in  the  tube, and then the
 air rushes in.- on the  other hand,  no gas
 can escape, as it has to overcome the pres.
 sure of  a high column of water in the per-
 pendicular tube.
  Another contrivance  to prevent retro-
 grade pressure is that of Mr. Pepys.  This
 consists in placing over the first receiver a
 glass vessel, the  neck of which is ground
 into it, and  furnished  with a glass valve,
 similar to that in  Nooth's apparatus, so that
 whenever sudden condensation  takes place
 in the receiver, its effect is merely to occa-
 sion a vacuum there.
  An ingenious  modification of  Woulfe's
 apparatus is that of Mr, Knight,  PI. VI. fig.
 6. a a a represent three vessels each ground
 into the mouth of that below it.  b b b glass
 tubes, the middles of which are ground into
 the neck of their respective vessels, the up-
 per extremity standing above the surt'ace of
the licmor in the vessel,  and the lower ex- 
                LAB

tremity reaching nearly to the bottom ofthe
vessel beneath,  e a \\ elter's tube to pre-
vent absorption. / an adapter ground to
fit the receiver;  to winch any retort may be
joined and  luted before it is put into its
place,  c a tube for conveying the gas into
a pneumatic trough.  I he foot of the lowest
vessel, d, slides in between two grooves in
a square wooden foot, to secure the appa-
ratus irom oversetting.  A  stopple fitted to
the upper vessel, instead of the adapter/,
eonvens it into a booth's  apparatus ;  the
materials being pu.. miotiie vessel a. and in
this case u has the advantage of not having
a valve liable to be out of order.
   A very simple and commodious form  of a
Woulfe's apparatus is given by the late Dr.
W. Hamdton, at uie end of Ins translation of
Berthollet on Dyeing; see PI. Ml. fig. ■>.  a
is the retorc, the neck of which  is ground
into and passed through the thick collar b,
represented separately at b, with its ground
stopple a,  winch may be put in when  the
neck of ttie retort is withdrawn.  The  col-
lar b is ground into  the  wide neck of the
receiver c,  the  narrow  neck of which is
ground into  the wide neck of d. d, e, /,
and,**, are connected in a similar manner;
and into the small necks of d, e, and/, are
ground the tubes i, k, and /, so curved, that
their lower extremities nearly reach the bot-
tom ofthe receiver  into which they open.
From the last receiver proceeds the recurv-
ed tube m, opening  under an inverted cup
n, a hole m the bottom of which  conveys
the gas issuing from it into one of the bottle
placed in the moveable frame p, which has
a heavy leaden foot to keep it steady in the
centre of a flat pan of water, in which the
mouths ofthe bottles are immersed. In the
receiver d is a tube of safety h.   The recei-
vers are placed on a stand a little inclined,
and kept steady by slips of wood hollowed
out to fit their curvatures, as represented at
s s.   This apparatus requires no  lute; has
no bent  tubes  that  are  difficult to adjust,
and liable to break ;  and the retort may be
removed at any stage ofthe process, either
to find the weight it has lost, or for  any
other purpose, the  receiver being mean-
while closed with the stopple.  Similar ad-
vantages attend Mr.  Knight's.
   When it is required to pass an aeriform
fluid through a red-hot substance, such an
apparatus as that of Barruel,  PI. 1. fig. 2.
may be employed.  In this, three gun-bar-
rels, b, c, d, are placed horizontally in a re-
verberatory furnace a, about two inches dis-
tance from' each other.  From the extremi-
tv ofthe central barrel c, a bent tube k con-
veys the gas to the jar m, in the pneumatic
trough /.  The other extremity of c is con-
nected with rfby the curved tube i ; d with
b by the curved tube h;  and the other end
of b with the bottle y  by the tube e.  When
this apparat us is employed for obtaining car-
                LAC

bonic oxide, the part of each barrel exposed
to the fire being filled with charcoal pressed
lightly in, but not rammed hard; carbonate
of lime diluted with a very little water being
poured into the bottle/,- and the junctures
being all well luted, the fire is to be kindled.
As soon as the barrels are red-hot, sulphuric
acid is to be poured into the funnel g,  and
the carbonic acid gas expelled, traversing
three portions of red-hot charcoal, will com-
pletely  saturate itself with it before it
reaches the receiver m.
  Plate V II. fig. 2. represents the different
parts ofthe apparatus required for measuring
the quantity of elastic fluid given out during
the action of an acid on calcareous soils. The
bottle for containing the soil is represented
at a ; b the bottle containing the acid, fur-
nished with a stop-cock; c the tube con-
nected with a rlacciel bladder d,- /a gradu-
ated measure ; e the bottles for containing
the bladder.  \V hen this instrument is used,
a given quantity of soil is introduced into a;
b is filled with muriatic acid, diluted with an
equal quantity of water ;  and the stop-cock,
being closed, is connected with the upper
orifice of a, which is ground to  receive it.
The tube c is introduced into the lower ori-
fice of a, and  the bladder connected with it
placed in its flaccid state in e, which is filled
with water. The graduated measure is plac-
ed under the  tube of e.   When the stop-
cock of b is turned, the acid  flows into a,
and acts upon the soil; the elastic fluid ge-
nerated passes through  c into the bladder,
and displaces a quantity of water in e equal
to it in bulk, and this water flows through
the tube into the graduated measure ; the
water in which gives, by its volume, the in-
dication ofthe proportion of carbonic  acid
disengaged from the soil; for every ounce
measure of which, two grains of carbonate
of lime may be estimated, see Carbonate,
Evdiometeii, and Vapouh.
  Labuadohe Stoxe.  See Feldspar.
  Lac, is a substance well known in  Eu-
rope, under  the different appellations of
stick-lac, shell-lac, and seed-lac.  The  first
is the lac in  its natural state,  encrusting
small branches or twigs.  Seed-lac  is the
stick-lac separated from the twigs, appear-
ing in a granulated form, and probably de-
prived of part of its colouring matter by
boiling.  Shell-lac is the substance which
has undergone a simple purification, as men-
tioned below.  Beside these we sometimes
meet with a fourth, called lump-lac, which
is the seed-lac  melted and  formed  into
cakes.
  Lac is  the product of the coccus lacca,
which deposites its eggs on the branches of a
tree called  Bihar, in Assam, a country  bor-
dering on Thibet, and elsewhere in India.
It appears designed to answer the purpose
of defending the eggs from injury, and af-
fording food for the maggot in a more ad- 
kAC                                 LAK
 «anced state.  It is formed into cells, finish-
 ed with as much  art and regularity  as  a
 honeycomb, but differently arranged; and
 the inhabitants collect it twice a-year, in the
 months of February and August.  For the
 purification, it is broken into small pieces,
 and put into a canvass bag  of about  four
 feet long, and not above six inches in cir-
 cumference. Two of these bags are  in con-
 stant use, and each of them held by two men.
 The bag is placed  over afire, and frequent-
 ly turned, till  the lac is  liquid enough to
 pass through its pores; when it is taken off
 the fire, and twisted in different directions
 by the men who hold it,  at. the same time
 dragging it along the convex part of a plan-
 tain tree prepared for this purpose; and
 while this is doing, the other bag is heating,
 to be treated in the same way.  The muci-
 laginous and smooth surface ofthe plantain
 tree prevents its adhering; and the degree
 of pressure regulates  the thickness of the
 coating of lac, at the same time that the
 fineness of the bag determines its clearness
 and transparency.
  - Analyzed by Mr. Hatchett, stick-lac gave
 in 100 parts, resin 68, colouring extract 10,
 wax 6, gluten 5.5, extraneous substances
 6.5; seed-lac, resin, 88.5, colouring extract
 2.5, wax 4.5, gluten 2; shell-lac, resjn 90.9,
 colouring extract  0.5, wax 4,  gluten 2.8.
 The gluten greatly resembles that of wheat,
 if it be not precisely the same ;  and the wax
 is analogous to that of the myrica cerifera.
  In India, lac is fashioned into rings, beads,
 and other trinkets ; sealing-wax, varnishes,
 and lakes for painters, are made from it;  it
 is much used as a red dye, and wool tinged
 with it, is employed as a fucus by the ladies;
 and the resinous part, melted  and  mixed
 with about thrice its weight of finely pow-
 dered sand, forms  polishing stones.  The
 lapidaries mix powder of  corundum with it
 in a similar manner.
  The colouring matter is soluble in water;
 but 1 part of borax to 5 of lac, renders the
 whole soluble by digestion in water, nearly
 at a boiling heat.  This  solution is equal
 for many purposes to spirit varnish, and is
 an excellent vehicle for  water colours, as
 when once dried, water has no effect on it.
 Lixivium of potash,  soda and carbonate of
 soda, likewise dissolve it. So  does nitric
 acid, if  digested upon it in sufficient quan-
 tity 48 hours.
  The colouring matter of the lac loses
 considerably of its beauty by keeping any
 length of time;  but when extracted fresh,
 and precipitated as alake, it is  less liable to
 injury.  Mr. Stephens, a surgeon in Bengal,
 sent home a great deal prepared in this way,
 which afforded a good scarlet to cloth pre-
viously  yellowed with quercitron; but it
 would probably have been better, if, instead
 of precipitating with alum, he had employ-
ed a solution of tin, or merely evaporated
the decoction to dryness.
  Lac is the basis ofthe best scaling-wai.
  * Lactates.  Definite compounds of lac-
tic acid with the salifiable bases/
  Lacqler.  Solution of lac in alcohol.
  Lake.  This term is usctl to denote a
species of colours formed by precipitating
colouring matter with some earth or oxide.
The principal lakes are, Carmine, Florence-
lake, and lake from Madder.
  For  the  preparation of Carmine,  four
ounces of finely pulverized cochineal are to
be poured into four or six quarts of rain or
distilled water, that has been previously
boiled in a pewter kettle, and  boiled with
it  for  the  space of six minutes  longer;
(some advice  to add, during  the  boiling,
two drachms of pulverized crystals of tar-
tar). Eight scruples of Roman alum in pow-
der are then to be  added,  and the whole
kept upon the fire one minute longer. As
soon as the gross powder has  subsided to
the bottom, and the decoction is become
clear, the latter is to be carefully decanted
into large cylindrical glasses covered over,
and kept undisturbed,  till a fine powder is
observed to have  settled at the bottom.
The superincumbent liquor is then to be
poured off from this powder, and the pow-
der gradually dried.  From the decanted
liquor, which is still much coloured, the rest
of the colouring matter may be separated by
means ofthe solution of tin, when it yields
a carmine little inferior to the other.
  For the preparation  of Florentine lake,
the sediment of cochineal, that remained in
the kettle, may be boiled with the requisite
quantity of water, and the red  liquor like-
wise, that remained after the preparation of
the carmine mixed with it,  and the whole
precipitated with the solution of tin.  The
red precipitate must be frequently edulcor-
ated with water.  Exclusively of this, two
ounces of fresh cochineal, and  one  of crys-
tals of tartar,  are to be boiled  with a suffi-
cient  quantity of water, poured off clear,
and precipitated with  the  solution of tin,
and the precipitate washed.  At the same
time, two pounds of alum are also to be dis-
solved in water, precipitated  with a lixivi-
um of potash, and the white earth repeated-
ly  washed  with boiling water.   Finally,
both precipitates are to be mixed together
in their liquid state, put upon a filter, and
dried.   For the preparation  of a  cheaper
sort, instead of cochineal, one pound of
Brazil wood may be employed in the pre-
ceding manner.
  For  the  following process for making a
lake from madder, the Society of Arts voted
Sir H. C. Englefield their gold medal. En-
close two ounces troy  of the finest Dutch
crop  madder  in  a bag of fine and strong
cahco, large enough to hold three  or four
times as much.  Put it into a large marble
or porcelain mortar, and pour on it a pint
of clear soft water cold.  Press the bag in
tvary direction, and pound and rub  it about 
LAM                                LAM
 with a pestle, as much as can be done with-
 out tearing it, and when the water is load-
 ed with colour, pour it off. Repeat this pro-
 cess till the water comes  off but  slightly
 tinged, for which about five  pints will be
 sufficient.  Heat all the liquor in an earthen
 or silver vessel, till it  is near boiling, and
 then pour it into a large basin, into which a
 troy ounce of  alum dissolved  in a pint of
 boiling soft water has been previously put.
 Stir the  mixture together, and while stir-
 ring, pour in gently about an ounce and a
 half of a saturated solution of subcarbonate
 of potash.  Let it stand till cold to settle ;
 pour off the clear yellow liquor; add to the
 precipitate a quart of boiling soft water,
 stirring it well;  and when cold,  separate by
 filtration the lake, which should weigh half
 an ounce.  If less alum be employed, the
 colour will be somewhat deeper; with less
 than three-fourths of an ounce, the whole
 ofthe colouring matter will not unite with
 the alumina. Fresh madder root is equal, if
 not superior, to the dry.
   Almost all  vegetable colouring matters
 may be precipitated  into lakes, more or
 less beautiful, by means of alum or oxide
 •f tin.
   Lamp.  See Light.
   * Lamp of Safety, for coal mines, the in-
 valuble and splendid  invention of Sir H.
 Davy.  For an account ofthe principles on
 which it acts,  see Combustion.  We shall
 here describe its construction.
   In the parts of coal-mines where danger
 was apprehendedfrom fire-damp,miners had
 been accustomed to guide themselves, or to
 work, by the light afforded by the sparks of
 steel, struck off from a  wheel  of flint.  But
 even this apparatus, though much less dan-
 gerous than a candle, sometimes produced
 explosions ofthe fire-damp.
   A perfect security from accident is, how-
 ever, offered to the miner in the use of a
 safe-lamp, which transmits its light, and is
 fed  with air, through a cylinder of iron or
 copper wire-gauze; and this fine invention
 has the advantage of requiring no machine-
 ry, no philosophical knowledge to direct its
 use, and is made at a very cheap rate.
   The aperturesin the gauze should not be
 more than SV> of an inch  square.  As the
fire-damp is not  inflamed by ignited wire,
the thickness of the wire  is not of impor-
tance,  but  wire from ^y to -£-q of an inch
in diameter is the most convenient.
   The cage,or cylinder should be made by
double joinings, the gauze being folded
over in such a manner, as to leave no aper-
tures. When it is cylindrical, it should not
be more than two inches in diameter; for
in larger cylinders,  the combustion of the
fire-damp renders the  top  inconveniently
hot; and a double top is always a proper
precaution, fixed § or i of an inch above
the first top.
  The gauze cylinder should be fastened ta
the lamp, by a screw of four or  five turns,
and fitted to the screw by a tight ring. All
joinings  in  the lamp should be made with
hard solder; and the security depends upon
the circumstance, that no aperture exists in
the apparatus, larger than in the wire gauze.
  The parts of the lamp are,
  1. The brass  cistern which contains the
oil, pierced near the centre with a vertical
narrow tube, nearly filled with a wire which
is recurved above, on the level of the bur-
ner, to  trim the wick, by acting on the
lower end ofthe wire, with the fingers. It
is called the safety-trimmer.
  2. The rim, in which the wire-gauze cover
is fixed, and which is fastened to  the cistern
by a moveable screw.
  3. An aperture for supplying oil, fitted
with a screw or a cork, and which commu-
nicates with the bottom of the cistern by a
tube ; and a central aperture for the wick.
  4. The wire-gauze cylinder, which should
not have less that  625 apertures to the
square inch.
  5. The second top J of an inch  above
the first, surmounted by a brass or copper
plate, to which the  ring of suspension is
fixed.
  6. Four or six thick vertical wires, joining
the cistern  below, with the top plate,  and
serving as protecting pillars round the cage.
  When the wire-gauze safe-lamp is lighted
and introduced  into an atmosphere gradu-
ally mixed  with  fire-damp,  the first effect
of the fire-damp, is  to increase the length
and size  ofthe flame. When the inflamma-
ble gas forms as much as -j^ of the volume
ofthe air, the cylinder becomes filled with
a feeble blue flame, but the flame ofthe
wick appears burning brightly within the
blue flame, and the light  of the wick aug.
ments till the fire-damp increases to -J- or j,
when it is lost in the flame of the fire-damp,
which in this case fills the cylinder with a
pretty strong fight. As long as any explosive
mixture of gas exists in contact with  the
lamp, so long it will  give  light,  and  when
it is extinguished, which happens when the
foul air constitutes as much as i of the vo-
lume ofthe atmosphere, the air is no longer
proper for respiration; for though animal
life will continue where flame is extinguish-
ed, yet it is always with suffering. By fix-
ing a coil of platinum wire above the wick,
ignition will continue in  the metal when
the lamp itself is extinguished,  and from
the ignited  wire, the wick may be again re-
kindled, on going into a less inflammable
atmosphere.
  " We have frequently used the lamps
where the explosive mixture was so high,
as to heat the wire-gauze red-hot; but on
examining a lamp which has been in con-
stant use  for three months, and occasional-
ly subjected to this degree of heat, I can- 
LAM
LEA
not perceive that the gauze cylinder of iron
wire is at all impaired.  I have not, however,
thought it prudent, in  our present state of
experience, to  persist in using the lamps
under such circumstances,  because I have
observed, that in such situations the parti-
cles of coal dust floating in the air, fire at
the gas burning  within the cylinder, and fly
off in small luminous sparks.  This appear-
ance, I must  confess,  alarmed me in  the
first instance, but experience soon  proved
that it  was not dangerous.
  " Besides the facilities afforded by this
invention, to  the  working of coal-mines,
abounding in fire-damp, it has enabled the
directors and superintendents to ascertain,
with the  utmost precision and expedition,
both the  presence,  the quantity, and  cor-
rect situation ofthe gas. Instead of creep-
ing inch  by inch with a candle, as is usual,
along the galleries of  a mine suspected to
contain fire-damp, in order to ascertain its
presence, we walk firmly on with the safe-
lamps, and,  with the  utmost  confidence,
prove the actual state  ofthe mine.  By ob-
serving attentively the several appearances
upon the flame  ofthe  lamp, in an examina-
tion of this kind,  the cause of accidents
which  happened to the most  experienced
and cautious miners,  is completely devel-
oped ;  and this  has hitherto been in a great
measure matter of mere conjecture.
   " It is not necessary  that I should enlarge
upon the  national advantages which must
necessarily result from an invention, calcu-
lated to prolong our supply of mineral coal,
because I think them  obvious to every re-
flecting mind ;  but 1 cannot conclude, with-
out expressing my highest sentiments of ad-
miration  for those talents,  which have de-
velopeel the properties, and controlled the
power, of one  of the most dangerous ele-
ments, which human enterprize has hither-
to  had to encounter."—See Letter to Sir
H. Davy, in  Journal  of Science, vol.  i. p.
302. by John Ruddle,  Esq. generally and
jus'.ly esteemed the  most scientific  coal-
miner in the kingdom.*
   ♦Lana Pulosophica. The snowy flakes
of white  oxide, which rise and float in the
air, from the combustion of zinc*
   Limpblack.  The finest lampblack is pro-
duced by collecting the smoke from a lamp
with a long wick, which supplies more oil
than can be perfectly  consumed, or by suf-
fering the flame to play against a metalline
cover, which impedes the combustion, not
only by conducting off part ofthe heat, but
by obstructing  the current of air.  Lamp-
black.however, is prepared in a much cheap-
er way, for  the demands  of trade.   The
dregs  which  remain after the eliquation of
pitch,  or else small pieces of fir-wood, are
burned in tiirnaces  of a peculiar construc-
tion, the smoke of which  is made to  pass
tlirough along  horizontal flue, terminating
in a close boarded chamber.  The roof of
this chamber  is  made of  course  cloth,
tlirough which the current of air escapes,
while the soot remains behind.
  Laps Infkhsalis.  Potash.
  Lapis Lazuli.  Azure-stone.
  Lapis Ni.piiiiii-ici's.   See Nephrite.
  Lapis OLi.vHis.   Potstone.
  Lava.  See Yolcaxu Products.
  Lazuli. (Lapis).  Azure-stone.
  Lead, is a white metal of a considerably
blue tinge, very soft and flexible, not ven
tenacious, and  consequently incapable ot
being drawn into fine wire, though it is ea-
sily extended  into thin plates under the
hammer.   Its sp. gr. is 11.35.   It melts at
612°.  In a strong heat it  boils, and emits
fumes; during  which time,  if exposed to
the air, its oxidation  proceeds with con-
siderable rapidity.  Lead is brittle  at the
time of congelation. In this state it may be
broken to pieces with a hammer, and the
crystallization  of  its internal pans will ex-
hibit an arrangement in parallel lines.
  Lead is not much altered by exposure to
air or water, though the brightness of its
surface, when  cut or  scraped, very soon
goes off.  It is probable that a  thin stratum
of oxide isformed on the surface, which de-
fends the rest ofthe metal from corrosion.
  * There are certainly two,  perhaps three
oxides of lead:
  1. The powder precipitateel by  potash
from the solution ofthe nitrate of lead, be-
ing dried, forms  the  yellow  protoxide.
When somewhat vitrified,  it  constitutes
litharge, and combined-with carbonic acid,
white lead or ceruse.  It has been obtained
by  M. Houton-Labillardiere, in dodecahe-
dral white crystals, about the size of a pin-
head, by slow eleposition, from a solution of
litharge in soda.  Heat volatilizes it.  It is
of  very  great  importance to  know accu-
rately the composition of this oxide of lead,
especially in consequence of its great influ-
ence in the analyses of organic bodies. The
mean of Berzelius's last experiments, as de-
tailed in the 5th vol. of the  Afhandlingar i
Fysik, and translated into the Ann. of Phi!.
for February  1820, gives us 7.73 for  the
quantity of oxygen, combined with 100 of
lead in 107.73 of the protoxide; whence the
prime equivalent of lead conies out 12.9366.
The very near approach of this to 13,  will
justify us in aelopting this round number;
and in estimating the equivalent ofthe pro-
toxide  at  14.   The  pigment  massicot  is
 merely this oxide.
   2.  When massicot has been exposed for
 about 48 hours to the flame of a reverbera-
tory furnace, it  becomes red-lead, or mini-
 um.   This substance  has a  sp. gr. of 8.94.
 At a red heat, it gives out oxygen, and pas-
 ses into vitrified protoxide.  It consists of
 100 lead-f- 11.08 oxygen;  and it may be
represented as a compound of 2 prime* Ol" 
LEA                                   LEA
 fcead -f- 3 oxygen; or of 1 prime protoxide
 -f- 1 prime peroxide.
   3. If upon 100 parts  of red-lead, we di-
 gest nitric acid ofthe sp.  gr. 1.26,92.5
 parts will be dissolved, but 7.5 of a dark-
 brown powder will remain insoluble. This
 is the peroxide of lead, and consists of 100
 lead -f 15.4 oxygen; or 13 + 2 = 15.
   By passing a stream of chlorine through
 red-lead diffused in  water, we obtain a so-
 lution, which yields by potash an abundant
 precipitate of the  brown oxide of lead.
 From  100  of minium, 68 of the peroxide
 may be obtained.  It is tasteless, and with
 muriatic acid evolves chlorine.  When heat-
 ed, oxygen is disengaged, and protoxide
 remains.  The red-lead of commerce is often
 very impure,  containing yellow oxide, sul-
 phate of lead, submuriate of lead and silica.
   Chloride of lead is formed, either by plac-
 ing lead in  chlorine, or by exposing the
 muriate to a  moderate heat.  It is a semi-
 transparent grayish-white mass, somewhat
 like horn, whence the old name of plumbum
 corneum.  It is fixed  at  a red heat in close
 vessels, but it evaporates at  that tempera-
 ture in the open air.  By Dr. Davy's analy-
 sis, it consists  of chlorine  25.78 -f- lead
 74.22; or 4.5 + 13.
   The  iodide is easily  formed, by heating
 the two constituents.  It has a fine yellow
 colour.  It  precipitates when we pour hy-
 driodate of potash into a solution of nitrate
 of lead.
   The salts of lead have the protoxide for
 their base, and  are  distinguishable by the
 following general characters:—
   1. The salts which   dissolve  in  water,
 usually give colourless solutions, which have
 an astringent  sweetish taste.
   2. Placed on charcoal they all yield, by
 the blow-pipe, a button of lead.
   3. Ferroprussiate  of potash occasions in
 their solutions a white precipitate.
   4. Hydrosulphuret of potash, a black pre-
 cipitate.
   5. Sulphuretted hydrogen, a black pre-
 cipitate.
   6. Gallic  acid,  and  infusion  of galls, a
 white precipitate.
   7. A plate  of  zinc, a white precipitate,
 or metallic lead.
   Most of the acids attack lead.  The sul-
 phuric does not  act upon  it, unless it be
 concentrated and boiling., Sulphurous acid
 gas escapes during  this process,  and the
 acid is decomposed.  When the distillation
 is carried on to dryness, a saline white mass
remains, a small portion of which is soluble
in water, and is the sulphate of lead; it af-
fords crystals.   The  residue  of the white
mass is an insoluble sulphate of lead.  * It
consists of 5 acid -f-  14 protoxide.*
  Nitric acid acts strongly on lead.
  *The  nitric solution, by  evaporation,
 vields tetrahedral crystals, which arc  white,
   Vor.. IF.
opaque, possess  considerable lustre, and
have a sp. gr. of  4.  They dissolve in 7.6
parts of boiling  water.  They  consist of
6.75 acid -f- 14 protoxide; or nearly 1 -f- 2.
  A subnitrate may be formed in pearl co-
loured  scales, by boiling in water, equal
weights ofthe nitrate and protoxide.
  A subnitrite of lead may be formed, by
boiling a solution of 10 parts ofthe nitrate,
on 7.8 of metallic lead.  If more ofthe me-
tal be used, a quadro-subnitrite results. By
saturating one-half of the oxide ofthe sub-
nitrite,  with  the equivalent proportion of
sulphuric acid, a neutral nitrite is formed.*
  Muriatic acid acts directly on  lead by
heat, oxidizing it and dissolving part of its
oxide.
.  The acetic acid dissolves lead and its ox-
ides; though probably the access of air may
be necessary  to  the  solution ofthe metal
itself in this acid.   White lead, or ceimse, is
made by rolling  leaden plates spirally up,
so as to leave the  space of about  an inch
between each coil, and placing them ver-
tically in earthen  pots, at the  bottom of
which is some good vinegar.  The  pots are
to be covered, and  exposed for a length of
time to a gentle heat in a sand-bath, or by
bedding them in dung.  The vapour of the
vinegar, assisted  by  the  tendency ofthe
lead to combine with the oxygen which is
present, corrodes the lead,  and converts
the external portion into a white substance,
which comes off in flakes, when the lead is
uncoiled.   The plates are thus treated re-
peatedly, until they are corroded through.
Ceruse  is the only white used in oil paint-
ings.  Commonly it is  adulterated with a
mixture of chalk in the shops.   It may be
dissolved without  difficulty  in  the acetic
acid, and affords a crystallizable salt, called
sugar of lead from  its sweet  taste.  This,
like all the preparations of lead, is a deadly
poison.  The common sugar  of lead is an
acetate; and  Goulard's extract, made by
boiling  litharge  in vinegar, a subacetate.
The power of this salt, as a coagulator of
mucus, is superior to the other.  If a bit of
zinc be suspended by brass or iron  wire, or
a thread, in a  mixture of water and the ace-
tate of lead,  the lead will be revived, and
form an arbor Saturni.
  * The acetate, or  sugar of lead, is usually
crystallized in needles, which have a silky
appearance. They are flat four-sided prisms
with dihedral summits. Its sp. gr. is 2.345.
It is  soluble  in three and  a half times its
weight of cold water, and in somewhat less
of boiling water.   Its constituents are 26.96
acid +  58.71  base -f 14.32" water.—Ber-
zelius.
  The subacetate crystallizes in plates, and
is composed of 13.23 acid ■+- 86.77 base; or
1 prime -f-  3.  In the extensive and excel-
lent sugar of  lead works of Mr. Mackintosh,
and of Mr  Ramsay, at Glasgow, this salt if
                 19 
LEV                                  LEV
occasionally formed  in large flat rhomboi-
dal prisms, which  Dr.  Thomson supposes
to consist of five atoms oxide of lead, four
atoms  acetic acid, and 19 atoms water ;
while he considers the ordinary acetate as a
compound  of one  atom aciel, one atom
oxide, and three atoms  water.   The sulphu-
ret, sulphate, carbonate, phosphate, arse-
niate, and chromate of lead, are  found na-
tive, and will be described among its Ores.
  When lead  is alloyed with an  equal
weight of tin, or perhaps even  less, it ceas-
es to be acted on by vinegar.  Acetate and
subacetate of lead in solution, have been
used as external applications  to inflamed
surfaces, and scrofulous sores, and as eye-
washes.  In some extreme cases of h;emor-
rhagy from the lungs and bowels, and uterus,
the former salt has  been prescribed, but
rarely and  in minute doses, asaeorrugant
or astringent.   The colic of the painters,
and that formerly prevalent in certain coun-
ties of England, from the lead  used in the
cyder presses,  show the very  deleterious
operation ofthe oxide, or salts of this metal,
when habitually introduced into the sys-
tem in the minutest  quantities at  a time.
Contraction ofthe  thumbs, paralysis ofthe
hand, or even of the extremities, have not
unfrequently supervened. A course of sul-
phuretted  hydrogen waters,   laxatives, of
which sulphur,  castor-oil, sulphate of mag-
nesia, or calomel,  should  be  preferred, a
mercurial course, the hot sea-bath, and elec-
tricity, are the appropriate remedies.
   Dealers in wines have occasionally sweet-
ened them when acescent, with litharge or
its salts. This deleterious adulteration may
be detected by  sulphuretted  hydrogen
water, which will throw down the  lead in
the state of a dark brown  sulphuret.   Or
subcarbonate of ammonia, which is a more
delicate test, may  be employed to precipi-
tate the lead in the state of a white carbo-
nate ; which, on being washed and digest-
ed with sulphuretted hydrogen water, will
instantly become black.  If the white pre-
cipitate be gently heated,  it  will become
yellow, and, on charcoal before  the blow-
pipe, it will yield a globule of lead. Chro-
mate of potash, will throw down from satur-
nine solutions, a  beautiful orange-yellow
powder.  Burgundy wine, and all  such as
contain tartar, will  not hold lead in solution,
in consequence of the insolubility of the
tartrate.
   The proper  counter-poison for a dange-
rous dose of sugar of lead, is solution of
Epsom or Glauber salt, liberally swallowed;
either  of  which  medicines instantly con-
verts the poisonous acetate of lead into the
inert and innoxious sulphate.  The sulphu-
ret of potash, so much extolled by Navier,
instead of being an antidote, acts itself as a
poison on the stomach.*
  Oils  dissolve the oxide of lead, and be-
come thick and consistent; in which state
they arc  used as  the basis of plasters, ce-
ments for water-works, paints, &c.
  Sulphur readily dissolves lead in the dry
way, and produces a brittle compound, of a
deep gray colour and brilliant appearance-,
which  is  much less fusible than lead itself;
a property which is common to all the com-
binations of sulphur with the more fusible
metals.
  The phosphoric acid, exposed to heat
together with charcoal and lead, becomes
convertedinto phosphorus, which combines
with the metal.  This  combination does
not greatly differ from ordinary lead; it is
malleable,  and easily cut with a knife; but
it loses its brilliancy  more speedily than
pure lead; and when  fused upon charcoal
with the blow-pipe, the phosphorus bunu,
and leaves the lead behind.
  Litharge fused with common salt decom-
poses it; the lead unites with the muriatic
acid, and forms a yellow compound, used as
a pigment. The same decomposition takes
place in the humid way, if common  salt be
macerated  with litharge; and the solution
will  contain caustic alkali.
  Lead  unites with most  of the  metals.
Gold  and  silver  are dissolved by it in a
slight reel heat  Both these metals are said
to be rendered brittle by a small admixture
of lead, though lead itself is rendered more
ductile by a small quantity of them. Pla-
tina forms  a  brittle compound  with lead;
mercury amalgamates with it;  but the lead
is separated from the mercury by agitation,
in the  form of an impalpable black powder,
oxygen being at  the same time absorbed.
Copper  and  lead do not unite but with a
strong heat.  If lead be heated so as to boil
and smoke, it soon dissolves pieces of cop-
per thrown  into it;  the mixture, when
cold, is brittle.   The union of these two
metals is remarkably slight; for, upon ex-
posing the mass to a heat no  greater than
that in which lead melts, the lead almost
entirely runs off by itself.  This process is
called eliquation. The coarser sorts of lead,
which owe their brittleness and granulated
texture to an aelmixture of copper, throw
it up to  the surface on  being melted by a
small heat.  Iron does not unite with lead,
as long as both substances retain their me-
tallic form. Tin unites very easily with this
metal, and forms a  compound, which is
much  more  fusible than lead by itself, and
is, for this  reason, used as a solder for iead.
Two parts of lead and one of tin, form an
alloy more fusible than either metal alone:
this is the solder ofthe plumbers. Bismuth
combines readily  with  lead, and affords a
 metal of a  fine close grain, but very brittle.
 A mixture of eight parts bismuth, five lead,
and three tin, will mdt in a heat which is 
LEV                                   L1G
  not sufficient to cause water to boil. Anti-
  mony  forms a brittle alloy  with lead.
  Nickel, cobalt, manganese, and zinc, do not
  unite with lead by fusion.
    All the oxides of lead are easily revived
  with heat and carbon.
    Leather.  The skins of animals prepared
  by maceration in lime water, and afterward
  with astringent substances.  See Tanking.
    * Leaves of P'.ants. See Chlorophtle.*
    LEts (Soap). See Potasu ;  also Soap.
    Lemons.   See Arm (Citric).
    * Lemma* Eaiith, or Sphrabide.   Co-
  lour yellowish-gray,  and frequently mar-
  bled with rusty spots.  Dull. Fracture fine
  earthy. Meagre to the feel. Adheres slight-
  ly to the tongue. When plunged in water,
  it falls to pieces with disengagement of air-
  bubbles. Its constituents are. 66 silica, 14.5
  alumina, 0.25 magnesia, 0.25 lime, 3.5 soda,
  6 oxide  of iron,  8.5 water.—Klaproth. It
  has hitherto been found only in the Island
  of Stalimene, (ancient Lemnos).  It is rec-
  koned a medicine in Turkey ; and is dug up
  only once a year, with religious solemnities,
  cut into spindle-shaped pieces, anel stamp-
  ed with a seal. It was esteemed an anti-
  dote to poison and the plague in Homer's
  time; a virtue to which it has not the slight-
  est claim.*
    * Lepidolite. Colour peach-blossom red,
 sometimes gray. Massive, and in small con-
 cretions. Lustre glistening, pearly. Cleavage
 single. Fracture, coarse splintery.  Feebly
 translucent.  Soft.  Rather sectile.  Rather
 easily frangible. Sp. gr. 2.6 to 2.8.  It in-
 tumesces before the blow-pipe, and melts
 easily into a milk-white translucent globule.
 Its constituents are 54 silica, 20alumina, 18
 potash, 4 fluate of lime, 3 manganese, and 1
 iron.— Vauquelin.   It occurs in limestone at
 Dalmally, and on the north side of Lochfine;
 on the east side of Loch-leven, nearly  op-
 posite the Inn at Balachulish.  It is found
 in many places  on  the continent.  On  ac-
 count of its beautiful colour, it has been  cut
 into snuff-boxes, but  it is rather soft and
 greasy to the aspect.—Jameson*
   *  Leucite.  Dodecahedral  zeolite   of
 Jameson.  Colour white, whence its name.
 Generally in roundish imbedded grains, or
 crystallized in acute double eight-sided py-
 ramids.  Internal lustre shining.  Cleavage
 imperfect.  Fracture imperfect conchoidal.
 Translucent.  Refracts single. Harder than
 apatite, but softer than feldspar. Brittle. Sp.
 gr. 2.5.  With borax it fuses into a brown-
 ish transparent glass.  Its constituents are
 56 silica, 20 alumina, 20 potash, 2 lime, and
 2 loss —Vauquelin.  It is almost peculiar to
 Italy, occurring  in trap-rocks and lavas, at
 Albano, Frascati, and near Naples.*
   *  Libavius, smoking  liquor of: deuto-
 chloride of tin.*
   Levioation.  The mechanical process of
grinding the parts of bodies to a fine paste,
 by rubbing the flat face of a stone called the
 muller, upon a table or slab called the stone.
 Some fluid is always ad  ed in this process.
 The advantage of levigation with a stone
 and muller, beyond  that of triturating in a
 mortar, is, that the materials can more easi-
 ly be scraped together, and subjected to
 the action of the  muller, than in the other
 case to that of the pestle; and, from the
 flatness of the two suituces, they cannot
 elude the pressure.
    * Lievrite or  Venite.  Colour  black.
 Massive; in distinct concretions; and crys-
 tallized in oblique  or almost  rectangular
 four-sided prisms, varying from acicular to
 the thickness of an inch.  Lateral  planes
 longitudinally streaked.  Lustre glistening,
 semi-metallic. Fracture uneven.  Opaque.
 Scratches glass, and gives a few sparks with
 steel, but is scratched by adularia.  Streak
 unchanged.   Easily frangible.   Sp.gr. 3.9.
 Magnetic on being heated; its colour at the
 same time changing to reddish-brown.  It
 melts into an opaque black bead,  having a
 metallic aspect, and magnetic.  Its constitu-
 ents  are 30 silica. 12.5 lime, 57.5  oxide of
 iron and oxide of manganese, the last of
 which forming only 2 or 3 parts.  It occurs
 in primitive limestone in the island of Elba.*
   * Light.   The agent of vision.
   Some philosophers regard light as con-
 sisting of particles of inconceivable minute-
 ness, emitted in succession by luminous bo-
 dies, which  move in straight lines, at the
 rate of 200,000 miles per second.
   Others conceive that it consists in certain
 undulations communicated by luminous bo-
 dies, to an etherialfluid which fills all space.
 This fluid is  composed of the most subtile
 matter, is highly elastic, and the undulations
 are propagated through it with great velo-
 city, in  spherical superficies proceeding
 from a centre. This view derives great
 plausibility from its happy application by
 Huygens, to explain a very difficult class of
 optical  phenomena,  the  double refraction
 of calcareous spar and other bodies.
   The common refraction is explained by
 Huygens on the supposition, that the undu-
 lations in the luminous fluid are propagated
 in the form of spherical waves.   The double
 refraction is explained on the supposition,
 that the undulations of light, in  passing
 through the calcareous spar, assume a sp/ie-
 roidal form; and this hypothesis, though it
 does not apply with the same simplicity as
 the former, yet admits of such precision, that
 a proportion  of the axes of the  spheroids
 may be assigned, which will account for the
 precise quantity ofthe extraordinary refrac-
 tion, and for all the phenomena dependent
 on it, which Huygenshadstudied with great
 care, and had reduced to the smallest num-
 ber of general facts.
   " That these spheroidal undulations ac-
tually exist," says the celebrated Playfair, 
LIGi                                   Lit;
 " he would after aH be a bold theorist who
 should affirm;  but that the supposition of
 their existence is an accurate expression of
 the phenomena of double refraction, cannot
 be doubted.  When one enunciates the hy-
 pothesis of the spheroidal undulations, he in
 fact expresses  in a single sentence all the
 phenomena of double refraction.   The hy-
 pothesis is therefore the means of represent-
 ing these phenomena, and the laws which
 they obey, to the imagination or the under-
 standing ; and  there is perhaps no theory
 in optics,  and but  very few in  natural phi-
 losophy, of which  more can be said.  The-
 ory therefore, in this instance,  is merely to
 be  regarded as the expression  of a general
 law, and in that light I think it is consider-
 ed  hy La  Place."
  Dr. Young has  selected from Sir Isaac
 Newton's various  writings, many  passages
 favourable to the admission of the undula-
 tory theory of  light,  or of a luminiferous
 ether pervading the universe, rare and elas-
 tic  in a high degree.  " 1$ not  the  heat (of
 the warm room) conveyed through the va-
 cuum by the vibrations of a much subtiler
 medium than air ?  And is not this  medium
 the same with that medium by which light
 is reflected and refracted, and by whose
 vibrations light  communicates heat to bo-
 dies, and is put into fits of easy reflection
 and easy transmission ?  And do not the vi-
 brations of this medium in hot bodies con-
 tribute to  the intenseness and  duration of
 their heat ? And do not hot bodies commu-
 nicate  their heat to contiguous cold ones,
 by the vibrations of this medium, propaga-
 ted from them into the cold ones ?  And is
 not this medium exceedingly more rare and
 subtile than the air, and exceedingly more
 clastic and active ? And doth it not readily
 pervade all bodies ? And is it not by its elas-
 tic  force expanded through all the hea-
 vens ?"—" if any one would ask how a me-
dium can be so rare, let him tell me how an
electric body can by friction emit an exhala-
tion so rare and subtile, and yet so  potent ?
 And how the effluvia of a magnet can pass
through a plate of glass without resistance,
and yet turn a magnetic needle beyond the
 glass ?" - Optics, Qu. 18. 22. " Were I to
 assume an hypothesis, it should be this, if
propounded more generally, so as not to
determine what light is, farther than that it
is something or other capable of exciting
vibrations in the ether ; for thus it will be-
 come so  general, and  comprehensive of
 other hypothesis, as to leave little room for
new ones to be invented."—Birch, iii. 249
  Dr. Young shows, that many  phenomena
 ^explicable on  the notion of radiating cor-
puscles, are easily reconciled to the theory
 of undulation.  « On the whole,"  says this
 profound philosopher, "it appearsthatthe
 few optical phenomena, which  admit of ex-
 planation  by the corpuscular  system,  are
 equally consistent with this theory;  that
 many others which have been long known,
 but  never understood, become by these
 means perfectly intelligible ; and that seve-
 ral new facts are found to be thus, only, re-
 ducible to a perfect analogy with other
 facts, and to the simple principles of the
 undulatory system."—Nat. Pldl. vol. ii. p.
 631.
   I think, however, that the new discoveries
 on polarized light may be  more easily re-
 ferred to the corpuscular  than undulatory
 hypothesis.
   The physical affections of light are foreign
 to this work.  Its  chemical relations are
 alone  to be  considered.   These may be
 conveniently referred to four heads:—
   1. Of the mean refractive and dispersive
 powers of different bodies.
   2. Of the action of the different  prisma-
 tic colours on chemical matter.
   3. Of the polarization of light.
   4. Ofthe absorption and disengagement
 of light, or phosphorescence.
   1. Newton first discovered that  certain
 bodies exercise on light a peculiar attractive
 force.   Wheu a ray passes obliquely from
 air into any transparent liquid or solid sur-
 face, it undergoes at entrance an  angular
 flexure, which is called refraction.   The
 variation of this departure from the rectili-
 neal path for any particular substance, de-
 pends on the obliquity of the ray to the re-
fracting surface; so that the sine ofthe angle
of refraction, is to that of the angle of inci-
dence, in a constant ratio.  Now Newton
found that unctuous or inflammable bodies
occasioned a greater deviation in the lumi-
nous rays than their attractive mass  or den-
sity gave reason to expect.  Hence  he con-
jectured, that both diamond and water con-
tained combustible  matter,— a  sagacious
anticipation of future  chemical discovery.
   Dr. Wollaston invented a very ingenious
apparatus, in which, by means of a rectan.
gular prism of  flint glass, the index of re-
fraction of each substance  is read off at
once by a vernier, the three sides of a move-
able  triangle performing the operations of
reduction, in a very compendious manner.—
Phil. Trans.  1802,  or Nicholson's Journal,
Svo.  vol. iy. p. 89.
  But transparent media occasion not mere-
ly a certain flexure  of the white sunbeam,
called the mean refraction, they likewise de-
compose it into  its  constituent colours.
This effect js called  ttispersion.  Now the
mean refractive and dispersive powers of
bodies are  not proportional to each other.
In some refracting media, the mean angle
of refraction is larger, whilst  the angle of
dispersion is smaller; and in other refract-
ing media, the mean angle of refraction is
smaller, whilst  the  angle of  dispersion is
larger.  In short, the knowledge  of the
mean refractive power of a given substance^ 
LIG                                   L1G
vill not enable us to determine its disper-
sive power, and vice versa.
  From the refractive power of bodies we
may in many cases infertheir chemical con-
stitution.  For discovering the  purity of
essential oils, an examination with Dr. Wol-
laston's instrument may be of considerable
utility, on account of the smallness of the
quantity requisite for trial.  "In oil of
cloves, for instance, I have met with a wide
difference.  The refractive power of genu-
ine oil of cloves is as high as 1.535; but I
have also purchased oil by this name which
did not exceed 1.498, and which had pro-
bably  been adulterated by some less refrac-
tive oil."  This fine idea, suggested by Dr.
Wollaston, has been happily prosecuted by
M. Biot,with regard to gaseous compounds.
I shall first give general tables of the re-
fractive and dispersive powers  of differ-
ent bodies, and  then make  some remarks
on their chemical applications:—
                      Index of Refraction.
A vacuum,                      1.00000
Atmospheric air, (mean,)         1.00033
Ice,                       WoJ.  1.31000
Ice,                   Brewster,  1.30700
Water,         \              1.336
Vitreous humour, 5  Cryolite. B.  1.344
Ether,                     W.  1.358
Albumen,                  W.  1.360
Alcohol,                   W.  1.370
Saturated solut. of salt,    Cavallo,  1.375
Solution of sal ammoniac,         1.382
Nitric acid, sp. gr. 1.48,     W.  1.410
Fluor spar,                 W.  1.433
Sulphuric spar,             W.  1.435
Spermaceti, melted,         W.  1.446
Crystalline lens of an ox,     W.  1.447
Alum,                     W.  1.457
Tallow melted,             W.  1.460
Borax,                      C.  1.467
Oil of lavender,             W.  1.467
                            C. (1.469)
Oil of peppermint,          W.  1.468
Oil of olives,                W.  1.469
Oil of almonds,             W.  1.470
Oil of turpentine, rectified,  W.  1.470
  Do.           common,  W.  1.476
Essence of lemon,           W.  1.476
Butter, cold,                W.  1.480
Linseed oil,                W.  1.485
Camphor,                  W.  1.487
Iceland spar, weakest refr.   Wr.  1.488
  Do.      strongest do.   W. (1.657)
Tallow, cold,               W.  L49
Sulphate of potash,         W.  1.495
Oil of nutmeg,              W.  1.497
French plate-glass,          W.  1.500
English plate-glass          W.  1.504
Oil of amber,               W.  1.505
Balsam of capivi,            "W.  1.507
Gum-arabic,                "W.  1.514
Dutch plate-glass,           W.  1.517
Caoutchouc,                W.  1.524
Nitre,                      *n.  1-524
                     Index of Refraction,
Selenite,                   W.   1.525
Crown glass, common,       W.   1.525
Canada balsam,              W.   1.528
Centre ofthe crystalline of)
  fish, anel dry  crystalline C  W.   1.530
  of an ox,              j
Pitch,                     W.
Radcliffe crown-glass,        W.   1.533
Anime,                    W.   1.535
Copal,                     W.   1.535
Oil of cloves,               W.   1.535
White wax cold,  "^
Elemi,
Mastic,           |
Arseniate of potash, y        W.
Sugar after fusion,  |
Spermaceti cold,   j
Red sealing-wax,  J
Oil of sassafras,              W.   1.536
Bees-wax,                  W.   1.542
Boxwood,                  W.
Colophony,                 W.   1.543
Old plate-glass,              W.   1.545
Rock  crystal, (double),      W.   1.547
Amber,                    W.   1.547
                            C.  (1.556)
Opium,                    W.
Mica,                       W.
Phosphorus,                W.   1.579
Horn,                     W.

Flint-glass,                 AV-£l586
Benzoin,                   W.
Guaiacum,                 W.   1.596
Balsam of Tolu,             W.   1.600
Sulphate of baryt. (double R.) W.   1.646
Iceland spar, (strongest),    W.   1.657
Gum dragon,               W.
Carburet of sulphur,         Br.   1.680
White sapphire,            W.   1.768
Muriate of antimony, variable, W.
Arsenic, (a good test),      W.   1.811
Spindle ruby,              W.   1.812
Jargon,                    W.   1.950
Glass of antimony,           W.  1.980
Native sulphur,             W.  2.040
    Do.             Brewster,  2.115
Plumbago,                 W.
Phosphorus,          Brewster,  2.224
Diamond,    Newton, by Dr. W.   2.440
    Do.                Rochon,  2.755
Realgar,             Brewster,  2.510
Chromate of lead, (least refr.), do.  2.479
    Do.    (greatest refr.)  do.  2.926
TABLE II.—Refracting Powers  of Gases
  for the temperature of 32° F. and pressure
   30, by MM. Biot and Arago.
Atmospheric air,      -      -     1.00000
Oxygen,       -      -      -     0.86161
Azote,   -                      1.03408
Hydrogen,     ...     6.61436
Ammonia,     ...     2.16851
Carbonic acid,  -      -      -     1.00476
Subcarburetted hydrogen,   -     2.09270
Muriatic add gas,     -      -     1.19625. 
LIG                                  LIG
TABLE III.—Dispersive Powers.
Cryolite,	Brewster,		0.023
Fluor spar,		do.	0.022
Water,		do.	0.035
Diamond,		do.	0.038
Flint glass, (highest),		do.	0.052
Carburet of sulphur,		do.	0.115
Phosphorus,		do.	0.128
Sulphur,		do.	0.1.50
Oil of cassia,		do.	0.139
Realgar,		do.	0.255
Chromate of lead, (least	refr	)do.	0.262
Do. (greatest	refr.	) do.	0.400
   Carburet of sulphur exceeds all fluid bo-
 dies in refractive power, surpassing  even
 flint-glass, topaz, and tourmaline;  and in
 dispersive power it exceeds every fluid sub-
 stance, except oil of cassia, holding an inter-
 mediate place between phosphorus and bal-
 sam of Tolu.
   Dr. Brewster has further shown, that all
 doubly refracting crystals have two disper-
 sive powers.
   From Table II. it appears, that the refrac-
 tive power of hydrogen gas greatly surpas-
 ses  not only  that of the other gases, but of
 all known bodies.  This principle exists in
 great abundance, in resins, oils, and gums,
 where it is united to  carbon and oxygen;
 and we must probably ascribe to it, the emi-
 nent refractive power of these combustibles,
 so justly observed by Newton.  This effect
 of hydrogen is finely displayed in ammonia,
 whose refractive power is more than double
 that of air; and much superior to that of
 water.
   But since every substance ought to intro-
 duce into its combinations, its peculiar cha-
 racter, and preserve in them to a certain de-
 gree, the force with which it acts on light,
 let us endeavour to calculate in this point of
 view, the refractive influence ofthe consti-
 tuents of a compound.  From our know-
 ledge ofthe extreme tenuity  of light,  it is
 probable, that the influence of a moderate
 chemical condensation, ought to affect its
 operations very  slightly ; for whether it be
 an ether or a corpuscular emanation, the ex-
 cessive minuteness of its particles, compared
 to the distances between the  molecules of
 bodies,  ought to render the change of dis-
 tance among the latter, unimportant.  Con-
 sequently, the refracting powers of bodies
 ought to differ very little from those of their
 elements, unless a very great degree of con-
 densation has taken place.
   Hence, if we multiply the proportions of
 azote and oxygen respectively, by their re-
fractive powers,  we shall obtain products,
whose sums will coincide with the refractive
power of the atmosphere.  Thus, 100 parts
fay weight ofthe atmosphere, consist of azote
77.77 + oxygen 22.22.  If we multiply
each of these numbers by the number repre-
 senting the refractive power of tbebody, ami
 making a small correc ion for the carbonic
 add present, we shall have for the sum of
 the products 1.0000.
   Ammonia, however, furnishes a more in-
 teresting example ofthe application of these
 principles.
    The refractive power
                  of hydrogen is,  6.61436
                  of azote,       1.0.,4U8
                  of ammonia,    2.16851
   Let x be the weight of the constituent,
 whose refractive power is,             a
 y = 100 — x = that whose power is    b
 and call  the refractive
   power of the compound,             c
            c — b
 Then  x =»-----.  In the  present case,
            a — b
         2.16851 — 1.03408
     x =---------------= 0.203 and
         6.61436—1.03408
 100 — x = 0.797 =  the azote in 100 parts
 of ammonia;  which may be regarded as
 an approximation.   The  true proportions
 given by the equivalentratiosare, 0.823 azote
 -f- 0.177 hydrogen.  If the refractive power
 of ammonia were 2.0218, then the chemical
 and optical analysis would coincide.
   If we calculate on the above data, what
 ought  to be the refractive power of water,
 as a compound of 8 parts of oxygen 4-
 1 hydrogen, we shall obtain the  number
 1.50065, which being multiplied by 0.45302,
 the absolute refractive  power of air,  when
 we take the density of water  for unity, we
 shall have a product =  0.67984.   Now,
 according to Newton's  estimate, which M.
 Biot has found to be exact, the refractive
 power of water is 0.7845.  Hence,  we see,
 that the compound has acquired an  increas-
 ed refractive force by condensation, above
 the mean of its constituents, in the ratio of
 100 to 86|-
   Rays of light, in traversing the  greater
 number of crystallized bodies, are common-
 ly split into two pencils; one of which, called
 the ordinary ray, follows the common laws
 of refraction, agreeably to the preceding
 tables, whilst the other, called the extraor-
 dinary  ray, obeys very different laws.  This
 phenomenon is produced in all transparent
 crystals, whose  primitive form is neither a
 cube nor a regular octohedron. The division
 ofthe beam is greater or less, according to
 the nature of the crystal,  and  the direction
 in which it is cut.  But of all known  sub-
 stances, that which produces this phenome-
 non in the  most energetic manner, is the
 rhomboidal  carbonate of  lime  commonly
 called iceland spar.
   2. Ofthe action of the different coloured
 rays.   If  the white  sunbeam,  admitted
through a small hole of a window-shutter
into  a  darkened  room, be made  to pass
through a triangular prism of  glass, it will 
LIG                                   LIG
be divided into a number of splendid colours
which may be thrown upon a sheet of paper.
Newton ascertained, that if this coloured
image, or spectrum as it is called, be divided
into 36ei parts, the red will occupy 45, the
orange 27, the yellow 48, the green 60, the
blue 60,  the indigo 40,  and the violet 80.
The recLi^yji being least bent by the prism,
froniTtie direction of the white beam, are
said to be least refracted or the least refran-
gible ; while the violet rays being always at
the other extremity ofthe spectrum, are call-
ed the most refrangible.  According to Dr
Wollas.on, when the beam  of light is only
l-20th of an inch broad, and received by the
eye at the distance of 10 feet, through a clear
prism of  flint-glass,  only four colours ap-
pear; red, yellowish-green, blue, and videt.
   If the differently coloured rays of light
thus separated by the prism, be concentred
on one spot by a lens, they will  reproduce
colourless light. Newton ascribes the diffe-
rent colours of bodies, to their power of ab-
sorbing all the primitive colours, except the
peculiar  one  which they  reflect, and of
which colour they therefore appear to our
eye.                            *
   According to Sir  William Herschel, the
different coloured rays possessvery different
powers of illumination. The lightest "green,
or deepest yellow, which are near the cen-
tre, throw more light on a printed page than
any of the rays towards either  side of the
spectrum.  Sir H.  Davy remarks, that as
there are more green rays in a given part of
the sprectrum than blue'rays, the difference
 of illuminating power may depend on this
 circumstance.   The rays separated by one
 prism, are not capable of being further di-
 vided by being passed through another; and
 in their relations to double refraction  and
 reflection, they  appear to agree with direct
 light.  An object illuminated by any of the
 rays in the spectrum, is seen double through
 iceland crystal, in the  same manner as if it
 had been visible by white light.
    Under Calobic, we have stated the pow-
 er of heating which the different coloured
 rays  of the spectrum apparently possess.
 Sir H. Englefield, and M. Berard, confirmed
 the results of Sir W. Herschel, with regard
 to the progressive increase of calorific influ-
 ence from the violet to the red extremity of
 the spectrum ; and they also found with him,
 that  a calorific  influence extended beyond
 the limit ofthe red light, into the unillumi-
 nated space.  M. Berard, however, obser-
 ved, that the maximum of effect was mi the
 light, and  not beyond it.  This ingenious
 philosopher made a pencil of the sunbeam
 pass across a prism of iceland spar. The di-
 vision ofthe rays formed two spectra, which
 presentedthe s'ame properties with the sin-
 gle spectrum.  Both possessed the calorific
 virtue in the same manner and degree.  M.
 Berard polarized a beam of light by reflec-
tion from a mirror; -and he found that in all  i
the positions in which light ceased to be re-  1
fleeted, heat also ceased to appear. | The  '
thermometer in the focus of the apparatus
was no longer affected. Thus, we see, that  ,
the obscure heat-making principle, accom-  .
panies the luminous particles, and obeys the  '
same laws of action.
  If the white luna cornea, the muriate of
silver moistened, be exposed  to the dif-
ferent rays in the prismatic spectrum, it will
be found, that no effect is produced upon it,
in the least refrangible rays, which occasion
heat without light; that only a slight disco-
loration will be occasioned by the red rays;
that the blackening power will be greater
in the violet than in any other ray'; and that
beyond the violet, in a space perfectly ob-
scure to our eyes, the darkening effect will
be manifest on the muriate.
   This fine observation, due to M. Ritter and
Dr. Wollaston, proves, that there are rays
more refrangible than the rays producing
fight and heat.  As it appears, from the ob-
servations of  M. Berthollet, that muriatic
acid gas is formed when horn-silver is black-
ened by light, the above rays may be call-
ed hydrogenating. Sir H. Davy found, that
a mixture of chlorine and hydrogen acted
more rapidly upon each  other, combining
without explosion, when exposed to  the red
rays,  than when placed in the violet rays ;
but that solution of chlorine in  water be-
came solution of muriatic acid most rapidly,
when placed in the most refrangible rays in
the spectrum.  He also observed, that the
puce-coloured oxide of lead, when moisten-
ed, gradually gained a tint of red in the least
refrangible rays, and at last became black,
but was not affected in the most refrangible
 rays.  The same change was produced  hy
 exposing it to a current  of hydrogen gas.
 The oxide of mercury from calomel and wa-
 ter of potash, when exposed to the spectrum,
 was not changed in  the most refrangible
 rays, but became red in the least refrangible,
 which must have been owing to the absorp-
 tion of oxygen.   The violet rays produced
 upon moistened red oxide of mercury, the
 same effect as hydrogen gas.
   Dr. Wollaston found, thatguaiac, exposed
 to the violet rays, passed rapidly from yellow
 to green; and MM. Gay-Lussac and The-
 nard applied to the same influence a gaseous
 mixture of hydrogen and chlorine, when ex-
 plosion immediately took place.  By placing
 small bits of card, coated with moist horn-
 silver, or little phials of those mixed gases,
 in the different parts of the spectrum, M.
 Berard verified the  former observations of
 the chemical power acquiring a maximum
 in the violet ray, and existing even beyond
 it; but he also found, that by leaving  the
 tests a sufficient time in the indigo and blue
  rays, a perceptible effect was produced upon
  them.  He concentrated by a lens all that 
LIG                                  LIG
portion of the spectrum which extends from
the green to the extreme boundary ofthe
violet; and by another lens he collected the
other half of the spectrum, comprehending
the red.  The latter formed the focus of a
white light, so brilliant, that the eye could
not endure it; yet in two hours it produced
no sensible change on muriate of sdver. On
the contrary, the focus of the other half of
the spectrum, whose fight and heat were far
less intense, blackened the muriate in ten
minutes.   The investigations of Ddaroche
enable us, in some measure, to reduce these
dissimilar effects of light to a common prin-
ciple.  See  Caloric
  In Mr Brande's late Bakerian lecture on
the composition and analysis of coal and oil
gases, this ingenious chemist shows, that the
light producetl by these, or by  olefiant gas,
even when concentrated so as to produce a
sensible  degree  of heat,  occasioned no
change on the colour of muriate of silver, nor
onamixture of chlorine and hydrogen; while
the light emitted by electrized charcoal,
speedily  affects the  muriate, causes these
gases to unite  rapidly, anel sometimes with
explosion.   The concentrated  light of the
moon, like that of the gases, proeluced no
change.  He concludes  with  stating, that
he found the photometer of Mr. Leslie in-
effectual. He employed one filled with the
vapour of ether (renewable from a column
of that fluid),  which he found  to be more
delicate.
  The general facts, says Sir H. Davy, of
the refraction  and effects ofthe solar beam,
offer an analogy to the agencies of electrici-
ty.  In the voltaic circuit, the maximum of
heat seems to be at the positive pole, where
the power  of combining with oxygen is
given to bodies, and the agency of render-
ing bodies inflammable is exerted at the op-
posite surface; and similar chemical effects
are produced  by negative  electricity, and
by  the most refrangible  rays  of the solar
beam.  In general, in nature, the  effects
of  the solar rays are  very compounded.
Healthy vegetation  depends upon  the  pre-
sence of the solar beams, or of light; and
whilst the heat gives fluidity and  mobility
to the vegetable juices, chemical  effects
likewise  are occasioned, oxygen is separa-
ted from them, and inflammable compounds
formed.  Plants deprived of light become
white, and contain an excess of saccharine
and aepieous  particles;  and flowers  owe
the variety of their hues to the  influence of
the solar beams.  Even animals require the
presence of the rays ofthe sun, and their
colours seem materially to depend upon the
chemical influence  of these rays; a com-
parison between the polar and  tropical ani-
mals, and between the parts of their bodies
exposed, and  those not exposed  to light,
Shows the correctness of this opinion.
  III. Polarization! of Light.
  This new  branch of  optical  science,
sprung from the ingenuity of Mains.  It has
been since cultivated chiefly by M. Biot in
France, and by Dr. Brewster in this king-
dom.  I  am happy to  observe,  that  Mr.
Herschel has lately entered the lists under
very favourable auspices.
  If a solar ray fall on the anterior surface
of an unsilvered  mirror plate,  making an
angle with it of 35° 25', the ray will be re-
flected in a right line, so that the angle of
reflection will be equal to the angle of inci-
dence.  In any point of its reflected path,
receive it on another plane of similar glass,
it will suffer in general  a second partial re-
flection.   But this reflection will vanish, or
become  null,  if the second plate of glass
form an angle of 35° 25' with the first re-
flected ray, and at the same time be turned,
so that the second reflection is made in a
plane perpendicular to that in which the
first reflection takes place.  For the sake of
illustration, suppose  that the plane of inci-
dence ofthe ray on the first glass, coincides
with the plane ofthe meridian, anel that the
reflected ray  is vertical. Then, if we make
the se»nd inclined plate revolve, it will
turn around the  reflected ray, forming al-
ways with it the same angle; and the plane
in which the second reflection takes place,
will necessarily be directed towards the dif-
ferent points of the horizon, in  different
azimuths. This being arranged, the follow-
ing phenomena will be observed.
   When  the second plane of reflection is
directed in the meridian, and consequentiy
coincides with the first, the intensity ofthe
fight  reflected by the second glass is at its
maximum.
   In proportion as the second plane, in its
revolution, deviates from its parallelism with
the first, the intensity ofthe reflected light
will diminish.
   Finally, when the second plane of reflec-
tion is placed in the prime vertical, that is
east and west, and consequently perpendic*
ular to the first, the intensity ofthe reflec-
tion of light is absolutely null on the two
surfaces  of the second glass, and the ray is
entirely transmitted.
   Preserving the second plate at the same
inclination to the horizon, if we continue
to make  it revolve  beyond  the quadrant
now described, the phenomena will be re-
produced in the inverse order; that is, the
intensity ofthe fight will increase, precise-
ly as it diminished, and it will become equal,
at equal distances from the east and west.
Hence, when the second plane of reflection
returns once  more to the meridian, a second
maximum of intensity equal to the first re-
curs.
   From  these experiments it appears, that
the ray reflected by the first glass, is not re-
flected by the second, under this incidence,
when it is presented to it by its east and west 
LIG                                   LIG
sides; but that it is reflected, at least in part,
when it is presented to the glass by any two
others of its opposite sides.  Now if we re-
gard the ray as an infinitely rapid succession
of a series of luminous particles, the faces of
the ray are  merely the successive faces of
these particles.   We must hence conclude,
that these particles possess faces endowed
with different physical properties, and that
in the present circumstance, the first reflec-
tion has turned towards the same sides of
space, similar faces, or faces equally endowed
at least with the property under considera-
tion. It is this arrangement of its molecules
which Malus named the polarization of light,
assimilating the effect of the first glass to
that of a magnetic bar, which would turn a
series of magnetic needles, all in the same
direction.
  Hitherto  we have supposed that the ray,
whether incident or reflected, formed with
the two mirror plates, an angle of 35° 25';
for  it is only under this angle that the  phe-
nomenon is complete.  Without changing
the inclination of the ray to the first  plate,
if we vary never so little the  inclination of
the second, the intensity ofthe reflected light
is no longer null in any azimuth, but it be-
comes the feeblest possible in the prime ver-
tical, in  which it was formerly nulL
  Similar phenomena may be produced by
substituting for the mirror glasses; polished
plates, formed for the greater part of trans-
parent bodies. The two planes of reflection
must always remain  rectangular,  but they
must be presented to the luminous ray, at
different angles, according to their nature.
Generally,  all  polished surfaces have the
property of thus polarizing, more  or less
completely, the light which they reflect un-
der certain  incidences; but there is for each
of them a particular incidence, in which the
polarization it impresses is most complete,
and for  a great many,  it amounts  to the
whole ofthe reflected light.
  When a ray of light has received polari-
zation in a certain direction, by the processes
now described, it carries with it this property
into space, preserving it without perceptible
alteration, when we make it traverse perpen-
dicularly a considerable mass of air, water,
or any substance possessed of single refrac-
tion.  But the substances which exercise
double refraction, in general alter the polari-
zation of the ray, and apparently in a sud-
den manner, and communicate to it a new
polarization ofthe same nature, but in ano-
ther direction.  It is  only  in  certain direc-
tions ofthe  principal  section, that the ray
can escape  this  disturbing force.  The fol-
lowing may be regarded as the most gene-
ral  view of  this  subject.
  When the particles of light pass through
a crystallized body, endowed with  double
refraction, they experience different move-
ments round their centre of gravity,  which
  Vol. II.
depend on the nature of the forces which the
particles  of  the  crystal  exercise on them.
Sometimes the effect of these forces is limit-
ed to the above polarization, or to the ar-
ranging all the particles of one ray, parallel
to each other, so that their homologous faces
are turned towards the same parts of space.
When this disposition  occurs,  the luminous
molecules preserve it, in the  whole extent
ofthe crystal, and experience no more move-
ment around their centre of gravity.  But
there exists  other cases, in which the mole-
cules that traverse the crystal are not fixed
in any constant position.  During the time
of their passage, they oscillate round their
centre of gravity, with velocities and accord-
ing to periods,  which may be calculated.
Lastly, they sometimes revolve round their
own axes, with an uninterrupted movement
of rotation.  The former is called fixed po-
larization, the latter moveable.
  In the  Phil. Trans, for 1813, we have the
first of a series of very interesting papers on
polarized lightby Dr. Brewster. This relates
chiefly to some curious properties of agate.
The plate of agate which he employed, was
bounded by parallel faces, was about the fif-
teenth of an inch thick,  and was cut  into a
plane, perpendicular to the laminae, of which
it was composed.   When the image  of a
taper reflected from  water at an angle of
52° 45', so as  to acquire the  property dis-
cos ered by Malus, was viewed through the
plate of agate, so as to have its laminae pa-
rallel to the plane of reflection, the flame
appeared perfectly distinct, but when the
agate was turned round, so that its laminae
became perpendicular to the plane of reflec-
tion, the light which  formed the image of
the taper suffered total reflection, and not
one ray of it penetrated the agate.  If a ray
of light incident upon one  plate of agate is
received, after transmission,  upon another
plate of the  same substance, having its lami-
nae parallel to those ofthe former, the light
will find an easy passage through the second
plate; but if the second plate has its laminae
perpendicular to those of the first, the light
will be wholly reflected, and the luminous
object will cease to be visible.
  In a second important communication in
1814 on  the affections of light  transmitted
through crystallized bodies, after suggesting
that the cultivation of this department of phy-
sics may  enable us to explain the forms and
structure of crystallized bodies, a prediction
which he himself has since  happily fulfilled,
the Doctor states, that if the light polarized
by agate, is incident  at a  particular angle
upon any transparent body, so that the plane
of reflection is perpendicular to the laminae
ofthe agate, it will experience a total rejrac-
tion; if it is transmitted  through another
plate of  agate, having its  laminae at right
angles to those of the plate by which the
light is polarized, it will suffer total reflect
                   20 
LIG
LIG
tion;  and if it  is examined  by a prism of
Iceland crystal, turned round in the hand of
the observer, it will vanish and reappear in
every quadrant of its circular motion.  The
pencil of rays to which this remarkable pro-
perty is communicated,  is surrounded by  a
large mass of nebulous light, which extends
about 7° 3u' in length, and 1Q 7'  in breadth
on each side ofthe bright image.   This ne-
bulous light never vanished with the bright
image which it enclosed, but was obviously
affected with its different changes, increasi ng
in magnitude asthe bright image diminished,
and diminishing as the bright image regain-
ed its lustre.  Light polarized by tlie agate,
or by any other means, is  depolarized, or
partly restored to its original state, by being
transmitted in a particular direction through
a plate of mica, or any other crystallized body.
  IV.  Ofthe Production  of Light.
  Some philosophers refer the origin  of all
luminous  phenomena to the  sun, whose
beams are supposed to penetrate, and com-
bine with, the different forms of terrestrial
matter.  But we learn from Scripture, that
light pre-existed  before this luminary, and
that its subsequent condensation in his orb,
was a particular act of Almighty Power.
The phosphorescence of minerals, buried
since the origin of things in the bowels of
the earth, coincides strictly with the Mosaic
account of the creation.  We shall therefore
regard light, the first-born element of Chaos,
as an independent essence,  universally dis-
tributed through the mineral, vegetable, and
animal world, capable of being disengaged
from its latent state by various natural and
artificial operations.   These are
   1. Friction.
  To this head, belong electrical light, and
that evolved from the attrition of pieces of
quartz, even under water.
  2. Condensation and  expansion.   If at-
mospheric air or oxygen be suddenly com-
pressed in a glass syringe, or if a glass ball,
filled with the latter, be suddenly broke in
vacuo, a flash of light is instantly perceived.
  3. Heat.   If air which has been  heated
up to 900° of Fahrenheit, and which  is in
itself obscure,  be made to fall on  pieces
of metal, earth,  &c. it  will speedily com-
municate to them the power  of  radiating
light.  The brilliant flame exhibited in the
burning of charcoal and phosphorus, is shown
in the article Combust on, to be merely the
ignition ofthe solid particles of these bodies.
At a certain elevation of temperature, about
800° Fahr.  all solid bodies begin to  give
out light.  The same  effect is produced in
vacuo  by transmitting  voltaic  electricity
through a metallic wire.  To this section,
we must also refer the phosphorescence of
minerals.  This curious phenomenon seems
to have been first described by Benvenuto
Cellini, in his  Treatise on Jewellery,  pub-
lished near the beginning of the 16th cen-
tury. In the year  1663, Mr. Boyle observed,
that diamond, when slightly heated, rubbed,
or compressed, emitted a light almost equal
to that ofthe glow-worm.
  The most complete account which we
have of mineral phosphorescence, is that re-
cently given by Dr. Brewster in the first vo-
lume of the Edinburgh Phil. Journal.   His
method of examination  was ingenious  and
accurate.  He never reduced  the body to
powder, but placed a fragment of it upon a
thick mass of hot iron, or, in delicate expe-
riments, introduced it into the bottom of a
pistol barrel, heated a little below redness.
The following table presents his results:
Names ofthe Mnerals.	Colour of the Minerals.	Colour and Intensity of the Light.
Fluor spar,	Pink,	Green,
	Purple,	Bluish,
		
	Bluish-white, Yellowish,	Blue, Fine green,
Compact fluor,		
Sandy fluor,	White,	White sparks,
Calcareous spar,	Yellow,	Yellow,
	Transparent,	Yellowish,
		
Limestone from north of Ireland, Phosphate of lime,		Yellowish-red, Yellow,
	Pink,	
Arragonite,	Dirty white,	Reddish-yellow,
Carbonate of barytes,	Whitish,	Pale white,
Harmotome,	Colourless,	Reddish-yellow,
Dipyre,	White,	Specks of light,
Giammatite from Glentilt,	----.	Yellow,
/-. .....ii		Bluish, Bluish,
Topaz, Aberdeenshire,	Blue,	
------■, Brazilian,	Yellow,	Faint vellowiah,
------New Holland,	White,	Bluish,
Rubellitc,	Reddish,	Scarlet,
Sulphate of lime,	Yellowish,	Faint light,
 
LIG                                   LIG
Names ofthe Minerals.    \ Colour ofthe minerals.
Sulphate of barytes,
strontites,

lead,
Ynhydrite,
Sodalite,
Bitter spar,
Red silver ore,
Barystrontianite,
Arseniate of lead,
Sphene,
Tremdite,
Mica,
   — from Waygatz,
Titanium sand,
Hornstone,
Table spar, Dognatska,
Lapis lazuli,
Spodumene,
Titanite,
Cyanite,
Calamine,
Augite,
Petalite,
Abestus, rigid,
Datholite,
Corundum,
Anatase,
Tungstate of lime,
Quartz,
Amethyst,
Obsidian,
Mesotype from Auvergne,
Glassy actinolite,
Ruby silver,
Muriate of silver,
Carbonate of copper,
Green telesie,
Yellow,
Slate colour,
Bluish,

Transparent,
Reddish,
Dark green,
Yellowish,
Ked,
White,
Yellowish,
Yellow,
Whitish,
Greenish,
Black,
Brown,
Black,
Gray,
Whitish,
Blue,
Greenish,
Reddish,
Yellowish-white,
Brown,
Green,
 Reddish tinge,

 Transparent,
 Brown,
 Dark,
 Yellowish-white,
The phosphorescence
of these nine minerals
was observed  in the
pistol barrel.
\C'olour and  Intensity ofthe
          Light.
Pa'e light,
Pale light,
A  fragment  shone pretty
  bright,
Fain: and by fits,
Faint light,
Pretty bright,
Faint white,
Pretty bright, but flitting,
Faint,
Bright white,
Bright white,
 Reddish-j ellow,
 Whitish,
 White specks,
 Pretty bright,
 Feeble specks,
 Yellowish,
 Yellowish,
 Faint,
 Faint,
 Extremely faint,
 Bluish,
 Faint,
 Pretty bright,
 Blue and very bright,
 Pretty bright,
 Bright,
 Bright,
 Reddish-yellow,
   rilt. like a burning coal,
 Very faint,
 Faint,
 Pretty bright; dirty blue,
 Very faint,
 Little specks,
 Rather bright,
 Blue,
 Very faint,
 |Pale  blue, & pretty bright
  The phosphorescence of anatase is entire-
ly different from that ofthe other minerals.
It appears suddenly like a flame, and is soon
over.  Dr. Brewster found,  in opposition to
what Mr. W edgwood had  stated, that  ex-
posure of green fluor spar to the heat of a
common fire in a crucible for  half an hour,
entirely deprived  it  of  phosphorescence.
Though he placed one fragment for several
days in the beams of a summer sun, and even
exposed it to the bright fight near the focus
of a burning glass, he could  not succeed in
obtaining from it the slightest indication of
phosphorescence.   The  light  emitted  in
combustion belongs to the same head.  The
phosphoric light of minerals has the same
properties as the direct light of the sun, ac-
cording to Dr. Brewster.
  4. Light emitted from bodies  in  conse-
quence of the  action of extraneous  light.
To this section  we  refer solar phosphori.
The most powerful of these is the artificial
compound  of Canton.  If we mix  three
parts  of calcined oyster shells  in powder,
with one of flowers of sulphur, and ramming
the mixture into a crucible, ignite it for half
an hour, we shall find, that the bright parts
will, on exposure to the sunbeam, or  to'the
common day light, or to an electrical explo-
sion,  acquire the faculty  of shining  in the
dark,  so as to illuminate "the dial of a watch
and make its figures legible. It will, indeed!
after a while, cease to shine; but if we keep
the powder in a well corked phial,  a new
exposure to the sunbeam will  restore the
luminescence  Oyster shells, stratified with
sulphur, in a crucible, and ignited, yield a
more  powerful  phosphorescent substance
than the powder.  It also must be kept in a
close  phial.  When,  the electric discharge
is transmitted along  the surfaces of certain
bodies,  or a little above them,  a somewhat
durable  phosphorescence  is   occasioned,
which probably belongs to this division. 
LIG                                    LIM
 Sulphate of baryt. gives a bright green light,
 Carbonate            Do. less brilliant,
 Acetate of potash,     Brilliant green light,
 Succinic acid,         Do.   more durable,
 Loaf sugar,           Do.
 Selenite,             Do. but transient,
 Rock-crystal,    Light red, and then white,
 Quartz,               Dull  white light,
 Borax,                Faint green light,
 Boracic acid,          Bright green fight.
   Mr. Skrimshire has given an extensive ca-
 talogue of such substances in Nicholson's
 Journal, 8vo.  vols.  15,  16,  and  19.  He
 shows that Canton's pyrophorus yields more
 light by this treatment than any other body;
 but that almost every native mineral, except
 metallic ores and metals, becomes more or
 less luminous after the electric explosion. A
 slate from Colly Weston, Northamptonshire,
 which effervesced with acids,  gives a beauti-
 ful effect.  When the explosion of a jar is
 taken above the centre of a piece some inches
 square, not only the part above the discharg-
 ing rods is luminous, but the  surface of the
 plate appears bespangled, with very minute
 brilliant points to some  distance  from its
 centre;  and  when the  points of the dis-
 chargers rest upon the surface of the slate,
 these minute spangles are detached and scat-
 tered about the table in a luminous state.
   5. Light emitted during chemical changes,
 independent of heat, or in which no percep-
 tible heat is developed. The substances from
 which such light is emitted, are principally
 the following:—
   Marine animals, both in a living state and
 when deprived of life.  As instances of the
 first may be mentioned, the shell-fish called
 pholas,  the medusa phosphorea, and various
 other mollusca.  When deprived of life, ma -
 rine fishes, in  general, seem to abound with
 this kind of light.  The flesh  of quadrupeds
 also evolves light.   In the class  of insects,
 are many which emit light very copiously,
 particularly several species offulgora, or lan-
 tern-fly ;  and  of lampyris  or glow-worm;
 also the scolopendra electrica,  and a species
 of crab  called cancer fulgens.   Rotten wood
 is well known to evolve  light copiously, as
 well as  peat-earth.
   Dr. Hulme, in an elaborate  dissertation on
 this light,  published in the Phil. Trans, for
 1790,  establishes the following important
 propositions :—
   1. The quantity of light emitted by dead
 animal  substances,  is not in proportion to
■the degree of putrefaction in them, as is
 commonly supposed ;  but, on the contrary,
 the greater the putrescence, the less light is
 evolved.   It would seem, that this  element,
 endowed with pre-eminent elasticity,  is the
 first to  escape from the condensed  state of
 combination in which it had been imprison-
 ed by the  powers of life; and is followed,
 after some lime, by the relatively less elastic
gases,  whose evolution constitutes putre-
faction.
  2. This light  is a constituent  chemical
principle of some bodies, particularly of ma-
rine fishes, from which  it  may be separated
by a peculiar process, retained and rendered
permanent for some time.   A solution of 1
part of sulphate of magnesia, in  8 of water,
is the most convenient menstruum for ex-
tracting, retaining and  increasing  the  bril-
liancy of this light.  Sulphate and muriate
of soda, also answer in a proper state of di-
lution with water.  When any ofthe saline
solutions is too concentrated, the light dis-
appears, but  instantly bursts forth again
from absolute darkness, by dilution with wa-
ter. I have frequently made this curious ex-
periment with the  light procured  from whi-
ting. Common water, lime-water, fermented
liquors, acids even  very dilute, alkaline leys,
and many other bodies, permanently extin-
guish this spontaneous  light.  Boiling water
destroys it, but congelation merely suspends
its exhibition ; for  it reappears on liquefac-
tion.  A gentle heat increases the vividness
of the phenomenon, but lessens its duration.
  We shall conclude the subject of  light
with the following important practical fact
and practical problem.
  1. Count Rumford has shown that the
quantity of light emitted by a given portion
of inflammable matter in combustion, is pro-
portional in some high ratio to the elevation
of temperature; and that,  a lamp, having
many wicks very near each other, so as mu-
tually to increase their heat, burns with in-
finitely more brilliancy than  the  Argand's
lamps in common use.
  2. To measure the proportional intensities
of two or more lights.  Place  them a few
inches asunder, and at the distance of a few
feet or  yards from a screen of white paper,
or a white wall.  On holding a small  card,
near the wall, two shadows will be  projected
on it, the darker one by the interception of
the brighter light,  and  the lighter  shadow
by  the interception of  the duller light.
Bring  the fainter light nearer to the  card,
or remove the brighter one further from it,
till both shadows acquire the same  intensity;
which the eye can judge of with great preci-
sion,  particularly  from  the conterminous
shadows at the angles.  Measure now the
distances ofthe two lights from the wall or
screen, square them, and you have the ratio
of illumination.  Thus if an Argand flame,
and a candle, stand at  the distances of 10
feet and 4 feet, respectively, when their sha-
dows are equally deep,  we have 102  and 42,
or 100 and 16, or 64, and 1, for their rela-
tive quantities of light.*
  * Lilalitk.   The mineral Lepidolite.*
  * Lime.  The oxide  of calcium, one of
the  primitive  earths.   This  subject has
been already treated of under Calcium. We 
                LIM

shall add here, that in preparing the bleach-
ing powder, calcined magnesian  limestone
would be an excellent substitute for common
lime; and it may be  had abundantly from
many districts both of England and Ireland.
Scotland seems to possess little of it.  See
Dolomite.
  The most important applications of lime
are to agriculture and building; on which
subjects Sir H. Davy has given some excel-
lent observations.
  Quicklime  in its pure state, whether in
powder, or dissolved in water, is injurious to
plants.  Grass is killed by watering it with
lime-water.  But lime in its state of combi-
nation with carbonic acid, is a useful ingre-
dient in soils.  Calcareous earth is found in
the ashes  of the  greater number  of plants ;
and exposed to the air, lime cannot long
continue caustic, but soon becomes united
to carbonic acid.
   When  lime,  whether freshly burnt  or
slacked, is mixed with any moist  fibrous
vegetable matter,  there is  a strong action
between the lime and the vegetable matter,
and they form a  kind of compost together,
of which a part is usually soluble in water.
   By this kind  of operation, fime renders
matter, which was before comparatively in-
ert, nutritive ; and as charcoal and oxygen
abound in all vegetable matters, it becomes
at the same time converted into carbonate
of lime.
   Mild lime, powdered hmestone, marls, or
chalks, have no  action of this  kind upon
vegetable matter: by their action they pre-
vent the  too rapid decomposition  of sub-
stances already dissolved; but they have no
tendency to form soluble matters.
   It is obvious  from these circumstances,
 that the operation of quicklime, and marl
or chalk, depends upon principlesaltogether
different.  Quicklime, in the act of becom-
ing mild, prepares soluble  out of insoluble
 matter.
   It is upon this circumstance that the ope-
 ration of lime in the preparation for wheat
 crops depends: and its efficacy in fertilizing
 peats, and in bringing into a state of culti-
 vation all soils  abounding  in hard roots or
 dry fibres, or inert vegetable matter.
   The solution of the question, whetlier
 quicklime ought to be applied to a soil, de-
 pends upon the quantity of inert vegetable
 matter that it contains. The solution ofthe
 question, whether marl, mild lime, or pow-
 dered limestone, ought to  be applied, de-
 pends upon the quantity of calcareous mat-
 ter already in the soil.  All soils are improv-
 ed by mild lime, and ultimately  by quick-
 lime, which do not effervesce  with acids;
 and sands more than clays.
    When a soil,  deficient in calcareous  mat-
 ter, contains much soluble vegetable manure,
 the application of quicklime should always
 be avoided; as  it either tends to decompose
                LIM

the soluble matters by uniting to their car-
bon and oxygen so as to become mild lime,
or it combines with the soluble matters, and
forms compounds having less attraction for
water than the pure vegetable substance.
  The case is the same v> ith respect to most
animal manures; but  the operation ofthe
lime is different in different cases, and de-
pends upon the nature ofthe animal matter.
Lime forms a kind of insoluble soap with
oily matters, and then gradually decomposes
them by separating from them oxygen and
carbon.  It combines likewise with the ani-
mal acids, and probably assist their decom-
position by abstracting carbonaceous matter
from  them  combined with  oxygen; and
consequently it mustreneler them less nutri-
tive.   It tends to diminish likewise the nu-
tritive  powers of albumen from the  same
causes; and always destroys, to a certain
extent, the efficacy  of animal  manures,
either  by combining with certain of their
elements, or by giving to them new arrange-
ments.  Lime should never be applied with
animal manures, unless they are too rich, or
for the purpose of preventing noxious efflu-
via. It is injurious when mixed with any
common dung, and tends to render the ex-
tractive matter insoluble.
   In those cases in which fermentation is
useful  to produce nutriment from vegetable
substances,  lime is always  efficacious, as
with tanners' bark.
   The subject ofthe application ofthe mag-
nesian limestone is one of great interest.
   Magnesia has a much weaker attraction
for carbonic acid than lime, and will remain
in the state of caustic or calcined magnesia
for many  months,  though exposed  to the
air. And as long as any caustic lime remains,
the magnesia cannot be combined with car-
bonic  acid, for lime  instantly attracts car-
 bonic acid from magnesia.
   When a magnesian  limestone is burnt, the
 magnesia is deprived  of carbonic acid much
 sooner than the lime; and  if there is not
 much vegetable or animal matter in the soil
 to supply,  by  its decomposition, carbonic
 acid,  the magnesia will remain for a long
 while in the caustic state; and in this state
 acts as a poison to certain vegetables. And
 that more magnesian lime may be used upon
 rich soils, seems lo be owing to the circum-
 stance, that  the decomposition of the ma-
 nure  in them supplies  carbonic acid.  But
 magnesia in  its mild state,  i. e. fully com-
 bined with carbonic  acid, seems to be  al-
 ways  a useful constituent of soils.
    The Lizard Downs which contain magne-
 sian earth,  bear a short  and green grass,
 which feeds sheep producing excellent mut-
 ton ; and the  cultivated parts are amongst
 the best corn lands in the county of Corn-
 wall.
    It is obvious, from what  has  been said,
 that lime from the magnesian limestone may 
LIM                                  LIM
be applied in large quantities to peats; and
that where lands have been injured by the
application ot too large a quantity of mag-
nesian lime, peat will be a proper and effi-
cient remedy.
  There are two modes in which lime acts
as a cement:  in its combination with water,
and in its combination with carbonic acid.
  When quicklime is rapidly made into a
paste with water, it soon loses its softness,
and the water and the lime form together a
solidcoherent mass, which consists of 1 part
of water to 3  parts of lime.  When hydrate
of lime, whilst it is consolidating, is mixed
with red oxide of iron,  alumina, or silica,
the mixture becomes harder, and more cohe-
rent than when lime alone is used; and it
appears that this is owing to a certain de-
gree of chemical attraction between hydrate
of lime and these bodies; and they render
it less liable to decompose by the action of
the carbonic acid in the air, and less soluble
in water.
  The basis of all cements that are used for
works which  are to be covered with water,
must be formed from hydrate of lime ; and
the lime made from impure  limestones an-
swers this purpose very well. Puzzolana is
composed principally of silica, alumina, and
oxide of iron; and it used mixed with lime
to form  cements intended to be employed
under water.  Mr. Smeaton, in the construc-
tion ofthe Eddystone light-house, used a
cement  composed of equal parts by weight
of slacked lime and puzzolana.  Puzzolana
is a decomposed lava.  Tarras, which was
formerly imported in considerable quanti-
ties from Holland, is a mere decomposed
basalt:  two parts of slacked lime anel one
part of tarras  form the principal part ofthe
mortar used in the great dykes of Holland.
Substances which  will answer all the ends
of puzzolana and tarras are abundant in the
British  islands.  An excellent  red tarras
may be procured in any quantities from the
Giants'  Causeway, in the north of Ireland;
and elecomposing basalt is abundant in many
parts  of Scotland, and in the northern dis-
tricts  of England in which coal is found.
  Parker's cement, and cements ofthe same
kind maele at the alum works of Lord Dun-
das and Lord Mulgrave, are mixtures of cal-
cined ferruginous, silicious, and  aluminous
matter, with hydrate of lime.
  The  cements which  act  by combining
with carbonic acid, or the common mortars,
are made by mixing together slacked lime
and sand. These mortars, at first solidify as
hyelrates,  and are  slowly converted into
rarbonate of  lime by the action of the car-
bonic acid of the air.  Mr. Tennant found
that a mortar of this kind,  in three years
anel a quarter, had regained  63 per cent of
the quantity  of carbonic acid  gas, which
constitutes the definite  proportion in car-
bonate of lime. The rubbish of mortar from
houses owes its power to benefit lands prin-
cipally to the carbonate of lime it contains,
and the  sand in it;  and its state of cohesion
renders it  particularly  fitted to improve
clayey soils.
  The hardness  of the mortar in very old
buildings depends upon the perfect conver-
sion of all its  parts into carbonate of lime.
The purest limestones are the best aelaptcd
for making this kind of mortar; the magne-
sian  limestones  make excellent  water ce-
ments, butact with too little energy upon car-
bonic acid gas to make good common mortar.
  The  Romans,  according  to Pliny, made
their best mortar a year  before it  was used;
so that it was partially combined with car-
bonic acid gas before it was employed.
  In burning lime there are some  particular
precautions required for the different kinds
of limestones.   In general, one  bushel of
coal is sufficient  to make four or five bush-
els of lime.  The magnesian  limestone re-
quires less fuel than the common limestone.
In all cases in which  a limestone containing
much aluminous  or siliceous earth is burnt,
great care should be taken to prevent the
fire from becoming  too intense ; for such
lime easily  vitrifies, in consequence of the
affinity  of lime for  silica  and alumina  And
as in some places there are no other lime-
stones than such as contain other earths, it
is important to attend to this circumstance.
A moderately good lime may be  made at a
low red heat; but it will melt into a glass at
a white  heat.  In  limekilns for burning such
lime, there  should be always a damper.
  In general,  when limestones are not mag-
nesian,their purity  will be indicated by their
loss of weight in burning; the more they
lose, the larger is the quantity of calcareous
matterthey contain.  The magnesian lime-
stones contain more  carbonic  acid than the
common limestones;  and all  of  them lose
more than half their weight by calcination.
   The most important compounds of lime,
are treated of under  the different acids and
combustibles.*
  * Li iifstone.  A genus of minerals, which
Professor Jameson divides into the four fol-
lowing  species: 1.  Rhomb-spar; 2.  Dolo-
mite ; 3. Limestone; and, 4. Arragonite.
We shall consider the  third  species here.
The  same excellent mineralogist divides
limestone' into twelve sub-species.
  1. Foliated limestone; of which there are
two kinds,  calcareous spar, and foliated gra-
nular limestone.   The first will be found in
its alphabetical place in  the Dictionary.
  Granularfoliated limestone. Colour white,
of various shades;  sometimes it is spotted.
Massive, and indistinct angulo-granular con-
cretions. Lustre glistening, between pearly
and vitreous.  Fracture  foliated.   Translu-
cent. Hard as calcareous spar. Brittle. Sp.
gr. Carrara marble 2.717. It generally phos-
phoresces when  pounded, or when thrown 
LIM
LIM
on glowing coals.  Infusible.  Effervesces
with acids.  It is a pure carbonate of lime.
It occurs in beds in granite, gneiss, &c. and
rarely in secondary rocks.  It is found in all
thegreatrangesof, rimitiverocksinEurope.
Parian marble, Penteiic marble, the Marmo
Greco, the white marble of Luni, of Carrara,
and  of  Mount  Hyme-.tus, the translucent
white marble of statuaries, and flexible white
marble,  are the chief of the  white marbles
which tne ancients wsed for sculpture and
architecture. The red antique marble, Rosso
antico of the Italians, and Egyptian  of the
ancients;  the  Verde antico, an indetermi
nate mixture of white marble and green ser-
pentine ; yellow  antique marble;  the an-
tique Cipohn maible, marked with green-co-
loured zones, caused by talc  or  chlorite ;
and  African breccia marble, are the princi-
pal coloured marbles ofthe ancients.   The
Scottish marbles are, the red anel white Ti-
ree, the former  of  which  contains horn-
blende, sahlite, mica, and green earth ;  the
Iona marble, harder than most others, con-
sisting of limestone and tremolite, or occa-
sionally a dolomite; the Skye  marble;  the
Assynt in Sutherland, introduced into com-
merce by  Mr.  Joplin of Gateshead.  It is
white  and gray, of various shades.  The
Glentilt marble ; the  Balachulish ;  the
Boyne;  the  Blairgowrie; and the  Glena-
von.  Hitherto but few marbles of granular
foliated  limestone have been quarried in
England.  The Mona marble is not unlike
 Verde antico. The black marbles of Ireland,
now so generally used by  architects, are
Lucullites.   The Toreen, in the county of
Waterford, is a fine variegated sort; and a
gray marble beautifully clouded with white,
has been found near Kilcrump, in the same
county.  At Loughlougher in Tipperary, a
fine purple marble is found.  The county
of Kerry affords several variegated marbles.
Of the continental marbles a good account
is given by Professor Jameson, Mineralogy,
vol. ii. p. 502.
   2d Sub-species.  Compact limestone; of
which there are three kinds, common com-
pact limestone,  blue  Vesuvian limestone,
and roestone.
   Common compact limestone has usually
a gray colour, with coloured delineations.
Massive, corroded, and in various extrane-
ous shapes.  Dull.  Fracture fine splintery.
Translucent on the edges.   Softer than the
preceding sub-species.   Easily  frangible.
 Streak  grayish-white.  Sp. gr.  2.6 to 2.7.
It effervesces with  acids,  and  burns  into
quicklime.   It is a carbonate  of  lime, with
variable and generally  minute proportions
 of silica, alumina, iron, magnesia, and man-
 ganese.  It occurs principally in secondary
 formations, along with  sandstone, gypsum,
 and coal.   Many animal  petrifactions, and
 some vegetable, are found in it. It is rich
 in ores of lead and zinc; the English mines
ofthe former metal being situated in lime-
stone.  When it is so hard as to take a po-
lish, it is worked as a marble, under the
name of shell,  or lumaccel.a  marble.   It
abounds in the  sandstone and  coal forma-
tions, both in Scotland and England; and
in Ireland it is a very abundant mineral  in
all the districts, where clay-slate and  red-
sandstone occur.  The Florentine marble,
or  nun marble, is  a  compact limestone.
Seen at a distance, slabs of this stone resem-
ble, drawings done in bistre.
  2.  Blue  Vesuvian limestone.   Colour
dark bluish-gray,  partly veined with  white.
Rolled and uneven  on the surface.   Frac-
ture tine earthy.  Opaque.  Streak white.
Semi-hard in a low degree.   Feels  heavy.
Its constituents are, lime 58, carbonic acid
^8.5, water somewhat ammoniacal 11, mag-
nesia 0.5, oxide of  iron 0.25,  carbon 0.25,
and sdica 1.25.—Kiaproth.  it is  found in
loose masses among unaltered  ejected mi-
nerals, in  the neighbourhood  of Vesuvius.
In mosaic work, it is use (Wo r representing
the sky.
   3. Roestone.  Colours brown  and gray.
Massive, and in distinct concretions, which
are round granular.  Dull.  Opaque.  Frac-
ture of the mass round granular. Approach-
ing to soft.  Brittle.  Sp. gr. 2.6 to  2.68.
It dissolves with effervescence in acids.  It
occurs along  with  red-sandstone and Has
limestone,  in  England this rock is called
Bath-stone, Ketton-stone, Portland-stone,
and Oolite.  It extends, with  but little in-
terruption, from Somersetshire to the banks
of the Humber in Lincolnshire.   It is used
in architecture, but it is porous, and apt to
moulder away, as is seen in the ornamental
 work ofthe Chapel of Henry VIII.
   3d Sub-species.  Chalk, which see.
   4th. Agaric  mineral, or rock-milk.  Co-
 lour white.  In crusts or tuberose  pieces.
 Dull.  Composed  of fine dusty  particles.
 Soils  strongly.  Feels  meagre.  Adheres
 slightly to the tongue. Light, almost super-
 natant.  It dissolves in  muriatic acid with
 effervescence, being a pure  carbonate of
 lime.  It is found on the north side of Ox-
 ford, between  the  Isis and the Cherwell,
 and  near Chipping Norton;  as also in  the
 fissures of limestone caves on the Conti-
 nent.  It is formed by the attriction of wa-
 ter on limestone  rocks.
    5th Sub-species.   Fibrous limestone; of
 which there are two kinds, satin-spar, or the
 common fibrous;  and fibrous calc-sinter.
 Satin-spar. White of various  shades.  Mas-
 sive,  and in  distinct fibrous concretions.
 Lustre glistening  and pearly ; fragments
 splintery; feebly translucent;  as hard as cal-
 careous spar;  easily frangible;  sp. gr.  2.7.
 Its constituents are, lime 50.8, carbonic
 acid 47.6 ?  Stromeyer says it contains some
 per cents of gypsum.  It occurs in thin lay.
 ers in clay-slate  at Aldstone-moor in CuraJ 
LIM                                    LIM
berland; in layers and veins in the  middle
district of Scotland, as in Fifeshire.  It is
sometimes cut into necklaces,  &c.
  Fibrous culc-sinter  It is used as marble,
and the  ancients formed it into unguent-
vases, the atabuster~box of Scripture.  See
CaLC-SiNTKU.
  6th Sub-species.  Tufaceous limestone,
or Calc-tuff'.  Colour gray.  Massive, and
in imitathe shapes, enclosing leaves, bones,
shells,  &.c.  Dull.  Fracture fine  grained
uneven.   Opaque.  Soft.  Feels  rough.
Brittle.   It is pure carbonate of lime. It oc-
curs in beds, generally in the neighbourhood
of rivers ; near Starly-burn in Fifeshire, and
other places.  Used for lime.
  7th Sub-species.  Pisiform limestone, or
Peastone.  Colour yellowish-white.  Mas-
sive, and in distinct concretions, which are
round granular, composed of others which
are very thin and concentric lamellar.  In
the centre there  is a bubble of air, a grain
of sand, or of some mineral matter.  Dull.
Fracture  even. 4- Opaque.  Soft.   Brittle.
Sp. gr. 2.532.  It is carbonate of lime.  It
is found  in  great masses in the vicinity of
Carlsbad in Bohemia.
  8th Sub-species.  Slate-spar.  Schiefers-
path.  Colour  white,  of various  shades.
Massive,  and  in  distinct curved  lamellar
concretions.  Lustre glistening anel pearly.
Feebly translucent.  Soft; between sectile
anel brittle.   Feels rather greasy.   Sp. gr.
2.63. Its constituents are carbonate of lime,
with three per cent of oxide of manganese.
It occurs in primitive limestone, in  metalli-
ferous beds and in veins. It is found in
Glentilt;  in Assy nt; in Cornwall; and near
Granard in Ireland.
  9th Sub-species.  Aphrite,  which see.
   10th  Sub-species.  Luculhte ; of which
there are three  kinds, compact, prismatic,
and fo.iated.
   § 1. Compact is subdivided  into the com-
mon or black marble ; and the stinkstone.
   a. The common compact. Colour grayish-
black.   Massive.  Glimmering.  Fracture
fine  grained uneven.   Opaque.   Semi-
harel.  Streak, dark ash-gray.  Brittle.  Sp.
 gr. 3.   When  two  pieces are rubbed to-
gether, a fetid urinous  odour is  exhaled,
which is increased by breathing on them.
 It burns white, but forms a black-coloured
 mass with sulphuric acid.  Us constituents
 are, lime 53.08, carbonic acid 41.5, carbon
 0.75, magnesia  and oxide of manganese
 0.12, oxide of iron 0.25.  silica 1.13, sulphur
 0.25, muriates and sulphates of potash with
 water 2.62.—John.  It is said to  occur  in
 beds in primitive anel older secondary rocks.
 Hills of this mineral occur in the district of
 Assynt  in  Sutherland.   Varieties of it are
 met with in Derbyshire;  a.l killenny ;  in the
 counties of Cork and oalway. The consul
 Lucullus admir_,', it so  much, as to give it
 his name.   It is the Nero  antico of the
 Italians.
  b. Stinkstone, or  Siumestmir.   Colour
white, of many  shades, cream-yellow, gray,
black, and brown,  Massive, disseminated,
and in distinct granular concretions.  Dull.
Fracture splintery.  Opaque.   Semi-hard.
Streak grayish-white.  Emits a fetid odour
on  friction.  Brittle.  Sp. gr.  2.7.   The
same chemical characters as the preceding.
Its  constituents are,  88  carbonate  of lime,
4.13 silica, 3.1 alumina. 1.47 oxide of iron,
0.58 oxide of manganese, 0.30 carbon, 0.58
lime; sulphur,  alkali,  salt, water, 2.20.—
John.   It occurs in beds in secondary lime-
stone, alternating occasionally  with secon-
dary gypsum and beds of clay.   It is found
in the vicinity of North Berwick, resting on
red sandstone, and in the parish of Kirbean
in Galloway. It  is  employed for  bunting
into lime.
  § 2. Prismatic luculhte.  Colours black,
gray, and brown.  Massive, in balls, and in
distinct concretions.  External surface some-
times  streaked.  Internal  lustre  shining.
Cleavage threefold.  Translucent on the
edges.  Semi-hard.  Streak gray-coloured.
Brittle.  When rubbed it emits a  strongly
fetid urinous smell.  Sp. gr.  2.67. When
its powder is boiled in water, it gives out a
transient hepatic  odour.  The water be-
comes slightly  alkaline.  It dissolves with
effervescence in  muriatic acid, leaving a
charcoaly residuum. Its constituents re-
semble those of the  preceding.  It occurs
in balls, in brown  dolomite,  at Building-
hill, near Sunderland.  It was at one time
called madreporite.
  § 3. Foliated or sparry luculhte. Colours
white, gray, and black.  Massive,  dissemi-
nated and crystallized in acute six-sided py-
ramids.  Internal lustre glimmering.  Frag-
ments rhomboidal.  Translucent.  Semi-
hard.  Brittle.   Emits on friction a urinous
smell.  Sp. gr. 2.65.   In other  respects
similar to  the  preceding.  It  is  found  in
veins at Andreasberg, in the Hartz.
  11th Sub-species.  Marl; of which there
are two kinds,  earthy and compact. Earthy
marl has a gray colour, consistsof fine dusty
particles, feebly cohering; dull; soils slight-
ly ;  is light; effervesces with acids;  and
emits  a  urinous smell  when first dug up.
Its  constituents are carbonate of lime, with a
little alumina, silica, and bitumen.  It oc-
curs in beds in the secondary limestone and
gypsum formations in Thuringia and Mans-
t'eld.   Compact marl has a gray colour; is
massive, vesicular, or in flattened balls; con-
tains petrifactions;  dull;  fracture earthy,
but in the great  slaty; yields  to  the  nail;
opaque; streak grayish-white ;  brittle ; feels
meagre; sp.gr. 2.4.  It intumesces before
 the blow-pipe, and  melts into a  greenish-
 black slag.  It effervesces with acids.   Its
 constituents are carbonate of lime 50, silica
 12, alumina 32, iron and oxide of manga-
 nese 2.—Kirwun.  It occurs in bcels in the
 secondary  floetz limestone.   It is frequent 
                 LIT

in the coal formations of Scotland and Eng-
lanel.
  12th Sub-species. Bituminous  marl-slate.
Colour  grayish-black.  Massive, and  fre-
quently with impressions oi'fishes and plants.
Lustre glistening. Fracture slaty. Opaque.
Shining streak.  Soft.  Sectile.  Frangible.
Sp. gr. 2 66. Uis said to be carbonate of lime,
with albumen, iron, and bitumen. It occurs
in floetz limestone.  It frequently  contains
cupreous minerals, petrified fishes, and fossil
remains of cryptogamous plants. It abounds
in the Hartzgebirge.—Jameson.*
  Liquefaction*. A chemical term, in some
instances synonymous with the word fusion,
in others  with the  word deliquescence, and
in others again with the word solution.
   * LiauiniTT.  See Caloric*
   Liquor of Flints.   See Silica.
   * Lithia.   A  new alkali.  It was disco-
 vered by M. Arfwedson, a  young chemist of
 great merit, employed in the laboratory of
 M.  Berzelius.  It  was  found in a mineral
 from the mine of  Uten, in Sweden, called
 petalite, by M. d'Andrada, who first distin-
 guished it.  Sir II. Davy demonstrated  by
 voltaic electricity, that the basis of this alka-
 li is a metal, to  which the name of lithium
 has been given.
   Berzelius gives the following simple pro-
  cess as a test for lithia in minerals:—
   A fragment ofthe mineral, the size of a
  pin's head, is to be heated with a small ex-
  cess of soda, on a piece of platinum foil, by
  a blow-pipe for a couple of minutes.  The
  stone is decomposed, the  soda liberates the
  lithia, and the excess of alkali preserving
  the whole  fluid  at  this  temperature,  it
  spreads over the foil, and surrounds the de-
  composed mineral.  That part of  the plati-
  num near to the fused alkali becomes of a
  dark colour,  which is more intense,  anel
  spreads over a larger surface, in proportion
  as there is more lithia in the mineral.  The
  oxidation ofthe platinum does not take place
  beneath the alkali, but only around it, where
  the metal is in contact with both airand lithia.
  Potash destroys the reaction ofthe platinum
  on the lithia, if the lithia  be not redundant.
  The platinum resumes its metallic surface,
  after having  been washed and heated.
     Lithia may be obtained by fusing petalite
  with potash, dissolvingthe whole in muriatic
  acid, evaporating to dryness, and digesting
  in alcohol.  The muriate  of  liihia,  being
  very soluble in that fluid, is taken up, while
  the'other salts remain.   By a second  eva-
   poration and solution in alcohol, it is  obtain-
   ed perfectly  pure. The muriate isitselfasalt
   very characteristic of  the alkali.   It may
   easily be decomposed by carbonate of silver;
   anel  the carbonate thus  procured, when
   treated with lime, yields  pure  lithia.   Dr.
   Gmelin fused  petalite with five  times  its
   weight of nitrate of barytes, at a white heat,
   in a platinum crucible;  digested the.  mass
      Vox. II.
                 LIT

in muriatic acid ; evaporated the solution to
dryness; dissolved in water; separated the
silica ; and added rather more sulphuric acid
than was equivalent to the barytes.  The
sulphate of barytes was got rid of by solution
in water and filtration.  The liquid was now
concentrated by evaporation to e\pel the ex-
cess of muriatic acid.  It was then supersa-
turated with carbonate of ammonia, which
threw down the  alumina  and  the oxide of
iron. The filtered liquid was evaporated to
dryness, and the residue was ignited, to drive
off' the ammoniacal sulphate  and muriate.
The remainder was dissolved in water, and
hydrosulphuret of ammonia  was added to
the solution to separate the manganese. Be-
 ing now filtered, evaporated, and ignited, it
 was pure sulphate of lithia, from which he
 obtained the carbonate by adding acetate of
 barytes, and decomposing the resulting ace-
 tate of lithia by a red heat.
   The first is the process of M. Vauquelin,
 and is vastly the simpler of the two.  The
 most complete account, however, which we
 have of lithia audits compounds, is that of
 Dr. Gmelin.  He had the benefit indeed of
 M. Vauquelin's  very able researches,  pub-
 lished in the  Ann. de Chimie et  Phys. vii.
  287.   Dr.  Gmelin's memoir  is inserted in
  the 62d volume  of Gilbert's Annalen.
    Caustic  liihia has a very sharp burning
  taste.  It destroys the cuticle  of the tongue,
  like potash.  It does not dissolve with great
  facility in water, and appears not to be much
  more soluble in hot than in cold water. In
  this respect it  has an analogy  with lime.
  Heat is evolved during its solution in water.
    When exposed to the air, it does not at-
  tract moisture,  but  absorbs  carbonic  acid,
  and becomes opaque.  When exposed for
  an hour to a white heat in a covered plati-
  num crucible, its bulk does not appear to be
  diminished; but it has absorbed a quantity
  of carbonic acid.
     It dissolves only  in small quantity in al-
  cohol of the specific gravity 0.85.  When
  weak alcohol is added to an aqueous solution
  of lithia in a well stopped phial, no change
  takes place at first; but after some hours
  the lithia precipitates in the state of a white
  poweler.
     Lithia unites with sulphur, according to
  Vauquelin.  Sulphuret of lithia has a yellow
   colour, dissolves readily in water, and is de-
   composed by acids in the same way as the
   other alkaline sulphurets.
     Phosphorus decomposes  water with the
   help of caustic lithia.  If we heat in a retort
   phosphorus with a solution of caustic lithia
   in water, phosphuretted hydrogen gas is
   disengaged, which catches fire when  it
   comes into the air.
     Neutral sulphate of lithia forms small pris-
   matic crystals, having a go*l deal of lustre,
   sometimes  constituting pretty long, but nar-
    row tables.  When exposed to the air, they
                     21 
LIT
LIT
 undergo only an insignificant efflorescence.
 This salt  has  a saline and  scarcely bitter
 taste.  It dissolves pretty readily in  water,
 and  melts when exposed to a temperature
 scarcely reaching a red heat.
   Bisulpliate of lithia dissolves in water with
 greater facility  than the neutral sak.   It
 forms six-sided tables, in which two  of the
 faces, which are parallel to each other,  tar
 exceed the remaining ones in length.  When
 exposed to a very high temperature, it gives
 out sulphurous acid and oxygen gas,  and is
 Converted into the neutral sulphate
   According to Arfwedson, this bisalt dis-
 solves with more difficulty in water than the
 neutral salt.
   Phosphate  of lithia.—Phosphoric  acid,
 when dropped into the solution of sulphate
 of lithia, occasions no precipitate. But when
 the uncombined acid is saturated by ammo-
 nia, the phosphate of lithia is precipitated in
 the state of white flocks, which are insoluble
 in water.
   When a drop of phosphoric acid islet fall
 into a very dilute solution of carbonae of
 lithia, no precipitate falls ; but when  the li-
 quid is  heated, the carbonic  acid gas  is dis-
 engageel, and phosphate of lithia falls  down.
 From this it would seem,  that the solubility
 of phosphate of lithia in water is owing to
 the presence of the carbonic acid.
   There exists likewise mbiphosphate of lithia.
 It is obtained by dissolving the neutral salt
 in phosphoric acid.  By a very slow evapo-
 ration of this solution, we obtain transparent
 granular crystals.
  Nitrate of lithia forms four-sided prisms
 with rhomboidal bases.  It has a very pun-
 gent taste, and seems to surpass  almost  all
 other salts in deliejuescency.   In a very hot
day,  it  crystallized  in  the  sun ;  but deli-
 quesced again in the shade.  It dissolves m
 the strongest alcohol.
  Carbonate  of Jithia constitutes a  white
powder.. It dissolves with great difficulty in
cold water.  According to Vauquelin, 100
parts  of water dissolve scarcely one part  of
this salt.   It is more  soluble,in hot water.
A solution of carbonate of lithia containing
only l-1000th  of its weight of the salt, acts
 strongly as an alkali.
  0.535 grammes of fused carbonate of lithia
were, by means of sulphuric acid and ex-
posure to a strong heat, converted into 0 765
 of neutral  sulphate  of lithia.  Now this
quantity of sulphate contains 0.2436 of lithia.
  Hence 0.535  of carbonate of  lithia are
 composed of
         Lithia,               0.2436
         Carbonic acid,        0.2914
                              0.5350'
 Or in  the 100 parts,
        Lithia,                 45.54
         Carbolic acid,          54.46
                              100.00
 But the oxygen in
          45.51 lithia is        --= 19.09
          54.46 carbonic acid   =^ 39.59
 and 2 X  ll->.<>9 -- 38.18,  a number differ-
 ing but little from 39.59.
    The solution of carbonate of lithia is de-
 composedby lime and ban tes-water.  It is
 insoluble in alcohol.
   The platinum crucible in which carbonate
 of lithia has been exposed toared heat, gives
 obvious indications of having been attacked,
 its surface assuming a dark olive-green co-
 lour;  but the metallic  lustre is again restor-
 ed by rubbing the crucible with coarse sand
 and water.
   Muriate of lithia forms small regular cubes
 very similar to common  salt in  their taste.
 The easiest method of obtaining the crystals,
 is to expose the solution to the sun in a hot
 day.  The crystals deliquesce very speedily
 when exposeel to  the air, but not with  so
 much rapidity as nitrate of lithia. This salt
 does not  melt when exposed to the red heat
 produced by the action of a spirit lamp; but
 when exposed in a platinum crucible, not
 completely covered, to an incipient white
 heat, it is fused into the chloride.
   Chromute  of lithia forms orange-yellow
 crystals, which appear  to contain an  excess
 of acid.   They are oblique paralldopipeds
 with rhomboidal bases.  Sometimes they ex-
 hibit a dendritical vegetation.   This salt is
 soluble in water.
   Oxalate of lithia.—A  portion of carbonate
 of lithia  was  saturated  with oxalic acid.
 The neutral salt crystallizes with difficulty.
 The crystals have the  appearance of small
 opaque protuberances,  and dissolve with fa-
 cility in water. To the neutral solution  of
 oxalate of lithia was added a quantity  of
 oxalic acid, exactly  equal to  that already-
 combined with the lithia.   By evaporation,
 small transparent granular crystals of bino.ra-
 late of lithia were obtained.  They appeared
 to dissolve with facility  in water, though not
 to be so soluble as the neutral salt.
  Neutral tartrate of lithia dissolves with
 facility in  water, but does not crystallize,
 forming a white opaque mass, which does
 not  deliquesce when  exposed to the air.
 When tartaric acid is added to the solution
 of the neutral tartrate,  no crystallizable hi-
 tartrate is formed; but  perhaps we may de-
 duce the existence of such a salt from the
 fact, that when the solution is evaporated, no
 crystals of tartaric acid make their appear-
 ance.
  W hen the solution is evaporated to dry-
 ness, we obtain a white  opaque mass,  which
 exhibits  no appearance of crystallization,
 and  which dissolves with facility in wa-
 ter.
  Acetate  of lithia,  when evaporated,  forms
 a sirupy mass, which cracks on cooling;  so
that the glass looks as if it had burst.  T his
matter deliquesces in the air, and sometimes, 
LIT
LIT
 while attracting moisture, crystalline plates
 appear in it.
   Tartrate of lithia  and potash.—If the ex-
 cess of acid of bitartrate  of potash be satu-
 rated  by means of carbonate of lithia, we
 obtain, by spontaneous evaporation, a salt
 which forms large crystals, having the shape
 of four sided prisms terminated by parallelo-
 grams, with angles very nearly right.  The
 diagonals of these terminal faces are distinct-
 ly marked, and the four triangles formed by
 means of them are streaked parallel <o the
 edges of these faces.   This  salt dissolves
 readily in water, and has a saline and scarce-
 ly bitter taste.   When exposed to the air, it
 effloresces slightly, and  only on the sur-
 face.
   Tartrate of lithia and soda. - Bitartrate of
 soda was neutralized by means of carbonate
 of lithia.   By spontaneous evaporation, the
 liquid deposited long rectangular four-sided
 prisms, frequently terminated by an oblique
 face.  This salt dissolves  with facility in wa-
 ter, and effloresces only slightly, and on the
 surface.  Its taste is purely saline,  and not
 strong.
   Muriate of platinum does not form a double
 salt w ifh muriate of lithia. Potash and lithia,
 therefore,  may be  very well distinguished
 from each other by means of muriate of pla-
 tinum.
   From the preceding account of the salts of
 lithia,  we see that they have many properties
 in common with the salts of soda.  Like
 them,  they are neither precipitated by mu-
 riate of platinum, nor by tartaric acid. They
 may, however, be distinguished from the
 salts of soda by the following properties :
 When theirconcentratedsolutions are mixed
 with a concentrated solution of carbonate of
 soda, a precipitate falls.  They are likewise
 precipitated by phosphate of soda and phos-
 phate  of ammonia,  when no uncombined
 acid is present.
  In reference to analytical chemistry, it may
 be remarked, that lithia, potash and  soda, if
 they should exist in the same compound, may
 be separated in the following way :—
  Lithia may be precipitated  by means of
 phosphoric acid and an  excess  of caustic
 ammonia.  The phosphate of lithia may be
 dissolved in acetic acid, and the phosphoric
acid precipitated by means of acetate of lead,
 &c.
  When lithia exists in a compound with
potash, this last alkali may be precipitated
by means of muriate of platinum.
  l^om the results of the preceding experi-
ments, we see,  says Dr. Gmelin,  that if 10
be the equivalent number for oxygen, the
equivalent number for lithium is  13.83, and
for lithia 25.83; that for carbonate of lithia
by calculation 51.32; but, according to the
preceding experiment, 52.32, &c.
  Placed in the voltaic circuit, Sir II. Davy
 showed, that it was  decomposed with the
same phenomena as the other alkalis.  A
portion of its carbonate being fused in a pla-
tinum capsule, the platinum was rendered
positive, and a negative wire brought to the
upper surface. The alkali decomposed with
bright scintillations, anel the reduced metal
being separated, afterwards burned.  The
particles were very similar to sodium.  A
globule of  quicksilver made negative, anel
brought into contact with the alkaline salt,
soon  became an amalgam of lithium, and
had gained the power of acting on  water,
with the evolution of hydrogen, and  forma-
tion of alkali.
  M. Vauquelin concludes from his experi-
ments, that 100 parts of lithia contain 43. 5
of oxygen, and 56.5  of metallic base; a
quantity which, he observes, is greater than
that of all the other alkalis.  The Editors
ofthe Ann. de Chimie remark, that accord-
ing to this estimate, the  equivalent number
of the metal is 12.97, of its oxide 22.97.  of
its dry sulphate 72.97, and of its crystallized
sulphate 82.97.   These numbers are adapt-
ed to the oxygen radix of 10.  Dr.  Gmelin's
analysis of  lithia, makes its composition  to
be, by his own reduction,
          Lithium,     58.05
           Oxygen,     41.95
                      100.00
 His neutral sulphate consists of
              Crystallized. Dry.
   Sulphuric acid,  58.34  68.15    5.000
   Lithia,          27.2.5  31.85    2.3367
   Water,          14.41
 The prime equivalent of lithia inferred from
 this analysis, approaches much nearer to M.
 Vauquelin's number, than that deduced by
 Dr. Gmelin  himself.   If we convert this
 prime ratio into per cent proportions, we shall
 have lithia a compound,
      Of Lithium,  57.205  1.3367
         Oxygen,  42.795  1.0000
   From his analysis of the carbonate, the
 prime equivalent of lithia comes out, as near-
 ly as possible, 2.3.  We are therefore war-
 ranted to consider 1.3 as the prime of lithium,
 from the concurring experiments, both of M.
 Vauquelin  and Dr. Gmelin.  I cannot see
 how the Doctor's own  ingenious and accu-
 rate experiments on these two salts, permit-
 ted him to make so erroneous an estimate of
 the equivalent of lithia, as 23.83, instead of
 23j or 23.*
  ♦Lithic Acm.  See Acin (Lithic).*
  ♦LiTHOMAnoi;.  Stone-marrow, a mineral
 of which there are two  kinds, the friable,
 and the  indurated.
  Friable  Lithomarge.  Colour white, mas-
 sive, and  sometimes in crusts.   Particles
 scaly, and feebly glimmering.  Streak shin-
ing.  Slightly  cohering.   Soils  slightly.
Feels rathergreasy. Aelhcrcstothe tongue.
Light Phosphoresces in the dark. Its con-
stituents are,  silica 32, alumina  26.5,  iron 
LOG
LUT
21, muriate of soda 1.5, and water 17.0—
Klaprolh.   It occurs commonly in tin-stone
veins.
  Indurated Lithomargr.   Colours, yellow-
ish and reddish-white." Massive, and amyg-
daloidal.   Dull.   Fracture,  fine earthy.
Opaque   Streak shining.  Soft, sectile, and
easily frangible.   Adheres  strongly to the
tongue.  Feels fine, and greasy.  Sp. grav.
2.44. Infusible before the blow-pipe ;• some
varieties phosphoresce, and others, when
moistened, afford an agreeable  smell like
that of nuts.   Its constituents are, silica
45.25,  alumina 36.5,  oxide of  iron 2.75.
water 14,  and a trace of potash.—Klaproth.
It occurs in veins in prophyry, gneiss, &c.
at Rochlitzin Saxony, andat Zoblitz.—Jame-
son.4
  Litmus.  Sec Aucuit,.
  Liver of Silfhlh.   See Sulphur.
  Lixiviatiov.   The application of water
to the fixed residues of bodies, for the pur-
pose of extracting the saline part.
   Lixivium.  A solution obtained by lixivi-
ation.
   Loahstoxe.  See Ores of Iron.
   * Loam.   Sec Clay.*
  Logwood.  The tree which yields it  is
called  by  Linnaeus, Haematoxylum campe-
chianum.
   Logwood is so heavy as to sink in water,
hard, compact, of a fine grain, capable  of
being polished, and scarcely susceptible of
decay.  Its predominant colour is red, ting-
ed with orange, yellow, and black.
   It yields its colour, both to spirituous and
watery menstrua.  Alcohol extracts it more
readily and copiously than water.  The co-
lour of its dyes is a fine red, inclining a lit-
tle to violet or purple, which is principally
observable in its watery decoction.  This,
left to itself, becomes in time yellowish, and
at length black.  Acids turn it yellow ;  al-
kalis deepen its colour, and give it a purple
or violet hue.
   Stuffs would take only a slight and fading
 colour from decoction of  logwood, if they
 were not previously prepared with alum and
tartar.   A little  alum is added also to the
 bath.  By these means they acquire a pretty
 good violet.
   A blue colour may be obtained from log-
 wood, by mixing verdigris with the bath,
 and dipping the cloth till it has acquired the
 proper shade.
   The great consumption of logwood is  for
 blacks, to which it gives a lustre and vel-
 vety cast, and for grays of certain shades. It
 js also of very extensive  use for different
 compound colours, which  it would be diffi-
 cult to obtain of equal beauty and variety,
 by means of drugs affording a more perma-
 nent dye.
   juice of logwood is frequently mixed with
 that of brasil, to render colours deej>er;
their  proportion being \aricd according to
the shade desired.
  Logwood is used for dyeing  silk, violet.
For this, the silk must be scoured, alumed,
and washed; because,  without  ahuning, it
would take only a reddish tinge, that would
not stand wetting.  To dye silk thus, it
must be  turned in a cold'decoction ot log.
wood, till it hasjicquiredthc proper colour:
if the decoction were  used hot, the colour
would be in stripes and uneven.
  Bergmann has already observed, that a fin;.
violet mi;;lit be produced from logwood,  by
impregnating the silk  with solution of tin.
In fact, we may thus obtain, particularly  by
mixing  logwood  and brasil in various pro.-
portions, a great number of fine shades, more
or less inclined to red, from lilac to \iolet.
See Hematin.
  * Lomomtk, or Laumoniti. Di-prismatic
Zeoliik.*
  •Lucullite.  See Limf.stoxk, 10th spe-
cies.*
  LUMACHF.LI.A.  See LlMKSTONF..
  Luna Coiini:a.   Muriate of silver.  See
Silver.
  Lunar Caustic.  Nitrate of silver, fused
in alow  heat.  See Silver.
  Lutk. The lutes with which  the joinings
of vessels are closed, are of different  kind*,
according to the nature of the operations to
be made, and of the substances to be dis-
tilled in these vessels.
   When vapours of watery liquors,and sftch
as are not corrosive, are to  be contained, it
is sufficient to surround the joining  ofthe
receiver to the nose ofthe alembic, or of
the retort, with slips of paper or of linen,
covered with flour-paste.   In such  cases
also slips of  wet bladder are very conve-
niently used.
   When more  penetrating and  dissolving
 vapours are to be contained, a lute is to be
 employed of quicklime slackeel in the  air,
 and beaten into a liquid paste with whites of
 eggs. This paste is to be spread upon linen
 slips, which are to be applied exactly to the
 joining ofthe vessels. This lute is very con-
 venient, easily elries, becomes solid,and suf-
 ficiently firm.  Of this lute, vessels may be
 formed  hard enough  to  bear polishing on
 the wheel.
   Lastly,  when acid and corrosive vapours
 are to be contained, we must then have re-
 course to the lute called fat lute.   This  lute
 is made by forming into a  paste some dried
 clay finely powdered, sifted through a silken
 searce, and moistened with water, and then
 by "beating this paste well  in a mortar with
 boiled linseed oil, that is, oil which has been
 rendered drying by litharge dissolved in it,
 and fit  for the use of painters.   This  lute
 easily takes and retains the  form given to
 it.  It is generally rolled into cylinders of a
 convenient size.    These are to be applied, 
MAI)                                  MAD
by flattening them, to the joinings ofthe ves-
sels, which oughtto be perfectly dry, because
the least moisture would prevent the lute
from adhering.   When the joinings are well
closed with this fat lute, the whole is to be
covered with slips of linen spread with lute
of lime and whi; es of eggs.  These slips arc
to be fastened with packthread.  The se-
cond  lute is necessary to keep on the fat
lute, because this latter  remains soft, and
does not become solid enough to stick on
alone.
  Fine porcelain clay, mixed with a solution
of borax, is well adapted to iron vessels, the
part received into an aperture being smear-
ed with it.
  Ltcopohium.   The fine dust of lycopodi-
um, or clubmoss, is properly the seeds ofthe
plant, and when diffused or strewed  in the
air, it takes lire from a candle, and burns off
like a flash of lightning.  It  is used  in the
London theatres.
  * Lyiiiav Stove.  Flinty  slate.*
  * I.ytiiuodf.s.  See Scai'olitk,*
M
     MACERATION.  The steeping of a bo-
      dv in a cold liquor.
  Madhkr, a substance very extensively em-
ployed in  dyeing, is the root of the rubia
tinctorum.
  Although madder will grow both in a stiff
cla\ey soil, and in sand, it succeeds better in
a moderately rich, soft, and somewhat sandy
soil: it is cultivated in many of the provinces
of France, in Alsace, Normandy, and Pro-
vence : the best of European growth is that
which comes from Zealand.
  The best roots are about the thickness of
a goose quill, or at most ofthe little finger;
they are semi-transparent, and of a reddish
colour; they have a strong smell, and the
bark is smooth.
  Hellot ascribes the superiority ofthe mad-
der which comes from the Levant to the cir-
cumstance of its having been dried in the
open air.
  The reel colouring matter of madder may
be dissolved in alcohol, and on evaporation,
a residuum of a deep red is left.  Fixed al-
kali forms in this solution a  violet, the sul-
phuric  acid a fawn-coloured, and the sul-
phate of potash a fine red precipitate.  Pre-
cipitates of various shades may be obtained
by alum, nitre, chalk, sugar of lead, and the
muriate of tin.
  The quantity ofaqueouschlorine required
to destroy the colour of a decoction of mad-
der, is double what is necessary to destroy
that of a decoction of an equal weight of
brazil wrood.
  Wool would receive from madder only a
perishable dye,  if the colouring particles
Mere not  fixed by a base, which occasions
them to combine with the stuff more inti-
mately, and which in some measure defends
them from the destructive influence of the
air.   For  this purpose, the  woollen stuffs
are first boiled for two or three hours with
alum and  tartar, after which they are left to
drain;  they are then slightly wrung and
put into a linen bag, and  carried into a cool
place, where they are suffered to remain for
some days.
   The quantities of alum and tartar, as well
as their proportions, vary much in different
manufactories.  Uellot recommends five
ounces of alum and one ounce of tartar to
each pound of wool.  If the proportion of
tartar be increased to a certain degree, in-
stead of a red, a eleep and durable cinnamon
colour is proeluced;  because,  as we have
seen, acids have a tendency  to give a yel-
low tinge to the colouring particles of mad-
der.  Berthollet found, that, by emploving
onerhalf tartar, the colour sensibly bordered
more on the  cinnamon than when the pro-
portion was only one-fourth of the alum.
  In dyeing with madder,  the bath  must
not be permitted to boil, because  that de-
gree of heat would dissolve the  fawn-co-
loured particles, which are less soluble than
the red, and the colour would be  different
from that which we wish to obtain.
  The quantity of madder which Mr. Poer-
ner employs is only one-third ofthe weight
ofthe wool, and Schaeffer advises only one-
fourth.
  If wool be boiled for two hours with one-
fourth of sulphate of iron, then washed, and
afterward putintocoldwaterwith one-fourth
of madder, and then  boded for an hour, a
coffee colour is produced.  Bergmann adds,
that, if the wool have not been soaked, and if
it be dyed with one part of sulphate of iron
and two of madder, the brown obtained bor-
ders upon a red.
  Berthollet  employed a solution  of tin in
various ways, both in the preparation and in
the maddering of cloth.  He used different
solutions of tin, and found that the tint was
always more yellow or fawn-coloured,though
sometimes  brighter than that obtained by
the common process.
   Mr. Guhliche describes a process for dye-
ing silk with madder: for one pound of silk
he orders a bath of four ounces of alum, and
one ounce of a solution of tin; the liquor is
to be left to settle, when it is to be decanted,
and the silk carefully soaked in it, and left
for twelve hours; and after this preparation,
it is to  be immersed in a  hath containing
half a pound of madder softened by boiling
with an infusion of galls in white wine j this 
MAD                                  MAD
 bath is to be kept moderately hot for an
 hour, after which it is to be made to boil for
 two minutes.  When taken from the bath,
 the silk is to be washed in a stream of wa-
 ter, and dried in  the  sun.   Mr. Guhliche
 compares the Cjlour thus obtained, which is
 very permanent, to the Turkey-red.  If the
 galls be left  out, the colour is clearer.   A
 great degree of brightness may be commu-
 nicated to the first of these, by afterward
 passing it through a bath of brazil wood, to
 which one ounce of solution of tin has been
 added  the  colour thus obtained, he says,
 is very beautiful and durable.
   The madder red of cotton  is elistinguished
 into two kinds : one is called simple madder
 red;  the other, which is much brighter, is
 called Turkey  or  Adnanople ted, because
 it comes from the  Levant, and has seldom
 been equalled in brightness or durability by
 our artists.
   Galls or sumach dispose thread and cotton
 to receive the madder colour, and the pro-
 per mordant is acetate of alumina.
   The nitrate and  muriate of iron as a mor-
 dant, produces a better effect than the sul-
 phate and acetate  of the same metal; they
 afford a beautiful, well saturated violet co-
 lour.
  The Adrianople red possesses a degree of
 brightness, which it is difficult for us to ap-
 proach  by any of the processes hitherto
 mentioned,
   Some years ago, Mr. Papillon set up a
 dyehouse for this red at Glasgow ;  and in
 1790 the commissioners for manufactures in
 Scotland paid him a premium, for communi-
 cating his process to the late Prof- Black, on
 condition of its not being divulged for a cer-
 tain term of years.   The time being expired,
 it has been made public, and is as follows:—
  Step.  I.—For 100 lbs. of cotton, you must
 have 100 lb. of Alicant barilla, 20 lb. of pearl
 ashes, 100 lb. of quicklime.
  The barilla is to  be mixed with soft water
 in a deep tub, which has a small hole near
 the bottom of it, stopped at first with a peg.
 This hole is to be covered in  the inside with
 a cloth  supported  by two bricks, that the
 ashes may be prevented  from running out
 at it, or stopping it up, while the ley filters
 through it. Under this tub must be another,
 to receive the ley,  and pure water is to be
 passed repeateelly  through the first tub, to
 form leys of  different  strength, which are
 kept  separate until their strength  is ex-
 amined. The strongest  required for use
 must float an egg, and  is  called the ley  of
 six degrees ofthe French hydrometer. The
 weaker are  afterwards  brought to this
strength by  passing  them  through fresh
barilla;  but a certain quantity of the weak,
which is of two degrees of the above hydro-
meter, is reserved for dissolving the oil, the
gum, and the salt, which are used in subse-
quent parts ofthe process. This ley of two
 degrees is called the weak barilla liquor ;
 the other the strong.
   Dissolve the pearl  ashes  in  ten pail <_, of
 four gallons each, of soft water, and the
 lime in fourteen pails.
   Let all the liquors  stand till they become
 quite clear, and then mix. ten pails of each.
   Boil the cotton in this mixture five hours,
 then wash it in running water,  and dry it.
   Step  II. Bain bis, or Gray steep.—Take a
 sufficient quantity (ten pails) of the strong
 barilla water in a tub, and mix with it two
 pailfuls of sheep's dung; then pour into it
 two  quart  bottles of sulphuric  acid, one
 pound of gum-arabic, and one pound of sal
 ammoniac, both previously dissolved in a
 sufficient quantity of weak  barilla water;
 and,  lastly, twenty-five pounds of  olive oil,
 previously dissolved, or well mixed with two
 pails ofthe weak barilla water.
   The  materials of this steep  being well
 mixed, tread down the cotton into it until it
 is well soaked; let  it steep  twenty-four
 hours, then wring it hard and dry it.
   Steep it  again twenty-four hours, and
 again wring and dry it.
   Steep  it a third time twenty-four hours,
 after which wring anel dry it; and, lasdy,
 wash it well and dry it.
   Step. III.   The white steep.—This part of
 the process is precisely the same with the
 last  in every  particular,  except  that the
 sheep's dung is omitted in the composition
 ofthe steep.
   Step.  IV.  Gall steep.~Bo\l  twenty-five
 pounds of bruised galls in ten pails of river
 water, until four or five  are  boiled away;
 strain the liquor into  a tub, and pour cold
 water on the galls in the strainer to wash
 out of them all their tincture.
   As soon as the liquor is become milk-
 warm, dip your cotton, hank by hank, hand-
 ling it carefully all the time, and let it steep
 twenty-four hours. Then  wring  it care-
 fully  and equally, and dry it well without
 washing.
   Step. V. First alum steep.—Dissolve twen-
 ty-five pounds of Roman  alum in fourteen
 pails of warm water, without making it boil,
 scum the liquor well, add two pails of strong
 barilla water, and then let it cool until it is
 lukewarm.
   Dip your cotton, and handle  it hank by
 hank, and let, it steep twenty-four hours;
 wring it equally, and dry it well  without
 washing.
   Step.  VI.   Second  alum  steep.—This  is
 in every particular like the last; but after
 the cotton is dry, steep it six hours in the
 river, and then wash and dry it.
   Step. VII.   Dyeing steep. - The cotton is
 dyed by about ten pounds at once, for which
take about two gallons and a half of bul-
locks' blood, mix it in the copper with twen-
ty-eight pails of milk-warm  water, stir it
well, add twenty-five pounds of madder, and 
MAG                                  MAG
lastly, stir aH well together.  Then having
beforehand put  the cotton on sticks, dip it
into the liquor,  and  move and turn it con-
stantly one hour,  during which gradually
increase the heat until the licpior begins to
boil at the  end ofthe hour.  Then sink the
cotton, and boil it  gently one hour longer;
and lastly wash it and dry it.
   Take out so much ot the boiling liquor,
that what remains may produce a milk-warm
heat  with  the fresh  water with which the
copper is again filled up, and then proceed
to make up a dyeing liquor,  as above, for
the next ten pounds of cotton.
   Step. VIII.   The fixing steep.—Mix equal
parts  of the gray steep  liquor and of the
white steep liquor,  taking five or six pails
of each.  Tread down the cotton into this
mixture, and  let it  steep six hours: then
wring it moderately  and equally, and dry it
without washing.
   Step. IX. Brightening steep.—Ten pounds
of white soap must be dissolved very care-
fully and completely in sixteen or eighteen
pails of warm water: if any little bits of the
soap  remain undissolved,  they will make
spots in the cotton. Add four pails of strong
barilla water, and stir it well.  Sink the cot
ton in  this liquor, keeping it  down with
cross sticks, and cover it up;  bod it gently
two hours, then wash it  and  dry it, and it
is finished.
   * Madrepores.  A species of coral, the
zoophyte   of naturalists.  They consist of
carbonate of lime, and a little animal mem-
branaceous substance.*
   Magistert.   Chemists formerly applied
this term to almost all precipitates: at pre-
sent it is applied only to  a few, which have
retained the name from habitual usage.
   Magisterx of Bismuth.  See Bismuth.
   * Magnesia. One of the primitive earths,
having a metallic  basis, called magnesium.
It has been found native in the state of hy-
drate.
   Magnesia may be  obtained, by  pouring
into a solution of its  sulphate, a solution of
subcarbonate of soda, washing the precipi-
tate, drying it, and exposing it to a red heat.
It is usually procured in commerce, by act-
ing on magnesian limestone with the impure
muriate of magnesia, or bittern of the sea-
salt manufactories.  The muriatic acid goes
to the lime, forming a soluble salt, and leaves
behind, the magnesia of both the bittern and
limestone.  Or the bittern is decomposed by
a crude subcarbonate of ammonia, obtained
from the distillation  of bones in iron cylin-
ders.  Muriate of ammonia and subcarbonate
of magnesia result. The former is evaporat-
ed to dryness, mixed  with chalk andsublim-
ed,  Subcarbonate of ammonia is thus reco-
vered, with which a new quantity of bittern
may be decomposed; and thus in ceaseless
repetition, forming an elegant and economi-
cal process. 100 parts of crystallized Bpsom
salt, require for complete decomposition 56
of subcarbonate of potash, or 44 dry subcar-
bonate of soda, and y ield 16 of pure magne-
sia after calcination.
  Magnesia is a white, soft powder.   Its sp.
gr. is 2.3 by Kirwan.  It renders the sirup
of violets, and infusion of red cabbage, green,
and reddens turmeric.  It is  infusible, ex-
cept by the hydroxy gen blow-pipe.  It has
scarcely any taste, and no smell.  It is near-
ly insoluble in water; but it absorbs a quan-
tity of that liquid  with  the production  of
heat.  And when it is thrown down from
the sulphate by a caustic alkali, it is combin-
*ed with water constituting a hydrate, which,
however, separates  at a  red heat.  It  con-
tains about one-fourth its weight of water.
  When magnesia is exposed to  the air, it
very slowly attracts carbonic acid  It com-
bines with  sulphur, forming a sulphuret.
  The metallic basis, or magnesium, may be
obtained in the state of amalgam  with mer-
cury, by electrization, as is described under
Barium; but a much longer time is neces-
sary.   Sir  H. Davy  succeeded also in de-
composing magnesia, by passing  potassium
in vapour through it, heated to whiteness,
in a tube of platinum out of the contact of
air.  He then introduced a small quantity
of mercury, and heated  it gently for some
time in the tube.  An amalgam was obtain-
ed, which,  by distillation, out of the contact
of the atmosphere, afforded a dark-gray me-
tallic film,  infusible  at the  point at which
plate-glass  softened, and which in the  pro-
cess of the distillation ofthe mercury, ren-
dered the glass black at  its point  of contact
with it.  This film burned with a red light
when heated strongly, and became convert-
ed into a white powder, which had the cha-
racter of magnesia.  When  a portion  of
magnesium was  thrown  into water, it sunk
to the bottom, and effervesced slowly, be-
coming covered  with a white  powder.  By
adding a little muriatic  acid to the water,
the effervescence was violent. The metal
rapidly disappeared, and the solution was
found to contain  magnesia.  No direct ex-
periments have as yet been made, to deter-
mine the proportions of the  elements  in
magnesia;  but from experiments  made on
the combination of this substance with sul-
phuric acid, assuming that they are in single
proportions, Dr. Wollaston infers the equi-
valent of magnesia to be  2.46.  Hence mag-
nesium will be  1.46.  M. Gay-Lussac has
lately experimented, with his characteristic
accuracy, on the  sulphate of magnesia, and
finds it, when  crystallized, a compound of
dry sulphate of magnesia,       48.57
                 water,       51.43
  The equivalent number for the dry sul-
phate is 7.47129, whence that  for  magnesia
is 2.47129,  approaching  very nearly to Dr.
Wollaston's determination.
  When magnesia is strongly heated in con- 
MAG                                 MAL
tact with 2 volumes of chlorine, this gas is
absorbed, and 1 volume of oxygen is disen-
gaged  Hence it is evident that there ex--
ists a  combination of magnesium and chlo-
rine, or a true chloride.  1'he salt called
muriate of imigiitsia, is a compound of the
chloride  and water.  W hen it is  acted  on
by a  strong heat, by far the greatest part
of the chlorine unites to the hydrogen of
the water, anel rises in the form of muriatic
acid gas; while the oxy yen of the decom-
posed water, combines witli the magnesium
to form magnesia.
  Magnesia is often associated  with lime in,
minerals, and their perfect separation be-
comes an interesting  problem in analysis.
M. Longchamp has published a valuable pa-
per on the subject, m the 12th volume ofthe
Ann.  ds Chim. et Phys.
  He considers subcarbonate of ammonia as
the best reagent  for separating the two
earths.  Care must be taken to filter the so-
lution from the calcareous precipitate, short-
ly after the addition of the subcarbonate.
If it stand 12 or 18 hours, subcarbonate of
magnesia falls with the carbonate of lime.
1U0 parts of solution of pure muriate of lime
gave, with subcarbonate of ammonia, 1.5475
parts of carbonate of lime:  100 ofthe same
solution, previously   mixed with  muriate
of  magnesia  in  excess,  yieldeel  1.5585
parts.   Alkaline  subcarbonates  dissolve
the  subcarbonate  of magnesia ;  but caus-
tic potash precipitates magnesia  perfect-
ly, either  with or without heat.  He  ob-
jects  to the method of separating these
earths, by first converting them into sul-
phates; first, on account ofthe great diffi-
culty of driving off the water from  the
sulphates of magnesia:  secondly, from  the
difficult solubility of heated and  dry  sul-
phate of magnesia in water;  and, thirdly,
because the sulphate of magnesia is partly
decomposed at very high heats.
   Magnesia is chiefly used as an antacid,
purgative, and lithontriptic in medicine.
 When incautiously used for a lonj* time, it
 may produce very serious evils, ot which a
 remarkable case is narrated by Mr. Brande,
 in the 1st volume of his Journal.  A lady
 was recommended to take magnesia, in con-
 sequence of some very severe nephritic at-
 tacks, accompanied with the passage of gra-
 vel.  She was desired to take a tea-spoonful
 every night;  and Henry's calcined magne-
 sia was preferred, as that always operated
 upon the bowels, and "carried  itself off,"
 which other magnesia  did not, but, on the
 contrary, felt heavy and uneasy in the sto-
 mach. The dose u as gradually increased to
 two tea-spoonfuls, in order to produce effect
 upon the bowels, which this quantity never
 failed to do.  The symptoms for which it
 was ordered,  were  soon removed, but the
 plan was persevered in for two years and a
 halt; with little intermission;  so that as the
average weight of a tea-spoonful is at least
40 grains, and the average  dose was a tea-
spoonful and a half;  it may be presumed
that she took, during the above period, be-
tween 9 anel  10 pounds troy.   "In  the
course ofthe last autumn, she became sensi-
ble of a tenderness in the let': side, just above
the groin, connected with  a deep scaled
tumour, obscurely to be felt upon pressure,
and subject to attacks of constipation,  with
painful spasmodic action ofthe bowels, tenes-
mus, and a highlyr irritable state of stomach.
These attacks recurreel every two or three
weeks, varyingin violence, but requiring the
use of active remedies.  Several  irregular
lumps, of a soft light brown  substance, were
voided, havingthc appearance of a large mass
broken down, and when dry extremely fri-
able.  A part of each was subjected to ana-
lysis, and found to consist  entirely of sub-
carbonate of  magnesia, concreted  by the
mucus of the bowels, in the proportion of
about 40 per cent.   She was cured by the
use of other purgatives."  Another case is
mentioned,  in which not only large quanti-
ties of a concretion of a similar description
 were  voided, but upon  examination  after
 death, which took place perhaps six months
 if ter any magnesia had been  taken, a col-
 lection, supposeel to be from four to  six
 pounds, was found imbedded in the  head
 of the colon, which was of course much dis-
 tended.
   The most important magnesian salts are
 described under the acids.*
   * Magnesi i (Hyd it ate of).  This mine-
 ral was found by Dr. Bruce of New York,
 in  small veins in serpentine at Hoboken, in
 New Jersey. Colour white. Massive.  Lus-
 tre pearly.   Fracture foliated or radiated.
 Semi-transparent in  the mass ; transparent
 in single folia.  Soft, and somewhat elastic.
 Adheres slightly to the tongue. Sp. gr.2.13.
 Soluble in acids.  Its constituents are mag-
 nesia 70, water 30, which  approaches to 1
 prime equivalent of each.- Jameson.*
    * Magnesian Limeston;:. See Dolowite.*
    *M\gnesite.  Colour yellowish-gray, or
 yellowish-white, and marked with spots. It
 occurs massive, tuberose, reniform, and vesi-
 cular. Surface rough.  Dull.  Fracture con-
 choidal.  Fragments rather sharp-edged.
 Opaque.  Scratched  by  fluor spar,  but it
 scratches calcareous spar.  It adheres pretty
 strongly to  the tongue.   It  feels rather
 meagre.  Streak dull.  Rather easily fran-
 gible.  Sp. gr.  2.881.  Infusible; but be-
 fore the blow-pipe it becomes so hard as to
 scratch glass.  Its constituents are, 46 mag-
  nesia,  51  carbonic acid,  I  alumina,  0.25
 ferruginous manganese, 0.16 lime, 1  water.
 __hncholz.   It is found at Hrubschitz in
  Moravia, in serpentine rocks.*
    * Magnetic Iron Ore, and Pithites. See.
  Oues of Iron.*
    ♦ MALAtairs.  See Ores or Copper * 
MAST                                 MAN
    * Malacolite.  Sahlite.*
    * Malates and Malic  Acin.   See Acid
  (Sorbic).
    * Malleability.  See Ductility.*
    :; Maltha.   The  mineral tallow of Kir-
  wan, said to have been found on the coast of
  Finland.  It resembles wax.  Its sp. gr. is
  0.77.  It is white,  brittle, stains  paper like
  oil, melts with a moderate heat, and burns
  with a blue flame and much smoke.  It dis-
  solves readily in oil, and imperfectly in hot
  alcohol.*
    Manganese.  A metal  of a dull whitish
  colour when broken, but which soon grows
  dark by oxidation,  from the action of the air.
  It is hard, brittle,  though  not puherizable,
  and rough in its fracture ;  so difficultly fusi-
  ble that no heat yet exhibited has caused it
  to run into masses of any considerable mag-
  nitude.   Its sp. gr. is 8.0.  When broken
  in pieces, it falls into a powder by spontane-
  ous oxidation.
    * Manganese heated in oxygen, or  chlo-
  rine, takes fire and forms an oxide or  ciilo-
  ride.  It is difficult to decide on the oxide-s
  ofmanganese.                      .;
    According to Sir H.  Davy there are two
  oxides  only, the olive and the  black; Mr.
  Brande has three, the olive, dark-red, and
  black ;  M. Thenard has four, the green, the
  white (in the state of hy drate), the chesnut-
  brown, and  the black; Berzelius  has five,
  the first  gray, the  second green, the third
  and fourtli are not  well defined, and the fifth
  is the black.
   In this perplexity it will be prudent to
  rest on the authority of Sir H. Davy.
   1.  The first oxide may be ob ained by
  dissolving common black manganese in sul-
  phuric or nitric acid, adding a little sugar,
  and precipitating by solution of potash.  A
  white power  is obtained, which being heat-
  ed to redness out  ofthe contact of air, be-
  comes yellow, puce-coloured, and lastly red-
  brown. To be preserved, it should be wash-
 ed in boiling water, previously freed from
 air, and then dried  by distilling off'the mois-
 ture in a retort filled with hydrogen.  Tlie
 dark olive oxide, when examined in large
 quwitities, appears  almost black;  but when
 spread upon white  paper, its olive tint is ap-
 parent.   It takes fire when gently heated,
 increases in weight, and acejuires a browner
 tint.  It slowly absorbs oxygen from the air,
 even at common temperatures.  It dissolves
 in acids without effervescence.   The white
 powder obtained above, is the hydrated prot-
 oxide.  The different tints which it assumes
 by exposure to air, are ingeniously supposed
 by Sir H. Davy, to depend on the forma-
 tion of variable quantities ofthe black-brown
 oxide, which probably retains the water con-
 tained in the  white  hydrate, and  is hence
 deep puce-coloured.
  2. I he black peroxide.  Its sp, gr. is 4. It
does not combine with any of the acids.  It
yields oxygen when heated; and by intemse
   Von. ik.
  ignition passes in a gneat measure into the
  protoxide.  According to Sir H. Davy, the
  olive oxide consists of
        Manganesium,       -    79
        Oxygen,   -    -    -    21
  And the black oxide, of
        Manganesium,            69
        Oxygi-n, about  -    -    31
   He  considers the first  as a deutoxide,
  whence the prime equivalent is inferred to
  be 7.533.
  The olive oxide,       7.533 met.-|-  2 ox.
  Or,                 80.        -j- 20.
  The black oxide will be, 7.533     +  3.
  Or,    -    -    -    71.5       +28.5.
  The compound of the
   first  with water is a
   deutoh) drate, or     7.533    -f-2.25w.
   The  olive oxiele becomes green by the ac-;
  tion of potash, whence Sir  H. accounts for
  the mistakes of chemists relative to a green
  oxide.  In this case there is a combination.
  See Cameleox Mneral.
   Dr. Thomson pitches on the number 3.5
  for the atom of manganese, from  the re-
  searches of John and Berzelius.  The con-
 fidence due to his authority in this case may
 be judged of from the following narrative :
  " Dr. John acknowledges, that his analyses
 or these oxides is by no means to be depend-
 ed on.  Berzehus's statement is ra her theo-
 retical than exper.mental.  He even doubts
 ofthe  existence of his first oxide, the only
 one he  examined; and he has advanced no
 proof that there exists any difference be-
 tween his second and third oxide."—'Hence
 it is evident, that protoxide  (the green ox-
 ide of John) ofmanganese is composed d'
        Manganese,    3.5     100
        Oxygen,       1.       28.75
   " This  very nearly  coincides with Ber-
 zehus's third oxide.  And  in reality his
 third oxide is the protoxide of manganese."
 System,  vol. i. pp. 4i>3 and 404. 5th ed.
   He takes his proportions in the peroxide,
 from  Uerzelius's "theoretical considera-
 tions," to  the exclusion  of  Sir II.  Davy's
 "experiments."  The  perchloiide may be
 conveniently obtained by igniting the mu-
 riate  of manganese.   It  thus appears as a
 pale pink-coloured substance, seini-transpa-
 rent.and in brilliant scales. It is acompound
 of 7.533 metal 4- 9 chlorine, from the ex-
 periments  of Dr. John Davy.  Probably a
 protochloride may be formed.
   Sir H. Davy  is inclined to believe, that
 the olive oxide is the only one which  enters
into combination with verifiable substances.
   The salts of manganese have been little
studied.  They are mostly soluble in  water.
Ferroprussiale of potash gives a white pre-
  cipitate.
Hydrosulphuret,      -    -     white
Sulphuretted hydrogen,   .       0
Gallic acid,     -                0
Succinate and benzoate of am.    0*
  Concentrated sulphuric acid attacks maH- 
MAN
MAN
ganese, at the same time that hydrogen gas
is :Vsetigaged.  If sulphuric acid be added,
and diavvn off by distillation several times
from the black oxide, by a heat  nearly ap-
proaching to ignition, in a glass vessel, it is
found, that oxygen gas is  disengaged to-
ward the end of each process, and part of
the oxide is dissolved.   1 he solution ofthe
sulphate made from the metal  itself is co-
lourless,   if it be made from the black ox-
ide, it is a purplish-red; but this colour is de-
stroy ed by the light of the sun, and again re-
stored by removing the solution into the dark.
  Sulphurous acid dissolves the oxide, tak-
ing part of its oxygen, which converts it into
sul;>hurie acid, and thus forming a sulphate
with the remaining oxide.
  Nitric acid elissolves  manganese with ef-
fervescence, anel the escape of nitrous gas.
A spongy, black, and triable matter remains,
which is a  carburet of iron.  The  solution
dots not afford crystals.  The oxide is more
readily soluble in nitrous acid.
  Manganese is dissolved in the usual man-
ner by muriatic acid.  The solution of man-
ganese in  muriatic  acid  scarcely affords
crys ais: bit a deliquescent saline mass by
evaporation, which is soluble in alcohol.
  In ;he dry way, the oxide of manganese
combines with such earths  and saline sub-
stances as are capable of undergoing fusion
in a strong heat.   These experiments are
most  advantageously performed  by the
blow-pipe, winch see.
  This metal melts readily with most of the
other  metals, but rejects mercury.  Gold
and iron are rendered more fusible by a due
addition of manganese ; and the latter me-
tal is rendered  more ductile.  Copper be-
comes less fusible, and  is rendered whiter,
but of a colour subject to tarnish.
  The ore  of man canese, which is known in
Derbyshire by the name of black wadd, is
remarkable for its spontaneous inflammation
with oil.   It is of a dark brown colour, of a
friable earthy appearance, partly in powder,
and partly in lumps.  If half a pound of
this be dried before  a  fire, and afterward
suffered to cool for about an hour; and it
be then loosely mixed or kneaded with two
ounces of linseed oil;  the whole, in some-
thing more than half an hour, becomes gra-
dually hot, and at length bursts into flame.
This effect wants explanation.   It seems, in
some measure, to resemble the inflammation
of oils by the nitric acid.
  Manganese was used chiefly by  glass-
makers and potters;  but the important dis-
covery of chlorine has greatly  extended its
utility.  See Bleacrtng.*
  Mansa.   Several vegetables afford man-
na ; but the ash, the larch, and the alhagi,
afford it in the largest quantities.
  The ash which affords manna grows  na-
turally in all temperate climates; but Ca-
labria and Sicily appear ,o be the most na-
tural countries to this tree.
  The manna flows naturally from this tree,
and attaches itself to its sides in the form of
white transparent drops; but the extrac-
tion of this juice  is facilitated by incisions
made in the tree  during summer.
  Its  smell is strong, and its taste sweetish
and slightly  nauseous;  if exposed on hot
coals, it swells up, takes fire, and leaves a
light bulky coal.
  Water totally dissolves it, whether hot or
cold.  If it be boiled with lime, clarified with
white of egg, and concentrated by evapora-
tion, it affords crystals of sugar.
  Manna affords,  by distillation, water,acid,
oil, and ammonia; its coal aflbrds fixed al-
kali.
  This substance forms the basis ot many
purgative medicines.
  ' Man-ires. Animal and vegetable matters
introduced into the soil, to acceieiate vege-
tation, and increase the production ot crops.
They have been used since the earliest pe-
riods  of agriculture.  But  the manner in
which manures act, the best manner of ap-
plying them, and their relative value and
durability, were little understood, till the
great chemist who  gave new lustre to the
whole science, turned his mind  lo this, its
darkest, but most important application.   I
conceive it will be doing a service to society,
to aid the diffusion ot the light springing
from  the  invaluable researches  of Sir H.
Davy, by  inserting the following short ab-
stract from his Agricultural Chemistry.
  The pores in  the fibres of the roots of
plants are so small, that it is  with difficulty
they can be discovered by the microscope;
it is not therefore probable, that  solid sub-
stances can pass into them from the  sod. He
tried  an experiment on this  subject: some
impalpable powdered churcoal  procured by
washing gunpowder, and dissipating the sul-
phur by heat, was placed m a phial contain-
ing pure water, in which a plant of pepper-
mint was  growing; the roots  of the plant
were  pretty generally in contact with the
charcoal.  The experiment was made in the
beginning of May 1805 ;  the growth of the
plant was very vigorous during a fortnight,
when it  was taken out  of  the  phial -,m\e
roots  were cut through in different parts;
but no carbonaceous matter could be dis-
covered in them, nor were  the smallest fi-
brils  blackened by charcoal,  though this
must have been the case had the charcoal
been absorbed in  a solid form
  No substance is more necessary to plants
than carbonaceous  matter;  and  if this can-
not be introduced into the organs of plants
except in a state of solution,  there is every
reason to suppose, that other substances
less essential  will  be in the same  case.
  He found by some experiments made in
1804, that plants introduced into strong fresh
solutions of sugar, mucilage, tanning prin-
ciple, jelly, and other substances, died ,  but
:;..' plants lived in the same  solutions after 
MAN                                 MAN
they had fermented. At that time, he sup-
posed  that fermentation  was necessary to
prepare the food of  plants; but  he after-
wards found, that the deleterious  effect of
the recent vegetable solutions,  was owing
to their being too concentrated;  in conse-
quence of which the vegetable organs were
probably clogged with solid matter, and the
transpiration  by  the  leaves preventeel.  In
the beginning of June, in the next year, he
used solutions of the same substances,  but
so much diluted, that there was about only
one two-hundredth part of solid vegetable
or animal matter in the solutions.  Plants of
mint grew luxuriantly in all these solutions;
but least so in that of the astringent matter.
He watered some spots of grass in a garden
with the different solutions separately,  and
a spot with common water: the  grass wa-
tered  with solutions of  jelly, sugar,  and
mucilage, grew most vigorously;  and that
watered with the solution of the tanning
principle grew better than that watered with
common water.
   Vegetable and animal substances deposi-
ted in the  soil, as is shown by universal ex-
perience, are consumed during  the  process
of vegetation ;  and they can only nourish
the plant by affording solid matters capable
of being dissolved by water, or gaseous sub-
stances  capable of  being absorbed by the
fluids in the leaves of vegetables; but such
parts of them as are  rendered gaseous, and
 that pass into the atmosphere, must produce
 a comparatively small effect, for  gases soon
 become diffused through the  mass of the
 surrounding air. The great object in the ap-
 plication of  manure, should be  to make it
 afford as much soluble matter as possible to
 the roots of the plant;  and that in a slow
 and gradual manner, so that it may be en-
 tirely consumed in forming its sap and or-
 ganized parts.
   Whenever manures consist principally of
 matter soluble  in water, it is  evident that
 their fermentation or putrefaction should be
 prevented as much as possible; and the only
 cases in which  these processes can be use-
 ful, are when the manure consists principal-
 ly of vegetable or animal^re.  The circum-
 stances  necessary for the putrefaction of ani-
 mal substances, are similar to those required
 for the fermentation of  vegetable  substan-
 ces ; atemperature above the freezing point,
 the presence of water, and the presence of
 oxygen, at least in the first stage of the pro-
 cess.
   To prevent manures from decomposing,
 they  should be  preserved dry, defended
 from the contact of air, and kept as cool as
 possible.
    All gree7i succulent plants contain saccha-
 rine or mucilaginous matter,  with woody
 fibre, and readily ferment.   They cannot,
 therefore, if intended for manure, be used
  too soon after their death.
    Rape-cake, which is used with great suc-
cess as a manure, contains a large quantity
of mucilage, some albuminous matter, and a
small quantity of oil.   This manure should
be used recent, and kept as dry as possible
before it is  applied.   It forms an excellent
dressing for turnip crops;  and  is most eco-
nomically applied by being thrown into the
soil at the same time with the seed.  Who-
ever wishes to see this practice in  its high-
est degree  of perfection, should attend Mr.
Coke's annual sheep-shearing, at Holkham.
   Sea-weeds, consisting of different species
of fuci, algx,  and confervae, are  much used
as a manure on the sea coasts of Britain and
Ireland.    This manure is transient in its
effects, and does not last  tor  more than  a
single crop, which is easily accounted  for
from the large quantity of water, or the ele-
ments of water, it contains.  It decays with-
out producing heat when exposed to the at-
mosphere, and seems,  as  it were,  to melt
down and dissolve away. He has seen large
heaps entirely destroyed  in less  than two
years, nothing remaining  but a little black
fibrous matter.
   The best farmers in the west of England
use it as fresh as it can be procured; and
the practical results of this mode of apply-
ing it are exactly conformable to the theory
 of its operation.
   When straw  is made to ferment, it  be-
 comes a more manageable manure; but there
 is likewise, on the whole, a great loss of nu-
 tritive matter. More manure is perhaps sup-
 plied for a single crop ; but the land is  less
 improved  than it would be, supposing the
 whole of the  vegetable matter  could  be
 finely divided and mixed with the soil.
   Lord Meadowbank  states, that one part
 of dung is sufficient to bring three or four
 parts of peat into a state in which it is fitted
 to be applied  to land; but of course  the
 quantity must vary according to the nature
 ofthe dung and of the peat.   In cases in
 which some living  vegetables are mixed
 with the peat, the fermentation will be more
 readily effected
   Manures, from animal substances, in gen-
 eral, require no chemical  preparation to fit
 them for the soil.  The great  object of the
 farmer is to blend them with the earthy con-
 stituents in a proper  state of division, and
 to prevent their too rapid decomposition.
   Fish forms a  powerful manure, in what-
  ever state it is  applied ;  but it  cannot  be
  ploughed in too fresh, though the quantity
  should be limited.  Mr  Young records an
  experiment, in which  herrings spread over
  a field, and ploughed in for wheat, proeluced
  so rank a crop, that it was entirely laid be-
  fore harvest.
    Bones are much used as a manure in the
  neighbourhood  of  London.   After being
  broken, and boiled for grease, they are sold
  to the farmer.  The more divided they are,
  the  more powerful are their effects.  The
  expense of  grinding them in a mill would 
                MAN

probably be repaid by the increase of their
fertilizing powers ; and in the state of pow-
der they might be used in the  drill hus-
bandry, and delivered with the seed, in the
same manner as rape-cake.
   During the  putrefaction  of urine  the
greatest part of the soluble  animal matter
that it contains is destroyed • it should con-
sequently be used as fresh as possible ;  but
if not mixed with solid matter, it should be
diluted with water, as when pure it contains
too large a quantity of animal matter to form
a proper fluid  nourishment for absorption
by the roots of plants.
   Putrid urine abounds in ammoniacal salts ;
and though less active than fresh urine, is a
very powerful manure.
  Amongst excrementitioussolid substances
used as manures, one ofthe most  powerful
is the dung of birds that feed on animal food,
particularly  the dung of sea birds.   The
guano, which is used to a great  extent in
South America, and which is the manure
that fertilizes the sterile  plains of Peru, is a
production of this kind.
  It contains a fourth part of its weight of
uric acid, partly saturated with ammonia,
and partly wiih potash;  some  phosphoric
acid combined with ttie bases, and likewise
with lime.  Small quantities of sulphate and
muriate of potash, a little fatty matter,  and
some quartzose sanel.
  Night-soil, it is  well  known, is a very
powerful manure, and very liable to decom-
pose.
  The disagreeable smell of night-soil  may
be destroyed by mixing  it with quicklime;
and if exposed to  the atmosphere in  thin
layers strewed over with quicklime in fine
weather, it speedily  dries, is easily pulve-
rized, and in this state may be used in the
same  manner as rape-cake,  and delivered
into the furrow with the  seed.
  The Chinese, who have  more  practical
knowledge of the use  anel  application of
manures than  any  other  people  existing,
mix their  night-soil  with  one-third of its
weight of a fat marl, make it into cakes,
and dry it by exposure to the sun.  These
cakes, we are informed  by the French mis-
sionaries, have no  disagreeable smell,   and
form a common article of commerce of the
empire.
  After night-soil, pigeons'1 dung comes next
in order, as to fertilizing power.
  If the pure dung of cattle is to be used as
manure, like theother species of dung which
have been mentioned, there seems no reason
why it should be made to ferment except in
the soil; or if suffered to ferment,  it should
be only in a very slight degree. The grass
in the neighbourhood of  recently voided
dung',  is always coarse  and  dark green;
some  persons have  attributed this to a nox-
ious quality  in unfermenting  dung; but it
seems to be rather the result of an excess
of food furnished to the plants.
                 MAN

