A
■^T*:
1<     -*
 
fok
Surgeon General's Offica
£I1M1M¥<
AMNuut.

&---^---v><"-<' OUQv, ^GOOOCKfO QUO j£* 
 
 
 
6 
 
 
ELEMENTS
OF
CHEMISTRY,
       BY M. I.  A. CHAPTAL,
EORMERLY CHEVALIER OF THE ORDER OF THE KING, PROFESSOR
   OF CHEMISTRY AT MONTPELLIER, HONORARY INSPECTOR
     OF THE MINES OF FRANCE, MINISTER OF THK IN-
       TERIOR, AND MEMBER OF SEVERAL ACADE-
          MIES OF SCIENCES, MEDICINE, AGRI.
            CULTURE, INSCRIPTIONS, AND
                 BELLES LE1TRES.
The fourth American Edition, ivith great additions and improvements,
       BY JAMES WOODHOUSE, M. D.
PROFESSOR OF CHEMISTRY IN THE UNIVERSITY OF PENNSYLVANIA, fee.

                 ---------—------;  ^           v>»
vol.i.         Ao,sty:\
   11                 >«"')
PHILADELPHIA.
     PUBLISHED BY BENJAMIN 8c THOMAS KITE,
              NO. 20, NORTH THIRD STREET.
HOLD ALSO BY THOMAS DOBSON, AND B B. HOPKINS & Co. PHILADELPHIA
   HENRY  CUSHING, PROVIDENCE ;  NATHANIEL DEARBORNE, NEW-
     PORT ; BEERS & HOW, NEW-HAVEN : SAMUEL WOOD, NEW-
        YORK ; DAVID ALLINSON, BURLINGTON ; ANDZADOK
                  CRAMER, PITTSBURGH.
1807.
BARTRAM & RF.YNOLD3, PRINTERS. 
            District  of Pennsylvania,  to   wit:

  BE IT REMEMBERED, that on the twenty-seventh day of October, in the thiry-first
year of the Independence of the United States of America, A. D. 1807,  Benjamin and
Thorna:- Kite of the said District have deposited in this  office the Title of a Book the right
whereof they claim as proprietors in the words following,  to wit:

    " Elements of Chemistry, by M. I. A. Chaptal, formerly Chevalier of the Order of
  " the King, Professor of Chemistry at Montpellier, honorary  Inspector of the Mines of
  " France, Minister of the Interior, and Member of several Academies of Sciences, Me-
  " dicine, Agriculture, Inscriptions, and Belles Lettres.  The fourth American Edition,
  " with great additions aud improvements, by James Woodhouse, M. D. Professor of
  " Chemistry in the University of Pennsylvania, &c."

  In conformity to the Act of the Congress of the United  States,  intituled " An Act for
the encouragement of learning, by securing the copies of Maps, Charts, and Books to the
authrrs and proprietors of such copies during the times therein mentioned." And also t«
the Act ent  led  ■ An act supplementary to the act entitled "An  act for the encourage-
mei i or learning by securing  the copies of Maps, Charts, and Books to the authors and
proprietors of br.ch copies during the times thetein mentioned," and extending the benefits
thereof to the Arts oi designing, engraving, and etching, historical and other prints."
                                                              D.  CALDWELL,
                                                              Clerk of the District
                                                              of Penmylvania. 
ADVERTISEMEN1  OF  THE AUTHOR.
      AGRICULTURE is  no doubt  the basis  of public
       welfare, because  it alone supplies  all the wants
which nature has connected with our existence.   But the
arts and commerce form the glory, the ornament, and the
riches of every polished nation; since our refinement, and
mutual dependance on each other, have created a new set
of wants which require to be supplied.   The cultivation
of the arts is  therefore become almost as necessary as
that of the ground;  and the true means of securing these
two foundations of the reputation and prosperity of a state,
consist  in  encouraging the Science of Chemistry, which
discovers their principles.   If this truth were not univer-
sally acknowledged,  I might on the present occasion give
an  account of the success with which my labours have
been attended in this province*.   I might even call  upon
the public voice; and it would  declare that,  since the
establishment of lectures on chemistry, between  three and
four hundred persons have every  year derived advantage
from instructions in this science.  It  is well  known that
our ancient schools of medicine and surgery,  whose suc-
cess and splendour are connected with the general interest
of this province, are more flourishing and more numerous
since that period.  And with the same confidence I might
appeal to the Public, that our manufactures are daily in-
creasing  in perfection; that several new kinds  of indus-
try have  been  introduced into Languedoc;  that, in  a re-
gular succession, abuses have  been  reformed in the ma-
nufactories, while the processes of the arts have been sim-
plified ; that  the number of coal-mines actually wrought
is increased;  and that upon my principles,  and in conse-
quence of my care and attention,  manufactories of alum,
* Languedoc 
IV
ADVERTISEMENT
of oil of vitriol, of copperas, of brown red, of artificial
pozzolana, of ceruse, of  white lead, and  others,  have
been established in several parts of the province.

  Chemistry is therefore essentially  connected with the
reputation  and prosperity of a state ;  and at this peculiar
instant,  when the minds of men are universally busied in
securing the public welfare, every citizen is accountable to
his country  for all the good which his peculiar situation
permits him to do.   Every one ought to hasten, and pre-
sent to society the tribute of those talents which  heaven
has bestowed on him; and there is  no  one who is not able
to bring some  materials, and deposite them at the foot of
the superb edifice which the virtuous administrators are
raising  for the welfare of the whole.   It is  with  these
views  that  I have presumed  to offer to my countrymen
the work which I at present  publish; and  I entreat  them
to exercise their severity upon the intention of the author
only,  but to reserve all their indulgence to the work.

   I publish these Elements of Chemistry with the greater
confidence, because  I have  had opportunities myself of
observing  the  numerous applications of  the  principles
which constitute its basis to the  phenomena of nature
and art.   The immense establishment of chemical pro-
ducts which I have  formed at Montpellier, has allowed
me to pursue  the  development of this  doctrine,  and to
observe its agreement with  all the facts which the vari-
ous operations present  to us.    It is this doctrine  alone
which has led me to simplify most of the processes, to bring
some  of them to perfection, and to rectify  all my ideas.
It  is  therefore with  the  most intimate confidence that
I propose  it. ' I find  no difficulty  in  making a public
acknowledgment that  I  have  for some time taught  a
different doctrine  from  that which  I  at  present  offer.
I  then believed  it to  be  true  and  solid; but I did
not on  that  account cease to consult nature.     I  have
constantly  entered into this  research with a mind eager
for  improvement.   Natural truths were capable of fixing
themselves with all  their  purity in my mind,  because I
had banished prejudice;  and  insensibly I found myself
drawn by  the force of facts  to the doctrine I now teach. 
OF  THE  AUTHOR,
V
Let  other  principles  impress  the  same  conviction  on
my mind;  let the same number of  phenomena and facts
exhibit  themselves in their favour; the same  number of
happy applications to the operations of nature and  of art;
let  them appear to my mind with all the sacred  charac-
ters of truth;  and I will publish them with the same zeal
and with the same interest.   I condemn equally the man
who,  attached to the  ancient notions,  respects them so
much as to reject without mature examination every thing
which appears to  oppose them ;  and him who embraces
with enthusiasm, and almost without  reflection, the prin-
ciples of any  new doctrine.    Both are worthy of com-
passion  if they grow old in their prejudices; and both are
worthy  of blame if they perpetuate them.

   I have been careful to  banish all discussions from  my
work.   That spirit of party which  but too often causes a
division between persons who are pursuing the same  ob-
jects, that tone of bitterness which predominates in cer-
tain disputes, that  want of candour which is insensibly
produced by the movements of self-love, have but too long
retarded the progress of  our knowledge.    The  love of
truth is the only passion which a philosopher  ought to in-
dulge.   The  same  object,  the same interest,  tend to
unite chemists.   Let the same  spirit inspire them, and
direct all their labours.   Then we shall soon behold che-
mistry advancing in a rapid progress; and its cultivators
will be  honoured  with the suffrage  and the gratitude of
their countrymen.

   I have endeavoured in this work  to exphiin my ideas
with clearness, precision, and method.  I know by expe-
rience that the  success of any work, and its various de-
grees of utility, often depend on the form  under which
the doctrine which it contains is displayed;  and it has  ac-
cordingly been my intention to spare no pains in exhibiting
the truths  which form the basis  of  this  work in all  the
characters they are justly entitled to.

   In composing these Elements  of  Chemistry,  I have
availed  myself with  advantage of all the facts which I
have  found in the works of the celebrated chemists who 
ADVERTISEMENT
 adorn this age.    I have  even made no scruple to follow
 their method in drawing up certain  articles; and have
 transferred into my own  work, almost without alteration,
 those facts which I have elsewhere found described with a
 greater degree  of precision and perspicuity  than  I might
 have been capable of bestowing on them.   This proceed-
 ing, in my opinion, renders homage to authors instead of
 robbing them.   If such  a proceeding might  justify re-
 clamations,  Messrs.  Lavoisier,  De Morveau,  Berthollet,
 De  Fourofoy,  Sage, Kirwan, &c. might easily  declare
 against me.

   I was well aware  that  the pretension of knowing, dis-
 cussing  and methodically distributing the whole of our
 present science of chemistry, was  an enterprise  beyond
 my ability.  This science has made so great a progress, and
 its applications  are so multiplied, that it is impossible  to
 attend to the whole with the same care : and it appears to
 me that the writer of an elementary work ought at present
 to attend principally to the elevelopment of general princi-
 ples, and content himself in pointing out the consequences,
 and their applications.    In  this way of proceeding we
 shall follow the method which has long been practised in
 the  study of the mathematics; the principles  of which,
 nearly insulated,  and separated from all application, form
 the first study of him who means to acquire them.

   To obtain a thorough acquaintance  with all  the know-
 ledge which has been acquired in chemistry until our time,
 the  chemical part of the  Encyclopedic Methodique may
 be consulted.   In this work, the celebrated author gives
 the most interesting account of the progress of the  science.
 Here it is that he discusses the several opinions with that
 candour  and energy  which  become  the  man of letters
 whose mind is directed to truth only.   Here it is that he
has made a precious eleposite  of all the knowledge yet ac-
 quired, in order  to  present  to us  in the same point  of
 view all which has been done, and all which remains to be
 done :  and here,  in a word,  it is that Mr.  De Morveau
 has rendered  the most striking homage to the truth of the
 doctrine  we now teach ;  because, after having combated
 some of its principles in the  first volume, he has had the 
OF  THE  AUTHOR.
Vll
courage to recant the moment the facts seen in a better
point of view, and repeated experiments, had sufficiently
enlightened  him.   This  great  example of courage and
candour  is doubtless honourable to the learned man who
gives it;  but it  cannot fail to add still more to the con-
fidence which may be placed in the doctrine which is its
object.

  The  development  of the  principles upon  which  the
New Nomenclature is  established, may be found in the
Elementary  Treatise of Chemistry of Mr.  Lavoisier;
and I  refer likewise  to this excellent work for the figure
and explanation of all the apparatus I shall have occasion
to speak of.   I take this step the more earnestly, because,
by  associating my own productions to those of this cele-
brated chemist, I entertain the hope of  securing their suc-
cess, and can deliver them into the hands  of the public
with the greater confidence. 
 
CONTENTS.
                   PART  FIRST.


     CONCERNING  THE  CHEMICAL  PRINCIPLES.

                 INTRODUCTION.
                                                   DPage.
    EFINITION of Chemistry ;  its Object and Means.—
  Description of a Laboratory, and the principal Instruments
  employed in chemical Operations, with a Definition of those
  Operations                                           29

                      SECTION  I.

Concerning the General Law which tends to bring the Particles
  of Bodies together, and to maintain them in a State of Mixture
  or Combination         -          -  .
Of the Affinity of Aggregation
Of the Affinity of Composition

                      SECTION  II.

Concerning the various Means employed by Chemists to over-
  come the Adhesion  which  exists between the  Particles of
  Bodies            -                                  54

                      SECTION III.

Concerning the Method of Proceeding which the Chemist ought
  to follow in the Study of the various Bodies presented to us
  by Nature                                            57

                      SECTION IV.

        Concerning Simple or Elementary Substances
Chap.  I.  Concerning Fire
  Art. I.   Concerning Caloric and Heat
  Art. II.  Concerning Light
Chap.  II.  Concerning Sulphur
Chap.  III.  Concerning Carbone

                      SECTION  V.

Concerning Gases, or the Solution of certain Principles in Caloric
  at the Temperature of the Atmosphere          -         90
     Vol. I.                 b
42
43
45
     64
     65
     66
     78
     84
5    88 
x                    CONTENT S,

Chap.  I.  Concerning the Hydrogenous Gas, or Inflam-     Page*
  mable Air             -             -           -         93
Chap.  II.  Concerning Oxigenous Gas, or Vital Air          ^^
Chap.  III.  Concerning Nitrogene Gas, Azote, or Atmosphe-
  rical  Mephitis           -             -        -         H*

                       SECTION  VI.

Concerning the Mixture of Nitrogene and Oxigene Gas ; or of
  Atmospheric Air            -             -              116

                      SECTION VII.

Concerning the Combination of Oxigenous Gas and Hydrogene,
  which forms Water             -           -             118
     Art. I.  Concerning Water in the State of Ice            120
     Ait II.   Concerning V* ater in the Liquid State          122
     Art. III.   Concerning Water in the State of Gas         125

                      SECTION VIII.

Concerning the Combinations of Nitroeene Gas.  1.  With Hy-
  drogene  Gas. 2. With the Earthy Principles forming the
  Alkalis             -           -           -             130
  Chap. I.  Concerning Fixed Alkalis           -            131
     Art. I.  Concerning the Vegetable Alkali, or Potash     ibid.
     Art. II.   Concerning the Mineral Alkali, or Soda        134
  Chap. II.  Concerning Ammoniac, or the Volatile Alkali    138

                       SECTION  IX.

Concerning the Combination of Oxigene  with  certain Bases
  forming Acids            -              -         -      142
   Chap. I.  Concerning the Carbonic Acid                  146
     Art. I.  Carbonate of Potash           -       -         152
     Art. II.  Carbonate of Soda              -              15"
     Art. III.  Carbonate of Ammoniac      -       -       154
   Chap. II.  Concerning the Sulphuric Acid                  156
     Art. I.  Sulphate of Potash       -          -          j6i
     Art. II.   Sulphate of Soda      -                      162
     Art. III.  Sulphate of Ammoniac      -         -      I64
   Chap. HI*   Concerning the Nitric Acid       -      -     i66
     Art. I.   Nitrate of Potash       -      -      .        i72
     Art. II.   Nitrate of Soda            -           .     j^g
     Art. III.  Nitrate of  Ammoniac     -           -     j^jj
   Chap. IV".   Concerning the Muriatic Acid        -        179
     Art. I   Muriate of Potash          -        .        j gQ
     Art.  II.   Muriate of Soda       -           .           19l
     Art  III.   Muriate of Ammoniac       -          .    195
 Concerning Oxide of Carbone         -          .          l55
 Ox.imuriate of Potash           .           .               l87 
CONTENTS.
XI
Chap. V.   Concerning the Nitro-muriatic Acid
Chap. VI.  Concerning the Acid of Borax
  Art. I.   Borate of Potash
  Art. II.  Borate of Soda
  Art. III.  Borate of Ammoniac
                     PART  SECOND.


    CONCERNING  LITHOLOGY;  OR AN  ACCOUNT  OF
                    STONY  SUBSTANCES.

 Introduction           -           -            -       207
 Lime          -             -             -              211
 Barytes, or Ponderous Earth         -         -        -    213
 Magnesia, or Magnesian Earth      -             -         212
 Alumine, or Pure Clay           -      -           .       215
 Silex, or Quartzose Earth,  Verifiable Earth, &c.        -    216
 Strontites             -            -         -             214
 Zirconia        -         -         -           .-           217
 Glucina        -             -                           ibid.
 Vttria        -                                           216
 Agustina          -      -            -          .         218

                         CLASS  I.

 Concerning the Combination of Earths with Acids     -       217

                          GENUS i.

                 Earthy Salts with Basis of Lime           -218
 Spec. 1.  Carbonate of Lime, or Calcareous Stone    -      219
 Crystallized Calcareous Stones       -             -         220
 Calcareous Stones which are not crystallized           -      221
 The Analysis and Uses of Calcareous Stone       -          226
 Spec. II. Sulphate of Lime, Gypsum, Selenite, Plaster Stone  230
 Spec. III. Fluate of Lime, Vitreous Spar, Fusible or Phosphoric
  Spar, Fluor Spar           -          -        -        234
 Spec. IV.  Nitrate of Lime, Calcareous Nitre         -      237
 Spec. V.  Muriate of Lime, Calcareous Marine Salt    -     238
 Spec. VI.  Phosphate of Lime, Calcareous Phosphoric Salt   ibid.

                        GENUS  II.
             Earthy  Salts with Base of Barytes       -       239
 Spec. I.  Sulphate of Barytes,  Ponderous Spar       -        ibid.
Spec. II   Carbonate of Barytes          -          -       241
Spec. III.  Nitrate of Barytes           -             -     242
Spec. IV.  Muriate of Barytes          -           -       ibid.
Page.
  197
  199
  202
 ibid.
  206 
xii
CONTENTS.
Page.
                        GENUS III.

               Earthy Salts with Basis of Magnesia
Spec. I.  Sulphate of Magnesia, Epsom Salt
Spec. II.  Nitrate of Magnesia
Spec. III.  Muriate of Magnesia
Spec. IV.  Carbonate of Magnesia

                        GENUS IV.

           Earthy Salts with Base of Alumine, Alum         246
Spec. I.  Sulphate of Alumine,  Alum           •          ibid-
Spec. II.  Carbonate of  Alumine           -         -      249

                         GENUS V.

               Earthy Salts with Base of Silex      -       250
                        CLASS  II.

Concerning the Combination and Mixture of Primitive Earths,
  or Earthy Mixtures         -        -           -        250

                         GENUS  I.

                   Calcareous Mixtures
Spec. I.  Lime-stone and Magnesia
Spec. II.  Lime-stone and Barytes
Spec. III.  Carbonate of Lime and Alumine
Spec. IV.  Lime-stone and Silex
Spec. V.  Lime-stone and Bitumen
Spec. VI.  Lime-stone and Iron


                         GENUS  II.

                      Barytic Mixtures      -      -      254
Spec- I-  Sulphate of Barytes, Petroleum, Gypsum, Alum, and
  Silex—Bergmanni Sciagr. s. 90 ; Kirwan Min.  p. 60       255
Spec. II.  Carbonate of Barytes, Iron and Silex      -      ibid.

                        GENUS III.

                       Magnesian Mixtures        -      255
Spec. I.  Pure Magnesia, Silex, and Alumine        -      256
Spec. II.  Carbonate of Magnesia, Silex, an,d Alumine      ibi4.
 242
 243
 244
ibid.
 245
 251
ibid.
 252
ibid.
 253
ibid.
 254 
CONTENTS.
xm
                                                        Page.
Spec. III. Pure Magnesia combined with somewhat more than
  its Weight of Silex, one-third of Alumine, near one-third of
  Water, and more or less of Iron        -           -      258
Spec. IV.  Carbonate of Magnesia;  Silex, Lime,  Alumine
    and Iron             -           -                     259
Variety I. Asbestos           -         -          -       260
Variety II.   Mountain Cork           -         -          ibid.
Spec. V.  Carbonate of Magnesia and Lime, Sulphate of Bary-
  tes, Alumine and Iron           -        -        -      261
                         GENUS IV.

                    Aluminous Mixtures       -       -   •   262
Spec. I.  Alumine, Silex, Carbonate of Lime and more or less
   of Iron      ......      ibid.
Spec. II.  Alumine, Silex, Pure Magnesia,  and Iron         268
Spec. III.   Alumine, Silex, Magnesia, Lime, and Iron       269
Variety  I.   Black Horn-stone, Lapis Corneus Nitens Wallerii ibid.
Variety  II.   Horn-stone of a Greenish Grey Colour          270
Spec. IV.   Alumine, Silex,  Carbonate of  Magnesia, and of
   Lime with Iron       -                                  ibid.
Variety  I.   Blueish Purple Slate         -           -      ibid.
Variety  II.  Black Slate      -      -        -      -     271
Variety  III.  Blue Slate         -         -        -      ibid.
Variety  IV.  Slate of a Pale white Colour      -      -     272
Spec V. Alumine, Silex, Pyrites or  Sulphure of  Iron,  and
   Carbonate of Lime and of Magnesia        -       -      ibid.
Spec. VI.   Alumine, Silex, the Carbonates of  Lime and of
   Magnesia, the Sulphure of  Iron and Bitumen         -      273
Spec. VII.   Alumine, Silex, Lime, and Water       -       274

                         GENUS  V.

                  Siliceous Mixtures         -         -      275
Spec. I.  Silex, Alumine, L.ime, and Iron, intimately combined, ibid.
Division I.   Red Gems, or Precious Stones—the Ruby, Gar-
   net,  &c.       -      -       -         -       -         276
Division II.  Yellow  Gems or Precious  Stones—the  Topaz,
   the Hyacinth, &c.          -      -        -       -     277
Division  III. Green Gems—the Emerald, Chrysolite, Beryl, &c. 279
Division  IV.  Blue Gems—Sapphire         .         -       281
Spec. II. Silex, sometimes pure, but oftener mixed with a very
   small Quantity of Alumine, Lime, and Iron         -       282
Division  I.  Rock  Crystal           -          -           ibid.
Variety  I.   Red Crystal—False Ruby         -       -      284
Variety  II.  Yellow Crystal—Bohemian Topaz      -       285
Variety  III.  Brown  Crystal—Smoky Topaz        -       ibid.
Variety  IV.  Green  Crystal—False Emerald         -       ibid.
Variety  V.  Blue Crystal—Water Sapphire        -        ibid
/ 
:<iv
CONTENTS
                                                        Page.
Variety VI.  Violet  Crystal—the Amethyst        -        286
Division  II.  Quartz          -         -         -         ibid.
Spec. III. Silex, Alumine,  Lime, and Iron, intimately mixed 287
Division  I.  The Coarser Flints                  -          ibid.
Division  II.  The liner Flints        -                    288
Spec. IV. Silex, Alumine, and Iron           -      -      291
Spec. V.   Silex, Alumine, Lime, with a small Portion of Mag-
  nesia and Iron      -                      -            292
Spec. VI.  Silex, Lime, Magnesia,  Iron, Copper,  and the
  Fluoric Acid        -        -         -         "        30°
Spec. VII.  Silex, the Blue  Fluate of Lime, with the Sulphate
  of Lime or Iron        -     -       -       "■          303
Spec. VIII.  Silex,  Alumine, Barytes, and Magnesia        305
                        CLASS III.

Concerning the Mixture of Stones among each other.  Stony
   Mixtures.   Rocks        -               -              307

                          GENUS I.

Rocks formed by the Mixture of Calcareous Stones with other
   Species      -      -           -                        308
Spec.  I.  Carbonate of Lime,  and Sulphate of Barytes       ibid.
Spec.  II.   Carbonate of Lime and Mica       -         -     ibid.
Spec.  III.  Mixtures of Calcareous and Magnesian Stones    ibid.
Spec.  IV.  Calcareous Stones, and Fragments of Quartz      309

                         GENUS  II.

Compound Stones formed by the  Mixture of Barytic Stones
   with other Stones       -       -       -      -      -     309
Spec. I.   Ponderous Spar mixed with a small Quantity of Cal-
   careous Spar      -         -      -      -              31©
Spec.  II.   Ponderous Spar and Serpentine      -          ibid.
Spec. III.  Ponderous Spar and Fluor Spar      -          ibid.
Spec.  IV.  Ponderous Spar and Indurated Clay         -     ibid.
Spec. V.   Ponderous Spar and Quartz        -      -         311
Spec. VI.  Ponderous Spar and Lava        -       -       ibid.

                         GENUS III.

Rocks  or  Stones formed by the Mixture of Magnesian Stones
  with other Kinds        -        -          -           311
Spec. I.   Magnesian Stones mixed together      -       -     ibid.
.Spec. II.   Magnesian Stones and Calcareous  Stones          ibid.
Spec. III.  Magnesian Stones and Aluminous Stones          312
Spec. IV.  Magnesian Stones and Siliceous Stones            ibid. 
CONTENTS.
xv
                                                         Page.
                         GENUS  IV.

Rocks  or Stones formed by the Mixture of Aluminous Stones
  with other Species      ...       -             312
Spec. I.  Schistus and Mica      -                -        ibid.
Spec. II.   Schistus and Garnet        -         -      -    313
Spec. III. Schistus. Mica, and Quartz mixed in small Fragments ibid.
Spec. IV.  Schistus and Schorl        -       -      -      314
Spec. V.   Clay and Quartz       -                          ibid.

                         GENUS  V.

Compound Stones formed by the Mixture and of Re-union of
  Quartzose Stones with each other       -      -      -    315
Spec. I.   Quartz and Schorl      -                         ibid.
Spec. II.   Quartz and Feld Spar       -         -      -     316
Spec. III.  Grit-stone and Garnet      -                    ibid.
Spec. IV.  Quartz, Feld Spar, and Schorl       -       .     ibid.
Spec. V.   Fragments of Quartz united by a Siliceous Cement 317
Spec. VI.  Jasper and Feld Spar      -                    ibid.
Spec. VII.  Jasper and Garnet        -       -      -      318
Spec. VIII.   Jasper and Calcedony       -                   ibid.
Spec. IX.  Jasper and Quartz      .      -           -     319
Spec.  X.  Jasper, Quartz, and Feld Spar       -       -     ibid.
Spec.  XI.  Schorl, Garnet, and Tourmaline        -         ibid.

                         GENUS  VI.

Super-compound Stones, or such as result from the Mixture
   and Re-union of several different Genera         -        320
Spec. I.  Petrosilex, Alumine, and Calcareous Spar    -    ibid
Spec. II.  Clay,  Steatites, and Calcareous Spar       -       ibid.
Spec.  III.  Clay, Zeolite, Schorl, and Calcareous Spar       ibid.
Spec IV.  Clay, Serpentine, and Calcareous Spar           ibid.
Spec. V.  Serpentine, Mica, and Calcareous Spar     -      ibid.
Spec.  VI.  Serpentine, Schorl,  and Calcareous Stone        321
Spec. VII.   Steatites, Mica, and Garnets       -       -     ibid.
Spec. VIII.   Steatites, Mica, and Schorl       -      -     ibid.
Spec. IX.   Garnets,  Quartz,  Mica, and Serpentine          ibid,
Spec X.  Feld Spar, Quartz, Mica, Steatites       -       ibid.
Spec. XI.  Quartz,  Mica, and Clay         -      -        ibid.
Spec. XII.  Quartz,  Clay, and Steatites       -       -       322
Concerning the Diamond         ....    ibid.

General Views respecting the Decompositions and Changes to which
  the Stony Part of our Globe has been Subjected.       -      326 
 
#
PRELIMINARY DISCOURSE.
   IT appeals that the ancient nations possessed some no-
    tions of chemistry.  The art of working metals, which
<dates from the most remote antiquity; the lustre which the
 Phoenicians gave to certain colours;  the luxury of Tyre;
 the  numerous manufactures which  that opulent city in-
 cluded within its walls—all announce a degree of perfec-
 tion in the arts, and suppose a considerable extent and va-
 riety of chemical knowledge.   But the principles of this
 science were not then united into a body of doctrine; they
 were concentrated in the workshops of the manufactures,
 where they had their origin: and observations alone, trans-
 mitted from one operator to another,  enlightened and con-
 ducted the steps of the artists.  Such, no doubt, has been
 the origin of all the sciences.  At: fir->t they presented un-
 connected facts; truths were confounded with error; time
 and genius alone could clear up the  confusion;  and the
 progress of information is always the  fruit of slow and
 painful experiment.   It is difficult to point out the precise
 epocha of the origin  of chemical science;  but we find
 traces of its existence in the most remote ages.  Agricul-
 ture, mineralogy, and all the arts which are indebted to it
 for their principles, were cultivated and enlightened. We
 behold the original nations,  immediately succeeding the
 fabulous ages, surrounded by all the arts which supplied
 their wants;  and we  may compare chemistry to that fa-
 mous river whose waters fertilize the lands they inundate,
 but whose  sources are still to us unknown.
   Egypt, which appears to have been the nurse of che^
 mistry reduced to principles, was not slow in turning the
                           A 
PRELIMINARY DISCOURSE,
»
applications of this science towards a chimerical end.  The
first seeds of chemistry were soon changed by the passion
of making gold.   In a moment all the labours of opera-
tors were directed towards alchemy alone ;  the great ob-
ject of  study  became fixed on an endeavour to interpret
fables, allusions, hieroglyphics, &c.;  and. the industry of
several centuries was consecrated to the inquiry after the
philosopher's stone.  But though we admit that the alche-
mists have retarded the progress of chemistry, we are very
far from being disposed to any outrage on the memory of
these  philosophers: we allow them the tribute of esteem
to which on so many accounts they are entitled. The pu-
rity of their sentiments, the simplicity of their manners,
their submission to Providence, and their love for the Cre-
ator, penetrate with veneration all those  who read  their
works.  The profoundest views of genius are every where
seen in  their writings, allied with the most extravagant
ideas.   The most sublime truths are degraded by appli-
cations  of the most ridiculous nature; and this astonish-
ing contrast of superstition  and philosophy, of light and
darkness,  compels us to admire them, even at the instant
that we cannot withhold our censure.  We must not con-
found the sect of alchemists, of whom we shall proceed to
speak, with that crowd of impostors, that sordid multitude
of operators at the furnace, whose researches were  direct-
ed to the discovery of minds capable of being imposed up-
on, who fed the ambition of such weak minds by the de-
ceitful hope of increasing  their riches.  This last class of
vile and ignorant  men has never been acknowledged by
the true alchemists; and they are no more entitled to that
name, than the vender of  specifics on the stage to the ho-
nourable name of Physician.
   The  hope of the alchemist may indeed be founded on a
slender  basis;  but the great  man, the man of genius, even
at the  time when he  is  pursuing  an imaginary object,
knows how to profit by  the phenomena which may pre-
sent themselves,  and derives from his labours many use-
ful truths which would  have escaped  the penetration of
ordinary men.   Thus it is that the alchemists have suc-
cessively enriched pharmacy and the arts with most of their
compositions.   The strong desire of acquiring riches has
in all times been a passion so general, that this single mo- 
PRELIMINARY DISCOURSE.
,J5
live has been sufficient to lead many persons to the culti-
vation of a science which has more relation than any other
to metals;  which  studies their nature more particularly,
and appears to facilitate the means of composing them.
It is known that the Abdarites did not begin to consider the
sciences as an occupation worthy a reasonable man, until
they had seen a celebrated philosopher enrich himself by
speculations  of commerce ;  and  I do not doubt but that
the desire of making gold has decided the vocation of se-
veral chemists.  We  are therefore indebted to alchemy
for several truths,  and for several chemical professors: but
this  obligation is small in comparison to the mass of use-
ful truth which might have been afforded during the course
of several centuries;   it. instead of endeavouring to form
the metals, the operations of chemists had been confined
to analizing them,  simplifying the means of extracting
them,  combining them  together,  working them,  and
multiplying and rectifying their uses.
   The rage for making gold was succeeded by the seduc-
 tive hope of prolonging life by means of chemistry.   The
 persuasion was easily admitted, that  a science which af-
 fords remedies for all disorders, might without effort sue-
 ceed in  affording a universal medicine.   The relations
 which  have been handed down to us of the long life of
 the  ancients, appeared to be a natural effect of their know-
 ledge in  chemistry.   The numerous fables of antiquity
 obtained the favour of being admitted among established
 facts; and  the alchemists, after having exhausted them-
 selves in the search after the philosopher's stone, appear-
 ed to redouble their efforts to arrive at an object still more
 chimerical.  At this period the elixirs of life, the arcana,
 the  polychrest medicines, had their origin;  together with
 all those monstrous preparations, of which a few have been
 handed down even to our days.
   The  chimera  of  the  universal medicine agitated the
 minds of most men in the sixteenth century;  and immor-
 tality was then promised with the same effrontery as a
 Charlatan now announces his  remedy for every disease.
 The people are  easily seduced  by  these ridiculous pro-
 mises;  but the man of knowledge can  never be led  to
 think that chemistry can succeed in reversing that gene
 ral  law of nature which condemns all living beings to re* 
4            PRELIMINARY DISCOURSE.
novation, and a continual circulation  of decompositions
and successive generations.  This seci gradually became
an ohj xt of contempt.   The enthusiast Paracelsus, who,
after having flattered himself with immortality, died at the
age of forty-eight  at an inn at  Saltsburg, completed its
diso-race.   From that moment the  scattered remains of
this sect united themselves, nevermore to appear again in
public.  The iight which began to shine forth on all sides,
rendered it necessary  that they should have recourse to
secrecy and obscurity;   and thus at length chemistry be-
come purified.
  Jam 23 Earner, Bchnius,  Tachenius,  Kunckel, Boyle,
Croliius, Gkser, Glauber, Schroder, &c. appeared on the
ruins of rhese  two sects, to examine this indigested ag-
gregate, a; id separate from  the confused mass of pheno-
mena, of truth and of error, every thing which could tend
to enhghten the science.   The sect of the adepts, urged on
by the madness of immortality, had discovered many re-
medies ; and pharmacy and the arts then became enriched
with  formulae  and compositions, whose  operations re-
quired only to  be rectified, and their applications better
estimated.
  Nearly at the same  time appeared the  celebrated Be-
cher.  He  withdrew chemistry from the too narrow limits
of pharmacy.   He shewed its connexion with all the phe-
nomena of nature; and the theory of the formation of me-
tals,  the phenomena of fermentation, the laws of putrefac-
tion, were  all comprehended and  developed by this supe-
rior genius.  Chemistry was then directed to its true ob-
ject:  and Stahl, who succeeded Becher, reduced  to  cer-
tain general principles all the facts with which his prede-
cessor had enriched the science.   He  spoke  a language
less enigmatical; he classed all  the facts  with order and
method; and purged the science of that alchemic infec-
tion, to which Becher  himself was too much attached.
But if we consider how great are  the claims of Stahl, and
how few the additions which have been made to his doc-
trine until the middle of this century, we cannot but be
astonished  at the small progress  of the science.  When
we consult the labours of the chemists who have appeared
since the time of Stahl, we see most of them chained down
to the steps of this great man, blindly subscribing to all 
PRELIMINARY DISCOURSE.            5
his ideas; and the labour of thinking appeared no longer
to exist among them.  Whenever a well-made experiment
threw a gieam of light  unfavourable to his doctrine, we
see them torment themselves in  a ridiculous  manner to
fonn a delusive interpretation.  Thus it was that the in-
crease  of  weight which metals  acquire by  calcination,
though little iltvouKibie  to the idea of the subtraction of
a principle without any  other addition,  was nevertheless
incapable of injuring this doctrine.
  The almost religious opinion which  enslaved all the
chemists to Stahl, has no doubt been pernicious to the
progress of chemistry.   But the  strong  desire of re-
ducing every tiling to  first principles,  and of establish-
ing a theory upon incomplete experiments, or facts im-
perfectly seen,  did not  admit of the smallest obstacles.
From  the moment that  analysis had  shewn  some of the
principles of bodies, the chemist thought himself in pos-
session of the first agents of nature.  He considered him-
self as authorized to regard those  bodies  as elements
which appeared no longer susceptible of being decom-
posed.   The acids and the alkalis performed the principal
part in natural operations;  and it appeared to be a truth
buried in  oblivion, that the term where the  artist stops
is not the point at which the Creator has limited his pow-
er;  and  that  the last result of  analysis  does indeed
mark the limits of art,  but does not fix those of nature.
We might likewise reproach certain chemists for having
too long neglected the operations of the living systems.
The}- confined themselves in their laboratories, studied
no bodies but in their lifeless state,  and were incapable
of  acquiring any knowledge but such as was very in-
complete :  for he  who,  in his researches,  has no  other
object in  view than that of ascertaining the principles
of a substance, acts like a physician  who should suppose
he had acquired a complete notion of the human  body
by confining his studies to the  dead carcass.  But we
must likewise observe that, in order to form a proper no-
tion of the phenomena of living bodies, it  is necessary
to possess the means of confining the gaseous principles
which escape from bodies;  and of analizing  these vola-
tile  and invisible  substances which combine together.
Now this  work was impossible at  that time;  and we 
6-             PRELIMINARY  DISCOURSE.
ought to beware of imputing to men those errors which
arise from the state of the times in which they lived.
   It may perhaps be  demanded, on  this  occasion,  why
chemistry was sooner known,  and more generally culti-
vated, in Germanv and in the North  than in our  king-
dom.   I  think that many reasons may be given for this.
In the first place, the scholars of Stahl and of Becher must
have been more numerous,  and consequently  their  in-
struction farther extended.   Secondly,  the  working of
mines having become  a resource necessary to the  go-
vernments of the North, has been singularly encouraged;
and that chemistry which enlightens mineralogy must ne-
cessarily have participated in its encouragements*.
   The study of chemistry did not  begin to be cultivated
to advantage  in France until the end of  the last century.
The first wars of Louis XIV. so proper  to  develop  the
talents  of the artist,  the historian, and the military man,
appeared little favourable to  the peaceable  study of  na-
ture.   The  naturalist,  who  in  his researches sees union
and  harmony around him, cannot be an indifferent spec-
tator  of the continual  scenes of  disorder and destruction;
and his genius is crushed in the midst  of troubles  and
agitations.   The mind  of the great  Colbert,  deeply  pe-
netrated with these truths, quickly endeavoured to  tem-
per the fire of discord, by turning the minds of men to-
wards the only objects which could secure the peace and

   * Since the French government has facilitated the study of mi-
neralogy by the most superb establishments, we have  beheld the
taste for chemistry revive, the arts which have the working of me-
tals for their object have  been rendered more perfect, and the mines
which have been wrought are more numerous.   Mr. Sage has been
more particularly assiduous and zealous to  turn the favour of go-
vernment towards this object.  I  have been a witness to the  labo-
rious attention of this chemist to effect this revolution.  I have be-
held the  personal sacrifices he made to  bring it forward.  I have
applauded his zeal, his motives, and  his  talents. The same senti-
ments still occupy my  mind ; and  though I teach a  doctrine at
present which is different from his, this circumstance arises from
the impossibility of commanding opinions.   The philosopher  who
is truly worthy of this name, is capable of distinguishing the friend
of his heart from the slave of his system :  and, in a word, every
one ought to write according to his conviction ;  the most sacred ax-
iom of the sciences being " Amicus  Plato, sed magis amrca Veri-
tas.'? 
PRELIMINARY DISCOURSE.
f
prosperity of the state.  He exerted himself to render
trade flourishing : he established manufactories : learned
men were invited from all parts, encouraged, and united
together, to promote his vast projects.   Then it was that
die ardour of inquiry replaced for a time the fury of con-
quest ; and  France very soon  stood in competition with
all nations for the rapid progress of the  sciences, and the
perfection of the arts.  Lemery,  Homberg,  and Geof-
froy arose nearly at the  same  time; and other nations
were no longer entitled to  reproach us for the want  of
chemists.   From that moment  the  existence of the  arts
appeared  to be well assured.   All the sciences which af-
ford their first principles, were cultivated with the greatest
success:  and  it will scarcely  be  credited that, in the
space of a few years, the  arts were drawn from a state
of non-entity;  and carried  to  such a degree of perfec-
tion, that France, which had before received every thing
from foreign countries, became in possession of the glory
of  supplying its neighbours with models  and with mer-
chandises.
   Chemistry and natural history, however, at the begin-
ning  of this century,  were cultivated  only by a  very
small number  of persons; and it was then thought that
the study of these  sciences ought to be confined to the
academies.  But two  men, whose names will be  ever
famous,  have  rendered the taste general  under the reign
of  Louis XV.  The one  possessed  that noble  spirit
which is a stranger to the power of prejudice, that inde-
fatigable ardour which so easily overcomes every obsta-
cle, that openness of character  which inspires confidence,
and transfused into the minds  of  his pupils that enthusi-
asm of which  he himself felt the force.  While Rouelle
enlightened the science of  chemistry, Buffon prepared a
revolution still  more astonishing in natural history.   The
naturalists of the North had succeeded  in causing  their
productions to  be read by a small number of the learned;
but the works  of the  French  naturalist were  soon, like
those of nature,  in the hands  of the whole world.   He
possessed the  art  of diffusing through his writings that
lively interest,  that enchanting colouring, and that  deli-
cate and  vigorous touch,  which  influence,  attach, and
subdue the mind.  The profundity of his reasoning is 
 8             PRELIMINARY  DISCOURSE.

 every  where united to all that agreeable illusion which
 the most brilliant imagination  can' furnish.  The  sacred
 fire of trenius animates all his  productions ;  his systems
 constantly exhibit the most sublime prospects in their to-
 tality,  and die most perfect correspondence  in  their mi-
 nute parts:  and, even "when he  exhibits mere hypothe-
 ses,  we  are inclined  to  persuade ourselves that they are-
 established truths.  We become like the artist who, af-
 ter having admired  a beautiful statue, used his  efforts to
 persuade  himself that it respired,  and removed every
 thing which  could  dissipate his illusion.   We take up
 his work with a pleasure resembling that of the man who
 turns again to sleep, in hopes of prolonging the decep-
 tion of an agreeable dream.
   These two celebrated men,  by diffusing the taste for
chemistry and natural history,  by making their relations
 and uses better known, conciliated the favour of govern-
 ment towards them; raid from that moment every one
 interested himself in the progress of both sciences. Those
 persons who were best qualified in the kingdom, hastened
 to promote  the revolution which was  preparing.   The
 science's soon inscribed in their list of cultivators the be-
 loved and respected names of La Rochefoucault, Ayen,
 Chaulnes; Lauraguais, Malesherve,  &c.; and these men,
distinguished by their birth,  were honoured with a  new
 species of glory, which is independent of chance or pre-
judice.   They enriched chemistry with their discoveries,
and  associated their names with all the other literati who
pursued the same career.  They revived in  the mind of
the chemist that passion for glory, and that ardour for the
public good, which continually excite new efforts.   The
man of ambition and  intrigue no longer endeavoured to
depress the modest  and timid man of genius.  The  cre-
dit of men  in  place  served  as a  defence  and support
against calumny and persecution.   Recompenses  were
assigned  to  merit.  Learned men were despatched into
all parts  of the world,  to study the arts, and collect their
productions.   Men of the first merit were invited to in-
struct  us with regard to our own proper  riches;  and
establishments  of chemistry which  were made  in the
principal towns, of  the kingdom, diffused  the  taste  for
this science,  and fixed among us those arts which we 
PRELIMINARY DISCOURSE.
9
might in vain have attempted to naturalize, if a firm ba-
sis had not been first laid.  The professors established in
the capital, and in the provinces, appeared to be placed
between  the academies and  the people, to prepare the
latter for those truths which flow from  such respectable
associations.   We  may consider  them  as  a medium
which refracts and modifies the rays of light that issue
from those various luminous centres;  and directs them
towards the manufactories, to enlighten and improve their
practice.   Without these favours,  without this conside-
ration and these  recompenses,  could it have  been ex-
pected that the  most unassuming among philosophers
would have exerted himself to promote the reputation of
a people to whom he was unknown?  Could a man so si-
tuated reasonably hope to succeed  in carrying a  disco-
very into effect ? Is it probable that he  should have pos-
sessed a sufficient fortune to work in the large way, and
by this means alone to overcome the  numberless  preju-
dices which banish men of science from manufactories ?
The contemplative sciences demand of  the sovereign re-
pose and liberty only;  but experimental sciences demand
more, for  they  require  assistance  and encouragement.
What indeed could be hoped  in those barbarous  ages,
wherein  the chemist  scarcely  durst  avow the nature of
the  occupation which  in secret constituted his greatest
pleasure.  The tide of Chemist was almost a reproach:
and  the prejudice which confounded the professors of this
science with such wretched projectors as are entitled only
to pity, has probably  kept back the  revival  of the arts
for   several centuries;  for chemistry alone can  afford
them a proper basis.  If the princes  of past  times had
been friends of the arts, and jealous to acquire  a pure
and  durable reputation; if they had been careful to ho-
nour the learned, to collect their valuable labours and to
transmit to us without alteration the precious annals of
human  genius;  we should have been dispensed from la-
bouring among the rubbish of early times, to consult a
few  of those remains  which have escaped the general
wreck; and we should have  been spared  the  regret of
allowing, after many useless researches, that the master-
pieces of  antiquity which remain  answer scarcely any
other purpose than to give us an idea of that superiority
                         B 
10
PRELIMINARY  DISCOURSE.
to which  the earlier  nations had arrived.   Time,  the
sword, fire, and prejudice have devoured all;  and our re-
searches serve only  to add to our regret for the  losses
which the world has sustained.
  The science of chemistry possesses the glory, in our
days, not only of having obtained the protection of govern-
ment, but it may likewise  boast of another equally  ele-
vated.   This science  has fixed the attention, and formed
the occupation,  of various men in whom  the habit of a
profound study of the accurate sciences  had produced a
necessity of admitting nothing but what is proved, and of
attaching themselves only to such branches of knowledge
as are susceptible of strict proofs.  Messrs. De la Grange,
Condorcet, Vander  Monde, Monge,  De la Place, Meus-
nier, Cousin, the most celebrated mathematicians of  Eu-
rope, are all  interested  in the progress of this science,
and most of them daily add to its progress by their disco-
veries.
   So great a mass of instruction, and such ample encou-
ragement, could not but effect a revolution in the science
itself;  and we are indebted to the combined efforts of all
these learned men for the discovery of several metals, the
creation of various  useful arts, the knowledge of a num-
ber of advantageous  processes, the  working of several
mines, the analysis of the gases, the decomposition of wa-
ter, the theory of heat, the doctrine  of combustion;  and
a mass of knowledge so absolute and so extended, respect-
ing all the phenomena of art and of nature, that in a very
short time chemistry has become a science entirely new.
We might now say with much more truth what the cele-
brated Bacon affirmed of the chemistry of his time:  "A
new philosophy," says he, "has issued from the furnaces
of the chemists, which has confounded all the reasonings
of the ancients."
   But while discoveries became  infinitely multiplied in
chemistry, the necessity of remedying the confusion which
had so long prevailed, was soon seen,  and indicated the
want of a reform in the language of this science.   There
is so intimate a relation between words and facts, that the
revolution which takes place in the principles of a science
ought to  be attended with a similar revolution in its lan-
guage : and  it  is no more possible to preserve a vitious 
                 PRELIMINARY  DISCOURSE.            11

   nomenclature with a science which becomes enlightened,
   extended, and simplified, than  to polish, civilize,  and in-
   struct uninformed man without making any change in his
   natural language.   Every chemist who Avrote on any sub-
   ject was  struck with the  inaccuracy of the words in com-
   mon use, and considered himself as authorized to intro,
   duce some change;  insomuch that the chemical language
   became insensibly longer, more  confused, and more un-
   pleasant.   Thus carbonic acid  has been known, during
4  the course of a few years, under the names of Fixed Air,
   Aerial Acid, Mephitic Acid, Cretaceous Acid,  &c.; and
   our posterity may hereafter dispute whether these various
   denominations were  not  applied to different substances.
   The time was therefore come,  in which it was  necessary
   to reform the language of chemistry;  the imperfections of
   the ancient nomenclature, and the discovery of many new
   substances, rendered this revolution indispensable.   But
   it was necessary to defend this  revolution  from the ca-
   price and fancy of a few individuals; it was necessary  to
   establish this new  language upon  invariable principles:
   and the only means of insuring this purpose was doubt-
   less that of erecting a tribunal  in which chemists of ac-
   knowledged merit should discuss the words received with-
   out prejudice and without interest;  in which the princi-
   ples of a  new nomenclature might be established and pu -
   rified by  the severest logic;   and in which  the language
   should be so well identified  with the science, the word so
   well applied to the fact, that the  knowledge of the  one
   should lead to the knowledge of the other.  This was ex-
   ecuted in 1788 by Messrs. De  Morveau, Lavoisier, Ber-
   thollet, and De Fourcroy.
     In order to establish a system of nomenclature, bodies
   must be considered in two different points of view, and
   distributed into two classes;  namely,  the class of simple
   substances reputed to be elementary, and the class of com-
   bined substances.
     1.  The most natural and  suitable denominations which
   can be assigned to simple substances, must  be deduced
   from a principal and characteristic property  of  the  sub-
   stance intended to be expressed.  They may likewise be
   distinguished by words which d© n«t present any precise 
12           PRELIMINARY DISCOURSE.