   A slight  incipient fermentation is un-
 doubtedly of use in the  dunghill; for by
 means of it a disposition  is brought on in
 the woody fibre to decav anel dissolve, when
 it is carried to the land, or ploughed  into
 the soil; and woody fibre is always in great
 excess in the refuse ofthe farm.
   Too great a degree of  fermentation is,
 however, very prejudicial to the composite
 manure in the dunghill;  it is  better  that
 there should be no   fermentation at all be-
 fore the manure is used, than that it should
 be carried too far.
   Within the last seven years, Mr. Coke lias
 entirely given up the system formerly adopt-
 ed on his farm, of applying fermented dung;
 and he  has founel, that his crops  have  been
 since as good as they ever were,  and that
 his manure goes nearly twice as far.
   In cases when farm-yard dung cannot be
 immediately applied to crops the destruc-
 tive fermentation of it should be prevewtea
 very carefully.
   The surface should be defended as much
 as possible from the oxygen of the atmos.
 phere ;  a compact marl, or a  tenacious
 clay, offers the best protection against the
 air ; and before the  dung  is  covered over,
,or, as it were,  sealed up,  it should be dried
 as much as possible.  If the dung is found
 at any time to heat strongly, it  should be
 turned over, and cooled by exposure to air.
   If a thermometer plunged into  the dung
 does not rise to above 100 degrees of Fahr.
 there is little danger of much a.'riform mat-
 ter flying oft".  If the temperature is higher,
 the  dung should  be  immediately spread
 abroad.
   When a piece of paper moistened in mu-
 riatic acid held over the steams arising from
 a dunghill gives dense fumes, it is a certain
 test that the decomposition is going too far,
 for this indicates that volatile alkali is dis-
 engaged.
   VV hen dung is to be preserved for any
 time, the situation in which it is kept  is of
 importance.   It should, if possible, be de-
 fended from the sun. To preserve it under
 sheds would be of great use; orto make the
 site of a dunghill on the north side of a wall.
   Soot, which is principally formed  from
 the combustion of pit-coal or coal, generally
 contains likewise substances derived  from
 animal  matters.   This is  a very powerful
 manure.
   It is well fitted to be used in the dry state,
 thrown into the ground with the seed, and
 requires no preparation. Lime should never
 be applied with animal manures, unless they
 are too rich, or for  the purpose of prevent-
 ing noxious effluvia.  It is injurious when
 mixed with any common dung, and tends t«
 render the extractive matter insoluble.
   "The doctrine of the proper application
 of manures from   organized  substances,"
 says this eloquent writer,  " otters an illus-
 tration of an important part ofthe economy 
MEA                                 MEL
©f nature, and of the happy order in which
it is arranged.
  " The death and decay  of animal sub-
stances tend to resolve organized forms into
chemical constituents;  and the pernicious
effluvia disengaged in the process, seem to
point out the propriety of burying them  in
the soil, where they are fitted to become
the food of vegatables.  The fermentation
and putrefaction of organized substances in
the free atmosphere, are noxious proces-
ses; beneath the surface ofthe ground they
are salutary operations.  In ihis  case, the
food  of plants is prepared where it can be
used ; and that which would offend the sen-
ses anel injure the health, if exposed,  is con-
verted by gradual processes into forms of
beauty and of usefulness ;  the fetid gas is
rendered a constituent ofthe aroma  of the
flower, and what might be poison, becomes
nourishment to animals and to man."*
  * Marble.  See Limesto.nk.*
  Mahcasite.  See Pr rites.
  Marl.  See Limestone.
  Marmor Metallicum. Native sulphate of
barytes.
  *Mars.   The mythological  and  alche-
mistical name of iron.*
  Mass.cot.  Yellow oxide of lead.  See Leas.
  Mastic.   A resinous substance  in the
form  of tears, of a  very pale yellow colour,
and farinaceous appearance,  having little
smell, and a bitter astringent taste. It flows
naturally from the tree, but its produce is
accelerated  by incisions.  The lesser tur-
pentine tree and  the  lentiscus afford the
mastic of commerce.
  No volatile oil is obtained from this sub-
stance when distilled with water.   Pure al-
cohol and oil of  turpentine  dissolve  it;
water scarcely  acts upon it;  though  by
mastication it becomes soft and tough, like
wax.    When chewed a little while,  howe-
ver, it is white, opaque, and brittle, so as not
to  be softened again by chewing.   The
part insoluble in alcohd much resembles in
its  properties caoutchouc.   It is used in
fumigations,  in the compositions of varnish-
es, and is supposed to strengthen  the gums.
  Matrass.   See  Laboratory.
  Matrix.   The  earthy or stony  matter
which accompanies ores, or envelopes them
in the earth.
  *Meadow-ore. Conchoidal Bog Iroit-ore.*
  Measures.   The  English  measures of
capacitvare according to the following table;
One gallon, wine mea- , four
  sure, is equal to   y     n-
One quart,      -     two pints.
One pint,    -    -    28.875 cubic inches.
  The pint is subdivided  by chemists and
apothecaries  into 16 ounces.
  The gallon, quart, and pint, ale measure,
are to the measures of the same denomina-
tions,  wine measure,  respectively, as 282 to
231.   See Acid (Muriatic).
  The Paris  foot is equal to 12.789 Eng-
lish inches, or to the English foot as 114 to
107. For measures of weight, see Balance.
  * Meerschaum.  Kettekil  of  Kirwan.
Colours, yellowish and grayish-white. Mas-
sive.  Dull.  Fracture fine earthy.   Frag-
ments angular.  Opaque.   Streak  slightly
shining. Does not soil.   Very soft, sectile,
but  rather difficultly frangible.  Adheres
strongly to the tongue. Feels rather greasy.
Sp. gr.  1.2 to 1.6.  Before the blow-pipe,
it melts on the edges into a white enamel.
Us constituents are,  silica 41.5, magnesia
13.25, lime 0.50, water and carbonic acid 39.
—Kiaproth. It occurs in the veins in the ser-
pent.ue of Cornwall.   When first dug, it is
soft, greasy, and lathers  like soap.   Hence
the Tartars use it for washing clothes,   lu
Turkey it is made into tobacco-pipes, from
meersclnum  dug in  Natolia, and near
Thebes.  See Jameson's mineralogy for an
entertaining account ofthe manufacture.*
   * Mi.ibni re. Prismato-pyramidal feldspar.
Colour, gr&yish-white.   Massive, but more
frequently crystallized.  The primitive form
is a pyramie,  in which the angles are 136°
22', 63° 22'.   Its secondary forms are, rec-
tangular foui-sided prisms, variously acumi-
nated or truncated.  The crystals are small,
smooth and  splendent.   Lustre  vitreous.
Cleavage,  doable rectangular. Transpa-
rent.  Harder  than  common feklspai-,  but
softer than quartz.  Easily frangible.  Sp.
gr. 2.6.  Easily fusible  before the  blow-
pipe, with intumescence.  It occurs along
with ceylanite and nepheline, in  granular
hmestone, at Monte Somma near Naples.*
   * Mklasite.  Colour, velvet-black.   In
roundish  grains, but more frequently crys-
tallized in a rhomboidal dodecahedron, trun-
cated on all the edges. Surface of the grains
rough and uneven; that ofthe crystals shin-
ing. Fracture flat conchoidal.  Opaque.  As
hard as quartz.  Rather  easily frangible.
Sp. gr. 3.73.  Its constituents are, silica 35 5,
alumina 6, lime  32.5, oxide of iron 25.25,
oxide  of  manganese 0.4, loss  0.35. It is
found in a rock at Frescati near Rome, and
in the basalt of Bohemia.*
   * Mellates.  Compounds of mellitic acid
with the salifiable bases.*
   *  Mellite,  or  Honey-stone.    Colour
honey-yellow.  Rarely massive. Crystalliz-
ed.  Its primitive figure  is  a pyramid of
118° 4/, and 93° 22'.  The secondary figures
are ; the primitive, truncated on the apices;
on the  apices and angles of the  common
base; and the angles on  the common base
bevelled.  Externally smooth and splendent.
Cleavage pyramidal.  Fracture perfect con-
choidal. Semi-transparent. Refractsdouble,
in the  direction  of  the pyramidal plane.
Harder than gypsum, but softer than cal-
careous spar.  Brittle.  Sp.gr. 1.4 to 1.6.
Before the blow pipe, it becomes white and
opaque, with black spots, and is at length
reduced to ashes; when heated in a close
vessel, it becomes black.  It is slightly roemo - 
MEll                                  MER
 electric  by friction.  Its  constituents are,
 alumina  16, mellitic acid 46,  water of crys-
 tallization 38.—Klaproth  It occurs super-
 imposed on bituminous wood, and earth coal,
 and is usually accompanied  with  sulphur.
 It has hitherto been found only at Artern in
 Thuringia.*
   *  Melting.   See  Caloric,  change  of
 state*
   * Mi-v^chakite.   Colour  grayish-black.
 Occurs only  in very small flattish  angular
 grains, which have a rough glimmering sur-
 face.   Glistening; adamantine, or semi-me-
 tallic lusire. Cleavage, imperfect.  Opaque,
 Not so hard as magnetic iron-sand.  Buttle.
 Retains  its  colour  in  the streak.   Sp. gr.
 4.3 to 4.4.  It is attractible by the  magnet,
 but in a much weaker degree, than magnetic
 iron-stone.  Infusible without addition.   It
 tinges borax of a greenish colour.  Its con-
 stituents are oxide of iron 51, oxide of tita-
 nium 45.25, oxide of manganese 0.25, silica
 3.5.—Klaproth.  It  is found, accompanied
 with fine quartz-sand, in the bed of a rivulet
 which  enters the  valley of iWanaccan in
 Cornwall.*
  * Menilite.  A sub-species jf indivisible
 quartz.  It is of two kinds;  tie brown and
the gray. Brown menilite is cAesnut-brown,
inclining to liver-brown. It o«curs tuberose.
 £ eternal surface, rough and dull;  internal
glistening.  It has sometimes a tendency to
lamellar distinct concretions. Fracture very
 flat conchoidal.  Translucent on the edges.
 Scratches tclass.   Easily frangible.   Sp.gr.
 2.17.   infusible.  Its constituents are, silica
 85.5, alumina 1, lime 0.5, oxide of iron 0.5,
 water  uid carbonaceous matter 11.0. Founel
 at Mend  Montant near  Paris, imbedded in
 adhesive slate, as flint is in chalk.
   Gray  Menilite.   Colour yellowish-gray.
 Tuberose.   Internally glimmering  or dull.
 Fracture as  above.   Semi-hard in  a high
 degree.  Easily frangible.  Sp. gr. 2.3.  It
 occurs at Argenteuil  near Paris, imbedded
 in a clayey marl.—Jameson.*
  * Mephitic Acid.   Carbonic Acin.*
   Menstruum.  A  word  synonymous with
 solvent.
   Mercury is distinguished from all  other
 metals by its extreme fusibility, which is
 such,  that it does not take the solid state
 until cooled to the thirty-ninth degree below
 0 on Fahrenheit's  thermometer;  and  of
 course it is always fluid in the temperate cli-
 mates  ofthe earth.  Its colour is white, and
 rather bitter than silver.  In the solid state
 it is malleable ;§ its specific gravity is 13.6.
 It is volatile, and rises in  small portions  at
 the common temperature ofthe atmosphere,
 as is evinced by several experiments, more
 especially in a vacuum, such as obtains in the
  § The reader will find an ample  account
of the freezing of quicksilver in Dr. Blag-
den's History, vol. lxxxiii. of the  Philoso-
phical Transactions.
 upper part  of a  barometer tube.  At the
 temperature of about 656-', it boils rapidly,
 and rises copiously in fumes.  When expos-
 ed to such a heat as may cause it  to rise
 quickly in the vaporous form, or about 600°,
 it gradually  becomes converted into  a red
 oxide, provided oxygen be present.  This
 was formerly known by  the  name  of pre-
 cipitate per  se.  A greater iieat, however,
 revives this  metallic oxide, at the same time
 that the oxygen  is again extricated.  Ten
 days or a fortnight's constantheai is required
 to convert a few grains of mercury into pre-
 cipitate per  se in the  small way.
   From this volatility of mercury, it is com-
 monly purified by distillation.
   Mercury  is not perceptibly altered by
 mere  exposure to the air; though by long
 agitation,  with access of air, it becomes con-
 verted into a black powder or oxide, which
 gives  out oxygen  by  heat, the metal being
 at the same time revived.
  * When calomel or protochloride of mer-
 cury is acted on by potash-water, it yields
the pure black protoxide; and when corro-
sive sublimate or the deutochloride is treated
in the same way, it affords the reddeutoxide.
The former oxide, heated with access of air,
slowly changes into the latter.   The consti-
tuents ofthe first are 100 metal -|-  4 oxy-
gen ;  of the  second 100 + 8.  Hence the
prime equivalent  of  mercury is 25.   At a
red heat both oxides emit their oxygen, and
pass to the metallic state.  A moderate heat
converts the black oxide, partly into running
mercury, and partly  into red oxide.  The
deutoxide, as usually prepared from the ni-
trate by gentle calcination, is  in brilliant
red scales, which become of an orange hue
 when  finely comminuted.  It  frequently
 contains a little undecomposed subnitrate.
  By triturating mercurj  with unctuous or
 viscid matters, it is changed partly into pro-
 toxide, and partly  into very minute globules.
 By exposing mercurial ointment to a mode-
 rate heat, the globules fall down, while a
 proportion of the oxide remains combined
 with the grease.  This light gray chemical
 compound is supposed to possess all the vir-
 tues of the dark coloured ointment, and to
 be cheaper and more convenient in the ap-
 plication.  Mr. Donovan, who introduced it,
 forms it directly by exposing a mixture of 1
 part of black oxide,  and 24 parts of hogs'
 lard, to a heat of 350", for about two hours.
   Red oxide of mercury is acrid and poison-
 ous, and carries these qualities into its saline
 combinations. The protoxide is relatively
 bland, and is the basis of all the mild mercu-
 rial meuicines.
  1. When  mercury is heated in chlorine, it
 burns with a pale red flame, and the sub-
 stance called corrosive sublimate is formed.
 This  deutochloride may also be formed by
 mixing together equal parts of dry bi-deuto-
 sulphate of mercury and common salt, and
 subliming.  The corrosive sublimate  rises, 
MER
MER
 and incrusts the top  of the  vessel, in the
 form of a beautiful white semi-transparent
 mass, composed of very small  prismatic
 needles.  It may be obtained in cubes, and
 rhomboidal prisms, or quadrangular prisms,
 with their sides alternately  narrower, and
 terminated by dihedral summits.  Its sp. gr.
 is 5.14.  Its taste  is acrid, stypto-metallic,
 and eminently disagreeable.   It is a deadly
 poison. Twenty parts of cold water dissolve
 it, and less than one of boiling water.  luO
 parts of alcohol at the boiling temperature
 dissolve 88 of corrosive sublimate ; and at
 70° they dissolve 37.5 parts.   The constitu-
 ents of this chloride are,—
     Mercurv,  25              73.53
     Chlorine,   9              26.47
   It may  be recognized by  the following
 characters: It volatilizes  in  white  fumes,
 which seem to tarnish a bright copperplate,
 but really communicate a coating of metal-
 lic mercury, which appears glossy white on
 friction.  When caustic potash is  made to
 act on it, with heat, in a glass tube, a red
 colour appears, which by gentle ignition va-
 nishes, and metallic mercury is then found
 to line the upper  part ofthe  tube in minute
 globules.   Solution of corrosive sublimate
 reddens litmus paper; but changes sirup of
 violets to  green. Bicarbonate  of potash
 throws down  from  it  a deep  brick-red
 precipitate,  from which  metalhc mercury
 may be procured  by  heating it in a tube.
 Caustic potash gives a yellow precipitate ;
 but if the solution be very dilute, a white
 cloud only  is  occasioned, which becomes
 yellowish-red  on  subsidence.  Lime-water
 causes a deep yellow, verging on red.  Wa-
 ter of ammonia forms a  white precipitate,
 which becomes yellow  on  being  heated.
 With sulphuretted hydrogen and hydrosul-
 phurets, a black or blackish-brown  precipi-
 tate appears.  Nitrate of silver throws down
 the curdy precipitate characteristic of mu-
 riatic acid; and the protomuriate of tin gives
 a white precipitate. The proper antidote to
 the poison of corrosive  sublimate, is the
 white of egg or albumen, which converts it
 into calomel. Sulphuretted hydrogen water
 may also be employed, along with emetics.
 From  six  to twelve grains were the mortal
 doses employed by Orfilain his experiments
 on dogs.  They died in horrible convulsions
 generally in two hours. But when,  with the
 larger quantity, the whites  of eight eggs
 were thrown into  the stomach, the animals
 soon recovered, after vomiting.   Corrosive
 sublimate, digested with albumen for some
 time, was given in considerable doses, with
 impunity.   The instructions  given under
 arsenic, for examination of the bowels of a
 person supposed to be poisoned, are equally
 applicable to poisoning by corrosive subli-
 mate ; and the appearances are much the
 same.
  2. Protochloride  of mercury,  mercurius
tltdci?, or calomel, is usually formed from the
deutochloride, by triturating four parts of
the latter with three of quicksilver, till the
globules disappear,  and subjecting tiie mix-
ture to a subliming heat.  By levigating and
edulcorating with v arm water the sublimed
grayish-white cake, the portion of soluble
corrosive sublimate which had escaped de-
composition  is removed.  It may also be
made by adding solution  of protonitrate of
mercurv to solution of common  salt.   The
protochloride or calomel precipitates.   The
following is the process used at Apotheca-
ries' Hall, London; 50 lbs. of mercurv are
boiled with 70 lbs. of sulphuric acid, to dry-
ness, in a cast-iron vessel; 62 lbs. of the dry
salt are triturated with 40$ lbs. of mercury,
until the globules disappear, and 34 lbs. of
common salt are then added. This mixture
is submitted to heat in earthen vessels, and
from 95 to 100 lbs.  of calomel are the re-
sult.  It is washed in large quantities of dis-
tilled water, after having been ground to a
fine and impalpable powder.
   When protochloride of mercury is very
slowly resublimed, four-sided prisms, termi-
nated by pyramids,  are obtained. It is  near-
ly tasteless and insoluble,  and is purgative in
doses of five or  six grains.  Its sp. gr. is
7.176.   Exposure to air darkens its surface.
When two pieces are rubbed in the dark,
they phosphoresce.  It is not so volatile as
the  deutochloride.    Nitric acid dissolves
calomel, converting it into corrosive subli-
mate.  Protochloride of mercury is  com-
posed of
     Mercury,   25.           84.746
    Chlorine,    4.5           15.254
   We have aiso two sulphurets of mercury;
the black or ethiops mineral; and the red or
cinnabar.
   The first is easily  made by heating or tri*
turating the ingredients together, or by add-
ing a hydrosulphuret of alkali to a mercu-
rial saline solution.   It consists of
     Mercury,   25              92.6
     Sulphur,     2                7.4
   When the black  sulphuret is exposed to
a  red heat in earthen pots, cinnabar sub-
limes,  which, when reduced to powder, is
of a beautiful red colour, and is used as a
pigment under the  name  of  vermilion.  Its
sp. gr. is about 10.  It is  insoluble, insipid,
and burns with a blue flame.  If it be mixed
with half its weight  of iron filings, and dis-
tilled in a retort, it yields  pure mercury. It
is deutosulphuret, and consists of
    Mercury,   25               86.2
    Sulphur,     4               13.8
   The salts of mercury have the following
general characters.-—
  1.  A dull red heat volatilizes them.
  2.  Ferroprussiate  of potash gives a white
precipitate.
  3.  Hydrosulphuret, black.
  4.  Muriate of soda, with the  protosalts,
white.
  5,  Gallic acid, orange-yellow. 
MER                                  ME II
   6. Plate of copper, quicksilver.*
   The sulphuric acid does not act on this
metal, unless it be well  concentrated and
boiling. For this purpose  mercury is poured
into a glass  retort,  with nearly  twice its
weight of sulphuric acid. As soon as the
mixture is heated, a strong  effervescence
takes place,  sulphurous  acid gas escapes,
the surface of the mercury becomes white,
and a white powder is produced  when the
gas ceases to come  over, the mercury  is
round to be converted into a white, opaque,
eaustic, saline mass, at the bottom ofthe re-
tort, which weighs one-third  more than the
mercury,  and is d composed by heat.  Its
fixity is considerably greater than that  of
mercury  itself.   If the heat be  raised,  it
gi\ es out  a considerable  quantity of oxy-
gen, the  mercury being at the same time
revived.
   Water resolves it into  two salts, the bi-
sulphare and subsnlphate ; the latter is of a
yellow colour.  Much  washing is required
to produce this colour,  if cold  water be
used; but if a large quantity of hot water be
poured on, it immedirJely assumes a bright
lemon colour.  In this state  it is called tur-
peth mineral.   The other affords, by evapo-
ration, small, needK-. deliquescent en stals.
   The fixed alkalis, magnesia, and lime pre-
cipitate oxide of mercurv  from its solutions ;
these precipitates are reducible  in closed
vessels by mere  heat without addition.
   The nitric acid rapidly attacks and dis-
solves mercury, at the same time that a large
quantity of nitrous gas is disengaged ; and
the colour of the acid becomes green during
its escape.  Strong nitric acid takes up its
own weight  of mercury in  the cold; and
this solution will  bear to be diluted with
water.  But  if the solution  be made with
the assistance of heat, a  much larger quan-
tity  is dissolved ; and  a  precipitate will be
afforded by the addition  of distilled water,
which is of a yellow colour if the water be
hot. or white if it be cold; and greatly re-
sembles the turpeth  mineral produceel with
sulphuric acid; it has accordingly been cal-
led nitrous turpeth.
   All the combinations of mercury and ni-
tric acid are very caustic, and form a deep
purple or black spot upon the skin.  They
afford crystals, which differ according to the
state ofthe solution.  When  nitric acid has
taken up as much mercury as it can dissolve
by heat,  it usually assumes  the form of a
white saline mass.  When the combination
of nitric acid and mercury is  exposed to  a
gradual and long continued low heat, it gives
out a portion of nitric.acid,  and becomes
converted into a bright red oxide, still re-
taining a  small portion  of acid.  This  is
known by the name of red precipitate, and
is much used as an escharotic.
  When red precipitate is strongly heated,
a large quantity  of oxygen is disengag-
ed, together  with some  nitrogen, and the
mercury is sublimed in the metallic form.
  Nitrate of mercury is more soluble in hot
than cold water, and affords crystals by cool-
ing.   It is decomposed by the affusion of a
large quantity of water, unless the acid be
in excess.
  A fulminating preparation of mercury was
discovered by  Mr.  Howard. A hundred
grains  of mercury are to be dissolved by
heat in an ounce and half by measure of ni-
tric acid.  This solution being poured cold
into two ounces by measure of alcohol in a
glass vessel, heat is to be.applied, till eller-
vescence is excited.  A white vapour undu-
lates on the surface, and a powder is gradu-
ally precipitated, which is immediately to
be collected on  a filter, well washed,"and
cautiously dried with a very moderate heat.
This powder, detonates loudly  by  gentie
heat, or slight friction.
  The acetic and most other acids combine
with the oxide of mercury, and precipitate
it from its solution in the nitric acid.
  When one part of native sulphuret of an-
timony is triturated or accurately mixed with
two parts of corrosive sublimate,and exposed
to distillation; the chlorine  combines  with
the antimony, and rises in the form of the
compound called butter of antimony, while
the sulphur combines  with  the  mercury,
and forms cinnabar.  If antimony be used
instead ofthe sulphuret, the residue which
rises last consists  of running mercury, in-
stead of cinnabar.
  Mercury,  being habituallv fluid, very rea-
dily combines with  most of the  metals, to
which it communicates more or  less of its
fusibility.  When  these metallic mixtures
contain a sufficient quantity of mercury to
render them soft  at a mean temperature,
they are called amalgams.
  It very readily  combines with gold, sil-
ver, lead, tin, bismuth, and zinc; more dif-
ficultly with copper, arsenic, and  antimony;
and scarcely at all with platina  or iron: it
does not unite with nickel, manganese, or
cobalt;  and its action on tungsten and
molybdena is not known.  Looking-glasses
are cove red on  the  back surface with an
amalgam of tin.   See Silvering.
  Some of the uses of mercury have alrea-
dy been mentioned in  the present article.
The amalgamation of the  noble metals,
water-gilding, the making of vermilion, the
silvering of looking-glasses,  the  making of
barometers and thei-mometers, and the pre-
paration of several powerful medicines, are
the principal uses to  which this metal is
applied.
  Scarcely any  substance  is so liable to
adulteration as mercurv, owing to the  pro-
perty which it possesses of dissolving com-
pletely  some of the  baser metals.  This
union is so strong, that they even rise along
with the quicksilver  when  distilled.  The
impurity of mercury is generally  indicated
by its dull aspect; by ite tarnishing, and be- 
MER                                 MET
 coming covered with a  coat  of oxide, on
 long exposure to the air; by its adhesion to
 the surface of glass;  and, when shaken
 with water in a bottle, by  the speedy for-
 mation of a black powder.  Lead and tin
 are frequent  impurities, and the mercury
 becomes  capable  of taking  up  more  of
 these, if zinc  or bismuth be previously ad-
 ded. In order to discover lead, the mercury
 may be agitated with a little water, in order
 to oxidize that metal.   Pour off the water,
 and digest the mercury with a little acetic
 acid.  This will dissolve the oxide of lead,
 which will be indicated by  a blackish  pre-
 cipitate with  sulphuretted water.  Or to
 this acetic solution add a little  sulphate of
 soda,  which  will precipitate  a  sulphate of
 lead,  containing, when dry, 72  per cent of
 metal.  If only a  very  minute quantity of
 lead be present in a large quantity of mer-
 cury, it may be detected by solution in ni-
 tricacid, and  the  addition  of sulphuretted
 water.  A dark brown precipitate will ensue,
 and will subside if allowed to stand a few
 days.'  One part oflead may thus be sepa-
 rated from 15263 parts  of  mercury.  Bis-
 muth is detected by pouring  a  nitric solu-
 «" in, prepared without heat, into distilled
  ater; a white  precipitate  will appear if
 this metal be  present.   Tin is manifested,
 in like manner, by a weak solution of nitro-
 muriate of gold,  which throws down a  pur-
 ple  sediment; and  zinc by exposing the
 metal to heat.
   The black oxide is rarely  adulterated ; as
 it  would be  difficult  to find a substance
 well suited to this purpose.  If well pre-
 pared, it may  be totally volatilized by heat.
  The red oxide of mercury  by nitric acid is
 very liable  to adulteration with red lead.
 It should be totally volatilized by heat.
  Red sulphuret  of mercury is  frequently
 adulterated with  red lead; which may be
 detected by heat.
   Corrosive muriate of mercury.  If there be
 any reason to  suspect  arsenic in this  salt,
 the  fraud may  be  discovered  as follows:
 Dissolve a small quantity of the  sublimate
 in distilled water;  add a solution of carbo-
 nate of ammonia till the precipitation ceas-
 es, and filter the  solution.   If, on the addi-
 tion of a  few  drops of ammoniated copper
 to this solution, a precipitate of a yellowish-
 green colour be  produced, the  sublimate
 contains arsenic.                    •
  Sub-muriate  of  mercury,  or  calomel,
 should be completely saturated with mer-
 cury.  This may be ascertained  by boiling,
 for a few minutes, one part of calomel with
 a thirty-second part of  muriate of ammonia
in ten parts of distilled water.   When car-
 bonate of potash is added to the filtered so-
 lution,  no precipitation  will ensue, if the
 calomel be pure.  This preparation, when
rubbed in an earthen mortar with pure am-
monia, should  become intensely black, and
should exhibit nothing of an orange hue.
  Vol. II.
  * Mesotypi!.   Prismatic zeolite.   Thil
species ot the genus zeolite, is divided by
Professor Jameson into three  sub-species,
the fibrous zeolite, natrolite,and mealy zeo-
lite; which see *
  * Meta s., The most numerous class of
undecoinpounded chemical bodies,  distin-
guished by  the following general charac-
ters : —
   I. They possess a peculiar lustre, which
continues in the streak, and in their smal-
lest fragments.
  2 They are fusible by heat; and in  fu-
sion retain the.r lustre and opacity.
  3. They are  all, except  selenium, excel-
lent conductors both of electricity and calo-
ric.
  4. Many of them may be extended under
the hammer, and are  called malleable;  or
under the rolling press, and are called lamin-
able; or  drawn into  wire, and are called
ductile.   This  capability  of extention, de-
pends in some measure on a tenacitjupecu-
liar to the metals, and which  exists in  the
different  specfes with very  different  de-
grees of force. See Cohesion.
  5. When  their saline combinations  are
electrized, the metals separate at the resino-
electric or negative pole.
  6. When  exposed  to the action of oxy-
gen, chlorine, or iodine, at an elevated tem-
perature, they  generally  take fire, and,
combining with  one or   other  of  these
three elementary dissolvents in  definite
proportions,  are  converted into earthy or
saline  looking bodies, devoid of metallic
lustre and ductility, called oxides, chlorides,
or iodides.
  7. They arecapab^e of combining in their
melted  slate with  each  qther, in  almost
every proportion, cons'"tuting the impor-
tant order of metallic alloys; in which  the
characteris'ic lustre and tenacity  are pre-
serve'.1,   feee Allot.
  8. From this brilliancy and  opacity con-
jointly, they reflect the greater part ofthe
light which falls on their surface, and hence
form excellent mirrors.
  9. Most of them combine in definite pro-
portions  with  sulphur and  phosphorus,
forming bodies frequently of a semi-metallic
aspect; and others unite  with hydrogen,
carbon and  boron, giving rise to peculiar
gaseous or solid compounds.
  10.  Many of the metals are capable of as-
suming, by particular management, crystal-
line forms;  which are, for the most part,
either cubes or octahedrons.
  The relations ofthe  metals to the various
objects  of chemistry,  are  so  complex and
diversified, as to render  their  classification
a task of peculiar difficulty. I have not seen
any arrangement  to  which  important  ob-
jections may not be offered; nor do 1 hope
to present one which shall be exempt from
crrdUsm.  The main purposes of a methodi-
cal distribution are to facilitate the acquire-
                 23 
MET
MET
fflent, retention, and application of know-
ledge.  With regard to metals  in general,
I conceive these purposes may be to a con-
siderable extent attained, by beginning with
those which  are most  eminently endowed
with the  charaders of the genus, which
most  distinctly possess the properties that
constitute their  value  in common life, and
which caused the early inhabitants of the
earth to give to the  first metallurgists a
place in  mythology.   Happy had their
idolatry been always confined to such real
benefactors!
 Inventas aut qui vitam  excoluere per artes;
 Quique sui memores, aliosfecere merendo.
  By arranging metals  according to the de-
gree  in  which they possess the obvious
qualities  of  unalterability by  common
agents, tenarity and lustre, we also concili-
ate their most important chemical relations,
namely, those to oxygen,  chlorine and io-
dine; since their metallic pre-eminence is,
popularly speaking, inversely as their affi-
                          ■  General Table
nities for these dissolvents.  In a strictly
scientific view, their habitudes with oxy gen*
should  perhaps be less regarded in their
classification, than  with chlorine ; for this
element has the most energetic attraction*
for the metals. But, on the other hand, oxy-
gen,  which forms one-fifth of the atmos-
pheric  volume, and  eight-ninths of  the
aqueous mass, operates to a much greater
extent  among  metallic bodies, and  inces-
santly modifies their form, both  in nature
and art.  Now the order we propose  to fol-
low will indicate very nearly their relations
to oxygen.  As we  progressively descend,
the influence of that beautiful element pro>
gressively  increases.   Among the  bodies
near the head, its powers are subjugated by
the metallic constitution;  but among those
near the bottom, it exercises an almost des-
potic sway,  which Volta's magical pile, di-
rected by the genius of Davy, can only sus-
pend for a season. The emancipated metal
soon relapses under thedominion of oxygen.
of the Metals.
NAMES.	Sp. Gr.	Precipitants.		Colour of precipitates by		
			Ferroprussiate of potash.	Infus. of gaits.	Hydrosul-phuiets.	Sulphuretted hydrogen.
1 Platinum	2(47	Mur. ammon.	0	0-		Black met-pow.
2 Gold	19.30	C Sulph. iron \ Nitr.int-rcury	Yellowish white	Green; met.	Yellow	Yellow
3 Silver	10.45	Common salt	White	Yel.-brown	Black	Black
4 Palladium	11.8	Prus. mercury	Deep orange		Blackish brown	Black-brown
i Mercury	13.6	I Common Salt 1 Heat	White passing to yellow	Orange-yellow	Brownish-black	Black
6 Copper	8.9	Iron	Red-brown	Brown	Black	Do.
7 Iron	7.T	C Succin. soda \ with perox.	Blue, or white passing to blue	Protox. 0 Perox. black	Black	0
8 Tin	7.29	Corr. sublim.	White	0	C Protox. black I Perox. yellow Black '	Brown
9 Lead	11.35	Suiph. soda	Do.	White		Black
10 Nickel	8>4	Sulph. potash?	Do.	Gray-white	Do.	0
11 Cadmium	8.6	Zinc	Do.	0	Orange-yellow	Jrange-vellow fellowith-white
12 Zinc	6.9	A Ik. carbon.	Do.	O	White	
13 Bismuth	9.83	Water	Do.	Yellow	Black-brown	Black-brown
14 Antimony	6.70	C Water I Zinc	With dilute so-lutions white	White from wa-ter	Orange	Orange
M Manganese	8.	Tartr. Dot.	White	O	White	Milkiness
16 Cooalt	8.6 \ik carbon.		Brown-yellow	Yellow-white	Black	0
17 Tellurium	6.115 J Water		0	Yellow	Blackish	
		(. Antimony				
18 Arsenic	C8-35? 15.76 ?	Nitr. lead	White		Yellow	Yellow
1° Chromium	5.90	Do.	Green	Brown	Green	
20 Molybdenum	8.6	I>0. ?	Brown	Deep brown		Brown
21 Tungsten	17.4	Mur. lime?	Dilute acids			
22 Columbium	5.6?	Zinc or inf. gal	Olive	Orange	Chocolate	
23 Selenium	4.3?	5 Iron { Sulphite am.				
						
34 Osmium	?	Mercury		Purple passing to deep blue		
25 Rhodium	10.65	Zinc?	O		0	
26 Iridium	18.68	Do.?	0	0		
27 Uranium	9.0	Ferropr. pot.	Brown-red	Chocolate	Brown-yellow	0
28 Titanium	?	Inf. galls	Grass-green	Red-brown	Grass-green	O
29 Cerium	?	Oxal. amm.	Milk-white	0	White	0
3o Wodanium	11.47	Zinc	Pearl gray	0		
31 Potassium	0.865	C Mur. plat. £ Tart, acid	0	0	0	0
32 Sodium	0.972					
33 Lithium						
34 Calcium						
3* Barium						
36 Strontium						
37 Magnesium						
18 Yttrium						
39 Glucinum						
40 Aluminum						
41 Thorinum						
42 Zirconium			•			
43 Silicium	——,-	-_«______.		■■ .		-.
 
MET                                MET
  ^The first 12 are malleable; and so are ttie
olst, 32d, and 33d in their congealed state.
  The first 16 yield oxides, which are neu-
tral salifiable  bases.
  The metals 17, 18, 19, 20, 21, 22, and 23,
are acidifiable by combination with oxygen.
Ofthe oxides of the rest, up to  the 31st,
little is known.  The remaining metals form,
with oxygen, the alkaline and earthy bases.
  The order of their affinity for oxygen, as
far asit has been ascertained, is stated in the
table of Elective Attraction of oxygen
and the metals.
  We shall  now give an example of the
method of analyzing a metallic alloy, of sil-
ver, copper, lead, bismuth, and tin.
   Let it be dissolved, with the aid of heat,
in  an excess of nitric  acid, sp.  gr. 1.23-
Evaporate the  solution almost to dryness,
and pour water on the residuum. We shall
thus obtain a solution of the nitrates of sil-
ver, copper, and lead, while the oxides of
tin and bismuth will be left at the bottom.
By exposing the latter mixture, to the ac-
tion of nitric acid, the oxide of bismuth will
 be separated from that of tin.   To deter-
mine  the proportions of the Either metals,
we pour first into the hot and pretty dilute
solution, muriatic acid,  which  will  throw
down the  silver.  After filtration, we add
sulphate of soda, to separate the lead ; and
finally, carbonate of potash to precipitate
 the zinc.  The quantity of each  metal, may
 now be deduced from  the  weight of each
 precipitate,  according to its specific nature,
 agreeably to the prindples of composition,
 given under the individual metals.  See
 Okes (Analysis of).*
   * Meteoholites, or Mf.tkortc Stones, are
 peculiar solid compounds of earthy and me-
 tallic matters, of singular aspect and com-
 position, which occasionally descend from
 the atmosphere, usually from the bosom of
 a luminous meteor.  This phenomenon af-
 fords an instructive example of the triumph
 of  human  testimony,  over philosophical
 scepticism.  The chronicles of almost every
 age  had  recorded the fall of ponderous
 stony or earthy masses from the air;  but the
 evidence  had  been rejected by  historians,
 forsooth, because the phenomenon was not
 within  the  range of their philosophy.  At
 length 4 the  sober and solid researches of
  ?>hysical science^put to shame theincredu-
  ity ofthe metaphysical school.
    " While all  Europe," says the celebrated
 Vauquelin, "resounded with the rumour of
 stones  fallen from the heavens,  and while
 philosophers,   distracted  in opinion, were
 framing hypotheses to explain their origin,
 each according to his own fancy, the Hon.
  Mr. Howard, an able English chemist, was
 pursuing in silence  the only route which
  eould lead to a solution ofthe problem. He
 collected specimens  of stone*  which had
 fallen at different times, procured as much
information as possible respecting  them,
compared the physical or exterior charac-
ters  of these bodies; and even did more,
in subjecting them to chemical analysis, by
means as ingenious as exact.
   " It results from hi9  researches,  that the
stones which fell in England, in  Italy, in
Germany, in the East Indies, and in other
places, have all such a  perfect resemblance,
that it »is  almost impossible  to distinguish
them from each other; and what renders
the similitude more perfect and more strik-
ing is, that they  are composed of the same
principles, and nearly  in' the same propor-
tions."
   I have given this just and handsome tri-
bute to English genius in the form of a quo-
tation from the French chemist; by appro-
priating the language to one's self,  as has
been practised in a recent compilation, the
force ofthe compliment is in a great mea-
sure done away.
   "  I should have abstained," continues M.
Vauquelin, " from any public notice of an
object, which has been treated of in so able
a manner by the English chemist, if he him-
self had not induced me to  do so,  during
his residence in  Paris;  had  not the stones
which I analyzed been from another coun-
try ; and  had not the interest excited by
the  subject, rendered this repetition excu-
sable.
   " It is therefore to  gratify Mr. Howard;
to give, if possible, more weight to  his ex-
 periments ; and  to enable  philosophers to
place full confidence in them, father than
to offer any thing new, that I publish this
memoir." Journal des  Mines, No. 76;  and
 Tilloch's .1/iff. vol. xv. p. 346.
   It is remaRcable, that all the stones, at
 whatever period, or in whatever part ofthe
 world, they may have  fallen, have appeared,
 as far as they have been examined,  to con-
sist of the  same  substances; and to  have
 nothing similar to them, not only among the
 minerals in the neighbourhood ofthe places
 where they were found, but among all that
 have hitherto been discovered in our earth,
 as far as men have been able to penetrate.
 For the chemical analysis of a considerable
 number of specimens  we are particularly
 indebted to Mr. Howard, as well as to Klap-
 roth and Vauquelin, and a precise mineralo-
 gical description of them has been given by
 the Count de Bournon and others.
   They are all covered with a thin crust of
  a deep black colour; they are without gloss,
  and their surface  is roughened  with small
  asperities.  Internally they are grayish, and*
  of a gi^nulatefl texture, more or less fine.
  Four different substances are interspersed
  among their texture,  easily distinguished by
  a lens. The most abundanllis from the size
  of a pin's head  to that of  a  pea, opaque,
  with a little lustre like that  of enamel, of a
  gray colour sometimes inclined to brown, 
MET                                 MET
   and hard enough to give faint sparks with
   steel.   Another is a martial  pyrites, of a
   reddish-yellow colour, black when powder-
   ed, not very firm in its texture, and nor. at-
   tractive by the magnet.  A third consists
   of small particles of iron in a perfectly me-
   tallic state, which g"ive to the mass the qual-
   ity of being attracted by the magnet, though
   in some specimens they do not exceed  wo
   per cent of the whole  weight  wMule in
   others they extend to a.fourth.  These are
   connected together by a fourth of an earthy
   consistence in most, so that  they may be
   broken to  pieces by the fingers with more
   or less  difficulty.  The black  crusi is hard
   enough to emit sparks with steel, but may
   be broken by a stroke with a hninindt>, and
   appears to  possess  the  properties of the
   very attractive black oxide of iron.   Their
   specific gravity varies from  3.352 to 4.281
     The  crust appears to contain nickel uni-
   ted with iron, but" Mr. Hatchett could not
   determine its  proportion.  The pyrites he
   estimates at  iron  .68, sulphur .13, nickel
   .06, extraneous earthy, matter .13.  In the
   metallic particles disseminated tlirough the
   mass, the  nickel  was in the proportion of
   one part, or thereabout,  to  three of iron.
   The hard separate bodies gave  silex  .50,
   magnesia .15, oxide of iron  .34, oxide of
   nickel  .025;  and  the  cement, or matrix,
   silex .48, magnesia .18, oxide of iron  .34,
   oxide  of nickel .025.   The. increase  of
   weight in both these arose from the higher
   oxidation of  the iron.  These proportions
   are taken'from the stones that fell at Bena-
   res on the 19th of December 1798.
     The soli ary masses of native  iron, that
   have been found in Siberia, Jtohehiia, Sene-
   gal, and South America, likewise agree in
   the  circumstance of  being an alloy of iron
   and nickel; and are either of a cellular tex-
   ture, or  have  earthy matter disseminated
   among  the metal.  Hence, a similar origin
   has been ascribed to them.
     Laugier, and afterward Thenard,  found
   chrome likewise, in the proportion of about
   one per cent, in different  meteoric stones
   they examined.
     In all the instances in which these stones
   have been supposed  to fall from the clouds,
 •  and of which  any perfect account has been
   given, the appearance of a luminous meteor,
   exploding with loud  noise, has immediately
  .preceded, and hence has been looked to as
   the  cause.  The stones likewise have been
   more or less hot,  when found irnmedia.ely
   after their supposed fall.  Different opinions
•  however have been entertained on this sub-
  ject, which  is certainly involved -in much
   difficulty.  Some have supposed them to be
   merely projected from  volcanoes;  while
   others have slggested, that they  might be
   thrown from the moon ;  or be bodies wan-
   dering through space, and at length brought
   within the sphere of attraction ofourplanet.
   Various  lists of the periods, places, and
appearances of these showers of stony and
earthy matters, have been given from tune
to time in the scientific Journals.  1 he  la-
test and most complete is that published in
the 1st vol. ofthe Ed. Phil. Journ. compiled
partly f'r.im a  printed list by Cnladm, and
partly from a  manuscript one of Air. Allan,
read  some years ago, at  the Royal society
of Edinburgh.  It  appears tha. Doinemco
Troth,  a  Jesuit, published at AloUena, in
1766, a work  entitled, Deda  Caduta di  un
Sasso dull Aria, ragionamento,  in whicli the
ingenious author proves, in the clearest man-
ner, both from ancient and modern history,
that stones had repeatedly  fallen from the
heavens.  This curious dissertation (ragiuna-
mento) is in the possession of Mr. Allan.  The
compiler of the new hsi. justly observes, that
nothing can show  more  strikingly the uni-
versality and obstinacy of  that scepacism,
which discredits every thing that it cannot
understand, than the circumstance that his
work should have produced so little effect,
and that,  the numerous falls of meteoric
stones should have so long been  ranked
among the mventions of ignorant credulity.
   Mr. Howard's admirable  dissertation was
published in  the Phil. Trans, for 1802.  It
is reprinted in the 13th vol. ot Tilloch's
Magazine, and ought to be studied as a pat-
tern of scientific research.   The following
.Table is copied from the above Journal :—

Chuoxoiogical List of  Meteoric Stones.
     Sect. 1.—Before the Christian Era.
Division I.—Containing those which can be
     referred pretty nearly to a date.
A. C.
1478.  The thunderstone  in  Crete,  men-
   tioned  by Malchus, and regarded proba-
   bly as the symbol of Cybele.— Chronicle
   ofParos, 1.  18, 19.
1431.  Shower of Stones which destroyed
   the enemies of Joshua afT Beth-horon.—
   Joshua, chap. x. 11
12^)0.  Stones preserved at Orchomenos.—
   Pausanias.
1168.  A mass of iron upon Mount Ida in
   Crete.— Chronicle of Paros, J. 22.
705 or 7u4.   The Ai/cyle or sacred shield,
   which fell in the  reign of Numa.  It had
   nearly the same shape as those which itII
   at the Cape and at Agram.  Plutarch, in
   Num.
654.  Stones which fell  upon Mount Alba,
   in the reign of Tullus Hostilius.—" Crebri
   cecidere coelo lapides."— Liv.  1. 31.
644.   Five stones  which fell in China, in
   the country of Song.—De Guignes.
466.  A large stone at JEgospotamos, which
   Anaxagoras supposed to  come from the
   sun.  it was as large as  a cart, and of a
   burnt colour.—" Qui  .apis  etium  nunc
   ostenditim, magnitudine vents, colore adus-
   to."—Plutarch, Pliny, lib. ii. cap. 58. 
MET                                  MET
465.  A stone  near Thebes.—Scholiast of
  Pindar.
461.  A stone fell in the Marsh of  Ancona.
  — Valerius .\Li.v:inns, Liv. lib. vii. cap. 28.
343.  A shower of stones fell near Rome.—•
  Jul. Obsequens.
211.  Stones fell hi China, along with a
  fallin  ■ star.  De Guignes, &c.
205 or 2J6.   Fiery su.iies.—Plutarch, Fab.
  Mux. cap.  2.
192.  Stone fell in China.— De Guignes.
176.  A stone fell in the Lake of Mars.—
  " Lapidem  in Agro Crustumino in Lucum
  Martis d,- ccclo ceciduse."—Liv. xii. 3.
90 or 89.  " Eodem causam d<eente, lateribus
  coctis  phiisse, in ejus anni  acta relatum
  est."—Pltn. Nat. Hist. lib. ii. cap. 56.
89t  Two large stones fell at Yong in Chi-
  na. The sound was heard over 4 J leagues.
  —De Guignes. ■
56 or 52.  bpongy iron fell in Lucania.—
  Plin.
46.   Stones fell at Acilla.— Cxsar.
38.   Six stones fell in Leang in Cluna.—De
   Guignes.                      ^
29.   Four stones fell at Po in China. -De
   Guignes.
22.   Eight stones fell from heaven, in Chi-
  na___De Guignes.
12.   A  stone fell at  Ton-Kouan.—De
   Guignes.
9.  Two StotHs fell in China.—De Giugnes.
6.  Sixteen stones fell in Ning-Tcheon.and
  other two  in the same year.—De Guignes.

Division IT - Contai ning those, of which the
        date cannot be  determined.
The  Mother of the-  Gods which fell at Pes-
   sinus.
The stone preserved a+ Abydos. - Plin.
The stone preserved at Cassandria.—Plin.
The Black stone, and also another preserv-
   ed in the Caaba of Mecca.
The  '• Thunderbolt,  black in appearance
   like a hard rock, brilliant and sparkling,"
   of which the blacksmith forged the sword
   of Antar.—See  Quarterly  Revieno, vol.
   xxi p. 225. and Antar, translated by T.
   Hamilton, Esq. p. 152.
Perhaps the stone preserved in the Corona-
    tion Qhair of the Kings of England.

     Section 2.—After the Christian Era.
P.  C.
A stone in the country  of the Vocontini—
   Plin.
452.  Three large stones fell  in Thrace.—
   Cedrenus and Marcellini, Chronicon, p. 29.
   —"Hoc tempore," says Marcellinus, "tres
   magni lapides  e ccelo in  Thracia cecide-
   runt.''
 Sixth  Century.  Stones  fell  upon Mount
   Lebanon,  and  near Emisa  in  Syria.—
   Damascius.
 About  570.  Stones near Bender in Arabia.
 —Alkoran, vi. 16. and cv. 3. and 4,
648.  A  fiery stone at Constantinople.—
  Several Chronicles.
823.  A shower of pebbles in Saxony.
852.  A. stone fell in Tabaristan, in July or
  August.—De Sacy and Quatremere.
897.  A stone fell at Ahmedahad.— Qtlatre-
  m.-re.   In  892, according to the Chron.
  Syr.
951.  A  stone fell near Augsburg.—Alb.
  Sad. and others.
998.  Two stones  fell, one near the Elbe,
  and the other in the town of Magdeburg.
  — Cosmas and Spangenberg.
1009.  A mass of iron fell in Djordjan.—
  Avicenna.
1021.  Stones fell  in Africa between the
  24th July and the 21st of August.—De
• Sacy.
1112.  Stones or iron fell near Aquileja.—
   f'alvasor.
1135  or 1136.  A stone fell at  Oldisleben,
  in Thuringia.—Spangenberg, and others.
1164.  During Pentecost, iron  fell in Mis-
  nia.—Fubricius.
1198.  A stone fell near Paris.
1249.  Stones fell at Quedlinbourg, Ballen-
  stadt and Blankenburg, on the 26th July.
  —Spangenberg and Rivander.
 Tlrirteenth Century.  A stone fell at Wurz-
  burg.—Schotlus, Phys. Cur.
Between  1251  and  1363.  Stones fell  at'
   Welixoi-Ussing in Russia.— Gilbert's An-
  nal. torn. 35.
 1280. A stone fell at Alexandria in Egypt.
     De  Sacy.
 1304, Oct. 1.  Stones fell at Friedland or
   Friedberg.—Kranz and Spangenberg.
 130Z.  Stones fell  in the  country of the
   Vandals.
 1328, Jan. 9. In Mortahiah and Dakhaliah.
   — Quatremere.   »
 1368. A mass of iron in the Duchy of Ol-
   denburg.—Siebrand, Meyer.
 1379, May 26.  Stones  fell at  Minden in
   Hanover__Lerbecius.
 1438.  A shower  of spongy stones at  Roa,
   near Burgos in Spain.—Proust.
 ---   A stone fell near Lucerne.— Cysat.
 1491, March 22.   A stone fell near Crema.
   —Simoneta.
 1492, Nov. 7. A stone of 260 lb. fell at
   Ensisheim near Sturgau, in Alsace.  It is
   now  in the library of Colmar, and has
   been  reduced  to 150 lb.—Trithemius,
   Hirsaug. Annal.  Conrad Gesner,  Liber de
   Rerum Fossilium Ftguris, cap. 3. p. 66.
   in his  Opera, Zurich, 1565.
 1496, Jan.  26 or 28.  Three stones fell be-
   tween Cesena and Bertonori.—Burielmd
   Sabellicus.
 1510.  About 1200 stones,  one of which
   weighed  120 lb. and others 60 lb. fell in
   a field near the river Abdua.—"  Color
  ferrugineus, durities eximia, odor sulphu-
   reus."—Surius,   Comment.  Cardan,  De
   rerum Varietate, lib. xiv. c. 72. 
MET                                   MET
1511, Sept. 4.  Several stones, some  of
  which weighed  11 lb. and others 8 lb.
  fell at Crema—Giovanni  del  Prato, and
  others.
1520,  May.   Stones fell  in  Arragon___
  Diggo de Sayas.
15407Apri^28.  A stone fell in  the Limou-
  sin.—Bonav, de St. Amable.
Between 1540 and 1550.  A  mass of iron
  fell'in the forest <>f Naunhoff.— Chronicle
  ofthe Mutes of Misnia.
----  Iron fell in Piedmont.—Mercati and
  ScaUger.
1548, Nov. 6.  A black mass fell at Mans-
  field in  Thuringia.—Bonav. de St. Ama-
  ble.
1552, May 19.  Stones fell  in Thuringia
  near  Schlossingen.  Spangenberg.
1559.   Two  large  stones, as.large  as  a
  man's head, fell at Miscolz in Hungary,
  which  are said  to be preserved in the
  Treasury at Vienna.—Sthuansi.
1561, May 17.  A stone  called the Arx
  Julia, fell  at  Torgau and  Eilenborg.—
  Gesner  and De Boot.
1580, May 27.  Stones fell  near Gottingen.
  —Bange.
1581, July 26.  A  stone, 39 lb. weight, fell
  in Thuringia.  It  was so hot that no per-
  son could touch  it.—Binhard, Olearius.
1583, Jan. 9.   Stones fell at Castrovillari.—
  Casto, Mercati and Imperati.
1583, in the Ides of Jan.  A  stone of 30 lb.
  resembling iron, fell at Rosa in Lavadie.
----March 2.  A stone fell in "Piedmont of
  the size of a grenade.
1591, June 19.  Some  large stones fell at
  Kunersdorf.—Lucas.
1596, March  1.  Stones fell at Crevafcose.
  —MittareUL
In  the Sixteenth Century,  not  in 1603.   A
  stone fell in the kingdom of  Valencia.—
   Casius and the Jesuits of Coimbra.
1618, August.   A great fall of stones took
  place in Styria.—Stammes.
----A metallic mass  fell in  Bohemia—
  Kronland.
1621, April 17.  A mass of iron  fell about
  100 miles S. E.  of Lahore.—Jehan Guir's
  Memoirs.
1622. Jan. 10.  A stone fell in  Devonshire.
  —Rumph.
1628, April 9.   Stones  fell near Hatford in
  Berkshire; one of them weighed 24 lb.—
   Gent. Mag. Dec. 1796.
 1634, Oct 27.  Stones fell in Ckarollois.—
  Morinus.
 1635,  June 21.  A  stone  fell  at Vago in
   Italy.
 .----July 7, or Sept. 29.  A stone,  weigh-
   ing about 11 oz. fell at Calce.— Valisnieri,
   Opere, vi. 64.
 163§, March 6.  A burnt looking stone fell
   between Sagan and Dubrow in Silesia.—
   Lucas and Cluverius.
 1637, Nov. 29.   6asse»dj says, a stooe of
  a black  metallic colour,  fell on  Mount
  Vaision,  between Guilliaumc and Peine
  in Provence.   It weighed 54 lb. and had
  the size and shape  of the human head.
  Its specific .gravity  was  3.5.—Gassendi,
  Opera, p. 96. Lyons, 1658.
1642,  August 4.   A stone  weighing 4 lb.
  fell between VV'oodbridgeand Aldborough
  in Suffolk—Gent. Mag. Dec. 1796.
1613,  or 1644.  Stones fell in the  sea.—
  Wuofbrain.
1647,  Feb. 18.  A stone fell near Fwicxau.
  — Schmid.
----August.  Stones fell  in the bailliage
  of  Stolzenem in Westphalia —Gilbert's
  Annal.
Between 1647 and 1654.  A mass fell in the
  sea.— Willman.
1650, August 6.   A stone fell at Dordrecht.
  —Senguesd.
1654, March 30.  Stones fell  in the Island
  of Funen.—Bartholinus.
A large stone fell at Warsaw.—Petr. Borel-
  lus.
A smafl*, stone  fell at Milan, and killed a
  Franciscan.—Museum Septalianum.
1668, June 19. or 21.   Two stones, one 300
 . lb.  and the other 200 lb.  weight, fell near
  Verona.  Legallois,  Cojiversations,  &c.
  Paris 1672, Valisnieri,  Opere, ii. p. 64. 66.
  Montanan and Francisco  Carli, who pub-
  lished a letter, containing^veral curious
  notices respecting  the fall of stones from
  the heavens.
1671, Feb. 27.   Stones  fell  in  Suabia.—
   Gilbert's Annal. torn, xxxiii.
1673.  A stone fell in the  fields near Diet-
  ling.—" Nostris temporibus in partibm
   Gallite Cispadame, lapis magnte quttntitatis
  e nubibus  cecidit."—See  Leonardus, de
   Gemmis, lib. i. cap. 5.;  and Memorie  delta
   Societa Colombaria Fiorentina, 1747, voL i.
  diss.  vi. p. 14.
 1674, Oct. 6.  Two large  stones fell  near
   Claris.—Scheuchzer.
 Between  1675 and 1677.   A stone fell into
   a  fishing-boat  near Copinshaw. —Wal-
   lace's Account of Orkney, and  Gent. Mag.
   July  1806.
 1677, May 28.   Several stones,  which pro-
   bably contained copper, fell at  Erniun-
   dorf near Roosenhaven.—Misi, Nat.  Cur.
   1677. App.
 1680, May 18.   Stones fell  at London —
   A'ing.
 1697, .tan. 13.  Stones fell  at Pentolina near
   Sienna.—Soldani after Gabrieli.
 1698, May 19.  A stone fell at  Walhing.—
   Scheuchzer.
 1706, June 7.   A stone of 72 lb. fell at I.a-
   rissa in Macedonia.   It smelled  of sul-
   phur, and was like the  scum  of iron.—
   Paul Lucas.
 1722, June 5.  Stones fell  near Scheftlas in
   Freisingen.- Meii helbeck.
 1723, June 22,  About 33 stones, black and 
MET                                 MET
   metallic, fell near Plestowitz in Bohemia.
   —Rostand Stepling.
 1727, July 22.  Stones fell at I.ilaschitz in
   Bohemia.—Steplintr
 1738, August 18.   Stones fell near Carpen-
   tras. — Casrillon.
 174., Oct. 25.  Stones  fell at  Rasgrad.—
   Gilbert's Annal. torn. 1.
 ——to 1741.  A  large  stone fell in winter
   in Greenland. —F.gede.
 1743. Stones fell at Liboschitz in Bohemia.
   —Stepling.        ,
 1750, Oct. 1.  A  large  stone fell  at Niort
   near Coutance.—Huard and Lalande.
•1751, May 26.  Two masses of iron of 71 lb.
   and 16 lb. fell  yi the district  of Agram,
   the capital of  Croatia.  The largest of
   these is now in Vienna.
 1753, Jan. A stone fell in Germany, in*Eich-
   stadt.— Cavallo, iv. 377.
 ----July 3.   Four stones,, one of which
   weighed 13 lb. fell at btrkow, near Tabor.
   —Stepling,  " De  Pluvia  lapidea.  anni
   1753, ad Strkow, et ejus causis, meditatio,''
   p. 4.—Prag. 1754.
 ----Sept.  Two stones, one of 20 lb. and
   .the other of 11  lb. fell near the villages
   of Liponas and  Pin in Brene.—Lalande
   and Richard.
 1755, July.  A stone fell  in Calabria, at
   Terranuova, which weighed 7 lb. 7£ oz.
   — Domin. Tata.
 1766, end of July.  A stone fell at Albereto
   in Modena.— Troili.
 ----August 15.  A stone fell at Novellara.
   — Troili.
 1768, Sept.  13.  A stone fell near Luce in
   Maine.  It was analyzed by Lavoisier, &c.
   —Mem. Acad. Par.
 ----A stone fell at Aire.—Mem. Acad. Par.
 1768, Nov. 20.  A stone,  weighing 38  lb.
   fell at Mauerkirchen  in Bavaria.—Imhof.
 1773, Nov. 17.  A  stone, weighing 9 lb. 1
   oz. fell at Sena in Arragon.—Proust.
 1775, Sept. 19. Stones fell near Rodach in
   Cobourg.— Gilbert's Annal. torn, xxiii.
 ----or 1776.  Stones fell  at Obruteza in
   Volhynia.—Gilbert's Annal. torn. xxxi.
 1776 or 1777, Jan. or Feb. Stones fell near
   Fabriano.—Soldani and Amoretti.
 1779. Two stones, weigning 3^ oz. each,
   fell at Pettiswoode in Ireland.—hi.iglaj,
   in Gent. Mag. Sept. 1796.
 1780, April 1.   Stones fell near  Becstonin
   England. — Evening Post.
 1782.  A stone fell near Turin.—Tata, and
   Amoretti.
 1785, Feb. 19.  Stones fell at Eiclistadt.—
   Picket and Stalz.
 1787, Oct. 1.   Stones fell in the province of
   Charkow in Russia.—Gilbert's Annah torn.
   xxxi.
 1790, July  24.  A great shower of stones
   fell at Barbotan near Roquefort, in the
   vicinity of Bordeaux.   A mass, 15 inches
   in diameter, penetrated a hut, and killed
   a herdsman and a bullock.  Some ofthe.
   stones weighed 25 lb. and others 30 lb.—
   Lomet.
 1791, May 17.  Stones fell  at Cassel-Ber-
   ardenga, in Tuscany.—Soldani.
 1794, June 16. Twelve stones, one of which
   weighed 7\ oz. fell at Sienna.   Howard
   and Klaproth have analyzed these stones.
   —Phil.  Trans. 1794, p. 103.
 1795, April 13.  Stones  fell at  Ceylon.—
   Beck.
 ----Dec. 13.   A large stone, weighing 55
   lb.  fell near Wold Cottage in Yorkshire.
   No light  accompanied  the  fall.— Gent.
   Mug. 1796.    *
 1796, Jan. 4. Stones fell near Belaja-Ferk-
   wa  in Russia.—Gilbert's Annal. torn xxxv.
 ----Feb. 19.   A stone of 10 lb. fell in Por-
   tugal.—Southey's Letters from Spain.
 1798, March 8. or 12.  Stones, one of which
   was the size of a calf's head, fell at Sales.
   —Marquis de Dree.
 ----Dec. 19.    Stones fell in Bengal.—
   Howard, Lord Valentia.
 1799, April 5.  Stones  fell at Batonrouge on
   the Mississippi.— Belfast  Chronicle ofthe
   War.
 1801.   Stones fell on ihe Island of Tonne»
   liers.—Bory de St. Vincent.
 1802,  Sept. Stones fell in Scotland? Month-
   ly Magazine, Oct.  1802.
 1803,  April 26.  A great fall of stones took
   place at Aigle.  They  were about three
   thousand  in  number,  and  tne  largest
   weighed about 17 lb.
 ----Oct.  5.   Stones fell near Avignon.-—
   Bibl. Brit.
 ----■ Dec. 13.  A stone fell near Eggen-
   felde in  Kavaria, weighing 3$ lb.—Imhof.
 1804,  April 5.  A stone fell at  Possil, near
   Glasgow.
 ------1807.  A stone fell at Dordrecht.—
   Van Beek.  Culkoen.
 1805, March  25.  Stones  fell at  Doronins
   in Siberia.— Gilbert's Annal.  torn. xxix.
   and xxxi.
 ----June.   Stones,  covered with  a blacla
   crust, fell in Constantinople.
 1806,  March  15.  Two stones fell at  St.
   Etienne and Valence; one of them weigh-
   ed 8 lb.                            6
 ----May 17.  A stone weighing 2$ lb. fell
   near Basingstoke in Hampshire.—Month*
   ly *uaga:i,ie.
 1S07,  March  13.  (June  17, according to
   Lucas}.  A stone of 160 lb. fell  at Fim-
   ochin, in the  province  of Smolensko in
   Russia.—Gilbert'*- Annal.
 ----Dec. If.  A great shower of stones
 •fell near Weston in Connecticut.  Masses
 .of 20 lb. 25 lb. and 35 lb. were found.—
   Silliman and Kinsrsley.
 1808, April 19.   Stones fell at Borgo Sam
  Donino.—Cuidotti zndSpagnoni.
----May 22.  Stones w&hing- 4 lb. or 5 lb.
  feh near Stannem m Moravia.—JSibl^ frit, 
MET
MET
1808, Sept. 3.   Stones fell at Lissa in Bo-
  hernia.-De Schreibers.
1809, June 17.   A stone of 6  oz.  fell on
  board an American vessel, in latitude 30°
  58' N., and longitude  70° 25'  W.—Bibl.
  Brit.
1810, Jan.  30.  Stones,  some of which
  weighed about 2 lb. fell in Caswell coun-
  ty, North America.—Phil.  Mag. -vol.
  xxxvi.
----July.   A great  stone fell at Shahabad
  in India.  It burned  five  villages,  and
  killed several men and women.—Phil.
  Mag. xxxvii. p. 236.
---- Aug. 10.   A stone*weighing 7|  lb.
  fell in the county of Trpperary in Ireland.
  —Phil. Mag. vol. xxxviii.
.---- Nov. 23.  Stones fell  at  Mortelle,
  Villerai, and  Moulinbrule, in the  depart-
  ment of the Loiret; one of them weighed
  40 lb. and the other 20 lb.—Nkh. Jour-
  nal, vol. xxxix. p. 158.
1811, March 12 or  13.  A stone  of 15 lb.
  fell in the village of Konglinhowsh, near
  Romea  in  Russia.—Bruce's  American
  Journal, No. 3.
1811, July 8. Stones, one of which weighed
  3J oz. fell near Balanguillas in Spain —
  Bibl.  Brit. torn, xhftii. p. 162.
1812, April 10.  A  shower of stones fell
  near Thoulouse.
—— April 15. A stone,  the size of a child's
  head, fell at Erxleben.  A specimen of it
  is in  ttm possession of  Professor Hauss-
  man  of Brunswick.— Gilbert's Annal. si.
  and xli.
----Aug.  5.   Stones fell at Chantonay.—•
  Brochant.
1813, March 14.  Stones  fell  at  Cutro in
  Calabria, during a great fall of red dust.
  —Bibl. Brit.  Oct. 1813.
----Sept. 9. and 10. Several Stones, one
  of which weighed 17  lb. fell near Lime-
  rick in Ireland.—Phil. Mag.
1814, Feb. 3.   A stone  fell near  Bacharut
  in Russia. — Gilberts Annal. torn. 1.
----Sept. 5. Stones, some of which weigh-
  ed 18 lb. fell in the  vicinity of Agen.—
  Phil. Mag. vol. xlv.
■---Nov.  5.   Stones,   of which  19  were
  found, fell in  the  Doab  in India.—Phil.
  Mag.
1815, Oct. 3.   A large  stone fell at Chas-
  signy near Langres.—Pisto'let.
1816.  A stone fell  at  Glastonbury in So-
  mersetshire.—Phil. Mag.
1817, May 2. and 3.  There  is  reason to
  think, that masses of stone  fell in the
  Baltic after the great meteor of Gotten-
  burg.— Chladni.
1818, Feb. 15.   A great stone appears to
  have  fallen at Limoge, but it  has not
  been  disinterred.— Gazette de  France,
  Feb.  25, 1818.
----July 29. O. S.   A stone of 7 lb. fell at
  the village  of Slobodka in Smolensko.
  It penetrated  nearly  16  inches  into the
  ground.  It had a brown crust with me-
  tallic spots.

List  of  Massi.s of Ino\ surposed to havj
       FALLEN FROM THE HKAVENS.

    Sect  1.—Spongy or  Cellular Masses
            containing .\ickel
1. The mass  found by Pallas in Siberia, to
  which  the Tartars ascribe a meteoric ori-
  gin.— Voyages de Pyllas, torn. iv. p. 545.
  Paris 1793.
2. A  fragment found between Eibenstock
  and Johanngeorgenstadt.             f
3. A fragment probably from Norway, and
  in the imperial cabinet of Vienna.
4. A  small  mass  weighing some pounds,
  anoVnow at Gotha.
5. Two mass in Greenland,  out  of which
  the knives  of,the Esquimaux were made.
  —See  Ross s Account of an Expedition to
  the  Arctic Regions.

Sect. 2.—Solid Masses where tlie Iron exists
  in  Rhomboids or Octahedrons, composed of
  Strata, and containing Nickel.

1. The only  fall of iron of this  kind, is
  that which  took  place at Agram, in 1751.
2. A mass ofthe same kind has been found
  on the  right bank of the  Senegal.— Com-
  pagnon, Forster,  Goldberry.
3. At the Cape of Good  Hope;  Strome-
  yer has lately detected cobalt in this mass.
  — Van Maritm and Dankelman ; Brandt's
  Journal, vol. vi. 162.
4. In   different  parts of Mexico.— Sonne-
  schmidt, Humboldt, and the  Gazette  de
  Mexico, torn. i. and v.
5. In the province of Bahiain Brazil   It
  is seven feet long, four feet wide, and two
  feet thick, and its weight about 14,000 lb.
  —Mornay  and  Wollaston; Phil. Trans.
  18l6,p. 270. 281.
6. In   the  jurisdiction  of  San Jago  del
  Estera.—Rubin  de  Ccelis,  in  the Phil.
  Trans. 1788, vol. Ixxviii. p. 37.
7. At Elbogen  in  Bohemia.— Gilbert's  An.
  nal. xlii. and xliv.
8. Near Lenarto in Hungary.—Ditto, xlix.
The origin ofthe following masses seems to
  be uncertain, as  they  do not contain nic-
  kel, and have a different texture from the
  preceding:—
1. A mass found nea* the  Red River, and
  sent from New Orleans to New  York.—
  Journ. des Mines  1812, Bruce's Journ.
2. A  mass at  Aix-la-Chapelle, containing
  arsenic— Gilbert's Annal. xlviii.
3.'Amass found on the hill of Brianza in
  the Milanese.— Chladni, in Gilbert's Annal.
  1. p. 275.
4. A  mass found at Groskamdorf, and con-
  taining, according to Klaproth,  a little
  lead and copper. 
MIA
MIE
   Nickel or chromium is found to be the
 constant associate of the iron in the meteor-
 olites.  It is characteristic of meteoric iron,
 as it is never found in mineral native iron.
   Nickel has been hitherto regarded as the
 sole characteristic ingredient of meteoric
 stones, but from the analysis of some  late
 meteorolites, it would appear, that this me-
 tal is occasionally  absent, while chromium
 is always found. Hence the latter has come
 to he viewed as the constant characteristic.
   The phenomenon  of red snow observed at
 Baffin's Bay, has of late excited some specu-
 lation,  being supposed to  be a meteoric
 phenomenon. But Mr. Bauer has proved by
 microscopic examination, that the colouring
 particles consist of a new species of the ure-
 do, which grows upon the snow, to which he
 has given the appropriate name of uredo ni-
 valis.  He found the real diameter of an in-
 dividual full grown globule of this fungus, to
 be the one thousand six hundredth part of an
 inch.  Hence,  in  order to cover a single
 square inch, two million five hundred and
 sixty  thousand of  them  are  necessary.
 Journal of Science, vol. vii.p. 222.*
   * Meteorologt.  See  Climate,  Dew,
 Uaiw.*
   * Miasmata.  Vapours or effluvia, which
 by their application to the human system,
 are capable of exciting  various diseases,  of
 which the principal are intermittent, remit-
 tent, and yellow fevers, dysentery  and ty-
 phus.  That of the last is generated in the
 human body kself, and is sometimes called
^the typhoid fomes. The other miasmata are
 produced from  moist vegetable matter,  in
 some unknown state of decomposition. The
 contagious virus of the plague, small-pox,
 measles, chincough,  cynanche maligna, and
 scarlet fever, as well as of typhus and the jail
 fever, operates to  a much more limited dis-
 tance through the intermedium ofthe atmos-
 phere, than the marsh miasmata.  Contact
 of a diseased person  is said to be necessary
 for the communication of plague; and ap-
 proach within 2 or 3 yards of him, for that
 of typhus.   The Walcheren miasmata ex-
 tended their pestilential influence to vessels
 riding at anchor, fully a quarter of a mile
 from the shore.
   The chemical nature of all these poison-
 ous effluvia is little understood.  They un-
 doubtedly consist, however,  of hydrogen,
 united with sulphur, phosphorus, carbon,
 and  azote,  in unknown proportions, and
 unknown states of combination.  The proper
 neutralizes or destroyers of these gasiform
 poisons, are nitric acid vapour, muriatic acid
 gas, and chlorine.   The last two  are  the
 most efficacious; but require to be used in
 situations from which the patients can be
 removed  at the time of the application.
 Nitric  acid  vapour may, however, be  dif-
 fused in the apartments ofthe sick, without
 much inconvenience.   Bed-clothes, par-
   VOL.  \t
ticularly blankets, can retain the contagious
fomes, in an active state, for almost any
length of time.  Hence, they ought to be
fumigated, with peculiar care.  The vapour
of burning sulphur or  sulphurous acid is
used in the East against the plague.  It is
much inferior in power to the other antiloi-
mic reagents.*
   *  Mica.  Professor Jameson subdivides
this mineral species into ten  sub-species;
viz. mica, pinite, lepidolite, chlorite, green
earth, talc, nacrite, potstone,  steatite, and
figure-stone.
   Misa.  Colours, yellowish and greenish-
 gray.   Massive, disseminated, and crystal-
lized.   Its primitive  figure is a rhomboid.
The secondary  forms are; an equiangular
six-sided  prism, or  table; a rectangular
four-sided prism, or  table; and a six-sided
pyramid.   Lateral planes smooth and splen-
dent ;  terminal, longitudinally  streaked.
Lustre pearly, or semi-metallic.  Cleavage
single.  Fragments tabular and splintery.
Translucent. Sectile.  Streak gray-colour-
ed.  Harder than gypsum,  but not so hard
as calcareous spar.  Feels meagre or smooth.
Elastic-flexible.   Sp. gr. 2.65.  Before the
blow-pipe it melts into a grayish white en-
amel.  Its constituents are, silica 47, alu-
mina 2%, oxide of  iron 15.5, oxide ofman-
ganese 1.75, potash 14.5.—Klaproth.  It oc-
curs along with feldspar and quartz in feld-
spar and gneiss.  It sometimes forms short
beds, in granite  and other primitive rocks.
Most of the mica of  commerce is brought
from Siberia, where it is used for window-
glass.*
   Michocosmic Salt.  A triple salt of so-
da, ammonia, and phosphoric acid, obtain-
ed from urine, and much used in assays by
the blow-pipe.
  * Miemite; of which there are two kinds,
the granular and prismatic,  both sub-spe-
cies of dolomite.
   Granular miemite. Colour pale asparagus-
green.  Massive, in  granular distinct con-
cretions,  and  crystallized  in  flat double
three-sided  pyramids.   Lustre  splendent,
pearly.  Cleavage  threefold oblique angu-
lar.   Translucent.  Semi-hard.   Brittle.
Sp. gr. 2.885.  It dissolves slowly, and with
little effervescence, in cold nitric acid. Its
constituents are, carbonate of lime 53, car-
bonate of magnesia 42.5, carbonate of iron,
with a little  manganese, 3.0.  It is found
at Miemo  in  Tuscany, imbedded in gyp-
sum, at Hall in the Tyrol, and in Greenland.
  Prismatic miemite.    Colour  asparagus
green.  It occurs in prismatic distinct con-
cretions, and crystallized in flat rhomboids,
which are deeply  truncated on all  their
edges.  Internally shining. Fracture passes
from  concealed  foliated  to  splintery.
Strongly translucent.  As hard as the for-
mer.  Sp. gr. 2.885.  It dissolves like the.
other.  Its constituents are, lime 33, mag-
                  24 
MIL
MIL
nesia 14.5, oxide of iron 2.5, carbonic acid
47.25, water and loss 2.75.—Klapr.  It oc-
curs in cobalt veins that traverse sandstone,
at Glucksbrunn in Gotha.*
  Mi • r is  a well known fluid, secreted in
peculiar vessels ofthe females ofthe human
species, of  quadrupeds, and  of cetaceous
animals, and destined for the purpose of
nourishing their young.
  When milk is left to spontaneous decom-
position, at  a due temperature, it is found
to be capable of passing through the vinous,
acetous, and putrefactive fermentations.  It
appears, however, probable on account of
the small quantity of alcohol it affords, that
the vinous fermentation  lasts  a very  short
time, and  can scarcely  be  made to take
place in every part of the fluid at once by
the addition of any ferment.   This seems
to  be  the  reason, why the  Tartars, who
make  a permanent liquor, or wine, from
mare's milk,  called koumiss, succeed by
using large quantities at a time, and agitating
it very frequently. They add as a ferment a
sixth part of water, and an eighth part ofthe
sourest cow's milk they can get, or a smaller
portion of koumiss already prepared;  cover
the vessel with a thick cloth, and let it stand
in a moderate warmth tor 24 hours; then
beat it with a stick, to mix the thicker and
thinner parts, which have  separated; let  it.
stand again  24 hours in a high narrow ves-
sel, and repeat the beating, till the liquor is
perfectly  homogeneous.  This liquor will
keep some months, in close vessels, and  a
cold place; but  must  be well mixed by
beating or  shaking every time it is used.
They sometimes extract a spirit from it by
distillation.  The  Arabs prepare  a similar
liquor by the name of leban, and the Turks
by  that of  yaourt. Eton informs us, that,
when properly prepared,  it  may be left to
stand till it becomes quite dry ; and in this
state it is kept in bags, and mixed with wa-
ter when wanted for use.
  The saccharine  substance, upon  which
the fermenting property of milk  depends,
is held in solution by the  whey, which re-
mains after the separation of the curd  in
making cheese.  This is separated by eva-
poration in  the large way, for pharmaceuti-
cal purposes,  in various parts  of Switzer-
land.  When the whey has been evaporated
 by heat, to the consistence of honey, it is
 poured into proper moulds, and exposed to
 dry in the sun.  If this crude sugar of milk
 be  dissolved in water, clarified with  whites
 of eggs, and evaporated to the consistence
 of s:rup,  wh;te  crystals, in the  form  of
 rhomboidal parallelopipedons, are obtained.
    Sugar of milk has a faint saccharine taste,
 aiid is soluble in three or four parts  of wa-
 ter. It yields by distillation the same pro-
 Jictsthat other sugars do, only in somewhat
 different   proportions.  It is  remarkable,
 however,  that the empyreumatic  oil has a
 smell resembling flowers of benzoin.   It
contains an acid frequently  called the sac-
cholactic; but as it is common to all muci-
laginous substances, it has been termed mu-
cic.  See Acid (Mu re).
  The kinds of milk  that have been chemi-
cally examined, are  mare's, woman's, ass's,
goat's, sheep's, and cow's.  We have here
placed them according to the proportion of
•ti^arthey  afforded; and this, Parmentier
observes, was precisely of the «ame quality
in all, while all the  other  parts varied  in
quality as well as quantity  in the different
milks.   With regard to the whey, they rank
in the following order; ass's, mare's, wo-
man's, cow's,  goat's, sheep's: to cream,-
sheep's, woman's, goat's, cow's, ass's, mare's:
to butter,- sheep's, goat's, cow's, woman's:
to cheese ,- sheep's, goat's, cow's, ass's, wo-
man's, mare's.  Parmentier could not make
any butter from the cream of woman's, ass's,
or mare'smilk; andthatfrom sheep he found
always remained  soft.  From their general
properties, he has divided them into two
classes ; one abounding  in serous and saline
parts, which includes ass's,  mare's, and wo-
man's; the other rich in caseous and buty-
raceous parts, which are cow's, goat's, and
sheep's.
   * Cream, sp.  gr.  1.0244 by Berzelius's
analysis, consists of  butter 4.5, cheese 3.5,
whey  92.  Curd, by the  analysis of MM.
Gay-Lussac and Thenard, is composed of
            Carbon,    59.781
            Oxygen,    11.400
            Hydrogen,   7.429
            Azote,      21.381         J|

                       100.000
   Whey always  reddens  vegetable blues,
from the presence of lactic acid.   Milk, ac-
cording to Berzelius, consists of,
   Water,    ....    928.75
   Curd, with a little cream,       28.00
   Sugar of milk,      -      -    35.00
   Muriate of potash,  -      -      1.70
   Phosphate of potash,       -      0.25
   Lactic acid, acetate of potash,}
     with  a trace of lactate of V-  6.00
     iron,     -     -     -    J
   Earthy  phosphates,     -    -    0.30

                                1000.00
   Since both cream and water affect the spe-
  cific gravity of milk alike, it is not possible
  to infer the quality  of milk from the indica-
  tions merely of a specific gravity instrument.
  We must first use as a lactometer, agraduated
  glass tube, in which we note the  thickness
  of the stratum  of cream  afforded,  after a
  proper interval, from a determinate column
  of new milk.  We then apply to  the skim-
  med milk, a hydrometric instrument, from
  which we learn the relative proportions of
  curd and whey.  Thus, the  combination of
  the two instruments furnishes a tolerably e\-'
  act lactometer.*
   * MfLK-ftUAIlTZ.   SeeQrARTz*. 
M1N                                   MIN
  * Mineralogy.  That department of na-
tural history which teaches us to describe,
recognize, and classify, the different genera
and species of the objects of inorganic na-
ture.  As the  greater  part of these are so-
lids, extracted from the earth by mining,
they are called Minerals. The term Fossil
is now commonly  restricted to such forms
of organic bodies,  as have been penetrated
with earthy or metallic matters.
  Professor Mohs of Freyberg, has lately
published a work, replete with profound ge-
neral views on mineralogy, which promises
to place the science on a surer basis than it
has hitherto stood.
   Werner first taught mineralogists to con-
sider the productions of  inorganic nature in
a state of mutual connexion,  resulting from
mineralogical  similarity.   Thus, heavy spar
is plainly  more similar to  calcareous  spar,
than feldspar is; feldspar than garnet; gar-
net than iron-glance;  iron-glance than na-
tive gold  ; and so on.
   A collection of  species connected by the
highest, and at the same time, equal degrees
of natural-history  similarity, is named a ^e-
nus.  The same occurs in zoology and bo-
tany.  Thus,  the  wolf, dog, fox ; the lion,
tiger, cat, unite into  genera.   Individuals
whose forms belong  to  two different sys-
tems of crystallizations, cannot be united in
the  same species. Radiated hepatic, and
cristated iron  pyrites, therefore, constitute
a distinct species. Yet  this species  is  so
^imilar to that of common iron pyrites (tes-
^lar),  that we must  unite them into one
genus.
   An order comprehends several analogous
genera; and a class, analogous orders.
  The  specific character consists particu-
larly of three characters.  These are the
crystalline forms, (including cleavage), the
degrees of hardness,  and the specific gra-
vity. The crystalline forms may be reduced
in all cases to  one of four Systems of Crys-
tallization ; the Rhombohehral:  the Py-
ramidal,  derived from a four-sided isosce-
les pyramid;  the Prismatic, derived from
a scalene  four-sided pyramid ; and lastly the
Trssitlar, or that which is derived from the
hexahedron.
  Whew we wish to determine the species
to which  any  mineral belongs; by means of
a tabular view, we must first ascertain either
its primitive form or  cleavage,  and  after-
wards the hardness  and  specific  gravity.
The degrees of hardness are expressed  by
Mohs in the following manner:
  1 expresses the hardness of Talc,
  2                        Gypsum,
  3                        Calcareous spar,
  4                       Fluorspar,
  5                       Apatite,
  6                        Feldspar,
  7                       Quartz,
  8                        Topsr/,
 9 expresses the hardness of Corundum,
10                          Diamond.
  Professor Mohs has arranged minerals in
to three classes.
      I. Character ofthe first class.
  If solid;  sapid.  No  bituminous odour
Sp. gr. under 3.8.  It has 4 orders.
  Order 1. Gas.  Expansible.  Not acid.
  2. Water.  Liquid.  Without  odour  or
sapidity.  Sp. gr. 1.
  3. Acid.  Acid.  Specific gravity, 0.0015
to 3.7.
  4. Salt.   Not  acid.  Sp. gr. 1.2 to 2.9.
     II. Character of the second class.
  Insipid.   Sp. gr. above 1.8.
  Order 1. Haloide (salt-like).  Not metal-
lic.  Streak uncoloured.
  If pyramidal  or prismatic; H. hardness
 ■== 4 and less.  If tessular,  H.  = 4.0.   If
single, perfect, and eminent faces of cleav-
age ; sp. gr. =- 2.4 and less.
  H. = 1.5 to 5.0.  If under 2.5, sp. gr. =
2.4andless.  Sp. gr  = 2.2 to 3.3.  If 2.4
and less ;  H. under 2.5; and no  resinous
lustre.
            Order 2.  Baryte.
  Not metallic.  If adamantine or imperfect
metallic lustre; sp.  gr. =  6.0,  and more.
Streak  uncoloured,  or  orange-yellow.   If
orange-yellow;  sp.  gr.  =.  6.0  and more,
and H.  = 3.0 and less.
  H. = 2.5 to 5.0^  If 5.0; sp.  gr.  under
4.5.             •
  Sp. gr.  =- 3.3 to 7.2.   If under 4.0 and H.
= 5.0; cleavage dis-prismatic.
        Order 3.  Kerate (Horny).
  Not metallic.  Streak uncoloured.  No
single eminent cleavage. H. ■= 1.0 to 2.0.
Sp. gr.  — 5.5.
           Order 4.  Malachite.
  Not metallic.  Colour blue, green, brown.
If brown, colour of streak:   H.  = 3.0 and
less; and sp. gr. above 2 5.  If uncoloured
streak; sp. gr. = 2.2  and less; and H. •=
3.0.  No  single eminent faces of cleavage.
H.  = 2.0 to 5.0.   Sp. gr. = 2.0 to 4.6.
             Order 5.   Mica.
  If metallic : Sp. gr.  under 2.2.  If not
metallic:   Sp.  gr.  above  2.2.   If yellow
streak; pyramidal. Single eminent cleavage.
II.  = 1.0 to 4.5.  If  above  2.5; rhombohe-
dral.  Sp. gr. = 1.8  to 5.6.  If  under 2.5 5
metallic.   If above 4.4;  streak uncoloured.
             Order 6.   Spar.
  Not metallic.  Streak uncoloured, brown.
If  rhombohedral; sp.  gr. 2.2 and less, or
 H.  - 6.0.
  H. — 3.5 to 7.  If 4.0 and less;  single
eminent cleavage.  If  above 6.0; sp. gr.
under 2.5, or above  2.8 ; and pearly lustre.
 Sp. gr.  — 2.0 to 3.7.  If above 3.3 ; hemi-
prismatic, or H.  — 6.0 ; and no adamantine
lustre.  If 2.4 and less; not  without  traces
ef form and cleavage.
             Order 7.   Gem.
  Not  metallic.  Streak tmqoloured,   ¥Ly 
M1N
MIN
 -» 3.5 to 10.  If 6.0 and less; sp. gr. " 2A
 and less; and no traces of form and cleav-
 age.   Sp. gi     1.9 to 4.7.  If under 3.8;
 no pearly lustre.
              Order 8.   Ore.
   If metallic; black   If not metallic;  ada-
 mantine, or imperfert metallic lustre.  If
 yellow or red streak ; II.  — 3.5 and more ;
 and sp. gr.  = 4.8 and more.  If brown or
 black  streak; H. =  5.0 and more, or per-
 fectly  prismatoidal.   II.  =  2.5  to 70.  If
 4.5 and less; red, yellow, or black streak.
 If 6.5  and  more, and streak uncoloured;
 sp. gr. = 6.5  and more.  Sp. gr. = 3.4 to
 7.4.
             Order 9. Metal.
   Metallic.  Not black.  If gray;  malle-
 able ;  and sp. gr. =» 7.4  and more.   II. =
0.0 to 4.0 or  malleable.  Sp. gr.  = 5.7 to
 20.0.
            Order 10.  Pyrites.
   Metallic.  H. - 3 5 to 6.5.   If 4.5 and
 less; sp. gr. under 5.0   Sp, gr.  =4.1  to
 7.7.  If 5.3 and less;  colour yellow or red.
            Order 11.  Glance.
   Metallic.  Gray, black.  H. 1.0 to to 4.0.
 Sp.  gr. = 4.0  to 7.6.  If under 5.0,  and
single perfect cleavage; lead-gray. If above
 7.4; lead-gray.
            Order 12. Blende.
  If metallic;  black.  If not metallic; ada-
mantine lustre.  If brown  streak; uncolour-
ed.  Sp. gr. between 4#and 4.2;  and the
form tessular.   If red streak ; sp. gr. = 4.5
and more ;  and H. = 2.5 and less.
   II. = 1.0, 4.0.  Sp. gr. = 3.9, 8.2.   If
4.3 and more ; streak red.
          Order 13.  Sulphur.
  Not  metallic.  Colour  red,  yellow, or
brown.  Prismatic.   H. = 1.0 to 2.5.  Sp.
gr. =  1.9 to 3.6.  If above 2.1; streak yel-
low, or red.
                Class in.
  If fluid; bituminous odour.  If solid; in-
sipid.  Sp.gr. under 1.8.
            Order 1.  Resin.
  Fluid, solid.  Streak uncoloured, yellow,
brown, black.  II. = 0.0 to 2.5.  Sp. gr. =
0.7 to  1.6.  If 1.2  and  more;  streak un-
coloured.
             Order 2.  Coal.
   Solid. Streak, brown,  black.  H. = 0.1
to 2.5.  Sp. gr.  = 1.2 to 1.5.

                 Genera.

         Class I. Order 1.   Gas.
   Genera.   1. Hydrogen. 2. Atmospheric
 air.
            Order 2.  Water.
   Genus.  1. Atmospheric water.
             Order 3.  Acid.
 .  Genera.   1.  Carbonic.  2. Muriatic.   3.
 Sulphuric.   4.  Boracic; and 5. Arsenic.
             Order 4.  Salt.
   Genera.  1.  Natron-salt.  2.  Glauber-
 salt.  J, Nitre-salt.  4.  Rock-salt.  5.  Am-
 moniac-salt.  6. Vitriol-salt; comprising as
 species, the sulphates of iron, copper and
 zinc. 7. Epsom-salt. 8. Alum-salt.  9. Bo-
 rax-salt.   10.  Brythine-salt  (heavy-salt).
 Glauberite.
       Class II.  Order 1.  Haloide.
   Genera.  1  Gypsum-haloide.  *. Cryonc
 haloide. 3. Alum-haloide. 4. Fluor-haloide.
 5. Calc-haloide.
            Order 2.   Baryte.
   Genera.   1.  Parachrosc-baryte (altered
 colour).  2.  Zinc-baryte.  3. Scheelium-
 baryte.  4. Hal-baryte.   5. Lead-baryte.
            Order 3.   Kerate.
   Genera.   1.  Pearl-kerate.
           Order 4. Malachite.
   Genera.   1.  Staphy line-malachite (grape
 like).   2.  Lirocone-malachite  (form un-
 known).   3.  Olive-malachite.  4.  Azure-
 malachite.   5.  Emerald-malacliite.  6. Ha-
 broncme-malachite (fine threaded).
             Order 5.   Mica.
  Genera.  1. Euchlore-mica (bright-green).
 2.  Antimony-mica.   3.  Cobalt-mica.   4.
 Iron-mica.   5.  Graphite mica.   6. Talc-
 mica-  7.  Pearl-mica.
             Order  6.  Spar.
   Genera.   1.  Schiller-spar.  2. Disthene-
 spar. 3. Triphane-spar.  4. Dystome-spar
 (difficult to  cleave).   5.  Kouphone-spar
 (light). 6.  Petaline-spar.  7.  Feldspar.  8.
Augite-spar.   9.  Azure-spar.
             Order  7.  Gem.
  Genera.  1. Andalusite.  2. Corundum.
3. Diamond.   4.  Topaz.  5. Emerald. J&
Quartz: 7. Axinite. 8.  Chrysolite.  9. Bu^
racite.   10.  Tourmaline.  11. Garnet.  12.
 Zircon. 13. Gadolinite.
             Order  8.   Ore.
  Genera.  1. Titanium-ore.  2.  Zinc-ore.
 3. Copper-ore. 4. Tin-ore. 5. Scheelium-
 ore.  6. Tantalum-ore.  7. Uranium-ore.
 8. Cerium-ore.  9. Chrome-ore.  10. Iron-
 ore.  11. Manganese-ore.
             Order  9.  Metal.
  Genera.   1.  Arsenic.  2. Tellurium.  3.
 Antimony.  4.  Bismuth.  5.  Mercurv.  6.
 Silver.   7.  Gold.   8.  Platina.  9.' Iron.
 10. Copper.
           Order 10.  Pyrites.
   Genera.  1. Nickel-pyrites.  2. #-senic
 pyrites. 3. Cobalt-pyrites.  4. Iron-pyrites.
 5. Copper-pyrites.
           Order 11.   Glance,
   Genera.  1.  Copper-glance.  2.  Silver-
 glance.  3.  Lead-glance.  4. Tellurium-
 glance. 5. Molybdena-glance.  6. Bismuth-
glance. 7. Antimony-glance.  8. Melane-
 glance (black).
           Order 12.   Blende.
  Genera.  1.  Glance-blende.  2. Garnet-
 blende. 3. Purple-blende  4. Ruby-blende.
           Order 13.  Sulphur.
  1. Sulphur.
      Class  III.   Order  1.  Resin. 
MON
MOR
   Genus.  Melichrone-resin (honey-colour-
 ed).
             Order 2.   Coal.
   Genus.  Mineral-coal.

   Such are the Genera of Professor Mohs.
 I would willingly have introduced a view of
 the species; but his symbols of their crystal-
 line structure  and forms  would require a
 detailed explanation, inconsistent with the
 limits of this work.  An account of his new
 system of crystallography is given by one of
 his  pupils  in the 3d vol. ofthe Edin. Phil.
 Journal.   But  the Professor promises soon
 to publish that system himself; which»if we
 may judge from the luminous exposition of
 the characteristic of his Natural  H.story
 System, recently published, will be an im-
 mense acquisition to mineralogical science.*
   * Mineral  Caoutchouc    See  Caout-
 chouc*
   * Mineral  Charcoal.   See Charcoal
 (Mineral).*
   * Mineral Oil.  See Petroleum.*
   * Mineral Pitch.   See Bitumen.*
   Mimfralizer.   Metallic substances are
 said to be mineralized, when  deprived  of
 their usual properties by combination with
 some other substance.
   Minium.  Red oxide of lead.
   Mirrors.  See Speculum ; also Silver-
 inr.
   * Mispickel. Common arsenical pyrites.*
   * Mocha-stone.   See Agate.*
 ~ * Moltbdate of Lead.   See Ores  of
 ^■ad.*
JPmolybdenfm:.  A metal which has not yet
 been reduced into masses of any magnitude;
 but has been obtained only in small separate
 globules, in a blackish brilliant mass.  This
 may be effected by making its acid into a
 paste with oil,  bedding it in charcoal in a
 crucible, and exposing it to an intense heat.
 The globules are gray, brittle, and extreme-
 ly infusible.  By heat it is converted into a
 white oxide, which rises in brilliant needle-
 formed flowers, like those of antimony.
 Nitric acid readily oxidizes and acidifies the
 metal.  Nitre detonates with it, and the re-
 maining alkali  combines with its oxide.
   Molybdenum unites  with several of the
 metals, and  forms  brittle  or friable com-
 pounds.  No acid acts on it but the nitric
 and nitromuriatic.  Several acids act on its
 oxide, and afford blue solutions.'  See Acid
 (Molybdic).
  *  The sp. gr. of molybdenum is  8.611.
 When dry moly bdate of ammonia is ignited
 in a crucible with charcoal powder, it is con-
 Verted into the brown oxide of the  metal.
 This has a crystallized appearance, a copper-
 brown  colour,  and a sp. gr. of 5.66.   It
 does not form salts  with acids.  The deu-
 toxide is molybdous acid, which see,*
  *  Montmartrite. Its colour is yellowish;
 it occurs massive, but never crystallized.   It
 is soft.  It effervesces with nitric acid.  It
 is a compound of 83 sulphate of lime, and
 17  carbonate of lime,  which is found at
 Montmartre, near Paris.   It  stands ,the
 weather,  which common gypsum does not
 bear.*
  * Moonstone.  A variety of Adularia.*
  * Moor-coal.  See Coal.*
  * Morass-ore.  Bog-iron ore.*
  • Moroxylic Acid. See Acid  (Moroxy-
 lic).*
  * Morphia.   A  new  vegetable  alkali,
 extracted from opium, of which it constitutes
 the narcotic principle.  It was first obtained
 pure, by M. Serturner, about the year 1817.
  Two  somewhat different  processes  for
 procuring it, have been given by M. Robi-
 quet, and M. Choulant.
  According to the former, concentrated
 infusion of opium is to  be boiled  with a
 small quantity of common  magnesia for a
 quarter of an hour.  A considerable  quanti-
 ty of a grayish deposite falls.  This is to be
 washed on a filter with cold water, and, when
 dry, acted on by weak alcohol for some time,
 at a temperature beneath  ebullition.  In this
 way very little morphia,  but a great quan-
 tity of colouring matter, is separated.  The
 acid matter is then to be drained on  a filter)
 washed  with a  little  cold alcohol,  and
 afterwards boiled with a large quantity of
 highly rectified alcohol.  This liquid being
 filtered while hot, on cooling it deposites the-
 morphia in crystals, and very little coloured.
 The solution in alcohol and crystallization
 being repeated two or three times,  colour-
 less morphia is obtained.
  The theory of this process is the  follow-
 ing:—Opium contains a meconiate of mor-
 phia.  The magnesia combines with the me-
 conic acid, and the morphia is displaced.
  Choulant directs us to concentrate a dilute
 watery infusion of opium, and leave it at rest
 till  it spontaneously let fall its sulphate of
 lime in minute crystals.   Evaporate  to dry-
 ness ; redissolve in a little water, and throw-
 down any remaining lime and  sulphuric
 acid, by the cautious addition, first of oxalate
 of ammonia, and then of muriate of barytes.
 Dilute the liquid with a large body of water,
 and add caustic ammonia to it, as long as any
 precipitate falls.  Dissolve this in vinegar,
 and throw it down again with ammonia. Di-
 gest on the precipitate about twice its weight
 of sulphuric ether, and  throw the  whole
 upon a filter.  The dry powder is to be di-
 gested three times in caustic ammonia, and
 as often in  cold  alcohol.  The remaining
  Eowder being dissolved in twelve ounces of
  oiling alcohol, and the filtered hot solution
being set aside  for 18 hours, deposites co-
lourless transparent crystals, consisting of
double  pyramids.   By'concentrating  the
supernatent alcoholic solution, more crystals
may be obtained.
  Dr. Thomson directs us to pour caustic 
MOR                                 MOT
ammonia into a strong infusion of opium,
and to separate the brownish-white precipi-
tate by the filter; to evaporate the infusion
to about one-sixth of its volume, and mix the
concentrated liquid with more ammonia. A
new deposite of impure morphia is obtained.
Let the whole ofthe deposites be collected
on the filter, and washed  with cold water.
When well drained, pour a little alcohol on
it, and let the alcoholic liquid pass through
the filter   It will carry off a good deal of
the colouring matter,  and  very little of the
morphia.  " Dissolve  the  impure  morphia
thus obtained, in ace' ic acid, and mix the so-
lution, which has a very deep brown colour,
with  a  sufficient quantity of ivory-black.
This mixture is to be frequently agitated for
24 hours,  and  ihc-n thrown on the  filter.
The liquid passes through quite colourless.
If ammonia be now dropped into it, pure
morphia falls in the state of a white powder.
If we dissolve  this precipitate in alcohol,
and evaporate that liquid slowly, we obtain
the morphia, in pretty regular ci-  stals.  It
is perfectly white, has  a pearly lustre, is des-
titute of smell, but has an intensely bitter
taste, and the shape ofthe  crystals in all my
trials, was a four-sided rectangular prism."
Annals of Phil. June  1820.  On the  above
process I have only to  remark, that the ace-
tic  solution  must contain a  good deal of
phosphate  of lime, derived from the ivory-
black ; and that therefore those who have
used  that precipitate  for morphia in medi-
cine, have  been disappointed. The  subse-
quent solution in alcohol, however, and crys-
tallization, render it pure.
   M. Choulant says,  it crystallizes in  dou-
ble four-sided  pyramids,  whose  bases are
squares or rectangles. Sometimes in prisms
with trapezoidal bases.
   It dissolves in 82 times  its weight of boil-
ing water, and the solution on cooling de-
posites regular, colourless transparent crys-
tals.  It is soluble in  36 times its weight of
boiling alcohol, and in 42 times its weight of
 cold alcohol, of 0.92.  It  dissolves in eight
 times its  weight of  sulphuric ether.   All
these solutions change the infusion of brazil-
 wood to violet, and the tincture of rhubarb
 to brown.   The saturated  alcoholic  and
 ethereous solutions,  when  rubbed on the
 skin, leave a red mark.
   Sulphate of morphiacrystallizes in prisms,
 which dissolve in twice their weight of dis-
 tilled water.   They are composed of
            Acid,     22    5.00
            Morphia,  40    9.09
            Water,   38

                   100

   Nitrate  of  morphia  yields needle-form
  crystals in  stars, which  are soluble in  1$
  times  their weight of distilled water.  Its
  constituents are,
          Acid,    20     6.75
          Morphia, 36    12.15
          Mater,   44

                  100

  Muriate of morphia, is  in feather-shaped
crystals, and needles.   It is soluble in  101
times its weight of distilled water. Its con-
stituents are,

          Acid,    35   4.625
          Morphia, 41    5.132
          Water,  24

                  100

  The acetate crystallizes  in needles ; the
tartrate in prisms; and the carbonate in
short prisms.  Dr. Thomson states the ulti-
mate constituents of morphia to be,

          Hydrogen, 0.0555
          Carbon,   0.4528
          Oxygen,   0.4917
                     1.0000

from the analysis of one grain, by ignited
peroxide of copper.  He imagines the atom
to be either 40.25, or  20.125.  The former
number approaches to that of Pelletier  and
Caventou ;  the latter  is much greater than
any of Choulant's, deduced from the  above
saline  combinations, the mean  of which*
gives about 8.25.                      jH
  Morphia  acts with great energy on  trn^
animal economy.   A grain and a half taken
at three different times, produced such vio-
lent s\ mptoms upon three young men of 17
years  of age,  that  Serturner was alarmed,
lest the consequences should  have proved
fatal..
   Morphia, according  to its  discoverer,
melts in  a gentle heat; and in that state has
very  much the appearance of melted sul-
phur.  On cooling, it again crystallizes.  It
burns easily;  and when heated in close ves-
sels, leaves a  solid, resinous, black matter,
having a peculiar smell.*
   * Mortar Ckif.nt.  A mixture of lime,
and siliceous  sand, used in masonry for ce-
menting together the stones and bricks of a
building.  The most precise ideas which
we have on this subject, were given by Sir
H. Davy in his Agric. Chem.  See Limk.*
   * Mosaic Gold.  See Auhum  Musivum.*
   * Mothir of Pkahl shells are composed
of alternate layers of coagulated albumen
and carbonate of lime, in the proportion, by
 Mr. Hatchett, of 24 ofthe former and 76 of
the latter, in 100 parts.*
   Mother  Water.  When  sea-water or
 any other solution containing  various salts,
 is evaporated, and the crystals taken  out;
 there always  remains a fluid containing de- 
NAP                                 NEE
liquescent  salts, and the impurities, if pre-
sent.   This is called the mother water.
  Mould.  See Soil, Manure, and Analy-
sis (Vegetable).
  * Mountain Blue. Malaehite; carbonate
of copper.*
  ♦Mountain Cork and Mountain Leath-
er.   See Asbestus.*
  * Mountain Green.- Common copper
green; a carbonate of copper.*
  * Mo ntain or  Rock Wood.   See As-
BESTfS.*
  * Mountain  Soap.  Colour pale brown-
ish-black.  Massive.   Dull.  Fracture fine
earthy.  Opaque.  Streak shining. Writes,
but does not soil.  Soft.  Sectile.  Easily
frangible.  Adheres strongly to the tongue.
Feels very  greasy.  It is light, bordering on
rather heavy. It occurs in trap-rocks in the
island of Skyc. It is used in crayon-painting.*
  * MaciLAGE.    An  aqueous solution of
gum.*
  Mccrs.  This, according to Dr. Bostock,
is one of the primary animal fluids, perfect-
ly distinct from gelatin.
  The subacetate of lead  does not affect
gelatin;  on the other hand, tannin, which is
a delicate  test of gelatin,  does not affect
mucus.  Both these reagents,   however,
precipitate albumen; but the oxymuriate
of mercury, which will indicate the pre-
sence of albumen dissolved in 2000 parts of
water, precipitates neither mucus nor gela-
tin.  Thus we have three distinct and deli-
  te tests for these three  different princi-
«
  Gum  appears to  resemble mucus in its
properties.  One grain of gum-arabic, dis-
solved in 200 of water, was not affected by
oxymuriate of mercury, or by tannin, but
was immediately precipitated by subacetate
of lead.
  Muffle.  A small earthen oven, made
and sold by the crucible manufacturers.   It
is to be  fixed in a furnace, and is useful for
cupellation, and other processes which  de-
mand access of air.
  * Muriacite.  Gypsum.*
  * Muriatic Acu».  See Acid (Muriatic).*
  * Mcuicalcitk.   Rhomb-spar.*
  * Muscles of Avimai.s.   See Fibrin and
Flesh.*
  * Muscovy Glass.   Mica.*
  * Mushrooms   See Boletus.*
  *MrssrrE.   Diopside.*
  * Must.  The juice of grape, composed
of water, sugar, jelly, gluten, and bitartrate
of potash.  From a French  wine  pint of
must, the Marquis de Bullion extracted half
an ounce of sugar,  and  1-16th of an ounce
of tartar.  Proust says, the muscadine grape
contains about 30 per cent of a peculiar spe-
cies  of  sugar.   By  fermentation, it forms
wine.*
   * MyrticiN. The ingredient of wax which
remains after  digestion with alcohol.   !t is
insoluble likewise in water and ether;  but
very soluble in fixed and volatile oils.  Its
melting point  is about 120°.  Sp. gr. 0.90.
Its consistence is waxy.*
  * Mtrrh.   A gurr.-resin, which consists,
according to Braconnot,  of
Resin, containing some volatile oil,   33.68
Gum,    -.»...      66.32

                                 100.00
N
 *VTACR1TE.  SeeTALciTE.*
  i. il   * Nadelstein.  Rutile.*
   *Naiis  consist  of coagulated albumen,
 with a little phosphate of lime.*
   Nankin Dye. See Iron, towards the end.
   * Naphtha. A native combustible liquid,
 of a yellowish-white colour; perfectly fluid
 and "shining.  It feels greasy, exhales an
 agreeable bituminous smell, and has a spe-
 cific gravity of about 0.7.  It takes fire on
 the approach of flame, affording a bright
 white light.    It  occurs  in considerable
 springs on the shores ofthe Caspian Sea, in
 Sicily and  Italy.  It is used instead of oil,
 and differs from  the petroleum obtained by
 distilling coal tar, only by its greater purity
 and lightness.  By  Dr  Thomson's recent
 analysis of a specimen of naphtha from Per-
 sia, whose  sp. gr.  was 0.753, and boiling
 point 320°, it appears to be composed of
 carbon 82.2-+- hydrogen 14.8, with perhaps
a little azote.*
  Naples Yellow. According to Professor
Beckmann, this colour is prepared by cal-
cining lead with  antimony and potash in a
reverberatory furnace.
  * Natkox.  Native carbonate  of soda, of
which there are two kinds, the common and
radiated.  See Soiia.*
  ♦Natrolite.   A sub-species of prismatic
zeolite or  mesotype.    Colour  yellowish.
Massive,  in plates, and ren.form.  Seldom
crystallized.  Crystals  acicular.   Lustre
glistening,  pearly.  Translucent on  the
edges.   Sp. gr. 2.2. Before the  blow-pipe,
it becomes first black, then red, intumesces,
and melts into a  white compact glass.   Its
constituents are,  silica 48.0, alumina 24.25,
natron, 16.5, oxide of iron 1.75,  and water
9   It occurs in chalkstone  porphyry in
Wurtemherg and Bohemia, and in the trap-
tuff'hill named the Bin, behind Bruntisland
in Scotland*.
  * Needle Ona  Acicular bismuth-glance.* 
NIC                                   NIC
   * Nesdle Zeolite. Colour grayish-white.
 Massive; in distinct concretions; and crys-
 tallized in acicular  rectangular four-sided
 prisms, variously acuminated and truncated.
 The lateral planes are longitudinally streak-
 ed.   Glistening, inclining to pearly. Cleav-
 age twofold,  in the direction of the lateral
 plane of the prism.  Translucent.  Refracts
 double.  As hard as apatite  Brittle.  Sp.
 gr 2.3. It intumesces before the blow-pipe,
 and forms a  jelly with acids    It becomes
 electric by heating, and retains this property
 some time after it has cooled  The free ex-
 tremity ofthe crystal, with the acumination,
 shows positive, and the attached end nega-
 tive electricity.  Its constituents are, sihca
 50.24, alumina 29.3,  lime 9.46.  water 10. It
 occurs in secondary  trap-rocks near the vil-
 lage of Old Kiipatrick in Scotland.*
   * Nephehne.  Rhomboidal feldspar.  Co-
 lour white.  Massive and crystallized.  The
 primitive form is a di-rhomboid of 152p 44',
 and 56° 15'.   The secondary forms are, a
 perfect equiangular  six-sided  prism;  the
 same truncated on the terminal edges; and
 a  thick  six-sided table, with  the lateral
 edges all truncated.  The crystals form dru-
 ses.   Lustre splendent, vitreous. Cleavage
 fourfold.  Fracture  conchoidal.  Translu-
 cent and transparent.  As hard as feldspar.
 Sp.  gr. 2.6 to 1.7.   It melts with difficulty
 before the blow-pipe.  Its constituents are,
 silica 46, alumina 49, lime 2, oxide of iron 1.
 It occurs in drusy cavities, along with cey-
 lanite, vesuvian and meionite,  at Monte
 Somma, near Naples, in drusy cavities, in
 granular limestone.*
      •  hrite.  Of which mineral there are
 two kinds; common nephrite and axe-stone.
   Common nephrite.    Colour  leek-green.
 Massive and in rolled pieces. Dull.  Frac-
 ture coarse splintery.  Translucent.  Nearly
 as hard as rock-crystal.   Difficultly frangi-
 ble.   Feels rather  greasy.   Rather brittle.
 Sp. gr. 3.  It melts before the blow-pipe into
 a white enamel.  Its constituents are, silica
 50.5,  magnesia 31, alumina 10, iron  5.5,
 chrome 0 05, water 2.75. Nephrite occurs
in granite and gneiss, in Switzerland; and in
 veins ,.hat traverse primitive greenstone in
 the Hartz.  The most beautiful  come from
 Persia and Egypt.  The South American
 variety is called Amazon-stone,  from its lo-
 cality.*  See Axi.-Si'Onk.
  * Nerium Ti.mctouium.  A tree growing
 in Hindostan, which, according to Dr. Rox-
burgh, affords indigo.*
  •Neutralization.  When acid and alka-
 line  matter are  combined in such  propor-
tions  that the compound does not change
 the colour of litmus or violets, they are said
to be neutralized.*
  Nickel is a metal of great hardness, of a
 uniform texture, and of a colour between
 silver and tin  ; very difficult to be purified,
 and magnetical.  It even acquires  polarity
 by the touch.   It is malleable, both cold
 and red-hot; and is scarcely more fusible
 than  manganese.  Its  oxides, when pure,
 are reducible by a sufficient heat without
 combustible  matter;  and it is little more
 tarnished by heating in contact with air,
 than platina,  gold, and silver.  Its specific
 gravity when cast, is 8.279; when forged,
 8.666.
   Nickel is commonly obtained from its sul-
 phuret, the kupfernickel ofthe Germans, in
 which it is generally mixed also with arsenic,
 iron,  and cobalt.  This is first roasted, to
 drive off the sulphur and arsenic, then mix-
 ed with two parts of black flux,  put into  a
 crucible, covered with muriate of soda, and
 heated in a forge furnace.   The  metal thus
 obtained, which is still very impure, must be
 dissolved in dilute nitric acid, and then eva-
 porated to dryness; and after this process
 has been repeated three or four times, the
 residuum must  be dissolved  in a  solution of
 ammonia, perfectly free from carbonic acid.
 Being again evaporated to dryness, it is now
 to be well mixed with two or three parts of
 black flux, and  exposed to a violent heat in
 a crucible for half an hour or more.
   According to Richter,  the oxide is more
 easily reduced,  by moistening with a little
 oil.  Thenard advises  to pour chloride of
 lime on the oxide of nickel, and shake them
 well together, before the ammonia is added;
 as thus the oxides of cobalt and iron, if pre-
 sent, will be so much saturated with oxygen,
as to be insoluble in the ammonia, and coum
sequently may be separated.            fl
 ' M. Chenevix observed, that a very sm;SI
portion of arsenic prevents nickel from being
affected by the magnet.   Richter found the
same. When it is not attractible,  therefore,
 we may be pretty certain that this is present.
 To separate the arsenic, M. Chenevix boiled
the compound in nitric acid,  till the nickel
 was converted into an arseniate ; decompos-
 ed this by nitrate of lead, and evaporated the
 liquor, not quite to dryness.  He then pour-
 ed in alcohol, which dissolved only the ni-
trate  of nickel.  The  alcohol  being  de-
 canted and evaporated, he redissolved the
 nitrate in water, and precipitated  by potash.
 The precipitate, well washed and dried, he
 reduced  in a Hessian  crucible lined with
 lampblack, and found it to bo  perfectly
 magnetic; but this property was destroyed
 again, by alloying the metal with a small
 portion  of arsenic.   Alloying it with cop-
 per weakens this property.
  ♦There are two oxides of  nickel; the
dark ash-gray, and the black.  If potash be
added to the  solution ofthe nitrate or sul-
phate, and the precipitate dried,  we obtain
tfie protoxide.   It may be  regarded as a
compound  of about  100 metal with 28 of
oxygen; and the prime  equivalent of the
metal will  become  3.6, while that of the
 protoxide will be  4.6.   The preoxide was 
NIT                                   MIT
formed  by Thenard,  by passing chlorine
through the protoxide diffused in water. A
black insoluble  peroxide remains  at  the
bottom.
  Little is known of the chloride,  iodide,
sulphuret, or phosphuret of this metal.  A
compound, resembling  meteoric iron,  has
been made, by fusing together about 5 or 10
parts of nickel with 95 or 90 of iron.  The
meteoric iron from Baffin's Bay contains 3
per cent of nickel; the Siberian contains 10
per cent, by  Mr. Children's accurate analy-
sis.—See Journal of Science, vol. ix.
  The salts of nickel  possess the following
general characters.  They have usually a
green colour, and yield  a white precipitate
with ferroprussiate of potash.  Ammonia
dissolves the oxide of nickel.  Sulphuretted
hydrogen and infusion of galls occasion no
predpitate.  The hvdrosulphuret of potash
throws  down a  black precipitate.   Their
composition  has been very imperfectly as-
certained.*
  The sulphuric and muriatic acids have
Bttle  action  upon nickel.  The nitric  and
nitro-muriatic are  its  most appropriate sol-
vents.  The  nitric solution is of a fine grass-
green colour. Carbonate of potash throws
down from it a pale apple-green precipitate,
which, when well washed and dried, is very-
light.  One part of metal gives 2.927 of this
precipitate, which by exposure to a white
heatbecomesblackish-gray, barely inclining
to green,  and weighing only  1.285.   By
  •ntinuing the fire it is reduced
  When ammonia is  added  in excess to a
nitric solution of nickel,  a blue precipitate is
formed, which changes  to a purple-red in a
few hours, and  is converted to an  apple-
green by an acid. If the precipitate retain
its blue colour, copper is present.
  * Nicotin.  A  peculiar principle  obtain-
ed by Vauquelin from tobacco.  It is colour-
less, and has the  peculiar taste and smell of
the plant.  It dissolves both in water and
alcohol; is volatile, poisonous, and predpi-
table  from its solutions by tincture of galls.
—Ann  de Chimie, torn, lxxi.*
  ♦Nigiune.  An ore of titanium.*
  Nihil Albtm.   A  name formerly given
to the flowers or white oxide of zinc.
  * Nitrates.   Compounds  of nitric  acid
with the salifiable bases.*
  Nitre.  The common name of the nitrate
•f potash.  See Acm (Nithic).*
  * Nitrogen, or Azote, an imp; rtant ele-
mentary, or undecompounded principle. As
it constitutes four-fifths ofthe volume of at-
mospheric air, the readiest mode of procur-
ing azote, is to abstract  its oxygenous asso-
ciate, by the combustion of phosphorus, or
hydrogen. It may also be obtained from ani-
ana! matters,  subjected  in a glass retort to
the action of nitric acid,  diluted with 8 or 10
times its weight of water.
  Azote possesses all the physical properties
   Vol. U.
of air.  It extinguishes flame andanimal life.
It is absorbable  by  about lou volumes of
water.   Its spec, gravity  is 0.9722.   100
cubic inches  weigh 2i».65  grains.  It has
neither taste  nor smell.  It unites with oxy-
gen in  four proportions,  forming four im-
portant compounds.  These are
  1.  Protoxide of azote, or nitrous oxide.
  2. Deutoxide of azote, nitrous gas, or ni-
tric oxide.
  3.  Nitrous acid.
  4.  Nitric acid.
  1.  Nitrous oxide, or protoxide of azote, was
discovered hy Dr. Priestley in 1772, but was
first accurately investigated by Sir H.  Davy
in 1799.  The best mode of procuring it, is
to expose the salt called nitrate of ammonia,
to the flame of an Argand lamp, in a glass
retort.  When the temperature reaches400°
F a whitish cloud will begin to project itself
into the neck ot  the retort, accompanied by
the copious evolution of gas, which must
be collected over mercury for accurate re-
searches, but for common experiments :.ay
be received over water.   It has all the phy-
sical properties of air. It has a sweet taste,
a faint agreeable odour,  and is condensible
by about its own volume of water, previous-
ly deprived of its atmospheric ,air.  This
property enables us to determine the purity
of nitrous oxide.  A taper plunged into this
gas,  burns with great brilliancy ; the  flame
being surrounded with a bluish halo.  But
phosphorus may be melted and sublimed in
it, without taking fire.  When this combus-
tible is introduced into it, in a state of vivid
combustion,  the brilliancy of the flame is
greatly increased.   Sulphur and most other-
combustible bodies, require a higher degree
of heat for their combustion in it, than in
either oxygen or common air.   This may be
attributed to the counteracting affinity ofthe
intimately combined azote.  Its sp. grav. is
1.5277.  100 cubic inches weigh 46.6 gr.
It is respirable, but not fitted to support life.
Sir H.  Davy first showed, that by breathing
a few quarts of it,  contained in a silk bag,
for two or three minutes, effects analogous
to those occasioned by drinking fermented
liquors, were produced.   Individuals, who
differ in temperament, are, however,  as we
might expect, differently affected.
  Sir H. Davy  describes the effect it had
upon him, as follows :—" Having previously
closed my nostrils, and exhausted my lungs,
I breathed four quarts of nitrous oxide from
and into a silk bag. The first feelings were
similar to those produced in the last experi-
ment,  (giddiness); but in less than half a
minute, the respiration being continued, they
diminished gradually, and were succeeded
by a sensation analogous to gentle pressure
on all the muscles, attended  by an highly
pleasurable  thrilling, particularly  in  the
chest and the  extremities.   The objects
amird me became dazzling, and my hearing
                  25 
NIT
NIT
 more acute. _ Towards the last inspiration
 the thrilling increased, the sense of muscu-
 lar power became greater, and at last an ir-
 resistible propensity to action was indulged
 in.  I recollected but indistinctly what fol-
 lowed; I know that my motions were vari-
 ous and violent.
   " These effects very soon ceased after res-
 piration.  In ten minutes I  had recovered
 my natural state of mind.  The thrilling in
 the extremities continued lbnger than the
 Other sensations."
   " The gas has been breathed by a very
 great number of persons, and almost  every
 one has  observed the  same things.   On
 some few,  indeed, it has no effect  what
 ever, and on others the effects are always
 painful.
   " Mr. J. W. Tobin,  (after the first imper-
 fect trials), when the  air was pure, experi-
 enced  sometimes sublime emotions  with
 tranquil gestures, sometimes violent mus-
 cular action, with sensations indescribably
 exquisite; no subsequent debility—no ex-
 haustion ;—his trials have been very nume-
 rous.  Of late he has  only felt sedate plea-
 sure.  In Sir H. Davy the effect is not di-
 minished.
   "  Mr. jTames  Thomson.    Involuntary,
 laughter,  thrilling in his  toes and  fingers,
 exquisite  sensations of pleasure   A  pain
 in the back and  knees, occasioned by fa-
 tigue the day before, recurred a few minutes
 afterwards. A similar observation, we thi nk,
 we have made on others; and we impute it
 to the undoubted  power of the gas  to in-
 crease  the  sensibility or nervous power,
 beyond any  other agent, and probably in a
 peculiar manner.
   " Mr. Thomas Pople.   At first  unplea-
 santfeelings of tension; afterwards agreea-
 ble luxurious languor, with suspension of
 muscular  power;  lastly, powers increased
 both of body and mind.
   " Mr. Stephen Hammick, surgeon of the
 Royal Hospital, Plymouth. In a small dose,
 yawning and languor.  It should be observ-
 ed that the  first sensation has often  been
 disagreeable, as giddiness; and a few per-
 sons, previously apprehensive, have left oft'
 inhaling as soon as they felt this.  Two lar-
 ger doses produced a glow,  unrcstrainable
 tendency  to muscular action, high spirits
 and more vivid ideas.   A bag of common
 air was  first given  to Mr. Hammick, and
 he observed that it  produced no effect.
 The same  precaution against  the  delu-
sions of imagination was of course frequently
taken.
   " Mr.  Robert  Southey could not distin-
 guish between the first effects and an ap-
 prehension  of which  he was  unable to di-
 vest himself.  His first definite sensations
 were, a fullness and dizziness in the head,
 such as  to induce  a fear  of  falling.  This
was 6U0Cceded by a laugh whidi was invol-
 untary, but highly pleasurable, accomp*
 nied with a peculiar thrilling in the extre-
 mities, a sensation perfectly new and de-
 lightful.  Formany hours after this experi-
 ment, he imagined that his taste and smell
 were more acute, and is certain that he felt
 unusually strong and cheerful.   I n a second
 experiment, he  felt pleasure still superior,
 and has once poetically remarked, that  he
 supposes the atmosphere of the highest of
 all possible heavens to be composed of this
 gas.
   " Robert  Kinglake, M  I).    Additional
 freedom and power of respiration, succeed-
 ed by an almost delirious, but highly plea-
 surable sensation in the head, which became
 universal, with increased tone of the mut-
 cles.  At last, an intoxicating placidity ab-
 sorbed for five minutes all voluntary power,
 and left  a. cheerfulness and alacrity for se-
 veral hours.  A second stronger dose pro-
 duced a perfect trance for about a minute;
 then a glow pervaded the system  The
 permanent effects were an invigorated feel-
 ing of vital  power, and  improved spirits.
 By both trials, particularly by the former,
 old rheumatic feelings  seemed  to be re-
 vived for the moment.
   "  Mr. Wedgwood breathed atmospheric
 air first, without knowing it was so.   He de-
 clared it to have no effect, which confirmed
 him in his disbelief of the power of the gas.
 After breathing this some time, however,
 he threw the bag from him, kept breathing
 on laboriously with an open mouth, holding
 his nose with his left hand, without povv^B
 to take it away, though aware of the ludF
 crousness of his situation;  all  his  muscles
 seemed to be  thrown into vibrating mo-
 tions -,  he had a violent inclination to make
 antic gestures, seemed lighter than the at-
 mosphere, and as if about to mount.  Be-
 fore the experiment,  he was a good deal
 fatigued after a long ride, of which he per-
 manently lost all  sense.  In a  second ex-
 periment, nearly the same effect, but ivitb
 less pleasure.  In  a third,  much  greater
 pleasure."  Res. on. nit. ox.
   I  have often  verified these pleasurable
 effects, on myself and my pupils.  The caus-
 es of failure, in most cases, I believe to be,
 impure gas, a narrow tube or stop-cock, or
 precipitate breathing from fear.  If a little
 sulphate or muriate be mixed with the ni-
 trate of ammonia, it will not yield an intox-
 icating gas.  1 use a pretty w ide glass tube^
 fixed to the mouth of a large bladder.
   I find that mice, introduced into a jar con-
 taining nitrous oxide, die almost instantly;
 while in azote, hydrogen, and carbonic acid,
 they struggle for a little while.
   This gaseous compound may be analyzed
 by the combustion of hydrogen, carbon, or
 phosphorus in it.  If we mix 100 volumes
 of nitrous oxide with 100 of hydrogen; and
detonate the mixture in an explosive eudio- 
NIT
NIT
meter, nothing will remain but 100 mea-
sures of azote.  Hence 50 measures of'oxy-
gen, the equivalent quantity of 100 of hy-
drogen, must have existed in the oxide.   It
therefore consists  of 100 measures of azote
4- 50 of oxygen,  condensed by reciprocal
attraction, into only  100 measures.
Now 100 voL of azote, weigh       0.9722
                       1.1111
     50     of oxygen,------ = 0.5555
                         2
                                  1.5277
This  synthetic sum exactly coincides with
the specific gravity of the compound.  It
is therefore composed by  weight of one
prime equivalent of azote, «= 1.75  63.64
           one of oxygen, = 1.00  36.36

                           2.75 100.00
The weight ofthe compound prime, is the
same with that of carbonic acid.
   Iron  wire  burns with  brilliancy  in the
above gas, but it is soon extinguished.
   2. Deutoxide of azote, or nitric oxide, was
first described by Dr. Priestley in 1772.  In-
to a  glass retort, containing copper turn-
ings,  pour nitric acid diluted with 6 or 8
times its  quantity of  water, and apply a
gentle heat.   A gas comes  over,  which
may be collected  over water ; but  for ex-
act experiments, it should be received over
mercury.   Its sp. gr. is  1.0416.   100 cubic
inches  weigh  36.77 grains.   Water con-
denses only about  ■£§ of its volume of nitric
oxide.   But a solution of protosulphate  or
protomuriate of iron, absorbs it  very co-
piously,  forming a dark  coloured  liquid,
which is used for condensing oxygen, in the
eudiometer of Sir H. Davy.
  When a jar of nitric oxide is opened in the
atmosphere,  red fumes appear,  in  conse-
quence  of the absorption of oxygen, and
formation of nitrous acid.  When an animal
is made to inhale this gas,  it is instantly de-
stroyed by the formation of this  acid, and
condensation of the oxygen, in  its lungs.
When a burning taper is immersed  in this
gas, it is extinguished;  as well as the flame
of sulphur.  But inflamed phosphorus burns
in it with great splendour.  A mixture of
hydrogen gas and nitric oxide, burns with a
lambent green flame, but does not explode
by the  electric spark; though  Fourcroy
says  that  it  detonates on  being passed
through an ignited porcelain tube. The
pyrophorus  of  Homberg spontaneously
burns in it.
  It is decomposable by several ofthe me-
tals,  when they are heated in it, such  as
arsenic,  zinc, and potassium  in excess.   It
oxidizes them,  and affords half its volume
of azote.  Charcoal ignited in it, by a burn-
ing glass, produces half a  volume  of azote,
and half a volume of carbonic acid.  All
these  analytical experiments concur   to
show,  that nitric oxide consists of oxygen
and azote, in equal volumes.  Hence, if we
take the mean weight of a volume of each
gas, we shall have that ofthe gaseous com-
pound ; or, its sp. gr.
                   Sum.  Hf. sum orsp.gr.
 Azote,   09722 > 2              g
 Oxygen, 1.1111 5
   If we convert these into equivalent ratic-Sy
we shall have the gas composed of
       1 prime of azote = 1.75  46.66
       2 primes oxygen «■ 2.00  53.33