idea to the mind.   Most of the received names are estabr
lished on this last principle,  such as the names Sulphur,
Phosphorus, which do not convey any signification in our
language,  and produce  in our minds determinate ideas
only, because usagj has applied them to known substances.
These words, rendered sacred by  use,  ought to be pre-
served in a new nomenclature;  and no change ought to be
made, excepting when it is proposed to rectify vitious de-
nominations.   In this case the authors of the new nomen-
clature have thought it proper to deduce the denomination
from the principal characteristic property of the substance.
Thus, pure air might have  been called Vital Air, Fire
Air, or Oxigenous Gas; because it is the basis of acids,
and the aliment of respiration and  combustion.  But it
appears to me that this principle has been in a small de-
gree departed from  when the name of Azotic Gas was
given to the atmospherical mephitis—1. Because, none of
tne known gaseous  substances excepting vital air being
proper for respiration, the  word Azote agrees with every
one of them except one; and consequently this denomina-
tion is not  founded upon an exclusive property, distinc-
tive and characteristic of the gas itself.   2. This denomi-
nation being once introduced, the nitric acid ought to have
been called Azotic Acid, and its combinations Azotates;
because the acids are proposed to be denoted by the name
which belongs to their radical.   3. If the denomination of
Azotic Gas does not agree with this aeriform substance,
the name of Azote agrees still less with the  concrete and
fixed substance;  for in  this  state all the gases are essen-
tially azotes.  It appears to me therefore that the denomi-
nation of Azotic Gas is not established according to the
principles which have been adopted; and that the names
given to the  several  substances of which  this gas consti-
tutes one of  the  elements, are equally removed from the
principles of the nomenclature.   In order.to correct the
nomenclature on this head, nothing more is necessary than
to  substitute to this  word a denomination which is derived
from the general system made use of;  and I  have pre-
sumed to propose that  of Nitrogene  Gas.  In the first
place, it is deduced from the characteristic and exclusive
property of this  gas, which forms the radical of the  nitric
 acid.  By this means we  shall preserve to the  combing- 
PRELIMINARY DISCOURSE.
13
tions  of this substance the received denominations, such
as those of the Nitric Acid, Nitrates, Nitrites, &c.  In this
manner the word whi<fh is  afforded by  the  principles  a-
dopted by the celebrated authors of the Nomenclature,
causes every thing to return into  the order proposed to be
established.
  2.  The method made use  of to ascertain the denomi-
nations suitable to compound substances, appears to me
to be simple and accurate.   It has been thought that the
language of this part of science ought to present the ana-
lyses;  that the words should be only the expression of
facts;  and that consequently  the denomination applied by
a chemist to any substance which  has been analized,  ought
to render him acquainted with its constituent parts.  By
following this method, the nomenclature is as  it were
united, and  identified  with  the  science;  and facts and
words agree together.  Two things are therefore united,
which until this time appeared to have no mutual relation,
the word, and the substance which it represented; and by
this means the study of chemistry is simplified. But when
 we apply these incontestable principles  to the various ob-
jects of chemistry, we ought to follow the analysis step by
step, and on this ground alone establish general and indi-
vidual  denominations.   We ought to  observe that it is
from this analytical method that the various denomina-
 tions have been assigned, and that the methodical  distri-
 butions of natural history have been at all times made. If
 man were to open his eyes for  die first time upon the vari-
 ous beings which people or compose this globe, he would
 establish their relation upon the comparison of their most
 evident properties, and no doubt  would found his first di-
 visions upon the most sensible differences.   The various
 modes of  existence, or their several degrees of consist-
 ence, would form his first  division;  and he would arrange
 them under the heads of solid, liquid or aeriform bodies.
 A more profound examination,   and a  more connected
 analysis of the individuals, would soon convince him that
 the substances which certain general relations had induced
 him to unite in the same class, under a generic denomina-
 tion, differed very essentially among each other,  and that
 these differences necessarily required subdivision.   Hence
 he would divide his solid  bodies into stones, metals,  ve- 
14
PRELIMINARY DISCOURSE.
 getable substances, animal substances,  &c.;  his liquids
 would be divided into water,  vital  air, inflammable air,
 mephitic air, he.  When he  proceeded to carry his re-
 searches on the nature of these substances still farther, he
 would perceive that most of the individuals were formed
 by the union of simple principles;  and here it is that his
 applications of the system to be followed, in assigning a
 suitable denomination  to each substance,  would begin.
 To answer this purpose,  the authors of the New Nomen-
 clature have endeavoured to exhibit denominations which
 may point out the constituent principles.  This admira-
 ble plan has been carried into execution as far  as relates
 to substances which are  not  very complicated, such as
 the combinations of the  principles  with each other; the
 acids, earths, metals, alkalis, &c.  And this part of the
 Nomenclature appears to me to leave nothing more  to be
 desired.   The explanation may be seen in the work pub-
 lished on  this subject by the authors, and in the Elemen-
 tary Treatise of Chemistry  of Mr.  Lavoisier.  I shall
 therefore  do nothing more  in this place  than present a
 sketch of the method I have followed;  taking for exam-
 ple the combinations of acids, which form the most nume-
 rous class of compounds.
   The first  step consisted in comprehending under a ge-
 neral denomination the combination of an acid  with any
 given basis ^  and in order to observe a more exact arrange-
 ment, and at the  same time to  assist  the  memory, one
 common termination has  been given to all words which
denote the combination of an  acid.  Hence the words
 Sulphates, Nitrates, Muriates,  are used  to denote combi-
 nations of the sulphuric, nitric, and muriatic acids.   The
 kind of combination is denoted by adding to the generic
 word the name of the  body which  is combined with the
acid;  thus, the sulphate of pot-ash  expresses the combi-
nation of the sulphuric acid with pot-ash.
   The modifications  of  these same acids, dependant on
the proportions of their constituent principles, form salts
different from those we have just spoken of; and the au-
thors of the New Nomenclature have expressed the mo-
difications of the acids by the termination of the generic
 word.  The difference in the acids arises almost always
from the greater or less abundance  of oxigene.  In the 
             PRELIMINARY DISCOURSE.           1,5

first case, the acid assumes the epithet  of Oxigenated;
hence the oxigenated muriatic acid, the  oxigenated sul-
phuric acid, &c.  In the second case, the  termination of
the word which denotes the acid, ends in ous ;  hence the
sulphureous acid, the nitrous  acid, &c.   The combina-
tions of these last form sulphites, nitrites, &c; the com-
binations of the former compose oxigenated muriates, ox-
igenated sulphates, &c.
   The combinations of the various bodies which compose
this globe are not all as simple as those  here mentioned;
and it may be immediately perceived how long and trou-
blesome the denominations would  be,  if attempts were
made to bestow a single  denomination which should de-
note the constituent principles of a  body  formed by  the
union of five  or six  principles.  In this case, the prefe-
rence  has been given to the received appellation,  and no
other changes have been admitted but such as were neces-
sary in order to substitute proper appellations instead of
those  which afforded notions contrary to the nature of the
objects they were applied to.
   I have adopted this Nomenclature in my lectures, and in
my writings; I have not failed to perceive how very advan-
tageous it is to the teacher, how much it relieves  the me-
mory, how greatly it tends to produce a taste for  chemis-
try, and with  what facility and precision  the  ideas and
principles concerning the nature of bodies fix themselves
in the minds of the auditors.  But I have been careful to
insert the technical terms used in the arts,  or received in
society, together with these new denominations.  I am of
opinion that, as it is impossible to change the language of
the people, it is necessary to descend to them, and by that
means render them partakers of our discoveries.   We see,
for example, that the artist is acquainted with the sulphu-
ric acid by no other  name than that  of Oil of Vitriol,
though the name of the  Vitriolic Acid has been the lan-
 guage of chemists for a century past.  We cannot hope
 to be  more happy in  this respect than our predecessors;
 and, so far from separating ourselves from the artist by  a
 peculiar language, it is proper that we should multiply the
 occasions of bringing us together;  so far from attempting
 to enslave him by our language, we  ought rather to in-
 spire his confidence by learning his terms.  Let us prove 
16
PRELIMINARY DISCOURSE.
to the artist that our relations with him are more extended
than he imagines;  and let  us by  this intimacy establish
mutual correspondence, and a concurrence of information,
which cannot but redound to the advantage of the arts and
of chemistry.
   After having explained the principal  objections which
have retarded the improvement  of chemistry,  and the
causes which in our time have accelerated its progress, we
shall endeavour to point out the principal applications  of
this science;  in which attempt, we think, we shall succeed
best by casting a general retrospect over those arts and
sciences which receive certain principles from it.
   Most of the arts are indebted to accident for their dis-
covery.  They are in general neither the fruit of research,
nor the result of combination, but all of them have a more
or less evident relation to chemistry.  This science there-
fore  is capable of clearing up their first principles, reform-
ing their abuses, simplifying their operations, and accele-
rating their progress.
   Chemistry bears the same relation to most of the arts,
as the mathematics have to the  several  parts  of science
which depend on their principles. It is possible, no doubt,
that works of mechanism may be executed by one who
is no mathematician;  and so likewise it is possible to dye
a beautiful scarlet without being a chemist: but the ope-
rations of the mechanic, and of  the dyer, are not the less
founded upon invariable principles, the knowledge of which
would be of infinite utility to the artist.
   We continually hear in manufactories of the caprices and
uncertainty of operations;  but it appears to me that this
vague expression owes its birth  to the ignorance of the
workmen with regard to the true principles of their art.
For nature itself does not act with determination and dis-
cernment,  but obeys invariable laws; and the  inanimate
substance which we make use of in our manufactures, ex-
hibits necessary effects, in which the will has no part, and
consequently in which caprices cannot take place.   Ren-
der yourselves better  acquainted  with the materials you
work upon, we might say to the  artists;  study more  in-
timately the principles of your art;  and you will be able
to foresee, to predict, and to calculate every effect.   It is
your ignorance alone which renders your operations a con- 
PRELIMINARY DISCOURSE.           17
tinual series of trials,  and a  discouraging  alternative of
success and disappointment.
  The public, which continually exclaims that experi-
ence is better than science, encourages and supports this
ignorance on the part  of the artist;  and it will not be re-
mote from our object to attempt to ascertain the true va-
lue of these terms.   It is very true, for example, that a
man who has had a very long  experience  may perform
operations with exactness; but he  will always be  con-
fined to the mere manipulation.  I would  compare  such
a man to a blind person who is acquainted with the road,
and  can  pass  along it with ease, and perhaps even with
the confidence and assurance of a man who sees perfectly
well; but is at the same time incapable of avoiding ac-
cidental  obstacles, incapable of shortening  his way or
taking the most direct course, and incapable  of laying
down any rules which he can communicate to  others.
This is  the state of the artist of mere experience;  how-
ever long the duration of his practice may have been, as
the simple performer of operations.
   It may perhaps be  replied, that artists have made very
important discoveries in consequence of assiduous labour.
This is indeed true, but the examples are very scarce; and
we have no right to conclude, because we have seen men
of genius without any mathematical theory execute  won-
derful works of mechanism, that the mathematics are not
the basis, or that any one has a right to expect to become
a great mechanic without a profound study of mathema-
tical principles.
   It appears to be generally admitted at present, that
chemistry is the basis of the arts :  but the artist will not
derive from chemistry all the  advantages he has a right
to expect, until he has broken  through that powerful
barrier  which  suspicion, self-love, and  prejudice  have
raised between the chemist and himself.  Such philoso-
phers as have attempted to pass this line, have frequendy
been repelled as dangerous  innovators;  and prejudice,
which reigns despotically in manufactories,  has not even
permitted  it  to be thought that the processes were capa-
ble of improvement.
C 
18           PRELIMINARY  DISCOURSE.

  It is easy to shew the advantages which the arts might
obtain from chemistry, by casting a  retrospect over  its
applications to each of them in particular.
  1.  It  appears, from the writings  of Columella, that
the ancients possesseel a considerable extent of knowledge
respecting agriculture, which was at that time considered
as the first and noblest occupation of man.  But when
once the objects of luxury prevailed over those of neces-
sity, the cultivation of the ground  was left to the mere
succession of practice, and this first of the arts became
degraded by prejudices.
  Agriculture is more intimately connected with chemis-
try than is usually supposed.   It must be admitted that
every man is capable of causing ground to bear com;
but what a  considerable  extent  of knowledge  is neces-.
sary to cause it to produce the greatest possible quantity I
It is not enough,  for this purpose, to divide, to cultivate
and to manure any piece of ground : a  mixture is like-
wise inquired of earthy principles so well assorted, that
it may  afford a proper nourishment; permit the roots to
extend themselves to a distance, in order to draw up the
nutritive juices;  give the  stem a fixed base; receive,
retain, and afford upon  occasion the aqueous  principle,
without which  no vegetation can be performed.   It is
therefore essential to ascertain the nature of the earth, the
avidity with which it seizes water, its force of  retaining
it,  &c.; and these  requisites point to studies which will
afford principles not to be obtained by mere practice but
slowly and imperfectly.
  Every grain requires a peculiar earth.   Barley vege-
tates  freely among  the  dry remains  of granite ;  wheat
grows in calcareous earth,  &c.   And how can it be pos-
sible  to naturalize foreign products, without a sufficient
stock of knowledge to supply them with an earth similar
to that which is natural to them ?
   The disorders of  grain and forage, and the destruction
of the insects which devour them, are objects of  natural
history and chemistry: and we have seen  in  our own
times the essential  art of drying and  preserving grain,
and all  those details which are interesting in the prepara-
tion of bread,  carried by the labours of a few chemists 
PRELIMINARY DISCOURSE.
19
to a degree of perfection which seemed difficult  to have
been attained.
   The art of disposing stables in a  proper  manner, that
of chusing wrater adapted for the drink of domestic ani-
mals, the economical processes for preparing and mixing
their food, the uncommon talent  of supplying a proper
manure  suited to the nature of soils,  the knowledge ne-
cessary  to prevent or to repair the effects of blights—-all
come within  the province of chemistry; and without the
assistance  of this science our proceeding would  be pain-
ful, slow, and uncertain.
   We may at present insist upon the  necessity  of che-
mistry in  the various branches of agriculture  with  so
much the more reason, as government does not  cease to
encourage this first of arts by recompenses, distinctions,
and establishments; and the views of the state are for-
warded by the proposal of means to render this art flou-
rishing.   We see, with the greatest satisfaction,  that, by
a happy return of reflection, we  begin to consider agri-
culture  as the purest, the most fruitful, and the most na-
tural source of our riches.   Prejudices no longer tend to
oppress the husbandman.  ' Contempt  and servitude are
no longer  the inheritance received for his  incessant la-
bours.   The most  useful and the most virtuous class of
men is  likewise that whose state is most minutely  consi-
dered ;  and the  cultivator of the ground in France is at
last  permitted to raise his hands in a state of freedom to
heaven,  in gratitude for this happy revolution.
   2.  The working of  mines is likewise founded upoa
the  principles of chemistry.  This  science alone  points
out and directs the series of operations to be made upon
a metal, from the moment of its extraction  from  the
earth until it  comes to be used  in the arts.
   Before the chemical analysis  was  applied to the exa-
mination of stones,  these substances were all denoted by
superficial characters, such as colour, harclness,  volume,
weight,  form, and  the property  of  giving fire with the
steel.  All these circumstances  had given rise  to me-
thods of division in which every other property  was con-
founded ;  but the successive labours of Pott,  Margraaff,
Bergmann, Scheele, Bayen, Dietrich, Kirwan, Lavoisier,
De Morveau, Achard, Sage, Beri^iollet, Jerhard, Erhmann, 
20           PRELIMINARY DISCOURSE.

Fourcroy, Mongez, Klaproth, Crell, Pelletier, De la Me-
therie, &c by instructing us concerning the constituent
principles of every known stone, have placed these sub-
stances in their proper situations, and  have carried  this
part of chemistry to the same degree of precision as that
which we before possessed respecting the neutral salts.
  The natural history of the mineral kingdom, unassisted
by  chemistry, is a language composed of a few words,
the knowledge of which has acquired the name of Mine-
ralogist to many persons.   The words Calcareous Stone,
Granite, Spar, Schorle,  Feld  Spar,  Schistus, Mica, &c.
alone  compose the dictionary of several amateurs of na^
rural history ; but the disposition of these substances  in
the bowels of the earth,  their respective position  in  the
composition  of the globe, their formation and successive
decompositions, their uses in die arts, and the knowledge
of  their constituent principles, form a science which can
be  well known and investigated by the chemist only.
  It is necessary therefore that mineralogy should be en-
lightened by  the  study of chemistry ; and we may  ob-
serve that, since these two sciences have been united, the
labour of working mines has been  simplified, metallic
ores have been wrought with more intelligence, several
new metallic substances have been  discovered, individu-
als  have opened mines in the  provinces; and we have
become familiar with a species of industry which seemed
foreign,  and almost  incompatible with our soil and  our
habits.  S<eel and the  other metals have received in our
manufactories that degree of  perfection  which had till
lately excited our admiration,  and humiliated  our  self-
love.  The superb manufacture of Creusot has no equal
in Europe.   Most of our works are supported by  pit-
coal ; and this new combustible substance is so much the
more valuable, as it  affords  us time to repair our  ex-
hausted woods, and  as it is found almost every where in.
those barren soils which repel the ploughshare, and  pro-
hibit every other  kind  of industry.  The eternal grati-
tude of this  country is therefore  due to  Messrs. Jars,
Dietrich, Duhamel,  Monet,  Gensanne,  &c.  who  first
brought us acquainted with these true riches.   The taste
for mineralogy, which has diffused itself within our re-
membrance, has not a little contributed to produce  this 
PRELIMINARY DISCOURSE.
21
revolution ;  and it  is  in a great measure owing to those
collections of natural history, against  which  some  per-
sons have so much  exclaimed, that we  are  indebted for
this general, taste.   Our collections have  the  same  rela-
tion to natural history, as books bear  to literature and
the sciences.  The collection frequently is nothing more
than an object of luxury to the proprietor; but  in this
very case it is a resource always open to the man who is
desirous of beholding, and instructing himself.   It is an
exemplar of the works  of nature,  which may be  con-
sulted ever}' moment; and  the  chemist who runs  over
aU these productions,  and  subjects  them to analyses  to
ascertain their constituent principles, forms the precious
chain which unites  nature and art.
   3.  While the chemist attends to the nature of  bodies,
and endeavours to  ascertain their constituent principles,
the natural philosopher studies their external characters,
and as it were their physiognomy.   The object of the
chemist ought therefore to be  united to that of  the phi-
losopher, in order  to  acquire a complete idea of a bod}'.
What in fact shall we  call air or fire, without the instruc-
tion  of the chemist ? Fluids more or  less compressible,
ponderous, and elastic.  What are the  particulars of in-
formation which natural  philosophy affords us concerning
the nature of solids ? It  teaches us to distinguish them
from each  other,  to calculate their weight, to determine
their figure, to ascertain their uses,  &e.
   If  we cast our attention upon the numerous  particu-
lars which chemistry has lately taught  us respecting air,
water, and fire, we shall perceive how much the connex-
ion of these two sciences  has been strengdiened.  Be-
fore  this revolution, natural philosophy was  reduced to
the simple  display  of machines;  and this  coquetry, by-
giving it a transient glare,  would have  impeded its  pro-
gress, if chemistry had not restored it to its  true desti-
nation.   The celebrated  chancellor Bacon compared the
natural  magic,  or  experimental philosophy, of his time,
to a  magazine in which a few  rich  and valuable move-
ables were found among a  heap of toys.   The curious,
says  he, is  exhibited instead of the  useful.   What more
is required to draw the attention  of great men,  and  to 
22
PRELIMINARY DISCOURSE.
 form that transient fashion of the day which ends in con«
 tempt ?
   The natural philosophy of our days no longer deserves
 the reproaches of this celebrated philosopher.   It is a
 science founded on two bases equally solid.   On the one
 part, it depends  on mathematical science for  its princi-
 ples ; and on the other, it rests upon chemistry.   The na-
 tural philosopher will attend equally to both sciences.
   The study of chemistry, in certain departments, is so
 intimately connected with that of natural philosophy, that
 they are  inseparable;  as, for example, in researches con-
 cerning air, water, fire, &c.  These  sciences very advan-
 tageously assist each other  in  other  respects;  and while
 the chemist clears minerals from the  foreign bodies which
 are combined with them, the  philosopher supplies the me-
 chanical  apparatus necessary  for  exploring  them.  Che-
 mistry is inseparable from natural philosophy even in such
 parts as appear the most independent of it;  such, for ex-
 ample, as optics,  where the natural philosopher can make
 no progress but  in proportion as the chemist shall bring
 his glass to perfection.
   The connexion between  these two sciences is  so inti-
 mate, that it is difficult to draw a line of distinction be-
 tween them.   If  we  confine natural philosophy to inqui-
 ries relative to the external properties of bodies, we shall
 afford no other object but the mere outside of things.  If
 we restrain the chemist to  the mere analysis, he  will at
 most arrive at the knowledge of the constituent principles
 of bodies, and will be ignorant of their functions.   These
 distinctions in a science which has but one common pur-
 pose, namely, the complete knowledge of bodies,  cannot
 longer exist; and it appears to me  that we ought abso-
 lutely to  reject them in all objects which can only be well
 examined by  the union of natural  philosophy "and che-
mistry.
   At the period of the revival of  letters, it was of advan-
 tage ,to separate the learned, as it were, upon the road to
 truth ;  and to multiply the  workshops, if I may use the.
 expression to hasten the clearing  away.   But at  present,
 when the various points are re-united, and the connexion
 between  the whole is seen,  these  separations,  these divi- 
PRELIMINARY DISCOURSE.
23
sions, ought to be effaced; and we  may flatter ourselves
that, by uniting our efforts, we may make a rapid progress
in the study of nature.  The meteors,  and all the pheno-
mena of which the atmosphere is the grand theatre, can
be known only by this re-union.  The decomposition  of
water in the bowels of the earth, and its formation in the
fluid which surrounds us,  cannot but give rise to the most
happy and the most sublime  applications..
   4.  The  connexion between chemistry and pharmacy is
so intimate, that these two sciences have long been consi-
dered as one and the  same;  and  chemistry, for a long
time, was cultivated only by physicians and apothecaries.
It must be allowed that, though the chemistry of the pre-
sent day, is very different  from pharmacy, which is only
an  application of the general principles of this science,
these applications are  so numerous, the class  of persons
who cultivate pharmacy is in general so well informed,
that it is not at all to be wondered at, that most apotheca-
ries should endeavour to  enlighten their profession by a
serious  study of chemistry, and by the happiest agreement
unite the knowledge of both parts of science.
   The  abuses which, at the beginning of the present cen-
tury, were  made of the applications of chemistry to medi-
cine, have caused the natural  and intimate relations of this
science  with the  art of healing to be mistaken.   It would
have been  more  prudent, no doubt,  to have rectified its
applications; but unfortunately we have too much ground
to reproach physicians for  going to extremes.  They have,
without restriction, banished  that which they before re-
ceived without examination;  and we have seen them suc-
cessively deprive their art  of all the assistance it might ob-
tain from the auxiliary sciences.
   In order to direct with propriety the applications of che-
mistry to the human body, proper views must be adopted
relating  to  the animal economy, together  with  accurate
notions of chemistry itself.  The results of the laboratory
must be considered as subordinate to physiological obser-
vations.   We should endeavour to enlighten  the one by
the other,  and to admit no truth as established which is
contradicted by any of these means of conviction.   It is in
consequence of a departure from these principles that the
human body  has been considered as  a lifeless and passive 
24
PRELIMINARY DISCOURSE.
substance ; and  that the strict principles observed in the
operations of the laboratory have been applied to this liv-
ing system.
  In the mineral kingdom, every thing is  subjected to
the invariable laws of the  affinities.  No internal princi-
ple modifies the  action of  natural agents; and  hence it
arises that we  are capable of foretelling, producing or
modifying the effects.
  In the vegetable  kingdom, the action of external agents
is equally evident; but the internal organization modifies
their effects, and  the  principal  functions of vegetables
arise from the combined  action  of external and internal
causes.   It was  no doubt for this reason that the Creator
disposed the principal organs of vegetation upon the sur-
face of the plant, in order that the various functions might
at the  same time  receive the  impressions of external
agents, and that of the internal principle of the organiza-
tion.
  In animals the functions are much  less dependant on
external causes; and nature  has concealed the principal
organs in the internal parts of their bodies, as if to with-
draw them from the influence of foreign  powers.   But
the more the functions  of an individual are connected
with its organization, the less is the empire of chemistry
over them;  and it becomes us to be cautious  in the ap-
plication of this science to all the phenomena which de-
pend essentially upon the principles of life.
   We must not, however, consider chemistry as foreign
to the  study and practice of medicine.   This science
alone can teach us the difficulty and  art of combining
remedies.   This alone can teach us to apply  them with
prudence and firmness.  Without  the assistance  of this
science, the practitioner would scarcely venture to apply
those powerful remecjies from which the chemical physi-
cian knows the means of deriving such great advantage.
Chemistry alone in all probability, is capable of affording
means of combating epidemic disorders,  which in  most
cases are caused by an alteration in the air, the water, or
our food.  It will  be only in consequence of analysis that
the true remedy can be found against those stony concre-
tions which form  the matter of the gout,  the stone,  the
rheumatism, &c.; and the valuable particulars of infor- 
PRELIMINARY DISCOURSE,           25
 mation which we now possess respecting respiration,  and
 the nature of the principal humours of the human  body,
 are likewise among the benefits arising from this  science.
   5.  Chemistry is not only of advantage to agriculture,
 physic, mineralogy, and medicine, but its phenomena are
 interesting to all the orders of men :  the  applications of
 this  science  are so numerous,  that there are few circum-
 stances of life in which the  chemist does not enjoy  the
 pleasure of seeing its principles  exemplified.  Most  of
 those facts which habit has led us to view with indifference
 are interesting phenomena  in  the  eyes  of the chemist.
 Every thing instructs and amuses him; nothing is  indif-
 ferent to him, because nothing is foreign to his pursuits ;
 and  nature, no less beautiful in her most minute details
 than sublime in the disposition of her general laws, ap-
 pears to display the whole of her magnificence only to the
 eyes of the chemical philosopher.
   We might easily form an idea of this science, if it were
 possible to exhibit in this place even a sketch of its prin-
 cipal applications.  We should see,  for  example, that
 chemistry afforeis  us all the metals of  which the uses are
 so extensive ;  that chemistry affords us the means of em-
 ploying the parts of animals and of plants for our  orna-
 ment ; that our luxuries, and our subsistence, are by this
 science established as a tax upon all created beings ; and
 that by this power we are taught to subject nature to our
 wants, our taste,  and even  to  our caprices.   Fire, that
 free independent element, has been collected and govern-
 ed by the industry  of the chemist; and this agent, de-
 stined to  penetrate, to enliven, and to animate the whole
 of nature, has in his hands  become the agent of death,
 and  the  prime minister of destruction.   The chemists
 who in our time have taught us to insulate  that pure  air
 which alone is proper for combustion,  have placed in our
 hands, as it were,  the very essence of  fire; and this ele*
ment,  whose effects were so terrible, becomes the agent
 of still more terrible consequences.   The atmosphere,
 which was formerly considered as a mass of homogeneous
fluid,  is now found to be a Drue chaos, from which ana-
 lysis has obtained principles  so much the more interesting
to be known, as nature has made them the principal agents
 of her operations.   We may consider this mass of fluid in
                         D 
26
PRELIMINARY DISCOURSE.
 which we live as a vast laboratory, in which the meteors
 are prepared, in which all the seeds of fife and of death arc
•developed,-from which nature takes  the  elements of the
 composition of bodies, and to which their subsecjuent de-
 composition returns the same principles which were be-
 fore extracted.
   Chemistry, by informing us of  the nature and princi-
 ples of bodies, instructs us perfectly concerning  our rela-
tion to the objects around us.   This  science teaches us,
 as it were, to live with them;  and  impresses a true life
upon them, since by this means each body has its name,
 its character, its  uses, and  its  influence, in the harmony
 and arrangement of this universe.
   The chemist,  in the midst of those numerous beings
 which the common race of men accuse  nature of having
'vainly placed upon our  globe, enjoys the prospect as it
 Were in the centre of a society, all  whose  members are
 connecteel together by intimate relations, and concur to
 promote the general  good.   In his  sight  every thing is
 animated, every being performs a part on this vast theatre;
 and the chemist who participates in diese interesting scenes,.
 is repaid with usury for  his first exertions to discover the
 relations existing between them.
   We may even consider this commerce, or mutual rela-
 tion between the chemist and nature, as very proper to
 soften the manners, and to impress on the character that
 freedom and firmness of principle so valuable in society.
 In the study  of natural history,  no cause ever presents it-
 self to complain of inconstancy or treachery.  An attach-
 ment  is easily  contracted for objects which afford enjoy-
 ment only;  and these connexions are as pure as their ob-
ject, as durable as nature, and stronger in proportion to the
 exertions which have been required to establish them.
   From all these  considerations, there is no science which
 mere eminently deserves to enter into the plan of a good
 education than chemistry.  We may even affirm that the
 study of this science is almost indispensably necessary to
■prevent us from being strangers in the midst of the beings
 and phenomena which surround us.   It is true indeed that
 the habit of beholding the objects of  nature may produce
 a knowledge of some of their principal properties.  We
 may even in  this way arrive at the theory of some  of the 
PRELIMINARY DISCOURSE.
27
phenomena.   But nothing  is more proper to check tlie
pretentions of young persons who are elevated by such im-
perfect acquisitions,  than to shew them the vast field of
whic'. they are ignorant.  The  profoundest sentiment of
their  ignorance will be  seconded by the natural desire of
acquiring new knowledge.  The wonderful properties of
the objects presented to them will engage their attention.
The  interesting nature of the phenomena will tend to ex-
cite their curiosity.  Accuracy of experiment, and strict-
ness of result, will form their reasoning powers, and render
them severe in their judgment.   By studying the proper-
ties of all the bodies which surround him, the young scho-
lar learns to know their relation  with himself; and by suc-
cessively attending  to all  objects,  he  extends  the  cir-
cle of his enjoyment by new conquests.   He  becomes  a
partaker  in the privileges of the Creator, by uniting and
disuniting, by compounding and destroying.  We might
even affirm that the  Author of nature, reserving to himself
 alone the knowledge of his general laws, has placed man
. between  himself and matter, that it may receive these laws
 from his hands,  and that he may apply them with proper
 modifications and restrictions.   In this view, therefore, we
 may consider man as greatly superior to the other beings
 which compose this living system.   They all follow a mo-
 notonous and invariable process; receive the laws, and sub-
 mit to effects without  modification-  Man alone possesses
 the rare advantage of knowing a part of these laws, ofpre-
 paring events, of predicting results, of  producing effects
 at pleasure, of removing whatever is noxious, of approf
 priating whatever is beneficial,  of  composing substances
 which nature herself never forms;  and, in this last point
 of view,  himself a Creator,  he appears to partake with the
 Supreme Being in the most eminent of his prerogatives- 
 
ELEMENTS OF  CHEMISTRY.
        PART THE FIRST.

Concerning the Chemical Principle^.
                  INTRODUCTION..

Definition of Chemistry; its Object and Means—Description of -#
  Laboratory, and the principal Instruments employed in chemical
  Operations, with a Definition of those Operations.

     CHEMISTRY is a science, the object of which is to
      ascertain the nature and properties of bodies.
   The  methods  used to  obtain this knowledge are re-
ducible to two; analysis and synthesis.
   The principal operations of chemistry are performed in
a place called a Laboratory.
   A laboratory ought to be extensive and well  aired,  in
order to prevent dangerous vapours from remaining, which
are produced in some operations, or which may escape by
any unforeseen  accident.  It ought  to be  dry, because
otherwise iron vessels would rust, and most  of the  chemi-
cal products would be liable to change.  But the  princi*
pal excellence of a laboratory consists in its being furnish-
ed with all those instruments which may be employed in
the study of the  nature of bodies, and in  inquiries res-
pecting their properties.
   Among these instruments  there are some which are of
general use, and applicable to most operations;  and  there
are others which serve only for peculiar uses.   This divi-
sion immediately points out that, at the present instant, we
can only treat of the former,  and that we must describe
the others on such occasions as will render it necessary to
treat of their uses* 
30
THE EVAPORATORY FURNACE.
  The  chemical instruments most frequently employed
are  those which present themselves first to view upon en-
tering a laboratory; namely, the furnaces.*
  These furnaces consist of earthen vessels appropriated
to the various operations performed upon bodies by means
of fire.
  A proper  mixture of  sand and  clay is  commonly the
material of which these vessels are formed.   It is difficult,
and even impossible, to prescribe and determine,  accord-
ing to any invariable method, the proportions of these con-
stituent parts;  because they must be varied according to
tta  nature of the  earth made use of.   Habit  and  experi-
ence alone can furnish us with principles on this subject.
  The  several methods of applying fire to  substances un-
der examination, has occasioned the construction  of fur*
•naces in different forms, which we shall at  present reduce
to the three following.
  I. The evaporatory furnace.—This furnace has received
its name from its use.  It  is used to reduce liquid sub-
stances into vapour  by means of heat, in order to separate
the more fixed principles from those which are more pon-
derous; and were  mixed,  suspended,  compounded,  or
dissolved in  the fluid.
  The fire-place is covered by the evaporatory vessel.
Two or three grooves,  channels,  or depressions are  made
in the sides of the furnace near its upper edge, to facilitate
the drawing of the fire.
   The vessel which contains  the substance to be evapo-
rated, is called the evaporatory vessel.
   These vessels are formeel of earth,  glass or metal.   Ves-
sels of unglazed earth are too porous, insomuch that liquids
filtrate  through  their texture.  Those  of porcelain bis-
cuit are likewise penetrable by  liquids strongly  heated,
and suffer gaseous or aeriform substances to escape. The

   * The only  furnaces to be procured in the United States, are made
of thick sheet  iron, and they  are very durable and cheap.   The one,
 plate 2, fig. 1.  is ten inches high from the grate, and ten inches in di-
 ameter.  Two round holes, two and a half inches wide, are made in
the middle of the sides, in order to submit many substances to a high
 degree of heat, in order to transmit liquids  or gases over th'.m, in
 an  earthen, copper or iron tube.  A common chafing-dish, is a rery
"useful furnace, in a great many chemical operations.      Am. Ed. 
          CHEMICAL VESSELS  OP EARTH, &X.       31

.Beautiful experiments of Mr. D'Arcet upon the combus-
tion and destruction of the diamond, in balls of porcelain,
are well  known, and tend to illustrate this subject.  I have
confirmed these results by experiments in the large way,
upon die distillation of acjua-fortis, which loses as well in
quality as quantity when the process is carried on in vessels
of porce iidii clay.
   Glazed earthen vessels cannot be used when the  glass
consists  of the calces of lead or copper;  because those me-
tallic matters are attacked by acids, fats, oils, <kc. . Neither
can earthen vessels be used which  are covered with ena-
mel, because this kind of opake glass is almost always fall
of small cracks, through which the liquid would introduce
itself into die body of the vessel.
   Earthen vessels cannot therefore be used, excepting in
operations of little delicacy, in which precision and accu-
racy are not indispensably required.
   Evaporatory vessels of glass are in general to be prefer-
red.   Those which resist the fire  better than any others,
are prepared in the laboratory, by cutting a sphere of glass
or a receiver into two equal parts with a red-hot iron.  The
capsules which are made in the glass-house are thickest at
the bottom, and consequently are more 'liable to break at
that part when exposed to the fire.
   Evaporatory vessels of metal are used in manufactories.
Copper  is most commonly employed,  because  it not only
possesses the  property of resisting fire,  but has a conside-
rable degree of solidity, together with the facility of being
wrought.  Alembics are made of this metal, for the distil-
lation  of vinous spirits, and aromatic  substances;  as are
also caldrons or pots for the crystallization of certain salts,
and for several dying processes,  &c.  Lead is likewise of
considerable use, and is made choice of whenever opera-
tions are to be performed upon  substances which contain
the sulphuric acid, such as the sulphates of alumine and of
iron;  and for the concentration  and rectification of the oil
of vitriol.  Tin vessels are also employed in some  opera-
tions:  the scarlet bath affords a more beautiful colour in
boilers of this metal than in those of any other.. Capitals
of tin  have already begun to be substituted in the room of
those  of copper, in the construction of  alembics;  and by
this means thq several products  of  distillation are ex- 
i'2        APPLICATION OF HEAT.  BATHS,
empted from every suspicion of that dangerous  metal,
Boilers of iron are likewise used for  certain coarse  opera-
tions;  as, for example, in the concentration of the.  lixivi-
urns of common salt, of nitre, &c.
   Evaporatory vessels of gold,  of silver, or of platina, are
to be preferred in some delicate operations; but the price
and scarcity of these vessels do not permit them to be used,
especially in the large way.
   Moreover it is from the nature of the substance  to  be
evaporated, that we must determine the choice of the ves-
sel most suitable to any operation.  There is no particular
kind of vessel which can be adapted exclusively on all oc-
casions.   It may only be observed, that glass presents the
greatest number of advantages,  because it is composed of
a substance the least attacked,  the least soluble, and the
least destructible by chemical agents.
   Evaporator}- vessels are known by the name  of capsules,
cucurbits, &c. according to their several forms.
   These vessels ought in general to be very wide and shal-
low, in order that the distillation and  evaporation may be
speedy and economical.  It is necessary, 1. That the eva-
poratory vessel be not narrow at its upper  part.  2.  That
the heat be applied to the liquid in all parts, and equally.
3. That the column or mass of the liquid should have lit-
tle depth, and a large surface of evaporation.  It  is upon
these principles that  I  have  constructed,  in Languedoc,
boilers  proper for distilling brandy,  which save eleven-
twelfths of the time, and four-fifths of the combustibles.
   Evaporation may be performed in  three manners.   I.
By a naked fire.  2. By the sand bath.  3. By the  water
bath*
   Evaporation is made by a naked fire, when  there is  no
substance interposed between the fire and the vessel which
contains the liquid intended to be evaporated; as, for ex*
ample, when water is boiled in a pot.
   Evaporation is performed by the sand bath, when a ves-
sel" filled  with sand is interposed between the  fire and die
evaporatory  vessel.   The heat is in this case communi-
cated more slowly and  gradually; and the  vessels, which
would otherwise have been broken by the  immediate ap-
plication of the heat, are enabled to resist its force.  The
heat is at  the same time more equally kept up; the refri- 
THE WATER BATH.  SUBLIMATION.
33
geration is  more  gradual;   and the operations are per-
formed with a greater degree of order, precision, and fa-
cility.
  If,  instead of employing a vessel filled with sand,  we
use a  vessel of  water,  and  the  evaporatory vessel  be
plunged in  the liquid, the evaporation is said to be m:ch
on the water bath:  in this case the substance to be eva-
porated is only heated by communication from the  water.
This  form or method of evaporating is  employed wh.n
certain principles of great volatility, such  as alcohol, or
the aiomatic principles of plants, are to  be extracted or
distilled.  It  possesses  the advantage of affording pro-
ducts which are not changed by the fire, because the lieat
is transmitted to  them by the intervention of a liquid  : it
is this circumstance which renders the  process va; liable
for the extraction of volatile oils, perfumes, ethcieal li-
quids,  &x.  It possesses  the advantage  of affording a
heat  nearly equal, because the degree of ebullition  is a
term nearly constant; and this standard  heat may be gra-
duated or varied at pleasure, by adding  s, ks to the liquid
of  the water bath, because this single circumstance ren-
ders  'the ebullition  more or  less quick and easy.  The
same effect may likewise be produced by  restraining  the
evaporation ;  for in this case the liquid may assume a de-
gree  of heat much more  considerable, as is seen in the
digester of Papin, steam engines, eolipiles,  and the boil-
ers for striking the red tinge in cotton.
   Sublimation  differs from evaporation,  because the sub-
stance to be  raised  is solid.   The vessels used in  this
operation are known by the name of sublimatory vessels.
These are commonly globes terminating in a long neck :
they  are  then called matrasses.*
   In order to sublime any substance,  a part of the  ball
of  the matrass is  surrounded  with sand.   The  matter"
which is volatilized by the -heat, rises, and is condensed
against the coldest part of the  vessel; where  it forms a
stratum or  cake,  that may  be taken out  by  breaking the  "
 vessel itself.  In this manner it is  that sal ammoniac, cor.-

   * Vessels for subliming should be of a circular form, shaped
 fiat like a turnip, and have a projectingneck, two or three inches
 in length, with an aperture in it, about an .inch in diameter.  Vide
 plate  ii. figure 3.  Am. Ed-
                           E 
34     REVERBERATORY  FURNACE.   RETORTS.

rosive sublimate, and other  similar products, are formed
for the purposes of commerce.
  Sublimation is usually performed either for the purpose
of purifying  certain  substances, and  disengaging  them
from  extraneous matters; or else  to reduce into vapour,
and combine  under  that form,  principles  which  would
have united with  great  difficulty  if they had not been
brought to that state of extreme division.
  II.  The reverberatory furnace.—The name of the re-
verberatory furnace has been given to that construction
which is appropriated to distillation.
  This furnace is composed of four parts.   1. The ash-
hole intended for  the free passage of the air, and to re-
ceive  the ashes  or  residue  of the  combustion.  2.  The
fire-place,  separated from the ash-hole by the  grate, and
in which the combustible matter is contained.   3. A por-
tion of a cylinder, which is called the laboratory, because
it is this part which receives the retorts employed  in  the
operations  or distillations.   4.  These three pieces are co-
vered with a dome,  or portion of a sphere, pierced  near
its upper part  by an aperture, which affords  a free  pas-
sage to the current  of air,  and  forms  a  chimney.  The
most usual form of the reverberatory furnace is  that of a
cylinder terminated by a hemisphere, out of which arises
a chimney  of  a  greater or less length,  to  produce a suit-
able degree of aspiration.
  In  order that a reverberatory furnace may be well pro-
portioned,  it is necessary, 1. That  the ash-hole should be
large, to admit  the air fresh and unaltered.   2.  That the
fire-place and  laboratory together  should have the form
of a true ellipsis, whose two foci should be  occupied  by
the fire and the  retort.  In this case all the heat, whether
direct or reflected,  will strike the retort.
  The reverberatory furnace is used for distillation.  Dis-
tillation is  that process by  which the force  of fire  is  ap-
plied to disunite and separate the several principles of bo-
dies, according to the laws of their volatility,  and their
several affinities.
  Distilling vessels are known by  the name of retorts.
  Retorts are  formed of glass,  of  stone-ware,  of porce-
lain,  or  of metal;  these  substances  being  respectively 
RECEIVERS.   FURNACES.             35
used, according to the nature of the bodies intended to
be exposed to tiistillation.
  Whatever be the nature of the material,  the  forms of
retorts are the same.   This figure resembles an egg, ter-
minating in a  beak or tube, which diminishes  insensibly
in diameter,  and is slightly inclined or bended.
  The oval portion of the retort, which is called its belly,
is placed in  the laboratory of the furnace, and is sup-
ported upon two bars of iron, which separate the labora-
tory from the fire-place; while the beak  or neck  of the
retort issues out of the furnace through  a  circular aper-
ture formed in the edges of the dome and of the labora-
tory.*                                             .  .
   A vessel intended to receive the product  of  the distil-
lation is fitted to the neck of the  retort.   This vessel is
called the recipient, or receiver.
   The receiver is commonly a sphere with two  apertures :
the one of considerable  magnitude, to receive  the  neck
of the retort;  the  other smaller,  to afford vent for the
 vapours.  This part  is called the  tubulure of the receiv-
er ; whence the terms tubulated receiver, or receiver not
 tubulated,  &c.
   Though  the reverberatory furnace  be particularly
adapted to  distillation,  this  operation  may be perform-
ed on the sand-bath;  and here,  as in other cases,  it de-
 pends singly on the intelligence of the artist to vary his
 apparatus according  to the necessity of  circumstances,
 and the nature of the substances upon which he ope«r
 rates.
    The construction of these furnaces may likewise be va-
 ried; and  the chemist will find it necessary to  learn
 the art of availing himself of every apparatus he pos-
 sesses, to carry his operations into execution: for  if he
 should persuade himself that it is impossible to proceed in
 chemical research, excepting in a laboratory provided with
 all suitable vessels; he may let the moment pass in which
 a discovery might  be made, but which may not again re-
 turn.  And it may truly be said,  that he who treads ser-
 vilely  in the  paths of  others who have gone before him,
 will never attain to the discovery  of new truths.