                             100.00
   When this deutoxide is  exposed at ordi-
nary temperatures,  to bodies which have a
strong attraction for oxygen,  such  as the
sulphites, protomuriate of tin, and the al-
kaline hydrosulphurets, two volumes of it
are converted  into  one volume ofthe pro-
toxide. We see here, that when one prime
of oxygen is abstracted, the remaining one
enters into  a denser state of union with
azote.
   For the habitudes of this gas with hydro-
gen, see Ammonia ;  and with oxygen, see
Eudiometer,  and  Nitric and  Nitrous
Acids.
   Azote combines with chlorine and iodine,
to form two very formidable compounds.
   1. The chloride of azote was discovered
about the beginning of 1812, by M. Dulong;
but its nature was first  investigated and as?
certained by Sir II  Davy.
   Put  into an  evaporating porcelain basin,
a solution of one part of nitrate or muriate
of ammonia in 10 of water, heated to about
100°, and invert into it a wide mouthed
bottle  filled with chlorine. As the  liquid
ascends by  the  condensation  of the gaSj
oily-looking drops  are seen floating oh its
surface, which collect together, and fall to
the bottom in large globules.  This is chlo-
ride of azote.   Ry putting a thin stratum of
common salt into the bottom ofthe basin,
we prevent the decomposition ofthe chlo-
ride of azote,  by the ammoniacal salt.  It
should be formed only in  very small quan-
tities.  The chloride of azote thus obtained, is
an oily-looking liquid; of a yellow colour;
and a very pungent intolerable odour, simi-
lar to that of chlorocarbonous acid.  Its sp.
gr. is 1.653.   When tepid water is poured
into a glass containing it, it expands into a
volume of elastic fluid, of an orange colour,
whi*h diminishes as it passes through the
water.
  "I attempted,"  says Sir H.  Davy, " to
collect the products ofthe explosion ofthe
new  substance, by applying the  heat of a
spirit-lamp to  a globule of it; confined in a
curved glass tube over water: a little gas
was at first extricated; but long before the
water had attained the temperature of ebul-
lition, a violent flash of light was perceived*
.with a  sharp  report; the tube  and glass 
NIT                                   NIT
were broken into small fragments, and I re-
ceived a severe wound in the transparent
cornea of the eye, which  has produced a
considerable inflammation  ofthe eye, and
obligjs me to make this communication by
an amanuensis.   This experiment proves
what extreme caution is necessary in operat-
ing on this substance ;  for the quantity  I
used was scarcely  as large as a grain of
mustard-seed."   Phil. Trail. 1813, part I.
It evaporates pretty rapidh in the air; and
in vacuo  it expands into a  vapour, which
still  possesses the power of exploding by
heat.  When it  is  cooled artificially in wa-
ter, or the ammoniacal  solution, to 40° F.,
the surrounding  fluid  congeals; but when
alone, it may be  surrounded  with a mixture
of ice and muriate of lime, without freezing.
  It gradually disappears in water, produc-
ing azote;  while the  water  becomes acid,
acquiring the taste and smell of a weak so-
lution of nitro-muriatic acid.
  With muriatic  and nitric  acids, it yields
azote;  and with dilute  sulphuric  acid, a
mixture  of azote and oxvgen.  In strong
solutions of ammonia it detonates,-  with
weak ones, it affords azote.
  H hen it  was exposed to pure mercury,
out of the contact of water, a white powder
(calomel)  and   azote  were the  results.
" Tne action of mercury on the compound,"
says Sir H.  " appeared to offer a  more cor-
rect and less dangerous mode of attempting
its analysis; but  on introducing two -rains,
under a glass tube  filled with mercury and
inverted, a violent detonation occurred, by
which I was slightly wounded in the head
and hands,  and should have been severely
wounded, had  not  my eyes and face been
defended by a plate of glass, attached to a
proper cap; a precaution very necessary in
all investigations of this body."—Phil.Trans.
1813, part 2d.  In using smaller quantities,
and recently distilled mercury, he obtained
the results ofthe experiments, without any
violence of action.
  From his admirable experiments on the
analysis of this  formidable  substance, by
mercury, by  muriatic acid, and from the
discoloration of sulphate of indigo, we may
infer its composition to be
4 vol. of chlorine  = 10.     4 primes 18.0
1    of azote    ■=  0.9722  1         1.75
or very nearly 10 by weight of chlorine to 1
of azote.
  •A small globule of it,  thrown into a^lass
of olive oil, produced a most violent explo-
sion ; and  the  glass  though  strong, was
broken into fragments. Similar effects were
produced by its action on oil of turpentine
and naphtha. \\ hen it was thrown into ether
or alcohol, there  was a very slight action.
When a par icle  of it was  touched under
waler by a particle of phosphorus, a bril-
liant light was perceived under the  water,
and permanent ^as was disengaged, having
the characters of azote.
  When  quantities larger than a grain of
mustard-seed were  used for the  contact
with phosphorus, the explosion was always
so violent as to break the vessel  in  which
the experiment was  made.  On tinfoil and
zinc it exerted  no action; nor on sulphur
and resin.  But it detonated most violently
when thrown into a solution of phosphorus
in ether or alcohol.
  The mechanical force  of this compound
in detonation, seems superior to that of any
other known, not even excepting the am-
moniacal fulminating  silver.   The velocity
of its action appears to be likewise greater.
I touched a minute  globule of it, in a pla-
tina spoon resting on a  table, with a frag-
ment of phosphorus at the point  of a pen-
knife.  The  blade  was  instantly shivered
into fragments by the explosion.
  Messrs. Porret, Wilson, and Rupert Kirk,
brought 125 different substances in contact
with it.  The following were the  only ones
which caused it to explode :—
     Supersulphuretted hydrogen.
     Phosphorus.
     Phosphurct of lime.
     Phosphuretted camphor.
     Camphuretted oil.
     Ph sphuretted hydrogen gas.
     Caoutchouc.
     Myrrh.
     Pulm oil.
     Ambergris.
     W hale oil.
     Linseed oil.
    Olive oil.                          -*
    Sulphuretted oil.
    Oil of turpentine.
    ---- iar.
    ---- amber.
     ---- petroleum.
     ---- orange-peel.
     Naphtha.
     Soap of silver.
     ----— mercury.
     ------ copper.
     ------ lead.
     ------ manganese.
     Fused potash.
     Aqueous ammonia.
     Nitrous gas.—Nich. Journ. vol. 34.
  2. Iodide of azote.  Azote does not com-
bine directly with  iodine.   We obtain the
combination only by means of ammonia.  It
was discovered  by  M. Courtois,  and care-
fully examined  by  M. Colin.  When am-
moniacal gas is passed over iodine, a  viscid
shining liquid is immediately formed of a
brownish-black  colour,  which, in propor-
tion as it is saturated with ammonia, loses
its  lustre and viscosity.   No gas is disen-
gaged during the formation of this liquid,
W hich may  be called iodide of ammonia.  It
is not fulminating.   When dissolved in wa-
ter,  a part of the ammonia is decomposed;
its hydrogen forms hydriodic acid; and  itfl
azote combines with a portion of the iodine, 
NIT                                 NUX
»nd forms the fulminating powder.  We
mav obtain the iodide of azote directly, by
putting pulverulent  iodine  into common
water of ammonia.  This indeed is the best
way of preparing it; for the water is.not de-
composed, and seems to concur in the pro-
duction of this iodide, only by  determining
the formation of hydriodate of ammonia.
  The iodide of azote is  pulverulent, and
of a brownish-black  colour.   It detonates
from the smallest shock, and from heat, with
a feeble  violet  vapour.   When  properly
prepared, it often detonates spontaneously.
Hence, after the black powder is formed,
and the liquid ammonia decanted off', we
must leave  the  capsule containing it in
perfect repose.
   When this iodide is  put into potash  wa-
ter, azote is disengaged, and the same pro-
ducts  are obtained,  as  when iodine  is dis-
solved in that alkaline lixivium.  The  hy-
driodate of ammonia, which has the proper-
ty of dissolving a  great deal of iodine, gra-
dually decomposes the fulminating powder,
while azote is set  at liberty.  Water itself
has this property,  though in a much lower
degree. As the elements of iodide of azote
are so feebly united, it ought to be prepared
with great precautions, and* should not be
preserved.  In the act of transferring a lit-
tle of it from a platina capsule to a piece of
paper, the  whole exploded in my hands,
though the friction ofthe particles on each
other  was inappreciably small.
   Both  Sir H.  Davy  and M. Gay-Lussac
hrfcve exploded their iodide in glass  tubes,
and collected the results.  The latter states,
 " that if we decompose a gramme (15.444
grains) of the fulminating powder, we ob-
tain, at the temperature of" 32°, and under
the pressure of 30 inches  of mercury, a ga
seous  mixture  amounting to 0.1152 litre,
 (7.03 cubic inches), andcomposedof 0.C864
 ofthe vapour of iodine, and 0.0288 of azote."
 —Ann.  de  Chimie, xci.  Now 0.0864 is to
 0.0288 as 3 to 1 exactly.  Therefore the de-
 tonating powder consists cf
 3vols, oftheva.ofiod.=« 8.63x3= 25.89
 lvol. of       azote   -    - =  0.9722
 or reduced to the oxygen equivalent scale,
 it consists of
   3 primes of iodine  = 46.5      96.37
   1           azote =  1.75      3.63
                               100.00
  Azote has hitherto resisted all attempts
to decompose it.   Sir H. Davy volatilized
the highly combustible  metal potassium in
azote over mercury, and passed the voltaic
flame of 2000 double plates through  the
vapour, but the azote underwent no change.
He made also many other attempts to de-
compose it, but they were unsuccessful.
  In my experiments on the ammoniacal
salts, 1 found, that when  dry lime and mu-
riate of ammonia  were ignited together in
a Reaumur porcelain tube, connected with
water in a Woulfe's apparatus, a portion of
ammonia constantly disappeared, or was an-
nihilated, while  nothing  but water was ob-
tained to replace that loss.   " Ofthe tight-
ness ofthe apparatus I am well assured. In-
deed  I  have performed the experiment,
with a  continuous glass tube, sealed and
bent down  at one end like a retort, while
the other end was drawn into a  smal' tube,
which passed under ajar on the mercurial
pneumatic  shelf. The  middle  part was
 kept horizontal and artificially cooled.  The
sealed end  contained the mixture of lime
and sal ammoniac. A brush flame of a large
alcohol  blow-pipe was made to play very
gently on the end of the tube at first, but
afterwards so powerfully, as to keep  it ig-
nited for some  time.   The sal ammoniac
recovered, did not exceed three-fourths of
 that originally employed."  The sal ammo-
 niac was regenerated by  saturating the am-
 monia with  muriatic  acid, and cautious
 evaporation.  See Ann.  of Phil.  September
 1817.
   The strongest arguments for  the  com-
 pound nature of azote are derived from its
 slight tendency  to combination,  and from
 its being found abundantly in the organs of
 animals, which feed on  substances that do
 not contain it.
   Its uses in the economy of the  globe are
 little understood. This  is likewise favour-
 able to the  idea that the real chemical na-
 ture is  as yet unknown, and leads to the
 hope of its being decomposable.
   It would appear  that  the  atmospheric
 azote and  oxygen spontaneously combine
 in other proportions, under  certain circum-
 stances, in  natural  operations.   Thus we
 find, that mild calcareous or alkaline matter
 favours  the formation of  nitric acid, in cer-
 tain regions ofthe earth; and that they are
 essential to its production in our artificial ar-
 rangements, for forming nitre from decom-
 posing animal and vegetable substances.*
   Nitroi s  Acid.  See Acid (Niirous).
   Noble Mmms.  This absurd  name has
 been bestowed on the perfect metals, gold,
 silver, and platina.
   * NOVACULITE.  WHETSLATE.*
   * Nux Vomica.  See STaxcHBU.* 
OIL
OIL
O
 * /"hBSIDIAN.   Of this mineral there are
  \J two kinds, the translucent and trans-
 parent.
  1.  Translucent  obsidian.   Colour  velvet-
 black. Massive. Specular splendent. Frac-
 ture  perfect conchoidal.  Translucent,  or
 translucent on the edges. Hard. Very  brit-
 tle.   Easily frangible.  Streak gray. Sp. gr.
 2.37   It melts, or becomes spongy before
 the blow-pipe.  Its constituents are, silica
 78, alumina 10, lime 1, soda 1.6, potash  6,
 oxide of iron 1.— Vauq.  It occurs  in beds
 in porphyry, and various secondary  trap
 rocks in Iceland and Tokay.
  2.  Transparent. Colour duck-blue. Mas-
 sive and in brown grains.  Splendent. Frac-
 ture perfect conchoidal.  Perfectly transpa-
 rent.   Hard.   Brittle.   Sp.  gr.  2.36.   It
 melts more easily than the translucent obsi-
 dian,  and into a white muddy glass.  Its con-
 stituents are,  silica  81,  alumina 9.5, lime
 0.33,  oxide of iron 0.60, potash '2.7, soda 4.5,
 water 0.5.—Klaproth.  It occurs imbedded
 in pearl-stone  porphyry.  It is found  at
 Marekan, near  Ochotsk  in  Siberia, and in
 the Serro de las Novajas in Mexico.*
  • Ochre.  An ore of iron.*
  * Ochroits.  Cente.*
  * Octohedrite. Pyramidal titanium-ore.*
  * Oetites.  Clay-ironstone.*
  * Oil of Vitriol.  See Acin (Suiphu-
 bic).*
  Oil.  The distinctive characters of oil are
 inflammability,  insolubility in water,  and
fluidity, at least in a moderate temperature.
Oils are distinguished into fixed or fat  oils,
which do not rise  in distillation at the tem-
perature of boiling water; and volatile or es-
sential oils, which do rise at that temperature
with water, or under 320° by themselves.
  The volatile oil obtained by attenuating
 animal oil, by a number of successive distil-
 lations, is called Dipper's animal oil.
  Monnet asserts, that, by mixing acids with
animal oil, their rectification may be very
much-facilitated.
  The addition of a little ether,  before re-
 distillation of old essential oils, improves the
 flavour of the product.   See Elain and
 Acin  (Oleic.)
  * MM.  Gay-Lussac  and Thernard  ana-
 lyzed olive oil in 1808, by igniting a deter-
 minate quantity of it, mixed with chlorate of
 potash, and ascertaining the products; they
 found it to consist of
                 Carbon,    77.213
                 Hvdrogen, 13.360
                 Oxygen,     9.427
too.ooe
Or               t'irboii,   77.21.-!
ox. and hydr.  in the pro-)  io 712
portions for forming water, $
           Hydrogen excess, 12.075
   If the pernitrate of  mercury,  made by
dissolving 6 parts of mercury in 7.5 parts of
nitric acid, ot sp. gr. 1.36 at common tempe-
ratures.be mixed with olive oil, in thecoursc
of a few hours, the mixture, if kept cold, be-
comes solid; but if mixed with the oil of
grains,  it does not solidify. M. Pontet pro-
poses therefore this  substance as a test of
the purity or adulteration of olive oil; for the
resulting mixture, after standing 12 hours, is
more or less solid, as the  oil is more or les9
pure.  The nature of the white, hard, and
opaque mixture, formed by olive oil and the
nitrate of mercury, has not been ascertained,
See A<-id Muig.viiic, Elain, and Fat.*
   ♦Oil Gas.  It has been long known to
chemists,  that  wax,  oil, tallow, &c. when
passed through ignited tubes,  are resolved
into combustible  gaseous matter,  which
burns with a rich light.  Messrs.  Taylor and
Martincau have availed themselves skilfully
of this fact, and contrived an ingenious ap-
paratus for generating oil gas on the great
scale, as a substitute for candles, lamps, and
coal gas.  I shall insert here, a brief account
of their improvements.
   The advantages of oil gae, wheH contrasted
with c-ial gas,  are the following:—The ma-
terial from which it is produced containing
no sulphur or other matter by which the gas
is  contaminated, there are no objections to
its use on account  of the  suft'ocating smell
in close rooms.  It does no sort of injury to
furniture, books, plate, pictures, paint, &c.
All the costly  and offensive  operation of
purifying the  gas by lime, &c.  is totally
avoided when it is obtained from  oil.  No-
thing is contained in oil gas which can pos-
sibly injure the metal of which the convey-
ance pipes are  made.
   The economy of light from oil gas may be
judged of from the following table:—
 Argand burner oil gas, per hour,      $rf.
 Argand lamps spermaceti oil,     -   3d.
 Mould candles,     -     -       -   3$d.
 Wax candles,        -     -       -   lid.
   The oil gas has a material advantage over
coal gas,  from its peculiar richness in ole-
fiant gas, which renders so  small volume
necessary, that one cube foot of oil gas will
be found  to go as far  as four  of  coal gas.
This circumstance is of great importance, as
it  reduces in the same  proportion  the  size
of the  gasometers, which are  necessary to
contain it:  this is not only a great  saving of
expense  in fhe construction,  but i%  is « 
OIL
ONY
.material convenience, where room is li-
mitted.
   In the course of their first experiments,
Messrs. John  and Philip Taylor were sur-
prised to find, that the apparatus they em-
ployed gradually  lost its power of decom-
posing oil, and generating gas.  On investi-
gation, they discovered that the  metallic
retorts which had  originally decomposed
oil and produced  gas in abundance, ceased
in a very great degree to possess this power,
although no visible change had taken place
in them.
   The most perfect cleaning of the interior
of the retort did  not restore the effect, and
some alteration appears to be produced on
the iron by the action of the oil, at a high
temperature.
   Fortunately, the experiments on this sub-
ject led to  a most favourable result; for it
was found, that by introducing fragments of
brick  into the retorts, a great increase of
the decomposing power was obtained, and
the apparatus has been much improved by
a circumstance which at one time appeared
to threaten its success.
   A small portion of the oil introduced into
the retort, still passed off undecomposed,
and being changed into a volatile oil, it car-
ried with it a great portion of caloric, which
rendered the construction ofthe apparatus
more difficult than was at first anticipated;
but by the present arrangement of its parts,
this difficulty is fully provided for, and the
volatilized oil is  made to return into the oil
■reservoir, from whence it again passes into
the retort,  so that a total conversion of the
whole into gas is accomplished without trou-
ble, or the escape of any unpleasant smell.
   A general idea of the  process may be
formed from the following account of it;—
   A quantity  of oil is placed in an air-tight
vessel, in such a  manner, that it may flow
into retorts which are kept at a moderate
red heat; and in such proportions as  may
regulate the production of gas to a conveni-
ent rate; and it is provided, that this  rate
may be easily governed at the will of the
operator.
   'The oil, in its passage through the retorts,
is principally  decomposed,  and converted
into gas proper for illumination, having the
great  advantages of being  pure and  free
from sulphurous contamination, and of sup-
porting a very brilliant flame, with the ex-
penditure of very small quantities.
   Asa further precaution to purify the gas
from  oil,  which may be suspended in it in
the state of vapour", it is conveyed into a
wash vessel, where, by bubbling through
water, it is further  cooled and rendered fit
for use ; and passes by a proper pipe into a
gasometer,  from  which it  is suffered to
jiranch off in pipes in the usual-manner.
   The oil gas  which 1 have been accustom-
ed to make has only  a double illuminating
power, compared to good coal gas.—See &
drawing of an elegant apparatus, erected by
Messrs. P. and M. at the Apothecaries' Hall,
London, in the 15th number of the Journal
of Science and the Arts.*  f
  * Oisanite.  Pyramidal titanium-ore.*
  * Olefiant Gas.  A compound of  one
prime  of carbon and one  of hydrogen, to
which  I have given the name of Carburet-
ted Hydhooe.v,  to distinguish it from the
gas resulting from one prime of carbon and
two ot hy drogen, which 1 have called sub-
carburetted  hydrogen.*
  * Oleic Acid.  See Acid (Oleic).*
  Oleosaccharum.   This  name is given to
a mixture of oil and sugar, incorporated
with each  other, to render the oil more easi-
ly diffusible  in watery liquors.
  Oleum Vim.   bee Ether.
  Olibanum.  A gum-resin, the product of
the Juniperus  Lycia, Linn, brought from
Turkey and the  East Indies, usually in
drops or tears.   The best is of a yellowish-
white colour, solid, hard, and brittle; when
chewed for a little time, it renders the spit-
tle white,  and impresses an unpleasant bit-
terish taste; laid on burning coals, it yields
an agreeable smell.
  * Olive.ni ie.  An ore of copper.*
  * Olivine.  A sub-species of prismatic
chrysolite.  Its  colour is olive-green.  It
occurs massive and in  roundish  pieces.
Rarely crystallized in imbedded rectangular
four-sided prisms.   Lustre shining.   Clea-
vage, imperfect double.   Fracture,  smaii-
grained uneven.   Translucent.  Less hard
than chrysolite.  Brittle. Sp.  gr. 3.24.  With
borax  it  melts  into a dark green bead.  It
loses its colouring  iron in nitric  acid.  Its
constituents are, silica 50, magnesia 38.5,
lime 0.25, oxide of iron  12.   It occurs i*
basalt, greenstone, porphyry and lava, and
generally  accompanied with  augite.   It i«
found  in the Lotliians, Hebrides, north of
Ireland, Iceland, France, Bohemia, &c*
  * Ollaius Lapis.  See Potstone.*
  * Omfhacite. Colour  pale leck-green.
Massive, disseminated,  and in narrow  aadi-
ated concretions.   Lustre, glistening and
resinous.  Fracture, fine-grained uneven.
Feebly translucent.  As hard as feldspar.
Sp. gr. 3.3.   It occurs in primitive  rocks
with precious garnet, in  Carinthia.   Jt is a
variety of augite.*
   * 0.\yx.  Calcedony, in which there is
an alternation of white,  black,  and dark-
brown layers.*
  f 1 question the-  correctness of  these
statements concerning oil gas.  On account
of the sale of the coak, it has been found,
even in this country,  more profitable to
make gas from coal than tar.  Yet tar costs
only about  one-sixth of the price  of the
cheapest oil in our markejs. 
OPA
OPO
  • Opacity.  The faculty of obstructing
the passage of light.*
  * Opal.   A sub-species ofthe indivisible
quartz of Mohs.*
  Of opal there are seven kinds, according
to Professor Jameson.
  1. Precious opal.  Colour milk-white, in-
clining to blue.   It exhibits a beautiful play
of manv colours.   Massive, disseminated,
in  plates and  veins.   Lustre  splendent.
Fracture, perfect conchoidal.  Translucent,
or semi-transparent.  Semi-hard in  a  high
degree.  Brittle.   Uncommonly easily fran-
gible.   Sp. ?r. 2.1.  Before the blow-pipe it
whitens and becomes opaque, but does not
fuse.  Its constituents are silica 90, water
10.   It  occurs in  small veins  in  clay-por-
phyry, with semi-opal,  at Czscherwenitza,
in Upper Hungary ; and in trap  rocks, at
Sandy Brae, in the north of Ireland.  Some
of them  become transparent by immersion
in water; and are called oculus mundi, hy-
drophane, or changeable opal.
  2.  Common opal.   Colour  milk-white.
Massive, disseminated, andin angular pieces.
Lustre splendent. Fracture perfect conchoi-
d:d.   Semi-transparent.   Scratches glass.
Brittle.   Adheres :o the tongue.  Infusible.
Its constituents are, silica 93.5, oxide oi iron
1, water 5.—Klaproth.   It occurs  in veins
alonir with  precious opal in clay.porphyry,
and in metalliferous veins  in Cornwall, Ice-
land, and the north of Ireland.
  3. Fire opal.   Colour hyacinth-red.  Lus-
tre splendent. Indistinct concretions. Frac-
ture perfect conchoidal. Completely trans-
parent.  Hard.  Tncommonly easily  fran-,
gible.  Sp. gr. 2 12.  Heat changes the co-
lour to  pale flesh-red.   Its constituents are,
silica 92, water  7.75,  iron 0.25.  It has
been found only  at  Zimapan  in Mexico,
in  a  particular  variety of hornstone por-
phyry.
  4. Mother-of-pearl opal, or Caeholong.  It
is described under Cacholong, as a variety
of calcedony.
  5.  Semi-opal.  Colours white, gray, and
brown ;  sometimes in  spotted, striped, or
elouded delineations.  Massive, disseminat-
ed, and in imitative shapes.  Lustre  glisten-
ing.   Fracture  conchoidal.   Translucent.
Semi-hard.   Rather easily frangible.  Sp.
gr. 2.0.  Infusible.  Its constituents are, si-
lica 85, alumina 3, oxide of iron  1.75, car-
bon 5, ammoniacal water 8, Lituminous oil
0.33.—Klaproth.  It occurs in porphyry and
amygdaloid, in  Greenland,  Iceland, and
Scotland, in the Isle of Runie, &c.
   6.  Jasper opal, or Ferruginous opal.   Co-
lour scarlet-red, and gray.  Massive.  Lus-
tre shining. Fracture  perfect conchoidal.
Opaque.  Between hard and semi-hard.
Easily  frangible.   Sp.  gr. 2.0.   Infusible.
Its constituents are. silica 43.5, oxide of iron
47,0, water 7.5.—Klap>-oth.  It is found in
porphyry at Tokay in Hungary.
  7. Wood opal.  Colours very various'.   In
branched pieces and stems. I. stre shining.
Fracture conchoidal.   Translucent.   Semi-
hard in a high degree.   Easily frangible.
Sp. gr. 2.1.  It is  found in alluvial land at
Zastravia in Hungary.*
  * Opium.  See Moiphia, and Acid (Me-
conic).  In the 8th and 9th volumes of the
Journal of Science, and  in the  1st of  the
Edinburgh Phil. Journal,  are two valuable
papers on the manufacture of British opium;
the first by the Rev. G. Swayne, the second
by Mr. Young.   The manufacture of Indian
opium has been  of  late years  greatly  im-
proved by Dr. Fleming, M. P., under whose
superintendence that important department
was placed by the Marquis of W ellesley.'
  According to Orfila, a dangerous dose of
opium is rather aggravated than counteract-
ed  by vinegar.  The proper remedy is a
powerful emetic, such as sulphate of zinc, or
sulphate of copper.  See an interesting and
well treated case, in the  1st volume of the
Medico-Chiivrgical Trans, by  Dr.  Marcet
and Mr. Astley Cooper.*
  Opobalsam.  The  most precious of the
balsams is  that commonly called Balm of
Gilead,  Opobalsamum,  Balsumadeon, 15al-
samum verum album, /Egyptiacum, Judai-
cum,  Syriacum, e  Mecca, &c.   11, s is the
produce of the amyris opobalsamum, L.
  The true balsam is of a pale yellowish
colour, clear and transparent, about the con-
sistence of Venice turpentine, of a  strong,
penetrating, agreeable, aromatic smell,  and
a slightly bitterish pungent taste. By age it
becomes yellower, browner, and thicker,
losing by degrees, like volatile oils, some of
its finer and more subtile  parts.  To spread,
when dropped into water, all over the  sur-
face,  and to form a fine, thin, rainbow-
coloured cuticle, so tenacious that it may be
taken up entire by the point of a needle,
were formerly infallible criteria  of the ge-
nuine opobalsam.  Neumann, however, had
observed, that other balsams, when ofa cer-
tain degree of consistence, exhibit these phe-
nomena equally with the Egyptian. Accord-
ing to Bruce, if dropped on a woollen cloth,
in its  pure and fresh state, it may be washed
out completely and readily with simple wa-
ter.
   Opodeldoc  A solution of soap in alco-
hol, with the addition of camphor, and vola-
tile oils.   It is used externally against rheu-
matic pains, sprains, bruises,  and other like
complaints.
   Oio.'avax.   A concrete gummy resinous
juice, obtained from  the  root* of an umbel-
liferous plant, the pastinaca opopanax, Linn.
which grows spontaneously in  the warmer
countries, and bears  the colds of this.  The
juice is brought from Turkey and the  Ka.-rt
Indies, sometimes in round drops  or tears,
but more commonly in irregular lumps, ofa
reddish-yellow tolour on the outside,  with 
ORE                                   ORE
 specks of white; inwardly ofa paler colour,
 and frequently variegated with large white
 pieces.  It has a peculiar strong smell, and
 a bitter, acrid, somewhat  nauseous taste.
   * Ores.  The mineral bodies, from which
 metals are extracted.
   I.—Antimony, Ores of.
   1. Native antimony,  of which there are
 two species; dodecahedral,  and  octohe-
 dral.
   1. Dodecahedral.  Colour tin-white. Mas-
 sive and crystallized in an octohedron and
 dodecahedron. Harderthan calcareous spar.
 Sp. gr. 6.7.  It consists of 98  antimony,
 1.0  silver, and  0.25 iron.   It is found in
 argentiferous veins in the gneiss mountains
 of Chalanches in Dauphiny, and at Andreas-
 berg in the Hartz.
   2. Octohedral  antimony,-  of which there
 are two sub-species,  the  antimonial  silver,
 and arsenical silver.  See O u:s of Silver.
   II. Antimony Glance. Under  this ge-
 nus are ranged  the  following species, sub-
 species, and kinds.
   1. Compact gray antimony.  Colour light
 lead-gray.  Massive   Soft.   Easily frangi-
 ble.  Sp.  gr. 4.4.  Found in Hud  Boys
 mine in Cornwall.
  2. Foliated gray  antimony.  Colour like
 the  preceding.   Cleavage prismatic. Not
 particularly brittle.   Sp.  gr. 4.4.
   3. Radiated gray antimony.  Colour com-
 mon lead-grav.  Massive, and crystallized in
 four and six-sided prisms, and sometimes in
 acicular crystals.  Lustre metallic.   Sp. gr.
 4.4.  It melts by the flame ofa candle. Its
 constituents  are, antimony  75, sulphur 25.
 These minerals occur in veins, in primitive
 and transition mountains.  This occurs in
 Glendinning   in  Dumfries-shire; in  Corn-
 wall, &c.
  4. Plumose  gray antimony.   Colour be-
 tween dark lead-gray and smoke-gray. Mas-
 sive, and  in  capillary  glistening  crystals.
 Lustre semi-metallic.  Very soft.   It melts
 into a  black  slag.   It contains  antimony,
 sulphur, arsenic, iron, and silver.   It occurs
 in veins in primitive rocks, at Andreasberg
 in the  Hartz, &c.
  5. Axifrangible antimony glance, or Bour-
nonite.   Colour  blackish  lead-gray.   Mas-
 sive and crystallized.  Primitive form, an
oblique four-sided prism,  which occurs va-
riously modified by truncation, &c.  Lustre
metallic.  Cleavage axifrangible.   Fracture
Conchoidal. Brittle   Sp. gr. 5.7.  Its con-
stituents are,  lead 42.62. antimony £4.23,
copper 12.8, iron 1.2, sulphur 17.—Hatchett.
It is found near Endellion in  Cornwall.
  6. Prismatic  antimony  glance.   Colour
blackish lead-gray.   Primitive  form, an
oblique four-sided prism.  Lustre metallic.
Cleavage in the direction ofthe smaller dia-
gonal ofthe prism.   Sp. gr. 5.75.
  HI. Antimony ochre. Colour straw-yellow,
incru6ting crystals of gray antimonv.  Dull.
   Vot. J I.
Fracture earthy. Very soft. Brittle. Whitens
and evaporates before the blow-pipe.  It oc-
cnrs in veins in Saxony, &c.
   IV.  Ntckeliferous gray antimony.  Colour
steel-gray.  Massive.  Shining.  Cleavage
double rectangular.  Fragments  cubical,
Brit'le.  Sp. gr. 6. to 6.7.   It melts before
the blow-pipe, emitting white vapour of ar-
senic.   It communicates a green colour to
nitric  acid.  It consists  of antimony, with
arsenic 61.68,  nickel 23.33, sulphur 14.16,
silica,  with silver and lead, 0.83, and atrace
of iron.  It occurs in veins near Freussberg
in Nassau.
   V.  Prismatic white  antimony.   Colour
white.  Massive and crystallized, in a rec-
tangular four-sided prism,  an oblique four-
sided prism, a rectangular four-sided  table,
a  six-sided prism,  and in acicular and capil-
lary crystals.  Lustre pearly or adamantine.
Cleavage in the  direction of the lateral
planes. Translucent. Sectile.  Sp. gr.  5.0 to
5.6.  It melts and  volatilizes in a white va-
pour.  Its constituents are, oxide of antimo-
ny 86,  oxides of antimony and iron 3,  silica
8.  It  occurs in veins in primitive rocks, in
Bohemia and Hungary.
   VI.  Prismatic antimony-blende, or rejd anti-
mony.
   a. Common.  Colour  cherry-red.   Mas-
sive, in flakes, and crystallized.  Primitive
form, an oblique four-sided prism.  Crystals
delicate, capillary.  Adamantine.  Translu-
cent on the  edges.   Brittle.  Sp. gr. 4.5 to
4.6.  It melts and evaporates before  the
blow-pipe.   It consists  of antimony 67.5,
oxygen 10.8, sulphur 19.7.—Klapr.  It  oc-
curs at Braunsdorf in Saxony.
   b. Tinder antimony-blende. Colour muddy
cherry-red.   In  flexible  tinder like leaves.
Feebly glimmering. Opaque.  Streak shin-
ing. Friable.  Sectile and flexible. It con-
tains oxide of antimony 33, oxide of iron  40,
oxide of lead 16, sulphur 4, with some silver.
— Link.  It occurs in the Carolina and Do-
rothea mines at Clausthal.
   II.—Arsenic.
   1. Native arsenic.  Fresh fracture,  whit-
ish lead-gray.  Massive,  and  in imitative
shapes.  Feebly glimmering.  Harder than
calcareous spar.  Streak shining,  metalfrc.
When  struck, it has a ringing sound, and
emits an arsenical odour.  Sp. gr.  5.75.   It
occurs in veins in primitive rocks, atKongs.
berg in Norway, Sec.
   2. Oxide of arsenic; common, capillary,
and earthy.
   a. Common oxide has a white colour ;
occurs in  crystalline crusts; has a shining
lustre; uneven fracture; and  is  soft and
semi-transparent.
   b. The capillary  occurs  in silky, snow-
white,  shining, capillary crystals.
   c. The earthy  is  yellowish-white;  in
crusts.   Dull,  opaque, and friable. It oc»
curs at Andreasberg in the Hartz.
                26 
ORE                                   OKE
  3. Arsenical pyrites.
  a. Common arsenical pyrites.  Mispickel.
Fresh fracture silver-white.  Massive and in
 {irismatic concretions.   Crystallized in ob-
 ique four-sided prisms.   Lustre splendent
metallic. Fracture coarse-grained. Cleavage
in the direction of the perpendicular prism.
Sometimes as hard as feldspar.   Brittle.  It
emits an arsenical smell on friction. Sp. gr.
5.7 to 6.2.  Before the blow-pipe it yields
a copious arsenical vapour.  Its constituents
are, arsenic 43.4, iron  34.9, sulphur  20.1.
It occurs in primitive rocks, in Cornwell and
Devonshire, and at Alva in Stirlingshire.
  6. Argentiferous arsenical pyrites.  Colour
silver-white.  Disseminated, and in very small
acicular oblique four-sided prisms.  Shining
and metallic.   Besides arsenic  and iron, it
contains from 0.01 to 0.10 of silver,   It has
been found in  Saxony; and is used  as an
ore of silver.
  4. Pharmacolite,  or  arsenic-bloom.    Co-
lour reddish-white.  As a coating of balls,
or in delicate capillary shining silky crystals»
Semi-transparent, or opaque.   Soft.  Soils.
Sp. gr. 2.64.  Its constituents are, lime 25
arsenic acid 50.44,  water  24.56.  It occurs
in veins along with tin-white cobalt, at An-
dreasberg, &c.
   5. Orpiment.
  a. Red,  ruby sulphur,  or hemi-prismatic
sulphur    Colour aurora-red ; massive -,  in
flakes, and crystallized in oblique four-sided
prisms.    Lustre inclining  to  adamantine.
Fracture  uneven.   Translucent.   Streak
orange-yellow  coloured.  As hard as talc.
Brittle.  Sp. gr. 3.35.   It melts and  burns
with a blue flame.  It is idio-electric by fric-
tion. Its constituents are,  arsenic 69, sul-
phur 31.  It occurs in primitive rocks at
Andreasberg, &c.
   b. Yellow  orpiment,  or prismatoidal sul-
phur.  Colour  perfect lemon-yellow.   Mas-
sive, imitative, and crystallized in oblique
four-sided prisms,  and  in flat double  four-
sided  pyramids.  Cleavage  prismatoidal.
Translucent.   Harder than the red.   Flexi-
ble, but not elastic.  Splits easily.  Sp. gr.
3.5.  Its constituents are arsenic 62, sulphur
38. It occurs in veins in floetz rocks ; and
along with red silver in granite at Wittichen
in Swabia.
   111.—Bismuth.
   1. Native or  octohedral  bismuth.   Fresh
 fracture silver-white, inclining to red.  Mas-
 sive and crystallized in an octohedron, tetra-
 hedron, and cube.  Lustre splendent, me-
 tallic.   Cleavage  fourfold.   Haider than
 gypsum.   Malleable.   Sp. gr. 8.9 to 9.0.
 It melts by the flame of a candle.   It occurs
 in veins in mica-slate, &c- at St. Columb
 and Botallack, in Cornwall; and in Saxony.
    2. Bismuth-glance.
    a. Acicular bismuth-g'ance.  Colour dark
  lead-gray.  Disseminated, and crystallized
  in oblique four or six-sided prisms.   Lus-
tre splendent, metallic.  Fracture uneven.
Opaque.   Brittle.   Sp. gr. 6.1 to 6.2.   It
fuses before the blow-pipe into a steel-gray
globule.  Its constituents are, bismuth 43.2,
lead  24.32,  copper  12.1,  sulphur 11.58,
nickel 1.58, tellurium 1.32, gold 0.79.  It
occurs imbedded in quartz near Beresof in
Siberia.  It is also called needle ore.
  b.  Prismatic bismuth-glance.  Colour pale
lead-gray.   Massive, and crystallized in aci-
cular and capillary oblique four and six-si-
ded prisms.  Lustre splendent, metallic.  It
soils; is brittle;  and harder than gypsum.
Sp. gr. 6.1 to 6.4. It melts in the flame  of
a candle.  Its constituents arebismuih 60,
sulphur 40. It occursin veins in Cornwall, &.c.
   a. Cupreous bismuth   Colour light lead-
gray.  Massive.   Shining. Sectile.  Its con-
stituents are,  bismuth 47.24, copper 34.66,
sulphur  12.58.   It occurs in  veins in gra-
nite  near W ittichen in Furstemberg.
   b. Bismuth  ochre.   Colour  straw-yellow.
Massive.   Lustre inclines  to adamantine.
Opaque.   Soft.  Brittle.  Sp. gr. 4.37.  It-
dissolves with effervescence  in acids.  Its
constituents are,  oxide of bismuth 86.3, ox-
ide of iron 5.2, carbonic acid 4.1, water 3.4.
It occurs along with red cobalt.   It is found
at St. Agnes in Cornwall.
   IV.—Cerium.   See Allanite, Cerite,
Gadolinite,  Orthite,  Yttrockihte.  A
fluate and sub fluate  of cerium  have been
also discovered at Finbo in Sweden.
   V.—Cobalt Ores.
   1. Hexahedralcoba.lt pyrites, or silver-white
cobalt.  Colour silver-white.  Massive, and
crystallized in the cube, octahedron,  cube
truncated, pentagonal dodecahedron, icosa-
hedron.  Splendent, and metallic. Cleavage
hexahedral.   Fracture conchoidal.  Semi-
hard.  Brittle.  Streak  gray.  Sp.  gr. 6.1
to 6.3.   Before the blow-pipe, it gives out
an arsenical odour; and, after being roasted,
colours glass of borax smalt-blue.   Its con-
stituents are, cobalt 44, arsenic 55, sulphur
0.5.  Iron is sometimes present.   It occurs
in primitive rocks at Skutterend,in Norway.
It is the principal ore of cobalt.
   2. Octohedral cobalt pyrites.
   a.  The  tin-white,-  of  which there is the
compact and radiated.  The compact  has a
tin-white, and sometimes rather dark colour.
It  occurs massive  and crystallized in the
 cube, octohedron, and rhomboidal dodeca-
 hedron, truncated  on the  six  four-edged
 angles    Crystals generally rent and crack-
 ed.   Lustre  splendent, metallic.   Brittle.
 Sp. gr.  6.0  to  6.6.  Its constituents are,
 arsenic 74.22, cobalt 20.3, iron 3.42, copper
 0.16, sulphur 0.89.   It  occurs  in granite,
 gneiss, &c. in Cornwall, Saxony, &c.
   The radiated; cojour tin-white, inclining
 to gray.   Massive, and in distinct radiated
 concretions.   Lustre glistening, metallic.
 Softer than the  compact.  Its constituents
 are, arsenic 65.75,  cobalt 28, oxide of iron 
ORE                                  ORE
5.0, oxide of manganese 1.25.  It occurs in
clay-slate at Schneeberg.
   b. Gray octohedral cobalt pyrites.   Colour
fight  steel-gray.   Massive, and tubiform.
Dull, and tarnished  externally.  Internally
splendent metallic.  Fracture even. Streak
shining.  Brittle.   When struck,  emits an
arsenical odour.  Sp. gr. 6.135.  It contains
19.6 of cobalt, with iron and arsenic.   It oc-
curs in granite, gneiss, &c.   It is found in
Cornwall, Norway, &c.  It affords  a  more
beautiful blue smalt than any of the  other
cobalt minerals.
   Cobalt-kies.  Colour pale steel-gray. Mas-
sive, and in cubes.   Lustre metallic.  Frac-
ture uneven.  Semi-hard.  Its constituents
are, cobalt 43.2, sulphur 38.5, copper 14.4,
iron 3.53.  It  occurs in a bed of gneiss in
Sweden.
   3.   Red cobalt.
   a.   Radiated red cobalt, or cobalt bloom.
Colour crimson-red, passinginto peach-blos-
som.  Massive, imitative, and crystallized, in
a  rectangular  four-sided prism, or a com-
pressed  acute double six-sided pyramid.
Crystals  acicular.  Shining.   Translucent.
Rather sectile.  Sp. gr. 4.0 to 4 3.  It tinges
borax glass-blue.  Its  constituents are, co-
balt 39, arsenic acid 38, water 23.  It occurs
in veins in  primitive, transition, and second-
ary rocks.   It is found at Alva in Stirling-
shire, in  Cornwall, &c.
   b.  Earthy red cobalt, or cobalt crust.  Co-
lour, peach-blossom red.  Massive, and imi-
tative.  Friable.   Dull.   Sectile.  Streak
shining.   Does not sdl.
   c. Slaggy red cobalt. Colour muddy crim-
son-red.   In crusts and reniform.  Smooth.
Shining.   Fracture conchoidal.   Translu-
cent.  Soft and brittle.  It occurs at Furs-
temberg.
   4.   Cobalt ochre.
   a.   Black.   The earthy-black has a dark
brown colour; is friable, has a shining streak,
and feels meagre.  The indurated black has
a bluish-black  colour; occurs  massive  and
imitative;  has  a glimmering lustre;  fine
earthy fracture; is opaque; soft;  sectile;
soils; sp. gr. 2. to 2.4.  It consists of black
oxide of cobalt, with arsenic and oxide of
iron.   These two sub-species occur usually
together; in primitive or secondary moun-
tains;  at Alderly Edge, Cheshire, in  red
sandstone;  at Howth, near Dublin, in slate-
clay.
   b.  Brown  cobalt-ochre.    Colour  liver-
brown.  Massive.   Dull.   Fracture,  fine
earthy.  Opaque.   Streak shining;   soft,
sectile, light.   It consists of brown ochre of
cobalt, arsenic, and oxide of iron.  It oc-
curs chiefly in secondary mountains.  It is
found at Kamsdorf, in Saxony.
   c.   Yellow cobalt-ochre.  Colour muddy
straw-yellow.  Massive and incrusting. Rent.
Dull. Fracture fine earthy. Streak shining.
Soft and sectile. Sp. gr.  2.67, after absorb-
ing water.  It is the purest of the cobalt-
ochres.   It is found with the preceding. It
contains silver.
  5. The sulphate of cobalt is found at Biber,
near Hannau, in Germanv.   It consists of
sulphuric acid 19.74, oxide of cobalt 38.71,
water 41.55.   It has a light flesh-red co-
lour; and astalactitical form.  Streak yel-
lowish-white.  Taste styptic.
  VI.—Copper Ores.
  1. Octohedral, or native coppei'.  Colour
copper-red,frequently incrusted with green.
Massive, imitative,  and crystallized; in the
perfect cube; the  cube truncated, on  the
angles, on the edges, and  on the edges and
angles;  the garnet dodecahedron; perfect
octohedron;   and   rectangular  four-sided
prism.  Lustre glimmering, metallic. Frac-
ture hackly.  Streak splendent, metallic.
Harder than silver.  Completely malleable.
Flexible, but not elastic.  Difficultly  fran-
gible.   Sp. gr. 8.4 to 8.7.   It consists of
99.8 of copper,  with  a trace of gold and
iron.  It occurs in  veins, in granite, gneiss,
&c. and is found chiefly in Cornwall.
  2.  Octohedral red copper ore-
  a.  Foliated red copper ore.  Colour  dark
cochineal-red.   Massive,  and crystallized,
in the perfect octohedron,  which is the
primitive  form; in the octohedron, trun-
cated on the angles; on the edges, with
each  angle acuminated  with four planes;
bevelled on the edges, and each angle acu-
minated with eight planes. Lustre adaman-
tine, inclining to semi-metallic.   Cleavage
fourfold. Translucent on the edges, or trans-
lucent.   Streak muddy tile-red.   Hardness
between calcareous and fluor spar. Brittle
Sp. gr. 5.6 to 6.0
  b.  Compact  red copper  ore.  Colour be
tween lead-gray and cochineal-red. Massive
and reniform.  Lustre semi-metallic. Frac-
ture even.  Opaque. Streak tile-red. Brittle.
  c. Capillary red  copper ore.  Colour car-
mine-red.   In  small   capillary  crystals.
Lustre adamantine.  Translucent.
  The whole of these red ores are deutox-
idejj of copper, and are easily reduced to
the  metallic state  before the  blow-pipei
They dissolve with  effervescence when
thrown  in powder into nitric acid; and a
green nitrate  results.  In muriatic acid no
effervescence takes place.   'They  occur
principally  in veins that traverse primitive
and transition  rocks;  abundantly in the
granite  of Cornwall.  The earthy red cop-
per ore,  which  is  rare, is a sub-species of
the preceding.
  d.  Tile ore.  The  earthy tile ore has a
hyacinth-red colour.  It occurs massive and
incrusting copper  pyrites.  It is composed
of dull dusty particles.  It soils slightly, and
feels meagre.  It occurs in veins, as at Lau-
terberginthe  Hartz.  The  indurated tile
ore has an  imperfect  fiat conchoidal frac-
ture; a streak feebly shining ; and is inter- 
ORE
ORE
  mediate between  semi-hard and soft.  It is
  an intimate combination  of red copper ore
  and brown iron ochre,  containing from  10
  to 50 per cent of copper.
    3. Jilack copper, or black oxide of copper.
  Colour between bluish and brownish-black.
  It occurs  massive, and thinly coating cop-
  per pyrites.   It is composed of dull  dusty
  particles, which  scarcely  soil.   Streak
  slightly shining.  Before  the blow-pipe it
  emits a sulphureous odour, melts into a slag-,
  and communicates a'green colour to borax.
  It is said to be an oxide of copper with ox-
  ide of iron.  It occurs at Carharrack and
  Tincroft mines, in Cornwall.
   4. Emerald  copper,  or dioptase.   Colour
  emerald-green.  It occurs only crystallized.
  The primitive  form is a rhomboid of 123y
  58'.  The only secondary form at present
  known, is the equiangular six-sided prism.
  Lustre shining, pearly. Cleavage threefold.
  Fracture  small conchoidal.  Translucent.
 As hard as apatite. Brittle.  Sp. gr. 3.3.  It
 becomes a chesnut-brown before the blow-
  pipe, and tinges the flame green, but is in-
 fusible ; with borax it gives a bead of cop-
 per.  Its constituents are, oxide of copper
 28.57^ carbonate of lime 42.83, silica 23.57.
 — Vauq.  By Lowitz, it consists of 55 oxide
 of copper,  33  silica, and 12 water, in 100.
 It  is found in  the land of Kirguise, 125
 leagues from the Russian frontier, where it
 is associated with malachite and hmestone.
   5.  Blue copper, or prismatic malachite, of
 which there are two kinds, the radiated and
 earthy.
   The  radiated has an azure-blue colour.
 Massive, imitative, and crystallized. Its pri-
 mitive form is  an oblique prism.  The se-.
 condary forms are, an oblique four-sided
 prism, variously bevelled, and a rectangular
 four-sided prism, or eight-sided  prism, acu-
 minated with four planes.  Lustre vitreous.
 Cleavage threefold.   Fracture  imperfect
 conchoidal   'Translucent.  Colour of the
 streak, lighter.  Harder  than  calcareous
 spar.  Brittle.   Sp. gr. 3.65.  It is soluble
 with effervescence  in nitric acid.  With bo-
 rax it yields a metallic globule, and colours
 the flux green.  Its constituents are,  cop-
 per 56, carbonic acid 25,  oxygen  12.5, wa-
 ter 6.5.— Vauquelin.  It is found  at Lead-
 hills in Dumfries-shire, and Wanlockheadi.n
 Lanarkshire, and at Hud-Virgin and  Car-
 harrack in Cornwall, and in many places on',
 the Continent.
  b.  Earthy blue copper.  Colour  smalt-
 blue.  Massive.  Friable. Sp. gr. 3.354.  It is
 found in Norway, &c.
  'The velvet-blue  copper belongs to the
 same species. Lustre glistening and pearly.
It has been found  only at Oravicza in the
Bannat, along with malachite and the brown
iron-stone.
  6. Malachite,- of which there are,  the
fibrous and compact.
   a. Fibrous maUuMte. Colotir perfect eme,
 raid green.  Imitative, and  crysialh/ed, in
 oblique four-sided prisms, variously bevel-
 led or truncated ; and  in  an acute-angular
 three-sided  prism. Cry suds short, capillar),
 and acicular. Lustre pearly or silky. Trans-
 lucent, or opaque.  Suiter than blue cop-
 per.  Streak pale green.  Brittle.  Sp.gr,
 3.66.   Before  the blow-pipe it decrepitates,
 and becomes  black.  Its  constituents are,
 copper 58,  carbonic acid  18, oxygen 12.5,
 water  11.5.—Klaproth.  It  occurs princi-
 pally in veins.  It is found at Sandlodgc in
 Mainland, one of the  Shetlands; at Lan-
 didno in Caernarvonshire; and in the mines
 of Arendal in Norway.
   b.  Compact  ma/ac/ute.   Colour emerald-
 green.  Massive, imitative, and in four-sided
 prisms.  Glimmering and  silky.   Fracture,
 small grained  uneven.  Opaque.  Streak
 pale green.  Sp.  gr. 3.65.   In veins, which
 traverse different rocks in Cornwall, Nor-
 way, &c.  Brown copper from Hindostan is
 placed after  this mineral by Professor Jame-
 son.   Its colour  is  dark blackish-brown.
 Massive,   Soft.  Sp. gr. 2.62.   It efl'ervc-^-
 ces in acids,  letting fall a red  powder.   Its
 constituents  are,  carbonic acid 16.7, deut-
 oxide of copper  60.75, deutoxide of iron
 19.5, silica 2.1.—Dr. Thomson.
   7.  Copper-green.
   Common copper-green, or chrysocolla, con-
 tains three sub-species.
   a.  Conchoidal copper-green.  Colour ver-
 digris-green.  Massive,  imitative,  and  in.
 crusting.   Glistening. Fracture conchoidal,
 Translucent.   Haider than gypsum. Easily
 frangible.  Sp. gr. 2.0 to 2.2.   It becomes
 blaek and then brown before the blow-pipe,
 but  does not fuse.  It melts  and  yields a
 metallic globule with borax.  Its constitu-
 ents are, <y>pper40, oxygen 10, carbonic acid
 7, water 17, silica 26.—Klaproth. It accompa-
 nies malachite.  It is found in Cornwall, &c.
   Siliceous copper, or kieselkupfer, is a varie-
 ty of the above.  Colour asparagus-green.
 In crusts. Glistening.  Fracture  even  or
 earth).  Opaque.  Soft.   Its  constituents
 are,  copper J7.8, oxygen 8, water 21.8, sili-
 ca 29, sulphate of iron 3.
   b. Earthy  iron-shot copper-green,   Colour
 olive green.  Massive and in crusts.  Friable,
 Opaque.  Sectile.
  c.  Slaggy  iron-shot copper-green.   Colour
 blackish-green. Massive. Glistening. Frac-
 ture  conchoidal.   Opaque.   Soft.  Easily
 frangible.  It is probably  a compound  of
 conchoidal copper-green and oxide of iron.
 Both  occur  together,  and pass into each
 other.  It occurs  in Cornwall, along with
 olivenite.
  8.  Prismatic vitriol, blue vitriol, or sulphate
 of copper.   Colour dark sky-blue.   Massive
imitative,  and crystallized.    The primitive
figure  is an  oblique four-sided  prism,  in
which the lateral edges are 124° 2^ and 55** 
ORE                                   ORE
 5S7; with edges and angles often truncated.
 Shining.  Cleavage double.   Fracture con-
 choidal.  Translucent.  Harder than gyp-
 sum.  Sp. gr. 2.1 to 2.2.  Taste nauseous,'
 bitter, and metallic.  Its solution coats iron
 with metallic copper.  Its constituents are,
 oxide of copper 32.13, sulphuric acid3l.57,
 water  36.3.—Berzelius.  It  occurs  along
 with copper pyrites, in Parys-mine in An-
 glesea, and^n Wicklow.
   9.  Prismatic olivenite,  or phosphate of top-
 per.  Colour emerald-green.  Massive, and
 in oblique four-sided prisms of 110°.  Cleav-
 age double oblique.   Glistening. Fracture
 splintery. Opaque.  Streak verdigris-green.
 As hard as  apatite.   Brittle.  Sp. gr. 4. to
 4.3.  Fuses into  a brownish globule.  Its
 constituents  are, oxide of copper  68.13,
 phosphoric acid  30.95,   It is found at Vir-
 nebirg on the Rhine, along with quartz, red
 copper ore, &c.
   10. Di-prismatic olivenite, or lenticular cop-
 per.  Colour sky-blue.  Massive, but gene-
 rally crystallized. In  very  oblique  four-
 sided prisms, bevelled;  in rectangular dou-
 ble four-sided pyramids; shining;  fracture
 uneven;  translucent. Harder than gypsum.
 Brittle.   Sp. gr. 2.85.   Converted by the
 blow-pipe into a black friable  scoria.  Its
 constituents are, oxide of copper 49, arsenic
 acid  14,  water 35.— Chenevix.  Found in
 Cornwall.
   11.  Acicular olivenite.  a. Radiated or  cu-
 preous arseniate of iron.  Colour dark verdi-
 gris-green.  Massive, imitative and  in  flat
 oblique  four-sided  prisms, acuminated or
 truncated. Lustre glistening pearly. Trans-
 lucent on the edges.  As hard as calcareous
 spar.  Brittle.  Sp. gr. 3.4.
   b. Foliated acicular olivenite;  arseniate of
 copper.  Colour dark olive-green.   In  an-
 gulo-granular concretions, and in small crys-
 tals;  which are oblique four-sided prisms;
 and acute double four-sided pyramids. Glis-
 tening.  Fracture conchoidal. Translucent.
 Streak olive-green.   As hard as calcareous
 spar.  Brittle.  Sp. gr. 4.2 to 4.6.  It boils,
 and gives a hard reddish-brown scoria be-
 fore the blow-pipe.  Its constituents are,
 oxide of copper  60, arsenic acid 39.7___
 Chenevix.   In the copper mines of Corn-
 wall.
  c.  Fibrous  acicular   olivenite.   Colour
 olive-green.   Massive,  reniform,  and  in
 capillary  and acicular oblique  four-sided
 prisms.  Glistening  and pearly.  Opaque.
 As hard as calc-spar.  Brittle.  Fibres some-
 times flexible.  Streak  brown  or yellow,
 Sp. gr. 4.1 to 4.2.  Its constituents are, ox-
ide of copper 50, arsenic acid 29, water 21.
 It occurs in Cornwall.
  d. Earthy acicular olivenite.  Colour olive-
 green.  Massive and in crusts.  Dull.  Frac-
ture fine earthy.  Opaque.  Very soft.  It
 n found in Cornwall.
   2.  Atacamite, or muriate of copper.
   a.  Compact, Colour leek-green. Massive^
 and in short needle-shaped crystals which
 are oblique four-sided prisms, bevelled or
 truncated.  Shining and pearly.  Translu-
 cent on the edges.   Soft.  Brittle.   Sp. gr.
 4.4 ?   It tinges the flame of the  blow-pipe
 of a bright green and blue, muriatic acid
 rises in vapours, and a bead of copper re-
 mains on the charcoal.  It dissolves with-
 out effervescence  in  nitric  acid.  Its con-
 stituents are,  oxide of copper 73.0,  water
 16.9, muriatic acid 10.1.—Klaproth.  It oc-
 curs in veins in Chili, and Saxony.
   b. Arenaceous  atacamite, or copper-sand.
 Colour grass-green. In glistening scaly par-
 ticles.  It does not soil.  It is translucent.
 Its constituents are, .oxide  of copper 63,
 water 12, muriatic acid 10, carbonate of iron
 1, mixed siliceous  sand 11   It is found in
 the sand of the river Lipes, 200 leagues be-
 yond Copiapu in the  desert of Atacama,
 which separates Chili  from Peru.
   13.  Copper Pyrites.
   a.  Octohedral copper pyrites. On the fresh
 fracture, its colour is brass-yellow;  but it is
 usually tarnished.   Massive,  imitative  and
 crystallized;  in a regular  octohedron, per-
 fect, truncated or bevelled; and in a perfect
 or truncated tetrahedron.  Glistening. Frac-
 ture  uneven.   Hardness from  calcareous
 to fluor spar.  Brittle.   Sp. gr.  4.1 to  4.2.
 Before the blow-pipe, on charcoal, it decre-
 pitates, emits a  greenish-coloured sulphu-
 reous smoke, and meltsinto a black globule,
 which  assumes metallic lustre.   It tinges
 borax green.   Its constituents are, copper
 30, iron 53, sulphur 12.— Chenevix.  It con-
 tains sometimes  a little gold or silver.  It
 occurs in all the great classes of rocks.  It is
 found near Tynedrum in Perthshire; at the
 mines of Ecton : at Pary's  mountain; abun-
 dantly  in Cornwall; and  in  the county of
 Wicklow in  Ireland.   The rich ores are
 worked for copper; the poor, for sulphur.
   b. Tetrahedral copper pyrites ; of which
 species there are two sub-species, gray cop-
 per and black copper.
   Gray-copper. Colour steel-gray.  Massive
 and'crystallized; in the tetrahedron, trun-
 cated or bevelled;  and  in the rhomboidal
 dodecahedron-  Splendent.   Fracture  un-
 even. Hardness as calcareous spar and fluor.
 Brittle.  Sp, gr. 4.41 o 4.9.  Its constituents
 are, copper 41, iron 22.5, sulphur  10, arsenic
 24.1,  silver 0.4.—Klaproth.   It  occurs in
 beds and veins in Cornwall, and many other
 places.
  Black copper.  Colour iron-black.  Mas-
 sive and crystallized;  in the tetrahedron,
 perfect, bevelled, or truncated. Splendent.
 Fracture conchoidal. Brittle.  Sp. gr. 4.85.
Its  constituents are, copper  39, antimony
 19.5, sulphur 26, iron 7.5,  mercury 6.25.—
Klaproth.  The mercury is accidental.  It
occurs in veins in the Hartz, and in Peru.
  14.  White copper.   Colour between silver- 
ORE                                   0RK
  white, and brass-yellow.  Massive and dis-
  seminated.  Glistening and metallic.  Frac-
  ture uneven.  Semi-hard.  Brittle.  Sp. gr.
  4.5.  It yields before the blow-pipe  a white
  arsenical vapour, and melts into a grayish-
  black slag.  It contains 40 per cent  of cop-
  per; the rest being iron, arsenic and sulphur.
  It occurs in primitive and transition rocks.
  It is found in Cornwall and Saxony.
    15.  Copper-glance, or vitreous copper.
    Rhomboidal copper-glance
    § 1. Compact.   Colour,  blackish  lead-
 gray.  Massive, in plates and crystallized.
 Primitive  form, a  rhomboid.  Secondary
 forms; a low equiangular six-sided  prism,
 and a double six-sided pyramid.  Glistening,
 metallic.   Harder than gypsum.  Perfectly
 sectile.  Rather  easily  frangible.  Sp. gr.
 5.5 to 5.8.  Its  constituents are,   copper
 78.05,  iron 2.25, sulphur 18.5, silica  0.75.—
 Klaproth.
   § 2.  Foliated.   Its constituents are,  cop-
 per 79.5,  sulphur 19, iron 0.75, quartz 1.—
 Ullmann.   It occurs in primitive rocks.  It
 is found also in transition rocks, at Fassney-
 burn in East Lothian; in Ayrshire ; at  Mid-
 dleton  Tyas in Yorkshire ; in Cornwall. &c.
   16.  Variegated copper.   Colour, between
 topper-red and pinchbeck-brown.  Massive,
 in plates, and crystallized in six-sided prisms.
 Glistening, metallic.  Soft.   Easily  frangi-
 ble.  Specific gravity, 5.  It is fusible, but
 not so easily as copper-glance, into a globule,
 which acts powerfully on the magnetic  nee-
 dle.  Its constituents are, copper 69.5, sul-
 phur 19,  iron  7.5,  oxygen 4.—Klaproth.
 It occurs  in gneiss, mica-slate, &c.   It is
 found in Cornwall.
   VII.—Gold Ores.
   1. Hexahedral,  or native gold.
   a. Gold-yellow native gold.   Colour,  per-
 fect gold-yellow.  Disseminated, in  grains,
 and crystallized; in the octohedron, perfect
 or truncated; in the cubo-octohedron; in
 the cube, perfect or truncated; in the dou-
 ble eight-sided pyramid ; in the tetrahedron,
 and rhomboidal dodecahedron. Splendent.
 Fracture,  fine  hackly.   Soft.   Difficultly
 frangible.  Malleable  Sp. gr. from 17 to 19,
 and so low as  12.  Fusible  into  a  glo-
 bule.  It is gold with a  very minute  por-
 tion of silver and copper.   It occurs in
 many very different rocks; and in  almost
 every country.  See an extensive enumera-
 tion of localities, in  Jameson's Mineralogy.
  b. Brass-yellow native gold,  occurs  capil-
 lary ; in octahedrons, and in six-sided  tables.
 Specific gravity,  12.713.  Its constituents
 are, gold  96.9, silver 2,  iron 1.1.   It is
 found in the gold mines of Hungary,  in Si-
 beria, &c.
  c. Grayish-yellow  native gold.   Colour
 brass-yellow verging on steel-gray.  In small
 flattish  grains.  Never crystallized.   It is
 said to  contain platina.  It is rather denser
than the last.  It occurs along with platina
and magnetic iron-ore in South America*
    d. Argentiferous gold,  or electrum.  Co-
  lour,  pale  brass-yellow.   In small  plates,
  and imperfect cubes.  Its constituents are,
  64 gold, 36  silver.  It occurs along with
  massive heavy spar in Siberia   Klaproth
  says, it is acted on neither by nitric  nor ni-
  tro-muriatic acid.   See Tei.hjiu' m Ores.
    VIII.—Iridium Ore.  Colour, pale steel-
  gray.  In  very small irregular flat  grains.
  Lustre shining and metallic.  Ejacture foli-
  ated.  Brittle.  Harder than platina.  Sp.
  gr. 19.5.  By fusion  with nitre,  it acquires
  a dull black colour, but recovers its original
  colour and  lustre, by heating with charcoal.
  It consists of iridium, with  a portion of os.
  mium.  It  occurs in alluvial soil in South
  America, along with platina.— Wollaston.
    IX.—Iron Ore.
    I. Native, or octohedral iron.
    a.  Terrestrial native  iron.  Colour, steel*
  gray.  Massive, in plates and leaves.  Glis-
  tening-,  and  metallic.   Fracture hackly,
  Opaque.    Malleable.  Hard.   Magnetic.
  Its constituents are, iron 92.5,  lead 6, cop-
  per 1.5 —Klaproth.  It  is found with  brown
  iron-stone and quartz in a vein, in the moun-
  tain of Oulle, in the vicinity of Grenoble, &c.
   6. Meteoric   native iron.   Colour, pale
  steel-gray, inclining to silver-white.   Gene-
  rally covered with a thin brownish crust of
  oxide of iron.   It occurs ramose, imperfect
  globular,  and disseminated in  meteoric
  stones.  Surface, smooth and  glistening.
  Internally,  it is intermediate between glim-
  mering and  glistening, and the lustre is me-
  tallic.  Fracture hackly.  Fragments blunt-
  edged.  Yields a  splendent streak.   Inter-
 mediate between soft and  semi-hard.   Mai-
  leable.  Flexible, but not elastic.  Very dif-
  ficultly frangible.  Sp. gr. 7.575.  Its coil-
  stituents are,
        Agram. Arctic. Mexico.  Siberian.
  Iron,     96.5      97      96.75      90.54
  Nickel,   3.5       3       3.25       9.46

         100.0    100    100.00    100.00
        Klapr. Brande.  Klapr.   Children.
 The American native iron contains 0.10 of
 nickel; the Siberian 0.17; and the  Sene-
 gambian 0.05 and 0.06.—Howard.   It  ap-
 pears to be  formed in the atmosphere, by
 some process hitherto unknown to us. See
 Meteorolite,  and  Jameson's Mineralogy,
 iii. p. 101.
   II.  Iron-ore.
   a.  Octohedral iron-ore, of which there are
 three kinds.
   § 1.  Common magnetic iron-ore.   Colour,
 iron-black.   Massive,  in granular  concre-
 tions, and crystallized: in the octohedron,
 truncated, bevelled and cuneiform;  rhom-
 boidal  dodecahedron; rectangular four-sid-
 ed prism; cube; tetrahedron; equiangular
 six-sided table ; and twin crystal.   Splen-
 dent,   and   metallic.   Cleavage  fourfold.
 Fracture  uneven.   Streak black.  Harder
than apatite.  Brittle.  Specific gTavity, 448 
ORE
ORE
 to 5.2. Highly magnetic, with polarity. Be-
 fore the blow-pipe it becomes  brown, and
 does not melt; it gives glass of borax a dark
 green colour. Its constituents are, peroxide
 of iron 69, protoxide of iron 31___Berzelius.
 It occurs in beds of great magnitude, in pri-
 mitive rocks, at Unst; at St. Just in Corn-
 wall ; at Arendal in Norway, &c.  It affords
 excellent  bar-iron.
   § 2.  Granular magnetic iron-ore,  or iron-
 sand.  Colour  very  dark iron-black.   In
 small grains and octohedral crystals.  Glim-
 mering.   Fracture   conchoicial.   Brittle.
 Streak black.  Sp.  gr. 4.6 to  4.8.  Mag-
 netical with polarity.   Its constituents  are
 oxide  of  iron  85.5, oxide of titanium  14,
 oxide of manganese 0.5.—Klaproth.   It oc-
 curs imbedded in basalt, &c. It is found in
 Fifeshire, in the Isle  of Skye,  in the river
 Dee in Aberdeenshire,  &c.
   §  3.  Earthy magnetic iron-ore.   Colour
 bluish-black.   In blunt-edged rolled pie-
 ces.  Dull.  Fracture, fine grained  uneven.
 Opaque. Soft. Streak black, shining. Soils.
 Sectile.   It emits a faint clayey smell when
 breathed on.  Sp. gr. 2.2.  It occurs in the
 iron  mines of Arendal in Norway.
   b.  Rhomboidal iron-ore; of which there
 are three  sub-species.
   § 1. Specular iron-ore, iron-glance, or  fer
 oligiste ofthe French.  Of this there are two
 kinds, the common and micaceous.  Com-
 mon  specular iron-ore.  Colour  dark  steel-
 gray.  Massive, disseminated,  and  crystal-
 lized.  Prim, form ; a rhomboid, or double
 three-sided pyramid, in which the angles are
 87° 9' and 92°  51'.   The secondary figures
 are,  the primitive form variously bevelled,
 truncated  and  acuminated; the flat rhom-
 boid  ; equiangular six-sided table; low equi-
 angular six-sided prism; and very acute six-
 sided pyramid.  Lustre, splendent metallic.
 Cleavage  threefold.   Fracture imperfect
 conchoidal.  Streak cherry-red. Hardness,
 between feldspar  and quartz.  Rather diffi-
 cultly frangible.  Sp. gr. 5.2.   Magnetic in
 aslightdegree.  Its constituents are, reddish-
 brown  oxide of  iron 94.38, phosphate of
 lime  2.75,  magnesia 0.16, mineral oil ? 1.25.
 —Hisinger.  It occurs in beds in primitive
 mountains.  It  is found at Cumberhead in
 Lanarkshire; at Norberg in Wesfcnannland,
 in Norway, &,c.  It affords an excellent mal-
 leable iron.
   Micacepus specular iron-ore. Colour iron-
 black.  Massive, disseminated and in small
 thinsix-sided tables, intersectingoneanother
 so  as to form  cells.   Splendent, metallic.
 Cleavage,  single curved-foliated.  Translu-
 cent in thin plates.  Streak cherry-red. As
 hard as  the above.  Most easily frangible.
 Sp. gr. 5.07.  It  slightly affects the magnet.
 It is peroxide of iron.   It occurs in beds in
mica-slate.   It  is  found at Dunkeld, and
Benmore in Perthshire; in several parts  of
England and Norway,  &c. The iron it a'f-
 fords is sometimes cold short, but is well
 fitted for cast ware.   It is characterized by
 its high degree  of  lustre, openness of its
 cleavage, and easy  frangibility.  It affords
 from 70 to 80 per cent, of iron.
   § 2.  Red iron-ore,- of  which  there are
 four kinds, the scaly, ochry, compact, and
 fibrous.-
   Scaly red iron-ore, or  red iron froth.  Co-
 lo«ir dark steel-gray, to brownish-red.  Fri-
 able, and consists of semi-metallic shining
 scaly parts, which are sometimes translucent
 and soil strongly. Its constituents are, iron
 66, oxygen 28.5, silica 4.25, alumina 1.25.
 —Henry.  But Bucholz found  it to  be a
 pure red oxide of iron, mixed with  a little
 quartz sand.   It  occurs in veins in primitive
 rocks.   It is found at  Ulverstone in Lan-
 cashire ;  in Norway, 8cc.
   Ochry red iron-ore, or red ochre.  Colour
 brownish-red. Friable.  Dusty  dull  par-
 ticles.   Soils.  Streak,  blood-red.   Easily
 frangible.  Sp.  gr.  2.947.  It  occurs in
 veins,  with the  preceding ore.  It melts
 more easily than any of the other ores of
 this metal, and affords  excellent malleable
 iron.
   Compact  red iron-ore.  Colour  between
 dark  steel-gray  and blood-red.  Massive,
 and in supposititious crystals; which are an
 acute double six-sided pyramid from calcare-
 ous spar; and a  cube from fluorspar and
 iron  pyrites.  Lustre metallic.   Fracture
 even.  Streak pale blood-red. Easily frangi-
 ble.  Sp. gr. 4.232.  When pure  it  does
 not aff'ect the magnet.  Its constituents are
 oxide of iron 70.5? oxygen  29.5?—Bw
 cholz.   It occurs in beds and veins in gneiss,
 &c.  It affords good bar and cast-iron.
   Fibrous red iron-ore, or red hematite.  Co-
 lour between brownish-red and dark steel-
 gray.   Massive, imitative, and in supposi-
 titious double six-sided  pyramids from cal-
 careous spar.   Glistening,   semi-metallic.
 Opaque.  Streak blood-red.   Brittle.  Sp,
 gr. 4.74.  Its constituents are,  90 oxide of
 iron, silica 2, lime  1, water 3.—Daubuis-
 son.  It occurs with  the compact.   It af-
 fords  excellent  malleable  and  cast-iron.
 Its powder is used for polishing tin,  silver,
 and gold vessels; and  for colouring  iron
 brown.
   § 3. Red clay iron-ore, or stone ; of which
 the varieties are,  the ochry, the columnar,
 the lenticular, and jaspery. The first is used
 for red crayons; and is called red-chalk.  It
 occurs in Hessia, &c.  The second consists
 of 50 oxide of iron, 13 water, 32 silica, and
 7  alumina.—Brocchi.  It is  rare,  and  is
 called a pseudo-volcanic product. The third
 affords excellent iron.  It consists of oxide
 of iron 64, alumina 23, silica 7.5, water 5.
The jaspery is found in Austria.
  c  Prismatic  iron-ore, or brown iron-stone.
Of this we have four sub-species.
  §  1.  Ochry  brown iron-ore.   Yellowish 
ORE                                  ORE
brown; massive;  dull;  fracture, earthy;
soils ;  soft;  sectile.  Its constituents are,
peroxide of iron 83, water 12, silica 5.  It
occurs with the following.
  $ 2. Compact.  Colour passes  to clove-
brown. Massive, and in supposititious crys-
tals from pyrites.  Dull.   Brittle. Sp. gr.
3 to 3.7.   It  contains 84 peroxide of iron,
11 water, and 2 silica.  It affords about 50
per cent, of good bar iron.
  § 3. Fibrous.  Clove-brown.  Imitative;
and in supposititious crystals.  Splendent ex-
ternally.   Glimmering internally.  Opaque.
Harder than  apatite.  Brittle.  Sp. gr. 3.9.
Streak pale yellowish-brown.  Its constitu-
ents are, 80.25 oxide of iron, 15 water,  3.75
silica.— Vauquelin.
  The preceding sub-species occur most fre-
quently in  transition and secondary moun-
tains.  They are found  in  veins in sand-
stone, along with heavy  spar, at Cumber-
head iu Lanarkshire, &c.   They melt easily,
and afford from 40 to 60 per cent of good
bar, but indifferent cast-iron.  Good  steel
may be made from it.
  § 4.  Brown clay iron-ore ; of which there
are five kinds, the common,  the pisiform,
the reniform, the granular, and umber.
  The first occurs massive; has a flat  con-
choidal fracture; a brown  streak; and is
soft.  It contains 69 oxide of iron, 3  man-
ganese, 13 water,  10 silica, and 3 alumina.
The second has a yellowish-brown  colour.
It occurs in  small  solid spherical grains,
composed of concentric concretions. Sp. gr.
3.142.  It consists of 48 oxide of iron, 31
alumina, 15  silica,  and 6 water.—Vauque-
fin.  It is  found in  hollows  in shell lime.
stone, at Galston in Ayrshire, &c.  It yields
from 40 to 50 per cent of iron; and in Dal-
matia it is used as small shot.   The tlurdh&s
a yellowish-brown cdour. Massive, and imi-
tative; in concentric lamellar concretions,
which often include a loose nodule.  Glim-
mering.  Sectile.   Its constituents are, per-
oxide of iron 76, water 14, silica 5, oxide of
manganese 2.  It occurs in iron-shot clay in
secondary  rocks.   It is  found in East and
Mid Lothian,  in  Colebrookdale,  &c.  It
yields an excellent iron.  The fourth,  or
granular,  occurs  massive and  in grains.
Fracture  thick slaty.   Streak   yellowish-
brown.  Soft.  Brittle.   Sp.  gr. 3.  It oc-
curs in beds between the red limestone of
the salt formation, and the lias limestone. It
13 found in Bavaria, France, &c.   It affords
about  40 per cent of  good iron.  Fifth,
Umber.  Colour  clove-brown.   Massive.
Dull.  Fracture,  flat  conchoidal.   Soft.
Sectile.  Soils  strongly.  Feels meagre.
Adheres strongly to the tongue, and readily
fells to pieces in water.  Sp. gr. 2.06.  It
consists of oxide of iron 48, oxide of man-
ganese 20, silica 13, alumina 5, water  i4.—
Klaproth.   It occurs in beds in the Island of
Cyprus.  It is used as a pigment
   Bog iron-ore is  arranged as a variety of
 the above.  There are three kinds of it.
   § 1. Meadow ore, or friable bog iron-ore.
 Colourpaleyellowish-brown.  Friable. Dull.
 Fracture, earthy.   Soils.  It feels meagre,
 but fine.
   § 2. Swamp ore, or  indurated  bog  iron-
 ore.  Colour dark yellowish-brown.  Cor-
 roded and vesicular.  Dull.  Earthy. Very
 soft.  Sectile.   Sp. gr. 2.944.
   § 3. Meadow ore, or  conchoidal bog  iron.
 ore.  Blackish-brown.  Massive, and tube-
 rose.  Glistening.  Fracture small conchoi-
 dal.  Streak yellowish-gray.   Soft.  Sp. gr.
 2.6.  Its constituents are, oxide of iron 66,
 oxide ofmanganese 1.5, phosphoric acid 8,
 water 23.—KLproth.  By Vauquelin's ex-
 periments it seems to contain also chrome,
 magnesia, silica,  alumina, and lime; zinc
 and lead are likewise occasionally present.
 It belongs to a recent formation ; Werner's
 ingenious theory of which is given by Pro-
 fessor Jameson, vol. xiii. p. 247. It is found
 in  the Highlands  of Scotland, in  Saxony,
 &c.  The second is  most easily reduced,
 and aflbrds the best iron.
   Pitchy  iron-ore  may also be placed here.
 Its  colour  is  blackish-brown.   Massive
 Glistening.  Fracture flat conchoidal. Trans-
 lucent on the  edges.  Hard.   Streak yel-
 lowish-gray.  Brittle.  Sp. gr. 3.562.  Its
 constituents are, phosphoric  acid 27, man-
 ganese 42,  oxide of iron 31.—Vauquelin.
 It oecurs near Limoges in France.
   Iron sinter.  Colour brown.  Massive and
 imitative. Glistening. Fracture flat conchoi-
 dal.  Translucent. Soft.  Brittle.   Sp. gr.
 2.4.  Its constituents are,  water 25, oxide
 of iron 67, sulphuric acid 8.—Klaproth.  It
 occurs in the galleries of old mines in Saxo-
 ny and Silesia.
   III. Iron pyrites.
   § 1. Hexahedral, or common iron pyrites.
 Colour  perfect bronze-yellow.   Massive,
• imitative, and crystallized; in  cubes,  vari-
 ously bevelled.   Lustre from specular-
 splendent, to glistening, and metallic. Cleav-
 age, hexahedral.  Fracture uneven.  Harder
 than feldspar, but softer than quartz.  Brit-
 tle.  When rubbed  it emits a strong sul-
 phureous smell.   Sp. gr. 4.7to 5.   It bums
 with a bluish flame, and sulphureous odour
 before the blow-pipe. It afterwards changes
 into a brownish-coloured globule, which is
 attractible by the  magnet.  Its constituents
 are,  sulpi.ur  52.5,  iron  47.5.—Hatchett.
 Silver and gold are occasionally present.  It
 occurs in beds in various mountains.  It is
 worked for  sulphur or copperas.
   §2. Prismatic iron pyrites.
   a. Radiated pyrites.   Colour pale bronze-
 yellow.   Mpst usually imitative,  or crystal-
 lized.  Primitive  form  is an oblique  four-
 sided prism, in which  the obtuse angle is
 106w 3&.  Secondary forms are the above
 variously bevelled; and the  wedge-shaped 
ORE                                   ORE
double  four-sided pyramid.   Harder than
feldspar.  Sp. gr. 4.7 to 5.0.  lis constitu-
ents are, sulphur 53.6,  iron -It), k—Huichrtt.
It is much rarer than the preceding. -It is
found in Cornwall, Isle of sheppy, Ui.  .
  b Hepatic,  or  liver pyrites.  Colour pale
brass-yellow.  Massive and imitative. Glim-
mering and metalhc.  Fracture even.   Sp.
gr. 4.834.   It occurs in veins in primitive
rocks.   It is found in Derbyshire, i^c.
  c.  Cellular pyrites. Colour bronze-;, ellow.
Cellular.  '.Surface of the culls drusy. Frac-
ture flat conchoidal.  It  occurs in veins at
Johanitfgeorgt-u.sta.dt in Saxony.
  d. Spear pyrites.  Colour between bronze-
yellow and steel-gray.   Crystallized in twin
or triple crystals.  Fracture uneven.  It oc-
curs in veins in  primitive rocks, associated
with brown coal.
  d. Cockscomb  pyrites.   Colour as above.
Crystallized in double four-sided pyramids.
Glistening and metallic.  It occurs in Der-
byshire.
  § 3.  Rhomboidal iron pyrites, or magnetic
pyrites.
  a. Foliated magnetic.   Colour  between
bronze-yellow  and  copper-red.  Massive,
and sometimes crystallized, in a regular six-
sided prism, truncated; and in a six-sided
pyramid.  Splendent and metallic.   Sp. gr.
4.4 to 4.6.   It occurs in Saxony.
  b. Compact magnetic. Same colour. Mas-
sive.  It affects the magnetic needle.   Its
constituents are, sulphur 36.5, iron 63.5.—
Hatchett.  It is found in Galloway and Caer-
narvonshire.
  IV. Native salts of iron.
   a. The Prismatic chrome-ore.  Colour be-
tween steel-gray and iron-black.  Massive,
and  in  oblique four-sided prisms,  acumina-
ted with four planes. Lustre imperfect me-
tallic.    Fracture  small  grained  uneven.
Opaque.   Hardness, between apatite  and
feldspar.  Streak dark brown.  Sp. gr. 4.4
to 4.5.  Some varieties are magnetic, others
not.  It is infusible before the blow-pipe.
'With  borax, it forms a  beautiful green-
coloured mass.   The  constituents of the
French  are, oxide  of iron 3417,  oxide of
chrome 43, alumina 20.3, silica 2,—Havy.
'The Siberian contains 34 oxide of iron, 5J
oxide of chrome, 11 alumina, 1 silica, and 1
manganese.—Laugier.   It occurs in primi-
tive serpentine.  It is found in the islands of
I'nst and Fetlar,  in Scotland; and also at
Portsoy in Banffshire. In considerable quan-
tity in serpentine on the Bare-hills near Bal-
timore.
   6  Sparry iron, ot carbonate of iron.  Co-
lour  pale  yellowish-gray.   Massive,  dis-
seminated, and crystallised.  The nrimitive
form is a rhomboid of 10."".  The fallowing
are some ofthe  secondary forms :—the pri-
mitive rhomboid, perfect or truncated; a
still flatter rhomboid; the spherical lenticu-
lar form; the saddle-;!..'mci h-tis; the eqni-
   Vol. II.
angular six-sided  prism.  Glistening  and
pearly.  Cleavage threefold.  Fracture fo-
liated. Translucenton the edges, or opaque.
Streak white or yellowish-brown.   Harder
than calcareous spar.  Sp. gr. 3.6 to 3.9.  It
blackens, and becomes magnetic before the
blow-pipe.   It  effervesces  with  muriatic
acid.  Its  constituents are, oxide  of  iron
57.5, carbonic acid 36, oxide ofmanganese
3.5, lime 1.25.—Klaproth.  It occurs in veins
in granite, and in limestone. In small quan-
tities in  Britain.   In great  quantity  at
Sclunalkalden in Hcssia.   It affords an iron
well suited for making steel.
  c.  Rhomboidal vilrwl,  or green  vitriol.
Colour  emerald-green.   Primitive form of
the crystals  is a rhomboid, with edges  of
81° 23' and 98° 37';  and plane angles  of
100° 10/ and 79° 50'. Vitreous or pearly
lustre.  Cleavage threefold.  Fracture flat
conchoidal.  Semi-transparent.   Refracts
double.  As hard as gypsum.   Sp. gr. 1.9
to 2.0.  Taste  sweetish,  styptic, and  me-
tallic.   Before the blow-pipe, on charcoal,
it becomes magnetic.  Its constituents are,
oxide of iron 25.7, sulphuric acid 28.9, wa-
ter 45.4.—Berzelius.  It  results  from  the
decomposition of'iron pyrites.
  d. Arseniate bfiron.  See Cube Ore.
  e. Blue won, or phosphate of iron.
  Prismatic blue iron.
  § 1. Foliated blue iron.  Colour dark  in-
digo-blue.  Primitive form an oblique  four-
sided prism.  The secondary forms are, a
broad rectangular  four-sided prism, trun-
cated ;  and an eight-sided prism.  Shining.
Cleavage  straight, single. Translucent.  As
hard as gypsum.  Streak, paler blue.  Sec-
tile, and easily  frangible.  Flexible in thin
pieces.  Sp. gr. 2.8 to 3.0.  Its constituents
are, oxide  of  iron 41.25, phosphoric acid
19.25,  water 31.25,  iron-shot silica  1.25,
alumina 5.— Fourcroy and Laugier. It oc-
curs in St. Agnes's in Cornwall.
   § 2.  Fibrous  blue  iron.  Colour  indigo-
blue.   Massive, and in delicate fibrous con-
cretions.   Glimmering and silky.  Opaque.
Soft.   It  occurs in syenite  at Stavern in
Norway.
   § 3.  Earthy blue  iron.   Colour as above.
Friable, and in dusty particles.  Soils slight-
ly.  Rather light.  Before the blow-pipe it
loses its  blue   colour,  becomes  reddish-
brown, and lastly,  melts into a black co-
loured  slag, attractible by the magnet.  Its
constituents are, oxide of iron 47, phospho-
ric acid 32, water 20.—Klaproth.   It occurs
in  nests  in  day-beds  In several of the
Shetland  islands,  and in river mud at Tox-
teth, near Liverpool.
  4.  TungsU'.te of iron. See Ores of Tung-
sten.
  5.  B'iie  ironstone.   Colour  indigo-blue.
Massive, and with impressions of crystals pf
brown  iron ore.   Glimmering,  or  dull.
Fnrtuiv coal's^ grained-uneven.  Opaque. 
ORE
ORE
Semi-hard.   Rather brittle.  Sp. gr. 3.'.'.—
Klaproth.  It loses its colour by heat; and
with borax forms a clear bead.   Its consti-
tuents are, oxide of iron 40.5, silica 50, lime
1.5, natron 6, water 3.  It occurs on the
banks of the  Orange River in >outhern
Africa.
  X.—Lead Ores.
  1. Galena or lead-glance.
  Hexahedral galena.
  § 1. Common.   Colour  fresh  lead-gray.
Massive, imitative, and crystallized in cubes,
octahedrons, rectangular four-sided prisms,
broad  unequiangular  six-sided prisms, six-
sided tables, and three-sided tables. Specu-
lar  splendent, to glimmering.  Lustre me-
tallic.  Cleavage hexahedral.   Fragments
cubical.  Harder than gypsum.  Sectile and
frangible.  Sp.  gr.  7. to 7.6.   Before the
blow-pipe itflies in pieces, then melts, emit-
ting a sulphureous odour, while a globule
of lead remains.  Its constituents are, lead
83, sulphur  16.41,  silver 0.08.— Westi-umb.
It occurs in beds, &c.  in various mountain
rocks.  At Leadhills  in Lanarkshire, &c.
Nearly all the lead of commerce is obtain-
ed from galena.  The  ore is  roasted and
then reduced with turf.
  § 2.  Compact galena.  Colour somewhat
darker than the preceding.  Massive, shin-
ing, metallic.  Fracture   flat  conchoidal.
Streak more  brilliant. It consists of sul-
phuret of lead, sulphuret of antimony, and
a small  portion of silver. It is found at
Leadhills in Lanarkshire, in Derbyshire, &c.
  § 3.  Friable galena. Colour dark  fresh
lead-gray. Massive and in thick flakes. Sec-
tile. It is found only around Freyberg.
  Blue lead.  Colour  between very dark
indigo-blue and dark lead-gray.   Massive,
and crystallized in regular  six sided prisms.
Feebly glimmering.   Soft.   Sectile.  Sp.
gr.  5.461. It is conjectured  to be sulphu-
ret of lead,  intermixed with phosphate of
lead.   It occurs in veins. It has been found
in Saxony and France.
  Cobaltic galena.   Colour fresh lead-gray.
Minutely disseminating in exceedingly small
crystals,  aggregated in  a moss-like  form.
Shining  and  metallic.   Scaly foliated.
Opaque.  Soft.  Soils feebly.   It  commu-
nicates a smalt-blue  colour to glass of bo-
rax.  It occurs near Clausthal in the Hartz.
  2. Lead spar,
  § 1.  Tri-prismatic lead spar, or sulphate of
lead.  Colours yellowish and grayish-white.
Massive and  crystallized.   In the primitive
form the vertical prism is 120°.   The prin-
cipal  crystallizations  are, an oblique four-
sided prism, variously bevelled or truncated;
and a broad rectangular four-sided pyramid.
Lustre shining, adamantine.  Fracture con-
ehoidal.  Translucent.  As hard as calca-
reous spar.   Streak white. Brittle. Sp. gr.
6.3. It decrepitates before the blow-pipe,
then melts, and is soon reduced to theme-
taHic state.  Its constituents arc, oxide of
lead 70.5, sulphuric acid  25.75, water 2.25.
— Klaproth.  It occurs in veins along with
galena at A\ anlockhcad in Dumfries-shire,
Leadhills, Pary's mine, and Penzance.
  § 2. Pyramidal lead spar,  or yellow lead
spar.  Colour wax-yellow.   Massive,  cel-
lular, and crystallized. Its primitive form is
a pyramid, in which the angles are 99" 40'
and  131° 45'.  Its secondary  forms are, the
pyramid variously truncated,  on the angle-
and summits, and a regular eight-sided ta-
ble.   Lustre resinous.  Cleavage fourfold.
Fracture  uneven.  Translucent.   As hard
as calcareous spar.   Brittle.   Sp. gr. 6.5 to
6.8.—Moh.i.  (5.706, Hatchett J.  Its con-
stituents are, oxide of lead 58.4, molvbdic
acid 38,  oxide  of iron 2.08,  silica 0.28.—
Hatchett. It occurs at  Bleiberg in Carinthia,
  § 3. Prismatic lead spar, or red lead spar.
Colour hyacinth-red.  Crystallized, in long
slightly oblique four-sided prisms, variously
bevelled, acuminated or  truncated.  Splen-
dent, adamantine. Fracture uneven. Trans-
lucent.   Streak between lemon-yellow and
orange-yellow.  Harder than gypsum. Sec-
tile.   Easily frangible.  Sp.gr. 6.0 to 6.1.
Before the blow-pipe it crackles  and melt-*
into a gray slag.  It does not effervesce with
acids.  Its constituents  are, oxide of lead
63.96, chromic acid 36.4.— Vauquelin.   It
occurs in veins in gneiss in the gold mines
of Beresofsk in Siberia.
  § 4. Rhomboidal lead spar•>
  a. Green lead spar.   Colour, grass-green.
Imitative or crystallized. The  primitive
form is a di-rhoraboid, or a flat equiangular
double six-sided  pyramid. The  secondary
forms are, the equiangular six-sided prism,
variously truncated and acuminated.  Splen-
dent. Fracture uneven. Translucent. Some-
times as hard as fluor. Brittle.  Sp. gr. 6 9
to 7.2. It dissolves in acids without efferves-
cence. Its constituents are, oxide of lead 80,
phosphoric acid  18, muriatic acid 162, ox-
ide  of iron, a trace.—Klaproth.   It occurs
along with galena  at Leadhills,  and Wan-
Iockhead; at Alston  in Cumberland, &c.
  b.  Brown lead spar. Colour, clove-brown.
Massive and crystallized; in an equiangular
six-sided prism;  and an acute double three-
sidedpyramid. Glistening, resinous.  Feebly
translucent. Streak grayish-white. Brittle
Sp. gr. 6.91. It melts before the blow-pipe,
and  during cooling,  shoots   into  acicular
crystals. It dissolves without effervescence
in nitric  acid. Its constituents are, oxide ol
lead 78.58, phosp'horic acid 19.73, muriatic
acid 1.65.   It occurs  in veins that traverse
gneiss.   It is found at Miess  in Bohemia.
  § 5. Di-prismatic lead spari
  a.  White lead spar.  Carbonate of  lead
Colour, white. Massive and crystallized; in
a very oblique four-sided prism ; an unequi-
angular six-sided prism ;  acute double  six-
sjded pyramid; oblique  double  four-sided 
ORE
ORE
pyramid; long'acicular crystals; and in twin
and triple  crystals.  Lustre, adamantine.
Fracture  small  conchoidal.  'Translucent.
Refracts double in a high degree.  Harder
than calcareous spar. Brittle. Sp. gr. 6.2 to
6.61 It dissolves  with effervescence in muri-
atic and nitric acids.   It yields  a metallic
globule v\ ith the blow-pipe.  Us constituents
are, oxide of lead 82, carbonic acid 16, water
2.—Klaproth.  It occurs in veins at Lead-
hills in Lanarkshire.
  b. Black lead spar. Colour, grayish-bjack.
Massive, cellular and seldom crystallized, in
very small six-sided prisms.  Splendent, me-
tallo-adamantine. Fracture uneven.  Streak
whitish-gray.  Its constituents are, oxide qf
lead 79, carbonic acid 18, carbon 2.—Lam-
padius. It occurs in the  upper part of veins,
at Leadhills, &c.
  c. Earthy lead spar.   Colour, yellowish-
gray.   Massive.    Glimmering.   Opaque.
Streak, brown.  Very soft.  Sp.  gr.  5.579.
Its  constituents are, oxide  of lead 66, car-
bonic  acid  12,  water 2.25, silica 10.5, alu-
mina 4.75, iron and oxide ofmanganese 2.25.
—John.  It is  found at Wanlockhead.
  Corneous  lead ore, or vmriate of lead.
Colour, grayish-white.   Crystallized, in an
oblique  four-sided  prism,  variously trun-
cated, bevelled, and acuminated. Splendent
and adamantine. Cleavage threefold. Frac-
ture conchoidal.  Transparent. Soft. Sec-
tile and easily frangible.  Sp. gr.  6.065.  It
melts into an orange-coloured globule.  Its
constituents are, oxide of lead 85.5, muriatic
acid 8.5, carbonic acid  6.—Klaproth.  It is
found  in  Cromford-level near Matlock in
Derbyshire.
  Arseniate of lead.
  § I.  Reniform.  Colour  reddish-brown.
Shining.  Fracture  conchoidal.   Opaque.
Soft and brittle.  Sp. gr. 3.933.   It gives
out arsenical vapours with the blow-pipe.
It colours glass of borax lemon-yellow.  Its
constituents are, oxide  of lead 35, arsenic
acid 25, water 10, oxide of  iron  14,  silver
1.15, silica 7, alumina 2. Itis found in Siberia.
  § 2.  Filamentous.  Colours, green or yel-
low. In acicular six-sided prisms, orin silky
fibres.  Slightly flexible and easily frangable
Sp. gr. 5.0 to 6.4.  Its constituents  are,  ox-
ide  of lead 69.76, arsenic acid 26.4, muriatic
acid 1.58.— Gregor.  It occurs in  Cornwall.
  § 3.  Earthy  arseniate.   Colour, yellow.  In
crusts.  Friable.  It occurs at St. Prix in
France.
  Native nrinium.  Colour scarlet-red. Mas-
sive, amorphous, and pulverulent.  It is found
in Grassington-moor, Craven. Mr. Smithson
thinks  this mineral is produced by the de-
cay of galena or lead-glance.
  XI.—Mangami.se Ores.
  1. Prismatic manganese ore.
  § 1.   Gray manganese ore.
  a. Fibrous gray manganese ore.   Colour,
dark steel-gray.  Massive, imitative, and in
very delicate acicular crystals, and in thin
and  long  rectangular   four-sided tables.
Shining and splendent. Soils strongly. Soft.
Brittle.  It occuis in the Westerwald
  b. Radiated.   Colour,  dark  steel-gray.
Massive, imitative, ami  crystallized.   The
primitive form  is an  oblique four-sided
prism, in which the largest angle is about
100°.  Secondary forms are, the primitive
bevelled, or acuminated, or spicular crys-
tals. Cleavage prismatic. Streak dull black.
Soils.  Soft.  Brittle.  Sp.  gr. 4.4 to 4.8.
Shining and metallic.  Its constituents are,
black oxide ofmanganese 90.5, oxygen 2.25,
water 7. -Klaproth.   It  occurs in the  vici-
nity of Aberdeen, in Cornwall, Devonshire,
&c.
  c. Foliated.   Colour between steel-gray
and iron-black   Massive and crystallized in
short oblique  four-sided prisms.  Shining,
metallic. Cleavage prismatic.  Fracture un-
even.  Other characters, as above.  Sp. gr.
3.742. It is found in Devonshire.
  d. Compact.  Fracture even, or flat con-
choidal.  Sp. gr. 4. to 4.4.  Other charac-
ters as preceding. Its constituents are, yel-
low  oxide ofmanganese? 50,  oxygen 33,
barytes 14, silica 1 to 6.   Analysis doubtful.
It occurs at Upton Pyne in Devonshire.
  e. Earthy.  Friable.  It consists  of semi-
metallic fecbky glimmering fine scaly parti-
cles, which soil strongly.  It occurs in  the
mine  Johannis in the Erzegebirge. It tin-
ges borax purple ; and effervesces with mu-
riatic acid,  giving out chlorine.  These five
kinds occur in granite, gneiss, &c. either in
veins or in  large cotemporaneous masses.
  § 2.  Black manganese ore.
  a. Compact.   Colour,  between bluish-
black  and steel-gray.  Massive, imitative,
and in curved lamellar concretions. Glim-
mering and imperfect metallic lustre. Frac-
ture conchoidal.  Streak shining,  with co-
lour unchanged. Semi-hard. Brittle. Sp. gr.
4.75.
  b.  Fibrous.  Massive,  imitative,  and  in
delicate scopiform concretions.  Fragments
cuneiform and splintery.  Its other charac-
ters as above.  It yields a violet-blue glass
with borax. It occurs in veins in the Erze-
gebirge. It yields a good iron;  but acts very
powerfully on the sides of the furnace.  It
is called black hematite.
  c.  Foliated. Colour brownish-black. Crys-
tallized  sometimes in acute double  four-
sided pyramids.   Shining.   Cleavage  sin-
gle, and curved foliated.  Streak dark  red,
dish-brown. Brittle.  It is supposed to con-
sist of iron  and manganese.
  § 3.  Scaly brown manganese ore.   Colour
between steel-gray and clove-brown.  In
crusts.  Massive  and  imitative.   Friable.
Composed  of shining scaly particles. Soils
strongly.  Feels greasy.  It gives to glass
of borax, an olive-green  colour.  It occurs
in drusy  caviti%s  in brown hematite.  It is 
ORE                                    ORE
found near Sandlodge in Mainland, one of
the Shetlands.
  4. Mang\inese-blende.
  Prismatic.  Colour, iron-black.  Massive,
in distinct concretions, and sometimes crys-
tallized.   Primitive form, an oblique four-
sided prism, which becomes variously riiodi-
fied by truncations on  the lateral edges.
Lustre splendent, and semi-metallic. Streak
greenish.   Harder  than  calcareous  spar.
Easily frangible.  Before  the  blow-pipe  it
gives out sulphur, and tinges borax violet-
blue.  Its constituents are, oxide of manga-
nese  82, sulphur 11.5, carbonic acid 5.—
Klaproth.   Oxide ofmanganese  85, sulphur
15.— Vauquelin.  It is found in Cornwall.
  5.  Phosphate  of  manganese.   Colour,
brownish-black.  Massive and disseminated.
Glistening. Fracture  flat conchoidal. Semi-
transparent, in splinters.   Scratches  glass.
Streak yellowish-gray.  Brittle.  Sp. gr. 3.5
to 3.7.  It is fusible into a black  enamel.
Its constituents are, oxide ofmanganese 42,
oxide of iron  31, phosphoric acid 27.   It
occurs in a coarse granular granite at Li-
moges in  France.
  6. 'Rhomboidal red manganese.
  a.  Foliated.   Colour,  bright  rose-red.
Massive, imitative, and crystallized in rhom-
boids.  Shining,  pearly.   Cleavage rhom-
boidal.   Translucent on the edges.   Hard-
ness  between  fluor  and  cwlcareous spar.
Brittle.  Sp. gr. 3.3 to  3.6.   Before  the
blow-pipe it first becomes dark brown, and
then melts into a reddish-brown bead.   Its
constituents are,  oxide of manganese 52.6,
silica 39.6, osjide of iron 4.6, lime 1.5, vola-
tile ingredients 2.7.5.— Berzelius.  U. occurs
in beds of specular iron ore in gneiss hil's'm
Sweden and Siberia. The specimens of the
latter are cut into ornamental stones.
   h. Fibrous.   Colours, rose-red and fiVsb-
rcd.  Massive  and in  distinct  prismatic fi-
brous concretions.   Glistening ami pcaily.
 Fragments splintery.  Feebly  franslrcent.
 It occurs in Transv Ivania and Hunuiiy.
   c.  Compact.  Colour, pale rose-rid.   Mas-
 sive or reniform.   Glimmering".   Sp. gr. 3.3
 to 3.9.   Its constituents are, .oxide of man-
 ganese 61, silica 30, oxide ot* iron 5,  a'umi-
 na  2.—Lampad.   It occurs at Kapnik  in
  Transylvania.
   Pitchy iro-i  ore  may be regarded  as a
 phosphate ofmanganese.
   XI f. Mi act -ry -Ores.
   1. Native mercury.
   a. Fluid mercury.   See Mr.m-irnv.    It
 occurs principally in rocks of  the coal for-
 mation, associated with cinnabar, corneous
 mercury, 8tc.  Small veins of it are rarely
  met with in primitive  rocks,  accompanied
  with native silver, &c.   It is found at klria,
 in the Friaul; Niderslana in Upper Hunga-
  ry ;  in the Palatinate;  Deux-Ponts,  &.e.
    b. D u!-•■:<;'xctral mercury, w native amal-
  gam.
  $.  1. Fluid,  or  semi-flidil 'amalg.i'n.  Co-
lour tin-white.  In roundish portions; and
crystallized, in a rliomboklal dodecahedron,
rarely perfect. Splendent.   When  cut, it
emits a creaking sound.  As hard as  talc.
Sp- gr. 10.5.  Its constituents are, mercury
74, silver 25.  It is found at Deux-Toms.
 ' ^2.  Solid amalgam.  Colour, silver-white.
Massive  and  thsseminaed.  Fracture flat
conchoidal.  As hard as gypsum.  Brittle.
Creaks strongly when  cut.  Sp. gr.  10.5.
The mercury flies ol; before the blow-pipe.
Its constituents are, mercury 74, silver 25,
—Heye•:  Mercury  64, silver  36.— Klap-
roth.  It is found  in Hungary, the Deux-
Ponts, &c.
   2. Cinnabar, or prismato-rhomboidal ruby-
blende.
   <i. Dark redchviahar.  Colour cochincal-
red.  Massive, disseminated, imitative, and
crystallized.  Primitive form a rhomboid.
Secondary forms; a regular six-sided prism,
an  acute  rhomboid and a  six-sided ta-
ble. Splendent, adamantine. Translucent.
Streak  scarlet-red,  shining.  Harder  than
gypsum.   Sectile and easily frangible.  Sp.
gr. 6.7 to 8.2.  It  melts, and is volatilized
with a blue flame, and  sulphureous odour.
Its constituents are, mercury 84.5, sulphur
14.75.— Klaproth.
   b. Briqht  red  cinnabar.   Colour bright
scarlet-red. Massive, and in delicate fibrous
concretions. Glimmering and pearly. Frac-
ture earthy.  Opaque.  Mreak,  shining.
 Soils.   Friable.   It occurs in rocks of clay-
slate, talc-slate, and ctilorite-slate ; in veins
at Horzowitz in Bohemia; at Jdria, &c.
   c. Hepatic cinnabar.
   §1. Compact. Colour between cochineal.
 red and dark lead-gray   Massive.  Glim-
 mering and semi-metallic.  Streak shining.
 Opaque.  Soft-   Sectile.  Sp. gr. 7.2.  Its
 constituents  are,  mercury  81.S,  sulphur
 13 75,  carbon  2.3,  silica  0.65,  alumina
 0 55, oxide of iron 0.2, copper 0.02, water
 0.73.
   § 2. Slaty  mercurial  hepatic  ore.  Colour
 as above, but  sometimes  approaching to
 black.  Massive, and  in roundish  concre-
 tions.   Lustre shining,  semi-metallic.  Frac-
 ture curved  slaty.  Most  easily  frangible.
 Streak  cochineal-red, inclining to brown.
 Rather lighter than the compact. It occurs
 in considerable masses in slate-clay and bi-
 tuminous shale.   It is  most abundant in
 Idria.
    3. Corneous mercury, or htm quicksilver.
    Pyramidal  corneous  mercury.   Colour
 ush-giay.   Vesicular, with interior crystalli-
 zations; which are, a rectangular four-sided
 prism, variously  acuminated, and a double
 four-sided pyramid.  Crystals very minute.
 shining,  adamantine.    Cleavage,  single.
 Faintly translucent. Moft. sectile and easily
 frangible.  It is totally  volatilized before the
 blow-pipe, with a gariic smell.  It is soluble 
ORE
ORE
in water, and the sdution mixed with lime-
water, gives an orange-coloured precipitate.
Its constituents are, oxide of mercury 76,
muriatic acid  16.4, sulphuric acid 7-6—
Klaproth.  It occurs in  Bohemia, Stc.
  X'li.— Molybdena Ores.
  Rhomboidal molybdena.  Colour fresh lead-
gray.  Massive, in  plates,  and sometimes
crv stalhzed.  Primitive form  is  a rhom-
boid.  Secondary figures are, a regular six-
sided table, and a very short six-sided prism,
flatly  acuminated  on both   extremities.
Splendent,  metallic.  Cleavage single.  O-
paque.   Streak on paper,  bluish-gray ; on
porcelain,  greenish gray.   Soils  slightly.
Harder than talc.   Easily frangible.   :splits
easily.  In  thin, leaves flexible,  but not elas-
tic.   Sectile,  approaching to malleable.
 Feels greasy.  Sp. gr. 4.4 to 4.6.  It  emits
 a sulphureous odour before the blow-pipe.
 It is soluble, with violent effervescence, in
 carbonate  of soda.  Its constituents are,
 molybdena 60,  sulphur 40.—Bucholz.  It
 occurs disseminated in granite, gneiss,  &c.
 It is found in Glenelg in Inverness-shire, at
 Peterhead, at Cory buy at the head of Loch
 Crcran, in Cornwall,  &c.
   Molybdena ochre. Colour sulphur-yellow.
 Disseminated and incrusting molybdena.
 Friable ;  dull.  In Corybuy and Norway.
   For molybdate of lead,  see Lead Ores.
   XIV—Nickel Ores.
   1. Native  nickel.   Colour  brass-yelldw.
 In delicate capilla/y crystals.   Shining  and
 metallic.   Crystals rigid.  Brittle.  It con-
 sists, according to Klaproth, of nickel, with
 a small quantity  of cobalt and arsenic.  It
 occurs in veins is gneiss, in Saxony.
   2. JKickel pyrites, or copper nickel.
   Prismatic nickel pyrites.   Colour copper-
 red, becomingblack.  Massive,disseminated,
 imitative,  and crystallized, in oblique four-
 sided  prisms.   Shining, metallic.  Harder
 than apatite.  Rather difficultly  frangible.
  So. gr.  7.5 to 7.7   It emits an arsenical
  vapour before the blow-pipe, and then fuses
  into a  dark  scoria,  mixed  with metallic
  grains.  It yields a dark green solution with
  nitro-muriatic acid.   Its  constituents  are
  nickel and arsenic, with accidental  admix-
  tures of cobalt,  iron, and sulphur.  It gene-
  rally occurs in primitive rocks.   It is found
  in  small  quantities at Leadhills  and VVan-
  lockhead, and  in  the coal field of Linlith-
  gowshire.
    Black nickel.   Colour dark grayish-black.
  Massive, and in crusts.  Dull.  Earthy frac-
  ture.  Soft.  Streak shining.   Soils slightly.
  It  forms an apple-green  coloured solution
  with nitric acid, which lets fall a white pre-
  cipitate with  arsenic acid.   It  occurs  in
  veins that traverse   bituminous  marl-slate
  at Riegelsdorf.
     Nickel ochre.  Colour apple-green.  In an
  efflorescence.   Dull.   Fracture  splintery.
  Soft.   Feels meagre.   It gives to glass of
  borax a  hyacjnth-red colour.  It occurs at
Leadhills, at Alva in Stirlingshire, and  in
Saxony.   It consists of oxide of nickel 67,
oxide of  iron 23.2, water 1.5, loss 8.3.—
LampadivH.
  X\'.— Pallaihum Ohe.
  Native palladium.  < dour pale steel-gray,
passing into slv, r-vvhne.  It occurs in small
grains.   Lustre metallic.  Fracture diverg-
ing fibrous. Opaque. Sp. gr. 11.8 to 12.148.
It is infusible, but on  the addition of sul-
phur, it melts. It forms a deep red solution
with nitric acid.   It consists of palladium,
alloyed with a minute portion of platina and
iridium.   It is found in  grains along with
grains, of native platina, in the alluvial gold
districts in Brazil.— Wollaston.
   XVI.—Platina Ore.  Colour very light
 steel-gray. In flat small grains. Shining and
 metallic.  Nearly as hard as iron.  Malleable.
 sp. gr. 17.7.  it  is found in the gray silver
 ore of Guadalcanal in  Spain, in Choco, in
 New Granada, and in the province of Bar-
 bacoas.  It  is peculiar to an alluvial tract
 of 600 It agues,  where it is associated  with
 grams of native gold, zircon, spinel, quartz,
 and magnetic ironstone.  It is not true, that
 this metal occurs near Carthagena, or Santa
 Fe, or in the islands  of Porto  Rico and
 Barbadoes,  or in  Peru,  although these dif-
 ferent localities are mentioned by authors.
 'The gray copper ore of Guadalcanal in Spain
 contains from 1 to 10 per cent, of platina.
   XVII.—Silver Ores.
    1. Hexahedral, or native silver.
    a. Common native silver.  Colour  pure
 silver-white.   Disseminated, in  plates or
 membranes, imitative, and crystallized; in a
 cube; octohedron; tetrahedron; rhomboidal
 dodecahedron;  leucite form; and six-sided
 table.   Crystals microscopic.   Shining and
  metallic.  Fracture fine hackly.   Streak
  splendent.  Harder than  gold,  tin, lead;
  but softer  than iron,  platina, and copper.
  Perfectly malleable. Flexible, and difficultly
  frangible.   Sp. gr.  10 to 10.4.   Its consti-
  tuents arc, metallic silver 99, metallic anti-
  mony 1, with a trace of copper and arsemc.
  —John.   It occurs  principally  in  veins in
  primitive  mountains.   In  granite in  the
  Erzegebhge.   In gneiss and mica-slate in
  Saxony, Bohemia, and Norway.   In clay-
  slatc in Irdand.   In clay-porphyry,at Alva,
  in the < ichil Hills, Stirlingshire.  For a co-
  pious list of localities, see Jameson's Miner-
  alogy.
     b. .'Iriferous  native' silver.   Colour  be-
  tween  hi iss-yellow and silver-white.  Dis-
  seminated, in membranes, and crystallized in
  cubes.  Its sp. gr. is greater than that ofthe
  preceding.  Its constituents are, silver 72,
  gold  28.— fWdyre.   It occurs in veins in
  primitive rocks at Kongsberg in Norway.
     2.  Silver-glance, or vitreous silver.
     § 1.  Hexhahedral.
     a.  Compact.   Colour dark blackish lead-
  gray.   Massive, imitative, and crystallized;
  in, a cube, octahedron, rhomboidal dodeca- , 
ORE                                   ORE
  hedron,  and  double eight-sided pyramid.
  Glistening, metallic. Cleavage rhomboidal.
  Harder than gypsum.  Completely mallea-
  ble. Flexible, but not elastic.  Difficultly
  frangible.   Sp. gr. 5.7 to 6.1.  Before the
  blow-pipe it loses its sulphur, and a bead of
  pure silver remains. Its constituents are,
  silver 85, sulphur 15__Klaproth.  It  is one
  ofthe most frequent of the ores of silver.
  It occurs in mica slate, clay-slate, graywacke,
  and seldomer in granite. It is found in Corn-
  wall.
    b. Earthy. Colour bluish-black. In crusts.
  Friable or solid.  Dull.  Feebly translucent.
  Streak  shining,  metallic.  Soils  a  little.
  Easily frangible.  Sectile.  It is easily fused
  by the blow-pipe. It is a sulphuret of silver.
    § 2.  Rhomboidal silver-glance. Colour be-
  tween  iron-black and  blackish lead-gray.
  Crystallized.  Primitive form, a rhomboid.
  Secondary figures; an equiangular six-sided
  prism,  ah equiangular six-sided table, and
  a double six-sided  pyramid.  The tabular
  crystals often intersect each other, forming
  cells. Highly splendent, and metallic. Soft.
  Sectile, Easily frangible.  Sp. gr. 5.7 to 6.1.
  It melts with difficulty.   Its constituents are
  silver 66.5,  sulphur 12, antimony 10, iron 5,
  copper and arsenic 0.5, earthy substances
  1,0.  It occurs in  gneiss, &c. It is found in
  the district of Freyberg.
    3. White silver.  Colour very  light lead-
  gray. Massive, disseminated, and always as-
  sociated  with  lead-glance.  Glistening and
  metallic.   Fracture  even.   Soft.   Sectile.
  Easily frangible.  Sp. gr. 5.3 to 5.6.  Before
  the blow-pipe  itmeltsand partly evaporates,
  leaving a bead of impure silver, surrounded
  by  a yellow powder.  Its constituents are,
  lead 41, silver 9.25, antimony 215, iron 1.75,
  sulphur 22, alumina 1, silica 0,75.—Klaproth.
  It occurs in gneiss.  It is found near  Frey-
  berg.
    4. Gray silver ot carbonate of silver.  Co-
  lour ash-gray.   Massive and disseminated.
  Glistening  Fracture uneven.  Soft. Streak
  more shining.  Brittle.   Heavy.  Easily re-
  duced before the blow-pipe.  Its constituents
  are,  silver 72.5, carbonic acid 12, oxide of
  antimony, and a trace of copper 15.5.—Selb.
  It occurs in veins that traverse granite in
  the  Black Forest.
    5. Antimonial silver.    Colour, between
  silver-white  and tin-white. Massive, dissem-
  inated,  i n distinct concretions, and crystal-
  lized;  in a  rectangular four-sided  prism,
  in an unequiangular six-sided prism, and a
  double six-sided pyramid, truncated on the
  apices.  Surface ofthe prisms, longitudinal-
  ly streaked.  Splendent, metallic Cleavage,
  octohedral.  Hardness,  between calc and
  fluorspar. Sp. gr. 9.4 to 10. The antimony
  is volatilized before the blow-pipe, and  sil-
  ver remains  on the charcoal  Its constitu-
  ents are, silver 78, antimony 22—Vauquelin.
  It occurs in veins in granite, and graywacke.
, In the first, at Altwolfach in Suabia; in clay-
 slate in the Hartz.  See Dodecahedral Ah.
 timont.
   6. Arscniral silver.  Colour on  the fresh
 surface, tin-white,  which tarnishes grayish-
 black.   Massive,  and reniform.  Fracture
 small-grained  uneven.  Harder than anti-
 monial sUver.  Streak shining.  Sectile, and
 easily frangible.   Sp. gr. 9.44.  Before the
 blow-pipe the antimony and arsenic are vo-
 latilized with  a garlic  smell;  while a glo-
 bule of silver remains, which is more or less
 pure.  Its constituents are, arsenic 35, iron
 44.25, silver 12.75, antimony 4. It general-
 ly occurs  along with native arsenic.  It is
 found in the Hartz.
   7. Bismuthic silver. Colour pale lead-gray.
 Disseminated, and rarely crystallized in oa-
 pillary crystals.   Glistening  and  metallic.
 Soft. Sectile.  Easily frangible. Its constitu-
 ents are, bismuth 27, lead 33, silver 15, iron
 4.3, copper 0.9, sulphur 16.3— Klaprotfi. It
 has  been found only in the Friedrich-Chris-
 tian Mine in the Black  Forest, in veins, in
 gneiss.
   8.  Ruby-blende.
   §  1. Rhomboidal ruby-blende.
   a.  Dark red silver.  Colour between co-
 diineal-red, and dark lead-gray.  Massive, in
 membranes, and crystallized. Prim, form, a
 rhomboid  of 109° 28'. Secondary  forms, an
 equiangular six-sided prism, variously trun-
 cated and  acuminated;  and an equiangular
 double six-sided pyramid.   Splendent and
 adamantine. Cleavage rho/nboidal.  Semi-
 transparent. Streak cochineal-red. Harder
 thangypsuih. Sectile. Easily frangible. Sp.
 gr. 5.2 to 5.7.  Before the blow-pipe, it first
 decrepitates, then melts with a slight effer-
 vescence, leaving a globule of silver.  Its
 constituents are, silver 60, antimony 20.3,
 sulphur 14.7, oxygen 5—Klaproth.   It oc-
 curs in veins in gneiss,  &c.   It is found in
 the silver mines of Kongsberg,and in those
 ofthe Hartz.
  § 2. Light red silver.  Colour cochineal-
 red.  Streak aurora-red,  passing into  cochi-
 neal-red.   Sp.  gr. 5.5 to 5.9.  In  other re-
 spects, as  preceding. Its constituents are,
 silver 54.27, antimony 16.3,  sulphur  17.75,
 oxygen 11.85.— Vauquelin. It occurs at An-
 dreasberg  in the Hartz.
  XVIII.—Tantalum Ores.
  1. Prismatic  tantalum  ore.  Columbiteof
 Hatchett.  Colours grayish  and brownish-
 black. Massive, disseminated, and crystal-
 lized in oblique four-sided prisms.   Semi-
 metallic adamantine lustre. Fracture coarse-
 grained uneven. Opaque.  As hard as feld-
 spar. Difficultly frangible.  Sp. gr.  6.0 to
 6.3.   It does not fuse with glass of borax.
 Its constituents are,
                         Wollaston.
 oxide of tantalum,      85        80
 oxide of iron,          10        15
oxide ofmanganese,     4         5
                    Finland. N.American,
                            Or Columbite. 
                   ORE

     It occurs in a coarse  red granite in Fin-
   land, and in Massachusetts Bay, in North
   America.
     2.  Yttrotantalite.  Colours iron-black and
   yellowish-brown.   Imbedded  in angular
   pieces, and  crystallized  in  oblique four-
   sided and in  six-sided prisms.   Resinous,
   metallic lustre.  Fracture conchoidal.  O-
   paque.  Scratches  glass.  Streak gray-co-
   loured. Easily frangible. Sp.gr. 5.4 to 5.88.
   It decrepitates,  but does not fus« with the
   blow-pipe.  Its  constituents are, oxide of
  tantalum  57, yttria 20.25, lime 6.25, oxide
  of iron 3.5,  oxide of uranium 0.5, tungstic
  acid 8.25. It occurs along with gadolinite in
  a bed of flesh-red feldspar in gneiss at Ytter-
  by in Sweden.
    XIX.—Tflltjrium Ores,
    1. Hexahedral or native tellurium. Colour
  tin-white.  Massive, disseminated, and  in
  rectangular four-sided  prisms, acuminated
  with four planes. Shining, metallic.  Cleav-
  age hexahedral.  As hard as gypsum. Ra-
  ther brittle.  Sp. gr. 6.1 to 6.2. It melts as
  easily as lead,  emits a thick white smoke,
  and burns with a light green cdour, and a
  pungent acrid  odour,  like that of  horse-
  radish.   Its  constituents are,  tellurium
  92.55. iron 7.2, gold 0.25.  It occurs in veins
  in graywacke, at Fatzebay, in Transylvania,
  and in Norway.
    2. Prismatic black tellurium.  Colour be-
  tween  blackish  lead-gray  and iron-black.
  Massive, in flakes, and crystallized. Primi-
  tive figure, an oblique  four-sided prism.
  Secondary forms are, an oblique four-sided
  table,  a six-sided  table,  an eight-sided
  table,  artd an acute double four-sided py-
  ramid.   Splendent  and metallic.   Frag-
  ments tabular.  Harder than talc.  Sectile.
  Soils slightly. The  thin leaves and tables
 are flexible.  Sp. gr. 7.0 to 7.2.   It melts
 very easily before the blow-pipe.  Its con-
 stituents are tellurium 32.2, lead 54, gold 9,
 sulphur 3, copper 1.3, silver 0.5.—Klaproth.
 It is worked for the gold it contains.   It is
 found at Naygag, in  Transylvania.
   3. Prismatic gold glance.
   § 1.  Graphie  gold glance,  or  tellurium.
 Colour steel-gray.  Massive, in leaves and
 crystallized.  Primitive  form,  an oblique
 four-sided  prism.   Splendent,  metallic.
 Cleavage prismatic.  Fracture fine-grained
 uneven.  As hard as gypsum. Brittle.  Soils
 slightly. Sp.gr. 5.7 to 5.8. Before the blow-
 pipe it burns with a green flame, and is vo-
 latilized. Its constituents are, tellurium 60,
 gold 30, silver 10. It  occurs in porphyry in
 'Transylvania.
   § 2.  Yellow $rold glance, of yellow telluri-
 um. Colour silver-white,  inclining to brass-
 yellow.  Disseminated and crystallized, in
four-sided acicular prisms, which  are rare.
 Splendent, metallic.   Cleavage prismatic.
 Fracture small-grained uneven  Sp. gr. 5 7
                   ORE

  to 5.8.  Its constituents are, tellurium 44.75,
  gold 26.75, lead  19.5, silver 8.5,  sulphur
  0.5.—Klaproth.   It occurs in veins in por-
  phyry at Naygag, in Transylvania.
    XX.—Tix Ores.
    1. Pyramidal tin ore.
    § 1. Common tin ore, or  tinstone.   Colour
  blackish-brown.  Massive, disseminated, but
  most frequently crystallized. Primitive form,
  a double four-sided pyramid, in which the
  angles are 163° 36' and 67" 42'. Secondary
  figures are, the primitive truncated; a rec-
  tangular  four-3ided prism, variously trun-
  cated  or acuminated,  and  twin   crystals.
  Splendent, and adamantine.  Fracture un-
  even.   From  semi-transparent  to  opaque.
  Streak  grayish-white.  As  hard as feldspar,
  sometimes as quartz.  Easily frangible.  Sp.
  gr. 6.3 to 7.0.  Before the  blow-pipe it de-
  crepitates,  and  becomes paler, and is re-
  duced to the metallic state. Its constituents
  are, tin 77 5, iron 0.25, oxygen 21.5, silica
  0.75 It occurs in granite,  gneiss, &c.;  and
  in an alluvial form, in what are in Cornwall
  called  stream works. There  are onlv three
  tin districts in Europe; Cornwall, which is
  the most considerable;  the Erzegebirge;
  and Monte Rey, in Gallicia.
   § 2.  Cornish tin ore, or wood-tin.   Colour
  hair-brown. In rolled and imitative  shapes.
  Glistening.  Opaque.   Softer than common
  tinstone.  Streak gray, inclining to brown
  Brittle.   Sp. gr. 6.4   Its constituents are,
  oxide of tin 91, oxide of iron 9.— Vauquelin.
  It occurs along with stream-tin.
   2. Tin pyrites. Colpur between steel-gray
  and brass-yellow.  Massive and disseminat-
  ed.   Glistening and metallic.  Fracture un-
 even.  Yields easily to the  knife.   Brittle.
 Sp. gr.  4.35.  Not magnetic.  Before  the
 blow-pipe it exhales a sulphureous vapour.
 and melts easily.  Its constituents  are, tin
 34, copper 36,  iron  3, sulphur 25,  earthy
 matter 2.—Klaproth.  It has been found only
 in  Cornwall, in  granite, at St. Michael's
 Mount.
   XXI.—TiTANirivt Ores.
   1. Prismatic iitanium ore, or sphenc.
   a.  Common sphene.  Colours, reddish, vel
 lowish,  and  reddish-brown.  It occurs  in
 granular concretions, and crystallized in  the
 following forms:   A low very oblique four-
 sided prism, bevelled or truncated; abroad
 six-sided prism;  a rectangular four-sided
 prism;  an oblique double four-sided pyra-
 mid.  Shining  and adamantine.  Fractute
 imperfect  conchoidal.  Streak gravish  or
 yellowish-white. Harder than  apatite. Brir
 tie.  Sp. gr. 3.4 to 3.6.  Before the blow-
 pipe it is fusible with difficulty into a brown-
ish-black enamel.  Its constituents are, ox-
ide of titanium 46, silica 36,  lime 16, water
 l.—Klaproth.  It occurs  in the syenite of
Criffle, and other hills in Galloway;  in t\:c
syenite of Inveraray;  on the south side of
Lxjch-Ness; the grani^ of AK"-r,""E- '"!.' 
                 ORE

syenite of Culloden, in Inverness-shire;  in
the  floetz  rocks of Mil-Lothian; and at
Arendal, in  Norway.
  b. Foliated sphene.  L'd.rtlr yellow.  Mas-
sive, in straight  lamellar concretions, and
crystallized  as the preceding. Lustre splen-
dent.  Cleavage double.  Fracture imper-
fect conchoidal.   I ranslucent.   It occurs
at La Portia, in Piedmont, St. Gothard, and
Arendal.
  2. Prismato-pyramidal titaniyfn ore.
  a. Rutile.  Colour  reddish-brown.  Mas-
sive and  crystallized.  Primitive figure, a
pyramid of 117«* 2' and 84° 48'.  Secondary
ibrius  are,  a long rectangular four-sided
prism; four-sided prism; six-sided prism;
and acicular crystals.   The crystals are oc-
casionally curved.  Splendent or glistening.
Streak brown.   Translucent,  Haider than
apatite.  Brittle.   Sp. gr.  4.255.—iArary.
It is pure oxide of titanium, with a little ox-
ide of iron.  It  ocelli's in  the granite  of
Cairngorm,  the limestone of Rannoch, and
in the  rocks of Ben Gloe, v. here it was dis-
covered by  Dr. M'Culloch.
  b. Iseriue.  Colour iron-black.  In obtuse
angular grains, and in rolled pieces. Splen-
dent  and  metallic.  Fracture conchoidal.
Harder than feldspar.  Opaque.  Brittle.
Sp. gr. 4.6.   Before the blow-pipe it melts
into a blackish-brown coloured glass, which
is slightly   attracted  by the magnet.   Its
constituents are,  oxide of titanium 28, oxide
of iron 72.—Klaproth; or oxide of titanium
48, oxide of iron  48,  oxide of uranium 2___
Thomson.  It  occurs  imbedded  in gneiss,
and disseminated in granite sand, along w ith
iron sand, in the bed of the river Don, in
Aberdeenshire.
  c. Menachanile.   Colour  grayish-black.
In small flattish angular grains. Glimmering
or  semi-metallic.  Opaque.  Brittle.  Sp.
^r.  4.427.   It is attractible by the magnet.
f-s  constituents are, oxide of iron 51, oxide
of titanium  45.25, oxide of manganese 0.25,
silica 3.5.—Klaproth   it is found in the val-
ley of Manachan in Cornwall.
  3. /'" amidal titanium ore, or oclohedr'Ue.
Colour passes from ^ndigo-blue to brown
f nslaHi/.ed.■ Its primitive  form is a pvra-
':T;<lof97u38'aiid  137° 10'.  The follow-
ing are secondary figures; the pyramid trun-
cated on the extremities, and double four-
vded pyramid, variously acuminated.  Lustre
splendent, adamantine.- Cleavage fourfold.
Translucent.  Harder than apaike  livitilc.
s'p. gr. 3.8 to 3.9.  It is oxide of Titanium.
It is found in-Daiipiiiuy.
  XXII—Ti m.stkv  Okes.
  1. Pyviinii Jul tungsten, or sclwclium.  Co-
lour v. liite.   Massive, and sometimes crys-
biMiz-d. 'The primitive form is a rather acute
rT/irM ?  four-sided  pj ramid.    Secondary
forms are ;  the nriu^tive figure bevelled on
rtie angles;  a very acute double  four-sided
;■• r i :>'. 1:  .i  f'-<:- double t'u-ir- ,ided nv ru-rnid ;
                 ORE

a square lenticular figure ; and a flat douni;
four-sided  pyramid.   Hiining.   Fracture
uneven.  Cleavage  ninefold   Translucent.
Harder than fluor spar   Brittle,  sp  gr.
6  to 6.1.   Its  constituents are,  oxide of
tungsten 65,  lime  31, silica  4.—Scheelc;
oxide of tungsten 75.25, lime 18."u,  silica
1.56, oxide of iron 1 25, oxide of manganese
0.75__Klaproth.  It occurs along with  tin-
stone and wolfram, in Cornwall; in Sweden,
Saxony, &c.
  2. Wolfram.
  Prismatic wolfram.   Colour black.  Ma-
sive and crystallized.   Primitive  form is an
oblique four-sided prism of 120°.  Second-
ary forms are ; the oblique four-sided prism,
bevelled, truncated or acuminated;  and a
twin crystal.   Shining   Fracture uneven.
Opaque.   Streak dark reddish-brown. Bar-
der than apatite   Brittle.  Sp. gr.  7.1  to
7 4.  Its constituents are, tungstic acid 67,
oxide  of manganese  6.25, oxide of iron
18.10, silica 1.5—Vauquelin.   It  occurs in
gneiss in the island  of Ron a ofthe Hebrides^
and  in Cornwall.
  XXIII.-Uranium Ores.
  1. Uran ochre.
  a. Friable.  Colour lemon-yellow.  Hoc-
curs as a coating on pitch ore.  It is com-
posed of dull, weakly cohering particles. It
feels meagre.
  ■b. Indurated.   Colour straw-yellow. Mis-
sive  and   superimposed.    Glimmering.
Opaque.   Soft.   Sp.  gr.  3.15.  The yol-
low varieties are  pure oxide of uranium.
The brownish and  reddish contain  a little
iron.  It is found in Bohemia and Saxony.
  2. Indivisible uranium,  or pitch ore.  Co-
lour greenish-black.  Massive, reniform and
in distinct concretions.  Shining. Hardness
between apatite  and  feldspar.   Opaque.
Brittle. Sp. gr. 6.4  to 6.6. Its  constituents
are, oxide  of uranium 86.5, black oxide of
iron 2.5, galena 6.0, silica 5.—Klaproth. It
occurs in  primitive rocks.  It is found in.
Cornwall.
   3.  Uranite, or  uran mica.
   Pyramidal  uran  mint.  Colour   grass-
green.   In flakes and  crystallized.   Triiui-
tive form, a pyramid in which the anglesare
95 ' 13' and 144" 5i/.  'The secondary form*
are, a  rectangular fbur-sided table or short
prism,  and a four-sided table variously be-
velled and  truncated.  Shining.   Cleavage
fourfold and rectangular.  T ranspaient.and
translucent.  Scratches  gypsum, but  not
calcareous spar.  Streak green. Sectile.  Not
flexible.  Easily frangible.  Sp, gr.  3.1 to
3.2.  It decrepitates  violently before tie
blow-pipe  on charcoal; loses  about 33 per
cent by ignition, and acquires a brass-yellow
colour.  Its constituents are,  oxide  of  ura-
nium, with a trace of oxide of lead 74.4, ox-
ide  of copper 8.2, w.iter  15.4.— Gregor.  I*
occurs in  veins  in primitive  rocks.  It t*
fiund in Cornwall and  Saxony. 
ORE                                   ORE
  XKIV.—Woranium Ores.
   IVoodan pyritex.   Colour dark tin-white.
In vesicular massive portions.  Lustre shin-
ingand metallic.  Fracture uneven. Opaque.
Harder than fluor, but softer  than apatite.
Brittle.   Sp.  gr. 5.192.  It contains 20 per
cent of wodanium, combined with sulphur,
arsenic, iron, and nickel.   It is said to occur
at Topschatt in Hungary.
   XXV—Zinc Ores.
   1. Red zinc, or red oxide of zinc.  Colour
blood-red.   Massive, disseminated.  On the
fresh fracture,  shining.  ^Cleavage single.
Fracture conchoidal.  Translucent on the
edges. Easily scratched by the knife.  Brit-
tle.   Streak  brownish-yeliow. Sp.gr. 6.22.
It is soluble in the mineral acids.  Its con-
stituents are, zinc 76, oxygen 16, oxides*of
manganese and iron 8__Bruoe.  It has been
Found in  New .Jersey, North America.
   2.  Zinc blende.
   Dodecahedral zinc blende.
   a.  Yellow.  Wax-yellow, and several other
colours,  inclining to green.   Massive, dis-
seminated,.and  crystallized in octahedrons,
rhomboidal dodecahedrons, and twin crys-
tals.  Splendent and adamantine. Cleavage
dodecaliedral, or sixfold. Translucent. Re-
fracts single.  Streak yellowish-gray.  Har-
der than calcareous spar.   Brittle.  Sp. gr.
4. to 4.2.   It  becomes  phosphorescent by
friction.  Its constituents  are, zinc 64, sul-
phur 20, iron 5,  fluoric acid 4, silica 1,  water
6. —Bergmann.  It occurs  in  veins, associ-
ated with  galena.   It is   found at Clifton
mine, near Tyndrum, in Perthshire, also in
Flintshire.   Fine specimens are found  in
Bohemia.
   b. Brown zinc blende.
   § 1.  Foliated.   Colour reddish-brown.
Massive, disseminated, and crystallized, in a
rhomboidal dodecahedron, an octohedron, a
tetrahedron, and acicular crystals.   Lustre
between pearly and adamantine. Cleavage
sixfold or tessular.  Translucent.   Streak
yellowish-brown.   Sp. gr. 4.048.  Its con-
stituents are, zinc  58.8, sulphur 23.5, iron
8.4, silica 7.0.—Dr. Thomson.  It occurs in
veins and beds, in primitive and transition
rocks.  It is  found in the  Clifton lead mine,
near Tyndrum; at Cumberheadin Lanark-
shire ; at  Leadhills;  and in all the lead
mines in England and Wales.
   § 2. Fibrous.  Colour dark reddish-brown.
Massive, reniform, and in  radiated concre-
tions.  Glistening, inclining to pearly.  O-
paque.  Its constituents are, zinc 62,  iron 3,
lead 5, arsenic 1, sulphur 21, alumina 2, wa-
ter 4. It occurs in Huel-Unity copper mine
in Cornwall.
   c.  Black  zinc blende.   Colour between
 grayish and  velvet-black.  Massive, dissemi-
 nated, and crystallized in the same figures
as  brown blende.  Shining,  adamantine.
 Opaque.  The  blood-red variety is translu-
cent on the edges and angles.  Streak dark
    Vol.  II.
yellowish-brown.  Sp. gr. 4.1665.  Its con-
slituentsare oxide of zinc 53, iron 12, arsen-
ic 5, sulphur 26,  water 4.  The black
blende from Naygag, besides zinc, iron, and
manganese, contains a portion of auriferous
silver.  It occurs in veins in gneiss, in Swe-
den, Saxony, &c.

Of the  Analysis  and Reduction of Ores.
   By consulting the table of metallic preci-
pitants, and studying the peculiar habitudes
ofthe individual metals and earths, the reader
may acquire a knowledge-of the methods of
separating them from one another, and de-
termining  the proportion of each.  The li-
mits of the present work permit me to offer
merely a short account ofthe best modes of
analyzing a few of the principal ores on the
small scale,  and  of  reducing them on the
large.
   1. AfTIMOM.
   1. A'ative antimony was skilfully examin-
ed by Klaproth, the father of accurate ana-
lysis, as follows- On  100 grains  ofthe pul-
verized mineral,  he  poured strong  nitric
 acid, which attacked it with vehemence,
converting it into an oxide; which being
precipitable by water,  he diluted the solu-
tion with this liquid, and then filtered. The
clear liquid was treated with muriatic acid,
 which  threw down the silver  present, in
the  state of muriate, equivalent to 1 grain of
 the  precious metal.  Prussiate of potash
 then indicated & of a grain of  iron.  The
 oxide of antimony was now dissolved in mu-
 riatic acid, the solution diluted with water,
 and a piece of zinc being introduced, pre-
 cipitated  98  grains  of metallic  antimo-
 ny.   Hence the  100 grains of native  an-
 timony from  Andreasberg, consisted of
     metallic antimony,     -      98
     silver,      ...       i
     iron,        -     -    -       0.25

                                  99.25
   Dr.  Thomson  has committed a curious
 mistake in describing this analysis.  He says,
 " When the acid  emitted  no longer  any
 nitrous gas,  the mixture  was diluted with
 water, and thrown upon a filter.  The solu-
 tion was then treated with  nitrate of silver.
 The precipitate yielded  by reduction,  1
 grain of silver."—System, 5th edition, iii p.
 608.  How 1 grain of silver was  obtained by
 treating the solution with nitrate of silver,
 it is not for me to divine.
   2. Fibrous  red antimonial ore. Klaproth
 digested 100 grains with muriatic acid, mix-
 ed  with a few drops of nitrous, in a long-
 necked matrass. There was a gray residuum
 of 1$  grains of sulphur,  " The antimony
 contained in the solution was precipitated in
 the state of a white oxide, by diluting it with
 water, and the small portion of the metal
 still remaining in that fluid, was afterwards
 entirely thrown down by means of potash.
 The oxide thus procured was redissolved irj
                   28 
ORE                                  ORE
muriatic acid, the solution diluted  with six
times its quantity of water, and once more
combined with such aproport\on ofthe same
solvent, as was necessary in order to redis-
solve entirely that portion ofthe oxide which
the affused water had precipitated  After
the dilute solution had. in this manner,again
been rendered clear, its ingredient antimony
was reproduced as metallic antimony, by im-
mersing  polished  iron  in  the  liquor.   It
weighed,  when collected, edulcorated, and
dried,  67^ grains."—Klaproth's Analytical
Essays, vol. ii. p..143. English Translation.
From the above result, and Thenard's state-
ment of the constitution ofthe oxide, Klap-
roth inferred, that the mineral consisted of,
        Metallic antimony, 67 5
        Oxvgen,     -   '   10.8
        Sulphur,     -      19.7

                           98 0
  It is painful to be obliged again to point
out a very absurd error in Dr. 'Thomson's
account of this  analysis.  He says, " The
solution was diluted with water. The whole
precipitated in the state  ofa white powder;
for potash threw nothing from the liquid."
It is hard to say whether the matter or ex-
pression be here more remarkable:  Potash
did throw something from the liquid;  and
must do so, because oxide of antimony is so-
luble in an excess of muriatic acid; on which
fact, indeed, this and the preceding analysis
are founded
  3. "Sulphuret of antimony is to be treated
with nitro muriatic acid.  The sulphur and
the muriate of silver (if any  silver be pre-
sent) will remain   Water precipitates the
antimony; sulphuric acid the lead ; and am-
monia the  iron."—Thomson's  System,  5th
edition, iii. 609.  This paragraph betrays a
strange forge tfulness ofthe first principles of
chemistry; for, in the first place, nitro-
muriatic acid will acidify a portion of the
sulphur, and therefore the sidphur will not
remain; in the second place, a  portion  of
oxide of antimony will continue combined
with the excess of muriatic acid; and, in the
third place, the acidified sulphur will throw
down, at first, the lead in the state of insolu-
ble sulphate, along with the muriate of sil-
ver.
   If tl.e pulverized sulphuret of antimony
be acted on  by nitric  acid, with heat,  and
water be afterwards added, a precipitate will
fall, consisting of oxide of antimony, with
sulphur and sulphate of lead.  Sulphate  of
silver being very soluble in dilute nitric acid,
will remain in the liquid.   Muriate of soda
\* ill throw down the  silver, without affect-
ing the lead, if the solution be hot and some-
what dilute.   The lead, if any remain, may
then be precipitated by sulphate of soda in
equivalent quantity, or by hydrosulphuret of
amm'iiia ;'by muriate of barytes, the  sul-
phuric acid  resulting from acidification  of
the sulphur may be ascertained; and by fer-
roprussiate of potash, the iron.  On the first
precipitate obtained by affusion of water, if
muriatic acid be digested, the oxide of a,nti-
moii) will be taken up, and may be recover-
ed in the  metallic  state, by immersing a
piece of zinc or iron in the muriatic solution.
Lastly, the sulphur may he separated from
the sulphate of lead by ustulation.
  Metallic antimony  is best obtained from
the sulphuret, by igniting it, after careful
ustulation,  with  half its  weight of crude
tartar.  The metal will be found at the hot-
torn ofthe crucible. Or the ustulatcd oxide,
mixed with oil, fax, and pounded charcoal, is
to be ignited till drops ofthe metal begin to
appear; and nitre  equal to  l-16th  of the
weight ofthe oxide is then to be gradually
injected.  Or we form the martial rcgulusof
antimony (antimony  containing a little iron
and  sulphur), hy adding 16 ounces  of the
sulphuret to six ounces of iron nails, ignited
to whiteness in a crucible. When the whole
are in fusion, inject gradually two ounces of
pulverized nitre; then cover the crucible,
and urge the heat for a little.  Seven or
eight ounces ofthe re gulus will be found at
the bottom.  By repeating the fusion, ar>d
projection of nitre, two or three times, the
regulus may be brought nearer to the state
of pure metal.
  In what follows, I shall confine myself to
the detail of a few ingenious and exact ana-
lyses.
  2.  Bismuth Ores.
  The following analysis of  a complex me-
tallic mineral by Klaproth is  peculiarly in-
structive.
  Examination in the humid  way  of the
bismuthic silver  ore from Schaupbach,  in
the Black Forest, in Suabia.
  (a.) Upon 300 grains of this ore, he pour-
ed three ounces of nitric acid, diluted with
one ounce of water.   The residuum being
acted on with more acid, buth solutions were
mixed,  and evaporated to a small volume ;
during which process, there separated from
the fluid some crystalline grains,  consisting
of nitrate of lead.
  (b.) The concentrate rl solution had a green-
ish colour.  When afterwards diluted with
just as much water  as  was requisite to  rc-
dissolve  that crystalline sediment,  it was
poured into a large quantity of water  This
iast immediately acquired a  milky appear-
ance, in a  high  degree, and  deposited  a
white precipitate, which weighed 44} grains,
when collected, lixiviated, and dried in the
air, and proved, on further examination, to
be oxide of bismuth.
  (c.) Into the liquor, that bad been freed
from this oxide,  and was entirely clear and
colourless, he then dropped muriatic acid as
long as it was rendered turbid  by it. The
precipitate, which now fell, did not appear
to be mere muriate of silver; for this reason
he digested it for some time  with a  mode-
rately strong nitric acid.  A considerable 
ORE
ORE
portion of it was thus  redissolved,  and left
pure horn-silver behind; which, upon careful
collection, and desiccation in a brisk heat,
weighed 46 grains.   Thus, the portion of
pure silver is determined at 34$ grains.
  (d.) The nitric acid that had been affused
upon  the precipitate  obtained by  the mu-
riatic  (c), yielded by dilution with much wa-
ter, 32 grains  more  of oxidized bismuth ;
which, with the preceding 44$ (6), gave to-
gether 76$ grains.  In order to ascertain the
proportion of  reguline bismuth in this ore,
he dissolved 100 grains of bismuth in nitric
acid;  and after having concentrated the so-
lution by evaporation, he poured it  into a
large  quantity oftwater.  When, ofthe pre-
cipitate thus produced, nothing more would
fall down, on adding more water he collect-
ed it, on the filter, washed it, and suffered
it to dry perfectly in the air.  It then weigh-
ed 88 grains. To the water which had been
separated from it, muriatic acid was added
by drops ; whereby a  new precipitate ensu-
ed, weighing  32 grains, after edulcoration
and drying.
  As, by the result of this comparative ex-
periment, 100 grains of bismuth have} upon
the whole, given 123  grains of oxide, it fol-
lows that the 76$ grains of oxide  (d), ob-
tained from 300 grains of  this ore, contain
62-J- grains of metallic bismuth.
  (e)  The remainder of the  fluid  was fur-
ther reduced  by  evaporation ; and  in this
process, muriate of lead separated from it in
delicate broad striated crystals.  This liquor
was then combined with such a quantity of
sulphuric acid, as was requisite to redissolve
those crystals, and a second time evaporated
to a consistence of pap.   The precipitate
which thence  ensued, was sulphate of lead,
weighing  19 grains, when duly collected,
washed and dried.
  If.) What still remained of the  solution,
after its having been freed from the lead be-
fore contained in it, was saturated with caus-
tic ammonia added in excess.  In this way,
a brown ferruginous precipitate was pro-
duced; which was rapidly attracted by the
magnet, and weighed 14 grains, when, after
previous desiccation, it had been moistened
with linseed oil, and well ignited. For these
we must reckon 10 grains of metallic iron,
  (g.) 'The  liquor which  had been  super-
saturated with ammonia, and which, by its
blue colour, shewed that it held copper in
solution, was saturated to excess with sul-
phuric acid.  On immersing then a piece of
polished iron into it,  two grains of copper
were  deposited.
  (h.) The gray residue ofthe ore, that was
left behind by the nitric acid (a), weighed
178 grains.  But when its sulphureous part
had been deflagrated, in a crucible gently
heated, it weighed only 140$  grains.  This
determines the portion of sulphur at 37%
grains.
  (»".) These 140$ grains were digested with
three ounces of muriatic acid, in a heat of
ebullition ; and the process was repeated
once more  with 1$ ounce ofthe same acid.
These solutions, by means of  evaporation,
yielded till the end, muriate of lead in tender
spicular, and likewise in broad striated crys-
tals; which, when again dissolved in the re-
quisite quantity of boiling water, then com-
bined with sulphuric acid, and evaporated,
yielded 89 grains of sulphate of lead.  Thus,
the whole quantity of this sulphate, includ-
ing the 19 grains mentioned at  (e), amount-
ed to 108  grains; for which, according to
comparative experiments, 76 grains of regu-
line lead must be put in  the computation.
  (k.) That portion of  the ore examined,
which still remained after all the constituent
parts before mentioned had been discovered,
consisted merely of the gray quartzose ma-
trix ,- the  Weight of which, in the ignited
state, amounted to 70 grains.
  'Therefore, these 300 grains  of bismuthic
silver ore were decomposed into
                             Exc. of mat.
  Lead,     (i)           76.00    33.00
  Bismuth,  (d)          62.20    27.00
  Silver,    (c)           34.50    15.00
  Iron,    (/)         10.00    4.30
  Copper, (g)           2.00    0.90
  Sulphur, (h)          37.50    16.30
  Quartzose matrix, (k)  70.00

                       292.20    96.5
  3. Analysis of Ckhitf. by Vauquelin:—
  'The specimen was ofa slight  rose colour ;
and sufficiently  hard to scratch glass.   Sp.
gr  4.53.  Streak grayish. It reddened with
calcination, losing 12 per cent.
  (a.) 100 grains of this mineral, in fine
powder, were mixed with ten times their
weight of nitro-muriatic acid, and subjected
to ebullition for an hour; the mixture being
diluted with water, and filtered, left on the
filter a brown dust, which  was dried and
fused  with  caustic potash.  The  mixture
being diluted with water, and then dissolved
in muriatic acid, evaporated to  dryness, and
redissolved in water, left a powder which,
when collected on  a filter, washed  and cal-
cined, weighed 17 parts ; it was pure silex,
still slightly coloured yellow.
  (b.)  The nitro-muriatic  solution being
evaporated  to dryness,  and its  residuum
redissolved in water, left about one part of
silex, coloured by a little oxide of cerium.
  (c )  The same solution, freed from silex,
and united to the washings ofthe silex, was
decomposed by ammonia; the oxide of ce-
rium and the oxide of iron, precipitated by
this means, were separated from the liquid
by filtration.  'The oxalic acid added to this
liquid, formed a precipitate,  which, by cal-
cination, gave two parts of lime.
  (d.) The  metallic oxides united and cal-
cined, weighed 70  parts; they had a beau-
tiful reddish-brown colour. To separate the
iron from the cerium, the whole was dis* 
ORE
ORE
 solved in muriatic acid; the solution being
 coiicenv ared to  evaporate  the excess of
 acid, then  diluted with water, and decom-
 posed by tartrate of potash, there was form-
 ed a very abundant white precipitate, which
 being  washed till  it contained no more
 foreign salts, then dried and calcined, gave
 67 parts of oxide of cerium.
   (e.) The water froth the washing ofthe
 tartrate of  cerium, being united and mixed
 with hydrosulphuret of potash, gave a pre-
 cipitate which became black in the air.  It
 was oxide  of iron, the weight of which, af-
 ter calcination, was two parts.
   Thus, 100 parts  of cerite furnished by
 this analysis,
   Silica, (a) (6)........17
   Lime, (c).........2
   Oxide of iron, (d)......2
   Oxide of cerium, (e).....67
   Water and carbonic acid, by estimate,  12
                                    100
   4. Copper  Ores.   Analysis of Siberian
 malachite, by Klaproth:—
   (a.) 100 grains of malachite reduced to
 powder by  trituration, were dissolved in ni-
 tric acid; which was effected without leav-
 ing any residue.  The solution had a bright
 blue colour; and was saturated to excess
 with  ammonia;  but the precipitate pro-
 duced was  entirely  and without tardiness
 redissolved  by  the   excess of the  alkali.
 This shewed that the malachite here  ex-
 amined was perfectly  free from  iron, and
 similar admixtures.
   (b ) He combined  100 grains of triturated
 malachite, with a sufficient quantity of sul-
 phuric  acid, previously diluted  with five
 parts of waier, and accurately weighed to-
 gether  with the vessel.  After the mala-
 chite  had been  wholly dissolved,  which
 was effected gradually, and  with a moder-
 ately strong effervescence, the loss of weight
 occasioned  by  the carbonic, acid gas, that
 was extricated, was found to consist of 18 gr.
   (c.) 100 grains of the same powdered ma-
lachite,  were ignited at a moderate heat in
a covered crucible.  The black residue had
lost 29$ grains in weight.  If from these be
 subtracted 18 grains  for the carbonic acid,
 the remaining 11$ grains of loss will con-
 sist of water.
   (d.) And  lastly, 100 grains, which had
been dissolved in dilute sulphuric acid, and
precipitated by zinc,  yielded  58 grains of
pure copper.
  In consequence of these experiments,
the Siberian malachite consists of
            Copper,        58
            Carbonic acid, 18
            Oxygen,       12.5
            Mater,         11.5

                         100.0
  5. Gold Ores.  A very instructive analy-
sis ofthe Transylvanian auriferous lamellar
ore, from Naygag, by Klaproth :—
   (a.) 1000 grains, freed in the best possf.
 ble manner from  the stony matrix, v « re
 triturated, and digested at a moderate heat,
 first with ten ounces of muriatic mid,to
 which nitric acid was  gradually  added.  A
 violent action then  took  place, and the
 black colour of the powdered ore rapidly
 disappeared.  While the  fluid was yet hot,
 it was poured upon a filter; and the residue
 was once more digested with five ounces of
 muriatic acid,  and the whole filtered. In a
 short time acicular crystals were  deposited
 in the solution, which  was yellow, and like-
 wise on the filtering paper.  These crystals
 were  covered with boiling hot  water, till
 they were all dissolved i after which only
 the quartzose portion of the matrix and
 some sulphur lemained.
   (b.)  The  sulphurous  ingredient  in the
 ore, had  united into  a coherent mass, and
 could therefore be easily removed from the
 earthy residue. Its weight was 17$ grains.
 Burned on a moderately heated calcining
 test, it  left 3$  grains of blackish residuum,
 which  was dissolved in  muriatic  acid and
 added to the foregoing solution. Hence the
 quantity of sulphur was 14 grains.
   (c.)  That  portion  of  the matrix which
 consisted of white grains of quartz, weighed
 in the  dry state 440$  grains. This  being
 mixed  with  four  times its  quantity of car-
 bonate of potash, was melted to vitrifaction.
 On breaking the crucible, a few globules of
 silver were found  dispersed; which, how-
 ever, could not be well collected.  But from
 another experiment, to be mentioned in the
 sequel, it resulted, that this silver may be es-
 timated at 2$ grains.  \\ hence, since m the
 present case, it was in the state of muriate,
 3$ grains are to be subtracted, so that ofthe
 above stated weight 437 grains remain.
  (d.)  The solution (a), from which.fon ad-
 dition ofthe edulcorating ua'er, a white tel-
 luric oxide fell down  in  a  great quantity,
 was concentrated  by  evaporation; during
 which  process that precipitate again en-
 tirely dissolved. On the other hand, nume-
 rous crystals of muriate of lead  were de-
 posited from the liquor, even  while warm ;
 which being taken out, the evaporation was
 carried on as long  as any more of them ap-
 peared.  These crystals,  when collected,
 were carefully rinsed, by  dropping  upon
 them muriatic acid, and highly dried. They
 weighed 330 grains, equiv alentto 248 grains
 of lead in the metallic state.
  (e.) After the concentrated solution had
 been thus freed from   lead,  he diluted it a
 little with water, and added a large quanti-
 tv of spirit of  wine, as long as any white
 precipitate fell.  The mixture having stood
 for a while in a gentle warmth, that precipi-
 tate  was collected on the filter, edulco-
 rated with ardent spirit, redissolved in mu-
riatic acid, and precipitated again in the state
 ofa pure telluric oxide, by means of caustic
soda, and by strictly watching the precise 
ORE                                  ORE
  point of saturation. This oxide, washed and
  dried, gave in the balance 178 grains, which
  correspond to 148 grains of reguline tellu-
  rium.
    (/.) For the purpose of ascertaining the
  proportion of gold, he now reduced the flu-
  id, from which the tellurium had been se-
  parated, by distilling off the spirit of wine
  in a retort; diluted again the concentrated
  solution with water; and lastly,  dropped
  into it a nitric solution of mercury, prepared
  without the assistance of heat; adding this
  nitrate, until no brown  precipitate any lon-
  ger appeared, and till the white precipitate
  which  succeeded the  brown,  no  more
  changed its own colour. After this the mix-
  ture was  placed in   a warm temperature,
  where  the  white precipitate, which was
  owing to the nitrated mercury added in ex-
  cess, again  gradually  disappeared.   The
  brown precipitate, which fell to the bottom
  as a heavy powder, was the gold sought for.
  When collected and  fused  with nitrate of
  potash, it gave a bead of pure gold, weigh-
  ing 41$ grains.
    (g.) The liquor was now saturated with
  carbonate of soda, in a boiling heat.   A co-.
  pious bluish-gray precipitate ensued, which
  turned black-brown by ignition.  Digested
  with muriatic acid, it  dissolved again  clear-
  ly, and gave out oxygenated muriatic acid
  gas. By combining this solution with liquid
  carbonate of ammonia to a considerable de-
  gree  of supersaturation, a  grayish-white
 'precipitate was produced; which, collected,
  washed, and dried, weighed 92 grains, and
  proved  to be a somewhat iron shot, carbo-
  nated oxide ofmanganese.
    (h.) The  ammoniacal lixivium (g) ap-
 peared ofa blue colour.  After being super-
 saturated with sulphuric acid, by which it
 was again rendered colourless, a small plate
 of polished  iron  was introduced,  and the
 vessel put in a warm  place.  The iron be-
 came  gradually coated with copper, the
 weight of which after drying was six grains.
   Therefore the 1000  grains Exclusive ofthe
 were decomposed into      matrix of quartz
                            and  mangnesi-
                            an ore,
 Lead, (d)
 Tellurium, (e)
 Odd, (/)
 Silver, (c)
 Copper(h)
 Sulphur, (b)
 Oxide ofmanganese, (g)
 Quartz, (c)

              Loss,
                      1000.0
  6. Iro* Ores are usually analyzed by fu-
sion. On this  subject, there is a valuable es-
say bv  Mr.  Mushet, in the 4th volume of
the Phil. Magazine.  In the hematites iron
ore, for 1 pound avoirdupois, he commonly
added 6  ounces dried  chalk, and | of an
248.0	54.0
148.0	32.2
41.5	9.0
2.5	0.5
6.0	1.3
14.0	3.0
) 92.0	---
437.0	100.0
""989.0	
11.0	
  ounce of charcoal; and for the splinty blue
  ore also a similar mixture.  From both of
  these mixtures, he obtained the richest sort
  of crude iron. The kidney ore will admit of
  a diminution of chalk, and a small addition
  of glass.  One pound avoirdupois of this va-
  riety will be accurately assayed by the ad-
  dition of 5 ounces chalk, I ounce glass, and
  | of an ounce of charcoal.  The same pro-
  portion of mixtures will also accurately re-
  duce the small pieces of this ore, commonly
  of a  soft  greasy  consistence, mixed with
  small fragments of the hematites and the
  kidney, and  will give out the iron which
  they contain, supercarburctted. A mixture
  of this soft ore, with kidney, is preferred to
  the richer variety, at the iron manufactories.
  The Lancashire ore consists chiefly of this
  compound, and the poorer in iron has al-
  ways a decided preference given it, at the
  blast-furnace. The Elba ore may be reduced
  into smooth  carburetted iron, by exposing
  to a melting heat 2 ounces of it mixed with
  2 ounces of chalk, 1$ ounce bottle-glass,
  and I ounce  of charcoal. To  the Islay iron
  ore, and the  Norwegian, Danish, and Swe-
  dish, Mr. Mushet adds, for every  pound, 7
  ounces of dried chalk, 3 of bottle-glass, and
  1 of charcoal. By carburetted iron is meant
  cast-iron.
    I shall now give an outline of Mr. Hat-
  chett's much admired analysis of the mag-
  netical pyrites.
   (a.) 100 grains reduced to a .fine powder,
  were digested with two ounces of muriatic
  acid, in a glass matrass placed in a sand-bath.
 A strong effervescence ensued, occasioned
 by the production of sulphuretted hydrogen
 gas; and  a pale yellowish-green  solution
 was formed.  The residuum was then again
 digested with two parts of muriatic acid,
 mixed with one of nitric acid;  and a quan-
 tity of  pure sulphur was obtained, which,
 being dried, weighed 14 grains.
   (b.) The acid in which the residuum had
 been digested, was added to the first muri-
 atic solution; some nitric acid was also pour-*
 ed in to promote  the  oxidizement of the
 iron, and thereby to facilitate the precipita-
 tion of it by ammonia, which was added after
 the liquor had been boiled for a considera-
 ble  time.  The precipitate thus obtained
 was boiled with lixivium of potash; it was
 then edulcorated, dried, made red-hot with
 wax in  a covered porcelain crucible, and
 completely taken up by a magnet, and being
 weighed, amounted to 80 grains.
   (c.) The lixivium of potash was examined
 by muriate of ammonia, but no  alumina was
 obtained.
  (d.) To the filtered liquor, from which the
 iron had been  precipitated by ammonia, mu-
 riate of barytes was added, until it ceased to
 produce any precipitate;  this was then di-
 gested with some very dilute muriatic acid;
 was collected, washed, and after exposure
to a low red heat, for a few minutes in a cru- 
ORE                                   ORE
cible of platinum, weighed 155 grains.  If
therefore *he quantity of sulphur converted
into sulphuric acid by the preceding opera-
tions, and precipitated by barytes, be calcu-
lated  according to the experiments of M.
Chenevix, then, 155  grains of sulphate of
barytes. will denote nearly 22.5 of sulphur,
(2f. Dr. Wollaston's scale); so that with the
addition ofthe 14 grains previously obtained
in substance, the total quantity will amount
to 36.5, (35).
  (e.) Moreover, from what has been stated,
it appears, that the iron which was obtained
in the form of black oxide, weighed  80
grains; and by adding these 80 grains to
the 36.5 of sulphur, an increase of weight is
found = 16.5.   This was evidently owing
to the oxidizement ofthe iron, which in the
magnetical pyrites, exists quite or very nearly
in tiie metallic state ; but by the operations
of the analysis, has received this addition.
The real quantity of iron must on this ac-
count be  estimated at 63.5.  100 grains
therefore, ofthe magnetical pyrites yielded,
  S„H.I.ur,  [W  g* {]{]\ «UT (35)
  Iron,      (e)          = 63.5 (62.22)

                            100.0  97.22
  This analysis was repeated  in a similar
manner, exceptingthat the whole v\ as diges-
ted in nitric acid,  until the sulphur was en-
tirely converted into sulphuric acid. 'To the
liquor which remained after the separation of
the iron by ammonia, muriate of barytes was
added, as before, and formed a precipitate
which weighed 245 grains.  Now these, by
Dr. Wollaston's  scale, are  equivalent  to
nearly 33.5 of sulphur.  Hence  it would ap-
pear,  that a little sulphur is dissipated, in
the form of sulphurous acid, by this  mode
of operation.
  The theoretical equivalent proportions
of magnetic pyrites are,
       Sulphur,    36.363      2.00
       Iron,       63.636      3.50
* We thus see, that Mr. Ilatchett's final
sta< ement is almost exact, in consequence of
M.  Chenevix's  erroneous estimate of the
composition of sulphuric acid and sulphate
of barytes, making a compensation for the
experimental deviation, or loss; amounting
 on  the iron to 1.416, and on the sulphur to
 1.363, in the 100 parts.
   Analysis of arseniate of iron, by M. Che-
nevix :—
   100 grains boiled with potash left 58.5.
 The liquor treated by nitrate of lead, gave
of arseniate of lead, a quantity which  he  es-
 timated as equivalent to 31 of arsenic acid.
 The 58.5  left 4, which muriatic acid could
 fiot dissolve, and which were silica. Ammo-
 nia dissolved 9, and there remained 45.5 of
 oxide of iron.   This analysis  presents the
 following  results:
       Arsenic acid,      -    31.00
       Oxide of iron,     -    45.50
      Oxide of copper,   -      9.00
      Silica,       .    -      4,00
      M ater, by inference,    10-50

                            100 00
  7. Lear Ore.  Analysis of \ellow lead
ore from Wanlockhead, by Klaproth  :—
  («.) Upon 100 grains of this ore  finely
levigated, dilute nitric acid was poured and
heated.  They dissolved, and only a few in-
considerable flocks escapedthe action ofthe
solvent.   The  filtered  colourless solution,
when treated with nitrate of silver, gave 10$
muriate of silver, which indicates, say s Klap-
roth, 1.62 grains dry muriatic acid.
  (b.) Sulphuric acid was then presented to
the solution.  It precipitated the lead con-
tained in that fluid in the state of sulphate ;
which having suffered a red heat, weighed
108-g- grains ; for which 80 grains of oxide
of lead must be allowed.
  (c.) 'The excess of sulphuric acid being se-
parated by means of nilrtae of barytes. am-
monia was added to the  saturation  of  the
nitric acid, and the phosphoric acid was then
thrown down with  acetate of lead.   From
•80 grains of phosphate of'lead thusohtained,
he inferred  18 grains of phosphoric  acid to
have existed in the ore.
  The residuary part ofthe fluid contained
nothing more ofthe constituent parts of the
mineral, excepting  a slight trace of iron.
Consequently 100 gr. were  resolved into—
         Oxide of lead,    80.
         Phosphoric acid, 18.
         Muriatic acid,      1.62
                        99.62
  8.  Analysis  of Ghat  Silver  Ore, by
Klaproth :—
  (a.)  300 grains ofthe fragments selected
from the pounded ore, though not perfectly
separable from the quartzose gangue, with
which they were firmly concreted, were le-
vigated to a subtle powder, and digested
with four times their weight of nitric acid.
The digestion was renewed with the resi-
duum, in an equal quantity ofthe same acid;
and the portion which still remained undis-
solved then assumed a grayish-yellow co-
lour, and weighed 188 grains.
  (bT)  By the  addition of muriate of soda to
the  bright green nitric  solution, its silver
was thrown down ; and this  precipitate col-
lected and reduced by means of soda, yield-
ed 31$ grains of metallic silver.
  (c.)  The silver being thus separated, lie
tried the solution for lead ;  but neither the
neutral sulphates, nor free  sulphuric acid,
could discover the least sign of it.
  (d.) After this he added  caustic volatile
alkali, so as to .supersaturate the acid; upon
which a reddish-brown precipitate, ofa loose
cohesion, appeared, that by  ignition became
ofa black-brown, and. weighed 9£  grains.
It dissolved in nitric acid, leaving behind it
half a  grain of siliceous earth.  Prussiate of 
ORE                                  ORE
potash produced from the filtered solution a
deep blue precipitate of iron; and after this
wasseparated, 1$ grains of alumina were ob-
tained from it by means of soda. 'Therefore
subtracting the siliceous and argillaceous
earths, the portion of iron attractible by the
magnet amounted to 7\ grains.
  (e.) To the solution, which had been be-
fore supersaturated with pure ammonia, and
exhibited a sapphire-blue colour, sulphuric
acid was now added to excess.  A polished
piece of iron was then immersed into the
fluid, from which it precipitated 69 grains
of copper.
  (/.) The  above grayish-yellow residuum
(a) was now to be examined.  It was di-
gested with six times its quantity of muriatic
acid, in a heat of ebullition. When filtered,'
the residue which was left on the paper, be-
ing first washed  with muriatic acid, then
with a  little alcohol, and lastly dried, was
'found to weigh 105$ grains.
   (g.) From the solution which was obtain-
 ed by the last process, and was of a straw-
yellow, the greater part of the fluid  was
drawn off by a  gentle distillation in a retort.
The remaining concentrated solution then
deposited some  crystalline  grains,  which
were carefully collected, and proved upon
inquiry to be muriate of silver, weighing £
ofa grain. A large quantity of « ater being
next poured into the solution, a copious pre-
dpitete subsided, weighing after desiccation
 97i grains.   It proved by every test to be
oxide of antimony, for which, as was found
by comparative experiments, 75 grains of
reguline antimony must be allowed.
   (A.) The residue obtained (f) weighing
 1*05$ grains, which comprised the sulphure-
ous part of the ore, was exposed to a low
heat, by which treatment the sulphur was
consumed,  and 80i  grains of silica remain-
 ed.   Hence the quantity ofthe sulphur was
 equal to 25$ grains.
   (*'.) The  siliceous  earth was next fused
 with four times its weight of black flux.  The
 melted mass entirely dissolved in twice its
 weight of water into liquor of flints ; some
 minute particles of silver, weighing three-
 fourths ofa grain, excepted.  According to
 this, the proportion  of silica amounted to
 79$ grains.