   * The neck of a glass retort,  should be two  feet  in length, in
 •rder to guard  the receiver, from the action  of heat.  Am. Eds 
36         FORCE  FURNACE.  CRUCIBLES.
  III.  The forge furnace.—The forge furnace is that io
which  the current of air is determineel by bellows.   The
ash-hole, the" fire-place, and  the laboratory are here  all
united  together, and this assemblage forms only a portion
of a cylinder, pierced near the lower angle by  a small
hole, into which the tube of the bellows enters.  This part
is sometimes covered with a hemisphere or dome, to con-
centrate the heat with  greater efficacy,  and to  reflect it
upon the bodies exposed to it.  The forge furnace is em-
ployed in the fusion and calcination of metals, and gene-
rally for all the operations which are performed in crucibles.
  By  crucibles we understand vessels of earth or metaly
which  are almost always of the form of an inverted cone.
A crucible ought to support the strongest heat  without
melting:  it ought to  resist the attacks of all such agents
as aie  exposed to  heat in vessels  of this kind.  Those
Crucibles which possess the greatest degree of perfection,
are made in Hesse or in Holland.  I have  made very
good ones by a mixture of raw  and  unbaked  clay  from
Sulavas in the Vivarais.
   Our laboratories have been provided with crucibles of
platina, which unite the most excellent properties.  They
are nearly infusible, and at the same time indestructible
by the fire.*
   The several earthen vessels concerning which we have
here treated, may be fabricated by  the hand, or wrought
in  the lathe.   The first  proceeding renders them more
•solid,  the  clay is better united, and it is the only method
used in glass manufactories; but the second method is
more expeditious.
   The agent of such decompositions as  are  effected by
means of furnaces, is fire.  It is afforded by the combus-
tion of wood, pit-coal, or  charcoal.
   Wood is only employed in certain large works; and
we prefer charcoal in our laboratories, because it does not
smoke, has no bad smell, and burns better in small mas-
ses than other combustibles.  We choose  that which is
the .most sonorous, the driest, and the  least porous.

   * Crucibles of cast iron, which are  extremely useful, and con-
venient, may be obtained at  any of the iron works in the United
States.  Am. Ed. 
        LUTES  AND COATINGS  FOR  RETORTS.      37

   But in the several operations we are about to describe,
it is necessary  to defend the  retorts from the immediate
action of the fire ;  and also to coerce and restrain the ex-
pansible vapours,  which are very elastic,  and frequently
corrosive.   It is to answer these purposes that various
lutes are employed.
   1. A glass retort exposed to the action of the fire would
infallibly break, if  the  operator were not to have recourse
to the prudent precaution of coating it with earth. *
   I have found it advantageous for the coating of retorts,
to use a mixture of fat earth  and fresh horse dung :  for
this purpose,  the  fat  earth is suffered to rot  for  some
hours in water; and when it is moistened, and properly
softened, it must be kneaded with  the horse dung, and
formed  into a soft  paste, which is to be  applied and
spread with  the hand  upon  every  part  of the  retort in-
tended  to be  exposed to  the action  of the fire.   The
horse dung  combines  several advantages.  1.  It contains
a serous  fluid,  which hardens by heat, and strongly con-
nects all the parts together: when this juice  has  been
altered by fermentation or age, the dung  does not pos-
sess the same virtue.   2. The filaments or stalks of hay,
which are so easily distinguished  in  horse  dung,  unite
all the parts  of the lute together.
   Retorts luted in this manner resist  the  impression of
the fire very well; and the adhesion  of the lute  to  the
retort is such,  that even should the  retort  fly during  the
operation, the distillation may be still carried on, as I have
daily experience in works in the large  way,
   2. When it is required to  coerce  or oppose the escape
of the vapours which  are  disengaged  during  an}- opera-
tion it is no doubt  sufficient if the joinings  of the  vessels
be covered with paper  glewed on, or with slips of  blad-
der moistened with the lute  of lime and  white of egg,
provided the vapours be neither dangerous  nor corrosive;
but, when the vapours are corrosive,  it is necessary to
use the fat lute to  retain them.

   * It is very rarely necessary to coat a glass jetort, in the man-
ner recommended by the author.  The flame of an Argand lamp,
may be  at any time  applied to its bottom,  without any danger of
its cracking.  Am. Ed. 
 38         lutes,   woulfe's  apparatus.

   Fat lute  is made  with boiled linseed  oil mixed and
 well  incorporated with sifted  clay.   Nut  oil, kneaded
 with the same clay, forms a lute possessing the same pro-
 perties.  It is easily extended in the hand, and is  used
 for defending the joinings of vessels,  upon which it is af-
 terwards secured by strips of linen, dipped in the lute of
 lime  and white of egg.   Before the application of heat
 in any distillation, it is necessary first to  suffer the  lutes
 to  dry.  Without  this precaution, the  vapours would
 rise and escape;  or otherwise they would combine  with
 the water which moistens the lutes, and  would corrode
 and destroy the bladder,  the skin, the paper, and  in  a
 word every substance used to secure them in their places*
 The lute of lime and white of egg dries very speedily,
 and must be used the moment it  is made.  This  lute,
 likewise, opposes the  greatest resistancev to the escape of
 the vapours, and adheres the most intimately to the glass.
 It is  made by mixing a small quantity of finely-pow-
 dered quick-lime with white of egg, and afterwards beat-
 ing up the mixture to facilitate the combination.   It
 must then be instantly applied on pieces  of old linen, to
 be  wrapped round the places of joining.*
  In  the large works, where it is not possible to attend to
 all these minute details, the joinings of the retort and re-
 ceiver are  luted  together with the same lute which is
 used  to coat the retorts.   A covering of the thickness of
 a few lines is sufficient to prevent the vapours  of the ma-
 rine or nitrous acid from escaping.
  As in certain operations a disengagement takes place
 of so prodigious  a quantity of vapours, that it  is danger-
 ous to confine them;  and as, on the other hand, the suf-
fering them to escape would occasion a considerable loss
in the product; an apparatus has been contrived of great
ingenuity and simplicity to moderate the issue, and to re-
tain without risk such vapours as  would otherwise es-
 cape.   This apparatus is known by the name  of its  au-
thor, Mr. Woulfe, a famous English chemist   His most  '
excellent process  consists  in adapting the  extremity  of  a
recurved tube to the tubulure of the receiver;  the other

  *  A lute made of flour and water, and spread upon paper, and
applied where the retort joins the receiver, is one of the  best,
that has ever been  used. Am. Ed. 
WOULFE's APPARATUS'.
3$
end of which is plunged into water, in a bottle half filled,
and properly placed for that purpose.   From the empty
part of this bottle issues a second tube, which is in  like
manner  plunged  in the  water of a  second bottle.  A
number of  othef  bottles  may be  added, observing the
same  precautions;  with the attention, nevertheless, to leave
the last open, to give a free escape to the vapours which are
not coercible: and, when the apparatus is thus disposed, all
the joinings are to be luted.   It will easily  be imagined
that the vapours which escape from the retort are obliged
to pass dirough the tube adapted to the tubulure of the re-
ceiver, and  consequendy  must pass through the water of
the first botde:   they  therefore  suffer a first  resistance,
which partly condenses them.  But as  almost all vapours
are more or less miscible and soluble in water, a calculation
is previously made of the quantity of water necessary to ab-
sorb the vapours which are disengaged from the mixture
in the retort;  and care is taken to distribute this proper
quantity of water in the bottles of the apparatus.
   By this means we obtain the purest and most concentra-
 tedproducts; because the water, which is always in the re-
ceiver, and  is the vehicle of these substances, becomes sa-
turated with  them.   There  is, perhaps, no other method
of obtaining products always of an equal energy, and com-
parable in their effects; a circumstance of the greatest im-
portance in the operations of the arts, as well as in philoso-
phical experiments.
   I have applied this apparatus to works in the large way;
and I use it to extract the common muriatic acid, the oxi-
genated muriatic acid, ammoniac or volatile alkali, &c.
   As it would very often happen, in this apparatus, that
the pressure of the external air would cause the water  of
the outer vessels  to pass into the receiver, in consequence
of the simple  refrigeration of the retort; this inconvenience
has been obviated,  by inserting a straight tube into the
necks of the first and the second botties,  to such a depth,
that its lower  end is plunged  into the water, while its other
end rises several  inches above the neck of the  botde.  It
may easily  be conceived, as  a consequence of this dispo-
sition, that when the dilated vapours of the receiver and re-
tort are condensed by cooling, the external air  will  rush 
40
WOULFE'S APPARATUS.
BALANCES, &C
through these tubes to establish the equilibrium; and wa-
ter cannot pass from the one to the other.
   Before the invention of tiiis apparatus, it was usual  to
drill  a hole in  the  receiver, which was kept closed, and
only opened from time to time for the escape of the va-
pours.  This method was inconvenient in many respects.
In the first place, and principally, because, in spite  of  all
precautions, it was attended with the risk of an explosion
every moment,  by the irregular disengagement of the va-
pours, ane\ the  impossibility of calculating the quantity
produced in a given time.   A second inconvenience was,
that the vapours which thus escaped occasioned a consi-
derable loss in the product,  and  even  weakened the  re-
mainder; because  this volatile principle consisted of the
strongest part.   A third inconvenience was, that the va-
pours which did escape incommoded the artist  to such a
degree, that it was impossible to perform most of the ope-
rations of chemistry  in the course of a lecture, where a
considerable number of auditors were present.
   Thus it  is that the apparatus of Woulfe unites a num-
ber of advantages:  on die one hand, economy in the pro-
cesses, and superiority in the product;  on the other hand,
safety for the chemist and his assistants: and  in  every
point of view the author is entitled to the best acknow-
ledgments  of chemists, who were too often  so much  af-
fected with  these unwholesome  exhalations,  that their
health was either totally destroyed,  or they fell absolute
victims to  their zeal for the promotion of science.
   It is necessary that a laboratory  should  be  provided
with balances of the utmost accuracy;  for  the chemist,
who very frequently operates only upon small quantities,
ought to be able by the strictness of his operations, ancl
the accuracy of his  apparatus, to produce results compa-
rable with those of works in the large way.  It frequently
happens that the simple essay of a specimen of an ore de-
termines the opening of a mine:  and it scarcely need be
pointed out, of how great consequence it is to remove eve-
ry cause of error from die operations of chemistry; since
the slightest error in the works of the  laboratory may be
attended with the most unhappy consequences, when the
application of the principles is made to  works in the large
wav. 
EXPLANATION OF THE PLATES.
41
   We shall treat of other vessels and of the chemical ap-
paratus, in proportion as we shall have occasion  to make
use of them;  for it appears to us that,  by thus connecting
the description with their use, we  shall succeed better in
rendering them intelligible to the reader, at the same time
that his memory  will be less fatigued.*

               * Explanation of the Plates.—Plate I.

  Tig. 1. A is a stand, made of tin, thirteen inches high, consisting
of a flat bottom, from which proceeds four upright pieces of the same
metal, one inch broad, which are riveted to the top, in which there is
a round aperture, three inches in diameter, to receive the bottom of
a retort or oil-flask.  B is one of Argand's lamps ; C a retort, luted
to a receiver D, which is supported by a frame of wood E.  The case
F, which is placed over the retort, to confine the heat of the  lamp, is
formed of two pieces of tin which include a column of  atmospheric
air  one inch thick between them.   It is ten  inches in  height; the
opening in the side is three and a half  inches, and the internal dia-
meter seven inches.
  Fig. 2.  A is a cylindrical vessel  of tin, thirteen  inches high, and
twenty-one in circumference, open at a, so as to admit a lamp, with
a round aperture in the top, three inches in diameter. B is a circular
case, four inches high,  formed of two pieces of  the  same metal,
which include a column of atmospheric air, one inch thick, at the top
and on the sides.  The lower part has an opening five inches in dia-
meter, and in the middle of the upper part,  there is an aperture  to
receive the neck of an oil flask.   C is a flask from which proceeds the
tube D, which enters the bottle E.
   In using this apparatus, the flask, containing the subject of the
operation, must be placed on the cylindrical body A.  The case B is
then to be put over the flask, and the tube D, which enters a perforated
cork, luted to it with a strip of paper,  covered with a paste  made of
flour and water.  The atmospheric air which the case B contains, is
a bad conductor of heat;  hence upon applying  an Argand lamp to
the bottom of the flask, the heat is accumulated round its sides, and
thus prevented from flying off into the air.
   Fig. 3. A is the cylindrical vessel of tin, E the case containing the
 atmospheric air, and F an oil flask, on the neck of which, the head of
 an alembic B,  made of tin or copper, seven inches high, is placed.
C, the neck of this vessel, thirteen inches long, enters an oil-flask D.
  -To use this apparatus, the flask  must be placed on the top of the
 cylindrical body A-  The vessel containing  the atmospheric air, is
 then to be placed over the flask, and the head of the alembic fixed to
 its neck.  ' G, the part over the top of the head of the alembic, must
 be filled with cold water.
   This economical apparatus may be used;
   First. In obtaining gases from  certain substances, which require
 the application of  heat; as oxygenous air,  from  manganese or red
 tead and the sulphui ic acid ; or ammoniacal gas, from lime and sal 
42
GRAVITATION  OR ATTRACTION.
                        SECTION I.

Concerning the General Law which tends to bring the Particles of
  Bodies together, and to maintain  them in a  State of Mixture or
  Combination.

      THE Supreme Being has  given a force of mutual at-
       traction to the particles of matter;  a principle which
is alone sufficient to produce that arrangement which the
bodies of this universe present to our observation.   As a


ammoniac; or oxymuriatic gas from the manganese and the marine
acid, &c
   Secondly. In making  ammoniac, and the liquid and concrete car-
bonate of ammoniac; in uniting sulphur with pot-ash, soda and lime;
to compose sulphuret of pot-ash, soda and lime ', to form fulminating
mercury, silver and gold, and the prussiates of lime, potash, Etc.
   Thirdly. In procuring several of the acids, as the nitric, muriatic,
oxymuriatic, oxalic, fluoric, acetic, &c
   Fourthly. In distilling water and spirituous  liquors to form alco-
hol, &c. and uniting the sulphuric acid and alcohol to make ether, &c
   Fifthly. In the dfying of powders, and in evaporating water, and
some of the acids from saline solutions.  A vessel of tin, copper, or
glass, or a queen's-ware saucer, may be placed on the top of either of
the stands for this purpose.
   Sixthly.  In making experiments upon all kinds of  dying drugs,
 and
   Seventhly.  In analizing earths and the ores of metals, in the hu-
 mid way.
                           Plate II.
   Fig. 1. The furnace A is formed of thick sheet iron, is ten inches
 high from the grate,  and ten inches  in  diameter.  There are  two
 holes in its sides.'to admit an earthen, iron or copper tube, and a door
 on one side to put in fuel, when a still, or any other piece of appara-
 tus, is placed on its top.  B is a brass funnel, and C  a wire of the
 same  metal,, which enters into the tube of the funnel D, which is
 screwed into the gun-barrel  E.   F is a bent tube made of glass, Jin,
 or copper, which is fixed in the mouth of the gun-barrel, and which
 enters under the shelf H, of the hydropneumatic tub G, which should
 be made of cedar, and the size of a common washing-tub, but of an
 oval form.  I is a thumb screw, to fix another shelf J to the tub.  K
 is a bell glass.
    If water or any other fluid is put in the funnel B, it may, by turn-
 ing the  wire, be made to pass drop by drop, over any substance con- 
              AFFINITY OF  AGGREGATION.          48>

 very natural consequence  of this primordial law,  it fol-
 lows that the elements of  bodies must have been urged
 towards each other;  that masses must have been formed
 by their re-union; and that solid and compact bodies must
 have insensibly been constituted; towards which,  as  to-
 wards a centre, the less heavy and  less  compact bodies
 must gravitate.
   This law of attraction,  which the chemists call Affini-
 ty, tends continually  to  bring principles  together  which
 are disunited, and retains  with more or less energy those
 which are already in  combination; so that it is impossible
 to produce any change in nature, without interrupting or
 modifying this attractive power.
   It is natural, therefore, and even indispensable, that we
 should speak  of  the law of  the affinities before 'We pro-
 ceed to treat of the methods of analysis.
   Affinity  is  exercised either between principles of the
 same nature, or between principles of a different nature.
   We may, therefore, distinguish two kinds of affinity,
 with respect to the nature of bodies.  1. The affinity of ag-
 gregation,  or that which exists between two principles of
 the same nature.   2. The affinity of composition, or that
 which  retains two or more principles of different natures in
 a state of combination.

             Of the Affinity  of Aggregation.

   Two drops of water which unite together into one, form
 an aggregate,  of  which each drop is known by the name
 of an integrant part.

 fined in the gun-barrel, and the  aerial product wUl be received in the
 bell glass K.
   Fig. 2. A is a chafing dish, a few inches larger than the common
 size, containing a gun-barrel cut in two parts, and closed at one end
 by welding.  B, a bent lube, which enters under the shelf of the hy-,
 dropneumatic box C.  D, a bell glass.
   Fig. 3. A is a subliming vessel, shaped flat like a turnip.
   Fig. 4. A is a cast iron matrass, sixteen inches in circumference, and
 a foot long, into the mouth of which the gun-barrel B is well ground,
 for making oxygen gas, carbonated hydrogen gas, oxyd of carbon, &c.
   Fig. 5. A is an eight ounce vial, into the mouth of which the bent
tube B enters, for making hydrogen gas, nitrous air, carbonic acid
 £as, kc—Am. Ed. 
44
AFFINITY OF AGGREGATION.
  An aggregate differs from a heap; because the inte-
grant parts  of this last have no perceptible adhesion to
each other;  as for example, a heap of barley, of sand, &c.
  An aggregate and a heap differ from  a mixture;   be-
cause the constituent parts of this last are of a different na-
ture; as, for example, in gunpowder.
  The affinity of aggregation is stronger, the nearer the
integrant parts approach to  each other;  so that every
thing which tends to separate  or  remove  these integrant
parts from each otiier, diminishes their affinity, and weak-
ens their force of cohesion.
  Heat  produces  this effect  upon  most known bodies;
hence it is that melted metals have no consistence.   The
caloric, or matter of heat,  by combining with bodies, al-
most always produces an effect opposite to the force of at-
traction;  and we  might consider ourselves as authorized
to affirm that it is a principle of repulsion, if sound che-
mistry had not proved that it produces this effect  only by
its endeavour to combine with bodies, and thereby neces-
sarily diminishing their force of aggregation, as all other
chemical ?gents do.  Besides which, the  extreme levity
of caloric produces the effect  that,  when it  is combined
with any given body, it continually tends to elevate it, and
to overcome that force which retains  it, and precipitates it
towards the earth.
  The mechanical operations of pounding, of hammering,
or of cutting, likewise diminish the affinity of aggregation.
They remove the integrant  parts to  a distance  from each
other: and this new disposition, by presenting  a  less de-
gree of adhesion, and a larger surface, facilitates the imme-
diate action, and augments the energy of chemical agents.
It is for this purpose that bodies  are divided when  they
are  to be analized, an&that the effect of re-agents  is facili-
tated by the action of heat.
  The mechanical  division  of bodies is  more difficult,
the  stronger their aggregation.
  Aggregates exist under different states; they are solid,
liquid, aeriform, &c.—See Fourcroy's Chemistry. 
AFFINITY  OF COMPOSITION-
45
            Of the Affinity of Composition,,

  Bodies of different kinds  exert a tendency  or attrac-
tion upon each other, which is more or less strong; and
it is by virtue of this force that all the changes of com-
position or  decomposition  observed amongst  them, are
effected.
  The affinity of composition exhibits invariable laws in
all the phenomena it causes.   We may  state these  laws
as general principles; to  which may be referred all the
effects presented to our observation by the action of bo-
dies upon each other.
  I.  The affinity of composition  acts only between the
constituent parts of bodies.
   The general law of attraction is exerted upon  the mass-
es ; and in this respect it differs from the law of the affi-
nities, which does not perceptibly  act but on the elemen-
tary  particles  of bodies.   Two bodies  placed near each
other do not unite; but,  if  they be divided and mixed,
a combination may arise.   We have examples of this
when the muriate of soda, or common salt, is  triturated
with litharge;  the muriate of ammoniac, or common sal
ammoniac, with lime, &c. And it may be asserted that the
energy of  the  affinity  of composition is almost always
proportioned to the  degree of the division of bodies.
   II. The affinity of composition is in the  inverse ratio
of the affinity of  aggregation.
  It is  so much the more difficult to decompose a body,
as its constituent principles are united or retained by a
greater force.  Gases, and especially vapours, continually
tend to combination, because their aggregation is weak:
and  nature, which is  constantiy  renewing the produc-
tions of this universe, never combines solid with solid ;
but,  reducing every thing into the form of gas, by this
means breaks the impediments of aggregation;  and these
gases uniting together,  form solids in their turn.
  Hence, no doubt, it arises, that  the  affinity of com-
position is so much the  more strong as bodies approach
nearer  to the  elementary state ; and we shall observe on
this subject, that this law of nature  is founded in wis-
dom ; for if the  force  or affinity of composition did not 
46
AFFINITY  OF COMPOSITION".
 increase in proportion as bodies were brought to this de-
 gree of simplicity ;  if bodies did not assume a decided ten*
 dency to unite and combine, in proportion as they approach
 to their primitive or elementary state; the mass of elements
 would continually increase by these successive and unin-
 terrupted decompositions;  and we should insensibly re-
 turn again to that chaos or confusion of principles, which
 is supposed to have been the original state of this globe.
   The necessity of this state of division, which is  so
 proper to increase the force of affinity,  has caused  it to
 be admitted as an incontestible principle, that the affinity
 of composition does not take place, unless one of the bo-
 dies be in the fluid  state : corpora non agunt nisi sint fiu-
 ida.   But it seems  to me that extreme division might be
 substituted instead of dissolution; for both these opera-
 tions tend only to attenuate bodies, without altering their
 nature.  It is by virtue of this division, which is equi-
 valent to dissolution, that the decomposition of muriate
 of soda is effected by trituration with minium, as well as
 the union of cold and dry alkali with antimony, and the
 disengagement of volatile alkali by the simple mixture of
 sal ammoniac with lime.
  III. When two or more bodies unite by the affinity of
 composition, their temperature changes.
  This phenomenon cannot be explained but by consi-
 dering the fluid  of heat as a constituent principle of bo-
 dies, unequally distributed amongst them ;  so that, when
 any  change is produced in bodies,  this fluid is displaced
 in its turn, which necessarily produces a change of tem-
 perature.   We shall return to these principles when we
■speak of heat.
  IV. The compound which results from  the combina-
 tion  of two bodies, possesses properties totally different
 from those of its constituent principles.
  Some chemists have  affirmed,  that the properties  of
 compounds were intermediate  between those of their con-
 stituent parts.   But  this term " intermediate" has no
 meaning in the present case; for what intermediate qua-
 lities can exist between sour and sweet, or between wa-
 ter and fire "?
  If we attend ever so little to the phenomena which are
 exhibited to us by bodies in their  composition, we glial! 
          THE LAWS OF  DECOMPOSITION.        "47

perceive that their form, their taste, and their consistence,
are changed in combination;  and we cannot establish any
rule  to indicate,  a priori, all the  changes which may
arise, and the nature and  properties of the body which
shall be formed.
  V. Every  individual substance has its  peculiar  affi-
nities with the various substances presented to it.
  If all bodies had the same  degree of affinity with each
other,  no change could take place  amongst  them: we
should not be able to displace any principle by presenting
one  body to  another.   Nature has therefore   wisely
varied the affinities, and appointed to each body its rela-
tion with all those that can be presented to it.
  It is in consequence of this difference  in the affinities
that all chemical decompositions are effected; all the ope-
rations of nature and art are founded upon it.  It is there-
fore of importance to be well acquainted with all the phe-
nomena and circumstances which this law of decomposi-
tion can present to us.
   The affinity of composition has  received, different
names, according to its effects.  It is divided into simple
affinity, double affinity, the  affinity  of an  intermedium,
reciprocal affinity,  &c.
   1. Two principles united  together,  and separated by
means of a third,  afford  an example of simple affinity:
it consists in the displacing of one principle  by  the ad-
dition of a third.   Bergman  has given it the name  of
Electrive Attraction.
   The body which is disengaged, or displaced, is known
by the name of the Precipitate.  An alkali precipitates-
metals from their  solutions;  the sulphuric acid  precipi-
tates the muriatic, the nitric, &c.
   The precipitate is not always formed by the disengaged
substance.   Sometimes the new compound itself is pre-
cipitated ; as, for example, when I pour the sulphuric or
vitriolic acid on a  solution of muriate of lime.   Some-
times the disengaged body and the new compound are
precipitated  together;  as,  for example, when the sul-
phate  of magnesia or Epsom salt is dissolved in water,
and precipitated by means of .lime-water.
   2. It often happens that the compound of two princi-
 ples cannot be destroyed  either by  a third or a fourth 
48         Various  cases of  affinity.
 body separately  applied;  but  if these two bodies be
 united, and placed in contact with the same compound,
 a decomposition or  change of principles will then take
 place.  This phenomenon constitutes the double affinity.
 An example will render this proposition more clear and
 precise.  The sulphate of pot-ash or vitriolated tartar is
 not completely decomposed by the nitric acid or by lime,
 when either of these principles  is separately presented;
 but, if  the nitric acid be combined with lime, this nitrate
 of lime will decompose the sulphate of pot-ash.   In this
 last case the affinity of  the sulphuric acid with the alkali
 is weakened by its affinity to the lime.   This acid, there-
 fore, is subject to two attractions; the one which retains
 it to the alkali, and the otiier which attracts it  towards
 the lime : Mr. Kirwan has named the first the Quiescent
 Affinity, and the other the Divellent Affinity.   The same
 may be said respecting the  affinities  of the alkali;  it is
 retained to the sulphuric acid by  a superior  force, but ne-
 vertheless attracted by the nitric  acid.  Let us suppose,
 now, that  the sulphuric acid adheres to the alkali with a
 force as 8, and  to  the lime by  a force expressed by the
 number 6 ;  that die nitric acid adheres to the lime by a
 force as 4,  and tends to unite with the alkali by  a force
 as 7.  It may then be perceived  that the nitric acid and
 the lime, separately applied to the sulphate  of pot-ash,
 would not produce any change:  but if they be presented
 in a state of combination, tiien the sulphuric  acid is at-
 tracted on the one hand by 6, and retained  by 8 ; it has-
 therefore an effective attraction to the alkali  as  2.   On
 the other hand,  the nitric acid is  attracted by a force  as
 7, and retained by a force  as 4; it  therefore retains a
 tendency to unite  with the alkali, which is denoted by
 the number 3 ; and  consequently it ought to displace die
 sulphuric acid, which is retained only by a  force as 2.
   3.  There are cases in  which  two  bodies, having no
perceptible affinity to each other,  obtain a disposition  to
 unite by the intervention of a third; and  this is called
the affinity of an intermedium.  An alkali ic the interme-
dium of union between oil and water; hence die theory
 of lixiviums,  of washings,  &c.
   If the affinities of bodies were well known, we might
 foretel the  results of all operations:   but  it  is obvious 
REGULAR FIGURES  OF BODIES.
49
how difficult it must be to acquire  this extensive know-
ledge of nature ;  more especially since modern discove-
ries have exhibited to us an affinity  of modifications in
our  processes, and have  shewn that results may  vary
with such  facility,  that even  the absence or presence of
light will render them very different.
  As long  as chemistry was confined to the knowledge
of a few substances, and was busied only in attending to
a certain number of facts, it was possible to draw up ta-
bles of affinity, and to exhibit the result of our know-
ledge in one and the same table.  But all the principles
upon which these tables have been constructed, have re-
ceived modifications; the number of principles has in-
creased ; and we find ourselves under the necessity of la-
bouring upon new ground.  A sketch of this great work
may be seen in the Essay on Affinities of the celebrated
Bergman, and in article Affinity in the Encyclopedic Me-
thodique.
   VI.  The  particles  which  are  brought together and
united by affinity, whether they be of the same nature or
of different natures, continually tend to form bodies of a
polyhedral, constant, and determinate  form.
   This beautiful law of nature,  by wjhich she impresses
on all her productions a constant and regular form, ap-
pears to have been  unknown to the ancients : and when
chemists began to discover that almost all bodies of the
mineral kingdom affected regular forms, they at first dis-
tinguished them according to the inaccurate resemblance
supposed to exist between them and other known bodies.
Hence the  denomination of crystals in pyramids, needles,
points of diamonds, crosses,  sword blades,  &c.
   We are  more particularly  indebted to the  celebrated
Linnaeus for the first  precise ideas of these geometrical
figures.  He took notice of the constancy and uniformity
of this character;  and this celebrated naturalist thought
himself authorized tb make it the basis of his method of
classification of the mineral kingdom.
   Mr. Rome de Lisle has proceeded  still farther : he has
subjected all the forms to a strict  examination; he  has,
as  it were, decomposed them; and is of opinion that he
can distinguish in the crystals of all analogous or identi-
cal substances, the simple modifications and shades of a
                         G 
5f>         REGULAR FIGURES OF BODIES

primitive  form.  By this  means  he has reduced all the
confused and irregular forms to certain primitive figures;
and  has attributed to nature a plan or primitive design,
which she varies and modifies in a thousand manners, ac-
cording to circumstances  that influence  her proceedings.
This truly great and philosophical work has rendered this
part  of mineralogy in the highest degree  interesting ; and
if we should admit that Mr. De Lisle has perhaps car-
ried  these resemblances too far,  we cannot but allow that
he deserves a  distinguished place amongst those authors
who have contributed to the progress of  science.   The
Crystallographie of this celebrated naturalist may be  pe-
rused with advantage.
   The  abbe Hauy has since applied calculation to obser-
vation.  He has undertaken to  prove that each crystal
has a nucleus or primitive form;  and has shewn the laws
of diminution to which the compotent lamina? of the cry-
stals are subject,  in their transition from the primitive to
the secondary  forms.  The development of these fine
principles, and  their application to crystals the best known,
may be seen in his  theory of the  structure  of crystals,
and  in  several  of his memoirs printed in the  volumes of
the Academy of Sciences.
   The united labours of these celebrated naturalists have
carried crystallography to a degree of perfection of which
it did not appear susceptible.  But we shall,  at this mo-
ment, attend only  to the  principles  according to which
crystallization is effected.
   To dispose a substance to crystallization,  it is neces-
sary  in the  first  place to reduce it to the most complete
state of division.
   This division may be  effected by solution, or by  an
operation purely mechanical.
   Solution may be effected either by  the means of water
or of fire.   The solution of salts is in general performed
in the first liquid, that of metals  is effected by means of
the second;-  and their solution is not complete until a de-
gree of  heat is applied of  sufficient  intensity to convert
them into the state of gas.
   When the water which  holds any salt  in  solution is
evaporated, the principles of the  dissolved body are insen-
sibly brought nearer to each other, and it is  obtained in 
           PRODUCED BY CRYSTALLIZATION.        51

  regular form.   The  same circumstance nearly takes place
  in die solution by  fire.  When  a metal  is impregnated
  with this fluid, it does not crystallize but in proportion as
  this excess of igneous fluid is withdrawn.
    In order that the form of a crystal may be regular, three
  circumstances are  required; time, a sufficient space, and
  repose.   Consult Linnaeus, Daubenton, &c.
    A. Time causes the  superabundant fluid to be slowly
  dissipated,  and brings the integral parts nearer each other
  by insensible gradation, and  without any sudden shock.
  These integrant parts therefore unite according  to their
  constant laws, and form a regular crystal.  For this rea-
  son it is,  that slow evaporation is recommended by  all
  good chemists.  Vide Stahl's Treatise on salts, chap. 29.
    In proportion as the evaporation of the solvent is effect-
  ed, the principles  of the  dissolved body  approach each
  other, and  their affinity is continually  augmented while
  that of the solvent remains unaltered.  Hence it arises,
  no doubt, that the last portions  of the solvent are most
  difficuldy volatilized, and that salts retain a greater or less
  quantity, which forms their water of crystallization. The
  proportion  of water of .crystallization not only varies great -
- ly in the  different salts, but it adheres, with greater or less
  strength.   There  are some which suffer this water to fly
  off when  they are exposed to the air;  such as  soda or the
  mineral alkali, the  sulphate of soda or Glauber's salt, &6.
  In this situation these salts lose  their transparency, and
  fall  into  powder:  they are then said to have  effloresced.
  There are other salts which obstinately  retain  their water
  of crystallization;  such  as the muriate of pot-ash, the ni-
  trate of pot-ash or  common nitre, &c.
    The phenomena presented to us by the different salts,
  when forcibly deprived of their  water of crystallization,
  exhibit other varieties.  Some crackle with the heat, and
  are thrown  about in small pieces when the water is dissi-
  pated ;  this appearance  is  called decrepitation.  Others
  emit the same  water in the form of steam, and are lique-
  fied with  a  diminution of their bulk.  Others again swell
  up, and become converted into a blistered or porous sub-
  stance. 
52
VARIOUS APPEARANCES
  We are indebted to Mr.  Kirwan for an accurate table
of the water of crystallization contained in each salt.   This
table may be seen by consulting his Mineralogy.
  The simple cooling of the fluid which holds the salt in
solution may precipitate  a considerable  quantity.   The
caloric and the water dissolve a greater  quantity  of salt
when their action is united;   and it may easily be ima-
gined that the subtraction of one of the solvents must oc-
casion the precipitation of that portion which it held in so-
lution.  Thus it is that warm water saturated witii salt,
must suffer a part  to  precipitate by cooling; and for this
reason crystallization always begins at the surface of the
liquid, and on the sides of the containing vessel; namely,
because these parts are the first which suffer refrigeration.
  It is the alternation of heat and cold which causes the at-
mosphere to dissolve  sometimes a greater, and sometimes
a less quantity of water; and constitutes mists, the even-
ing dew, &c.
  The mutual approach of the constituent parts of a body
held in solution may be likewise accelerated by presenting
to the water which suspends  them, another  body  which
has a stronger affinity to it.   It is upon this principle that
alcohol precipitates several salts.
  B. Space or sufficient room is likewise a condition neces-
sary for obtaining regular crystallization.   If nature be re-
strained in her operations, the product of her labour will
exhibit symptoms of this state of constraint.   It may be
asserted that nature forms her productions according to all
the circumstances which may influence her operations.
  C.  A state of repose in the fluid is likewise necessary
to obtain very regular forms.  Uninterrupted agitation op-
poses all symmetrical arrangement; and in this case the
crystallization obtained will be  confused and  indetermi-
nate.
  I am persuaded, that, in order to obtain bodies under the
form of crystals, a previous solution is not necessary, but
that a simple mechanical division would  be sufficient. To
obtain a conviction of this truth, it is only necessary to ob-
serve that solution does not change the nature of  bodies,
but simply procures an extreme state of division;  so that
the disunited principles approaching each other very gra-
dually and  without starts, can adapt themselves to each 
         ATTENDING CRYSTALLIZATION, &.C       53

other, by following the invariable laws of their gravity and
affinity.   Now a division purely mechanical produces the
same effect, and places the principles in the same disposi-
tion.  We ought not therefore to be  surprised if most
salts, such as gypsum, when dispersed in the earth, should
assume regular forms without any previous solution; nei-
ther ought we to think it strange if the imperceptible frag-
ments of quartz, of spar, &c. when carried along and pro-
digiously divided by the action  of waters, should be de-
posited in the form of regular crystals.
  A very singular property may be  observed  in salts;
which may be referred to crystallization,  but is likewise
in some measure remote from it, because it does not de-
pend upon the same causes.  This is the property of ris-
ing along the sides of the vessels which contain the solu-
tion.  It is known by the name of Saline Vegetation.
  I have first demonstrated that this phenomenon depends
on the concurrence of air and light;  and that the effect
may be  determined at  pleasure towards any part of the
vessel, by managing and directing the action of these two
agents.
  I have shewn the principal forms which this singular
vegetation affects.  The detail of my experiments may
be seen in the third volume of the Memoirs of the Aca-
demy of Toulouse.
  Mr. Dorthes has confirmed my results;  and has more-
over observed that camphor, spirits of wine, water, &c.
which rise by insensible evaporation in half-filled  vessels,
constantly attach themselves to the most enlightened parts
of the vessels.
  Messrs. Petit and Rouelle have treated on the  vegeta-
tion of salts; but a series of experiments  on the subject
was wanting.   This is  what  we  have  endeavoured to
supply. 
54
METHODS OF SEPARATING
                     SECTION II.

Concerning the various Means employed by Chemists to overcome
    the Adhesion which exists between the Particles of Bodies.

     THE law of affinities, towards which our attention has
       been directed,  tends continually to bring the parti-
cles of body into contact, and to maintain them in their
state of union.   The efforts of the chemist are almost all
directed to overcome this attractive power, and the means
he employs are reducible to—1.  The division  of bodies
by  mechanical operations.  2.  The division or separation
of  the particles from  each other by the assistance of sol-
vents.   3. The means of presenting to the several princi-
ples of the same bodies, substances which have a stronger
affinity to them than those principles have to each other.
  I. The different operations performed upon bodies by
the chemist, to determine their nature, alter their form,
their texture, and even  in some instances  change their
constitution.  All these  changes are either mechanical or
chemical.
  The mechanical operations we shall at present describe,
do not change die  nature of  substances, but  in general
change only their form and bulk.  These operations are
performed by  the hammer,  the knife,  the  pesde,  he.
"Whence it follows that the chemical laboratory ought to
be provided with all these instruments.
  These divisions or triturations are  performed in mor-
tal's of stone, of glass, or of metal.   It is the  nature of
the substance under examination which determines the
use of one or the  other of these  vessels.
  The object of these preliminary operations is,  to  pre-
pare and dispose bodies  for new  operations which may
disunite their principles  and  change  their nature; these
last-mentioned  operations, which may be  distinguished
by  the appellation Chemical,  are what  most essentially
constitute the analysis.
  II.   The  solution to which we are at present to attend,
consists  in  die division and disappearance of a solid in « 
         THE  COMPONENT  PARTS OF  BODIES.      55

liquid, but without  any alteration in the nature of the
body so dissolved.
  The liquid in which the solid disappears, 'is .called the
solvent or menstruum.
  The agent of solution appears to follow certain  con-
stant laws, which we shall here point out.
  A. The agent of  solution does not appear  to  differ
from that of affinity;  and in  all cases the solution is more
or less abundant,  the greater the affinity of the  integrant
parts of the solvent  is to those of the body  to be dis-
solved.
  From this  principle it follows, that to  facilitate solu-
tion, it is necessary that bodies should be triturated and
divided.   By this means a  greater  number of surfaces
are  presented, and the affinity of die  integrant parts is di-
minished.
  It sometimes happens that the affinity between the sol-
vent and the  body presented to it has so little energy that
it does not become perceptible till after a considerable in-
terval  of time.  These slow operations,  of  which we
have some examples  in our  laboratories, are common  in
the works of nature ;  and it is probably to similar causes
that we ought to refer most  of those  results whose causes
or agents escape our perception or observation.  -
  B. Solution is more speedy in proportion as die body
to be dissolved presents a greater surface : on this prin-
ciple is founded the practice of pounding,  triturating, and
dividing  bodies intended to  be dissolved.   Bergman has
even observed, that bodies which  are not attacked  in
considerable  masses,  become soluble after  minute divi-
sion.   Letters on Iceland, p. 421*.
  C. The solution of a body constantiy  produces' cold.
Advantage has even been taken  of  this phenomenon  to
procure artificial cold, much superior to the most rigor-
ous  temperature  ever observed  in  our  climates.   We
shall again advert to  this principle when we come to treat
of the laws of heat.
  The principal solvents employed in our operations are
water, alcohol, and fire.  Bodies submitted to one or the
odier of diese solvents present similar phenomena;  they

  *  Von Troil's Letters, quoted by Mr. Bergman.  T. 
56
PHENOMENA OF  SOLUTION.
are divided, rarefied, and at last disappear:  the most  re-
fractory metal melts, is dissipated in vapour, and  passes
to the state of gas,  if a very strong heat be applied to it.
This last state forms a complete  solution of the metallic
substance in the caloric.
   The effect of caloric is often  united with one  of  the
other solvents,  to accomplish a more speedy  and abun-
dant solution.
   The  three  solvents here  mentioned  do  not  exer-
cise an  equal  action on  all  bodies indiscriminately.
Skilful chemists have exhibited  tables  of the dissolving
power of these menstruums.   We may see, in the Mine-
ralogy of  Kirwan, with what care that celebrated chemist
has exhibited the degree  of solubility of each salt in wa-
ter.  The  table  of Mr.  De  Morveau  may likewise be
consulted on the dissolving power of alcohol.  Journal de
Physique, 1785.
   Most authors who have treated of solution have consi-
dered it in too mechanical a point  of view.  Some have
supposed sheaths in the solvent,  and points in  the body
dissolved.  This absurd  and  gratuitous supposition  has
appeared sufficient  to  account  for  the  action  of acids
upon bodies.  Newton and Gassendi have admitted pores
in water, in which salts might insinuate themselves; and
have by this means explained why water does not augment
in its bulk in proportion to the quantity of salt it takes up.
Gassendi has even supposed pores of different forms; and
has endeavoured to shew by this means how water satu-
rated with one salt may dissolve others of another kind.
Dr. Watson, who has observed  the phenomena of solu-
tion with the greatest care, has  concluded  from his  nu-
merous experiments;  1.  That the water rises  in the ves-
sel at the moment of the immersion of the  salt.  2. That
it falls during the solution.  3. That it rises after the so-
lution above the original  level.   The two last effects seem
to me to arise from the change of temperature which the
liquor undergoes.  The refrigeration arising from the so-
lution must diminish the  volume of the solvent;  but it
ought to return to its first state as soon as the  dissolution
is  finished.  The tables of Dr. Watson  respecting these
phenomena, and the specific  gravity of water  saturated 
EFFECTS OF RE-AGENTS.
57
 with different salts, may be consulted in  the  Journal  de
 Physique, vol. xiii. p. 62.*
    III. As the peculiar affinities of bodies to each other
 are various, the constituent principles may be easily disen-
 gaged by other substances; and it is upon this considera-
 tion that the action of all the re-agents employed by che-
 mistry in its anal} sis is founded.   Sometimes the chemist
 displaces certain principles, which he can in diat state exa-
 mine more accurately, because insulated,  and disengaged
 from all  their combinations.   It frqjaently happens that
' the re-agent made use of combines with some principle of
 the body analized;  and a compound arises, whose charac-
 ters indicate to us the nature of the principle which  has
 thus entered into combination, because the combinations
 of the  principal re-agents with various bases are well
 known.   It likewise frequently happens that the re-agent
 made use  of is itself decomposed,  which circumstance
 renders  the phenomena and the products more complicat-
 ed ; but we are enabled from the nature of these products
  to form a judgment of the component parts of the body
 analized.   This last fact was little attended to by the an-
 cient chemists;  and this is one of the principal defects of
 the labours of Stahl, who has referred most of those phe-
 nomena to the  bodies which he  submitted  to analysis,
  which in reality arose only from the decomposition of the
  re--agents employed in his operations.
                    SECTION III.

Concerning the  Method of Proceeding which the Chemist ought
  to follow in the Study of the various Bodies presented to us by
  Nature.

     THE  progress made in any science depends upon the
      solidity  of those principles which form its basis, and
•upon the method of studying them.   It is not, therefore,

        * Or in the fifth vol. of his Chemical Essays.  T-
H 
SB
METHOD OF STUDYING
to be wondered at, that chemistry made but little progress
in those times, when the language of chemists was enig-
matical, and when the principles of the science were found-
ed only on analogies falsely deduced,  or on a  few facts
illy understood.   In the times which have followed this
epocha, the facts have indeed been more attended to;,  but,
instead of suffering them to speak for themselves chemists
have been desirous of  making applications, drawing con-
sequences, and establishing theories.   Thus it was that
Stahl,  when he first observed that oil of vitriol  and char-
coal produced sulphur, if he had then confined himself to
the simple relation of the fact,  he would have announced
a valuable and eternal truth;  but when he concluded that
the sulphur was produced by the combination of the in-
flammable principle of the charcoal with the oil of vitriol,
he asserted that which the experiment does not point out:
then it was that he proceeded further than  the  facts war-
ranted; and this  first rash step  might be a first step to-
wards error.   All doctrine,  in order to be lasting, ought
to consist of the pure and simple expression of facts: but
we are almost always  governed by our imaginations; we
adapt  the facts to our manner of seeing them, and thus we
are misled by ourselves.  The prejudice of self-love after-
wards furnishes us with various means to  avoid recanta-
tion ;  we exert ourselves to draw our successors into the
same paths of error; and it is not till after much time has
been lost, after many vain conjectures have been exhibit-
ed,  and after we have the strongest convictions that it is
impossible to bend the nature of things to our caprices and
unfounded ideas, that some superior mind disengages it-
 self from the delusion;  and returning to experiment, and
the nature of things, suffers himself to be led  no further
 than he is authorized by these  to proceed.
   We may affirm, to  the honour of  our  cotemporaries,
 that facts are at present discussed by a much  severer lo-
 gic; and it is to  this vigorous method of investigation and
 discussion that we are indebted for the rapid progress of
 chemistry.   It is in consequence of this  dialectic march
 that we have at length arrived to the practice of attending
 to all  the principles which are combined or disengaged in
 the operations of nature and art.  We keep an account 
THE SCIENCE OF CHEMISTRY.
50
-of all the circumstances which have a more or less conside*
rable influence on the results, and we deduce simple and na-
tural consequences from the whole of the facts; by which
means we create a science  as strict in  its principles,  as
sublime in its applications.
   This then is the moment to draw out a faithful sketch
of the actual state of chemistry, and to collect in the nu-
merous writings of modern chemists every thing which
may serve to lay the foundation of this beautiful science.
   Not many years  ago,  it was possible to present,  in a
few words, the whole of our  knowledge of chemistry.   It
was sufficient, at that time, to  point out the  methods of
performing pharmaceutical operations;  the processes of
the  arts were almost all enveloped in darkness, the pheno-
mena of nature were all enigmatical; and it is only since
this veil has begun to be  removed that we have beheld
the  development of a collection of facts and researches
referable to general principles, and forming a  science en-
tirely new.  Then it was that a number of men of genius
 reviewed the whole,  and attended to the  improvement of
 chemical knowledge.  Every step in their progress brought
 them nearer to the truth; and in a few years we have be.
held a perspicuous doctrine arise out of the ancient chaos.
Every event  has appeared conformable to the laws they
established; and the phenomena of art and nature are now
 explained with equal facility.
   But in order  to advance with speed in the career which
 has been thus opened,  it  is  necessary  to explain certain
 principles, according to which we may  direct  our steps.
   In the first place I think it proper to avoid  that tedious
 custom which subjects the beginner in any science to the
 painful task of collecting all the opinions of various philo-
 sophers before he decides for himself.  In reality, facts be-
 long to all times, and are as  unchangeable as  nature her-
 self, whose language they  are.   But the consequences de-
 duced from them must vary according to the  state of our
 acquired knowledge.  It  is eternally  true for  example,
 that the combustion of sulphur affords the sulphuric acid.
 It was believed, for a certain time, that this acid was con-
 tained in the sulphur; but our discoveries on the combus-
 tion of bodies ought to have led us to the deduction of a 
* 60              METHOD OF  STUDYING

 very different dieory from that which presented itself to
 the" earlier chemists.   We ought, therefore, to attach our-
 selves principally to facts;  or rather we  ought to attach
 ourselves to the  facts only, because the explanation which
 is given of them at remote times is very seldom suited to
 the present state of our knowledge.
   The numerous facts with which  chemistry has been
 successively enriched, form the first embarrassment of the
 student who is desirous of acquiring the elements of this
 science. In fact, what are the elements of a science ?  The
 clear, simple, and accurate  enunciation of those truths
 which form its basis.   It  is  necessary, therefore, for the
 full accomplishment of this purpose, to analize all the facts
 and to exhibit a faithful and clear abridgment:  but this
 method is impracticable on account of the numerous de-
 tails, and the infinite number of discussions, into which it
 would lead us.  The only proceeding, therefore, which
 appears to me to be practicable, is to exhibit the most de-
 cisive experiments, those which are  the least contested,
 and to neglect those which are doubtful or inconclusive:
 for one experiment, well made, establishes a  truth as in-
 contestably as a  thousand equally averred.
    "When a proposition is found to be supported by suspi-
 cious or contested facts, when opposite theories are  built
 upon contradictory experiments,  we  must have the cou-
 rage  to discuss them,  to repeat them,  and to acquire a
 certainty of die truth by our own endeavours.   But when
 this method of conviction  is out of  our power, we ought
 to weigh the degree of  confidence which the defenders of
 the opposite facts are  entitled to;  to examine  whether
 analogous facts do not lead us to adopt certain results; af-
 ter which it becomes us to give our opinion with that mo-
 desty and circumspection, suitable  to the  greater or less
 degree of probability annexed to each opinion.
    But when any doctrine appears to  us to be established
 on experiments  of sufficient validity, it then remains to be
 applied to the phenomena of nature and art.  This, in my
 opinion, is the most certain touchstone to distinguish true
 principles from those which are without foundation.  And
 when I observe  that all the phenomena  of nature  unite,
 and conform tiiemselves, as it were, to any theory, I con-
 clude that this theory is the expression  and the language of 
THE SCIENCE OF CHEMISTRY.
61
truth. WTien, for example, I behold that a plant can be sup-
ported by pure water alone, that metals are calcinable by wa-
ter, that acids are formed in the bowels  of the earth, have
I not a right to conclude that the water is decomposed ?
and do not the chemical facts which in our laboratories af-
ford a testimony of its  decomposition—do not these ac-
quire a new force by the observation of the preceding phe-
nomena?   I  conclude,  therefore, tiiat we ought to make
a point of uniting these two kinds of proofs:  and a prin-
ciple deduced from experiment is not, in my opinion, de-
monstrable until I see that it may with  facility be applied
to the phenomena of art and nature.  Hence, if I find my-
self in a state  of hesitation between opposite systems, I
will decide in favour of that whose principles and experi-
ments adapt themselves naturally, and without force to the
greatest number of phenomena.   I will always  distrust a
6ingle fact, which is applicable to no conclusion;  and I
will consider it as false, if it be in opposition to the pheno-
mena which nature presents to us.
   It appears to me likewise that he who professes to study,
or even to teach chemistry, ought not to endeavour to ar-
rive at or exhibit the whole which has been done in each
department, or to follow the tedious progress of the human
mind from the origin of a discovery to the present time.
This fastidious erudition  is fatiguing to the learner; and
these digressions ought in no  case to be admitted  in  the
enunciation of science, excepting when the historical de-
tails afford interesting facts, or lead us by uninterrupted
degrees to the present state of our knowledge.   It rarely
happens, however,  that this kind of researches,  this gene-
alogy of science, affords us such characters;  and it ought
no more to be admitted,  in general, that an elementary
\\Titer should bring together and discuss every thing which
has been done in a science, than that he who undertakes
to direct  a traveller should previously enter into a long
dissertation on all the roads which have been successively
made, and on those which still  exist,  before  he  should
 point out the best and shortest way to arrive at  the end of
 his journey.   It may, perhaps, be said of the  history of
 science, and more  especially that of chemistry,  that it re-
 sembles the  histories of nations.  It seldom affords  any
 light respecting the present situation of affairs; exhibits 
62
METHOD OF STUDYING
many fables concerning past  times;  induces a necessity
of entering into discussions  upon the circumstances that
pass in review; and supposes a mass of extraneous know-
ledge acquired on the part of the reader, which  is  inde-
pendent of the purpose aimed at in die study of  the ele-
ments of chemistry.
  When these general principles, respecting the study of
chemistry,  are once well established, we may afterwards
proceed in the chemical examination  of bodies in two
ways: we  may  either  proceed  from the simple to  the
compound, or we may descend from  the  compound to
the simple.   Both these methods have  their inconveni-
ences ; but the greatest, no doubt, which is found in  fol-
lowing the  first method is, that,  by beginning with  the
simplest bodies, we present substances to the considera-
tion of the learner which nature very seldom exhibits in
such a state of nakedness  and simplicity; and  we  are
forced to  conceal  the series of operations which have
been employed to divest these substances from their com-
binations,  and reduce them to the elementary  state.   On
the other hand, if  we present bodies to the view of  the
learner such as they are, it is difficult  to succeed in an
accurate knowledge of them; because their mutual  ac-
tion, and in general most of their phenomena, cannot be
understood without the previous and accurate knowledge
of their constituent principles, since it is upon these alone
that they depend
  After having maturely considered the advantages and
inconveniences of each method, we give the  preference to
the first.   We shall therefore begin by  giving an account
of the several bodies  in their most elementary state, or
reduced to  that term beyond which analysis can effect  no-
thing ; and, when we shall have explained their  various
properties,  we will combine these bodies with each other,
which will afford a class of simple compounds : and hence
we shall rise by degrees to the knowledge of bodies, and
the most complicated phenomena.  We shall be careful,
in any examination of the several  bodies  to which  we
shall direct our researches, to proceed from  known to  un-
known ; and  our first attention  shall  be directed to ele-
mentary substances.   But as it is impossible,  at one and
die same time, to treat of all those substances which  die 
THE SCIENCE  OF
CHEMISTRY,
63
present state of our knowledge obliges us to consider as
elementary,  we shall confine ourselves to the  exhibition
of such as are of the greatest importance in the  pheno-
mena of the globe we inhabit,  such  as are almost uni-
versally spread over its surface, and such as enter as prin-
ciples  into  the  composition of the re-agents most fre-
quently employed in our operations;  such, in a word, as
we continually find in the examination and analysis of the
component parts of the globe.   Light, heat, sulphur, and
carbone are  of this number.  Light modifies all our ope-
rations, and  most powerfully contributes to the produc-
tion of all the phenomena  which  appertain  to  bodies  ei-
ther living or inanimate.  Heat, distributed after an une-
qual proportion among all  the bodies  of this universe,
establishes their various degrees of consistence and fixity;
and is one of the great means which art and nature em-
ploy to divide and volatilize bodies, to weaken their force
or adhesion, and by that means prepare them for analysis-
Sulphur exists in the products of the three  kingdoms; it
forms the radical of one of the best known, and most ge-
nerally employed, acids;  it exhibits interesting combina-
tions with most simple substances;  and, under these  se-
veral points of view, it is one of die substances the most
necessary to be known in  the first steps of chemical sci-
ence.   The same may be said of carbone; it is the most
abundant fixed product founcl in vegetables and animals.
Analysis has discovered it  in some  mineral substances.
Its combination with oxigene is  so common  in bodies,
and in the  operations of art and nature,  that there  are
scarcely any phenomena which do not present it  to our
view, and  which consequently require the knowledge of
its properties.  From all these reasons it appears to us,
that for the  advancement of chemistry it is necessary our
first proceeding should be founded on the knowledge of
these  substances: and that we should not direct our at-
tention to other simple or elementary substances,  accord-
 ingly as they present themselves. 
64         OF ELEMENTARY SUBSTANCES.
                    SECTION IV.

         Concerning Simple or Elementary Substances.

   IF we cast an eye over the systems which  have been
    successively formed by  philosophers relative  to the
number and nature of the elements, we  shall be astonish-
ed  at the prodigious variety which prevails in their man-
ner of thinking.  In the earlier times,, every  one  seems
to have taken his own imagination for his guide ;  and we
find no reasonable system  until the time when Aristotie
and Empedocles  acknowledged as elements, Air, Water,
Earth, and Fire.   Their opinion has  been  well received
for many ages ; and it must be confessed that  it is  calcu-
lated to seduce the mind.   There  are, in fact,  enormous
masses, and inexhaustible stores, that present  themselves
to our view, of these four principles, to which the de-
struction or decomposition of bodies appeared to refer all
the several component parts  which formation or creation
had taken from them.  The authority of all those great
men who had adopted this system, and the analysis of bo-
dies which presented only these four principles, aftbrded
sufficient grounds for admitting this doctrine.
   But as soon as  chemistry had advanced so far as  to dis-
cover the principles of bodies, the professors of that sci-
ence presumed to mark the number, nature, and charac-
ter of the  elements ;  and every substance that was unal-
terable by the  chemical methods  of decomposition, was
considered by them as a simple or elementary principle.
By thus taking the limits of analysis as the term for indi-
cating the elements, the number and the nature of these
must vary according to the revolutions and  the progress
of chemistry.   This has accordingly happened, as may
be seen by consulting all the authors who have written on
this subject, from the time of Paracelsus to  the present
day.  But it must be confessed that it is no small degree
of rashness, to assume the extent of the power of  the ar-
tist as a limit for  that of the Creator, and to imagine that
the state  of our  acquisitions is  a state of perfect  know-
ledge. 
FIRE,  OR HEAT.
65
  The denomination  of Elements ought therefore to be
effaced from a chemical nomenclature, or at least it ought
not to be used but as an expression denoting the last term
of our analytical results; and it is  always in this sense
that we shall use the word.
                     CHAPTER I.


                   Concerning Eire.


     THE principal agent employed by nature to balance
      the power and natural  effect  of attraction, is  fire.
By the natural effect of attraction we should possess none
but  solid and compact bodies; but the caloric unequally
dispersed in bodies tends incessantiy to destroy this adhe-
sion of the particles;  and it is to this principle  that we
are indebted for the varieties of consistence  under which
bodies present themselves to our  observation.   The  va-
rious substances that compose this universe  are  therefore
subjected, on the one hand, to a general law which tends
to bring them together;  and, on the other hand, to a pow-
erful agent which tends to remove them from each other-:
it is upon the respective energy of these two forces  that
the consistence of all  bodies depends.  When the affinity
prevails,  they are in the solid state;  when the  caloric is
most powerful, they are in the state of gas; and the  li-
quid state  appears to be the point of the equilibrium be-
tween these two powers.
   It is therefore essentially necessary to treat of fire, since
it acts so leading a part in this universe;  and  because it
is  impossible to treat of any substance whatever, without
attending to the influence of this agent.
   There are two things to be considered in fire—heat and
light.
   These two principles, which have been very  often con-
founded, appear to be  very distinct  in their  own nature; 
66             FIRE.  HEAT.   LIGHT.

because they are scarcely ever proportional to each other,
and because each can exist without the other.*
   The  most usual acceptation of the word Fire compre-
hends heat and light; and its principal phenomena must
have been known for a long time.  The discovery of fire
must have been nearly as  ancient as the human species up-
on this  globe.   The shock of two flints, the action of me-
teors, or the effect of volcanos, must have aftbrded the ear-
liest idea of it;  and it is very astonishing that the inhabi-
tants of the Marian  islands were not acquainted with its
effects before the invasion of the Spaniards. These island-
ers, who became acquainted with  this terrible  element
only in  consequence of its ravages, considered it at first
as a malevolent being which attached itself to all be-
ings, and devoured them.—See the Abbe Raynal's His-
toire Philosophique, &e.
   The  effects of fire are  perhaps the most astonishing of
any which nature exhibits; and we ought not to be sur-
prised that the ancients considered it as an intermediate
being between spirit and matter, and have built the beau-
tiful fable of Prometheus  upon its origin.   We have had
the happiness, in our time, to acquire  well  founded and
extensive ideas respecting this agent, which we shall pro-
ceed to develop in the two following articles.

                      ARTICLE I.

             Concerning  Caloric and Heat.

   When a metal or a liquid is  heated, these bodies are di-
lated in every  direction, are reduced to vapour, and at last
become invisible when the most powerful heat is applied
to them.
   Bodies which possess the principle of heat, part with it
more or less  readily.  If we attentively observe a body
during its cooling, a slight movement of undulation will be
perceived in the surrounding air; an effect which may be

  * We see heat without light in iron heated very hot, and lightwith-
out heat in rotten wood, the solar phosphori, the fire-fly and glow-
worm, putrid fish, &c   The rays of the moon  collected into a focue
fey a concave mirror, give light without heat.—Am. Ed. 
GENERAL PROPERTIES OF HEAT.
67
compared to die phenomenon exhibited upon the mixture
of two liquors of unequal density and weight.
   It is difficult  t© conceive this phenomenon, without ad-
mitting of a peculiar fluid, which passes first from the bo-
dy which heats  to that which is heated, combines with the
latter, produces the effects we have spoken of,  and after-
wards escapes to unite with  other bodies, according to its
affinities, and the  law of equilibrium, to which all bodies
tend.
   This fluid  of heat, which we call Caloric,  is contained
in greater or less  quantities in bodies, according to the
greater or less degrees of affinity  existing between it and
them.
   Various  means may be employed  to displace or disen-
gage the caloric.   The first is by the method of affinities:
for example,  water poured upon the sulphuric acid expels
the heat, and takes its place;  and while  there is a disen-
gagement of heat, the volume of the mixture does not in-
crease in proportion to  the bulk of the two substances
mixed.  This  shews that penetration takes place, which
cannot be explained but by  admitting that  the integrant
parts of the water take the place of the caloric, in  propor-
tion as it is dissipated.—The second method of  precipi-
tating  caloric, is by friction and compression.   Jn this case
it is expressed or squeezed out, in the same  manner as
water from a sponge.   In reality, the whole of the  heat
which may be produced by friction, is not afforded by the
body itself; because, in proportion as the interior heat is
developed,  the external air acts upon the body, calcines or
inflames it, and itself gives out heat during its  fixation.
Fermentation, and in general every operation which changes
the nature  of bodies, may disengage caloric, because the
new compound may demand and receive  a greater or less
quantity.   Hence  it is  that chemical operations produce
sometimes  cold, and sometimes heat.
   Let us now examine the form under which caloric pre-
sents itself.
   This fluid  is  disengaged either in a state of  liberty, or
in a state of combination.
   In the first case, the caloric always endeavours to ob-
tain an equilibrium; not that it is distributed equally among
.all bodies,  but it is dispersed among them according to the 
$S           ADMEASUREMENT OF HEAT.
degrees of  its affinity.-  Whence  it follows, that the cir-
cumambient bodies receive and retain a  quantity more or
less considerable.  Metals  are  easily penetrated by this
fluid, and transmit it with equal facility; wood  and ani-
mal substances receive it  to the degree of combustion; li-
quids, until they are  reduced to vapour.  Ice absorbs all
the heat communicated to it, without giving it out to other
bodies until it has acquired the fluid state.
   The degree of heat can be appreciated only by its ef-
fects: and the instruments which have  been successively
invented to calculate it, and  are  known by the names of
thermometers, pyrometers, &c.  have been  applied to the
strict determination of the  several phenomena exhibited
in consequence  of the absorption  of caloric in various
bodies.
   The dilatation of fluids, or of metals  in the fluid  state,
by the several degrees of heat, has been long measured by
thermometers formed of  glass; but this very fusible sub-
stance can only  be used to ascertain degrees of heat inferi-
or to that which renders the glass itself fluid.
   Several means have been successively proposed for cal-
culating the higher degrees of heat.  Mr. Leidenfrost has
proved, that the hotter a  metal  is, the  more slowly will
drops of water evaporate  from its surface;  and he has pro-
posed this principle  for the construction of  pyrometers.
A drop of water in an iron spoon, heated to the degree of
boiling water, evaporates in one second; a similar  drop,
poured on melted lead, is dissipated in six  or  seven se-
conds;  and upon red-hot iron in thirty.  Mr. Ziegler, in
his Specimen de digestore  Papini,  has  found that 89 se-
conds were required to evaporate a drop of water at 520
degrees of Fahrenheit; and that one second is sufficient at
the 300th degree.   This phenomenon,  which is more in-
teresting to chemistry than pyrometry, to which it will al-
ways afford results little  susceptible of rigorous calcula-
tion, appears to me to depend upon the adhesion and de-
composition of the water upon the metal.
   The most accurate pyrometer we are acquainted with,
is that which was  presented to the Royal Society of Lon-
don by Mr. Wedgwood.   It is constructed upon the prin-
ciple, that the purest clay shrinks in the fire in proportion
to the heat applied to it.  This pyrometer consists of two 
WEDGWOOD'S THERMOMETER.          69
parts;  one called the gauge, which serves to measure the
degrees of diminution or shrinking; the other contains the
simple pieces of pure clay, which are called thermometer
pieces.
   The gauge is  formed of a plate of  baked earth, upon
which are applied two rulers or straight pieces of the same
substance.*  These  rulers,  being perfectly straight and
even, are placed at the distance of half an inch from each
other at one of their ends,  and three-tenths of an inch at
the other.  For greater convenience, the gauge is divided
into two parts,  and the two  pieces  are placed endways
when required to be used.   The length of this rule is di-
vided into 240 equal parts, of which each represents one-
tenth of  an inch.  To form the  thermometer pieces, the
earth is sifted with the greatest attention, after which it is
mixed with water,  and the paste thrust through an iron
tube, which gives it  a cylindrical form, to be cut after-
wards into pieces of a proper size.f  When the pieces are
dry, they must be presented to the gauge, where they
ought to fit at the place of 0 on the scale.   If by inadver-
tence of the workmen any piece penetrates to one or two
degrees further,  this degree is marked on its flat surface,
and requires to be deducted when the piece is used in  the
admeasurement of heat.   The pieces thus adjusted are
baked in a furnace to a red heat, to give them the con-
sistence  necessary  for carriage.   The heat employed in
this part of the process is usually about six degrees, and
the pieces are diminished more or less;  but this is of no
consequence when they come to  be submitted to a supe-
rior degree of  heat;  and if it should happen that an infe-
rior degree of  heat  is required to be measured, unbaked
pieces are to be  used, which are preserved in sheaths or
cases to avoid friction.
   When this pyrometer is to be used,  one of the pieces is
exposed in the fire-place whose  heat is required to be de-
termined;  and when it has acquired the whole intensity, it

   * Or of two brass rulers screwed down upon a flat piece of the same
metal.
   t The earth is passed through finer and finer sieves, the last of
which is a silk lawn, the interstices of whose  threads are less than
 150,000 parts of a square inch.—Am.. Ed. 
70              THt CALORIMETER OF
is taken out, or suffered to cool,  or for greater speed it is
plunged in water; after which it is presented to the gauge,
and its degree  of contraction easily  determined.    Mr.
Wedgwood has given us the result of several experiments
made with his pyrometer, opposite to which he has placed
the correspondent degrees of Fahrenheit.

                                      Pyrometer
                                     Of Wedgwood
Red heat visible by the light    -       -      0
Brass melts at      -      -     -        21
Swedish copper melts at       -       -     27
Pure silver melts at        -              28
Pure gold melts at      -      -       -     32
The heat of bars of iron raised to C small bar  90
  welding                    £ large bar  95
The greatest heat producible in a smith's forge 125
Cast iron melts at       -      -       -    130
The greatest heat of a wind furnace of eight } ..
  inches square                       y

  These various thermometers are not applicable to. all
cases.   We cannot, for example, calculate with strictness
the heat which escapes from living bodies,  or determine
with precision the temperature  of any substance.   But
Messrs. De la Place  and Lavoisier (Acad, des Sciences,
1780)  have  invented an apparatus which appears to leave
nothing further to be desired.   It is constructed upon the
principle that ice absorbs all the heat communicated to it,
without communicating it to  other bodies until the whole
isTnelted;   so that from hence  we may calculate the de-
grees of heat communicated, by the quantity of ice which
is melted.   It was necessary, in order to afford strict re-
sults, to discover the means of causing the ice to absorb
all the heat  disengaged from the  bodies  under examina-
tion, and to cover it  from  the action of every other sub-
stance which might facilitate its fusion; and, lastly to col-
lect with great care the water produced by the fusion.
  The apparatus constructed by these two celebrated aca-
demicians for this purpose, consists of three circular ves-
sels nearly inscribed in each other; so that three capaci-
ties are produced.  The interior space or capacity is formed
by an  iron  grating,  upon  supports of the  same  metal.
Here it is that  the bodies subjected  to  experiment are
Thermometer
Of Fahrenheit.
   1077
   1857
   4J587
   4717
   5237
  12777
  13427
  17327
  17977

  21877 
LAVOISIER AND DE LA PLACE.
71
placed.   The upper part of this cavity is closed by means
of a cover.   The middle space, next to this, is designed
to contain the ice which surrounds the interior compart-
ment.  This ice is supported and retained by a grate, up-
on which a cloth is spread.  In proportion as the ice melts,
the water flows through the grate and the cloth, and is col-
lected in a vessel  placed beneath.  Lastly, the external
space or compartment of the apparatus contains ice intend-
ed to prevent the effect of the external heat of the atmos-
phere.
   To use this excellent machine, the middle or second
space is filled with pounded ice,  as is  likewise the cover
of the internal sphere;  the same thing is done with regard
to the external space, as well as to the general covering of
the whole machine : die interior ice  is suffered to  drain;
and, when it ceases to  afford water, the covering of the
internal space  is raised, to introduce the body upon which
the experiment is intended to be made.   Immediately af-
ter this  introduction, the covering is  put on,  and the
whole apparatus remains untouched until die included bo-
dy lias acquired the temperature of 0, or the freezing tem-
perature of water;  which is the cpmmon temperature of
the internal capacity.   The quantity of water afforded by
the melting of the ice is then weighed; and tiiis is an ac-
curate measure of the heat disengaged from the body, be-
cause the fusion of the  ice is the effect of this heat only.
Experiments of this kind last fifteen, eighteen, or twenty
hours.
   It is of great consequence, that in this machine there
should be no communication between the middle, or se-
cond, and the  external  space.
   It is likewise necessary that the  air of the apartment
should not  be  lower than 0, because the interior ice would
then receive a degree of cold lower than that temperature.
   Specific  heat is  merely the proportional quantity  of
heat  necessary to  raise ^bodies  of equal  mass to the
same number  of degrees of temperature; so  that, when
the specific heat of  a  solid body is required, its tempera-
ture  must be elevated  a certain number of degrees,  at
which instant it must be placed in the internal sphere, and
there left until  its temperature is reduced to 0.  The water
is then collected, and this quantity divided by the product* 
 72         GENERAL PROPERTIES OF HEAT.

of the mass of the body; and the number of degrees of its
original temperature above 0, will be proportional to its
specific heat.
  With regard to fluids, they are inclosed in vessels whose
heat has been previously  determined.  The operation is
then the same as for solids;  excepting that the quantity of
water afforded must be diminished by a deduction of that
quantity which has been melted by the heat of the vessel.
  If it be required to determine the heat which is disen-
gaged during the combination of various substances, they
must be all reduced, as well as their containing vessels, to
the  temperature of 0.   The mixture must then be placed
in the internal sphere;  and the quantity of water collected
is the measure of the disengaged heat.
  In order to determine the heat of combustion and respi-
ration, as the renewal of air  is indispensable in these two
operations, it is necessary to establish a communication be-
tween the internal part of the sphere and the surrounding
atmosphere; and in order that the introduction of fresh air *
may not cause any perceptible error, these experiments
ought  to be made at a temperature littie differing from 0,
or at least the air which is introduced must previously be
brought to this temperature.
  To determine the specific heat of any  gas, it is neces-
sary to establish a current through the internal part of the
sphere, and to place two thermometers, one at the place of
introduction, and the other at the  place  of escape.   By
comparison of the temperatures exhibited  by these two in-
struments,  a judgment is formed of the heat absorbed, and
the  melted ice is measured.
  An excellent memoir of Messrs. De la Place and Lavoi-
sier may be consulted for the results  of the experiments
they have  made.   The present extract  contains only a
short account of their valuable labours.
  The various means made use of for the admeasurement
of heat, are founded on the general principle, that different
bodies absorb heat in greater or less  quantities.  If this
fact were not generally admitted, it  might be established
on the three following facts.  Dr. Franklin having expo-
sed two small pieces of cloth, of the same texture but of
different colours, upon the surface  of snow, perceived,
a few hours afterwards, that  the  red  cloth was  buried in 
           GENERAL PROPERTIES OF HEAT.         73

the snow, while the other which was was white had not
suffered any depression*.  M. de Saussure observes, that
the peasants of the mountains of Switzerland, are careful to
spread a black earth over the  surface of grounds covered
with snow, when they are desirous of melting it, to sow
their seed.   So  likewise children burn  a black hat in
the focus of a small lens which  would  scarcely heat a
white one.
   Such nearly are the phenomena of heat when it is dis-
engaged in  a state of liberty.   Let us now contemplate
those which it presents when it  escapes from a  state of
combination.
   Heat is sometimes disengaged in a state of simple mix-
ture, as in the phenomena of vapours,  sublimations, &c.
If heat be applied to water,  these  two fluids  will unite,
and the mixture will be dissipated in the atmosphere;  but
it would be an abuse of  words to call so weak an union
by the name of combination;  for,  as soon as the heat be-
comes in a situation to combine with other bodies, it aban-
dons the water, which returns to a liquid state.   This bo-
dy, during evaporation, continually carries with it a por-
tion of heat; and hence,  perhaps, result the advantages of
transpiration, perspiration, &c.
   But heat very frequently contracts a true chemical union
with the bodies which it volatilizes:  this combination is
even so perfect, that the heat is not perceptible, but is neu-
tralized by the body with which it is combined.   It is then
called latent heat, calor latens.
   The several cases in which heat enters  into combina-
tion, and passes to the state of latent heat,  may be reduced
to the two following principles:
   The first principle.—Every body which passes from the
solid to the liquid state, absorbs a portion  of heat, which
is no longer sensible to the thermometer,  but exists in  a
true state of combination.
   The academicians of Florence filled a vessel with pound-
ed ice, and plunged a thermometer in it, which descended
to 0.  The vessel was then  immersed in boiling water,
and the thermometer did not rise during the whole time of

        * They were exposed to the rays of the sun.  T.
                            K 
74         GENERAL PROPERTIES OF HEAT,

the liquefaction of the  ice.  The  fusion of ice therefore
absorbs heat.
  Mr. Wilcke poured a pound  of water,  heated to the
60th degree  of Reaumur, upon a pound of ice.   The
melted mixture possessed the temperature of 0.  Sixty de-
grees of heat had therefore entered into combination.
  The Chevalier Laudriani has shewn that the  fusion of
metals,  of sulphur, of phosphorus, of alum, of nitre, &c.
absorb heat.
  Cold is produced in the dissolution of  all the  (crystal-
lized) salts.
  Reaumur made a series of very interesting experiments
on this subject, which confirm those of Boyle. Fahrenheit
caused  the  thermometer to descend to forty degrees, by
melting ice by strong nitrous acid.  But  the  most  asto-
nishing experiments are those made by  Mr.  Walker, an
apothecary at Oxford,  and inserted in the  Philosophical
Transactions for  the  year 1787*.   The mixtures which
produced the greatest degrees of cold are, 1.  Eleven parts
of muriate of ammoniac, or  common sal ammoniac; ten
parts of nitrate of potash, or common nitre;  sixteen parts
of sulphate of  soda, or  Glauber's salt;   with  thirty-two
parts by weight of water:  the two first salts should be dry
and in powder.  2. The nitric acid, muriate of ammoniac,
and sulphate of soda,  lowered  the thermometer to  eight
degrees under 0.  Mr. Walker  has frozen mercury with-
out using either ice or snow.f
   It is therefore an incontrovertible principle,  that all bo-
dies which pass from the solid to the liquid state, absorb
heat, and retain it in so.accurate a combination as to af-
ford no sign  of its presence.  The heat is therefore fixed,
neutralized, or latent.
  The  second principle.—All  bodies,  by  passing  from
the solid or  fluid state to the aeriform state, absorb heat,
which becomes latent; and it is by virtue of this heat that
such bodies are placed and maintained in that state.
  On this principle is founded the process used in China,
India, Persia, and Egypt, to cool liquors used for drink.

  * Also in the subsequent volumes.
  t Many experiments have been made by the chemists, in order to
produce artificial cold.  The following table will shew how low the 
            GENERAL PROPERTIES  OF HEAT.          75

  The water  intended for  this purpose   is  put  into
very  porous  vessels,  and  exposed  to  the  sun,  or  to a
mercury in Fahrenheit's thermometer, may be reduced by a mixture
of the acids, water, and neutral salts;
Muriate of ammoniac 5 parts Nitrate of potash 5 Water 16	From 50° to 10°.
Muriate of ammoniac 5 parts Nitrate of potash 5 Sulphate of soda 8 Water 16	From 50° to 4°.
Sulphate of soda 3 parts Nitric acid diluted 2	From 50° to 3°.
Sulphate of soda 8 parts *Muriatic acid 5	From 50° to 0*.
Snow 1 part Muriate of soda 1	From 32° to 0*.
Snow or pounded ice 2 parts Muriate of soda 1	From 0° to —5°.
Pounded ice or snow 1 part Muriate of soda 5 Muriate of ammoniac 5 Nitrate of potash 5	From —5° to —18°.
Snow or pounded ice 12 parts Muriate of soda 5 Nitrate of ammonia 5	From—18° to—25°.
Snow and diluted nitric acid	From 0° to —46°.
Muriate of lime 3 parts Snow 2 By means of thh mixture a degree of cold has been produced equal to 90 deg. below 0.	From— 32° to— 50°.
Snow 1 part Diluted sulphuric acid 1	From —20° to —60°.
  The best and cheapest mixture to produce artificial cold, for cool-
ing liquors, is the sulphuric acid diluted with an equal bulk of water,
and suffered  to cool, and Glauber's salt in fine powder, retaining its
water of crystallization.  Five parts of Glauber's salt, and four of the
diluted sulphuric acid, will sink the mercury in a thermometer from
50° to 39.—Am. Ed. 
76
GENERAL PROPERTIES OF HEAt.
 current of warm  air,  to  cool  the  fluid contained within
 them.*
   It is by similar means that cool drink is obtained in the
 long journeys of the caravans.   Interesting details on this
 subject may be seen in the  Travels of  Chardin,  vol. iii.
 1723; Tavernier's Voyages, vol. i. edit. 1738; Paul Lu-
 cas's Voyages, vol. ii. edit. 1724;  and also in the Mun-
 dus Subterraneus of P. Kircher, lib. vi. sec. 2. cap. 2.
   We mav conclude from the experiments of Mr. Rich-
 mann, made in 1747, and inserted  in the first  volume  of
 the imperial  Academy of Petersburg,  1. That a thermo-
 meter taken  out of water, and exposed to the air, always
 descends, even when its temperature  is equal or superior
 to that of ihe water.  2.  That it afterward rises, until that
 it has  acquired the temperature of the atmosphere.   3.
 That the time  of descending is less than that which it em-
 ploys to rise again.  4.  That when the thermometer, with-
 drawn from the water, has arisen to the common tempe-
 rature, its bulb is dry;  but that it continues wet during
 the whole time of its standing beneath diis common tem-
 perature.
   To these consequences we will add others deduced from
 several curious experiments by the celebrated Cullen.   1.
 A thermometer suspended in the receiver of the air pump,
 descends two or three  degrees during the time of exhaus-
 tion, and afterwards rises  to the temperature of the vacu-
 um.   2. A thermometer  plunged  in alcohol, in the re-
 ceiver of the air pump, always  descends, and the lower in
 proportion as  the  bubbles are stronger which issue from
 the alcohol;  if it be withdrawn from this liquor, and sus-
 pended wet  beneath the  receiver,  it falls eight or ten de-
 grees while the air is pumping out.
  It is well known that if the ball of a  thermometer  be
 wrapped in fine linen, and kept moist by sprinkling with
 ether, and the evaporation be facilitated by agitation in the
 air, the thermometer will  descend to O.f

  * Water cannot be cooled in the United States, by permitting it to
transude and evaporate from the surface  of porous vessels.  They
merely  prevent it from becoming very hot.  Whether the vessels
are placed in the sun or the shade, the temperature of the water will
rise in the months of July or August, from 52" to 80° in the space of
a few hours.—Am. Ed-
  t The best mode of performing this experiment, is to sprinkle the
linen, with which the bulb of the thermometer is covered, with a mix-
 ure of equal parts of the sulphuric and muriatic ethers.—Am. Ed. 
GENERAL PROPERTIES  OF HEAT.
77
   The immortal Franklin has proved, in his own person,
that when the body  perspires strongly,  it  is  less heated
than surrounding bodies, and that perspiration always pro-
duces a certain degree of coldness.   See his letter to Dr.
Lind.
  The great number of  labourers in the burning heats of
our climate  support themselves only by virtue of a copious
perspiration, the fluid for which they  replenish by drink-
ing plentifully.   The workmen employed in glass-houses,
founderies, &c. often live in  a medium hotter than their
bodies, the natural temperature of which is equalized and
moderated by perspiration.
   If evaporation be  increased by agitation  of the air,  the
refrigeration is the greater.  Hence the use of fans, venti-
lators, &c. which, though intended to give motion to warm
air, afford likewise the virtue of cooling by facilitating and
favouring evaporation.
   Warm and dry air is  best suited to  form a refreshing
current, because it is more calculated to dissolve and  ab-
sorb humidity; moist air is less proper,  because it  is al-
ready saturated.—Hence the necessity of frequently  re-
newing the  air to preserve the coolness of our apartments.
   These principles have a nearer relation to medicine than
is generally  supposed.   We find that almost all fevers end
in perspirations, which,  beside the advantage  of expelling
the morbific matter, possess likewise that of carrying  oft
the matter of heat, and restoring the body to its common
temperature.   The physician who is  desirous of mode-
rating the  excess of heat in the body of a patient, ought to
maintain the air in that disposition which is most suitable
to his views.
   The use of volatile alkali is universally  acknowledged
to be of advantage in burns, the tooth-ach,  &c.  May  not
these effects be attributed to the volatility of this substance,
which quickly combining with heat,  carries it  off, and
leaves an impression of cold?—Ether is a sovereign  re-
medy for  the colic.  Does not its virtue depend on  the
same principles?
   The heat  which has entered into combination with bo-
dies during  their  transition from the solid to the liquid
state, or from this last to the aeriform state, may be again
exhibited by causing these substances to return again to 
78
PROPERTIES OF LIGHT.
the states of liquefaction or solidity.   In  a word, every
substance which passes from the liquid to  the solid state,
suffers its latent heat to  escape,  which at  this instant be-
comes free or thermometrical heat.
   The  celebrated Fahrenheit,  in the year  1724, hav-
ing deft water  exposed to  a  colder temperature  than
that of ice, the water remained fluid:  but it congealed by
agitation;  and the thermometer, which marked several
degrees beneath  the freezing point,  suddenly rose to that
temperature.   Mr.  Treiwald mentions a  similar fact in
the Transactions; and Mr. de Ratte made  the  same ob-
servation at Montpellier.
   Mr. Baume has shewn in his inquiries and experiments
relating to several singular phenomena exhibited by water
at the instant of its congelation, that  several degrees  of
heat are always developed at that instant.
   Gaseous substances are maintained  in the aeriform state
merely by the heat which is combined with them; and
when to these substances, thus dissolved in Caloric, ano-
ther body is presented,  to  which they have a very strong
affinity, they abandon their heat to unite with this last sub-
stance;  and the caloric,  thus expelled  or disengaged,  ap-
pears under the form of free or thermometrical heat. This
disengagement of heat, by the concretion or fixation of
gaseous substances,  was  observed  by  the celebrated
Scheele, as may be seen in the valuable experiments which
form the basis of his Treatise on Air and Fire.   Since the
time of this great man, rigorous calculations have  been
made of the quantity of latent heat existing in each of these
gases:  we  are  indebted to Messrs. Black, Crawford,
Wilcke, De la Place, Lavoisier,  &c.  for  many excellent
researches on this subject.


                     ARTICLE II.

                  Concerning Light.

   It appears that Light  is transmitted to our eyes by a pe-
culiar fluid which occupies the interval between us and vi-
sible bodies. 
        PROPERTIES AND EFFECTS OF LIGHT.      79

  Does this fluid arrive directly from the Sun by succes-
sive emissions or eradiations ?   or is it a peculiar fluid dis-
tributed through space, and put in action by the Sun's ro-
tary motion, or by any other cause ?  I shall not enter in-
to any discussion upon this subject, but shall confine my-
self to point out the phenomena.
  A.  The motion of light is so rapid, that it passes through
nearly eighty thousand leagues in a second.
  B.  The elasticity of the rays of light is such that the
angle of reflection is equal to the angle  of incidence.
  C.  The fluid of light is ponderous: for if a ray of light
be received through a hole in a window-shutter, and the
blade of a knife be presented to it, the ray is diverted from
a right line, and is inflected towards the body.   This  cir-
cumstance shews that it obeys the law  of attraction,  and
sufficiently authorizes us to class it among other bodies of
this nature.
   D. The great  Newton  succeeded in decomposing the
solar light into seven primitive rays,  which present them-
selves in the following order:  red, orange, yellow, green,
blue, indigo, violet.  Dyes present us  with only three co-
lours, which are red, blue, and yellow;  the combinations
and  proportions  of these three principles form  all the
shades of colour with which the arts are enriched.    Philo-
sophers have maintained that  among the solar rays there
are three primitive colours.—See Les  Recherches de M.
Marat.
   All natural bodies may be considered as prisms  which
decompose  or rather divide the light.   Some reflect the
rays without producing any change,  and these  are white;
others absorb  them all, and cause absolute  blackness: the
greater or less affinity of the several rays with various bo-
dies, and p'erhaps likew ise the  disposition of the pores,  is
no doubt the cause that, when a pencil  falls upon a body,
some rays enter into combination,  while others are reflect-
ed;  and it is  this which affords the  diversity  of colours,
and the prodigious variety of  shades under which bodies
appear to our eyes.
   We can no longer confine ourselves  to consider light as
 a merely  physical substance;  the chemist perceives its in-
 fluence in most of his operations, and finds it necessary to
 attend to its action, which modifies his  results: and its ef- 
 80      PROPERTIES AND EFFECTS OF LIGHT.

 fects are no less  evident in the various phenomena  of
 nature, than in the experiments performed in our labora-
 tories.
   We see that vegetation cannot take place without light.
 Plants deprived of this fluid  become pale;  and when  in
 hot-houses the light comes to them  from one part only,
 the vegetables incline towards the aperture,  as if to shew
 the necessity of this beneficial fluid.
   Without the influence of light, vegetables would exhi-
 bit but one  lifeless colour;  they  are deprived  of their
 beautiful shades by the interception of this luminous fluid.
 On these principles, celery, endive, and other plants, are
 bleached.
   Vegetables are not only indebted to the light for their
 colour, but  likewise for their smell, taste, combustibility,
 maturity, and the resinous principle, which equally depend
 upon this fluid.  Hence it is, no doubt, that aromatic sub-
 stances, resins,  and  volatile  oils,  are the inheritance  of
 southern climates,  where the light is more pure, constant,
 and intense.
   We  see,  likewise,  that the influence of light is evident
 in other beings: for, as Mr. Dorthes has observed, worms
 and grubs, which live in the earth  or in wood, are of a
 whitish colour.   The birds and flying insects of the night,
 are likewise  distinguishable from those of the day by the
 want of brilliancy of colour;  and the difference is equally
 marked between those of the north and of the south.
   A  very astonishing property of light upon the vegetable
 kingdom is,  that when vegetables  are  exposed  to open
 day-light, or to the sun's rays, they emit vital air.*  We
 shall  again attend to all  these phenomena when we come
 to treat of the analysis of vegetables.