   The whole constituents therefore are,—
			Ore	, exclusive
Silver,	(*)	31.5 ~)	of silica, in 100.	
	(ft)	0.25 C	. 32.50	14.77
	(0	0.75)		
Copper,	(<0		69.00	31.36
Antimony	.(*)		75.00	34.09
Iron,	(d)		7.25	3.30
Sulphur,	(h)		25.25	11.50
Alumina,	(■rf)		1.50	0.30
Silica,      (d) and (i) 80.00    95.32
  9. Analysis of Tin Ores by Klaproth :—
  1. Tinstone.
  (a.) 100 grains of tinstone from Alter-
non,  in  Cornwall, previously ground to a
subtle powder, were mixed in a silver ves-
sel, with a lixivium containing 600 grains of
caustic potash.   'This mixture was evapora-
ted to dry ness in a sand heat, and then mo-
derately ignited for half an hour. When the
gray-white mass, thus  obtained,  had been
softened while yet warm  with boiling wa-
ter, it left on the filter 11 grains of an un-
dissolved residue.
   (b.) These 11 grains, again Ignited with
6 times their weight of caustic potash, and
dissolved in boiling water, left now only li
grains of a  fine  yellowish-gray powder be-
hind.
   (c.)  The  alkaline solution, (a  and b),
which was in some degree, colourless, was
saturated with muriatic acid.  A  brilliant
white tender oxide of tin was thrown down
giving to the mixture  a milky appearance.
This precipitate, redissolved by an addition-
al quantity  of muriatic acid, was precipita-
ted afresh by means of carbonate of soda.
When lixiviated and dried in a gentle heat,
it acquired the form of bright yellowish
transparent lumps, having in their fracture a
vitreous lustre.
   (d.) This precipitate being finely powder-
ed, soon dissolved entirely in muriatic acid,
assisted by a gentle heat.  Into the colour-
less solution, previously diluted with from 2
to 3 parts of water, he put a stick of zinc ;
and the oxide of tin, thus reduced, gathered
around it, in delicate dendritic laminae, of a
 metallic lustre.   These, when collected,
washed, dried,  and fused under a cover  of
 tallow, in a capsule placed upon charcoal,
 yielded a button of pure metallic tin, weigh-
 ing 77  grains.
   (e.) The above mentioned residue of li
 grains, left by  the treatment with caustic
 potash  (4), afforded with muriatic acid a yel-
 lowish  solution ; from  which, by means ofa
 little piece of zinc introduced into it, $ grain
 of tin was still deposited.  Ferropiussiate  of
 potash, added to the remainder ofthe solu-
 tion, produced a small portion ofa light blue
 precipitate ; of which, after deducting the
 oxide of tin, now combined with it, hardly £
 of a grain remained, to be  put to the account
 of the  iron, contained in  the tinstone, here
 examined.
   In these  experiments,  (excepting only a
 slight indication of silex, amounting to about
 £ of a grain), no trace appeared, either  of
 tungstic oxide, which some mineralogists
 have supposed to be one  ofthe constituent
 parts of tinstone, nor of any other fixed sub-
 stance. "*'!'.■ ■e~,re what is deficient in the
 sum, to m;". • up the original weight ofthe
 mineral analyzed, must be ascribed to the
 loss of oxygen; and thus the constituent parts
 of pure tinstone from Alternon, are to each
 other in the following proportion 
ORE                                 ore
             Tin,      77.50
             Iron,       0.25
             Silica,      0.75
             Oxygen,   21.50

                      100.00
   2.  Tin pyrites, from Wheal-Rock, St.
Agnes in Cornwall.
   (a.)  120 grains of finely triturated tin
pyrites were treated with an aqua regia, com-
posed of 1 ounce muriatic acid, and $ ounce
of nitric acid. Within 24 hours, the greatest
part of the metallic portion was dissolved in
it, without application  of heat; while the
sulphur rose up and floated on the surface of
the menstruum. Afterthe mixture hadbeen
digested upon it for some time in a low sand
heat, it was diluted with water, and thrown
on a filter.  It left 43 grains of sulphur on
the paper, still, however, mixed with metallic
particles.  When the sulphur had been gen-
tly burnt off on a test, there still remained
13 grains ; of which 8 were dissolved by ni-
tro-muriatic acid.   The remaining part was
then ignited with a little wax;  upon which
the magnet attracted 1 grain of it.   What
remained was part of the siliceous matrix,
and weighed 3 grains.
  (b). The solution ofthe metallic portion
(a) was combined with carbonate of potash;
and the dirty-green precipitate, thus obtain-
ed, was redissolved in muriatic acid, diluted
with 3 parts of water.  Into this fluid, a cy-
linder of pure metallic tin,  weighing 217
grains, was immersed.  The result was, that
the portion of copper contained in the solu-
tion, deposited itself on the cylinder of tin;
at the same time that the fluid began to lose
its green colour, from the bottom upwards,
until after the complete precipitation ofthe
copper in the reguline state, it became quite
colourless.
  (c.) The copper thus obtained weighed
44 grains. By brisk digestion in nitric acid,
it dissolved, forming a blue tincture, and left
1 grain of tin behind, in the character of a
white oxide. Thus the portion of pure cop-
per consisted of 43 grains.
  (d.) The cylinder of tin employed to pre-
cipitate the copper, now weighed 128 grains;
so that 89  grains of it had entered into the
muriatic solution.  From this, by means of
a cylinder of zinc, he reproduced the whole
of the dissolved tin, which was loosely de-
posited n pon the zinc, in a tender dendritical
form. When the tin was all precipitated, he
collected and lixiviated carefully, and suffer-
ed it to dry.  ft  weighed 130 grains.  By
mixing  it with tallow,  he melted  it into'
grains, under a cover of charcoal dust, in a
small crucible; and separated the powder of
the coal by elutriation. Among the washed
grains of tin, some  black particles  of iron
were observed, which were attractible by the
magnet, and weighed I grain.  Deducting
this, there remain 129 grains for the weight
ofthe tin. By substrarting again from these
last those 89 grains, which proceeded from
the cylinder of tin employed for the preci-
pitation of the copper (b), there remained
40 grains, for the portion of tin contained in
the tin pyrites examined.  Hence, including
the 1 grain of tin, which had been separated
from the solution ofthe copper (r), the por-
tion of pure tin contained in this ore amoun-
ted to 41 grains.   The following is a view
In 120 gr.		In 100.
Sulphur	30	25
Tin,	41	34
Copper,	43	36
Iron,	2	2
Gangue,	3	—
	--	97
	119	
  The darker varieties  are considerably
poorer in tin.  The reduction ofthe ores of
tin is  effected, by roasting the ore after it
has been pulverized in stamping mills, ana
then exposing it to  heat, in a reverberatory
or blast furnace, along with Welch small
coal or culm. If much copper be present, it
is afterwards fused  at a very gentle heat,
and what flows off is pretty pure tin.
  Zinc is reduced by distillation of its ore
(previously roasted) in a retort, along with
charcoal.*
  A sulphuret of zinc was lately met with in
one  of the Gwennap mines, incrusting a
spongy pyrites intermixed with quartz, ami
so like wood-tin, as to be supposed a variety
of it by the miners.  According to Dr. Kidd,
it consists of 66 oxide of zinc, 33 sulphur,
and a very  minute portion of iron.  The
pyrites contains cobalt.
  In the dry way, zinc is reduced by distil-
ling its ore after torrefaction, with a mixture
of its own weight of charcoal, in an earthen
retort well luted, and a strong heat: but by
this method scarce half the zinc it contains
is obtained.
   'The first dressingofcalamine forthe large
works of zinc, consists in picking out all the
pieces of lead ore, lime, and ironstone, cauk,
and other heterogeneous substances, which
are found mixed with it in the mine : it is
then  roasted in proper furnaces, where it
loses about  a  third or fourth part of its
weight.   It is picked out again very care-
fully, as  the heterogeneous particles have
become more discernible by the action of
the fire; it is then ground to a fine powder,
and washed in a gentle rill of water, which
carries off the earthy mixtures of extraneous
matters; so that, by these processes, a ton
ofthe crude calamine of Derbyshire is re-
duced to 12 cwt. only.
   Bergmann affirms, that a certain English-
man,  whose name  he  does not  mention,
made, several years ago, a voyage to China,
for the purpose of learning the art of smelt-
ing zinc, or tutenague ; and that he became
instructed in the secret, and rciurned safe-
!v home. 
OSM                                   OXA
  It is not improbable, but that a fact of this
kind may have served to establish the nia-
nufactorv of zinc in England about the year
1743, when Mr. Champion obtained a patent
for the making of it, and built the first work
of  the kind  near  Bristol.  It consists,  as
Watson relates, of a circular kind of oven,
like a  glass-house furnace,  in  which were
placed six pots, of about four  feet each  in
height, much resembling large oil jars  in
shape ; into the bottom of each pot is insert-
ed  an iron tube, which passes through the
floor ofthe furnace, into a vessel of water.
A mixture ofthe prepared ore is made with
charcoal, and the pots are filled  v. ith it to
tho mouth,  which are then close stopped
with strong covers,  and luted with clay.
The fire  being properly applied, the metal-
lic  vapour  of the  calamine issues, down-
wards, or per descensum, through the iron
tubes,  there being no other place through
which  it  can escape ; and the air being ex-
cluded, it does not take fire, but is conden-
sed in  the water into granulated particles ;
which, being remelted, are cast into ingots,
and sent  to Birmingham under the name of
zinc, or spelter; although by this last name
of spelter,  only a granulated  kind of soft
brass is understood among the  braziers, and
others  who work in London, used to solder
pieces  of brass together.
  •Orichalccm. The brass of the ancients;
their ses was a species of bronze.*
  •Orpiment.  Sulphuret of arsenic.  See
Ores of  Arsenic*
  •Orthite. A mineral so named because
it always occurs in straight layers, generally
in feldspar. It resembles gadolinite, and con-
sists of, peroxide of cerium 19.5, protoxide
of iron 12.44, protoxide  ofmanganese o.44,
yttria  3.44,  silica 32.0, alumina 14.8, lime
7.84, water 5.36,—Berzelius.  It is found
in the  mine of Finbo, in the vicinity of Fah-
lum in Sweden.   The mine is situated in a
vein of granite which traverses gneiss.*
  * Osmazome.  If  cold water which has
been digested, for a few hours, on slices of
raw muscular fibre, with occasional pressure,
be  evaporated, filtered, and then treated
with pure alcohol, a peculiar animal princi-
ple will be dissolved, to the exclusion ofthe
salts. By dissipating the alcohol with a gen-
tle  heat,  the osmazome is obtained.   It has
a brownish-yellow colour, and the taste and
smell of soup.  Its aqueous solution affords
precipitates with infusion  of nut-galls,  ni-
trate of mercury, and nitrate and acetate of

  OsnifM.  A new metal lalely discovered
by  Mr. 'Tennant among platina,  and thus
called  bv him from the pungent and pecu-
liar smell of its oxide.   For  the mode in
which  he extracted it, see Iridium.
  Its  oxide  may likewise be obtained in
small quantity by distilling with  nitre the
black powder left after dissolving platina ;
   Vol.  U.
when at a low red heat an apparently oily
fluid sublimes into the neck of the retort,
which on cooling concretes into a solid, co-
lourless, semi-transparent mass. This being
dissolved in water, forms a concentrated so-
lution of oxide  of osmium.   'This solution
gives a dark stain to the skin, that cannot be
effaced.    Infusion of galls presently  pro-
duces a purple  colour in it, which soon af-
ter becomes of a deep vivid blue.  This is
the best lest  ofthe oxide.  With pure am-
monia it becomes yellow, and slightly so
with carbonate  of soda.  With lime it forms
a bright yellow solution ; but it is not affec-
ted either by chalk or by pure  magnesia.
The solution with lime gives a  deep red
precipitate with galls, which is turned blue
by acids.   It  produces no effect on solution
of gold or platina; but precipitates lead of
a yellowish-brown, mercury of a white, and
muriate of tin ofa brown colour.
   Oxide of osmium becomes of adark colour
with alcohol,  and  after some time separates
in the form of black  films, leaving the al-
cohol without colour. The same effect is
produced by ether, and much more quickly.
   It parts with its oxygen to all the metals
except gold and platina.  Silver  kept in  a
solution of it some time, acquires  a  black
colour,  but does not deprive it entirely of
smell.  Copper, tin,  zinc, and phosphorus
quickly produce  a black or gray powder,
and deprive the solution of smell, and ofthe
property of turning galls blue.  This black
powder, which consists of the metallic os-
mium, and the oxide ofthe metal employed
to precipitate it, may be dissolved in nitro-
muriatic acid, and then becomes blue with
infusion of galls.
   If the pure oxide dissolved in water be
shaken with mercury, it soon loses its smell,
and the metal forms a perfect amalgam. By
squeezing the superfluous mercury through
leather, and distilling off the rest, a dark gray
or blue powder is left, which is the osmium.
   Exposed to a strong heat in a cavity in a
piece of charcoal, it does not melt; nor is  it
volatile, if oxidation be carefully prevented.
With copper and with gold it forms mallea-
ble alloys, which are easily dissolved in ni-
tro-muriatic acid,  and afford by distillation
the oxide of osmium.  The pure metal, pre-
viously  heated, did not appear to be acted
upon by acids.  Heated in a silver cup with
caustic alkali, it combined with itrand gave
a yellow solution, similar to that from which
it was procured.   From this solution acids
separate the oxide of osmium. - Phil. Trans.
   * Ossifications. The deposition of calca-
reous phosphate or carbonate on tjie soft so-
lids of animal bodies ;  as in the pineal gland,
lungs, liver, &c*   See Pulw. Concretions,
   * Oxalates.  Compounds ofthe salifiable
bases with oxalic acid.  See Acid (Oxalic),
and the bases.*
   * QxALie Acid.  Thi»s acid is  described
                 29 
OXY                                  OXY
under Acid  (Oxalic).  It is found in the}
state of oxalate of lime in the  roots of the
following plants:—Alkana, apiuin, bistorta,
carlina acaulis, curcuma,  dictamnus albus,
fceniculum, gentiana rubra, vincetoxicum,
lapathum,  liquiritia, mandragora, ononis,
iris florentina, iris nostras, rheum, saponaria,
scilla, sigillum salomonis, tormentilla,  Vale-
riana, zedoaria,  zingiber.   And in the fol-
lowing barks :—berberis,   cassia  fistularis,
canella alba, cinamomum,  cascarilla,  cassia
caryophyllata, china,  culilavan,  frangula,
fraxinus,  quassia, quercus, simaruba, lignum
sanctum, ulmus.   In the state of binoxalate
of potash, it exists in the leaves ofthe oxalis
acetosella,  oxalis corniculata, different spe-
cies of rumex, and geranium acidum.
  The juice ofthe cicer parietinum is said
to be  pure  oxalic acid.*
  Oxidation. The process of converting
metals, or other  substances, into oxide*,  by
combining  with them  a certain portion of
oxygen.  It  differs from acidification in the
addition  of oxygen not betng sufficient to
form an acid with the substance oxided.
  Oxidks.  Substances combined with oxy-
gen, without  being in the state of an acid.
  Oxygen Gas.  This gas was obtained by
Dr. Priestley  in 1774, from red oxide of mer-
cury exposed to a burning lens, who observ-
ed its distinguishing properties of rendering
combustion more vivid and eminently sup-
porting life-  Scheele obtained it in different
modes in 1775 ;  and in  the same year La-
voisier, who had begun, as he says, to sus-
pect the absorption of atmospheric air, or of
a portion of it, in the calcination of metals,
expelled it from the red oxide of mercury
heated in a retort.
  Oxygen gas forms about a fifth  of our at-
mosphere,  and its base is very abundant in
nature.  Water contains 88.88per cent  of it j
and it exists  in  most vegetable and animal
products, acids,  salts, and  oxides.
  This gas may be obtained from  nitrate of
potash, exposed to a red heat in a coated
glass  or earthen  retort, or  in a gun-barrel;
trom  a pound of which about  1200  cubic
inches may be obtained ;  but this is liable,
particularly toward the end of the process, to
a mixture of nitrogen.  It  may be expelled,
as already  observed, from the red oxide of
mercury, or  that of lead; and still better
from the black oxide of manganese, heated
red-hot in  a gun-barrel,  or  exposed to a
gentler heat  in a retort with half its weight,
or somewhat  more, of strong sulphuric add.
To obtain it of the greatest purity, how ever,
the chlorate  of potash is preferable to any
other substance, rejecting the portions  that
first  come over as being debased with the
atmospheric air in the retort.   Grow ing ve-
getables, exposed to the solar light,give out
oxygen gas ; so  do leaves laid on  water in
similar  situations, the green  matter  that
forms in water, and some  other substances.
   Oxygen  gas has  neither smell nor taste.
Itssp.gr. is 1.1111; 100 cubic inches weigh
33.88 gr.   It is a little heavier than atmos-
pheric air.  Under great pressure water  niav
be made to take up about half its bulk. It
is essential to the support of life. an animal
will live in it a considerable time longer than
in atmospheric air; but its respiration be-
comes hurried and laborious  before  the
whole is consumed, and  it dies, though  a
fresh animal of the same kind can still sus-
tain life tor a certain time in the residuary air.
   Combustion is  powerfully supported by
oxygen gas.  Any  inflammable substance,
previously  kindled, and introduced into it,
burns  rapidly and vividly.  If an iron or
copper wire be introduced into a  bottle of
oxygen gas, with a bit of lighted touchwood
or charcoal at the end, it will burn with  a
bright light,  and throw  out a number of
sparks.  The bottom of the bottle should be
covered with  sand, that these sparks may not
crack it.  If  the  wire coiled up in a spiral
like a corkscrew, as it usually  is in this ex-
periment, be moved with  a jerk the instant
a melted globule is about to  fall,  so as to
throw it against the side ofthe glass, it will
melt its way through in. an instant, or, if the
jerk be less violent, lodge itself in  the  sub-
stance of the glass.  If it be performed  in a
bell glass, set in a plate filled with water, the
globules will frequently  fuse the  vitreous
glazing of the plate, and unite  with it so us
not to be separable  without detaching the
glaze, though it has passed through perhaps
two inches of water.
   Oxygenation.  This word is often used
instead of oxidation, and  frequently con-
founded with it; but it differs  in  being of
more general import, as every union with
oxygen, whatever the product may be, is an
oxygenation: but oxidation takes place only
when an oxide is formed.
   Oxymel.  A  compound of  honey  and
vinegar.
   * Oxr.wi'RiATic Acid.  Chlorine.*
   * OxYniussic Acid.  See Anu (Chlobo-
prussic).* 
PAI
 *  P AINTS.  In the Philosophical  Tran-
   1    sactionsfor 1815. Sir H. Davy  has
 communicated the results of some interest-
 ing researches, which he had made at Rome,
 on the colours used by the ancient artists.
   He found the reds  to be minium, ochre,
 and cinnabar.
   Tiie yellows were ochre,  orpiment,  and
 massicot.
   The  blues were formed from carbonate
 of copper, or cobalt, vitrified with glass.
   The purples were made of shellfish, and
 probably also from madder and  cochineal
 lakes.
   l he blacks and browns were lamp-black,
 ivory-black, and ores of iron and mang-anese.
   The whites were chalk, white  clay,  and
 ceruse.
   The  Egyptian azure,  the  excellence of
 which is proved by its duration for seventeen
 hundred years, may be easily and cheaply
 made.  Sir H.  Davy found, that 15 parts
 by weight of carbonate of soda, 20 of pow-
 dered opaque flints, and 3 of copper filings,
 strongly heated together for two hours, gave
 a substance of exactly the same tint, and of
 nearly the same  degree of fusibility,  and
 which when powdered, produced a fine deep
 sky-blue.
   He conceives, that next to coloured frits,
 the most permanent pigments are those fur-
 nished by the peroxides, or persalts, such
 as ochres, carbonates of copper, patent yel-
 low (submuriate of lead), chromate of lead,
 arsenite of copper, insoluble  chloride of
 copper, and sulphate of barytes.
   M.  Merime has inserted a note very in-
 teresting to painters in the Annates de Chimie
 et Phys. for June 1820.  When carbonate
 of lead is exposed tor some time to vapours
 of sulphuretted hydrogen, it becomes black,
 beingconvertedinto a sulphuret. This white
 pigment, employed with oil, and covered
 with a varnish, which screens it from the air,
 may be preserved for many hundred years, as
 the paintings of the 15th century prove. But
 when the varnish is abraded or decays, the
 whites of ceruse are apt  to contract  black
 specks and spots, which ruin fine paintings.
 Miniatures in  water colours are frequently
 injured  in this way.  M. Thenard was re-
 quested to occupy himself with the means of
 removing these  stainS, without injuring the
 rest ofthe picture. After some trials, which
 proved that the reagents which  would ope-
 rate on sulphuret of lead, would equally at-
tack the texture ofthe paper, as well as other
 colours, he recollected, that among the nume-
 rous phenomena which his discovery of oxy-
genated water had presented to him, he ob-
served the property it possessed, of convert-
PAL
P
 ing instantly the black sulphuret of lead intp
 the white sulphate of the same metal.  He
 gave a portion of water, containing about five
 or six times its volume of oxygen, to an ar-
 tist who had a fine picture of Raphael spot-
 ted black.  On  applying  a few  touches of
 his pencil, he perceived the s'ains vanish as
 if by enchantment,  without  affecting the
 other colours in the slightest degree.*
   Palladium.   This is a new metal,  first
 found by Dr.  Wollaston associated with pla-
 tina, among the  grains of which he supposes
 itB ore to exist, or an alloy of it with iridium
 and osmium, scarcely  distinguishable from
 the  crude platina, though it is harder and
 heavier.
   If crude platina be dissolved in nitro-mu-
 riatic acid, and precipitated with a solution
 of muriate of ammonia in hot water ; the
 precipitate washed, and the water added to
 the remaining solution, and a piece of clean
 zinc be immersed in this liquid, till no far-
 ther action on it takes place; the precipitate
 now thrown down will be a black powder,
 commonly consisting of platina,  palladium,
 iridium, rhodium, copper, and lead.  The
 lead and copper may be separated by dilute
 nitric  acid.  The remainder being then di-
 gested in nitro-muriatic acid, and common
 salt, about half the weight ofthe precipitate,
 added on the solution, on evaporating this to
 dryness by a gentle heat, the result will be
 triple salts of muriate of soda with platina,
 palladium, and rhodium.  Alcohol will dis-
 solve the first and second of these; and the
 small portion of platina may be precipitated
 by sal ammoniac.  The solution being dilut-
 ed, and prussiate of potash added, a precipi-
 tate will be thrown down, at first ofa deep
 orange, and afterward changing green. This
 being dried, and heated with a little sulphur
 before the blow-pipe,  fuses into a globule,
 from which the sulphur may be expelled by
 exposing it to the extremity of the flame,
 and the  palladium will remain spongy and
 malleable.
  It may likewise be obtained  by dissolving
 an ounce of nitrate of potash in five  of mu-
 riatic acid, and in this mixture  digesting the
 compound precipitate mentioned above. Or
 more simply by adding to a solution of crude
 platina, a solution of prussiate of mercury,
 on which a flocculent precipitate will gra-
 dually be formed, of a  yellowish-white, co-
 lour.  This is  prussiate of palladium, from
 which the acid may be expelled by heat.
  Palladium is of a grayish-white  colour,
 scarcely  distinguishable from platina, and
 takes a good polish.  It is ductile and very
malleable ; and being reduced into thin slips
is flexible, but not very elastic. Its fracture 
PAS
PEA
is fibrous, and in diverging stria, showing
a kind of crystalline arrangement. In hard-
ness it is superior to wrought iron.  Its sp.
grav. is from 10.9 to 11.8.   It is a less per-
fect conductor of caloric than most metals,
andlessexpansible, though in this it exceeds
platina.  On exposure to a strong heat  its
surface tarnishes a little, and becomes blue;
but an increased heat brightens it again.   It
is  reducible per se.   Its fusion  requires a
much higher heat than that of gold; but
if touched whiie hot with a small bit of sul-
phur, it runs like zinc.  'The sulphuret is
whiter than the metal itself, and extremely
brittle.
  Nitric acid soon acquires a fine red colour
from palladium, but the quantity it dissolves
is small.  Nitrous acid act s on it more quick-
ly and powerfully.  Sulphuric acid, by boil-
ing, acquires a similar colour,  dissolving a
small portion.  Muriatic acid acts much  in
the  same manner.  Nitro-muriatic acid dis-
solves it rapidly, and assumes a deep red.
   Alkalis and earths throw down a precipi-
tate from  its solutions generally ofa fine
orange colour;  but it is partly  redissolved
in an excess of alkali.   Some ofthe neutral
salts, particularly those of potash, form with
it triple compounds, much more soluble in
water than those of platina, but insoluble in
alcohol.
   Alkalis act on palladium even in the me-
tallic state; the contact of air, however, pro-
 motes their action.
   A neutralized solution of palladium is pre-
 cipitated of a dark orange or brown by re-
 cent muriate of tin; but if it be in such pro-
 portionsas to remain transparent, it is chang-
 ed to a beautiful emerald-green. Green sul-
 phate of iron precipitates the palladium in a
 metallic stale.  Sulphuretted hydrogen pro-
 duces a dark brown precipitate; prussiate of
 potash an olive  coloured; and prussiate of
 mercury a yellowish-white. As the last does
 not precipitate platina, it is an excellent test
 of palladium. This precipitate is from a neu-
 tral solution in nitric acid, and detonates at
 about 500° of Fahr.  in a manner similar  to
 gunpowder. Fluoric, arsenic,  phosphoric,
 oxalic, tartaric, citric, and some other acids,
 with their salts, precipitate  some of the so-
 lutions of palladium.
    All the metals except gold, silver, and
 platina, precipitate it in the metallic state.
  , * Paste. A glass made in imitation ofthe
 gems. M. Douault-Wieland has lately given
 the following directions for making them.
    The base of all artificial stones, is a com-
 pound of silex,  potash, borax, red oxide of
 lead, and sometimes arsenic.  Pure boracic
 acid, and colourless quartz should be used.
 Hessian crucibles are better than those of
 porcelain.  The fusion should be continued
 in a potter's furnace for 24 hours ; the more
 tranquil and continued it is, the denser the
 paste and the greater its beauty.
      Paste*.
Rock crystal,
Minium,
Potash,
Borax,
Arsenic,
 1.
4056 gr.
6300
2154
 276
   12
Ceruse of Clichy, —
Sand,            —
  Topaz
Very white paste,
Glass of antimony,
Cassius purple,
 2.   3.   4.
 —  .1456 ^600
 ■_-  5.U8  —
1260 1944 1260
 360  216  360
   12     6  —
8508  —  8508
3000  —   —
   No. 1. No. 2.
  • 1008  3456
      43   —
        1   —
Peroxide of iron (saffron of
  Mars),                       —    36
  Ruby.—Paste 2880, oxide of manganese
72.  Emerald.—Paste 4608, green oxide of
copper 42, oxide of chrome 2.   Sapphire.—
Paste 4608, oxide of  cobalt 68, fused for 30
hours.   Amethyst.—Paste  4608,  oxide of
manganese 36, oxide of cobalt 24, purple of
Cassius 1.  Beryl.—Paste 3456, glass of an-
timony  24, oxide of cobalt  1$.   Styrian,
Garnet,  or  ancient carbuncle.—Paste 512,
glass of antimony 256, Cassius purple 2, ox-
ide of manganese 2.
  In all these mixtures, the substances should
be blended by sifting, fused very carefully,
and cooled very slowly, being left on the fire
from 24 to 30 hours.
   M. Langon gives the following recipes -.
   Paste.—Litharge  100,  white sand  75,
potash 10.   Emerald.—Paste 9216,  acetate
of copper 72, peroxide of iron 1.5. Amethyst.
—Paste 9216, oxide  of manganese from 15
to 24, oxide of cobalt 1.*
   * Pearl.  A  highly prized spherical con-
cretion, which is formed within certain shell-
fish. It has a bluish-white colour, with con-
siderable lustre and  iridescence. It consists
of alternating concentric layers of membrane
and carbonate  of lime.  I'o this  lamellar
structure the iridescence is to be ascribed.
Pearls are of course very soluble in acids.*
   * Paroasite.  Common Ae rvNOLnr..*
   * Pkahl Ash.  An impure potash, obtain-
ed by lixiviation, from the ashes of plants.*
   * Pearl Spar.  See Brown Spar.*
   * Peahlsto.ne.  A sub-species of indivi-
sible quartz  of Jameson and Mohs.
   Colour generally gray.   Massive, vesicu-
lar, and in coarse concretions, whose surface
is shining and very like pearl.  In the centre
 of these concretions, spheres of obsidian
 are frequently met  with.   Lustre, shining.
 Translucent on the edges.  Most easily fran-
 gible. , Soft.   Sp. gr. 2.24to 2.;>4.  Before
 the blow-pipe  it swells, and  passes into a
 frothy  glass.  Its constituents are,  silica
 75.25, alumina 12, oxide of iron 1.6, potash
 4.5, lime 0.5, water  4.5.—Klaproth.  It oc-
 curs in  great beds  in  clay-porphyry  near
 Tokay in Hungary,  and near Sandy Brae in
 Ireland.*
    * Pearl Sinter,  or Fiorite.  A variety
 of siliceous sinter.   Colours white and gray.
 In imitative  shapes.  Glistening ; between 
PET                                 PEW
resinous  and pearly.  In  thin concentric
concretions. Translucent.  Scratches glass,
but less hard than quartz.  Brittle.  Sp. gr.
1.917.  It is infusible before the blow-pipe.
Its  constituents  are, silica 94, alumina 2,
lime 4. — Santi.  It has been found on vol-
canic tuff on the Vicentine.*
  * Peas i one. A sub-species of limestone.*
  * Pechblende.   An ore of uranium,*
  * Pirchloric Acid,   See Acid (Muri-
atic).*
  Pericardium  (Liquor  of tre).   The
constituents of the liquor pericardii appear
to be
Water,    -     92.0
Albumen,     -    5.5
                      f"  The proportion
Mucus,     -     2.0 J of these substances
Muriate of soda.   0.5*S is somewhat coll-
                      ie jectural.

                 100.0
  *  Peridot.   Ciikisolite.*
  Pi:i:late Salt and  Acid.  See   Acid
(Phosphoric).
   "  Perlateh Acid, or Ouretic.   Biphos-
phate  of soda.*
  Pm   (Ba'.sam  of).  This  substance is
obtained from the myroxyion peruiferum,
which grows  in the warm  parts of  South
America.  The tree is full of'resin, and the
balsam is obtained by boiling the twigs in
water.   It has the consistency of honey, a
brown colour, an agreeable smell, and a hot
acrid taste.
   P*ri vian Bark.  See  Cinchona.
   *  Petalite. A mineral discovered in the
mine of Uto in Sweden by  M. D'Andrada,
interesting, from its analysis by M. Arfwed-
son  having led to the knowledge of  a new
alkali. Externally it resembles white quartz.
but it has a twofold cleavage, parallel to the
sides ofa rhomboidal prism ; two of which
parallel to each other are splendent, and the
other  two are dull.   Sp. gr. 2.45.   On mi-
 nute inspection, a pinkish hue may be dis-
 cerned in the v. hite colour.  It scratches
 glass,  but may be raised by a knife.  It is
scarcely fusible by the blow-pipe, acquiring
merely a glazed surface, full of minute bub-
 bles.  Wlien  reduced to  a fine powder, it
appears as white as snow.   Placed in nitric
 acid, sp. gr. 1.45, it loses its white colour,
and changes to a dingy hue ; the acid at the
same time becomes clouded. The same acid,
somewhat dilute, dissolves it without effer-
 vescence, at a boiling heat. Its constituents,
 by M. Arfwedson, are, silex 79.212, alumina
 17.225, lithia  5.761.  1'here is here  an ex-
 cessof2.198 above the hundred parts, which
 M. Arfwedson says, he  does not know how
 to account for.  M. Vauquelin found 7 per
 cent of  lithia, in  some pure specimens  of
 petalite which M. Berzelius sent him.  Dr.
 Gmelin, as well as M. Arfwedson, state the
 sp.  gr.  at 2.42.  Borax  dissolves it with
facility,  The bead is transparent and co-
lourless.  Nitre,  fused  with pure petalite,
does not betray  the presence of any man-
ganese ;  whence we may infer that it con-
tains none of this metal.  By Dr. Gmelin'e
analysis, petalite is composed of, silica 74.17,
alumina  17.41, lithia 5.16, lime 0.32. mois-
ture 2.17, and loss 0.77.  He could detect
no manganese in pure specimens.  Those,
however, of a pale rose-red colour contain
it.*
   Petrifactions.  Stony matters, deposited
 either in the way of incrustation, or within
the cavities of organized substances, are call-
 ed petrifactions.  Calcareous  earth, being
 universally diffused and capable of solution
 in water, either alone, or by the medium of
 carbonic acid or sulphuric acid, which  are
 likewise very abundant, is deposited when-
 ever the water or the acid becomes dissipat-
 ed. In  this way we have  incrustations of
 limestone or of  selenite in the form of sta-
 lactites or  dropstones from the roofs of ca-
 verns, and in various other situations.
   The most  remarkable observations rela-
 tive to petrifactions are thus given by Kir-
 wan :—
   1. That those of shells are found on, or
 near, the surface ofthe earth';  those offish
 deeper; and those of wood deepest.  Shells
 in specie are found in immense quantities
 at considerable depths.
   2.  That those organic substances that re-
 sist putrefaction most, are frequently found
 petrified;  such as shells and  the  harder
 species of woods: on the contrary, those
 tha,t are aptest to putrefy are rarely found
 petrified;  as fish,  and the softer parts of an-
 imals, &c.
   . 3. That they are most commonly found
 in strata of marl, chalk,  limestone, or clay,
 seldom  in  sandstone, still  more rarely in
 gypsum;  but never in gneiss, granite, ba-
 saltes, or schorl; but they sometimes occur
 among  pyrites, and ores  of  iron, copper,
 and silver, and almost always consist of that
 species of earth, stone, or other mineral that
 surrounds them, sometimes of silex, agate^
 or carnelian.
   4. That they are found in climates where
 their  originals could not have existed.
   5. That those found in slate or clay  art
 compressed and flattened.
    * Petroleum. See Naphtha.*
   * Petrosilex. Compact feldspar.*
   * Petuntse.  Porcelain clay.*
   Pkwterv which is commonly called etain
 in France, and generally confounded there
 with true tin, is a compound metal, the ba-
 sis of which is tin. The best sort consists of
 tin alloyed with about a twentieth, or less^
 of copper or other metallic bodies,  as the
 experience of the workmen  has shown to
 be the most conducive to the improvement
 of its hardness and colour,  such as lead,
 zinc,  bismuth,  and antimony.  There  are 
PHO                                  p,i0
 tlu-ee sorts of pewter, distinguished by the
 names of plate, trifle, and ley-pewter. The
 first was formerly much used for plates and
 dishes; ofthe second are made the pints,
 quarts, and other measures of beer; and of
 the lev-pewter,  wine measures and large
 vessels.
   The best  sort of pewter  consists of 17
 parts of antimony to 100 parts of tin; but
 the French add a little copper to this  kind
 of pewter.  A very fine silver-looking metal
 is composed of 100 pounds of tin,  eight of
 antimony, one of bismuth, and four of cop-
 per.  On the contrary, the ley-pewter, bv
 comparing its specific gravity with  those of
 the mixtures of tin and lead,  must contain
 more than a fifth part of its weight of lead.
   * Piiarmacolite.  Arsenic bloom. Native
 arseniate of lime. SeeOiiKs.*
   * Phosfhoiikscence.  See Light.*
   * Phosphorite. A sub-species of apatite.
   1. Common phosphorite  Colour yellowish-
 white.  Massive and in curved lamellar con-
 cretions.   Surface drusy.   Dull.  Fracture
 uneven.  Opaque.  Soft and rather  brittle.
 It melts with  difficulty into a white  colour-
 ed glass.   When rubbed in an iron  mortar,
 or thrown on red-hot coals, it emits  a green
 coloured  phosphoric light. Its constituents
 are, lime 59, phosphoric acid 34,  silica 2,
 fluoric acid 1, oxide of iron 1.—Pelletier.
 It occurs  in crusts in Estremadura in Spain.
  2.  Earthy phosphorite.  Colour grayish-
 white.  It  consists of dull dusty particles. It
 phosphoresces on  glowing coals.  Its con-
 stituents are, lime 47, phosphoric acid 32.25,
 fluoric  acid 2.25, silica 0.5,  oxide  of iron
 0.75, water 1,  mixture of quartz and loam
 11.5.—Klaproth. It occurs in a vein  at Mar-
 marosch in Hungary. See Apatite.*
  * Phosphouis.  If phosphoric acid  be mix-
 ed  with  l-5th of its weight of powdered
 charcoal,  and the mixture  distilled at a mo-
 derate red heat, in a coated earthen retort,
 whose beak is partially immersed in  a basin
 of water, drops of a waxy looking substance
 will pass  over, and, falling into the water,
 will concrete into the solid, called phospho-
 rus.^ It must be  purified, by straining it,
 through a piece of chamois leather, under
 warm water.   It is yellow and semi-trans-
 parent.  It is as soft as wax, but fully more
 cohesive and ductile.  Its sp. gr. is 1.77. It
 melts at 90° F. and boils at 550°.
  In the atmosphere, at common tempera-
tures, it emits a white smoke, which, in the
 dark, appears luminous.  This smoke is aci-
  § M. Javal finds, that the bi-phosphate of
lime, obtained by digesting 5 parts of cal-
cined bone powder, with 2 parts of sulphu-
ric acid, is better adapted to yield phospho-
rus by ignition  with  charcoal in a  retort,
than pure phosphoric acid.  'The latter sub-
limes  in a great measure undecomposed.—
.9mi. de Clam, et Physique.  June 1820.
 dulous,and results from the slow oxygena.
 tion ofthe phosphorus. In air perfectly dry,
 however, phosphorus does not smoke, be-
 cause the acid which is formed is s >lid. and,
 closely incasing the combustible, screens it
 from the atmospherical oxygen.
   When phosphorus is healed in the air to
 about 148°, it takes fire,  and burns with a
 splendid white light, and  a copious dense
 smoke.  If the combustion take place with.
 in a large glass receiver, the smoke becomes
 condensed into  snowy  looking particles,
 which fall in a  successive shower, coating
 the bottom plate with a spongy white efflo-
 rescence of phosphoric acid.  This acid snow
 soon liquefies by the absorption of aqueous
 vapour from the air.
   When phosphorus is inflamed in oxygen,
 the light and heat are incomparably more
 intense; the former dazzling the eye, and
 the latter cracking the glass vessel.  Solid
 phosphoric  acid  results;  consisting of 1.5
 phosphorus 4- 2.0 oxygen.
   When  phosphorus is heated in  highly
 rarefied air, three products are formed  from
 it:  one  is phosphoric acid; one is a volatile
 white powder; and the third, is a red solid
 of comparative fixity, requiring a heat above
 that of boiling water for its fusion. The vol-
 atile substance is soluble in water, imparting
 acid properties  to it.   It seems to be phos-
 phorous acid.  'The red substance is proba-
 bly an  oxide of  phosphorus, since for its
 conversion into  phosphoric acid, it requires
 less oxygen  than phosphorus does.  See
 Acids (Phosphoric, Phosphorous, and Hi-
 roriiospiiouous.)
  Phosphorus and chlorine combine with
 great facility, when brought in contact with
 each other at common temperatures.  When
 chlorine is introduced into a retort exhaust-
 ed of air,  and containing  phosphorus, the
 phosphorus takes fire? and  burns with a pale
 flame, throwing off sparks; while a white
 substance rises and condenses on the sides
 ofthe vessel.
  If the chlorine be in considerable quanti-
ty,  as much as 12 cubic inches to a grain of
phosphorus, the latter will entirely disap
pear, and nothingbut the white powder will
be formed, into which about i> cubic inches
ofthe chlorine will be condensed. No new
gaseous matter is  produced.
  The powder  is a compound of phospho-
rus and  chlorine, first described  as a pecu-
liar body by Sir H. Davy in 1810; and vari-
ous analytical and synthetical experiments,
which he made with it, prove that it con-
sists of about 1  phosphorus,  and 6.8 chlo-
rine in  weight.   The equivalent ratio of 1
prime ofthe first 4- 2 ofthe second consti-
tuent, gives 1.5 to 9,  or 1 to 6.  It is the bi-
chloride of phosphorus.
  Its properties  are  very peculiar.  It is
snow-white, extremely volatile, rising in a
gaseous form, at atemperature much below 
PHO                                  PRO
that of boiling water.  Under pneumatic
pressure it may be fused, and then it crys-
tallizes in transparent prisms.
   It acts violently on  water, decomposing
it, whence result phosphoric  and muriatic
acids; the former from the combination of
tlve  phosphorus  with  the oxygen, and the
latter from that ofthe  chlorine with the hy-
drogen of the water.  It produces flame
when exposed to a lighted taper.  If it be
transmitted  through an ignited glass tube,
along with oxygen, it is decomposed, and
phosphoric acid and chlorine are obtained.
The superior fixity ofthe acid, above the
chloride, seems to give that ascendancy of
attraction to the oxygen  here, which the
chlorine possesses in most other cases. Dry
litmus paper exposed  to its vapour in a ves-
sel exhausted of air, is reddened. When in-
troduced into a vessel containing ammonia,
a  combination takes  place,  accompanied
with much heat,  and there results a com-
pound, insoluble in water, undecomposable
by acid or alkaline solutions, and possessing
characters analogous to earths.
   2. The protochloride of phosphorus was
first obtained in a pure state, by Sir H. Davy
in the year 1809.  If phosphorus be sublimed
through corrosiv e sublimate, in  powder, in
a glass tube, a limpid  fluid comes over, as
clear as water, and having a specific gravity
of 1.45.  It emits acid fumes when exposed
to the air, by decomposing the aqueous va-
pour.  If paper imbued with it be exposed
to the air, it becomes acid without inflam-
mation.  It does not redden dry litmus pa-
per plunged into it. Its vapour burns in the
flame of a candle. When mixed with water,
and heated, muriatic acid flies off, and phos-
phorous acid remains.  See Acid (Phospho-
hois). If it be introduced into a vessel con-
taining chlorine, it is converted into the bi-
chloride ; and if made to act upon ammonia,
phosphorus is produced, and the same ear-
thy-like compound  results, as that formed
by the bi-chloride and ammonia.
  When phosphorus is gently heated in the
protochloride, a part of it dissolves, and the
fluid, on  exposure to air, gives off acid
fumes, from its action  on atmospheric mois-
ture, while a thin film of phosphorus is left
behind, which usually inflames by the heat
generated from  the decomposition ofthe
vapour.  The first compound of this kind
was obtained  by MM. Gay-Lussac and The-
nard, by distilling phosphorus and calomel
together, in 1808;  and they imagined it to
be a peculiar combination of phosphorus,
oxygen, and muriatic acid. No experiments
have yet ascertained the quantity of phos-
phorus  which the protochloride  will dis-
solve.  Probably, says  Sir H.  Davy, a defi-
nite combination may be obtained, in which
the proportion of chlorine will correspond
to the proportion of oxygen in the oxide of
phosphorus. The subchloride would consist
of 3 phosphorus -}- 4.5 chlorine;  or of 2 4- 3.
  The compounds of iodine and phosphorus
have been examined by Sir H. Davy, and
M. Gay-Lussac.
  Phosphorus unites to iodine with the dis-
engagement of heat, but no light.  One part
of phosphorus and eight of iodine form a
compound of a red orange-brown  colour,
fusible at about 212°, ami volatile at a high-
er temperature.  When brought in conlt'
with water, phosphuretted hydrogen gas is
disengaged, flocks of phosphorus are pre-
cipitated, and the water, which is colour-
less, contains, in solution, phosphorous and
hydriodic acids.
  One part of phosphorus and 16  of iodine,
produce a crystalline matter of a grayish-
black colour, fusible at 84°.  The hydriodic
acid, produced by bringing it in contact with
water, is colourless, and  no  phosphuretted
hydrogen gas is disengaged.
  One part of phosphorus, and 24 of iodine,
produce a black substance partially fusible
at 115°.  Water dissolves it, producing a
strong heat, and the solution has a very deep
brown colour, which is not removed by keep-
ing it, for some time, in a gentle heat. With
1 phosphorus and 4 iodine, two compounds,
very different from each-other, are obtained.
One of them has  the same colour as that
formed of 1 phosphorus 4- 8 iodine, and
seems to lie the same with  it.  It melts at
217.5°, and when dissolved  in water, yields
colourless hydriodic acid, phosphuretted hy-
drogen, and phosphorus, which last preci-
pitates in orange-yellow  flocks.  The other
compound is reddish-brown, does not melt
at 212J,  nor at  a considerably higher tem-
perature. Water has no sensible action on it.
Potash dissolves it with the  disengagement
of phosphuretted hydrogen  gas; and when
aqueous chlorine is poured into the solution,
it shows only traces of iodine.  When heat-
ed in the open air, it  takes fire and burns
like phosphorus,  emitting white vapours,
without any iodine.  When tliese vapours
were condensed in a glass jar,  by M. Gay-
Lussac, he could perceive no iodine among
them. This red substance is always obtained
w hen the phosphorus  is in  the proportion
of I to 4 of iodine.  M.  Gay-Lussnc is inclin-
ed to consider it as identical with the red
matter, which phosphorus so often furnish-
es, and which is at present considered as an
oxide.  In whatever proportions the iodide
of phosphorus has been made, it exhales, as
soon as it is moistened, acid  vapours, owing
to the hydriodic acid formed by the decom-
position ofthe water.
  Such is the account of the iodides of phos-
phorus given by M Gay-Lussac   The com*
billing ratios by theory are, for the
Subiodide, 3.0 ?  iite-j-      ,  ■  <•,*-
  ■    ,  '    > 4-15.5 iodine, or 1 4- 5.16
 phosphorus, >                    '
Protiodide, 1.5 4- 15.5         1 4- 10.33
Deutiodide,l 5 -f 31.0         1 -f 20.66
  Phosphuretted hydrogen.  Of this compound
there are two varieties; one consisting o' a 
                PHO

grime of each constituent, and therefore to
Se called phosphurettedhydrogen; another,
in which the relation of phosphorus is one-
half less, to be called therefore subphos-
phuretted hydrogen
  1. Phosphurettedhydrogen. Into a small
retort tilled with milk  of lime, or potash-
water, let some fragments of phosphorus be
introduced, and let the heat of an Argand
flame be applied  to the bottom of the re-
tort, while its beak is immersed in the water
ota pneumatic trough.  Bubblesofgaiw.il
come  over, which explode spontaneously
with contact of air. It may also be procured
by  the  action of dilute  muriatic  acid on
phosphuret of lime. In order to obtain the
gas pure, however, we must receive it over
mercury. Its smell is very disagreeable. Its
sp. grav. is 0.9022.   100 cubic inches weigh
~7.$ gr.  In oxygen, it inflames with a bril-
liant white light. In common air, when the
gaseous bubble bursts the film of water, and
explodes,  there rises  up a ring of white
smoke, luminous in the dark. Water absorbs
about l-40th of its bulk of this gas, and ac-
quires a yellow colour, a bitter taste, and
the characteristic smell of the gas. When
brought in contact with chlorine, it deto-
nates with a brilliant green light; but the
products have  never been particularly ex-
amined.
  By transmitting a series of electric explo-
sions, through phosphuretted hydrogen, the
phosphorus is precipitated, and hydrogen of
the original gaseous volume remains. Hence
the composition ofthe gas maybe deduced
from a comparison of its specific gravity with
that of hydrogen.
      Phosphurettedhydrogen,    0.9022
      Hydrogen,                 0.0694
Phos.= difference of weight,       0.8328
  Tims we  perceive, that this compound
consists of 0.8328 phosphorus 4- 0 0694 hy-
drogen; or 124- 1; orl.54-0.125= 1.625,
which is the weight ofthe sum ofthe primes,
commonly called the weight  of its atom.
'The gas may be likewise conveniently ana-
lyzed by nitrous gas, nitrous oxide, or oxy-
gen.
  2. Suhphosphuretted hydrogen.  It was dis-
covered by Sir H. Davy in 1812. When the
v.ystaU'me hydrate of phosphorous acid  is
heated in a retort, out of the contact of air,
sold phosphoric acid is formed, and a large
quantity of subphosphuretted  hydrogen is
evolved.  Its smell is fetid, but not so disa-
greeably so as that ofthe preceding gas.  It
does not spontaneously explode like it, with
oxygen; but  at  a temperature of 300°, a
violent detonation takes place.  In chlorine
it explodes with a white flame.  Water ab-
go-bs \ of its volume of this gas. When po-
tash um is heated in it, its volume is doubled,
an.I the resulting gas is  pure hydrogen.
W'.ien  sulphur is sublimed  in 1 volume of it,
 i sulphuret of phosphorus is  formed,  and
                PHO

nearly 2 volumes of sulphuretted hydrogen
are produced. Now as the density of vapour
of phosphorus is 0.833, as appears both from
the above analysis of phosphureti< d hydro-
gen, and as also may be  inferred from Sir
H Davy's equivalent prime of phosphorus,
(see  Acid,  Phosphoric), the present gase-
ous compound results evidently from
2 volumes of hy-^ =  Q ^^    2 _ Q ^
   drogen,     >
And 1  volume}
   of  vapour of £- —               0.83J3
   phosphorus,  j                ------
                                 0.9721
which occupy only one volume -, whence the
specific gravity of this gas is 0 9721; and it
consists of 2 primes of hydrogen = 0.25 4-
one of phosphorus =» 1.5 = 1.75; being the
same weight with the prime of azote
   It  is probable that phosphuretted hydro.
gen  gas sometimes contains the subphos.
phuret and common hydrogen mixed with it.
   " 'There is not, perhaps," says Sir H. Da
vy, " in the whole series of chemical phe-
nomena, a more beautiful illustration of the
theory of definite proportions, than that of-
fered in the decomposition of hydrophos-
phorous acid into phosphoric  acid, and hy-
drophosphoric gas.
   " Four proportions of the acid, contain
four proportions of phosphorus and four of
oxygen; two proportions of  water, contain
four proportions of hydrogen and two of ox-
ygen, (all by volume). The six proportions
of oxygen  unite to three  proportions of
phosphorus to  form three  of  phosphoric
acid,- and the four proportions of hydrogen
combine with  one of phosphorus to form
one  proportion of  hydrophosphoric gas;
and there are no other products."—Elements,
p. 297.   The reader will observe, that his
hydrophosphoric gas, is our subphosphu-
retted hydrogen.
   Phosphorus  and  sulphur are capable of
combining. They may be united by melting
them together in a tube exhausted  of  air,
or under water. In this last case, they must
be used in small quantities;  as, at the mo-
ment of their action, water is decomposed,
sometimes with explosions.  'They unite in
many proportions.  The most fusible com-
pound is that of one and a half of sulphur to
two of phosphorus.  This remains liquid at
40° Fahrenheit.  When solid its  colour is
yellowish-white.  It  is  more  combustible
than phosphorus, and distils undecompoun-
ded at a strong heat.  Had it consisted of-
sulphur 4- 3 phosphorus,  we  should have
had a definite compound of 1 prime of the
first 4- 2 of the second constituent.  This
proportion frnis the best composition fot
 phosphoric fire-matches or bottles.  A par-
ticle of it attached to a brimstone ;natch, in-
 flames when gently rubbed against a surface
 of cork or wood. An oxide made by heating
 phosphorus in a narrow  mouthed phial with
 an ignited wire, answers the same purpose. 
PIC
PIC
 The phial  must be  kept  closely corked*
otherwise  phosphorous  acid is speedily
formed.
  Phosphorus is soluble id oils, and com- *
municates to them the property of appear-
ing luminous in the dark. Alcohol and ether
also dissolve it, but more sparingly.
  When swallowed  in the quantity  of a
grain, it acts as a poison. Azote dissolves a
little of it, and has its  volume enlarged by
about l-40th.  See Eudiometer.*
  * Phosphorus (of Baldwin).  Ignited mu-
riate of lime.*
  * Phosphorus (of Canton). "Oyster shells
calcined with sulphur.*
  * Phosphorus (of Bologna).  See  Light.
Sulphate of barytes.*
  * Phosphuhet.  A compound of phospho-
rus, with a combustible or metallic oxide.*
  Phlooisitcatf.d Air.  See Nitrooex.
  Phlogisticatkd Alkali. Ferroprussiate
of potash.  See Acid (Prussic).
  * Phlogiston.  See Combustion.*
  * Phtsalite or  Ptrophtsalite.   Colour
greenish-white. Massive.  In granular con-
cretions.  Splendent in the cleavage, which
is perfect, and as in topaz. Fracture uneven.
Translucent on  the  edges. As hard as to-
paz.  Sp.  gr.  3.451.  It whitens with the
blow-pipe.  Its constituents are, alumina
57.74, silica 34.36, fluoric  acid  7.77.  It is
found in granite at Finbo, in Sweden.  It is
a sub-species of prismatic topaz .—Jameson.*
  * Picromel. The characteristic principle
of bile.  If sulphuric acid,  diluted with five
parts of water,  be mixed with fresh bile, a
yellow precipitate will fall.  Heat the mix-
ture, then leave it in repose, and decant off
the clear part.  What remains was formerly
 called resin of bile, but it is a greenish com-
pound   of sulphuric  acid and picromel.
Edulcorate it with water, and digest with
carbonate of barytes.   The picromel now
liberated will  dissolve in the  water.   On
evaporating this  solution, it is obtained in
a solid  state.  Or by dissolving  the green
sulphate  in alcohol, and  digesting the so-
lution over carbonate  of potash till it cease
to redden litmus paper, we obtain the pic-
romel combined with alcohol.
  It resembles inspissated  bile. Its colour is
greenish-yellow; its taste is intensely bitter
at  first, with a succeeding impression of
 sweetness.  It is not affected by  infusion of
 galls, but the salts  of iron and subacetate
 of  lead precipitate it from its aqueous solu-
 tion. It affords no ammonia by  its destruc-
tive  distillation.  Hence, the  absence of
 azote is inferred, and the peculiarity of pic-
 romel.*
   * Picrotoxia. The bitter and poisonous
 principle of cocculut indicus, the fruit ofthe
 menispermum cocculus.  To the filtered de-
 coction of these berries, add acetate  of lead,
 while any precipitate falls. Filter and eva-
porate  the liquid  cautiously to the consist-
   V©L. II.
ence of an extract.  Dissolve In alcohol of
0.817, and evaporate the solution to dryness.
By repeating the solutions and evaporations,
we at last obtain a substance equally solu-
ble in water and alcohol.   The colouring
matter may be removed by agitating it with
a little water.  Crystals of pure  picrotoxia.
now fall,  which may be  washed with a lit-
tle alcohol.
  The crystals are four-aided prisms, of a
white  colour, and  intensely bitter  taste.
They are  soluble in 25 times their weight
of water, and  are not  precipitable by  any
known  re-agent.  Alcohol, sp.  gr.  0.810,
dissolves  one-third of  its weight of picro-
toxia. Pure sulphuric ether dissolves 2-5ths
of its weight.
  Strong sulphuric acid dissolves it, but not
when much diluted. Nitric acid converts it
into oxalic acid. It dissolves and neutralizes
in acetic acid, and falls when this is satu-
rated with an alkali.   It  may therefore be
regarded  as a vegeto-alkali itself. Aqueous
potash  dissolves it, without evolving any
smell of ammonia. It acts as an intoxicating
poison.
  Sulphate of picrotoxia must be formed by
dissolving picrotoxiain  dilute sulphuric acid;
for the strong acid chars  and destroys it.
The solution crystallizes  on cooling.  The
sulphate of picrotoxia dissolves in 120 times
its weight of boiling water.  The solution
gradually lets fall the  salt in fine silky fila-
ments disposed in bundles,  and possessed of
great beauty.  When dry, it has a white co-
lour, and  feek elastic under the  teeth, like
plumose alum.  It is composed of
       Sulphuric acid,     9.99     5
       Picrotoxia,   -    90.01    45
                       100.00
  Nitrate of picrotoxia.  Nitric acid, of the
specific gravity 1-38, diluted with twice its
weight of water, dissolves, when assisted by
heat, the fourth of its weight of picrotoxia.
When this solution is evaporated to one-half,
it becomes viscid, and on cooling, is convert-
ed into a transparent mass, similar to a solu-
tion of gum-arable. In this state the nitrate
of picrotoxia is acid, and exceedingly bitter.
If it be still further dried in a temperature
not exceeding 140°, it swells up, becomes
opaque, and grows at last perfectly white
and light, like calcined alum. If we keep h
in this state, at atemperaturel>i,elow that of
boiling  water, adding a little water occa-
sionally, the whole excess of acid exhales,
and the taste become purely bitter.  When
this salt is washed in pure water, the acid is
totally removed, and the picrotoxia is sepa-
rated in the state of fine white plates.
  Muriate of picrotoxia.  Muriatic acid, of
the specific gravity 1.145, has little action on
picrotoxia-  It dissolves it when assisted by
hea^ b\it does not become entirely saturated.
Five parts of (his acid,  dilutee] with thrfie
                  30 
PIT
PLA
times its weight of water, dissolve about one
part of picrotoxia at a strong boiling tempe-
rature. The liquor, on cooling, is converted
into a grayish crystalline mass, composed of
confused crystals. When these crystals are
well washed, they are almost destitute of
taste, and feel elastic under the teeth. They
dissolve in about 400 times their weight of
boiling water ;  but are almost entirely de-
posited on cooling.  The solubility is much
increased by the presence of an  excess of
acid.
  Acetate of picrotoxia.   Acetic  acid dis-
solves picrotoxia very well, and may be near-
ly saturated with it by the assistance of a
boiling heat.  On cooling, the acetate preci-
pitates  in well-defined prismatic  needles.
This acetate is soluble in 50 times its weight
of boiling water.  On cooling, it forms crys-
tals of great beauty, light, without any acid
smell, and much less bitter than picrotoxia
itself. It is decomposed by nitric acid, which
disengages the acetic acid.  Dilute sulphu-
ric acid has no  marked action on it.   It is
not so poisonous as pure picrotoxia.—Boul-
lay. Ann. de Chimie*
  * Pimel.'te.  A variety of steatite, found
at Kosemuts, in Silesia.*          \
  * Pinchbeck.   An  alloy of copper, in
which  the proportion of zinc is greater than
in brass.*
   * Pineal Concretions.  Matter ofa sto-
ny consistence is sometimes deposited in
the substance of the pineal gland, formerly
reckoned, from its position in the centre of
the brain, to be the seat of the soul, the in-
tellectual sanctuary.   These  concretions
were proved by Dr. Wollaston to be phos-
phate of lime.*
   ♦Finite.  Micarelle ofKirwan.  Colour
blackish-green.  Massive, in lamellar con-
cretions, and crystallized in an equiangular
six-sided prism; in the same figure trunca-
ted or bevelled, and in a rectangular four-
sided prism.  Cleavage shining;  lustre re-
sinous.  Fracture uneven.  Opaque.  Soft.
Sectile; frangible, and not flexible.   Feels
somewhat greasy.  Sp. gr. 2.95.  Infusible.
Its  constituents are,  silica  29.5, alumina
63.75, oxide of iron 6.75.—Klaproth.  It is
found in the granite of St. Michael's Mount,
 Cornwall ; and in  prophyry in  Glen-Gloe
 and Blair-Gowrie.*
   * Pistacte.  See Epidote.*
   * Pitch.   See Bitumen.*
   * Pi?ch Cc£l.  See Coal.*
   * Pitch Orb.  See Ores or uranium.*
    * Pitchstone.  A sub-species  of indivisi-
 ble quartz.  Colour green.  Massive; Vitreo-
 resinous lustre.  Feebly transparent on the
 edges.  Fracture conchoidal.. Semi-hard in
 a high degree.  Rather easily frangible. Sp.
 gr. 2.2 to 2.3.  It is fusible before the blow-
 pipe.  Its constituents  are, silica 73, alu-
 mina  14.5, fime 1, oxide of iron 1, oxide of
 manganese 0.1,  natron  1.75, water  8.5.—
 Klaproth.  It occurs in vensthat traverse
granite.  It  is  found in Arran, in  Mull,
Canna,  Skye,  and  in  the   Townland  of
Newry, where it was first observed by Mr
Joy ot  Dublin.*
  * Pitcoal.   See Coal.*
  * Punts.   See Vegetable Kingdom.*
  ♦Plasma. Colour between grass-green and
leek-green.  In angular pieces.  Glistening.
Fracture conchoidal.  Translucent.   Hard.
Brittle. Sp.  gr. 2.553. Infusible. Its consti-
tuents are, silica 96.75, alumina 0.25, iron 0.5,
loss 2.5.—Klaproth.   It occurs in beds asso-
ciaied with common calcedony. It is found
also among tl^e ruins of Rome.*
   * Pla»ter of Paris.  Gypsum.*
   Platina is one ofthe metals for the dis-
covery of which we are indebted to our
contemporaries.  Its ore has recently been
found  to contain, likew ise, four new  metals,
palladium, iridium,  osmium, and rhodium ;
which see ;  beside iron and  chrome.
   The crude  platina is to  be dissolved in
nitro-muriatic acid, precipitated by muriate
of ammonia, and exposed to a very violent
heat.  Then the acid and alkali are  expel-
led, and the metal reduced in an aggluti-
nated  state,  which  is rendered more com-
pact by pressure while red-hot.
   Pure or refined  platina  is by much the
heaviest body in nature.  Its sp. gr. is 21.5.
It is very malleable, though considerably
harder than either gold or silver;  and it
hardens much under the hammer.   Its  co-
lour on the  touch-stone is not  distinguish-
able from that of silver.  Pure platina  re-
quires a  very strong heat to melt  it ; but
when urged by a white heat, its parts will
adhere together by  hammering.  This pro-
perty, which is distinguished by the name
of welding,  is peculiar to platina and iron,
which resemble each other likewise in their
infusibility.
   Platina is  not altered by exposure to air ;
neither is it acted upon by the most concen-
trated simple  acids, even when boiling, or
 distilled from it.
   The aqua regia best adapted to the solu-
tion of platina, is composed of one  part of
the  nitric and three of the muriatic acid.
 The solution  does  not take place with  ra-
 pidity.  A  small quantity of nitric oxide is
 disengaged, the colour of the fluid becoming
 first yellow, and afterward of r. deep red-
 dish-brown, which, upon dilution with water,
 is found to be an intense yellow.   This so-
 lution is very corrosive, and tinges animal
 matters of  a  blackish-brown colour; it af-
 fords  crystals by evaporation.
   Count Moussin  Poushkin has given the
 following method of preparing malleable
 platina:
   Precipitate the  platina  from its solution
 by muriate of ammonia, and wash the preci-
 pitate with a little cold water.  Reduce it
 in a convenient crucible to the well-known
 spongy metallic texture, which wash  two
 or three times with boiling water,  to carry 
PLA
PLA
off any portion of saline matter that may
have escaped the action of the fire.  Boil
it for about half an hour, in as much water
mixed with one-tenth  part of muriatic acid
as will cover the mass to the depth of about
half an inch, in a convenient glass  vessel.
This will carry off any quantity of iron that
might still exist in the metal.  Decant the
acid water, and edulcorate, or strongly ig-
nite the platina.
  To one part of this metal take two parts
of mercury, and  amalgamate  in a  glass or
porphyry mortar. This amalgamation takes
place very readily.  The proper method of
conducting it is to take about two drachms
of mercury to three drachms of platina, and
amalgamate them together; and to this amal-
gam maybe added alternate small quantities
of platina and mercury, till the whole ofthe
two metals is combined.  Several pounds
may be thus amalgamated in a few hours,
and in the large way  a proper mill  might
shorten the operation.
  As soon  as the  amalgam of platina is
made, compress it in tubes of wood, by the
pressure of an iron  screw upon a cylinder
of wood adapted to the bore of the tube.
This forces the superabundant mercury from
the amalgam, and renders it solid.  After
two or three hours, burn upon the coals, or
in a crucible lined with charcoal, the sheath
in  which the amalgam is contained, and
urge the fire to a white heat; after  which
the platina may be taken out in a very solid
state, fit to be forged.
  Muriate of tin is so delicate a test of pla-
tina, that a single drop of the recent solu-
tion of tin in muriatic acid gives a bright red
colour to a solution of muriate of platina,
scarcely distinguishable from water.
  If the muriatic solution of platina be  agi-
tated with ether, the ether will become im-
pregnated with the metal.  This ethereal
solution is of a fine pale yellow, does not
stain the skin, and is precipitable by ammo-
nia.
  If the nitro-muriatic solution of platina
be precipitated by lime, and the precipitate
digested in sulphuric acid, a sulphate of pla-
tina will be formed.   A subnitrate may be
formed in the same  manner.  According to
M.  Chenevix,  the insoluble sulphite con
tains 54.5 oxide of platina, and 45.5 acid and
water;  the insoluble  muriate, 70 of oxide;
and the subnitrate, 89 of oxide; but the
purity ofthe oxide of platina in these is un-
certain.
  Platina does not combine with  sulphur
directly, but  is soluble by the alkaline sul.
phurets, and precipitated from its nitro-mu-
riatic solution by sulphuretted hydrogen.
  Pelletier united it  with  phosphorus,  by
projecting small bits of phosphorus on the
metal  heated to redness in a crucible ; or
exposing to a strong heat four parts each of
platina and concrete phosphoric acid with
one of charcoal powder.  The phosphuret
of platina is of a silvery-white, very brittle,
and hard enough to strike fire with steel.
It is more fusible than the metal itself and
a strong heat expels the phosphorus, whence
Pelletier attempted to obtain pure platina
in this way.  He found, however, that the
last portions of phosphorus were  expelled
with too much difficulty.
  Platina unites with most other metals.
Added in the proportion of one-twelfth to
gold, it forms a yellowish-white metal, high-
ly ductile, and tolerably elastic, so that Mr.
Hatchett supposed it might be used with
advantage for watch-springs, and other pur-
poses.  Its specific gravity was 19.013.
  Platina renders silver more hard, but its
colour more dull.
  Copper is much improved  by alloying
with  platina.  From  l-6th  to  l-25th, or
even  less, renders it of a  golden colour,
harder, susceptible ofa finer polish, smooth-
grained, and much less liable to rust.
  Alloys of platina  with tin and lead art
very apt to tarnish.   See Iron.
  From its hardness, infusibility,  and diffi-
culty of being acted upon  by most agents,
platina is of great value for making various
chemical vessels. These have, it is true, the
inconvenience of being liable to erosion
from  the caustic  alkalis and some  of the
neutral salts.
  * Platinum is now hammered  in  Paris
into leaves of extreme thinness. By enclos-
ing a wire of it in a little tube of silver, and
drawing this through a steel plate in the
usual way, Dr. Wollaston has succeeded in
producing  platinum wire  not exceeding
l-3000th of an inch in diameter.
  For some curious phenomena of its fu-
sion, see Blow-pipe.  There are two oxides
of platinum:—
  1.   The protoxide may  be obtained by
pouring  a  solution of neutral nitrate of
mercury into a dilute solution of muriate of
platinum.   A dark brown  or  olive-green
powder falls, which is acompound of calo-
mel  and the protoxide of platinum.  It
must be well washed, and then gently heated
so as to dissipate  the mercurial salt.  The
pure  black  protoxide now  remains.   100
grains of it, at a red heat, emit 12^ cubic
inches of oxygen, and become metallic pla-
tinum.  With enamellers'  flux it may  be
ignited without reduction.   This important
fact, as well as the discovery of this oxide
itself, is due to Mr. Cooper.  It would thus
appear that protoxide of platinum consists of
     Platinum,     100.000    22.625
     Oxygen,        4.423     1.000
  2.  The peroxide appears  to contain three
prime proportions. Berzelius obtained it by
treating, the muriate  of platinum with sul-
phuric acid, at a distilling heat, and decom-
posing the sulphate by aqueous potash. The
precipitated oxide is a yellowish-brown pow- 
PLA
P01
der, easily reducible by a red heat to the
metallic state.
  According to  Mr. E. Davy, the proto-
chloride is soluble in water;  while the bi-
chloride is insoluble.  If the common nitro-
muriatic solution be cautiously dried, and
heated to dull redness, washed with water,
and again dried, we obtain the bichloride,
apparently consisting of
    Platinum,  100, or 1  prime 23.73
    Chlorine, 37.93   2         9.00
  It has a dull olive-brown or green colour;
a harsh feel; and is destitute of taste and
smell.  Itis  not fusible by heat; nor is it
altered by exposure to the atmosphere. At
a full red heat  the chlorine flies off, and
platinum remains.
  According to  Mr. E. Davy, there are two
phosphurets and three sulphurets of plati-
num. See his excellent memoir in the Pldl.
Mag. vol. xl.
  The salts of platinum have the  following
general characters:—
  I.  Their solution in water is yellowish-
brpwn.
  2.  Potash  and ammonia determine the
formation of small orange-coloured crystals.
  3.  Sulphuretted hydrogen throws down
the metal in a black powder.
  Ferroprussiate Of potash, and infusion of
galls  occasion no precipitate.
  1. The sulphate of platinum  may be ob-
tained by passing a current of sulphuretted
hydrogen gas through the nitro-muriatic so-
lution. It should be washed and boiled once
or twice with nitric acid, to ensure its en-
tire conversion   into  sulphate.  It has  a
brownish-black  colour, and resembles the
carbonaceous crust left when sugar is de-
composed by heat.  It is brittle, easily pul-
verized, and has the lustre nearly of crystal-
lized blende. Its taste is acid, metallic, and
somewhat caustic.  It reddens litmus paper
slightly. It is deliquescent, and  soluble in
water, alcohol, and ether, as well as in mu-
riatic, n itric, and phosphoric acids. At a red
heat  it is resolved into metal.  It appears
from Mr. Davy's analysis to consist of
                                 Theory.
  Sulphuric acid,         26.3    2758
  Protoxide of platinum,  73.7    72.42
  This near coincidence is a verification of
the analysis. A  sulphate of potash and pla-
tinum is formed by neutralizing the sulphate
with a solution of potash, and exposing the
mixture for alittle to a boiling heat.  A gran-
ular substance resembling gunpowder is ob-
tained.  It  is tasteless, insoluble in water,
and possesses the lustre of blende. A soda-
sulphate may be formed  by a similar pro-
cess; as also an  ammonia-sulphate.
    Fulminating platinum has been lately dis-
covered by Mr.  Edmund Davy.  Into a solu-
tion ofthe sulphate in water, aqueous am-
 monia is poured, and the precipitate which
fjdls, being  washed, is put into  a matrass
with potash-ley, and boiled for some time.
It is then filtered, Washed, "and  dried.  A
brown powder is obtained, lighter than ful-
minating gold, which is the fulminating pla-
tinum.  It explodes violently  when heated
to 400° ; but does not detonate by friction
or percussion.   It is a non-conductor of
electricity.  With sulphuric acid it forms a
deep coloured solution.  Chlorine and mu-
riatic acid gas decompose it.   According to
Mr. E. Davy, it consists of
                              Nearly
  Peroxide of platinum, 82.5    2 primes
  Ammonia,            9.0    1
  Water,               8.5    2
  An important paper of Mr. Davy's on pla-
tinum has been recently read at the Royal
Society,  the details of which  are not yet
published.*
  * Platinum OnE.   See  Onss or  Plati-
num.*
  * Pleonaste.  Ceylanite.*
  •Plumbago.   See Graphite.*
  * Poisons.  Substances which, when ap-
plied to living bodies,  derange the vital
functions, and produce  death, by an action
not mechanical. The study of their nature,
mode of operation, and antidotes, has been
called toxicology. Poisons have been arrang-
ed into six classes:
  I.— Corrosive, or escharotic poisons.
  They are  so named because they usually
irritate,  inflame, and corrode  the animal
texture with which they come into contact,
Their action is in general more violent and
formidable than that of the other poisons.
The following list  from Orfila  contains the
principal bodies of this class:
  1. Mercurial preparations,-  corrosive sub*
limate; red oxide of mercury;  turpeth mi-
neral,  or  yellow subsulphatc of mercury ;
pernitrate of mercury; mercurial vapours.
  2. Arsenical preparations; such as white
oxide of arsenic, and its combinations with
the  bases, called  arsenites;  arsenic  acid,
and the arseniates; yellow and red sulphu-
ret  of arsenic; black oxide  of arsenic, or
fly-powder.
  3. Antimonialpreparations;  such as tartar
emetic, or cream-tartrate  of antimony; ox-
ide of antimony; kermes  mineral; muriate
of antimony; and antimonial wine.
  4. Cupreous preparations;  such as verdi-
gris; acetate of copper;  the cupreous sul-
phate,  nitrate, and  muriate;  ammoniacal
copper; oxide  of copper; cupreous soaps,
or grease tainted with oxide of copper; and
cupreous wines or vinegars.
  5. Muriate of tin.  .
  6. Oxide  and sulphate of zinc.
  7. Nitrate of silver.
  8. Muriate of gold.
  9. Pearl-white or the oxide of bismuth, and
the subnitrate of this metal.
  10.  Concentrated aculs ,• sulphuric, nitric,
phosphoric, muriatic, hydriodic-, acetic, &t. 
POI
POI
  11.  Corrosive alkalis,  pure or subcarbo-
nated potash, soda, and ammonia.
  12.  The caustic earths, lime and barytes.
  13.  Muriate and carbonate of barytes.
  14.  Glass and enamel powder.
  15.  Cantharides.
  H.—Astringent poisons.
  1. Preparations of lead, such as the ace-
tate, carbonate, wines sweetened with lead,
water impregnated  with  its oxide, food
cooked  in  vessels containing lead, sirups
clarified with subacetate of lead, plumbean
vapours.
  Ill —Acrid poisons.
  1. The gases,-  chlorine, muriatic acid,
sulphurous  acid, nitrous gas, and  nitro-mu-
riatic vapours.     .
  2. Jatropha manihot, the fresh  root, and
its juice, from which cassava is made.
  3.  The Indian ricinus, or Molucca wood.
  4. Scummony,  5. Gamboge.  6. Seeds of
palma Christi.  7. Elaterium.  8 Colocynth.
9. White hellebore root.  10. Black helle-
bore root.  11. Seeds of stavesacre. 12. The
wood and fruit ofthe ahovai of Brazil.  13.
Rhododendron chrysanthum.  14. Bulbs of
eolchicum, gathered in summer and autumn.
15. The milky juice of the convolvulus ar-
vensis, 16. Asclepias.  17. OZnanthe fistulo-
ea and crocata. 18. Some species of clematis.
19. Anemone pulsatilla. 20. Root of Wolf's-
bane. 21. Fresh roots  of Arum maculatum.
22. Berries and bark of Daphne Mezereum.
23.  The plant and emanations  of the rhus
toxicodendron. 24. Euphorbia  Officinalis.
25.  Several species of ranunculus, particu-
larly  the aquatilis. 26. Nitre, in a large dose.
27. Some muscles and other shell-fish.
  IV.—Narcotic and stupefying poisons.
   1.  The gases;  hydrogen, azote, and ox«
ide of azote.
  2.  Poppy and opium.
   3.  The roots of the solanum somniferum;
berries and leaves of  the solanum nigrum;
 those ofthe morel with yellow fruit.  4. The
 roots and leaves of the atropa mandragora.
 5.  Datura stramonium.  6. Hyosciamus, or
 henbane. 7. Lactuca virosa.  8. Paris quad-
 rifolia, or herb Paris.  9. Lauro-cerasus, or
 bay laurel and prussic acid.  10.  Berries of
 the yew tree.  11. Ervum ervilia;  the seeds.
 12. The seeds of lathyrus cicera.  13. Dis-
 tilled water of bitter almonds.   14. The ef-
 fluvia of many of the above plants.
   V.—Narcotico-acrid poisons.
   1.  Carbonic acid;  the  gas  of charcoal
 stoves and fermenting liquors. 2. The man-
 chineel. 3. Faba Sancti Ignatii.  4. The ex-
 halations and juice ofthe poison-tree of Ma-
 cassar, or Upas-Antiar.  5. The ticunas.  6.
 Certain species of Strychnos. 7. The whole
 plant,  Lauro-cerasus.  8.  Belladona, or
 deadly nightshade.  9. Tobacco.  10. Roots
 of white bryony.  11.  Roots of the Choero-
 phyllum silvcstre. 12. Conium maculatum,
 or spotted hemlock.   13. JEthusa cyna-
pium.  14. Cicuta virosa.  15. Anagallis ar
vensis.  16.  Mercurialis perennis.  17. Di-
gitalis purpurea.  18. The distilled waters
and oils of some of the above plants.  19.
The odorant principle  of some of them-
20.  Woorara  of Guiana.   21. Camphor.
22. Cocculus  Indicus.   23. Several mush-
rooms;  see Agaricus, and  Boletus.  24.
Secale cornutum.  25. Loliumtemulentum.
26.  Sium latifolium.  27.  Coriaria myrtiv
folia.
   VI.—Septic or putrescent poisons.
   1. Sulphuretted  hydrogen.  2.   Putrid
effluvia d"  animal  bodies.   3. Contagious
effluvia, or formites and miasmata; see Mias-
mata.   4. Venomous animals;  the viper,
rattlesnake, scorpion, mad dog, 8tc.
   I regret that the  limits of this work pre-
clude me from introducing a systematic view
ofthe mode of action of the principal sub-
stances in the above catalogue. Under Anti-
mony, Arsenic, Copper,  Lead, Mercury, Sil-
ver, pretty copious details are given of the
poisonous effects of their preparations, and.
ofthe best methods of counteracting them.
   Antidote for vegetable poisons.   M. Dra-
piez has ascertained, by numerous experi-
ments, that the fruit of the feuillea cordifolia,
is a powerful antidote "against vegetable poi-
sons.  He poisoned dogs with the rhus toxi-
codendron, hemlock, and mix vomica; and
 all those which  were left to the effects of
 the poison died, but  those  to which the
 above fruit was administered,  recovered
 completely, after a short illness.  To see
 whether the antidote would act in  the same
 way, applied externally to wounds into which
 vegetable poisons had been introduced, he
 took two arrows, which had been dipped
 into the juice ofthe manchenille, and slightly
 wounded with them two cats; to one of these
 wounds he applied a poultice, composed of
 the fruit of the feuillea cordifolia, while the
 other was left without  any application. The
 former suffered no inconvenience, except
 from the pain ofthe wound, which speedily
 healed; while the other,  in a short time,
 fell into convulsions, and died.  This fruit
 loses these valuable virtues, if kept two
 years after it is gathered.
   Dr. Chisholm states, that the juice of the
 sugar-cane is  the best antidote for arsenic.
   Dr. Lyman Spalding of  New  York an-
 nounces in a small pamphlet, that for above
 these fifty years, the Scutellaria Lateriflora
 has proved to be an infallible means for the
 prevention and cure  of the hydrophobia
 after the bite of rabid animals.  It is better
 applied as a dry powder, than fresh.  Ac-
 cording to the testimonies of several Ameri-
 can physicians, this plant, not yet received
 as a remedy in any European Materia Medi.
 ea, afforded perfect relief in above a thou-
 sand cases, as well in the human species, as
 in the brute creation, (dogs, swine, and ox-
 en).—Phil. Mag. lvi.  p. 151.* 
POll                                 POT
  * Polishing-Slatb.  See Clat.*
  * Pollen.  The powdery matter evolved
from the anthera  of  flowers.  'That  of the
date seems, from the  experiments  of Four-
croy and Vauquelin, to approach in its con-
stitution to animal substances ; that  of the
hazel-nut contains tannin, resin, much glu-
ten, and a little fibrin ; and that of the tulip
yielded to Grot thus the following constitu-
ents in 26 parts :
  Vegetable albumen,      -     20.25
  Malate of  lime, with trace of ~>    « ^q
    malate of magnesia,       5
  Malic acid,    -    -     -       1.00
  Malate of ammonia,         "^
  Colouring matter,           V.    1.25
  Saltpetre ?                  S   ----
                                26.00
  The principle in pollen, intermediate be-
tween gluten and albumen, has been named
by Dr. John, Pollenin.
  It is yellow, without taste and smell;  in-
soluble in water, alcohol, ether, fat, and vo-
latile oils, and petroleum.
  It burns with flame.  On exposure to air,
it assumes the smell  and taste of cheese,
and soon becomes putrid with disengage-
ment of ammonia.*
  * Paltchroite. The colouring matter of
saffron.*
  * Pompholix.  White oxide of zinc*
  * Ponderous Spar.  See  Heavt Spar.*
  * Porcelain Earth.  See Clay.*
  Pohcelaln is the most beautiful and the
finest of all earthen wares.
  The art of making porcelain is one of
those in which Europe has been excelled by
oriental nations.  The first porcelain that
was seen in Europe was brought from Japan
and China.  The whiteness, transparency,
fineness, neatness, elegance,  and even the
magnificence of this pottery, which soon be-
came the ornament of sumptuous tables,  did
not fail to excite the  admiration and indus-
try of Europeans.
  Father Entrecolles, missionary at  China,
sent home a summary description of the
process by which the inhabitants  of that
country make their porcelain-, and also a
small quantity of the materials which they
employ in its composition. He said, that the
Chinese composed their porcelain of two
ingredients, one of which is a hard stone or
rock, called by them petuntse, which they
carefully grind to a very fine powder ; and
the other, called by them kaolin, is a white
earthy substance, which they mix intimately
with the ground petuntse.
  Reaumur examined both  these  matters;
and having exposed them separately to a vio-
lent fire,  he  discovered, that the petuntse
had fused without addition, and that  the ka-
olin had given no sign of fusibility.  He af-
terward mixed these matters,  and  formed
cakes of them, which, by baking, were con-
verted into porcelain similar to that of Chi-
na.   See Kaolin, Petuntse, and Potteht.
  Porcelain of Reaumur.   Reaumur gave
the quality of porcelain to glass ; that is, he
rendered glass of a milky colour, semi-trans-
parent,  so hard as to strike fire with steel,
infusible, and of a fibrous grain, by means of
cementation.  The process which he pub-
lished is not difficult.  Common glass, such
as that of which wine bottles are made, suc-
ceeds best.  The glass vessel which is to be
converted into porcelain, is to be enclosed
in a baked earthen  case or seggar. The
vessel and  case are to be filled with a ce-
ment composed of equal parts of sand and
powdered gypsum or plaster; and the whole
is to be  put into a potter's  kiln, and to re-
main there during the-baking of common
earthenware; after which the glass  vessel
will be found transformed into such a mat-
ter as has been described.
  *  Porphtrt is a compound rock,  having
a basis, in which the other contemporaneous
constituent parts are imbedded. The base is
sometimes clay-stone, sometimes hornstone,
sometimes compact feldspar; or pitchstone,
pearlstone,  and  obsidian.  The imbedded
parts are most commonly feldspar and quartz,
which are usually crystallized, more  or less
perfectly, and hence they appear sometimes
granular.  According to Werner, there are
two distinct porphyry formations; the oldest
occurs in gneiss, in beds of great magnitude;
and  also in mica-slate and clay-slate.  Be-
tween Blair  in Athole  and Dalnacardoch,
there is  a very fine example ofa bed  of por-
phyry-slate in mica.  The second porphyry
formation is much more widely extended.
It consists  principally of clay porphyry,
while the former consists  chiefly of horn-
stone porphyry  and feldspar porphyry.
  It sometimes contains considerable repo-
sitories  of ore, in veins.  Gold, silver, lead,
tin, copper, iron, and manganese occur in
it;  but  chiefly in the newer porphyry, as
happens with the Hungarian mines.  It  oc-
curs in Arran, and in  Perthshire, between
Dalnacardoch and Tummel-bridge.*
  Portland Stone.   A compact sandstone
from the Isle  of Portland.  The cement is
calcareous.
   *  Potash, commonly called the vegetable
alkali, because it is obtained in an  impure
state by the incineration of vegetables.   It
is the hydrated deutoxide of potassium.*

 Table of the  saline  product of one thousand
   lbs. of ashes of the follawittg vegetables :—
             Saline products.

 Stalks of Turkey ?  19g ,b
   wheat or mais, y
 Stalks  of  sun-> g^g
   flower,       5
 Vine-branches,     162.6
 Elm,              166
 Box,               78 
POT
POT
Sallow,
Oak,
Aspen,
Beech,
Fir,
Fern cut in Au-
  gust,
Wormwood,
Fumitory,
Heath,
102
111
 61
219
132
116 $ or *^ according
    £   to Wildenheim.
748
360
115  Wilderheim.
  On these tables Kirwan makes the follow-
ing remarks : —
  1. Thatin general weeds yield more ashes,
and their ashes much more salt than woods;
and that consequently, as to salts ofthe ve-
getable alkali kind, as potash, pearl ash, ca-
shup, &c. neither America, Trieste, nor the
northern countries, have any advantage over
Ireland.
  2. That of all weeds fumitory produces
most salt, and  next to it wormwood.  But
if we attend only to the quantity of salt in a
given  weight  of ashes, the ashes of worm-
wood contain most. Trifolium fibrinum also
produces more ashes and salt than fern.
  The process for obtaining pot and pearl-
ash is given by Kirwan, as follows :—
  1. 'The weeds should be cut just before
they seed, then spread, well dried, and ga-
thered clean.
  2. They should be burned within doors
on  a grate, and  the ashes laid in a chest as
fast as they are produced.  If any charcoal
be  visible, it  should be picked out, and
thrown back into the fire.  If the weeds be
moist, much coal will be found.  A  close
smothered fire, which has been recommend-
ed  by some, is very prejudicial.
  3. They should be lixiviated with twelve
times their weight of boiling water.  A drop
of the solution of corrosive sublimate will
immediately discover when the water ceases
to take  up any more alkali.  The earthy
matter that remains is said  to be a good ma-
nure for clayey soils.
  4. The ley thus formed should be evapo-
rated to dryness in iron pans.  Two or three
at least of these should be used, and the ley,
as fast as it is concreted, passed from the
one to the other. Thus, much time issaved,
as weak leys  evaporate more quickly than
the stronger.  The salt thus procured is ofa
dark colour, and contains much extractive
matter, and being formed in iron pots, is
called potash.
  5. This salt should then be carried to  a
reverberatory furnace, in which the extrac-
tive matter is burnt off', and much ofthe wa-
ter dissipated : hence it generally loses from
ten to fifteen per cent of its weight.  Parti-
cular  care should be taken to prevent its
melting, as the extractive matter would not
then be  perfectly consumed, and the alkali
would form such a union with the earthy
parts as could  not easily be dissolved.  Kir-
wan adds this caution,' because Dr. Lewis
and Mr. Dossie have inadvertently directed
the contrary. 1'his salt thus refined is call-
ed pearl-ash, and must be the same as the
Dantzic pearl-ash.
  To obtain this alkali pure, Berthollet re-
commends to evaporate a solution of pot-
ash, made caustic by boiling with quicklime,
till it becomes of a thickish consistence, to
add about an equal weight of alcohol, and
let the mixture stand some time in a close
vessel.  Some  solid matter,  partly crystal-
lized, will collect at the bottom; above this
will be a small  quantity of a dark  coloured
fluid, and on the top another lighter.  The
latter, separated by  decantation,  is to be
evaporated quickly  in a silver basin in a
sand heat.  Glass, or almost any other metal,
would be corroded by the potash. Before
the evaporation has  been carried far,  the
solution is to be removed from the fire, and
suffered to stand at rest; when it will again
separate into two fluids. The lighter, being
poured off, is again to be evaporated with a
quick heat; and on standing a day or two
in a close vessel, it will deposite transparent
crystals of pure potash..  If the  liquor be
evaporated to  a  pellicle,  the potash will
concrete without regular crystallization. In
both cases a high-coloured liquor is separat-
ed, which is to be poured off;  and the pot-
ash must be kept carefully secluded from air.
   A perfectly pure solution of potash, will
remain transparent, on the addition of lime
water, show no effervescence with dilute
sulphuric acid,  and not give any precipitate
on blowing air from the lungs through it by
means of a tube.
   * Pure potash for experimental purposes,
may most  easily be  obtained by igniting
cream of tartar in a crucible, dissolving the
residue in  water, filtering,  boiling with a
quantity of quicklime, and after subsidence,
decanting the clear liquid, and evaporating
in a loosely covered silver  cspsule,  till  it
flows like oil, and then pouring it out on a
clean iron plate. A solid white cake of pure
hydrate of potash is thus obtained, without
the agency of alcohol. It must be immedi-
ately broken into fragments, and  kept in a
well-stoppered phial.
   As 100  parts of subcarbonate of potash
are equivalent to about 70 of pure concen-
trated oil of vitriol, if into a measure tube,
graduated into 100 equal parts,  we intro-
duce the 70 grains of acid, and fill up  the
remaining  space with water, then we have
an alkalimeter  for estimating  the value o'
commercial pearl ashes, which, if pure, will
require for 100 grains one hundred division'.
of the liquid to neutralize them.  If they
contain only 60 per cent of genuine suhcar?
bonate, then 100 grains will require only 60
divisions, and so on.  When the alkalimeter
indications are  required in pure or absolute
potash, such as constitutes the basis of nitre,
then we must use 102 grains of pure oil of 
POT
POT
 vUr&il, along with the requisite  bulk of
 water to  fill up  the  volume of the gradu-
 ated tube.
   The hydrate of potash, as obtained by the
 preceding process, is solid, white, and ex-
 tremely  caustic;  in minute quantities,
 changing the purple of violets and cabbage
 to a green, reddened  litmus to purple, and
 yellow tumeric to a reddish-brown.   It ra-
 pidly attracts humidity from the air, passing
 into the oil of tartar per deliquium of the old
 chemists;  a name,  however, also  given to
 the  deliquesced  subcarbonate.  Charcoal
 applied to the hydrate of potash at a cherry-
 red heat, gives birth to carburetted hydro-
 yen, and an alkaline subcarbonate; but at a
 heat bordering  on whiteness, carburetted
 hydrogen, carbonous  oxide, and potassium,
 are formed. Several metals decompose the
 hydrate of potash, by the aid of heat; par-
 ticularly potassium, sodium, and iron.  The
 fused hydrate of potash consists of 5.95 deu-
 toxide of potassium 4- 1.125 water = 7.075,
 which  number represents the compound
 prime  equivalent.  It is used in surgery, as
 the potential  cautery  for forming eschars;
 and it was formerly employed in medicine
 diluted with  broths as a  lithontriptic. In
 chemistry, it is very extensively employed,
 both in manufactures and as a reagent in an-
 alysis.  It is the basis of all the common soft
 soaps.   The oxides of the  following metal6
 are soluble in aqueous potash :—-Lead, tin,
 nickel, arsenic, cobalt, manganese, zinc, an-
 timony, tellurium, tungsten, molybdenum.
 Kor the sulphuret, see Sulphur.*
  * Potassium.  If a thin piece of solid hy-
 drate of potash,  be placed  between  two
 discs of platinum, connected  with  the ex-
 tremities ofa voltaic apparatus of 200 dou-
 ble plates, four inch square, it will soon un-
 dergo  fusion; oxygen will separate at the
 positive surface, and smull metallic globules
 will appear at the negative surface.  These
form the marvellous metal  potassium, first
 revealed to the world by Sir H. Davy, early
 in October 1807.
  If iron, turnings be  heated  to whiteness
 in a curved gun-barrel, and potash be melt-
 ed and made slowly to come in contact with
the turnings,.air being excluded, potassium
 will be formed, and will collect in the cool
part of the tube.  This  method of procuring
it was discovered by MM.  Gay-Lussac and
Thenard, in 1808.  It  may likewise be pro-
duced, by  igniting potash with charcoal, as
 M. Curaudau showed the same year.
  Potassium is possessed of very extraordi-
nary properties.  It ig lighter than water;
its sp. gr. being 0.865 to water 1.0. At com-
mon temperatures, it is solid, soft, and  easi-
ly moulded by the fingers.  At 150° F. it fu-
 ses, and in a heat a little below redness, it
 rises in vapour.   It is perfectly  opaque.
 When  newly  cut, its  colour  is splendent
 whit*, like that of silver, but i t  rapidly tar*
 Irishes in the air.  To preserve  it unchang-
 ed, wo must enclose it in a small phial, with
 pure naphtha.  It conducts electricity  like
 the common  metals.  When  thrown upon
 water, it acts with great violence, and swinw
 upon the  surface, hurning with a beautiful
 light of a  red colour,  mixed  with violet.
 The water becomes a solution of pure pot-
 ash. When moderately heated  in the air, it
 inflames, burns with a red light, and throws
 off alkaline fumes.  Placed  in  chlorine, it
 spontaneously burns with gTeat brilliancy.
   On all fluid bodies which contain wat*-,
 or much oxygen or chlorine, it readily acts;
 and in  its general powers of chemical com-
 bination, says its illustrious discoverer, pot-
 assium may be compared to the alkahest, or
 universal  solvent,  imagined by the alche-
 mists.
   Potassium combines with oxygen, in dif-
 ferent  proportions.  When  potassium  is
 gently heated in common air or in oxygen,
 the result of its combustion  is an orange.
 coloured fusible substance. For every grain
 of the metal consumed, about 1 -fo cubic
 inches of oxygen are condensed.  To make
 the experiment accurately, the metal should
 be burned in a tray of platina covered with
 a coating of fused muriate of potash.
   The substance procured by the combus-
 tion of potassium at alow temperature, was
 first observed in  October 1807, by Sir II.
 Davy, who supposed it to be the protoxide;
 but  MM.   Gay-Lussac  and  Thenard,  in
 1810, showed,  that it  was in reality the
 deutoxide or peroxide.  When it is thrown
 iirto water, oxygen is evolved,  and a solu-
 tion ofthe  protoxide  results, constituting
 common aqueous potash. When itis fused,
 and brought in contact  with combustible
 bodies, they burn vividly, by  the excess of
 its oxygen. If it be heated in carbonic acid,
 oxygen is disengaged, and common subcar-
 bonate of potash is formed.
   When  it is heated very strongly upon
 platina, oxygen  gas  is expelled  from  it,
 and there remains a difficultly fusible  sub-
 stance  of a gray colour, vitreous fracture,
 soluble  in water, without  effervescence,
 but  with  much heat.   Aqueous potash is
 produced.  The above ignited solid, is pro-
 toxide  of potassium,  wbich becomes pure
 potash  by  combination with the equivalent
 quantity of water.  When we produce po-.
 tassium with  ignited iron turnings and pot-
 ash, much hydrogen is disengaged from the
 water of the hydrate, while the iron be-
 comes oxidized from the residuary oxygen.
 By heating together pure hydrate of potash
and boracicacid, Sir H. Davy obtained from
 from 17 to 18 of water, from 1Q0 parts ofthe
solid alkali.
  By acting on potassium with a very small
quantity of water, or by heating potassium 
POT
POT
with fused potash, the  protoxide may also
he obtained.  'The proportion of oxygen in
the protoxide, is determined by the action of
potassium upon water.  8  grains of potas-
sium produce from water about 9£  cubic
inches of hydrogen; and for these the me-
tal  must have fixed 4£ cubic inches of oxy-
gen.  But as 100 cubic inches of oxygen
weigh 33.9 gr. 4J will weigh 1.61.  Thus,
9.61 gr. ofthe protoxide  will contain  8 of
metal; and 100 will contain 83.25  metal 4-
16.75 oxygen. From these data, the prime
of potassium comes out 4.969;  and that of
the protoxide 5.969.  Sir H. Davy  adopts
the number 75 for potassium, corresponding
to 50 on  the oxygen scale.
  When potassium is heated strongly in a
small quantity of common air,  the oxygen
of which is not sufficient for its conversion
into potash,  a substance is formed of a gray-
ish  colour, which, when thrown into water,
effervesces without taking fire.  It is doubt-
ful, whether it be a mixture of the protoxide
and potassium, or a combination of potas-
sium with a simller proportion of oxygen
than exists in the protoxide. In this case, it
would be a suboxide, consisting of 2 primes
of potassium = 10 4- 1 of oxygen = 1.
  When thin pieces of potassium are intro-
duced into chlorine, the inflammation is ve-
ry vivid;  and when potassium is made to act
on chloride of sulphur, there is an explosion,
The attraction of" chlorine for potassium  is
much stronger than the attraction of oxygen
for the metal. Both of the oxides of potas-
sium are immediately decomposed by chlo-
rine, with the formation ofa fixed chloride,
and the extrication of oxygen.
  The combination of potassium and chlo-
rine, is the  substance which has  been im-
properly called muriate of potash, and which,
in common cases, is formed, by causing li-
quid muriatic acid to saturate  solution  of
potash, and  then evaporating the liquid to
dryness and igniting the solid residuum. The
hydrogen of the  acid here unites to the oxy-
gen of the alkali,  forming water,  which  is
exhaled;  while the remaining chlorine and
potassium combine.  It consists of 5 potas-
sium + 4.5  chlorine.
  Potassium  combines with hydrogen, to
form potassuretted hydrogen, a spontaneous-
ly inflammable gas, which comes over occa-
sionally in the production  of potassium  by
the gun-barrel experiment.  MM.  Gay-Lus-
sac and Thenard describe also a solid com-
pound of the same two ingredients, which
they call  a  hydruret of potassium.   It  is
formed by heating the  metal a  long  while
in the gas, at a temperature just under ig-
nition.  They describe it as a grayish solid,
giving out its hydrogen on contact with mer-
cury-
  When potassium and sulphur are heated
together, they combine with  great energy,
with disengagement of heat and light,  even
     VOL. II.
in vacuo.  The resulting sulphuret of pot-
assium is of  a dark gray  colour.  It acts
with great energy on water, producing sul-
phuretted hydrogen, and  burns brilliantly
when heated in the  air, becoming sulphate
of potash.  It consists of 2  sulphur + 5
potassium,  by Sir H. Davy's  experiments.
Potassium has so strong an  attraction for
sulphur, that it rapidly separates it from hy-
drogen.  If the potassium be  heated in the
sulphuretted gas, it takes fire and burns with
great  brilliancy; sulphuret of potassium is
formed, and pure hydrogen is set free.
  Potassium   and  phosphorus  enter into
union  with the evolu ion  of light; but the
mutual action is feebler than in  the preced-
ing compound.  Thephosphuret  of potas-
sium, in its common form,  is a substance of
a dark chocolate colour;  but when heated
with potassium in great excess, it becomes
of a deep  gray ©dour, with considerable
lustre.  Hence, it is probable,  that  phos-
phorus and potassiuin are capable of  com-
bining in two proportions. The  phosphu-
ret of potassium  burns with great brillian-
cy, when exposed to air, and when thrown
into water produces an explosion, in conse-
quence ofthe immediate disengagement of
phosphuretted hydrogen.
  Charcoal which has been strongly heated
in contact with potassium, effervesces in wa-
ter, rendering it alkaline, though the  char-
coal may be  previously exposed to a tem-
perature at which potassium  is volatilized.
Hence, there is probably acompound ofthe
two formed by a feeble attraction.
  Of all known substances, potassium is
that which has the  strongest  attraction for
oxygen; and it produces such a condensa-
tion of it, that the oxides  of  potassium are
denser than the metal itself-   Potassium has
been skilfully used by Sir  H. Davy and MM.
Gay-Lussac and Thenard, for  detecting the
presence of oxygen in bodies.   A number
of substances, indecomposable by other che-
mical agents, are readily decomposed by this
substance.—Elements of Chemical Phil, by Sir
H Davy.
  * Potassium, (Iodide of.)  See Acid (Ht-
DR10D1C.)*
  Pottert.  The art of making pottery is
intimately  connected with chemistry, not
only from the great use  made of earthen
vessels by chemists, but also because all the^
processes of this art, and the means of per-"
feeling it, are dependent on chemistry.
  'The process of manufacturing stoneware,
according to Dr. Watson, is as follows:
  Tobacco pipe  clay from Dorsetshire is
beaten much in water. By this  process, the
finer parts  of the clay remain suspended in
the water,  while the coarser sand and other
impurities fall to the bottom.  The thick li-
quid, consisting of water and the finer parts
of the clay, is farther purified by passing it
through hair and lawn sieves,  of different
                       51 
POT                                   PRE
degrees of fineness. After this, the liquid is
mixed  (in various proportions for  various
wares) with another liquor,  of as nearly as
may be the same density, and consisting  of
flints, calcined, ground, and suspended  in
water.   The mixture is then dried in a kiln;
and being afterward beaten to a proper tem-
per, it  becomes fit for being formed at the
wheel  into dishes, plates, bowls, &c. When
this ware is to be put into the furnace to be
baked, the several pieces of it are placed in
the cases made of clay, called seggars, which
are piled one upon another, in the dome of
the  furnace.  A fire is  then  lighted; and
when the ware is brought to a proper tem-
per, which happens  in about  forty-eight
hours, it is glazed by common  salt.   The
salt is thrown into  the furnace, through
holes in the upper part of it, by the heat of
which it is  instantly converted into a thick
vapour; which, circulating through  the fur-
nace, enters the seggar through holes made
in its side, (the top being covered to  pre-
vent the salt from  falling on the  ware); and
attaching itself to die  surface of the ware, it
forms  that \itreous coat upon the surface
which is,called its glaze.
   The yellow or  queen's-ware is  made of
the same materials as the. Hint-ware; but the
proportion in which the materials are mixed
is not the same, nor is the ware glazed in
the same way.   The  flint-ware is generally
made of four measures of liquid flint, and of
eighteen of liquid clay.  The yellow ware
has a greater proportion of clay in it.   In
some  manufactories  tiicy mix 20, and in
others 24 measures of clay, with 4 of flint.
 These proportions, if est imated by the weight
ofthe materials, would probably give for the
flint-ware about 3 cwt. of clay to 1 cwt. of
flint,and for theyellow ware somewhat more
clay.  The proportion,  however,  for both
sorts of ware depends very much upon the
 nature of the  clay, which is  very  variable
 even in the same pit. Hence a previous trial
 must be made ofthe quality ofthe clay, by
 burning a kiln of the ware.  If there be too
 much fiint mixed witii the clay, the ware,
 when exposed to  the air after burning, is
 apt to crack; and if there be too little, the
 ware will not receive the proper glaze from
 the circulation ofthe salt vapour.
    This glaze, even when it is most perfect,
 is in appearance less beautiful than the glaze
 on the yellow  ware.
    The yellov glaze is made by mixing to-
 gether in water,  till it becomes as thick as
 cream, 112 lb. of white lead, 24 lb. of ground
 flint, and 61b. of ground flint-glass.  Some
 manufactories leave  out the glass,  and mix
 only 80 lb. of white lead with  20  lb.  of
 ground flint;  and others doubtless observe
 different rules, of which it is very difficult
 to obtain an account.
    The ware before it is glazed is  baked in
 the fire. By this means it acquires the pro-
perty of strongly imbibing moisture.  It is
therefore clipped in  the  liquid glaze, and
suddenly  taken  out: the glaze is  nibibed
into its  pores,, and the ware presently be-
comes dry.  It  is  then exposed  :i second
time to  the fire,  by which means the glaze it
has imbibed is melted,and a thin glassy coat
is formed upon its surface.  The  colour of
this coat is more or less yellow, according as
a greater or less proportion of lead has been
used   'The lead is principally instrumental
in producing the glaze, as well as in giving
it the yellow colour; for lead, of all the sub-
stances hitherto known,  has the greatest
power of promoting the vitr ficaton of  the
substances with which  it  is  mixed. The
flint serves  to give a consistence to the K-:td
during  the time  of  its vitrification,  and to
hinder  it from becoming too fluid, and run-
ning down the  sides ofthe ware, and there-
by leaving them unglazed.
   The  yellowish colour which lead  gives
when vitrified with  flints,  may be  wholly
changed  by very small  additions  of other
mineral substances.  Thus, to give one in-
stance,  the beautiful black glaze,  which is
fixed on one sort of the ware made at Not-
tingham, is composed of 21 parts by  weight
of white lead, of five of powdered flints and
of  3  of manganese.  'The queen's-ware at
present is much whiter than formerly.
   'The  coarse stone ware made  at liristol
ensists of  tobacco-pipe clay and  s mil,  and
is glazed by the vapour  of salt,  like Staf-
fordshire flint-ware; but it is fiit inferior to
it in beauty.
   * Potential Cauteht.  Caustic potash.*
   * Potstone,  or Lap is  Ollaris.  Colour
greenish-gray. Massive, and in granular con-
cretions.  Glistening.   Fracture curved fo-
liated.  Translucent on the edges.  Streak
white.  Soft. Sectile. Feels greasy. Some-
what tough. Sp. gr. 2.8.  Its constituents
are, silica 39, magnesia 16, oxide of iron 10,
carbonic acid  20, water 10.  Ii  occurs in
thick beds in primitive  slate.  It is found
 abundantly on  the shores of the lake Como
 in Lombardy.   It is fashioned  into culinary
 vessels in Greenland.  It is a sub-species of
 the rhomboidal mica of Professor Jameson.*
   * Powder of A loo roth.   The white ox-
 ide of antimony, thrown down from the mu-
 riate by water.*
   * Prase.  Colour leek-green.   Massive,
 seldom crystallized.  Its forms are, the six-
 sided prism, and the sixsided pyramid. Lus-
 tre shining.  Fracture conchoidal.  Trans-
 lucent.   Hard.   Tough.   Sp. gr. 2.67.  Its
 constituents are, silica 98.5, alumina, with
 magnesia, 0.5,  and oxide of iron  1.—Bu-
 cholz.  It occurs in  mineral beds  composed
 of magnetic ironstone, galena, &c. It is found
 in the  island of Bute, and in Borrodale.*
   ♦ Prkcipitants.  See Metals, and Misx-
 ral Waters.*
  ' Precipitate, and Precipitation.  When 
PRU    *"'
PRU
a body dissolved in'a fluid is either in whole
or in part made to separate and fall <own  in
the concrete state, this falling down is called
precipitation, md die matte: thus separated
is called  a precipitate.   See Waters (Mi-
nehai.,) and MtTii.s.
   * PRECipiTATF.,/>er se.   Red oxide of mer-
cury, by  heat.*
   ♦Prehnite. Prismatic prehnite; of which
there are two sub-species, the-foliated and
the fibrous.
   1. FoUnted.  Colour apple-green.   Mas-
sive, in distinct concretions, and sometimes
crystallized. The primitive form is an oblique
four-sided prism of 103° and 77°.   The se-
condary  forms are, an oblique four-sided ta-
ble, and  irregular eight-sided table, an irre-
gular six-sided table, and abroad rectangular
four-sided prism.   Shining.   Fracture fine
grained  uneven.  Translucent.    Hardness
from feldspar  to quartz.  Easily frangible.
Sp. gr. 2.8 to  3a».   It  melts with intumes-
cence  into a pale-green or yellow glass. It
does not gelatinize with acids.  Its constitu-
ents are, silica  43.83, alumina 30.33, lime
18.33, oxide of iron 5.66,  water  1.83.—
Kaprotk.  It occurs in France, in  the Alps
of Savoy, and  in the Tyrol.  It is said to
become  electric by  heating.  Beautiful va-
rieties are found in the interior of Southern
Africa.
   2. Fibrous Prehnite.  Colour siskin-green.
 Massive, in distinct concretions, and crystal-
lized in  acicular four-sided prisms.  Glisten-
ing, pearlv.  Translucent. Easily frangible.
 Sp. gr. 2.89.  It melts into a vesicular ena-
 mel.  It becomes electric by heating.   Its
 constituents are, silica  42.5, alumina  28.5,
 lime 20.44, natron and potash 0 75, oxide of
 iron 3, water 2.—Laugier. It occurs in veins
 and cavities  in trap-rocks near Beith in Ayr-
 shire, Bishoptown in Renfrewshire, at Hart-
 field near Paisley, and near Frisky-hall, Old
 Kilpatrick;  in  the   trap-rocks round Edin-
 burgh,  &c*    *             .
   * Prince's Metal.  A species of copper
 alloy, in which the proportion of zinc is more
 considerable than in brass.*
   * Prostate  Concretions.  See Calculi*
   * Prussian  Alkali.   See Acid (Ferro-
 prussic.)*
   * Prussian Blue. See Iron and the above
 Acid."
   * Prussic Acin.   See Acid (Prussic.)*
   * Prussine,  or Prussic Gas, the cyanogen
 of M. Gay-Lussac.   This last term signifies
 the producer of blue.   But the production
  of blue  is never the result of the direct ac-
  tion of this substance on any other single
  body; but an indirect and unexplained ope-
  ration of it in  conjunction with iron, hydro-
  gen and oxygen.   The same reason which
  leads to the term'cyanogen,  would warrant
  us in calling  it leucogen,  erythrogen;  or
  chlorogen;  for it produces white, red, or
  green,  with other, metals, if .t produce blue
with iron.  Although, therefore,  the higa-
es' deference be due to the nom* nclatureof
so distinguished  a chemist as N> Gay-Lus-
sac,  yet I apprehend it is better to retain
the old  word, connected  merely with the
history of the substance.  As cyanogen, like
chlorine and iodine,  by its action on potas-
sium, produces flame, and like them is aci-
dified by hydrogen, I  would  respectfully
propose "the name Prussine.   Its discovery
and  investigation do the highest honour to
to M. Gay-Lussac.
  Prussine, or cyanogen, is obtained by de-
composing the prusside or cyanide of mer-
cury by heat.  But as the prusside of mer-
cury varies in its composition, we shall be-
gin by describing its formation.
  By digesting red oxide  of mercury with
prussian blue and hot water, we obtain a
cvanide perfectly neutral, which crystallizes
in long four-sided prisms, truncated oblique-
ly.   By repeated solutions and crystalliza-
tions, we may free it from a small portion of
adhering iron.   But M. Gay-Lussac prefers
boiling  it with red oxide of mercury, which
completely precipitates the oxide  of iron,
and he  then saturates the  excess of oxide of
mercury, with a little prussic acid,  or a lit-
tle muriatic acid.  The prusside thus form,
ed, is decomposed by heat, to obtain the ra-
dical.   For common experiments,  we may
dispense with these precautions.
   When this cyanide is boiled with red ox-
ide of mercury,  it  dissolves  a considerable
quantity of the oxide, becomes alkaline,
crystallizes no longer in prisms, but in small
scales,  and its solubility in water appears a
little increased.  ' When evaporated to dry-
 ness, it is very easily charred, which obliges
 us to employ the  heat merely of  a water
 bath.   This compound was observed by M.
 Proust. When decomposed by heat, it gives
 abundance of prussine, but mixed with car-
"bonic acid gas.   Proust says,  that  it yields
 ammonia, oil in considerable abundance, car-
 bonic acid, azote, and oxide of carbon.  He
 employed' a moist prusside.  Had  it  been
 dry, the discovery of prussine could hardly
 have escaped him. The prusside of mercu-
 ry, when neutral and quite dry, gives noth-
 ing but prussine; when moist, it furnishes
 ody carbonic  acid, ammonia,  and  a great
 deal of prussic acid vapour.  When we em-
 ploy the prusside made with excess of per-
 oxide,  the same products are obtained, but
 in different proportions,  along with azote,
 and a brown liquid, which Proust took for an
 oil, though it*is not one in reality. Hence to
 obtain  pure prussine,  we must employ the
 neutral prusside in a state  of perfect dryness.
 The other mercurial compound is not, how-
 ever, simply a  sub-prusside.  It is a  com-
 pound of oxide of mercury, and the prusside,
 analogous to the brick coloured precipitate
 obtained by adding a little potash to the so-
 lution of deutochloride of mercury (corrosive 
PRU
PRU
sublimate,) which is a triple compound of
chlorine, oxygen, and mercury,  or a binary
compound of oxide of mercury, with  the
chloride  of that metal.  These  compounds
might be called, oxvprusside  and oxychlo-
ride of mercury.
  When the simple mercurial prusside is
exposed to heat in a small glass retort, or
tube, shut at one extremity, it soon  begins
to blacken.  It  appears to melt like  an  ani-
mal matter,  and then the prussine is disen-
gaged in abundance. This gas is pure from
the beginning  of the process to the  end,
provided always that  the heat be not very
high; for if it  were sufficiently intense to
melt the glass, a little azote would be evolv-
ed.  Mercury is volatilized with a considera-
ble  quantity of prusside, and there remains
a charry matter ofthe colour of soot, and as
light as lampblack.  The prusside of silver
 fives* out likewise prussine when heated;
 ut the mercurial prusside is preferable to
every other.
  Prussine or cyanogen  is a permanently
elastic fluid.  Its smell, which it is impossi-
ble  to describe, is very strong and penetra-
ting.- Its solution in water has a very sharp
taste.  The  gas  burns with a bluish flame
mixed with purple. Its sp. gr., compared to
that of air, is 1.8064.   M. Gay-Lussac ob-
tained it by weighing at the same tempera-
ture, and under the same pressure, a balloon
of about 2^ litres, (152.56 cubic inches,) in
which the vacuum was made to the same de-
gree, and alternately full of air and prussine.
100 cubic inches weigh therefore 55.1295
grains
  Prussine is capable of sustaining a pretty
high heat, without being decomposed.  Wa-
ter, with which  M. Gay-Lussac agitated it,
for some minutes,  at  the temperature of
6Jr>°, absorbed  about 4£ times  its  volume;
Pure alcohol absorbs.23 times its volume.
Sulphuric eti^er and oil of turpentine dis-
solve at least as much as water. Tincturt of
litmus is reddened by prussine. On  heating
the solution the gas  is disengaged, mixed
with a little carbonic acid,  and the blue co-
lour of the litmus is restored.  The carbonic
»cid proceeds no doubt from the decompo-
sition of a small quantity of  prussine and
water. It deprives the red sulphate ofman-
ganese  of its colour, a property which prus-
sic acid does not possess.   This is  a proof
that its elements  have  more mobility  than
those ot the acid. In the dry way,  it sepa-
 rates the carbonic acid from the carbonates.
   Phosphorus,  sulphur,  and iodine may be
•sublimed by the heat  of a spirit-lamp in
 prussine, without occasioning any change on
 it.  Its mixture with hydrogen was not alter-
 ed by the same temperature, or by passing
 electrical sparks through  it.   Copper and
 gold do not combine with it, but iron.-when
 heated almost  to whiteness,  decomposes it
 in part. The metal is covered with a slight
coating of charcoal.andbecomesbrittlc The
undecomposed portion of the gas is mixed
with azote, (contains  free azote.)  In one
trial the azote constituted 0.44 of the mix-
ture, but in general it was less   Platinum,
which had been placed beside the iron, did
not undergo any alteration. Neither its sur-
face nor that of the tube was covered with
charcoal like the iron.
  In the cold, potassium acts but slowly on
prussine, because a crust is formed  on its
surface, which presents an obstacle to the
mutual  action.    On  applying  the spirit-
lamp, the potassium  becomes speedily in-
candescent; the absorption of the gas be-
gins, the inflamed disc gradually diminishes,
and when it disappears entirely, which takes
 filace in  a few seconds,  the absorption  is
 ikewise at an end.  Supposing we employ a
quantity of potassium  that would disengage
50 parts  of  hydrogen from water, we find
that from 48 to 50 parts of gas have disap-
peared.  On  treating the residue with pot-
ash, there usually  remains 4  or 5  parts  of
hydrogen, sometimes 10 or 12.  M.  Gay-
Lussac made a great number of experiments
to discover the origin of this gas.  He thinks
that it is derived from the water which the
prusside  of mercury contains, when  it has
not  been  sufficiently dried.  'Prussic acid
vapour is then produced, which, when de-
composed by the potassium, leaves half  its
volume of hydrogen.   Potassium therefore
absorbs a volume of pure prussine,  equal to
that ofthe hydrogen,  which it woulddisen-
gage from water.
  The compound of prussine and potassium
is yellowish.   It dissolves in water without
effervescence, and the  solution is strongly
alkaline.  Its taste  is the same as that of
hydrocyanate or simple prussiate of potash,
of which it possesses all the properties.
   The gas being very inflammable, M. Gay-
Lussac  exploded it in Volta's eudiometer,
with about 2£ times its volume  of oxygen.
The detonation is very strong; and the flame
is bluish, like that of sulphur burning in oxy-
gen.
   Supposing that we  operate on 100 parts
of prussine,  we find after the explosion a
diminution of volume, which amounts to from
four to nine parts.  When the  residuum is
treated with potash or barytes, it diminishes
from 195 to 200 parts, which  are  carbonic
 acid gas. The new residuum, analyzed over
 water by hydrogen, gives from 94 to 98 parts
 of azote, and the oxygen which it contains,
 added to that in the carbonic acid, is equal
 (within four or five per cent), to that which
 has been employed.
   Neglecting the small differences, which
 prevent these numbers from  having  simple
 ratios to each other, and which,  like  the
 presence of hydrogen, depend upon the pre-
 sence of a variable portion  of  prussic acid
 vapour in the prussine em ployed, proceeding 
PRU                                   PRU
from the water left in the prusside  of mer-
cury, we may admit that prussine  contains
a sufficient quantity of carbon to  produce
twice its volume of carbonic acid gas; that
is to say, two volumes ofthe vapour of car-
bon, and one  volume of azote,  condensed
into a  single volume.  If that supposition
be exact, the density of the radical derived
from it ought to be equal to the density de-
rived from experiment;  but supposing the
density of air to be 1.00, twice that of the
vapour of
    Carbon is      0 8320   (0.8332)
    Azote,         0.9691   (0.9722)
                   1.8011    1.8054
  From the near agreement of these num-
bers with the experimental density, we are
entitled to  conclude that  M. Gay-Lussac's
analysis is correct.  By adding a volume of
hydrogen to a volume of prussine, we ob-
tain two volumes  of prussic acid vapour;
just as by adding  a volume of hydrogen to
a volume of chlorine, we  obtain two vo-
lumes of muriatic acid gas.  The same pro-
portions hold with regard to the vapour of
iodine, hydrogen, and hydriodic acid. Hence
the sp. gr. of these three hydrogen-acids is
exactly equal to half the sum,of the densi-
ties of their respective bases and hydrogen.
This fine analogy  was first estabhshed by
M. Gay-Lussac.
  It is now obvious that the action of potas-
sium on prussine  agrees with  its action on
prussic acid.  We have seen that it absorbs
50 parts of the first, and  likewise that it
absorbs 100 parts of the second, from which
it separates 50 parts of hydrogen.  But 100
parts of prussic acid vapour, minus 50  parts
of hydrogen, amount exactly  to  50  parts
prussine.  Hence the two results agree per-
fectly,  and the two compounds obtained
ought to be identical, which agrees precisely
with experiment.
  'The analysis of prussine being of  great
importance,  M.  Gay-Lussac  attempted  it
likewise by  other methods.   Having put
prusside of mercury into the  bottom of a
glass tube, he covered it with brown oxide
of copper, and then raised the heat to a dull
red.  On heating gradually the part of the
tube containing the prusside, the prussine
was gradually disengaged,and passed through
the oxide,  which it  reduced completely to
the metallic state.   On'washing the gaseous
products with aqueous potash,  at different
parts ofthe process, he obtained only from
0.19 to 0.30 of azote,  instead of 0.33, which
onght  to have remained according to the
preceding  analysis.   Presuming that  some
nitrous compound had been formed, he re-
peated the experiment, covering the oxide
with a column of copper filings, which he
kept at die same temperature  as the oxide.
With this new arrangement, the results were
very singular; for the smallest  quantity of
azote which he obtained during the whole
course  of the experiment  was 32.7 for 100
of gas.  and the greatest was 34.4. The mean
of all the trials was,—
    Azote,           33.6 or nearly 1
    Carbonic acid,    66.4          2
A result which shows clearly that prussine
contains two volumes of the vapour of car-
bon, and one volume of azote.
  In another experiment, instead of passing
the prussine through the oxide of copper, he
made a mixture of one part of  the prusside
of mercury, and 10 parts of the red oxide,
and after introducing it  into a glass'tube,
close at one end, he covered it with  copper
filings, which he raised first to a red heat.
On heating the mixture successively,  the
decomposition went on with the greatest fa-
cility.  The proportions of the gaseous mix-
ture were less regular than-in the preceding
experiment.   Their mean  was,—     *
     Azote,         34.6 instead of 33.3
     Carbonic add,   65.4           66.6
In another experiment he obtained,—
           Azote,          32.2
           Carbonic acid,   67.8
Now the mean of these results gives,—
           Azote,         33  4
           Carbonic acid,   66.6
  No sensible quantity of  water seemed to
be formed during these analyses. This shows
farther, that  what has been called  a prus-
siate of mercury is really a prusside  of that
metal.
  When a  pure solution of potash is intro-
duced  into this gas,  the absorption is rapid.
If the alkali be not too concentrated, and be
not quite saturated, it is scarcely tinged ofa
lemon-yellow  colour.  But if the prussine
be  in  excess, we" obtain a brown solution,
apparently carbonaceous.  On pouring pot-
ash combined with prussine into a saline so-
lution  of a  black oxide of iron, and adding
an  acid, we obtain prussian blue.  It would
appear from this phenomenon that the prus-
sine is decomposed the  instant that it com
bines  with the .potash; but this conclusion
is premature; for when this body is really
decomposed bjf means of an  alkaline solu-
tion, carbonic acid  is always produced, to-
gether with prussic acid and ammonia.  But
on  pouring barytes into a solution of prus-
sine in potash, no  precipitate takes place,
which shows  that no carbonic acid is pre-
sent. On adding an excess of quicklime, no
trace of ammonia is perceptible. Since, then,
no carbonic acid and ammonia have been
formed, water has not been decomposed, and
consequently  no prussic acid evolved. How
then comes the solution of prussine in potash
to produce prussian blue, with  a solution of
iron and  acid!1 The following is M. Gay-
Lussac's ingenious  solution of this  difficul-
ty1-
   The instant an acid  is  poured into  the
solution of prussine in potash, a strong effer- 
PRU
PRU
vescencc of carbonic acid is produced, and
at the same time's strong smell  of prussic
acid becomes  perceptible.  Ammonia is
likewise formed,  which remains combined
with the acid employed, and which may be
rendered very sensible to the smell by the
addition of quicklime.  Since therefore we
are obliged to add an acid in order to form
prussian blue, its formation occasions no far-
ther difficulty.
   Soda, barytes, and strontites produce the
same effect as potash.  We  must therefore
admit that  prussine forms particular combi-
nations with the alkalis, which  are perma-
nent till some circumstance determines the
formation  of new products. These combi-
nations are true salts, which may be regard-
ed as analogous to  those formed by acids.
In fact prussine possesses acid characters.
It contains two elements, azote and carbon,
the first of which  is strongly acidifying, ac-
cording to  M. Gay-Lussac.  (Is  it not as
strongly alkalifying, with hydrogen, in  am-
monia') Prussine reddens the  tincture of
litmus, and neutralizes the bases.  On the
other hand, it acts as a simple body, when it
combines with hydrogen; and it is this dou-
ble function of a simple and compound body
which renders its nomenclature so embarras-
sing-
   Be this as it may, the compounds of prus-
sine and the alkalis, which may be distin-
guished by the term prussides, do not sepa-
rate in water,  like the alkaline chlorurets,
(oxy muriates,) which produce chlorates and
muriates.   But when an acid is added, there
is formed,  1st, Carbonic acid, which corres-
ponds to the chloric acid; 2d, Ammonia and
prussic acid, which correspond to the  mu-
riatic.
   When the prusside  of potash is decom-
posed by an acid, there  is produced a vo-
lume of carbonic acid just equal to that of
the prussine  employed.  What  then  be-
comes ofthe other volume of the vapour of
carbon; for the prussine  contains two,  with
one volume of azote?
   Since there is  produced^ at the expense
ofthe oxygen ofthe water, a volume of car-
 bonic acid, which represents  1  volume of
oxygen, 2 volumes of hydrogen must like-
 wise have been produced.  'Therefore, ne-
 glecting the carbonic acid, there remains
       1 volume  vapour  of carbon^
       1         azote,   •
       2         hydrogen;
 and we must make  these three elements
 combine in totality, so as to produce only
  Jh-ussic acid and ammonia. But the one vo-
  ume of the vapour of carbon, with half a
 volume of azote, and half a volume of hydro-
 gen, produces exactly 1 volume of prussic
 acid, wbile the volume and a half of hydro-
 gen, and the half volume of azote remain-
 ing, produce 1 volume of ammoniacal gas;
 for this substance is formed of 2 volumes of
hydrogen and 1 of azote, condensed into 2
volumes.  See Ammonia.
  A given volume of prussine, then* com-
bined first with an alkali, and then treated
with an acid, produces exactly
    1 volume of carbonic acid gas,
    1           prussic acid vapour,
    1           ammoniacal gas.
  It is very remarkable to see an experi-
ment, apparently very complicated, give so
simple a result.
  The metallic oxides do not seem capable
of producing the same changes on prussine
as the alkalis.  Having precipitated proto-
sulphate of iron by an alkali, so that no free
alkali remained, M. Gay-Lussac caused  the
oxide of iron (mixed necessarily with much
water) to absorb prussine,  and then added
muriatic acid.  But he  did  not obtain  the
slightest trace of prussian  blue; though the
same oxide,  to which he had added a little
potash before adding the acid, produced it
in abundance.^
  From this result one is induced to believe
that oxide.of iron does not combine with
prussine; and so much the more, b«cause wa-
ter  impregnated with this gas never pro-
duces prussian blue with solutions of iron,
unless we begin by adding an alkali.  (See
Prissic Aciu)  The peroxides  of manga-
nese  and mercury,  and the deutoxide of
lead, absorb prussine, but  very slowly.  If
we  add  water,  the combination is  much
more rapid.  With the peroxide of mercu-
ry,  we  obtain a grayish-white compound,
somewhat soluble in water.
  Prussine rapidly decomposes the carbon-
ates at a dull red heat, and prussides of the
oxides are obtained.  When passed through
sulphuret of barytes, it combines without
disengaging the sulphur, and renders it ve-
ry fusible, and of a brownish-black colour.
When put into water, we  obtain  a colour-
less solution, but which gives a deep brown
(maroon) colour to muriate of iron.  What
does not dissolve contains  a good deal of
sulphate, which is doubtless formed during
the preparation of the sulphuret of barytes.
  On dissolving prussine  in the sulphuret-
ted hydrosulphuret  of  barytes,  sulphur is
precipitated, which is again dissolved when
the liquid is saturated with prussine, and we
obtain a solution having a very deep  brovin
maroon colour.  This gas does not decom-
pose sulphuret of silver, or of potash.
   Prussine and sulphuretted hydrogen com-
bine slowly with each other. A yellow sub-
stance is obtained in fine needles, which dis-
solves in water, does not precipitate nitrate
 of  lead, produces no prussian blue,  and is

   § Does not this  experiment justify the
 adoption of the term prussine; since we sec
 that very complicated affinities  must be
 exercised before blue is produced by cya-.
 nogen? 
                PRU

composed of 1  volume  prussine  (cyano-
gen,) and 1$ volume of sulphuretted hy-
dr ogen.§
  Ammoniacal gas and prussine begin to act
on each other whenever they come in con-
tact; but some  hours are requisite to render
the effect complete. We perceive  at first a
white thick vapour, which soon disappears.
The diminution  of volume is considerable,
and the glass in  which the mixture is made,
becomes opaque,  its inside being covered
with a solid brown matter  On mixing 90
parts of prussine,  and 227  ammonia, they
combined nearly in the  proportion of 1 to
1£.  This compound gives  a  dark orange-
brown colour  to water, but dissolves only
in a very small proportion.  The liquid pro-
duces no prussian blue  with  the salts of
iron.
.   When prussic acid is  exposed to the ac-
tion ofa voltaic battery of 20 pairs of plates,
much hydrogen "gas is disengaged at  the
negative pole, while nothing appears at the
positive pole. It is because there is evolved
at that pole, prussine, which remains dissolv-
ed in the acid.  We may,  in  this manner,
attempt the  combination  of metals  with
prussine, placing them at the positive pole.
   It is easy now  to determine what takes
place, when an animal matter is calcined
with potash or its  carbonate. A prusside of
potash is formed.   It has been proved, that
by heat, potash separates the  hydrogen of
the prussic or hydrocyanic acid.  We can-
 not then suppose  that this acid is formed,
while a mixture of potash- and animal mat-
ters is exposed  to a high temperature.  But
wepbtain a prusside of potash, and not of
potassium; for  this last, when.dissolved in
water, gives only prussiate of potash (hydro-
cyanate,) which is decomposed by the acids,
without producing ammonia and carbonic
acid; while the prusside of potash  (cyanide)
dissolves in water, without being altered,
and does not  give ammonia, carbonic acid,
and prussic (hydrocyanic) acid vapour, un-
 less an acid be added. This is the character,
 which  distinguishes a prusside of a metal,
from a prusside of a metalhc oxide.  See
Acid (Prussic)
   The preceding  facts  are taken from M.
 Gay-Lussac's* memoir on hydrocyanic  acid,
presented to  the  Institute, September 18,
 1815, and published in the Annales de»Chi-
mie, voL xcv.
   In the Journal de Pharmacie for Novem-
 ber 1818, M.  Vauquelin has published an
 elaborate dissertation on the same subject,
 of which I have given some extracts  under
 Acid (Prussic. J  I shall insert here his ve-
 ry elegant process for obtaining  pure hy-