  * This sentiment has been adopted by the chemists of all nations,
 but has lately been controverted by the editor of this work, who rea-
 sons in the following manner:
  1st. He says, whenever oxigenous gas has been obtained from ve-
 getables, carbonic acid, or fixed  air, has been present.  Upon re-
 viewing the experiments of Dr. Priestley, he finds that this circum-
 stance has actually taken place. The Doctor exposed plants to the
influence of light,in atmospheric air, in which spirit of wine, and wax,
and tallow candles, had burned out; to air which had  been vitiated by
the death or putrefaction  of mice and fishes ; and to air which had
been frequently taken into his lungs, and found that the purity of the 
PROPERTIES AND  EFFECTS OF LIGHT.       81
   The fine experiments of Scheele  and  Berthollet have
shewn that the absence or presence of fight has an asto*

air, was in every instance restored.  (Priestley on air.  Vol. iii. p.
247 to  349.)
  In all these cases, carbonic acid (which is composed of carbon and
oxigen) was formed; the vegetable  devoured its coal  for  food, by
which means its oxigen escaped in the form of pure air.
  2dly. The seeds of Zea maize or Indian corn, oiapium petroselinum
or parsley, of lactuca sativa or lettuce, of cucurbita citrullus or the wa-
ter melon, of phaseolua sativus or beans, and oiraphanus sativus or ra-
dishes, were planted in earth, and made to  vegetate in atmospheric
air, confined over water in vessels of white  glass, and exposed to the
action of solar light.  This air, when examined at various times, was
found to be reduced in purity ; and when its oxigenous portion was.,
completely absorbed, the plants died.   Its oxigen united to the coal
of the cotyledons of the seeds, or to that of  some animal or vegetable
matter contained in the earth in which they were planted, or to that
of some decayed  portion  of the leaves, and formed  carbonic acid
quicker than the living plant could decompose it.  To these experi-
ments we may add, that the celebrated  and accurate Scheele  ob-
served, that beans growing in atmospheric air  always rendered it
impure.
  Sdly. Young plants of datura stramonium or Jameston weed, of Phy-
tolacca decandra or the poke, of Zea maize or Indian corn, &c. grow-
ing in  earth, were exposed to solar lighl  in  from forty  to eighty
ounce  measures of atmospheric air, which was examined at various
times,  from  one hour to thirty  days after the plants had been placed
in it.   Carbonic acid gas  was generally formed,  and whenever this
circumstance happened, the purity of the air was diminished.
  When a plant in perfect health, growing in a soil which contains
little vegetable or  animal  matter, is confined in atmospheric air, it
will live a long time without producing any  change in it. Many of the
vegetables, which were the subjects of these experiments, did not af-
fect the air in five days ; some diminished its purity in three hours,
and others  altered it in  a most slow and  gradual manner,  causing
little change in it in 20 days.
  4thly. Many of the same kind of vegetables were also confined in
forty ounce measures of oxigenous gas, which had been well washed
in lime water, and the  purity of this air was very generally lessened,
carbonic acid being formed.
  5thly. A small handful  of the healthy leaves of a variety of plants,
containing no decayed parts, were exposed during four, six, and eight
hours to the influence of the light of the sun, in atmospheric air con-
fined by water, and its purity was found to be neither increased nor
diminished.
  6thly. The leaves of various vegetables  gathered promiscuously,
exposed in the same manner, generally diminished the purity of  at-
mospheric air several degrees.
  7thly.  A handful of the leaves of several hundred different plants,
among which may be mentioned those of the apple, pear, peach, pop- 
82      PROPERTIES AND EFFECTS OF  LIGHT.

nishing effect upon  the  result of  chemical experiments.
Light disengages vital air from several fluids, such as the

lar, fringe, and persimmon trees,  were  separately  exposed during
several hours in glass vessels to solar light, in forty  ounce measures
of pump water, and from five to nineteen  dram measures of oxigen
air were produced in  each vessel.   Upon analizint; the water, it was
found to contain-carbonic acid, with which it had been impregnated
from a necessary, which stood within a yard of the pump.
   8thly. The leaves  of thirteen different plants  were separately ex-
posed in the usual manner, in forty ounce measures of the water  of
the river Schuylkill,  and  about ten dram measures of air were pro-
cured, the principal part of which was azotic gas, which was disen-
gaged from the water.  No  carbonic  acid could be detected in the
water of this river.
   There are three wooden bridges erected over the Schuylkill, which
rest upon large wooden logs, upon which  great quantities of a species
of conferva grow, and which  is covered by the water. Upon viewing
this vegetable when the sun shone upon it, for several hours, at diffe-
rent times, for several years,  no air could be seen to form upon it, or
to rise through the water.
   9thly. The  leaves of the  same vegetables were exposed to light,
in the same manner,  in the same river water, impregnated with four
quarts of the water, saturated with carbonic acid, from the carbonate
of lime and the sulphuric acid ;  and seventy-seven dram measures
of oxigenous air of a very high degree of purity were obtained.
   lOthly.  No oxigenous air could be procured by exposing vegetable
leaves in boiled, distilled, rain or lime water; a proof that they  do
not decompose water.
   llthly.  Atmospheric air was impregnated with carbonic acid gas,
and an handful of the leaves  of nine different vegetables, were sepa-
rately exposed in it, to  light, seven hours. The fixed air disappeared,
and the atmospheric air was greatly increased in purity.
   12thly.  The limbs of trees covered with healthy leaves, and some
vigorous evergreens  growing in their natural soil, were confined from
one day to a month, in  atmospheric air over water,  and exposed to
light, and its purity.was never found to be  increased, but was generally
considerably diminished.
   These experiments incontestibly prove, that whenever oxigen gas
has been obtained from vegetables, by exposing them  to the influence
of solar light, carbonic  acid has been present, and that it is from the
decomposition of this gas, that the pure air is obtained.
   As it is acknowledged that the leaves of plants separate the oxigen
from  carbonic acid, it may be said, that the oxigenous portion  of at-
mospheric air is supplied by  the decomposition of this gas, as it is al-
ways found in the atmosphere.  The quantity of carbonic acid, acci-
dentally diffuseds iff  atmospheric air, (for it  is not one of its compo-
nant parts) is reckoned'to be about one part in an hundred. It must,
however, vary in different places.   We would expect to find the most
of it in cities, where it is formed by combustion,  respiration, fermen-
tation, and putrefaction.  If one measure of the  air of any great city 
PROPERTIES AND EFFECTS OF LIGHT.
83
nitric acid, the oxigenated marine acid, &c.   It reduces
the oxides or  calces of gold, silver, &c.   It changes the
nature of oxigenated muriates, according to the observa-
tions of Mr. Berthollet   Light  likewise determines  the
phenomena of vegetation exhibited by saline solutions, as
I have shewn. From all which circumstances it is evident
that we ought to attend  to the  effect of this  agent in al-
most all our operations.
   " Organization,  sensation,  spontaneous motion,   and
life, exist only at the surface of the earth, and in places
exposed to light: we might affirm that the flame of Pro-
metheus's torch was the  expression of  a philosophical
trudi which did not escape the ancients.   Without light,
nature  was lifeless,  inanimate,  and  dead: a  benevolent
God, by producing light, has spread organization, sensa-
tion, and thought  over  the surface of the earth."—Ele-
mentary Treatise of Chemistry by Mr. Lavoisier.
   We ought not to confound the solar light with the light
of our furnaces; the light of these has, as I am convinced,
very evident  effects in  certain phenomena:  but these ef-
fects are slow, and scarcely comparable with those of the
solar light.
   Although heat  often  accompanies light, the phenome-
na we have mentioned cannot be attributed to mere heat.
Heat may indeed modify them where it exists, but most
assuredly it cannot produce them.


be passed up over lime water, in an eudiometer, no carbonate of lime
will be formed,  so that the quantity of carbonic acid in this air, must
be  extremely small.   As this gas is also  seized upon by  alkalis,
earths and metals, and absorbed by water, the proportion of it in the
atmosphere may be less than one part in ten thousand.
   When we consider likewise, thatthe oxigen is never separated from
the carbonic acid by leaves,  but when they  are exposed in contact
with it to the light of  the sun, and that every perforation made in a
fiving leaf, however minute by an insect, causes the part to decay, and
absorb oxigen by day  and by  night; and that in the autumn, in some
countries, all leaves fall on the ground, ferment and putrefy, and thus
diminish the purity of common air; and that the petals and fruit of ve-
getables have  the same effect, we must pronounce that the oxige-
nous portion of atmospheric air cannot be supplied by vegetation.
                                                Am. Ed. 
84              ORIGIN  OF SULPHUR.
                    CHAPTER II.


                 Concerning Sulphur.

       WE are obliged to place  Sulphur  among the ele-
         ments,  though our  predecessors  pretended  to
have determined its constituent principles.  This proceed-
ing would appear to be  retrograde, if it were not evident
that die correction of mistakes is a real advancement in
science.
   The ancients  used the word  Sulphur  to denote every
combustible  and inflammable  substance.   Accordingly
we find, in all their writings,  the  expressions sulphur of
metals, sulphur of animals, sulphur of vegetables, &c.
   Stahl assigneth a determinate value  to the denomina-
tion of Sulphur; and since the time of this celebrated che-
mist we have confined the name to denote a body  of an
orange-yellow colour, dry, brittle, capable of burning with
a blue flame, and exhaling a penetrating  odour during
combustion:  when rubbed, it  becomes electric; and by
a light pressure in the  hand  it  cracks,  and becomes re-
duced to powder.
   It appears that sulphur is formed by the decomposition
of vegetables and animals.  It has been found on the wall»
of necessary-houses; and when the ditch of the  Porte St.
Antoine, at Paris,  was  cleared, a considerable quantity
was mixed with the decayed remains of vegetable and ani-
mal substances  that had  filled the ancient ditches, and
there putrefied.
   Mr. Deyeux has likewise proved, that sulphur  exists
naturally in certain plants, such as patientia, cochlearia,
he.  His processes for extracting it  consist in—1. The
washed root must be reduced by rasping into a fine pulp;
this must be washed in cold water, and passed through a
sieve or cloth of an open texture:  the fluid passes in a tur-
bid state, and deposites a precipitate, which when  dried
proves the existence of sulphur.   2. The pulp may be 
       PROCESSES FOR EXTRACTING SULPHUR.     85

boiled, and the scum afforded by the ebullition afterwards
dried:  this scum contains sulphur.  Several species of ru-
mex, confounded under the name of Patience, do not con-
tain sulphur.   I have obtained it from the rumex patien-
tia L, which grows on the mountains Cevennes, and is the
same which is used at Paris.   M. Le Veillard obtained
sulphur by suffering vegetable substances  to putrefy in
well-water.  Sulphur is abundandy contained in coal mines;
it is found in combination with certain metals;  it appears
almost always where vegetable decomposition takes place;
it forms the greater part of those pyritous and bituminous
schisti which occupy the focus of volcanos;  it is sublimed
in those places where the pyrites  are decomposed; it is
thrown out by subterraneous fires; and is found in  great-
er or less quantities in volcanic districts.   Much has been
said concerning showers of sulphur; but it is at present
well known that this error has chiefly arisen from the pow-
der of the  stamina of the pine, which is carried to great
distances.  Henckel saw the surface of a marsh entirely
covered with this powder*.
   The known processes for extracting sulphur in the large
way, and applying it to the purposes of commerce, consist
in disengaging it from the pyrites or sulphures of copper,
or of iron, by methods possessing various degrees of sim-
plicity and economy.  On this subject, the Pyritology of
Henckel, Macquer's Chemical Dictionary, and the Metal-
lurgical Tracts of Mr. Jars, may be consulted.
   Iii Saxony and Bohemia the ores of sulphur are distilled
in earthen tubes disposed in a gallery.  The sulphur which
is disengaged by the heat passes into receivers placed with-
out, and in which care is taken to  keep a sufficient  quan-
tity of water.

   * Sulphur is found at Farmington, Ontario county, state of New-
 York.  A stream large enough to turn a mill, rises from the bowels
of the earth, and emits sulphurated hydrogen  gas.   The hydrogen
 coming in contact with the oxigen of the atmospheric air, forms wa-
 ter, and "deposites the sulphur on the surface of the earth. The soil at
 this place rests upon a lime-stone rock, which in some places is sixty,
 and in others but a few feet deep.  The temperature of the water is
 50° of Fahrenheit's thermometer.
   Sulphur in fine powder is also met  with, adhering to the  sides of
 the large rocks, at the  Falls of Niagara,  and rises from sulphurated
 hydrogen gas.-—dm. Ed. 
86
ANALYSIS OF SULPHUR.
   At Rammelsburg, at St. Bel, &c. large heaps of pyrites
are made, which are decomposed by a gende heat,  at first
applied to the mass from a stratum of combustible  matter
upon which it is placed.   The heat is afterwards kept up
by the action of the pyrites amongst each other.  The sul-
phur which exhales cannot escape laterally, because care
is taken to cover the sides with earth. It therefore rises to
the summit of die truncated pyramid, where it is collected
in small cavities made for that purpose.   The heat  of this
part is sufficient to keep the sulphur in a fluid  state; and
it is taken out from time to time with ladles.
   Almost all the sulphur used in France comes from the
Solfatara.  This volcanic country every where  exhibits
marks of the agency of subterraneous fire.  The enormous
masses of pyrites which are decomposed in the bowels of
the earth produce heat, which sublimes part of the sulphur
through  apertures  which the fire,  and the effort  of the
vapours,  have opened  in all parts.  The earths and stones
which contain sulphur are distilled;  and it is the result of
this distillation which is called Cru(fe^Si#§feur.
   The crude sulphur is transported  into France by the
way of Marseilles, where it receives the necessary  prepa-
rations to render it suitable to various purposes.  I. It is
reduced  into sticks or rolls, by fusing it, and pouring it
into moulds: or, 2. It is formed into flowers of brimstone
by subliming it with a gentle  heat, and collecting this sul-
phureous vapour in a very close chamber of considerable
extent.   This very pure and finely divided sulphur is dis-
tinguished by-the name of Flowers of Brimstone, or Suh-
limed Sulphur.
   Sulphur enters into fusion by a moderate heat, and if the
moment  be seized in which the surface congeals, and the
liquid sulphur contained beneath that surface be then pour-
ed out, the internal cavity will exhibit long needle-formed
crystals of an octahedral figure.  This  process, contrived
by the famous Rouelle, has been applied to the crystalliza-
tion of almost all the metals.  Sulphur is found naturally
crystallized in Italy, at Conilla near Cadiz, &c.   Its usual
form  is octahedral;  but I have, nevertheless, seen crystals
of sulphur in perfect rhomboids.
   Stahl thought that he had proved, by analysis and syn-
thesis, that sulphur is formed by the combination of his 
ANALYSIS  OF SULPHUR.
87
phlogiston with the sulphuric acid.   The happy series of
proofs which he has left behind him for die establishment
of his opinion, has appeared so complete, that, since the
time of this great man, his doctrine has constantiy been
admitted as founded on absolute proof.   This example
was even urged as an instance to shew how high a degree
of evidence the chemical analysis was capable  of afford-
ing.  But our discoveries respecting gaseous  substances
have shewn us, that the ancients were necessarily led into
error for want of that knowledge. The immense researches
of the moderns into the composition of acids have shewn
that these substances are decomposed in a variety of ope-
rations; and  this revolution in the state of our knowledge
must  have produced a similar change in our methods of
explaining the phenomena.  An examination of the prin-
cipal experiments of Stahl, upon which his doctrine es-
sentially depends, will sufficientiy shew the truth of what
we have asserted.
   If one third part of charcoal, and two-thirds of sulphate
of pot-ash, or vitriotated tartar, be mixed and fused in a
crucible, the  product is (liver of sulphur) sulphure of pot-
ash.  If this  sulphur be dissolved in water, and the alkali
be engaged by adding a few  drops of sulphuric  acid, a
precipitate  is afforded,  which  consists of  true sulphur:
"whence," says Stahl, "the sulphur is a combination of
phlogiston, or the inflammable  principle  of the charcoal
with the sulphuric acid."   The experiment was true, but
the consequence is absurd; because  it would follow that
the sulphuric acid which was added,  must have possessed
the property of displacing sulphuric acid  united to the al-
kali.
  If Stahl had more strictly analized the result or product
of this operation, he would have been convinced that it
does not contain a particle of sulphuric acid.
  If he had been possessed of the power of operating in
closed vessels, and of collecting the  gaseous  substances
which are disengaged, he  would have obtained  a large
quantity of carbonic acid, which arises from the combina-
tion of the oxigene of the  sulphuric  acid with the char-
coal.
  If he had exposed his  liver  of sulphur to  the air  in
closed  vessels, he would have seen that the  vital air is ab- 
   88         PURE CHARCOAL, OR CARBONE.

   sorbed, tiiat the sulphure is decomposed, and that the sul-
   phate of  pot-ash,  or  vitriolated tartar is formed: which
   proves the re-composition of the sulphuric acid.
     If charcoal be moistened with sulphuric acid or oil of
   vitriol, and then exposed to distillation,  the products are
   carbonic  acid or fixed air, sulphur,  and  much sulphure-
   ous or volatile yitriolic acid.
     The experiments of Stahl exhibit the  most perfect de-
   monstration of the  decomposition of the sulphuric acid in-
.   to sulphur and oxigene;  and it is not necessary, in the ex-
   planation of them, either to suppose the existence  of an
   imaginary being, or to suppose that sulphur is a compound-
   ed body.
                    CHAPTER III.

          Concerning Carbone, or Diamond.*

    PURE charcoal is called Carbone in the new Nomen-
     clature.   This substance is placed among simple bo-
dies, because no experiment has hitherto shewn the pos-
sibility of decomposing it.
  Carbone exists ready formed in vegetables.   It may be
cleared of all the volatile and oily principles by distillation;
and, by subsequent washing in pure water, it may be de-
prived of all the salts which are mixed and confounded
with it.
  When it is required to procure  carbone in a  state of
great purity, it must be dried by strong ignition in a closed
vessel:  this precaution is necessary: for the last portions


  *  The diamond is nothing but charcoal in a crystallized state.  If
the focus of a large burning lens is thrown upon diamond powder,
confined in oxigen gas, the air disappears, and carbonic acid gas is
formed—Am. Ad. 
PURE CHARCOAL, OR CARBONE.
89
of water adhere with such  avidity,  that  they are decom-
posed, and afford oxide of carbone.*
   Carbone exists likewise in the animal kingdom; it may
be extracted by a process  similar to that which we have
described;  but its  quantity is small.    It appears in the
form of alight spungy mass, difficultly consumed m the air,
and mixed  widi a great quantity of phosphates, and even
of soda.                                         , . , .  .
   Carbone is  likewise found in plumbago, of which it is
one  of the princip'es f.
   We shall treat more fully of this substance in the ana-
lysis of vegetables.   But these concise ideas are sufficient
to enable us to proceed in our account of its combinations,
which is indeed the only object of the present short enu-
meration of its properties.


   * When charcoal is exposed  to a red heat, in an earthen retort, it
 yields carbonic acid gas, and oxide of carbone. Four ounces of it taken
 promiscuously from a heap, gave six hundred and twenty-two ounce
 measures of these airs.                  t
     The 1st   10 ounce measures was the  air  of the vessel.
         2d    4 contained 30 parts carbonic acid gas and 70 oxide
                   of carbone.
         3d    4 contained 20                        80
         4th   4         15                        85
5th 360         10
6th  70          2
7th 170          0
90
98
100
            622—Am. Ed.
  t Charcoal is unalterable and indestructible by age.  The beams
of the theatre at Herculaneum were converted into charcoal by  the
lava that overflowed that city ;  and during the lapse of seventeen
hundred years, the charcoal has remained as entire as if it had been
formed but yesterday, and it will probably continue so to the end of
the world.   The incorruptibility of charcoal was known in the most
ancient times ; the famous temple at Ephesus was built upon wooden
piles, which had been charred upon the outside to  preserve them.
Watson's Chemical Essays.—Am. Ed.
M 
90
CONVERSION  OF BODTEo
                     SECTION V.

Concerning Gases, or the Solution of certain Principles in Caloric,
           at the Temperature of the Atmosphere.


     CALORIC, in its combination with bodies, volatilizes
      some of  them, and reduces them to  the aeriform
state. The permanence in this state in the temperature of
the atmosphere constitutes the gases;  so that, to reduce a
substance to the state  of gas,  consists in dissolving it in
caloric.
   Caloric combines with various bodies, with greater or
less facility;  and we are acquainted with several that, at
the temperature of the. atmosphere,  are constantly in the
state of gas:  there are others which  pass to this state at
some degrees higher, and these are called Volatile or Eva-
porable substances.   They differ from fixed substances,
because these last are not volatilized  but by the applica-
tion and combination of a strong dose of caloric.
   It appears that  all bodies do  not indiscriminately re-
quire the same qiiantity of caloric to assume the gaseous
state;  and we shall see that this  proportion  may  be de-'
duced from the fixation and concretion of these gaseous
substances.
   To reduce any substance to the state of gas, the appli-
cation of calorie may be made in various manners.
   The more simple method consists in placing the  body
in contact with another body which is heated.   In this si-
tuation, the heat on one hand diminishes the affinity of ag-
gregation or composition, by separating the constituent
principles to a greater distance from  each other;  on the
other hand, the heat unites  to the principles with which  it
has the strongest affinity, and volatilizes them.  This pro-
cess is according to the method of simple affinities;  for it
 in fact consists of the exhibition of a  third body, which,
presented to a compound of several  principles, combines
 with one of them, and carries it off. 
BY HEAT INTO GASES,
91
   The method of double affinity may likewise be used to
convert any substance into the gaseous form; and this is
what happens when we cause one body to act upon ano-
ther to produce a combination, in wliich a disengagement
of some gaseous principles take place.   If I pour, for ex-
ample, the sulphuric acid upon the  oxide of manganese,
the acid combines with die metal,  while its caloric seizes
the oxigene, and rises with it.  This principle takes place
not only in this instance, but on all other occasions where-
in, an operation being performed without the application of
heat, there is a production of vapour or gas.
   The  various states under wliich bodies present them-
selves to our eyes, depend almost entirely upon the diffe-
rent degrees of combination of caloric with those same bo-
dies.   Fluids do not differ from solids, but because they
constantly possess, at the  temperature of the atmosphere,
the dose of caloric which  is requisite  to maintain them in
that state; they  congeal  and pass to the concrete  state
with greater or less facility,  accordingly as  the requisite
quantity of caloric is more or less considerable.
   All solid bodies are capable of passing to the gaseous
state; and the only difference which exists between them
in this respect is,  that a dose of caloric is required for this
purpose, which is governed—1.  By the affinity of aggre-
gation, which connects their principles, retains them, and
opposes  itself to a  new combination.  2.  By the weight
of the constituent parts, which renders their volatilization
more or less difficult.  3.  By the agreement and attrac-
tion between  die caloric  and die solid  hody,  which is
more or less strong.
   All bodies, whether solid or liquid, when they come to
be volatilized by heat, appear in  two states—that  of va-
pour, or that of gas.
   In the first case, these substances lose, in a. short time,
the caloric which raised them, and  again  appear in  their
original form the moment the caloric  finds colder bodies
to combine with; but it is rare that bodies thus divided
resume  their original consistence.   Tl^is first state is that
of vapour.
   In the second case, the combination of caloric with the
volatilized substance is such,  that the ordinary tempera- 
92
EXPERIMENTS ON GASES.
ture of the atmosphere is insufficient to overcome this uni-
on.  This state constitutes the gases.
   When the combination of caloric with any substance is
such that a gas is produced, these invisible substances may
be managed at pleasure, by the assistance of apparatus ap-
propriated within our time to these uses.   These appara-
tus are known by the name of Pneumato-chemic, Hydro-
pneumatic apparatus, &c.
   The pneumato-chemical apparatus, in general, consists
of a wooden vessel, usually of a  square form, and lined
with lead or tin:  two or three inches  beneath the upper
edge there  is formed a  groove, in which a wooden plank
slides, having a hole in the  middle, and a notch in one of
its sides; the hole is made in the  centre of an excavation
made in the shelf, of the figure of a funnel.*
   This vessel is filled with  water or mercury, according
to the nature of the gases operated upon.  There are some
which easily combine with water, and therefore require to
be received over mercury.
   The gases may be extracted in various manners.
   When  they are disengaged by fire, a recurved tube f
is adapted to the neck of the retort, one extremity of which
is plunged in the water or the mercury of the pneumato-
chemical vessel, and opens  beneath the aperture in  the
shelf, which is in the form of a funnel.   The junction of
the tube with the  neck of the  retort is secured with the
usual lute;  a vessel filled with the liquid of the cistern is
inverted upon the shelf over the aperture.   When the gas
is disengaged, from the materials in the retort, it appears
in the form of bubbles, which rise, and gain the superior
part of the inverted vessel.  When all the water is dis-
placed, and the  bottle is  full of gas,  it is withdrawn, by
adapting a glass platei to its orifice to prevent its dissipa-
tion: it may then be poured from one  vessel  to another,
and subjected to a variety of experiments to ascertain its
nature.

   * The best pneumato-chemical apparatus is made of a small cedar
tub, without any lining.  Vide plate ii. fig. 1.—Am. Ed.
   t There is no occasion for a recurved tube.  The neck of the re-
tort should enter under the shelf of the hydro-pneumatic tub.__Am.
Ed.
   i Queen's-ware saucers or soup-plates,  are preferable to -■lass.__
Am. Ed. 
HYDROGENOUS GAS, &C.
93
  When the gases are disengaged by means of acids, the
mixture which  is designed to afford them is put into a
bottle widi a recurved tube fitted to its neck; and this tube
is plunged in  the cistern in such a manner, that the bub-
bles of gas may pass, as in the former experiment, through
the aperture of the funnel in the shelf.
  The processes at present used to  extract the gases, and
to analize them, are simple and commodious:  and  these
processes have singularly contributed to our acquisition of
the knowledge  of these aeriform substances, whose disco-
very has produced a revolution in chemistry.
                     CHAPTER I.


   Concerning Hydrogenous Gas, or Inflammable Air.

   INFLAMMABLE Air is one of the constituent parts
    of water ; a circumstance which has entitled it to the
denomination of Hydrogenous Gas.   Its property of burn-
ing with vital air,  has caused it to be distinguished  by the
name of Inflammable Air.
   Hydrogenous  gas has been procured long since.   The
famous  philosophical candle attests the antiquity of this dis-
covery;  and the celebrated Hales obtained from most ve-
getables an air which took fire.
   Hydrogenous gas may be extracted from all bodies in
which it is a constituent part;  but the purest is that  af-
forded by the decomposition of water,  and it is this fluid
which usually affords it in our laboratories.   For this pur-
pose the sulphuric acid is poured upon iron,  or zinc; the
water, which serves as a vehicle for the acid, is decompos-
ed on  the  metal;  its  oxigene combines  with it, while
the hydrogenous gas escapes.   This explanation,  however
contrary to the ancient notion,  is not the less a demon-
strated truth; in fact, the metal exists in the state of an ox-
id^ in its solution by the sulphuric  acid, as may be proved
by precipitating it with pure vegetable alkali:  on die other 
94
HYDROGENOUS  GAS,
hand, the acid itself is not all decomposed; so that the ox-
igenous gas cannot have been afforded to the iron but by*
the  water.   Water  may be  decomposed likewise still
more directly  by throwing it upon iron strongly heat-
ed;  and  hydrogenous gas may  be obtained by causing
water to pass through a tube of iron ignited to whiteness.*
   The hydrogenous gas may be extracted by the  simple
distillation of vegetables.   Vegetable fermentation,  and
animal putrefaction, likewise produce this gaseous sub-
stance, f
   The properties of this gas are as follow:
   A. Hydrogenous gas has a disagreeable, stinking odour.
Mr. Kirwan has observed, that when it is extracted over
mercury,  it  has scarcely  any smelk   It contains half its
weight of water,  and loses its smell the moment it is  de-
prived of this additional substance.
   Kirwan has likewise observed, that the volume of  hy-
drogenous gas is one-eighth larger when received over wa-
ter than when received over mercury.
   These  observations appear to prove, that  the offensive
smell of this gas arises only from the  water it holds in so-
lution.
   B. Hydrogenous gas is not proper for respiration. The
abb6 Fontana assures us that he could not take more than
three inspirations of  this air: the  count Morozzo  has
proved that animals perish in it in a quarter of  a minute.
On the other hand, several northern chemists have affirm-
ed, in consequence of experiments made on themselves,

   * When the sulphuric acid diluted with water is poured upon zinc,
the oxigen of the water unites to the zinc and forms an oxide of zinc ;
this oxide is dissolved by the sulphuric acid, and sulphate of zinc or
white vitriol is formed;  the hydrogen of the water escapes in the
form of inflammable air.  One ounce of iron or zinc will yield three
hundred and sixty-five ounce measures of hydrogenous gas.
   The best mode of procuring inflammable air, is to fill an eight
ounce vial half full of small iron tacks, and cover them with water.
Then pour over them gradually about one ounce measure of the sul-
phuric acid, and adapt a bent glass, tin or copper tube, entering a per-
forated cork, to the mouth of the vial.  Vide plate  ii. fig. 5.—Am.
Ed.
   t This is a mistake. The gases obtained by vegetable fermentation
or distillation, are carbonic acid gas, carbonated  hydrogen gas, and
oxide of carbon.—Am. Ed. 
OR INFLAMMABLE  AIR.
95
tliat hydrogenous gas might be respired without danger;
and it is some years since the unfortunate Pilatre du Rozier
filled his lungs with it at Paris, and set it  on fire during
the expiration, which forms a very curious jet of flame.
It was remarked to him, that  the abb£ Fontana had  ob-
jected against the accuracy of the Swedish chemists. This
intrepid philosopher answered the objection by mixing one-
ninth of  atmospherical air  with very pure hydrogenous
gas.   He respired this mixture, as usual;  but when he
attempted to set it on fire, the consequence was an explo-
sion so dreadful, that he imagined all his teeth were blown
out.
   This opposition of opinions, and contradiction  of expe-
riments, respecting a  phenomenon which  seems capable
of unanswerable decision by  one single experiment,  in-
duced me to have recourse to trial, to fix my own ideas
on the subject.
   Birds,  successively placed in a vessel of  hydrogenous
gas,  died,  without  producing the  smallest perceptible
change in the gas itself.
   Frogs placed in forty inches of hydrogenous gas died
in the space of three hours and a half; while others lived
fifty-five hours in oxigenous gas and atmospheric air; and
when I took them out still living,  the air was neither vi-
tiated nor diminished.  Numerous  experiments  which I
have made  upon these animals,  have led me to observe
that they have the  faculty of stopping their respiration,
when placed in any noxious  gas, to such a  degree, that
 they inspire only once or twice, and  afterwards  suspend
every function on the part of the respiratory organ.
   I have since had occasion to observe that these animals
are not reduced into a putrid mass by remaining in hydro-
genous gas, as was affirmed  some  time ago.  The fact
which may have imposed on chemists who related this
 circumstance,  is,  that frogs  are often enveloped  in a mu-
 cus or sanies, which appears  to cover them; but they ex-
 hibit the same phenomenon in all the gases.
   After having tried the hydrogenous gas upon animals,
 T determined to respire it myself;  and I found that the
 same volume of this air  might be several times respired
 without danger.  But I observed  that this gas was not
 changed by these operations; whence I concluded that it 
96
HYDROGENOUS GAS,
is not respirable:  for, if it were, it would suffer a change
in the lungs, the object of respiration  not  being confined
to the reception and emission of a fluid merely;  it is a func-
tion much more noble,  more interesting, more intimately
connected with the animal  economy:  and we  ought to
consider the lungs as an organ which is  nourished by the
air, digests that which is presented to it, retains the bene*
ficial, and rejects the noxious part.  Since, therefore, in-
flammable  air can be  respired  several  successive times
without danger to the individual,  and  without any altera-
tion or change in  itself, we may conclude indeed that in-
flammable air is not a poison, but that it cannot be consi-
dered as an air essentially proper to respiration.  It is with
hydrogenous gas in the lungs, as with those balls of moss
and resin which certain animals swallow during the rigor-
ous season of the winter.   These balls  are not digested,
since the animals  void them at the return  of spring:  but
they delude hunger;  and the  membranes of the  stomach
are exercised upon them without danger, in the same man-
ner as the lungs exert themselves upon the hydrogenous
gas presented to them.
  C.  Hydrogenous gas is not combustible alone; it does
not burn but by the concurrence of oxigene.  If a vessel
filled with this gas be reversed, and a lighted taper be pre-
sented to it, the hydrogenous gas is found to burn at the
surface of the vessel;  but  the candle  is extinguished the
moment it is plunged lower.  The most inflammable bo-
dies, such as phosphorus, do not burn in  an  atmosphere
of hydrogenous gas.
  D. Hydrogenous gas is lighter than common air.  One
cubic foot  of atmospheric air weighs seven hundred and
twenty grains;  a  cubic foot of hydrogenous  gas weighs
seventy-two grains.   The barometer being at 29' 9, and
the diermometer 60° Fahrenheit,  Mr. Kirwan found the
weight of this air  to that of common air as eighty-four to
one thousand; consequently it was about  twelve times as
light.
  Its specific gravity varies very much, because it is diffi-
cult to obtain it constantly of the same degree of purity
That which is extracted from vegetables contains the car-
bonic acid and oil, which increases its weight. 
OR INFLAMMABLE AIR
97
   This levity of hydrogenous gas has caused certain phi-
losophers to presume that it ought to arrive at and occu-
py the superior part of our atmosphere;  and upon this sup-
position the most brilliant conjectures have been made res-
pecting the influence which a stratum of this gas, predo-
minating over the rest of the atmosphere, ought to produce
in meteorology.   They were not aware that this continual
loss of matter is not agreeable to the v\ise economy of na-
ture.   They did not observe that  this gas, during its as-
cent in the air, combines with other bodies,  more especi-
ally the oxigene, and that water and other products are the
result; the knowledge of which must necessarily lead us to
that of most meteors.
  The theory of balloons, or aerostatic machines,  is found-
ed on this levity of the hydrogenous gas.
  In order that a balloon may rise  in the atmosphere, it is
sufficient that the  weight of the balloon  itself,  and the air
it encloses, should be less considerable than that of an equal
bulk of atmospheric  air; and it  must rise till  its weight
is in equilibrio with an equal volume of  the sun-ounding
air.
  The  theory of the Mongolfiers is very different from
this.  In this case a given volume  of atmospheric; air  is
rarefied by  heat, and  kept separated  from the  common
mass by a hollow vessel of cloth.  This rarefied space may
therefore be considered for a moment as  consisting  of a
mass of air of greater levity, which must necessarily make
an effort to rise in the atmosphere,   and carry its  covering
along with it.
  E.  Hydrogenous gas exhibits various characters, ac-
cording "to its degree of purity, and the nature  of die sub-
stances  which are mixed with it.
  It seldom happens  that this gas is pure.  That which
is afforded by  vegetables contains  oil, and  the  carbonic
acid.   The  inflammable air of  marshes is mixed with a
greater or less quantity of carbonic acid; and  that which
is afforded  by the decomposition  of  pyrites  sometimes
holds sulphur in solution.
  The colour of  hydrogene, when set on fire, varies ac-
cording to its mixtures. One-third of the air of the lungs,
mixed with the inflammable air of pit-coal, affords a flame
of a blue colour;  inflammable air, mixed with  nitrous air,
                            N 
98
HEPATIC CAS.
affords a green colour; the vapour of ether affords a white
flame.   The various mixtures of these gases, and the de-
gree of compression  to which they  are subjected, when
expressed out of an aperture in order to burn them, have,
in the hands of certain operators, aftbrded very agreeable
illuminations, well deserving the attention of learned and
curious observers.
   F.  Hydrogenous gas possesses the property of dissolv-
ing sulphur.  In this  case it contracts a stinking  smell,
and forms hepatic gas.
   Mr. Gengembre  put sulphur into inverted vessels filled
with hydrogenous gas, and dissolved it by means of the
burning-glass.  The hydrogenous gas, by this treatment,
obtained all the characteristic properties of hepatic gas.
   The formation of this gas is almost always an effect of
the decomposition of water.  In fact,  the  alkaline  sul-
phures, or livers of sulphur, do not emit any disagreeable
smell while they are dry;  but the moment they are mois-
tened, an abominable smell is perceived,  and sulphate of
potash, or vitriolated tartar, begins to be  formed.   These
phenomena prove that the water is decomposed; that one
of its principles unites  to  the sulphur, and volatilizes it;
while the other combines with the alkali, and forms a more
fixed product.
   Sulphurated hydrogenous gas may be  obtained by dis-
solving the sulphures or hepars by acids.   Those acids in
which the oxigene  is  most adherent disengage the great-
est quantity.   The muriatic acid produces twice as much
as the sulphuric.   That which is produced by this last,
bums with a blue flame; but that which is disengaged by
the muriatic acid, burns with a yellowish white flame.
   Scheele has taught us the means of  obtaining this gas
in great  abundance, by decomposing artificial pyrites,
formed by three parts  of iron and one of sulphur, to
which spirit of vitriol is added.
   The natural decomposition of pyrites in the bowels of
the.earth produces this gas;  which  escapes with  certain
waters, and communicates peculiar virtues to them.
   The most general properties of these gases are:
   1.  They render the white metals black.
   2.  They are improper for respiration.
   3.  They impart a green colour to most blue vegetable
substances. 
VITAL AIR.
99
  4. They burn with a light blue flame, anddeposite sul-
phur by this combustion.
  5. They mix with the oxigenous gas of the atmosphe-
ric air, and form water;  at the same time that the sulphur,
before held in solution, falls down.  Hence it happens that
sulphur is found in the channels of hepatic waters, though
their analysis does not shew the existence of an atom qf
that substance held in solution.
  6. They impregnate water,  and are sparingly soluble
in that fluid;  but heat or agitation dissipates them again.
  The air which burns at  the surface of certain springs,
and forms what is known by the name of burning springs,
consists of hydrogenous gas holding phosphorus in solu-
tion.  It smells like  putrid fish.  The Pere Lampi has
discovered one of these springs in the isles of St. Colom-
bat.   Dauphiny exhibits another similar spring at the dis-
tance of four leagues from Grenoble.  The ignes fatui
which glide along burying-grounds, and which the super-
stitious people suppose to  consist of the spirits of the de-
parted, are phenomena of this nature, which we shall speak
of when we come to treat of phosphorus,.
                    CHAPTER II.

       Concerning Oxigenous Gas, or Vital Air.