   § This is the compound, which Dr. Thom-
 son, from atomic considerations, declares to
 be destitute of hydrogen.
                PRU

drocyanic or prussic acid, from the cyanide
or prusside of mercury.
  Considering that mercury has a strong at-
traction for sulphur, and that prussine unites
easily to hydrogen, when presented in the
proper  state, he thought that sulphuretted
hydrogen might be employed for decompos-
ing dry cyanide (prusside) offnercurv. He
operated in the following  way:—He made
a current of sulphuretted hydrogen gas, dis-
engaged slowly from a mixture of sulphuret
of iron, and very dilute sulphuric acid, pass
slowly through a glass tube slightly heated,.
filled with the mercurial prusside, and com-
municating with a receiver, cooled by a mix-
ture of salt and snow.
   As soon as the   sulphuretted hydrogen
came in contact with the mercurial salt, this
last substance blackened, and this effect gra-
dually extended to the farthest extremity of
the apparatus.  During this time no trace of
sulphuretted hydrpgen could be perceived
at the mouth of a tube proceeding from the
receiver.  As soon as the  odour of this gas
began to be perceived, the process was stop-
ped;  and the tube  was heated in  order  to
drive over the acid which might still remain
in it.  The apparatus being unluted, he found
in the receiver a colourless fluid, which pos-
sessed all the known  properties of prussic ■
acid.  It amounted to nearly the fifth part of
the prusside of mercury employed.
   This process is  easier, and furnishes more
 acid, than M. Gay-Lussac's, by means of mu-
 riatic acid. He repeated it several times, and
 always successfully. It is necessary, merely
 to take care to stop the process, before the
 odour of the sulphuretted  hydrogen begins
 to be perceived; otherwise, the hydrocyanic
 acid will be mixed with it.   However, we
 may avoid this inconvenience, by placing a
 little carbonate of lead at  the extremity of
 the tube.   As absolute hydrocyanic acid is
 required only for  chemical researches, and
 as it cannot be employed in medicine, it may
 be worth while, says M. Vauquelin, to bring
 to the reo .flection of apothecaries, a process '
 of M. Proust, which has, perhaps,  escaped
 their attention. It consists in passing a cur-
 rent of sulphuretted  hydrogen gas through
 a cold saturated solution of prussiate of mer-
 cury in water, till the liquid  contains an ex-
 cess of it; to put the  mixture into  a bottle,
 in order to agitate it from time to time; and
 finally  to filter it.
   If this prussic acid, as almost always hap-
 pens, contain traces of sulphuretted hydro-
 gen, agitate it with a little carbonate of lead,
 and filter it again.  By this process we may
 obtain hydrocyanic acid, in a much greater
 degree of concentration than is necessary for
 medicine.  It has the  advantage  over the
 dry prussic acid,  of being' capable of being
 preserved a long time, always taking care to
 keep it as much as possible from the contact
 of air and heat. Dr. Nimmo's directions for 
PUT                                   PYR
 preparing the prusside of mercury ought to
 be attended to.   His experiments, it will be
 seen, coincide perfectly with the views so ad-
 mirably developed by  M. Gay-Lussac.   See
 Acid (Prussic)
   In the first  volume of the Journal of
 Science and the  Arts, Sir  H. Davy has
 stated some interesting particulars relative
 to prussine. By heating prusside of  mer-
 cury in muriatic acid gas, lie obtained  pure
 liquid prussic acid, and corrosive  sublimate.
 By heating iodine, sulphur, and phosphorus,
 in contact with prusside of mercury,  com-
*pounds of these bodies with prussine or cy-
 anogen may be formed.  That of iodine is
 a very curious body.  It is volatile at a very
 modeifcite heat,  and on cooling,  collects in
 flocculi, adhering  together like oxide of
 zinc formed by combustion.  It has a  pun-
 gent smell, and very acrid taste.*
   * Pulmonary Concretions consist of car-
 bonate of  lime, united to a membranous or
 animal matter.  By Mr. Crompton's analysis,
 Phil. Mug. vol. xiii. 100 parts contain,
     carbonate of lime,             82
     animal matter and water,       18
 Disease proceeding from this cause,  (and I
 believe it to be a frequent prelude and  con-
 comitant of ulcerated lungs,) might be  pro-
 bably benefited  by the regular inhalation of
 aqueous vapour mixed with that of acetic
 acid or vinegar.*
   * Pumice. A mineral of which there are
 three kinds,—the glassy, common, and  por-
 phyrinic.
   1.  Glassy pumice.  Colour  smoke -gray.
 Vesicular.   Glistening, pearly.   Fracture
 promiscuous fibrous. Translucent. Between
 hard and  semi-hard.  Very brittle.  Feels
 rough, sharp, and meagre.  Sp.  gr. 0.378
 to 1.44.  It occurs in beds in the  Lipari Is-
 lands.
   2. Common pumice.   Colour nearly white.
 Vesicular.   Glimmering, pearly.   Fracture
 fibrous.  Translucent on the edges.  Semi-
 hard.  Very brittle.  Meagre  and  rough.
 Sp. gr.  0.752 to 0.914.   It melts  into a
 gray coloured slag.  Its constituents are, si-
 lica 77.5,alumina 17.5, natron and  potash
 3, iron mixed with  manganese 1.75.—Klap-
 roth.  It occurs with the preceding.
   3. Porphyritic pumice.    Colour grayish-
 white.  Massive.  Minutely porous.  Glim-
 mering and pearly.  Sp. gr. 1.661.  It con-
 tains crystals of feldspar, quartz, and mica.
 It  is associated  with claystone,  obsidian,
 pearlstone and pitchstone-porphyry. It oc-
 curs in  Hungary, at Tokay, &c*
   * Putrefaction.  The spontaneous de-
 composition of such animal or  vegetable
 matters, as exhale a fetid smell,  is called
 putrefaction.  The solid and  fluid matters
 are resolved inta gaseous compounds  and
 Vapours which escape, and into  an  earthy
 residuum.  See Adipocere, and Fermenta-
 tion, of whichjrenus, putrefaction is merely
a species. As the grand resolvent of organic
matter is water,  its abstraction by drying,
or fixation  by cold, by salt, sugar, spices,
fkc.  will counteract the  process of putre-
faction.  The atmospheric  air is also ac-
tive  in  putrefaction; hence, its  exclusion
favours the preservation of food; on which
principle, some patents have been obtained.*
  ♦Pwieneite.  Colour grayish-black.  Mas-
sive,  and crystallized  in rhomboid.il dode-
cahedrons. Glistening, and metal-like. Frac-
ture uneven.  Opaque. Hard.  Sp. gr. 2.i!
It melts with intumescence, into a yellowish-
green vesicular enamel. Its constituents are,
silica 4-3, alumina  16. lime 20, oxide of
iron  16, water 4—Vauquelin.   It occurs
in primitive limestone, in the Pic of Eres-
Lids, near Bareges, in the  French  Pyre-
nees*
  * Pyrites.  Native  compounds of metal
with sulphur.   See  the  particular metallic
Ores*
  * PrROfiOM.   A variety of diopside.*
  * Pyrometer.  The most celebrated in-
strument fur measuring high temperatures,
is that invented by the late Mr. Wedgwood,
founded on the principle, that clay progres-
sively contracts  in  its dimensions, as it is
progressively exposed to higher degrees of
heat.   He formed his white  porcelain clay,
into  small  cylindrical  pieces,  in  a mould,
which, when they were baked in a dull red
heat, just fitted into the opening of two brass
bars, fixed to a brass plate,  so as to firm a
tapering space between them.  This space
is graduated; and the farther the pyroimtric
clay gauge can enter, the greater heat does
it indicate.   The two converging rules are
placed at a distance of 0.5 of an inch aj. the
commencement  of  the 6cale, and of 0.3 at
the end.
  Mr. Wedgwood sought to establish a cor-
respondence between the indications of hit
pyrometer, and those ofthe  mercurial ther-
mometer, by employing a heated rod of sil-
ver, whose expansions he measured, as their
connecting link.  The clay-piece and silver
rod were heated in a muffle.*
  When the muffle appeared of a low red
heat, such as was judged  to come fully with-
in the province of his thermometer, it was
drawn forward toward the door of the oven;
and its own door being then nimbly opened
by an assistant, Mr. Wedgwood pushed the
silver piece as far as  it would go.  But as
the division, which  it went to, could not be
distinguished in that ignited state, the muffle
was fifted out, by means of an iron rod pass-
ed through two rings made for that purpose,
with care to keep it steady, and avoid any
shake that might endanger the displacing of
the silver piece.
  When the muffle was grown sufficiently
cold to be examined, he noted the degree of
expansion which the silver piece stood at,
and the degree of heat shown by  the ther- 
PYR                                PYR
mometer pieces measured  in their own
gauge; then returned the  whole into the
oven as before, and repeated the operation
with a stronger  heat, to obtain another
point of correspondence on the two scales.
   The first was at 2£°  of his  thermo-
meter, which  coincided  with 66° of the
intermediate one; and as each of these last
had  been  before  found to contain 20° of
Fahrenheit's,  the 66  will  contain  1320; to
which  add 50,  the degree of his  scale to
which  the (0)  of the  intermediate  ther-
mometer was adjusted, and the sum 1370
will be the degree of Fahrenheit's corres-
ponding to his 2i°.
  The second point of coincidence was at
6-i°  of his, and 92°  of the intermediate;
which 92 being, according to the above pro-
portion, equivalent to 1840 of Fahrenheit,
add  50 as before to  this  number, and his
6}° is found to fall upon the 1890th degree
of Fahrenheit.
  It appears hence that an interval of four
degrees upon Mr. Wedgwood's thermome-
ter is equivalent to an interval of 520° upon
that of Fahrenheit; and, consequently, one
of the former to 130° of the latter; and
that the (0) of Mr. Wedgwood corresponds
to 1077^° of Fahrenheit.
  From these data it  is  easy to  reduce
either  scale to  the  other through  their
whole  range; and from such reduction it
will  appear, that an interval of near 480°
remains between them, which the interme-
diate thermometer serves as a measure for;
that Mr. Wedgwood's  includes an extent
of about 32000 of Fahrenheit's degrees, or
about 54 times as much as that between the
freezing and boiling  points of mercury, by
which  mercurial ones are naturally limited;
that if the scale of Mr. Wedgwood's ther-
mometer  be  produced downward, in the
same manner as Fahrenheit's has been sup-
posed  to be produced upward, for an ideal
standard; the freezing point of water would
fall nearly on 8° below (0) of Mr. Wedg-
wood's, and the freezing point of mercury
a little below 8$°; and that, therefore, of
the extent of now measurable heat,  there
are about 5-10ths of a  degree of his scale
from the freezing of mercury to the freez-
ing of water; 8s from the freezing of water
to full ignition; and 160° above this to the
highest degree he has  hitherto attained.
   Mr. Wedgwood concludes his account
with the  following table of the effects of
heat on different substances, according to
Fahrenheit's thermometer, and his own.
                         Fahr. Wedg-
Extremity of the scale of)  «2-:>770 240°
   his thermometer   ■  )J  "
Greatest  heat  of  his"£ 21877 160
   small air furnace  -  3
Cast iron melts   -  -  -   17977  130
Greatest heat of a com-
   mon smith's forge -
   Vol. U.
Welding heat of iron,") -„. „   Q.
  greatest  -  ...  3
Welding heat of iron,) ^2777   gQ
  least  -----  3
Fine gold melts  -   -  -   5237   32
Fine silver melts -   -  -   4717   28
Swedish copper melts •   4587   27
Brass melts   -  -   -  -   3807   21
Heat by which his  ena-"J
  mel colours are burnt s  1857    6
  on......j
Red heat fully visible in )  -q--    q
  day-light  -  -  - - 3
Red heat fully visible in")   g.»__-
  the dark   -  -  - - 3
Mercury boils  ....  600    3T6oVcr
Water boils.....212    6yVo%
Vital heat.....97    7*fjfo
                                 Q  42
                                 °T0"«"0"
                                 o 389
> 5_9 6
'TO 0 0
17327  125
Water freezes  -  -  -  -    32
Proof spirit freezes  -  -    0
The point at which mer-~\
  cury congeals,  conse- j
  quently the  limit  of)- — 40
  mercurial  tbermome-1
  ters, about          J
  In a scale of heat drawn up  in this
manner,  the comparative extents of the
different departments of  this grand and
universal agent are  rendered conspicuous
at a single glance of the eye.  We see at
once, for instance, how small a portion of
it is concerned in animal and vegetable life,
and in the ordinary operations of nature.
From freezing to  vital heat is barely a five-
hundredth part of the scale; a quantity so
inconsiderable, relatively to the whole, that
in the higher stages of ignition, ten times
as  much might  be added or taken away,
without the Jeast difference being discerni-
ble in any of the  appearances  from which
the  intensity  of  fire  has hitherto  been
judged of.  Hence, at the same time, we
may be convinced ofthe utility and impor-
tance ofa physical measure for these high-
er  degrees of heat, and the utter insuffi-
ciency of the common means  of discrimi-
nating and  estimating  their  force.  Mr.
Wedgwood adds, that he  has often found
differences, astonishing when considered as
a part of this scale, in the  heats of his own
kilns and ovens, without being perceivable
by the workmen at the time, or till the ware
was taken out of  the kiln.
   * Since  dry air  augments in volume,
3-8ths for 180 degrees, and, since its pro-
gressive rate of expansion is probably uni-
form by  uniform increments  of heat, a
pyrometer might easily he constructed on
this principle.  Form a bulb and tube of
platinum, of exactly  the same form as a
thermometer, and connect with the extre-
mity of the stem, at right angles, a  glass
tube of uniform calibre, filled with mercu-
ry, and terminating below in  a recurved
bulb, like that of the Italian barometer. 
PYR
PYR
Graduate the glass tube into a series of
spaces equivalent to 3-8ths of the total vo-
lume of the capacity of the platina bulb,
with 3-4ths of its stem.  The other fourth
may be  supposed to be little influenced by
the source of heat.  On plunging the bulb
and 2-3ds of the stem into a furnace, the
depression  of the mercury will indicate
the degree of heat.  As the movement of
the column will  be very considerable, it
will be scarcely worth while to introduce
any correction for the change of the initial
volume  by  barometric variation.  Or the
instrument might be made, with the recur-
ved bulb sealed, as in Professor Leslie's
differential thermometers.  The glass tube
may be joined by fusion  to the platinum
tube.  Care must be taken to let no mercu-
ry enter the platinum  bulb.  Should there
be  a  mechanical  difficulty in making  a
bulb of this metal, then a hollow cylinder
of $ inch diameter, with a platinum stem,
like that of a tobacco-pipe, screwed into it,
will suit equally well.*
  Pvrophorus.   By this name is denoted
an artificial product, which  takes  fire or
becomes ignited on exposure to the air.
Hence, in the German language, it has ob-
tained the name  of luft-zunder, or  air-tin-
der.   It is prepared from alum by calcina-
tion, with the addition of various  inflam-
mable substances.  Homberg was the first
that obtained it, which he did accidentally
in the year 1680, from a mixture of human
excrement and alum, upon  which he was
operating by fire.
  The preparation is managed in the fol-
lowing manner.  Three parts of alum are
mixed with from two to three parts of ho-
ney, flour, or sugar;  and this mixture is
dried over the fire in a glazed bowl, or an
iron pan, diligently stirring it all the while
with an iron spatula.  At first this mixture
melts, but by degrees it becomes thicker,
swells up, and at last runs into small dry
lumps.  These are triturated  to powder,
and once more roasted over  the fire, till
there is not the least  moisture remaining
in them, and the operator is well assured
that it can liquefy no more: the mass now
looks like a blackish  powder of charcoal.
For  the sake of  avoiding the previous
above-mentioned operation, from  four to
five parts of burned alum may be mixed
directly with two of charcoal powder. This
powder is poured into a phial  or matrass,
with a neck about six inches long.  The
phial, which however must be filled three-
quarters full only, is then put into  a cruci-
ble, the bottom of which is covered with
sand and so much sand is  put round the
former, that the upper part of its body al-
so is covered with it to the height of an
inch; upon this, the crucible, with the phial,
is put into  the  furnace, and surrounded
«itii red-hot .  a!v  The fire,  being now
gradually increased till the phial  becomes
red-hot, is kept up for the space of about
a quarter of an hour, or till a black smoke
ceases to issue from the  mouth of the
phial,  and instead of this  a sulphureous
vapour exhales, which commonly takes fire.
The fire is kept up till the  blue sulphure-
ous flame is no longer to be seen; upon this
the calcination must  be put an end to, and
the phial closed for  a short time with  •
stopper of clay or loam.  But as  soon as
the vessel is become  so cool as to be capa-
ble of being held in the hand, the phial is
taken out of the sand, and the powder con-
tained in it transferred as fast as possible
from the phial, into a dry and  stout glass
made warm, which must  be secured with
a glass stopper.
   We have made a very  good pyrophorua
by simply mixing three parts of alum with
one  of wheat-flour,  calcining them in  a
common phial till the blue  flame  disap-
peared; and have kept it  in the same phial,
well stopped with a  good cork when cold.
   If this powder  be  exposed to the atmos-
phere, the sulphuret  attracts moisture from
the air, and generates sufficient heat to kin-
dle the carbonaceous matter mingled with
it.
   * Pyrope.   A sub-species of dodecahe-
dral garnet.   Colour dark  blood-red, ap-
pearing yellowish by transmitted  light. In
grains. Splendent.  Fracture conchoidal.
Transparent.  Refracts double. Scratches
quartz more readily  than precious garnet.
Sp. gr. 3.718.   Its constituents are,  silica
40, alumina 28.5, magnesia 10, lime 3.5,
oxide of iron 16.5, of manganese,  0.25, ox-
ide of chrome 2,  loss 1.25.—Klaproth.   It
occurs in trap-tuff, at Ely, in Fifeshire; and
in claystone in Cumberland.   At  Zoeblitz,
Saxony, it is  imbedded in  serpentine.  It
is highly valued as a gem in jewellery.*
   • Pyrophysalite.  See Physalite.*
   * Pyrosmalite.   Colour  liver-brown,
inclining to pistachio-green.  In lamellar
concretions, and in regular six-sided prisms,
or the same truncated.  Shining.  Fracture
uneven. Translucent. Semi-hard.  Streak
brownish-white.  Brittle.  Sp. gr. 3.08.  It
is insoluble in water, but soluble in muria-
tic acid with  a small residuum  of silica.
It gives out vapours of chlorine before the
blow-pipe, and becomes  a  magnetic oxide
of iron.  Its constituents are, peroxide  of
 iron 21.81, protoxide of  manganese 21.14,
 submuriate of iron 14.09, silica 35.85, lime
 1.21, water and loss 5.9.—Hisinger.  It oc-
 curs in a bed of magnetic  ironstone, along
 with  calcareous  spar and hornblende, in
 Bjelke's mine in Nordmark,  near  Philip-
 stadt in W ermeland.  It is a very singular
 compound.*
   • Pyrotartauic Acid.   See  Acid
 (Pyrotartaric).*
   '  Pyroxene.  Augite.* 
RAI
RAT
Q
   QUARTATION is an operation by which
    the quantity of one thing is made equal
to a fourth part of the quantity of another
thing.  Thus, when gold alloyed with silver
is to be parted, we are obliged to facilitate
the action of the aquafortis by reducing the
quantity of the former of these metals to
one-fourth part of the whole  mass; which
is done by sufficiently increasing the quan-
tity of the silver, if it be necessary.   This
operation is called quartation, and is pre-
paratory to  the  parting; and even many
authors extend this name to the operation
of parting.   See Assay.
  * Quartz.  Professor Jameson divides
this mineral genus into two species; rhom-
boidal quartz, and indivisible quartz.
  1. Rhomboidal quartz  contains  14 sub-
species. 1. Amethyst. 2. Rock crystal.  3.
Milk quartz. 4. Common quartz. 5. Prase.
6. Cat's Eye.  7. Fibrous quartz.   8. Iron
flint.   9. Hornstone.   10. Flinty slate.  11.
Flint.  12. Calcedony.  13. Heliotrope. 14.
Jasper.
  2. Indivisible  quartz contains  nine sub-
species:  1. Float-stone.   2. Quartz sinter.
3. Hyalite.   4. Opal.   5.  Menilite.  6. Ob-
sidian.  7. Pitchstone.   8. Pearlstone.  9.
Pumice-stone.  We shall treat here of the
quartz sub-species.
  1. Rose, or Milk quartz. Colour rose-red,
and milk-white.  Massive.  Shining. Frac-
ture conchoidal.  Translucent.  It. is pro-
bably silica, coloured with manganese.  It
is found in Bavaria, where it occurs in beds
of quartz in granite, near  Zwiesel, &c.
  2. Common quartz.  Colours, white,  gray,
and many others.  Massive, disseminated,
imitative, in impressed forms, in supposi-
titious and true  crystals.  The latter are, a
six-sided  prism, acuminated  on both ex-
tremities by six planes; a 6'imple six-sided
pyramid, and a double six-sided pyramid.
Splendent to glistening.  Fracture coarse
splintery, and sometimes slaty.  Translu-
cent.  It is one of the most abundant mine-
rals in nature.
  3. Fibrous quartz.  Colours greenish and
yellowish-white.   Massive,  and in  rolled
pieces.   In  curved fibrous concretions.
Glimmering and pearly.  Fracture curved
slaty.  Translucent on the edges   Nearly
as hard  as  quartz.  Not very difficultly
frangible.  Sp. gr. 3.123? It occurs on the
banks of the Moldare in Bohemia.
  4.  Quartz, or  siliceous sinter.  Of this
there are three kinds; the common, opa-
line, and pearly.
  § 1. Common.  Colours grayish-white and
reddish-white.   Massive  and  imitative.
Dull.   Fracture flat conchoidal.  Translu-
cent on the edges.  Semi-hard.  Very brit-
tle.   Sp. gr. 1.81.  Its constituents are, si-
lica 98, alumina 15, iron 0.5.—Klapr.  It
occurs abundantly round the  hot springs
in Iceland.
  § 2. Opaline siliceous sinter.  Colour yel-
lowish-white.  Massive. Fracture conchoi-
dal.   Glimmering.  Translucent  on the
edges.  Semi-hard.  Brittle.  Adheres to
the tongue.   It occurs at the  hot springs
in Iceland.  It resembles opal.
  § 3. Pearl sinter, or fiorite.  Colour milk-
white.  In imitative  shapes.  Lustre be-
tween resinous and pearly.  In thin concen-
tric  lamellar  concretions.   Fracture fine
grained uneven.  Translucent.   Scratches
glass, but not so hard as quartz.  Brittle.
Sp. gr.  1.917.  Its constituents are,  silica
94, alumina  2, lime 4.—Santi.  It has been
found in volcanic tuff and pumice,  in the
Vicentine.  See Rock Crystal.*
  • Quercitron.  See Dyeing.*
  • Quicksilver.   See Mercury.*
R
    RADICAL.   That which is  considered
     as constituting the distinguishing part
of an acid, by its union with the acidifying
principle, or oxygen, which is common to
all acids.  Thus, sulphur is the radical of
the sulphuric and sulphurous acids.  It is
sometimes called the base of the acid, but
base is a term  of more extensive applica-
tion.
  Radical Vinegar.   See Acid (Ace-
tic).
  • Rain.  Mr. Luke Howard, who may
be considered as our most accurate  scien-
tific meteorologist,  is inclined to think,
that rain is in almost every instance the
result of the electrical action of clouds up-
on each other.  This idea is confirmed by
observations made in various  ways, upon
the electrical state of clouds and rain; and
it is very probable that a thunder-storm is
only a more sudden and sensible display of
those energies, which, according to the or-
der observable in the creation in other res-
pects, ought to be incessantly and silently
operating for more general and beneficial
purposes.
  In the formation of the  rain-cloud (nim-
bus), two  circumstances claim particular
attention;  the spreading of the  superior
masses  of  cloud, in all directions, until 
RAl
RA1
they become like the stratus, one uniform
sheet; and the rapid  motion,  and visible
decrease, of the cumulus when brought un-
der the  latter.  The  cirri also,  which so
frequently stretch from the superior sheet
upwards, and resemble  erected hairs, car-
ry much the appearance of temporary con-
ductors for the  electricity,  extricated  by
the sudden union  of  minute  particles of
vapour, into the vastly larger ones that
form the rain.   By one  experiment of Ca-
vallo's,  with a kite carrying 360 feet of
conducting string,  in  an interval between
two showers, and kept up during rain, it
seems that the superior clouds possessed
a positive electricity before the rain, which
on the arrival of a large cumulus, gave place
to a very  strong negative,  continuing as
long as it was  over the kite.   We are not,
however, warranted from this  to conclude
the cumulus which brings  on  rain always
negative, as the same effect might ensue
from a  positive cumulus uniting with a  ne-
gative stratus.  Yet the general  negative
state ofthe lower atmosphere during rain,
and  the  positive   indications  commonly
given by the true stratus,  render this the
more probable opinion.  It is not, however,
absolutely necessary to determine the  se-
veral states of the clouds which appear du-
ring rain, since there is sufficient evidence
in favour of the conclusion,  that clouds
formed  in different  parts  of the atmos-
phere, operate on each other, when brought
near enough, so as to occasion their partial
or entire destruction; an effect which can
be attributed only to their possessing be-
forehand, or acquiring at the moment, the
opposite electricities.
  It may be objected,  says  Mr. Howard,
that this explanation is better suited to the
case of a shower, than to that of continued
rain, for which it does  not seem sufficient.
If it should appear, nevertheless,  that the
supply of each kind  of cloud is  by any
means kept up in proportion  to the con-
sumption, the objection will be answered.
Now, it is a well known fact, that evapora-
tion from the surface of the  earth and wa-
ters,  often returns and  continues during
rain, and consequently  furnishes the lower
clouds while the upper are recruited from
the quantity of vapour brought by the su-
perior current, and continually subsiding
in the form of dew, as is evident both from
the turbidness of the atmosphere in rainy
seasons, and  the  plentiful  deposition of
dew in the nocturnal intervals of rain. Nei-
ther is it pretended that electricity is any
further concerned in the production of rain,
than as a secondary agent, which modifies
the effect of the two  grand predisposing
causes,—a falling temperature, and the in-
flux of vapour.
   Mr. Dalton,  who has  paid much atten-
tion to meteorology, has recently read be-
fore the Manchester Society, an elaborate
and interesting memoir on rain, from which
I shall extract a table, and  some observa-
tions.
Mean Monthly and Jlnnual Quantities of llain at various FlacesJJbein^
                 •Averages for many years, by Mr. Dalton.
the
	03 |»	co5-	-3 Ol ft	o 9			~§	oN CJs.			gs?
	«s £	«« »	<« 0?	<«• <■>		<« ,3	«! §	«! I	*« a	t« cj	3 s % a
	8 »"	3 "»	y	5 a	B 1-	a t>	2 ^	3 §•	si-	33	
	J3	Co ©	C9 ^		co ,r-	S* os	? 8	•• >r	Co *	« s>	? s.
	Inch.	Inch.	Inch.	Inch.	Inch.	Inch.	Inch.	Inch.	Fr. In.	Fr. In.	Inch.
Jan.	2.310	2.177	2.196	3.461	5.299	3.095	1.595	1.464	1.228	2A77	2.530
Feb.	2.568	1.847			5.126	2.837	1.741	1.250	1.232	1.700	2.295
Mar.	2.098	1.523	1.322	1.753	3.151	■2.164	1.184	1.172	1.190	1.927	1.748
April.	2.010	2.104	2.078	2.180	2.986	2.017	0.979	1.279	1.185	2.686	1.950
May.	2.895	2.573	2.118	2,160	3.480	2.568	1.641	1.636	1.767	2.931	2.407
June.	2.502	2.816	2.286	2.512	2.722	2.974	1.343	1.738	1.697	2.562	2.315
July.	3.697	3.66J	3.006	4.140	4.959	3.256	2.303	2.448	1.800	1.882	3.115
Aug.	3.665	3.311	2.435	4.581	5.039	3.199	2.746	1.807	1.900	2.347	3.103
Sept.	3.281	3.654	2.289	3.751	4.874	4.350	1.617	1.842	1.550	4.140	3.155
Oct.	3.922	3.724	3.079	4.151	5.439	4.143	2.297	2.092	1.780	4.741	3.537
Nov.	3.360	3.441	2.634	3.775	4.785	3.174	1.904	2.222	1.720	4.187	3.120
Dec.	3.832 3~6\140	3.288	2.569	3.955 39^714	6.084	3.142	1.981 21.351	1.736 20.686	1.600 181549	2.397 33.977	3.058
		34.118	27.664		53.944	36.919					
  «' Observations on the Theory of Rain.     ration, and contributes to retain the vapour
  "Every one must have noticed an obvi-  when in the atmosphere, and cold precipi-
ous connexion between heat and the vapour  tates or condenses the vapour.  But these
in the atmosphere.  Heat promotes evapo-  facts do not explain the phenomenon of 
RA.N                                RES
 rain, which is as frequently attended with
 an increase as with a  diminution of the
 temperature of the atmosphere.
   "The late Dr. Hutton,  of Edinburgh,
 was, I conceive, the first person who pub-
 lished a correct notion ofthe cause of rain.
 (See Edin. Trans, vol. i. and ii. and Hut-
 ton's Dissertations, &c.) Without deciding
 whether vapour  be simply expanded by
 heat, and diffused through the atmosphere,
 or chemically combined with it, he main-
 tained from the phenomena that the quan-
 tity of vapour capable of entering into the
 air increases in a  greater ratio than the
 temperature; and hence he fairly infers,
 that whenever two  volumes of air of diffe-
 rent temperatures are mixed together, each
 being previously saturated with vapour, a
 precipitation of a portion of vapour must
 ensue, in consequence of the mean tempe-
 rature not being able to support the mean
 quantity of vapour.
   "The cause of rain, therefore,  is now,
 I consider,  no  longer  an object of doubt.
 If two masses of air of unequal tempera-
 tures, by  the  ordinary  currents of the
 winds,  are intermixed, when  saturated
 with vapour,  a precipitation ensues.   If
 the masses are under saturation, then less
 precipitation takes place, or none at all,
 according to the  degree. Also the warmer
 the air, the greater is  the quantity of va-
 pour precipitated  in like circumstances.
 Hence the reason why rains are heavier  in
 summer than winter, and in warm coun-
 tries than in cold.
   "We now inquire into the  cause  why
 less rain falls in the first six months ofthe
 year than in  the last  six months.   The
 whole quantity of water in the atmosphere
 in January is usually about three inches, as
 appears from the dew point, which is then
 about 32°.  Now the force of vapour  at
 that temperature is 0.2  of an inch of mer-
 cury, which is equal to  2.8 or three inches
 of water.   The dew point in July is usual-
 ly about 58° or 59°, corresponding to 0.5
 of an inch of mercury, which  is equal  to
 seven inches of water; the difference  is
 four inches of water, which the atmosphere
 then  contains more than  in  the  former
 month.  Hence, supposing the usual inter-
 mixture of currents of air in both the in-
 tervening periods to be  the same, the rain
 ought to be four inches less in the former
 period of  the year than the average, and
 four inches more in the latter period, ma-
 king a difference  of eight inches between
 the two periods, which nearly accords with
 the preceding observations."*
  Rancidity.   The  change  which oils
 undergo by exposure to the air.
  The rancidity of  oils is probably an ef-
fect analogous to the oxidation of metals.
It essentially depends on the combination
of oxygen with the extractive  principle,
which  is naturally united with  the oily
principle.   This inference is proved by at-
tending to the processes used to  counter-
act or prevent the rancidity of oils.
  Reagent.   In the experiments of che-
mical analysis, the component parts of bo-
dies may either be ascertained in quantity
as well as  quality, by the perfect opera-
tions of the laboratory,  or  their  quality
alone may  be detected by the operations
of certain  bodies called reagents.  Thus
the infusion of galls is  a reagent,  which
detects iron by a dark purple  precipitate;
the prussiate of potash exhibits a blue with
the  same  metal, &c.  See Analysis, and
Waters (Mineral).
  *  Realgar.  Sulphuret of arsenic,  a
native  ore.*
  Receiver.  Receivers are chemical ves-
sels, which are adapted  to the  necks or
beaks of retorts, alembics, and other dis-
tillatory vessels, to  collect, receive, and
contain the products of distillations.
  *  Red Chalk.  A kind  of clay iron-
stone.*
  * Reddle.  Red chalk.*
  REDUCTION,OrREVIVIFICATION.This
word,  in its most extensive sense, is appli-
cable  to all  operations  by which any sub-
stance is restored to its  natural  state,  or
which  is considered  as  such:  but  custom
confines it  to operations  by which metals
are restored  to their metallic state, after
they have been deprived  of this,  either by
combustion, as the metallic oxides, or by
the union of some heterogeneous  matters
which  disguise them, as fulminating gold,
luna cornea, cinnabar, and other compounds
of the same  kind.  'These reductions are
also called revivifications.
  Refrigeratory. See Laboratory.
  Regulus. The name regulus was given
by chemists to  metallic  matters  when se-
parated from other  substances by fusion.
This name was introduced by alchemists,
who, expecting always to find  gold in the
metal collected at the bottom of  their cru-
cibles  after fusion, called this  metal, thus
collected, regulus, as containing gold, the
king of metals.  It was afterwards applied
to the  metal extracted from the ores of the
semi-metals, which formerly bore the name
that is now given to  the semi-metals them-
selves.  Thus we had regulus of antimony,
regulus of arsenic, and regulus of cobalt.
  Resin.  The name resin is  used to de-
note solid  inflammable substances, of ve-
getable origin,  soluble in alcohol,  usually
affording much soot by  their combustion.
They are likewise soluble in  oils,  but not
at all in water;  and are more or less  acted
upon by the alkalis.
  All the resins appear to be nothing else
but volatile oils, rendered concrete by their
combination with oxygen.  The exposure
of these to the  open  air, and the decompo- 
RET                                KHO
 sition of acids applied to tliem, evidently
 prove this conclusion.
   There are some among the known resins
 which are very pure, and perfectly soluble
 in alcohol, such as the  balsam of Mecca
 and of Capivi,  turpentines, tacamahaca,
 elemi: others are less pure,  and contain a
 small portion of extract,  which renders
 them not totally soluble in alcohol; such
 are  mastic, sandarach, guaiacum,  labda-
 num, and dragon's blood.
   What is most generally known by  the
 name of resin, simply, or  sometimes of yel-
 low  resin, is the residuum left after distil-
 ling the essential oil from turpentine.   If
 this  be urged by a stronger fire, a  thick
 balsam, of a dark  reddish  colour, called
 balsam of turpentine, comes over; and  the
 residuum, which is rendered blackish, is
 called black resin, or colophony.
   * Resin, analyzed by  MM.  Gay-Lussac
 and  Thenard, was found  to consist of
   Carbon,  75.944
   Hydrogen, 10.719 } water  15.156
   Oxygen,   13.3373 bydr. in excess 8.9.*
   * Respiration. A  function of animals,
 which consists in the  alternate inhalation
 of a portion of air into an organ called  the
 lungs, and its subsequent exhalation. The
 venous blood, which enters the lungs from
the pulmonary artery, is charged with car-
bon, to which it owes its  dark purple  co-
lour.  When the atmospherical oxygen is
 applied to the interior  of the air vesicles
of the lungs, it combines with the carbon
of the blood, forms  carbonic acid, which
to the amount of from  4.5 to 8 per cent of
the bulk of air inspired, is immediately  ex-
haled.  It does not appear that any oxygen
 or azote is absorbed by the lungs in respi-
ration;  for the volume  of carbonic acid ge-
 nerated is exactly equal to that of the oxy-
 gen which disappears.  Now, we know that
 carbonic acid contains  its own volume of
 oxygen.   It is probable that the quantity
 of carbonic acid, produced  in the  lungs,
 varies in different individuals, and in  the
 same individual under different circum-
 stances.   The change  of the blood,  from
 the purple venous  to the bright red arte
 rial,  seems owing to the  discharge of  the
 carbon.  An ordinary sized  man consumes
 about 46 thousand cubic  inches of oxygen
per diem; equivalent to 125  cubic feet of
 air.  He  makes  about 20 respirations in a
 minute; or breathes twice, for every  seven
 pulsations.  Dr.  Prout and Dr. Fyfe found,
 that after swallowing intoxicating  liquors,
 the quantity of carbonic acid formed in  res-
 piration was diminished.  The same thing
 happens under a course of mercury, nitric
 acid, or vegetable diet.*
   * Retinite.  Retin-asphalt.—Hatchett.
   Colour   yellowish  and  reddish-brown.
 Massive, in angular pieces and thick crusts.
 Surface rough. Glistening, resinous. Frac
ture uneven. Translucent.  Soft.  Brittle.
At first elastic, but becomes rigid by expo-
sure to the air.  Sp. gr. 1.135.  On a hot
iron,  it melts, smokes and burns, with a
fragrant odour. Soluble in potash, and par-
tially in  spirit of wine.  Its constituents
are, resin 55, asphalt  42, earth  3.  It is
found at Bovey Tracey in  Devonshire, ad-
hering to brown coal.*
  Retort.  Retorts are vessels employed
for  many distillations, and most frequently
for  those which require a degree of heat
superior to that of boiling water. This ves-
sel  is a kind of bottle with a long neck, so
bent, that it makes  with the belly of the
retort  an angle  of  about sixty  degrees.
From this form they  have probably been
named retorts.  The most capacious part
of the retort is called its belly.  Its upper
part is called the arch or roof of the re-
tort, and the bent part is the neck.
  • Reusite.  Colour white.  Asamealy
efflorescence, and crystallized, in flat  six-
sided prisms and acicular crystals. Shining.
Fracture conchoidal.   Soft. Its constitu-
ents are, sulphate of soda 66.04,  sulphate
of magnesia 31.35,  muriate of  magnesia
2.19,  and sulphate  of lime 0.42.—Rents.
It is found as an efflorescence on  the sur-
face, in the country round Sedlitz and Said-
schutz.*
  Reverberatory.  See Laboratory.
  Rhodium.   A new metal discovered
among the grains of crude platina by Dr.
Wollaston.  The  mode of obtaining it in
the  state of a triple salt  combined with
muriatic acid and soda, has been given un-
der the article Palladium.  This may be
dissolved in water, and the oxide precipi-
tated from it in a black powder by zinc.
  The oxide exposed to heat continues
black; but with borax it acquires a white
metallic lustre, though it remains infusible.
Sulphur, or arsenic, however,  renders it
fusible, and may afterward be expelled by
continuing the heat.   The button however
is not malleable.  Its  specific  gravity ap-
pears to exceed 11.
  Rhodium unites easily with every metal
that has been tried, except mercurv. With
gold or silver it forms a very malleable al-
loy, not oxidated by a high degree of heat,
but becoming incrusted with a black oxide
when slowly cooled.   One-sixth of it does
not perceptibly  alter the colour of gold,
but renders it much less fusible.  Neither
nitric nor nitro-muriatic acid acts on it in
either of these  alloys;  but  if it be fused
with three parts of bismuth, lead, or  cop-
per, the alloy is entirely soluble in a mix-
ture of nitric acid with two parts of muri-
atic.
  The oxide was soluble in every acid Dr.
Wollaston tried.  The solution in muriatic
acid did not crystallize by evaporation. Its
residuum formed a rose-coloured solution 
ROC                                 RUT
 with alcohol.  Muriate of ammonia and of
 soda, and nitrate of potash, occasioned no
 precipitate in the muriatic solution, but
 formed with the oxide, triple salts, which
 were insoluble in alcohol.  Its solution  in
 nitric acid likewise did not crystallize, but
 silver, copper, and other  metals precipi-
 tated it.
  The solution of the triple salt with mu-
 riate of soda was not  precipitated  by mu-
 riate, carbonate, or hydrosulphuret of am-
 monia, by carbonate  or  ferroprussiate  of
 potash, or by carbonate of soda. The caus-
 tic alkalis however throw down a yellow
 oxide, soluble in excess of alkali; and a so-
 lution of platina occasions in  it a yellow
 precipitate.
  The title of this product to be considered
 as a distinct metal has  been  questioned;
 but the experiments of Dr. Wollaston have
 since been confirmed by Descotils.—Philos.
 Trans.
  * Rhoetizite. Colour white. Massive,
 and  in  radiated concretions.   Glistening
 and  pearly.   Fragments splintery.  Feebly
 translucent on the edges. In other  charac-
 ters, the same as cyanite.  It occurs in pri-
 mitive rocks, with quartz, &c. at  Pfitzsci
 in the Tyrol.*
  •Rhomb Spar.  Colour  grayish-white.
 Massive, disseminated, and crystallized in
 rhomboids, in which  the  obtuse angle  is
 106° 15'. Splendent, between vitreous and
 pearly.   Cleavage threefold oblique angu-
 lar. Fracture imperfect conchoidal.  Harder
 than calcareous spar;  sometimes as hard as
 fluor.  Brittle.  Sp. gr. 2.8 to 3.2.  It ef-
 fervesces feebly with  acids.  Its constitu-
 ents  are, carbonate of lime 56.6, carbonate
 of magnesia 42,  with  a  trace  of iron and
 manganese.—Murray. It occurs imbedded
in chlorite slate,  limestone, &c. It is found
on the banks of  Loch  Lomond; near New-
ton-Stewart in Galloway; in compact dolo-
mite in the Isle of Man and the North  of
England.  It has been  called bitter spar
and muricalcite.*
  Rochelle Salt.  Tartrate of potash
 and soda.  See Acid  (Tartaric).
  "Rock Butter. Colour yellowish-white.
 Massive and tuberose. Glimmering. Frac-
ture  straight foliated.   Translucent on the
edges.  Feels rather greasy. Easily Fran-
 gible.  It is alum mixed with alumina and
oxide of iron.  It oozes out of rocks that
 contain alum. It occurs at the Hurlett alum-
 work, near Paisley.*
  •Rock Cork.   See Asbestus.*
  •Rock Crystal.   Colour white  and
 brown.  In rolled pieces, and crystallized.
The  primitive form is  a rhomboid  of 94°
 15' and 85° 45'.  The secondary forms are,
an equiangular  six-sided  prism,  rather
acutely  acuminated on both  extremities
by six planes, which are set on the lateral
planes;  a double  six-sided  pyramid; an
acute simple six-sided pyramid;  an acute
double  three-sided pyramid.  Splendent.
Fracture perfect conchoidal.   Transparent
or translucent.  Refracts  double,  feebly.
Scratches feldspar. Rather easily  frangi-
ble.  Sp. gr. 2.6 to  2.88.  When two pieces
are rubbed against each  other, they be-
come phosphorescent, and exhale an  elec-
tric odour.  Its constituents are, silica 99
3-8ths, and a trace of ferruginous alumina.
—Bucholz. Some  chemists maintain, that
it has  one or two per cent  of moisture.
Crystals of great size and beauty  are found
in Arran, in drusy  cavities in  granite; but
the finest are found in the neighbourhood
of Cairngorm in Aberdeenshire, where they
occur in granite, or in alluvial soil, along
with beryl and topaz; and in the secondary
greenstone of Burntisland in Fifeshire. The
most magnificent groups of crystals come
from Dauphiny.
  The varieties  inclosing  crystals of tita-
nium, the Venus hair-stones  of  amateurs,
and  those containing  actynolite,  or the
Thetis hair-stones,  are in much repute, and
sell at a considerable price.—Jameson.*
   * Rock Salt.  Hexahedral rock salt.
   1. Foliated.   Colours white and  gray.
Massive, disseminated, and crystallized in
cubes.   Splendent  and resinous.  Cleavage
threefold rectangular.   Fracture conchoi-
dal.  Fragments cubic.  Translucent. As
hard as gypsum.   Feels rather  greasy.
Brittle.   It has a saline taste.  Sp. gr. 2.1
to 2.2.
  2. Fibrous.  Colour white.  Massive, and
in fibrous concretions.  Glistening, resin-
ous.  Fragments  splintery.   Translucent.
It decrepitates when heated.   The consti-
tuents of Cheshire  rock salt, in 1000 parts,
are,  muriate of soda  983£,  sulphate of
lime 6£, muriate of magnesia 0.-/^-, muri-
ate of  lime O-iV, insoluble matter  10.—
Henry.
  The greatest formation of rock salt is in
the muriatiferous clay.  The salt is  occa-
sionally associated with thin  layers of an-
hydrite, stinkstone, limestone, and sand-
stone.   The  principal deposite in Great
Britain is in Cheshire.  The beds alternate
with clay and marl, which contains gyp-
sum. It occurs also at Droitwich, in Wor-
cestershire.  For other localities, see Pro-
fessor Jameson's Mineralogy,  iii. 6.*
  * Rock Wood.  See Asbestus.*
  * Roestone.  See Limestone.*
  * Rose Quartz.  See Quartz.*
  * Rubellite.  Red tourmalin.*
  * Ruby.  See Sapphire.*
  * Ruby-spinel.  See Spinel.*
  * Rust. Red oxide of iron.*
  • Rutile.  An  ore of titanium.* 
SAL
s
SAT,
* OACLACTATES.    See Acid (Sac
  O  lactic).*
  * Safflower.  See Carthamus.*
  * Sagenite.  Acicular Rutile.*
  •Sahlite.   Colours   greenish-gray,
and  green of other shades.  Massive,  in
straight lamellar concretions,  and crystal-
lized; in a  broad  rectangular four-sided
prism, approaching the tabular  form,  or
truncated on the lateral edges. Splendent
on the principal fracture; on the cross frac-
ture, dull.  Cleavage fivefold.  Fracture,
uneven. Translucent on the edges. Harder
than augite.  Rather brittle.  Sp.  gr. 3.22
to 3.47.   It melts with great difficulty.  Its
constituents are, silica  53, magnesia  19,
alumina 3, lime 20, iron and manganese 4.
— Vauquelin.  It  occurs  in  the Island  of
Unst in Shetland; in granular limestone  in
the Island of Tiree; and in Glentilt.   It is
a sub-species of  oblique edged augite.*
  Sal Alembroth.  A compound muri-
ate of mercury and ammonia.   See Alem-
broth.
  *  Sal Ammoniac (Native);  of which
there are two kinds, the volcanic and con-
choidal.
  1.  Volcanic.  Colour yellowish and  gray-
ish-white.   In   efflorescences,  imitative
shapes, and crystallized; in an octohedron;
rectangular  four-sided prism, acuminated
with four planes, set on the lateral planes;
a cube truncated on the  edges; a  rhomboi-
dal dodecahedron, and a double eight-sided
pyramid,  acuminated with  four planes.
Shining.   Cleavage in the direction of the
planes of the octohedron.   From  transpa-
rent to opaque.  Harder than talc. Ductile
and elastic.  Sp. gr. 1.5 to 1.6.  Taste sharp
and  urinous.  When  rubbed with quick-
lime, it exhales ammonia.  Its constituents
are,  sal ammoniac 99.5, muriate of soda
0.5.—Klaproth.  It occurs in the vicinity of
burning beds of coal, both  in Scotland and
England.  It is met with at Solfaterra, Ve-
suvius, iEtna, &c.
  2. Conchoidal. It occurs in angular pieces,
and consists of, sal ammoniac 97.5, sulphate
of ammonia 2.5.—Klaproth.  It is said to
occur, along with sulphur,  in beds of indu-
rated clay or clay-slate, in  the country of
Bucharia.—Jameson.   See Acid  (Muri-
atic),
  Sal Ammoniac.  Muriate of ammonia.
  Sal Ammoniac (Secret).  Sulphate
of ammonia, so  called  by its discoverer
Glauber.
  Sal Catharticus Amarus. Sulphate
of magnesia.
  Sal de Duobus.   Sulphate of potash.
  Sal Diureticus.   Acetate of potash.
  Sal Gem.  Native muriate of soda.
  Sal Glauberi.  Sulphate of soda-
  Sal Mart is.  Green sulphate of iron.
  Sal Mirabile,  or  Sal  Mirabile
Glauberi. Sulphate of soda.
  Sal Mirabile  Perlatum, or  Sal
Perlatum-   Phosphate of soda.
  Sal Polychrest Glaseri.  Sulphate
of potash.
  Sal Prunella.  Nitrate of potash, cast
into flat cakes or round balls, after fusion.
  * Salifiable Bases, are the  alkalis,
and those earths and metallic oxides, which
have the power of neutrali zing acidity, en-
tirely or in part, and producing salts.*
  Saliva.  The fluid secreted  in the
mouth, which  flows in considerable quan-
tity during a repast, is known by the name
of saliva.
  Saliva,  beside water, which constitutes
at least four-fifths of its bulk, contains the
following ingredients:—
      1.  Mucilage,
      2.  Albumen,
      3.  Muriate of soda,
      4.  Phosphate of  soda,
      5.  Phosphate of lime,
      6.  Phosphate of  ammonia.
But it cannot be doubted, that, like all the
other animal  fluids, it is liable to  many
changes  from   disease.  &c.  Brugnatelli
found the saliva of a patient labouring un-
der an obstinate venereal disease impreg-
nated with oxalic acid.
  The concretions which sometimes  form
in the salivary  ducts, &c. and the tartar or
bony crust, which so often  attaches itself
to the teeth,  are composed of phosphate
of lime.
  Salmiac. A word sometimes used for
sal ammoniac.
  * Salt.  This term has been usually
employed to denote  a compound, in definite
proportions, of acid matter, with an alkali,
earth, or metallic oxide.  When the pro-
portions  of the constituents are so adjust-
ed, that  the resulting  substance does not
affect the colour of infusion of litmus, or
red cabbage, it is then called a neutral salt.
When the predominance of acid is evinced
by the reddening of these infusions, the salt
is said to be acidulous, and the prefix super,
or bi, is used to indicate this excess of acid.
If, on the contrary, the acid matter appears
to be in defect, or short of the quantity
necessary for neutralizing the alkalinity of
the base, the salt is then said to be with
excess of base, and the prefix sub is attach-
ed to its  name.
   The discoveries of Sir H. Davy have how-
ever taught us to modify our opinions con-
cerning saline  constitution.   Many bodies,
such as culinary salt, and muriate of  lime. 
SAL                                  SAL
to which the appellation of salt cannot be
refused,  have not been proved to contain
either acid or alkaline matter; but must,
according to the strict logic of chemistry,
be regarded as compounds of chlorine with
metals.
  That great chemist remarks, that very
few of the substances which have been al-
ways  considered as  neutral salts, really
contain, in their dry state, the acids and
alkalis from which they were formed.  Ac-
cording to his views, the muriates and flu-
ates must be admitted to contain  neither
acids,  nor  alkaline  bases.  Most of the
prussiates (or prussides) are shown by M.
Gay-Lussac to be in the same case.  Nitric
and sulphuric acids  cannot be procured
from the  nitrates and sulphates without the
intervention  of  bodies containing hydro-
gen; and if nitrate of ammonia were to be
judged of from the results of its decompo-
sition, it  must be regarded as a compound
of water and nitrous oxide. To this posi-
tion it might perhaps be objected, that dry
sulphate  of iron yields sulphuric acid by
ignition in  a retort,  while oxide of iron re-
mains.  Only those acids,  says he, which
are compounds of oxygen and inflammable
bases, appear to enter  into combination
with the  fixed alkalis and alkaline  earths
without alteration;  and it is impossible to
define the  nature  of the arrangement of
the elements in  their neutral  compounds.
The phosphate and carbonate of lime have
much  less  of the characters attributed to
neutrosaline bodies  than chloride of calci-
um (muriate of lime), and yet this last bo-
dy is  not known  to  contain either  acid or
alkaline matter.  M. Gay-Lussac supposes,
that a chloric acid, without water or hydro-
gen, of one prime  proportion of chlorine,
and five of oxygen, exists in all the hyper-
oxymuriates  (chlorates), but he does  not
support his proposition by any proof.  The
hyperoxymuriates were shown by Sir H.
Davy, in  1811, to be composed of one prime
of chlorine, one  of  a basis, and sis of oxy-
gen.  Now hydrogen, in the liquid chloric
acid of M. Gay-Lussac, may be considered
as acting the part of a base; and to be ex-
changed  for potassium in the salt hypo-
thetically called  chlorate of potash.  It is
an important circumstance in the law of
definite proportions, that when one metal-
lic or inflammable basis (potassium or hy-
drogen, for example), combines with cer-
tain proportions of a compound as hexoxy-
genated  chlorine, all the  others  combine
with the  same proportions.
  M.  Gay-Lussac states, that if the chloric
acid be not admitted as a pure combina-
tion of chlorine  and oxygen,  neither can
the hydronitric or hydrosulphuric acids be
admitted as pure combinations of oxygen.
This  is perfectly obvious.   An acid, com-
   Vol.  11.
posed of  five proportions of oxygen ant)
one of nitrogen, is altogether hypothetical;
and it is a simple statement of facts to say,
that liquid nitric acid is a compound of one
prime equivalent of hydrogen, one of azote,
and six of oxygen.  (Such acid has a sp.
gr. considerably greater than 1.50).  The
only difference  therefore,  between nitre
and hyperoxymuriate of potash, is, that
one contains  a  prime of azote, and the
other a prime of chlorine.—Thus,
   Nitrate of potash.   Chlorate of potash.
  1 prime azote,      1 nrime chlorine,
  6 primes oxygen,   6 primes oxygen,
  1 prime potassium.  1 prime potassium.
In each, substitute hydrogen for its kin-
dred combustible, potassium, and you have
the liquid acids.
   The chloriodic acid, the chlorocarbonous,
and the binary acids, containing hydrogen,
as muriatic and hydriodic, combine with
ammonia without decomposition, but they
appear  to be decomposed in acting upon
the fixed  alkalis, or  alkaline  earths;  and
yet the solid substances they form, have
all the characters which were formerly re-
garded as peculiar to neutral salts, consist-
ing of acids and alkalis, though they none
of them contain the acid, and only the two
first of the series contain the alkalis from
which they are  formed.   The preceding
views of saline constitution, seem to be per-
fectly  clear and satisfactory; and place in
a conspicuous light,  the paramount logic
of the English chemist.
   The solubility of salts in water, is their
most important general habitude.  In this
menstruum they are usually crystallized;
and by its agency they are purified and se-
parated from one another, in the inverse
order of their solubility. The most exten-
sive series of experiments on the solubility
of salts, which has been published, is that
of Hassenfratz, contained in the 27th, 28th,
and 31st volumes ofthe Annates  de Chimie.
Dr. Thomson has copied them into the 3d
volume of his System; and I should also
have willingly followed the example, were
I not aware from my own researches, that
several of Hassenfratz's results are errone-
ous.  It is four years since I commenced a
very extensive train of experiments on this
subject, so important to the practical che-
mist,  but unforeseen  obstructions  have
hitherto prevented their completion. Many
of Hassenfratz's determinations, however,
are very nearly correct. But his  statement
of the relation between  the density  of
slaked lime, and the proportion of its com-
bined water, is  so  absurd, that I wonder
that a person of his reputation should have
published it, and that Dr. Thomson should
have embodied it in his System.  In  one
experiment,  10000 grains of lime, sp.  gr.
                      33 
SAL                                  SAL
 1.5949, combined with 1620 of water, give
 a hydrate of sp. gr. 1.4877; and, in another,
 10000 grains of lime, sp. gr. 1.3175, com-
 bined with 1875 of water, form  a hydrate
 of sp. gr. 0.972.  Four parts of lime, sp.
 gr. 1.4558, combined with 1 of water, are
 stated to yield a hydrate of sp.  gr.  1.400;
 and  with 2  of water, of specific gravity
 0.8983!  Now, the last proportion forms a
 mass greatly denser than water, instead of
 being much lighter than proof spirits.
  " Mr. Kirwan has pointed out," says Dr
 Thomson, " a very ingenious method of es-
 timating the saline contents of  a mineral
 water whose specific  gravity is known; so
 that the error does not exceed one or  two
 parts in the hundred.  The method is this:
 —subtract the specific gravity of pure wa-
 ter from the specific gravity of the mineral
 water examined (both expressed in whole
 numbers), and multiply the remainder by
 1.4.  The product is the saline contents, in
 a quantity of the water,  denoted by  the
 number employed to indicate the specific
 gravity of distilled water.  Thus, let the
 water be of the specific gravity of 1.079,
 or in whole numbers 1079.  Then the spe-
 cific gravity of distilled water will be 1000.
 And 1079 — 1000 x  1-4 = 110.6 = saline
contents in 1000  parts of the  water in
question; and, consequently, 11.06 (errone-
 ously printed 110.6),  in 100 parts of the
 same water."   Divested of its superfluous
 tautology, this rule is; multiply by 140 the
 decimal part of the number, representing
the sp. gr. of the saline solution, and  the
product  is  the dry  salt  in 100 grains.
 "This formula," adds the Doctor, "will
 often be of considerable use, as it serves
 as a  kind  of standard to  which we' may
 compare our analysis." System, vol. iii. p.
 231.
  In the article Caloric of this Diction-
 ary,  the reader will find the following pas-
 sage:—" I did not so far violate  the  rules
 of philosophy, as to make  a general  infe-
 rence from a particular case, a practice, it
must be confessed, too common with some
 chemical writers."   The present instance
 is very instructive.  For Mr. Kirwan, the
original author of this formula, I entertain
the highest esteem.  He devoted himself,
with distinguished zeal, candour, and suc-
 cess, to the  cultivation of  chemistry,  and
when he wrote, an empirical rule like  the
preceding was  a  very pardonable error.
But, at the present day, it is ridiculous to
hold it forth as a kind of standard.  With
 solutions of nitre and common salt, it gives
tolerable approximations; and hence, I fan-
cy that from these solutions the rule must
have been framed.  But for solution of sul-
 phate of soda, this kind of standard gives a
 quantity of dry salt nearly double, and for
 that  of sal ammoniac, less  than one-half 'the
 real  quantity present.
  M. Gay-Lussac has recently published in
the Ann.  de Chimic et Phys. xi. 296,  an
important memoir on the solubility of salts,
from which I shall make a few extracts.
  One is astonished, says this excellent che-
mist, on  perusing the  different  chemical
works, at the inaccuracy of our knowledge
respecting the solubility of the salts. They
satisfy themselves with  the common obser-
vation,  that the salts are more soluble  in
hot than in cold water, and with the solubi-
lity of a few of them at  a temperature usu-
ally very uncertain; 'yet it is upon this pro-
perty of salts that their  mutual decomposi-
tion, their separation, and  the different pro-
cesses for analyzing them depend.  As a
chemical process, the solution of the salts
deserves peculiar attention; for though the
causes to which it is due are the same  as
those which produce other combinations,
yet their  effects are not similar.  It is  to
be wished that this  interesting part of che-
mistry,  after remaining so long  in vague
generalities, may at last enter the domain
of experiment; and that the solubility  of
each body may be determined, not merely
for a fixed temperature,  but for variable
temperatures. In the natural sciences, and
especially  in  chemistry,  general conclu-
sions  ought to be the  result of a minute
knowledge of particular facts, and should
not precede  that knowledge.  It is only
after having acquired this knowledge, that
we can be sure of the existence of a com-
mon type, and that we can venture to state
facts in  a general manner.
  The determination of  the quantity of salt
which water can dissolve is not a very diffi-
cult process.  It consists in saturating the
water exactly with the salt whose solubility
we wish to know at a determinate tempera-
ture, to  weigh out a certain quantity of that
solution, to evaporate it, and weigh the sa-
line residue.  However, the  saturation  of
water may present considerable uncertain-
ty, and before going further, it is proper  to
examine the subject.
  We obtain a  perfectly  saturated  saline
solution in the  two following ways. By
healing the water with the salt, and allow-
ing it to  cool  to the temperature whose
solubility is wanted; or by putting into cold
water a great excess of  salt, and gradually
elevating the temperature.  In each case,
it is requisite to keep the final temperature
constant for two hours at  least, and to stir
the saline solution frequently, to be quite
sure of its perfect  saturation.  By direct
experiments  made  with  much  care, M.
Gay-Lussac ascertained  that these two pro-
cesses give the very same result, and that
of consequence they may  be employed in-
differently.
  Yet Dr. Thomson says, he found that
water retains more  oxide  of arsenic when
saturated by cooling, than when put in con- 
SAL
SAL
 tact with the oxide without any elevation
 of temperature; but the reason I am per-
 suaded was that he employed too little ox-
 ide of arsenic relatively to the water, and
 that he did not  prolong the contact suffi-
 ciently   We perceive in fact, on a little
 reflection, that saturation follows in its pro-
 gress a decreasing  geometrical  progres-
 sion, and that  the time necessary for com-
 pleting it depends upon the surface of con-
 tact of the solvent and the body to be dis-
 solved.
   It happens often that the solution  of a
 salt which does not crystallize, and which,
 for  that reason,  we consider as saturated,
 yields saline  molecules to the crystals of
 the same nature plunged into it; and it has
 been concluded from this, that the crystals
 of a salt impoverish a solution, and make
 it sink below its true point of saturation.
 The fact is certain; it is even very general;
 but I am of opinion that it has been ill ex-
 plained.
   Saturation  in  a saline solution of an in-
 variable temperature, is the point at which
 the solvent, always in contact with the  salt,
 can neither take up any more, nor let go
 any more. This point is the only one which
 should be adopted, because it  is determin-
 ed by chemical forces, and because it re-
 mains constant as long as these forces re-
 main constant. According to this definition,
 every saline solution which can let go salt
 without any change of temperature is of
 necessity supersaturated. It may be shown
 that, in general, supersaturation is not  a
 fixed, point, and  that the cause which  pro-
 duces it,  is the  same as that which keeps
 water  liquid  below  the  temperature at
 whioh it congeals.
   " I shall now give an account of the ex-
 periments which I  have made  on the solu-
 bility of the salts.
   " Having saturated water with a salt at
 a  determinate temperature, as I have  ex-
 plained above, I  take a matrass capable of
 holding 150 to 200 grammes of water, and
 whose neck is  15  to 18 centimetres in
 length. After having weighed  it empty, it
 is  filled to about  a fourth part  with the sa-
 line  solution, and weighed again.  To eva-
 porate the water, the matrass  is laid hold
 of by the neck by a pair of pincers, and it
 is  kept on a  red-hot iron at  an angle of
 about 45°,  taking care to move it continu-
 ally, and to give  the liquid a rotatory mo-
 tion, in order to favour the boiling, and to
prevent the violent bubbling up which is
very common with some saline solutions, as
soon as,  in consequence  of evaporation,
they begin to deposite crystals. When the
saline mass is dry, and when no  more aque-
ous vapours are driven off at a  heat nearly
raised to redness, I blow into the matrass
by means of a glass tube fitted to the noz-
zle of a pair of bellows* in order to drive-
out the aqueous vapour which fills it. The
matrass is then allowed to cool, and weigh-
ed.  I now know the  proportion of  water
to the salt held in solution,  and this  is ex-
pressed  by representing the quantity  of
water to be  100.  Each of the following
results is the mean of at least two experi-
ments:—

   Solubility of Chloride of Potassium.
Temperature tentigrade. 0.00°	Chloride dissolved by 100 water. 29.21
19.35	34.53
52.39	43.59
79.58	50.93
109.60	59.26
Solubility of Chloride of Barium.	
Temperature centigrade. 15.64"	Salt dissolved in 100 water. 34.86
49.31	43.84
74.89	50.94
105.48	59.58"
  In these experiments, the chloride of ba-
rium is supposed to be anhydrous; but as
when it is crystallized it retains two  pro-
portions of water,  22.65, for one of chlo-
ride, 131.1, we must of necessity, in order
to compare its solubility with that of other
salts, increase each number of solubility
by the same  number multiplied into the
ratio of 22.65 to 131.1, and diminish by as
much the quantity of water.  On making
this correction, the preceding results  will
be changed into the following:—
Temperature.
   15.64*
   49.31
   74.89
  105.48
Salt diss, in 100 water.
        43.50
        55.63
        65.51
        77.89
Solubility of Chloride of Sodium.
Temperature.
   13.89°
   16.90
   59.93
  109.73
Salt diss, in 100 water.
        35.81
        35.88
        37.14
        40.38
Solubility of Sulphate  of Potash.
Temperature.    Salt diss, in 100 water.
 12.72°
 49.08
 63.90
101.50
10.57
16.91
19.29
26.33
Solubility of Sulphate of Magnesia.
 Temperature.    Salt diss, in 100 water,
14.58*
39.86
49.08
64.35
97-03
32.76
45.05
49.18
56.75
72. ~>0 
SAL
SAL
  The sulphate of magnesia is here sup-
posed anhydrous; but as it crystallizes re-
taining seven portions of water,  79.3, for
one proportion of salt, 74.6, each number
which expresses the solubility, must be in-
creased by this number  multiplied by the
ratio of 79.3 to 74.6, and the corresponding
quantity of water diminished as much. We
shall  thus have for the solubility of  crys-
tallized sulphate of magnesia the following
results:—
      Solubility of Nitre.
Temperature.    Salt diss, in 100 water.
Temperature,
   14.58°
   39.86
   49.08
   64.35
   97.03
103.69
178.34
212.61
295.13
644.44
  These results are no longer proportional
to the temperatures; they  augment  in  a
much greater ratio.
Solubility of Sulphate		of Soda.
	Salt soluble	n 100 water.
Temperature.	Anhydrous.	Crystallized.
0.00°	5.02	12.17
11.67	10.12	26.38
13.30	11.74	31.33
17.91	16.73	48.28
25.05	28.11	99.48
28.76	37.35	161.53
30.75	43.05	215.77
31.84	47.37	270.22
32.73	50.65	322.12
33.88	50.04	312.11
40.15	48.78	291.44
45.04	47.81	276.91
50.40	46.82	262.35
59.79	45.42	--
70.61	44.35	--
84.42	42.96	--
103.17	42.65	--
 0.00«
 5.01
11.67
17.91
24.94
35.13
45.10
54.72
65.45
79.72
97.66
13.32
16.72
22.23
29.31
38.40
54.82
74.66
97.05
125.42
169.27
236.45
  We see by these results, that the solubi-
lity of sulphate of soda follows a very sin-
gular law. After having increased rapidly
to about the temperature of 33°, where it is
at its maximum, it diminishes to 103.17°,
and at that point it is nearly the  same as
at  30.5.°   The sulphate  of soda  presents
the second example of a body whose solu-
bility diminishes as the  temperature aug-
ments; for Mr. Dalton has already observed
the same property in lime.

     Solubility of Nitrate of Barytes.
     Temperature.   Salt diss, in 100 water.
  0.00°
 14.95
 17.62
 37.87
 49.22
 52.11
 73.75
 86.21
191.65
 5.00
 8.18
 8.54
13.67
17.07
17.97
25.01
29.57
35.18
    Solubility of Chlorate of Potash.
   Temperature.
        0.00°                3.33
       13.32                 5.60
       15.37                 6.03
       24.43                 8.44
       35.02                12.05
       49.08                18.96
       74.89                35.40
       104.78                60.24

  Plate VIII. exhibits a perpendicular sec-
tion through the middle of the  salt mine
of Visachna, on the south-west ofthe Car-
pathian mountains.
  1. A stratum of vegetable mould.
  2. Stiff yellow clay.
  3. Gray and yellow clay, mixed with spots
and veins of sand and ochre.
  4. Grayish-blue clay.
  5. Fine white sand.
  6. Black, fat, bituminous clay, immedi-
ately  covering the bed of salt.
  7. The body of salt, divided into inclined
strata.   This has been  penetrated to the
depth of about two  hundred yards.  It is
traversed by veins (8, 8,) of a bituminous
clay,  of the same nature as that at 6.  This
clay contains  sulphate of lime.
   A. The shaft by which the salt is drawn
up.
   C.  The  shaft through which  the  work-
 men  pass up and down by means ofa ladder
 placed in it.
   D. A shaft that receives the rain-water,
 and conducts it to the dram F.
   B. A shaft that receives rain-water, and
 conducts it into the gallery E.
   E, E, F. Sections of two circular galleries
 surrounding the shafts A and C, which col-
 lect  the waters that penetrate between the
 strata of clay, and conduct them to  the
 drain F, through which they are carried off.
    H, H. A conical space hollowed  out of
 the  rock salt in working it.
    a, a, a, a. Pieces of timber driven into the
  bed of salt, and supporting all the wood-
  work of the shafts.
    b, b, b, b. Sheep-skins, nailed  on these
  pieces of timber, to keep them from wet.
    c, c. Bags in which the salt is drawn up.
    d, d, d. Cuts for extracting  the salts in
  oblong squares. 
SAL
SAL
  e, e. Blocks of salt ready to be put into
the bags and drawn up.
  When this salt is impure, it must be dis-
solved in water,  in order to purify it.
  The water  of the ocean contains our
most ample store of salt, but not the rich-
est.  If we had  no means of obtaining the
muriate of soda  from it, but by the heat of
fires, salt would  be  an expensive article of
consumption.  Recourse,  therefore,  has
been had to two methods of attaining this
purpose: 1st, by natural  evaporation; 2d,
by natural and artificial evaporation com-
bined.
  In the first case, the salt is extracted by
means of brine-pits.  These are large shal-
low  pits, the bottom of which is  very
smooth, and  formed of clay.   They  are
made near the sea-shore, and consist of,
  1st, A large reservoir,  deeper than the
proper brine-pits, and dug between them
and the sea.  This reservoir communicates
with the sea by  means of a channel provi-
ded with a sluice.   On the sea-shore, these
reservoirs may be filled at high water, but
the tides are rather inconvenient than ad-
vantageous to brine-pits.
  2dly, The brine-pits properly so called,
which are divided  into a number of com-
partments by means of little  banks.  All
these compartments have a communication
with each other, but so that the water fre-
quently has a long circuit to make from one
set to  another.  Sometimes it has  four  or
five hundred yards to flow before it reaches
the extremity of this sort of labyrinth. The
various divisions have a number of singular
names, by which they are technically dis-
tinguished, and  differing much in different
places.
  The brine-pits should be exposed to the
north, north-east, or north-west winds.
  Plate  IX. exhibits  a plan  of a set of
brine-pits.
  A, A. The great reservoir, into which
the water flows  through the sluice a.
  B, B, B.   The second reservoir.  Into
this  the water  enters by a  subterranean
channel at b, and, circulation through the
several divisions in the  direction of the
shaded line, finds its exit  at d.
  c, c, c, c.   Narrow banks of earth sepa-
rating the divisions.
  C, C, C.   The third reservoir.  The wa-
ter, on quitting  the  second reservoir,  en-
ters, through  an aperture at  d, the long
narrow channel d, e, f, g, h, whence it flows
into C, C, C, as it had before done into  B,
B, B.
  D, D, D, D. The fourth reservoir, into
which the water flows, as shown  in the
plate, from the third reservoir;  and from
which it is  ultimately distributed  among
the small square basins E, E, E, E, E,  E,
E,E.
  i, i, i, i.   Heaps of salt drawn out of the
basins E, E, and left to drain.
  K,  K.  The salt  collected together in
larger heaps, and left to drain still more.
  The water of the sea is let into these re-
servoirs in the month  of March. It af-
fords, as is apparent, a  vast surface for
evaporation.  The first reservoir is intend-
ed to detain the water till  its impurites
have  subsided, while at the same  time the
evaporation commences in  it.   From this
the other reservoirs are supplied, as their
water evaporates.  The salt is considered
as on the point of  crystallizing, when the
water begins to grow red.  Soon after
this, a pellicle forms on the surface, which
breaks, and falls to the bottom. Some-
times the salt is  allowed to  subside in the
first compartment, sometimes it is made to
pass on to  othcs, where a larger surface
is exposed to the air.  In either case the
salt is drawn out, and left upon the borders
of the pans to d'ain and dry.  In  this way
it is collected tw> or three  times a-week,
toward the end o* the operation.
  The salt thus obtained, partakes of the
colour of the bottom on  which it is form-
ed; according to tie nature of which, it is
white, red, or gray  The last is frequently
called green salt.  Sea-salt has  the incon-
venience of tasting1 bitter,  if used imme-
diately after it is riade-  This is owing to
the muriate of line and sulphate  of soda,
with  which it is contaminated.  By  expo-
sure  to the air for two or three  years it is
in part freed from these salts.

     Explanation of Plates X. and XL
  Fig. 1.  Plan of the salt pans.
  No. 1. Small pan,
  No. 2. Graduating pan.
  No. 3. Preparing pan.
  No. 4. Crystallizing pan.
  The  arrangement of the plates of iron,
which compose these  pans, is shown in
No. 2.
  a, a.  Elevation on which the salt is  pla-
ced to drain, as  it is taken from the crys-
tallizing pans.
  b, b, b. Wooden partitions, which sepa-
rate the chambers.
  c, c, c. A raised  wooden  ledge, which
surrounds the pans.
  Fig. 2. Section of the evaporating cham-
ber, which contains the pans 1  and 2, in
the line C, D.
  d, d, d.  Heat-tubes, which give heat to
the small pan, and contribute to  heat the
others.
  e, e, e. Fire-place for the pans.
  *', i, i. Pillars of cast iron, over  the gra-
tings  g, g, g, which support the bottoms of
the pans.
  h. Wooden chamber, which contains the-
two pans. 
SAL
SAL
   fc. Opening by which the vapours escape.
   .Fig*. 3.  Section ofthe evaporating cham-
ber, which contains the pans 3 and 4, in
the line A, B.
   a. Elevation on which the salt from the
crystallizing pans is placed to drain.
   The other letters indicate the same parts
as in the preceding figures.
   Fig. 4.  Method  in which  the plates  of
iron are joined to form the pans.
   a. The  iron plate.
   b. The  iron gutter, which  receives the
edges of the plates, and is strongly fasten-
ed with screws.
   i, i. Pillars of cast iron,  which support
the bottom of the pan.
   Sometimes the water is evaporated  to
dryness; but this is rarely done, because
for this the water must contain no muriate
of soda.   Commonly the  mother-water  is
left, containing chiefly tiie  deliquescent
salts, which are muriates «f lime and mag-
nesia.  These salts, while :hey increase the
bulk of the mother-water add also to the
consumption of fuel, and render  the salt
obtained bitter and deliqiescent.
   When saline waters contain but a small
quantity of salt, the evaporation of it  by
fire in its  natural state would be too ex-
pensive.   It must be concentrated there-
fore by some cheaper rr.ode.
   Now it  is well known, that, to promote
and accelerate the evaporation of a fluid,
it should be made to present  a  large sur-
face to the air.   To effect this,  the water
is  pumped up to the height of nine or ten
yards, and made to fall on piles  of faggots
built up in the shape of a  wall.  The wa-
ter, distributed  uniformly  over these  by
means  of  troughs, is minutely divided  in
its descent,  and thus experiences a consi-
derable evaporation.  The  same  water  is
frequently pumped up twenty  times  or
more, to bring it to the degree of concen-
tration necessary.  This operation is call-
ed graduating, and the piles of thorn fag-
gots thus erected are termed  graduation
houses.
   These piles are covered with a roof,  to
shelter them from the rain, are made about
five yards thick, and are sometimes  more
than four hundred  yards long.    They
should be so constructed that their  sides
may face the prevailing winds.
   Plate XII.  represents a graduation house
at Bex, with the improvements lately made
in it by M. Fabre.
   A.  Transverse section of the building.
   B.  Longitudinal section.
   e, e, c. The faggots of thorns, piled up
in two tiers below, and  one above.
   a, a. Wooden troughs, to distribute the
salt water over these faggots.
   C, C. Plan and perspective view of these
troughs.
   b, b, b. Angular notches, through which
the water runs out in slender streams, pre-
senting a large surface  to the air.
   e. Roof, covered with tiles, not laid flat,
but raised so as to admit a free circulation
of air between them.
   d, d. Reservoir, into which the concen-
trated salt water flows,  and from which it
is pumped up to the troughs, to be distri-
buted afresh  over the faggots.
   The state of the air has a considerable
influence on the celerity of the concentra-
tion.  A cool, dry, and moderate wind is
favourable to it; while dull, damp, and fog-
gy weather sometimes  even adds to the
quantity of water.
   The principal uses of the  muriate of
soda have already been mentioned under
the article muriatic acid. In addition it may
be observed, that almost all graminivorous
animals are fond of it, and that it appears
to be  beneficial to them, when mixed with
their food.  Wood steeped in a solution of
it, so as to be thoroughly impregnated with
it, is  very  difficult of combustion: and in
Persia it is supposed to prevent timber
from  the attack of worms, for which pur-
pose it is used in that country.   Bruce in-
forms us, that  in Abyssinia it  is used as
money; and it  is very probable, that the
pillars of fossil glass, in which the Abys-
sinians are said by Herodotus to have en-
closed the bodies of their relations, were
nothing but masses of rock salt,  which is
very common in that part of Africa.
   Salt was supposed by the ancients to be
so detrimental to vegetation, that, when a
field  was condemned to  sterility, it was
customary  to sow it with  salt.   Modern
agriculturists,  however, consider it  as a
useful manure.
   • We  are indebted to Dr. Henry for a
very  able and  elaborate  investigation of
the different varieties of common salt. The
following table contains the general state-
ment of his experiments. 
SAL
SAL
1000 parts by weight consist of
		is*	B fell 5?		2 2 ^ a: £		3 gs	£S	3 S kj & *-*■ a & 40	Pure
	Kind of salt.	<» s.	S 8	t^ a	k .4. -^. 3 k£>		It 4*	5- S 28		muriate of soda. 960
t! "5	CSt. Ube's,	9	trace	3	3	234				
o *	< St. Martin's,	12	do.	3*	3*	19	6	25	40}	959*
	(.Oleron,	10	do.	2	2	19*	4*	23£	35|	964i
*s>	fScotch (common),	4	_	28	28	15	m	32$	64	935$
	J Scotch (Sunday), S Lymington(common) iDitto (cat),	1	—	ni	11*	12	4J	16*! 29		971
"! P"		2	—	11	11	15	35	50	63	937
(3^ «•		1	—	5	5	1	5	6	12	988
w	fCrushed rock,	10	O.tV oi	0-tV	o.i	6*	__	6*	16j	983i
	J Fishery,	1		04	1	Hi	—	ni	13i	986£
J*S	] Common,	1	o.i	04	1	14*	—	144	164	983*
(J	tstoved,	1	0.4	o.i	1	15*	—	15i	17*	982*
  " In sea salt prepared by rapid evapora-
tion, the insoluble portion is a mixture of
carbonate of lime with carbonate of mag-
nesia, and a fine siliceous sand; and in the
salt prepared from Cheshire brine, it is al-
most entirely carbonate of lime. The in-
soluble part of the less pure pieces of rock
salt is chiefly a marly earth, with some sul-
phate of lime.  The quantity of this im-
purity, as it is stated in the table, is consi-
derably below the average, which in my
experiments  has varied from 10 to 45 parts
in 1000. Some estimate of its general pro-
portion, when ascertained on a larger scale,
may be formed from the fact, that govern-
ment, in levying the duties, allow 65 pounds
to the  bushel of rock salt, instead of 56
pounds, the  usual weight of a  bushel of
salt."—Henry.  Phil. Trans, for  1810, part
1st.  The  enormous contamination of the
Scotch variety with that septic bitter salt,
muriate of magnesia, accords perfectly with
my own experiments, and is a reproach to
the country.
  " That kind of salt then," says this able
chemist, " which possesses most eminently
the combined properties of hardness, com-
pactness, and perfection of crystals, will be
best adapted to the purpose of packing fish
and other provisions; because it will remain
permanently  between the different layers,
or will be very gradually dissolved by the
fluids that exude from the provisions; thus
furnishing a  slow but constant  supply of
saturated brine.  On the other hand, for
the purpose of preparing the pickle, or of
striking the meat, which is done by immer-
sion  in  a  saturated solution  of salt, the
smaller grained varieties answer equally
well; or, on account of their greater solu-
bility, even better," provided they be equal-
ly pure.  His experiments show, that in
compactness of texture the large grained
British salt is equal to the foreign bay salt.
Their antiseptic  qualities  are  also  the
same.*
  Salt (Ammoniacal, Fixed).   Muri-
ate of lime.
  S alt ( Ammoniacal, Secret) of Glau-
ber.   Sulphate of ammonia.
  Salt (Arsenical, Neutral) of Mac-
quer.  Superarseniate of potash.
  Salt (Bitter,Cathartic). Sulphate
of magnesia.
  Salt (Common). Muriate of soda.  See
Acid (Muriatic): also end of the article
Salt, and Rock Salt.
  Salt (Digestive) op Sylvius. Ace-
tate of potash.
  Salt (Diuretic).   Acetate of potash.
  Salt (Epsom).  Sulphate of magnesia.
  Salt (Febrifuge) of Sylvius. Mu-
riate of potash.
  Salt (Fusible). Phosphate of ammo-
nia.
  Salt (Fusible) of Urine.  Triple
phosphate of soda and ammonia.
  Salt (Glauber's).  Sulphate of soda.
  Salt (Green).  In the mines of Wie-
liczka the workmen give this name to the
upper stratum of native salt, which is ren-
dered impure by a mixture of clay.
   Salt (Marine).  Muriate of soda.
  Salt (Marine, Argillaceous).  Mu-
riate of alumina.
  Salt (Microcosmic).  Triple phos-
phate of soda and ammonia.
  Salt (Nitrous Ammoniacal).  Ni-
trate of ammonia.
  Salt of Amber.  Succinic acid.
  Salt of Benzoin.  Benzoic acid.
  Salt of Canal. Sulphate of magne-
sia.
  Salt ofColcothar. Sulphate of iron.
   Salt of Egra.   Sulphate of magnesia.
   Salt of Lemons (Essential).  Su-
peroxalate of potash.
   Salt of Saturn.   Acetate of lead. 
SAP
SAT
  Salt or Sedlitz.  Sulphate of mag-
 nesia.
  Salt of Seicnette.  Triple tartrate
 of potash and soda.
  Salt of Soda.  Subcarbonate of soda.
  Salt of Sorrel. Superoxalate of pot-
 ash.
  Salt of Tartar. Subcarbonate of pot-
 ash.
  Salt o» Vitriol.  Purified sulphate
 of zinc.
  Salt of Wisdom. A compound muri-
 ate  of mercury and ammonia.  See Alem-
 broth.
  Salt (Perlate).  Phosphate of soda.
  Salt (Polychrest) ofGlaser. Sul-
 phate of potash.
  Salt (Sedative).  Boracic acid.
  Salt (Spirit of).  Muriatic acid was
 formerly called by this name, which it still
 retains in commerce.
  Salt (Sulphureous) ofStahl. Sul-
 phite of potash.
  Salt (Wonderful). Sulphate of soda.
  Salt (Wonderful Perlate). Phos-
phate of soda.
  Saltpetre.  Nitrate of potash.
  Sand.   Sand is an assemblage of small
stones.
  Sand-bath.   See Bath.
  Sandaric Gum.  A resin in yellowish-
white tears, possessing a considerable de-
gree of transparency.
  Sandiver, or Glass-gall.  This is a
saline matter, which rises as a scum in the
pots or crucibles  in which glass is made.
  •Sanguification.  That process of
living animals by which chyle is converted
into blood.  I had entertained hopes of be-
ing  able to present some definite facts on
this mysterious subject, but have been dis-
appointed.  The  latest and  best essay  on
sanguification is that of Dr.  Prout,  in the
Annals of Philosophy for April 1819.*
  •Sappare. Cyanite.*
  •Sapphire.   A sub-species  of  rhom-
boidal corundum. It is the Telesieof Haiiy,
and the perfect corundum of  Bournon. The
oriental ruby and topaz are sapphires.
  Colours blue and red; it occurs also gray,
white, green, and yellow. It occurs in blunt
edged pieces, in roundish pebbles, and crys-
tallized.  The primitive figure is a slightly
 acute rhomboid, or double three-sided py-
ramid, in which  the  alternate angles are
86° 4' and 93° 56'.  The following are the
usual forms:—a  very acute, equiangular,
 six-sided pyramid; the same truncated on
the  summit; a perfect six-sided prism;  an
 acute, double, six-sided pyramid; the same
 acuminated, or truncated in  various ways.
 Splendent,  inclined to adamantine.   Clea-
 vage parallel with  the terminal  planes of
 the  prism.  Fracture conchoidal.  From
 transparent to translucent.  Refracts dou-
 ble.  After diamond, it is the hardest sub-
stance in nature.  The blue variety or sap-
phire, is harder than the  ruby.  Brittle.
Sp. gr. 4 to 4.2.  Its constituents are,
                 Blue.        Red.
  Alumina,       98.5         90.0
  Lime,            0.5           7.0
  Oxide of iron,    1.            1.2
                        loss     1.8

                 100.0         100.0
               Klaproth.      Chenevix.

Infusible before the blow-pipe.  It becomes
electrical by rubbing, and retains its elec
tricity for several hours; but does  not be-
come electrical by heating.  It occurs in
alluvial soil, in the vicinity of rocks belong-
ing to the secondary or floetz-trap forma-
tion, and imbedded in gneiss. It is found at
Podsedlitz andTreblitz in Bohemia, and Ho-
henstein in Saxony; Expailly in France; and
particularly beautiful in the Capelan moun-
tains, 12 days journey from Sirian  a city of
Pegu.  Next to diamond, it is the most va-
luable of the gems. The white and pale blue
varieties, by exposure to heat, become snow-
white, and  when cut exhibit so high a de«
gree of lustre, that they are used  in  place
of diamond.  The most highly  prized va.
rieties are the crimson  and carmine-red;
these are the oriental ruby of the jeweller;
the next is sapphire,  and last, the  yellow,
or oriental topaz. The asterias or star-stone,
is a very beautiful variety, in which the co-
lour is generally of a reddish-violet, and
the form a rhomboid, with truncated apices,
which exhibit an opalescent lustre. A sap-
phire of 10 carats weight, is considered to
be worth fifty guineas.—Jameson.*
  • Saphirin.  Haiiyne.*
  * Sarcolite.  A variety of  analcime.*
  * Sarde, or Sardoin, a variety of car-
nelian, which  displays on  its  surface an
agreeable  and rich reddish-brown colour,
but appears of a deep blood-red, when held
between the eye and the light.-
  • Sardonyx.  Another variety,  com-
posed of layers of white and red carnelian."
  •Sassoline.  Native boracic acid.  It
is found on the edges of hot springs near
Sasso, in the territory of Florence. It con-
sists of boracic  acid 86, ferruginous sul-
phate ofmanganese 11, sulphate of lime 3.
—Klaproth.*
  * SatinSpar. Fibrous limestone; whieh
see.*
  Saturation.  Some substances unite
in  all proportions.  Such, for example, are
acids in general, and some of the salts with
water; and many of the metals with each
other. But there are  likewise  many sub-
stances which  cannot be dissolved  in a flu-
id, at a settled temperature, in any  quan-
tity  beyond a  certain  proportion.  Thin
water will dissolve only about one-third of
its weight of common salt; and, if  more be 
SCA                                  SCH
added, it will remain solid. A fluid, which
holds in solution as much of any substance
as it can dissolve, is said to  be saturated
with it. But saturation with one substance
does not deprive the fluid of its power  of
acting on and dissolving some other bodies,
and in many cases it increases this power.
For example, water saturated with salt will
dissolve sugar; and water saturated with
carbonic acid  will dissolve  iron, though
without this addition its action on this me-
tal is scarcely perceptible.
  The word saturation is likewise used in
another sense by chemists: the union of two
principles produces a body, the properties
of which differ from those of its component
parts, but resemble those of  the  predomi-
nating principle.  When the principles are
in such proportion that  neither  predomi-
nates, they  are said to be saturated with
each other;  but if otherwise, the most pre-
dominant principle  is said to be  sub-satu-
rated or undersaturated,  and the other su-
persaturated or oversaturated.
  "Saussurite. Colours white, gray, and
green. Massive, disseminated, and in rolled
pieces. Dull.  Fracture splintery. Faintly
translucent  on the edges. Difficultly fran-
gible.  Hard, scratching  quartz.  Meagre
to the feel.   Sp. gr. 3.2.   It melts on  the
edges and angles. Its constituents are,  si-
lica 49, alumina 24, lime 10.5, magnesia
3.75, natron 5.5, iron 6.5—Klaproth. It oc-
curs at the foot of Mount Rosa.   Professor
Jameson places it near Andalusite.*
  • Scales of F'ish, consist of  alternate
layers of membrane and phosphate of lime.*
  • Scales of Serpents, are composed
of a horny membrane, without the calcare-
ous phosphate.*
  • Scammohy consists  of
Aleppo.	Smyrna.
Besin, 60	29
Gum, 3	8
Extractive, 2	5
Vegetable debris"? o-and earth, 5 —	58
	
100	loo
           Vogel, and Bouillon Lagrange.*
  * Scapolite,  or Pyramidal Feld-
spar.   Professor  Jameson divides it into
four sub-species; radiated, foliated,  com-
pact red, and elaolite.
  1. Radiated.   Colour gray.  Massive, in
distinct concretions and crystallized.  Pri-
mitive  figures a pyramid of 136° 38' and
62° 56'.  The secondary forms are, a rec-
tangular four-sided prism, acuminated or
truncated-  Lateral planes deeply longitu-
dinally streaked. Resinous, pearly. Cleav-
age double. Fracture fine grained uneven.
Translucent.   As hard as apatite. Easily
frangible.  Sp. gr. 25 to 2 8.  Green sca-
polite  becomes white before the blow-pipe,
and melts into a white glass.  Its consti-
   Vol. 11.
tuents are, silica 45, alumina 33, lime 17.6,
natron 1.5, potash 0.5, iron and manganese
1.—Laugier.  It occurs in the neighbour-
hood  of Arendal  in  Norway, associated
with magnetic ironstone, feldspar, &c.
  2. Foliated scapolite.  Colours gray, green,
and  black.   Massive, disseminated, and
crystallized in low eight-sided prisms, flat-
ly  acuminated with four planes.  Splen-
dent, vitreous.  Fracture small grained un-
even. Translucent.  Streak white. Brittle.
Hardness and sp. gr. as preceding species.
Itis found in granular granite or whiiestone,
in  the Saxon Erzegebirge.
  3. Compact scapolite. Colour red.  Crys-
tallized in long, acicular, four-sided prisms,
which are often curved. Glistening. Opaque-
Hard in a low degree.  Easily frangible.
It occurs with the  others in metalliferous
beds at  Arendal.
  4. See Elaolite.*
  •Schaalstein. See Tabular Spar.*
  * Schaum Earth.   See Aphritb.*
  • Scheelium.   Tungsten.*
  •Schiefer Spar.  See Slate Spar.*
  * Schiller  Spar. This  species con-
tains  two sub-species; bronzite and com-
mon schiller spar.  See Bronzite.*
   Common schiller spar. Colour olive green.
Disseminated, and in granular distinct con-
cretions.  Splendent  and metallic-pearly.
Cleavage  single.  Opaque.   Softer than
bronzite.  Streak  greenish  gray.   Easily
frangible.  Sp. gr. 2.882?  It occurs  im-
bedded  in serpentine in Fetlar and Unst in
Shetland, and at Portsoy in Banffshire; also
in  Skye, Fifeshire, Calton-hill, near Dum-
barton,  between Ballantrae and Girvan in
Ayrshire, and in Cornwall.
  Labradore  schiller  spar.  See  Hyper-
stene.*
   * Scillitin. A white transparent, acrid
substance, extracted  from squills; by Vo-
gel .*
  • Schmelzetein.   Dipyre.*
  • Schorl  (Common).  A sub-species
of rhomboidal tourmaline.  Colour velvet-
black. Massive, disseminated, and crystal-
lized in three, six, and nine-sided prisms.
Crystals acicular.  Lateral planes, longitu-
dinally  streaked.  Between  shining  and
glistening. Fracture conchoidal, or uneven.
Opaque.  Streak gray. As hard as quartz.
Easily frangible.  Sp. gr. 3. to 3.3.  It
melts into a blackish slag. Its constituents
are, silica 36.75, alumina 34.5,  magnesia
0.25, oxide of iron 21,  potash 6, and a trace
of manganese.—Klaproth. It exhibits the
same electric properties as tourmaline.  It
occurs imbedded in granite, gneiss, &c. in
Perthshire, Banffshire, Cornwall, &c*
  * Schorl (Blue).   A variety of  Haiiy-
ne.*
  * Schorl (Red   and  Titanitic).
Rutile.*
                      3 4 
SEL
SEL
  • Schorlite, or Schorlous Topai.
Pycnite of Werner.  Colour, straw-yellow.
Massive, composed  of parallel  prismatic
concretions, and crystallized in  long six-
sided prisms.  Glistening, resinous.  Frac-
ture, small conchoidal.  Translucent on the
edges.  Nearly as hard as common topaz.
Brittle. Sp. gr. 3.53.  Infusible.  Becomes
electric by  heating.  Its constituents are,
alumina 51,  silica  38.43, fluoric  acid 8.84.
—Berzelius.  It occurs at Altenburg in Sax-
ony, in a rock of quartz and mica, in por-
phyry.*
  •Selenium.  A new elementary body,
extracted by M. Berzelius from the pyrites
of Fahlun,  which, from  its  chemical pro-
perties, he places between sulphur and tel-
lurium, though  it has more properties  in
common with the former than with the lat-
ter substance.  It was obtained in exceed-
ingly small quantity from a large  portion  of
pyrites. For the mode of extraction I must
refer  to his long and elaborate papers,
translated from the  Annales de  Chimie  et
Physique, ix. et seq. into the Annals of Phi-
losophy, for June, August,  October, and
December 1819, and  January 1820.
  When selenium, after being fused, be-
comes solid, its  surface assumes  a metallic
brilliancy of a very deep brown colour, re-
sembling polished haematites.  Its fracture
is conchoidal, vitreous,  of  the  colour  of
lead,  and perfectly metallic.   The powder
of  selenium has a deep red  colour, but it
sticks together readily  when pounded, and
then assumes a gray colour and  a smooth
surface, as  happens  to antimony and bis-
muth.  In very thin coats, selenium is trans-
parent, with  a ruby-red colour.   When
heated it softens;  and  at  212° it is semi-
liquid, and melts completely at a tempera-
ture  a few degrees  higher.  During its
cooling it retains for  a long time  a soft and
semi-fluid state. Like Spanish wax, it may
be kneaded  between the fingers, and drawn
out into long threads,  which have a great
deal of elasticity, and in which we easily
perceive the transparency, when they are
flat and thin.  These  threads, viewed  by
transmitted light, are red; but, by reflected
light, they are gray, and have the metallic
lustre.
   When selenium is heated  in a retort, it
begins to boil at a temperature below that
of a  red heat.   It assumes  the  form of a
dark yellow vapour,  which, however, is not
so intense as that of the vapour of sulphur;
but it is more  intense than chlorine gas.
The vapour condenses in the neck of the
retort, and  forms black drops, which unite
into larger drops, as  in the distillation of
mercury.
   If we heat selenium in the air, or in ves-
 sels so large, that the  vapour  may be con-
•densed by the  cold air,  a  red smoke is
 formed, which has no particular  smell, and
which is condensed in the form of a cinna-
bar-red powder, yielding a species of flow-
ers, as happens to sulphur in the same cir-
cumstances.  The  characteristic smell of
horse-radish is not  perceived, till the heat
becomes great enough to occasion oxida-
ion.
  Selenium  is  not a good conductor of
heat.   We can  easily hold  it  between the
fingers, and melt it at the distance  of one
or two lines from the fingers, without per-
ceiving that it becomes  hot.  It is also a
non-conductor of electricity.  On the other
hand, M. Berzelius was not able to  render
it electric by friction.  It is not hard; the
knife scratches it  easily.  It is brittle like
glass, and is easily reduced to powder. Its
sp. gr.  is between 4.3 and 4.32.
   The affinity of selenium for oxygen is not
very great.  If we heat it in the air, with-
out touching it with a burning body,  it is
usually volatilized without alteration; but
if it is touched by  flame, its edges assume
a fine sky-blue colour, and it is volatilized
with a strong smell of horse-radish.  The
odorous substance is a gaseous oxide of se-
lenium, which, however, has not been ob-
tained in an insulated state, but only mixed
with atmospherical air.   If we heat seleni-
um in a close phial filled with common air,
till the greatest part of it is evaporated,
the air  of the phial  acquires the odour of
oxide of selenium in a  very high degree.
If we wash the air  with pure water, the li-
quid acquires the odour of the gas;  but as
there are always formed traces of  selenie
acid, this water acquires the property of
reddening litmus paper feebly, and of be-
coming muddy when mixed with  sulphu-
retted hydrogen gas.  Selenic oxide gas is
but  very little soluble in water, and does
not communicate any taste to it.
   If we heat selenium in a large flask filled
with  oxygen  gas, it evaporates  without
combustion, and the  gas assumes the odour
of selenic oxide, just as would have hap-
pened,  if  the  sublimation had taken place
in common  air; but if we heat the selenium
in a glass ball of an inch diameter, in which
it has not  room to volatilize and disperse;
and if we allow a current of oxygen gas to
pass through this  ball,  the selenium takes
fire, just when it begins  to boil,  and bum9
with  a feeble flame, white towards the
base,  but   green  or greenish-blue at the
summit, or  towards  the upper edge.  The
oxygen gas is absorbed, and selenic acid
is sublimed into the  cold parts ofthe appa-
ratus.   The selenium is completely consu-
med without any  residue.   The excess of
oxygen gas usually  assumes the odour of
selenic oxide.  Selenic acid is in the form
of very long four-sided needles.  It seems
to be most readily  formed  by the action
of nitro-muriatic  acid on selenium.  The
selenic acid does not melt with heat; but 
SEP                                   SHE
it diminishes a little in bulk  at the hottest
place,  and then assumes the  gaseous form.
It absorbs a little moisture from the air, so
that the crystals adhere  to each other, but
they do not deliquesce.  It has a pure acid
taste, which leaves a slightly burning sen-
sation on the tongue.  It is very soluble in
cold water,  and dissolves in almost every
proportion in boiling water.  M. Berzelius
infers the composition of selenic acid, from
several experiments, to be,
Selenium, 71.261  100.00  1 prime  4.96
Oxygen,   28.739   40.33  2 primes 2.00
  If into a solution of selenic acid in muri-
atic acid, we introduce a piece of zinc or of
polished  iron,  the  metal  immediately  as-
sumes the colour of copper, and  the sele-
nium is gradually precipitated in  the form
of red, or brown or blackish  flocks, accord-
ing as the temperature is more or less ele-
vated.  When seleniate of potash is heated
with muriate of ammonia, selenium is  ob-
tained by the deoxidating property of the
ammonia; but in this case we always lose
a small quantity of selenium, which comes
over with the  water in the form of an acid.
If we pour dilute muriatic acid on  the com-
pound of selenium and potassium dissolved
in  water, seleniuretted  hydrogen gas is
evolved. Water impregnated with it preci-
pitates all the metallic solutions, even those
of iron and zinc, when they are neutral.
Sulphur, phosphorus, the earths, and the
metals combine with selenium, forming se-
leniurets.  Selenic acid neutralizes the ba-
ses.   Selenium has  been recently found in
 two minerals, one is from Skrickerum, in
the parish of Tryst-rum in Smoland.*
   • Scorza..   A variety of epidote."
   • Sea Froth.  Meerschaum*
   Sea Salt.  Muriate of soda. See Acid
 (Muriatic), and Salt.
    * Sea Wax. Maltha, a white, solid, tal-
 lowy looking  fusible substance, soluble  in
 alcohol,  found on the Baikal Lake in Sibe-
 ria.*
   •Sebacic  Acid. See Acid (Sebacic).*
    Sebatk. A neutral compound of sebacic
 acid with a base.
   Sedative Salt.  Boracicacid.
    Sel de Seignette.  The triple tar-
 trate of potash and soda, or Rochdle salt.
 See Acid (Tartaric).
    • Selenite.  Sparry gypsum.*
    • Semiopal.  See Opal.*
    * Septaria, or ludi helmontii, are sphe-
  roidal concretions  that  vary  from a few
  inches to a foot in diameter. When broken
  in a longitudinal direction, we observe the
  interior of the mass intersected by a num-
  ber of fissures, by which it is  divided into
  more or less  regular prisms, of from 3 to 6
  or more sides, the fissures being sometimes
  empty,  but oftener filled  up with another
  substance, which is generally calcareous
  spar.  The body of the concretion is a fer-
ruginous marl.  From these septaria  are
manufactured  that excellent material for
building under water, known by the name
of Parker's or  Roman cement.—Jameson*
   * Serosity.  See Blood.*
   * Serpentine; common and precious.
   1. Common.  Colour  green,  of various
shades.  Massive.  Dull.  Fracture, small
and  fine  splintery.  Translucent  on  the
edges.  Soft,  and scratched by calcareous
spar.  Sectile.  Difficultly frangible.  Feels
somewhat greasy. Sp. gr. 2.4 to 2.6. Some
varieties are  magnetic  Its  constituents
are, silica 32,  magnesia 37.24, alumina 0.5,
lime 10.6, iron  0.66: volatile  matter  and
carbonic acid  14.16.—Hisinger.  John  and
Rose give 10.5 of water in it.   It occurs in
various mountains. It is found in Unst and
Fetlar  in Shetland;  at Portsoy;  between
Ballantrae and Girvan; in Cornwall; and in
the county of  Donegal.
   2. Precious  serpentine.  Of this there are
two kinds, the splintery and conchoidal.
   a.  Splintery.  Colour dark leek-green.
Massive.  Feebly  glimmering.   Fracture
coarse splintery.  Feebly translucent. Soft.
Sp. gr. 2-7. It occurs in Corsica, and is cut
into snuff-boxes, &c.
   b. Conchoidal. Colour leek-green. Mas-
 sive and disseminated. Glistening, resin-
 ous.  Fracture  flat  conchoidal.  Translu-
 cent.   Semi-hard.  Sp. gr. 26. Its consti-
 tuents are, silica 42.5, magnesia 38.63, lime
 0.25, alumina 1, oxide of iron 1 5, oxide of
 manganese 0.62, oxide of chrome 0.25, wa-
 ter  15.2.—John. It occurs with foliated gra-
 nular  limestone in   beds  subordinate  to
 gneiss, mica-slate, &c.  It is found at Port-
 soy, in Banffshire; in the Shetland Islands,
 and in the Island of Holyhead. It receives
 a finer polish than common serpentine.*
   • Serum.  See Blood and Milk.*
   •   Shale.   Slate-clay  and  bituminous
 slate-clay*
   Shells. Marine shells may be divided,
 as Mr. Hatchett observes, into two kinds:
 Those that  have  a  porcellanous  aspect,
 with an enamelled surface, and when bro-
 ken are often in a slight degree of a fibrous
 texture;  and those that have generally, if
 not  always,  a strong epidermis, under
 which is the shell, principally or  entirely
 composed of the substance called nacre, or
 inother-of-pearl.
    The porcellanous shells appear to consist
 of  carbonate of lime, cemented  by a very
 small portion of animal gluten.  This ani-
 mal gluten is more abundant in some, how-
  ever, as in the  patellae.
    The mother-of-pearl shells are composed
  ofthe same  substances-  They differ, how-
  ever, in their structure, which is lameiiar,
  the gluten forming their membranes, regu-
  larly alternating with strata of carbonate of
  lime. In these too the gluten is much more
  abundant. 
BIE
SIL
  Mr. Hatchett made a few experiments on
land shells also, which did not exhibit any
differences.   But the shells of the crusta-
eeous animals he found to contain more or
less phosphate of lime,  though not equal
in quantity to the carbonate, and hence ap-
proaching to the nature of hone.  Linnaeus
therefore  he observes was right in consi-
dering the covering of the echini as crus-
taceous, for it contains phosphate of lime.
In the covering of some of the species of
asterias too, a little phosphate of lime oc-
curs; but  in that of others there is none.
Phil. Trans.
  *  Shistus  (Argillaceous).   Clay-
slate.*
  * Siberite.  Red tourmaline.*
  • Sidero-calcite.  Brown spar.*
  • Siderum. Bergmann's name for phos-
phuret of iron.*
  • Sienite or Syenite.  A compound
granular  aggregated  rock, composed of
feldspar  and hornblende, and  sometimes
quartz and  black mica.   The hornblende
is the characteristic ingredient, and distin-
guishes it perfectly  from  granite, with
which it is often confounded; but the feld-
spar, which is almost  always red, and sel-
dom inclines  to  green,  forms  the most
abundant  and essential ingredient  of the
rock.   Some varieties contain a very con-
siderable  portion of quartz and mica, but
little hornblende.  This is particularly the
case with the Egyptian varieties, and hence
these are often confounded with real gra-
nite.
  As it has many points of agreement with
greenstone, it is necessary to compare them
together.   In  greenstone, the hornblende
is usually the predominating ingredient; in
sienite, on the contrary,  it is the feldspar
that predominates. In greenstone, the feld-
spar is almost  always green, or greenish;
here, on the contrary, it is  as constantly
red, or reddish. Quartz and mica are very
rare in greenstone, and in inconsiderable
quantity; whereas they are rather frequent
in sienite.  Lastly, greenstone commonly
contains iron pyrites,  which  never  occurs
in sienite.
  It has  either a simple granular base, or
it is granular  porphyritic; and  then it is
denominated  porphyritic  sienite.  When
the parts of the granular base are so  minute
as to be distinguished with difficulty, and
it contains imbedded in it large crystals of
feldspar, the  rock is termed sienite-por-
phyry.  It is sometimes unstratified, some-
times very distinctly  stratified.   It  some-
times shows a tendency  to the columnar
structure.  It  contains no  foreign beds.  It
occurs in unconformable and  overlying
stratification,  over  granite, gneiss, mica-
Blate, and clay-slate, and is pretty continu-
ous, and covers most of the  primitive
rocks.   It is  equally  metalliferous  with
porphyry.  In the Island of Cyprus,  it af.
fords much copper;  many ofthe important
silver and gold  mines in Hungary are situ-
ated in it.  The sienite of the Forest of
Thuringia affords iron.   In  this country,
there is a fine example of sienite, in  Callo-
way, where it forms a considerable portion
of the hill called Criffle.  On the Continent,
it occurs  in the Electorate of Saxony;  and
in Upper Egypt, at the city of Syena, in
Thebaid, at the cataracts  of the Nile,
whence it derives its name.  The Romans
brought it from that  place to  Rome, for
architectural  and   statuary  purposes.—
Jameson.*
   *  Silica.  One  of the primitive earths,
which in consequence of Sir  H. Davy's re-
searches on the metallic bases of the alkalis
and earths,  has been recently regarded as
a compound of  a peculiar combustible prin-
ciple with oxygen.  If  we ignite powdered
quartz  with three parts of pure potash in
a  silver crucible, dissolve the  fused com-
pound in water, add to the solution a quan-
tity of acid, equivalent to  saturate the al-
kali, and evaporate to dryness, we shall
obtain a fine gritty powder, which  being
well washed with hot water, and ignited,
will leave pure silica.   By passing the va-
pour of potassium over silica in an ignited
tube, Sir H. Davy obtained a dark-coloured
powder, which  apparently contained  sili-
con, or  silicium, the basis  of the  earth.
Like boron and carbon, it is capable of sus-
taining a high temperature without  suffer-
ing any change.  Aqueous  potash seems to
form with  it  an  olive-coloured solution.
But as this basis is decomposed by  water,
it was not possible to wash away the potash
by this  liquid.   Berzelius and Stromeyer
tried to form an alloy of silicon  or silicium
with iron,  by  exposing to  the strongest
heat of a blast furnace, a mixture of three
parts of iron, 1.5 silica,  ard  0.66 charcoal.
It was in the state of fused globuks. These,
freed  from the charcoal,  were white and
ductile, and their solution in muriatic acid
evolved  more  hydrogen  than  an  equal
weight of iron.  The  sp. gravity  of the
alloy was from 6 7  to 7.3, while that of the
iron used was 7.8285  From Mr. Mushet's
experiments, however, as  well as from the
constitution  of plumbago, we  know  that
carbon will combine with  iron  in very con-
siderable proportions, and that in certain
quantities, it can give it a whitish  colour
and inferior density.  Nothing definitive
therefore can be inferred from  these expe-
riments.  See  iron
   Sir H.  Davy  found, that more than three
parts  of potassium were  required to de-
compose one  part of  silica.   Hence we
might infer, that 100 parts of silica contain
about 60 of oxygen. In this case, the prime
equivalent of silicon, or silicium, would be
1.5, and that of silica  2.5; but  httle confi- 
SIL                                    SIL
dence can at present  be reposed in such
deductions.
  " When iron,"  says  Sir H.  Davy, *' is
negatively electrified,  and fused  by the
voltaic battery in contact with  hydrate  of
silica, the metalline globule procured con-
tains a matter which  affords silex during
its solution;  and when potassium is brought
in contact with silica ignited to whiteness,
a compound is formed, consisting of silica
and potassa; and black particles, not unlike
plumbago, are found diffused through the
compound.   From some  experiments  I
made, I am  inclined to  believe, that these
particles are conductors of electricity; they
have little action upon water, unless it con-
tain acid, when they slowly dissolve in it
with effervescence; they burn when strong-
ly heated,  and  become converted into a
white substance,  having the characters  of
silica; so that there can be little doubt, both
from analysis and synthesis, of the nature
of silica."   Elements, p. 363.
  I have already mentioned in  treating of
earths,  that Mr. Smithson had ingeniously
suggested, that silica might  be viewed in
many mineral  compounds as  acting the
part of  an acid.   This however is a  vague
analogy,  and cannot justify us in ranking
silica with acid bodies.
  When  obtained by the process first de-
scribed; it is a white powder, whose finest
particles have a harsh and gritty feel.   Its
sp. gr. is 2.66.  It is fusible only by the hy-
droxygen blow-pipe.  The  saline menstru-
um, formed by  neutralizing its alkaline so-
lution with an acid, is capable of holding it
dissolved, though silica  seems by experi-
ment to be insoluble in water.   Yet in the
water  of the Geyser  spring, a portion of
silica seems to remain  dissolved, though
the quantity of alkali present appears in-
adequate to the effect  Silica exists nearly
pure in transparent quartz  or rock crystal.
It forms  also the chief constituent of flints.
By  leaving  a solution of silica in fluoric
acid, or in aqueous  potash,  undisturbed
for a long time, crystals of this earth have
been  obtained.  The solution in  alkaline
lixivia is called liquor silicum.  Glass is  a
compound of a  similar nature, in which the
proportion of silica is much greater.
  Mr. Kirwan made many  experiments on
the mutual actions of silica and the  other
earths, at high degrees of heat.  The fol-
lowing are some of his results:
Proportions.
80 silica,  ">
20 barytes, 5
75 silica,
J
25 barytes
66 silica,   ")
33 barytes, 3
50 silica,   ")
50 barytes, 3
20 silica,   7
80 barytes, 3
25 silica,   ">
75 barytes, 3
33 silica,   5
66 barytes, 3
Heat.

150° Wedg.

150

150

148

148

150

150
        Effects.

A white brittle mass.

A brittle hard mass, semi-transparent at the edges.

Melted into a hard somewhat porous porcelain.

A hard mass, not melted.
The edges were melted into  a  pale greenish mat-
  ter, between a porcelain and enamel.
Melted into a somewhat porous  porcelain mass.

Melted  into a yellowish and  partly greenish white
  porous porcelain.
  When the barytes exceeds the  silica in
the proportion of three to one, the fused
mass is soluble in acids,—a circumstance
recently applied with  great advantage in
the analysis of minerals which contain al-
kaline matter.
  The habitudes of strontian with silica are
nearly the same as those of barytes.  Lime-
water added to the liquor silicum, occasions
a precipitate, which is a compound of the
two earths.  The following are -Mr.  Kir-
wan's results in the dry way:—
Proportions.

 50 lime,  ?
 50 silica, C
 80 lime,  7
 20 silica, 3
 20 lime,  }
 80 silica, 3
 Heat.                  Effects.
             Melted into a mass of a white colour,  semi-transparent
150° Wedg.   at the edges, and striking fire, though feebly, with steel:
              it was intermediate between porcelain  and enamel.

156
156
A yellowish-white loose powder.

Not melted: formed a brittle mass.
  When exposed  to the highest possible
heat, magnesia and silica, in equal parts,
melt into a white enamel.
  Silica and alumina unite  both in the  li-
quid and dry way.  The latter compound
constitutes porcelain and pottery-ware.
  Equal parts of lime, magnesia, and sili-
ca, melt, according to Achard, into a green 
SIL                                    SIL
 ish-coloured glass, hard enough  to  strike
 fire with steel.   When the  magnesia ex-
 ceeds either of the other two ingredients,
 the mixture is  infusible; when the silica
 exceeds, the only fusible proportions were,
 3 silica, 2 lime, 1 magnesia; and when the
 lime is in excess, the mixture usually melts
 in a strong  heat.  With mixtures of lime,
 alumina, and silica, a fusible compound  is
 usually obtained when  the lime  predomi-
 nates.   The only refractory proportions
 were,
          Lime,        2      3
          Silica,        1       1
          Alumina,     2       2
   Excess of silica gives a glass or porce-
 lain, but excess of alumina will not furnish
 a glass.
   When  in  mixtures of magnesia,  silica,
 and alumina, the first is in excess, no fu-
 sion takes place at 150*; when  the second
 exceeds, a porcelain may be formed, and 3
 parts of silica, 2 magnesia, and 1 alumina,
 form a glass.  From Achard's experiments
 it would appear, that a  glass may be pro-
 duced by exposing to a strong heat,  equal
 parts of alumina, silica,  lime, and mag-
 nesia.
   Other proportions gave fusible mixtures,
 provided the silica was  in excess.
   The mineral sommite, or nephelin, con-
 sists, according to Vauquelin, of 49 alumi-
 na + 46 silica.   If we  suppose it to con-
 sist ofa prime equivalent or  atom of each
 constituent, then that of silica would be 3;
 for 49  : 3.2 :: 46 :3.   But if we  take Vau-
 quelin's analysis of euclase for the  same
 purpose,  we have the proportion of silica
 to that of alumina as 35 to 22.   Hence, 22
 : 3.2 :: 35 : 5.09,  the prime  equivalent  of
 silica,  which is  not reconcileable to  the
 above  number, though it agrees with that
 deduced from Sir H. Davy's experiments
 on silicon.  I give these examples to show
 how unprofitable such atomical determina-
 tions are.   See  Iron,  and Acid (Fluo-
 silicic).*
   Silk.  See Bleaching.
   Silvan.   Tellurium; so called by Wer-
 ner.
   Silver is the whitest of all metals, con-
 siderably harder than  gold, very ductile
 and  malleable,  but less malleable  than
 gold; for the continuity  of its parts begins
to break  when  it  is hammered out into
leaves  of about the hundred  and sixty
thousandth of an inch thick, which is more
than one-third thicker  than  gold leaf;  in
this  state  it does not transmit  the  light.
Its specific gravity is from 10.4 to 10.5.  It
ignites before  melting, and requires  a
strong heat  to fuse  it.   The  heat of com-
mon furnaces is  insufficient to  oxidize  it;
but the heat of the most powerful burning
lenses  vitrifies a portion of it, and causes
it to emit fumes; which, when received on
a plate of gold, are found to be  silver in
the metallic state.  It has  likewise  been
partly oxidized by  twenty successive ex-
posures  to the heat of the  porcelain  fur-
nace at Sevres.  By passing a strong elec-
trie shock through a silver wire, it may
be converted into a black oxide; and  by a
powerful galvanic battery, silver  leaf may
he  made to burn with a beautiful  green
light.  Lavoisier oxidized it by the  blow.
pipe and oxygen gas; and a fine silver wire
burns in the kindled united stream of oxy-
gen and hydrogen  gases.  The air alters
it very little, though it is disposed to ob-
tain a thin purple or black coating  from
the sulphurous vapours, which  are emitted
from animal substances,  drains, or putre-
fying matters.  This coating, after a long
series   of  years,   has  been observed to
scale off from images of silver exposed in
churches; and was found, on  examination,
to consist of silver united with sulphur.
  * There seems to be only 1 oxide of sil-
ver, which is formed either by intense igni-
tion in  an open  vessel,  when  an olive-co-
loured glass is obtained;  or by adding a so-
lution of caustic barytes to one of nitrate of
silver, and heating the precipitate to dull
redness.  Sir  H.  Davy found that 100 of
silver combine with 7.3  of oxygen in the
above oxide; and if we suppose it to consist
of a prime equivalent of each constituent,
we  shall have 13.7 for the prime of silver.
Silver leaf  burned by a voltaic battery, af-
fords the same olive-coloured oxide.
  Silver combines with chlorine, when the
metal is heated in contact with  the gas.
This chloride is, however, usually prepared
by adding muriatic acid  or  a  muriate, to
nitrate of silver.  It has been long known
by the name of luna-eornea or horn-silver,
because though a white powder, as it falls
down from the nitrate solution, it fuses at
a moderate heat,  and forms a horny  look-
ing substance when it cools.  It consists of
13.7 silver -f- 4.5 chlorine.
  The sulphuret of silver is a brittle sub-
stance, of a black colour and metallic lus-
tre.  It is  formed  by  heating  to redness
thin plates of silver stratified with sulphur.
It consists of 13.7 silver  + 2 sulphur.
  Fulminating silver is formed by pouring
lime-water into the pure nitrate, and filter-
ing, washing the precipitate, and  then di-
gesting on it liquid ammonia in a little open
capsule.  In 12 hours, the ammonia  must
be cautiously decanted from the black pow-
der, which is  to  be dried in  minute por-
tions, and with extreme circumspection, on
bits of filtering paper or card.  If struck,
in even  its  moist  state, with  a hard body,
it explodes; and if in  any quantity, when
dry, the  fulmination is tremendous.  The
decanted ammonia, on being gently heated,
effervesces, from disengagement of azote,
and small  crystals appear  in  it  when it 
SIL
SIL
cools.  These possess a still more formi-
dable power of detonation, and can scarce-
ly bear touching,  even under  the liquid.
It seems to be a compound either of oxide
of silver  and ammonia, or ofthe oxide and
azote.  The latter  is probably its true con-
stitution, like the explosive  iodide  and
chloride.  The sudden extrication of the
condensed gas, is  the cause of the detona-
tion.
  In the 8th number  of the  Journal of
Science,  Mr. Farraday has described  some
experiments which seem to show that there
is a protoxide of  silver containing  about
two-thirds the quantity of oxygen found in
the common oxide,  by precipitation  from
the nitrate.   He procures it  by leaving an
ammoniacal solution of oxide of silver ex-
posed to the air.   A succession of brilliant
pellicles is obtained, which are the protox-
ide.   Experiments of this nature must be
made  cautiously, lest  fulminating  com-
pounds should accidentally be produced.*
   Silver is  soluble in  the sulphuric acid
When  concentrated  and  boiling, and the
metal  in a state of division.
   The muriatic acid does not  act upon it,
but the  nitric acid, if somewhat diluted,
dissolves it with great rapidity,  and with
a plentiful disengagement of nitrous gas;
which, during its  extrication, gives a blue
or green colour  to the acid, that entirely
disappears if the silver made  use  of be
pure.  If it contain copper, the solution re-
mains  greenish; and if the acid contain
either sulphuric or  muriatic  acid, these
combine with  a  portion of the silver, and
form  scarcely soluble  compounds, which
fall to the bottom.   If the silver contain
gold, this metal separates in blackish-co-
loured flocks.
   The nitric acid  dissolves more than half
its weight of silver;  and the solution is
very caustic, that is to say, it destroys and
corrodes animal  substances very power-
fully.
   The solution of silver, when fully satu-
rated,  deposites thin crystals  as it C00I9,
and also by evaporation.  These are called
lunar nitre, or nitrate of silver.   A gentle
heat is sufficient  to fuse them,  and  drive
off their water of crystallization.  In this
situation, the nitrate, or rather sub-nitrate,
for the heat drives off part of the acid, is
of a black colour, may be cast into  small
sticks  in a mould, and then forms the lapis
infernalis, or lunar caustic used in surgery.
 A stronger heat decomposes nitrate of sil-
ver, the acid flying off, and the silver re-
maining pure.   It is obvious that, for the
purpose of forming the lunar caustic, it is
not necessary to suffer the salt to crystal-
lize, but that it may be made  by evapora-
ting the solution  of silver at once to dry-
ness; and as soon  as the salt is fused, and
ceases to boil, it may be poured out.  The
nitric acid driven off from nitrate of silver
is decomposed, the products being oxygen
and nitrogen.
  The sulphate of silver, which is formed
by pouring  sulphuric acid into the  nitric
solution  of  silver, is sparingly  soluble in
water; and on this account forms crystals,
which are so  small, that they compose a
white powder.  The  muriatic acid precipi-
tates from nitric acid the saline compound
called lunacornea, or  horn-silver;  which
has been so distinguished, because, when
melted  and cooled,  it forms a semi-trans-
parent and partly flexible mass, resembling
horn.  It is  supposed that a preparation of
this kind has given rise to the accounts of
malleable glass.  This effect takes  place
with  aqua regia, which acts strongly on
silver, but  precipitates it in the form of
muriate, as  fast as it is dissolved.
  If any salt with base of alkali, contain-
ing the muriatic acid,  be added to the ni-
tric solution of silver, the same effect takes
place by double affinity; the  alkaline base
uniting with the nitric acid, and the silver
falling down in combination  with the mu-
riatic acid.
  Since the muriatic acid throws down only
silver, lead, and mercury, and the two latter
of these are not present in silver that has
passed cupellation, though a  small  quan-
tity of copper may elude the scorification
in that process,  the silver which may be
revived from its muriate is purer than can
readily be obtained  by any  other means.
When the salt is exposed to a low red
heat, its acid is not expelled; and a greater
heat causes the whole  concrete either to
rise in fumes, or to pass through the pores
of the vessel.  To reduce  it,  therefore, it
is necessary that it should  be triturated
with its own weight of fixed  alkali,  and a
little water, and the whole afterwards ex-
posed to heat in a crucible, the bottom of
which is covered with soda;  the mass of
muriate  of  silver being likewise covered
with the same  substance.   In  this way the
acid  will be  separated from the   silver,
which is reduced to  its metallic state.
  As the precipitate of muriate of silver is
very perceptible, the nitric solution  of sil-
ver is used as a test  of the presence of mu-
riatic acid in waters; for a drop of the  so-
lution poured into such waters will cause a
very evident cloudiness.   The solution of
silver is also used by assayers to purify the
nitric acid from any  admixture of muriatic
acid.  In this state they call it precipitated
aquafortis.
  M. Chenevix found, that a chlorate of
silver may be formed, by passing a current
of chlorine through  water  in  which  oxide
of silver is suspended; or by digesting phos-
phate of silver with hyperoxymuriate of
alumina.  It requires only two parts  of hot
water for its solution, and this affords, on 
SIL
SIL
cooling,  small white, opaque, rhomboidal
crystals.   It is likewise somewhat soluble
in alcohol.  Half a grain, mixedwith half
as much sulphur, and  struck  or rubbed,
detonates with a loud report and a vivid
flash.
  Compounds of silver with other acids are
best formed by precipitation  from its solu-
tion  in nitric acid; either by the acid itself,
or by its alkaline salts.   Phosphate of sil-
ver is a dense white precipitate,  insoluble
in water, but  soluble in an  excess  of its
acid.  By heat it  fuses  into  a  greenish
opaque glass.  Carbonate of silver  is a white
insoluble powder, which  is blackened  by
light.  The fluate and borate are equally in-
soluble.  Distilled vinegar readily  dissolves
the oxide of silver, and the solution affords
long white needles, easily crystallized.
  The precipitates  of silver, which  are
formed by the addition of alkalis or earths,
are all reducible by mere heat, without the
addition of any combustible substance.
  A detonating  powder has  been  sold
lately at Paris as an object of amusement.
It is enclosed between the folds of a card,
cut in two lengthwise; the powder  being
placed at one  end,  and the other  being
notched, that it may be distinguished.  If
it be taken  by the  notched end, and the
other be held over the  flame of a candle,
it soon detonates, with a sharp  sound, and
violent flame. The card is torn, and changed
brown; and  the part in contact  with  the
composition is covered  with a slight me-
tallic coating, of a grayish-white  colour.
  This compound, which M.Descotills calls
detonating silver, to distinguish it from the
fulminating  silver of M. Berthollet, may be
made by  dissolving silver  in  pure  nitric
acid, and pouring into the solution,  while
it is going on, a sufficient quantity of rec-
tified alcohol: or by adding alcohol to a ni-
tric  solution of  silver  with considerable
excess of acid.
  In the first case, the nitric acid, into which
the silver is put, must  be heated gently,
till the solution commences, that is, till the
first bubbles begin to appear.   It is then to
be removed from the fire, and a  sufficient
quantity of alcohol to be  added immedi-
ately, to prevent the evolution of any  ni-
trous vapours.  The mixture of the two li-
quors occasions an extrication  of heat; the
effervescence quickly recommences, with-
out any nitrous gas being disengaged; and
it gradually increases, emitting at the same
time a strong smell  of nitric ether.   In a
short time the liquor becomes  turbid,  and
a very heavy, white,  crystalline powder
falls down, which must be separated, when
it ceases to increase, and washed several
times with small quantities of  water.
   If a very acid solution of silver previously
made be employed, it must be heated gent-
ly, and the alcohol then added.  The heat
exdted by the mixture, which is to be made
gradually,  soon  occasions  a considerable
ebullition, and the powder immediately pre-
cipitates.
  It would be superfluous to  remind  the
chemist, that the mixture of alcohol with
hot nitric acid is liable  to  occasion acci-
dents, and that it is consequently prudent
to operate on small quantities.
  This powder has the following properties:
It is white and crystalline; but the size and
lustre ofthe  crystals are variable.  I.idit
alters it a little.   Heat, a blow,  or long con-
tinued friction, causes it to inflame with a
brisk detonation.   Pressure  alone, if it be
not very powerful, has no effect on it.  It
likewise detonates by the electric spark.
It is slightly soluble in water. It has a very
strong metallic taste.
  Concentrated  sulphuric acid occasions
it to take fire, and is thrown by it to a con-
siderable distance.  Dilute sulphuric acid
appears to decompose it slowly.

Process for separating silver from copper,
              by Mr. Keir.
  Put the  pieces of plated metal into  an
earthen glazed pan; pour upon them some
acid liquor, which may  be in the propor-
tion of eight or  ten  pounds of sulphuric
acid to one pound of nitre; stir them about,
that the surfaces  may  be  frequently ex-
posed to fresh liquor, and assist the action
by a gentle heat from 100° to 200° of Fah-
renheit's scale.  When the liquor is nearly
saturated, the silver is  to  be precipitated
from it by common salt, which forms a  mu-
riate of silver, easily reducible by melting
it in a crucible with a sufficient quantity
of potash; and lastly, by refining the melted
silver if necessary, with a little nitre thrown
upon it.  In  this manner the silver will be
obtained sufficiently pure,  and  the copper
will  remain  unchanged.  Otherwise,  the
silver may be precipitated in  its metallic
state, by adding to the solution of silver a
few of the pieces of copper, and a sufficient
quantity of water to enable the liquor to act
upon the copper.
   Mr. Andrew Thomson, of Banchory, has
recommended the following method of pu-
rifying silver, which he observes is equally
applicable to gold.  The impure  silver is
to be flatted out to the thinness of a shil-
ling, coiled up spirally, and  put into a cru-
cible, the bottom of which is covered with
black oxide  of manganese.  More of this
oxide is then to be added, till the silver is
completely covered, and all  the spaces be-
tween the  coils  filled.  A cover is then to
be luted on,  with a small hole  for the es-
cape of the gas; and after it has been ex-
posed to a heat sufficient to melt silver for
about a quarter of an hour, the  whole of
the alloy will be oxi-lized.   The  contents
of this crucible  are then to be  poured into 
SIL"
SIL
  a larger, into which about three times as
  much powdered green glass has been pre-
  viously put; a cover luted on as before, to
  prevent the access of any inflammable mat-
  ter; and the crucible exposed to a heat suffi-
  ciently strong to melt the glass very fluid.
  On cooling and breaking the crucible, the
  silver will be found reduced at the bottom,
  andperfectly pure.
    f A piece of silver coin, being dissolved
  in nitric acid, and left upon a warm stove,
  crystals were found in the  vessel  on  the
  next morning.   These, when  dissolved in
  pure water, formed  a  colourless solution,
  and gave no trace of copper on adding li-
  quid ammonia.  I infer, that crystallization
  may prove an eligible  mode of procuring
  a pure nitrate, and of course lunar  caustic
  or pure silver.f
    Sulphur combines very easily with silver,
  if thin plates, imbedded in it, be exposed
  to a heat sufficient  to melt the sulphur.
  The sulphuret is of a  deep violet  colour,
  approaching to black, with a degree of me-
  tallic lustre, opaque, brittle, and soft.  It
  is more fusible than silver, and this in pro-
  portion to the quantity of sulphur combined
  with it.  A strong heat expels part of the
  sulphur.
   Sulphuretted  hydrogen  soon tarnishes
  the surface of polished silver, and forms on
 it a thin layer of sulphuret.
   The alkaline sulphurets combine with it
 by heat, and form a  compound soluble in
 water.  Acids precipitate sulphuret of sil-
 ver from this solution.
   Phosphorus, left in a nitric  solution of
 silver, becomes covered with the metal in
 a dendritic form.  By boiling, this becomes
 first white, then a light black mass,  and is
 ultimately  converted into  a light  brown
 phosphuret. The best method of forming
 a phosphuret of silver is Pelletier's, which
 consists in  mixing   phosphoric  acid  and
 charcoal with the metal, and exposing the
 mixture to heat.
   Most metallic substances precipitate sil-
 ver in the metallic state from its solution.
 The assayers make use of copper to sepa-
 rate the silver from the nitric acid used in
 the process  of parting.  The  precipitate
 of silver by mercury  is  very slow, and pro-
 duces a peculiar symmetrical arrangement,
 called the tree of Diana.  In this, as in all
 precipitations, the peculiar  form may be
 affected by  a variety of concomitant cir-
 cumstances; for which reason one process
 usually succeeds better  than another.
  Make an amalgam,  without heat, of four
 drachms of leaf silver with two drachms
 of mercury.  Dissolve the amalgam in four
 ounces, or a sufficient quantity of pure ni-
tric  acid  of a moderate strength;  dilute
this solution in about a  pound and a half
of distilled water; agitate the mixture, and
  Vol.  H.
  preserve it for use in a glass bottle with a
  ground  stopper.  When  this preparation
  is to be  used, the quantity of one ounce is
  put into a phial, and the size of a pea  of
  amalgam of gold, or silver,  as soft as but-
  ter, is to be added; after which the vessel
  must be left at rest. Soon afterwards small
  filaments appear  to  issue out of the ball
  of  amalgam, which quickly increase, and
  shoot out branches in the form of shrubs.
   Silver unites with gold by fusion, and
  forms a pale alloy, as has been already men-
  tioned in treating of that metal.  With pla-
  tina it forms a hard  mixture, rather yel-
  lower than silver itself, and  of difficult fu-
  sion.  The two metals do not unite well.
  Silver melted with one-tenth part of crude
  platina, from which the ferruginous parti-
  cles had been separated by a strong mag.
  net, could not be rendered clear of sca-
  brous parts,  though  it  was  repeatedly
  fused, poured out, and laminated between
  rollers.  It was  then  fused, and suffered
  to cool in the  crucible, but with no better
  success.   After  it  had been formed,  by
  rolling and hammering, into a spoon for
  blow-pipe experiments, it was exposed to
  a low red  heat, and  became rough, and
  blistered  over  its  whole  surface.  The
  quantities were one hundred grains of sil-
  ver, and  ten grains of platina.   Nitre  was
  added during the fusions.
   Silver  very readily  combines  with mer-
  cury.  A very sensible degree of heat is
  produced,  when  silver leaf and mercury
  are  kneaded together  in the palm of the
 hand. With lead it forms a soft mass, less
 sonorous than pure silver. With copper it
 becomes harder and more sonorous, at the
 same time that it remains sufficiently due
 tile:  this  mixture is used in the  British
 coinage.  12^ parts of silver, alloyed with
 one  of copper, form the compound called
 standard  silver. The mixture of silver and
 iron has been little examined. With tin it
 forms acompound, which, like that  of gold
 with the same  metal,  has been said to be
 brittle, however  small the proportion;
 though there  is probably as little founda-
 tion  for the assertion in the one case as in
 the  other.  With bismuth, arsenic, zinc,
 and  antimony, it forms brittle compounds.
 It does not unite with nickel.   The com-
 pound of  silver and tungsten, in the pro-
 portion of two of the former to one of the
 latter, was  extended under  the  hammer
 during a few strokes; but afterwards split
 in pieces.   See Iron.
  The uses  of silver are well  known : it is
 chiefly applied  to  the forming of various
 utensils for  domestic  use, and as the me-
dium of exchange in  money.  Its disposi-
tion to assume a black  colour by tarnish-
ing, and its softness, appear to be the chief
objection to  its use in  the construction of 
SIL
SKO
graduated instruments for astronomical and
other  purposes,  in  which a good white
metal  would be  a desirable  acquisition.
The nitrate of silver, besides its great use
as a caustic, has been employed as a medi-
cine, it is  said with good success, in epi-
leptic cases, in the dose of l-20th of a grain,
gradually increased  to l-8th, three times
a-day.  Dr. Cappe  gave it in a dose of l-4lh
of a grain three times a-day, and  afterward
four times, in what he supposed to be a case
of angina pectoris, in a stout man of sixty,
whom he cured.  He took it for three  or
four months.   Dr. Cappe imagines, that it
has  the  effect  of increasing the nervous
power, by  which  muscular action is ex-
cited.
  • The  frequent employment in chemical
researches of nitrate of silver as  a reagent
for combined chlorine, occasions the  pro-
duction of a considerable quantity of the
chloride  (muriate) of silver, which is  usu-
ally reconverted into metal by fusion  with
potash in a crucible.  But, as much of the
silver is lost in  this way,  it is better to ex-
pose the  following mixture to the requisite
heat:
     Chloride of silver,           100
     Dry  quicklime,               19.8
     Powdered  charcoal,            4.2
  An easier method, however, is to put the
metallic  chloride  into a pot of clean iron or
zinc, to cover it  with  a  small quantity  of
water, and to add a little sulphuric or mu-
riatic acid.  The reduction ofthe chloride
of silver by the zinc or iron, is an operation
which it is curious  to observe,  especially
with the  chloride in mass  (luna cornea).  It
begins first at the points of contact, and
speedily extends in the  form of ramifica-
tions,  over its  whole surface, and into its
interior. Hence, in less than an hour, con-
siderable pieces of horn silver are entirely
reduced.  If the mass operated  on be con-
siderable, the temperature rises, and  acce-
lerates the revivification.  On  the small
scale artificial heat may be applied.*—Ann.
de Chimie,  July 1820.
   Silvering. There are various methods
of giving a covering of silver or  silvery as-
pect to the surfaces of bodies.   The appli-
cation of silver leaf is made in the  same
way as that of gold, for which  see Gild-
 ing.
   Copper  may be silvered over by rubbing
it with the following powder : Two drachms
of tartar,  the  same quantity of common
 salt, and half a drachm of alum, are mixed
with fifteen or twenty grains of silver pre-
cipitated from nitric acid by copper.  The
 surface  ofthe  copper becomes white  when
 rubbed with this powder, which may after-
 ward  be brushed off and polished with  lea-
 ther.
   The saddlers  and harness-makers  cover
 their wares with tin for ordinarv uses;  but
a cheap silvering  is used for this purpose
as follows : Half an ounce of silver that has
been  precipitated from aquafortis by the
addition of copper,  common salt, and mu-
riate of ammonia, of each two ounces, and
one drachm of corrosive muriate of  mer-
cury, are triturated together, and made into
a paste with water;  with this, copper uten-
sils of every kind,  that have been preri-
ously boiled with tartar and alum, are rub-
bed, after  which they  are  made red-hot,
and then polished.   The intention of this
process appears to  be  little more than to
apply  the silver in  a state of minute divi-
sion to the clean surface of the copper, and
afterward to fix it there by fusion; and ac-
cordingly this silvering may be effected by
using the argentine precipitate  here  men-
tioned, with borax or mercury, and causing
it to adhere by fusion.
   The dial-plates of clocks, the scales  of
barometers, and  other similar articles are
silvered by rubbing upon them a mixture of
muriate of silver, sea salt,  and tartar, and
afterward carefully  washing off the saline
matter with water.   In this operation, the
silver  is precipitated from the  muriatic
acid, which unites  with part of the cop-
  Eery surface.   It is not durable, but may
  e improved  by heating the article, and
repeating the  operation till the covering
seems sufficiently thick.
   The silvering of  pins is effected by boil.
ing them with tin filings and tartar.
   Hollow mirrors or globes are silvered by
an amalgam consisting of one part by weight
of bismuth, half a  part of  lead, the  same
quantity of pure tin, and two parts mer-
cury.  The solid metals are to be first fu-
sed together, and the mercury added when
the mixture is almost cold.  A very gentle
heat is sufficient to fuse this amalgam.  In
this state  it is poured into a clean glass
globe intended to be silvered, by means of
a paper funnel which  reaches to the bot-
tom. At a certain temperature it will stick
to the glass, which  by a proper motion may
thus be silvered completely, and the  su-
perfluous  amalgam  poured out.  The  ap-
pearance of these  toys is  varied by  using
glass of different colours,  such  as yellow,
blue,  or green.
   * Skorodite. Colour leek-green. Mas-
 sive, but generally crystallized in very short
 broad rectangular four-sided prisms.  Frac-
 ture uneven.  Translucent.  As hard  as
 calcareous spar. Easily frangible. It melt!
 before the blow-pipe, with emission  of ar-
 senical vapour, and is converted into  a red-
 dish-brown mass, which, when highly heat-
 ed, so as to drive  off" all the arsenic, be-
 comes attracted by the magnet. It is an ar-
 seniate of iron, without copper.  It occurs
 in quartz and hornstone, in primitive rocks,
 in the Schneeberg mining district in Saxo-
 nv.* 
SOA
SOA
  * Slats (Adhesive).  See Clay.*
  * Slate Clay.  See Clay.*
  • Slate Coal.  See Coal.*
  • Slate Spar, or Schiefer Spar. A
sub-species of limestone.*
  • Slick ens ides. The specular variety
of Galena, so called in  Derbyshire.  It ex-
presses  the smoothness of its surface.  It
occurs lining the walls of very narrow rents.
It has a most  remarkable  property, that
when the rock in which it is contained is
struck with a hammer,  a crackling noise is
heard, which is generally followed by an
explosion ofthe rock, in the direction and
neighbourhood of the vein.  The cause of
this singular effect has  not been satisfacto-
rily explained.—Jameson*
  Smalt.  See Zaffre.
  • Smaragdite.  Diallage.*
  Smaragdus.   See Emerald.
  Soap.  Macquer gives us the following
process for oil soap: One part of quicklime
and  two parts of good Spanish soda, are
boiled together during a short time, with
twelve times as much water, in an iron cal-
dron.  This lixivium is to be filtered,  and
evaporated by heat, till a phial, which is
capable of containing  an ounce of water,
shall contain  an ounce and three-eighths of
this  concentrated lixivium.   One  part of
this lixivium is to be mixed with two parts
of oil of olives, or of sweet almonds, in a
glass or stoneware vessel.  The mixture is
to be stirred from time to time  with an
iron spatula, or with a pestle, and it soon
becomes thick  and white.   The combina-
tion  is gradually completed,  and in seven
or eight days a very white and firm soap is
obtained.
  For the coarser sorts of soap, cheaper
oils are  employed, such as oil of nuts, lin-
seed, hempseed, fish, &c.  Either of these
kinds of soap, to be good, must neither feel
greasy nor Unctuous in water, nor exhibit
any vestige of fat  upon  the water. It ought
farther to dissolve easily in water, and la-
ther well, as likewise  be easily soluble in
alcohol.  It must not become moist in the
air, or throw out a saline efflorescence on
its external surface.
    For making Brown  or Yellow Soap.
  Let there be weighed 10 cwt. of tallow,
and about 3 cwt.  of resin, the resin to be
broken into small lumps. In the first place,
put into the boiler about 150 or 200 gallons
of ley, and set the fire;  then add the tallow
and resin. This done, the pan is said to be
charged.
  A good fire may be kept up until all is
thoroughly melted, and the pan brought to
boil; during which time there ought to be
constant stirring  with  the paddle, to pre-
vent the resin from  settling to the bottom.
If the goods or materials in the pan appear
to swell up, damp the  fire, which is done
by opening the furnace door, and throwing
ashes thereon,  (some have proper damp-
ers), when the  whole will boil at leisure.
As  the  caustic  alkali immediately unites
to the tallow, there is no occasion for long
boiling; about two or three hours will be
long enough. The fire may then be drawn,
and the pan allowed to stand for four or
six hours, when the weak ley may be pump-
ed off, and fresh added for a second boil.
It may be necessary to mention, that when
the pan is wished to be cranned, or pump-
ed off sooner, a few pails of cold ley must
be thrown in, a  little after the fire is drawn.
  Set the fire again for the second boil, and
when properly  a-boil, two or  three hours
may be  sufficient at any one time to conti-
nue the boil. The  strength of the ley is
often gone before this  period arrives.   A
short experience, however, with attention,
will perfectly inform any sagacious person
with regard  to this particular.
  The boilings  to be thus continued day
after day, until the soap becomes thick, and
ofa strong consistence.  Take then a little
upon the forefinger, and after letting it cool
a few seconds, press it  with the thumb  If
it squeeze into  a thin hard scale, the soap
is fit or ready for finishing: if otherwise it
appear greasy,  and stick to the finger, and
of a soft consistence, more ley must be add-
ed; and if this does not harden it, another
boil must be given.  But, in consequence
of the former  scaly appearance, give the
pan a good hearty boil, and draw the fire.
Cool down with two or three pails of ley,
and in about two hours thereafter pump off
the ley; which  should be done at all times
as clean as possible.  This done, put in six
or eight pails of water to the boiler,  (no
ley at finishing being  used), set a brisk
fire, and keep constantly stirring with hand-
stirrer and paddle alternately, until all is
melted, and begins to show an appearance
something like  thin  honey.  Take now  a
little  from a boiling  part upon  the hand-
board, and observe,  when held up,  if any
ley runs clearly from  it  If it do, more
water must  be  put  in, and the boil conti-
nued.   When, upon the other hand, no ley
runs from the soap when held up slanting-
ways upon the board, in this case  too much
water has already  been  given.   A little
strong solution  of salt must now  be added.
to open it, technically termed cutting up; or,
instead of salt brine, alittle strong common
salt and water;  about half a pailful may do.
We come now  to the most critical part of
boiling, that is, the finishing of  the soap:
and it ought to  be particularly attended to,
that the soap be brought to such a state,
as, when held up upon  the hand-board, the
ley does not run down  from the  soap,  but
is seen, as it were,  just starting from it.
The fire may then be drawn away, and the
soap  declared  finished; or if palm-oil be
wished  for making it of a beautiful colour, 
SOA                                  SOA
about 201bs. may be put into the boiler, af-
ter you discover, as above, the soap to be
finished; and in about  half an hour after
the oil is put in, the fire may be drawn, and
the whole allowed to stand for forty-eight
hours, when it mav be cast into the frames.
  In  about  three  days,  (supposing the
frames  30 inches deep),  the  whole  will
cut up into bars.
     A Charge for pure White Soap.
  The boiler being made  perfectly clean,
put in  10 cwt. of best home melted tallow,
(no resin is  used  in white soap),  with 200
gallons of ley; melt down with a moderate
fire, as  the goods now in  hand are some-
thing similar to milk, exceeding apt to boil
over.
  Close attention, therefore, is absolutely
needful upon this first boil;  which may be
continued about two hours, with a mode-
rate fire, when it may be drawn away, and
the pan allowed to  settle about two hours,
when the ley may be drawn off.  The pro-
cess to be observed in  this soap is exactly
similar to the last operation. Two or three
boils  a day to white  soap  may be given
with great ease; the ley sooner  subsiding
in the boiler than  with yellow soap, and
can be cleaner pumped off.
  When sufficient  boils have been given,
and the soap  is arrived at perfection, it
will assume an appearance something like
a curdy mass.  Take  then a little upon
your fore-finger, (as before directed), and
if the same effect seem to attend it, that
is, when pressed with the thumb it squeeze
into a thin, hard, clear scale, and part free-
ly from the finger, the  soap is  ready for fi-
nishing.  Draw the fire, cool down with a
few pails of ley, and in a short time there-
after pump clean off.
   Set  the fire, and add to the soap eight
or ten pails of water, (the pail I  suppose
to contain about  nine  or ten English gal-
lons).   When this is melted, and properly
incorporated with the soap, try, as former-
ly directed, if the ley run from it when held
up upon the hand-board.   If it  do, more
water must be put in.  If it do not run, or
there be no appearance of it, continue boil-
ing for a short while longer, and then add
a pail of salt and water pretty strong, mix-
ed together; about one-third salt, and two-
thirds water.   This will have  the effect of
cutting up the pan, or  separating the soap
and water completely from one  another.
When this is apparent, draw the fire; let it
stand for half an  hour, when the water will
pump off, bringing therewith most of the
remaining alkaline  ley of the former boil.
   This I call the first washing; and if kelp
ley has been used in the operation, the pro-
priety of this must  be  conspicuous; for the
water pumped off' will be of an  exceeding
dark bottle-green »;olofrr.  The finishing of
white soup without Hhi*precaution, is the
sole  causr of the bluencss,  so frequently
observed in this article when  made  and
brought to market.
  The blue ley being pumped clean off, set
again the fire, and put into  the boiler six
or eight pails of water;  and when  tho-
roughly  incorporated and  boiled some
time, try if the water run from the soap.
If it do, add water in small  quantities at a
time, until it is  observed not to run,  but,
as formerly mentioned for yellow soap, to
appear as just starting from the soap.  In
this  case  after giving a  good  boil,  and
swelling the soap up in the pan to near the
brim, draw away all the fire, and spread it
about to die away.  The pan is now finish-
ed, and may stand about twelve or fourteen
hours; and if the quantity be large, that is,
two, three, or four ton, double this time to
stand will be much in favour of the soap,
providing always, that it can be kept very
close and warm in the boiler.  If any blue-
ness still appear, repeat the washing.
  Before casting, I would recommend the
frames  to  have a  bottom  and lining of
coarse cloth, for white soap only. After
all is cast into the frames,  let it  be  well
stirred, or crutched; and it is very proper,
that  it also be covered close up with old
sheets, bass matts, &c. upon  the top of the
frame  and  soap, and  allowed to cool  gra-
dually, and all together.
  In about three or four days, (supposing,
as formerly, the dip 30 inches), the cover.
ings  and frames may be taken off,  and the
whole cut up into such size of bars as may
best  suit the customers.
  To give this white  soap the perfume of
what rs commonly called Windsor soap,  a
little of the essential oil of caraway seeds,
mixed with a small portion of alcohol, may
be incorporated with the soap when putting
into  the frame, stirring it in hy little  at  a
time, So as  to  diffuse it throughout the
whole mass.
  For making Black or Green Soft Soap.
  The peculiar method pursued in making
this  soap, differs considerably from that of
making hard soap. The hard has the whole
of the ley totally extracted before finish-
ing: soft soap, on' the contrary, retains the
whole of the ley used in the making; be-
coming, with the  other materials employ-
ed,  one compound body, called soft  soap.
A few examples will clearly explain the
nature and practical means  made use  of in
producing this very useful soap.
   We shall now commence an operation
with a charge for what is called
     First Crown Soft Soap,  18 Barrels.
   The quantity of ley requisite for comple-
tion of this charge will be  about  400 gal-
lons; about one-third of which must be put
into the boiler previous to any ofthe other
materials:  afterward  add, 2 cwt. 2 qrs. of
tallow, 2 cwt. 2 qrs. of hogs'-Iard, and 70 
SOA                                  SOD
gallons of olive oil.  The ley herein to be
used is supposed to be from Hungarian and
English (Essex) ashes.  The proportion is
one of the English to eight of the Hunga-
rian.   The particular mode of proceeding
is this:  After the  ley is put in, add the tal-
low, and light the fire.   When all the tal-
low is  melted, put in the oil, and draw the
fire a little afterward, and allow the pan to
stand about  two hours.   Light again the
fire, and add about 20 gallons more of the
ley. After the pan begins to boil, add now
and then a little more ley, for the purpose
of preventing the soap from boiling over;
and this adding of ley is  to be continued,
until the soap is supposed to be about half
boiled, when it will be time to try whether
the soap has got too  much or too httle ley.
   This trial is called proving, and is neces-
sary to be done  several  times  during the
operation, and previous to the finishing.
The method of performing it is this: Pro-
vide a piece of glazed Dutch delft, and also
a clear clean knife; with the knife take up
a piece of the soap from the pan, and if it
turn whitish thereon,  and fall  from it in
short pieces upon the delft, it is then to be
concluded that too much ley has been put
in; to rectify which,  a little more oil  must
be added.   On  the  contrary, if the soap
want ley, it will fall from the knife in long
ropy pieces;  in consequence of which add
some more ley.  When, however, it hap-
pens to be brought  to perfection, neither
wanting more ley nor oil, but just in a right
State, it will then be observed, when taken
upon the knife, to stand the proper colour,
not ropy, nor too white, but transparent.
The fire may now be drawn, the soap be-
ing properly finished,  and ought immedi-
ately to be cast into the barrels, firkins, &c.
   Remember always, after the second time
the fire is lighted, to keep the soap boiling
briskly, till the pan is nearly ready, when it
ought to boil slow, until  finishing, and rea-
dy to cast.
   A Charge for Second Crown Soft Soap.
    280 lbs. of tallow,
     140 gallons of ley,
    82 gallons of whale  oil.
   Put in 100 gallons of ley, with the tallow,
and light the fire.  When the tallow is
melted, add the oil, and draw the fire.  Let
all stand for two hours.   Again light the
fire, and add 20 gallons of ley.   With this
the boiling  is to be continued, until the
soap is about half finished, when  10 gallons
more of ley are to be added.  During the
remainder of the  boiling, add, at different
periods, the other 10 gallons of ley, which
will completely finish the soap.   See Fat.
   For eau de luce, Wiegleb directs, that in
two drachms of the strongest  alcohol be
dissolved from six to ten drops of rectified
oil of amber, and afterward one scruple of
white soap.:  o this mixture is  then  to be
poured an ounce of pure ammonia, and the
whole well shaken together.
  Soap-stone.  See Steatite.
  * Soda. Formerly called the mineral al-
kali, because under the name of natron it
is found native  in mineral seams or crusts.
The impure commercial  substance called
barilla is the incinerated salsola soda. Kelp,
the incinerated sea-weed, is a still coarser
article, containing seldom above 2 or 3 per
cent of real soda, while barilla occasionally
contains 20. The crystallized carbonate of
soda of commerce is procured from the de-
composition of sulphate of soda, or muriate
of soda.   The former is effected  by calci-
nation with charcoal and chalk in a rever-
beratory furnace; the latter is accomplish-
ed by the addition of carbonate of potash.
To procure pure soda, we  must boil a so-
lution of the  pure carbonate  with half its
weight of quicklime,  and after subsidence
decant the clear ley, and  evaporate  in a
clean iron  or silver vessel, till the liquid
flows  quietly like oil.  It must then be
poured out on a polished  iron plate.  It
concretes into a hard  white cake,  which is
to be  immediately broken  in pieces,  and
put  up, while still hot, in  a  phial, which
must be  well corked.  If the carbonate of
soda be somewhat impure,  then, after the
action of lime,  and subsequent concentra-
tion of the ley, alcohol must  be digested
on  it, which will dissolve only the caustic
pure soda, and leave the  heterogeneous
salts.  By distilling off the alcohol in a sil-
ver alembic, the alkali may then be obtain-
ed pure.
  This white solid substance  is, however,
not absolute soda, but a hydrate, consisting
of about 100 soda -+- 28 water; or of nearly
77 + 23, in 100.   If a piece  of this soda
be exposed to  the air, it softens and be-
comes pasty;  but it never deliquesces  into
an oily looking liquid, as potash does. The
soda in fact soon becomes  drier, because
by absorption of carbonic acid from the air
it passes  into  an  efflorescent carbonate.
Soda is distinguishable from potash by sul-
phuric acid, which forms a very soluble salt
with the former, and a sparingly  soluble
one  with the latter;  by muriate of platina
and  tartaric acid, which occasion precipi-
tates with potash salts, but not with those
of soda.
  The basis of soda  is a peculiar  metal,
called  sodium, discovered by  Sir H. Davy
in 1807,  a few days  after  he discovered
potassium. It may be procured in exactly
the same manner as potassium, by electri-
cal or chemical decomposition of the pure
hydrate.   A rather higher degree of heat,
and greater voltaic power, are required to
decompose soda than potash.   Sodium re-
sembles potassium in many of its  charac-
ters.  It  is as  white  as silver, possesses
great lustre,  antl is a good conductor  of 
                 SOD

electricity.  It enters into fusion at about
200* Fahr., and rises in vapour at a strong
red heat.  Its sp. gr. is, according to MM.
Gay-Lussac  and Thenard, 0.972, at  the
temperature of 59* Fahr.  In the cold, it
exercises  scarcely any action on  dry  air,
or oxygen.  But when heated strongly in
oxygen or chlorine, it burns with  great
brilliancy.  When thrown upon  water, it
effervesces violently, but does not inflame,
swims on the surface, gradually diminishes
with great agitation, and renders the water
a solution of soda.  It acts upon most sub-
stances in a manner similar to potassium,
but with less energy.   It tarnishes in  the
air, but more slowly; and, like potassium,
it is best preserved under naphtha.
  Sodium forms two distinct combinations
with oxygen; one is pure  soda, whose  hy-
drate is above described; the other is  the
orange oxide of sodium, observed, like the
preceding oxide, first by Sir H.  Davy in
1807, but of which the true nature was
pointed out in 1810, by MM. Gay-Lussac
and Thenard.
  Pure soda may be  formed by  burning
sodium in a quantity of air, containing no
more oxygen than is sufficient for its  con-
version into this alkali; i. e. the metal must
be in excess; a strong degree of heat must
be employed.
  Pure soda is of a gray colour; it is a non-
conductor of electricity, of a vitreous frac-
ture, and requires a strong red heat for its
fusion.  When  a little water is added to it,
there is a violent action between the two
bodies; the soda becomes white, crystalline
in its appearance, and much more fusible
and volatile. It is then the substance com-
monly called pure or caustic soda; but pro-
perly styled  the hydrate.
  The other oxide, or peroxide of sodium,
may be formed by burning sodium in oxy-
gen in excess.   It  is of a deep orange co-
lour, very fusible, and a non-conductor of
electricity.  When acted on by  water, it
gives off oxygen,  and the water becomes
a solution of soda.  It deflagrates  when
strongly heated with combustible bodies.
  The proportions of  oxygen in soda,  and
in the orange peroxide of sodium are easi-
ly learned by the action of sodium on  wa-
ter and on oxygen.  If a  given  weight of
sodium, in a little glass tube, be thrown by
means of the finger under a graduated in-
verted jar, filled with  water,  the  quantity
of hydrogen evolved will indicate the quan-
tity of oxygen combined with the metal to
form  soda;  and  when sodium  is slowly
burned in a tray of platina, (lined with dry
common salt), in oxygen  in  great excess,
from the quantity of oxygen absorbed the
composition of the peroxide may be learn-
ed. From Sir H. Davy's experiments, com-
pared with those of M M. Gay-Lussac and
Thenard, it appears that the prime  equi-
                SOD

valent of sodium  is 2.95, and that of dry
soda, or protoxide of sodium, 3.95; while
the orange oxide or deutoxide is 4.95. The
numbers given by M. Thenard are, for the
first, 100 metal -\- 33.995 oxygen; and for
the second, 100 metal -+- 67.990 oxygen.
  Another oxide  is described containing
less oxygen than soda; it is therefore a sub-
oxide.  When sodium is kept for some time
in a small quantity of moist air, or when
sodium in excess is heated with hydrate of
soda, a dark grayish substance is formed,
more inflammable than sodium; and which
affords hydrogen by its action upon water.
  Only one  combination of  sodium  and
chlorine is known.  This is the important
substance common salt.  It may be  formed
directly by combustion, or by decomposing
any compound of chlorine by sodium.  Its
properties are well known, and are already
described under  Acid  (Muriatic).  It
is a non-conductor of electricity, is fusible
at a strong red heat, is volatile at a white
heat, and crystallizes in cubes.  Sodium
has a much stronger attraction for chlorine
than for oxygen; and soda, or its hydrate,
is decomposed by chlorine,  oxygen being
expelled from the first, and  oxygen  and
water from the second.
  Potassium  has a stronger attraction for
chlorine than sodium has; and one mode of
procuring sodium easily, is by heating to-
gether to redness, common  salt and potas-
sium.  This chloride of sodium, improper-
ly called the muriate, consists of 4.5 chlo-
rine -4- 295 sodium.   There  is no known
action  between sodium  and  hydrogen or
azote.
  Sodium combines readily with sulphur
and with phosphorus, presenting  similar
phenomena to those presented by  potas-
sium.  The sulphurets and phosphurets of
sodium agree in their general properties
with those of potassium, except that they
are rather less  inflammable.   They form,
by burning,  acidulous  compounds of sul-
phuric and phosphoric acid and soda.
  Potassium  and  sodium  combine with
great  facility, and  form  peculiar  com-
pounds, which differ  in  their properties,
according to the proportions of the con-
stituents.  By a small quantity of sodium,
potassium is rendered  fluid  at  common
temperatures, and its sp. gr. is considera-
bly diminished.  Eight parts of potassium,
and one of sodium, form a compound  that
swims in naphtha, and that is fluid at the
common temperature  of the air.  Three
parts  of  sodium, and one  of potassium,
make a compound, fluid at common tempe-
ratures.  A  little potassium  destroys the
ductility of sodium, and  renders it very
brittle and soft.  Since the prime of potas-
sium is to that of sodium, as 4.95 to 2 95;
it will require the former quantity of pot-
assium, to eliminate the latter quantity of 
SOI                                    SOI
sodium from the chloride. The attractions
of potassium, for all substances that have
been examined, are stronger than those of
sodium.
  Soda is the basis of common salt, of
plate  and crown-glass, and  of  all  hard
soaps.  Elements of Chemical Phil*
  * Sodahte.  Colour green.  Massive
and crystallized  in rhomboidal dodecahe-
drons.   Shining.   Cleavage double. Frac-
ture small conchoidal.  Translucent.   As
hard as feldspar.  Brittle.  Sp. gr. 2.378.
It is infusible; becoming  only dark gray
before the blow-pipe. Its constituents are,
silica 38.5 or 36, alumina 27.48 or 32, lime
2.7 or 0, oxide of iron 1 or 0.25, soda 25.5
or 25, muriatic acid 3 or 6.75; volatile mat-
ter 2.10 or 0, loss  1.7 or 0.—Thomson and
Ekeberg.  It was discovered in W est Green-
land by Sir Charles Gieseke,  in a bed in
mica slate.*
  • Sodium.  See Soda.*
  Soil.  The soil or earth in which vege-
tables grow, varies considerably in its com-
position, or in the  proportions of the dif-
ferent earths of which it consists; and some
plants are found to thrive best in one kind
of soil, others in another.   Under Analysis
the methods of analyzing soils, so as to as-
certain their composition, will be found, as
given by Sir H. Davy; and we shall here
subjoin the rules he has laid down for their
improvement, as connected with  the prin-
ciples of which they consist.
  In cases where a barren soil is examined
with a view to its improvement, it ought in
all cases, if possible, to be compared with
an extremely fertile soil in the same neigh-
bourhood, and in  a similar situation; the
difference given by their analyses would
indicate  the  methods of cultivation, and
thus the  plan of  improvement would be
founded upon accurate scientific principles.
  If the fertile soil contained a large quan-
tity of sand, in proportion to  the barren
soil, the process of melioration would de-
pend  simply  upon a supply  of  this  sub-
stance; and the method would  be equally
simple with regard to soils deficient in clay
or calcareous matter.
  In the  application of clay,  sand, loam,
marl, or chalk to  lands, there are no par-
ticular chemical principles to be observed;
but when quicklime  is used,  great care
must be taken, that it is not obtained from
the magnesian limestone; for  in this case,
as has been shown by Mr. Tennant, it  is
exceedingly injurious to land.  The mag-
nesian limestone may be distinguished from
the common limestone by its  greater hard-
ness, and by the length of time that it re-
quires for its solution in acids; and it  may
be analyzed by the process for carbonate
of lime and magnesia.
  Wrhen the  analytical comparison indi-
cates an excess of  vegetable matter as the
cause of sterility, it may be destroyed by
much pulverization and exposure to air, by
paring and burning, or the agency of lately
made quicklime.  And the defect  of ani-
mal and vegetable matter must be supplied
by animal or vegetable manure.
  The general  indications of fertility and
barrenness, as found by chemical experi-
ments, must, necessarily differ in different
climates, and under different circumstan-
ces.   The power of soils  to  absord mois-
ture, a principle essential to  their produc-
tiveness, ought to be much greater in warm
and dry countries, than in cold  and moist
ones; and the quantity of fine  aluminous
earth they contain should be larger.  Soils
likewise  that are  situate on  declivities
ought to be more absorbent than those in
the same climate on plains or in valleys.
  The productiveness of soils must  like-
wise be influenced by the nature of the
sub-soil, or the  earthy or  stony  strata on
which they rest;  and this  circumstance
ought to  be  particularly  attended to, in
considering their chemical nature, and the
system  of improvement.  Thus a sandy
soil may owe its fertility to the  power of
the sub-soil to retain water; and an absor-
bent clayey soil may occasionally be pre-
vented from being barren, in  a  moist cli-
mate, by the influence of a substratum of
sand or gravel.
   Those soils that are most productive of
corn, contain always certain proportions of
aluminous or calcareous earth  in  a  finely
divided state, and a certain quantity of ve-
getable or animal matter.
   The quantity of calcareous earth is how-
ever  very various, and in some cases ex-
ceedingly small.  A very  fertile corn soil
from Ormiston in East Lothian afforded in
a hundred parts only eleven parts of mild
calcareous earth;  the  finely divided clay
amounted to forty-five parts.  It lost nine
in decomposed animal and vegetable mat-
ter, and four in water, and exbibited indi-
cations of a small quantity of phosphate of
lime.
   This soil was of a very fine texture, and
contained very  few stones or vegetable fi-
bres.  It  is not unlikely,  that its fertility
was  in some  measure connected with the
phosphate; for  this substance is found in
wheat, oats, and barley, and  may be a part
of their food.
   A soil from the low lands of Somerset-
shire, celebrated for producing excellent
crops of wheat and beans  without manure,
1 found to consist of one-ninth of  sand,
chiefly siliceous, and eight-ninths of calca-
reous  marl  tinged with iron, and contain-
ing about five parts in the hundred of ve-
getable matter.  1 could  not detect in  it
any phosphate or sulphate of lime, so that
its fertility must have depended  principally
upon its power of attracting principles of 
SOL                                 SPA
  vegetable nourishment from water and the
  atmosphere.
    Mr. Tillet, in some experiments made
  on the composition of soils at Paris, found,
  that a soil  composed of three-eighths of
  clay, two-eighths of river sand, and three-
  eighths of the  parings  of limestone, was
  very proper for wheat.
    In general, bulbous roots require a soil
  much more  sandy, and less absorbent, than
  the grasses.  A very good potato soil, from
  Varsel in Cornwall, afforded seven-eighths
  of siliceous sand; and its absorbent power
  was so small, that  100 parts lost only  2  by
  drying at 400° Fahrenheit.
   Plants and trees, the roots of which are
  fibrous and hard, and  capable of penetrat-
  ing deep into the earth, will vegetate  to
  advantage in almost all common soils that
  are moderately dry, and do not contain a
  very great excess of vegetable matter.
   The soil taken from a field at Sheffield-
  place in Sussex, remarkable for producing
  flourishing oaks, was  found  to  consist  of
  6 parts of sand, and  1 part of clay and
 finely divided matter.  And 100 parts of the
 entire soil submitted to analysis, produced
 water 3, silex 54, alumina 28, carbonate of
 lime 3, oxide of iron 5,  decomposing ve-
 getable matter 4, loss 3.
   From the great difference of the causes
 that influence the productiveness of lands,
 it is obvious, that in the present state of
 science, no certain system can be devised
 for their  improvement, independent of ex-
 periment; but there are few cases, in which
 the labour of analytical trials will  not be
 amply repaid by the certainty with which
 they denote the best methods of meliora-
 tion; and this will particularly happen,
 when the defect  of composition is found
 in the proportions of the primitive earths.
   In supplying animal or  vegetable  ma-
 nure, a temporary  food only is provided
 for plants, which is in all cases exhausted
 by means of a certain number of crops;
 but  when a soil is rendered of the best
 possible constitution and texture with re-
 gard to its earthy parts,  its fertility may
 be considered as permanently established.
 It becomes  capable of attracting  a very
 large portion of vegetable  nourishment
 from the atmosphere, and of producing its
 crops with comparatively little labour  and
 expense.
  Solders, and Soldering. Solders con-
 sist merely of simple or mixed metals, by
 which alone metallic bodies can  be firmly
 united with each other.   In this respect  it
 is a general  rule, that  the  solder  should
 always be easier of  fusion than the metal
 intended to be soldered by it; next  to this,
care must also be taken, that the solder
be as far as is possible  of the same colour
with the metal that  is to be soldered.
  For the  simple solders, each of the me-
 tals may be used according to the nature
 of that which is to be soldered.  For fine
 steel, copper,  and brass  work, gold and
 silver may be employed.  In the large way,
 however, iron is soldered with copper, and
 copper and brass with tin.
   The most usual solders are the compound,
 which are distinguished into two principal
 classes, viz.  hard and soft solders. The
 hard solders are ductile,  will bear ham-
 mering, and are commonly prepared of the
 same  metal  with that which is to be in!.
 dered, with the addition of some other, by
 which a greater degree of fusibility is ob-
 tained, though the addition is not always
 required to be  itself easier of fusion.  Un-
 der this head comes the harder solder for
 gold, which is  prepared from gold and sil-
 ver, or gold  and copper,  or gold, silver,
 and copper.  The hard solder for silver is
 prepared from equal parts of silver and
 brass, but made easier of fusion by the ad-
 mixture of a sixteenth part of zinc. The
 hard solder for brass is obtained from brass
 mixed with a sixth, or an  eighth, or even
 one-half of zinc, which may also be used
 for the hard solder of copper.  It  is sold
 in the shops in  a  granulated  form, under
 the name of spelter-solder.
   The soft solders melt easily, but are part-
 ly brittle, and  therefore cannot be ham-
 mered.  Of this kind are the following mix-
 tures: tin and lead in equal parts;  of still
 easier fusion is  that consisting of bismuth,
 tin, and lead, equal parts;  1 or 2 parts of
 bismuth, of tin and lead each 1 part.
   In the operation of  soldering, the sur-
 faces of the metal intended to be joined
 must be made very clean,  and applied  to
 each other.  It  is usual to  secure them by
 a ligature of  iron  wire, or other  similar
 contrivance.  The solder is laid upon the
joint, together with sal ammoniac or borax,
 or common glass, according to the  degree
 of heat intended.   These additions defend
 the metal  from oxidation.  Glaziers use
 resin; and pitch is sometimes employed.
   Tin-foil applied between the joints of
fine brass work, first wetted with a strong
solution of sal ammoniac, makes an excel-
lent juncture, care  being  taken to avoid
too much heat.
   * Solids and Solidity.   See  Calo-
ric, and Crystallization.*
  Solution.  See Salt,  Crystalliza-
tion, and Attraction.
  •Sommite.  Nepheline.*
  • Sorb at es.  Compounds of sorbic, or
malic acid, with the  salifiable bases. See
Acid (Sorbic).*
  * Sory.  The ancient name of sulphate
of iron.*
  * Spar (Fluor).  See Fluor.*
  •Spar (Ponderous).   See  Heaw-
spar.*
  * Sparry Anhydrite, or Cube-Spar" 
SPE                                  SPE
 A sub-species of prismatic  gypsum.  Co-
 lour white, passing into blue or red.  Mas-
 sive, in distinct  concretions, and  crystal-
 lized.  The primitive figure is an  oblique
 prism, in which  the angles are 108° 8' and
 79° 56'.  The secondary forms are, a rec-
 tangular four-sided  prism, a broad six-
 sided prism, an  eight-sided  prism, and a
 broad rectangular four-sided prism, acumi-
 nated.  Splendent, pearly.  Cleavage three-
 fold.  Fragments cubical.  Fracture con-
 choidal.  Transparent.  Refracts  double.
 Scratches calcareous spar, but  not  fluor.
 Brittle. Sp. gr. 2.7 to 3.0.  It does not ex-
 foliate  before  the blow-pipe, and melt like
 gypsum, but becomes glazed over with a
 white friable enamel.  Its constituents are,
 lime 41.75, sulphuric acid 55, muriate of
 soda 1.—Klaproth.   It is  sometimes met
 with in the gypsum of Nottinghamshire.
 It occurs in the salt mines of Halle, &c*
   "Sparry Iron. Carbonate of iron. Co-
 lour pale yellowish-gray.  Massive, disse-
 minated  and crystallized.  The primitive
 form is a rhomboid of 107°.  The follow-
 ing are some of the secondary forms. The
 primitive, perfect, or truncated; a still flat-
 ter rhomboid; the spherical lenticular form;
 the saddle shaped lens, and the equiangu-
 lar six-sided prism.  Glistening  or splen-
 dent, or pearly.  Cleavage threefold. Frac-
 ture foliated, or splintery.  Translucent on
 the  edges.  Streak  white  or yellowish-
 brown.  Harder than  calcareous spar.  Ea-
 sily frangible.  Sp. gr. 3.6  to 3.9  It black-
 ens and  "becomes magnetic before  the
 blow-pipe, but does not melt; it effervesces
 with  muriatic acid.  Its constituents are,
 oxide of iron 57.5, carbonic acid 36, oxide
 of manganese 3.5, lime 1.25.—Klaproth.  It
 occurs in veins in  granite, gneiss, &c. associ-
 ated with ores of lead, cobalt, silver, copper,
 &c.   But the most extensive formations of
 this mineral  are in limestone.  It is found
 in small quantities in England, Scotland,
 and Ireland; in Saxony, Bohemia, &c; and
 in large quantities in Fichtelgebirge; and
 at Schmalkalden  in Hessia.  It affords an
iron well suited for conversion into steel.—
 Jameson*
  •Specific Gravity.  The density of
the matter of which any body is composed,
 compared to the density of another body,
assumed as the standard.  This standard
is pure distilled water, at the temperature
of 60° F.  To  determine the specific gra-
vity of a solid, we weigh it, first  in air,
and then in  water. In  the latter  case  it
loses, of its weight, a quantity precisely
equal to the weight of its own bulk of wa-
ter; and hence, by comparing this  weight
with its total weight,  we find its specific
gravity.  The rule therefore is, divide the
total weight, by the loss of weight in water,
the quotient is the specific gravity.  If it
   Vol. II.
 be a liquid or a gas, we weigh it in a glass
 or other vessel of known capacity; and di-
 viding that weight,  by the weight of the
 same bulk of water, the quotient is, as be-
 fore, the specific gravity.   See Hydrome-
 ter, for another modification of the same
 rule.
   To calculate the  mean  specific gravity
 of a compound  from those of its compo-
 nents, is a problem of perpetual recurrence
 in chemistry.  It is only by a comparison
 of the result of that calculation,  with  the
 specific gravity  of the compound experi-
 mentally ascertained,  that we can disco-
 ver whether the  combination has been ac-
 companied with  expansion or condensation
 of volume.  As  several  respectable expe-
 rimental chemists  (see  Alloy  and  Am-
 monia) seem deficient in  the knowledge
 of chemical computation, I  shall here insert
 a short abstract of a paper which  I pub-
 lished on this subject in the 7th number of
 the Journal of Science.
   " The specific  gravity of one body is to
 that of another, as the weight of the first,
 divided by its volume, is to the weight of
 the second, divided by its volume; and the
 mean specific gravity of the two, is found,
 by dividing the sum of the weights by the
 sum of the volumes.
   Let W, w, be the two weights; V, v, the
 two volumes; P, p, the two specific gravi-
 ties; and M,  the  calculated mean specific
 gravity, Then
       W -J- w
 M = ■ ■   ,—;  the  formula by  which I
       V +  v
 computed the second column of Table II.
   L  A  v  .      W  ,  w    W/> + wP
   AndV+«=F-T- - =   '  vp
   Hence
 \V + w =    W+w  _ (W+w)Pj>
 V + x.    W/» + *>P    1'w+pW ~M
              vp
   When the difference in density, between
 the two substances is considerable, as it is
 with sulphuric acid and water, the  errors
 produced  by assuming  the arithmetical
 mean, for the true calculated mean, are ex-
 cessive. If we take copper and tin, however,
                            8.89 -4- 7.29
 then  the arithmetical  mean,----------

 = 8.09, differs very little  from 8.01, the
 accurate mean density.
   By a similar error, I suppose, in  calcu-
 lating the mean density of  liquid muriatic
 acid in its different stages of dilution, the
 celebrated  Kirwan  has long  misled  the
 chemical world.  He  asserted,  that the
 mean specific gravity of the components,
 being also the experimental mean, there is
 no condensation of volume, as with  other
 acid  dilutions.   And the illustrious Ber-
thollet has  even assigned a cause  for this
                      56 
SPE
SP1
suppositious fact.   I find, on the contrary,
that 50 of acid, sp. grav. 1.1920 with 50 of
water, give out heat, and have their volume
diminished in the ratio of 100 to  99.28.
The experimental specific grav. is 1.0954;
that, by the exact rule, is only 1.0875.
  The preceding formula may be presented,
under a still more convenient form.   P, p
being  the  specific gravities of the two
                     «    W   .      w
components, we have P = y- and P=—'<

whence V = p, v = -•
  In the condition when W = w = 1,  we
have then

      V = jr» v  = —» and, consequently,
therefore
2A=(P-j»)X
P + p
~ + T
 P    P
^_(P-/0(A-P)
        P + P
  This value being  constantly negative,
proves that the true value of the sp. grav.

of the mixture, represented «y-   — —»

is  always  smaller than the  false value,
 1 / W    w \
~( V + -)'
  Example of the last formula,
     ,,    , .,     19.3-+-10.5
  Gold and silver, ----y----= 14.9 =

false or arithmetical mean specific gravity.
(P_^)2   (19.3—10-5)2 _ (8.8)3 _77.44
 P+p ~     29.8     ~~  29.8    29.8
=  2.6 = 2 A;  and A =  13» which be-
ing subtracted from the arithmetical mean
14.9, leaves 13.6 for the true mean specific
gravity as directly obtained by the formula
(W + w) Vp
  Pie -f- ^W
               SULPHURIC ACID TABLE,

Showing the erroneous results of the common method.  See Allov.
Acid in 100.	Arithm. mean density.	Experi-mental density.	Apparent volume.	a .,. i Arithm. Acidin\ inn mean density.		Experi-mental density. 1.3884 1.2999 1.2184 1.1410 1.0680	Apparent volume. 102.6 103.02 102.95 102.50 101.57
100 90 80 70 60	1.7632 1.6784 1.5936 | 1.5088	1.8480 1.8115 1.7120 1.5975 1.4860	100 97.3 98.0 99.7 101.5	50 40 30 20 10	1.4240 1.3392 1.2541 1.1696 1.0848		
  • Specular Iron Ore.   See Ores of
Iron.*
  Speculum.  Mr. Edwards affirms, that
different kinds of copper require different
doses of tin to produce the most perfect
whiteness.  If the dose of tin be too small,
which is the  fault most easily  remedied,
the composition will be yellowish; if it be
too great, the composition will be of a gray-
blue colour, and dull appearance. He casts
the speculum in sand, with the face down-
wards;  takes  it  out  while  red-hot,  and
places it in hot wood ashes to cool; without
which precaution  it would break in cooling.
   Mr. Little  recommends  the following
proportions;—32 parts of the best bar cop-
per, 4 parts of the  brass of pin-wire, 16$
of tin, and 1| of arsenic.  Silver he rejects,
as it has an extraordinary effect of soften-
ing the metal; and he found, that the com-
pound was not susceptible of the highest
polish, unless it was extremely brittle. He
first melts the brass, and adds to it about
an equal weight of tin. When this mixture
is cord, he puts it into the copper, previ-
ously fused with black flux, adds next the
remainder of the tin, and lastly the arsenic.
This mixture  he  granulates, by  pouring
into cold water, as Mr. Edwards did, and
fuses it a second time for casting.
  * Spermaceti.   See Fat.*
  * Sphene.   Prismatic titanium ore.*
  * Sphoerulite.  Colours  brown and
gray.  In  imbedded roundish balls and
grains. Glimmering.  Fracture even, splin-
tery.  Opaque.  Scratches quartz with diffi-
culty.  Brittle. Sp. gr. 2.4 to 2.5.  Nearly
infusible.  It occurs in pearlstone and pitch-
stone porphyries, in the vicinity of Glass-
hiitte near Schemnitz; and in the pitchstone
of Meissen.*
  * Sphragide. See Lemnian Earth.*
  *  Spinel.  A sub-species of octohedral
corundum. Colour red.  Occurs in grains,
more frequently crystallized; in  a perfect
octohedron, which is the fundamental fi-
gure; in a tetrahedron, perfect or modified;
a thick equiangular six-sided table; a very
oblique four-sided table; a rhomboidal do-
decahedron; a rectangular four-sided prism. 
SPI
SPI
Splendent and vitreous.  Cleavage-fourfold.
Fracture flat conchoidal.   Translucent to
transparent. Refracts single. Scratches to-
paz, but is scratched by sapphire.  Brittle.
Sp. gr. 3.5 to 3.8  Fusible with borax.  Its
constituents are, alumina  82.47, magnesia
8.78. chromic acid  6.18,  loss 2.57.— Vau-
quelin.  It  is found in the gneiss district of
Acker  in  Sudermannland, in a primitive
limestone; in the kingdom of Pegu, and in
Ceylon.  It is  used as a  precious stone.
When it weighs four carats (about sixteen
grains), it is considered of equal value with
a diamond of half the weight.—Jameson*
  •  Spinellane.  Colour plum-blue.  It
occurs crystallized in  rhomboids  of 117°
23',  and 62° 37': and in six-sided prisms,
acuminated with three planes. It scratches
glass.  It is found on the shores ofthe lake
of Laach, in  a rock composed of glassy
feldspar, quartz, hornblende, &c. It is said
to be a variety of Haiiyne.*
  • Spinthere.   Colour greenish-gray.
In small  oblique double  four-sided pyra-
mids.  It does not scratch glass. It occurs
in the department of Isere in France, in-
crusting calcareous  spar crystals.  It is
believed to be a variety of sphene.*
  Spirit  of Mindererus.  A solution
of acetate  of ammonia, made  by adding
concrete carbonate of ammonia to distilled
vinegar till saturation takes place.
  Spirit  of Nitre.  See Acid  (Ni-
tric).
  * Spirit, (Pyro-acetic).  Some dry
acetates exposed to heat in a retort yield a
quantity of a light volatile spirit, to which
the above name is given. When the acetate
is easily decomposed by the fire, it affords
much acid and little spirit; and on the con-
trary it yields much spirit and little  acid,
when  a strong heat is required for its de-
composition.  The acetates of nickel, cop-
per, &c. are in the first condition; those of
barytes, potash, soda, strontian,  lime, man-
ganese, and zinc, are in the second.   The
following  table of M.  Chenevix,  exhibits
the products of the distillation of various
acetates.
Table of Pyro-Acetic Spirit.
	Acetate of Silver.	Acetate of Nickel.	Acetate of Copper.	Acetate of Lead.	Peracetate of iron.	AcetateoJ Zinc.	Acetate of Manganese
Loss by the fire,	0.36	0.61	0.64	0.37	0.49		0.555
B r State of the .sj base (a). j. "S-----------—	metallic.	metallic.	metallic.	metallic.	bl. oxide.	wh. oxide.	br. oxide.
tt; \_Resid. Carbon.	0.05	0.14	0.055 '	0.04	0.02	0.05	0.035
■a $ CSp. gr a-g< Ratio of acid. S^CPyro. spir.	1.0656 107.309 0	1.0398 44.731 almost 0	1.0556 84.863 0.17	0.9407 3.045 0.555	1.011 27.236 0.24	0.8452 2.258 0.695	0.8264 1.285 0.94
g f rCarb. acid, (b) g "§ < Carb. hydro. a I CTotal gas.	8 12 20	35 60 95	10 34 44	20 8 28	18 34 52	16 28 44	20 32 52
  We see, that of all the acetates, that of
silver gives  the  most  concentrated  and
purest acetic acid, since  it contains no py-
ro-acetic spirit.
  This spirit is limpid and colourless. Its
taste is  at first acrid and  burning,  then
cooling, and in some measure urinous. Its
odour approaches that of peppermint min-
gled with hitter almonds.  Its sp. grav. is

  (a) Almost all the  metallic residuums
are pyrophoric, or susceptible of inflaming
by contact of air, after complete refrigera-
tion; which M.  Chenevix ascribes to the
finely divided charcoal mixed with the me-
tallic part.
  (b) The quantities marked here, are ex-
pressed in volumes
0.7864.   It burns  with a flame interiorly
blue, but white on the outside. It boils at
138.2 F. and does  not congeal at 5° Fahr.
With water it combines in  every propor-
tion,  as well  as with alcohol, and most of
the essential oils.  It dissolves but a little
of sulphur and phosphorus, but  camphor
in very large quantity.
  Caustic potash has very little action on
the pyro-acetic spirit. Sulphuric and nitric
acids decompose it; but muriatic acid forms
with  this body  a compound, which is npt
acid, and in which  we can demonstrate the
presence of the muriatic acid,  only by ig-
neous decomposition.  Hence we  perceive
that pyro-acetic  spirit is a  peculiar sub-
stance, which resembles the ethers, alco-
hol, and volatile oils. To obtain it cheaply,, 
STA
STA
we may employ the acetate of lead of com-
merce.  After having distilled this  salt in
an earthen retort,  and collected the liquid
products in a globe, communicating by a
tube with a flask surrounded with ice, we
saturate these products with a solution of
potash or soda, and then separate the spirit
by  means of a second distillation,  taking
care to use a regulated heat. As it usually
carries over with it a little water, it is pro-
per to rectify it from dry muriate of lime
Ann. de Chimie, torn. 69.*
  * Spirit of Sal Ammoniac   Water
of Ammonia.*
  Spirit (Volatile) of Sal Ammo-
niac  See Ammonia.
  * Spirit of Salt.  See  acid (Muri-
atic).*
  * Spirit of Wine.  Alcohol.*
  * Spodumene.  Prismatic triphane spar.
—Mohs.   Colour between greenish-white
and mountain-gray. Massive, disseminated
and in large granular  concretions.   Glis-
tening, pearly.   Cleavage threefold. Frac-
ture fine grained uneven. Translucent. As
hard  as feldspar.  Most easily  frangible.
Sp, gr. 3.0 to 3.1.   Before the blow-pipe, it
first separates into small gold-yellow co-
loured folia; and if the heat is continued,
they melt into a greenish-white coloured
glass. Its constituents are, silica 64.4, alu-
mina  24.4, lime 3,  potash 5, oxide of iron
2.2.— Vauquelin.  It was first discovered in
the Island  of  Uton in Sudermannland,
where it  is associated  with red feldspar
and quartz. It has  been lately found in the
vicinity of Dublin, by Dr. Taylor.   It con-
tains  the new alkali lithia, by some recent
analyses.*
  Sponge. A soft, light, very porous, and
compressible substance, readily  imbibing
water, and distending thereby.  It is found
adhering to rocks, particularly in the Me-
diterranean Sea, about  the  islands of the
Archipelago.  It was formerly supposed to
be  a vegetable production, but is  now
classed among the  zoophytes; and analyzed,
it yields the same principles with  animal
substances in general.
   Stalactites.  These are found sus-
pended from vaults, being  formed by the
oozing of water charged with  calcareous
particles, and gradually evaporating,  leav-
ing those particles behind.
   Starch.  This is a white, insipid, com-
bustible substance, insoluble in cold water,
but forming a jelly with boiling  water.  It
exists chit fly in  the white and brittle parts
of vegetables,  particularly in  tuberose
roots, and the  seeds  of the gramineous
plants.   It  may be extracted by pounding
these parts, and agitating them in cold wa-
 ter; when the parenchyma or fibrous parts,
 will first subside; and these being removed,
a fine white powder, diffused through the
water, will gradually subside, which is the
starch.  Or  the  pounded  or grated sub-
stance,  as  the roots of arum, potatoes,
acorns,  or  horse-chesnuts, for instance,
may be  put  into a  hair-sieve,  and the
starch washed through with cold  water,
leaving the grosser matters behind.-  Pari.
naceous seeds may be ground and treated
in a similar manner.   Oily seeds require to
have the oil expressed from them before
the farina is extracted.
  If starch be subjected to distillation, it
gives out water impregnated with empy-
reumatic acetous acid; a little red or brown
oil, a great deal  of carbonic acid, and car-
buretted hydrogen gas.  Its coal is bulky,
easily burned, and leaves a very small quan-
tity of potash  and  phosphate of lime.  If
when diffused in water, it be exposed to a
heat of 60° F. or upward, it will ferment,
and turn sour; but much more  so  if it be
not freed from the gluten, extract, and co-
louring  matter.  Thus, in  starch-makinp,
the farina ferments and becomes sour, but
the starch that docs not undergo fermenta-
tion is rendered  the more pure by this pro-
cess.  Some water already soured is mixed
with the  flour and water,  which regulates
the fermentation, and prevents the mixture
from becoming putrid; and in this state it
is left about ten days in summer and fifteen
in winter, before the scum is removed, and
the water poured off.  The starch is then
washed out from the  bran, and dried,  first
in the open air, and finally in an oven.
  With  boiling water starch forms a nearly
trans])..rent  mucilage, emitting a peculiar
smell, neither disagreeable  nor very pow-
erful.  This mucilage may  be  dried, and
will then  be semi-transparent,  and much
resembling gum, all the products of which
it affords. When dissolved it is much more
easily digested and nutritious than before
it has undergone this operation.
   Both  acids  and alkalies combined with
water dissolve it.  It separates the oxides
of several metals from their solutions, and
takes oxygen from  many of them.   It is
found naturally  combined  with all the im-
mediate principles of vegetables, and may
easily be united with most of them by art.
   * Staurolite. Grenatite, or prismatic
garnet.*
   * Staurotide.  Grenatite,  prismatic
garnet,  or staurolite.  Colour dark reddish-
brown.   Only crystallized  in forms which
may be reduced to a prism of 129° 30'. The
following are secondary forms: a very ob-
lique four-sided  prism,  truncated on the
acuter lateral edges, forming an unequian-
gular six-sided prism; the same acutely be-
vel; 'd on the extremities; and a twin crys-
tal, formed by two perfect six-sided prisms.
Splendent,  resino-vitreous.  Cleavage  in
the  smaller diagonal.  Fracture,  small
grained uneven.  Opaque or translucent.
Scratches quartz feebly.   Brittle.  Sp. gr. 
                 STE

3.3 to 3.8.  Infusible.  Its constituents are,
alumina 44, silica 33, lime 3.84, oxide of
iron  13, oxide ofmanganese l.loss 5.16.—
Vauquelin. The geognostic relations of this
mineral are nearly the same with those  of
precious garnet.   It occurs  in  clay-slate
near Ardonald, between Keith and Huntly,
in Aberdeenshire, and in a micaceous rock
at the Glenmalur lead-mines in the county
of Wicklow, Ireland.*
   * Steam. See Caloric, and Vapour.*
  'Stearin.  See Fat.*
  'Steatite, or Soapstone.  A sub-
species of rhomboidal mica.  Colour gray-
ish, or greenish white.  Massive, dissemi-
nated, imitative, and in the following sup-
posititious figures: an equiangular six-sided
prism; an acute double  six-sided pyramid;
and a rhomboid. The first two are on rock
crystal, the last on calcareous spar.   Dull.
Fracture coarse splintery.  T-ranslucent on
the  edges.   Streak  shining.  Writes but
feebly.  Soft.  Very sectile.   Rather diffi-
cultly  frangible.   Does not adhere to the
tongue.  Feels very greasy.  Sp. gr. 2.4 to
2.6.   Infusible.  Its constituents are, silica
44, magnesia 44, alumina 2, iron 7.3, man-
ganese 1.5,  chrome 2.   Trace of lime and
muriatic acid. It occurs frequently in small
contemporaneous  veins, that traverse ser-
pentine in  all directions; at Portsoy and
Shetland; in the limestone  of Icolmkill; in
the serpentine of Cornwall:  and in Angle-
sey.   It is used in the manufacture of por-
celain,  and for taking  greasy spots out of
silk and woollen stuffs.  It is also employed
in polishing gypsum, serpentine, and mar-
ble.  When pounded and slightly burned, it
forms  the  basis  of certain cosmetics.  It
writes readily on glass.  Humboldt assures
us, that the Otomacks, a savage race on the
banks  of the Orinoco, live  for nearly three
months ofthe year, principally on a kind of
potter's clay; and many other savages eat
great quantities of steatite, which contains
absolutely no nourishment.*
   *  Steel. A modification of iron, con-
cerning which our knowledge is not very
precise, notwithstanding the  researches of
many celebrated chemists. For the follow-
ing important facts, I  am indebted to the
proprietor  of the Monkland  manufactory,
where bar and cast steel of superior quality
are made.
  The chests or troughs, in which the iron
bars are stratified, are 9 feet long, and com-
posed  of an open-grained siliceous  free-
Stone, unalterable by the fire.  The Danne-
mora or Oregrounds iron is alone employ-
ed, for conversion into steel,  at Monkland.
The increase of weight is  from 4 to 12
ounces per hundred Weight.  Tiie average
is therefore 1 in 224 parts.  The first pro-
portion constitutes mild, and  the second
very hard  steel.   Should the process  be
pushed much farther, the steel would then
melt, and in the act of fusion would take *
dose of  charcoal sufficient  to  bring it to
the state of No. 1. cast iron.  The charcoal
used in  stratifying with the bar  iron,  i9
bruised  so  as  to  pass through a quarter-
inch riddle.   Whenever the  interior of the
i roughs arrives at 70° Wedgwood,  the car-
bon begins  to be absorbed hy the iron.
There is no further diminution ofthe weight
of  the charcoal than what  is due to this
combination.  What remains is  employed
at another charge.   Great differences are
found  between the different kinds of bar
iron, imported at the same time; which oc-
casion unexpected differences  in  the  re-
sulting steel. The  following  letter contains
important information from a gentleman
possessing great experience in  the manu-
facture of steel.

             " Monkland Steel- Works,
                 " 9th November, 1820.
  "Sir—Mr. William Murray has written
me, that you wished  I should communicate
to  you the reason  why bar iron should run
into the state of soft cast iron,  by  the ope-
ration being carried too far in the blister
steel furnace;  and how it does  not make
cast steel, as cast steel is said to be formed
by  the fusion  of  the blister steel in the
crucible with charcoal
  " The usual practice of making cast steel
is to fuse common steel in a  crucible, with-
out any charcoal being mixed. The degree
of hardness  required in the cast steel is re-
gulated  by  selecting blister steel of the
proper degree of hardness for  what  is
wanted.
  " This statement is made  with a view to
correct a common mistake, that to make
caststeel it is necessary, and that it is the
practice, to  mix with the steel to be melted
a quantity of charcoal.
   " Pursuing this mistake it  naturally leads
to others. Dr. Thomson says, when speak-
ing on this subject,  that cast steel is more
fusible than common steel, and for that rea-
son it cannot be welded to  iron.  It melts
before it can he heated bigh enough; and
that the quantity of  carbon is greater than
in  common  steel;  and that  this seems  to
constitute the difference between the two
substances.
  " The statement  of a simple fact will
show  that  this conclusion  is  erroneous.
Suppose apiece of blister steel, pretty hard,
yet fit to stand the operation of welding to
iron without any difficulty; let this steel be
made  into cast steel  in  the ordinary way.
It will not then stand the process of weld-
ing.  It  will not melt before reaching the
welding heat;  but when brought to that
heat, and submitted to  the blows of the
hammer, it will fall like a  piece of sand,
and the parts being once separated, they
refuse to become again united.   This diffi- 
                  STI

 culty of working the steel cannot arise from
 the steel containing more carbon, for  the
 fact is, it contains less, part of it being
 burnt  out  in the operation  of melting it.
 And if the same  steel was to be melted a
 second time, more ofthe carbon would be
 burnt  out, of course the steel would be
 softer; but at  the same  time the difficulty
 of working it would be increased; or, in
 other words, the red-short property it had
 acquired in the first melting would be dou-
 bly increased in the second, although a
 person  who has  not  had the experience
 would  very naturally conclude, that as  the
 metal kept retrograding to the state of mal-
 leable iron, in the same proportion it would
 acquire all the properties of the metal in
 that state.   When taking this view  of  the
 subject, it would appear that the difference
 between these two kinds of steel must arise
 from some other cause than that pointed
 out by Dr. Thomson.
   " When the iron has absorbed a quantity
 of carbon in the blister steel furnace, suffi-
 cient to constitute steel of a proper degree
 of hardness, and the heat after this is con-
 tinued to be kept up,  the  steel will keep
 absorbing more and  more  carbon.  The
 fusibility of it will continue to increase,
just in the same proportion,  till at last it
 becomes so fusible, that even  the limited
 heat of  a  blister steel furnace brings it
 down; and just at the time it is passing to
 the fluid state, it takes so great a quantity
 of charcoal, as changes  it from the state
 of steel to that of cast iron.   It appears to
 me, that the charcoal is combined in rich
 cast iron, in the mechanical  state, and not
 in the chemical, as in steel.
   " With this  you will receive a specimen
 from the blister  steel furnace.  The frac-
 ture of the bar will show you steel in the
 highest state of combination with carbon
 in which it can exist; and another part  of
 the same fracture presents  the transition
 from the state of steel to that of cast iron.
 Should you require it, I will  send  you a
 specimen of cast steel in the  ingot,  and
 from the same ingot, one in  the hammered
 state.   I am," &c.
                    "John Buttery."*

   * Steinheilite.  Blue quartz of Fin-
 land.*
   * Stibium.  Antimony.*
   •Stilbite, or Pyramidal Zeolite.
 See Zeolite.*
   * Stilpnosiderite.   Colour brown-
 ish-black. Massive, imitative, and in curv-
 ed concretions. Splendent, resinous. Frac-
 ture conchoidal.  Opaque.  Streak yellow-
 ish-brown. Hard in a low degree.  Brittle.
 Sp. gr.  3.77  With borax it gives a dark
 olive-green glass. Its constituents are, ox-
 ide of iron 80.5, silica 2.25, water 16, oxide
 of manganese a trace.— Ullmann.  It is said
                STK

to contain phosphoric acid. It occurs alonf
with brown iron in Saxony and Bavaria.  It
is allied to meadow iron-ore.*
   * Stones.   See Analysis,  Earths,
Geology,  Meteorolite, and Mine-
ralogy.*
   * Stinkstone, or  Swinestonk.   A
variety  of. compact lucullite, a sub-species
of lime-stone.*
   * Strahlstein.  Actinolite.*
   Strontia.  About 35 years  ago a mi-
neral was brought to Edinburgh by a deal-
er in  fossils, from a lead-mine at Strontian
in Argyllshire,  which was generally consi-
dered as a  carbonate of barytes.  It has
since been found near Bristol, in France,
in Sicily, and in Pennsylvania.  Dr. Craw-
ford  first observed  some differences be-
tween its solution in muriatic acid, and that
obtained from the carbonate of barytes of
Anglezark, and thence supposed it to be a
new earth.  Dr.  Hope  of Edinburgh had
entertained the same opinion, and confirm-
ed  it by  experiments  in 1791.  Kirwan,
Klaproth, Pelletier,  and  Sulzer  did  the
same.  The carbonic acid may be  expelled
by a  heat of 140° of Wedgwood, leaving
the strontia behind; or by dissolving in the
nitric acid, and driving this off by heat.
  Pure  strontia is of a grayish-white co-
lour; a pungent acrid taste; and when pow-
dered in a mortar, the dust that rises irri-
tates  the  lungs and  nostrils.  Its specific
gravity approaches that  of barytes.  It re-
quires rather more than 160 parts of water
at 60° to  dissolve it;  but of boiling water
much less.  On cooling, it crystallizes  in
thin, transparent, quadrangular plates, ge-
nerally parallelograms,  seldom exceeding
a quarter of an  inch in length,  and fre-
quently adhering  together. The edges are
most  frequently bevelled from each side.
Sometimes they  assume a  cubic  form.
These crystals contain  about 68 of  water;
are soluble in  51.4 times their weight  of
water at 60°, and in little more than twice
their  weight of boiling water. They give a
blood-red colour to the flame of burning
alcohol    The solution of strontia changes
vegetable blues to a green.  Strontia com-
bines with sulphur either in the wet or dry
way,  and its sulphuret is soluble in water.
   In its properties, strontia has a consider-
able affinity to  barytes.   It differs from  it
chiefly  in being infusible, much less solu-
ble, of  a different form, weaker in its affi-
nities, and not  poisonous.  Its saline com-
pounds  afford differences more marked.—
Edinburgh Trans.
   * The basis  of strontia, is strontium, a
metal first procured by Sir H.  Davy  in
1808, precisely in the same  manner as ba-
rium, to which it is very analogous, but
has less lustre.  It  appeared fixed, diffi-
cultly fusible, and not volatile. It became
converted into strontia  by exposure to air', 
STR                                 STR
and when thrown into water, decomposed
it with great violence, producing hydrogen
gas, and making the water  a solution of
strontia.  By igniting the mineral  stronti-
anite  (see Heavy Spar)  intensely with
charcoal powder, strontia is  cheaply pro-
cured.  Sir H. Davy, from indirect experi-
ments, is  disposed to regard  it as com-
posed of about 86 strontium -f- 14 oxygen,
in 100 parts; and supposing it to be com-
posed of a prime proportion of each con-
stituent, the equivalent prime of strontium
would be 6.143,  and of strontia 7.143. But
from the proportions ofthe constituents in
the carbonate; the prime of strontia appears
to be 6.4  or 6.5; and hence that of stron-
tium will be 5.5.
  The beautiful red fire which is now so
frequently used  at the theatres, is com-
posed of the following ingredients: 40 parts
dry nitrate of strontian,  13 parts of finely
powdered sulphur, 5 parts of  chlorate of
potash (hyperoxymuriate), and 4 parts of
sulphuret of antimony.  The chlorate of
potash and sulphuret of antimony should
be powdered separately in a mortar, and
then mixed together on paper; after which
they may be added to  the other ingredi-
ents, previously  powdered and  mixed.  No
other kind  of  mixture  than rubbing to-
gether on paper is required.  Sometimes a
little realgar is added to the  sulphuret of
antimony, and   frequently when the  fire
burns dim and  badly, a very small quan-
tity of very  finely  powdered charcoal or
lampblack will make it perfect.
  For the saline combinations  of strontia,
see the  Acids at the begining of the  Dic-
tionary, or Dr.  Hope's  excellent original
dissertation on this earth, in the Edin. Phil.
Trans, for 1790.*
  • Strontianite. See Heavy Spar.*
  * Strontites.  The  same as strontia.*
  • Strontium.  The metallic  base of
strontia.*
  * Strychnia.   This alkaline substance
was detected by Pelletier and Caventou in
the fruit of the strychnos mix vomica, and
strychnos  ignatia, about  the  end  of the
year 1818.  It was obtained from the bean
of the strychnos ignatia  by the following
process:  The bean was  rasped down as
small as possible.   It was then exposed to
the action of nitric ether in a  Papin's di-
gester.  The residue,  thus deprived of a
quantity of fatty matter, was digested in
alcohol  as long as that reagent was capa-
ble of dissolving any thing.   The alcoholic
solutions vJpe evaporated to dryness, and
the residue redissolved in water.  Caustic
potash  being dropped into the  solution, a
white crystalline  precipitate  fell, which
was strychnia.   It was purified by washing
it in cold water,  dissolving it  in  alcohol,
and crystallizing it.  Strychnia was obtain-
ed likewise from the bean of the strychnos
ignatia by boiling the infusion of the bean
with magnesia, in the same manner as Ro-
biquet had obtained morphia from the in-
fusion of opium.
  The properties of strychnia, when in a
state of purity, are as follows:
  It is crystallized in very small four-sided
prisms, terminated by four-sided low pyra-
mids. It has a white colour, its taste is in-
tolerably bitter, leaving a metallic impres-
sion in the mouth. It is destitute of smell.
It is not altered by exposure to the air. It
is neither fusible nor  volatile, except at
temperatures at which it undergoes decom-
position.  It is charred at the temperature
at which oil enters into  ebullition (about
580*). When strongly heated, it swells up,
blackens,  gives  out empyreumatic  oil, a
little water  and  acetic acid; carbonic acid
and carburetted hydrogen gases are dis-
engaged, and a bulky charcoal remains be-
hind.   When heated with peroxide of cop-
per, it gives out only carbonic acid gas and
water.  It is very little soluble in cold wa-
ter, 100,000 parts of that liquid dissolving
only 15 parts of strychnia; but it dissolves
in 2500 times its weight of boiling  water.
A cold solution of strychnia in water may
be diluted with 100 times its volume of that
liquid without losing its bitter taste.
  When strychnia is introduced into the
stomach, it acts  with prodigious energy. A
locked jaw is induced in a very short time,
and the animal is speedily destroyed. Half
a grain of strychnia blown into the throat of
a rabbit proved fatal in five minutes, and
brought on  locked jaw in two  minutes.
  Sulphate of strychnia is  a salt which crys-
tallizes in transparent cubes, soluble in less
than ten times its weight of cold water. Its
taste is intensely bitter, and the strychnia
is precipitated from it by all the soluble
salifiable bases.   It is not altered by expo-
sure to the air. In the temperature of 212°
it loses no  weight,  but  becomes opaque.
At  a higher  temperature ft  melts, and
speedily  congeals again, with a loss  of
three per cent  of its  weight.  At a still
higher temperature  it is decomposed and
charred.  Its constituents are,
     Sulphuric acid,    9.5     5.00
     Strychnia,        90.5    47.63

                     100.0

   Muriate of strychnia crystallizes in very
small needles, which are grouped together,
and before the microscope exhibit the form
of quadrangular prisms.  When exposed to
the air, it becomes opaque. It is more solu-
ble in water than the sulphate, has a similar
taste, and acts with the same violence upon
the animal economy as all the other salts of
strychnia.   When heated to the  tempera-
ture at which the base is decomposed, it
allows the muriatic acid to escape. 
SULS
sun
  Phosphate  of strychnia crystallizes  in
four-sided prisms. It can only be obtained
neutral by double decomposition.
  Nitrate of strychnia can be obtained only
by dissolving strychnia in nitric acid, dilut-
ed with a great deal of water.   The satu-
rated solution, when cautiously evaporated,
yields crystals of neutral nitrate in pearly
needles.  This salt is much more soluble
in hot than in cold water.  Its taste is ex-
ceedingly bitter, and it acts with more vio-
lence upon the animal  economy than  pure
strychnia. It seems capable of uniting with
an excess  of acid.  When heated, it be-
comes  yellow, and undergoes decomposi-
tion.  It is slightly soluble in alcohol, but
is insoluble in ether.
  When concentrated nitric acid is poured
upon strychnia, it immediately  strikes  an
amaranthine colour,  followed  by a shade
similar to that of blood.  To  this colour
succeeds a  tint of yellow, which passes
afterwards into green.   By this action the
strychnia seems to be altered in its pro-
perties, and to be converted into a sub-
stance still capable of uniting with  acids.
  Carbonate of strychnia is obtained in the
form of white flocks, little soluble in water,
but soluble in carbonic acid.
  Acetic, oxalic, and tartaric acids form
with strychnia neutral salts, which are very
soluble  in water, and more or less capable
of crystallizing. They crystallite best when
they contain an excess  of acid.  The neu-
tral acetate is very soluble, and crystallizes
with difficulty.
  Hydrocyanic acid dissolves strychnia, and
forms with it a crystallizable salt.
  Strychnia combines neither with sulphur
nor carbon.  When boiled with iodine, a
solution takes place, and iodate and hydri-
odate of strychnia are  formed.  Chlorine
acts upon it precisely in the same  way.
  Strychnia, when dissolved in alcohol, has
the property  of precipitating  the greater
number of m£allic oxides from their acid
solutions.  It is precipitated by the alkalis
and  alkaline earths; but the effect of the
earths proper has not been tried. See Ann.
de Chim. et de Phys. x. 142.*
  •Suber.  Cork. See Cerin, and Acid
(Suberic).*
  Sublimation is a process by which vo-
latile substances  are raised by  heat, and
again condensed  in the solid form.
  This operation is founded on the  same
principles as distillation, and its rules  are
the same, as it is nothing but a  dry distil-
lation.  Therefore all that has been said on
the  article  Distillation  is  applicable
here, especially in those cases where sub-
limation is  employed to separate  volatile
substances from others which are fixed or
less volatile.
  Sublimation is also used in  other cases:
for instance, to combine volatile matters
together, as in the operation of the subli-
mates of mercury; or to collect some vola-
tile substances, as sulphur, the acid of bo-
rax, and all the preparations called flowers.
   The apparatus for sublimation is  very
simple.  A matrass or small alembic is ge-
nerally sufficient for the sublimation of
small quantities of matter.   But the ves-
sels and the method of managing the fire,
vary according to the nature of the matters
which are  to be sublimed, and according to
the form which is to be given to the sub-
limate.
   The beauty of some sublimates consists
in their being composed of very fine, light
parts, such as almost all those called flow-
ers; as flowers of sulphur, of benzoin, and
others of this kind.   When the matters to
be sublimed are at the same time volatile,
a high cucurbit, to which is adapted a ca-
pital, and even several capitals placed one
upon another, are employed.   The subli-
mation is performed  in a sand-bath,  with
only the precise  degree of heat requisite
to raise the substance which is to be sub-
limed, and the capitals are to be guarded
as much as possible from heat. The height
of the cucurbit and of the capitals seems
well contrived to accomplish this intention.
   When along with the dry matter which
is to be collected in these sublimations, a
certain quantity of some liquor is  raised,
as happens in the sublimation of acid of
borax, and in the rectification  of volatile
concrete alkali, which is a  kind of subli-
mation, a passage and a receiver for these
liquors must be provided.   This is conve-
niently done by using the ordinary capital
of the alembic, furnished with a beak and
a receiver.
   Some sublimates are required  to  be in
masses as solid and compact as  their na-
tures allow.  Of this number are camphor,
muriate  of ammonia, and all the subli-
mates of mercury.  The properest vessels
for these sublimations are bottles  or ma-
trasses, which are to be sunk more or less
deeply in sand, according to the volatility
and gravity of the matters that are to be
sublimed.   In this  manner  of subliming,
the  substances having quitted the bottom
ofthe vessel, adhere to its upper part; and
as this part is low and near  the  fire, they
there suffer a degree of heat sufficient to
give them a kind of fusion.  The art, there-
fore, of conducting these sublimations con-
 sists in applying such a degree of heat, or
 in so disposing the sand (thafe is, making
 it cover more or less the matrfsf), that the
 heat in the upper part of the matrass shall
 be sufficient to make the sublimate adhere
 to the glass, and to give it such a degree
 of fusion as is necessary to render it com-
 pact; but at the same time this heat must
 not be so great as to force the  sublimate
through the neck of the matrass, and dis- 
SUG                                    SUG
sipate it. These conditions are not easily to
be attained, especially in great works.
  Many substances  may be  reduced into
flowers and  sublimed,  which require for
this purpose a very great heat, with the ac-
cess of free air and even the contact of coals,
and therefore  cannot be sublimed in close
vessels.  Such are most soots or flowers of
metals, and even  some saline substances.
When  tliese sublimates are required,  the
matters from which they are to be separated
must be  placed  among  burning coals in
open air; ami  the  flowers are collected in
the chimney of the furnace in which the ope-
ration is performed. The tutty, calamine, or
pompholix, collected in the  upper part of
furnaces in which ores are smelted, are sub-
limates of this kind.
  Suusalt. A salt having an excess of base
beyond what is requisite for saturating the
acid, as supersalt'xs one with an excess of the
acid. Thus sulphate of potash is the neutral
compound of sulphuric acid and potash; sub-
sulphate  of potash, a compound ofthe 6ame
ingredients, in which there is an excess of
base;  supersulphate of potash, a compound
of the  same acid and the same base, in which
there is an excess  of acid.  The term was
introduced by Dr  Pearson.
  * Succinates.   Compounds  of succinic
acid with the salifiable bases*
  * Succinic Acid.  See Acin (Succinic )*
  Suuar is a constituent part of vegetables,
existing in considerable quantities in a num-
ber of plants.  It is afforded by the maple,
the birch, wheat,  and Turkey corn.  Mar-
graaf obtained it from the roots of beet, red
beet,  skirret,  parsnips, and  dried  grapes.
The process of this chemist consisted in di-
gesting these r< >ots, rasped, or finely divided,
in alcohol.  This   fluid dissolves the sugar;
and leaves the extractive matter untouched,
which  falls to  Ae bottom.
  In Canada, the  inhabitants extract sugar
from the maple.   At the commencement of
spring, they heap  snow in  the evening at
the foot ofthe tree, in which they previous-
ly make apertures for the passage ofthe re-
turning sap.   Two hundred pounds of this
jdce, afford by evaporation fifteen ofa brown-
ish sugar.  The quantity prepared annually,
amounts to fifteen  thousand weight.
  Dr. Rush, in the Transactions of the Ame-
rican Philosophical Society, vol iii. has given
an account at length, of the  sugar maple
tree, of which the following is  a short ab-
stract;—
   The ucer saccharinum of  Linnxus, or su-
gar maple tree, grows in  great  quantities
in the western counties of all the middle
States of  the American Union.  It is as tall
as the oak, and from two to three feet in
diameter; puts forth a white blossom in the
spring, before any appearance of leaves; its
small branches afford sustenance  for cattle,
aud its ashes afford a large quantity of ex-
     VOL. II.
cellent potash.  Twenty years are required
for it to attain its full growth.   Tapping
does not injure it; but, on  the contrary, it
affords more sirup, and of a better quality,
the oftener it is tapped.  A single tree has
not only survived, but flourished, after tap-
ping, tor forty years. Five or six pounds of
sugar are usually afforded by the sap of one
tree; though there are instances of the quan-
tity exceeding twenty pounds. The sugar is
separated from the sap  either by freezing,
by spontaneous evaporation, or by boiling.
The latter method is the most used.  Dr.
Rush describes the process; which is sim-
ple, and practised without any difficulty by
the farmers.
  From frequent trials of this sugar, it does
not appear to be in any  respect  inferior to
that ofthe West Indies.  It is prepared at
a time  of the year when neither insect, nor
the pollen of plants exist to vitiate it, as is
the case with common sugar. From  calcu-
lations grounded on facts,  it is ascertained,
that America is now capable of producing a
surplus of one-eighth more  than  its own
consumption; that is, on the whole, about
135,000,000 pounds;  which, in the country,
may be valued at fifteen pounds weight for
one dollar.
  The Indians likewise extract  sugar from
the pith of the bamboo.
  The beet has lately been  much cultivated
in Germany,  for  the purpose of extracting
sugar from its root.  For this the roots are
taken  up in autumn, washed clean, wiped,
sliced  lengthwise, strung  on threads,  and
hung up to dry.   From these the sugar is
extracted by  maceration in  a small quantity
ot water; drawing off this upon fresh roots,
and adding fresh water to the first roots,
which  is  again to be employed the same
way, so as to get out all  their sugar, and sa-
turate  the water as much as possible with it.
This water is to be strained and boiled down
for the sugar.
  Some merely express  the juice from the
fresh roots, and boil this down; others  boil
the roots;  but the sugar extracted in either
of these ways is not equal in quality to the
first.
  Professor Lampadius  obtained from  110
lbs. ofthe roots, 4 lbs of well grained white
powder sugar; and the residuums afforded
7 pints of a spirit resembling rum.  Achard
says, that about a ton of roots  produced
him a 100 lbs. of raw sugar; which  gave
55 lbs. of refined sugar, and 25 lbs. of trea-
cle.
   But the sugar which is so  universally used,
is afforded by the  sugar cane (arundo  sac-
chuiiferu,) which  is  raised  in our colonies.
When this plant is ripe, it is cut down, and
crushed by passing it between iron cylinders
placed perpendicularly,  and moved by wa-
ter or  animal strength.   The juice which
flows out bv this strong pressure is receive^
                    sr 
SUG                                   SUG
in a shallow trough placed  beneath the cy-
linder. This juice is called in the French su-
gar colonies vesou; and the cane, after hav-
ing undergone this pressure, i>  called be-
gasse. The juice is more or less saccharine,
according to the nature ofthe soil on which
the cane has grown, and the weather that
has predominated  dining its  growth.  It is
aqueous when the  soil  or the weather has
been humid; and in contrary circumstances
it is thick and glutinous.
   The juice  of the cane is  conveyed into
Doilers, where it is hoiled with wood ashes
and lime.  It  is subjected to the  same ope-
ration  in  three several boilers, care  being
taken to  remove  the  scum as it rises.  In
this  state it  is  called sirup; and is  again
boiled with lime  and  alum  till it  is sufli-
cieivlv concentrated, when it is poured into
a vessel ca led the cooler. In this vessel it is
agitated with  wooden stirrers, which  break
the crust  as it forms on the surface.  It is
afterward poured  into casks,  to  accelerate
its cooling;  and while  it is still warm, it is
conveyed inio barrels standing upright over
a cistern, and pierced through their bottom
with several holes stopped with cane.  The
sirup which is not condensed  filters tlirough
these canes into the cistern beneath;  and
leaves  the su^ar in the state called coarse
sugar,  or  muscovado.  This sugir is yellow
and fat, and is purified in the islands in the
following manner.   The sirup is boiled, and
poured into conical earthen vessels, having
a small perforation at the apex, which is
kept closed.   Each cone, reversed on its
apex, is  supported in another earthen ves-
sel  The  sirup is stirred together, and then
left to  crystallize.   At the end of fifteen or
sixteen hours, he hole in the point of each
cone is opened, that the impure sirup may
run out.   The base of these sugar  loaves is
then taken out, and white pulverized sugar
substituted  in its stead; which being well
pressed down, the whole is covered with
clay,  mdstened with  water.  This  water
filters through the muss, carrying the sirup
with it which was mixed  with  the  sugar,
but which by this management  flows into
a pot  substituted  in the place of the first.
Tiiis second fluid  is called fine sirup.   Care
is t*ken to moisten and  keep the clay to a
proper degree of softness, as it becomes dry.
The sugar loaves  are  af'terward  taken out,
and dried in  a stove for eight or ten  days;
after which they are pulverised, packed, and
exp< ried to Europe, where they are still far-
ther purified.
   The operation  of the French sugar re-
finers  consists in  dissolving  the  cassonade,
or clayeil sugar, in lime-water.,   Bullocks'
b'oou is added, to promote  the  clarifying;
a.d, when  the liquor  begins to boil, the
heat is diminished, and  the scum carefully
tak«.n off.  It is in the  next place concen-
trated by a brisk heat; aud, as it boils up,
a small quantity  of butter is thrown in, tu
moderate  its agitation.  When the boiling
is sufficiently effected, the  fire is put out;
the liquor is poured into moulds, and agi-
tated, to mix the sirup together  with  the
grain sugar already formed.    When  the
whole is cold, the moulds are opened, and
the loaves are covered with moistened clay,
which is renewed from time to time till  the
sugar is well cleansed from  its  sirup.  The
loaves being then taken out of the moulds,
are carried to a  stove, where they are gra-
dually heated to 145°  F.   They remain in
this stove  eight  days, after  which they  are
wrapped in blue paper for sale.
  The several sirups,  treated  by the same
methods, afford  sugars of inferior qualities;
and the iast portion, which no longer affords
any crystals, is sold by the name of molasses.
The Spaniards use this molasses in the pre-
paration of sweetmeats.
  A solution of sugar,  much  less concen-
trated than that  we have just been speaking
of, lets fall by repose crystals,  which  affect
the form of tetrahedral prisms, terminated
by  dihedral  summits, and  known by  the
name of sugarcandy.
  The preceding account of the  manufac-
ture of sugar in the colonies is chiefly ex-
tracted from  Chaptal.    The  following is
taken from Edwards' History  of the West
Indies, the  authority of which is indubita-
ble.
  Such planters as are not fortunately fur-
nished with the means of grinding theircanes
by water,  are at  this season frequently im-
peded by the failure or insufficiency of their
mills; for though a sugar mill is a very sim
pie contrivance, yet great force is requisite
to make it vanquish the resistance which it
necessarily meets with.   It principally con-
sists of three upright iron rollers or cylind-
ers, from thirty to forty inch^ in length, and
from twenty to  twenty-five  inches in  dia-
meter;  and the middle  one,  to which the
moving power is applied, turns the other two
by me^ns of cogs.  The canes, which are
previously cut short and tied into bundles, are
twice compressed between these rollers; for
after they  have  passed through the first and
second rollers,  they are  turned round  the
middle one by  a piece of frame work of a
circular form, which is called in Jamaica the
dumb-returner, and forced back through the
second and third   By this operation they
are squeezed completely dry, and  some-
times even reduced to powder.  The cane-
juice is received in a leaden bed, and thence
conveyed into a vessel called  the receiver
 The refuse,  or macerated rind of the cane,
 which is called cane-trash, serves for fuel to
 boil the liquor.
   The  juice from the mill  usually contains
 eight parts of pure water, one part of sugar,
 and one part made up of gross oil and mu-
 cilage, with a portion of essential oil.  The 
SUG                                   SUG
proportions  are  taken at a  medium;  for
some juice has been so rich as to make a
hogshead or sixteen hundred weight of sugar
from thirteen hundred gallons, and some is
so watery as to require more than double that
quantity.  The richer the juice is, the less
it abounds with redundant oil and gum; so
that very little knowledge of the contents
of any other quantity  can be obtained by
the most exact analysis of any one quantity
of juice.
  The following matters are likewise usually
contained in cane-juice. Some ofthe green
tops, which serve to tie the canes in bundles,
are often ground in, and yield a raw acid
juice  exceedingly disposed to ferment and
render the whole liquor sour.  Beside these
they grind in some pieces of the ligneous
part of the cane,  some dirt, and lastly, a
substance of some  importance, which may
be  called the crust.   This substance is a thin
black coat of matter that surrounds the cane
between the joints, beginning at each joint,
and gradually growing thinner the farther
from the joint upwards, till  the upper part
between  the joints appears entirely  free
from  it, and resumes  its bright \ ellow co-
lour.  It is a fine black powder, that mixes
with the clammy exudations from the cane;
and as the fairness of the sugar is one symp-
tom of its  goodness,  a small quantity of
this crust must very  much  prejudice  the
commodity.
   The sugar is  obtained by the  following
process:—The juice or liquor runs from the
receiver to  the boiling-house, along a wood-
en gutter fined with lead.  In the boiling-
house,  it is received into one ofthe copper
pans or caldrons, called clarifiers.   Of these
there are generally three; and their  dimen.
sions are  determined by the power of sup-
plying  them with liquor.  There are  wa-
ter mills that will  grind  with  great  facility
sufficient for thirty hogsheads of sugar in a
week.   Methods of quick boiling cannot be
dispensed with on plantations thus fortunate-
ly  provided; for otherwise the cane liquor
would unavoidably become tainted before it
could be exposed to the fire.  The purest
cane-juice will  not remain twenty minutes
in the receiver without fermenting.  Hence,
clarifiers are sometimes seen  of  one thou-
sand gallons each.  But on plantations that,
during crop time, make from fifteen to twen-
ty hogsheads of sugar a-week, three clari-
fiers of three or four hundred gallons each
are sufficient.  The liquor, when clarified,
 may be drawn off at once, with pans of this
 size, and there  is  leisure  to cleanse the
 vessels every time they are used. Each cla-
 rifier is furnished either with  a  siphon or
 cock for drawing off the liquor.   It has a
 flat bottom, and is hung to a sepaiate fire,
 each chimney having an iron slider, which,
when shut, causes the fire to be extinguished
through want of air §
  As soon as the stream from the receiver
has filled the clarifier with fresh liquor, and
the fire is lighted, the temper, which is ge-
nerally Bristol white-lime in powder, is stir-
red into it.  This is done, in order to neu-
tralize the superabundant  acid,  and to get
rid of which is the greatest difficulty in su-
gar making.  Alkali, or lime, generally ef-
fects this; and at the same time, part of it is
said to become the basis of the sugar.  Mr.
Edwards affirms, that it  affects both the
smell and taste of the  sugar.  It falls to the
bottom of the pans in a black insoluble mat-
ter, which scorches the bottom  of  the ves-
sels, and cannot without difficulty be  de-
tached from them.   But, in order  that less
of the lime  may be precipitated to the bot-
tom, little more than half a pint of Bristol
lime  should be allowed to every  hundred
gallons  of liquor, and Mr. Bousie's method
of dissolving it  in boiling water previous to
mixing  it  with the cane-juice should be
adopted t
   As the force ofthe fire increases, and the
liquor grows hot, a scum is thrown up, which
is formed of the gummy matter of the cane,
with some ofthe oil, and such impurities as

   § The  clarifiers are generally placed in
the middle or at  one end of the boiling-
house.   M'hen  they are placed at  one end,
the boiler called the teache is placed at the
other, and three boilers are usually ranged
between them. The teache commonly holds
from 70 to 100 gallons, and the boilers be-
tween the clarifiers and teache diminish in
size from the first to the last.  But when the
clarifiers are in the middle, there  is gene-
 nerally  a set of three boilers on each side,
which in effect forma double boiling-house.
 This arrangement is veiy necessary on large
estates.
   t Mr. Bousie, to whom, for his improve-
ments in the art of sugar-boiling, the Assem-
bly of Jamaica  gave 1000/, in a paper which
he distributed among the members, recom-
 mends the use  of vegetable alkali, or ashes
 of wood, such as pimento tree, dumb cane,
fern tree, cashew, or logwood,  as affording
 a better temper than quicklime. Afterward,
 however, he was convinced, that sugar form-
 ed on the basis of fixed alkaline salts never
 stands the sea,  unless some earth  is  united
 to the salts  Such earth as approaches near-
 est to the basis of alum, Mr. Edwards thinks,
 would be most proper; and it deserves to be
 inquired, how far a proper mixture of vege-
 table alkaline salts and lime might prove a
 better  temper than either lime or alkaline
 salts alone. In some parts of Jamaica, where
 the cane-liquor was exceedingly rich, Mr.
 Bousie made very good sugar without a par
 tide of temper. 
SUG
SUG
the mucilage is able to entangle.  The heat
is now suffered to increase gradually till it
nearly rises to the heat  of  boiling water.
The liquor, however, must by no means be
suffered to boil.   When the scum begins to
rise  into blisters,  which break into white
froth, and  gene-ally appear  in about forty
minutes, it is known to be sufficiently heat-
ed.  Then the damper is applied, and the
fire extinguished; and, if  circumstances will
admit, the liquor after this is suffered to re-
main a full hour undisturbed.   In the next
place, it is carefully drawn off, either by a si-
phon, which draws up the clear fluid through
the scum, or by means of a cock at the bot-
tom. In either case,  the scum sinks down
without breaking  as the liquor  flows; for
its tenacity prevents any admixture.   The
liquor is received into a gutter or channel,
which conveys it to the evaporating boiler,
commonly called the grand copper; and if
produced at first from good and untainted
canes, it will  then appear almost transpa-
rent.
  In the grand or evaporating copper, which
should  be sufficiently large  to receive the
net contents of one of the clarifiers, the li-
quor is suffered to boil, and  the scum,  is it
rises, is continually taken off by large scum-
mers, till the liquor becomes finer and some-
what thicker.   This operation is continued,
till the subject is so reduced  in quantity,
that it may  be contained in the next or se-
cond copper,  into which it  is then ladled.
The liquor is now almost of the colour of
Madeira wine.  In the second copper the
boiling and scumming are continued; and if
the subject be not so clean as  is expected,
lime-water is  thrown into it.   This addition
not  only serves to give more temper,  but
likewise to  dilute the  liquor, which some-
times thickens too fast to permit  the fecu-
lencies to rise in the scum. W hen the froth
in boiling arises in large  bubbles, and is not
much discoloured, the  liquor is said to hav«
a favourable appearance  in the second  cop-
per. When,  in consequence of such scum-
ming and evaporation, the liquor is again so
reduced, that it may be contained in the
third copper, it is ladled into it, and so on to
the  last copper, which is called the^teache.
This arrangement supposes four boilers or
coppers, besides the three clarifiers.
   In the teache the subject  undergoes an-
other evaporation, till it is supposed boiled
enough to be removed from the  fire.   This
operation is usually called striking, t. e.  lad-
Dngthe liquor, which is now exceeding thick,
into the cooler.
   The cooler, of which there are generally
six, is a shallow wooden vessel, about eleven
inches deep, seven feet in length, and  from
five to six feet wide.   A  cooler of this size
holds a hogshead of sugar.  Here the sugar
grains, *'. e. as it cools, it runs into a coarse
irregular mass of imperfec*  crvstal*,  «ep!t<
rating itself from the molasses  From the.
cooler it is taken to the curing-house, where
the molasses drains from it.§
  But here it may he proper to notice tli*—
rule for knowing when the  subject is fit to
be ladled from the teache to the cooler. Ma-
ny of the negro boilers, from long habit,
guess accurately by the eye alone, judging
by the appearance of the grain on  the bark
of  the  ladle; but the  practice  generally
adopted is to judge  by what is called the
touch, i. e. taking up with the thumb a small
portion of the hot liquor from the ladle, and,
as the heat diminishes, drawing with the fore-
finger the liquid into a thread.  This thread
will suddenly break and shrink from the
thumb to the  suspended finger, in different
lengths, according as the liquor is more or
less boiled.   A  thread of a  quarter' of an
inch  long generally determines  the pro-
per boiling height for strong  musco\ado
sugai'4
  The curing-house is a large airy building,
provided with a capacious molasses cistern,
the sides of which are sloped and lined with
terras, or boards.  A frame of massy joist-
work without boarding, is  placed over tliis
cistern; and empty hogsheads without head-
ings are ranged on the joints of this  frame.
Eight or ten holes are bored in the bottoms
of  these hogsheads, and through each of
the holes the stalk of a  plantain  leaf is

  § It is necessary to observe in this place,
that,  in order to obtain a large-grained su-
gar, it must  be suffered to cool slowly and
gradually.  If the coolers be too shallow,
the grain is injured in a  surprising man-
ner.
  \ The  vessel called the teache  probably
derived its name from this practice of trying
by the touch  (tactio.) Some years ago, John
Proculus Baker, Esq. barrister at law, re-
commended  to  the  public a method more
scientific and certain, in a treatise which he
published in  1775, entitled, An Essay on the
Art of  making Muscovado Sugar.  It is  as
follows:«' Provide a 9mall thin pane of clear
crown glass, set in a frame, which I would
call a tryer; on this drop two or three drops
ofthe subject, one on the other, and carry
your tryer out ofthe boiling-house into the
air.  Observe your subject, and more parti-
cularly whether it grain freely, and whether
a small edge of molasses separate at the bot-
tom.  I am well satisfied, that a little expe-
rience will enable you to judge what appear-
ance  the whole  skip will put on when cold,
by this specimen, which is also cold.  This
method  is used by  chemists, to try evapo-
rated solutions of all  other salts:  it may
seem therefore somewhat  strange,  it  has
not  been long  adopted in the  boiling-
house." 
SUG                                   FUG
Vbffi«t  six or eight inches below the joists,
and long enough to  stand  upright above
the top of the hogshead.  Irto these hogs-
heads, the mass from the cooler is put, which
is  called potting; and the molasses drains
through the spongy  stalk, and drops  into
the cistern, whence it is occasionally taken
for distillation. In the space of three weeks,
the sugar becomes tolerably  dry and fair. It
is then said to be cured, and the process is
finished.
  Sugar  thus obtained is called muscovado,
and is the raw material whence the  British
sugar-bakers chiefly  make their loaf or re-
fined lump. There is another sort, which was
formerly much used in Great Britain for do-
mestic  purposes, and was generally known
by the name  of Lisbon sugar.   In the West
Indies, itis called clayed sugar; and the pro-
cess of making it is as follows;—
   A quantity of sugar from the cooler is
put into  conical pots or pans, which  the
French call formes,  with  the points down-
ward, having a  hole about half an  inch in
diameter at the  bottom, for  the molasses to
drain through,  but which at first is closed
with a plug.  As soon as the sugar in these
pots is cool, and  becomes  a  fixed body,
which is known by the middle of the  top
falling in, the plug is taken out, and the pot
placed over a large jar, intended to receive
the sirup or  molasses that drain from it.  In
this state it is  left as long as  the molasses
continues to drop, when a stratum  of clay
is spread on  the sugar, and  moistened  with
water.   This, imperceptibly oozing through
the pores of the clay, dilutes the molasses,
in consequence of which  more of it comes
away than from sugar cured in the hogs-
head, and the  sugar of course becomes so
much whiter and purer. Accordingto Sloane,
the process was first discovered in Brasil, by
accident: " A hen,"  says he,  " having her
feet dirty, going over a pot of  sugar, it was
found  under her feet to be whiter than else-
where." The reason assigned why this pro-
cess is not universally adopted in the  Brit-
ish sugar islands is this, that the water which
dilutes and carries away the molasses, dis-
solves and carries with it so much of the su-
gar, that the difference in quality does not
pay for the difference in quantity.  It is pro-
bable, however, that the French planters are
of a different opinion:  for upwards of four
hundred of the  plantations of St. Domingo
have the necessary  apparatus  for  claying,
and actually carry on the system.
   Sugar is very soluble in  water,  and is a
good medium for uniting that fluid with oily
matters.   It is much used for domestic pur-
poses, and appears on the whole to be  a va-
luable and wholesome article  of food, the
uses of which are most probably restricted
by its high price.  This price may in a cer-
tain degree arise from the nature of the ar-
ticle, and its original cost; but is no doubt
in a great  measure owinr? to the inhuman
ard wasteful culture by slaves, and the ab-
surd principles of European  colonization,
duties,  drawbacks, and  bounties,   which.
have the effect to create unnatural  mono-
polies, and to prevent commerce from find-
ing its  level.  This  is eminently the case
with regard to our West-India islands, and
their produce.
  It appeai-s that sugar has the property
of  rendering  some  of the earths  soluble
in water.  This property was accidentally
discovered by Mr. William Ramsay of Glas-
gow.
   Being empWed in  making experiments
on sugar, and happening to put some  quick-
lime into a cold  solution of it, he noticed,
that it  had acquired an  uncommon caustic
taste.
   Hence he concluded, that sugar possesses
the property of dissolving a certain propor-
tion of lime; and in order to ascertain its ca-
pacity in this respect, experiments were made
upon this earth, together with strontites, mag-
nesia, and barytes.
   Sugar, dissolved in water at the tempera-
ture of 50°, is capable of dissolving one-half
of its weight of lime.
   The solution of lime in sugar is of a beau-
tiful white-wine  colour, and has the smell of
fresh slaked quicklime
   It is precipitated from the solution, by the
carbonic, citric, tartaric,  sulphuric, and oxa-
lic acids; and it  is decomposed, by double
affinity, by caustic and  carbonated  potash
and soda, the citrate, tartrate, and oxalate of
potash, &c.
   An equal weight of strontia, with the su-
gar employed, is capable of being dissolved
at the temperature of 212°, and of being re-
tained in solution by  the sugar  at  50°  of
Fahrenheit.  On exposing the crystals which
had fallen down during the cooling of the li-
quid, to the air of the atmosphere, they at-
tracted carbonic acid, and effloresced.
   The  solution of strontia in sugar is of a
fine white-wine  colour, and, like that  of
lime, has a  peculiar caustic  smell.    This
earth is precipitated by cnustic and carbo-
nated potash and soda; also by the carbonic,
citric, tartaric,  sulphuric, and oxalic  acids;
and it is decomposed, by compound affinity,
by tlie  carbonates of  potash  and  soda; also
by the citrate, tartrate, and oxalate of pot-
ash.
   The  solution of magnesia  in snip, like
those of lime and strontia, was of a pure
white colour, and had no sensible variation
in smell or taste from the common solution
of sugar, farther than that the sweet seemed
much improved,  and  was softer  and more
agreeable to the palate, as if it were entirely
freed from the earthy taste, which unrefined
sugar frequently has   On its remaining at
rest for some months, in a bottle well corked,
the magnesia appears to be entirely separated. 
SUG                                   SUG
  Very little alumina is dissolved by a solu-
lion of sugar, when  fresh precipitated earth
is presented to it, either in the cold or hot
state.
  The union ofthe  sugar with the alkalis,
has been long known; but this is rendered
more  strikingly evident, by carbonated pot-
ash or soda, for instance, decomposing the
solutions of lime and  strontia in sugar, by
double affinity.
  In  making  solutions of unrefined sugar
for culinary "purposes,  a gray-coloured sub-
stance is found frequently precipitated.   It
is probable, that this proceeds from a  super-
abundance of lime,  which has been used in
clarifying the juice of the sugar-cane at the
plantations abroad.  Sugar with this imper-
fection is known among the refiners  of this
article by the name of weak.  And it is justly
termed so, the precipitated matter being no-
thing  but lime which has attracted carbonic
acid from the  sugar, (of which  there  is a
great  probability,) or from the air ofthe at-
mosphere. A bottle in which I had kept a
solution  of lime in  sugar for at least four
years, closely corked, was entirely incrusted
with a yellowish-coloured matter, which on
examination was found to be entirely carbo-
nate of lime.
  * In the ordinary refining of raw  sugars,
from twenty to thirty-five per cent of molasses
are separated, of which a considerable part,
probably two-thirds, are formed by the high
heat used in the concentration of the sirup.
Various plans  have been contrived to dimi-
nish this production of molasses.  One  of
these consisted in surrounding  the  sugar-
boiler with oil or steam at a  high tempera-
ture,  instead of exposing it to a naked fire.
In a second, the boiler is covered at top, and
by means of an air-pump the atmospheric
pressure  is removed, so as to favour ebul-
lition, and rapid  evaporation, at moderate
heats.
  The celebrated chemist, Mr. Howard, took
out a patent for this plan, which  is undoubt-
edly the  most scientific  and productive of
anv; but requires  superior skill and very
minute attention in  the manufacturer.   No
blood is  used  for clarification.  This is ac-
complished by a system  of  most ingenious
canvas filters,  aided  by  the intermixture
with the  sirup, of a small quantity of pasty
gypsum and alumina, made by saturating a
solution  of alum with  quicklime.   In  the
Unal  purification, the  base of the inverted
sugar cone, is covered with a stratum of
very  pure saturated sirup, instead of moist
pipe-clay.
   The third method is founded on the pro-
perty which  animal charcoal (bone-black)
possesses, of destroying vegetable colouring
matter.  Perhaps the combination of the last
two modes promises the best results.
   A fourth process for refining sugar is that
 •f Mr. Daniel Wilson, for which a patent was
granted.   The specification is  in the 34th
vol. ofthe Uepertarv, p. 134.
  The pan is to be charged with strong lime-
water, the sugar .1.1(led, and the fire set in
the usual manner. For every hundred weight
of sugar used, a sdution is to  be  made of
four ounces  of sulphate of zinc,  in as small a
quantity of water as will dissolve it.  When
the sugar  in  the pan  is melted, the solution
of sulphate of zinc is added, and the whole
well stirred.   The oxide of zinc combines
with the extractive matter,  tannin and gallic
acid, and  renders them insoluble, while the
sulphuric acid, in combination with the lime,
becomes also insoluble.  When raw sugar
contains much acid,  and  a strong grain is
required,  take one ounce of lime in powder
for every  four ounces of sulphate of zinc,
and as much water as will form a  milk of
lime, which  is added to the solution of su-
gar in the pan, about five minutes after the
solution of sulphate of zinc has been added.
This purification of sugar by separating  im-
purities chemically combined with it, is em-
ployed with much advantage in conjunction
with the patent filtering apparatus invented
by Mr. John Sutherland.   The  solution of
sugar brought to  the boiling  point is run
through the filter, and afterwards boiled to
a proof.   Mr. Wilson boils the sirup in a
pan, having a coil  of tinned copper or pure
tin tubes  placed along its bottom and sides,
through which a constant stream of strongly
heated oil, or other fatty matter, is made to
pass.   The  oxide of zinc, precipitated pre-
viously by adding  a  solution of the salt to
lime-water,  is also recommended, as well as
the oxide of tin.
  Mr. Kirchoff, an ingenious Russian chemist
accidentally discovered, ihat starch  is con-
vertible  into  sugar, by being boiled  for
some time with a very dilute sulphuric acid.
Saussure  showtd,  that 100 parts ot starch
yield 110  of sugar.   He concluded, that  this
sugar is  merely a compound  of water  and
starch.  According to his analysis, starch con-
sists of

          Oxygen,     55.87
          Carbon,     37.29
          Hydrogen,    6.84

                      100.00

   Sugar  of grapes,  according  to the same
 chemist,  is  composed of

          Oxygen,     56.51
          Carbon,     36.71
          Hydrogen,    6.78

                      100.00

   Common sugar has been analyzed by ma-
 ny eminent chemists.  The following is a
 general view of the results: 
SUG                                   SUG
Berzelius.	Prout.
Mean of 3.	
49 856	53.33
43.265	39.99
6.879	6.66
 Gay-Lussac and
   Thenard.
Oxvgen,  50.63
Carbon,   42.47
Hydrogen, 6.90
          100.00    100.000       100.00
  For a view of the proportions of the con-
stituents referred to equivalent primes or
volumes, see Fekmf. station, column 4.   I
am happy to observe,  that Dr. Prout's ex-
perimental results agree with M. Gay-Lus-
sac's theory, of sugar being a compound of
40 parts of carbon -f- 60 of water, or its ele-
ments.  By Berzelius'  analysis, starch con-
sists of        Oxvgen,   49.5
               Carbon,   43.5
               Hydrogen, 7.0

                         100.0
  The abstraction of a little  hydrogen and
carbon, would  convert it into sugar.  But
no carbonic acid or other gas is e vtricated
during the conversion, according to Vogel's
experiments.   I find that potatoes digested
with dilute sulphuric acid, yields sugar cheap-
ly and abundantly. The acid is afterwards re-
moved by chalk; and the strained liquor left
to repose, after due evaporation, affords crys-
tals of sugar. From starch sugar, good beer
has been made.  I would recommend pota-
toes for this  purpose.  They are washed,
grated down, and treated with the dilute acid
for a day or two at a temperature of 212°.
  M. Braconnot has recently extended  our
views concerning the artificial production of
sugar  and  gum.  Sulphuric  acid  (sp. gr.
1.827) mixed with  well dried elm dust, be-
eame very hot, and  on  being diluted with
water, and neutralized with chalk, afforded
a liquor, which became gummy on evapora-
tion.  Shreds  of linen triturated in a glass
mortar, with sulphuric aoid, yield a similar
gum.   Nitric acid has a  similar power.   If
the gummy matter from hnen  be boiled for
some time with dilute  sulphuric acid, we ob-
tain a crystallizable sugar, and an acid, which
M. Braconnot calls the vegeto-sulphuricacid.
The conversion of wood also into sugar, will
no doubt appear remarkable; and when per-
sons not familiarized with chemical specula-
tions are told,  that a pound weight  of rags
can be  converted into  more than a pound
weight of sugar, they  may regard the state-
ment as a piece of pleasantly,  though no-
thing, says M. Braconnot, can be more real-
  Silk is also convertible into gum by sul-
phuric acid.  Twelve grammes  of glue, re-
duced to powder, were digested with a double
weight of concentrated sulphuric acid with-
out artificial heat. In twenty hours the liquid
was not more coloured than if  mere water
had been employed. A decilitre of water was
then added, and the whole was boiled for 5
hours, with renewal ofthe water, from time
to time, as it  wasted.  It was next diluted,
saturated with chalk, filtered and evaporated
to a sirupy consistence, and left in repose
for a month.  In this period a number  of
granular crystals had separated, which ad-
hered pretty  strongly to the bottom of the
vessel, and had a very decided saccharine
taste.   This sugar crystallizes  much  more
easily  than cane sugar.  The  crystals are
gritty  under the teeth,  like  sugar-candy;
and in the  form of flattened prisms or tabu-
lar groups.   Its taste is nearly as saccha-
rine as grape sugar; its solubility in water,
scarcely e xceeds that of sugar of milk.  Boil-
ing alcohol, even when diluted,  has no ac-
tion on this sugar.  By  distillation it yields
ammonia, indicating the  presence of azote.
This sugar combines intimately with  nitric
acid, without sensibly decomposing it, even
with the assistance of heat, and there results
a peculiar crystallized acid, to which the
 name nitro-saccharine has been given. An-
nates de Cldmie, xii. or  Tilloch's Magazine,
vol 55, and 56.
   The varieties of sugar are;  cane sugar,
maple sugar, liquid sugar of fruits, sugar of
figs, sugar of grapes, starch sugar, the mush-
 room sugar of Braconnot,  manna, sugar of
 gelatin, sugarof honey, and sugar of diabetes.
 " The relation," says Dr. Prout, "which ex-
 ists between urea and sugar, seems to explain
 in a satisfactory manner  the phenomena ol
 diabetes, which may be  considered as a de-
 praved secretion of sugar.   The weight of
 the atom of sugar, is just  half that of the
 weight of the atom of  urea;  the absolute
 quantity of hydrogen in  a  given weight of
 both is equal; while the absolute quantities
 of carbon and oxygen in a  given weight of
 sugar, are precisely twice those of urea."
   The constituents of these two bodies and
 lithic acid, are thus expressed by that inge-
 nious philosopher.
Elements.	Urea.			Sugar.			Lituic Acid.		
	No.	Per Atom.	Per Cent.	„- I Per Na | Atom.		Per Cent.	No.	Pei-Atom.	Per Cent.
Hydrogen, Carbon, Oxygen, Azote,	2 1 1 1	2.5 7.5 10.0 17.5	6.66 19.99 26.66 46.66 100.00	1 1 1 3	125 7.50 10.00	6.66 39.99 53.33	1 2 1 1	1.25 15.00 10.00 17.50	2.85 34.28 22.85 40.00
1	5	37.5			18.75	100.00	5	43.75	100.00
 
SUL                                   SUL
  "flhe  foregoing compounds appear to be
formed by the union of more simple com-
pounds; as sugar,  of carbon and  water;
urea, of carburetted hydrogen and nitrous
«>\ide; lithic acid, of cyanogen and  water,
tc. whence it  is interred, that their artifi-
cial formation falls within the limits of che-
mical operations.*
  * Scuau oi- Lead.  Acetate of lead.  See
Leah.*
   * Sulphates.   Definite  compounds of
sulphuric acid  with  the  salifiable  bases.
See Acm (StLrauaic,) and the respective
bases.*
  * Sulphites.   Definite compounds of sul-
phurous acid with the bases.*
  * Sulfihr.  Of native  or prismatic sul-
phur,  there  are two species, the common
and volcanic; the former is of two kinds com-
pact and earthy sulphur.
  §  1.  Compact  common  sulphur.   Colour
sulphur-} ellow, and yellow of other shades.
Massive, disseminated,  and cr}stallized.  Its
primitive figure  is  a  pvramid of 107° 19',
and 84° 24'; basis — 102° 41'.  The secon-
dary  figures are, the primitive variously
truncated, or acuminated, and delicate aci-
cular ciystuls. Shining or glimmering.  Clea-
vage prismatic and  axifrangible.  Fracture
uneven.   Translucent.   Refracts double.
Harder than talc. Brittle.   When rubbed,
it exhales a faint sulphureous smell, and be-
comes resino-electric.   Sp. gr. 1.9 to 2.1.
It occurs in considerable abundance in pri-
mitive mountains,  in a state of combination
with metals, forming the different genera of
pyrites, glance  and blende.  In  secondary
mountains it is more abundant in the pure
liiicombuied state.  It is found in the island
of Iceland, associated with gypsum;  or in
trusts  investing alluvial substances.   Aery
superb specimens of crystallized suiphur are
found at Conil near Cape Trafalgar.  It oc-
curs abundantly in Sicily,  at Urbino in the
Papal States, in Arragou in Spain, and Lau-
tiistein in Hanover.
   §  2.  Earthy common  sulphur.   Colour
pale  straw-}ellow.   Massive and dissemi-
nated. Dull.  Fracture  fine earthy. Opaque.
Does  not soil.   Soft to friable. It occurs in
cirusy cavities  in flint, and along with the
compact varieties,  in  gypsum  and  other
rocks.
  2. Volcanic sulphur.   Colour pale sulphur-
yellow.  Massive, imitative, and crystallized
in pyramids.  Glistening,  inclining to ada-
mantine.  I racture uneven.  Slightly trans-
lucent.  It occurs abundantly at Solfatera in
the neighbourhood of Vesuvius,  and in Ice-
Ltnd.—Jumcson.*
  * Sulphur.  A simple  inflammable body,
of great importance in chemistry and the
arts.  To the properties above mentioned,
we shall here add, that  its  fusing point is
about 220° !•'>, before which temperature, it
begins Xm evaporate.  At 560*, it takes fire
in the open air,  and bums with a pale blue
flame.  When kept melted in an open ves-
sel for some time, at about 300° F., it become*
thick and viscid; and if it  be then poured
into a basin of water, it appeal's of a red co-
lour, and ductile like wax.  In this state, it
is used for taking impressions of seals or
medals.  Its sp. gr. is 8aid to  be increased
from 1.99  to 2.325.  This change  is not
owing to  oxidation, for it takes place in
close vessels.
   When a roll of sulphur is suddenly seized
in a warm hand, it crackles, and sometime!
falls in pieces.   This is  owing to the  une-
qual action of heat, on a body which  con-
ducts that power slowly, and which has lit-
tle cohesion.  If a mass of sulphur be melt-
ed in a crucible, and after the surface begins
to concrete, if the liquid  matter below be al-
lowed to run out, fine acicular cr\ stals of
sulphur will be obtained.
   Sulphur is insoluble in  water; but in small
quantity  in alcohol  and ether, and  more
largely in oil
   Sulphur  combines  with oxygen  in  four
definite  proportions, constituting an inter-
esting series of acids,  See Acid  (Swlpuu-
ric )
   From  these combinations it is inferred,
that the prime equivalentof sulphur is 2; and
the density  of its vapour  is 1.111 = that
of oxygen gas.
   Sulphur combines  readily with chlorine.
This compound was first made hy Dr. Thorn-
son,  who passed  chlorine gas through flow-
ers  of sulphur.   It may  be made more ex-
peditiously by heating sulphur  in a  retort
containing chlorine.  The sulphur and chlo-
rine  unite,and form a fluid substance, which
is volatile, below  200° F.,  and distils into the
cold  part of the  retort.  This substance,
seen by reflected light, appears of a red co-
lour, but is yellowibh-green when seen by
transmitted light.  It smokes when exposed
to air, and has an odour somewhat resemb-
ling that of sea-weed, but much stronger;
it affects the eyes like the  smoke of  peat.
Its taste is acid, hot, and  bitter.  Ls sp. gr.
i>  1.7.
   It does not redden  perfectly dry paper
tinged with litmus; when  it is agitated in con-
tact  with water,  the water  becomes cloudy
from the appearance of sulphur, and strong-
ly acid, and it is  found to  contain oil  of vi-
triol.
   According to  Sir H.  Davy's experiments,
10 grains of pure sulphur absorb nearly 30
cubic inches of  chlorine; so that the com-
pound contains about 2. sulphur to 4.5 chlo-
rine, or a prime  equivalent of each.
   The compound formed in the manner
above described, cannot be made to unite to
more chlorine; but it can dissolve a  consi-
derable i- rtion of sulphur by heat, aud be-
comes of a tawny-yellow  colour. 
SUL                                  SUL
  Iodide of sulphur is  easily formed by
mixing the two ingredients in a glass tube,
and exposing them to such a heat as melts
the sulphur.  It is grayish-black,  and  has
a radiated structure like that of sulphuret
of antimony.  When distilled with  water,
iodine is disengaged.
  Sulphur and hydrogen combine.  Their
union may be effected, by causing sulphur
to sublime  in dry  hydrogen in a  retort.
There is no change of volume; but  only
a part of the hydrogen can be united with
the sulphur in this mode of operating.
  The usual way of preparing sulphuretted
hydrogen, is to pour a dilute sulphuric or
muriatic acid,  on the black sulphuret of
iron or antimony in a retort. For accurate
experiments, it should  be collected over
mercury. It  takes fire when a lighted
taper is brought  in contact with it,  and
burns with  a pale blue flame,  depositing
sulphur.  Its smell  is extremely fetid, re-
sembling that of rotten eggs.   Its taste is
sour.  It reddens vegetable blues.  It is ab-
sorbable by water,  which takes more than
an equal volume of  the gas. Its sp. gr. ac-
cording to MM. Gay-Lussac and Thenard,
is to that of air, 1.1912  to  1.0.  From Sir
H. Davy's experiments, it would appear to
be a little less, but he is inclined to adopt
the results of the French chemists, rather
than his own, as  their  gas was  weighed
in larger quantity, and dried.  Notwith-
standing this preference of other experi-
ments to his own, we must prefer a num-
ber nearer  to Sir H. Davy's than M. Gay-
Lussac's. Its true sp. gr. is 1.1805. 100 cu-
bic inches weigh 36.006 gr.; and it consists
of 1 volume vapour of sulphur = 1.1111.
-+-  1  volume of hydrogen =  0.0694 =
1.1805; or a prime  equivalent of each =
2.125.  If platina wires  be  ignited in it, by
the voltaic apparatus, it is  rapidly decom-
posed.  Sulphur is deposited, and  an equal
volume of hydrogen remains.   The same
change is effected more slowly by the elec-
tric spark.
  Of  all the gases, sulphuretted hydrogen
is perhaps the most deleterious to animal
life.  A greenfinch, plunged into air, which
contains only ttoTT of its volume, perishes
instantly. A dog of middle  size  is  de-
stroyed in air that  contains 7g^'  and a
horse would fall a victim to an atmosphere
containing^-
  Dr. Chaussier proves, that to kill an  ani-
mal, it is sufficient to make the sulphuret-
ted hydrogen gas act on the surface of its
body, when  it is absorbed by the inhalants.
He "took a bladder having  a stop-cock at
one end, and at the  other an opening,  into
which he introduced the body of  a rabbit,
leaving its head outside, and securing the
bladder air-tight round the neck by adhe-
sive plaster.  He then sucked the air out
   Vol. II.
of the bladder, and replaced it by sulpha-
retted hydrogen gas.   A young animal in
tliese circumstances, usually perishes in
in 15 or 20 minutes. Old rabbits resist the
poison much longer.
  When potassium or sodium is heated,
merely to fusion,  in contact with sulphu-
retted hydrogen, it becomes luminous,  and
burns with extrication of hydrogen,  while
a  metallic sulphuret  remains, combined
with sulphuretted hydrogen, or a sulphu-
retted hydrosulphuret.
  Sulphuretted hydrogen  combines with
an equal volume of ammonia;  and unites
to alkalis and oxides, so that it has all the
characters of an acid.   These  compounds
are called hydrosulphurete.
  All the hydrosulphurets, soluble in water,
have an acrid and bitter taste, and when in
the liquid state, the odour of rotten  eggs.
All those which are insoluble,  are, on the
contrary, insipid and without smell. There
are  only two  coloured hydrosulphurets,
that of iron, which is  black, and of anti-
mony, which is chesnut-brown.
  All the hydrosulphurets are decomposed
by the action of fire.   That of magnesia
is transformed into sulphuretted hydrogen
and oxide of  magnesium; those of potash
and soda, into sulphuretted hydrogen, hy-
drogen, and sulphuretted alkalis; those of
manganese, zinc, iron,  tin, and antimony,
into water and metallic sulphurets.
  When we put in contact with the air, at
the  ordinary  temperature, an aqueous so-
lution of a hydrosulphuret, there results,
in the space of some days, 1st, water,  and
a  sulphuretted hydrosulphuret, which is
yellow and soluble; 2d, water,  and  a  co-
lourless hydrosulphite, which,  if its base
be  potash, soda,  or ammonia, remains in
solution in the water; but which falls down
in acicular crystals, if its base  be barytes,
strontia, or lime.
  The acids in  general combine with  the
base ofthe hydrosulphurets, and disengage
sulphuretted  hydrogen with a lively ef-
fervescence,  without   any  deposition of
sulphur, unless the acid be in excess,  and
be capable, like the nitric and nitrous acids,
of yielding a portion of its oxygen to  the
hydrogen of the sulphuretted hydrogen.
  The hydrosulphurets of potash,  soda,
ammonia, lime, and magnesia, are prepared
directly, by transmitting an excess of  sul-
phuretted hydrogen  gas,  through  these
bases, dissolved or diffused in water.
  The composition of the hydrosulphurets
is such, that the hydrogen of the sulphu-
retted hydrogen, is to the oxygen of  the
oxide in the same ratio  as in water. Hence,
when we calcine  the  hydrosulphurets of
iron, tin, &c. we convert them  into water
and sulphurets.
  Hydrosulphuret of potash crystallizes in
                      38 
SUL
SUL
 four-sided prisms, terminated by four-sided
 pyramids.  Its taste  is  acrid and bitter.
 Exposed to the air, it attracts humidity,
 absorbs  oxygen, passes  to the state of a
 sulphuretted hydrosulphuret, and finally
 to that of a hydrosulphite. It is extremely
 soluble in water. Its solution in this liquid
 occasions a perceptible refrigeration.  Sub-
 jected to heat, it evolves much sulphuret-
 ted hydrogen, and the hydrosulphuret pas-
 ses to the state of a sub-hydrosulphuret.
  Hydrosulphuret of soda  crystallizes  with
 more difficulty than the preceding.
  Hydrosulphuret of ammonia is obtained by
 the direct union of  the two gaseous con-
 stituents in a glass  balloon, at a low tem-
 perature.  As  soon as the gases  mingle,
 transparent white or yellowish crystals are
 formed.   When a mere solution of this hy-
 drosulphuret  is wished  for  medicine or
 analysis, we pass a current of sulphuretted
 hydrogen through  aqueous  ammonia till
 saturation.
  The pure hydrosulphuret is white, trans-
 parent, and crystallized in needles or fine
 plates.  It is very volatile.  Hence, at or-
 dinary temperatures, it gradually sublimes
 into the upper part of the phials in which
 we preserve it.  We may also by the same
 means separate it from the yellow sulphu-
 retted hydrosulphuret, with which  it is oc-
 casionally mixed.   When exposed to  the
 air, it absorbs  oxygen, passes to the state
 of a sulphuretted hydrosulphuret,  and be-
 comes yellow.   When it contains an excess
 of ammonia, it dissolves speedily in water,
 with the production of a very considerable
 coal.
  Sub-hydrosulphuret of barytes is prepared
 by dissolving,  in five or six parts of boiling
 water, the sulphuret of the earth obtained
 by  igniting the sulphate with  charcoal.
 The solution, being filtered while hot, will
 deposite, on cooling, a multitude of crystals
 which must be drained, and speedily dried
 by pressure between  the folds of  blotting
paper. It crystallizes in white scaly plates.
 It is much more soluble in hot than in cold
water.  Its solution  is colourless, and capa-
ble of absorbing, at the ordinary tempera-
ture, a very large quantity of sulphuretted
hydrogen.
  Sub-hydrosulphuret of strontites crystalli-
 zes in the same manner as the preceding.
 The crystals obtained in the same way must
 be dissolved in water; and the solution be-
 ing exposed to a stream of sulphuretted
 hydrogen, and then concentrated  by eva-
 poration in a retort, will afford, on cooling,
 crystals of pure sub-hydrosulphuret.
  Hydrosulphurets  of lime and magnesia
 have  been obtained only in aqueous solu-
 tions. The metallic  hydrosulphurets of any
 practical importance are  treated of under
 their respective metals.
  When we expose  sulphur to the action of
 a solution of a hydrosulphuret, saturated
 with sulphuretted hydrogen, so much more
 sulphuretted hydrogen  is evolved, as the
 temperature is more elevated.  But when
 the solution of hydrosulphuret, instead of
 being saturated,  has a sufficient excess of
 alkali, it evolves no perceptible quantity of
 sulphuretted hydrogen, even  at a boiling
 heat; although it dissolves as much sulphur
 as in its state of  saturation.   It hence fol-
 lows, 1st, That sulphuretted hydrogen, sul-
 phur,* and the alkalis, have the property of
 forming very variable triple combinations;
 2d, That all these combinations contain less
 sulphuretted hydrogen  than the hydrosul-
 phurets; and, 3d, That the quantity of sul-
 phuretted hydrogen is inversely as the sul-
 phur they contain, and reciprocally. These
 compounds  have been called, in  general,
 sulphuretted  hydrosulphurets; but  the
 name of hydrogenated  sulphurets  is more
 particularly given  to  those combinations
 which are saturated with sulphur at a high
 temperature,  because,  by treating them
 with acids, we precipitate a peculiar com-
 pound of sulphur and hydrogen, of which
 we shall now treat.
  This compound of hydrogen  and  sulphur,
 the proportions of  the  elements of which
 have not yet been accurately  ascertained,
 is also called a hydruret of sulphur.  It is
 formed  by putting  flowers of sulphur in
 contact with  nascent sulphuretted hydro-
gen.  With this view, we take an  aqueous
 solution of the hydrogenated  sulphuret of
potash,  and pour it gradually into liquid
muriatic acid, which seizes the potash, and
 forms a soluble salt,  whilst the sulphur and
 sulphuretted hydrogen unite, fall down to-
 gether, collecting by degrees at the bottom
 of the vessel, as a dense oil does in water.
 To preserve this hydruret of  sulphur, we
 must fill with it  a phial having a ground
 stopper, cork it, and keep it  inverted in a
 cool place.  We may  consider this sub-
 stance either as a combination of  sulphur
 and  hydrogen, or of sulphur  and  sulphu-
 retted hydrogen; but its properties, and the
 mode of obtaining it, render the latter the
 more probable opinion.  The proportion of
 the constituents is not known.
  The most interestingof the hydrogenated
 sulphurets is that of ammonia. It  was dis-
 covered  by the Hon. Robert  Boyle, and
 called his fuming liquor.  To prepare it,
 we take one part of muriate  of ammonia
 and of pulverized quicklime, and half a part
 of flowers of sulphur.  After mixing them
 intimately, we introduce the mixture into
 an earthen or glass retort, taking care that
 none of it remains  in  the neck.   A  dry
 cooled receiver is connected  to the retort
 by means of a long adopter-tube. The heat
 must be urged slowly  almost to redness.
 A yellowish liquor condenses in the receiv.
 er,  which is to be put into a phial  with its 
SUM
SWE
  own weight of flowers of sulphur, and agi-
  tated with it seven or eight minutes.  The
  greater  part of the sulphur is dissolved,
  the colour ofthe mixture deepens remark-
  ably, and becomes thick,  constituting the
  hydrogenated sulphuret.
    The distilled liquor diffuses, for  a long
  time, dense vapour in ajar full of oxygen
  or common air; but scarcely any in azote
  or hydrogen; and the dryness or humidity
  ofthe gases makes no difference in  the ef-
  fects.  It is probably owing to the oxygen
  converting the liquor into  a hydrogenated
  sulphuret, or perhaps to the state of sul-
  phite, that the vapours appear.
    Hydrogenated sulphurets are frequently
  Called hydroguretted sulphurets.
    Sulphur combines  with carbon, forming
  an interesting  compound, to which  the
  name of sulphuret of carbon is sometimes
  given.   I have described it under the title
  Carburet of Sulphur.  For the com-
  binations of sulphur and phosphorus, see
  the latter article.*
    • Sulphuretted Chyaxic Acid. See
  Acid (Sulphuro-Prussic).*
    •Sulphuric Acid.  See Acid  (Sul-
  phuric).*
    • Sulphurous Acid. See Acid  (Sul-
  phurous).*
    Sumach.  Common sumach (rhus coria-
 ria) is a  shrub that grows  naturally  in Sy-
 ria, Palestine, Spain,  and Portugal.   In the
 two last, it is cultivated with great care.
 Its shoots are cut down every year quite to
 the root,  and, after being  dried, they are
 reduced to powder by a mill, and thus pre-
 pared for the purposes of dyeing and tan-
 ning. The sumach cultivated in the neigh-
 bourhood of Montpellier, is called ridoul,
 or roudou.
   Mr. Hatchett found, that an ounce con-
 tains about 78 or 79 grains  of tannin.
   Sumach acts on a solution of silver just
 as  galls do; it reduces the silver to its me-
 tallic state; and the reduction is favoured
 by the action of light.
   Of all astringents sumach bears the great-
 est resemblance to galls. The precipitate,
 however,  produced in solutions of iron  by
 an  infusion of it is less in quantity than
 what is obtained by  an equal  weight of
 galls; so that in most cases it may be sub-
 stituted for galls, the price of which is con-
 siderable, provided we proportionally in-
 crease its  quantity.
  Sumach alone gives a fawn colour,  incli-
 ning to green; but cotton stuffs, which have
 been impregnated with printer's mordant,
 that is, acetate of alumina, take a pretty
 good and very durable yellow.  An incon-
 venience is experienced in  employing su-
 mach in this way, which arises from the
fixed nature of its colour; the ground of
the stuff does not lose its colour by expo-
  sure on the grass, so that it becomes ne-
  cessary to impregnate all the stuff with dif-
  ferent mordants, to vary the colours, with-
  out leaving any part of it white.
    Supersalt.  A compound of an acid
  and base, in which the acid is in excess.
  See Subsalt.
    *Surturbrand.  Fibrous brown c oal,
  or bituminous wood, so called in Iceland,
  where it occurs in great quantities.*
    * Swamp Ore.  Indurated bog iron ore.*
    Sweat.  When the temperature of the
  body is  much increased,  either  by being
  exposed to a hot atmosphere, or by violent
  exercise, the perspired vapour not only in-
  creases in quantity, but even appears in  a
  liquid form.  This is known by the name
  of sweat.
    Beside water, it cannot be doubted, that
  carbon is also emitted from the skin; but in
  what state, the experiments hitherto made
  do not enable  us to decide.  Mr. Cruick-
  shanks found, that the air ofthe glass ves-
  sel in which his hand and foot had been
  confined for an  hour, contained  carbonic
  acid gas; for a candle burned dimly in it,
  and it rendered lime-water turbid. And Mr.
  Jurine found, that air which had remained
  for some time  in  contact with the skin,
  consisted  almost entirely of carbonic acid
  gas.  The same conclusion may be drawn
  from the experiments of Ingenhousz and
  Milly.  Trousset has lately observed, that
  air was separated copiously from a patient
  of his while bathing.
   Beside  water  and carbon,  or  carbonic
  acid gas, the skin  emits also a particular
  odorous substance.  That every aninal has
  a peculiar smell, is  well known: the dog
 can  discover his master,  and even trace
 him to a distance by the scent.   A dog,
 chained up several hours after his master
 had set out on a journey of some hundred
 miles, followed his footsteps by the  smell.
 But it is needless to  multiply instances of
 this fact,  they are too well known to every
 one. Now this smell must  be owing to
 some peculiar matter which is  constantly
 emitted; and this matter must differ some-
 what either  in  quantity or  some  other
 property, as we  see, that  the  dog easily
 distinguishes the individual by means  of
 it. Mr. Cruickshanks has made it probable
 that this matter is an oily substance; or at
 least, that there is an oily substance emit-
 ted by the skin. He wore repeatedly, night
 and day for a month, the same under waist-
 coat of fleecy hosiery, during the hottest
 part of the summer.  At the end of this
time he always found an oily substance ac-
 cumulated in considerable masses on the
 nap of the inner surface of the  waistcoat,
in the form of black tears.  When rubbed
on paper,  it rendered it transparent, and
hardened on it like grease. It burned with 
TAL
TAL
a white flame, and left behind it a charrv
residuum.
  Berthollet has observed the perspiration
acid;  and he  has concluded, that the acid
which is present is the phosphoric; but this
has not been  proved.   Fourcroy and Vau-
quelin have  ascertained, that  the scurf
which collects  upon the skins  of horses,
consists chiefly of phosphate of lime,  and
urea is even sometimes mixed with it.
  According  to Thenard,  however, who
has lately endeavoured more particularly
to ascertain this point, the acid contained
in sweat is the acetous; which, he likewise
observes, is the only free acid contained in
urine and in milk, this acid existing in both
of them when quite fresh.  His account of
his examination of itis as follows:
  The sweat is more or less copious in dif-
ferent individuals;  and its quantity is per-
ceptibly in the inverse ratio of that ofthe
urine. All other circumstances being simi-
lar, much more  is produced during diges-
tion than during repose.  The maximum of
its production appears  to  be  twenty-six
grains and two-thirds in a minute, the mini-
mum  nine grains troy weight.  It  is much
inferior, however, to the pulmonary trans-
piration; and there  is likewise a great dif-
ference between their  nature and manner
of formation.   The one is the product of a
particular secretion, similar in some sort to
that of the urine; the other, composed of a
great deal of water and  carbonic acid, is
the product of a combustion gradually ef-
fected by the atmospheric air.
  The sweat, in a healthy state, very  sen-
sibly  reddens litmus paper or infusion.  In
certain diseases, and particularly in putrid
fevers, it is alkaline; yet  its taste is always
rather saline, and more similar to that of
salt than acid. Though colourless, it stains
linen. Its smell is peculiar, and insupport-
able when it is concentrated, which is the
case in particular during distillation.  But
before he speaks of the trials to which he
subjected it,  and of which he had occasion
for a great quantity, he describes the me-
thod  he adopted for procuring it, which
was similar to that of Mr. Cruickshanks.
   Human sweat, accordingto M. Thenard,
is formed of a great deal of water;  free
acetous acid; muriate of soda; an atom of
phosphate of lime, and oxide of iron; and
an inappreciable quantity of animal matter,
which approaches much nearer to gelatin
than to  any other substance.
   * Swinestone.   A variety of compact
lucullite, a sub-species of limestone.*
   Sylvanite.   Native tellurium.
   Sylvius  (Salt of),  or (Febrifuge
Salt or).   Muriate of potash.
   Synovia. Within the capsular ligament
of the different joints ofthe body, there is
contained a peculiar liquid, intended evi-
dently to  lubricate the parts, and to facili-
tate their motion.  This liquid is known
among anatomists by the  name of synovia.
   From the analysis of M. Margueron, it
appears, that synovia is composed of the
following ingredients:
           11.86 fibrous matter
            4.52 albumen
            1.75 muriate  of soda
             .71 soda
             .70 phosphate of lime
           80.46 water
100.00
T
* mABULAR  SPAR, or Table  Spar
   JL   The  schaalstein of Werner,  and
prismatic augite of Jameson.
  Colour grayish-white.  Massive, and in
angular-granular   concretions.    Shining
pearly.  Cleavage double.   Fracture splin-
tery. Translucent. Harder than fluorspar,
but not so hard as apatite. Brittle. Sp. gr.
S.2 to 3.5.  Its constituents are, silica 50,
lime 45, water  5.—-Klaproth.  It occurs in
primitive rocks, at Orawicza in  the Bannat
of Temeswar, where it is associated  with
brown garnets.*
   * Tacamahac   A  resin, having the
aroma of musk, and soluble in alcohol.*
   *  Talc   Of this  mineral,  Professor
Jameson's sixth sub-species of rhomboidal
mica, there are two kinds; common  talc,
and indurated talc.
   1. Common talc. Colour greenish-white.
Massive, disseminated, in plates, imitative,
and sometimes crystallized in small six-
sided tables, which are druses.  Splendent,
pearly,  semi-metallic.   Cleavage  single,
with curved folia.  Translucent.  Flexible,
but not elastic.  Yields to the  nail.  Per-
fectly sectile.  Feels very greasy.  Sp. gr.
2.77.  It whitens, and at length  affords a
small globule of enamel, before the blow-
pipe.  Its constituents are, silica 62, mag-
nesia 27,  alumina  1.5,  oxide  of iron 3.5,
water 6.—Vauquelin.  Klaproth found 2.75
of potash in 100 parts.   It occurs in beds
in mica-slate and clav-slate. It is found in
Aberdeenshire, Banffshire, and Perthshire.
The finest specimens come from Saltzburg,
the Tyrol, and St.  Gothard.  It is an ingre-
dient in rouge for the toilette, along with
carmine and benzoin  This cosmetic com-
municates a remarkable degree of softness 
TAN                               TAN
to the skin, and is not injurious.  The flesh
polish is given to gypsum figures, by rub-
bing them with talc.
  2. Indurated tale, or talc-slate.  Colour
greenish-gray.  Massive.  Fragments tabu-
lar.   Translucent  on  the  edges.  Soft.
Streak white.  Rather sectile.  Easily fran-
gible.   Not flexible.  Feels greasy.  Sp.
gr. 2.7 to 2.8.  It occurs in primitive moun-
tains, where it forms beds in clay-slate and
serpentine.   It is found in   Perthshire,
Banffshire, the Shetland Islands, and abun-
dantly on the  Continent.  It  is employed
for drawing lines  by carpenters, tailors,
hat-makers, and glaziers.—Jameson*
   •  Talcite.  Nacrite  of Jameson, and
earthy  talc of Werner.   Colour greenish-
white.   It consists of scaly parts.  Glim-
mering, pearly.  Friable. Feels very greasy.
Soils.  It melts easily before the blow-pipe.
Its constituents  are, alumina  81.75, mag-
nesia 0.75,  lime 4, potash 0.5, water 13.5.
—John. This is a very  rare  mineral, oc-
curring in veins, with sparry ironstone and
galena,  in  the mining  district of Frey-
berg.*
   • Tallow.  See Fat.*
   * Tamarinds.  The  pulp consists, ac-
cording to Vauquelin, of bitartrate of pot-
ash 300, gum 432, sugar 1152, jelly 576,
citric acid 864, tartaric acid 144, malic acid
40,  feculent matter  2880, water 3364; in
9752 parts.*
   Tannin.  This, which is one ofthe im-
mediate principles of vegetables, was first
distinguished  by Seguin from the gallic
acid, with  which it had been confounded
under the name of the astringent  principle.
He gave it the name of tannin, from its use
in the tanning of leather; which  it  effects
 by its characteristic property, that of form-
 ing with gelatin a tough insoluble matter.
   It may be  obtained  from vegetables by
 macerating them in cold water; and preci-
 pitated from  this solution, which contains
 likewise gallic acid and  extractive matter,
 bv hyperoxygenized muriate of tin.  From
 this precipitate, immediately diffused in a
 large quantity of water, the oxide of tin
 may be separated by sulphuretted  hydro-
 gen gas, leaving the tannin in solution.
   Professor Proust has since recommended
 another method, the precipitation of  a de-
 coction of galls by powdered  carbonate of
 potash, washing  well  the greenish-gray
 flakes that fall down, with cold water, and
 drying  them in a stove.  The precipitate
 grows brown in the air, becomes brittle and
 shining like a resin, and yet remains soluble
 in hot  water.  The tannin in  this state, he
 says, is very pure.
    Sir H. Davy, after making  several expe-
 riments on different methods of ascertain-
 ing the quantity of tannin in  astringent in-
 fusions, prefers for this  purpose, the com-
 mon process of precipitating the tannin by
gelatin; but he remarks, that the tannhtapf
different vegetables requires different pro-
portions of gelatin  for its saturation; and
that the quantity of precipitate obtained is
influenced by the degree in which the so-
lutions are concentrated.
   M. Chenevix observed, that coffee berries
acquired by roasting the property of preci-
pitating gelatin; and Mr. Hatchett has made
a number of experiments, which show, that
an artificial tannin,  or substance having its
chief property, may be formed, by treating
with nitric acid,  matters containing char-
coal.  It  is  remarkable that  this tannin,
when prepared from vegetable substances,
as dry charcoal of wood, yields, on combus-
tion, products analogous to those of animal
matters.  From his experiments it would
seem,  that tannin is, in reality, carbonace-
ous matter combined with oxygen; and the
difference in the proportion of oxygen may
occasion the differences in the tannin pro-
cured from different substances, that from
catechu appearing to contain most.
   Bouillon Lagrange  asserts, that tannin
by absorbing oxygen is converted into gal-
lic acid.
   It is not an unfrequent practice, to admi-
nister medicines containing tannin in cases
 of debility,  and  at the same  time to  pre-
 scribe gelatinous food as nutritious.   But
 this is evidently improper, as the tannin,
 from its chemical properties, must render
 the gelatin indigestible. For  the chief use
 of tannin, see the following article.
   * According to Berzelius, tannin consists
 of hydrogen 4.186 + carbon 51.160 -f- oxy-
 gen 44.654.  And  the tannate  of lead  is
 composed of
     tannin,         100      26.923
     oxide of lead,   52      14.
 But there is much uncertainty concerning
 the definite neutrality of this  compound.*
   Tanning. The several kinds of leather
 are prepared from  the skins of animals ma-
 cerated for a long time with lime and water,
 to promote the separation of the hair and
 wool,  and of the  fat and fleshy parts,  in
 which recourse is also had to the assistance
 of mechanical pressure, scraping, and the
 like.   The skin, when thus deprived of its
 more  putrescible part, and brought consi-
 derably toward the state of mere fibre, is
 tanned by maceration  with certain  astrin-
 gent  substances, particularly the bark  of
 the oak-tree.
   The hide consists almost wholly of gela-
 tin, and all that is  necessary is, to divest  it
 of  the hair, epidermis, and any flesh or fat
 adhering to  it.  This  is commonly  done,
 after  they have been soaked in water some
 time,  and handled or trodden to cleanse
 them  from  filth,  by immersing  them  in
 milk  of lime. Some, instead of lime, use
 an  acescent infusion of barley or rye-meal,
 or  spent tan; and others recommend watjei- 
TAN
TAN
  S'dulated  with sulphuric  acid.  Similar
   dulous waters are  afterward employed
for raising  or swelling the hide, when this
is necessary.
  The skins thus prepared, are  finally to
undergo what  is properly  called the tan-
ning.  This is  usually done  by  throwing
into  a pit, or cistern made  in the ground,
a quantity  of ground oak-bark, that has
already been used, and on this  the  skins
and fresh bark in alternate layers, covering
the whole with half a foot of tan, and tread-
ing it well down.  The tanning may be
accelerated by adding a little water.
  As it is  a long time before the  hide is
thoroughly tanned in this  mode, at least
many months,  during which the bark  is
renewed three or four  times; M.  Seguin
steeps the skin in a strong  infusion of tan,
and assists its action by  heat.  Chaptal ob-
serves,  however, that this requires an ex-
tensive apparatus, for preparing the liquor,
and the skins: the leather imbibes so much
water, that it remains spongy a long time,
and wrinkles in drying; and itis extremely
difficult so  to arrange the hides in a copper,
as to keep them apart from  each other, and
free  of the sides of the vessel.
  The following account  of M. Seguin's
practice, was transmitted to England in the
year 1796:—
  To tan a skin is to take away its putres-
cent quality, preserving, however, a certain
degree of pliability. This is effected by in-
corporating with the skin particles ofa sub-
stance, which  destroys  their tendency to
putrefaction.
  The operations relating  to tanning are
therefore of two kinds:—the first is merely
depriving the  skin of those parts,  which
would oppose  its preservation,  or which
adhere to it but little,  such as hair and
flesh; the  other consists in incorporating
with it a substance, which shall prevent its
putrefying.
   The operations of the first kind are tech-
nically termed, unhairing and fleshing; the
operations of the  second kind  belong  to
tanning, properly so called.
   Fleshing is an operation merely mecha-
nical: unhairing is  a  mechanical operation
if performed  by shaving; or a chemical
operation, if effected by dissolution  or de-
composition of the substance, which con-
nects the hair  with the  skin.
   According to the  ancient method, the
dissolution of  this substance was  effected
by means of lime; the decomposition, either
by the  vinous  fermentation of barley,  by
the  acetous fermentation  of oak-bark, or
by the  putrid  fermentation produced by
 piling the  hides one upon  another.
   Unhairing by means of lime would often
 take 12 or 15  months;  this operation with
 barley, or  the acetous part of tan, could not
 be performed  in less than two months.
  The slowness of these operations, which
the experiments of Seguin have shown may
be finished in a few days, and in  a more
advantageous  manner,  by means of the
same substances, proves, that the nature
of those operations was not understood by
those who  performed them.   Those of
tanning, properly so called, were as little
known, as the details  we are  about giving
will  prove,  which we compare with the
least improved routine now in practice.
  Whatever the method of unhairing was,
the mode of tanning was always the same,
for skins unhaired with lime, or those pre-
pared with barley or tan.
  This  mode of operating   would take
eighteen months or two years, often three
years, when it was wished to tan the hides
thoroughly.
  Among the substances for tanning, gall-
nut,  sumach, and the bark of oak, to which
may be added catechu, appear the most
proper, at least, in the present state of our
knowledge. In the middle departments of
France, oak-bark is preferred, because it
is the cheapest  and most  abundant sub-
stance.  To use  it, it is first ground to
powder; then, according  to the old mode,
it is  put into large holes dug in the  ground,
which are  filled by  alternate layers  of
ground bark and unhaired hides.
  As the principle  which effects  the tan-
ning cannot act in the interior of the skin,
unless carried in by some liquid in which
it is  first dissolved, tanning is not produ-
ced  by the immediate action of the pow-
dered bark upon the skin, but only by the
action of the  dissolution of  the  tanning
principle originally contained in the bark.
The tan therefore has the tanning proper-
ty only when wetted so much as not to ab-
sorb all  the water  thrown on it.   But as
tanners put in their vats only a small por-
tion of water compared  to what would be
necessary to deprive the bark  of all  the
tanning principle which it contains,  the
bark put into  the  vats  preserves, when
taken out,  a portion  of  its tanning princi-
ple.
   This waste is not the  only disadvantage
of the old modes of proceeding; they are,
besides, liable never to produce in the skina
a complete saturation with the tanningprin-
ciple. For as the property of attraction is
common to all bodies, according to the dif-
ferent degree of saturation, the water con-
taining in solution a certain quantity of the
tanning principle, will not part, to a fixed
weight of skins, with as much as the same
 quantity of water will, in which a greater
 quantity of the principle is dissolved.
   As the water, which in the old manner
 of proceeding is in  the vats, can contain
 but a small portion of the tanning princi-
 ple, owing to the nature of the operation,
 it can give but a small  portion of it to the 
TAN                                TAN
skin, and even this it parts with by slow
degrees.  Hence, the slowness in the tan-
ning of skins according to the old method,
which required two whole years, and some-
times three, before a skin was well tanned
to the centre.  Hence  also, the imperfec-
tion of  skins tanned by that method; an
imperfection resulting from  the non-satu-
ration of the tanning principle, even when
it had penetrated the centre.
  The important desideratum was, there-
fore, to  get  together, within  a  small com-
pass,  the tanning principle, to increase its
action, and produce in the hide  a complete
saturation in a much shorter time than that
necessary for the incomplete tanning pro-
duced in vats.  But, first of all, it was ne-
cessary to analyze the skin, analyze the
leather, and analyze the oak-bark.  The
principles of these three substances were
to be insulated, and  their action upon one
another determined, the influence of their
combination upon that action known, and
the circumstances most productive of its
greatest action found out.
  Seguin, by following this method, has
determined:—
  1. That the skin deprived of flesh and
hair, is  a substance,  which can  easily, by a
proper process, be entirely converted into
an animal jelly (glue).
  2. That a solution of this last mentioned
substance, mixed with a solution of tan,
forms immediately an imputrescible and in-
dissoluble compound.
  3. That the solution of tan is composed
of  two very distinct  substances;  one  of
which precipitates the solution of glue,
and which is the true tanning substance;
the other, which  precipitates sulphate of
iron, without precipitating the  solution of
glue, and which  produces only the neces-
sary disoxygenation of the skin, and of the
substance which  connects the hair to the
skin.
  4. That the operation of tanning is not
a simple combination of the skin with the
principle which precipitates the glue, but
a combination  of that principle with the
skin  disoxygenized  by  the  substance,
which in the dissolution of tan  is found to
precipitate  the  sulphate of  iron; so that
every substance proper for tanning  should
possess  the properties of precipitating the
solution of glue, and of precipitating the
sulphate of iron.
  5. That the operation of tanning consists
in swelling  the  skins by means of an aci-
dulous principle; to disoxygenize, by means
of the  principle which in  the  solution  of
bark precipitates the solution of sulphate
of iron, that substance which connects the
hair to the skin, and thus produce an easy
unhairing;  to disoxygenize  the skin by
means of the same principle, and to bring
it by  this disoxygenation  to the  middle
state between glue  and skin; and then t»
combine with it, after this disoxygenation,
and while it is  in this middle state, that
particular substance in oak-bark, as well
as in many other vegetables, which is found
to precipitate the  solution  of  glue,  and
which is not, as has been hitherto conceiv-
ed, an astringent substance.
   Agreeably to these discoveries, there
only remains, in order to tan speedily and
completely, to  condense the tanning prin-
ciple so as to accelerate its action. Seguin,
to effect this, follows  a very simple pro-
cess. He pours water upon the powdered
tan, contained in an apparatus nearly simi-
lar to that made use of in saltpetre works*
This water, by going through  the  tan,
takes from it a portion of its tanning prin-
ciple, and by successive nitrations dissolves
every time an additional quantity of it, till
at last the bark rather tends to deprive it
of some than to give up more. Seguin suc-
ceeds in bringing tliese solutions to such a
degree of strength, that, he says, he can,
by taking proper  measure, tan calf-skin in
24 hours, and  the strongest ox-hides in
seven or eight days. These solutions con-
taining  a great quantity of the tanning
principle, impart to the skin as much of it
as it can absorb; so that it can then easily
attain a complete saturation of the princi-
ple,  and produce leather of a quality much
superior to  that of  most countries famous
for their leather.
   On the above I have only to remark, that
every new art or considerable improvement
must unavoidably be  attended with many
difficulties in the establishment of a manu-
factory in the large way.  From private in-
quiry I find, that this also has its difficul-
ties, which have hitherto prevented its be-
ing carried into full effect in this  country.
Of what nature these may be 1 am not de-
cidedly informed, and mention them in this
place only to prevent manufacturers from
engaging  in an undertaking of this kind,
without cautious inquiry.
   M. Desmond has  recommended, to satu-
rate water with tannin, by affusion on  suc-
cessive portions of oak-bark, or whatever
may be used; and when the bark will give
out no more tannin, to extract what gallic
acid still remains in it, by pouring on fresh
water.  To the latter, or acidulous liquor,
he adds one-thousandth part by measure of
sulphuric acid; and in this steeps the hide,
till the hair will come off easily  by scra-
ping. When raising is necessary, he steeps
the hide ten or twelve hours in water aci-
dulated with a five-hundredth part by mea-
sure  of sulphuric acid;  after which they
are to be washed repeatedly, and scraped
with  the  round knife.  Lastly, the hides
are to be steeped some  hours in a  weak
solution of  tannin,  then  a few days in a
stronger,  and this must be renewed as the 
TAR
TEA
 tannin is exhausted, till the leather is fully
 tanned.
   For the softer skins, as calves', goats',
 &c. he does not use the acid mixture, but
 milk of lime.
   Of substances used for tanning, Sir H.
 Davy observes, that 1 pound of catechu is
 nearly equal to 2i of galls, 3 of sumach,
 7i of the bark of the Leicester willow, 8$
 of oak-bark, 11 of the bark of the  Spanish
 chestnut, 18 of elm-bark, and 21 of com-
 mon willow-bark, with respect to the  tan-
 nin contained in them.   He observes  too,
 that leather  slowly tanned in weak infusi-
 ons of barks appears to be better in quali-
 ty,  being  both softer and  stronger than
 when tanned by strong infusions;  and he
 ascribes this to the extractive matter they
 imbibe.  This  principle, therefore, affects
 the quality of  the material employed in
 tanning; and galls, which contain  a great
 deal of tannin, make a  hard leather,  and
 liable to crack,  from  their deficiency of
 extractive matter.—Ann. de  Chim.—Philos.
 Trans.—Philos. Mag.—Chaptul's Chem.
   * Tantalum Ore.  See Ore of Tan-
 talum.*
   * Tantalum. The metal already treat-
 ed of under the name of Columbium.*
   Tarras, or Terras.   A volcanic earth
 used as a cement. It does not differ much
 in its principles from pouzzolana; but it is
 much more  compact,  hard, porous,  and
 spongy.  It is generally of a whitish-yellow
 colour,  and contains more heterogeneous
 particles, as spar, quartz, schoerl, &c.  and
 something more of a calcareous earth.  It
 effervesces with acids, is magnetic,  and fu-
 sible per se.  When  pulverized,  it serves
 as a cement, like pouzzolana.  It is found
 in Germany and Sweden.  See Lime.
   •Tartar.  See Acid (Tartaric).*
  Tartar is deposited on the sides of
 casks during the fermentation of wine:  it
.forms a lining more or less thick, which is
 scraped off.  This is called crude tartar,
 and is  sold in Languedoc from 10 to 15
 livres the quintal.
  All wines do  not afford  the same quan-
 tity of tartar. Neumann remarked, that the
 Hungarian wines left only a thin stratum;
 that the  wines  of France afforded more;
 and that the  Rhenish wines afforded  the
 purest and the greatest quantity.
  Tartar is distinguished  from  its colour
 into red and white: the first is afforded by
 red wine.
  Tartar is purified from an abundant ex-
 tractive principle, by processes which are
 executed at Montpellier and at Venice.
  The following is  the  process used at
 Montpellier:—The tartar  is dissolved in
 water, and suffered to crystallize by cool-
 ing.  The  crystals are then  boiled in ano-
 ther vessel, with the addition of five or six
 pounds of the white argillaceous earth of
 Murveil to each quintal of the salt.  After
 this boiling with the earth,  a very white
 salt is obtained by  evaporation,  which is
 known by the name of cream of  tartar, or
 the acidulous tartrate of potash.
   M. Desmarctz has informed us, that the
 process used at Venice consists,
   1. In drying  the tartar in iron boilers.
   2. Pounding  it, and dissolving it in  hot
 water, which,  by  cooling,  affords purer
 crystals.
   3. Redissolving these crystals  in water,
 and clarifying  the  solution by whites of
 eggs and ashes.
   The process of Montpellier is preferable
 to that of Venice.  The addition of  the
 ashes introduces  a foreign salt,  which al-
 ters the purity of the product. See Acm
 (Tartaric).
   T ah tar(Chalyb bated). This is pre-
 pared by boiling three parts of the super-
 tartrate of potash and two of iron filings
 in forty-six parts of water,  till the tartar
 appears to be  dissolved.  The  liquor is
 then filtered, and crystals are deposited on
 cooling, more of which are obtained  by
 continuing the evaporation.
   Tartar (Cream  of).   The  popular
 name of the purified supertartrate of pot-
 ash.
   Tartar (Crude).  The supertartrate
 of potash  in its natural state, before it has
 been purified.
   Tartar (Emetic). The tartrate of
potash and antimony,  See Antimony.
   Tartar of the teeth. The popular
name for the concretion that so frequently
incrusts the teeth, and which consists  ap-
parently of phosphate of lime.
  Tartar (Regenerated). Acetate of
 potash.
   Tartar (Salt of). The subcarbonate
 of potash.
   Tartar (Secret Foliated Earth
 of).  Acetate of potash.
  Tartar (Soluble).  Neutral tartrate
of potash.
   Tartar (Vitriolated). Sulphate of
potash.
  Tartarine.  The name given by Kir-
 wan to the vegetable alkali, or potash.
   Tartarous Acid.  See  Acid (Tar-
 taric).
  Tartrate.  A neutral compound ofthe
tartaric acid with a base.
  Tears.  That peculiar fluid,  which is
employed in lubricating the eye, and which
 is emitted in considerable quantities when
 we express grief by>weeping, is known by
 the name of tears.  For an accurate analy-
 sis of this fluid  we are indebted to Messrs.
 Fourcroy and Vauquelin.
   The liquid called tears  is transparent
 and colourless like water; it has scarcely
any smell, but its taste  is always  percepti-
bly salt.  Its specific gravity is somewhat 
TEL                                 TEL
greater than  that of distilled  water.   It
gives to paper stained with the juice ofthe
petals of mallows or violets as permanent-
ly green colour,  and  therefore contains a
fixed alkali.  It unites with water, whether
cold  or hot,  in  all proportions.   Alkalis
unite with it readily, and  render  it more
fluid.  The mineral acids  produce no ap-
parent  change upon  it.   Exposed to the
air,  this liquid  gradually evaporates, and
becomes  thicker.  When  nearly reduced
to a state  of dryness, a number of cubic
crystals form  in the midst of a kind of mu-
cilage. These crystals possess the proper-
ties of muriate of soda; but they tinge ve-
getable blues green, and therefore contain
an excess  of soda.  The mucilaginous mat-
ter acquires a yellowish colour as it dries.
   Tears are composed of the following in-
gredients:—
   1. Water,
   2. Mucus,
   3. Muriate  of  soda,
   4. Soda,
   5. Phosphate of lime,
   6. Phosphate of soda.
   The saline parts  amount only to about
0.01 of the whole, or probably not so much.
  Teeth.  The basis  of the  substance
that forms the teeth, like that of other
bones, (See Bone),  appears  to be phos-
phate of lime.  The  enamel, however, ac-
cording to Mr. Hatchett, diff'ers from other
bony substances in being destitute of car-
tilage: for raspings of enamel, when mace-
rated in dilutedacids, he found were wholly
dissolved;  while  raspings of bone,  treated
in the same manner, always left a  cartila-
ginous substance untouched.  See  Bone.
  •Telesia.  Sapphire.*
   Tellurium.  Muller  first  suspected
the existence of a new metal in the aurum
paradoxicum, or  problematicum, which has
the appearance of an  ore of gold,  though
very little  can be extracted from it.  Klap-
roth afterward  established its  existence,
not only in this, but in some other Transyl-
vanian ores, and named it tellurium.
   Pure tellurium is of a tin-white  colour,
verging to lead-gray, with a high metallic
lustre; of a foliated fracture, and very brit-
tle, so as to be easily  pulverized.   Its sp.
gr. 6.115.   It melts before ignition, requir-
ing a little higher heat than lead, and less
than antimony; and, according to  Gmelin,
is as volatile  as arsenic.  When  cooled
without agitation, its surface has  a crys-
tallized appearance.   Before the blow-pipe
on charcoal it burns with a vivid blue light,
greenish on the edges; and is dissipated in
grayish-white  vapours, of a pungent smell,
which condense into a white oxide.  This
oxide heated on charcoal is reduced with
a  kind of explosion, and soon again vola-
tilized. Heated in a glass retort, it fuses
   Vol.. IF
into a straw-coloured striated mass. It ap-
pears to contain about 16 per cent of oxy-
gen.
  Tellurium is oxidized  and dissolved by
the principal acids.  To  sulphuric acid it
gives a deep purple  colour.  Water sepa-
rates it in black flocculi, and heat throws
it down in a white precipitate.
  With nitric acid it forms a colourless so-
lution, which remains so when diluted, and
aflbrds slender dendritic crystals by  eva-
poration.
  The muriatic acid, with  a small portion
of nitric, forms a transparent solution, from
which water throws down  a white submu-
riate.  This may be  redissolved almost
wholly by repeated affusions of water. Al-
cohol likewise  precipitates it.
  Sulphuric acid, diluted with two or three
parts of water, to which a  little nitric acid
has  been added, dissolves  a large portion
of the metal, and the  solution  is  not de-
composed by water.
  The alkalis throw down from its solutions
a white precipitate, which  is soluble in all
the  acids, and by an excess of the alkalis
or their carbonates.  They are not preci-
pitated by prussiate of potash.  Tincture
of galls gives a yellow flocculent precipi-
tate with them.  Tellurium is precipitated
from them in a metallic state by zinc, iron,
tin, and antimony.
  Tellurium fused with an equal weight of
sulphur, in  a gentle heat, forms a lead-co-
loured  striated sulphuret.  Alkaline  sul-
phurets precipitate it from its solutions  of
a brown or black colour.  In this precipi-
tate either the  metal or its oxide is  com-
bined with sulphur.  Each of these sulphu-
rets burns with a pale blue flame, and white
smoke.  Heated in a retort, part of the sul-
phur is sublimed, carrying up  a little  of
the metal with it.  It does not easily amal-
gamate with quicksilver.
  * Teli.ure tted Hydrogen. Telluri-
um  and hydrogen combine to form a  gas,
called  telluretted hydrogen.  To make  this
compound,  hydrate  of potash, and oxide
of tellurium are ignited with charcoal, and
the mixture acted on by dilute sulphuric
acid, in a retort connected  with a mercu-
rial pneumatic apparatus.  An elastic fluid
is generated, consisting of hydrogen hold-
ing tellurium in solution.   It is possessed
of very singular properties. It is soluble
in water, and forms a claret-coloured solu-
tion.  It combines  with the  alkalis.   It
burns with a bluish flame,  depositing ox-
ide  of  tellurium. Its smell is very strong
and peculiar, not unlike that of sulphuret-
ted hydrogen.   This elastic fluid  was dis-
covered by Sir  II. Davy in 1809.  When
tellurium is  made the electrical negative
surface in water in  the voltaic circuit, a
brown  powder  is formed,  which appears
                      19 
TEM                                 TER
to be a solid combination of hydrogen and
tellurium.  It was first  observed by  Mr.
Ritter  in  1808:   The composition of the
gas and the solid hydruret has  not  been
ascertained.  The prime equivalent of tel-
lurium according to Sir  H. Davy, is  4.93,
reduced to the oxygen  radix.   Berzelius
makes the oxide of tellurium a compound
of metal 100 + oxygen 24.8.  If we call the
oxygen 25, then the atom or prime would
be 4.  In this case, telluretted hydrogen,
if analogous  in its constitution to sulphu-
retted hydrogen, would  have  a sp. gr. of
2.2916, (not  2.3074,  as  Dr. Thomson de-
duces it from the very same data).*
  •Temperature.  A definite term of
sensible heat, as measured by the thermo-
meter.  Thus we say a  high temperature,
and  a low temperature,  to denote a mani-
fest  intensity of heat  or cold; the tempe-
rature of boiling water,  or 212" Fahr.; and
a range of temperature, to designate the
intermediate  points of heat  between  two
distant terms of  thermometric indication.
Accordingto M. Biot, temperatures are the
different energies of caloric,  in  different
circumstances.
  The  general doctrines  of caloric have
been already fully treated of under the ar-
ticles Caloric, Combustion,  Congelation, Cli-
mate, and Pyrometer.
  The changes induced  on matter, at dif-
ferent temperatures,  relate either to its
magnitude, form, or composition. The first
two of these effects are considered under
Expansion, Concreting  Temperatures, and
Pyrometer; the third under Combustion, and
the  Individual Chemical  Bodies. I shall here
introduce  some facts concerning the tem-
perature of  living bodies, and that of our
northern climates, as modified by the con-
stitution of water.
  The power which man possesses of resist-
ing  the impression of external cold is well
known, and  fully exemplified in high lati-
tudes.  That of sustaining high heats has
been made the subject of experiment.  On
the  continent, the girls who are sent into
evens often  endure for a short period a
 heat of 300° F. and upwards.  If the skin
 be  covered  with varnish, which obstructs
 the perspiration, such heats, however, be-
 come intolerable. Dr.  Fordyce staid for a
 considerable time, and  without great incon-
 venience,  in a  room heated by stoves to
 260° of Fahrenheit's scale. The lock of the
 door, his  watch and keys, lying on the ta-
 ble, could not be touched without burning
 his hand.  An egg became hard; and though
 his pulse  beat 139 times  per minute, yet a
 thermometer held  in  his mouth was only
  2° or 3° hotter  than ordinary.  He perspi-
  red most profusely.—Phil.  Trans,  vol. 64
  and 65.
    It  has  been  shown  under  Caloric, that
  fresh water possesses  a  maximum density
about 39J° F.  When its temperature devi-
ates from  this point,  either upwards or
downwards, its density diminishes, or its
volume enlarges,   Hence,  when  the in-
tensely cold air from  the circumpolar re-
gions, presses southwards, after  the au-
tumnal equinox, it progressively abstracts
the heat  from the great natural basins of
water or lakes, till the temperature of the
whole aqueous mass  sinks to  39i*\  At
this term, the  refrigerating influ ence of the
atmosphere, incumbent on the  water, be-
comes nearly  null.  For, as the  superficial
stratum, by farther cooling, becomes spe-
cifically lighter, it remains on the  surfaee,
and soon becomes a cake of ice, which be-
ing an imperfect conductor of heat, screens
the subjacent liquid water from the cold
air.   Had water resembled mercury, oils,
and other liquids, in continuing to  contract
in volume, by cooling, till  its congelation
commenced, then the incumbent  cold air
would have robbed the mass of water in a
lake, of its caloric of fluidity, by unceasing
precipitation  of the cold particles to the
bottom, till the whole sunk to 32°.  Then
the  water at the bottom, as  well as that
above, would have begun to solidify, and
in the course  of a severe winter  in these
latitudes, a deep lake would have become
throughout a  body of ice, never  again to be
liquefied. We can easily see, that such fro-
zen masses would have acted as centres of
baleful refrigeration  to  the  surrounding
country; and  that under such a  disposition
of things, Great Britain must  have  been
another Lapland.  Nothing illustrates more
strikingly the beneficent economy of Pro-
vidence, than  this peculiarity in  the consti-
tution of water, or anomaly, as it has been
 rather preposterously termed. What seems
 void of law to short-sighted man,  is often,
 as in the present case, the finest symmetry
 and truest order.*
   •Tenacity.  See Cohesion.*
   • Tennantite.   Colour,  from  lead-
 gray to  iron-black.   Massive,  but usually
 crystallized, in rhomboidal dodecahedrons,
 cubes, or octahedrons.  Splendent, and tin-
 white; occasionally dull.  Cleavage dode-
 cahedral.   Streak  reddish-gray.   Rather
 harder than gray copper.  Brittle. Sp. gr.
 4.375.  It yields a blue flame  followed by
 arsenical vapours; and leaves a magnetical
 scoria.  Its constituents are copper  45.32,
 sulphur 28.74, arsenic 11.84, iron  9.26, sili-
 ca 5.—Richard Phillips.  It occurs in Corn-
 wall in  copper veins  that intersect granite
 and clay-slate, associated with common cop-
 per pyrites.  It is a variety of gray copper.*
    * Terra   Ponderosa   See   Heavy
  Spar and Barytes.*
    Terra Japonica.  Catechu.
    Terra Lemnia..   A  red  bolar  earth
  formerly esteemed in medicine.  See Lem-
  nian Earth. 
THE                                THE
  Terra Sienna. A brown bole or ochre,
with an orange cast, brought  from Sienna
in Italy, and used in painting, both raw and
burnt. When burnt it becomes of a darker
brown. It resists the fire a long time with-
out fusing.  It  adheres to the  tongue very
forcibly.
  Terre Verte.   This is used as a pig-
ment, and contains iron  in some unknown
state, mixed with clay,  and sometimes with
chalk and pyrites.
  * Thallite.  Epidote or Pistacite.*
  • Thermometer.  An instrument  for
measuring heat, founded on the principle,
that the expansions of matter  are  propor-
tional to the augmentations of temperature.
With regard to aeriform bodies, this prin-
ciple is probably well founded; and hence,
our common thermometers may  be  ren-
dered just, by reducing their indications to
those of  an  air thermometer.  Solids, and
6till more liquids, expand  unequally, by
equal increments of heat, or intervals of
temperature.  With regard to water, alco-
hol, and  oils, this inequality  is so consi-
derable as to occasion  their rejection, for
purposes  of exact thermometry.   But we
nave shown that mercury approaches more
to metals than ordinary liquids, in  its rate
of expansion, and hence, as well as from its
remaining liquid through a long range of
temperature, it is justly preferred to  the
above substances  for  thermometric  pur-
poses. A common thermometer, therefore,
is merely a vessel in  which  very minute
expansions of mercury may be rendered
perceptible; and, by certain rules  of gra-
duation,   be compared  with   expansions
made on the same liquid by other observers.
The first condition  is fulfilled  by connect-
ing a narrow glass tube with a bulb of con-
siderable  capacity, filled with quicksilver.
As this fluid metal expands l-63d by being
heated in glass vessels,  from  the  melting
point of ice  to the boiling point of water, if
10 inches of the tube have a capacity equal
to l-63d  of  that of the bulb, it is  evident
that, should the liquid stand at the begin-
ning of the tube, at 32°, it will rise up and
occupy ten inches of it at 212°.  Hence, if
the tube  be uniform  in its calibre,  and the
above space be  divided into equal parts by
an attached scale, then we shall have a cen-
tigrade or Fahrenheit's thermometer, ac-
cording as the divisions are 100 or 180 in
number.   Such are the general principles
of  thermometric   construction.   But to
make an exact instrument, more minute in-
vestigation is required.
  The tubes drawn at  glass-houses  for
making thermometers, are all more or less
irregular in the bore, and for the most part
conical.  Hence, if  equal apparent expan-
sions of the included mercury  be taken to
represent equal thermometric  intervals,
these equal expansions will occupy  une-
qual spaces in an irregular tube.  The at-
tached scale  should  therefore correspond
exactly to these tubular inequalities; or if
the scale be uniform  in its divisions, we
must be certain that the tube is absolutely
uniform in its calibre.  I may join the au-
thority of Mr. Troughton's opinion  to my
own for  affirming, that a tube of a truly
equable bore is seldom or never to be met
with.  Hence we should never construct our
thermometers on that supposition.
  The first step in the formation of this
instrument, therefore, is  to  graduate the
tube into spaces of equal capacity. A small
caoutchouc bag with a stop-cock and nozzle
capable of admitting the end of the  glass
tube, when it is wrapped round with a few
folds of tissue paper, must be provided, as
also pure mercury and a sensible balance.
Having expelled a little air from the bag,
we  dip the end of the attached glass tube
into the mercury, and by the elastic expan-
sion of the caoutchouc; we cause a small
portion of the liquid to rise into the  bore.
We then  shut the  stop-cock, place the
tube in a horizontal direction, and remove
it from the bag.  The column of mercury
should not exceed half an inch in length.
By  gently inclining the tube, and tapping
it with our finger, we bring the mercury
to about a couple of inches from the end
where we mean to make the bulb, and, with
a file or diamond, mark there the initial line
of the scale.   The slip of ivory, brass, or
paper, destined to receive the graduations,
being laid on a table, we apply the tube to
it,  so that the bottom of the column of
mercury coincides with its  lower  edge.
With a fine point we then mark on the
scale the other extremity of the mercurial
column.   Inclining the tube gently,  and
tapping it we cause the liquid to flow along
till its lower end is placed where the up-
per previously stood.   We apply the tube
to the scale, taking care to make its initial
line correspond to the edge as  before.  A
new point for measuring  equal  capacity
is now obtained.  We thus proceed till the
requisite length be graduated; and we then
weigh the mercury with minute precision.
  The bulb is next formed at the enamel-
ler's blow-pipe in the usual way. One of a
cylindrical or conical  shape,  is preferable
to a sphere, both for  strengh and sensibili-
ty.  We now ascertain, and note down its
weight.  A tubular coil of paper is to be
tied to the mouth of the tube, rising in  a
funnel form an inch or two above it.  Into
this we pour recently boiled mercury, and
applying the gentle heat of a lamp  to the
bulb, we expel a portion ofthe air.  On al-
lowing the bulb to cool, a portion of the
mercury will descend into it, corresponding
to the quantity of  air previously expelled.
The bulb is  now to  be heated over the
lamp till the included mercury boil briskly 
the
tj 1i<:
for some time.  On removing it the quick-
silver will descend from the paper funnel,
and  completely fill  the  bulb and stem.
Should any vesicle of air appear, the pro-
cess of heating or boiling must be repeated,
with the precaution  of keeping  a column
of superincumbent  mercury in  the paper
funnel.  When the temperature of the bulh
has sunk to nearly that of boiling water, it
may be immersed in melting ice.   The fun-
nel and its mercury are then to be removed,
and the bulb is to be plunged into boiling
water.  About l-63d of the included mer-
cury will now be  expelled.  On cooling
the instrument  again  in melting ice,  the
zero point of the centigrade scale, corres-
ponding to 32° of Fahrenheit, will be indi-
cated by the top of the mercurial column.
This point must be  noted with a scratch on
the glass, or else by a mark on the prepared
scale.   We then weigh the whole.
   We have now sufficient data for complet-
ing the graduation of the instrument from
one fixed point; and in hot climates,  and
other situations, where ice, for example,
cannot be conveniently procured, this faci-
lity of forming an exact thermometer is im-
portant, We know the weight of the whole
included mercury, and that of each gradus
 of the stem.  And  as from 32° to 212° F.
 or from 0° to 100° cent, corresponds to a
 mercurial expansion in glass of l-63d, we
 can easily compute  how many of our  gra-
 duating spaces are  contained in the range
 of temperature between freezing and boil-
 ing water.  Thus, supposing the mercurial
 contents to be 378 grains, l-63d of  that
 quantity, or 6 grains, correspond to 180 of
 Fahrenheit's degrees.  Now,  if the initial
 measuring column were 0.6 of a grain,  then
 10 of these spaces would  comprehend the
 range between freezing and boiling water.
 Hence,  if we know the boiling point, we
 can set off the freezing point; or, from the
 temperature of the  living body, 98° F., we
 can set off both the freeing and boiling
 points of water.  In the  present case, we
 must divide each  space on our prepared
 scale into 18 equal parts, which would con-
 stitute degrees of  Fahrenheit; or into 10
 equal parts, which  would constitute centi-
 grade degrees; or into 8, which would  form
 Reaumur's  degrees. I  have  graduated
 thermometers in this way, and have found
 them to be very correct.   When we  have
 ice and boiling water  at our command,
 however, we may dispense with the weigh-
 ing processes.  By plunging the instrument
 into melting ice, and then into boiling wa-
 ter, we find how many of our initial spaces
 on the stem correspond to that interval of
 temperature,  and  we subdivide  them ac-
 cordingly.   If the tube be  very unequable,
 we must accommodate even our subdi-
 visions to its irregularities, for which pur-
 pose the eye is a sufficient guide.
  Thermometers arc used for two different
purposes, each of which requires peculiar
adaptation. Those employed in meteorolo-
gy, or for indicating atmospherical tempe-
rature, are wholly plunged in the fluid, and
hence the stem as  well as bulb are equally
affected  by the calorific energy.  But when
the chemist wishes to ascertain the tempe-
rature of corrosive liquids, or bland liquids
highly heated, he can immerse merely the
bulb, and the naked part of the stem under
the scale.  The portion  of the tube corres-
ponding to the scale, is not  influenced hy
the heat, as in the former case; and hence,
 l-63d part ofthe mercury, which at 32° I'.
 was acted on, has at 212° escaped from its
 influence. (MM. Dulong and Petit  make
 it l-64.8th between 32° and 212°; see Ui-
 lokic).  Hence I  conceive, that a meteo-
 rological  and  a   chemical  thermometer
 ought to be graduated  under the peculiar
 conditions in  which they are afterwards to
 be used. The former should have its stem
 surrounded with the steam of boiling wa-
 ter, while its  bulb  is immersed an inch  or
 two beneath the surface of that liquid, the
 barometer having at the  time an altitude
 of 30 inches.
    For ascertaining the  boiling point  on a
 thermometer stem, I adapt to the mouth
 of a tea-kettle a cylinder of tin-plate, the
 top of which  contains  a perforated  cork.
 Through this, the glass tube can be slid
 to any convenient point; while the  tin cy-
 linder may also be raised or  lowered, till
 the bulb rest  an inch  beneath the water.
 The nozzle of the  kettle is shut  with a
 cork; and at the top of the cylinder, a side-
 hole for escape of the steam is left.  If the
 barometer differs  from 30, by  one  inch,
 then the boiling point of water will differ
 by 1 92° F.   Or 1* F.  by Air.  Wollaston,
 corresponds to a difference of 0.589 of ba-
 rometric pressure.  When the barometer,
 for  example, stands at 29 inches,  water
 boils at 210.08 F.; and when it stands  at
  31  inches,   the   boiling temperature  is
  213.92.  Particular attention must be paid
 to this  source of variation.
    A thermometer for chemical experiments
  should have  its boiling point determined,
  by immersion only of  the bulb and the na-
  ked portion of its stem below the scale, in
  boiling water. It is surely needless to say,
  that the water ought to be pure, since  the
  presence of saline matter affects its boiling
  temperature; and it ought to be contained
  in a metallic vessel.
    Before sealing up the end of the tube,
  we  should draw it into  a capillary  point,
  and heat the  bulb till the mercury occupy
  the whole of the stem.   A touch of the
  blow-pipe flame on the capillary glass will
  instantly close it, and  exclude the air from
  re-entering when the  bulb  becomes cool,
  If this  has been skilfully executed, the co- 
THE                                THE
lumn of mercury will move rapidly from
one end of the tube to the  other, when it
is inverted, with a jerk.  An ivory scale is
the handsomest, but  the most expensive.
Those used in Paris consist of a narrow slip
of paper,  enclosed in a glass tube, which
is  attached in  a parallel direction to the
thermometer stem..   It is  soldered to  it
above, by the lamp,  and hooked to it be-
low, by a ring of glass.  Such instruments
are very convenient  for corrosive  liquids;
and I find them not difficult to construct.
   In  treating of the  measure  of tempera-
ture under Caloric, I have endeavoured
to show, that were the whole  body of the
thermometer, stem and bulb, immersed in
boiling mercury,  it  would indicate 35°
more than it does on the supposition of the
bulb  alone being subjected to the calorific
influence, as takes place in common expe-
riments. But MM. Dulong and Petit state,
that it ought to indicate 680° in the former
case, while Mr. Crichton shows that it ac-
tually indicates 656°  in the latter, giving a
difference of only 24° instead of 35*. This
discordance  between fact  and theory,  is
only apparent;  for we must recollect, that
mercury being an excellent conductor  of
heat, will  communicate  a  portion of that
expansive energy from the immersed bulb,
to the mercury in  the stem, which will be
retained,  in consequence of glass  being a
very imperfect conductor of heat.   Hence
we may infer, that but for this communica-
tion of heat  to the stem, a thermometer,
whose bulb alone is plunged in boiling mer-
cury, would stand at  645* F. or 17° below
the true boiling temperature by an air ther-
mometer, according  to MM. Dulong and
Petit.   If we take the mean  apparent ex-
pansion of mercury in glass, for 180°, be-
tween 32° and 662°, as given by these che-
mists, at l-64th; then the above reduction
would become  34.4° instead of 35°, an in-
considerable  difference.
   In consequence  of  this double compen-
sation, a good  mercurial thermometer,  as
constructed by Crichton, becomes an  al-
most exact measure of temperature, or  of
the relative apparent energies of caloric.
   At the end of the  Dictionary, a table  of
reduction is  given for the three thermo-
metric scales, at present used in Europe;
that of Reaumur, Celsius, or the centi-
grade, and Fahrenheit. The process of re-
duction is  however a very  simple  case of
arithmetic.  To convert the centigrade in-
terval into the Fahrenheit, we multiply by
1.8 or by 6 and 0.3,  marking off the last
figure of the product  as a decimal.  Thus
an  interval of 17° centigrade = 17° X 6
X 0.3 = one of 30.6° Fahrenheit.  But as
the former scale marks the melting of ice
0° and the latter 32°, we must add 32" to
30.6°  to have the Fahrenheit .lumber  =
62.6°.
  Another  form of the same rule of con-
version is,  from double the centigrade in-
terval, subtract one-fifth, the remainder is
the Fahrenheit interval.  Thus from  the
double of 17° = 34°, subtract ^- =  3.4,
the remainder 30.6 is the  corresponding
interval on Fahrenheit's scale.  To convert
the Fahrenheit  intervals into the  centi-
grade, divide by 6 and by 0.3, and mark off

the decimal point; thus: 95°. F. =  ■■■
                                o x 0.3
— 52.77° C.
  When we wish to reduce a Fahrenheit
number  to a  centigrade, we must begin
by deducting the 32° which the former is
in advance, over the latter, at the melt-
ing of ice, or zero of the French scale.
Thus  to convert 95° Fahrenheit to the  cen-

tigrade scale; 95°—32°== 63°;  ^ n .?
  °                               b X 0.3
= 35° C.
  All versed  in arithmetical reduction,
know  how advantageous it  is to confine it
if possible  to  one  rule, and not to blend
two or more.  Hence  the ordinary rule of
multiplying by 9,  and dividing by 5, to
bring  the Fahrenheit to the centigrade in-
tervals, seems less convenient than the  pre-
ceding. With regard to the  Reaumur scale,
however, which is now of rare occurrence,
we may employ the usual proportion of 9
to 4, or to the double add one-fourth.
           F.  = 9-4ths R.  and
           R. = 4-9ths F.
These are the relations of the intervals.
  We must, however, attend to the initial
32° of Fahrenheit.