     THIS gaseous substance was discovered by the cele-
      brated Priestley,  on the 1st of August, 1774.  Since
that memorable day, means have been devised of obtain-
ing it from various substances;  and its properties have
shewn that it is a production of the most interesting nature
in the knowledge of chemistry.
   No part of the atmosphere exhibits vital air in its great-
est degree of purity.   It is always combined, niixed,  or
altered by other substances. 
100
VITAL AIR.
   But this air, which is the most general agent in the ope-
 rations of nature, exists in combination with various sub-
 stances; and it is by their decomposition that  it may be
 extracted and procured.
   A metal  exposed to the air  becomes changed; and
 these changes are produced only by the combination  of
 the pure air with the metal  itself.  Simple distillation  of
 some of these metals thus changed, or oxides,  is sufficient
 to disengage this vital air;  and  it is then obtained in a
 very pure state, by receiving it  in the hydro-pneumatic
 apparatus.  One ounce of red precipitate affords about a
 pint.
   All acids have vital air for their base;  there are some
 which yield it easily. The distillation of nitre decomposes
 the nitric acid;  and about twelve hundred cubic inches of
 oxigenous gas are obtained from a pound of this salt.*
   The nitric acid, when distilled from various substances,
 is decomposed, and its constituent parts may be obtained
 separately.
   Messrs. Priestley, Ingenhousz, and Sennebier discover-
 ed nearly at the same time that vegetables exposed to the
 light of the sun emit vital air.  We shall elsewhere speak
 of the circumstances of these phenomena;  but shall  at
 present confine ourselves  to the observation, that the emis-
 sion of vital air is proportioned to the vigour of the plant,
 and  the vivacity of the light;  and that the direct emission
 of the rays of the sun is not necessary to  produce this ga-
 seous dew;  it is sufficient that the plant be well enlight-
 ened, in order that  it may transpire pure  air:   for I have
 often collected it in abundance from a kind of moss which
 covers the bottom of a vessel filled with water, and so well
 defended, that the sun never shone directly upon it.
   In order to procure the vital air which is  disengaged
 from plants, it is sufficient to enclose them beneath a glass
 vessel filled with water, and inverted over a tub filled with
 the same fluid.   The moment the plant is acted on by the
sun,  small bubbles of air  are formed on its leaves, which

  * The air obtained from nitre is so contaminated with azotic gas,
one of the component parts of  the nitric acid, that it hardly deserves
the name of pure air.—Am. Ed. 
VITAL AIR.
101
detaching diemselves, rise to die upper part of the vessel,
and displace the liquid.
   This dew of vital air is a beneficial gift  of nature,  to
repair incessantly the consumption of vital air.  The plant
absorbs atmospherical mephitis, and emits vital air. Man,
on the contrary, is kept alive by vital air, and emits much
mephitis.   It appears therefore that the animal and vege-
table kingdoms labour for each other;  and  that  by this
admirable reciprocity of service the atmosphere is conti-
nually repaired,  and an equilibrium maintained between
its constituent principles.
   The influence  of solar light is not confined to the pro-
duction of vital air by its action upon vegetables alone ;
it  has likewise the singular property of decomposing cer-
tain substances,  and disengaging this gas.*
   A bottle  of oxigenated muriatic acid,  exposed to the
sun, suffers all the superabundant oxigene which  it con-
tained to escape,  and passes to the state of  ordinary mu-
riatic, acid.  The same acid, exposed to the sun in a bot-
tle wrapped in black  paper, does not suffer any change ;
and,  when  heated in a dark place,  is even reducible into
gas without decomposition.   The nitric acid likewise af-
fords oxigenous gas,  when  exposed to the sun ; whereas
heat alone volatilizes it  without decomposition.
   The muriate,  or marine  salt of silver,  placed under
water, and  exposed to the sun, suffers oxigenous gas  to
escape from it.  I have observed that red precipitate like-
wise affords oxigene in  similar cases, and that it becomes
black in no very  long space of time.
   We may likewise obtain oxigenous gas by disengaging
it from its bases by means  of the  sulphuric acid.  The
process to which  I  give the  preference,  on account of its
simplicity,  is the following:—I take a small apothecary's
phial,  into which I put one or two ounces of manganese,
and pour thereon  a sufficient quantity of sulphuric acid  to
form a liquid paste.  I afterwards fit a cork to the opening
of die  bottle, with  a hole through it, into which is insert-
ed a recurved tube ;  one of whose extremities enters the
bottle,  while the  other  is placed under the  shelf of the

   * Vide what has been said in note p. 100.—Am. Ed. 
102
VITAL  AIR.
pneumato-chemical  apparatus.   When the  apparatus  is
thus disposed, I present a small coal to die lower part of
the bottle, and oxigenous gas is immediately disengaged.
   The manganese I use was discovered by me at St. Jean
de  Gardonnenque.  It affords its oxigene with such faci-
lity, that  nothing more is necessary for this purpose than
to incorporate it with the  sulphuric acid.  This gas  is not
perceptibly mixed with nitrogenous gas (or phlogisticated
air);  and the first bubble is as pure as the  last. *
   Oxigenous gas exhibits certain properties, according to
its  degree of purity.   These depend in general  upon the
substances which afford it.  That which is obtained from
the mercurial oxides almost always holds a small quantity
of mercury  in  solution:  I have  been a  witness  to  its
having  produced a speedy salivation on two persons who
used it for  disorders of  the  lungs.   In  consequence of
these observations, I filled bottles with this gas, exposed
them to an intense cold,  and the sides became  obscured
with a stratum of mercurial oxide, in a state of extreme
division.   I have several times heated the bath, over  which
I caused  this gas to pass;  and I obtained,  at two different
times, a yellow precipitate in the bottle in which I had re-
ceived  the gas.
   The oxigenous gas extracted from plants  is not equally
pure with that afforded by the metallic oxides :f  but from
whatever substances it is obtained, its  general  properties
are the following:
   A. It  is more ponderous than the air of the atmosphere;
 the cubic foot of atmospherical air  weighing seven hun-
 dred and twenty grains, while the cubic  foot of pure air
 weighs seven hundred and sixty-five.   According to Mr.
 Kirwan,  its weight is  to that of common  air  as  eleven

   * The best method of obtaining oxigenous gas, is by exposing
 the black  oxide of manganese to a red heat in an iron matrass.
 When procured  in this manner, it is generally contaminated with
 carbonic acid gas and azotic air.  The carbonic acid may be se-
 parated, by washing the  gases in lime water, but there is no mode
 of removing  the azotic air.—Am. Ed.
   t Twelve ounce measures of the oxigene air, obtained by exposing
  vegetable leaves  to the influence of solar light, in water  impreg-
  nated with carbonic acid gas, contained four ounce measures of
  azotic air.—Am.  Ed. 
VITAL AIR.
103
hundred and three to one  thousand.   One hundred and
sixteen inches of this air weighed 39,09 grains;  one hun-
dred and sixteen  inches of common  air weighed 35,38
grains at the temperature of ten degrees of Reaumur, and
twenty-eight inches  of pressure.  One hundred parts of
common air  weighed forty-six, and one hundred parts of
vital air fifty.
  B. Oxigenous gas is the only fluid proper for combus-
tion.   This  acknowledged  truth caused  the celebrated
Scheele to give it the name of  Air of Fire.
  To proceed with  greater  order in the examination of
one of the  most important  properties of oxigenous gas,
since it belongs exclusively to this fluid, we shall lay down
the  four following  principles,  as incontestable  results of
all the known facts.
  The first  principle.—Combustion never  takes  place
without vital  air.
  The second principle.—In every combustion  there is
an absorption of vital air.
  The third principle.—There is  an augmentation of
weight in the products of combustion equal to the weight
of the vital air absorbed.
  The fourth principle.—In all combustion there is a dis-
engagement of heat and light.
  I. The first of these propositions is a strict truth.  Hy-
drogenous gas does not burn alone, without the assistance
of oxigene ;  and all  combustion ceases the moment that
oxigenous gas is wanting.
  II.  The second principle contains a truth no less  gene-
ral.   If certain bodies, such as phosphorus, sulphur, he.
be burned in very pure oxigenous gas, this is absorbed to
the last particle ; and when the combustion is effected in
a mixture of several gases, the oxigene alone is absorbed,
and  the others remain unchanged.
  In the slower combustions, such as the rancidity of oils,
and the oxidation of metals, there is  equally an  absorp-
tion of oxigene, as may be shewn by confining these bo-
dies in a determinate mass of  air,
   III. The  third principle, though not less true than the
preceding, requires more explanation; and  for this pur-
pose we shall distinguish those combustions whose result,
residue, and product are  fixed,  from  those which  afford 
104                  VITAL  AIR.
volatile and fugacious  substances.  In the first case the
oxigenous gas quietly combines with the body; and by
weighing the same boay the moment the combustion has
completely taken  place, it is easily ascertained whether
the increase in weight be proportioned to the oxigene ab-
sorbed.  This happens in all the  cases wherein the metals
are oxided,  or oils rendered rancid; and  in  the  produc-
tion of certain acids, such as the phosphoric, the sulphu-
ric, &c.   In die second case, it is more difficult to weigh
all the results of the combustion,  and consequently to as-
certain whether  the augmentation in weight be propor-
tioned to the quantity of the air absorbed. Nevertheless,  if
the combustion be made in inverted vessels, and the whole
of the products be collected, it is found  that their  aug-
mentation in weight is  strictly equal to that of the air ab-
sorbed.
   IV. The fourth principle is that whose  applications are
the most interesting to be known.
   In most combustions, the oxigenous gas becomes fixed
and concrete.   It therefore abandons the caloric which
maintained it in the aeriform state;  and this caloric being
set at liberty, produces heat,  and endeavours to combine
itself  with the substances nearest  at hand.
   The disengagement  of heat is therefore a  constant ef-
fect in all the cases wherein  vital  air is fixed in  bodies;
and it  follows, from this principle—-1.  That heat is most
eminently resident in the oxigenous gas which maintains
combustion.  2.  That the more oxigene  is  absorbed in
a given time, the  stronger will  be the heat.   3.  That the
only method of producing a violent heat consists in burn-
ing bodies in the purest air.  4.  That fire and heat must
be more intense in proportion  as the air is more  con-
densed.  5. That currents of air are necessary to main-
tain and expedite combustion.  It is upon this principle
that the  theory  of the effects  of the  cylinder  lamps is
founded:  the current  of air, which  is  renewed  through
the tube,  supplies fresh air every  instant; and  by conti-
nually  applying a new quantity  of oxigenous gas to the
flame,  a heat is produced sufficient to ignite  and destroy
the smoke.
   It is likewise on the  same principle that we explain the
great difference that exists between heat produced  by  a 
VITAL AIR.
105
slow combustion,  and that which is  afforded by rapid
combustion.  In the latter case the same quantity of heat.
and light is produced in a second,  which might have been
produced in the other case in a much longer time.
  The phenomena of combustion, by means of oxige-
nous gas,  depend likewise upon the same laws.  Profes-
sor Lichtenberger,  of Gottingen,  soldered the blade of a
knife to a watch spring by  means of oxigenous gas;
Messrs. Lavoisier and Ehrmann have subjected almost all
the known bodies to the  action of  fire maintained by oxi-
genous gas alone; and they produced  effects which the
burning glass could not have operated.
   Mr. Ingenhousz has shewn us,  that if an iron wire be
bent into a spiral form,  and any  combustible substance
whatever be fixed to one of its ends, and set on fire, the
wire will itself  be fused by plunging  it into  oxigenous
gas.
   Mr. Forster, of Gottingen, found that the light of glow-
worms is so beautiful and bright in  oxigenous  gas,  that
one single insect was sufficient to afford light to read the
Annonces Savantes of Gottingen, printed in a very small
character.*  Nothing more is wanting therefore than  to
apply this air to combustion with facility  and economy;
and Mr. Meusnier has succeeded in this, by constructing
a simple  and  commodious apparatus.   On  this  subject
the treatise of  Mr. Ehrmann  upon fusion may be con-
sulted.
   The description of the gazometer may likewise be seen
in the Elementary Treatise of Chemistry, by Mr. Lavoi-
 sier, f
   We shall distinguish three states  in the  very act  of
combustion—ignition, inflammation, and detonation.

   *  The fire-fly and glow worm  of  America  produce no  such
effect.—Am. Ed.
   t  The highest degree of heat is produced by the flame of hy-
 drogene gas, urged by  oxigene air.
   An ingenious  apparatus for this purpose, superior to any thing
 of the kind they have in Europe, has been invented by Mr. Ro?
 bert Hare, junior, of this city.   An account of it may be seen in
 Tilloch's Philosophical  Magazine,  and in the fifth volume of the
 American Philosophical  Transactions.—Am. Ed.
                           Q 
106
VITAL AIR.
  Ignition takes place when the combustible body is not
in the aeriform  state, nor  susceptible  of assuming that
state by the  simple  heat  of combustion.   This  happens
when well-made  charcoal is burned.
  When the combustible body is presented to oxigenous
gas,  in the form of vapour or gas, the result is flame;
and the flame is more considerable,  in  proportion as the
combustible body is more volatile.  The flame of a can-
dle is not kept up but by the  volatilization  of the wax,
which is continually effected by the heat of  the combus-
tion.
  Detonation is a speedy and rapid inflammation, which
occasions a noise by the instantaneous formatoin of a va-
cuum.   Most detonations are produced by the mixture of
hydrogenous and oxigenous gas, as I have shewn in my
Memoir  upon Detonations,  in the year 1781.   It has been
since proved, that the product of the rapid combustion of
these two gases is .water.   Very strong detonations may
be produced by burning a mixture of one part of oxige-
nous  gas with two of hydrogene.   The effect  may be
rendered still more  terrible, by  causing the mixture to
pass through soap-water,  and setting fire to  the  bubbles
which are heaped on the  surface of the fluid.
  Chemistry presents several cases in which  the detona-
tion arises from  the  sudden formation  of some  gaseous
substances, such as that which is produced by the inflam-
mation of gunpowder; for in this case there is a sudden
production of carbonic acid, of nitrogene gas, &c.  The
production or instantaneous creation of  any gas whatever,
must occasion a  shock or agitation in the  atmosphere,
which necessarily affords  an explosion;  the effect of these
explosions increases, and becomes stronger,  from the op-
position of any obstacles  against the escape of the gas.
  C. Oxigenous gas is the only gas proper for respira-
tion.  It is  the most eminent property  which has entitled
it to the  name of Vital Air; and we shall give  the pre-
ference to this denomination in the present article.
  It has long since  been  known that animals cannot  live
without the  assistance of air.   But the phenomena of res-
piration have been very imperfectly known until  lately.
  Of all the authors who have written concerning respi-
ration, the ancients are those who have had the most ac- 
VITAL  AIR.
107
 curate ideas of it.  They admitted in the air a principle
 proper to nourish and support life, which they denoted by
 the name of pabulum  vita ; and Hippocrates expressly
 says, spiritus etiam alimentum  est.   This  idea, which
 was connected with no hypothesis, has been  successively
 replaced by systems void of  all foundation.  Sometimes
 the air has been considered as a stimulus in the lungs,
 which kept up the circulation by its continual action.
 Vide Haller.—Sometimes the lungs have been considered
 as bellows designed to cool the body,  heated by a  thou-
 sand imaginary causes : and when it was proved that the
 volume of air  was diminished in the lungs, it was thought
 to be an explanation of every difficulty, to  say that the
 air was deprived of its spring.
    At this day,  however, we are enabled to throw some
 light on one of the most important functions of the hu-
 man body.  In order to  proceed with more  perspicuity,
 we shall  reduce our notions to several principles.
    1. No animal can live without the assistance of air.
 This fact is universally  admitted;  but it has  not been
 known until lately that the faculty which the air possesses
 of answering the purpose of respiration, arises only  from
 one of the principles of atmospheric  air, known by the
 name of  vital air.
    2. All animals do not require the same purity in the
 air.  Birds, as well as men, and the greatest part of qua-
 drupeds, require a very pure  air; but those which live in
 the earth, or which hide themselves in a state  of stupe-
 faction during the winter,  can subsist by means of a less
 pure air.
   3. The manner of respiring the air is different in the
 several subjects.   In general,  nature has given to animals
 an organ, which by its involuntary dilatation and contrac-
 tion  receives and expels the  fluid in which  the  animal
 moves and exists.  This organ  is more  or less perfect,
 more or less concealed and defended from external injury-,
 according to its importance, and influence upon the life of
 the creature, as Mr. Broussonnet has observed.
   Amphibious animals respire by means of  lungs:   but
 they can suspend their motion even whilst they are in
the air; as I have observed with regard to frogs,  which
stop their respiration at pleasure. 
108
VITAL AIR.
   The manner of respiration in  fishes is very different;
these animals come from time to time to inhale the air at
the surface of the water, where they fill their vesicle, and
digest it afterwards at their ease.   I have for a long time
observed the phenomena of fishes in the act of respiration;
and am well assured that they are sensible of the action
of all die gases, like other animals.  Mr. De Fourcroy has
observed that the air contained in the vesicle of the carp
is nitrogene gas (phlogisticated air).
   Insects with tracheae exhibit organs still more remote
from ours in their construction.   In these animals, respi-
ration is effected by the tracheae distributed along the bo-
dy.   They accompany all the vessels, and terminate by
losing themselves in insensible pores  at the surface of the
skin.
   These insects appear to me to  exhibit several very evi-
dent points of analogy with vegetables.
   I.  Their respiratory  organs are  formed in the same
manner,  being disposed through the  whole body of the
vegetable and  the  animal.—2. Insects do not require a
great degree of purity in the air;  and plants are nourished
with atmospherical  mephitis.*—3.   Both the one  and the
other transpire vital air.  The abbe  Fontana discovered
several insects in stagnant waters,  which, when exposed
to the sun, afforded vital air:  and the green matter which
is  formed  in  stagnant  waters, and is by Dr. Priesdey
placed among the confervae, in  conformity with the opi-
nion of his friend Mr. Bewley—which Mr. Senebier has
supposed to be the conferva cespitosa fits rectis  undiaue
divergentibus Halleri, and which has appeared to Dr. In-
genhousz to be nothing else but  a  mass of animalcula—
affords a prodigious qu-intity of this air when exposed to
die  sun.—4.  Insects  likewise afford, by chemical analy-
sis, principles similar to those of plants, such as resins,
volatile oils, &c.

   * This is by no means true.  When a plant is made to grow in
atmospheric air, it always dies when the oxigenous portion of this air
disappears—Am, Ed. 
VITAL AIR.
109
  Father Vaniere appears to have  known, and very ele-
gantly expressed, the property of vegetables to support
themselves by means of vital air:

      .... Arbor enim (res non ignota,) ferarum
      Instar et halituum, piscisque latentis in imo
      Gurgite, vitales et reddit et accipit auras.
                               Proedium Rusticum, 1. vi.
                                                    r
  Animals with lungs respire  only by virtue of the  vital
air which surrounds them.  Any gas deprived of this mix-
ture becomes immediately  improper  for respiration; and
this function  is exercised with so much the greater liberty,
as vital air exists in a  greater proportion in the air re-
spired.
  Count Morozzo placed  successively several full-grown
sparrows under a glass bell, inverted over water.   It was
at first filled  with atmospherical air, and  afterwards with
vital air.  He observed—
  1.  In atmospherical air,
                               Hours. Min.
       The first sparrow lived    3    0
       The second     -     -    0    3
       The third     -     -      0    1
The water rose in the vessel eight lines during the life of
the first;  four during the life of die second;  and the third
produced no absorption.
  2. In vital air,
	Hours.	Min.
The first sparrow lived	5	23
The second	2	10
The third -	1	30
The fourth	1	10
The fifth	0	30
The sixth	0	47
The seventh -	0	27
The eighth	0	30
The ninth	0	22
The tenth	0	21
  From these experiments it may be concluded, 1.  That
an animal lives longer in vital air than in atmospherical
air.  2. That an animal canTive  in air in which another
has died.   3.  That, independent of the nature of the air, 
110
VITAL AIR.
respect must be had to the constitution of the animals, as
the sixth lived forty-seven minutes,  and the fifth  only
thirty.   4. That there is either an absorption of air, or the
production of a new kind of air, which is absorbed by the
water as it rises.
   It remains, at present, to examine what are the changes
produced by respiration.   1. In the air.   2. In the blood.
   The gas emitted by expiration is a mixture of nitrogene
gas, carbonic acid, and vital air.   If the air which issues
from the lungs be made to pass  through lime-water, it
renders it turbid;  if it be received through tincture of turn-
sole, it reddens it; and if a pure alkali be substituted in-
stead of the tincture of turnsol, it becomes effervescent.
   When the carbonic acid has been absorbed by the fore-
going process, the remainder of this air consists  of nitro-
gene gas and vital air.  The vital air is  shewn to be pre-
sent by means of  nitrous air.  The air  in which I had
caused five sparrows to perish, afforded seventeen hun-
dredth parts of vital  air.   After having thus deprived the
expired air of all its  vital air, and all its carbonic acid, the
remainder is nitrogene gas.
   It has been observed  that frugivorous animals vitiate
the air less than carnivorous animals.
   A portion of the air is absorbed in respiration.   Borelli
formerly took notice of this; and Dr. Jurin had calculated
that a man inspired forty cubic inches  of air in his  usual
inhalations,  and that in the greatest  he could  receive two
hundred and twenty inches; but that a portion was always
absorbed.   The celebrated Dr. Hales  endeavoured to de-
termine this absorption more strictly, and he estimated it
at a sixty-eighth of  the total of the  respired air; but he
did not "consider it as more than a hundred and thirty-sixth,
on account of errors which he  supposed to  have taken
place.   Now a man respires twenty times in a minute, and
inhales forty cubic inches of air at each inspiration: this
makes forty-eight thousand per hour;  which, divided by
one hundred and thirty-six, gives about three hundred and
fifty-three inches of air absorbed and destroyed in the hour.
The process of Hales is not exact; because he passed the
air expired through water, which must have  retained a
sensible proportion. 
VITAL AIR.                  HI
  From more accurate experiments, Mr. De La Metherie
lias proved, that three hundred and sixty cubic  inches of
vital air are absorbed in an hour.
  My experiments have not shewn near so great a loss.
  This fact affords a proof of the facility  with which air
is vitiated by respiration when it is not renewed, and shews
why the air of theatres is in general so unwholesome.
  II. The first effect  which the air appears to produce
upon the blood is, that of giving it a vermilion-colour.  If
the  blackish venous blood be exposed in  a  pure atmos-
phere, it  becomes of a vermilion-colour  at its surface:
this fact is daily observed when blood is suffered to remain
exposed in a porringer to the air.  Air which has remained
in contact with blood  extinguishes  candles, and precipi-
tates lime-water.   Air injected into a determinate portion
of  a vein between two ligatures, renders the blood of a
higher colour according to the fine  experiments of Dr.
Hewson.
  The blood which returns from die lungs is of a higher
colour, according to the  observations of Messrs. Cigna,
Hewson, &c.   Hence  arises the great intensity of the co-
lour of arterial blood, compared with venous blood.
  Mr. Thouvenel has proved, that by withdrawing the air
which is in contact with  the blood, it may be again made
to lose its colour.
   Mr. Beccaria exposed blood in a vacuum, where it re-
mained black,  but assumed the most beautiful vermilion-
colour as soon as it was again exposed  to the air.  Mr.
Cigna covered blood with oil, and it preserved its black
colour.
  Dr. Priestley caused the blood of  a sheep to pass suc-
cessively into vital air, common air, mephitic air, &c. and
he  found that the blackest parts assumed a red  colour in
respirable air,  and that  the intensity of tiiis colour was
in  proportion to the  quantity of  vital air  present.  The
same philosopher filled a bladder with blood, and exposed
it to pure air.   That portion of blood which touched the
surface of the bladder,  became red, while the internal part
remained black: an absorption of air therefore took place
through the bladder,  in the  same manner as when the con-
tact is immediate. 
112
VITAL AIR.
  All these facts incontestably prove,  that the vermilion-
colour assumed by the blood in the lungs, is owing to the
pure air which combines with it.
  The vermilion-colour of blood is therefore the first ef-
fect of* the contact,  absorption, and combination of pure
air with the blood.
  The second effect of respiration is to establish a real fo-
cus of heat in the lungs; which is a circumstance very
opposite to the precarious and ridiculous notion of those
who have considered the lungs as a kind of bellows de-
signed to cool die human body.
  Two celebrated physicians, Hales and Boerhaave, have
observed  that the blood acquired heat in passing through
the lungs; and modern physiologists have estimated tiiis
augmentation of heat at eleven hundredths.
  The heat in each class of individual animals is propor-
tioned to  the  magnitude  of  their lungs, according to
Messrs. De Buffon and Broussonet.
  Animals with cold blood have only one auricle and one
ventricle, as Aristotle observed.
  Persons who have respired vital air, agree in affirming
that they perceived a gentle heat vivifying the lungs, and
insensibly extending from  the breast into all the other
parts of the body.
  Ancient and modern facts unite therefore to prove, that
a focus of heat really exists in  the  lungs,  and that it is
maintained and kept up by the air of respiration.  We
are able, at present, to explain all these phenomena.   In
fact there is an absorption of vital air in respiration. Re-
spiration then  may be considered as an operation  by
means of which vital air passes continually from the ga-
seous  to the concrete  state:  it must therefore at each in-
stant abandon the heat which held  it  in solution, and in
the state of gas.  This heat produced at  every inspira-
tion must be proportioned to the  volume of  die  lungs, to
the activity of this  organ, to the purity of  the  air, the ra-
pidity of the inspirations, &c.   Hence it follows that, dur-
ing the winter, the heat produced must be more conside-
rable, because the  air is more condensed, and exhibits
more vital air under the same volume.  By the same rea-
son, respiration ought to produce more heat in the inha-
bitants of northern  climates; and this is one of the causes 
VITAL AIR.
113
 prepared by nature to temperate, and continually balance,
 the extreme cold of these climates.  It follows  likewise
 that die lungs of asthmatic persons are less capable of di-
 gesting the air ; and I am assured that they emit the air
 without vitiating it: from which cause their complexion
 is cold, and their lungs continually languishing;  vi'v.1 air
 is therefore wonderfully comfortable to them.  It may be
 easily conceived from these  principles  why the heat  of
 animals is proportioned to the volume of tiieir lungs; and
 why those which have only one auricle, and one ventricle,
 have cold blood, he.
  The phenomena of respiration are  therefore the same
 as those of combustion.
  Vital air, by combining with the blood, forms the car-
 bonic acid, which may  be considered as antiputrescent as
 long as it remains in the circulation; and that it is after-
 wards emitted through  the pores of the skin, according
 to the experiments of the count De Milly, and the obser-
 vations of Mr. Fouquet.
  Vital air has been used with success in  certain disor-
 ders of the human body.   The  observations of Mr. Cail-
 lens .?e well  known.  He caused persons affected with
 phthisical disorders to respire it with the greatest success.
 I have myself been a witness to the most  wonderful ef-
 fects of this air in a similar case.   Mr. De B---------
 was in the last stage of a confirmed phthisis.  Extreme
 weakness, profuse sweats, a flux of the belly, and in short
 every symptom announced the approach  of death.  One
 of my friends, Mr. De P-----,  put him on a course of
 vital air.   The patient respired it with delight, and asked
 for  it with all  the  eagerness  of an infant at the breast.
During the time that he respired it he felt a  comfortable
heat, which distributed itself through all his limbs.  His
strength increased with  the greatest rapidity; and in six
weeks he was able to  take long  walks.   This  state of
health lasted for six months :  but after this interval he re-
lapsed ; and being no longer able to have recourse to the
 use of  vital air, because Mr. De P---------had depart-
 ed for Paris^r he died.—I am very far from being of opi-
 nion that the respiration of vital air ought to be considered
 as a specific,  in cases of this nature.  I am even in doubt
 whether this powerful air is perfectly adapted to  such cir- 
114
NITROGENE  GAS,  AZOTE,
cumstanees;  but it inspires cheerfulness, renders the  pa-
tient happy,  and in desperate cases it is most certainly a
precious remedy, which can  spread  flowers on the  bor-
ders of the tomb,  and prepare us in the  gentlest manner
for the last dreadful effort of nature.
   The absolute necessity of vital air in respiration,  ena-
bles  us to lay down positive principles for purifying the
corrupted air of any given place.  This may be done in
three ways.   The first consists in correcting the vitiated
air by  means of substances which are capable  of seizing
the noxious principles.  The second consists in displacing
the  corrupted  air,  and substituting fresh air in the room
of it;  as  is done by means of ventilators, the agitation of
doors, &c.   And the third consists  in pouring into the
mephitised atmosphere a new quantity of vital  air.
   The processes employed in purifying corrupted air, are
not  all certain in their effects.  The fires which are light-
ed for this purpose have no other advantage than to esta-
blish ascending currents,  and to burn unhealthy  exhala-
tions ; and perfumes do nothing more than  disguise the
bad smell, without changing the nature of the air, as the
experiments of Mr. Achard shew.               •
                    CHAPTER III.

Concerning Xiti'ogene Gas,  Azote, or  Atmospherical;
                      Mephitis.

   IT has been long since ascertained, that air which  has
    served the purposes of combustion and  respiration is
no longer proper for those uses:  the air  thus corrupted,
has been distinguished by the names of Phlogisticated
Air, Mephitised Air, Atmospherical Mephitis, he.  I call
it Nitrogene Gas,  for the reasons explained  in the preli-
minary discourse.
   But this residue of combustion or respiration is always
mixed with a small quantity of vital air and carbonic acid,
which must be removed in order to  have the nitrogene
gas  in  a  state of purity.  There are several methods 
OR  ATMOSPHERICAL
MEPHITIS.
115
•which may be used to  obtain  nitrogene  gas, in a  very
pure state.
   1. Scheele has taught us, that by exposing sulphure of
alkali, or liver of sulphur, in a vessel filled with atmos-
pherical air, the vital air is absorbed;  and, when the ab-
sorption  is complete,  the nitrogene gas remains pure.
   By exposing, in atmospheric air over mercury, a mix-
ture of iron filings  and  sulphur, kneaded together  with
water, Mr. Kirwan obtained nitrogene gas so pure,  that
it suffered no diminution by nitrous gas.   He deprived it
of all humidity, by successively introducing dried blot-
ting-paper into the vessel which contained it.  Care must
be taken to withdraw this air in time from the paste which
affords it; otherwise it will be mixed with hydrogene or
inflammable  gas,  which is  afterwards disengaged.   2.
When by any means, such as  the oxidation of metals,
the rancidity of oils,  the combustion of phosphorus, he.
the vital  air of  the atmosphere  is absorbed, the residue is
nitrogene gas.   All  tiiese processes  afford methods  of
gieater or less accuracy to determine die proportions  of
vital air and nitrogene gas in the composition of the at-
mosphere.
   3. This mephitis may likew ise be procured by treating
muscular flesh, or the well-washed fibrous part of blood,
with nitric acid in the hydro-pneumatic apparatus.   But
it must be carefully observed that these  animal matters
ought to be fresh.;  for if they have begun to be  changed
by the putrid fermentation, they afford carbonic acid mix-
ed with hydrogene  gas.*
   A.  This gas is improper  for respiration and  combus-
tion.
   B.  It mixes with  the other airs, without combining
with them.
   C.  It is lighter than the atmospheric air, the barometer
standing at 30. 46,  and Fahrenheit's thermometer at 60 :
the weight of nitrogene gas is to that of common air as
nine hundred and eighty-five to one thousand.
   D.  Mixed with vital air, in  the proportion of 78 to 22,
it constitutes our atmosphere.   The other principles which

  * Azotic *gas procured in this manner is generally contaminated
with nitrous air.—Am. Ed. 
116              ATMOSPHERIC  AIR.
analysis exhibits in the atmosphere, are Only  accidental,
and by no means necessary.f
SECTION VI.
Concerning the Mixture of Nitrogene and Oxigene Gas ; or of
                    Atmospheric Air.


      THE gaseous substances we have treated of seldom
       exist  alone and insulated; nature presents them
every where to our observation in a state of mixture  or
of combination.   In the first case these gases preserve the
aeriform state;  in the second they for the most part form
fixed and solid bodies.   Nature,  in its several  decompo-
sitions, reduces almost all the principles of bodies into
gas.   These new substances unite together, combine, and
from thence result compounds of considerable simplicity
in their principles, but which become complicated  by
subsequent mixtures and combinations.  We may follow
the operations of nature, step by step, without departing
from the plan we  have adopted.
   The mixture of about seventy-eight parts of nitrogene
 gas,  and twenty-two of oxigene, form this fluid  mass in
which we live.   These two principles are so well mixed,
 and each of  them is so  necessary to the support of the
 various functions of individuals which  live or  vegetate
 upon the globe, that they have not yet been found sepa-
rate and alone.
    The proportion of  these two gases is subject  to vari-
 ation in the mixture which forms the atmosphere:  but
 this difference depends only upon local causes;  and the
 most usual  proportion  is that which we have here men-
 tioned.

   t Combined with hydrogene it forms ammoniac, and with oxi-
 gene the nitric acid.—Ajn. Ed. 
ATMOSPHERIC  AIR.
117
  The characteristic properties of vital air are modified
by those of nitrogene  gas,  and these modifications even
seem to be necessary':  for if we were to respire  vital air
in its state of purity, it would quickly consume our life ;
and this virgin air  is no  more suitable to our existence
than distilled water.  Nature does not appear to have de-
signed us for the use  of  these principles in their greatest
degree of perfection.
  The atmospheric air is elevated several  leagues above
our heads, and fills the deepest subterraneous cavities. It
is invisible,  insipid,  inodorous, ponderous,  elastic,  &c.
It was the only gaseous substance known before  the pre-
sent epocha of chemistry;  and the infinite gradations of
all the invisible fluids which presented themselves so  fre-
quendy to the observation of philosophers,  were always
attributed to modifications  of the air.   Almost the whole
of what has  been written upon the air relates  only  to its
physical properties.  We shall confine ourselves to point
out the chief of these.
   A. Air is a  fluid of extreme  rarefaction,  obedient to
the smallest  motion :  the slightest percussion deranges it;
and  its equilibrium,  which is continually destroyed, is
continually endeavouring to restore itself.
   Though very fluid, it passes with difficulty through ori-
fices by means of  which grosser  liquids can easily  pene-
trate.  This has caused  philosophers to suppose that its
parts were of a branched form.*
   B. The  atmospheric  air  is invisible.   It refracts the
rays of light without reflecting them: for  it is without
sufficient proofs that  some philosophers  have  imagined
that large masses of this fluid are of a  blue  colour.
   It appears that the  air is inodorous itself; though  it is
the vehicle of odorant particles.
   It may be considered as insipid j  and when its contact
affects  us variously,  we ought to attribute it to  its  physi-
cal qualities.

   * This is a deception.  It  is true that the cohesive attraction ren-
 ders it difficult to displace any dense fluid from a capillary tube by
 the  intrusion  of air; but every experiment  of the air-pump, the
 condensor, and the barometer, shews with what facility the air passes
 through the smallest orifices.   T. 
118
ATMOSPHERIC  AIR.
   C. It was not until the middle of the last century that
its weight  was  ascertained  by  accurate  experiments.
The impossibility of supporting water in a tube open  at
the bottom, to a greater height than thirty -two feet, caused
Torricellius to suspect that an  external cause  supported
the liquid at that height,  and that it was not the horror of
a vacuum which precipitated the water  in the  barrels  of
pumps.  This celebrated philosopher filled a tube closed
at one of its extremities with mercury : he  reversed this
into a vessel filled with  the  same metal; and observed
that the mercury, after several  oscillations, constantly sub-
sided to the height of twenty-eight inches.   He immedi-
ately saw7 that  the  difference of elevations  corresponded
with the relative weights of these two  fluids,  wnich  are
in the proportion of fourteen to one.   The immortal Pas-
chal proved, some time afterwards, that liquids were sup-
ported at this elevation by a column of atmospherical air;
and he ascertained that their height varies according to the
length of the column which presses upon them.
   D. The elasticity of the  air is one of the  properties
upon which natural philosophers have  made the greatest
number of experiments ; and it has even been applied to
considerable advantage in the arts.
                    SECTION VII.

Concerning the Combination of Oxigenous Gas and  Hydrogene,
                   which forms Water.

        ATER has been long considered as an element-
         ary principle;  and when  accurate  experiments
had compelled chemists to class it among compound sub-
stances, a resistance and opposition wrere made to it, which
were not manifested when the  air, the earth, and the other
matters reputed to be elementary, were subjected to simi-
lar revolutions.   It seems to me,  however, that this  ana-
lysis is equally strict widi that  of air.   Water is  decom-
w 
          GENERAL PROPERTIES  OF WATER.      H9

posed by several processes ; it is formed by the combina-
tion of oxigene and hydrogene : and we find that all the
phenomena of nature and art conspire to prove the same
truth.  What more can be required to afford an  absolute
certainty  respecting any physical fact ?
  Water is contained in bodies in a greater or less quan-
tity, and may be considered in two states i  it is either in
the state of simple  mixture, or in a state of combination.
In the first case it renders bodies humid,  is perceptible to
the eye, and may be disengaged with the greatest facility.
In the second,  it exhibits no character which shews  that
it is in a state of  mixture.   It exists in this form  in  cry-
stals,  salts,  plants,  animals,  &c.  It is this water  which
the celebrated Bernard has called Generative Water;  and
of which he has  made  a fifth  element,  to  distinguish it
from  exhalative water.
   Water, existing  in a  state of combination  in  bodies,
concurs in imparting to them hardness and transparency.
Salts, and  most stony  crystals, lose their transparency
when they are deprived of their water of crystallization.
   Some bodies are  indebted to water for their fixity.  The
acids, for example, acquire fixity only by combining  with
water.
   Under these various points of view, water may be  con-
sidered as the general cement of nature.  The stones and
salts which are deprived of it,  become  pulverulent;  and
water facilitates the coagulation, re-union, and consistence
of the particles of  stones,  salts, &c. as we shall see in the
operations performed with plasters,  lutes, mortar, &c.
   Water, when disengaged from its combinations, and in
a state of absolute  liberty, is one  of the  most considera-
ble agents in  the  operations of this globe.   It bears  a
part in the foi mation and decomposition of all the  bodies
of the mineral kingdom :  it is necessary to vegetation and
to the free exercise of most of the functions of animal bo-
Tties; and it hastens and facilitates the destruction of these
bodies,  as soon as  they  are deprived of the  principle of
life.
   For a certain time water was thought to be a fluid earth.
The  distillation, trituration, and putrefaction of water,
which always left an earthy residue, afforded credit to an 
120        WATER  IN,THE  SOLID STATE.

opinion that it was converted into earth.   On this subject,
the works of Wallerius and Margraff may be consulted:
but Mr. Lavoisier has shewn that this earth arises  from
the wear of the vessels ;  and the  celebrated Scheele has
proved the identity of the nature  of this  earth with that
of the glass vessels in which the  operations were made.
So that the opinions of the philosophical world are at pre-
sent decided in this respect.
  In order to obtain accurate  ideas of a substance so ne-
cessary to be known, we will  consider  water under its
three different states of solidity, fluidity, and gas.
                    ARTICLE  I.

        Concerning Water in the State of Ice.

  Ice is the natural state of water, whenever it is deprived
of a portion of that caloric  with which  it is combined
when it appears in the  form of a liquid or gas.
  The conversion into ice is attended with several pheno-
mena which seldom vary.
  A. The first of all,  and at the same time the most ex-
traordinary, is a sensible  production of heat at the mo-
ment in which the water passes to the solid  state.  The
experiments of Messrs.  Fahrenheit, Treiwald,  Baume,
De Ratte,  leave no  doubt on this subject;  so tiiat the
water is cblder at the instant  of  congelation than the ice
itself.
  A slight agitation of the fluid  facilitates  its conversion
into ice, nearly in the same manner as the slightest mo-
tion very frequently determines the crystallization  of cer-
tain salts.   This arises,  perhaps,  from the circumstance,
that by this means the caloric,  which is  interposed be-
tween the particles,  and may oppose itseU' to the produc-
tion of the phenomenon,  may be expressed or disengaged.
In  proof of diis  opinion, it is seen that the thermometer
rises at die very same  instant, according to Fahrenheit.
  B. Frozen water occupies a larger space than fluid wa-
ter  : we are Indebted to the Acidemy del Cimento for the 
           WATER  IN THE  SOLID  STATE.     v   121

proofs of this truth.   In their experiments, bomb shells,
and the  strongest vessels, being filled with water, were .
burst into pieces by  the  congelation, of this fluid.   The
trunks of trees are split and  divided  with a loud noise,
as soon  as  the  sap freezes;  and so likewise  stones  are
broken in pieces the moment the water, with which  they
are impregnated passes to the state of ice.
   C.  Ice appears  to  be nothing more than a confused
crystallization.   Mr. De Mairan observed that the needle-
formed  crystals of ice unite in an angle of either sixty or
one hundred and twenty degrees.
   Mr. Pelletier observed, in  a piece of fistulous ice, cry-
stals in the form of flattened triangular prisms, terminated
by two  dehedral summits.
   Mr. Sage observes, that if a piece  of ice, which  con-
tains  water in its internal parts, be  broken, the water runs
out, and the internal cavity is found to be lined with beau-
tiful tetrahedral prisms, terminated in  four-sided prisms.
These prisms  are often articulated and crossed.  Vide
M. Sage, Annates de Chimie, torn. i. p. 77.
   Mr.  Macquart  has observed, that  when it snows  at
Moscow, and the atmosphere is not  too  dry, the air is
observed to be loaded with beautiful crystallizations re-
gularly  flattened, and as thin as a leaf of paper.  They
consist of an union of fibres which shoot from the same
centre to form six  principal  rays,  and these rays divide
themselves into small blades extremely brilliant: he ob-
served  several of these flattened  radii which were  ten
lines in  diameter.
   D. When water passes from the  solid to the liquid
state, it produces cold by the absorption of a portion of
heat,  as is confirmed by the fine experiments of Wilcke.
This production of cold by the fusion of ice,  is likewise
proved by the practice of the confectioners, who fuse cer-
tain salts with ice, in order to produce a degree  of cold
below 0.
   Ice is found in many places in great masses, known by
the name of Glacieres: certain mountains are constantly
covered with them, and the southern ocean abounds with
them.   The  ice formed by salt water affords fresh water
when melted;  and in several northern provinces water is
said to be concentrated by frost, to collect the salt it holds
                          Q 
122       WATER  IN THE LIQUID  STATE.

in solution.  I have likewise observed, that several  me-
tallic salts are precipitated by exposing their solutions to
a temperature sufficient to freeze them.   The ice  which
was  formed did  not  possess  the  characters of the salt
which had been dissolved.
  Hail and snow are nothing  but modifications of ice.
We  may consider hail as produced by the sudden disen-
gagement of the elastic fluid, which concurs in rendering
water liquid : it is almost always accompanied with thun-
der.   The experiments of  Mr. Quinquet have confirmed
this theory.—I will  here relate a fact  to  which I myself
was  witness, at  Montpelier, and  of  which philosophers
may advantageously avail themselves..  On the 29th of
October,  1786,  four inches of water  fell at Montpelier*
a violent explosion  of thunder,, which was heard about
four in the evening, and which appeared to be very near,
caused a most dreadful showrer of  hail.   At this instant  a
druggist, who was employed in his  cellar  in preventing
the mischief occasioned by the filtration  of water through
the wall, wras highly astonished to behold that the water
which came through the wall was  instantly  changed into
ice.   He called in several  neighbours to  partake of his
surprise.  I visited the place a quarter of  an hour after-
wrards and found ten pounds of ice at the foot of the wall;
I was well assured that it could not have passed through
the wall,  which did not exhibit any crack, but appeared
to be in very good  condition.   Did the same cause, which
determined the formation of hail in the  atmosphere, act
equally in this cellar ?—I relate the fact only, and forbear
to make any conjecture upon it.
                     ARTICLE n.

       Concerning  Water in the Liquid State.

     THE natural state of water appears to be that of ice;
      but its most usual state is that of fluidity; and un-
der this form it possesses certain general properties, which
we shall proceed to  describe.
 '  The experiments of the Academy del Cimento have
caused  the philosophical world to deny the least elasticity 
DISTILLATION  OE WATER.          123
^o water,  because it escaped through  the pores of balls
of metal strongly compressed,  rather than yield  to pres-
sure.  But Messrs. Zimmerman, and the abbe Mongez,
have endeavoured to prove its elasticity from the  very ex^
periments  upon which the  contrary  opinion has  been
built.*
  The liquid state renders  the force  of aggregation in
water less powerful,  and it enters into combination more
readily in this form.  Water which flows  on the surface
of our globe is never pure.   Rain-water  is seldom  ex-
empt from some mixture,  as appears from the fine series
of experiments of the celebrated  Margraff.   I have  as-
certained,  at Montpelier, that the rain-water in storms is
more impure than that of a gentle shower—that the  wa*
ter which falls first is less pure than that which falls after
several hours or several days rain—that the  water which
falls when the wind blows from the sea to the southward,
contains sea-salt;  whereas that which is  produced by a
northerly wind,  does not contain a particle.
   Hippocrates has made several very important observa-
tions respecting the various qualities of water, relative to
the  nature of the  soil, the temperature of the climate, &c.
   As it is of importance to the chemist to have very pure
water for several  delicate  operations, it  is  necessary to
point out the means which may be used to cany any wa-
ter whatever to this degree of  purity.
   Water is purified by distillation.   This operation is
performed in vessels called Alembics.  The  Alembic is
composed of two pieces; a  boiler or cucurbit, and a co-
vering called the capital or head.
 * The water is put into the cucurbit, from winch it is
raised in vapours  by means of fire, and these vapours are
condensed  by cooling the head  with  cold  water.  The
condensed vapours flow into a vessel designed  to receive
them.   This is called Distilled Water; and  is pure, be-

  *  The  experiments of Canton, to prove the  compressibility of
water, are well known, and may be seen in the Philosophical Trans-
actions.  He enclosed water in spherical glass vessels, from  which
a narrow neck proceeded, like  that of a thermometer :  the water
was found to occupy  a larger space when the pressure of the atmos-
phere was removed by the air  pump, and a  less space when £
greater pressure was added by the condensor.  T. 
124
DISTILLATION OF WATER-
cause it has left behind  it in the cucurbit the salts and
other fixed principles which altered its purity.
   Distillation is more speedy and quick, in proportion as
the pressure of the air  is less upon die surface of the
stagnant fluid.  Mr. Lavoisier distilled mercury in vacuo;
and the abb6 Rochon has made a happy application of
tiiese principles to distillation.   It is to this same princi-
ple that we  must  refer the observations of almost all  na-
turalists and philosophers, who have  remarked,  that the
ebullition in the liquid becomes more easy, in proportion
as we ascend a mountain from any other elevation; and
it is  in consequence of these principles, that Mr. Achard
constructed an instrument  to determine the  heights  of
mountains,  by the degrees of temperature of die ebulli-
tion  of boiling water.
   The abbe Mongez, and Mr. Lamanow, observed that
ether evaporates with prodigious facility upon the peak of
Teneriffe ; and Mr. De Saussure has confirmed these ex-
periments on the mountains of Switzerland.
   A true distillation is carried on every where at the sur-
face  of our globe.  The heat of the sun  raises  water  in
the form of vapours ; these  remain a certain time in  the
atmosphere, and  afterwards fall  in the form  of dew, by
simple  refrigeration.   This  rise  and fall of  humidity,
which succeed each  other,  wash and purge the atmos-
phere of all those particles,  which by their corruption  or
development might render it infectious; and it is perhaps
this combination of various  miasmata with water which
renders the  evening dew so  unwholesome.
   It is to a similar natural distillation that  we ought to re-
fer the  alternate  transition  of water from the liquid state
to that of vapour, which forms clouds, and by this means
conveys the water from the  sea to the summits  of moun-
tains, from  which it is precipitated in torrents, to return
again to the common receptacle.
   We find traces of the distillation of water in the most
remote ages.  The first navigators  in the islands of the
Archipelago filled their pots with salt-water, and received
the vapour in sponges placed over them.   The process of
distilling  the  water of  the  sea has been successively
brought to perfection; and Mr.  Poissonnier has exhibited 
WATER IN THE STATE OF CAS.
125
a very well constructed apparatus to procure fresh  water
at all times in abundance.
   Pure water requires to be agitated, and combined with
the air of the atmosphere, to render it wholesome.  Hence
no doubt,  it is,  that water  immediately produced by
melting snow, is unfit to drink.
   The characters of potable water are the following:
   1. A lively, fresh, and agreeable taste.
   2. The  property of boiling readily, and  also that of
boiling peas, and other pulse.
   3. The virtue of dissolving soap without curdling.


                    ARTICLE III.

         Concerning Water in the State of Gas.