      c° =
           6x0.3
      F°= (C°x 6x0.3)4-32°
      RO_4(F°-32°)
      r<>— iL
      L ~0T8
      R° = 0.8 X C°.
  In the 15th  volume of the Phil. Maga-
zine, Mr. Crichton of Glasgow has describ-
ed a self-registering thermometer of his in-
vention, consisting of two oblong slips of
steel  and zinc, firmly fixed together by
their  faces; so that the greater expansion
or contraction  of the zinc, over those of
the steel, by the same variations of tempe-
rature, causes  a flexure of the  compound
bar.   As this is secured to a board at «i»«
end, the whole flexure is exercised at the
other, on the short arm  of a  lever index,
the free extremity of which moves along a
graduated arc.   The instrument is origi-
nally adjusted  on a good  mercurial  ther-
mometer; and  the  movements of the arm
are registered  by two fine wires, which are 
THO
THO
pushed before it, and left at the maximum
deviation to the right or left of the last ob-
served position or temperature.  The prin-
ciple is obviously that of Arnold's compen-
sation balance for chronometers.
  An exquisite instrument on  the  same
principle has been invented by M. Breguet,
member  of the academy of sciences,  and
board of longitude of France.  It consists
of a narrow metallic slip, about to~o" °f an
inch thick, composed of silver and platina,
soldered together; and it is coiled in a cy-
lindrical  form.  The top of this spiral tube
is suspended by a brass arm, and the bot-
tom carries, in a horizontal position,  a very
delicate  golden needle, which traverses as
an index, on a graduated circular plate. A
steel stud, rises in the centre of the tube,
to prevent its oscillations from the central
position.   If the silver be on the outside of
the spiral, then the influence of increased
temperature  will increase the curvature,
and move the appended needle in  the di-
rection ofthe coil; while the action of cold
will relax the coil, and move the needle in
the opposite direction. M. Breguet was so
good as present me with two instruments;
both of which are perfect thermometers,
but one is the most sensible which I ever
saw.  For some details concerning it, see
Caloric.   Dr.  Wollaston showed me in
1809 a slip of copper coated with platinum,
which  exhibited by  its curvature,   over
flame, or the vapour of water, the expan-
ding influence of heat, in a striking man-
ner.  For other facts  concerning the mea-
surement of heat, see Caloric*
  •Thorina.   An  earth discovered in
1816 by  M. Berzelius.   He  found it in
small quantities in the gadolinite of Korar-
vet, and  two new minerals which  he calls
the deutofluate of cerium and the double
fluate of cerium and yttria.  It  resembles
zirconia.
  To obtain  it from  those minerals that
contain protoxide of cerium and yttria, we
must first  separate  the oxide of iron by
succinate of  ammonia.   The  new  earth,
indeed, may, when alone, be  precipitated
by  the succinates; but in the analytical ex-
periments in which he has obtained it,  it
precipitated in so  small a quantity  along
with iron,  that  he could not  separate  it
from that oxide. The deutoxide of cerium
is  then  precipitated by ti>e sulphate of
potash; after which the yttria  and the new
earth are precipitated together by caustic
ammonia.  Dissolve them in muriatic acid.
Kvnporate  the  solution to dryness,  and
pour boiling water on the  residue,  which
will dissolve the greatest ;>*-t of the  yttria;
but the undissolved  residue  still  detains
a portion of it.  Dissolve it in muriatic or
nitric acid, and evaporate it till it becomes
as exactly  neutral as possible.  Then pour
water upon it, and boil  it for an instant.
 The new earth is precipitated, and the li-
quid contains disengaged acid.   By  satu-
rating this liquid, and  boiling it a second
time, we  obtain  a new  precipitate of the
new earth.
  This earth, when separated by the filter,
has the appearance of a  gelatinous, semi-
transparent mass.    When washed and '
dried, it becomes white, absorbs carbonic
acid, and  dissolves with  effervescence  in
acids.    Though calcined,  it retains its
white colour; and when the heat to which
it has been exposed was only moderate, it
dissolves readily in muriatic acid; but if
the heat has been violent, it will  not dis-
solve till it be digested in strong muriatic
acid. This solution has a yellowish colour;
but  it becomes  colourless  when diluted
with water, as is the case  with  glucina,
yttria, and alumina.   If it be mixed  with
yttria, it dissolves more readily after hav-
ing been exposed to heat   The neutral
solutions of this earth have a purely astrin-
gent taste, which is neither sweet, nor sa-
line, nor bitter, nor metallic.  In this pro-
perty it differs from   all  other species of
earths, except zirconia.
  When  dissolved in sulphuric acid with
a slight excess of acid,  and subjected to
evaporation, it yields  transparent crystals,
which are not altered by exposure  to the
air, and which have a strong styptic taste.
  This earth dissolves very  easily in nitric
acid; but,  after being heated to redness, it
does not dissolve in it except by long boil-
ing.  The  solution does not crystallize, but
forms a mucilaginous  mass, which becomes
more liquid by exposure  to the air, and
which, when  evaporated by  a moderate
heat, leaves a white, opaque mass, similar
to enamel, in a great measure insoluble in
water.
  It dissolves in muriatic acid, in the same
manner as  in  nitric  acid.   The  solution
does not crystallize.  When evaporated by
a moderate heat, it is converted into a si-
rupy mass, which does not  deliquesce  in
the air, but dries, becomes  white like ena-
mel, and afterwards dissolves only in very
small quantity in water, leaving  a subsalt
undissolved; so that by spontaneous evapo-
ration it lets the portion of muriatic acid
escape to which  it owed its solubility.
  This earth combines  with avidity with
carbonic acid.  The precipitates produced
by caustic ammonia,  or by boiling the neu-
tral solutions of the earth in acids, absorb
carbonic acid from the air in drying. The
 alkaline  carbonates   precipitate  the earth
combined with the whole of their carbonic
 acid.
   The ferruginous   prussiate of  potash,
 poured into a solution of this earth, throws
 down  a  white precipitate, which is com-
pletely re-dissolved by muriatic acid.
  Caustic potash &nd ammonia have no ac> 
TIN                                    TIN
tion  on this earth newly precipitated, not
even at a boiling temperature.
  The solution of carbonate of potash, or
carbonate of ammonia, dissolves  a small
quantity of it,  which precipitates  again
when the liquid is supersaturated with an
acid, and then neutralized by caustic am-
monia; but this earth is much less soluble
in the alkaline carbonates than any of the
earths formerly  known  that dissolve in
them.
  Thorina differs from the other earths by
the following properties: From alumina by
its insolubility in hydrate of potash;  from
glucina, by the same property; from yttria,
by its purely astringent taste, without any
sweetness,  and by the property which its
solutions possess of being precipitated by
boiling when they do not contain too great
an excess  of acid.   It differs from zirco-
nia by  the  following properties:  1. After
being  heated to redness,  it  is still capa-
ble of being dissolved in acids.  2.  Sul-
phate  of potash does  not precipitate  it
from its solutions while it precipitates zir-
conia from solutions containing even a con-
siderable excess of acid.  3. It  is precipi-
tated by oxalate of ammonia,  which is not
the  case with zirconia.   4.  Sulphate of
thorina crystallizes readily, while  sulphate
of zirconia, supposing it free  from alkali,
forms, when dried, a gelatinous,  transpa-
rent mass, without any  trace of crystalli-
zation.*
  * Thorinum.  The  supposed  metallic
basis of the preceding earth,  not  hitherto
extracted.*
  • Thulite.  A hard peach-blossom co-
loured mineral found at Sonland, in Telle-
mark in Norway.*
  * Thumerstone.   Axinite.*
  * Tile Ore.   A sub-species of octohe-
dral red copper ore.*
  Tin is a metal of a yellowish-white co-
lour, considerably harder than lead, scarce-
ly at all sonorous, very malleable, though
not very tenacious.  Under the hammer it
is extended into leaves,  called  tin-foil,
which  are  about  one-thousandth of  an
inch thick, and might easily be beaten to
less  than half that thickness, if the pur-
poses of trade  required  it.  The process
for making tin-foil consists simply in  ham-
mering out a number of  plates of this me-
tal, laid together upon a smooth block or
plate of iron.  The smallest sheets are the
thinnest.  Its specific gravity is 7-29.  It
melts  at about the 442° of  Fahrenheit's
thermometer, and by a continuance of the
heat it  is slowly converted  into  a  white
powder  by oxidation.   Like lead,  it is
brittle when heated  almost to fusion,  and
exhibits a grained or fibrous texture,  if
broken by the blow of a hammer; it may
also be granulated by agitation at the time
of its transition from the fluid to the  solid
state.   The oxide of  tin  resists  fusion
more strongly than that of any other me-
tal; from which  property  it is useful,  to
form an opaque  white enamel  when mixed
with pure glass in fusion.  The brightness
of its surface, when scraped, soon goes off
by exposure to the air; but it  is not sub-
ject to rust or  corrosion  by exposure  to
the weather.
  * To obtain pure tin,  the  metal should
be  boiled  in nitric acid, and the  oxide
which  falls down reduced by heat, in con-
tact with charcoal, in a  covered crucible.
  There are two definite  combinations  of
tin and oxygen.   The first or protoxide is
gray; the second or peroxide is white. The
first is formed by heating tin in the air, or
by dissolving tin in muriatic acid, and ad-
ding water of potash to  the solution whilst
recent, and before it has been  exposed  to
air.  The precipitate, after being heated
to whiteness to expel the  water of the hy-
drate is the pure protoxide.  It is conver-
tible  into  the  peroxide  by being  boiled
with dilute nitric acid, dried and ignited.
According to Sir H. Davy,  the  protoxide
contains 13.5 per cent of oxygen. Suppos-
ing it to consist of a prime equivalent  of
each  constituent, that  of  tin would  be
7.333.   From  the  analyses of  Berzelius
and Gay-Lussac, the peroxide  is composed
of 100 metal + 27.2 oxygen; and if we re-
gard it as containing 2  primes of the lat-
ter principle to 1 of metal,  the prime  of
this will be 7.353.  The mean may  be ta-
ken at 7-35.
  There are also two chlorides of tin. When
tin is  burned in chlorine, a very volatile
clear liquor is formed,  a non-conductor of
electricity,  and  which when mixed with a
little  water, becomes  a  solid crystalline
substance, a true muriate of  tin, contain-
ing the peroxide ofthe metal.  This, which
has been  called the liquor of Libavius,
may be also procured, by  heating together
tin-filings and corrosive sublimate,  or  an
amalgam  of tin and corrosive sublimate.
It consists, accordingto the analysis of Dr.
John Davy, of 2  primes of chlorine = 9 -f-
1 of tin = 7.35.  The other compound of
tin and chorine, is a gray semi-transparent
crystalline solid.  It may be procured  by
heating together an amalgam of tin and ca-
lomel.   It dissolves in water,  and forms a
solution  which  rapidly  absorbs  oxygen
from the  air with deposition  of peroxide
of tin.   It consists of
            Chlorine,     4.5
            Tin,         7.35
  There are two sulphurets of tin.  One
may be made by fusing  tin and sulphur to-
gether. It is of a bluish colour, and lamel-
lated texture.  It consists of 7.35 tin -+- 2
sulphur.  The other sulphuret, or the bi-
sulphuret, is made by heating  together the
peroxide of tin  and sulphur.    It is of a 
TIN
TIN
beautiful gold colour, and appears  in  fine
flakes.  It was formerly called aurum muri-
vum.   According to Dr. John Davy, it con-
sists of 1 prime tin      = 7.35
        2       sulphur  =  4.00
For another mode of'making it, see Aurum
Musivum.
  The salts of tin are characterized by the
following general properties:
  1. Ferroprussiate of potash gives a white
precipitate.
  2. Hydrosulphuret  of potash, a  brown-
black with the protoxide; and  a golden-
yellow with the peroxide.
  3. Galls do not affect  the  solutions of
these salts.
  4. Corrosive sublimate occasions a black
precipitate  with the  protoxide salts;  a
white with the peroxide.
  5. A plate of lead frequently  throws
down metallic tin  or  its oxide, from  the
saline solutions.
  6. Muriate of gold  gives, with the pro-
toxide solutions, the purple precipitate of
Cassius.
  7. Muriate of  platinum  occasions   an
orange  precipitate  with  the  protoxide
salts.*
  Concentrated sulphuric acid, assisted by
heat, dissolves half its weight of tin, at the
same time that sulphureous gas escapes in
great plenty.   By the addition  of water,
an oxide of tin is precipitated.  Sulphuric
acid, slightly diluted, likewise acts upon
this metal; but if much water  be present,
the solution does not take place.   In  the
sulphuric solution of tin, there is an actual
formation or extrication of sulphur, which
renders the fluid of a brown colour while
it continues heated, but subsides by cool-
ing.  The tin is likewise precipitated in
the form of a white  oxide,  by a continu-
ance ofthe heat, or by long standing with-
out  heat.   This solution  affords  needle-
formed crystals by cooling.
  Nitric acid and tin combine together
very  rapidly, without  the assistance of
heat.  Most of the metal falls down in the
form of a white oxide, extremely difficult
of reduction; and the small portion of tin,
which remains suspended, does not afford
crystals, but falls down,  for the most part,
upon the application of heat to inspissate
the fluid.  The strong action  of the nitric
acid upon tin, produces  a singular pheno-
menon, which is happily accounted for by
the  modern  discoveries in chemistry.   M.
de  Morveau has observed,  that in a solu-
tion of tin  by the nitric acid,  no elastic
fluid is disengaged, but ammonia is form-
ed.  This alkali must have been produced
by  the nitrogen of that  part  of the nitric
acid which was employed in affording oxy-
gen to oxidize the tin.
  The muriatic acid dissolves tin very rea-
dily, at the  same time that it becomes of a
darker colour,  and ceases to emit fumes.
A slight effervescence takes place with the
disengagement of a fetid inflammable gas.
Muriatic acid suspends half its weight of
tin, and does not let it  fall by repose.  It
affords  permanent crystals by evaporation.
If the tin contain arsenic, it remains undis-
solved at the bottom  of the fluid.   Hecent
muriate of tin is a very delicate test of mer-
cury.  M. Chenevix says, if a  single drop
of a saturated solution of neutralized ni-
trate, or muriate of mercury,  be  put into
500 grains of water, a few  drops of a solu-
tion of muriate of tin  will  render it a little
turbid,  and of  a  smoke-gray.  He adds,
that the effect is perceptible, if ten times
as much water be added.
  Aqua regia, consisting of two parts nitric
and one muriatic acid,  combines  with tin
with effervescence, and  the development of
much heat.  In order  to  obtain a perma-
nent solution of  tin in this acid, it is neces-
sary to add the metal by small portions at
a time; so that the one  portion may be en-
tirely dissolved before  the  next  piece is
added.  Aqua regia,  in this manner, dis-
solves half its weight of tin.  The solution
is of a reddish-brown, and  in many instan-
ces assumes the form of a  concrete gelati-
nous  substance.  'The  addition of water
sometimes produces the concrete form in
this solution, which is then of  an  opal co-
lour, on account of the  oxide of tin diffu-
sed through its substance.
  The uncertainty attending these experi-
ments with the solution of tin in aqua re-
gia, seems to depend upon the want  of a
sufficient degree of accuracy in ascertain-
ing the specific gravities of the two acid9
which are mixed,  the quantities  of each,
and of the tin,  together with that of the
water added. It is probable, that the spon-
taneous assumption of the concrete state,
depends upon  water imbibed from the at-
mosphere.  The solution of tin in  aqua re-
gia is used by dyers to heighten the co-
lours of cochineal, gum-lac, and some other
red  tinctures,  from  crimson to a bright
scarlet, in the dyeing of woollens.
   The acetic acid scarcely acts upon  tin.
The  operation  of other acids upon this
metal has been  little inquired into.  Phos-
phate, fluate, and borate of tin have been
formed by  precipitating the muriate with
the respective neutral salts.
   If the crystals of the saline combination
of copper with  the nitric acid be grossly
powdered, moistened, and  rolled up in tin-
foil, the salt deliquesces, nitrous fumes are
emitted, the mass becomes hot,  and sud-
denly takes fire.  In  this experiment, the
 rapid transition of the  nitric acid to  the
tin,  is supposed to  produce or  develope
heat enough to  set fire to the nitric salts;
but by what particular changes of capaci-
ty, has not been shown 
TIN                                  TIT
    If small pieces of phosphorus be thrown
  on tin in fusion, it will take up from 15 to
  20 per cent, and form a silvery white phos-
  phuret of a foliated texture, and soft enough
  to be cut with  a  knife, though but little
  malleable.   This phosphuret may be form-
  ed likewise by fusing tin filings with con-
  crete phosphoric acid.
    Tin unites with bismuth by fusion, and
  becomes harder and more brittle in pro-
  portion to the  quantity of that metal  ad-
  ded.  With nickel it forms a white brilliant
  mass.   It cannot easily be united in the di-
  rect way with  arsenic, on account of the
  volatility of this metal; but by heating it
  with the combination of the arsenical acid
  and potash, the salt is  partly decomposed;
  and the tin  combining with the acid,  be-
  comes  converted  into a brilliant brittle
  compound,  of a  plaited  texture.  It  has
  been said, that dl tin contains arsenic; and
  that the crackling noise  which  is heard
  upon bending pieces of tin, is produced by
  this impurity; but, from the experiment of
  Bayen, this appears not to be the fact. Co-
  balt unites  with tin by  fusion;  and forms a
  grained  mixture of a  colour  slightly in-
  clining to violet.  Zinc unites very well
  with tin, increasing its hardness, and di-
  minishing its ductility, in  proportion  as
 the quantity of zinc is  greater.
   This is one  of the  principal additions
 used in making pewter, which consists for
 the most part of tin. The best pewter does
 not contain above one-twentieth part of ad-
 mixture, which consists of zinc,  copper,
 bismuth, or such other metallic substances,
 as experience has shown to be most con-
 ducive to the improvement of its hardness
 and colour.  The inferior sorts of pewter,
 more especially those used abroad, contain
 much lead,  have a  bluish colour,  and are
 soft.   The tin usually  met with  in com-
 merce in this country,  has no  admixture
 to impair its purity, except  such  as may
 accidentally  elude the workmen  at  the
 mines.  But the tin met with in   foreign
 countries, is so much debased by the deal-
 ers in  that article, especially the  Dutch,
 that pewter and tin are considered abroad
 as the same substance.
   Antimony forms a very brittle hard mix-
 ture with  tin; the specific gravity of which
 is less than would have been deduced by
 computation from the specific gravities and
 quantities of each, separately taken. Tung-
 sten, fused with twice its weight of tin, af-
 fords a brown spongy mass, which is some-
 what ductile.
  The uses of tin are very  numerous, and
 so wdl known, that they scarcely need be
pointed out.   Several of them have been
already mentioned.  'The tinning  of iron
and copper, the silvering of looking-glasses,
and the  fabrication  of  a great  variety of
  Vol. II.
  vessels and utensils for domestic and other
  uses, are among the  advantages  derived
  from this vessel.
    Tincal.  Crude borax, as it is imported
  from the East Indies in yellow greasy crys-
  tals, is called tincal.
    Tinglass.   Bismuth.
    •Tinning.  See Iron."
    Titanites. This name has been given
  to certain ores of titanium, containing that
  metal in the state of oxide.   See  the  fol-
  lowing article.
    Titanium.  About twenty years ago,
  the Rev. Mr. Gregor discovered in a kind of
  ferruginous sand, found in the vale of Me-
  nachan, in Cornwall, what he supposed to
  be the oxide of a new  metal, but was  un-
  able to reduce.
   Klaproth, afterward  analyzing what was
  called the real schorl of Hungary, found it
  to be the pure oxide of a new metal, which
  he named titanium, and the same with  the
  menachanite of Mr. Gregor.  Since that ox-
  ide of titanium has been discovered in  se-
  veral fossils.
   We do not know that titanium has been
  completely reduced, except by Lampadius,
  who effected it by means of charcoal only.
  The oxide he employed was obtained from
  the decomposition  of  gallate of titanium
  by fixed alkali.  The metal was of a dark
  copper colour, with much metallic brilli-
  ancy, brittle, and in small scales consider-
  ably elastic.  It tarnishes  in the air, and is
  easily oxidized by heat.   It then acquires
 a bluish aspect.  It detonates with nitre,
 and is highly infusible.  All the dense acids
 act upon it with  considerable energy. Ac-
 cording to Vauquelin, it  is volatilized by
 intense heat.
   The native red oxide is insoluble in the
 sulphuric, nitric, muriatic, and nitro-muri-
 atic acids: but if it be fused with six parts
 of carbonate of potash, the oxide  is dis-
 solved with effervescence.   The sulphuric
 solution when evaporated becomes gelati-
 nous; the nitric  affords rhomboidal crys-
 tals by spontaneous evaporation, but is ren-
 dered turbid by ebullition; the  muriatic
 becomes gelatinous, or  flocculent, by heat,
 and transparent crystals form  in it  when
 cooled; but if it be boiled, oxygenized mu-
 riatic acid gas is evolved,  and a white ox-
 ide thrown down.  Phosphoric and arsenic
 adds take it from the others, and form with
 it a white precipitate.   These  precipitates
 are soluble in muriatic acid, but in no other.
   The solutions of titanium give white pre-
 cipitates with  the alkalis, or their carbo-
 nates; tincture of galls gives a brownish-
 red, and prussiate of potash, a brownish-
 yellow.   If the prussiate produce a  green
 precipitate, this,  according to  Lowitz,  is
owing to the presence of iron.  Zinc, im-
Dicrsed  in the solutions, changes their co«
                     40 
TOL
TOP
lour from yellow to violet, and ultimately to
an indigo; tin produces in them a pale red
tint, which deepens to a bright purple-red.
Hydrosulphuret of potash throws down a
brownish-red precipitate, but they are not
decomposed by sulphuretted hydrogen.
  By exposing phosphate of titanium, mix-
ed with charcoal and borax, to a violent
heat, in  a double crucible luted, M. Che-
nevix obtained a pale white phosphuret,
with some lustre, brittle, of a granular tex-
ture, and not very fusible.
  The oxides of iron and titanium, exposed
to heat with a little oil and charcoal, pro-
duce an alloy of a gray colour, intermixed
with brilliant metallic particles of a golden
yellow.
  Oxide of titanium  was used to give a
brown or yellow colour in painting on por-
eelain, before its nature  was known; but
it was found  difficult to  obtain from it a
uniform tint, probably from its not  being
in a state of purity.
  •Tobacco.   The  expressed  juice  of
the leaves, according to Vauquelin, contain
the following substances:—
  A considerable quantity of vegetable al-
bumen or gluten; supermalate of lime; ace-
tic acid.
  A notable quantity of nitrate and  muri-
ate of potash.  A red matter soluble in al-
cohol and water, which swells considerably
when heated.
  Muriate of ammonia.
  Nicotin.
  Green fecula composed chiefly of gluten,
green resin, and woody fibre.*
  Tolu (Balsam of).  This substance
is obtained from the toluifera balsamum, a
tree which grows in South America.   The
balsam flows from  incisions made  in  the
bark.  It comes to Europe in small gourd
shells.  It is of a reddish-brown colour and
considerable consistence;  and  when  ex-
posed to the air, it becomes solid and brit-
tle.  Its smell is  fragrant, and continues
so, even after the balsam has become thick
by age.  When distilled with  water, it
yields very little volatile  oil, but impreg-
nates the water strongly with its taste and
smell. A quantity of benzoic acid sublimes
if the distillation be continued.
   Mr. Hatchett found it soluble in the  al-
kalis, like the rest of the balsams.   When
he dissolved it in  the  smallest possible
quantity of lixivium of potash, it complete-
ly lost its own odour, and assumed  a  fra-
grant smell;  somewhat resembling that of
the clove  pink.  " This  smell," Mr. Hat-
chett observes, " is not fugitive, for it is
still retained by a solution, which was pre-
pared in June, and has remained in an open
glass during four months."
   When digested in  sulphuric acid, a con-
siderable quantity of pure benzoic acid
sublimes.  When the solution of it in this
acid is evaporated to dryness, and the re-
siduum treated with  alcohol, a portion of
artificial tannin  is obtained; the residual
charcoal amounts to 0.54 of the  original
balsam.
  Mr. Hatchett found, that it dissolved in
nitric acid, with nearly the same pheno-
mena as the resins;  but  it assumed the
smell of bitter almonds, which led him to
suspect the formation of prussic acid. Dur-
ing the solution in nitric acid, a portion of
benzoic acid sublimes.  By repeated di-
gestions, it is converted into artificial tan-
nin.
  It is totally soluble in alcohol, from which
water separates the whole of it, except the
benzoic acid.
  To m b a c.  A white alloy of copper with
arsenic,  commonly  brittle; though if the
quantity of arsenic be small, it is both duc-
tile and malleable in a certain degree. It
is sometimes called white copper.
  * Topaz. According to Professor Jame-
son, this mineral species contains  three
sub-species, common topaz, schorlite, and
physalite.
  Common  topaz.  Colour wine-yellow. In
granular  concretions,  disseminated and
crystallized.  Its primitive form is an ob-
lique prism  of 124° 22'.  The following
are secondary  forms.  An  oblique  four.
sided prism, acuminated  by four planes;
the same, with the acute lateral edges be-
velled; the same, with a double acumina-
tion, and several other modifications, for
which  consult Jameson's Min. vol. i.  p. 75.
The lateral planes are longitudinally streak-
ed. Splendent and vitreous.  Cleavage per-
fect and perpendicular to the  axis of the
prism. Fracture, small conchoidal. Trans-
parent.  Refracts  double.  Harder  than
quartz, or emerald; but softer than corun-
dum.  Easily frangible. Sp. gr. 3.4 to 3.6.
  Saxon topaz  in a  gentle  heat becomes
white, but a strong heat deprives it of lus-
tre and  transparency.  The Brazilian, on
the contrary, by exposure to  a high tem-
perature,  burns rose-red,  and in a still
higher, violet-blue.  Before the blow-pipe
it is infusible.   The topaz of Brazil, Si-
beria, Mucla in Asia-Minor, and  Saxony,
when heated, exhibit at one extremity, po-
sitive, and at the other,  negative electri-
city.  It also becomes electrical by friction;
and retains its electricity very long.  Its
constituents are,
               Braz. Top. Sax. T. Sax. T.
Alumina,        58.38     57.45     59
Silica,           34.01    34.24     35
Fluoric acid,      7.79      7.75      5

               100.18     99.44     99
             Berzelius.   Klapr.  Klapr.
   Topaz forms an essential constituent of a
particular mountain-rock, which is  an ag-
gregate of topaz, quartz, and schorl, and 
TBA                                TRA
 is  named topaz-rock.  Topaz occurs  in
 drusy cavities in granite.  It has been also
 discovered in nests, in transition clay-slate;
 and it is found in rolled pieces in alluvial
 soil. It occurs in large crystals, and rolled
 masses, in an alluvial soil, in the granite
 and gneiss districts of Mar and Cairngorm,
 in the upper parts of Aberdeenshire; and
 in veins, along with tin-stone, in clay-slate
 at St. Anne's, Cornwall.  On the continent,
 it appears most abundantly in topaz-rock
 at Schneckenstein.—Jameson.*
   * Topaxolite.  A variety of precious
 garnet, found at Mussa in Piedmont.*
   • Tortoise-shell.   It approaches  to
 nail or  coagulated albumen in its composi-
 tion.  500 parts, after incineration, leave
 three of earthy matter, consisting of phos-
 phate of lime, and soda, with a little iron.*
   •Touchstone.  Lydian stone, a vari-
 ety of flinty-slate.*
   •Tourmaline.   Rhomboidal tourma-
 line is divided  into two sub-species,  schorl
 and tourmaline.
   Tourmaline.   Colours green and brown.
 In prismatic concretions, rolled pieces, but
 generally crystallized. Primitive form,  a
 rhomboid  of 133°  26'.  It occurs  in  an
 equiangular three-sided prism, flatly acu-
 minated on  the extremities  with  three
 planes.   The lateral edges are frequently
 bevelled,  and thus a  nine-sided  prism is
 formed: when the edges of the bevelment
 are  truncated, a twelve-sided prism  is
 formed; and when the bevelling planes in-
 crease so much, that the original faces  of
 the prism  disappear,  an  equiangular six-
 sided prism is formed.  Sometimes the
 prism is nearly  awanting, when  a double
 three-sided pyramid is formed.  The late-
 ral planes are generally cylindrical convex,
 and deeply longitudinally streaked.  Crys-
 tals imbedded.  Splendent, vitreous.  Cleav-
 age threefold. Fracture conchoidal. Opaque
 to transparent. Refracts double. When view-
 ed perpendicular to the axis ofthe crystal,
 it is more or less transparent; but in the
 direction ofthe axis, even when the length
 ofthe prism is less than  the thickness,  it
 is opaque.  As hard as quartz.  Easily
frangible.  Sp. gr. 3.0 to  3.2.  By friction
 it yields vitreous electricity;  by heating,
 vitreous at one  end,  and resinous at the
 other.   The brown and hyacinth-red vari-
 eties, have these properties in the greatest
 degree.  The ancients called it lyncurium.
 Before the blow-pipe, it melts into a gray-
 ish-white  vesicular enamel.  Its constitu-
ents are, silica 42, alumina 40, soda 10, ox-
ide of manganese with a  little iron 7, loss
 1.—Vauquelin.  It occurs in gneiss, mica-
 slate, talc-slate, &c. The red occurs in Sir
beria, Ava, and Ceylon.—Jameson.*
  Tragacanth (Gum).  This substance,
 which is vulgarly called  gum-dragon, ex-
udes from a prickly  bush, the astragalus
 tragacantha, Lin. which grows wild in the
 warmer climates, and endures the cold of
 our own, but does not here yield any gum.
 This  commodity is brought chiefly from
 Turkey, in irregular lumps, or long vermi-
 cular pieces bent into a variety of shapes;
 the best  sort is white,  semi-transparent*
 dry, yet somewhat soft to the touch.
   Gum-tragacanth differs from all the other
 known gums, in giving a thick consistence
 to a much larger quantity of water;  and in
 being much more difficultly soluble, or ra-
 ther dissolving only imperfectly.  Put into
 water, it slowly imbibes a great quantity of
 the liquid, swells into a large volume, and
 forms a soft but not fluid mucilage; if more
 water  be  added, a fluid solution may be
 obtained by agitation: but the liquor looks
 turbid and wheyish, and on standing, the
 mucilage subsides, the limpid water on the
 surface retaining little of  the gum.  Nor
 does the admixture of the preceding more
 soluble gums promote its  union with the
 water, or render its dissolution more dura-
 ble: when gnm-tragacanth,  and gum-arabio
 are dissolved together in water, the traga-
 canth seems to separate from the mixture
 more speedily than when dissolved by it-
 self.
   Tragacanth is usually  preferred  to the
 other gums for making  up  troches, and
 other like purposes, and  is supposed like-
 wise to be the most effectual as  a medi-
 cine; but on account of its  imperfect solu-
 bility, is unfit for liquid forms.  It is com-
 monly given in powder with the  addition
 of other materials of similar intention; thus
 to one part of gum-tragacanth, are added
 one of gum-arabic, one of  starch, and six
 of sugar.   See Cerasin.
   * Trap Formations in geology.
  Primitive  trap.  The name trap  is de-
 rived  from  the Swedish word trappa,  a
 stair.   Werner understands by trap, rocks
 principally characterized by the presence
 of hornblende, and black iron clay.  Hence
 all rocks occurring in the  primitive class,
 having hornblende as a characteristic, or
 predominating  ingredient,  belong to the
primitive trap formation. The following ta-
 ble from Professor Jameson exhibits the
 rocks of this formation.
   1. Common hornblende rock.
      a. Granular hornblende rock.
      b. Hornblende slate.
  2. Hornblende mixed with feldspar.
      a. Greenstone.
        it. Common greenstone.
        /3. Porphyritic greenstone.
        y. Greenstone porphyry.
        /. Green porphyry.
      b. Greenstone slate.
  3. Hornblende mixed with mica.
   Transition trap.  It  contains greenstone
 and amygdaloid.
  The newest floetz-trap contains several 
                 TRE

rocks which are peculiar to it, and others
that occur in other floetz formations.  The
peculiar or characteristic rocks are, basalt,
wacke, gray-stone, porphyry-slate, and trap-
tuff. These, and also greenstone, are often
called whinstone by mineralogists.*
  * Trap-tuff. It is composed of masses
of  basalt, amygdaloid, hornblende  rock,
sand-stone, and even pieces of wood (as in
thei sland of Canna) cemented together by
a rather loose  spongy  clayey basis, which
has been  formed from decomposed basalt
or  wacke rock.   The masses vary much
in size, from that of a pea, to several hun-
dred weight.  It occurs in  beds, which are
from a few inches to several fathoms thick.
A considerable portion  of Arthur's-seat,
near Edinburgh, is composed of this rock:
there it rests on inclined strata, which be-
long to the oldest coal formation.  It oc-
curs also in  Mull, and many other places
in Scotland.*
   * Tremolite.  This  sub-species  of
straight-edged augite is divided into three
kinds; the asbestous, common, and glassy.
   1. Asbestous tremolite.    Colour  grayish-
white.  Massive, and in fibrous concretions.
Shining,  pearly.   Fragments  splintery.
Translucent on the  edges. Rather easily
frangible.  Soft.  Rather  sectile.  When
struck gently, or rubbed  in  the  dark, it
emits a pale reddish light; when pounded
and thrown on coals, a greenish light. Be-
fore the  blow-pipe, it melts into a white
opaque mass.   It occurs  most frequently
in  granular  foliated limestone, or in dolo-
mite.  It is  found in the former in Glentilt
and Glenelg; in the latter, in Aberdeenshire
and Icolmkill; and in basalt in the Castle-
rock of Edinburgh.
   2. Common tremolite. Colour white.  Mas-
 sive, in distinct prismatic concretions, and
crystallized in a very oblique four-sided
prism, truncated or bevelled on the lateral
edges; in an extremely oblique four-sided
 prism, perfect or variously modified by be-
 velment or truncation. The lateral planes
 are longitudinally streaked.  Vitreous or
 pearly.   Cleavage double oblique  angular,
 of 124° 50' and 55° 50'.  Fracture uneven
 or conchoidal.  Translucent.   As hard as
 hornblende.  Rather brittle.  Sp.  grav. 2.9
 to 3.2.  It melts  with much difficulty and
 ebullition into an opaque glass.  Its consti-
 tuents are; silica 50, magnesia 25, lime 18,
 carbonic acid  and water  5.—Laugier.   It
 occurs with the preceding.
   3.  Glassy  tremolite.    Colour  grayish,
 greenish, yellowish,  and reddish-white.
 Massive, in distinct concretions,  and fre-
 quently crystallized in long acicular crys-
 tals. Shining,  between vitreous and pearly.
 Translucent. As hard as hornblende.  Very
 brittle.  Sp. gr. 2.863.  It is phosphores-
 cent in a low degree.  Infusible.   Its con-
 stituents are,  silica 35.5,  lime  26.5, mag-
               TUX

nesia 16.5, water and carbonic acid 23—
Laugier.  It occurs with the preceding.—
Jameson*
    * Tuiphane.  See Spodumt. ne.*
    * Tripoli.   Colour  yellowish-gray.
Massive.   Fracture  fine or coarse  earthy.
Opaque.   Soft.   Rather easily frangible.
Meagre.   Does not adhere to the tongue.
Sp. gr. 2.2. Infusible.  Its constituents are,
silica, 81, alumina 1.5, oxide of iron 8, sul-
phuric acid 3.45, water 4 55.—Bucholz.  Of
the rottenslone, silica 4, alumina 86, carbon
 10.—Phillips.   It  occurs in beds in coal-
fields, with secondary limestone, and un-
der basalt.  It is found at Bakewell,  in
Derbyshire, where it is  called rottemtone-.
 It is used for polishing stones, metals, and
 glasses.  The tripoli of Corfu is reckoned
 the most valuable.*
   * Trona.  The name given in Africa to
 the native carbonate of soda, found at Su<
 kena, near Fezzan.*
   Tube  of  Saeety.   A tube  open at
 both ends, inserted  into a receiver, the up-
 per end communicating with the external
 air, and the lower being immersed in wa-
 ter. Its intention is to prevent injury from
 too sudden condensation  or rarefaction
 taking place during an operation.  For, if
 a vacuum be produced within the  vessels,
 the external  air will enter through  the
 tube: and if air be generated, the water
 will yield to the pressure, being forced up
 the tube.  Thus, too, the 'height of  the
 water in  the tube indicates the degree of
 pressure from the confined gas or gases.
 See PL VII. fig. 3. A.  It is now more fre-
 quently used in a curved form, ib. fig. 1.;
 and is commonly called a,Welter's  tube.
   * Tufaceous Limestone, or Cai.c
 Tuff.  See Limestone.*
   Tumite.  See Thummerstone.
   * Tungsten.   See Ores of  Tung-
 sten.*
   Tungstenum.  This name, signifying
 heavy stone, was given by the Swedes to a
 mineral,  which Scheele found to contain a
 peculiar  metal, as he supposed, in the state
 of an  acid, united  with lime.  The same
 metallic substance was afterward found by
 the Don d'Elhuyarts united with iron and
 manganese in wolfram.
   From the first of these the oxide maybe
 obtained by digesting its powder in thrice
 its weight of nitric  acid; washing the yel-
 low powder that remains, and digesting it
 in ammonia, by which a portion of it is dis-
 solved.   'These alternate digestions are to
 he repeated, and the tungstic oxide pre-
 cipitated  from the ammoniacal solutions
 by nitric  acid.  The precipitate is to be
 washed with Water, and exposed to a mo-
 derate heat,  to expel any ammonia that
 may adhere to it.  Or the mixture may be
 evaporated to a dry mass, which is to be
 calcined under a muffle, to dissipate  the 
TUN
TUR
nitrate of ammonia. From wolfram it may
be obtained by the same process, after the
iron and manganese  have been dissolved
by muriatic acid.
 " The Spanish chemists reduced the oxide
of tungsten to the metallic  state, by ex-
posing it moistened with oil, in a  crucible
lined with charcoal, to an intense  heat.
After two hours, a piece of metal weighing
40 grains,  but slightly  agglutinated,  was
found at the bottom of the crucible. Some
have attempted its reduction in vain; but
Guyton, Ruprecht, and Messrs. Aikin and
Allen, have  been more successful.   The
latter gentlemen produced it from the am-
moniuret.  From  240 grains  of this  sub-
stance, in  acicular  crystals,  exposed for
two hours to a powerful wind  furnace,  in
a crucible lined  with charcoal, they obtain-
ed a slightly cohering mass  of  roundish
grains, about the size ofa pin's head, with
a very brilliant metallic lustre, and weigh-
ing in the whole 161 grains.
   Tungsten is said to be of a grayish-white
or iron colour, with considerable brilliancy,
very hard, and brittle.  Its specific gravity
Don d'Elhuyarts found to be 17.6; Messrs.
Aikin and  Allen, above  17,22.
   * There are two oxides of  tungstenum,
the brown, and the yellow or tungstic acid.
   The brown oxide  is formed by  transmit-
ting hydrogen gas over tungstic acid, in an
ignited glass tube.  It has a flea-brown co-
lour, and when heated in the air, it takes
fire and burns like tinder,passinginto tungs-
tic acid; which see.
   The brown oxide  consists of
     Tungstenum, 100
     Oxygen,      16.6—Berzel.
   Hence, if we regard it as  composed of 2
primes oxygen -J- 1 metal, its composition
will be
     Tungstenum, 12.05      100.
     Oxygen,      2.00       16.6
 Hence the acid prime  ought probably to
 be, 12-05 + 3. = 15.05 or 15; and that of
 the metal  12.
   But from Berzelius's experiments, tungs-
 tate of lime seems to consist of
     Tungstic acid,  100.        14.72
     Lime,          24.12       3.55
 The difference indeed is not great.
   Sir II. Davy found that tungstenum burns
with a deep  red light, when heated in chlo-
 rine, and forms  an orange-coloured volatile
 substance, which  affords the yellow oxide
 of tungstenum,  and muriatic acid,  when
 decomposed by water.*
   Scheele  supposed the white powder, ob-
 tained by digesting the ore in an acid, add-
 ing ammonia to the  residuum, and neutral-
 izing it by nitric acid, to be pure acid of
 tungsten.  In fact it has a sour taste, red-
 dens  litmus, forms neutral crystallizable
 salts with  alkalis, and is soluble in 20 parts
 qf boiling water.  It appears however to be
a triple salt, composed of nitric acid, am-
monia, and oxide of tungsten; from which
the oxide may be obtained in a yellow pow-
der by boiling with a pure concentrated
acid.  In this state it contains about 20 per
cent of oxygen; part of which may  be ex-
pelled by a red heat, when it assumes  a
green colour.
  Tungsten is insoluble  in  the  acids; and
its oxide is nearly the same.  It appears to
be capable of uniting with most other me-
tals, but not with sulphur.  Guyton found,
that the oxide gives great permanence to
vegetable  colours.---Scheele's  Essays.---.
Brongniart's Min.----\"ich. Journ.---Phil.
Mag.—Murray's Chemistry.
  Tungsten  of Bastnas,  or  False
Tungsten.  See Cerium.
   * Turpeth Mineral.   Yellow sub-
deutosulphate of mercury.*
  Turnsole.   Heliotropium.   See  Ar-
 chil.
  Turkey Stone.  Cos Turcica.   See
Whetslate.
  Turmeric (terra merita), curcuma longa,
is a root brought to us from  the East  In-
dies.  Berthollet had an opportunity of ex-
 amining some turmeric that came from To-
 bago, which was superior to that which is
 met with in commerce, both in the size of
 the roots and the abundance of the colour-
 ing particles.  This substance is very rich
 in colour, and there is no other which gives
 a yellow colour of such brightness;  but it
 possesses no durability, nor can mordants
 give  it a sufficient degree.  Common salt
 and sal ammoniac, are those which fix the
 colour best, but they render it deeper and
 make it incline to brown: some recommend
 a small quantity of muriatic  acid.   The
 root  must be reduced to powder to  be  fit
 for use.  It is sometimes employed to give
 the yellows made with  weld a gold cast,
 and to give an orange tinge to scarlet;.but
 the shade the turmeric imparts, soon dis-
 appears in the air.
   Mr. Guchliche gives  two processes  for
 fixing the colour of turmeric on silk.   The
 first  consists in aluming  in  the  cold  for
 twelve hours, a pound of silk in a solution
 of two ounces of alum, and dyeing it hot,
 but without boiling, in a bath composed of
 two  ounces of turmeric and a quart  (mea-
 sure) of aceto-citric acid,  mixed with three
 quarts  of water.  The second process con-
 sists in extracting the colouring  particles
 from the turmeric by aceto-citric acid,  in
 the way described for Brazil wood, and in
 dyeing the silk, alumed as already mention-
 ed, in this liquor, either cold or only mode-
 derately  warm.  The colour is rendered
 more durable by this than by  the former
 process.   The first parcel immersed ac-
 quires a gold yellow; the colour of the se-
 cond and third parcels is lighter, but of
 the same kind; that of the fourth is a straw 
ULM
ULM
colour.  Mr. Guchliche employs the same
process to extract fine and durable colours
from fustic, broom, and French berries; he
prepares the wool by a slight aluming, to
which  he adds a little muriatic acid.  He
seems  to content himself in these  cases
with vinegar or some other vegetable acid,
instead of his aceto-citric acid, for the ex-
traction of the colour; he directs that a
very small  quantity of  solution of tin
should be put into the dye-bath.
  Turpentine is a resinous juice ex-
tracted from several trees. Sixteen ounces
of Venice turpentine, being distilled with
water,  yielded   four  ounces  and  three
drachms of essential oil; and the  same
quantity, distilled without water,  yielded
with the heat of  a water-bath, two ounces
only. When turpentine is distilled or boil-
ed with water till it becomes solid, it ap-
peal's yellowish; when the process is far-
ther continued, it acquires a reddish-brown
colour.  On distilling sixteen ounces  in a
retort  with  an  open fire,  increased by de-
grees,  Neumann obtained, first, four ounces
of a limpid colourless oil; then two ounces
and a drachm of a dark brownish-red em-
pyreumatic oil, of the consistence of a bal-
sam, and commonly distinguished  by that
name.
  The essential oil, commonly called spirit
of turpentine, cannot without singular diffi-
culty be dissolved in alcohol,  though ter-
pentine itself is easily soluble in that spirit.
One part of the oil may be dissolved  in se-
ven  parts of alcohol; but on  standing a
while,  the greatest part of the oil  sepa-
rates and falls to the bottom.
  * Turojjois,  Mineral, or Calaite.
Colours smalt-blue and apple-green.  Mas-
sive, disseminated,  and  imitative.   Dull.
Fracture conchoidal or  uneven.  Opaque.
Harder than  feldspar,  but  softer  than
quartz. Streak, white.  Sp. gr. 2.86 to 3.0.
Its constituents are, alumina  73, oxide of
copper 4.5, water 18, oxide of iron 4.—John.
It occurs in  veins in clay-ironstone, and in
small pieces in alluvial clay.   It has been
found only in the neighbourhood of Nicha-
bour, in  the Khorassan,  in  Persia.  It  is
very highly prized as an ornamental  stone
in Persia, and the neighbouring countries.
Malchite yields a green streak, but that of
calaite is white.  Bone turquois is phosphate
of lime, coloured with oxide of copper.*
  Tutenag. This name is given in India
to the metal zinc.  It is sometimes applied
to denote  a  white  metallic  compound,
brought from China, called also  Chinese
copper, the art  of  making which is not
known in Europe.  It is very tough, strong,
malleable, may be easily cast,  hammered,
and polished; and the better kinds of it,
when well manufactured, are very white,
and not more  disposed to tarnish than sil-
ver is.  Three ingredients of thi9 compound
may be discovered  by analysis;  namely,
copper, zinc, and iron.
  Some of the Chinese white copper is said
to be merely copper and arsenic.
  Type Metal.  The basis of type metal
for printers is lead, and the principal arti-
cle used in communicating hardness is an-
timony, to which copper and brass in vari-
ous proportions are added. The properties
of a good  type  metal are, that it should
run  freely into  the mould, and  possess
hardness without being excessively brittle.
The smaller  letters are made of a harder
composition than those of a larger  size.  It
does not appear that our type-founders are
in possession of a good composition for this
purpose.   The  principal  defect of their
composition appears to be, that the metals
do not uniformly unite.  In a piece of cast-
ing performed at one of our principal foun-
deries, the thickness  of  which was two
inches, I found one side hard and brittle
when scraped, and the other side,  consist-
ing of nearly half the piece, was soft like
lead. The transition from soft to hard was
sudden, not gradual.  If a parcel of letter
of the  same size and casting be examined,
some of them are brittle and hard, and re-
sist the knife, but others may be bent and
cut into shavings.  It  may easily  be ima-
gined,  that the duration and neatness  of
these types must considerably vary. I have
been informed, but do not  know the fact
from trial, that the types cast in Scotland
are harder and more uniform in their qua-
lities.
U
    ULM1N.  Dr. Thomson has given this
      temporary name to a very singular
substance lately examined by Klaproth.  It
differs essentially from every other known
body, and must therefore constitute a new
and peculiar vegetable principle.  It exu-
ded spontaneously from the trunks of a spe-
cies of elm, which Klaproth conjectures to
be the ulmus nigra, and was  sent to, him
from Palermo in 1802.
  1. In its external characters it resembles
gum.  It was solid, hard, of a black colour,
and had considerable lustre.  Its powder
was brown.   It dissolved readily in the
mouth, and was insipid.
  2. It dissolved speedily in a small quan-
tity of water.  The solution was transpa-
rent, of a blackish-brown colour, and, even
when very much concentrated by evapora-
tion, was not in the least mucilaginous or 
                 URA

Iropy; nor did it answer as a paste. In this
respect ulmin differs essentially from gum.
  3. It was completely insoluble both in al-
cohol and ether. When alcohol was poured
into the aqueous solution, the greater part
of the ulmin precipitated  in light brown
flakes.  The remainder was obtained by
evaporation, and was not sensibly soluble
in alcohol.  The alcohol by this treatment
acquired a sharpish taste.
  4. When a few drops of nitric acid were
added to the aqueous  solution,  it became
gelatinous, lost its blackish-brown colour,
and a light brown substance precipitated.
The whole solution was slowly evaporated
to  dryness, and the reddish-brown pow-
der, which remained, was  treated with al-
cohol.  The alcohol  assumed a golden-yel-
low colour; and when evaporated, left  a
light-brown, bitter, and sharp resinous sub-
stance.
  5. Oxymuriatic acid produced precisely
the same effects as nitric. Thus  it appears
that ulmin, by the addition of a little oxy-
gen, is converted into a resinous  substance.
In this  new state it  is insoluble in water.
This property  is very singular.   Hitherto
the volatile oils were the only substances
known to assume the form of resins. That
a substance soluble in water should assume
the resinous form with such facility, is very
remarkable.
  6. Ulmin,  when  burnt, emitted little
smoke or flame, and left a  spongy but firm
eharcoal, which, when burnt in the open
air, left only a little carbonate  of  potash
behind.
  Such are the properties of this curious
substance, as far as they have  been  exa-
mined by Klaproth.
  Ultramarine.  See Axure-stone.
  • Umber.   See Ores  of Iron.*
  Uranglimmer.   An ore of uranium,
formerly called green mica, and by Werner
chalcolite.  See the following article.
  Uranite, or Uranium. A new metal-
lic substance, discovered by the celebrated
Klaproth in the mineral called Pechblende.
In this it is in the state of sulphuret.  But
it likewise occurs as an oxide in the green
mica, or  uranglimmer, and  in  the uran-
ochre.
  By treating the ores of  the metal  with
the nitric or nitro-muriatic acid, the oxide
will be dissolved; and may be precipitated
by the addition of a caustic alkali. It is in-
soluble  in water, and of a yellow colour;
but a strong heat renders it of a  brownish-
gray.
  To obtain it pure, the ore should be
treated  with nitric acid,  the  solution  eva-
Eorated  to dryness, and the  residuum
 eated, so as to render any iron it  may
contain  insoluble. This being treated with
distilled water,  ammonia is to be poured
into the solution, and digested with it for
               URE

some time, which will precipitate the ura-
nium and retain the copper.   The precipi-
tate, well washed with ammonia, is to be
dissolved  in nitric acid,  and crystallized.
The green crystals, dried on blotting pa-
per, are to be dissolved  in water,  and re-
crystallized, so as to get rid of the lime.
Lastly, the nitrate, being exposed to a red
heat, will  be converted into the yellow ox-
ide of uranium.
  It is very difficult of  reduction.  Fifty
grains,  after being ignited,  were  formed
into a ball with wax, and  exposed in a well
closed charcoal crucible,  to the most vehe-
ment heat of a porcelain furnace, the inten-
sity of which gave 170* on  Wedgwood's
pyrometer. Thus a metallic button was ob -
tained, weighing 28 grains, of a dark gray
colour, hard, firmly cohering, fine grained,
of very minute pores,  and externally glit-
tering. On filing it, or rubbing it with ano-
ther hard  body, the metallic lustre has an
iron-gray colour; but in less perfect assays
it verges to a brown.  Its specific gravity
was 8.1.  Bucholz, however, obtained it as
high as 9.0
  * There is probably but two oxides of
uranium;  the protoxide, which  is grayish-
black; and the peroxide,  which is yellow.
  When uranium is heated to redness in
an  open vessel, it glows like a live coal,
and passes into the protoxide, which, from
the experiments of Shoiibert, consists of
          Uranium, 100      15.7
          Oxygen,     6.373    LO
  The precipitate thrown down by potash
from the nitrate solution  is called the yel-
low oxide.   It consists of
    Uranium, 100      31.4 = 2 primes
   Oxygen,    9.359  3.0 =  3 •
  The oxide is soluble in dilute sulphuric
acid gently heated, and affords lemon-co-
loured prismatic crystals.  Its  solution in
muriatic add, in which it is but imperfect-
ly soluble, affords yellowish-green rhom-
boidal tablets.  Phosphoric acid dissolves
it, but after some time the phosphate falls
down in a flocculent  form, and of a pale
yellow colour.
  It combines with verifiable substances,
and gives  them a brown  or  green colour.
On  porcelain, with the usual flux, it pro-
duces an orange.
  Uranochre.  An ore  of uranium, con-
taining this metal in  the oxidized state.
See the preceding article.
  * Urates. Compounds of  uric or lithic
acid, with the salifiable bases.  See Acid
(Lithic).*
  * Urea. The best process for preparing
urea is to evaporate urine to the consis-
tence of sirup, taking care to regulate the
heat towards the end  of the evaporation;
to add very gradually to  the  sirup its vo-
lume of nitric acid (24*  Baum£) of 1.20;
to stir the mixture,  and immerse it in a 
URE                                  URI
 bath of iced water, to harden the crystals
 of the acidulous nitrate of urea which pre-
 cipitate;  to wash these crystals with ice-
 cold water, to drain them, and press them
 between folds of blotting paper.  When we
 have thus separated the adhering hetero-
 geneous matters, we redissolve the crystals
 in water, and  add to them a sufficient quan-
 tity of carbonate of potash, to neutralize
 the  nitric acid.  We must then evaporate
 the  new liquor, at a gentle heat,  almost to
 dryness; and treat the residuum with very
 pure alcohol, which dissolves only the urea.
 On concentrating the alcoholic solution, the
 urea crystallizes.
   The preceding is M. Thenard's process,
 which Dr. Prout has improved.  He sepa-
 rates the nitrate of potash by crystalliza-
 tion, makes the liquid urea into a paste
 with animal  charcoal, digests this with
 cold water, filters,  concentrates, then dis-
 solves the new colourless urea in alcohol,
 and lastly crystallizes.   The process pre-
 scribed by Dr. Thomson, in the 5th edition
 of his System, does not answer.
   Urea crystallizes  in four-sided prisms,
 which are transparent and colourless, with
 a  slight pearly lustre.  It has a peculiar,
 but  not urinous odour; it does not affect
 litmus or turmeric papers; it undergoes no
 change from  the  atmosphere, except  a
 slight deliquescence in  very damp  wea-
 ther.  In  a strong  heat it  melts, and is
 partly decomposed and  partly sublimed
 without change.  The sp. gr. of the crys-
 tals  is about  1.35.  It is very soluble in
 water.  Alcohol, at  the temperature of the
 atmosphere, dissolves  about 20 per cent;
 and  when boiling, considerably more than
 its own weight, from which the urea sepa-
 rates, on  cooling, in its crystalline  form.
 The fixed alkalis  and alkaline earths de-
 compose it.  It unites with most of the me-
 tallic oxides;  and forms  crystalline com-
 pounds with the nitric and oxalic acids.*
   If cautiously  introduced into  a  retort
 with  a  wide  short  neck, it fuses with a
 gentle heat: a white fume rises,  which is
 benzoic acid,  and condenses on the sides
 of the receiver: crystallized carbonate of
 ammonia  succeeds,  and continues to the
 end:  neither water  nor oil rises, but the
 sublimate is turned brown: the air expelled
 from the apparatus is impregnated with a
 smell of garlic and  stinking fish: when the
 heat is very intense, the smell is insupport-
 able. The matter in the retort is then dry,
 blackish, and  covered with a raised  white
 crust, which rises at length in a heavy va-
 pour, and attaches itself to the lower part
 ofthe retort.  This  is muriate of ammonia.
   If water be  poured on the residuum, it
emits a smell of prussic acid.   Burned on
 an open fire it exhales the same smell, gives
out ammonia, and leaves one-hundredth of
its weight of acrid white ashes, which turn
sirup of violets green, and contain a small
quantity of carbonate of soda.
  The aqueous solution, distilled by a gen-
tle  fire, and  carried to ebullition,  affords
very clear water loaded with ammonia. By
adding more water, as the liquor became
inspissated, Fourcroy and Vauquelin ob-
tained nearly two-thirds of the weight of
the urea in carbonate of ammonia, and the
residuum  was  not then exhausted of it.
The latter portions, however,  were more
and more coloured.
  This decomposition of an animal  sub-
stance at the low  heat of boiling water is
very remarkable, particularly with respect
to the carbonic acid.   Indeed  it appears
that a very slight change of equilibrium is
sufficient to cause its constituent principles
to pass into the state of ammonia, and car-
bonic, prussic, and acetous acids.
  • Urea has been recently analyzed by Dr.
Prout, and M. Berard.  The following are
its constituents:—
             Per cent. Per cent. Per atom.
  Hydrogen,   10.80    6.66   2 =  2.5
  Carbon,     19.40   19.99   1 =  7.5
  Oxygen,     26.40   26.66   1 = 10.0
  Azote,      43.40   46.66   1 = 17.5
              100.00  100.00        37.5
  See Sugar for some remarks on the re-
lation between it and urea.  Uric, or lithic
acid, is a substance quite distinct from urea
in its composition. This fact, according to
Dr. Prout, explains, why an excess of urea
generally accompanies  the phosphoric dia-
thesis, and not the lithic.  He has several
times seen  urea as abundant in the urine of
a person where  the phosphoric  diathesis
prevailed,  as to crystallize spontaneously
on the addition of nitric acid,  without be-
ing concentrated by evaporation.
  As urea  and uric acid, says  Dr. Berard,
are the most azotized of all animal substan-
ces, the secretion of urine appears to  have
for its object, the separation of the excess
of azote from the blood, as respiration se-
parates  from it the excess of carbon.*
  Urea  has a singular effect on the crystal-
lization  of  some salts.   If muriate of soda
be  dissolved in  a solution of urea, it will
crystallize  by evaporation, not in cubes, but
in  octaedra;  muriate of ammonia, on the
contrary, treated in the same way, instead
of crystallizing in octaedra, will assume the
cubic form.  The same effect is produced,
if fresh  urine be employed.
  Uuic Acid.  See Acid (Lithic).
  Urine.  This excrementitious fluid, in
its  natural  state, is transparent, of a yellow
colour,  a peculiar smell and  saline taste.
Its  production as to quantity,  and in some
measure quality, depends on  the seasons
and the peculiar constitution of the indivi-
dual,  and is likewise modified by disease.
It is observed, that perspiration carries off 
uri                                  uri
more or less of the fluid, which would else
have  passed off by urine; so that the pro-
fusion of the former is attended with a di-
minution of the latter.
   From the alkaline smell of urine kept for
a certain time, and other circumstances, it
was formerly supposed to be an alkaline
fluid; but by its  reddening paper stained
blue with litmus  or the juice of radishes,
it appears to contain an excess of acid.
  The numerous researches made concern-
ing urine have given the following  as its
component parts:  1, water; 2, urea; 3, phos-
phoric acid; 4, 5,  6, 7,  phosphates of lime,
magnesia, soda, and ammonia; 8, 9, 10, 11,
lithic, rosacic, benzoic, and carbonic acids;
12, carbonate of  lime; 13, 14, muriates of
soda  and  ammonia;  15, gelatin; 16,  albu-
men;  17, resin; 18, sulphur.
   Muriate of potash  may sometimes be de-
tected in urine, by cautiously dropping into
it  some tartaric acid;  as may sulphate of
soda, or of lime, by a solution of muriate of
barytes, which  will throw down sulphate of
barytes together  with its phosphate; and
these may be separated by a sufficient quan-
tity of muriatic acid, which will take up the
latter.
   Urine soon undergoes spontaneous chan-
ges, which  are more  or less speedy and
extensive, according to its state, as well as
the temperature of the air. Its smell, when
fresh made, and healthy, is somewhat fra-
grant; but this presently goes off, and is
succeeded by a peculiar odour termed uri-
nous.  As it begins to be decomposed, its
smell is not very  unlike that of sour milk;
but this soon changes to a fetid, alkaline
odour.  It must be observed, however, that
turpentine, asparagus, and many other ve-
getable substances, taken as medicine, or
used  as food, have a very powerful  effect
on the smell of the urine.  Its tendency to
putrefaction depends almost wholly on the
quantity of gelatin and albumen it contains;
in  many cases, where tliese are  abundant,
it comes on very quickly indeed.
  • According to  Berzelius, healthy human
urine is composed of, water 933, urea30.10,
sulphate of potash  3.71, sulphate of soda
3-16,  phosphate of soda 2.94, muriate  of
soda 4.45, phosphate of ammonia 1.65, mu-
riate of ammonia 1.50, free acetic acid, with
lactate of ammonia, animal matter soluble
in alcohol, urea adhering to the preceding,
altogether 17.14, earthy phosphates with a
trace  of fluate of lime 1.0,  uric acid  1,
mucus of the bladder  0.32, silica 0.03,  in
1000.0. The phosphate  of ammonia and
soda, obtained from urine, by removing by
alcohol the urea from its crystallized salts,
was called fusible salt of urine, or microcos-
mic salt, and was  much employed in expe-
riments with the blow-pipe.*
  The changes produced in urine by dis-
   Vol. II.
ease are considerable, and of importance
to be known.  It is of a red colour, small
in quantity, and  peculiarly acrid, in inflam-
matory diseases; but deposites no sediment
on standing.  Corrosive muriate of mercury
throws down from it a copious precipitate.
Toward  the termination of such diseases,
it becomes more abundant, and deposites a
copious pink-coloured sediment, consisting
of rosacic acid,  with a Httle phosphate  of
lime and uric acid.                •
   In jaundice'it contains a deep yellow co-
louring matter,  capable of staining linen.
Muriatic acid renders it green, and this in-
dicates the presence of bile.  Sometimes,
too, according to Fourcroy and Vauquelin,
it contains a substance analogous to the
yellow acid, which  they formed by the ac«
tion of nitric acid on muscular fibre.
   In  hysterical  affections,  it is  copious,
limpid, and  colourless, containing much
salt, but scarcely any  urea or gelatin.
   In dropsy the  urine is generally loaded
with albumen, so as to  become milky,  or
even coagulate by heat, or on the addition
of acids.   In  dropsy  from diseased liver,
however, no  albumen is present; but the
urine is  scanty, high-coloured, and depo-
sites the pink-coloured sediment.
   In  dyspepsy,  or  indigestion, the urine
abounds  in gelatin, and putrefies rapidly.
   In  rickets, the  urine contains a great
deal of a calcareous salt, which has  been
supposed to be phosphate of lime, but ac-
cording to Bonhomme it is the oxalate.
   Some instances are  mentioned, in which
females have voided urine of a milky ap-
pearance, and containing a certain portion
of the caseous part of milk.
   But among the most remarkable altera-
tions of urine is  that in the diabetes, when
the urine is sometimes so loaded with su-
gar, as to be capable of being fermented
into a vinous liquor.   Upwards of l-12th
of its weight of  sugar was extracted from
some diabetic urine by Cruikshank, which
was at the  rate of twenty-nine ounces troy
a-day from one  patient.  In this  disease,
however, the urine, though always in very
large quantity, is sometimes not sweet, but
insipid.
   The urine of some animals, examined by
Fourcroy,  Vauquelin,  and  Rouelle, jun.
appears to differ from  that of man  in want-
ing the phosphoric and lithic acids, and
containing the benzoic. That ofthe horse,
according to the former two, consists of
benzoate of soda .024, carbonate of lime
.011,  carbonate  of  soda .009, muriate of
potash .009, urea .007, water and mucilage
.940.   Giese, however, observes, that the
proportion  of benzoate  of  soda varies
greatly, so that sometimes  scarcely any
can be found.  Notwithstanding the asser-
tions of these chemists,  that the urine of
                     41 
VAR                                 VAR
the horse contains no phosphoric acid, Gio-
bert affirms that phosphorus may be made
from it.
  That of the cow, according to  Rouelle,
contains carbonate, sulphate, and muriate
of potash, benzoic acid,  and urea: that of
the camel differed from  it in affording no
benzoic acid: that of the rabbit, according
to Vauquelin, contains the  carbonates of
lime, magnesia, and potash, sulphates of
potasji and lime, muriate of potash, urea,
gelatin, and sulphur.  All these appear to
contain some free alkali, as they turn sirup
of violets green.  In the urine of domestic
fowls, Fourcroy and Vauquelin found lithic
acid.
   Urine  has been  employed for  making
phosphorus, volatile alkali, and sal ammo-
niac; it adds to the produce of nitre-beds;
and it is very useful in a putrid state for
scouring woollens.
   * Urinary  Calculi.   See Calculi
(Urinary).*
V
* T^APOUR.  The general principles of
    v   the formation of vapour have been
explained  under  the  article  Caloric,
changes of state.  Some observations have
been  added  under  Evaporation  and
Gas.
  Fig. 15. plate XIV. represents one form
ofthe apparatus, which I employed for de-
termining the elastic force  of vapours at
different temperatures. L, 1, are the initial
levels of the mercurial columns in the two
legs ofthe syphon barometer. I, is the fine
wire of platina, to which the quicksilver
was made a tangent, at every measurement,
by pouring mercury into  the open leg,  till
its vertical pressure equipoised the elastic
force  of the vapour above I.   The  column
added over L, measured directly that elas-
tic  force. See the Tables in the  Appen-
dix.*
  * Varec  The French name for kelp,
or incinerated sea-weed.*
  Varnish.   Lac-varnishes or lacquers
Consist of different resins in a state of so-
lution,  of  which  the  most common  are
mastich, sandarach, lac,  benzoin,  copal,
amber,  and asphaltum. The menstrua are
either expressed or essential oils, as also
alcohol. For a lac-varnish of the first kind,
the common painter's varnish is to be uni-
ted by  gently boiling  it  with some more
mastich or colophony, and then  diluted
again with a little more  oil of turpentine.
The latter addition promotes both the glos-
sy appearance and drying of the varnish.
  Of this sort  is  the amber-varnish.   To
make this varnish, half a pound of amber
is kept over a gentle fire in  a covered iron
pot, in the  lid  of which  there is a small
hole, till it is observed to become soft, and
to be melted together into one mass.   As
soon  as this  is perceived,  the  vessel  is
taken from off the fire, and suffered to cool
a little; when  a pound of good painter's
varnish is added to it, and the whole  suf-
fered to boil up again over the fire, keep-
ing it continually  stirring.  After this, it
is again removed from the fire; and when
it is become  somewhat cool, a pound  of
oil of turpentine is to be gradually mixed
with  it.  Should  the varnish, when it  is
cool, happen to  be yet too thick, it may be
attenuated  with more  oil of turpentine.
This varnish has always a dark-brown co-
lour, because the  amber is previously half
burned in this operation; but if it  be re-
quired of a bright colour, amber powder
must be dissolved in transparent painter's
varnish, in Papin's machine,  by a  gentle
fire.
   As  an instance of the second sort of lac-
varnishes with ethereal oils alone, may be
adduced the varnish made with oil of tur-
pentine.  For making this, mastich  alone
is dissolved in oil  of turpentine by a very
gentle digesting heat, in close glass ves-
sels.  This is the varnish used for the mo-
dern transparencies employed as window-
blinds, fire-screens, and for other purposes.
These  are commonly prints,  coloured on
both sides,  and afterwards  coated  with
this varnish  on those parts that are intend-
ed to be transparent.  Sometimes fine thin
calico, or Irish linen, is used for this pur-
pose;  but it requires to  be primed with a
a solution of isinglass, before the colour  is
laid on.
   Copal may be  dissolved in genuine Chio
turpentine, according to Mr. Sheldrake, by
adding it in  powder to the turpentine pre-
yiously melted, and stirring till the  whole
is fused.  Oil of turpentine may then be
added, to dilute  it  sufficiently.  Or the co-
pal in  powder may be  put  into a  long-
necked matrass with twelve parts of oil of
turpentine, and digested several days on a
sand heat, frequently shaking it. This may
be diluted with  one-fourth  or one-fifth of
alcohol.  Metallic  vessels or  instruments,
covered with two  or three coats of this,
and dried in  an  oven each time, may be
washed with boiling water,  or even ex-
posed to a still greater heat, without injury
to the varnish.
   A varnish ofthe consistence of thin tur-
pentine is obtained for aerostatic machines,
by the digestion  of one part of elastic gum,
or caoutchouc, cut into small pieces, in 
VAR                           #     VEG
thirty-two parts of rectified oil of turpen-
tine.  Previously to its being used, how-
ever, it must  be  passed through  a linen
cloth, in order that the undissolved parts
may be left behind.
  The third sort  of lac-varnishes  consists
in the spirit-varnish.  The most solid re-
sins yield the most durable varnishes; but
a varnish must never  be expected to be
harder than the resin naturally is of which
it is made.  Hence, it is the height of ab-
surdity to suppose, that there are  any in-
combustible varnishes, since there is no
such thing as  an incombustible resin. But
the most solid resins  by  themselves pro-
duce brittle  varnishes; therefore,  some-
thing of a softer substance must always be
mixed with them, whereby this brittleness
is diminished. For this purpose gum-elemi,
turpentine,  or balsam  of  copaiva  are em-
ployed in proper proportions.  For the so-
lution of these  bodies the strongest alco-
hol  ought  to be used, which  may very
properly indeed be distilled over alkali,
but must not  have stood upon alkali.  The
utmost simplicity in composition  with re-
spect to the  number of the ingredients
in a formula is the result  of the  greatest
skill in  the art; hence it is no wonder, that
the  greatest  part of the formulas and re-
cipes that we meet with,  are  composed
without any principle at all.
  In conformity to these  rules,  a  fine co-
lourless varnish may be obtained,  by dis-
solving eight ounces of gum-sandarach and
two ounces of Venice  turpentine in thirty-
two ounces of alcohol by a gentle heat.
Five ounces of shell-lac  and one  of tur-
pentine, dissolved in thirty-two ounces of
alcohol by a very gentle heat, give a harder
varnish, but of a reddish  cast.  To these
the solution of copal  is undoubtedly pre-
ferable in many respects.   This is  effected
by triturating an ounce of powder  of gum-
copal, which has been well dried by a gen-
tle heat, with a drachm of camphor, and,
while  these are mixing  together, adding
by  degrees four ounces  of the strongest
alcohol, without any digestion.
  Between  this and the gold-varnish there
is only this difference, that some substances
that communicate a yellow tinge are to be
added to the latter.  The most ancient de-
scription of two sorts of it, one of winch
was prepared with oil, and the other with
alcohol, is to be found in Alexius Pedemon-
tanus De i Secreti, Lucca, of which the first
edition was published in the year 1557. But
it is better  prepared,  and more durable,
when made after the  following prescrip-
tion:---Take  two ounces  of shell-lac, of
arnatto  and turmeric  of  each one ounce,
and thirty  grains of fine  dragon's-blood,
and make  an extract with twenty ounces
of alcohol in  a gentle heat.
  Qil-varnishes  are  commonly mixed im.
mediately with the colours, but lac or lac*
quer-varnishes are  laid on by themselves
upon a burnished coloured ground; when
they are  intended to be  laid upon naked
wood, a ground should be first given them
of strong size, either alone or with some
earthy colour, mixed up with it by leviga-
tion.  The gold lacquer is simply rubbed
over brass, tin, or silver,  to  give  them a
gold colour.
  Before a resin is  dissolved  in a fixed oil,
it is necessary to render the oil  drying.
For this purpose the oil is boiled with me-
tallic oxides, in which  operation the muci-
lage of the oil  combines  with the metal,
while the oil itself  unites with the oxygen
ofthe oxide.  To acceleftite  the drying of
this varnish; it is necessary to add oil of
turpentine.
  The essential varnishes consist of a so-
lution of resin  in oil of turpentine.   The
varnish being applied, the essential oil  flies
off, and leaves the resin.  This is used only
for paintings.
  When  resins are dissolved in  alcohol,
the varnish dries very speedily, and is  sub-
ject to crack; but this  fault is corrected by
adding a small quantity of turpentine to
the mixture, which renders it brighter,
and less  brittle when dry.
  The coloured resins or gums, such as
gamboge, dragon's blood, &c. are  used to
colour varnishes.
  To give lustre to the varnish after it  is
laid on, it is rubbed with pounded  pumice-
stone and water; which being dried with a
cloth, the work is afterward rubbed with
an oiled  rag  and tripoli.  The  surface  is
last of all cleaned With soft  linen cloths,
cleared of all greasiness  with powder of
starch, and rubbed bright with  the palm
of the hand.
  Vegetable Kingdom.  In the mine-
ral kingdom, little  of  chemical  operation
takes place,  wherein the peculiar locality
or disposition of the principles which act
upon each other, appears to have any  con-
siderable effect.  The principles,  for the
most part simple, act upon each other by
virtue  of their respective attractions;  if
hekt be developed, it is for the most  part
speedily  conducted away; if elastic  pro-
ducts be extricated, they in general make
their escape;^-in  a  word, we  seldom  per-
ceive in  the operations in the  mineral king-
dom, any arrangement, which at all resem-
bles the  artificial dispositions of the  che-
mist.
  But  in the animal and  vegetable king-
doms it is far otherwise.  In  the former of
these,  bodies are%-egularly changed by
mechanical division, by digestion,  and the
application of peculiar solvents, in a tem-
perature exceeding that ofthe atmosphere,
and the whole of the effects  are  assisted,
modified, and kept  up  by an apparatus for 
VEG    •                            VEG
admitting the air of the atmosphere. The
subjects ofthe vegetable kingdom possess
undoubtedly  a  structure  less elaborate.
They exhibit much less of those energies,
which are said  to be  spontaneous.  The
form of their vessels is much simpler, and,
as far as we can perceive, their action  is
obedient to the changes of the atmosphere
if quality and moisture, the mechanical ac-
tion of winds, the temperature of the wea-
ther, and the influence of light.  In  these
organized beings, the  chemist  discovers
principles of a more compounded  nature,
than  any which can be obtained from the
mineral kingdom. These do not previously
exist  in the earth,  and must therefore be
results of vegetable life.
   The most obvious difference between ve-
getables  and animals is, that the latter are
in general capable of conveying themselves
from  place to place;  whereas vegetables,
being fixed in the  same place, absorb, by
means of their roots and leaves, such sup-
port as is within their reach. This appears
on the whole to  consist of air and  water.
The greatest part of the  support of ani-
mals are the products already elaborated
in the vegetable kingdom.  The products
of these  two kingdoms in the hands of the
chemist are remarkably different,  though
perhaps  not  exclusively so.  One  of the
most distinctive characters seems to be the
presence of nitrogen or azotic gas, which
may be extricated from animal substances
by the application of nitric  acid, and en-
ters into the composition of the ammonia
afforded by destructive distillation. It was
long  supposed, that ammonia was exclu-
sively the product of the animal kingdom,
but it is now well known, that certain plants
likewise afford it.
   When it is considered, that by far the
greater part of every organized substance
is capable of assuming the elastic form,
 and being volatilized by heat; that the pro-
 ducts are during life brought into combi-
 nation by slow  and long-continued proces-
 ses, and are kept separate from each other
 in the vessels of the plant or animal; that
 these combinations  are liable to be altered
 by the destruction of those vessels, as well
 as by every notable change of temperature
 —it will not appear  surprising, that  the
 chemical analysis of plants  should be  in
 an imperfect state.   See Analysis.
    In the structure of vegetables we observe
 the external covering or bark, the ligneous
 or woody matter, the vessels or tubes, and
 certain  glandular or knotty parts. The com-
 parative anatomy, and immediate  uses of
  these parts, form an  o|pject of interesting
  research, but less  immediately within the
  province of a chemical work.
    The  nutrition  or  support  of plants  ap-
  pears to require water, earth, light,  and
  air. There are various experiments, which
have been instituted to show, that water ii
the only aliment, which  the root draws
from the earth.   Van Helmont planted a
willow, weighing fifty pounds, in a certain
quantity of earth covered with sheet-lead;
he Wjtered it for five years with  distilled
water; and at the end of that time the tree
weighed one hundred and sixty-nine pounds
three ounces, and the earth in which it hail
vegetated was  found to  have suffered a
loss of no more than three ounces.  Boyle
repeated the same experiment upon a plant,
which at  the end  of two years  weighed
fourteen  pounds  more, without the earth
in which it had vegetated having  lost any
perceptible portion of its weight.
  Messrs. Duhamel and Bonnet supported
plants with moss, and fed them with mere
water: they  observed, that the vegetation
was ofthe most vigorous  kind; and the na-
turalist of Geneva observes, that the flow-
ers were more odoriferous, and the fruit of
a higher flavour.  Care was taken to change
the supports before they could suffer any
alteration.   Mr. Tillet has likewise raised
plants; more especially of the  gramineous
kind, in a similar manner, with this differ-
ence only, that his supports were pounded
glass, or quartz in powder.  Hales has ob-
served, that a plant,  which weighed three
pounds, gained three ounces after a heavy-
dew.   Do we not every day observe hya-
cinths and other  bulbous plants, as well as
gramineous  plants,  raised in  saucers  or
bottles containing mere water?  And Bra-
connot has  lately  found  mustard-seed to
germinate, grow, and produce plants, that
came to  maturity,  flowered,  and ripened
their seed, in litharge, flowers of sulphur,
and  very  small uiiglazed  shot.  The last
appeared least favourable to the growth of
the plants, apparently because their  roots
could not penetrate between it so easily.
   All plants do not demand the same quan-
 tity of water;  and nature has varied the
 organs of the several individuals conforma-
 bly to the necessity of their being supplied
 with this food.   Plants which transpire lit-
 tie, such as the mosses and the  lichens,
 have no need of a considerable quantity of
 this  fluid; and accordingly they are  fixed
 upon dry rocks,  and have  scarcely any
 roots; but plants which  require a larger
 quantity, have  roots  which extend to a
 great  distance,  and   absorb   humidity
 throughout their whole surface.
   The leaves  of plants have likewise  the
 property of absorbing water, and of extract-
 ing from the atmosphere the same principle
 which the root draws from the earth.  But
 plants which  live in the water, and as it
  were swim in  the element  which serves
  them for food, have no need of roots; they
  receive the  fluid at all their pores; and we
  accordingly find, that the fucus, the ulva,
  &c.  have no roots whatever. 
AEG
VEG
  The dung, which is mixed with earths,
and decomposed, not only  affords the ali-
mentary principles we have spoken of, but
likewise favours the growth of the plant by
that constant and steady heat,  which its ul-
terior decomposition produces.  Thus it is
that Fabroni affirms his having  observed
the development of leaves and flowers in
that part of a tree only, which was in the
vicinity of a heap of dung.
  From the preceding circumstances it ap-
pears, that the influence of the earth in ve-
getation  is almost  totally  confined to the
conveyance of water, and probably the elas-
tic products from putrefying substances to
the plant.
  Vegetables cannot live without air.  From
the experiments of Priestley,  Ingenhousz,
and Sennebier; it is ascertained, that plants
absorb the azotic  part of the  atmosphere;
and this principle appears to be the cause of
the fertility  which arises from the use of
putrefying matters in the form of manure.
The carbonic acid is likewise  absorbed by
vegetables,  when its quantity  is small.  If
in large quantity, it is fatal to them.
  Chaptal has observed, that carbonic acid
predominates in the fungus, and other sub-
terraneous plants.   But by causing these
vegetables,  together with  the body  upon
which they were fixed, to pass, by imper-
ceptible  gradations, from an  almost abso-
lute darkness, into the light, the acid very
nearly disappeared; the  vegetable  fibres
being proportionally increased, at the same
time that the resin and colouring principles
were developed, which he ascribes to the
oxygen of the same acid.  Sennebier has
observed, that the plants which he watered
with water impregnated with carbonic acid,
transpired  an extraordinary   quantity of
oxygen, which likewise indicates a decom-
position ofthe acid.
   Light is almost absolutely  necessary to
plants.  In the  dark they grow  pale, lan-
guish, and di«.  The tendency of plants
toward the light is remarkably seen in such
vegetation as is effected in a chamber or
place  where the light is admitted on one
side; for the plant never fails to grow in
that direction. Whether the matter of light
be  condensed into the substance of plants,
or  whether it act  merely as a stimulus or
agent, without which the other requisite
chemical processes cannot be effected, is
uncertain.
   It is ascertained, that the  processes in
plants serve, like those in  animals, to pro-
duce a more equable temperature, which is
for the most part  above that of the atmos-
phere. Dr. Hunter, quoted by Chaptal, ob-
served by keeping a thermometer plunged
in a hole made in  a sound  tree, that it con-
stantly indicated a temperature several de-
grees above that of the atmosphere,  when
it was below the fifty-sixth division of Fah-
renheit; whereas the vegetable heat, in hot-
ter weather, was  always several degrees
below that of the atmosphere.  The same
philosopher has likewise ohserved, that the
sap which, out of the tree, would freeze at
32°, did not freeze in  the tree unless the
cold were augmented 15° more.
  The vegetable heat may increase or di-
minish by several causes, of the nature of
disease;  and it may even become percepti-
ble to  the touch in very cold weather, ac-
cording to Buffon.A
  The principles OT which vegetables are
composed, if we pursue their analysis as
far as our means have hitherto allowed, are
chiefly carbon, hydrogen, and oxygen. Ni-
trogen is a constituent principle of several,
but for  the most part in  small quantity.
Potash,  soda, lime, magnesia, silex, alu-
mina,  sulphur,  phosphorus,  iron,  manga-
nese, and muriatic acid, have likewise been
reckoned in the number; but some of these
occur  only occasionally, and chiefly in very
small  quantities;  and are scarcely  more
entitled  to be considered as  belonging to
them than gold, or some other substances,
that have been occasionally procured from
their decomposition.
   The following are the principal products
of  vegetation:—
   1. Sugar. Crystallizes. Soluble in water
and alcohol. Taste sweet. Soluble in nitric
acid, and yields oxalic acid.
   2. Sarcocol.  Does not crystallize.  Soluble
in water  and alcohol.   Taste bitter sweet.
Soluble  in  nitric acid,  and  yields oxalic
acid.
   3. Asparagin.   Crystallizes.  Taste cool-
ing and nauseous.  Soluble  in  hot water.
Insoluble in alcohol. Soluble in nitric acid,
and converted into bitter principle and arti-
ficial tannin.
   4. Gum. Does not crystallize.  Taste in-
sipid.   Soluble in water,  and forms muci-
lage.  Insoluble  in alcohol.   Precipitated
by silicated potash.  Soluble in nitric acid,
and forms mucous and oxalic acids.
   5. Ulmin.  Does not crystallize.   Taste
insipid.   Soluble  in water,  and does not
form mucilage.   Precipitated  by nitric and
oxymuriatic acids in the state of resin.  In-
soluble in alcohol.
   6. Inulin.  A  white powder.  Insoluble
in cold water.  Soluble  in boiling water;
but precipitates unaltered after the  solu-
tion cools.  Insoluble  in alcohol.   Soluble
in nitric acid, and yields oxalic acid.
   7. Starch.   A white powder.  Taste in-
sipid.   Insoluble  in cold water.   Soluble
in hot water; opaque and glutinous.  Pre-
cipitated by an infusion of nutgalls; preci-
pitate redissolved by a heat of 120°.  In-
soluble in alcohol.  Soluble in dilute nitric
acid, and precipitated  by alcohol.   With
nitric  acid yields oxalic  acid  and a  waxy
matter. 
VEG
VEG
   8. Indigo.  A blue powder.  Taste insi-
 pid.  Insoluble  in  water, alcohol,  ether.
 Soluble in sulphuric acid   Soluble  in ni-
 tric acid, and converted into bitter princi-
 ple  and artificial tannin.
   9. Gluten.  Forms a ductile elastic mass
 with water.   Partially  soluble  in water;
 precipitated by  infusion of nutgalls and
 oxygenized muriatic acid.  Soluble in ace-
 tic acid and muriatic acid.  Insoluble  in
 alcohol.  By fermentation becomes  viscid
 and adhesive, and thenAssumes  the pro-
 perties of cheese.   Soluble in nitric acid,
 and yields oxalic acid.
   10. Albumen.  Soluble in cold water. Co-
 agulated  by heat, and becomes  insoluble.
 Insoluble in alcohol.  Precipitated by infu-
 sion of nutgalls.   Soluble  in  nitric acid.
 Soon putrefies.
   11. Fibrin. Tasteless.  Insoluble in water
 and alcohol.  Soluble in diluted alkalis, and
 in nitric acid.  Soon putrefies.
   12. Gelatin.  Insipid.   Soluble in water.
 Does not coagulate when heated.   Precipi-
 tated by infusion of galls.
   13.  Bitter principle.   Colour yellow or
 brown.   Taste bitter. Equally soluble  in
 water and alcohol   Soluble in nitric acid.
 Precipitated by nitrate of silver.
   14. Extractive   Soluble in water and al-
 cohol.  Insoluble in ether.  Precipitated by
 oxygenized muriatic acid, muriate of tin,
 and muriate of alumina; but not by gelatin.
 Dyes fawn colour.
   15. Tannin.  Taste astringent.   Soluble
 in water and in alcohol of 0.810.   Precipi-
 tated by gelatin, muriate of alumina, and
 muriate of tin.
   16. Fixed oils.  No smell.  Insoluble in
 water and alcohol.   Forms soaps with al-
 kalis.  Coagulated by earthy and metallic
 salts.
   17. Wax.   Insoluble in  water.   Soluble
 in alcohol,  ether, and  oils.  Forms soap
 with alkalis.  Fusible.
   18. Volatile oil. Strong smell.  Insoluble
in water.  Soluble in alcohol.  Liquid. Vo-
latile.   Oily.  By nitric acid inflamed, and
 converted into  resinous substances.
   19. Camphor.  Strong  odour.   Crystal-
lizes. Very little soluble in water.  Soluble
in alcohol, oils, acids.  Insoluble in alkalis.
Burns  with  a  clear  flame, and volatilizes
before melting.
  20. Birdlime.  Viscid.   Taste  insipid.
Insoluble  in water.  Partially soluble in
alcohol.   Very soluble in ether.   Solution
green.
  21. Resins.   Solid.  Melt when  heated.
 Insoluble  in water.   Soluble in  alcohol,
ether, and alkalis.  Soluble in acetic acid.
 By nitric acid converted  into artificial tan-
 nin.
  22. Guaiacum  Possesses the characters
of resins;  but dissolves in  nitric acid, and
yields oxalic acid and no tannin.
   23. Balsams.  Possess the characters of
 the resins, but have a strong smell; when
 heated, benzoic acid sublimes. It sublimes
 also when they are dissolved in  sulphuric
 acid.  By nitric acid converted into artifi-
 cial tannin.
   24. Caoutchouc.  Very elastic.  Insoluble
 in  water and alcohol.   When steeped in
 ether reduced to a pulp, which adheres to
 every thing.   Fusible, and remains liquid.
 Very combustible.
   25.  Gum-resins.  Form  milky  solutions
 with water, transparent with alcohol.  So-
 luble in alkalis. With nitric acid converted
 into tannin. Strong smell.  Brittle, opaque,
 infusible.
   26. Cotton.  Composed of fibres.  Taste-
 less.  Very combustible.   Insoluble in wa-
 ter, alcohol, and ether.   Soluble in alkalis.
 Yields oxalic acid to nitric acid.
   27. Suber.   Burns bright, and swells.
 Converted by nitric acid into suberic acid
 and wax.  Partially soluble in  water and
 alcohol.
   28. Wood.   Composed of fibres.   Taste-
 less.  Insoluble in  water and alcohol. So-
 luble in weak alkaline lixivium.   Precipi-
 tated by acids.    Leaves  much  charcoal
 when distilled in a red heat.  Soluble  in
 nitric acid, and yields oxalic acid.
   * To the preceding we may add, emetin,
 fungin, hematin, nicotin, pollenin, the new
 vegetable alkalis, aconita,  atropia, brucia,
cicuta, datura, delphia, hyosciama, mor-
phia,  picrotoxia, strychnia, vcratria; and
the various vegetable  acids, enumerated
 under the general article Acid.*
   Vegetation (Saline).  M. Chaptal
 has given us a good memoir on this sub-
ject, in the Journal de  Physique,  for Oc-
 tober 1788, entitled Observations  on the
 Influence of the  Air and  Light upon the
 Vegetation of Salts.
   In the operations in the large way, of his
 manufactory of medical and chemical pro-
 ducts, he often observed that salts, particu-
 larly  the  metallic, vegetated on  the side
 most exposed to the light, and the frequen-
cy ofthe effect induced him to make some
 direct experiments on the subject.  For
this purpose he  took several  capsules of
 glass, and covered  the half of each, as well
 above as below, with black silk.   At the
 same time, he prepared solutions of almost
 all the earthy, alkaline, or metallic com-
 pound salts in distilled  water, at the tem-
 perature of the atmosphere   These cap-
 sules were placed on tables in a well closed
 chamber, which  had no chimney, and of
 which the doors and windows were care-
 fully stopped  up, in order  that the evapo-
 ration might not be hastened by any agita-
 tion of the air.  Reflected  light, by which
 I understand the light from the clouds, was
 admitted through a small aperture in one
of the window-shutters.  By this manage-. 
VER
VER
ment, as well as the disposition of the cap-
sules, one-half of each of their respective
cavities received light from the  aperture,
and the other was almost perfectly in dark-
ness.  The  solutions were then carefully
poured into the  capsules by means of a
funnel resting on the middle of the bottom,
so that the border of the fluid was neat and
uniform, without any irregularity or drop
of the fluid falling on the bare surface of
the glass.
  Upwards  of two hundred experiments
were made, with variations of the princi-
pal trials, so as to leave no doubt with  re-
gard to the constancy of the results.  The
most remarkable  fact  is, that the vege-
tation took place on those  surfaces only
which were illuminated.  This phenome-
non was so striking in most of the  solu-
tions, that in the space of a few days, and
frequently even within one single day, the
salt was  elevated  several lines above the
liquor upon the enlightened surface, while
there did not appear the smallest crust or
edge on the dark part.  Nothing could be
more interesting, than to observe this ve-
getation, projecting frequently more than
an inch, and marking the line  of distinc-
tion between  the  illuminated  and  dark
parts of the vessel.   The sulphates of iron,
of zinc, and other metals, more especially
presented this appearance.  It  was gene-
rally observed, that the  vegetation  was
strongest toward the most enlightened part.
   This phenomenon may be rendered still
more interesting, by directing the vegeta-
tion at pleasure toward the different parts
of the vessel.  For this purpose, nothing
more is required than to cover the several
parts  in succession.   For the  vegetation
always  takes  place  in the enlightened
parts, and quickly  ceases in that which is
covered.
   When  the  same solution has stood for
several  days,  the insensible evaporation
gradually depresses its surface, and a crust
or edge of salt is left in the obscure part.
But the salt never rises, or at least very
imperfectly, above the liquor,  and cannot
be compared with  the true vegetation.
   When salts are  suffered to vegetate  in
this manner, the spontaneous evaporation
of the fluid affords very few crystals.  All
the saline matter extends itself on the sides
of the vessel.
   Veins. The ores of metals are frequent-
ly found to fill certain clefts in mountains.
These masses, when they run out in length,
are called  veins.   Inconsiderable  veins,
which  diverge from  the  principal,  are
called slips; and such masses of ore as are
 of considerable magnitude,  but no great
length, are called bellies, or stock-works.
   •Vbratria.  A new vegetable alkali,
discovered lately by  MM.  Pelletier  and
Caventou, in the veratrum sabatilla, or ce-
vadilla, the veratrum album, or white hel-
lebore, and the colchicum autumnale or mea-
dow saffron.
  The seeds of cevadilla, after being freed
from an unctuous and acid matter by ether,
were digested in boiling alcohol.  As this
infusion cooled, a little  wax  was deposit-
ed; and the liquid being evaporated to an
extract,  redissolved in  water, and  again
concentrated by evaporation, parted  with
its colouring matter.  Acetate ot lead was
now poured into the solution, and an abun-
dant yellow  precipitate fell, leaving the
fluid nearly colourless.  The excess of lead
was thrown down by sulphuretted  hydro-
gen, and the filterc d liquor being concen-
trated by evaporation,  was  treated  with
magnesia, and again filtered.   The  preci-
pitate, boiled in alcohol, gave a solution,
which, on evaporation,  left a pulverulent
matter, extremely bitter,  and with  deci-
dedly alkaline characters.  It was at first
yellow, but by solution  in alcohol, and pre-
cipitation by water, was obtained in  a fine
white powder.
   The precipitate by the acetate  of lead,
gave,  on examination,  gallic  acid;  and
hence it is concluded, that the new  alkali
existed in the seed as a gallate.
   Veratria was found in the other  plants
above mentioned.  It is  white, pulverulent,
has  no odour, but excites violent sneezing.
It is very acrid,  but not bitter.  It produ-
ced violent vomiting in very small doses,
and, according to some experiments, afew
grains may  cause death.  It is very little
soluble in cold  water.   Boiling water dis-
solves about -foV 6" Part, and becomes acrid
to  the taste.  It is very soluble in alcohol,
and rather less  soluble  in  ether.  It fuses
at 122° F., and then appears  like wax. On
cooling,  it  becomes  an  amber-coloured
translucent mass.   Heated more highly, it
swells, decomposes,  and burns.  Decom-
posed by  oxide of copper, it gave no  trace
of azote.   It acts on test papers like an al-
kali, and forms  salts  uncrystallizable  by
evaporation. The salts appear like a gum.
The supersulphate  only seems to present
crystals.  Strong  solutions  of tliese  salts
are  partially decomposed by  water.  Vera-
tria falls  down, and the solution becomes
acid.  The bisulphate appears to consist of
     Veratria,        93.723   100
     Sulphuric acid,    6.227    6.6441
The muriate is composed of,
     Veratria,       95.8606   100
     Muriatic acid,   4.1394    4.3181
   Iodine  and chlorine produce with   vera-
tria, an iodate,  hydriodate, chloride, and
muriate.
   Verdigris.   A crude  acetate of cop-
per.
   Verditer, is a blue pigment, obtained
by adding chalk or whiting to the solution
of copper in  aquafortis.  Dr. Merret  says, 
VIT
VOL
that it is prepared in the following man-
ner:  A  quantity of whiting is put into  a
tub, and upon this the solution of the cop-
per is poured.  The mixture is to be stir-
red every day for some hours together, till
the liquor loses its colour.   'The liquor is
then to be poured off, and more solution of
copper is to be added.  This is to be re-
peated till the whiting has acquired the
proper colour.  Then it is to be spread on
large pieces of chalk, and dried in the sun.
  It appears  from M. Pelletier's analysis,
that 100 grains of the very best  verditer
contain, of carbonic acid 30, of water 3-j>
of pure fime 7, of oxygen 9§, and of pure
copper 50. The  author remarks, that the
verditers of inferior  quality contain more
chalk and less copper.
  Verjuice.   A kind of harsh austere
vinegar,  made of the expressed juice of
the wild apple or crab.  The French give
this name to unripe grapes, and to the sour
liquor  obtained from  them.
  Vermilion. The red sulphuret of mer-
cury, or  cinnabar.
  Vessels (Chemical).  See Appara-
tus.
  * Vesuvian.   Idocrase of Haiiy;  a sub-
species of pyramidal garnet.  Colours green
and brown.  Massive,  disseminated, and
crystalli zed.   Primitive form, a pyramid of
129° 30' and 74° 12'.   The following se-
condary  forms occur; a rectangular four-
sided prism,  variously acuminated,  bevel-
led or truncated.  The lateral planes of the
prism  are longitudinally streaked. Glisten-
ing  vitreo-resinous.   Cleavage imperfect,
but in the direction of the diagonals. Frac-
ture small grained uneven.   Translucent.
Refracts double.  Scratches feldspar. Brit-
.tle.  Sp. gr. 3.3 to 34.  It becomes elec-
trical by friction.  Before the blow-pipe  it
melts  without addition into a yellowish,
and faintly translucent glass. Its constitu-
ents are, silica 35.5, lime 33, alumina 22.25,
oxide  of iron 7-5, oxide of manganese 0.25,
loss 1.5.—Klaproth. It occurs in considera-
ble abundance, in unaltered ejected rocks,
in the vicinity of Vesuvius.   The rare blue
 variety is found at Souland, in Tellemark,
 in Norway.  At Naples it is cut into ring-
 stones.*
   Vinegar. See Fermentation (Ace-
 tous);  and  also Acid (Acetic), where
 the mode of making it  is given.
   * Vinegar from Wood.   M. Stolze,
 apothecary at Halle, has discovered a me-
 thod  of purifying vinegar from wood, by
 treating it with sulphuric acid, manganese,
 and common salt, and afterwards distilling
 it over.*
   Vinegar  of Satueh.   Solution  of
 acetate of lead.
    Vinegar  (Radical).   Acetic acid.
    Vital Air.  See Oxygen.
  Vitrification.  See Glass; also Si-
LICA.
  • Vitriol, Wtie, green, red, white. See
ores or Copper, Iron, Cobalt, Zinc*
  Vitriolic  Acid.  See  Acid  (Sul-
phuric)
  Volatile Alkali.  See Ammonia.
  Volatility.   The property of bodies
by which they are disposed to assume the
vaporous or clastic state, and quit the ves-
sels in which they are placed.
  Volcanoes.  The combustion of those
enormous masses of bitumen, which are
deposited in the bowels of the  earth, pro-
duces volcanoes.  They owe their origin
more especially to the strata  of pyritous
coal.  The decomposition or action of wa-
ter upon the pyrities  determines  the heat,
and the  production of a great quantity of
hydrogen, which exerts  itself  against the
surrounding obstacles, and at length breaks
them.  This effect appears to be the chief
cause of earthquakes; but when the con-
course of air facilitates the combustion of
the bitumen and the hydrogen, the flame is
seen to issue out of the chimneys or vents
which are made; and this occasions the fire
of volcanoes.
  There are many volcanoes still in an ac-
tive  state  on  our globe,  independent of
those of Italy, which are the most known.
The  Abbe Chappe  has described  three
burning  in Siberia.  Anderson  and Von
Troil have described those of Iceland; Asia
and Africa contain several; and we find the
remains of these fires or volcanic products
in all parts  ofthe globe.
  Naturalists inform us, that all the south-
ern islands  have been volcanized; and they
are seen daily  to  be  formed by the action
of these subterraneous  fires.   The  black
colour of the  stones, their spongy texture,
the other products of fire, and the identity
of these substances with those of the vol-
canoes at present burning, are all in favour
of the opinion that  their  origin  was the
same.
  When the decomposition of  the pyrites
is advanced, and  the vapours  and elastic
fluids can  no longer be contained in the
bowels of the earth,  the ground is shaken,
and exhibits  the  phenomenon of earth-
quakes.  Mephitic vapours are multiplied
ori the surface of the ground, and dreadful
hollow noises are heard.   In Iceland, the
rivers and springs  are swallowed  up;  a
thick smoke, mixed with sparks  and light-
ning, is then  disengaged from the crater;
and naturalists have observed, when the
smoke  of  Vesuvius  takes  the form of  a
pine, the eruption is near at hand.
   To these preludes, which show the inter-
nal agitation to be great, and that obstacles
oppose the issue of  the volcanic matters,
succeeds an eruption of stones and other 
VOL                         .      VOL
 products, which the lava drives before it;
 and lastly, appears a river of lava, which
 flows out, and spreads itself down the side
 of the mountain.  At this period the calm
 is restored in the bowels of the earth, and
 the eruption  continues  without  earth-
 quakes.  The violent efforts of the includ-
 ed matter  sometimes  cause  the sides of
 the mountain to open; and this is the cause
 which has  successively formed the smaller
 mountains that surround volcanoes.  Mon-
 tenuevo, which  is a hundred and  eighty
 feet high, and three thousand in breadth,
 was formed in a night.
   This crisis is sometimes succeeded by
 an eruption of ashes, which darken the air.
 These ashes  are the last result of the al-
 teration of the coals; and the matter which
 is first thrown out is that which the heat
 has half vitrified.  In the  year 1767,  the
 ashes  of  Vesuvius were  carried twenty
 leagues out to sea, and the  streets of  Na-
 ples were covered with them.  The report
 of Dion, concerning the eruption of Vesu-
 vius in the  reign of Titus,  wherein  the
 ashes were carried into Africa, Egypt, and
 Syria, seems  to be fabulous.   M. de Saus-
 sure observes, that  the soil of Rome is of
 this character, and that the famous  cata-
 combs are all made in the volcanic ashes.
  It must be admitted, however, that  the
 force with which all  these products  are
 thrown is astonishing.  In the year 1769,
 a stone, twelve feet high and four in cir-
 cumference, was thrown to the distance of
 a quarter of a mile from  the  crater:  and
 in the year 1771 Sir William Hamilton  ob-
 served stones of an enormous size, which
 employed eleven seconds in falling.  This
 indicates an elevation of near two thousand
 feet.
  The eruption of volcanoes is  frequently
 aqueous: the water, which is confined, and
 favours the decomposition of the pyrites,
 is sometimes strongly thrown out. Sea salt
 is  found among the ejected  matter,  and
 likewise sal ammoniac.  In the year 1630,
 a torrent of boiling water, mixed with lava,
 destroyed Portici  and Torre del Greco.
 Sir W. Hamilton saw boiling water  eject-
 ed.  The springs of boiling water  in Ice-
 land, and all the hot springs which abound
 at the surface of the globe, owe their heat
 only to the decomposition of pyrites,
  Some eruptions are of a muddy sub-
 stance; and these form  the tuffa,  and the
pouzzolano.   The eruption which buried
Herculaneum is of this kind.  Sir W. Ha-
milton  found  an antique head, the impres-
 sion of which was well enough preserved
 to answer the purpose of a mould.  Her-
culaneum at the least depth is seventy feet
under  the surface of  the  ground, and in
many places one hundred and twenty.
  The pouzzolano is of various colours. It
  Vol. II.
 is usually reddish, sometimes gray, white,,
 or green: it frequently consists of pumice-
 stone in powder; but sometimes it is form-
 ed of oxided clay.  One hundred parts of
 red pouzzolano afforded Bergmann, silex
 55, alumina 20, lime 5, iron 20.  ■
   When the lava is once thrown out of the
 crater, it rolls in large rivers down the side
 ofthe mountain to a certain distance, which
 forms the currents of  lava, the  volcanic
 causeways &c.  The surface of the  lava
 cools, and forms a solid crust, under which
 the liquid lava flows.  After the eruption,
 this crust sometimes remains, and forms
 hollow galleries, which Messrs. Hamilton
 and Ferber have visited; it is in these hol-
 low places that the sal ammoniac, the mu-
 riate of soda, and other substances sublime.
 A lava  may be turned out of its course by
 opposing banks or  dykes against  it:  this
 was done in 1669 to save Catania; and Sir
 William Hamilton proposed it to the king
 of Naples to preserve Portici.
   The currents of lava  sometimes  remain
 several years in cooling.  Sir William Ha-
 milton  observed, in 1769, that  the  lav
 which flowed in 1766 was still smoking in
 some places.
   Lava is  sometimes swelled Up and po-
 rous.  The lightest is called pumice-stone.
   The substances thrown out by volcanoes
 are not altered by fire.  They eject native
 substances, such as  quartz,  crystals of
 amethyst, agate, gypsum, amianthus,  feld-
 spar, mica, shells, schorl, &c.
   The fire of volcanoes is seldom strong
 enough to vitrify the matters it throws out.
 We know  only of the yellowish capillary
 and flexible glass thrown out by the volca-
 noes of the island of Bourbon, on the 14th
 of May 1766, (M. Commerson), and the la-
 pis gallinaceus  ejected by  Hecla.    Mr.
 Egorfrigouson, who is  employed by the ob-
 servatory at Copenhagen, has settled in
 Iceland, where he uses a mirror of a tele-
 scope, which he has made out of the black
 agate of Iceland.
  The slow operation of time decomposes
 lavas, and  their remains are very  proper
 for vegetation.  The fertile island of Sicily
 has been every where volcanized. Chaptal
 observed several ancient volcanoes at pre-
 sent cultivated;  and the line which sepa-
 rates the other earths from the volcanic
 earth, constitutes the  limit of vegetation.
 The ground over the ruins of Pompeia is
 highly  cultivated.  Sir William Hamilton
 considers subterranean fires as the great
 vehicle  used by nature  to extract  virgin
 earth out of the bowels of the globe, and
 repair the exhausted surface.
  The decomposition of lava is very slow.
 Strata of vegetable earth, and pure lava, are
occasionally found applied one over  the
other; which denote eruptions made at dis«
                     42 
                 WAD     .

tances of time very remote from each other,
since in some instances it appears to have
required nearly two thousand years before
lava was fit to receive the plough.  In this
respect, however, lavas differ very widely,
so that our reasoning from them must at
best be very vague.  An argument has been
drawn from this phenomenon to prove the
antiquity of the globe: but the silence of
the most ancient authors concerning the
volcanoes of the kingdom of France, of
which we find such frequent traces, indi-
cates that tliese volcanoes have been extin-
guished from time immemorial;  a circum-
stance which carries  their existence to a
very distant period.  Beside this,  several
thousand years of connected observations
have  not afforded any remarkable change
in Vesuvius or JEtna; nevertheless these
enormous mountains are all volcanized,
and consequently  formed of strata  applied
one upon the other.  The prodigy becomes
much more striking, when we observe, that
all the surrounding country, to very great
distances, has been thrown out of the bow-
els of the earth.
  The height of Vesuvius above the level
of the sea is three  thousand six hundred
and fifty-nine feet; its circumference thirty-
four thousand four hundred and forty-four.
The height of JEtna is  ten thousand and
thirty-six feet; and its circumference, one
hundred and eighty thousand.
  The various volcanic products  are appli-
cable to several uses.
  1. The pouzzolano is of admirable use
for building in the water: when mixed with
lime it speedily fixes itself; and water does
not soften it, for it becomes continually
harder and  harder.   Chaptal has  proved
              WAT

that oxided ochres afford the same advaru
tage for this  purpose; they are made into
balls, and baked in a potter's  furnace in
the usual manner.  The experiments made
at Sette, by  the commissary of the  pro-
vince, prove, that they may be substituted
with the greatest advantage instead of the
pouzzolano of Italy.
  2. Lava is likewise susceptible of vitrifi-
cation; and in this  state it may be blown
into opaque bottles of the greatest light-
ness,  which Chaptal says he has  done at
Erepian and at Alais.  The very hard lava,
mixed in equal parts with wood-ashes and
soda, produced, he says, an excellent green
glass.  The bottles made of it were  only
half the weight of common bottles, and
much stronger, as was proved by Chaptal'i
experiments, and those which M. Joly de
Fleury ordered to be made under his ad-
ministration.
  3. Pumice-stone  likewise  has its uses;
it is more  especially used to polish most
bodies which are somewhat hard.  It is
employed in the mass or in powder, accor.
ding to the intended purpose. Sometimes,
after levigation,  it is mixed with water to
render it softer,
  * Volcanite.   Augite.*
  * Vulpenite.   Colour grayish-white.
Massive.   Splendent.   Fracture foliated.
Fragments rhomboidal.  In distinct granu-
lar  concretions.  Translucent on the edges.
Soft.  Brittle.  Sp. grav.  2.878.  It melts
easily before  the  blow-pipe  into  a white
opaque enamel.  Its constituents are, sul-
phate of lime 92, silica 8.  It occurs along
with granular  foliated limestone at Vulpi«
no,  in Italy.*
w
• TTJTACKE.  A mineral substance inter-
   TV  mediate between clay and basalt.
It is  sometimes simple; but when it in-
clines to basalt, it contains hornblende and
mica.  It  is sometimes spotted, and these
spots are unformed crystals of hornblende,
resembling the unformed crystals of feld-
spar in certain varieties of porphyry. It ne-
ver contains augite or olivine. When it ap-
proaches to an amygdaloid, it is vesicular.
Its colour is greenish-gray.  Massive and
vesicular.  Dull. Opaque. Streak shining.
Soft.  Easily frangible.   Sp. gr. 2.55 to 2.9.
Fuses like basalt.  It seldom contains  pe-
trifactions.  It occurs  sometimes in beds
and  veins, and these  veins contain very
small portions  of ores of different kinds,
as bismuth,  silver-glance, and magnetic
ironstone.*
   Wadd. This name is given to plumba-
go, or black-lead.
  ■Wadd Black.  An  ore of manganese
found in Derbyshire.  It is remarkable for
the property of taking fire when mixed with
linseed oil.
  Wash.  The technical term for the fer-
mented  liquor,  of whatever  kind, from
which  spirit is  intended to be distilled.
See Alcohol and Distillation.
  Water. Itis scarcely necessary to give
any definition or description of this univer-
sally known fluid.   It is a very transparent
fluid, possessing a moderate degree of acti-
vity  with regard to organized substances,
which  renders it friendly to  animal and
vegetable life, for both which  it  is indeed
indispensably necessary.  Hence it acts but
slightly on  the  organs of sense, and is
therefore said to  have neither taste nor
smell.   It appears to possess considerable
elasticity, and yields ia a perceptible de«
gree to  the pressure of air in the conden 
WAT                              WAT
 sing machine, as Canton proved, by inclu-
 ding it in an open glass vessel with a nar-
 row neck.
   The solubility or insolubility of bodies
 in this fluid composes a large part of the
 science of chemistry.  See Salt.
   * The habitudes of water with heat have
 been detailed under  Caloric and Tempera-
 ture.*
   Water  is not only the common measure
 of specific gravities, but the tables of these
 may be  usefully employed  in the admea-
 surement of irregular solids; for one cubic
 foot is very nearly equal to 1000 ounces
 avoirdupois.   The numbers of the table
 denoting the specific gravities, do  there-
 fore denote likewise the number of ounces
 avoirdupois  in a cubic  foot of each sub-
 stance.
   Native water  is  seldom, if ever, found
 perfectly pure. The waters that flow within
 or upon . the surface of the earth, contain
 various earthy, saline, metallic, vegetable,
 or animal particles, according to the sub-
 stances over or through  which they pass.
 Rain and snow waters are much purer than
 these, although they also contain whatever
 floats in the air, or  has been exhaled along
 with the watery vapours.
   The purity of water  may be  known  by
 the following marks or  properties of pure
 water:—
   1. Pure water  is lighter than water that
 is not  pure.
   2. Pure water  is more fluid than  water
 that is not pure.
   3. It has no colour, smell, or taste.
   4. It wets more  easily than  the waters
 containing metallic  and earthy salts, called
 hard waters, and feels softer when touched.
   5. Soap, or a solution of soap in alcohol,
 mixes  easily and  perfectly with it.
   6. It is not rendered turbid by adding to
 it a solution of gold in aqua regia, or a  so-
 lution of  silver, or of lead, or of mercury,
 in nitric  acid,  or a solution of  acetate of
 lead in water.
   For the habitudes  of  water with saline
 matter, see Salt,  and the different sub-
 stances.
   Water was, till modern times, considered
 as an elementary or simple substance.
   Previous to the month of October 1776,
 the celebrated Macquer, assisted by M. Si-
 gaud de la Fond, made an experiment  by
 burning hydrogen gas in a bottle, without
 explosion, and holding a white china saucer
 over the flame.   His  intention appears  to
 have been that of ascertaining whether any
 fuliginous; smoke was produced, and he ob-
 serves, that the saucer remained perfectly
 clean and white,  but  was moistened with
perceptible drops of a clear fluid; resem-
bling water; and  which, in fact, appeared
to him and his assistant, to be nothing but
 pure water.
   He does not  say whether any test was
 applied to  ascertain this purity, neither
 does he make any remark on the fact.§
   In the month of September 1777, Messrs.
 Bucquet and Lavoisier, not being acquaint-
 ed with the fact, which is incidentally and
 concisely mentioned by Macquer, made an
 experiment to discover  what is produced
 by the combustion of hydrogen. They fired
 five or six pints of hydrogen in an open and
 wide-mouthed bottle, and instantly poured
 two ounces of lime-water through the flame,
 agitating the bottle during the time the com-
 bustion lasted.  The result of this experi-
 ment showed, that carbonic acid was not
 produced. ||
   Before  the month of April 1781,  Mr.
 John Warltire, encouraged by  Dr. Priest-
 ley, fired  a mixture of common air and hy-
 drogen gas in a close copper vessel, and
 found its  weight diminished. Dr. Priestley,
 likewise,  before  the same period, fired a
 like mixture of hydrogen and oxygen gas
 in a closed glass vessel, Mr. Warltire being
 present.  The inside of the vessel, though
 clean  and dry before, became dewy, and
 was lined with a sooty substance.*  These
 experiments were afterwards repeated by
 Mr. Cavendish  and Dr.  Priestley; and  it
 was found, that the diminution of weight
 did not take place, neither  was the sooty
 matter perceived.^  These circumstances,
 therefore, must have arisen from some im-
 perfection in the apparatus or materials
 with which the  former experiments were
 made.
   It was in the  summer of the year 1781,
 that Mr.  Henry Cavendish was busied in
 examining what becomes of the air lost by
 combustion, and made those valuable expe-
 riments, which were read before the Royal
 Society on the 15th of January 1784.§§ He
 burned 500,000 grain measures of hydrogen
 gas, with about 2$ times the. quantity of
 common air, and by causing the burned air
 to pass tlirough  a glass  tube eight feet in

   $  Dictionnaire de Chymie,  2d edition,
 Paris, 1778.  Art. Gas Inflammable, vol. ii.
 p. 314, 315.
   ||  Acad. Par. 1781, p. 470.
   *  Priestley, v. 395.
   If Phil. Trans, lxxiv. 126.  Dr. Priestley
 supposed  the sooty matter to be part of the
 mercury used in filling  the  vessel; Phil.
 Trans, lxxiv. 332.
  §§ Mr. Lavoisier relates, that Dr. Blag-
 den, Sec. R. S. (who was present at the per-
 forming of the capital experiment of burn-
 ing hydrogen and oxygen gas in a closed
 vessel on  the 24th June  1783,)  informed
 him, that Mr. Cavendish had already done
 the same thing, and obtained water.  See
 the  Memoirs of  the  Royal  Academy  at
 Paris for 1781, p. 472j also Phil. Trans, vol,
lxxiv. p. 134. 
WAT                              WAT
length, 135 grains of pure water were con-
dtnsed.  He also exploded  a mixture of
19,500 grain measures of oxygen gas, and
37,000 of hydrogen, in a close vessel.  The
condensed liquor was found to contain a
small portion of nitric acid, when the mix-
ture of the air was such, that the burned air
still contained a considerable proportion of
oxygen.  In this case it  may be presumed,
that some of the oxygen combines with a
portion of nitrogen  present.
   In the mean time, M. Lavoisier continu-
cd his researches, and during the winter of
1781-1782, together with  M.  Gingembre,
he filled a bottle of six pints with hydrogen,
which being fired, and two ounces of lime-
water poured in, w:.s instantly stopped with
a cork, through which a flexible tube com-
municating with a vessel of oxygen was
passed.  The inflammation ceased, except
at the orifice of the tube, through  which
the oxygen was pressed, where a beautiful
flame appeared.  The combustion continu-
ed a considerable time, during which  the
lime-water was agitated in the bottle. Nei-
ther this, nor the same experiment repeat-
ed with pure water, and with a weak solu-
tion of alkali instead of lime-water, afford-
ed the information  sought after, for  these
substances were not at all altered.
   The inference of Mr. Warltire, respect-
ing the moisture on the inside ofthe glass,
in which Dr. Priestley first fired hydrogen
 and common air, was,  that  these airs, by
 combustion, deposited  the  moisture they
 contained.   Mr. Watt, however, inferred
 from these  experiments, that water is  a
 compound of the burned airs, which have
 given out their latent heat by combus-
 tion, and communicated his sentiments ta
 Dr. Priestley in  a letter dated April 26.
 1783.§
   It does not appear,|| that the composition
 of water was known or  admitted in France,
 till the  summer of 1783, when  M. Lavoi-
 sier and M. de la Place, on the 24th of
 June, repeated the experiment of burning
 hydrogen and oxygen in a glass vessel over
 mercury, in a still greater quantity than had
 been burned by Mr. Cavendish.  The re-
 sult was nearly five gros of pure  water.*
  M. Monge made a similar experiment  at
  Paris, nearly at the same time, or perhaps
  before.
    This assiduous and accurate philosopher
  then proceeded,  in conjunction with M.
  Meusnier,  to pass  the  steam  of water
  through a red-hot  iron  tube, and found that

    § Phil. Trans, vol. lxxiv.  p. 330.
    || Compare Phil. Trans, vol. lxxiv. p. 138,
  with the Memoirs of the  Royal Academy at
  Paris for 1781, pages 472 and 474.
    * The ounce  poids de marc being 472.2
   grains troy, this quantity will be 295  Eng-
   lish grains.
the iron was oxidized, and hydrogen dis-
engaged; and  the steam  of  water being
passed over a variety of other combustible
or oxidable substances, produced similar
results, the water disappearing, and hydro-
gen being disengaged.  These capital ex-
periments were accounted for by M. La-
voisier, by supposing the  water to be de-
composed into its component parts, oxygen
and hydrogen, the former of which unites
with the ignited substance, while the latter
is disengaged.
   The grand  experiment of the composi-
tion of water by Fourcroy, Vauquelin, and
Seguin, was begun on \\ ednesday, May 13,
 1790, and was finished on  Friday, the 22d
of the same month.   'The combustion was
kept up  185 hours with little interruption,
during which time  the machine was not
quitted for a moment. The experimenters
alternately refreshed themselves when fa-
tigued, by lying for  a few hours on mat-
 tresses in the  laboratory.
   To  obtain  the hydrogen,  1.  Zinc was
melted and rubbed into a  powder in a very
 hot mortar.  2. This metal was  dissolved
 in concentrated  sulphuric   acid  diluted
 with  seven parts of water.   The air pro-
 cured was made to pass  through caustic
 alkali.   To obtain the oxygen, two pounds
 and a half of crystallized  hyperoxymuriate
 of potash were distilled, and  the  air was
 transferred through caustic alkali.
   The volume of hydrogen employed was
 25963.568 cubic inches,  and the  weight
 was 1039.358 grains.
   The volume of oxygen was 12570.942,
 and the  weight was 6209.869 grains.
   The total weight of both  elastic fluids
 was 7249.227.
   The weight of water obtained was 7244
 grains, or 12 ounces 4 gros 45 grains.
   The weight of water which should have
 been obtained was 12 ounces 4 gros 49.227
 grains.
   The deficit was 4.227 grains.
   The quantity of azotic  air  before the ex-
 periment was 415.256 cubic inches, and at
 the close of it 467.  The excess after  the
 experiment was consequently 51.744 cubic
 inches.   This augmentation is to be attri-
 buted, the academicians think, to the small
 quantity of atmospheric  air in the cylin-
 ders  of the gasometers,  at  the time  the
 other airs were  introduced.  These addi-
 tional 51 cubic inches could not arise from
 the hydrogen, for experiment showed, that
 it contained no azotic air.  Some addition
 of this  last fluid, the experimenters think,
 cannot  be avoided, on account of the con-
 struction of the machine.
    The  water  being  examined,  was found
  to be as pure as distilled water.  Its  spe-
  cific gravity to distilled water was as 1867L
  18670.
    * The decomposition  of water is most 
                 WAT

elegantly effected by Electricity; which
see.
  The composition of water  is best de-
monstrated by exploding 2 volumes of hy-
drogen and 1 of oxygen, in the eudiometer.
They disappear totally, and pure water re-
sults.  A cubic inch of this liquid at 60°,
weighs 252.52 grains, consisting of
        28.06 grains hydrogen, and
       224.46       oxygen.
The bulk ofthe former | 1325 cubic .   h
  gas is              3
That of the latter is     662
                       1987
  Hence there is a condensation of nearly
two thousand volumes into one;  and one
volume of water contains 662 volumes of
oxygen.   The prime equivalent of water is
1.125; composed of  a  prime of oxygen =
1.0 -f- a  prime of hydrogen = 0.125; or 9
parts by weight of water, consist of 8 oxy-
gen -f- 1 hydrogen.*
   Water of Crystallization.  Many
salts require a certain proportion of water
to  enable them to retain  the crystalline
form, and this is called their water of crys-
tallization.    Some  retain this so feebly,
 that it flies off on exposure to the air,  and
they fall to powder.  These are the efflo-
 rescent salts.  Others have so great an af-
 finity for water, that their crystals attract
 more from the air, in  which they dissolve.
 These are the deliquescent.
    Waters (Mineral).  The  examina-
 tion of mineral waters with a view  to  as-
 certain their ingredients, and thence their
 medical qualities and the means of com-
 pounding them artificially, is an  object of
 considerable  importance  to society.  It is
 likewise a subject which deserves  to be
 attended to, because it affords  no mean
 opportunity for the agreeable practice of
 chemical skill.  But this investigation  is
 more especially of importance to the daily
 purposes of life, and the success of manu-
 factures.  It cannot but be an interesting
 object,  to ascertain the  component parts
 and  qualities of  the waters daily  con-
 sumed by  the inhabitants of large  towns
 and vicinities.  A very minute portion of
 unwholesome matter, daily taken, may con-
 stitute the principal  cause of the  differ-
 ences in salubrity, which are  observable in
 different places.  And with regard to ma-
 nufactures, it  is well known to the brewer,
 the paper-maker, the  bleacher, and a vari-
 ety of other  artists, of how  much conse-
 quence it is to them, that this fluid should
 either be pure, or at least not contaminated
 with such principles as tend to injure the
 qualities of the articles they  make.  This
 analysis has accordingly  employed the  at-
 tention  of the first chemists.  Bergmann
 has written an express treatise on the sub-
 ject, which may be found in  the  first  vo-
 lume of the English translation of his Es-
              WAT

says.  Kirwan published a valuable volume
on the analysis of waters.
  The topography of the place where these
waters rise is the first thing to be  consi-
dered.  By examining the ooze formed by
them, and the  earth  or  stones through
which they are strained and filtered, some
judgment may be formed of their contents.
In filtering through the earth, and meander-
ing on  its surface, they take  with them
particles of various kinds, which their ex-
treme attenuation renders capable of being
suspended in the fluid that serves for their
vehicle.  Hence we shall  sometimes  find
in these waters, siliceous,  calcareous, or
argillaceous  earth;  and at other  times,
though less frequently, sulphur, magnesian
earth, or, from  the decomposition of car-
bonated iron, ochre.
   The following are the ingredients  that
may  occur in mineral waters:
   1.  Air is contained in by far the greater
 number of mineral waters: its proportion
 does not exceed l-28th of the  bulk of the
 water.
   2.  Oxygen gas was first detected  in wa-
 ters by Scheele.  Its quantity is usually in-
 considerable; and it is incompatible  with
 the presence of sulphuretted hydrogen gas
 or iron.
   3. Hydrogen  gas was first detected in
 Buxton water by Dr. Pearson.   Afterward
 it was discovered in Harrowgate waters by
 Dr.  Garnet, and in  those of Lemington
 Priors'by Mr. Lambe.
   4. Sulphuretted hydrogen gas constitutes
 the most conspicuous  ingredient in those
 waters, which  are distinguished  by the
 name of  hepatic or sulphureous.
   The only  acids hitherto found in waters,
 except in combination with a base, are the
 carbonic, sulphuric, and boracic.
   5. Carbonic acid was first discovered  in
 Pyrmont water  by Dr. Browniigg.  It  is
 the  most common ingredient in mineral
 waters; 100  cubic inches of the water ge-
 nerally containing from 6 to 40 cubic inches
 of this acid  gas. According to WestrUmb,
 100 cubic inches of Pyrmont water contain
 187 cubic inches of it, or almost double its
 own bulk
   6. Sulphurous acid has been observed in
 several of the hot mineral waters in Italy,
 which are in the neighbourhood of volca-
 noes.
   7. The boracic acid has also been ob-
 served in some  lakes in Italy.
   The only  alkali which has been observed
 in mineral  waters, uncombined, is soda;
 and  the only earthy bodies are silex and
 lime.
    8. Dr. Black  detected  soda in the hot
 mineral waters of Geysser and  Rykum  in
 Iceland; but in most other cases the  soda
 is combined with carbonic acid.
   9. Silex was first discovered in waters by 
WAT
WAT
Bergmann,  It was afterward detected in
those of Geysser and Rykum by Dr. Black,
and in those of Karlsbad by Klaproth. Has-
senfratz observed it in the  waters of Pou-
gues, as Breze' did in those of Pu.  It has
been found also in many other mineral wa-
ters.
   10. Lime is said to have been found un-
combined in some mineral waters; but this
has not been proved in a satisfactory man-
ner.
   The only salts hitherto found in mineral
waters are the following sulphates, nitrates,
muriates, carbonates, and borates; and of
these the carbonates  and muriates occur
by far most commonly, and the borates and
nitrates most rarely.
   11. Sulphate of soda is not uncommon,
especially in those mineral waters  which
are distinguished by the epithet saline.
   12. Sulphate of ammonia is found in mi-
neral waters near volcanoes.
   13. Sulphate of lime is exceedingly com-
mon in water.  Its presence seems to have
been first detected by Dr. Lister in 1682.
   14. Sulphate  of magnesia is almost con-
stantly an ingredient in those mineral wa-
ters which have purgative  properties.  It
was detected in Epsom waters in 1610, and
in 1696 Dr. Grew published a treatise on it.
   15  Alum is sometimes found in mineral
Waters, but it is exceedingly rare.
   16. Sulphate of iron occurs sometimes in
volcanic mineral waters, and has even been
observed in other places.
   17. Sulphate of copper is only found in
the waters which issue from copper mines.
   18. Nitre has been found in some springs
in Hungary, but it is exceedingly uncom-
mon.
   19. Nitrate  of lime was first detected in
water by Dr. Home, of Edinburgh, in 1756.
It is said to occur in some  springs in the
sandy deserts of Arabia.
  20. Nitrate  of magnesia is said  to have
been found in some springs.
  21. Muriate of potash is uncommon; but
it has lately been discovered in the mine-
ral springs of  Uhleaborg in  Sweden, by
Julin.
   22. Muriate of soda is so extremely com-
mon in mineral waters, that  hardly a single
spring has been analyzed without detecting
some of it.
   23. Muriate  of  ammonia is uncommon,
but  it has been found in some  mineral
springs in Italy and in Siberia.
   24. Muriate of barytes is still more un-
common,  but  its presence in mineral wa-
ters has been announced by Bergmann.
   25 and  26.  Muriates of lime and magne-
sia are common ingredients.
   27. Muriate of alumina has been observed
by Dr. Withering, but it is very uncommon.
   28. Muriate of manganese was mention-
ed by Bergmann as sometimes occurring
in mineral waters.  It has lately been de-
tected by Lambe in the waters of Leming-
ton Priors, but in an extremely limited pro-
portion.
  29. The presence of carbonate of potash
in mineral waters has been mentioned by
several chemists; if it do occur, it must be
in a very small proportion.
  30. Carbonate of soda is, perhaps, one of
the  most common ingredients of these li-
quids, if we except common salt and car-
bonate of lime.
  SI. Carbonate of  ammonia has been dis-
covered in waters, but it is uncommon.
  32. Carbonate of lime is found in almost
all waters, and is usually held in solution
by an excess of acid.   It appears from the
different experiments of chemists, as stated
by Mr. Kirwan, and especially from those
of Berthollet,  that water saturated with
carbonic acid is capable of holding in so-
lution  0.002  of carbonate of lime.  Now
water saturated with carbonic acid, at the
temperature of 50°, contains very nearly
0.002 of its weight of carbonic acid. Hence
it follows, that carbonic acid, when present
in such quantity as  to saturate waters, is
capable of holding its own weight of car-
bonate of lime in solution.  Thus we see
1000 parts by  weight of water,  when it
contains two  parts of carbonic acid, is ca-
pable of  dissolving two parts of carbonate
of lime.  When the proportion of water is
increased, it is  capable of holding the car-
bonate of lime in solution, even when the
proportion  of carbonic acid united with it
is diminished.  Thus  24000 parts of water
are capable of holding two parts of carbo-
nate of lime in solution, even when  they
contain only one part of carbonic acid. The
greater the proportion of water, the smaller
proportion of carbonic acid is necessary to
keep the lime in solution; and when the wa-
ter is increased to a certain proportion, no
sensible excess of carbonic acid is necessa-
ry.   It ought  to be remarked also, that wa-
ter, however  small a quantity of carbonic
acid it contains, is capable of holding car-
bonate of  lime in solution, provided the
weight of  the  carbonic  acid present ex-
ceed that of the lime.  These observations
apply equally to the other earthy carbonates
held in solution by mineral waters.
  33. Carbonate of magnesia is  also very
common  in mineral waters, and is almost
always accompanied by carbonate of lime.
  34. Carbonate of alumina is said to have
been found in waters, but its presence has
not been properly ascertained.
  35. Carbonate of iron is by no means un-
common; indeed it forms the most remark.
able ingredient in those waters, which are
distinguished by the epithet of chalybeate.
  36. Borax exists in some lakes in Persia
and  Thibet, but the nature qf these waters
has  not been ascertained. 
WAT                              WAT
  37 and 38. The hydrosulphurets of lime
and of soda have been frequently detected
in those waters which  are  called sulphu-
rous, or hepatic.
  Mr. Westrumb says, that all sulphurous
waters contain more or less hydrosulphu-
ret of lime.
  To detect this he boiled the mineral wa-
ter, excluding the contact of atmospheric
air, to expel  the sulphuretted hydrogen
gas and carbonic, acid.  Into the water thus
boiled he  poured  sulphuric  acid,  when
more sulphuretted hydrogen gas was evol-
ved, and sulphate of lime was thrown down;
fuming nitric acid, which separated from
it sulphur; and oxalic acid, which expelled
sulphuretted hydrogen, and formed oxalate
of time.   The  water evaporated in open
vessels let fall sulphate of lime, and gave
out sulphuretted hydrogen gas.
  To ascertain the quantity of sulphuretted
hydrogen gas and carbonic acid, Mr. West-
rumb proceeded as follows:  He introduced
the  sulphurous water into a  matrass, till
it was filled to a certain point,  which he
marked; fitted to it a  curved tube,  which
terminated in a long  cylinder; filled  this
cylinder with lime-water for the one expe-.
riment, and with  acetate of lead, with ex-
cess  of acid, for the other; luted the appa-
ratus, and boiled the water till  no more
gas was expelled.  When  the lime-water
is used, carbonate of lime is precipitated
in the proportion of 20 grains to every 10
cubic inches  of carbonic acid gas; when
the solution of acetate of lead,  hydrosul-
phuret of lead is thrown down in the  pro-
portion of 19 grains to 10 cubic  inches  of
 sulphuretted hydrogen gas.
   Beside these substances, certain vegeta-
 ble and animal  matters have been occa-
 sionally observed in mineral  waters.  But
 in most cases, these are rather to be  con-
 sidered in the light of accidental mixtures,
 than of real component parts of the  waters
 in which they occur.
   From this  synoptical view of the differ-
 ent ingredients contained in mineral wa-
 ters, it is evident, that these substances
 occur in two different distinct states, viz.
 1.  As being suspended in them;  and 2- As
 being dissolved in them chiefly in the form
 of a salt.
   The investigation of mineral waters con-
 sists, 1. In the examination of them by the
 senses:  2. In  the  examination of them  by
 reagents:  3.  In the analysis properly  so
 called.
   The examination by the senses consists
 in observing the effect of  the water as to
 appearance, smell,  and taste.
    The appearance of the water, the  instant
 in which it is pumped out of the well, as
 well as after it has stood for some time,
 affords several indications, from which we
 are enabled to form a judgment concern-
ing its contents.  If the water be turbid at
the well, the substances are  suspended
only, and not dissolved; but if the water
be clear and transparent at the well,  and
some time intervenes  before  it becomes
turbid, the contents are dissolved by means
of carbonic acid.
  The presence of this gas is likewise in-
dicated by small bubbles,  that rise  from
the bottom of the  well, and  burst in the
air while they are making their  escape,
though the water at the same time  perhaps
has not an acid taste.  This  is the  case,
according to Count Razoumowski, with re-
spect  to  the tepid spring in Vallais, and
the cold vitriolated chalybeate springs at
Astracan.  But the most evident proof of
a spring containing carbonic acid is the
generation of bubbles on  the water  being
shaken;  and their bursting  with  more or
less  noise,  while  the air is making  its
 escape.
   The sediment deposited by the  water in
the well is likewise to be examined: if it
be yellow, it indicates the presence of iron;
 if black, that of iron  combined with sul-
 phur; but chalybeate waters  being seldom
 sulphuretted, the  latter occurs very rarely.
 As to the colour of the water itself, there
 are  few instances where this can  give any
 indication of its contents, as there are not
 many substances that colour it.
   The odour of the  water serves chiefly
 to discover  the presence  of sulphuretted
 hydrogen in it: such waters as contain this
 substance have a peculiar fetid smell, some-
 what resembling rotten eggs.
   The taste of a  spring, provided  it be  •
 perfectly ascertained by  repeated  trials,
 may afford  some  useful indications with
 respect to the contents.  It may be made
 very sensible by tasting water, in which the
 various salts that are usually found in such
  waters are dissolved in various proportions.
  There is no certain dependence, however,
 to be placed on this mode of investigation;
  for in many springs, the taste of  sulphate
  of soda is disguised by that of the sea salt
  united  with it.  The water too is not only
  to be tasted at the spring, but after it has
  stood for some time. This precaution must
  be  particularly observed  with respect  to
  such waters as are impregnated with car-
  bonic acid;  for the other substances con-
  tained in them make no impression  on  the
  tongue, till the carbonic acid has made its
  escape;  and it is for the same reason, that
  these waters must be evaporated in part,
  and then tasted again.
    Though the specific gravity of any water
  contributes but very little towards  deter-
  mining its contents,  still it may not be en-
  tirely useless to know the specific weight
  of  ttie  water, the situation of the spring,
  and the kind of sediment deposited by it.
    The  examination of the water by means 
WAT
WAT
 of reagents shows what they contain, but
 not how much of each principle.   In many
 instances this is as much as the inquiry
 demands; and it is always of use to direct
 the proceedings in the proper analysis.
   It is absolutely necessary  to  make  the
 experiment with water just taken up from
 the spring, and afterward with such as has
 been exposed for some hours to  the open
 air; and sometimes a third essay is to be
 made with a portion of the water that has
 been boiled and afterward filtered. If the
 water contain but few  saline particles,  it
 must be evaporated; as even  the most sen-
 sible reagents do not in the least affect it,
 if the salts, the presence of which is to be
 discovered  by them, are diluted with too
 great a quantity of water.  Now, it  may
 happen, that a water shall be impregnated
 with a considerable number of saline par-
 ticles of different kinds,  though some of
 them may be present in too small a quan-
 tity; for which reason the water must  be
 examined a second time, after having been
 boiled down to three-fourths.
   The substances of which the  presence
 is discoverable by reagents, are:—
   1. Carbonic acid. When this is not com-
 bined with any base, or not with sufficient
 to neutralize it, the addition of lime-water
 will throw down a precipitate soluble with
 effervescence in muriatic  acid.   The infu-
 sion of litmus is reddened by it;  but  the
 red colour gradually disappears,  and  may
 be again restored by the addition of more
 ofthe mineral water.  When boiled it loses
 the property of reddening the infusion of
 litmus. According  o Pfaff, the most sen-
 sible test of this acid is acetate of lead.
  2. The mineral acids, when present  un-
 combined in water, give the infusion of lit-
mus a permanent red, even though \Jie wa-
ter has been boiled. Bergmann has shown,
that paper stained with litmus is reddened
when dipped into water  containing -jTJT
of sulphuric acid.
  3. Water containing sulphuretted hydro-
gen gas is distinguished by the  following
properties:  It  exhales the peculiar odour
of sulphuretted hydrogen gas.  It reddens
the infusion of litmus fugaciously. It black-
 ens paper dipped into a solution of lead,
 and precipitates the nitrate of silver black
 or brown.
  4. Alkalis, and alkaline and earthy  car-
bonates, are distinguished by the following
 tests: The infusion of turmeric, or paper
 stained with turmeric, is rendered brown
 by alkalis; or reddish-brown, if the quanti-
ty be minute.  This  change is  produced
 when the soda in  water amounts  only  to
 ■yjpfpart. Paper stained with Brazilwood,
 or the infusion of Brazil wood, is rendered
 blue; but this change  is produced also by
 the alkaline and earthy carbonates. Berg-
 mann ascertained, that water containing
 yjrVr  part of carbonate of soda, renders
 paper  stained with  Brazil wood blue.  Lit-
 mus paper reddened by vinegar is restored
 to its  original  blue colour.  This change
 is produced by the alkaline and earthy car-
 bonates also.  When these changes are fu-
 gacious, we may conclude, that the  alkali
 is ammonia.
   5. Fixed alkalis exist in  water that occa-
 sions a precipitate with muriate of magne-
 sia after being boiled   Volatile alkali  may
 be distinguished by the smell; or it may be
 obtained in the receiver by distilling a  por-
 tion of the water gently, and then it may be
 distinguished by the above tests.
  6. Earthy trod metallic  carbonates  are
 precipitated by boiling the water contain-
 ing them; except  carbonate of magnesia,
 which  is precipitated but imperfectly.
  7. Iron is  discovered by  the  following
 tests:—The addition of tincture of galls
 gives water, containing iron, a purple or
 black colour.  This test indicates the pre-
 sence of a very minute portion of iron. If
 the tincture have no effect  upon the water,
 after boiling, though it colours it before,
 the iron is in the state  of a carbonate. The
 following observations of Westrumb on the
 colour  which iron gives to  galls, as modifi-
 ed by  other bodies, deserve  attention.  A
 violet  indicates  an  alkaline carbonate, or
 earthy  salt.  Dark purple  indicates  other
 alkaline salts.   Purplish-red indicates  sul-
phuretted hydrogen gas.   Whitish,  and
then black,  indicates   sulphate  of  lime.
Mr. Phillips has lately ascertained, that,
while the iron  is little oxided, the presence
of lime rather facilitates the application of
this test;  but the lime prevents the test
from acting, provided the iron be conside-
rably oxidized.  The prussian alkali  occa-
sions a blue precipitate in water containing
iron.   If an alkali be present, the blue pre-
cipitate does not appear  unless the  alkali
is saturated with an acid.
  8. Sulphuric  acid exists in waters that
form a precipitate with the following solu-
tions:—muriate, nitrate, or acetate of ba-
 rytes, strontian, or  lime, or nitrate or ace-
 tate of lead.   Of these the most powerful
 by far is  muriate of barytes, which is capa-
 ble of  detecting the presence of sulphuric
 acid uncombined, when it does not exceed
 the millionth part of the water. Acetate
 of lead is next in  point of power.   The
 muriates  are more powerful than the ni-
 trates.  The calcareous salts are least pow-
 erful.  All these tests are capable of indi-
 cating  a much smaller proportion  of un-
 combined sulphuric acid, than when it is
 combined with  a  base.   To render  mu-
 riate of barytes a certain test of sulphuric
 acid,  the following precautions must be
 observed:—The muriate must be diluted;
 the alkalis or  alkaline carbonates,  if the
 water  contain arv, must be previously sa- 
WAT                                 WAT
turated with muriatic acid; the precipitate
must be insoluble in muriatic acid; if bo-
racicacid be suspected, muriate of stron-
tian must be tried, which is  not precipi-
tated  by boracic  acid.   The  hydrosul-
phurets  precipitate barytic solutions, but
their presence is easily discovered by the
smell.
   9.  Muriatic acid is detected  by nitrate
of silver, which  occasions a white preci-
pitate, or a cloud, in water containing  an
exceedingly  minute portion  of this acid.
To render this test certain, the  following
precautions are necessary:—The alkalis or
carbonates must be previously  saturated
with  nitric  acid.  Sulphuric  acid,  if any
be present,  must be previously removed
by means of nitrate of barytes.   The pre-
cipitate must he insoluble in nitric acid.
Pf'aff says, that the mild nitrate of mercury
is the most sensible test of muriatic acid;
and that the precipitate is not soluble in an
excess of any acid.
   10. Boracic acid is  detected by  means
of acetate of lead, with  which it forms a
precipitate insoluble in acetic acid. But to
render this test certain, the  alkalis and
earths must be  previously saturated with
acetic acid,  and the sulphuric  and muria-
tic acids removed by means of acetate of
strontian and acetate of silver.
   11. Barytes is detected by the insoluble
white precipitate, which it forms with di-
luted sulphuric  add.
   12. Lime  is detected by means of oxalic
acid, which  occasions  a white precipitate
in water  containing a very minute propor-
tion of this earth.  To render this test de-
cisive, the following precautions are ne-
cessary:— The mineral acids,  if any be
present, must be previously saturated with
an alkali. Barytes, if any be present, must
be previously removed by means  of sul-
phuric acid. ' Oxalic acid precipitates mag-
nesia but very slowly, whereas it precipi-
tates lime instantly.
   13. Magnesia and alumina.  The pre-
sence of these earths is ascertained by the
following tests:---Pure  ammonia precipi-
tates them both, and no  other earth, pro-
vided the carbonic acid have been previ-
ously separated  by a fixed alkali, and boil-
in«\   Lime-water  precipitates only these
two earths, provided the carbonic acid be
previously removed, and the sulphuric acid
also, by means of nitrate of barytes
   'The alumina maybe separated from the
magnesia, after both have been precipitated
together, either by boiling the precipitate
in caustic potash,  which dissolves the alu-
mina and leaves  the magnesia; or the pre-
cipitate may be dissolved in muriatic acid,
precipitated by an alkaline carbonate, dri-
ed in the temperature of 100°,  and then
exposed to the action  of diluted muriatic
   Vol.  11.
acid, which dissolves  the  magnesia.with-
out touching the alumina.
   14. Sile\ may be ascertained  by evapo-
rating a portion of water to  dryness;  and
redissohing the  precipitate  in muriatic
acid.  The silex remains behind undissol-
ved.
   By these means we may  detect the pre-
sence of the different substances commonly
found in waters; but as they are generally
combined so as to form salts, it is neces-
sary we should know what these combina-
tions are.  This is a more difficult task,
which Mr. Kirwan teaches us  to accom-
plish by the following methods:—
   1. To ascertain the presence of the  dif-
ferent sulphates.
   The sulphates which occur in water are
seven;  but one of these, namely, sulphate
of copper, is so uncommon, that  it may be
excluded altogether.  The same remark
applies to sulphate of  ammonia. It is  al-
most unnecessary to observe, that no sul-
phate need be looked for,  unless both  its
acid and base have been previously detect-
ed in the water.
   Sulphate of soda may be detected by the
following method:—Free the water to be
exam'uv d of all earthy sulphates, by eva-
porating it to one-half, and  adding lime-
water as long as  any precipitate appears.
By these means the earths  will all be pre-
cipitated except lime, and the only remain-
ing earthy  sulphate will  be sulphate of
lime, which will  be separated  by evapo-
rating the liquid till it becomes concen-
trated, and then dropping into it a little al-
cohol, and, after filtration,  adding a little
oxalic acid.
  With the water  thus purified,  mix solu-
tion of lime.  If a precipitate appear, either
immediately or on the addition  of a little
alcohol, it is a proof, that sulphate of pot-
ash or of soda is present.  Which of  the
two  may be determined, by mixing some
of the purified water with  acetate of  ba-
rytes.  Sulphate of barytes  precipitates.
Filter and evaporate to  dryness. Digest
the residuum in alcohol. It  will dissolve
the alkaline acetate. Evaporate to dryness,
and  the dry salt  will  deliquesce  if it  he
acetate  of potash, but effloresce if  it  be
acetate  of soda.
  Sulphate  of lime  may be  detected  by-
evaporating the water suspected to contain
it to a few ounces.  A precipitate appears,
which, if it be sulphate of  lime, is soluble
in 500 parts of water; and the solution af-
fords a precipitate with the muriate of ba-
rytes, oxalic acid,  carbonate  of  magnesia,
and alcohol.
  Alum may be detected by mixing car-
bonate of lime with the water  suspected
to contain it.  If a precipitate  appear, it
indicates  the presence of alum, or at least
                      43 
WAT
WAT
of sulphate of alumina; provided the water
contains no muriate of barytes or metallic
sulphates.  The first of these  salts is in-
compatible with alum. The second may be
removed by the alkaline prussiates.  When
a  precipitate is produced in water by mu-
riate of lime, carbonate of lime, and muri-
ate of magnesia, we may conclude, that  it
contains alum or sulphate of alumina.
   Sulphate of  magnesia may be detected
by means of hydrosulphuret of  strontian,
Which occasions an  immediate precipitate
with this salt, and with no other; provided
the water be previously deprived of alum,
if any be present, by means of carbonate
of lime, and provided also that it contains
no uncombined acid.
   Sulphate of iron is precipitated from wa-
ter by alcohol, and then it may  be easily
recognized by  its properties.
   2. To ascertain the presence of the dif-
ferent muriates.
   The muriates found in waters amount  to
eight, or to nine  if muriate of iron be in-
cluded.  The  most common by far is mu-
riate of soda.
   Muriate of soda and of potash may be
detected by the following method:—Sepa-
rate the sulphuric acid by alcohol  and ni-
trate of barytes.   Decompose the  earthy
nitrates and  muriates by adding  sulphuric
acid. Expel the  excess  of muriatic and
nitric acids by heat. Separate the sulphates
thus formed by alcohol and barytes-water.
The water thus purified can  contain no-
thing but alkaline nitrates and  muriates.
If it form a  precipitate with acetate of sil-
ver, we may conclude, that it contains mu-
riate of soda  or of potash. To ascertain
which, evaporate  the liquid thus  precipi-
tated to dryness.   Dissolve the  acetate  in
 alcohol, and again evaporate  to dryness.
 The salt will deliquesce, if it be acetate of
 potash;  but  effloresce, if  it be acetate  of
 soda.
   Muriate of  barytes may be  detected  by
 sulphuric acid, as  it is  the  only  barytic
 salt hitherto found in water.
   Muriate of lime may be detected by the
 following method:—Free the  water from
 sulphate of lime and other sulphates,  by
 evaporating it to a  few ounces,  mixing  it
 with alcohol, and adding last of all nitrate
 of barytes, as  long as any precipitate ap-
 pears.   Filter the water; evaporate to dry-
 ness; treat the dry  mass  with  alcohol; eva-
 porate the alcohol to dryness;  and dissolve
 the  residuum in  water.  If this  solution
 give a precipitate with  acetate of silver
 and oxalic acid, it may contain muriate  of
 lime.  It must contain it  in that  case,  if,
 after being treated with carbonate of lime,
 it give no precipitate with ammonia. If the
 liquid  in the  receiver  give  a  precipitate
 with nitrate of silver, muriate of lime  ex-
 isted in the water.
  Muriate of magnesia may be detected
by separating all the sulphuric  acid  by
means of nitrate of barytes.  Filter, evapo-
rate  to dryness,  and treat  the dry mass
with alcohol. Evaporate  the alcoholic  so-
lution  to dryness, and  dissolve  the resi-
duum in water.  The muriate of magnesia,
if the water  contained any,  will be  found
in this solution:  Let us suppose,  that,  by
the tests formerly described, the presence
of muriatic acid and of magnesia, in this
solution, has been ascertained. In that case,
if carbonate of lime  afford  no  precipitate,
and  if sulphuric acid and evaporation,  to.
gether with the  addition of a little alcohol,
occasion no  precipitate, the solution con-
tains only muriate of magnesia.  If these
tests give  precipitates, we  must  separate
the lime which is present by sulphuric acid
and  alcohol, and distil off the acid with
which it was combined. Then the magnesia
is to be separated by the oxalic acid and alco-
hol, and the acid with which it was  united
is to be distilled off. If the liquid  in the
retort give a precipitate with nitrate of
silver, the water contains muriate of mag-
nesia.
  Muriate of alumina may  be  discovered
by  saturating the water, if it  contain  an
excess of alkali, with nitric acid, and  by
separating the sulphuric acid by means of
nitrate of barytes.  If the liquid, thus  pu-
rified, give a precipitate with carbonate of
lime, it contains muriate of alumina. The
muriate of iron or of manganese,  if any be
present, is also decomposed, and  the iron
precipitated by this salt.  The precipitate
may be dissolved in muriatic acid, and  the
alumina,  iron, and  manganese, if they be
present, may be separated by the rules
laid down below.
   3. To ascertain the presence of the  dif-
 ferent nitrates.   The nitrates  but seldom
 occur in  waters; but when they  do, they
 may be detected by the following results:—
   Alkaline nitrates may be  detected  by
 freeing the  water examined from sulphu-
 ric  acid by  means  of acetate of barytes,
 and from muriatic acid by acetate of silver.
 Evaporate the filtered liquid, and treat the
 dry mass with  alcohol;  what the  alcohol
 leaves can consist only of  the alkaline ni-
 trates and acetate of lime.  Dissolve it in
 water. If carbonate of magnesia occasion a
 precipitate, lime is present.   Separate the
 lime by means  of carbonate of magnesia.
 Filter and evaporate to dryness,  and treat
 the dried mass with alcohol.   The  alcohol
 now leaves only the alkaline nitrates, which
 may be easily recognized, and distinguish-
 ed  by their respective properties.
   Nitrate of lime. To detect this salt,  con-
  centrate the water, and mix it with alcohol
  to  separate the sulphates.  Filter, and dis-
  til  off the  alcohol; then separate the  mu-
  riatic acid  by  acetate of silver.  Filter, 
WAT
WAT
evaporate to dryness, and dissolve the resi-
duum in alcohol.  Evaporate to dryness,
and dissolve the dry mass in water.  If this
last solution indicate the presence of lime
by the usual tests, the water  contained ni-
trate of lime.
  To detect nitrate of magnesia, the water
is to  be freed  from sulphates and muri-
ates  exactly as described in the last pa-
ragraph. The liquid thus purified is to be
evaporated to dryness, and the residuum
treated with alcohol.  The alcoholic solu-
tion is to be evaporated  to  dryness, and
the dry  mass dissolved in water.  To  this
solution  potash is to be added, as long as
any precipitate appears.  The solution, fil-
tered, and again evaporated to dryness, is
to be treated with alcohol. If it leave a re-
siduum  consisting  of nitre (the only resi-
duum which it can leave) the water con-
tained nitrate of magnesia.
  Such are the methods by which the pre-
sence of the  different saline contents of
water may be ascertained. The labour of
analysis  may be considerably shortened,
by observing that  the following  salts are
incompatible with each other, and cannot
exist together in water, except in very mi-
nute proportion:—
      Salts.         Incompatible with
               fNitrates of lime  and
Fixed alkaline J   magnesia.
  sulphates   <  j Muriates  of  lime   and
                t.  magnesia.
                 {Alkalis,
                 Carbonate  of magnesia,
                  Muriate of barytes.
                f Alkalis,
                j Muriate of barytes,
Alum         -s Nitrate, muriate, carbo-
                ]   nate of lime,
                V-Carbonate  of magnesia.
                f Alkalis,
Sulphate of    J Muriate of barytes,
  magnesia     j Nitrate  and muriate of
                V.  lime.
                TAlkalis,
Sulphate of iron<  Muriate of barytes,
                \.Earthy carbonates.
_,  . ,.   c     ("Sulphates,
Muriate ot    J Alkal;ie carbonates,
  barytes       ^Earthy carbonates.
                  {Sulphates,exceptoflime,
                  Alkaline carbonates,
                  Earthy carbonates.
Muriate of mag- C Alkaline carbonates,
   nesia         £ Alkaline sulphates.
                  {Alkaline carbonates,
                  Carbonate  of  magnesia
                   and alumina,
                  Sulphates,except of lime,

   Beside the substances above described,
there is sometimes found in  water  a quan-
tity of  bitumen combined with alkali, and
in the state of soap.  In such waters, acids
occasion a coagulation; and the coagulum
collected on a filter discovers its bitumi-
nous nature by its combustibility.
  Water also sometimes  contains extrac-
tive matter; the presence of which may be
detected by means of nitrate of silver. The
water suspected to contain it must be freed
from sulphuric  and nitric acid by  means
of nitrate of lead: after this, if it  give a
brown precipitate with nitrate of silver, we
may conclude that  extractive matter  is
present.
  But it is not sufficient to know that a
mineral water contains certain ingredients;
it is necessary to ascertain the proportions
of these, and thus we arrive at their com-
plete analysis.
  1. The different aerial fluids ought to be
first separated and  estimated.  For  this
purpose, a retort should  be filled  two-
thirds with the water, and connected with
ajar full of mercury, standing over a mer-
curial trough.  Let the  water be made to
boil for a quarter  of  an hour.  The aerial
fluids will pass over into the jar. When the
apparatus is  cool, the quantity of  air ex-
pelled from the water may be determined
either by bringing the mercury within and
without the jar to a level; or if this cannot
be done, by reducing the air to the proper
density by calculation.  The air of  the re-
tort ought  to be carefully subtracted,  and
the jar  should be divided into cubic inches
and tenths.
   The  only  gaseous bodies contained in
water are,  common air,  oxygen gas, nitro-
gen gas, carbonic acid,  sulphuretted hy-
drogen gas, and sulphurous acid. The last
two never exist  in water  together.  The
presence of either of them must be ascer-
tained  previously  by the application of the
proper tests. If sulphuretted hydrogen gas
be present, it will be mixed  with  the  air
contained in the glass jar, and must be se-
parated before this air be examined.   For
this purpose the jar must be removed into
a tub of warm water,  and nitric acid  in-
troduced,  which will absorb the sulphu-
retted hydrogen.  The residuum is  then to
be again put into a mercurial jar and exa-
mined.
   If the water contain sulphurous acid, this
previous step is not necessary.  Introduce
into the air a solution of pure potash, and
agitate  the  whole gently.   The carbonic
 acid and sulphurous  acid gas will  be ab-
 sorbed, and leave the  other  gases.  The
 bulk of this residuum, subtracted from the
 bulk of the whole,  will give the bulk of
 the carbonic acid and sulphurous acid ab-
 sorbed.
   Evaporate the potash slowly, almost to
 dryness, and leave it exposed to the at-
 mosphere. Sulphate of potash will be form-
 ed, which may be separated by dissolving
 the carbonate of potash by means of diluted 
                 WAT

muriatic acid,  and filtering  the solution.
100 grains of sulphate  of potash indicate
36.4 grains of sulphurous acid, or 53.66
cubic inches of that acid in the state of gas.
The bulk of sulphurous acid gas ascertain-
ed  by this method, subtracted from  the
bulk  of the  gas absorbed by the potash,
gives the bulk of the carbonic acid gas.
Now  100 cubic inches of carbonic acid, at
the temperature of 60° and barometer 30
inches, weigh 466 grains. Hence it is easy
to ascertain its weight.
  The gas remaining may be examined by
the common  eudiometrical processes.
  When a water contains sulphuretted hy-
drogen gas,  the bulk of this  gas is to be
ascertained in the  following manner:  Fill
three-fourths ofa jar with the water to be
examined, and invert it in a water trough,
and introduce a little nitrous gas.  This
gas, mixing  with the air in the upper part
of the  jar, will form nitrous acid, which
will render the water turbid, by decompo-
sing the sulphuretted hydrogen and preci-
pitating sulphur.  Continue to add' nitrous
gosatintervals as long as red fumesappear,
then turn up the jar and blow out the air. If
the hepatic smell continue, repeat this pro-
cess.  The sulphur precipitated indicates
the proportion of hepatic gas in the water;
one grain  of sulphur indicating the pre-
sence of nearly 3 cubic inches of this gas.
  2. After having  estimated  the gaseous
bodies, the next step is to ascertain the
proportion of the earthy carbonates.   For
this purpose it is necessary to deprive the
water of its  sulphuretted hydrogen, if it
contain any.  This may be done, either by
exposing it to the air for a  considerable
time, or treating it with litharge.  A suffi-
cient quantity of the water, thus purified
if necessary, is to be boiled for a quarter
of  an hour,  and filtered when cool.  The
earthy carbonates remain on the filter.
  The  precipitate  thus obtained may be
carbonate of lime, of magnesia, of iron,  of
alumina, or even sulphate of lime.  Let us
suppose allof these substances to be present
together.  Treat the mixture with diluted
muriatic acid, which will dissolve the whole
except the alumina and sulphate of lime.
Dry this residuum in a red heat, and note
the weight.  Then boil it in carbonate of
soda, saturate the soda with muriatic acid,
and boil the mixture for half an hour. Car-
bonate  of lime and alumina precipitate.
Dry this precipitate and  treat it with ace-
tic acid.  The lime will be dissolved, and
the alumina  will remain.  Dry it and weigh
it.  Its weight, subtracted from the original
weight, gives the proportion of sulphate of
lime.
   The  muriatic solution  contains  lime,
magnesia, and iron. Add ammonia as long
 as a  reddish precipitate appears. The iron
 and  part of  the magnesia are thus separa-
              WAT

ted.   Drv the precipitate, and expose it to
the air  for  some time in a heat of 200 ;
then treat it with acetic acid to dissolve the
magnesia; which solution is to be added to
the muriatic solution.  The iron is to be
redissolved  in muriatic acid, precipitated
by an alkaline carbonate.dried and weighed.
  Add sulphuric acid to  the muriatic solu.
tion as long as any precipitate appears; then
heat the solution  and concentrate.   Heat
the sulphate of lime thus obtained to red-
ness,  and weigh it.  100 grains  of it are
eqUivalentto 74.7 of carbonate of lime dried.
Precipitate  the magnesia hy means of car-
bonate of soda. Dry it and weigh  it. But as
part remains in solution, evaporate to dry.
ness,  and wash the residuum with a suffi-
cient quantity of distilled water, to dissolve
the muriate of soda and sulphate of lime,
if any be still present.   What remains be-
hind is carbonate of magnesia.  Weigh it,
and add its  weight to the former. The sul-
phate of lime,  if any, must also  be sepa-
rated and weighed.
  3. We have next to ascertain the propor-
tion of mineral acids or alkalis,  if any be
present uncombined. The acids which may
be  present,  omitting the gaseous, are the
sulphuric, muriatic, and  boracic.
  The proportion  of sulphuric acid is ea-
sily determined. Saturate  it with barytes-
water,  and  ignite  the  precipitate.   100
grains of sulphate of barytes thus formed
indicate 34.0 of real sulphuric acid.
  Saturate  the muriatic  acid with barytes-
water and then precipitate fche barytes by
sulphuric acid.  100 parts of the ignited
precipitate  are equivalent to 23.73 grains
of* real muriatic acid.
   Precipitate the boracic acid by means of
acetate of lead.  Decompose the  borate of
lead by boiling it in sulphuric acid.   Eva-
porate to dryness.  Dissolve the boracic
acid in alcohol, and evaporate the solution;
the acid left behind  may be weighed.
   To estimate the proportion of alkaline
carbonate present in a water containing it,
saturate it  with sulphuric acid,  and note
the weight of real  acid necessary.   Now
100 grains  of real sulphuric acid saturate
120.0 potash, and 80.0 soda.
   4.  The alkalidt sulphates may be esti-
mated by precipitating their acid by means
of nitrate  of barytes, having previously
freed the water from all other sulphates;
for 14.75 grains of ignited sulphate of ba-
rytes indicate 9.0  grains of dried sulphate
of soda; while 14.75 sulphate of barytes in-
dicate 11 of dry sulphate of potash.
   Sulphate  of lime  is easily estimated by
evaporating the liquid containing it  to a
few ounces (having previously  saturated
the earthy carbonates with nitric acid), and
precipitating the sulphate of lime by means
of weak alcohol.  It may then be dried an.'i
weighed. 
WAT                              WAT
  Tke quantity of  alum may be estimated
bv precipitating the alumina by  carbonate
of lime or of magnesia (if no lime be pre-
sent in the  liquid).  Eleven  grains of the
alumina, heated to incandescence, indicate
100 of crystallized alum, or 55 of  dried
salt.
  Sulphate of magnesia may be estimated,
provided no other sulphate be present, by
precipitating the acid by means of a bary-
tic salt, as 14.75 parts  of ignited sulphate
of barytes indicate 7.46 of sulphate of mag-
nesia.  If sulphate of  lime, and no other
sulphate, accompany it, this  may be de-
composed, and the  lime precipitated by
carbonate of magnesia.  The weight of the
lime thus obtained, enables  us to ascertain
the quantity of sulphate of  lime contained
in the water.  The whole of the sulphuric
acid is then to be precipitated by barytes.
This gives the quantity of sulphuric acid;
and subtracting  the  portion  which  be-
longs to the sulphate of lime, there remains
that which was combined  with the mag-
nesia,  from which  the sulphate of mag-
nesia may be easily estimated.
   If sulphate of soda be present, no earthy
nitrate or muriate can exist.  Therefore,
if no other earthy sulphate  be present, the
magnesia may be precipitated by soda, dri-
ed and weighed; 2.46  grains of which in-
 dicate 7.46 grains  of dried sulphate of
 magnesia.  The  same  process  succeeds
 when sulphate of lime accompanies tliese
 two sulphates; only  in this case the preci-
 pitate, which consists both of lime and
 magnesia, is to be dissolved in sulphuric
 acid, evaporated  to dryness, and treated
 with twice its weight  of cold water, which
 dissolves  the sulphate of  magnesia, and
 leaves the other salt.   Let the sulphate of
 magnesia be  evaporated to dryness, ex-
 posed to a heat of 400°, and weighed. The
 same process succeeds, if alum be present
 instead of sulphate of lime.  The precipi-
 tate in this case, previously dried, is to be
 treated with acetic acid, which dissolves
 the magnesia, and leaves the alumina. The
 magnesia may be again precipitated, dried
 and weighed.  If sulphate of iron be pre-
 sent, it may be separated by exposing the
 water to the air for some days, and mixing
 with it a portion  of alumina.  Both the ox-
 ide of iron, and the sulphate  of alumina,
 thus formed, precipitate in the state of an
 insoluble powder.  The sulphate of mag-
 nesia may then be estimated by the rules
 above given.
    Sulphate of iron may be estimated by
 precipitating the iron by means of prussic
 alkali, having previously  determined the
 weight of the precipitate produced by the
 prussiate in  a solution of a given weight of
  sulphate of iron  in water.  If  muriate of
  iron be also  present, which is a very rare
  Case, it may be  separated  by evaporating
the water to dryness, and treating the re-.
siduum with alcohol, which  dissolves the
muriate, and leaves the sulphate.
  5. If muriate of potash or of soda, with-
out any other salt, exist in water, we have
only to decompose them by nitrate of sil-
ver, and  dry  the precipitate; for 18.2 of
muriate of silver indicate 9.5 of muriate of
potash; and 18.2 of muriate of silver  indi-
cate 7-5 of common salt.
  The same process is to be followed,  if
the alkaline carbonates be  present; only
these carbonates must be  previously satu-
rated  with  sulphuric acid;  and we  must
precipitate the muriatic acid by  means  of
sulphate of silver instead  of nitrate. The
presence  of sulphate of soda does not in-
jure the success of this process.
   If muriate of ammonia accompany either
of the fixed alkaline sulphates, without the
presence  of any other salt, decompose the
sal ammoniac by  barytes-water, expel the
ammonia by boiling, precipitate the barytes
by diluted sulphuric acid, and saturate the
muriatic acid with soda   The sulphate of
barytes thus  precipitated,  indicates the
quantity  of muriate of  ammonia;  14.75
grains of sulphate indicating 670 grains
of this salt.  If any sulphate be present in
the solution, they ought to  be previously
 separated.
  .If common salt be accompanied by mu-
riate of lime, muriate of magnesia, muriate
 of alumina, or muriate of iron,  or  by  all
 these  together, without any other salt, the
earths may be precipitated by barytes-wa-
 ter, and redissolved in muriatic acid. They
 are then to be separated  from each other
 by the rules formerly laid down,  and their
 weight,  being determined,  indicates the
 quantity of every particular earthy muriate
 cortained in  the water.   For 50 grains of
 lime indicate 100 of dried muriate of lime;
 30 grains of magnesia indicate 100  of the
 muriate  of that  earth; and 21 8 grains of
 alumina  indicate  100 ofthe muriate of alu-
 mina. The barytes is to be separated from
. the  solution by  sulphuric acid, and the
 muriatic acid expelled by heat,  or satura-
 ted with soda; the common salt may then
 be ascertained by evaporation; subtracting
 in the last case the proportion of common
 salt indicated by the  known quantity of
 muriatic acid, from which  the earths had
 been  separated.
    When sulphates and muriates exist to-
 gether, they ought to be separated either
 by precipitating the sulphates by means of
 alcohol,  or by evaporating the whole to
 dryness, and dissolving the earthy muriates
 in alcthol.  The salts thus separated may
 be estimated by the rules already laid
 down.
    When alkaline and earthy muriates  and
 sulphate of lime occur together, the last is
 to be decomposed by means of muriate of 
WAT
WAT
barytes.   The  precipitate ascertains the
weight of sulphate of lime contained in the
water.  The  estimation is then to be con-
ducted as when nothing but muriates are
present; only from the muriate of lime, that
proportion of muriate  must be deducted,
which is known to  have been  formed by
the addition of the muriate of barytes.
  When  muriates of soda, magnesia, and
alumina  are  present;  together  with sul-
phates of lime and magnesia, the water to
be examined  ought to be divided into two
equal portions.  To the one portion add
carbonate of magnesia, till the whole of the
lime and alumina is precipitated.  Ascer-
tain the quantity of lime, which gives the
proportion of sulphate of lime.  Precipitate
the sulphuric acid by  muriate of barytes.
This  gives the  quantity contained  in the
sulphate  of magnesia and sulphate of lime;
subtracting this last portion, we have the
quantity  of sulphate of magnesia.
  From the second portion of water, pre-
cipitate all the  magnesia and alumina by
means of lime-water.  The weight of these
earths enables us to ascertain the weight of
muriate of magnesia and of alumina con-
tained in the water, subtracting that part
of the magnesia which existed in the state
of sulphate, as  indicated by the examina-
tion of the first portion of water.   After
this estimation, precipitate  the sulphuric
acid by barytes-water,  and the lime by car-
bonic  acid.  The  liquid, evaporated to
dryness,  leaves the  common salt.
  6. It now  only remains to  explain  the
method of ascertaining  the proportion of
the nitrates which may exist in waters.
  When  nitre accompanies  sulphates and
muriates without  any  other nitrates,  the
sulphates are to be  decomposed by acetate
of barytes, and the muriates by acetate of
silver.  The  water, after filtration, is to be
evaporated to dryness, and the residuum
treated with alcohol,  which dissolves  the
acetates, and leaves the nitre,  the quantity
of which may be easily  calculated.   If an
alkali be present, it ought to be  previously
saturated with  sulphuric or muriatic acid.
  If  nitre, common salt, nitrate of lime,
and muriate of lime or magnesia, be pre-
sent together, the water ought to be eva-
porated to dryness, and the dry mass treat-
ed  with alcohol, which takes up the earthy
salts  From the residuum,  redissolved in
water, the nitre may be separated, and cal-
culated as in the last case.   The alcoholic
solution  is to be evaporated to dryness, and
the residuum redissolved in water.  Let us
suppose  it to contain muriate of magnesia,
nitrate of lime, and muriate of lime.  Pre.
cipitate the muriatic acid by nitrate of sil-
ver, which gives the proportion of muriate
of  magnesia and of  lime.  Separate  the
magnesia by means of carbonate of lime,
and note its quantity. This gives the quan-
tity of muriate of magnesia; and subtract-
ing the muriatic acid contained in that salt
from the whole acid indicated by the pre-
cipitate of silver, we have the proportion
of muriate of lime.  Lastly,  saturate the
lime added to precipitate the magnesia
with  nitric acid.   Then  precipitate  the
whole  of the lime  by sulphuric acid;  and
subtracting from the whole of the sulphate
thus formed, that  portion formed  by the
carbonate of lime added, and by the lime
contained  in the  muriate, the residuum
gives us the lime contained in the original
nitrate; and 35 grains of lime form 100 of
dry nitrate of lime.
   * In the year 1807, Dr. Marcet advanced
some  new ideas on  the  art  of analyzing
mineral waters, in  an admirable  paper on
the water of the Dead Sea, inserted in the
Phil. Transactions.   " It is satisfactory to
observe," says this excellent chemist, "that
Dr. Murray  adopted, several years after-
wards, a  mode  of  proceeding  precisely
 similar, and indeed that he proposed, in a
 subsequent paper, a general formula for
 the analysis of mineral waters, in which
this.method is pointed out, as  likely to lead
to the most  accurate  results.   And this
 coincidence is the  more remarkable, as it
 would appear  from Dr. Murray not men-
 tioning my labours,  that they had not at
 that time come to  his knowledge."  Phil.
 Trans. 1819. part ii.
   The following table exhibits the  compo-
 sitions of the principal mineral waters, as
 well as that of the sea.  The reader will
 find in  the  Phil. Trans, for  1819, a very
 valuable dissertation on sea-water, by Dr.
 Marcet, of which a good abstract is given
 in the 2d volume of the Edin. Phil. Journal.
 This  philosopher  shows,  that in Baffin's-
 Bay, the Mediterranean Sea,  and the Tro-
 pical Seas, the temperature of the sea dimi-
 nishes with the depth, according to the ob-
 servations of Phipps, Ross, Parry,  Sabine,
 Saussure, Ellis, and  Peron; but that in the
 Arctic or Greenland Seas, the temperature
 of the sea increases with the  depth.  This
 singular result was  first obtained by Mr.
 Scoresby, in a series of well conducted ex-
 periments, and has been confirmed by the
 later observations  of Lieutenants Franklin
 and Beechy, and Mr. Fisher.* 
* TABLE of the Composition ofthe most celebrated Mineral Waters.																				1	
Names of the Spring!.	Grains of water.	C Oxy-geu.	ubic inches of gases. _ . , Sulph. ?arbo". hydro- Azote. nic acid. *en#			Soda. gr-	Lime. gr.	Magne- j Iron." sia. I gr- ; &•		Soda. gr-	l.ime. Magne-: Iron.l sia. 1 1 gr. gr. j gr. |			Soda. gr-	Lime. jMagne-; Pot- I sia. 1 ash. 1 gr- | gr- | gr-			Sili-' Alu-ca. :mina. gr- j gr.		Re- | sins. gr-	rero-pera-ture.
i rSelizer (■) % | Pyrmont (I) -■3 -{ Spa(l) - • - -"5. | Carlsbad (2) . - • ^ LKilbum (10) -	---- 8449 8950 8933 25320 138240	-- 43.5	13.068 19.6 9.8 50.0 84.0	36.0		5.22 1.85 38.5	78.3 4.3 1.85 12.5 2.4	6.32 9.8 4.35 1.25	0.70 0.70 0.1 1-4 0.3 1-4	66.75 18.2	8.38 13.0	5.44 91.0		13.74 1.7 0.21 32.5 6.0	0.6	2.8		2.25		6.0	cold cold cold 165° cold cold cold 143« cold
. rHarrowgaie (14) -ja -• J Moffat (4) - • 3g^ Aix-ia-Chapetle 0) - -3, *■ LEnghieii (5) - -rSedlitx . - -u | Cheltenham (6) ■3 4 Plombieres (20) $ | Dunblane (16) sp.gr. 1.00478 LPiteaithly(16)	103643 10.(643 8940 W160 58309 Ktf643 14600 7291 7291		8-0 19.0 1.0 10 0 13.06 18.5 : 7.0		7.0 4.0		18.5 15.25 21.4	5.5 5.89 1.35			33.3	0.5 5.8		615.5 3.6 6.21 2.4	3.0	9.1 8.0		_'	15.1		
			8.0 30.3 1.	3.0	13.0	36.	6.7 0.4 0.5 0.5	21.0 12.5	5.0 0.17	49.0 1.0 3.7 0.9	41.1 40.	1444	11.2	5.0 2.0 21. 12.7	20.8 20.2	36.5 12.5		1_ 1 1.12		---1	cold cold eold cold cold cold cold cold
>»a3 fTunbriilgc (3) « S •< Brighton (4) - -3 I LToplitz (7) -	103643 58309 22540	1.4	10.6 18.0		4.0	13.5	16.5		1.0 32.5	3.0 11.3 3.896	1.25 32.7			0.5 12.3 61.3	28.5	2ft 5 6.0					
JK rB»th(8) - - - • g a. 1 Buxton (9) ■ - -5^ Bristol (11) - - • 5*5 1 Matlock -tf § LMalvern (15) - - -	15360 58309 58309 58309 58309		3.4 30.3		3.0	5.33	1.6 10.5 13.5 1.6	0.93	0.004 .625		18 0 2.5 11.7 trace			6.6 1.5 4W 1.55		7.25		0.4	--		114° 82" 749 66° cold
Dead Sea (17) sp. gr. 1.211 Do. (18) sp. pr. 1.245 Do. (19) tp.gr. 1.2283	100 7291									25.6	.054			10.676 7.8 6.95 1 159.3	3.8 10.6 4.0 5.7	10.1 24.2 15.31 35.5	trace. t				
Mac- sss:? rSjsssar $£=&. cSSf $5** c8£w (ffi Dr. Marcet. (8) KtoJ^th. (») M. Gay-Lumc. (20) Vauquelin. t Dr. Wollaston.																					
1--- .																					
 
WAT
WAX
  • Water (Oxygenized), or deutoxide
of hydrogen.  This interesting compound
has been lately formed by M. Thenard, and
an account of it published in the tenth vo-
lume ofthe Annales de Chimie et Physique.
The deutoxide of barium being  dissolved
in water, and sulphuric acid  added, the
protoxide of barium or barytes falls down,
leaving the 6*xygen combined with the wa-
ter.  It contains, at 32 degrees Fahrenheit
when saturated, twice the quantity of oxy-
gen  of common water; that is  to  say, a
cubic inch absorbs 662  cubic inches =
224.46 gr. forming 476.98 grains, and ac-
quires  a  specific gravity of 1.453.   Hence
1.0  in  volume,  becomes apparently  1.3;
containing 1324 volumes of oxygen;  and
1 therefore  contains very nearly 1000 vo-
lumes.
  lf\ consequence of this great density,
when it is poured into common water, we
see it  fall down  through 'that liquid like a
sort of sirup, though it is very soluble in
it.  It  attacks the epidermis almost in-
stantly, and produces a prickling pain, the^
duration  of which varies, according to the
quantity  ofthe liquid applied to  the skin.
If this  quantity be too great, or if the li-
quid be renewed, the skin itself is attack-
ed and destroyed.   When applied to the
tongue, it whitens it also, thickens the sa-
liva, and  produces in the organs of taste a
sensation difficult to express, but one which
approaches to that  of tartar emetic.  Its
action  on oxide of silver is exceedingly vi-
olent.  Every drop of the liquid let fall on
the dry oxide, produces a real explosion;
and so much heat  is evolved,  that  if the
experiment be made in a dark  place, there
is a very  sensible disengagement of light.
Besides the oxide of silver,  there are se-
veral other oxides, which act with violence
on oxygenated water; for example the per-
oxide  of manganese, that of cobalt, the
oxides of lead,  platinum, gold,  iridium,
rhodium, palladium.  Several metals  in a
state  of  extreme  division,  occasion  the
same phenomenon; such  as silver, plati-
num, gold, osmium, iridium, rhodium, pal-
ladium.  In  all the preceding  cases, it is
always the  oxygen united to the  water,
which  is  disengaged, and  sometimes like-
wise that ofthe oxide; but in others, a por-
tion  of the  oxygen unites with the metal
itself.  This is the case when arsenic, mo-
lybdenum, tungsten, or  selenium is  em-
ployed.  These metals are often acidified
with the  production of light.
  The  acids render the oxygenated water
more stable.  Gold in a state  of extreme
division acts with great force on pure oxy-
genated water; yet it has no action on that
liquid, if it be mixed with a little sulphu-
ric acid.
  M. Thenard took pure oxygenated water,
and diluted it, so that it contained only 8
times its volume of oxygen. He passed 22
measures of it into a tube filled with mer-
cury.  He then introduced a  little fibrin,
quite white, and recently  extracted from
blood.  The  oxygen began instantly to be
disengaged from  the water; the mercury
in the tube sunk; at the end of six minutes
the water was  completely  disoxygenated;
for it no longer effervesced with oxide of
silver. Having then measured the gas dis-
engaged,  he found  it  176 measures = 8
-j- 22, that is to say, as  much as the liquid
contained.  This gas contained neither car-
bonic acid nor azote. It was pure oxygen.
The same fibrin placed in contact with new
portions of oxygenated water,  acted in the
same manner.
  Urea, albumen, liquid or solid, and gela-
tin, do not disengage oxygen from water,
even very much oxygenated.   But the  tis-
sue of the lungs, cut into thin slices,  and
well washed; that of the kidneys and  the
spleen, drive the oxygen out of the water,
with as much facility, at least, as fibrin does.
The skin and the veins  possess  the same
property, but in a weaker degree.  These
results are equally interesting  and myste-
rious.  For a valuable application of oxy-
genated water, see Paints.*
  * Wavellite.   Colour grayish-white.
Imitative and crystallized, in very oblique
four--sided prisms,  flatly bevelled on  the
extremities, or truncated on the  obtuse la-
teral edges.  Shining, pearly.  Fragments
wedge-shaped.   Translucent.  As hard as
fluor spar.   Brittle.  Sp. gr. 2.3 to 2.8. Its
constituents are, alumina 70, lime 1.4, wa-
ter 26.2.—Davy.  It is said to contain  also
a small quantity of fluoric acid.  It occurs
in veins along with fluor spar, quartz,
tin-stone,  and copper, pyrites in granite,
at St. Austle in Cornwall.  At Barnsta-
ble  in  Devonshire,  where   it  was  first
found by Dr. Wavell,  it  traverses slate-
clay,  in the form of small contemporane-
ous veins.   It has been  found  in rocks of
slate-clay, near Loch Humphrey, Dumbar-
tonshire.*     ,
  Wax is an oily concrete matter gathered
by bees from plants.  Proust says, that the
bloom on fruit is real wax; and  that it i«
wax spread over leaves,  which prevents
them from being wetted,  as on the  cab-
bage-leaf.  He likewise finds it in the fe-
cula  of some vegetables,  particularly in
that of the small house-leek,  in which it
abounds.  Huber, however, asserts, from
his observations, that the wax  in bee-hives
is an artificial production, made by  the
bees from honey; that they cannot procure
it, unless they have honey or sugar for the
purpose; and that raw sugar affords more
than honey.
  It was long considered as a  resin, from 
WAX                               WEL
some properties common to it with resins.
Like them, it furnishes an oil and an acid
by distillation, and is soluble in all oils; but
in several respects it differs sensibly I'rom
resins.  Like these, wax has not a strong
aromatic taste and smell, but a very weak
smell, and when pure, no taste.  With the
heat of boiling water,  no principles  are
distilled from  it; whereas, with that lieat,
some essential oil, or at least  a spiritus
rector, is obtained from every resin.  Far-
ther, wax is less soluble in alcohol. If wax
be distilled with a heat greater than that
of boiling water, it  may  be  decomposed,
but not so easily  as resins can.  By this
distillation a small quantity of water is firut
separated from the wax, and  then some
very volatile and very penetrating acid, ac-
companied by a small  quantity of a very
fluid and very odoriferous oil.  As the dis-
tillation advances, the acid becomes more
and  more  strong, and  the oil  more  and
more thick, till its consistence is such, that
it becomes solid in the receiver, and is then
called butter of wax.   When the distilla-
tion is finished, nothing remains but a small
quantity  of coal, which is  almost incom-
bustible.
  Wax cannot be kindled, unless it is pre-
viously heated and reduced into vapours;
in which respect it resembles fat oils. The
oil and butter of wax may by repeated dis-
tillations be attenuated  and rendered more
and  more  fluid, because some portion of
acid is" thereby separated from  these sub-
stances;  which effect is similar  to  what
happens in the distillation of other oils and
oily concretes: but this remarkable effect
attends the repeated distillation of oil and
butter of wax, that they become more and
more soluble in alcohol; and that they never
acquire greater consistence by evaporation
of their more  fluid parts.  Boerhaave kept
butter of wax in a glass vessel open, or
carelessly  closed,  during  twenty  years,
without acquiring a more solid consistence.
It may be remarked, that wax,  its butter,
and  its oil, differ entirely from essential
oils  and resins in all the above  mentioned
properties,  and that in  all these they per-
fectly resemble sweet oils.  Hence Macquer
concludes, that wax resembles resins only
in being an oil rendered concrete  by an
acid; but that it differs  essentially from
these in the kind of the oil, which in resins
is of the nature of essential oils, while in
wax and in other analogous oily concretions
(as butter of milk, butter of cocoa, fyt of
animals, spermaceti, and myrtle-wax) it is
of the nature of mild, unctuous oils, that
are not aromatic, and not volatile, and are
obtained from vegetables by expression.
  It  seems probable, that the acidifying
principle, or oxygen, and not an actual acid,
may be the leading cause of the solidity, or
   Vol..  II.
low fusibility of wax.  Wax is very useful,
especially as a better material than any
other for candles.
  Wax may be deprived of its natural yel-
low disagreeable colour,  and be perfectly
whitened by exposure to the united action
of air  and water, by which method the
colour of many substances may be destroy-
ed.
  The art of bleaching wax consists in in-
creasing its surface; for which  purpose it
must be melted with a degree of heat not
sufficient to alter its quality, in a caldron so
disposed,  that the melted wax may flow
gradually  through a pipe at the bottom of
the caldron into a large tub filled with wa-
ter, in which is fitted a large wooden cylin-
der, that turns continually round its axis,
and upon which the melted wax falls.  As
the surface of this cylinder is always moist-
ened with cold water, the wax falling upon
it does  not adhere to it,  but quickly  be-
comes solid and flat, and acquires the form
of ribbands.  The continual rotation of the
cylinder carries off these ribbands as fast
as they are  formed,  and distributes them
through the tub.   When all  the wax that
is to be whitened is thus formed, it is put
upon large frames covered with linen cloth,
which are supported about a foot and a half
above the ground, in a situation exposed to
the air, the dew, and the sun.  The thick-
ness of the  several ribbands, thus placed
upon the frames,  ought not to exceed an
inch and  a half,  and they  ought to be
moved from time to time, that they may
all be equally exposed to the action of the
air.  If the weather be favourable, the co-
lour will be changed in the space of some
days.  It is then to be re-melted and form-
ed into ribbands, and exposed to the action
of the air as before.  These operations are
to be repeated till the wax is rendered per-
fectly white, and  then it is  to be melted
into cakes, or formed into candles.
   •  Wax is composed, according to MM.
Gay-Lussac and Thenard, of
        Oxvgen,      5.544
         Hydrogen,   12.672
        Carbon,      81.784
                    100.000
See Cerin-.*
  Wax is employed for many purposes in
several arts.  It is also used in medicine as
a softening, emollient, and relaxing reme-
dy: but it is only used  externally, mixed
with other substances.
  Weld,  or  Woald   (reseda  luteola,
Linn.), is a plant cultivated in Kent, Here-
fordshire,  and many other  parts of this
kingdom.  The whole of the plant is used
for dyeing yellow; though some assert, that
the seeds only afford the colouring matter.
  Two sorts of weld are distinguished: the
                     44 
WEL                               WHI
bastard, or wild, which grows naturally in
the fields; and the cultivated, the stalks of
which are smaller, and not so high.   For
dyeing, the latter is preferred, it abound-
ing more in colouring matter.   The more
slender the stalk, the more it is valued.
   When the weld is ripe, it is pulled, dried,
and made into bundles, in which state it is
used.
   The yellow communicated  to wool by
weld has little permanency, if the wool be
not previously prepared by some mordant.
For this purpose alum and tartar are used,
by means of which this plant gives a very
pure yellow, which has the advantage of
being permanent.
   For  the boiling, which is conducted in
the common way, Hellot directs four ounces
of alum to every pound of wool, and only
one ounce of tartar: many dyers, however,
use half as much tartar as alum.  Tartar
renders the colour paler, but more lively.
   For the welding, that is, for the dyeing
with weld, the plant is boiled in  a fresh
bath, enclosing it in a bag of thin linen, and
keeping it from rising to the top by means
of a heavy wooden cross.  Some dyers boil
it  till it sinks to the bottom of the  copper,
and then let a cross down upon it: others,
When  it is boiled, take it out with a rake
and throw it away.
   Hellot directs five or six pounds of weld
for every pound of cloth; but dyers seldom
use so much, contenting themselves with
three or four pounds, or even much less.
   To  dye silk plain yellow, in general no
other ingredient than  weld is used.  The
silk ought  to be scoured in the proportion
of twenty pounds of soap to the hundred,
and afterward alumed and refreshed,  that
is, washed after the aluming.
   A bath is prepared with two pounds of
weld for each pound of silk, which after a
quarter of an hour's boiling is to be passed
through a sieve or cloth into a vat: when it
is of such  a temperature as the hand can
bear, the silk is put in, and turned till the
colour is become uniform: during this ope-
ration the weld is boiled a second  time in
fresh water; about half of the first bath is
taken out, and its place supplied by a fresh
decoction.   This fresh bath may be used a
little hotter than the former; too  great a
degree of heat, however, must be avoided,
that no  part of the colour already  fixed
may be dissolved; it is to be turned as be-
fore, and in the  mean time a quantity of
the ashes of wine-lees is to be dissolved in
a part of the second decoction; the silk is
to be taken out of the bath, that more or
less of this solution may be put in, accord-
ing to the shade required.  After it has
been turned a few times, a hank is wrung
with the pin,  that it may be seen whether
 the colour be sufficiently full, and have the
 proper gold cast: if it should not, a little
more ofthe alkaline solution is added, the
effect of which is to give the colour a gold
cast, and to render it deeper.   In this way
the,process  is to be continued,  until the
silk has attained the desired shade; the al-
kaline  solution  may also be added along
with the second decoction of the weld, al-
ways taking  care, that the bath is not too
hot.
  If we wish to produce yellows with more
of a gold or jonquille  colour, a quantity of
anotta proportioned to the shade required
most be added  to the  bath  along with the
alkali.
  A  water-colour, called  weld-yellow, is
much used by  paper  hanging manufactu-
rers.  This is the colouring matter of weld
precipitated with  an earthy base.  The fol-
lowing is given in the Philosophical Maga-
zine as a method of preparing it very fine:
—Into a copper vessel put  four pounds of
fine washed whiting and as much soft wa-
ter, and boil them together, stirring them
with a deal stick, till the whole forms a
smooth mixture: then add gradually twelve
ounces of powdered  alum, still  stirring,
till the effervescence ceases, and the whole
is well mixed.   Into  another copper put
any quantity of  weld, with the roots upper-
most, pour in soft water enough to cover
every part containing seed; let it boil, but
not more than  a quarter of an hour; take
out the weld, and set it to drain, and pass
the whole of the liquor through  flannel.
To the hot mixture of earth and water, add
as much of this decoction as will produce
a good colour, keep  it on the fire till it
boils, and then pour out into  a deal or
earthen vessel.  The next day the liquor
may be decanted, and the colour dried on
chalk.
  Welter's Tube.  See Laboratory.
  • Wernerite.  Foliated Scapolite*
  * Wheat Flour.   See Gluten and
Zimome.*
  Wheat.     See  Bread,  Gluten,
Starch.
  * Whet-Slate. Colour greenish-gray.
Massive.  Feebly glimmering.   Fracture
slaty in the  large;  splintery in the small.
Fragments tabular.   Translucent  on the
edges. Streak grayish-white.  Soft in a low
degree. Feels rather greasy. Sp. gr. 2.722.
It occurs in beds in primitive and transition
clay-slate.  It  is found at Seifersdorf near
Freyberg.  Very fine varieties are brought
from Turkey, called Honestones.  It is used
for sharpening  steel instruments.*
  Whey. The  fluid part of milk which re-
mains  after  the curd has  been separated.
See Milk.  It contains a saccharine mat-
ter,  some butter, and a  small  portion of
cheese.
  * Whiskey. Dilute Alcohol, which see,
and Distillation.*
  White Copper.  See TotenaG. 
                 WIN

  White, Sfanish, and White Leas.
See Ceruse.
  Whiting. Chalk cleared of its grosser
impurities, then ground in a mill, and made
up into small loaves, is sold under the name
of whiting.
  Wine.  Chemists give the name of wine
in general to all liquors that have become
spirituous by fermentation.  Thus cider,
beer, hydromel or mead, and other similar
liquors, are wines.
  The principles and theory of the fermen-
tation which produces  these  liquors are
essentially  the  same.  The more general
principles we have  explained  under the
article Fermentation.
  All those nutritive, vegetable, and animal
matters, which contain sugar ready formed,
are susceptible of the spirituous fermenta-
tion.  Thus wine may be made of all the
juices of plants, the sap of trees, the infu-
sions  and decoctions of farinaceous vege-
tables,, the  milk of frugivorous animals;
and lastly, it may be made of all ripe  suc-
culent fruits; but all these substances are
not equally proper to be changed into  a
good  and generous wine.
  As the production of alcohol is the result
of the spirituous fermentation, that wine
may be considered  as essentially the best,
which contains  most alcohol.  But of all
substances  susceptible of the  spirituous
fermentation, none is capable of being con-
verted  into so good wine, as the juice  of
the grapes of France, or of other countries
that are nearly in the same latitude, or  in
the same temperature.  The grapes of hot-
ter countries, and even those of the south-
ern provinces of France, do indeed furnish
wines, that have a more agreeable, that is
more of a saccharine taste; but these wines,
though they are sufficiently strong, are not
so spirituous as those of the provinces near
the middle of France: at least, from these
latter wines the  best vinegar and  brandy
are made.  As  an  example, therefore,  of
spirituous fermentation in general, we shall
describe the method of making wine from
the juice of the grapes of  France.
  This juice, when newly expressed, and
before  it  has begun  to ferment, is called
must, and in common language sweet wine.
It is turbid, has an agreeable and very sac-
charine taste. It is very laxative; and when
drank too freely, or by persons disposed to
diarrhoeas, it is apt to  occasion these dis-
orders.  Its consistence is somewhat less
fluid than that of  water,  and  it becomes
almost of a pitchy thickness when dried.
   When  the  must is  pressed from  the
grapes, and put into a proper vessel and
place, with a temperature between fifty-tive
and sixty degrees, very sensible effects are
produced in it, in a shorter or longer time
according to the nature of the liquor, and
the exposure of the place,  it then swells,
               WIN

and is so rarefied, that it frequently over-
flows  the vessel containing it, if this be
nearly full. An intestine motion is excited
among its parts, accompanied with a small
hissing noise and evident ebullition.  The
bubbles rise to the surface, and at the same
time is disengaged  a quantity of  carbonic
acid of such purity, and so subtle  and dan-
gerous, that it is capable of killing  instantly
men and animals  exposed to it in a place
where the air is not renewed.  The skins,
stones, and other grosser matters of the
grapes are buoyed  up by the  particles of
disengaged air that adhere to their surface,
are variously agitated, and are raised in
form of a scum or  soft and spongy crust,
that covers the whole liquor.  During the
fermentation  this crust is frequently raised,
and broken by the air disengaged  from the
liquor which  forces its way through it; af-
terward the  crust subsides, and  becomes
entire as before.
  These effects continue while the fermen-
tation is brisk,  and  at last gradually cease:
then the crust,  being no longer supported,
falls in pieces to the bottom of the liquor
At  this time, if we would have  a strong
and generous wine, all sensible fermenta-
tion must be stopped.   This is  done by
putting the  wine into close vessels, and
carrying these into a cellar or other  cool
place.
  After this  first  operation, an interval of
repose takes place, as is indicated by the
cessation  of  the sensible effects of the spi-
rituous fermentation; and thus enables us
to preserve a liquor no less agreeable in its
taste, than useful for its reviving and nutri-
tive qualities when  drank moderately.
  If we examine the wine produced by this
first fermentation, we shall find, that it dif-
fers entirely  and essentially from  the juice
of grapes before  fermentation.  Its sweet
and saccharine taste is changed  into one
that is  very different, though still agreea-
ble, and somewhat  spirituous and piquant.
It has not the laxative quality  of must, but
affects the head,  and occasions, as  is well
known, drunkenness.  Lastly, if it be dis-
tilled, it yields, instead of the insipid water
obtained from must by distillation with the
heat of boiling water, a  volatile, spiritu-
ous, and inflammable liquor called spirit of
wine, or  alcohol.   This  spirit  is conse-
quently a new being, produced by the kind
of fermentation called the vinous or spi-
rituous.   See Alcohol-
  When any liquor undergoes the spiritu-
ous fermentation, all its parts seem not to
ferment at the same time; otherwise the
fermentation would probably be very quick-
ly completed, and  the appearances would
be much more  striking: hence, in a liquor
much disposed to fermentation, this motion
is more quick and simultaneous than  in
another liquor  less disposed.  Experience 
WIS
NIX
has shown, that a wine, the fermentation of
which is very  slow and tedious, is never
good or veiy  spirituous; and therefore,
when the weather is too cold,  the fermen-
tation is usually accelerated by heating the
place in which the wine is made.  A pro-
posal has been made by a person very in-
telligent in economical affairs, to  apply  a
greater than  the usual heat to accelerate
the fermentation of the wine, in those years
in which grapes have not been sufficiently
ripened, and when the juice  is not suffi-
ciently  disposed to fermentation.
   A too hasty and violent fermentation is
perhaps also  hurtful, from the dissipation
and loss of some of the spirit; but of this
we are  not certain. However, we may dis-
tinguish in the ordinary method of making
wines of grapes, two periods in the  fer-
mentation; the first of which  lasts during
the appearance of the sensible effects above
mentioned,  in which the greatest number
of fermentable particles ferment. After this
first effort of fermentation,  these effects
sensibly diminish,  and ought to be stopped,
for reasons hereafter to be mentioned. The
fermentative  motion  of the  liquors then
ceases. The heterogeneous parts, that were
suspended in the wines by this motion, and
render it muddy, are separated, and form
a sediment called the lees; after which the
wine becomes clear; but though the  opera-
tion is  then considered as finished, and the
fermentation apparently ceases, it does not
really cease; and it ought to be continued
in some degree,  if  we  would have good
 wine.
   In this new wine a part of the liquor pro-
 bably remains, that has not fermented, and
 which  afterward ferments, but so very slow-
 ly, that none  of the sensible effects pro-
 duced  in the  first fermentation are  here
 perceived. The fermentation therefore still
 continues in the wine, during a longer  or
 shorter time, although in an imperceptible
 manner;  and  this is the second period of
 the spirituous fermentation, which may be
 called  the imperceptible fermentation. We
 may easily perceive, that the effect  of this
 imperceptible fermentation  is the gradual
 increase ofthe quantity  of alcohol.   It has
 also another effect no less  advantageous,
 namely, the separation ofthe acid salt called
 tartar  from the wine.  This matter is there-
 fore a second sediment, that is formed  in
 the wine, and adheres to the sides of the
 containing vessels.  As the taste  of tar-
 tar is harsh and disagreeable,  it is evi-
 dent, that the wine, which by means of the
 insensible fermentation  has acquired more
 alcohol, and has  disengaged  itself of the
 greater part of its tartar, ought to he much
 better and more   agreeable;  and for this
 reason chiefly old wine  is universally pre-
 ferable to new wine.
    B ut insensible fermentation can only ripen
and meliorate the wine, if the sensible fer-
mentation have regularly proceeded, and
been stopped in due time.   We know cer-
tainly, that if a  sufficient time have not
beeJi allowed for the first period ofthe fer-
mentation,  the  unfermented matter that
remains, being in too large a quantity, will
then  ferment in the bottles, or close vts-
sels in which the wine is put, and will oc-
casion effects so much more sensible, as
the first fermentation shall have been sooner
interrupted: hence these wines are always
turbid, emit bubbles, and sometimes break
the bottles, from the large quantity of air
disengaged during the fermentation.
   We have an instance of these effects in
the wine of Champagne, and in others of
the same kind.   The sensible fermentation
of tliese wines is interrupted, or rather sup-
 pressed, that they may have this sparkling
 quality.  It is well known, that these wines
 make the corks fly out of the  bottles; that
 they sparkle and froth when they are pour-
 ed into glasses; and lastly, that they have
 a taste much more lively and more piquant
 than wines  that do not  sparkle: but this
 sparkling quality,  and all  the  effects de-
 pending on  it, are only caused by a  consi-
 derable quantity of carbonic acid gas, which
 is disengaged during the confined ferment-
 ation, that the wine has undergone in close
 vessels. This air not having an opportunity
 of escaping, and of being dissipated as fast
 as it is. disengaged, and being interposed
 betwixt all the parts ofthe wine, combines
 in some measure with them, and  adheres
 in the  same manner as it does to certain
 mineral waters, in  which it produces near-
 ly the  same effects.  When this air  is en-
 tirely disengaged from these  wines, they
 no longer sparkle, they lose their piquancy
 of taste, become mild, and even almost in-
 sipid.
   Such are the qualities that wine acquires
 in time, when its first  fermentation has not
 continued sufficiently  long.  These quali-
 ties are given purposely to certain kinds
 of wine, to indulge taste  or  caprice; but
 such wines are supposed to  be unfit for
 daily use.  Wines  for daily use ought to
 have undergone so completely the sensible
 fermentation, that the succeeding fermen-
 tation shall be insensible, or at least exceed-
 ingly little perceived.   Wine, in which the
 first fermentation has been too far advanced,
  is liable to worse inconveniences than that
  in which the  first  fermentation has been
 too  quickly suppressed; for every fermen-
  table liquor is from its nature in a continual
  intestine  motion, more or less strong  ac-
  cording to circumstances,  from the first
 instant of the spirituous  fermentation  till
 it is completely purified: hence from the
 time of the completion of the spirituous
 fermentation, or even  before, the wine be-
 gins to undergo the  acid or  acetous fer- 
WIN
WIN
mentation.  This acid fermentation is very  acescency of wine, we may conclude, that
slow and insensible, when the wine is in-  when this accident  happens, it cannot by
eluded in very close vessels, and in a  cool  any good method be remedied, and that
place; but it gradually advances,  so  that  nothing remains to be done with sour wine
in a certain time the wine, instead of be-  but to sell it to vinegar-makers, as all ho-
ing improved,  becomes at last sour.  This  nest wine-merchants do.
evil cannot be  remedied; because the fer-    * As the  wjms* of  the  grape contains a
mentation may advance,  but  cannot be re-  notable proportion of tartar, which our cur-
verted,                                   rant and gooseberry juices do not, I have
   Wine-merchants, therefore, when their  been accustomed, for many  years, to re-
wines become sour, can only conceal or ab-  commend in my lectures, the addition  of
sorb this acidity by certain substances, as  a small portion of that salt to our must, to
by alkalis and absorbent earths.  But these  make it  ferment into a more genuine wine.
substances give to wine a dark greenish  Dr.  M'Culloch has  lately prescribed the
colour, and a taste which, though not acid,  same addition in his popular treatise  on
is somewhat disagreeable.  Besides, cal-  the  art of making wine.
careous earths accelerate considerably the     The following is  Mr. Brande's valuable
total destruction and  putrefaction of the  table of the quantity of spirit in different
wine.  Oxides of lead, having the property  kinds of wine:—
of forming with the acid of vinegar a salt                              Proportion of
of an  agreeable saccharine taste, which                              spirit per cent
does not alter the colour of the wine,  and                              by measure.
which besides has the  advantage  of  stop-   1.  Lissa.........26.47
ping fermentation and putrefaction, might        Ditto,   -  -.  -  -   -   -•-   -  24.35
be very well  employed to remedy the aci-                         Average,    25.41
dity of wine,  if lead and  all its prepara-   2.  Raisin wine,......26.40
tions were not pernicious to health, as they       ' Ditto,........25.77
occasion most terrible  colics,  and  even    *   Ditto,........23.20
death, when taken internally.  We cannot                        Average,     25.12
believe  that any  wine-merchant, knowing   3.  Marsala,.......26.3
the evil consequences of lead, should,  for       Ditto,........25.5
the sake of gain, employ it for the purpose                        Average,     25.9
mentioned; but if there  be any such per-   4.  Madeira,.......24.42
sons, they must be considered as the poi-       Ditto,........23.93
soners and murderers  of the public.  At       Ditto  (Sircial)   -   -   -  -  -   21.40
Alicant, where very sveet wines are made,       Ditto,........19.24
it is the practice to mix a little lime with                        Average,    22.27
the  grapes before they are pressed.   This,   5. Currant wine,......20.55
 however, can only neutralize the acid al-   6. Sherry,  -  -   -.....19.81
 ready existing in the grape.                    Ditto,  -  -   -.....19.83
   If wine contain litharge, or any  other       Ditto,  -.......18.79
 oxide of lead, it may  be  discovered by       Ditto,........18.25
 evaporating some pints of  it to  dryness,                         Average,    19.17
 and melting the residuum in a crucible, at   7. TenerifFe,.......19.79
 the bottom of which a small button of lead   8. Colares,  -  -   -.....19.75
 may be found after the fusiop: but an easier   9. Lachryma Christi,   ...  -  19.70
 and more expeditious proof is by pouring   10. Constantia, white,   ...  -  19.75
 into the wine  some liquid  sulphuret.  If  11.   Ditto red,......18.92
 the precipitate occasioned by this addition   12. Lisbon,......-  -  18.94
 of the sulphuret be white, or only coloured   13. Malaga, (1666)  -  -  -  - -  18.94
 by the wine, we may know, that no lead is   14. Bucellas,.......18.49
 contained in it: but if the  precipitate be   15. Red Madeira,  ------  22.30
 dark coloured, brown, or blackish, we may       Ditto,  -  -   -.....18.40
 conclude* that it contains lead or iron.                            Average,    20.35
   The only substances that cannot absorb   16. Cape Muschat,.....18.25
  or destroy, but cover and render support-  17. Cape Madeira,   -----  22.94
  able the sharpness of wine, without  any      Ditto,........20.50
  inconvenience, are sugar, honey, and other      Ditto,   --......18.11
  saccharine alimentary  matters;  but they                        Average,    20.51
  can succeed  only when the wine is very  18. Grape wine,   -   -)  -  -  -  -  18.11
  little acid, and when an  exceeding small  19. Calcavella,.......19.20
  quantity only of these substances is suffi-       Ditto,........18.10
  cient to produce the desired effect;  other-                        Average,    18.65
  wise the wine would have a sweetish, tart,  20. Vidonia,........19.25
  and not agreeable taste.                   21. Alba Flora,.......17.26
    From what is here said concerning the  22. Malaga,.....-  .   -  17.26 
WOA
WOA
                             Proportion of grows  wild in some parts of France, anil
                             spirit per cent  on the  coasts of the Baltic Sea; the  wild
                             by measure.   woad, and that which is cultivated for the
 23.  White Hermitage,.....17.43  use of the dyers, appear to be the same
 24.  Rousillon,.......19.00  species of plant.
       Ditto........17.26    The  preparation of woad for dyeing,  as
                       Average,    1813  practised in France, is minutely described
 25.  Claret»........17.11  by Astruc, in his Memoirs for a Natural
     Ditto    ........16.32  History of Languedoc—The  plant  puts
     Ditto    ........14.08  forth at first five or six upright leaves about
     Ditto    ........  12.91  a foot  long  and  six  inches broad;  when
                       Average,    15.10  these hang downwards, and turn  yellow,
 26.  Malmsey Madeira,   ....  16.40  they are fit for gathering;  five crops are
 27.  Lunel,.........15.52  gathered in one year.   The leaves are car-
 28  Sheraaz,........15.52  ried directly to a mill, much resembling the
 29.  Syracuse,........  15.28  oil or tan-mills, and ground into a smooth
 30.  Sauterne,........14.22  paste.  If this process were deferred for
 31. Burgundy,......'  .  16.60  some time, they would putrefy, and send
       Ditto.....-•■-..  15.22  forth an insupportable stench.   The paste
       Ditto   .  .  •......14.53  is laid  in heaps pressed close and smooth,
       Ditto.......'  -  11.95  and the blackish crust, which forms on the
                       Average,    14.57  outside, reunited if it happen to crack:  if
 32. Hock, .  •.......   .  14.37  this were neglected, little worms would be
    Ditto........   .  13.00  produced in the cracks, and the woad would
    Ditto (old in cask)   ....   8.88  lose part of its  strength.   After lying for
                       Average,    12.08  fifteen  days,  the heaps are opened, the
 33. Nice,.........14.63  crust rubbed and mixed  with the inside,
 34. Barsac,........13.86  and the  matter  formed  into  oval balls,
 35. Tent,.........13.30  which are pressed close and solid in wood-
 36. Champagne, (still)   ....  13.80  en moulds.  These are dried upon hurdles:
       Ditto   (sparkling)  .   .   .  12.80  in the sun they turn black on the outside,
       Ditto    (red).....12.56  in a close place yellowish, especially if the
       Ditto    (ditto).....11.30  weather be rainy. The dealers in this corn-
                       Average,    12.61  modity prefer the first, though it is said
 37. Red  Hermitage,.....12.32  the workmen  find  no considerable diffe-
 38. Vin de Grave,......13.94  rence between  the  two.  The good balls
         Ditto      ......12.80  are distinguished by their being weighty,
                       Average,    13.37  of a pretty agreeable smell, and, when rub-
 39. Frontignac,.......  1279  bed, of a violet colour within.
 40. Cote Rotie........12.32    For the use of the dyer, these balls re-
41. Gooseberry wine,.....'  11.84  quire a farther preparation; they are beaten
42., Orange wine,—average of six sam-       with wooden mallets, on a brick or stone
     pies made  by a London manu-       floor, into a gross powder, which is heaped
     facturer,.......11.26  up in the middle of the room to the height
43. Tokay,.........9.88  of  four feet, a space being left  for passing
44. Elder wine,.......9.87  round the sides.  The powder  moistened
45. Cyder, highest average,  .   .   .   9.87  with water ferments, grows hot, and throws
    Ditto, lowest ditto.....5.21  out a thick  fetid fume.   It is shovelled
46. Perry, average of four samples,   7.26  backward and forward, and moistened ev-
47. Mead,.........7.32  ery day for twelve days; after which it is
48. Ale (Burton).......8.88  stirred  less frequently, without watering;
    Ditto (F.dinburgh).....6.20  and at  length made into a heap for  the
    Ditto (Dorchester)   ....   5.56  dyer.
                       Average,     6.87   The  powder  thus prepared  gives only
49. Brown stout,......6.80  brownish tinctures  of different shades to
50. London Porter (average)   .   .   4.20  water, to alcohol, to ammonia, and to fixed
51. Ditto small beer, (ditto) .   .   .   1.28  alkaline lixivia; rubbed on paper, it com-
52. Brandy,........53.39  municates a green stain.  On diluting the
53. Rum,  ....'..-..  53.68  powder with boiling water, and, after stand-
54. Gin,..........  51.60  ing for some hours in a close vessel, adding
 55. Scotch Whiskey,  .....  54.32  about one-twentieth  its weight of lime new-
 56. Irish ditto........53.90  ly slaved,  digesting in a gentle warmth,
                                          and stirring the whole together every three
   * Witherite.  Carbonate  of  barytes.  or four hours, a new fermentation begins;
 See Heavy-Spar.*                        a blue froth rises to the surface, and the
   Woad, Isatis, Glastum, is a plant which  liquor, though it appears itself of a reddish 
YTT
YTT
colour, dyes woollen  of a green;  which,
like the green from indigo, changes in the
air to a blue.   This  is  one of the  nicest
processes  in the art of dyeing, and does
not well succeed in the way of a small ex-
periment.
  * Wo dan i um.  A  new  metal recently
discovered by  Lampadius in the mineral
called  Hroodan pyrites.  This metal has a
bronze-yellow colour similar to that of co-
balt glance; and its sp. gr. is 11.470. It is
malleable; its fracture is hackly; it has the
hardness of fluor spar; and is  strongly at-
tracted by the magnet.
  It is not tarnished by exposure to the
atmosphere at the common temperature;
but when heated it is converted into a black
oxide.
   The solution of this metal in acids is co-
lourless; or at least has only a slight wine-
yellow tinge.  Its hydrated carbonate is also
white. The hydrate,  precipitated by caus-
tic ammonia, is indigo-blue.
   Neither the alkaline phosphates nor ar-
senates  occasion  any  precipitate,  when
dropped into  a saturated solution of this
metal in an acid; nor is any precipitate pro-
duced by the infusion of galls.  A plate of
zinc throws down a black metallic powder
from the solution of this metal in muriatic
acid.   Prussiate of potash throws down a
pearl-gray precipitate.
  Nitric acid dissolves with facility both
the metal and its oxide, and the  solution
yields   colourless  needle-form  crystals,
which  readily dissolve in water.— Gilbert's
Annalen der Physik, September 1818.*
  *  Woodan  Pyrites.   See Ores  op
Wodanium.*
  * Wood (Opal).  See Opal.*
  Wood (Rock). The ligniform asbestus.
  *  Wood-stone. A sub-species of horn-
stone.*
  *  Wood-tin.   See  Ores of Tin.*
  Wootz. The metal extracted from some
kind of iron  ore in the East Indies, appa-
rently of good quality.  It  contains more
carbon than steel, and less  than cast iron,
but from want of skill in the management
is far from homogeneous.—Phil. Trans.
   * Wort.   See  Beer, Distillation,
and Fermentation.*
   * Wolfram.   See Ores of Tungs-
• \TANOLITE.   Axinite.*
  X  * Yeast.   See Fermentation,
and Bread.*
  * Yellow  Earth.  Colour ochre-yel-
low.  Massive.  Dull.  Fracture  slaty or
earthy. Streak somewhat shining. Opaque.
Soils slightly.  Soft.  Easily frangible.  Ad-
heres to the tongue.  Feels rather greasy.
Sp. grav. 2.24.  Before the blow-pipe it is
converted into a black and shining enamel.
Its  constituents are, silica 92, alumina 2,
lime 3, iron 3.—Merat-Guillot.  It is found
at Wehraw in  Upper Lusatia, where it is
associated  with clay and clay-ironstone.
When burnt, it is  sold by the Dutch as a
pigment, under the name of English red.
It was used as a yellow paint by the  an-
cients.*
  * Yenite.   Lievrite.*
  Yttria.  This  is a new  earth, disco-
vered in 1794 by Prof. Gadolin in a stone
from Ytterby  in  Sweden.  See  Gadoli-
nite.                               .
  It may be obtained most readily by fusing
the  gadolinite with two parts of caustic
potash, washing the mass with boiling wa-
ter, and filtering the liquor, which  is of a
fine green.  This  liquor is to be evapora-
ted, till no more oxide of manganese falls
down  from it in  a black powder; after
which the liquid is to be  saturated with
nitric acid. At the same time digest  the
sediment, that was not dissolved, in very
dilute nitric acid,  which will dissolve  the
earth with much heat, leaving the silex,
and  the highly oxided iron, undissolved.
Mix the two liquors, evaporate them to
dryness, redissolve, and filter,  which will
separate any silex or oxide of iron that may
have been left.  A few drops of a solution
of carbonate  of potash  will separate  any
lime that may be present, and a cautious
addition of hydrosulphuret of potash will
throw down the oxide of manganese that
may have been left; but if too much  be
employed, it will  throw down  the  yttria
likewise.  Lastly, the yttria is to be preci-
pitated by pure ammonia, well washed, and
dried.
  Yttria is perfectly white, when not con-
taminated with  oxide of manganese, from
which it is not easily freed.  Its specific
gravity is 4.842.  It has neither taste  nor
smell.  It is infusible alone; but with borax
melts into a transparent  glass,  or opaque
white, if the borax were  in excess.  It is
insoluble in water, and in caustic fixed al-
kalis; but it dissolves in carbonate of  am-
monia, though it requires five or six times
as much as glucine.  It is soluble in most
of the acids.  The oxalic acid, or oxalate
of ammonia, forms precipitates in its solu-
tions perfectly resembling the muriate of
silver.   Prussiate of potash, crystallized
and redissolved in water, throws it down
in white grains; phosphate of soda, in white
gelatinous  flakes; infusion of galls,  in
brown flocks. 
ZEO
ZEO
  Some chemists are inclined to consider
yttria rather as a metallic than as an earthy
substance, their reasons are its specific gra-
vity, its forming coloured salts, and its pro-
perty of oxygenizing muriatic acid after it
has undergone a long calcination—Crell's
Chem.  Ann.—Scherer's Journ.—Annates de
Chimie.
  * When yttria is treated with  potassium
in the  same manner as the other earths,
similar results are obtained; the  potassium
becomes potash, and the earth  gains ap-
pearances of  metallization, so  that  it is
scarcely to be doubted, says Sir H. Davy,
that yttria consists of inflammable matter,
metallic in its nature, combined with oxy-
gen.  According to Klaproth, 55  parts of
yttria  combine with 18  parts of carbonic
acid; consequently, if it  be  supposed that
the  carbonate of yttria consists of  one
prime proportion of earth and one of acid,
its prime  equivalent will be 8.403; and that
of its  metallic basis probably  7.4.  The
salts of yttria have the  following general
characters.—
  1. Many of them are insoluble in water.
  2. Precipitates are occasioned in those
which dissolve, by phosphate of soda, car-
bonate of soda, oxalate  of ammonia, tar-
trate of potash, and  ferroprussiate  of pot-
ash.
  3. If we except the sweet-tasted  soluble
sulphate ^of yttria, the other salts  of this
earth resemble those with base of  lime in
their solubility.*
  * Yttro-Tantalite. An ore of Tan-
talum.*
  *  Yttro-Cerite.    Colours   reddish
and grayish-white, and violet-blue.  Mas-
sive, and in crusts.   Cleavage indistinct.
Opaque.  Yields  to  the  knife.  Scratches
fluor.  Sp. gr. 3.447.  Its constituents are,
oxide of cerium  13.15, yttria 14.6, lime
47.77,  fluoric acid  24.45.—-Berzelius.  It
has hitherto been found only at Finbo, near
Fahlun in Sweden, imbedded in quartz, or
incrusting pyrophysalite.*
Z
   ZAFFRE, or SAFFRE, is the residuum
    of cobalt, after the  sulphur, arsenic,
and other volatile  matters of this mineral
have been expelled by calcination.
  The zaffre that  is commonly sold,  and
which comes from Saxony, is a mixture of
oxide of cobalt with some vitrifiable earth.
It is of a gray colour, as all the oxides of
cobalt are before vitrification.
  * Zeolite.  The name ofa very exten-
sive mineral genus, containing the follow-
ing  species:—1. Dodecahedral zeolite or
leucite; 2. hexahedral zeolite or analcime;
3. rhomboidal zeolite, chabasite, or  chaba-
sie; 4. pyramidal zeolite, or cross stone; 5.
di-prismatic zeolite,or laumonite; 6.prisma-
tic zeolite, or mesotype, divided into three
sub-species,—fibrous zeolite, natrolite, and
mealy zeolite; 7.  prismatoidal  zeolite, or
stilbite,  comprehending foliated  zeolite,
and radiated zeolite; 8. axifrangible  zeo-
lite, or apophyllite.  The following belong
to this place:
  6. Prismatic zeolite or  mesotype.
  § 1. Fibrous  zeolite, of which there are
two kinds;  the  acicular  or needle  zeolite,
and common fibrous zeolite.
   a.  Acicular or  needle  zeolite, the meso-
type of  Hatty.  Colours grayish, yellowish
 or" reddish-white.   Massive, in distinct con-
 cretions, and crystallized   Primitive form,
 a prism of  91° 25'.  The following are se-
 condary figures:—An acicular rectangular
 four-sided  prism, very  flatly acuminated
 with four planes, set on the lateral planes;
 sometimes two of the acuminating planes
disappear, when there is formed an acute
bevelment, or the prism is sometimes trun-
cated on the edges.   Lateral planes longi-
tudinally  streaked.  Shining, inclining to
pearly.  Cleavage twofold.  Fracture small
grained  uneven.    Fragments  splintery.
Translucent.  Refracts double.  As hard
as apatite.  Brittle.   Sp. gr. 2.0 to 2.3.   It
intumesces before the blow-pipe, and forms
a jelly with acids.   It becomes elastic by
heating,  and retains this  property some
time after it has cooled.  The free extre-
mity of the crystal  with the acumination,
shows positive, the attached end, negative
electricity.    Its  constituents  are, silica
50.24, alumina 29.3, lime 9.46, water 10.—
 Vauquelin.   It occurs in secondary  trap
rocks, as in basalt, green-stone, and amyg-
daloid.  It  is found near the village of Old
Kilpatrick,   Dumbartonshire;  in Ayrshire
and Perthshire, always in trap rocks; in
Iceland and the Faroe Islands.
   b. Common fibrous zeolite.  Colour white.
Massive, in distinct concretions, and in ca-
pillary crystals. Glimmering, pearly. Frag-
ments splintery. Faintly translucent. Hard-
 ness  as  before.  Rather  brittle.  Sp. gr.
 2.16  to  2.2-  Chemical  characters and si-
 tuations as above.   Its constituents are, si-
 lica 49, alumina 27,  soda  17, water 9.5.—
 Smithson.
   § 2. Mealy zeolite.  Colour white, of va-
 rious shades. Massive, imitative, in a crust
 or in delicate fibrous concretions.  Feebly
 glimmering.    Fracture  coarse   earthy.
 Opaque.  The mass is soft, but the minute) 
ZER                                  ZIN
parts as hard as the  preceding.   Sectile.
Most easily frangible.  Does  not adhere
to the tongue.  Feels meagre.  Sometimes
so light as nearly to float on water.  It in-
tumesces, and gelatinizes as the preceding.
Its constituents are, silica 60, alumina 15.6,
lime 8, oxide of iron 1.8, loss, by exposure
to heat, 11.6.—Hisinger.  It occurs like the
others.  It is found near Tantallon-castlfc,
in East Lothian, and in the islands of Skye,
Mull, and Canna.
  7.  Prismatoidal zeolite, or stilbite. Of this
there are two sub-species; the foliated and
radiated.
  $1. Foliated zeolite, the stilbite of Hatty.
Colour white, of various shades.   Massive,
disseminated, imitative, in distinct granu-
lar concretions, and crystallized.   Primi-
tive form, a prism  of 99°  22'.  Secondary
forms are, a low oblique four-sided prism,
variously truncated; a low equiangular six-
sided prism;  and an eight-sided  prism,
from  truncation of  all the edges of the
four-sided  prism.   Lateral  planes  trans-
versely streaked.  Shining, pearly.  Cleav-
age single.  Fracture conchoidal.   Trans-
lucent.  Refracts single.  As hard as cal-
careous spar.   Brittle.  Sp. gr.  2. to 2.2.
It intumesces  and phosphoresces before
the blow-pipe, but does not form a  jelly
with acids. Its constituents are, silica 52.6,
alumina 17.5, lime 9, water  18.5.— Vuuque-
lin.  It occurs  principally  in secondary
amygdaloid, either  in  drusy  cavities,  or
in contemporaneous veins.  It is  also met
with in primitive and transition mountains.
Very beautiful specimens of the red foli-
ated  and radiated zeolites are  found at
Carbeth in Stirlingshire, and at Loch Hum-
phrey in Dumbartonshire; also in the  se-
condary trap rocks of the Hebrides, as of
Skye, Canna, and Mull; and in  the north
of Ireland.
   § 2. Radiated zeolite  Stilbite of  Hatty.
Colours yellowish-white and grayish-white.
Massive, in angular  pieces, in prismatic
and granular concretions, and crystallized
in a rectangular four-sided prism, various-
ly  modified by acuminations.    Shining.
pearly.  Translucent.  Hardness and che-
mical  characters as above.  Brittle,.  Sp.
gr. 2.14.  Its constituents are, silica 40.98,
alumina 39.09, lime  10.95,  water 16.5.—
Meyer.  Its  situations  are  as the prece-
ding.—Jameson. *
   • Zero.  The commencement of a scale
marked 0.  Thus we say the zero of Fah-
renheit, which is  32° below  the melting
point of ice; the  zero of the centigrade
scale, which coincides with the  freezing
of water.   The absolute zero is the ima-
ginary point in the scale of temperature,
when  the whole  heat is exhausted; the
term of absolute cold, or privation  of  ca-
loric.   See Caloric*
   vox. n.
  •Zimome.  The gluten of wheat, treat.
ed by alcohol, is reduced to the third part
of its bulk.   This diminution is owing not
merely to the loss of gliadine, but likewise
to that of water.  The residue is zimome,
which may be obtained pure by boiling it
repeatedly  in alcohol, or by digesting it in
repeated portions of that liquid  cold, till
it no longer  gives out any gliadine.   See
Gliadine.
   Zimome  thus purified has the form of
small globules, or constitutes a shapeless
mass, which  is hard, tough,  destitute of
cohesion, and of an ash-white colour. When
washed in  water, it  recovers part of its
viscosity, and becomes   quickly  brown,
when left in contact of the air.   It is spe-
cifically heavier than  water.  Its mode of
fermenting is no longer that of gluten; for
when it putrefies, it exhales  a fetid uri-
nous  odour.   It  dissolves completely in
vinegar, and  in the  mineral acids at a boil-
ing temperature.   With caustic potash, it
combines and forms a kind of soap. When
put into lime-water, or into the  solutions
of the  alkaline  carbonates,  it becomes
harder, and  assumes a  new appearance
without dissolving.   When  thrown  upon
red-hot coals, it  exhales an odour similar
to that oftburning hair or hoofs, and burns
with flame.
   Zimome  is to be found in several  parts
of vegetables.  It produces various kinds
of fermentation, according to the nature
of the substance  with which  it comes in
contact.*
   Zinc is a metal of a bluish-white colour,
somewhat brighter  than lead; of conside-
rable hardness, and so malleable as not to
be broken with  the hammer, though it
cannot be much extended in this way.  It
is very easily extended by the rollers of
the flatting mill.  Its sp. gr. is from 6.9 to
7.2.   In a temperature between  210° and
300° of F., it has so much ductility that it
can be drawn into wire, as well as  lami-
nated; for which a patent has been obtain-
ed by Messrs. Hobson and  Sylvester of
Sheffield.  The zinc thus annealed and
wrought retains the malleability it had ac-
quired.
   When broken  by  bending, its texture
appears as if composed of cubical grains.
On account  of its  imperfect  malleability,
it is difficult to reduce it into small  parts
by filing or hammering; but it may be gra-
nulated, like the malleable metals, by pour-
ing it, when  fused, into cold  water;  or, if
it be heated nearly to melting,  it  is then
sufficiently brittle to be pulverized.
   It melts  long before ignition, at  about
the 700th degree of Fahrenheit's thermo-
meter; and, soon  after it becomes red-hot,
it burns with a dazzling white flame, of a
bluish or yellowish tinge, and is oxidized
                      4.5 
                 ZIN

with such rapidity, that it flies up  in  the
form of white flowers, called the flowers of
zinc, or philosophical wool.  These are  ge-
nerated so plentifully, that  the  access of
air is soon intercepted; and the combustion
ceases, unless the matter be stirred, and a
considerable heat kept up.  The white  ox-
ide of zinc is not volatile, but is driven up
merely by the force of the combustion.
When it is again urged by a strong heat,
it becomes converted into a clear  yellow
glass.  If zinc be heated in closed vessels,
it rises without decomposition.
   * The oxide of zinc, according  to  the
experiments of MM. Gay-Lussac and Ber-
zelius, consists of  100 metal -+- 24.4 oxy-
gen; whence the prime equivalent appears
to be 4.1.   Sir H. Davy makes it  4.4 from
his own and his brother's experiments.
   When zinc is burned in chlorine, a solid
substance is formed  of a whitish-gray  co-
lour;  and semi-transparent.  This  is  the
only chloride of zinc, as there is  only one
oxide  of the  metal.  It may likewise be
made by heating together zinc filings and
corrosive  sublimate.  It is as soft as wax,
fuses at a  temperature a little above 212°,
and rises in the gaseous form at  a heat
much below ignition. Its taste is intensely
acrid,  and it corrodes  the  ski*  It acts
upon water, and dissolves in it, producing
much heat;  and its solution, decomposed
by an  alkali, affords the white  hydrated
oxide  of  zinc.  This chloride  has been
called  butter of zinc, and  muriate of zinc.
From the experiments of Dr. John Davy, it
consists of nearly  equal weights of zinc
and chlorine.  The equivalent proportions
appear to  be,—
          Zinc4-1 -j- chlorine 4.5
      Or Zinc 4.4 -f         4-5-
   Blende  is the native sulphuret of zinc.
The two bodies are  difficult to  combine
artificially.  The salts of zinc possess  the
following general characters:—
   1. They generally  yield colourless solu-
tions with water.
   2. Ferroprussiate  of potash,  hydrosul-
phuret of potash, hydriodate of potash,
sulphuretted hydrogei, and alkalis, occa-
sion white precipitates.
   3. Infusion of galls produces no precipi-
tate.*
   The diluted  sulphuric acid   dissolves
zinc; at the  same time that the tempera-
ture of the solvent is increased,  and much
hydrogen  escapes; an undissolved residue
is left, which has been supposed to  consist
of plumbago.  Proust, however, says, that
it is a mixture of arsenic, lead, and copper.
As the combination  of the sulphuric acid
and the oxide proceeds, the temperature
diminishes,  and the sulphate of zinc, which
is more soluble in hot than cold water,  be-
gins to separate, and disturb the transpa-
rency of the fluid. If more water be added,
                ZIN

the salt may he obtained in fine prismatic
four-sided  crystals.  The white vitriol, or
copperas, usually sold, is crystallized has-
tily, in (he same manner  as loaf-sugar,
which on this  account  it  resembles in ap-
pearance; it  is slightly efflorescent.  The
white oxide of zinc is soluble  in the sul-
phuric" acid,  and forms the same salt as is
afforded by zinc itself.
  The hydrogen  gas,  that  is  extricated
from water by the action of sulphuric acid,
carries up with it a portion of zinc, which
is apparently dissolved in it; but this is de-
posited spontaneously,  at least in part, if
not wholly, by standing.  It burns with a
brighter flame  than common hydrogen.
  Sulphate of zinc is prepared in the large
way from some varieties of the native sul-
phuret.  The ore  is roasted,  wetted with
water, and exposed to  the air.  The sul-
phur attracts oxygen, and is converted into
sulphuric acid; and the metal, being at the
same   time oxidized,  combines  with  the
acid.   After some time,  the sulphate is ex-
tracted by solution in water;  and the solu-
tion being evaporated to dryness, the mass
is run into moulds.   Thus the white vitriol
of the shops,  generally contains a small
portion of iron, and sometimes of lead.
  Sulphurous acid dissolves zinc, and sul-
phuretted hydrogen is evolved.  The solu-
tion, by exposure to the air, deposites needly
crystals, which, according to Fourcroy and
Vauquelin, are sulphuretted sulphite  of
zinc.   By dissolving oxide of zinc in sul-
phurous acid, the pure sulphite is obtained.
This is soluble  and crystallizable.
  Diluted nitric acid combines rapidly with
zinc, and produces much heat, at the same
time that a large quantity of nitrous air
flies off.  The solution is very caustic, and
affords crystals by evaporation and cooling,
which slightly detonate upon hot coals, and
leave oxide of zinc  behind.  This salt is
deliquescent.
  Muriatic  acid  acts  very strongly upon
zinc, and disengages much hydrogen; the
solution, when  evaporated, does not afford
crystals, but  becomes gelatinous.  By a
strong heat it is partly decomposed, a por-
tion ofthe  acid being expelled, and part of
the muriate  sublimes  and condenses in a
congeries of prisms.
  Phosphoric acid dissolves  zinc.  The
phosphate does not crystallize, but becomes
gelatinous, and may be  fused by a strong
heat. The concrete phosphoric acid heated
with zinc filings is decomposed.
  Fluoric acid  likewise dissolves zinc.
  The boracic  acid digested with zinc be-
comes  milky; and if a solution of borax  be
added  to a solution  of muria'e or nitrate
of zinc, an insoluble borate of zinc is thrown
down.
  A solution of carbonic acid in water dis-
solves a small quantity of zinc, and more 
ZIN                                   ZIN
readily its oxide-  If the solution he expo-
sed to the  air, a thin iridescent pellicle
forms on its surface.
  The acetic  acid readily  dissolves zinc,
and yields by evaporation crystals of ace-
tate of zinc, forming rhomboidal or hexa-
gonal plates.  These  are  not altered  by
exposure to the air, are soluble in water,
and burn with a blue flame.
  The succinic acid dissolves zinc with ef-
fervescence, and the solution yields long,
slender, foliated crystals.
  Zinc is readily dissolved in benzoic acid,
and the solution yields needle-shaped crys-
tals, which are soluble both in  water and
in alcohol.  Heat decomposes them  by vo-
latilizing their acid.
  The oxalic acid attacks  zinc with a vio-
lent effervescence, and a white powder soon
subsides, which is oxalate of zinc. If oxalic
acid be dropped into a solution of sulphate,
nitrate, or muriate of zinc, the same salt is
precipitated; it  being scarcely soluble in
water unless an  excess of acid be present.
It contains seventy-five per cent of metal.
  The tartaric acid  likewise dissolves zinc
with effervescence, and forms a salt diffi-
cult of solution  in water.
  The citric acid  attacks  zinc with  effer-
vescence, and small brilliant crystals of ci-
trate of zinc are gradually deposited, which
are insoluble in  water. Their taste is styp-
tic and metallic, and they are composed of
equal parts of the  acid and of oxide of
zinc.
  The malic  acid dissolves zinc, and af-
fords beautiful crystals by evaporation.
  Lactic acid  acts  upon  zinc with  effer-
vescence,  and  produces  a crystallizable
salt.
  The metallic acids likewise combine with
zinc.   If arsenic acid be poured on it, an
effervescence takes place,  arsenical  hydro-
gen  gas is emitted, and  a black powder
falls down, which is arsenic in the metallic
state, the zinc having  deprived a portion of
the arsenic, as well as the water, of its
oxygen.   If one part of  zinc  filings  and
two parts of dry arsenic  acid be distilled
in a retort,  a violent detonation takes place
When the retort becomes  red,  occasioned
by the sudden absorption of the oxygen of
the acid by the zinc. The arseniate of zinc
may be precipitated by pouring arsenic acid
into the  solution of  acetate  of  zinc, or
by mixing a solution of an alkaline  arseni-
ate with that  of sulphate of  zinc.   It  is a
white powder, insoluble in water.
   By a similar process zinc may be  combi-
ned with the  molybdic acid,  and  with the
oxide of tungsten, the tungstic  acid of
some, with both of which it forms  a white
insoluble compound; and with the chromic
acid,  the result  of which compound is
equally insoluble, but of an orange-red co-
lour.
   Zinc likewise forms some triple salts.
Thus, if the  white oxide of zinc be boiled
in a solution of muriate of ammonia, a con-
siderable portion is dissolved; and  though
part of the oxide is again deposited as the
solution cools, some of it remains combined
with the acid and alkali in the solution, and
is not  precipitable either by pure  alkalis,
or their carbonates.   This triple salt does
not crystallize.
   If the acidulous tartrate  of potash be
boiled  in water with  zinc filings,  a triple
compound will be formed,  which is very
soluble in water, but not easily crystallized.
This,  like the preceding, cannot be preci-
pitated from its solution either  by pure or
carbonated alkalis.
   A triple sulphate of zinc and iron may be
formed  by mixing together  the sulphates
of iron and of zinc dissolved in water, or by
dissolving iron and zinc in dilute sulphuric
acid.  This salt crystallizes in rhomboids,
which nearly resemble the sulphate of zinc
in figure, but  are of a pale  green colour.
In taste, and in degree of solubility, it dif-
fers little from the sulphate of zinc. It con-
tains a much larger proportion of zinc than
of iron.
   A triple sulphate of zinc and cobalt, as
first noticed by Link, may be obtained by
digesting zaftre in a solution of sulphate of
zinc.  On evaporation, large quadrilateral
prisms are obtained, which effloresce on
exposure to the air.
   Zinc is precipitated from acids by the
soluble  earths and the  alkalis:  the latter
redissolve the precipitate, if they be added
in excess.
   Zinc decomposes, or alters,  the  neutral
sulphates in  the  dry way.  When fused
with sulphate  of  potash, it  converts  that
salt into a sulphuret: the zinc at the same
time being oxidized, and partly dissolved
in the  sulphuret.  When pulverized  zinc
is added to fused nitre, or projected toge-
ther with that salt into a red-hot crucible,
a very  violent detonation takes place; inso-
much that it is necessary for the operator
to be careful in using oniy small quantities,
lest the burning matter should be thrown
about.  The zinc is oxidized, and part of the
oxide combines with the alkali, with which
it forms a compound soluble in water.
   Zinc decomposes common salt, and also
 sal ammoniac, by combining with the mu-
 riatic acid   The filings of zinc likewise
 decompose alum, when boiled in a solu-
tion  of that salt, probably by  combining
 with its excess of acid.
   Zinc may be combined with phosphorus,
 by projecting small pieces of phosphorus
 on the zinc melted in a crucible, the  zinc
 being  covered with  a little resin, to pre-
 vent its oxidation.  Phosphuret of zinc is
 white, with a shade of bluish-gray, has a
metallic lustre, aud  is a little, malleable. 
ZIR
ZOI
When zinc and phosphorus are exposed to
heat ih a retort, a red sublimate rises, and
likewise a bluish sublimate, in needly crys-
tals, with a metallic  lustre.  If zinc and
phosphoric acid be  heated together, with
or without a little charcoal, needly crystals
are Sublimed, of a silvery-white colour.  All
these, according to  Pelletier, are phosphu-
retted oxides of zinc.
  Most of the metallic combinations of zinc
have been already treated of.  It forms  a
brittle  compound with  antimony;  and its
effects on manganese, tungsten, and mo-
lybdena, have not yet been ascertained.
  ZtRcoNiA was first  discovered  in  the
jargon of Ceylon by Klaproth, in 1789, and
it has since been found in the jacinth.  To
obtain it, the stone  should be calcined and
thrown into cold Water, to render it friable,
and then powdered in  an  agate  mortar.
Mix the powder with nine  parts of  pure
potash, and project the mixture by spoon-
fuls into a red-hot crucible, taking care
that each portion is fused before  another
is added.  Keep the wbple in fusion, with'
an increased  heat,  for an  hour and  half.
When cold, break the crucible, separate its
contents, powder, and boil in water, to dis-
solve the alkali.  Wash  the insoluble part;
dissolve  in muriatic acid; heat the solution,
that the silex may fall down; and precipi-
tate the zircon by caustic fixed  alkali.  Or
the  zircon may be precipitated by carbo-
nate of soda, and the carbonic  acid expel-
led by heat.
  * New Process for preparing pure Zirconia.
   Powder the zircons very fine, mix them
with two parts  of  pure  potash, and heat
them red-hot in a  silver crucible, for an
hour.  Treat the substance obtained with
distilled water, pour it on a filter, and
wash the insoluble part  well; it will be a
compound of zirconia, silex, potash, and
oxide of iron.   Dissolve it in muriatic acid,
 and evaporate to dryness, to separate the
 silex.   Redissolve the muriates of zirconia
 and iron in water;  and to separate the zir-
 conia which adheres to  the  silex, wash it
 with weak muriatic acid, and  add this  to
  he solution.   Filter the fluid, and preci-
 pitate the zirconia and  iron by pure am-
 monia; wash the precipitates well, and then
 treat the hydrates with oxalic acid, boiling
 them  well together, that the acid may act
  on the iron, retaining it in solution, whilst
  an insoluble oxalate  of  zirconia is formed.
  It is then to be filtered,  and  the oxalate
  washed, until no iron can  be  detected in
  the water that passes.   The earthy oxalate
  is, when dry, of an opaline colour.  After
  being well washed, it is to be decomposed
  by heat in a platinum crucible.
    Thus obtained,  the zirconia is perfectly
  pure, but is not affected by acids. It must
  be reacted on by potash as before, and then
  "Washed until the  alkali is  removed.  Af-
terwards dissolve it in muriatic acid, and
precipitate  by ammonia.   The  hydrate
thrown down, when well washed, is per-
fectly pure, and easily soluble  in  acids.—
MM. Dubois and Silveira, Ann.  de Chime,
et de Rhys. xiv. p. 110.*
   Zirconia is a fine white powder, without
taste or smell, but somewhat harsh to the
touch.  It is insoluble  in water; yet  if
slowly dried, it coalesces into a semi-trans-
parent  yellowish mass, like gum-arabic,
which retains one-third its weight of w«-
er.  It  unites with  all  the  acids.  It is
insoluble in pure alkalis; but  the  alka-
line carbonates dissolve it.  Heated with
the blow-pipe, it  does not melt, but emits a
yellowish phosphoric  light.  Heated in a
crucible of charcoal,  bedded  in charcrtal
powder, placed  in a  stone  crucible, and
exposed  to a good  forge fire for  some
hours, it undergoes a pasty fusion,  which
 unites  its  particles  into  a gray opaque
mass, not truly vitreous, but more resem-
bling porcelain.   In  this state it is suffici-
ently bard  to strike  fire  with  steel, and
 scratch glass; and is  ofthe specific gravity
of 4.3.
   * There is the same evidence for believ-
 ing that zirconia is a compound of a metal
 and oxygen, as that afforded by the action
 of potassium on the other earths. The al-
 kaline  metal, when  brought into contact
 with zirc< nia ignited to whiteness,  is, for
 the  most part, converted into  potash,  and
dark particles, which, when examined  by
 a magnifying glass, appear metallic in some
 parts, of a chocolate-brown in others,  are
 found  diffused  through the  potash  and
 the decompounded earth.
   According to  Sir  H. Davy,  4.66  is  the
 prime equivalent of zirconium on the oxy-
 gen scale, and 5.66 that of zirconia.*
   *Zoisite. A sub-species  of prisma-
 toidal  augite, which is  divided into  two
 kinds, the common and friable.
   §1.  Common zoisite.  Colour  yellowish-
 gray., Massi e, in granular and prismatic
 concretions, and crystallized  in very  ob-
 lique four-sided prisms, in which the  ob-
 tuse lateral edges are  often  rounded, so
 that the  crystals have a reed-like form.
 Shining, or glistening  and  resino-pearly.
 Cleavage, double.  Fracture small grained
 uneven.   Feebly translucent.   As hard as
  epidote.  Very   easily  frangible.  Sp. gr.
  3.3. It is affected by the blow-pipe, as epi-
  dote.  Its constituents  are, silica 43,  alu-
  mina 29, lime 21, oxide of iron 3.—Klap-
  roth.   At  the  Saualp  in  Carinthia, it is
  found imbedded in a bed of quartz, along
  with cyanite, garnet, and augite; or it takes
  the place of feldspar in a granular rock,
  composed of quartz and mica.   It is found
  in Glen Elg in Invernessshire, and  in Shet-
  land.
    % 2. Friable zoisite.  Colour reddish-white, 
                 zoo

which is spotted with pale peach-blossom
red.  Massive, and  in  very fine loosely
aggregated granular concretions.  Feebly
glimmering.   Fracture  intermediate  be-
tween earthy  and splintery.  Translucent
on the edges.  Semi-hard.  Brittle. Sp. gr.
3.3.  Us constituents are, silica 44, alu-
mina 32, fime  20, oxide of iron 2.5—Klap-
roth.  It occurs imbedded in green  talc,
at Radelgraben in Carinthia.*
   Zoophytes.  Scarcely any chemical ex-
periments have been  published on these
interesting subjects, if we except the ad-
mirable  dissertation by Mr. Hatchett, in
the Philosophical Transactions for 1800.
 From  this  dissertation, and from  a few
 experiments  of> Merat-Guillot,  we  learn,
 that  the  hard  zoophytes are  composed
 chiefly of three ingredients:  1. An animal
 substance of the nature of coagulated al-
 bumen, varying in  consistency; sometimes
 being gelatinous  and almost liquid, at
 others  of the  consistency  of  cartilage.
 2.  Carbonate  of lime.  3.  Phosphate of
 lime.
   In some zoophytes, the animal matter is
 very scanty, and phosphate of lime wanting
 altogether;  in others the animal matter is
 abundant, and the  earthy  salt pure carbo-
 nate of lime; while in others  the  animal
 matter is abundant, and the  hardening salt
 a mixture of carbonate of lime  and phos-
 phate of lime; and  there is  a  fourth class
 almost destitute of earthy salts altogether.
 Thus, there are four classes of zoophytes;
 the first resemble porcellaneous shells; the
 second  resemble   mother-of-pearl  shells;
 the third resemble crusts; and the fourth
 horn.
    1. When the madrepora virginea  is im-
 mersed in diluted nitric acid, it effervesces
 strongly, and is  soon dissolved.  A few
 gelatinous  particles float in the solution,
 which is otherwise transparent and colour-
 less.  Ammonia precipitates nothing; but
 its carbonate throws  down abundance of
 carbonate of lime.  It is  composed, then,
 of carbonate of lime  and a little  animal
 matter.  The  following  zoophytes yield
 nearly the same results:—
        Madrepora muricata,
        -----—  labyrinthica,
        Millepora cerulea,
        ---------alcicornis,
        Tubipora musica.
    2. When the madrepora ramea is plunged
 into weak nitric acid, an effervescence is
 equally produced;  but after all the soluble
 part is taken  up, there remains a membrane
 which retains completely the original shape
 of the  madrepore.  The substance taken
 up is pure lime. Hence, this madrepore is
 composed of carbonate of lime, and a mem-
 branaceous substance, which, as in mother-
 of-pearl shells, retains  the figure ofthe
                ZOO

madrepore.  The following zoophytes yield
nearly the same  results:—
      Madrepora fascicularis,
      Millepora cejlulosa,
      -----— fascialis,
      ---------truncata,
      Iris hippuris.
   The following substances, analyzed by
 Merat-Guillot, belong to this  class from
 their composition,  though  it is difficult to
 say what are  the  species  of zoophytes
 which were analyzed.  By red coral, he pro-
 bably meant  the gorgoma nobilis,  though
 that  substance is known, from  Hatchett's
 analysis, to contain also some phosphate:—
                 White  Red   Articulated
                 coral, coral.   coralline.
 Carbonate of lime, 50   53.5      49
 Animal matter,    50   46.5     51

                   100 100.0    100*
   3.  When  the madrepora polymorpha  is
 steeped in weak nitri#acid, its shape con-
 tinues unchanged;  there remaining a tough
 membranaceous substance of  a white co-
 lour and  opaque, filled with a transparent
 jelly.  The acid solution yields a slight
 precipitate  of  phosphate of  lime,  when
 treated with ammonia, and carbonate  of
 ammonia throws down  a  copious precipi-
 tate of carbonate of lime.   It is composed,
 therefore,  of animal  substance,  partly  in
 the  state of jelly,  partly  in that of mem-
 brane, and hardened by carbonate of lime,
 together with a little phosphate of lime.
    Flustra foliacea, treated in  the same
 manner,  left a finely reticulated membrane,
 which  possessed the properties of coagu-
 lated albumen.  The solution  contained a
 little phosphate of lime, and yielded abun-
 dance  of carbonate of lime when  treated
 with the alkaline carbonates. The corallina
 opuntia, treated in the same manner, yield-
 ed the same constituents; with this differ-
 ence, that no phosphate of lime could be
 detected in the fresh coralline, but the  so-
 lution  of burnt coralline yielded traces of
 it.  The iris ochracea  exhibits  the  same
 phenomena, and is formed of the same con-
 stituents.   When  dissolved in weak nitric
 acid, its colouring matter falls in the state
 of a fine red  powder,  neither soluble in
 nitric  nor muriatic acid, nor changed by
 them;  whereas the tinging matter of the
 tubipora musica is destroyed by these acids.
 The branches of this iris  are divided by a
  series of knots.  These knots are cartila-
  ginous  bodies connected  together  by a
  membraneous  coat. Within this coat there
  is a conical cavity filled with the earthy or
  coralline matter; so that, in the recent state,
  the branches ofthe iris are capable of con-

   t Merat-Guillot,  Ann. de Chim. xxxiv. 71. 
zoo
tflN
siderable motion, the knots answering the
purpose of joints.   See Coral.
  Mr. Hatchett analyzed many species of
sponges, but found them all similar in their
composition.  The tpangia  cancellata, ocu-
lata, infundibuliformis, palmatu,  and offici-
nalis,  may be  mentioned  as specimens.
They  consist of gelatin, which they gra-
dually give out to water, and a thin brittle
membranous substance,  which possesses
the properties of coagulated albumen.
  * Zumates. Combinations ofthe zumic
acid with the salifiable bases.*
  • Ziimic Acid.  See Acid (Zumic).#
  Zundererz,.  Tinder ore.  An ore of
silver. 
APPENDIX,
* Containing several Tables referred to in the body of the Work.  Many important
Tables usually placed at the end of Chemical Treatises are inserted under the particular
articles to which they belong.  Thus the Tables of the Mineral Acids  will be found
under Acid (Muriatic), (Nitric), and (Sulphuric).   For others, see Acid in
general, Alcohol, Attraction, Caloric, Climate, Coal-gas, Combustion,
Equivalents, Electricity, Gas, Hydrometer, Light, Metal, Rain, Salt,
Water (Mineral), Wine, &c. &c.
           I.—Dr. Wollaston's Numerical Table of Chemical Equivalents.

Dr. Wollaston's numbers represent the weights of the atoms of bodies, oxygen being
                                  called ten.
 1.
 2.
 3.
 4.
 5.
 6.
 7.
 8.
 9.
10.
11.
12.
13.
14.

15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.

28.

29
Hydrogen       *
Oxygen     ....
Water.....
Carbon     ....
Carbonic acid (20 oxygen)
Sulphur     ....
Sulphuric acid (30 oxygen)  -
Phosphorus -    -    -     -
Phosphoric acid (20 oxygen)
Azote or Nitrogen
Nitric acid (50 oxygen)
Muriatic acid, dry
Oxymuriatic acid (10 oxygen)
Chlorine 44.10 + 1.32 hydro-
  gen = muriatic acid gas
Oxalic acid -    -    -     -
Ammonia  .    -    -     -
Soda.....
Sodium  (above —10 oxygen)
Potash.....
Potassium (above —10 oxygen)
Magnesia                 *
Lime                     ■
Calcium (above — 10 oxygen)
Strontites  .    -    -
Barytes     -
Iron  -   -    -    -
Black oxide (10 oxygen)
Red oxide (15 oxygen)
Copper     -
Black oxide (10 oxygen)
Zinc  -
Oxide (10 oxygen)
Mercury    -
Red oxide (10 oxygen)
  1.32
 10.00
 11.32
  7.54
 27.54
 20.00
 50.00
 17.40
 37.40
 17.54
 67.54
 34.10
 44.10

 45.42
 47.0
 215
 39.1
 29.1
 59.1
 49.1
 24 6
 35.46
 25.46
 69.00
 97.00
 34.50
 44.50
 49.50
 40.00
 50.00
 41.00
 51.00
125.50
135.50
Black oxide (125.5 mercury)    261.00
Lead.....129.50
Litharge (10 oxygen)  -    -   139.50
Silver.....135.00
Oxide (10 oxygen)    -    -   145.00
Sub-carbonate of ammonia -    49.00
Bi-carbonate (27.5 carbonic acid) 76.50
Sub-carbonate of soda -    -    66.60
Bi-carbonate (27.5 C. A. + 11.3
  water)    ....   105.50
Sub carbonate of potash    -    86.00
Bi-carbonate (27-5 C. A. -f- 11.3
35.
36.
37.
38.
39.

40.

41.
42.
  water)
Carbonate of lime
            barytes
— lead
125.50
 63.00
124.50
167.00
 50.00
s'ulphuric acid dry
Do. sp. gr. 1.850 (50 + 11.3
  water)    ....    61.30
Sulphate of soda (10 water =
  113.2)    ....   202.30
Sulphate of potash    -     -   109.10
Sulphate of magnesia dry   •    74.60
Do. crystallized (7 water =
  79.3)      ....   153.90
Sulphate of lime dry  -     -    85.50
Crystallized (2 water = 22.64) 108.10
Sulphate of strontites  -     -   119.00
---------- barytes    -     -   147-00
,           copper (1  acid + 1
             oxide -f- 5 water) 156.60
__________iron (7 water) .     173.80
__________zinc (do.)  -    ,  180.20
________—lead -    -    -   189.50
Nitric acid dry   -    -     -    67.54 
   Nitric acid, sp. gr. 1.50 (2 water
      = 22.64) -
51. Nitrate of soda   -
52.--------potash -
53.--------lime
54.--------barytes
55.---.----lead   -
56. Muriate of ammonia
57.-------- soda
58. —-----— potash -
   Oxymuriate of do. (60 oxygen)
        59. Muriate of lime   -
 90.20  60---------barytes
106.60  61---------lead   -
126.60  62---------silver -
103.00  63.--------  mercury
164.50  64. Sub-muriate of do. (1 acid
207.00       oxygen + 2 mercury)
 66.90  65. Phosphate of lead
 73.20  66. Oxalate of lead   -
 93.20  67. Bin-oxalate of potash  -
153.20
+ 1
169.60
131.00
173.60
179.10
170.10

296.10
176.90
186.50
153.00
  * TABLES exhibiting a collective View of all the Frigorific Mixtures
                contained in Mr. Walker's Publication, 1808.


II.—TABLE, consisting of Frigorific Mixtures, having the Power of generating, or cre-
   ating Cold, without the aid of Ice,  sufficient for all useful and Philosophical purposes,
   in any part of the World, at any Season.

                     FRIGORIFIC MIXTURES WITHOUT ICE.
MIXTURES.	Thermometer sinks,	Deg. of cold produced.
Muriate of ammonia - - 5 parts Nitrate of potash - - 5 Water - - - - 16	From + 50° to -+- 10°	40°
Muriate of ammonia - - 5 parts Nitrate of potash - - 5 Sulphate of soda - - 8 Water - - - - 16	From -f- 50° to -+- 4°	46
Nitrate of ammonia - - 1 part Water .... 1	From -f- 50° to -+- 4°	46
Nitrate of ammonia - - 1 part Carbonate of soda - - 1 Water .... 1	From -r- 50° to — 7° 57	
Sulphate of soda - - 3 parts Diluted nitric acid - - 2	From -f- 50° to — 3°	53
Sulphate of soda - - 6 parts Muriate of ammonia - - 4 Nitrate of potash - - 2 Diluted nitric acid - - 4	From + 50° to — 106	60
Sulphate of soda - ' - 6 parts Nitrate of ammonia - - 5 Diluted nitric acid 4	From + 50° to — 14°	1 64
Phosphate of soda - - 9 parts Diluted nitric acid 4	From -4- 50° to — 12°	62
Phosphate of soda 9 parts Nitrate of ammonia - - 6 Diluted nitric acid - - 4	From + 50° to — 21"	71
Sulphate of soda 8 parts Muriatic acid ... 5	From + 50° to 0°	50
Sulphate of soda - . 5 parts Diluted sulphuric acid - 4	From -f 50° to + 3°	47
   N. B.—If the materials are mixed at a warmer temperature, than that expressed in
the Table, the effect will be proportionably greater; thus, if the most powerful of these
mixtures be made, when the air is ■+- 85°, it will sink the thermometer to -+■ 2*. 
III.—TABLE consisting of Frigorific Mixtures, composed of Ice, with chemical Salts if Acids
                                Frigorific Mixtures with Ice.
M1XTURKS.	1		Thermometer sinks.	Deg. of cold produced.
Snow, or pounded ice -Muriate of soda -	2 parts 1	5 t	to —5°	•
Snow, or pounded ice -Muriate of soda -Muriate of ammonia -	5 parts 2 1		to-,12°	•
Snow, or pounded ice -Muriate of soda -Muriate of ammonia -Nitrate of potash	24 parts - 10 5 5 12 parts 5 5		to —180j	*
Snow, or pounded ice -Muriate of soda -Nitrate of ammonia			to—25°	55
Snow - - - -Diluted sulphuric acid -	3 parts 2	From •+• 32° to — 23°		
Snow - - - -Muriatic acid	8 parts 5		From -+- 32° to — 27°	1 *
Snow - -Diluted nitric acid	7 parts 4	From -+- 32° to — 30°		62
Snow - - - -Muriate of lime -	4 parts 5	From -+- 32° to — 40°		72
Snow - - - -Crvst. muriate of lime -	2 parts 3		From + 32° to — 50°	821
Snow - - - -Potash -	3 parts 1 - 4 |		From -4- 32' to — 51°	I 83
 N.B.-The reason for theomi.s'ion, in the last column of this T^^^™^^,^,,,,,, of
tures to the degree mentioned in the preceding column, and never lower, whatever ma> ne       y
the materials at mixing.                                                                ,
 IV. -TABLE consisting of Frigorific Mixtures selected from ^e foregoing^abUs, and
           combined so as to increase or extend Cold to the extremest Degrees.
                             Combinations of Frigorific Mixtures._________
MIXTURES.
Thermometer sinks.
Phosphate of soda
Nitrate of ammonia
Diluted nitric acid
Phosphate of soda
Nitrate of ammonia
Diluted mixed acids
Snow  -    -
Diluted nitric acid
Snow  -    -    -
Diluted sulphuric acid
Diluted nitric acid____
Snow  -    -    -
Diluted sulphuric acid
Snow
Muriate of lime -
Snow  -
Muriate of lime -
From 0° to — 34°
From — 34* to — 50°
Deg. of cold
 produced.

     34
3 parts     Frojn Oo tQ _ 46q
From — 10° to — 56°
From ~ 20° to — 60c
3 parts
4
From -+- 20° to
48°
3 parts
4
From + 10Q to — 54c
46
68
Snow  -
Muriate of lime  -
Snow  -
Crvst. muriate of lime -
2 parts
3
From — 15° to — 68c
From 0° to — 66c
From — 40° to — 73e
From — 68° to — 91°
Snow   -----      P"'
Cryst. muriate of lime -     -    3___
Snow':"""-   ""-     -     -    Spar
Diluted!?*^™*^                          to mixing «o thetemperature reo.iretl,
 N. B.-The materials in the first column are toi be^ooiea, pre
bv mixtures taken from either of the preceding t»bi«.                         ^ fi
  Vol. IT. 
V.—TA&LE of Capacities of different Substances for Catonc.
In this Table, the  authorities  are  marked by  the  initials of the respective authors'
  names.   C. Crawford:  K. Kirwan: Ir. Irvine: G. Gadolin: L. Lavoisier: W. Wilcke:
  M.Meyer.
1. Hydrogen gas   -
2. Oxygen gas
3. Atmospheric air
         GASES.
21.4000  C.   4. Aqueous vapour
 47490  —   5. Carbonic acid gas
 1.7900  —   6. Nitrogen gas
1.5500  C
1.6454  -
 .7936  -
 7. Solution of carbonate of
      ammonia,
 8. Solution of brown sugar
 9. Alcohol (15.44)   -
10. Arterial blood
11. Water
12. Cow's milk
13. Sulphuret of ammonia
14. Solution of muriate of so-
      da, 1 in 10 of water
15. Alcohol (9.44)
16. Sulphuric acid, diluted
     • with 10 of water,
17. Solution of muriate of so-
      da, in  6.4 of water
18. Venous blood
19. Sulphuric acid, with 5
      parts of water      •
20. Solution of muriate of so-
       da, in 5 of water   *
21. Nitric acid (39)
22. Solution  of sulphate of
     magnesia, in 2 of water
23. Solution of muriate of so-
       da in  8 of water
 24. Solution  of muriate of so-
       da in 3.33 of water
 25. Solution  of nitrate of pot-
       ash in 8 of water
 26. Solution of muriate of so-
       da in 2.8 of water   •
 27. Solution of muriate  of
       ammonia in  1.5 of water
 28.  Solution of muriate of so-
      da  saturated, or in 2.69
      of  water
 29. Solution of supertartrate of
      potash  in 237.3  of water
 30. Solution of carbonate of
      potash      ...
 31. Colourless sulphuric acid
      (51.55,56,57)
 32. Sulphuric acid,  with 2
      parts of water
1.8510	K.
1.0860	—
1.0860	—
1.0300	C.
1.0000	
.9999	C.
.9940	K.
.9360	G.
.9300	Ir.
.9250	G.
.9050	G.
.8928	C.
.8760	G.
.8680	G.
.8440	K.
.8440  --

.8320  —

.8200  G.

 .8167  L.

 .8020  G.
.7980  K.
.7930  G.

.7650  K.

.7590  —
LIQUIDS.
     33- Solution  of sulphate of
          iron in 2.5 of water
     34. Solution of sulphate of
          soda in 2.9 of water
     35. Olive oil      ...
     36. Water of ammonia, sp.
          gr. 0.997
     37. Muriatic acid, sp. gr. 1.122
     38. Sulphuric acid, 4  parts
          with 5 of water
     39. Nitric acid, sp. gr. 1.29895
     40. Solution of alum in 4.45
          of water    .    .    -
     41. Mixture of nitric acid with
          lime, 9-y to 1
     42. Sulphuric acid, with an
          equal weight of water
     43. Sulphuric acid, 4 parts
          with 3 of  water
     44. Alcohol (9.15)
     45. Nitrous acid, sp. gr. 1.354
     46. Linseed oil
     47. Spermaceti oil  (53)
     48. Sulphuric acid, with i of
            water
      49. Oil of turpentine (52)
      50. Sulphuric acid, with i of
          water
      51. Sulphuric acid (31.55,56,57)
      52. Oil of turpentine (49)
      53. Spermaceti oil (47)
      54. Red wine vinegar
      55. Sulphuric  acid, concentra-
          ted and colourless (31)
      56. Sulphuric  acid, sp. gr.
           1.87058
      57- Sulphuric acid (31.51)
      58. Spermaceti melted
      59. Quicksilver, sp. gr. 13.30
      60. Quicksilver
      61.---------
      62.---------
7340  K
.7580  —

.7490  G.
7280	_
.7100	—
.7080	K.
.6800	—
6631	L.
.6613	—
.6490	M.
.6189	L.
.6050	G.
,6031	L.
.6021	C.
.5760	K.
.6280	—
.5000	C.
.5000	0.
.4720	K.
.4420	G.
.4290	C.
.4000	Ir.
.3990	K.
.3870	—
.3390	G.
.3345	L.
.3330	Ir.
.3200	—
.0330	K.
.0290	L.
.0290	W.
.0280	Ir.
63. Ice
64.—     ...
65. Ox hide with the hair
66. Sheep's lungs
67. Beef of an ox
      SOLIDS.
.9000  K.  68. Scotch fir wood
.8000  Ir.  69. Lime tree wood
.7870  C.  70. Spruce fir wood
.7690  —  71. Pitch pine wood
.7400  —  72. Apple tree wood
.6500 M.
.2600  —
.6000  —
.5800  —
.5700  — 
 t3. Alder Wood
 74. Sessile-leaved oak
 75. Ash wood   ...
 76. Pear tree wood   .
 77. Rice
 78. Horse-beans
 79. Dust of the pine tree -
 80. Pease
 81. Beech
 82. Hornbean wood
 83. Birch wood
 84. Wheat
 85. Elm
 86. White wax
 87. Pedunculated oak wood
 88. Prune tree
 89. Ebony wood
 90. Quicklime, with  water, in
     the proportion of 16 to 9
 91. Barley
 92. Oats
 93. Charcoal of birch wood (99)
 94. Carbonate of magnesia
 95. Prussian blue
 96. Quicklime saturated with
      water and dried
 97. Pit coal
 98. Artificial gypsum
 99. Charcoal (93)
100. Chalk (108)
101. Rust of iron
102. White clay
103. White oxide of antimony
      washed
104. Oxide of copper
105. Quicklime (107)
106. Muriate of soda  in crystals
107. Quicklime (105)
108. Chalk (100)
109. Crown glass
110. Agate, sp. gr. 2.648  -
111. Earthen ware
112. Crystal glass without lead
113. Cinders
114. Sulphur
115. Ashes of cinders
116. White glass, sp.  gr. 2.386
117. White clay burnt
118. Black lead
.5300	M.	119
.5100	—	120.
.5100	_	
.5000	—	121.
.5060	C.	122
.5020	—	123
.5000	_	124
.4920	_	
.4900	M.	125.
.4800	—	126
.4800	—	127
.4770	C.	128
.4700	M.	129
.4500	G.	
.4500	M.	130
.4400	—	131
.4300	—	132 133
.4391	L.	134
.4210	C.	135
.4160	—	136.
.3950	G.	137
.3790	—	138.
.3300	—	139.
.2800	G.	140.
.2777	C.	
.2640	G.	
.2631	C.	
.2564	_	141
.2500	_	
.2410	G.	142 143
.2272	C.	144.
.2272	—	145.
.2239	_	146.
.2260	G.	147.
.2168	L.	148.
.2070	G.	149.
.2000	Ir.	150.
.1950	W.	151.
.1950	K.	152.
.1929	L.	153.
.1923	C.	154.
.1890	[r.	155.
.1855	C.	156.
.1870	w.	157.
.1850	G.	158.
.1830	—	
Sulphur     -    -    .    .1830  K.
Oxide of antimony, nearly
  free of air    -    -    .1666  C.
Rust of iron, ditto ditto    .1666  __
Ashes of elm wood   -    .1402  __
Iron (125.127, 128.132)     .1450  Ir.
Oxide of zinc, nearly freed
  from air       -    -    .1369  C.
White cast iron       -    .1320  G.
White oxide of arsenic    .1260  —
Iron (123.132)        -    .1269  C.
Iron, sp. gr. 7876     -    .1260 W.
Cast iron abounding in
  plumbago     -    -    .1240  G.
Hardened steel       -    .1230  —
Steel softened by fire      .1200  —
Soft bar iron, sp. gr. 7.724  .1190  —
Brass, sp. gr. 8.356 (135)   .1160 W.
Copper, sp. gr. 8.785 (136)  .1140 W.
Brass (133)      -    -    .1123  C.
Copper (133)    -    -    .1111  —
Sheet iron       -    -    .1099  L.
Zinc, sp. gr. 7.154 (143)    .1020 W.
White oxide of tin, nearly
  free of air       -    -    .990  C.
Cast pure copper, heated
  between charcoal, and
  cooled slowly, sp. gr.
  7.907      -     -    -    .990  G.
Hammered copper, sp. gr.
  9150       -     -    -    .970  G.
Oxide of tin       -    -    .960  K.
Zinc (198)         -    -    .943  C.
Ashes of charcoal      -    .909  —
Sublimated arsenic    -    .840  G.
Silver, sp. gr. 10.001   -    .820 W.
Tin (152)    -     -    -    .704  C.
Yellow oxide of lead   -    .680  —
White lead        -    -    .670  G.
Antimony    ...    .645  —
Antimony, sp. gr. 6.107      .630 W.
Tin, sp. gr. 7.380 (147)     .600  —
Red oxide of lead      -    .590  G.
Gold, sp. gr. 19.04     -    .500 W.
Vitrified oxide of lead       .590  G.
Bismuth, sp. gr. 9.861   -    .430 W.
Lead, sp. gr. 11.45     -     .420 —
-----.....352  C.
  * The above capacities of the gases are all erroneous; and those of the other bodies
are probably more or less incorrect.  See Caloric* 
TABLE VI.—Con-espondence of the Thermometers of Fahrenheit and Reaumur, and that
       of  Celsius, or the Centigrade Thermometer of the modern French Chemists.
Fahr. 212	leaum.	Cebi. 100	Fahr. 148	Reanm. 1 51.5	Celsi.	Fnhr. 85	Reauni.	Celii. 29.4	Fahr. 22 21 20 l9	Reaum.	Cell).
	80				64.4		23.5			4.4	5.5
211	79.5	99.4	147	51.1	63.8	84	23.1	28.8		4.8	6.1
210	79.1	98.8	14.;	.■50.6	63.3	83	22.6	28.3		5 3	6.6
209	78.6	98.3	145	5u.2	62.7	82	22.2	27.7		5.7	7.2
208	78.2	97.7	144	49.7	62.2	81	217	27.2	18	6.2	7.7
207	77.7	97.2	143	49.3	61.6	80	21.3	26.6	17	6.6	8.3
206	77.3	96.6	142	48.8	61.1	79	20.8	26.1	16	7.1	8.8
205	76.8	96.1	141	4b.4	60.5	78	20.4	25.5	15	7-5	9.4
204	76.4	95.5	140	48	60	77	20	25	14	8	10
203	76	95	139	47.5	59.4	76	19.5	244	13	8.4	10.5
202	75.5	944	138	41.1	58.8	75	19.1	23.8	12	8.8	11.1
201	75.1	93.8	137	46.6	58.3	74	18.6	23-3	11	9.3	H.6
200	74.6	93.3	136	46.2	57.7	73	18.2	22.7	10	9.7	12.2
199	74.2	92.7	135	45.7	57.2	72	17.7	22.2	9	10.2	12.7
198	73.7	92.2	134	45.3	56.6	71	17.3	21-6	8	10.6	l3.3
197	73.3	91.6	133	44.8	56.1	70	16.8	211	7	11.1	13.8
196	72.8	91.1	132	44.4	55.5	69	16.4	20.5	6	11.5	14,4
195	72.4	90.5	131	44	55	68	16	20	5	12	li
194	72	90	130	43.5	54.4	67	15.5	19.4	4	12.4	15.5
193	71.5	89.4	129	43.1	53.8	66	15.1	18.8	3	12.8	16.1
192	71.1	88.8	128	42.6	53.3	65	14.6	18.3	2	13.3	16.6
191	70.6	88.3	127	42.2	52.7	64	14.2	17.7	1	13.7	17.2
190	70.2	87.7	126	41.7	52.2	63	13.7	17-2	0	14.2	17.7
189	69.7	87.2	125	41.3	51.6	62	13.3	16.6	1	14.6	18.3
188	69.3	86.6	124	40.8	51.1	61	12.8	16.1	2	15.1	18.8
187	68.8	86.1	123	40.4	50.5	60	12.4	15.5	3	15.5	19.4
186	68.4	85.5	122	40	50	59	12	15	4	16	20
185	68	85	121	39.5	49.4	58	11.5	14.4	5	16.4	20.5
184	67.5	844	120	39.1	48.8	57	11 1	13.8	6	16.8	21.1
183	67.1	83 8	119	38.6	48.3	56	10.6	133	7	17.3	21.6
182	66.6	83.3	118	38.2	47-7	55	10.2	12.7	8	17.7	22.2
. 181	66.2	82.7	117	37.7	47.2	54	9.7	12-2	9	18.2	22.7
180	65.7	82-2	116	37.3	46.6	53	9.3	11.6	10	18.6	23.3
179	65.3	81.6	115	36.8	46.1	52	8.8	11.1	11	19.1	23.8
178	64.8	81.1	114	36.4	45.5	51	8.4	10.5	12	19.5	24.4
177	64.4	80.5	113	36	45	50	8	10	13	20	25
176	64	80	112	35.5	44.4	49	7.5	9.4	14	20.4	25.5
175	63.5	79.4	111	35.1	43.8	48	7-1	8.8	15	20.8	26.1
174	63.1	78.8	110	34.6	43.3	47	6.6	8.3	16	213	26.6
173	62.6	78.3	109	34.2	42.7	46	62	7-7	17	21-7	27.2
172	62.2	77.7	108	33.7	42.2	45	5.7	7-2	18	22.2	27.7
171	61.7	77-2	107	33.3	41.6	44	5.3	6.6	19	22.6	28.3
170	61.3	76.6	106	32.8	41.1	43	4.8	6.1	20	23.1	28.8
169	60.8	76.1	105	32.4	40.5	42	4.4	5.5	21	23.5	29.4
168	60.4	75.5	104	32	40	41	4	5	22	24	30
167	60	75	103	31.5	39.4	40	3.5	4.4	23	24.4	30.5
166	59.5	74A	102	31.1	38.8	39	3.1	3.8	24	24.8	31.1
165	59.1	73.8	101	30.6	38.3	38	2.6	3.3	25	25.3	31.6
164	58.6	73.3	100	30.2	37.7	37	2.2	2.7	26	25.7	32.2
163	58.2	72.7	99	29.7	37.2	36	1.7	2.2	27	26.2	32.7
162	57.7	72.2	98	29.3	36.6	35	1.3	1.6	28	26.6	33.3
161	57.3	71.6	97	28.8	36.1	34	0.8	1.1	29	27.1	33 8
160	568	7M	96	28.4	35.5	33	0.4	0.5	30	27.5	34.4
159	56.4	70 5	95	28.0	35	32	0	0	31	28	35
158	56	70	94	275	34.4	31	0.4	0.5	32	28.4	35.5
157	55.5	69.4	93	27-1	33.8	30	0.8	1.1	33	28.8	36.1
156	55.1	68.8	92	26.6	33.3	29	1.3	1.6	34	29.3	36.6
155	54.6	68.3	91	26.2	32.7	28	1.7	22	35	29.7	372
154	54.2	67.7	90	25.7	32.2	27	2.2	2.7	36	30.2	37.7
153	53.7	67.2	89	25.3	31.6	26	2.6	3.3	37	30.6	38.3
152	53.3	66.6	88	24.8	31.1	25	3.1	3.8	38	31.1	38.8
151	52.8	66.1	87	24.4	30.5	24	3.5	4.4	39	31.5	29.4
150	52.4	65.5	86	24	30	23	4	5	40	32	40
149	52	65									
 
* TABLE VII.—Of the Elastic Force of the Vapour of Water in inches of Mercury,
                                  by Dr. Ure.
Temp.	Force.	Temp.	Force.	Temp.	Force.	Temp. 242°	Force.	Temp. 27 °	Force.	Temp.	Force.
24°	0170	115°	2.820	195°	21.100		53.600		86.3ut/	295.6°	130.400
32	0.200	120	3.300	200	23.600	245	56.340	271.2	88.000	295	129.000
40	0.250	125	3.830	205	25.900	2458	57100	273.7	91.200	297.1	133.900
50	0.360	130	4.366	210	28.880	248.5	60.400	275	93.480	298 8	1,7.400
55	0.416	135	5.070	212	30.000	250	61.900	275.7	94.600	300	139.700
60	0.516	140	5.770	216.6	33.400	251.6163.500		277.9	97.800	300.6	140.900
65	0.630	145	6.600	220	35.540	254.5 66.700		279.5	101.600	302	144.300
70	0.726	150	7.530	221.6	36.700	255	67.250	280	101.900	303 8	147.700
75	0.860	155	8.500	225	39110	257.5	69.800	281.8	104.400	305	150.560
80	1.010	160	9.600	226.3	40.100	260	72.300	283.8	107.700	306.8	154.400
85	1.170	165	10.800	230	43.100	260.4	72.800	285.2	112.200	308	157.700
90	1.360	170	12.050	230.5	43.500	262.8	75.900	287.2	,114.800	310	161.300
95	1.640	175	13.550	234.5	46.800	264.9	77.900	289	118.200	311.4	164.800
100	1.860	180	15.160 |235		47.220	265	78.040	290	120.150	1312	167.000
105	2.100	185	16.900 238.5		50.300	267	81.900	292.3	123.10011 Another exper.		
110	2.456	190	19.000,1240		51.700	269	84.900	294	|l26.700|i312°		165.5
* TABLE VIII— Of the Elastic Forces of the  Vapours of Alcohol, Ether, Oil of Turpe
                    tine, and Petroleum, or Naphtha, by Dr. Ure.
Ether.	
Temp.	Force of Vapour.
34°	6.20
44	8.10
54	10.30
64	13.00
74	16.10
84	20.00
94	24.70
104	30.00
Alcoh. sp.gr. 0.813. .Akoh. sp.gr. 0.813.
         Force of
2d. Ether.
105°
110
115
120
125
130
135
140
145
150
155
160
165
170
175
180
185
190
195
200
205
210
 30.00
 32.54
 35.90
 39.47
 43.24
 47.14
 51.90
 56.90
 62.10
 67.60
 73.60
 80.30
 86.40
 92.80
 99.10
108.30
116 10
124.80
133.70
142.80
151.30
166.00
Temp.
 32°
 40
 45
 50
 55
 60
 65
 70
 75
 80
 85
 90
 95
100
105
110
115
120
125
130
135
140
145
150
155
160
165
170
173
178.3
180
182.3
185.3
190
Vapour.

  0.40
  0.56
  0.70
  0.86
  1.00
  1.23
  1.49
  1.76
  2.10
  2.45
  2.93
  3.40
  3.90
  4.50
  5.20
  6.00
  7.10
  8.10
  9.25
  10.60
  12.15
  13.90
  15.95
  18.00
  20.30
  22.60
  25.40
  28.30
  30.00
  33.50
  34.73
  36.40
  39.90
  43.20
Temp.
193.3°
196.3
200
206
210
214
216
220
225
230
232
236
238
240
244
247
248
2491
250
252
254.3
258.6
260
262
264
Force of
Vapour.
 46.60
 50.10
 53.00
 60.10
 65.00
 69.30
 72.20
 78.50
 87.50
 94.10
 97.10
103.60
106.90
111.24
118.20
122.10
126.10
131.40
132.30
138.60
143.70
151.60
155 20
161.40
166.10
Petroleum.
Temp.
316°
320
325
330
335
340
345
350
355
360
365
370
372
375
Force of
Vapour.
30.00
31.70
34.00
36.40
38.90
41.60
44.10
46.86
50.20
53.30
56.90
60.70
61.90
64.00
Oil of Turpen.
Temp.
304°
307.6
310
315
320
322
326
330
336
340
343
347
350
354
357
360
Force of
Vapour.
30.00
32.60
33.60
35.20
3706
37 80
40.20
42.10
45.00
47.30
49.40
51.70
53.80
56.60
58.70
60.80
62.40 
* TABLE IX— New French Weights and Measures (calculated by Dr. DvucAN,/«n.)
1.—Measures of Length: the Metre being at 32°, and tlie Foot at 62°.
	English inches.						
Millimetre	=	.03937					
Centimetre	=	.39371					
Decimetre	=	3.93710					
Metres	=	39.37100	Mil.	Fur.	Yds.	Feet.	la.
Decametre	=	393.71000	= 0	0	10	2	9.7
H«catometre	=	3937-10000	= 0	0	109	1	1
Kilometre	=	39371.00000	= 0	4	213	1	10.2
Myriometre	=	393710.00000	= 6	1	156	0	6
'.—Measures of Capacity.
	Cubic inches.				
Millilitre	= .06103				
Centilitre	= .61028		Eng	lish.	
Decilitre	= 6.10280	Tons.	Hhds.	Wine. G.	Pints.
Litre	= 61 02800	= 0	0	0.	2.1133
Decalitre	= 610.28000	= 0	0	o	5.1352
Hecatolitre	= 6102.80000	= 0	0	26.419	
Kilolitre	---- 61028.00000	= 1	0	12.19	
Myriolitre	= 610280.00000	== 10	1	58.9	
3.—Measures of Weight.
	English Grains.	
Milligramme	= .0154	
Centigramme	= .1544	
Decigramme	= 1.5444	Avoirdupois.
Gramme	= 15.4440	Poun. Oun. Dram
Decagramme	= 154.4402	= 0 0 5.65
Hecatogramme	= 1544.4023	= 0 3 8.5
Kilogramme	= 15444.0234	= 235
Myriogramme	= 154440.2344	= 22 12
TABLE X.—Correspondence of English Weights and Measures with those used in
                       France before the Revolution.
                                  § 1.— Weights.

  The Paris  pound, poids de marc of Charlemagne, contains 9216 Paris grains; it is di-
vided into 16 ounces, each ounce into 8 gros, and each gros into 72 grains.  It is equal
to 7561 English troy grains.
  The English troy pound of 12 ounces contains 5760 English troy grains, and is equal
to 7021 Paris grains.
  The English avoirdupois pound of 16 ounces contains 7000  English troy grains, and
is equal to 8532.5 Paris grains.
       To reduce Paris grains to English troy grains, divide by   ).„. R<J
       To reduce English troy grains to Paris grains, multiply by 3
       To reduce Paris ounces to English troy, divide by         ^ 1 01 ^y/L
       To reduce English troy ounces to Paris, multiply by      5      J
                  § 2.—Long and Cubical Measures.

To reduce Paris running feet, or inches, into English, multiply  by")
English running feet, or inches, into Paris, divide by   -    -     3
To reduce Paris cubic feet, or inches, to English, multiply by     ") ^ n,i€»ro
English cubic feet, or inches, to Paris, divide by  -    -    -     5
1.065977
'. Recently determined by Capt. Kater to be 39.37079 inches.  (Phil. Trans.l8lB,p. 109) 
* TABLE XI—Correspondence between English and other Foreign Weights and Measures.

                        I.—English  Weights and Measures.
Pound.
  1
OtAices.
  12 =
   1 =
  Troy Weight.
Drms.   Scruples.
96  =
1  =
288
 14
  3
  1
   Grains.
 =  5760  =
=   480  =
=    60  =
=    20  =
       1  =
Gal.
 1
               Avoirdupois Weight.
 Pound.   Ounces.  Drms.    Grains.
   1   =   16  =  256 = 7000.
              1  =  16 =   4375
                       1 =    27.34375  =

                    Measures.
  Pints.    Ounces.    Drms.    Cubic. Inch.
=   8 =  128   = 1024 =  231.
     1 =    16   =   128 =   28.875
               1   =    8 =   «1.8047
                        1 =    0.2256
Grammes.
372.96
 31.08
  3.885
  1.295
  0.06475
Grammes.
45325
 28.328
  1.7705
Litres.
3.78515
0.47398
0.02957
0.00396
  N. B.—The English ale-gallon contains 282 cubical inches.
The wine gallon contains 58176 Troy grains; and the wine pint 7272 Troy grains.
                            II.—German.

71 lbs. or grs. English troy -  -  = 74 lbs. or grs. German apothecaries' weight.
 1 oz. Nuremberg, medic, weight = 7 dr. 2 sc. 9 gr. English.
 1 mark Cologne.....= 7 oz. 2 dwt. 4 gr. English troy.


                            III.—Dutch.

       1  lb.  Dutch =    1 lb. 3 oz. 16 dwt. 7 gr. English troy.
     787$  lbs. Dutch = 1038 lbs. English troy.
         IV.—Swedish Weights and Measures, used by Bergmann and Scheele.

  The Swedish pound, which  is divided like the English apothecary or troy  pound,
weighs 6556 grs. troy.
  The kanne of pure water, according to Bergmann, weighs 42250 Swedish grains and
occupies 100  Swedish  cubical  inches.   Hence the  kanne of  pure water  weighs
48088.719444 English troy grains, or is equal to 189.9413 English cubic inches; and the
Swedish longitudinal inch is equal to 1.238435 English longitudinal inches.
                             •
  By Everard's experiment, and the proportions of the English and French foot, as es-
tablished by the Royal Society and French Academy of Sciences, the following numbers
are ascertained:
           Paris grains  in a Paris cube foot of water at 55° F. =   6455U
           English grains in a Paris cube foot of water  - -  =   529922
           Paris grains  in an English cube foot of water  -   =   533247
           English grains in an English cube foot of water   =   437489.4
           English grains in an English cube inch of water   =      253.175

  As  a cubic foot of water weighs  Very nearly 1000 ounces  avoirdupois, the  specific
gravities of bodies  express the ounces in a cubic foot of them, the density of water
being called 1000. 
* TABLE XIT.— Of the Solubility of some Solids in		Water.
NAMES OF SALTS.	Solubility in 100 Parts Water.	
	At 60°	At 212°
Acids.		
Arsenic......	150.	
Benzoic ------	0.208	4.17
		2.
Camphoric -	1.04	8.3
	133.	200.
	8.3	66.
	0.84	1.25
Molybdenic -		0.1
	50.	100.
	0.69	50.
	4.	50.
	Very soluble	
Salifiable Bases.		
	5.	50.
crystallized ...	57.	Unlimited
Lime ------	0.2	
	Very soluble	
Soda......	do.	
Strontites.....	0.6	
crystallized	1.9	50.
Salts.		
Acetate of ammonia -	Very soluble	
barytes - - - -	do.	
lime -	do.	
magnesia ...	do.	
potash - - - .	100.	
soda ....	Very soluble	
strontites ...		40.
Carbonate of ammonia ...	+ 30.	100.
barytes ...	Insoluble	
lime ....	do.	
magnesia	2.	
potash -	25.	83.
soda ....	50.	+ 100.
strontites ...	Insoluble	
Camphorate of ammonia -	1.	33.
barytes ...	0.16	
lime -	0.5	
potash ...	33.	+ 33.
Citrate of soda.....	60.	
lime.....	Insoluble	
Chlorate of barytes - - - .	25.	+ 25.
mercury	25.	
potash - - . -	6.	40.
soda ....	35.	+ 35.
Muriate of ammonia ...	33.	100.
barytes . - - -	20.	+ 20.
lead ....	4.5	
lime ....	200.	
magnesia ...	100.	
mercury ....	5.	50.
potash ....	33.	
silver ....	0-7V	
 
W k VT PC AC CAT TC	Solubility in 100 Parts Water.	
IN AUEa Ur bALlb.	At 60°	At 212°
luriate of soda ....	35.42 '	36.16
strontites	150.	Unlimited
(Urate of ammonia ....	50.	200.
barytes -	8.	25.
lime.....	400.	
magnesia	100.	+ 100.
potash ....	14.25	100.
soda	33. *	+ 100.
• strontites ....	100.	200.
Ixalate of strontites	0-Ts-	
■hosphate of ammonia	25.1	+ 25.
barytes i	0.	0.
# lime ....	0.	0.
magnesia	6.6	
potash - - - -	Very soluble	
soda ...	25.	50.
strontites	0.	0.
'hosphite of ammonia	50.	+ 50.
barytes - - -	o-l	
potash	33.	+ 33.
Jalphate of ammonia	50.	100.
barytes	0.002	
copper ....	25.	50.
iron ...	50.	+ 100.
lead ....	o-tV	
lime	0.2	0.22
magnesia ...	100.	133.
potash •	6.25	20.
soda ....	37.	125.
strontites	0.	0.02
Sulphite of ammonia	100.	
lime	0.125	
magnesia	5.	
potash -	100.	
soda ....	25.	100.
Stccholactate of potash		12.
soda ...		20.
Sub-borate of soda (borax)	8.4	16.8
Super-sulphate of alumina 5c potash (alum]	5.	133.
potash -	50.	+ 100.
Super-oxalate of potash ...		10.
tartrate of potash	ti	3*
Tartrate of potash -	25.	
and soda	20.	
antimony and potash	6.6	33.
Vol. IT.
See Salt.
47 
 
 
CM K ;VIIC AL A I>P A MA T IT $
Pw.l
Plahl
 
CHEMICAL APPARATUS
   In-
PlaUJI.
EmHvJtfx
08
257357�2 
 
 
TIu Que nilCal Sn^HlS <is they occur tit the  Wrilinos />/' Bef^lIirulILnL.!
I  + (Tjl.    Wlrwlic

2  + CB- f^bPhlogisticaUd

3  + (D..........JMrous

4  + (D f^J'blogisticated

5  "*" C7........JMarinc

6  + @ ^f Meplilooisliatfrd

7  »\.........Aqua regia.

8 "*~~lAT -.......of Pluor

Q CHO...........of Arsenic

10 +  C-3.......of Borax

11  +  ®.......of Sugar

1U  +  CT"1. Lof Tartar

13  +  "V-......of Sorrel

2£  +  ^-<.........#f Lemon,

25     J °.........of Benzoin

16 +   (30....*?Amber

If  +  @........of Sugar ofMUk

18  ''F..............Acetous distilled.

JQ  +  @.........orjlfflfc

,26> +  ■/?...........of Ants

XI  +  Q........^.fi^

%'Z +  A........./>f Phosphorus

23  +  ^       •«»*«&

£4  .  iQ)........of Prussian, blue

 'q  rt............Aerial
/_
26    ©/7* PureKaaLVegctabU

21    ©L/"*/* jPk,r« HcedMuunU

Off    (Zf*'/t  tore Volatile.     I
\l

29 ^........-/*»« Ponderous

30 \_/......../kra calcareous

31 ^-f........Pure Mag msian

3% \/.........Pure Argillaceous

33 -^"......Pure Siliceous

34 V.........ffaar

35 A.......Vital.lir

36 -^l ..^.Phlogiston.

37 A........Mater oflfral

38 Q........Sutpher

39 ©  Q.Saline  Hepar

40 \.........Spirit of Wine
     o
 41 0°0.......jBllur
     o
 42 o Q.......Essential Oil

43 (°)........Vacuums Oil
44 ty Q~~&td
45 ^ y^.Platina

46^ J).....SUver

47^ W.....Mcrcur,
48^  fo.../w

49^ Q....Coppcr

50 ^ Q^.-lron

51 y  %......Tin.

52 Sj^ [Jr  Miemulh.

53^t  6.....JVieka
54  + O~0.ufr.renic

55  T  Q   &>i*>i*

56 y Q.....n*

57  +  {_).. —Antimony
58  +  (\j   Manganese

59  T (^ SideriU
(
w+
__^-
Air

Jtater

forth

tlrakU i

       I
    A
   V

 r.A.
...A
    V.......^
    Y ....... tyfuum
 V; C  V;. £«&<v«>iy
 T;CV; ± Quirklina
   >&4......... ntriilabUJv
    A^o.........Fhwrs of*-
    X. ........7ate
 M V     -/%>««*
 AV ©...*«**!
   .V»............Sand
   Q.............a>w  «
 ^'"ZS.........SUrer

   4..........Tin



    z.

   &:

   o-o.


    n:....
  SJVt
   C     .....Calx
Lead.

Memay

Iron   j


 BumuA

 Andmony

 Jteouhu •»,

 Arsenic ■

 Jteauluri^

 Cobalt

 /Ticket
^ 
Plate 111
Tht  Undent  OntEE
3>a^°na.s  or
iBarth
'+t6n«Sihceous Earths


■m Fumble Earths
it-Alum
tofAntimony
p. of Arsenic
«P
^Substances
 COD..............Orpiment


   ^M................Cinnabar


J_.\_>..............Xapis Calanunarie


   03).................Tatty


   (B................Tilriol

0;0............Sea Salt


Q •,<>—•,.........SalGcm


   0.................xVitre


 r—S ; t~/\.—^oraar


 J^.J^...............Sedative Salt







   l~~l...........Tartar


 ^P.Q;........"kali


 0v-; &f-i"*i™l'taati

 0A-; @A v Volatile Alkali


^YL_Q^.........AKld fixed ,llkali

 ..   /T\   .........Caustic fixed Alkali


      /r\K.........Mild rol Alkali


      A»..........Causae vol Alkali
 c.  0*

   TJJ.................H>awA





 i-5tt«...................Vinegar


  ®r-;>-0T Striatic Add.


  0t. >- 0  ^.J/Urota ^M«


  0J.. >■ 0  ;..Jfov/K .4W


   I/. /JiV........Aquafortis


  II h/R ;........Aqua&cgux

     A..........J£/  Sulphureous Add


      *JC*~.........phosphoric Acid


    V...................05ra«


    V..................«5/>im« <><-" #"»"

    VL...............Rcctiiied Spirit of Wine.

   j\*j.................Mther
..Lime TVatzr


...Urine
 Ashes


..ABadi
  CD



 AE;   °Essential Oil

  \P..................Fixed Oils


   £...............-<*+*»■

  LJ  t.........   Hepar of Sulphur

   l\...............  Phosphorus

  rf^k................Phlogiston

   /V.................Soap

   £p..................Peretiorise


  >0..............Gkw

   (^\..................Caput Mortuum


   A\.................. A finrdcr


   E

   B



  \  "II...............Sand bath,

I -wj- Ti..............Vapour bath

   ~\r...................An Hour

    A....................A.Day


    f~\.........„.......A. Night

    wrpt................ A.Mcnth


            A.....jlmalgam
  3.8. 'A &n

  f(^-v Q-........To Distill

  _/-n_    ..........Ub Sublime

  ■^rz..................'& Precipitate

   .—_           A.Retort


  v--v...................An  Alembic

   T  I  M*:.. .  .  ACrueibU
  TVT*;
 jgg^...............Slrattun Super Stratum.


  C.C...............CornwCervl

  £%^_...............^ISottU.

  *Q.i.A.Gr/un.....•<**/' AScruplt    "jl. AJlram

  \J)I An Ounce-......tb i.A.Tound,........flWt/.ft^^ 
Table I. -t'tAe riiaracters to be made tt^-e of in			'	®	A			
Chemistry,			'S:		Bismuth			
n vM :>:<■ 7 Hartcnthin atul .-Met.			-	<P)	AutHmmK Seil'ium			G
2 a ' ■§ I $ [ , ? ^ M l		light	:(©		Chile			
		Caloric		©	Arsenic			r
		Ojru-ien	a	©	Molrbden			c
i '* - l*|-| 1 {such'UH ,,nd * fc § S •§ 3 f fT )-u«C'' Jul'-rtncv				(j) Tungsten			* ,*	ol
				1M 1 Muriatic lB 1 Motoric		\	1 I	a!
JOtaUrronndend as) *=-* !			$	fH Fluoric			<><	
simple Substances, 1 >\		Mo	.jj	cu „™,			"	
IV		B.trvtcs Lime	1	("a*J ^.^ J | Tartar\-ns			Tat Combmauai trith diiKraitSimple.	
«2		Magne.ehl	6	\v 1 Fyivtananvs rn i o:,iii,-IB zj j Ben zoic			the Solid,Iiqui,l,i	
.5 HI J |-a J	V c	Aluminc Stirs-mdnku-n Carbon	•J:				Potash ______Jfe- / Soda-----Mi	
	y	Sulphur	"£	1 B | ; Pyrolignic				
		Fhosphttrus diameters to crpress isudi new cottrfntstible		(P^J j Pyromucic r_Vj 1 Camphoric			Barytes______ Lime	m
		stdvranees as trill be diseoveivd.	j	I 1. 1 I L.ictic j			ALignctia .J-sjuBfl^k \	
\ry-\ <			i	I-Sl] | Sacch.>l<icdc			Alumhie ,.,......... .^^H	
1®		Platini >	|	\Tin\ Formic			Slice_______jHI	
ir.	o ©	Md	1				Hi'J/i.oe/i ....... Ojm	
		Surer '■		|ll/'| Mombic			Carlton________^^H |	
1—1	©	Uem.ry	| t| Lithic >				Sulphur ... _ __^^B \	
^	©	Tin	i|| /^ M"' \				fh.vphorut -_^^^B '	
^N	©	Copper	I \A	^O ' .7/,vVW			CM . .. __MjJ (	
-	©	Lead	UK	V^ -««v</ (W j			Puttina ._^B (	
3	© ©	Iron Hink	^5\	YV i Bitumen			Ji7n-r___________ Mercury	
\P		Manganese	^5 yK | .|-1> [ty.Mu.ns				. r	
	■		----	---				
 
(\wifussio;,

Su(\r&t/tces
XtetHic

J'ld'SiO/U
u»w/ cundAeidirUilie
Hares
yo7i Aeidida/i'e

i\ w/ *c imd Substances
 tell.

 is  or  Caloric

 $ubslancej;prodtnino

intlAtriibiiii Stares.
Solid   \Liguid  Jerirorm
   ■   1-------  '----  -~*

/      V      <
A	iA A
A	A A
V	V ; W
V	k?'W
^	\7 w
V	y w
V	y w
D	© p
C	C ip
u	U V
n	in-o
O	©!©
©	©1©
©	©'©
I®	!©;©
:©	I© ©
	SoUct Liquid yttriternt	
Copper	© 1 © 1 0	
Lead .	©!©!£>'	
1 Lrvn.______	©	©!©
Zitil:	©	©l©
Mmg.ine.rc.........	© I© 0	
J&Av< .	0 ©'@	
Misi mull .	© ©!©	
Atttiinony............	©!©i©	
Arsenic i.	© t©<©	
M.tybdcna.........	© | © , 0	
TuniTsttn „ ...	© ; 0 |0	
Muriatic Radical	ED tO p	
Motoric Ka.ical	CO tO P to to p	
Fluoric Radical		
Succinic Radiol	m to p	
Acetous Ma. iicul	GO tO P	
| Torturous- Radical......	m to p	
fyrotartarous Radical .	\f\ \r] p	
Oxalic Rtuluul	ED tO P	
liodic Aadu'al	ED tO P	
Cdiic Radical	ED tO P	
Sialic Radical	El tiD p	
Relizoic Jladical	ED tO P	
I Fyniu'rac Radical	od to p	
Camphoric Radical	eh to p	
Lactic JLiJicaZ-*—..	ED tO P	
Sacclwlactic Radic.d	EO P P	
1 Formic littdit'.d ....	E fel [3	
1 Fiussic Radical----	[0 to p	
Sebacic Radical----	ED | tO p	
	ED	tO P
Solid   Liquid  dcrifc,
m
ej

Alhohol   .  .         i


                  Table JIT.

         Thektunn C'oitibuiatiuiisof'

     Ox 1 g" C 1\ and  i I i\ 10 I" IC

          »7//i ilifTerctuSubsCiUues.

 .J&n >a.j' <A&f*_......_.-


^Xiirows' Acid into*___


 A'itroits Acid_______ ....__


.Jv'itric Acid     ___..<______


 t\ciae/u2ed JVitric Acul„_____


.Ice             _______ .


 littik-r


 Jfap&ur c/' Water.....


 Ctiri'onir Aitf Gas'.........._______


 Suiphurcw t'oidti Gas...............


 Sulpihureus Acid tiaj'~........._.....


 Suipluwcus Acid


 liquid SuZpTturie Acid---


 Concrete Sidpliurtc- Acid


 Concrete j?/usp/wr<tus Add


 Liquid Phosphorous Acid


 Liquid Plwsplwric Acid........


 Liquid JUUriatic Acid  . ... ..


 Muriatic\Acid Gas....... . ..


 Ojcurenized Muriatic Acid  Our


 Liquid < U-u ■««*.€ tt  tounaat  tcui


 ("(/ttvwc ■ 'a fyenizt &  liaiad- . u


 Corn nxv 3i iuczc At id


  Fluoric   id- triu


  LOftcrctx Su £i/uc Arid


  LiquuX < zrtar ,.**> Acui


 C< vwrvte taiYarc <*« Acul


 jLu, ■■> ™, t}'rv&utarou^  At ut
r


\tL
k.
u_
J
r

r


u

n-

K



 tZl

 DEL
 m
 CO.
 I—I
 LLT
 CD-
 to- 
Continuation ot' Table-III.
Liquid Acetous Acid


Acetous Arid Otis


Liquid .-u'elic Acid


Concrete Orotic Acid


Liquid Gallic Arid


Liquid Citric Arid


Liquid Malic Acid  '


Concrete Benzoic Arid


liqtudFfrvbatuous Arid


Liquid' Pyromua'tts Arid


Concrete Camphoric Acid


Liquid Lactic Arid


Concrete Saccholactic Arid


Liquid Formic Arid


Prussic Arid Gits


Liquid Sebacic Arid


liquid BomhicAad


(Xride of Tungsten


Tunastic Arid


(lade of Molybdena


Concrete Jtolybdic Arid


Oride of Arsenic


Concrete Arsenic Arid


Oride of Cobalt


Oxide of Antimony


Oxide of Bismuth


Oxide of Jfic&xl


Oride of Muufanese


Oxide of/ink


Oride of Inm


Oxide of Lead


Oxide of Copper


Oxide of Tin


Oxide of Ataxia?


Oride ofSHrcr


Oxide or'Gold


Oxide of lutaiki
EL
EEL
EL
EL
tEL
EZL
E>
©
GEL
EL
EL
EO.
na.
HE
IbTI
0"
©.
©"
©.
©

gr
er
gr
gr
gr
gr
©"
©"
©"
gr
gr
gr
a
©
             Table II.

Combinations oi' Tiro Substances.

    (alone tonus a thint in some

       of the. e Compositions.
Ammonitual Gar



Concrete Anunonia



Carburetted Jtentyeu Gas



Sulphuretted .Vurrye/i Cite



Carl'tirrtted Jlidtooett Gas



Sutpluimted lluinyen Gas



Fhosphuretud llidroocn (ia.



Sulphuret ot' Potash



Sulphuret of Soda



Sulphuret of Barytes



Sulphutet of Lime



Sulphuret ofAbtnii/te



Sulphuret at'Gold



Sulphuret. ■/' Silver



Sulphuret of Atervtirr



Sulphuret of Jul



Sulphuret of Copper



Stuphuret of Lead



Sulphuret of Iron



Sulphuret of Zink



Sulphuret ofjtickel



Sulphuret ot'Bisnmdi



Sulphuret of Antimony



Stuphuret of Cocult



Sulphuret of Arsenic



Sulphuret of Molylxlcna



Phosphuret of Lead



flwsphuret of Iron



Alto, offiaunu Sc Gold



.___of Platiiui d Silver



____of Gold XSitirr
¥
                  Table- V.

         JNeulrnl  Salts compared
          ot' Three Subftanees.
      h/oeic is not tuptrsit bemuse titer tur
Vs  wll sttpposd to be. in the solid state. ThtAm


8  '

8
nwniaatlSalts are composdot '4Sub?iium,
8
8
8
8
8
8
8
8
8
Acetat of Lime .



________Alunune



__—_ Jtaq/wsia.
.Potash


. Soda


. Capper



. Jnm
Acetic of Ammonia



_______Pota-rh



_______lime  ...
VOL


AE

AE

 OE.

 SE

JE
Am-

VE

API
OB*

VELk 
TUtte H' Continued.
CttrvoMt of Moiincsia

  •'______Iron

Bentnu of Potash

   p      Ammoniil

         lime

!fionuWSmla

  .'.    dmmonia

  JpJ   time

j Cdmpkanil ot' Potash

!__________ Amnion

■■______'     Lime

\cintt of' Soda
ll
II   ^
I   j;' Ammonia
  A.' ! fc .



 /lat/ ,<fPot,ish

   l     Ammonia

 ____ .Zi/W*:

 Fottniat of Soda
. Linie
llacuu otSoda

 !_____ Amnwtua



il InuSfal ofjbtash
j!
IJfoto of Potash

Muriat of Potash

   ______JVv/d

   _____Amnuuua

   _____Barytes
 V\__ J O.n'ninriar of Soda
 ®£.» I Mitnir of I'otash
AETH I_______ .frxij
   IB'I I_________Auuiwnui
 V/lBil j_______Ajp/t.
 /S^TbI 1_______JVAr/
 PQQ.  .V*ir «./-■/•.*«*

 WL
 AE1
 PEEL
 VOL
 AJH

 PEL
 VE1
 Am
.Lmn
e3H
wl
AF1
pa

AEL
/^EL

AFl
drain of Potash

Acidulous O.nihir of Potash

Phosphor of Potash

Phe*sphat of Soda

Phosphiit of Ananonia

Phosphat of Lime

Phasphar of Iron

Phosphit of Soda

Prussiar of Iron

Pyrvtnrtrit of Potash

fyrvmucit of Sodit

tvroliqnit of Ammonia

Saccholat ot Potash

Sebat of Soda

Sulpha of Potash

Sidphat of Potash  .

Acidulous Sulphur of Potash
AFfl
AS
Ann
PEL
Ann.
©EL
Sulphat of Potash
        trith excess of base.

Sulphat of Soda

Acidulous Sulphat of Soda.

Sidphat of Soda
       ■ trim excess of base.
Sulpluit of Imnumia

 tridutous Sulphat of.tnunonia
/Mm! \ Sidphat ot' Ammtmia
      ~|          with c.rcesj of base.
AZ.
        Sulplua of Burr res

        Sidphat of lime

■ Jt{    | Arithilous Sulpluit of Alumine

  xjfr  8 Sulphat of Ahuninc
Sulpluit of Alumine
         with excess or base.
AX— I Sulpluitof Melanesia

AT"! 1 Sulphat of Silver
 A
 I o \  I Sulphat of Memory

fi\r~\ I Sulphat of Tin

/$\.^. I Sulphat of Copper
 ©n.
Arv
 ©EL
Mr
Sulphat of Lead

Sulphat of Iron

. lulphat of Zitdc

Sulphat of Mmaancse

Sulphat of JVictel
AR
PEr
AM
Ana


Sulphat of Antimony

Sulphat of Cobalt

Sulphat of Arsenic

Sulphat of Molybdena

Sulphat of 2una.rten

Succinat of Potash.

Arsauat of Potash

Acidulous Arse niat of Potash
Arscniat of Jbtash
        with excess of base.
       Motyhiha ot'Soda

/\  | Tungstnt of Ammonia

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