       MANY substances are naturally in the state of an ae-
        riform fluid, at the degree of the temperature of
our atmosphere: such, for example, are the carbonic acid;
and the oxigenous, the hydrogenous, and the nitrogenous
gases.
   Other substances evaporate  at a degree  of heat  very
near that in which we live.  Ether and alcohol are in this
situation.  The  first of these liquors passes to the state of
gas at  the temperature of 35 degrees;  the second, at that
of 80 (of Reaumur.)
   Some fluids require  a  stronger heat for this purpose;
such as water, the sulphuric and nitric acids, oil, &c.
   To convert water into an aeriform fluid, Messrs. De la
Place and Lavoisier filled a glass vessel with mercury,
and reversed  it  over a dish filled  with  the same metal.
Two ounces of water were transferred beneath this vessel;
and the mercury was heated to the temperature of between
ninety-five  and a hundred of Reaumur, by plunging it in
a boiler filled with the  mother water of  nitre.  The in-
cluded water became rarefied,  and occupied the whole ca-
pacity.
   Water, by passing through earthen vessels ignited in the
fire, becomes converted into gas, according to  Priestley
and Kirwan.   The eolipile, the steam-engine,  the digest-
er of Papin,  and the process of the  glass-blowers,  who 
126           COMPOSITION OF  WATER.

blow large  globes  by  injecting  a mouthful of  wateT
through their iron tube, prove the conversion of water into
gas.
   It follows from diese principles, that the volatilization of
water being nothing  more than a direct combination of
caloric with this liquid, the portions of water  which  are
the most immediately exposed to  heat, must be the  first
volatilized:  and this  is daily observed; for it is  continu-
ally seen that ebullition begins at  the part  most heated.
But when the heat is applied equally at all parts, the ebul-
lition is generaL
   Several phenomena have led  us to believe that water
may be converted  into  air.   The process  of the glass-
blowers to blow large spheres; the hydraulic organ of fa-
ther Kircher-, the phenomena of the eolipile;  the experi-
ments of Messrs. Priestley and Kirwan; the manner of as-
sisting combustion, by sprinkling  a small quantity of water
upon the coals—all these circumstances appeared to  an-
nounce the conversion of water into air.  But it was far
from being  supposed that most of these phenomena were
produced by the decomposition of this fluid; and the ge-
nius of Mr. Lavoisier was necessary to carry this point of
doctrine to the  degree of certainty and precision, which in
my opinion  it now appears to possess.
   Messrs. Macquer  and De la Metherie  had already ob-
served, that the combustion of inflammable  air produced
much water. Mr. Cavendish confirmed these experiments
in England, by the rapid combustion  of inflammable air
and vital air.  But Messrs. Lavoisier, De la Place, Monge,
and Meusnier,  have proved that the whole  mass  of the
water might be converted into hydrogene and oxigene; and
that the combustion of these two gases produced a volume
of water proportioned to the weight of the two principles
employed in this experiment.
   1.  If a small glass vessel be inverted over mercury, and
a known quantity of -distilled water and filings of iron be
put into the upper part of this vessel, inflammable air will
be gradually disengaged, the iron will rust, and the water
which moistens it  will diminish, and at length disappear;
the weight of the inflammable air which is produced, and
the augmentation in weight of the iron, will  be equivalent
to the weight of the water made use of   It appears there- 
COMPOSITION OF WATER.
127
fore to be proved, that the water is reduced into two prin-
ciples, the one of which is inflammable air, and the other
is the principle which has entered mto combination with
the metal.  Now we  know that the oxidation or calcina-
tion of metals is owing to vital  air;  and consequendy the
two substances produced, namely the vital air and inflam-
mable air, arise from the decomposition of water.
  2.  When wrater is  converted into  the state  of vapour,
in its passage through an ignited iron tube,  the iron be-
comes oxided, and  hydrogene is obtained in the state of
gas.   The augmentation of weight in the metal, and the
weight  of the hydrogene obtained form precisely a sum
equal to that of the water employed.
   The  experiment made  at Paris,  in the presence of a
numerous commission of the Academy, appears to me to
leave no  further doubt concerning the decomposition of
water.
   A gun-barrel was taken, into which a quantity of thick
iron wire, flattened by hammering, was introduced.  The
iron and.thexgun-barrel were weighed: the gun-barrel was
then covered with a lute proper to defend it from the con-
tact  of the air;  it was afterwards placed in a furnace, and
inclined in such a manner as that water might run through
it.   At its  most elevated extremity  was fixed a funnel
designed  to contain water, and to let it pass drop by drop
by means of a cock: this funnel was closed, to avoid all
evaporation of the water.   At the other extremity of the
gun-barrel was placed a tubulated receiver, intended to re-
ceive the water which might pass without decomposition;
and  to the tubulure of the receiver the pneumato-chemi-
cal apparatus was adapted.  For greater precaution, a va-
cuum was made in the  whole  apparatus before the opera-
tion began.   Lastly,  as soon as the gun-barrel was red-
hot, the water was introduced drop by drop.   Much hy-
drogenous gas was obtained:  and  at the end of the expe-   %
riment the gun-barrel was found to have acquired weight;
and die flat  pieces of iron  included within were converted
into a stratum of black  oxide  of iron, or Ethiops martial,
crystallized like the iron ore of the island of Elba.  It was
ascertained  that the iron was  in the same state  as that
 which  is burned  in  oxigenous gas;  and the increased 
 12.8           COMPOSITION OF WATER.

 weight of the iron, added to that of the hydrogene, was ac-
 curately equal to that of the water employed.
   The hydrogenous gas obtained was burned with a quan-
 tity of vital air equal to that which had been retained by
 the iron, and the six ounces of water were recomposed.
   3.  Messrs. Lavoisier and De la Place, by burning in a
 proper apparatus a mixture of fourteen parts of hydroge-
 nous  gas,  and eighty-six of oxigene, obtained a proporti-
 onate quantity  of water.   Mr. Monge obtained the same
 result at Mezieres, at the same time.
   The most conclusive and the most authentic experiment
 which was made upon the composition or synthesis of wa-
 ter, is that which was begun on the 23d of May, and end-
 ed on the  7th of June, 1788, at the Royal College, by Mr.
 Lefevre de Gineau.
   The volume  of oxigenous gas consumed, when reduced
 to the pressure of twenty-eight inches of mercury,  at the
 temperature of ten degrees of die thermometer of Reau-
 mur,  was  35085 (French) cubic inches,  and its  weight
 250 gross 10,5 grains.
   The volume of hydrogenous  gas  was  74967,4 cubic
 inches, and the weight 66  gross 4,3 grains.
   The nitrogenous gas and the carbonic acid which were
 mixed widi these gases, and  which  had been extracted
 out of the receiver at nine several times, weighed 39,23
 grains.
   The oxigenous gas contained TTT of its weight of carbo-
 nic acid; so that the weight of  these  gases burned was
 280 gross 63,8 grains, which makes 2 pounds 3 ounces 0
 gross  63,8 grains.
   The vessels were opened in the presence of the gentle-
 men of the Academy of Sciences, and several  other learn-
 ed men, and were found to contain  2 pound 3 ounces 0
 gros 33 grains of water: this weight answers to that  of
 the gases made use of, wanting 31 grains;  this deficiency
may arise from the caloric  which held the  gases in solu-
 tion being dissipated when they became fixed, which must
necessarily have occasioned a loss.
  The water was subacid  to the taste, and afforded 274-
grains of nitric acid, which acid is produced by the com-
bination of the  nitrogene and oxigene gases.
  From the experiment of the decomposition of  water,
 100 parts of this fluid contained 
COMPOSITION OF WATEJl.
129
         Oxigene       84,2636 = 84|
         Hydrogene     15,7364 = 15^

According to the experiment of its composition, 100 parts
of water contained
         Oxigene       84,8  = 84f
         Hydrogene     15,2  = 15-J.

   Independent of these experiments of  analysis and syn-
thesis, the phenomena exhibited by water,  in  its several
states, confirm our ideas with regard to the  constituent
parts which we acknowledge it to possess.  The oxida-
tion of metals in the interior parts of the earth, at a dis-
tance from the atmospherical air, the  efflorescence of py-
rites, and the  formation of ochres, are phenomena which
cannot be explained without  the assistance  of this theory'.
   Water being composed of two known principles, must
act like all other compound bodies which we know; that
is, according to the affinities of its constituent parts.   It
must therefore in some instances yield its hydrogene, and
in others its oxigene.
   If it be  placed in contact with bodies which have the
strongest affinity  with oxigene, such as  the  metals, oils,
charcoal, he. the oxigenous principle will unite with these
substances; and the hydrogene, being set  at liberty, will
be dissipated.    This happens when hydrogene gas is
disengaged, by causing the acids to  act upon certain me-
tals;  or when red-hot iron  is plunged in water, as Messrs.
Hassenfratz, Stoulfz, and D'Hellancourt have  observed.
   In vegetables,  on the contrary, it seems that the hydro-
gene is  the principle  which fixes  itself;  while the oxi-
gene is easily disengaged, and makes its escape.
R 
130
COMBINATIONS OF NITROGENE GAS.
                    SECTION VIII.


Concerning the combinations of Nitrogene Gas.  1. With Hydrogene"
    Gas.  2. With the Earthy Principles forming the Alkalis.

   IT appears to be proved, that  die combination of nitro-
    gene gas with hydrogene forms one of the substances
comprised in the class of alkalis.   It is very probable that
the others are composed of this same gas and an earthy
basis.  It is from these considerations that we have thought
proper to place those substances here: and  we  have a-
dopted that decision with  so much the more  foundation,
because the knowledge of alkalis is indispensably neces-
sary to enable us to proceed  with order in  a course of
chemistry;  and because  these re-agents are most fre-
quently employed,  and their  combinations and uses pre-
sent themselves at every step  in the phenomena of nature
and art.
   It is an established convention  to call  every substance
an  Alkali, which  is characterized by the following pro-
perties:
   A. An acrid, burning,  urinous  taste.
   B. The property of converting  blue vegetable colours
green;*  but not the tincture of turnsol, as certain authors
announce.
   C. The virtue of forming glass, when fused with quart -
zose substances.
   D. The faculty of rendering oils miscible  with water;
of effervescing with certain acids;  and of forming neutral
salts with all of them.
   I must observe that none of these characters is rigorous
and exclusive; and that consequently no one of them is
sufficient to afford a certainty  of the existence of an alkali:
but the re-union of several form, by their concurrence,  a
mass of proofs or  indications, which lead us to sufficient
evidence.

   * Indigo is an exception to this law.  The alkalis have  no effect
upon this blue vegetable colouring matter,—-Am. E,d. 
VECETABLE FIXED ALKALI.
131
  The alkalis are divided into fixed  alkalis, and volatile
alkalis.   This distinction is established upon the smell of
these substances: the former are not volatilized, even in
the  focus of the burning mirror, and emit no characteristic
smell;  whereas the  latter are  easily reduced into vapour,
-md emit a very penetrating odour.
                     CHAPTER I.

               Concerning Fixed Alkalis.

      NO more than two kinds of fixed alkalis have hitherto
      been discovered: the one which is called Vegetable
Alkali, or Potash; the other Mineral Alkali, or Soda.


                      ARTICLE I.

      Concerning the Vegetable Alkali, or Pot-Ash.

   This alkali may be extracted from  various substances;
and it is more or less pure, accordingly as it is afforded
by one substance or another.    Several varieties are made
in commerce, to which different names have been affixed,
and which are indispensably necessary to be known. The
chemist may indeed  confound all these distinctions, in his
writings, under one single denomination: but the distinc-
tions established by  the artists  are founded upon a series
of experiments, wliich have  proved  that the virtues of
these  several alkalis are very different;  and this constant
variety in their effects appears to me to justify the various
denominations assigned them.
   1. The alkali extracted from  the  lixivium of wood-
ashes, is known by the name of  Salin.  The salin cal-
cined, and by this means disengaged from all the blacken-
ing principles, forms potash. 
132
VEGETABLE FIXED ALKALI.
   The ashes are more or less  rich in alkali, according to
the nature of the wood which affords them; in general,
hard woods contain the most.*   The ashes of beech af-
ford from 11 to 131b. per quintal, according to the expe-
riments which  I have made in the large  way, at St. Sa-
veur;  those of box afforded from 12 to 141b.  The tables
drawn up by the several administrators of the gunpowder
and saltpetre manufactories may  be consulted, respecting
the quantity of alkali afforded by  the combustion of seve-
ral plants : they used 40001b. of  each in their various ex-
periments, f
   To  extract this alkali, nothing  more  is necessary dian
to wash the ashes, and to concentrate  the dissolution in
boilers of cast iron.   It is on account of the alkali, that
wood-ashes are employed in the lixiviums used  by laun-
dresses or bleachers.   The use of alkali, in this case, is to
combine with the fat substances, and to render them so-
luble in water.
   Almost all the potash sold in commerce  for the use of
our glass-houses, our soap-makers, our bleaching-grounds,
&c.  is fabricated in the north,  where  the abundance of
wood admits of its been applied to this single purpose. We
might establish works of this kind to sufficient advantage
in the  forests of our kingdom.   But there is more  to be
done than is generally supposed,  before  the inhabitants of
the mountains can be turned towards this species of in-
dustry.  I have experienced this difficulty in the attempts,

  * Fourcroy says, more potash is generally extracted from  tender
than from hard wood.  There is more from the rind of fruits, than
from any other parts.—Am, Ed.
  t According to these experiments,
                                 Pounds. Ounces. Drachms. Grains.
Turn sol yielded	80	0	0	0
Indian Corn	70	8	6	13
Tendrils of vines	23	4	4	0
Elm	15	10	4	0
Willow-tree	11	9	6	18
Box-wood -	8	15	7	48
Oak	6	2	3	44
Beech	5	13	4	42
Horn-bean	a	0	1	69
Aspin	3	0	1	13
Pine or Fir-tree -	1	5	2	6 ' Am. Ed.
 
VEGETABLE FIXED ALKALI.
133
and very considerable sacrifices which I have  made, to
secure this  resource  in  the neighbourhood of Laigoual
and Lesperou.   The accurate calculations which I have
made, have nevertheless  proved that the potash would cost
only from 15 to  17 livres  the  quintal, whereas we pur-
chase that from the north at 30 or 40 livres.
   2.  The lees of wine are almost totally converted into al-
kali by combustion.  This alkali is called Cendres Grave-
lees: it has almost always a greenish colour.   This alkali
is considered as very pure.
   3.  The combustion of tartar of wine likewise affords an
alkali of considerable purity.   It is usually burned wrap-
ped up in  paper, in small packets, which are dipped in
water, and afterwards exposed upon burning  coals.   In
order to purify it, the residue  of the  combustion  is dis-
solved in water,  the solution  concentrated  by fire, the fo-
reign salts separated in proportion as they precipitate;
and a very pure alkali is at last obtained, which is known
 by the name of Salt of  Tartar.
   ' To procure salt of tartar more speedily, as well as more
 economically, I burn a mixture of equal parts of nitrate of
 potash,  or common nitre and tartar.   The residue, after
 lixiviation, affords a beautiful salt of tartar.
   Salt of tartar is the alkali most  commonly employed in
 medical uses; it is given in the dose of several grains.
   4. If saltpetre be fused upon charcoal, the acid is decom-
 posed and dissipated, while  the  alkali remains alone and
 disengaged:  this is called  Extemporaneous Alkali.*
    When the vegetable alkali has been brought to the great-
 est state of purity, it attracts  the humidity of the air, and
 is resolved into  a liquor.   In this  state it is known by the
 very improper.name of Oil of Tartar per deliquium.

   *  In this case the carbone combines with the oxigene of the nitric
 acid of the nitre, and forms carbonic acid gas, which with the azotic
 air of the acid flies off.  The potash of  the nitre  remains behind.—
 Am. Ed. 
134
MINERAL FIXED ALKALI.
                      ARTICLE II.

        Concerning the Mineral Alkali, or Soda.

   The Mineral Alkali has been so called, because it forms
die basis of marine salt.
   It is obtained from marine plants by combustion:  for
this purpose heaps of die  saline plants are  formed;  and
at the  side of these heaps a round cavity is dug,  which is
enlarged towards the bottom, and is three or four feet in
depth: this is the fire-place in which the vegetables are
burned.   The combustion is kept up without interruption
for several days; and when all the plants  are consumed, a
mass of alkaline salt is found remaining, which is cut into
pieces, to facilitate its carriage and sale.   This  is known
by the name of Rock Soda, or Soda.
   All  marine plants do not afford soda of the same qua-
lity.   The barilla of  Spain affords  the beautiful soda of
Alicant.   I am assured that we  might cultivate it upon
our coasts in the Mediterranean, with the greatest success.
This culture is highly interesting to the arts and commerce;
and government ought to encourage  this new species of
industry.   But an individual, however inclined or devoted
to the public good, might make vain efforts to appropriate
this commerce to our advantage, if he were not powerful-
ly assisted by  government; because the Spanish ministry
has prohibited the exportation of the seed of barilla, under
the strongest penalties.   In Languedoc, and in Provence,
we cultivate on the banks of our ponds a plant known by
the name  of Salicor, wnich affords soda of a good quality;
but the plants which grow without cultivation produce an
inferior sort.  I have made an accurate analysis of each
species, the results of which may be seen at the article Ver-
rerie of the Encyclopedic Methodique. *

  * Mr. Henry Mackenzie has given an account of the mode of mak-
ing soda in  Scotland, in an essay published in the prize essays and
transactions of the Highland Society.
  He informs us that the whole soda of Scotland is in general afford-
ed by the four following plants;
  First. Eucus vesiculosus, the most common sea-wrack,  called also
the sea-oak, from the resemblance of its leaves to those of the oak. 
MINERAL  FIXED ALKALI.
135
  The mineral alkali is cleared of all heterogeneous salts
by dissolving it in water, and  separating the  several salts
in proportion as they fall down.  The last portion of the
fluid being concentrated  affords the soda,  which  crystal-
lizes in rhomboidal octahedrons.
  The mineral alkali is sometimes found in a native state:
in Egypt it is known by the name  of Natron.  The two
lakes of Natron described by Sicard and Mr. Volney, are
situated in the desert of Chaiat, or St. Macaire, to the west
of Delta.   Their bed is a natural cavity of  three or four
leagues in length, and  a quarter of a league in breadth;
the bottom  is  solid and stony.   It is  dry  during nine
months in the year; but in winter  a water of a violet-red
colour oozes out of the  earth, which fills the lake to five
or six feet in depth: the return  of the  heat of summer
evaporates this, and leaves a bed of salt behind it of two
feet in thickness,  which is dug out with  bars of iron.
The  quantity obtained annually amounts to  36,000 quin-
tals.
   Mr.  Proust found natron upon  the schisti which form
the foundation of the town of Angers; the  same chemist
likewise  found it upon  a stone  from the saltpetriere  of
Paris.
   The mineral alkali differs from the vegetable,  because
—1. It is less caustic.   2. It is so far from attracting hu-
midity, that it effloresces in the air.  3.  It crystallizes in
rhomboidal octahedrons.   4.  It forms different products
with the same bases.   5.  It  is  more proper for Nitrifica-
tion.
   Do the alkalis exist ready formed in vegetables,  or  are
they the product of the  several operations made use of in
extracting  them?—This  question has divided the opi-

  Secondly.  Fucus nodosus, knotted sea-wrack.
  Thirdly. Fucus aerratus, the jagged or serrated sea-wrack ; and
  Fourthly.  E"ucus digitatus, or tangle.
  These four plants are rooted upon rocks or stones.  They grow
only on the shores, where they are entirely uncovered by the water at
the lowest ebb.
   In Spain soda is procured from the salsola soda, and salsola salicornia
and batis maritima. The zostera maritima is burnt for this purpose on
the borders of the Baltic.   In France they use the c/ienopodium mari-
tirhum, and in the Canary islands the mesembryanthemum chrystallinuni}
or ice plant is cultivated for this purpose___im. Ed. 
13G
MINERAL  FIXED ALKALI.
nions of chemists.   Du Hamel and Grosse  proved, in
1732,  the existence of  alkali in cream of tartar, by treat-
ing it with the nitric, sulphuric, and other  acids." Mar-
graff has  given additional proofs of this, in a  Memoir
w hich forms the  twenty-fifdi  of his  collection.   Rouelle
read a Memoir to the academy on the 14th of June, 1769,
upon the same subject:  he even affirms that he was ac-
quainted with this truth before the work of Margraff ap-
peared.—See die Journal  De Physique, vol. i.
  Rouelle, and the marquis De Bullion, proved that tar-
tar exists in must.
  It must not be concluded from the existence of an al-
kali  in  vegetables,  that this salt is there found in a disen.
gaged state.   On the contrary it is found combined with
acids,  oils,  &c.
  The  alkalis, such as we have described them, even af-
ter they have been disengaged from every mixture, by so-
lution,  filtration,  and evaporation,  are not nevertheless in
that  state of purity  and  disengagement,  wiiich is necessary
to be obtained in many cases : they are nearly in the state
of neutral salts, by their  combination with the carbonic*
acid.  When it is required to disengage this acid, die al-
kali  must be  dissolved in water, and quick  lime dien
slaked  in  the  solution.  This substance seizes the  car-
bonic acid of the alkali, and gives out  its  caloric in  ex-
change.   We  shall speak  of the  circumstances of this
operation when we shall have  occasion to treat  of lime.
The alkali being deprived of  the carbonic acid, no longer
effervesces with other acids :  it is more caustic, and more
violent  in its action;  unites more easily to  oils; and  is
then called Caustic  Alkali,  Pure Potash,  or Pure Soda.
  When this alkali is evaporated,  and brought  into the
dry fonn, it is known by the  name  of Lapis  Causticus.
The corrosive virtue of this substance depends principally
upon the avidity with which it seizes humidity,  and  falls
into  deliquium.
  The  caustic alkali,  as  it is usually prepared, always
contains a small quantity of carbonic acid, silicious earth,
iron, lime,  &c.  Mr. Berthollet has proposed the follow-
ing means of purifying it:—He concentrates the caustic
lixivium until it has acquired a slight degree of consist-
ence ;  at which period he mixes it with alcohol, and draws 
LIVER OF SULPHUR.
137
off a portion by distillation.  As soon as the retort is be-
come cold,  he  finds it to contain crystals,  mixed with a
blackish earth,  in a small quantity of liquor of a dark co-
lour, which is separated from the solution of alkali, in the
alcohol, which swims above like an oil.  These crystals
consist of the alkali saturated with the carbonic acid, and
are insoluble in spirit of wine ;  the deposition consists  of
silicious earth,  lime, iron,  &cc.
  The  caustic alkali in a state of great purity,  dissolved
in the alcohol,  swims above the  aqueous solution  utiich
contains the effervescent alkali.   If the spirituous  solu-
tion of  alkali be concentrated on the sand-bath, transpa-
rent crystals are formed, which consist of the pure  alkali
itself, these crystals appear to be formed by quadrangular
pyramids inserted one in another;  they are very deliques-
cent, are soluble  in water and  in alcohol,  and produce
cold  by their  solution.—See  the Journal de  Physique,
 1786, page 401.
   The alkalis  we have just spoken, of, combine  easily
 with sulphur.
   This combination may  be effected—1. By the fusion
 of equal parts of alkali and sulphur.  2. By digesting the
 pure and liquid alkali upon sulphur.—In these cases  the
 alkali becomes of a reddish yellow colour.
   The solutions of sulphur in  alkali  are  known by  the
 name of  Livers  of Sulphur,  Sulphures  of Alkali, &c.
 They emit an offensive  smell,  resembling  that  of  rotten
 eggs.  This is occasioned by  the escape of the  stinking
 gas, called Hepatic Gas.
   The sulphur may be precipitated by acids; and the re-
 sult of this precipitation is what the ancient chemists dis-
 tinguished by the name of Milk of Sulphur, and Magis-
 tery of Sulphur.
   These sulphures or hepars dissolve metals.   Gold itself
 may be so divided by this means as to pass through  ni-
 tres.   Staid has supposed that Moses made  use of this
 method to enable the Israelites to drink the golden  calf.
   Though the analysis of the  two alkalis  has  not been
 made with strictness, several experiments lead us  to  be-
 lieve that nitrogene is one of their principles.  Mr.  Thou-
 venel,  having exposed washed chalk to the exhalations of
 animal substances in putrefaction, obtained nitrate  of pot:
                           S 
138
COMPOSITION  OF  ALKALI.
ash, or common nitre.  I have repeated this experiment
in a closed chamber  of  six feet square.   Twenty-five
pounds of chalk wrell washed in warm water, and exposed
to the exhalation of bullock's blood in putrefaction during
eleven  months, afforded nine ounces of nitrate of lime, in
a dried state ;  and three ounces one  gross  of crystals of
nitrate  of pot-ash, or common nitre.
   The repeated distillation of soaps decomposes  them,
and affords ammoniac.   Now the analysis of this last, by
Mr. Berthollet, proves the existence  of nitrogenous gas
as one  of its constituent parts.  There is therefore room
to apprehend that nitrogene gas is one of the principles of
alkalis.
   The experiments  of Mr, Thouvenel, as well as my
own, lead to believe that this  gas wiien combined with
lime, forms pot-ash, or  the  vegetable alkali; while its
union with magnesia forms soda.   This last opinion is
supported  by  the  experiments—1.  Of Define, who ob-
tained  magnesia from soda (see Crelf's Chemical Annals,
1781,  page S3).   2. Of Mr. Deyeux,  who obtained si-
milar results, even before Mr. Dehne.  3.  Of Mr. Lorg-
na, who obtained much magnesia  by dissolving, evapo-
rating,  and calcining soda repeatedly (Journal de  Phy-
sique,  1787)!  Mr. Osburgh confirmed these various ex-
periments in 1785.
                     CHAPTER II.

     Concerning Ammoniac, or the Volatile  Alkali.

     OUR researches have not hitherto exhibited more than
      one  species of volatile alkali.   Its formation ap-
pears to be owing  to  putrefaction; and though  the dis-
tillation of  some schisti affords  it,  yet  this circumstance
may be attributed to  their origin,  which is  pretty gene-
rally ascribed to  vegetable  and  animal decomposition.
We find frequently enough,  in these substances, the print
of fishes, wiiich is in favour of this opinion.   Some plants 
VOLATILE  ALKALI.
139
 likewise afford volatile alkali;  for which reason they have
 been called  Animal  Plants.   But the volatile alkali is
 more .especially afforded by animal substances :  the distil-
 lation of all  their parts  affords it  in  considerable  abun-
 dance.   Horns are employed in preference,  because they
 are resolved  almost entirely into  oil  and volatile alkali
 The putrefaction of  all  animal substances produces vola-
 tile alkali; and in this case,  as well as in distillation, it is
 formed  by the combination of its two constituent parts:
 for the analysis very  often fails in exhibiting any  alkali
 ready formed,  in such parts as distillation or putrefaction
 would abundantly afford it from.
   Almost all the volatile alkali made use of in commerce
 or medicine, is afforded by the decomposition of sal am-
 moniac.  It  is even on account of this circumstance, that
 the chemists who have drawn up the New Nomenclature,
 have distinguished the volatile  alkali by the name of Am,
 moniac.
   To obtain ammoniac  in a state of considerable purity,
 equal parts of  sifted quick-lime and muriate of ammoniac,
 or common sal ammoniac in  powder, are mixed.   This
 mixture is then introduced into a  retort,  to  which  a re-
 ceiver and the  apparatus of Woulfe  have been  adapted.
 A quantity of pure water is to be put into the bottles, cor-
 respondent to the weight of the salt  employed;  and  the
junctures of  the  vessels  are  made good with the  usual
 lutes.   The  ammoniac is disengaged in the  state of gas,
 at the first impression of the fire.   It combines with  the
 water with heat; and when the wrater of the first botde is
 saturated, the  gas passes to diat of the second, and satu-
 rates it in its turn.*
   Volatile alkali is known by its very strong but not dis-
agreeable smell.  It  is  easiiy reducible into the state of
gas,  and preserves this form at the temperature of the at-
mosphere.   This gas may be  obtained by decomposing
the muriate of ammoniac by  quick-lime, and  receiving
 the product over mercury.

  * Put the sifted quick-lime and sal ammoniac into the oil flaskj
 Plate i, fig. 2. apply the heat of the lamp, and the ammoniacal  gas,
will pass through the glass tube, and be absorbed by the water in the
 bottle.—im.Ed. 
140
VOLATILE ALKALI.
  Alkaline gas kills animals, and corrodes the skin. The
irritation is such, that I have seen pimples arise  all over
the bodies of some birds exposed to its atmosphere.
•  This gas is improper for combustion;  but if a  taper
be  gently immersed  in it,  the flame is enlarged before it
goes out, and the gas suffers a decomposition.   Alkaline
gas is lighter than  atmospheric  air;  and  has  even been
mentioned, on account of its lightness, as a proper sub-
stance to fill balloons.  The count De Milly proposed to
place a brazier, or vessel containing  fire,  under the bal-
loon, to keep the gas in its  greatest state of expansibility.
   The experiments of  Dr.  Priestley,  who changed alka-
line gas into hydrogene gas by means of the electric spark;
those  of the chevalier Laudriani,  who,  by  passing  the
same gas through ignited  glass tubes, obtained a large
quantity of hydrogenous gas—occasioned a  suspicion of
the existence of hydrogene among the principles of alkaline
gas.   But the  experiments of Mr.   Berthollet  have re-
moved all doubts on  this subject; and all  observations ap-
pear to unite in authorizing us to consider this alkali  as a
compound of the nitrogenous and hydrogenous  gases.
    1. If the oxigenated muriatic acid be mixed  with very
pure ammoniac,  an effervescence takes place, with a  dis-
engagement of nitrogenous gas, a production  of water,
and a conversion of the oxigenated acid into the ordinary
muriatic acid.   In this beautiful experiment,  the wrater
which is produced is formed  by the  combination of the
hydrogene of the alkali and the oxigene of the acid;  and
tjie nitrogene gas being set at liberty, is dissipated.
    If the oxides of copper or gold be heated with ammq-
niacal gas, the product is wrater and nitrogenous gas, and
the metals are reduced.*
    I have observed that the oxides  of arsenic,  being di-
 gested with  ammoniac, are reduced,  and often form oc-
tahedral crystals of arsenic.  In this  case there is  a  dis-
engagement of nitrogene gas, and a formation of wrater.

   * Upon throwing the focus of a burning lens upon an  oxide of
 gold or copper, confined in ammoniacal  gas over mercury, the
 hydrogene of the ammoniac unites to the oxigene of the oxides, and
 forms  water, the azotic air of  the ammoniac is left behind.  The
 metals by being deprived of their oxigene,  are found in a revived
 state.—Am. Ed. 
VOLATILE ALKALI.
141
  It very often happens when metals,  such as  copper or
tin, are dissolved by means of the nitric acid diluted with
water, that an absorption of air takes place, instead of a
disengagement of nitrous gas, as might be expected; I
have seen several persons very much embarrassed in such
cases, and I have often been'so myself.  This phenome-
non takes place more especially when a very concentrated
acid is made use of,* and the copper is in fine  filings :
in this case ammoniac is  produced.  I  have  shewn  this
fact to my auditors long before  I was acquainted with the
theory of its formation.  That  which led  me  to^ suspect
its existence, was the blue colour which the solution takes
in this case.   This ammoniac is produced by thecombi-
nation of the hydrogene of the water with the nitrogene
gas of the nitric  acid; while  the  oxigene of the same
acid, and that of the water, oxided the metal, and  pre-
pared it for solution.  It is to a similar cause that we must
refer the experiment of Mr. John Michael Haussmann of
Colmar, who by passing nitrous  gas through a certain
quantity of precipitate of iron,  in the mercurial apparatus,
observed that this gas was speedily absorbed, and the co-
lour of the iron changed ; at the same time that vapour of
ammoniac was found in the  vessels.   It  is by a similar
theory we may account for die formation  of alkaline gas,
by the  mixture of hepatic gas and nitrous gas over  mer-
 cury, as  Mr. Kirwan observes.
   Mr.  Austin formed ammoniac;   but he observed that
 the combination of nitrogenous gas with the base of hydro-
•gene does not take place unless this last is in  a  state of
^great condensation.
   The formation of ammoniac by distillation and putre-
 faction, appears to me likewise to  indicate its constituent
 parts.  In fact, there is in both these operations  a disen-
 gagement of hydrogene and nitrogene gas, and their com-
 bination produces ammoniac.
   Mr.  Bcrthollet has proved, by the way of decomposi-
 tion, that one thousand parts of ammoniac, by weight, are
 composed of about eight hundred and  seven of nitrogene
 gas, and one hundred and ninety-three of hydrogene gas.

   * This  is a mistake.   Concentrated nitric acid has no actioo on
 copper.—Am. Ed. 
142        GENERAL PROPERTIES OF ACIDS.

—See the collection of the  Royal Academy, 1784, page
316.
  According to Dr. Austin, the nitrogene gas  is in pro-
portion to the hydrogene,  as one hundred and twenty-one
to thirty-two.*
saps
                     SECTION IX.


Ctmcerning the Combination of Oxigene with certain Bases forming
                        Acids.

   IT appears to be out of doubt, that the bodies which we
    are agreed to call Acids, are combinations of vital Air
with a certain elementary substance.  The analysis of al-
most all the Acids, whose component parts are known, es-
tablishes this truth in a positive  manner; and it is on ac-
count of this property that the denomination of Oxigenous
Gas has been given to vital air.
   Every substance which possesses the following  proper-
ties is called an Acid:
   A. The  word sour, which is usually employed to de-
note the impression or lively and sharp sensation produced
on the tongue by  certain bodies, may be regarded as syno-
nymous to the word acid.  The only difference which may
be established between them  is, that the  one denotes a
weak sensation, whereas the other comprehends all the
degrees of  force  from the least  perceptible taste to the
greatest degree of causticity.   We say, for example, that
verjuice, gooseberries, or  lemons, are sour; but we use
the word acid to  express the impression which the nitric,
sulphuric, or muriatic acids make upon the tongue.


   * It is asserted that ammoniac will give to new brandy, all the qua-
lities of that of the oldest date.  Five or six drops are to be poured
into each bottle of brandy, which is to be well shaken—Am. Ed. 
          6ENERAL PROPERTIES OF ACIDS.       143

  The causticity of acids appears to arise from tiieir strong
tendency to combination; and it is from this property that
the immortal Newton has defined them to be bodies which
attract and are attracted.
  It is likewise from this property tiiat certain chemists
have supposed acids to be pointed bodies.
  On account likewise of this decided tendency to combi-
nation which acids possess, it seldom happens that we find
them in a disengaged state.
  B. A second property of acids is that of changing cer-
tain blue vegetable colours into red, such as the colour of
turnsol,* &c. These two re-agents are commonly used to
ascertain the presence of acids.
  The tincture of turnsol  is prepared by lightly infusing
in water that substance which is known in common under
die name of  Turnsol or Litmus.   If the  water be too
highly charged with the colouring matter, the infusion has
a violet tinge, and must in  that case be diluted with water
Until it becomes blue.  The tincture  of turnsol, when ex-
posed to the sun, becomes  red, even in closed  vessels;
and some time afterwards the colouring part is disengag-
ed, and falls down in the form  of a  mucilaginous disco-'
loured substance.   Alcohol may be used instead of water
in the preparation of this tincture.
  It is generally supposed  that the turnsol fabricated in
Holland is nothing more than the  colouring matter ex-
tracted from the rags or cloths of turnsol of Grand-Ga-
largues, and precipitated upon a marly earth. These rags
are prepared by impregnating them with the juice of night-
shade  (morelle), and exposing them  to the vapour of
urine, which develops their blue colour.  The rags are
sent into Holland, which has given rise to the opinion that
they are used in the fabrication of turnsol; but subsequent
inquiries have taught me that these cloths are sent to the
dealers in cheese, who extract a colour by  infusion, and
wash their cheeses with it, to give them a red colour.  I
am convinced, by the analysis of turnsol, that the colour-
ing matter is of the same nature as that of archil (orseille):
and that this principle is fixed on a calcareous earth, and
a small quantity  of pot-ash.   In consequence of tiiis ana-
* And in general all blue vegetable colours
—.A-n. Ed. 
144
CENERAL PROPERTIES OF ACIDS.
 lysis,  I  have  endeavoured  to cause the liken parcllus of
 Auvergne to ferment with urine, lime, and alkali; and I
 obtained a paste similar to that of turnsol.   The addition
 of alkali appears to me to be necessary to prevent  the de-
 velopment of the red colour, wiiich when combined w ith
 the blue, forms the violet of the archil.
   When any  concentrated  acid is to be tried with sirup
 of violets, there are two particulars to be attended  to.  1.
 The sirup  of violets  is  often  green, because the petal of
 the violet contains a yellow part at its base,  which, when
 combined with the blue,  forms this green  colour: it is
 therefore essential to employ  only the blue of the petal in
 order to have a beautiful blue infusion.  2. Care must be-
 taken to dilute the sirup with a certain quantity of  water;
 because otherwise concentrated acids, such as the sulphu-
 ric, would burn it, and form a coal.
   The simple infusion  of violets may be used instead of
 the  sirup.*
   The colouring matter of indigo is  not  sensible  to the
 impression of acids.  The sulphuric acid dissolves it, with-
 out  altering the colour.
   C.  A third  character of acids is,  that they effervesce
 with alkalis; but this property is not general.   1. Because
 the carbonic acid, and almost all weak acids, cannot be
 distinguished by this property.  2.  Because  the  purest
 alkalis  combine with acids,  without motion or efferves-
 cence.
   Is there not one single acid in nature, of wiiich the others
 may be only modifications?
   Paracelsus admitted an universal  principle of acidity,
 which communicated taste and solubility to  all its com-
 pounds.
   Becher believed that this principle was composed of wa-
 ter and vitrifiable earth.   Stahl endeavoured to prove that
the sulphuric acid was the universal acid; and his opinion
was  adopted by  most chemists for a long time.
   Long after the time of  Stahl, Meyer maintained  that
the acid element was contained in fire.   This system,

  * The sirup of violets cannot be procured in the United  States.
An infusion of the blue cabbage is one of the most delicate tests, to
detect the presence of an acid or an alkali.—Am. Ed. 
CENERAL PROPERTIES OF ACIDS.
145
 which is founded on certain known facts, has had its sup.-
 porters.
   The chevalier Landriani imagined he had succeeded in
 reducing all the acids to the carbonic acid;  because, by
 treating them all with different substances, he obtained this
 last as the constant result of his analysis.  He was led into
 an error, for want of having sufficiently attended to the de-
 composition of the acids he made use of, and the combi-
 nation of their oxigene  with  the carbone of the bodies
 which entered into his experiments, and produced the car-
 bonic acid.
   Lastly, the strict analysis and synthesis of most of the
 known  acids, have proved to Mr, Lavoisier that oxigene
 is the base  of all of them; and that their differences and va-
 rieties arise only from the substance with wiiich this com-
 mon  principle is combined.
   Oxigene united with  metals forms oxides; and among
 these last  there are  some wiiich possess acid characters,
 and are classed amongst acid substances.
   Oxigene combined with inflammable  substances,  such
 as sulphur, carbone,  and oils, forms odier acids.
   The action of acids upon bodies in general cannot be
 understood but by founding our explanations upon thf»
 data which  wre have established respecting the nature of
 their constituent parts.
   The  adhesion of  oxigene to the base is more or less
 strong in the several acids,  and consequently their de-
 composition is  more or less easy;  as,  for example, in
 metallic solutions, wiiich do not take place excepting when
 the metal is in the state of an oxide.  The acid which will
 yield its oxigene with the greatest facility to oxide the metal,
 will have the  most  powerful action  upon  it.  Hence it
 happens, that the nitric and the  nitro-muriatic acids are
 those which dissolve  metals the most readily; and hence
 likewise it  happens, that the muriatic acid dissolves the
 oxides more easily than the metals, while the nitric acid
 acts contrary wise: hence also it arises that this last acts so
powerfully upon oils, Sec.
   It is  impossible to conceive  and explain the various
 phenomena presented to us by acids  in  their operations,
 if we have no idea of their constituent principles.  Stahl
 would not have believed in the formation of sulphur, if he
                            T 
146
GENERAL PROPERTIES AND
had understood the decomposition of the sulphuric acid
upon charcoal; and if we except the combinations of acids
with alkalis, and with certain earths, these substances are
either totally or partially decomposed in all the operations
made with them upon metals, vegetables, and animals, as
we shall find by observing the* several phenomena exhi-
bited  in these cases respectively.
   WTe shall at present treat only of some of the acids, and
shall direct our attention to the others in proportion as we
shall have occasion to treat of the various substances which
afford them; we shall attend in  preference to those which
are the best known, and which have the greatest influence
in the operations of nature, as well as in those of our labo-
ratories.
                     CHAPTER I.

            Concerning the Carbonic Acid

     THIS acid is almost always observed in the state of
      gas.  We find that the ancients were in some mea-
sure acquainted with it  Van Helmont called it Gas Sil-
vestre, the gas of must, or of the vintage.   Becher him-
self had a considerably accurate notion of  it, as appears
by the  following passage;  " Distinguitur autem  inter
" fermentationem apertam et clausam;  in aperta potus fer
" mentatus sanior est, sed fortior in clausa: causa est, quod
" evaporantia rarefacta corpuscula, imprimis magna aclhuc
" silvestrium spirituum copia, de quibus antea egimus, re-
" tineatur,  et  in  ipsum  potum  se precipitet, unde valde
"eum fortem reddit."
   Hoffmann attributed the virtue of most mineral waters
to an elastic spirit contained in them.
   Mr. Venel,  a  celebrated professor in the schools at
Montpellier, proved in 1750, that the waters of Seltzer
owed their virtue to a superabundant portion of air.
   In 1755,  Dr. Black of Edinburgh advanced that  lime-
stone contains much air of a different nature  from common 
HABITUDES OF CARBONIC  ACID.
147
air.  He affirmed that the disengagement of this air con-
verter! it into lime, and that by the restoration  of this air
calcareous stone was regenerated.  In the year 1746, Dr.
M'Bride supported  this doctrine with  new facts.   Mr.
Jacquin, professor of  Vienna,  resumed the same pursuit,
multiplied experiments on  the manner of extracting this
air, and added other proofs in confirmation that the ab-
sence of the air rendered alkalis caustic, and formed lime.
Dr. Priestley exhibited all  the perspicuity  and  precision
on this subject which might be expected from his  abili-
ties, and his skill in  making  experiments of  this  kind.
This substance was then known by  the name of Fixed
Air,  In 1772, Bergmann proved that it is an acid, which
he  called by the name of   Aerial  Acid.   Since the
time of this celebrated chemist, it has been distinguished
by the names of Mephitic Acid, Cretaceous acid,  &c.:
and as soon as it was  proved to consist of a combination of
oxigene and carbone, or pure  charcoal, the name of Car-
bonic acid was appropriated to it.
   The carbonic acid  is  found in three different states.  1.
In that of gas.   2.  In a state of mixture.   3. In a state
of combination..
   It is found in the state of gas at the Grotto del Cano,
near Naples; at the well of Perols, near  Montpeliier;
in that of Negrae in Vivarais  ; upon the surface of the
Lake Averno in Italy,  and on those of several springs ;
in various subterraneous places, such as tombs, cellars,
necessaries, he.  It is disengaged in this form by the de-
composition of vegetables  heaped together, by the fer-
mentation of wine or beer, by the putrefaction of animal
matters, &c.
  It exists in the state of simple  mixture in mineral wa-
ters, since in these it possesses all its acid, properties.
  It exists in a state  of combination in stone, common
magnesia,  alkalis, &c.
  Various processes are employed to collect it, according
to the state in which it is found.
   1. When the carbonic acid exists in  the state of gas,
it may be collected—1.  By filling a botde with water,
and emptying it into the atmosphere of this gas : the acid
takes the place of the water, and the bottle is  afterwards
corked to retain it.   2.  By exposing lime-water, caustip 
148
GENERAL PROPERTIES  AND
alkalis,  or even pure water, in its atmosphere ; the gase-
ous acid mixes or combines with tiiese substances; and
may be afterwards extracted by re-agents, which we shall
proceed to describe.
   II. When the carbonic acid exists in a  state of com-
bination, it may be extracted—1. By distillation with  a
strong heat.  2.  By the re-action of other acids,  such as
the sulphuric acid, which has the advantage of not being
volatile,  and consequently is  not altered by its mixture
with the carbonic acid which is disengaged.
   III. When the carbonic acid exists in the state of sim-
ple mixture, as in water, brisk wines, &c. it may be ob-
tained—1. By agitation of the liquid which contains  it;
as Mr. Venel practised, by  making use  of a botde to
which he adapted a moistened bladder.
   2.  By distillation of the same fluid.—These two first
methods are not accurate.
   The process  indicated by Mr.  Gioanetti, consists  in
precipitating the carbonic acid by  means  of lime  water,
weighing the precipitate,  and deducting  thirteen  thirty-
second parts for die proportion of carbonic acid; it having
been deduced from analysis, by this celebrated physician,
that thirty-two parts of carbonate of lime  contain  seven-
teen lime, two wrater, and thirteen acid.
   This substance is  an acid,  as is proved—1. Because
tincture of turnsol,  agitated  in  a botde filled with this
 gas,  becomes  red.   2.  Ammoniac, or  volatile  alkali,
poured  into a vessel  filled with  this gas, is  neutralized.
3. Water impregnated with this  gas, is strongly sub-acid.
 4. It neutralizes alkalis, and causes them to crystallize.^
   It remains at present to examine the properties of this
acid gas.
   A. It is unfit for respiration.  History informs us that
two slaves whom  Tiberius  caused to descend  into  the
Grotto del Cano, were immediately stifled;  and two cri-
minals that Peter de  Toledo caused to be shut in  there,
suffered the  same fate.  The abbe  Nollet, who had  the
courage to respire the vapour, perceived a suffocating sen-
 sation, and  a  slight degree of acidity, which produced
 cous;hing and sneezing.  Pilatre de Rosier, who presents
himself to our notice'on all occasions wherein clanger was
to be faced, caused himself  to be fastened by cords fixed 
HABITUDES  OF CARBONIC  ACID.       149
 under his arms,  and descended into  the  gaseous atmos
 phere of a back of beer in fermentation.   He had scarcely
 entered into the mephitis before  slight prickings  obliged
 him to shut his eyes) a violent suffocation prevented him
 from respiring, he felt a giddiness, accompanied with those
 noises which characterize the apoplexy : and when he was
Ndrawn  up,  his sight remained dim for several minutes;
 the blood had filled the jugulars;  his countenance had be-
 come purple;  and he neither heard nor  spoke but with
 great difficulty :  all these symptoms however disappeared
 by degrees.
    It is this gas which produces the many unhappy  acci-
 dents' at the opening of cellars,  in places  where wine, ci-
 der,  or beer are  suffered to ferment.   Birds plunged into
 the carbonic acid gas, suddenly perish.  The famous lake
 of Averno, where Virgil placed the entrance of hell, ex-
 hales so large a quantity of carbonic acid, that birds can-
 not fly over it with impunity.  When the waters of Bou-
 lidou of Perols are dry, such birds as attempt to quench
 their thirst in the clefts, are enveloped in the mephitic va-
 pour, and die.
    Frogs, plunged in an atmosphere of carbonic acid, live
 from forty  to sixty  minutes,  by suspending their  respira-
 tion.
    Insects are rendered torpid after a  certain time of re-
 maining in this air;  but they resume their liveliness the
 moment they are exposed to the free air.
    Bergmann pretended tiiat this acid suffocates by extin-
 guishing irritability : he founds his opinion upon  the cir-
 cumstance  of his having taken out the heart of an animal
 which  had  died in the carbonic  acid, before  it was cold,
 and  it exhibited no  sign of irritability.   The chevalier
 Landriani has  proceeded still further: for he affirms that
 this gas extinguishes irritability, even when applied to the
 skin ;  and  has asserted that, by tying a bladder full of this
 gas to  the neck of a fowl, in such a  manner tiiat the head
 only of the animal was  in  the  open  air, and the whole
 body enveloped  in the bladder,  the fowl immediately pe-
 rished.  The abb6 Fontana has repeated and varied this
 experiment on several animals, none  of which died.
    The count Morozzo published experiments  made  in
 the presence of Dr. Cigna;  the results of which appear 
150
GENERAL  PROPERTIES AND
to invalidate the consequences of the celebrated Berg-
mann :  but it is to be observed, that the chemist of Turin
caused his animals to die only in air vitiated by the death
of another animal; and that in this circumstance  the ni-
trogene gas predominates.—See the Journal de Physique,
torn. xxv. p. 112.                              '
.  B.  The carbonic acid is improper for vegetation.  Dr.
Priestley having kept the roots of several plants in  water
impregnated with the  carbonic  acid,  observed that they
all perished; and in those instances where plants are ob-
served to vegetate in water or in air  which contains this
gas, the quantity of gas is very small.
  Mr. Senebier has even observed,  that plants which are
suffered to grow in water slightly acidulated with this gas
emit a much larger quantity of oxigenous gas;  because,
in this case, the acid is decomposed, the carbonaceous
principle combines, and is fixed in the vegetable,  while
the oxigene is tiirown off.*
   I have observed that those fungi wiiich are formed in
subterraneous places,  are almost totally resolved into car-
Ixinic acid;  but if these vegetables be gradually exposed
to the action of light,  the proportion of acid diminishes;
while that of the coaly principle augments, and the vege-
table becomes  coloured.  I have pursued these  experi-
ments with  the greatest care in a coal mine.
  C.  The carbonic acid is easily dissolved in water. Wa-
ter impregnated with this acid possesses very valuable me-
dicinal qualities; and several apparatus have been suc-
cessively invented to facilitate this  mixture.   The  appa-
ratus of Nooth, improved by Parker and Magellan, is one
of the most ingenious.  On this subject  the Encyclope-
dic Mediodique may be consulted, article Acide  Mephi-
tique.
  The natural acidulous mineral waters do not differ from
these, excepting in consequence of their  holding  other
principles in solution ; and they may be perfectly imitated

  * The water which Dr. Priestley used, was too strongly impreg-
nated with carbonic acid.  Water containing a small portion of the
air, is favourable to vegetation.  It acts as a gentle stimulant to the
plant, and is decomposed by it; whereas too large a quantity of
the fixed air, brings on indirect debility in the vegetable, and de-
stroys it.—Am. Ed. 
          HABITUDES  OF CARBONIC  ACID.       151

when their analysis is well known.   It is absurd to think
that art is incapable of imitating nature in the composi-
tion  of mineral  waters.   It  must be admitted that the
processes of nature are absolutely unknown to  us,  in all
the operations which relate to life ; and we cannot  flatter
ourselves with the hope of imitating her in these circum-
stances.   But when the question relates  to an operation
purely mechanical,  or  consisting of the  solution of cer-
tain known principles in wrater,  we can and ought to per-
form it even still better, as we  have  the  power of vary,
ing the doses, and proportioning the  efficacy of any ar-
tificial mineral water to the purposes to  which it  is in-
tended to be applied.
   D. The carbonic acid gas is heavier than common air.
The proportion between these two airs in w eight, accord-
ing to Mr. Kirwan, is 45,69 to 68,74.   The proportion
according to the experiments of Mr. Lavoisier, is 48,81
to 69,50.
   This considerable weight causes it to occupy the lowest
situations; and even gives it the property of being poured
out from one  vessel to another, so as to  displace the at-
mospheric air.  This truly curious phenomenon was ob-
served by Mr. De Sauvages, as may be seen in his Dis-
sertation upon air, which was crowned in Marseilles  in
1750.
   It appears to be proved, by sufficient experiments, that
the carbonic acid is a combination  of carbone, or pure
charcoal and oxigene.   1. The oxides of mercury, when
distilled,  are reducible without addition,  and afford only
dxigenous gas;  but if a  small quantity of charcoal be
mixed with the oxide, the  product which  comes over
consists of carbonic gas only, and the weight of the char-
coal is diminished.
   2. If well-made charcoal be ignited, and plunged into
a"vessel filled  widi oxigenous gas, and die vessel  be in-
stantly closed, the charcoal burns rapidly, and at last goes
out: the  product  in this experiment is carbonic acid,
which may be separated by the known processes;  the re-
mainder is a small quantity of oxigenous gas, which may
be converted into carbonic acid by the same treatment.*

   * Carbonic acid may be decomposed, by boiling  phosphorus in a
solution of the carbonate of potash i or by exposing small pieces of 
152
CARBONATE OF POTASH.
   In these experiments I see nothing but charcoal and ox-
igenous gas; and the consequence deduced is simple and
natural.
   The proportion of  charcoal  is  to that of  oxigene as
12,0288 to 56,687.
   When the carbonic acid, in some cases, is obtained by
burning hydrogenous  gas, it arises from carbone held in
solution in this gas.   The carbone may even be dissolved
in hydrogenous gas, by exposing it to  the  focus of the
burning mirror in the mercurial apparatus, under a  glass
vessel filled with this gas.
   The  hydrogenous gas which is extracted from a  mix-
ture I of sulphuric acid and  iron,  holds  more  or less of
charcoal in solution; because iron itself contains this sub-
stance in a greater or  less quantity,  as is ascertained by
the fine experiments of Messrs. Berthollet, Monge, and
Vander Monde.*
   The alkalis, such as we usually meet with them, con-
tain carbonic  acid;  and it is this acid which modifies
them, and diminishes their energy, at the same time that
it communicates to them the property of effervescing. We
may therefore consider alkalis  as carbonates with excess
of alkali;  and it is easy to saturate this superabundant al-
kali, and to form true crystallizable neutral salts.


                      ARTICLE I.

                  Carbonate of Potash.

   The carbonate of pot-ash was formerly distinguished by
die name of Cretaceous Tartar.   The  method of causing

phosphorus and limestone in powder to  a red heat, in  a glass tube,
which should be coated with a mixture of dung and clay. The oxi-
gene of the carbonic acid, of the carbonates of pot-ash or lime, will
unite with the phosphorus and form phosphoric acid, which will join
to the pot-ash and lime, making phosphates of lime  and pot-ash.
The carbone of the carbonic acid will be deposited among these
phosphates.—Am. Ed.
   * An ounce of bar iron does not contain more than half a grain of
charcoal, whereas the same quantity of cast iron contains from twelve
to twenty grains.—dm, Ed. 
                CARBONATE OF SODA.             153
                                                 l
oil of tartar to crystallise, has long been known. Bonhius
and Montet have successively shewn these processes: but
the simplest consists in exposing an alkaline solution in an
atmosphere of the acid gas which is disengaged in the vi-
nous  fermentation;  the  alkali becomes  saturated,  and
forms  tetrahedral  prismatic crystals terminated by very
short four-sided pyramids.
  I have several times obtained those crystals in the form
of quadrangular prisms,  with their extremities  cut off
slantwise.
  This neutral salt no longer  possesses the urinous taste
of the alkali,  but exhibits the  penetrating taste of  neutral
salts, and may be employed in medicine with the greatest
success.  I have been a witness to its being taken in the
dose of one dram (gross) without the least inconvenience.
  This salt possesses an advantage beyond the salt of tar-
tar, in being  less caustic, and always of the same virtue.*
  It  contains, according  to  the analysis of Bergmann,
twenty  parts  acid, forty-eight alkali, and thirty-two water,
in the quintal.
  It does not attract the humidity of the air.   I have pre-
served some  of it for several  years in a capsule, without
any appearance of alteration.
  The  carbonate of potash is decomposed by silex in a
sufficient heat,  which occasions a considerable boiling or
ebullition.  The residue is glass, in which the alkali is in
the caustic state.   Lime decomposes the carbonate, by
uniting to the acid; and acids produce the same effect, by
combining with the alkaline bases.


                      ARTICLE II.

                  Carbonate of Soda.

  The  denominations of Aerated Mineral Alkali, Creta-
ceous Soda,  &c. have been successively given to this kind
of carbonate.
  The  mineral alkali, in its natural state, contains a greater
quantity of carbonic acid than the vegetable;  and nothing

  * It is  preferable to the common alkali in making the effervescing
or anti-emetic draught of Riverius.—Am, Ed.
                          U 
154
CARBONATE OF AMMONIAC.
more is necessary than to dissolve it, and  duly evaporate
the water, in order to obtain it in crystals.
   These crystals are usually rhomboidal octahedrons; and
sometimes have the form  of rhomboidal laminae, applied
obliquely one upon the other, so that they resemble tiles.
   This carbonate effloresces in the air.
   One hundred parts contain  sixteen parts acid, twenty
alkali, and sixty-four w ater.
   The affinity of its basis with silex is stronger than that
of the carbonate of potash; in consequence of which, the
vitrification it produces is more quick and easy.
   Lime and the acids decompose it, with the same pheno-
mena wliich we have observed at the article Carbonate of
Potash.
                     ARTICLE  III.

                Carbonate of Ammoniac.

   This salt has been generally  known by  the name  of
Concrete Volatile Alkali.   It has  likewise been  distin-
guished by that of Cretaceous Volatile Alkali, &c.
   It may be obtained by  distillation from many animal
substances.   Tobacco affords, likewise,  a large propor-
tion;  but almost the whole of that  which is employed in
the arts, and in medicine, is formed by the direct combi-
nation of the carbonic acid and ammoniac, or volatile al-
kali.   This combination may be affected—1. By passing
the carbonic  acid through ammoniac,  or the pure volatile
alkali in  solution.  2. By exposing ammoniac in  an at-
mosphere of carbonic acid gas.  3.  By decomposing the
muriate of ammoniac by the neutral salts which contain
this acid, such as the carbonate of lime or common chalk.
For this purpose, white chalk is taken,  and very accurately
dried;  and then mixed with equal parts of muriate of am-
moniac, or common sal ammoniac in  fine powder.   This
mixture is put into  a retort, and distilled; the ammoniac
and the carbonic acid being disengaged from their  bases,
and reduced into vapours, combine together, and are de-
posited on the sides of the  receiver, where  they form a
stratum more or less thick. 
OXIDE OF CARBON.
15.5
   The crystallization of this carbonate appeared to me to
be that of a four-sided prism,  terminated by a dihedral
summit.
   The carbonate has less smell than the ammoniac;  it is
very soluble in water. Cold water dissolves its own weight
of this salt, at the temperature  of sixty degrees of Fahren-
heit.
   One hundred grains of this  salt contain forty-five parts
acid,  forty-three  alkali, and twelve water,  according to
Bergmann.
   Most  acids  decompose  it,  and displace  the  carbonic
acid.*
        * Gaseous Oxide of Carbone, or Carbonic Oxide Gas.

  This air was discovered by Dr. Priestley in the year 1790, by ex-
posing the scales which the blacksmiths strike off from red-hot iron,
called by him finery cinder, to a red heat, mixed with the powder of
charcoal.  The experiment is related in the first volume of the Doc-
tor's,treafise on different kinds of air.
  In some observations on the theory of  chemistry, published at the
end of the third volume, he refers to this experiment,  and insists that
it cannot be explained by the principles of the antiphlogistic system.
  After the Doctor's  arrival in America, he addressed a small pam-
phlet, entitled " Considerations on the Doctrine of Phlogiston and the
Decomposition of Water," to Messrs. Berthollet, De la Place, Monge,
Morveau, Fourcroy and Hassenfratz,the  most eminent of the French
chemists, and again made an attempt to call their attention to this ex-
periment.
  According to these gentlemen, says Dr. Priestley, inflammable air
is nothing more than one of the component  parts of water;  but if
this is a fact, " it never could be produced but in circumstances, in
which either water itself, or  something into which water is known to
enter, is present.   But in my experiments on heating finery cinder,
together with charcoal, inflammable air is produced,  though accord-
ing to the  new theory,  no  water is concerned.  According to this
theory, finery cinder, called the oxide of iron, consists of nothing be-
sides iron and oxigene ; and the charcoal mace with the  greatest de-
gree of heat that can be applied, is equally free from water ; and yet,
when these two substances are mixed together, they yield inflamma-
ble air in the greatest abundance."
  Two arfswers were immediately written to this performance of Dr.
Priestley, one by Monsieur Adet, then Minister Plenipotentiary from
the Republic of France to the United States of America, and the other
by Dr. John Maclean, Professor of Chemistry in Princeton College,
New-Jersey.   Mr. Adet supposed, that  the  inflammable  air  came
from  the charcoal, to which it had a very strong affinity, and whirh 
GASEOUS OXIDE OF CARBONE.
CHAPTER II.
             Concerning the Sulphuric Acid.

    SULPHUR, like every other combustible substance,
     cannot be burnt but by virtue of the oxigenous gas
which combines with it.

it was very difficult to separate from it. This was also the opinion of
Berthollet.  Dr. Maclean declared that the experiment was of no va-
lue, but attempted to account for  it by the presence of moisture in
the retort or charcoal which was made use of.
  Before tnest: gentlemen replied to Dr. 1-riestley, I  repeated this fa-
mous experiment, in the following manner:
  An ounce of the scales of iron, and the same quantity of charcoal,
were reduced to a very fine powder, and exposed separately in cover-
ed cruciules, in  an air furnace, well supplied with fuel for five hours.
They were then taken out of the  fire, and mixed while red hot, in a
red hot iron mortar, were triturated with a red hot pestle, formed of
an iron ramrod, were poured upon a  red hot sheet of iron, and in-
stantly putinto a red hot L.un-barrel, which was fixed in one of Lewis's
black lead furnaces, and which  was connected with a pneumatic ap-
paratus.   One hundred and forty-two ounce measures of inflammable
air, mixed with carbonic acid gas, were obtained in this experiment.
The iron was revived.
  Having discovered some time after this, that the calces  of zinc,
lead, tin, bismuth, copper and  manganese, exposed a considerable
time to a red heat, and then mixed with charcoal that had ceased to
yield air, would afford large quantities of carbonic acid gas and inflam-
mable air, and sometimes inflammable air without any mixture of
fixed air, I  pronounced that the result of these experiments could
not be accounted for in a satisfactory manner, by the antiphlogistic
system of chemistry.
   A copy of the objections, which may be seen in the Medical Repo-
sitory of New-York, vol. iv, p. 112, were sent to the National Insti-
tute of France, and they were immediately republished in one of the
volumes of the  Annals of Chemistry.
   The objections were conceived as valid, until Mr. Cruikshank* of
Woolwich, Great-Britain, having repeated these experiments, and
found them accurate, made a successful analysis of the air obtained by
exposing metallic calces and coal to heat, and proved that it was not
carbonated hydrogene gas, or coal dissolved in inflammable air, as was
generally conceived, but a combination of carbone and oxigene, and
which has lately received the name of the gaseous oxide of carbone.
   It differs from the carbonic acid, in containing a smaller proportion
of oxigene, and these two gases, may be converted into each other at
pleasure.
* Nicholson's Chemical Journal, April, 1805. 
OR  CARBONIC OXIDE  GAS.
157
   The most usual phenomena which accompany this com-
bustion are, a blue flame, a whitish and suffocating  va-
pour, and a strong,  penetrating, and disagreeable smell.
   The results of this combination  vary according to  the
proportion in which these two  principles enter into  this
same combination.
   The sulphureous or the sulphuric acid may be at plea-
sure obtained from sublimed sulphur,  or from  crude  sul-
phur, accordingly as a greater or less quantity of oxigene
is combined with the sulphur,  by means of combustion.

   This air may be obtained,
   First. By exposing most metallic calces and charcoal, to a red heat.
   Secondly. By exposing to a high degree of heat, the carbonates of
lime and barytes, mixed with the filings of zinc or iron.
   Thirdly. By exposing moistened charcoal to a red heat, according
to Morveau, Berthollet, Fourcroy, Thenart, Desormes, and Clement,
^s quoted by Thomson.
   Fourthly. By mixing charcoal and the earthy carbonates, and sub-
mitting them to heat.
   Fifthly.  By passing carbonic acid repeatedly over red hot coal, or
transmitting it over red hot iron wire.  The iron wire will abstract a
portion  of oxigene from the carbonic acid,  and convert it into the oxide
of carbon.
   I mixed 40 grs. of dry  coal, with half an ounce of colcothar of vi-
triol, and put the mixture into a gun-barrel.  Half an ounce of the
oxide of copper, prepared by exposing the sulphate of copper  to an
intense  heat, was placed over the charcoal and calx of iron.  Upon
exposing the gun-barrel to a high degree of heat, one hundred ounce
measures of carbonic acid gas were procured, without any mixture of
the oxide of carbone.
   In this case, the carbone united with the oxigene of the colcothar
of vitriol, and formed carbonic acid gas and oxide of carbone ; but as
this oxide of carbone passed over the calx of copper, it seized another
portion of oxigene, and was converted into carbonic acid gas.
   The  gaseous oxide of carbone is lighter than atmospheric air, or
carbonated hydrogene gas.  It is fatal to animal life, and improper for
combustion.  When breathed for a few minutes, it produces giddiness
and fainting.  Neither heat, light, nor electricity have any effect up-
on it.   It  dissolves phosphorus. It  is not  affected by the alkalis.
 Exploded in the eudiometer of Volta with oxigene air, it is convert-
 ed into  the carbonic acid.
   If four parts of oxigenated muriatic  acid gas is mixed with one
 part of carbonic oxide gas, the oxigene of the oxymuriatic gas, will
 unite to the oxide of carbone, and form carbonic acid gas, and a sub-
 stance similar to wax will make its appearance.
   Oxide of carbone, mixed with sulphurated hydrogen gas, and pass-
ed through a red hot tube, will deposite sulphur, and sulphurated hy-
drogen gas, mixed with carbonic oxide gas, will remain.—Am.  Ed- 
158       PRODUCTION  OF THE  SULPHURIC

  When the current of air which maintains the combus-
tion  is rapid,  the sulphur is carried, and deposited with-
out any apparent alteration, into the internal  part  of the
leaden chambers in which the oil of vitriol is made.   If
the current of air be rendered more  moderate, the com-
bination is somewhat more accurate ; the sulphur is partly
changed, and  is deposited in a pellicle upon the surface
of the water.  This pellicle is flexible  like a skin, and
may be handled and turned over in the same manner.   If
the current be still less rapid, and the air  be  suffered to
have a sufficient time to form an accurate combination
with the sulphur, the result is  sulphureous acid;  which
acid preserves its gaseous form at the temperature of the
atmosphere, and may become liquid like water by the ap-
plication of cold,  according  to the  fine experiments  of
Mr.  Monge.  If the combustion be still slower, and the
air be suffered to digest upon the sulphur  a longer time,
and with greater accuracy, the result is sulphuric acid :
this last combination may be facilitated by the mixture  of
saltpetre, because this substance  furnishes oxigene very
abundantly.
  Numerous experiments which I have made in my ma-
nufactory, to economize  the saltpetre employed in the fa-
brication of oil of vitriol, have several times exhibited the
results here mentioned.           ^
  All the processes which are capable of being adapted
for extracting the sulphuric acid, are reducible to—1. The
extraction of it from substances which contain it.   2.  Its
direct formation by the combination of sulphur and oxi-
gene.
   In the first case, the sulphures, or vitriolic salts of iron,
copper, or zinc,  and even those whose bases are clay and
lime, according to Newman and Margraff, may  be  ex-
posed to distillation.  But these expensive processes are
not very easy to be carried into execution ; and accord-
ingly they have been abandoned, to make  room for others
of greater simplicity.
   In the second case,  the oxigene may be presented  to
the sulphur in two forms;  either in the state of gas, or in
the concrete state.
   1. The combustion of sulphur by  oxigenous  gas, is
performed  in large chambers lined with lead.   The com- 
ACID,  BY  COMBUSTION.
159
 bustion is facilitated by mixing  about one-eighth of the
 nitrate of pot-ash with  the  sulphur.   The  acid  vapours
 which fill the chamber are precipitated against its sides,
 and the condensation is facilitated by a stratum  of water
 disposed on the bottom of the chamber.   In some manu-
 factories in Holland,  this combustion is  performed in
 large glass balloons with large mouths, and the  vapours
 are precipitated upon water placed at the bottom.
   In both cases when die water is sufficiendy  impreg-
 nated with acid, it is concentrated in leaden boilers,  and
 rectified in glass retorts, to render it white, and  to  con-
 centrate it sufficiently for the purposes  of trade.  The
 acid,  when of  a due strength, indicates sixty-six  degrees,
 according to the aerometer of Mr. Baume; and  when  it
 has not been carried to this  degree,  it is  unfit for most
 of the uses for which it is intended.   It cannot,  for  ex-
 ample,  be employed in dissolving indigo;  for the small
 quantity of nitric acid which it contains,  unites  with the
 blue  of the indigo, and forms a green  colour.   I have as-
 certained this phenomenon by very accurate experiments;
 and I have been a witness to the failing  of colours,  and
 the loss of stuffs, in consequence of the imperfection of
 the acid.
   2.  When the oxigene in the concrete state is presented
 to the sulphur,  it is then in combination  with other  bo-
 dies,  which it  abandons to unite  with this  last.  This
 happens when  the nitric  acid is distilled from  sulphur.
 Forty-eight ounces of this acid, at thirty-six degrees, dis-
 tilled from two ounces of  sulphur,. afforded near four
 ounces  of good sulphuric acid.   This fact was known to
 Matte Lafaveur : but I pointed out all the phenomena and
 circumstances of the operation in 1781.
   Sulphur may likewise be  converted  into sulphuric acid
 by means of the oxigenated muriatic acid.-----Encyclo-
 pedic Methodique, torn. i. p. 370.
   The  sulphuric acid which is found disengaged  in some
places in Italy,  appeal's likewise to  arise from the com-
bustion of sulphur.   Baldassari  has observed it  in this
state in a hollow grotto, in die midst of a mass of incrus-
 tations deposited by the baths of Saint Philip, in Tusca-
ny.  He asserts that a  sulphureous vapour  continually
arises in this grotto.   He likewise found sulphureous and 
 160 NATURAL  AND CONGEALED SULPHURIC  ACID.

 vitriolic effervescences at St. Albino,  near  mount Pulci-
 ano, and at the lakes of Travale,  where he observed the
 branches of a tree covered with  concretions  of sulphur
 and the oil of vitriol.—Journal de Physique, t.  vii. p. 395.
   O. Vandelli relates that, in the environs  of  Sienna and
 Viterbo, sulphuric acid is sometimes  found dissolved  in
 water.   Mr. (the commander) De Dolomieu affirms that
 he found it pure  and crystallized  in  a grotto of mount
 Etna, from which sulphur was formerly obtained.
   According to a first experiment  of Mr. Berthollet, six-
 ty-nine  parts of sulphur with thirty-one parts  of oxigene
 formed one hundred parts of sulphuric acid; and, accord-
 ing to a second experiment, seventy-two of sulphur and
 twenty-eight of oxigene formed one hundred parts of dry
 acid.
   The various degrees of concentration of the sulphuric
 acid have caused it to be distinguished by different names,
 under which it is known in commerce.  Hence the deno-
 minations of Spirit of Vitriol,  Oil of Vitriol, and Gla-
 cial Oil of Vitriol, to express its degrees of  concentration.
   The sulphuric acid is capable of passing to the concrete
 state by the impression  of intense  cold.*   Kunckel and
 Bohn have spoken of it; and  Boerhaave says expressly
 " Oleum vitrioli,  summa arte purissimum,  summo frigo-
 re hibemo in glebas solidescit perspicuas; sed, statim ac
 acuties frigoris retunditor, liquescit et difnuit"—We are
 indebted to the Duke D'Ayen for some very valuable ex-
 periments upon the congelation of this acid ; and Mr. De
 Morveau repeated them with equal success in  1782, and
 proved that this congelation may be effected  at a degree
 of cold considerably less than what had been mentioned!.
   I have already  several times obtained beautiful  crystals
 of sulphuric acid in flattened  hexahedral prisms,  termi-
nated by an hexahedral pyramid; and my experiments
have enabled me to conclude—1. That the very concen-
trated acid crystallizes more  difficultly  than that  whose
density lies between sixty-three and sixty-five.  2. That
the proper degree of cold is from 1 to  3 degrees below

  * See also the experiments of Mr. Kier, and the  late experiments
of Mr. Cavendish on the congelation of acids, in the Philosophical
 Transactions.
  t This congelation is a phenomenon long  since known. 
CHARACTERS  OF  SULPHURIC  ACID.      161
 0 of Reaumur.  The detail of my experiments may be
 seen in the volume of the Academy of  Sciences of Paris
 for the year 1784.
   The characters of the sulprruric acid are the following:
   1. It is unctuous and fat to the  touch,  which  has oc-
casioned it to obtain the  very improper name  of Oil  of
Vitriol.
   2. It weighs one  ounce and seven gross  in a bottle con-
taining one ounce of distilled water.
   3. It produces heat, when mixed with water, to such
a degree as to exceed that of boiling water.   If one end
of a tube of  glass be closed, and  water poured  into it,
and the closed end  of this tube  be  plunged into water,
the water in the tube may be  made  to  boil  by pouring
sulphuric acid into  the external water which surrounds
the tube.         /
   4. It seizes  with great  avidity all  inflammable sub-
stances ;  and it is blackened and decomposed by this com-
bination.
   Stahl supposed the sulphuric acid to be the  universal
acid.   He  founded this opinion more especially upon the
circumstance, that cloths soaked in a solution  of alkali,
and exposed to the  air attracted an acid which combined
with the alkali; and formed a neutral  salt,  by him sup-
posed to be of the nature of sulphate of potash,  or vitri-
olated  tartar.   Subsequent  and more  accurate  experi-
ments have shewn that this aerial acid was the carbonic;
and the present state of our knowledge is such as permits
us still less than ever to believe in the existence of an uni-
versal acid.
                    ARTICLE I,

                 Sulphate of Potash.

  The sulphate of potash is described indifferently under
the names of Arcanum Duplicatum, Sal de Duobus, Vi-
triolated Tartar, Vitriol of Potash,  &c.
  This salt crystallizes in hexahedral prisms, terminating
in hexahedral pyramids, with triangular faces.
                         2\. 
162
SULPHATE  OF POTASH.
  It has a  lively and  penetrating taste, and  melts difti-
cultly in the mouth.
  It decrepitates on hot coals,  becomes red-hot before it
fuses, and is volatilized without decomposition.
  It is soluble in sixteen parts of cold water, at the tem-
perature of 60  degrees  of Fahrenheit: and  boiling wa-
ter dissolves one-fifth of its weight.
  100 grains  contain 30,21 acid,  64.61 alkali, and 5.18
water.  Most of the sulphate of potash used in medicine
is formed by  the direct combination of the sulphuric acid
and  potash, or the vegetable alkali:  but that  which is
met with in commerce is produced in the distillation of
aqua fortis, by the sulphuric acid;* this has the form of
beautiful crystals,  and is sold in the  Comtat  Venaisin at
forty or fifty livres the quintal.   The analysis of tobacco
has likewise afforded me this sulphate.
   Mr.  Baume  proved to the Academy, in 1760, that the
nitric acid, assisted by heat, is  capable of decomposing
the  sulphate  of potash.   Mr. Cornette afterwards shewed
that the muriatic acid possesses the  same virtue;  and  I
shewed, in 1780, that this acid may be displaced by the
nitric acid,  without die  assistance  of heat; though the
 suJphuric  acid resumes  its place when the solution  is con-
 centrated  by  heat.
                     ARTICLE II.

                   Sulphate of Soda.

  This combination  of the  sulphuric  acid and  soda is
still known under the names of Glauber's  Salt,  Sal Ad-
mirabile,  Vitriol of Soda, &c.  This salt  crystallizes in
rectangular octahedrons, of a prismatic or cuneiform fi-
gure, of which the two pyramids are truncated near their
basis.
  It has a very bitter taste, and  easily dissolves in the
mouth.

  * When the sulphuric acid is added to nitre, to make the nitric
acid, it unites with the  potash of the nitre,  and  forms vitriolated
tartar, while the acid is disengaged from its-alkaline base.—Am. Ed. 
SULPHATE OF  SODA.              163
   it swells up  upon heated  coals, and boils,  in conse-
quence of the dissipation  of  its water of crystallization.
After  this water has been dispersed,  there remains only a
white  powder,  difficult of fusion, which  is volatilized
without decomposition by a strong heat.
   By exposure  to the air,  it  effloresces, loses its transpa-
rency,  and is reduced to a fine powder.
   Three parts  of  water,  at  60  degrees of  Fahrenheit's
thermometer,  dissolved one part of this salt; but boiling
water dissolves its own weight.
   100 grains of sulphate of soda contain 14 acid, 22 al-
kali and 64 water.
   It is formed by the direct combination of die two prin-
ciples wliich contain it; but the  tamarix gallica,  which
grows on the sea coasts, contains so large a quantity, that
it may  be extracted to advantage.   Nothing  more is  ne-
cessary for this purpose, than to burn the plant,  and lixi-
viate the ashes.  That salt  which is sokl in the south of
France,  in fine  crystals, is prepared  in diis  manner.  It
is very pure, and the price does not exceed thirty or thir-
ty-five livres the quintal.   This sulphate is likewise form-
ed in our laboratories when we decompose the muriate of
soda,  or common salt, by the sulphuric acid.*
   Potash dissolved by heat in a solution of sulphate of
soda,  precipitates the soda, and takes its place.f

   * Glauber's salt may be made by decomposing the sulphate of am-
moniac  by common salt.  The sulphuric acid of the sulphate of am-
moniac  will  unite to the soda of the common salt, and form  Glau-
ber's salt, while the muriatic  acid of the common salt will join to
the ammoniac of the sulphate of ammoniac, and form sal ammoniac.
   The sulphate of ammoniac may be made by the direct combina-
tion of the sulphuric acid and the ammoniac distilled from bones ;
or by digesting this ammoniac, which contains a considerable  quan-
tity of carbonic acid, or plaster  of Paris, which is a sulphate of
lime.   By a double elective attraction,  carbonate of ljme and sul-
phate of ammoniac will be formed.  The  editor of this work pub-
lished this process, in the Columbian Magazine, in the year 1791,
and it is now carried into effect in France and England.
   Glauber's salt is manufactured in immense quantities, from sea
water, in the eastern parts of  Massachusetts.  It is said that twenty
tons a year are made   Medical Repository, vol. ii. Hexade second.
p. 449.—Am. Ed,
   t One of the various methods of obtaining soda from sulphate of
soda,  is by adding potash, whereby the sulphuric acid is transferred
to the vegetable alkali, and the soda is  left  uncombined.  This ge-
nerally  answers in an economical point of view,  as the price «f 
AMMONIAC.
                        ARTICLE III.

                   Sulphate of Ammoniac.

   The  sulphate of ammoniac, commonly known by the
name of Glauber's Secret Ammoniacal Salt,  is very bit-
ter.
   It crystallizes in long flattened  prisms  with six sides,
terminated by six-sided pyramids.
   It cannot be obtained in  well-formed crystals but  by
insensible evaporation.
   It slightly attracts the humidity of the air.

potash is much lower than that of soda; and besides in the cry-
stallizedi state in which the carbonate of soda  is prepared for sale,
water of crystallization  forms a very large  proportion of its com-
position.
   Mr. Accum describes this process of transferring the alkali to
be the following,  when prepared in the large way :
   Five  hundred parts  of sulphate of soda are put in|o an iron boil-
er with a  sufficient  quantity of water,  and in another iron boiler
by the  side  of  the  former are  dissolved  five hundred  pounds  of
American potash, in about thirty pails full  of water.  When both
solutions  are boiling  hot,  the  potash  solution is  laded into  the
boiler of  sulphate of soda,  the mixture strongly agitated, and brisk-
ly heated :  when  gently boiling, the whole liquor  is laded into a
cistern  of wood, lined with sheet lead  half an inch thick, and also
containing slips of sheet lead two  or three inches  wide, suspend-
ed in the  fluid, at intervals of about four inches from each other.
In about  three  days, when the whole is  quite cold, the uncrystal-
lized liquor  is let off, and a large mass of salt is found adhering to
the slips of lead, and settled to the bottom of the cistern.  This salt
is chiefly  a mixture of sulphate  of potash  and carbonate of soda.
It is then washed in cold water, transferred into the boiler, and again
dissolved in clear water, and evaporated briskly, till a strong pellicle
appears on the surface.  The liquor is then cooled till the hand can
be borne in it, and the heat kept at that point as long as pellicles
form on the  surface, and drop down to the  bottom.   These  pelli-
cles are the sulphate of potash,  separated by evaporation of the li-
quid, on account of its more difficult solubility in water than  the
soda.
   The remaining liquid,  which now contains little else than carbo-
nate of soda, is laded out and suffered to crystallize, and then dried
for sale.   By this process about  one hundred and thirty-six pounds
of carbonate of soda is prepared from one hundred pounds of  sul-
phate of soda, with the requisite proportion of potash.   The  smaller
grained crystals are the purest;  the larger  masses of carbonate of
soda  still  contain a considerable quantity of sulphate of potash.
164
SULPHATE  OF 
SULPHATE OF  AMMONIAC.
165
  It liquefies by a gentle heat, and rises over a moderate
fire.
  Two parts of cold water dissolve one of this salt;  and
boiling water dissolves its own weight, according to Four-
croy.  The fixed alkalis,  barytes, and lime, disengage
the ammoniac from it.
  The nitric and muriatic  acids disengage the  sulphuric
acid.
  The different substances of wliich we have treated are
of considerable use in the arts and medicine.
  The sulphureous acid is employed in whitening  silk,
and giving it a degree of  lustre.  Stahl had even com-
bined it with alkali,  and formed the salt  so  well known
under  the name of Stahl's  Sulphureous Salt.   This com-
bination passes quickly to  the state of  sulphate, if it be
left exposed to thev air; as it speedily absorbs the oxigene
which is wanting for that purpose.
   The principal use  of the sulphuric acid is in dying, in
which art it serves to dissolve  indigo, and carry  it  in a
state of extreme division upon the stuffs to be dyed;  it is
Ukewisc used by the manufacturers of Indiens, or silk and
stuff mixtures, to carry off the preparation of these goods,
wherein lime  is used.   The chemist makes great use of
this acid in his analyses; and to separate other acids from
their combination;  suc.h as the carbonic, the nitric,  and
the muriatic acids.
   The sulphate of potash is known in medicine as an al-
terative, and is used in cases of lacteous coagulations. It
is given  m the dose of a  few grains, and is even purga-
tive  in a greater dose.
   The sulphate of soda is an effectual purgative in the
dose of from four to eight gross, or drams.   For this  pur-
pose it is dissolved in a pint of water. 
4CID  OF NITRE, OR  NITRIC  ACIB.
                     CHAPTER III.

              Concerning the Nitric Acid.*

      THE nitric  acid,  called  Aqua  Fortis, when diluted
       with water, in commerce, is  lighter than the sul-
phuric.  It usually has a yellow colour, a strong and dis-
agreeable smell, and emits red vapours, f   It gives a yel-
low colour to the skin, to silk,  and  to almost all  animal
substances with which it may come in contact.  It dis-
solves and speedily corrodes iron,  copper, zinc,  he. with
the escape of a cloud  of red vapours during the  whole
time its action lasts.   It entirely  destroys the colour of vi-
olets,  which it reddens.   It unites to water with facility;
and the mixture assumes a  green  colour, which  disap-
pears when still further diluted.
   This acid has been  no  where found in a disengaged
state.   It always exists in a state of combination;   and  it
is from these combinations that the art of chemistry ex-
tracts it, to apply to our uses.   The nitrate of potash,  or
common  nitre, is the combination  which is best known,
and is likewise that from which we usually extract the ni-
tric  acid.

  * Dr. Mitchell, of New-York, has  properly considered this acid,
as of animal origin, and as  it is  formed from  putrid animal sub-
stance, he has proposed to call it the septic acid, from  the Greek
word <r*nru>, putrefacio.
  If this nomenclature was adopted, we would have septon;  instead
of azote or nitrogene.
  Septous gas ; instead of azotic gas or nitrogene gas.
  Gaseous oxide of septon ; instead of gaseous oxide of azote or of
nitrogene, or nitrous oxid.
  Septic gas ;  instead of nitrous air.
  Septous acid ;  instead of nitrous acid.
  Septic acid ; instead of nitric acid.
  Septate, septite,  &c.—Am. Ed.
  f The red clouds are formed by the nitrous air, which the acid
contains escaping,  and  uniting to the oxigenous portion of atmos-
pheric air.—Am. Ed. 
          ACID  OF  NITRE,  OR  NITRIC ACID.     167

  The process used in  commerce  to  make aqua  fortis,
consists in mixing one part of saltpetre with two or three
parts of red bolar earth.  This mixture is put into coated
retorts, disposed in a gallery or long furnace, to each of
which is  adapted a  receiver.  The  first  vapour  which
arises in the distillation is nothing but water, which is suf-
fered  to escape at the place of juncture, before the luting:
and when the red vapours  begin to appear, the phlegm
which is condensed in the receiver is poured out; and the
receiver,  being replaced, is carefully luted to the neck of
the retort.   The vapours which are condensed,  form at
first a greenish liquor :  this colour  disappears insensibly,
and is replaced by another which is more or less yellow.
Some chemists, more especially Mr. Baume, were of opi-
nion that the earth acted upon the saltpetre by  virtue of
the sulphuric acid it contains.   But not to mention that
this principle does not exist in all the earths made use of,
as Messrs. Macquer, De  Morveau, and  Scheele have
proved, we know that  pulverized  flints equally produce
the decomposition of saltpetre.   I  am therefore of opi-~
nion  that the effect of these earths upon the salt ought to
be referred to the very evident affinity of the alkali to the
silex, which is a principal component part; and more es-
pecially  to the slight degree of adhesion which  exists be-
tween the constituent principles of  nitrate of potash.
   We decompose saltpetre in our laboratories by  means
of the sulphuric acid.   Very pure  nitrate of  potash  is
taken, and introduced into a tubulated retort, placed in a
sand bath, with a receiver  adapted.   All the  places of
junction are  carefully luted; and as much sulphuric acid
as amounts to half the weight of the salt is poured through
the tubulure ; and the distillation is proceeded upon. Care
is taken to fit a  tube into the tubulure of the  receiver;
the other end of which is plunged  into water, to condense
the vapours,  and to remove  all fear of an explosion.
   Instead of employing the sulphuric acid,  we  may sub-
stitute the sulphate of iron,  and mix it with saltpetre  in
equal parts.   In this case  the residue of the distillation,
when well washed,  forms the mild earth of vitriol made
 use of to polish glass.
   Stahl and Kunckel have spoken of a very penetrating
 aqua fortis,  of  a blue colour, obtained  by the  distillation
 of nitre with arsenic. 
168
PROPERTIES AND  COMPONENT
  Whatever precaution is taken in the purification of the
saltpetre,  and however great the attention may be which
is  bestowed upon its distillation, the nitric acid is always
impregnated with some foreign acid, either the  sulphuric
or muriatic, from which it requires to be purified.   It  is
cleared of the first by redistilling it upon very pure salt-
petre,  which retains the small quantity of sulphuric acid
that may exist in the mixture.*   It is deprived of the se-
cond by pouring into it a few drops  of a solution of ni-
trate of silver.  The muriatic acid combines with the sil-
ver, and is  precipitated with it in  the  form of an insolu-
ble salt.   The fluid is then suffered to remain at rest, and
is afterwards decanted from the precipitate or deposition.
This acid,  so purified, is known  under the name of A-
qua Fortis for Parting, Precipitated Nitrous Acid, Pure
Nitric Acid, &c.
   Stahl had considered the nitric acid as  a modification
of the sulphuric, produced by its combination with an in-
flammable principle.  This opinion has been supported by
 several new facts, in a dissertation of Mr. Pietsh, crown-
 ed by the Academy of Berlin in  1749.
   The experiments of the celebrated Hales led him still
 nearer to this conclusion,  as his manipulations  were suc-
 cessively employed upon the two constituent principles of
 the nitric acid.   This celebrated  philosopher had obtained
 ninety cubic inches of air from half  a cubic inch of ni-
 tre ;  and he proceeded no further in his conclusions, than
 to assert that this air is the principal  cause of the  explo-
 sions of nitre.
    The same philosopher relates that the pyrites  of Wal-
 ton, treated  with equal quantities of spirit of nitre and
 water, produce an air which has die property  of absorb-
 ing the fresh air, which may be made to enter the vessel.
 This great man, therefore, extracted successively the two
 principles of the nitric acid; and  these capital experiments
 put Dr.  Priestley in the road to the discoveries  he  has
 since made.
    It was not however until the year 1776, that the ana-
  lysis of  the nitric acid was well  known.   Mr. Lavoisier,
  by distilling this acid from mercury, and receiving the

    * Or by adding the nitrate of barytes to it.  The sulphuric acid
  will unite with the barytes, and form sulphate of barytes.—Am. Ed. 
PARTS OF NITRIC  ACID.
169
several products in the pneumato-chemical apparatus, has
proved that the  nitric acid, whose specific gravity  is to
that of distilled water as 131607 to 100000, contains—
                     oz.       gross.     grains.
     Nitrous gas     1        7        51 \
     Oxigenous gas  17        7^
     Water         13         —       —
   By combining these  three principles togedier the de-
composed acid was regenerated.
   The action of the nftric acid on most inflammable mat-
ters, consists in nothing more than a continual  decompo-
sition of this acid.
   If the nitric acid be poured upon iron, copper, or zinc,
these metals are instantly attacked with a strong efferves-
cence ; and a considerable disengagement of vapours takes
place, which become of a red  colour  by  their combina-
tion with the atmospheric air,  but which may be retained
and collected in a state of gas in the hydro-pneumatic ap-
paratus.   In all these cases the metals are strongly  ox-
ided.
   The nitric acid,  when mixed with  oils, renders them
thick and black,  converts them into charcoal, or  inflames
them, accordingly  as the  acid is more or less  concen-
trated, or in a greater or less quantity.
   If very concentrated nitric acid be put into an apothe-
cary's phial, and be poured upon charcoal in an impalpa-
ble powder, and very dry, it sets  it on fire instantly, at
the same time that  carbonic acid  and nitrogene  gas are
disengaged.
   The various acids which are obtained by  the digestion
of the nitric acid on certain substances, such as the oxa-
lic  acid,  or acid of sugar, the arsenical acid,  &c. owe
their existence merely to the decomposition of the nitric
acid, die oxigene of which is fixed in combination with
the bodies upon which the acid is distilled.  The facility
with which this acid is decomposed, renders it one of the
most active, because the action of acids upon most bodies
is a consequence of their own proper decomposition.
   The characters of nitrous gas,  which is  extracted  by
the decomposition of the acid," are—1. It is invisible, or
perfectiy transparent.  2. Its specific gravity js rather less
than that of atmospherical air. 3. It is unfit for respiration,
                           Y 
A'U         PROPERTIES AND  COMPONENT

though the abbe Fontana pretends that he respired it with-
out danger.   4.  It does not maintain combustion.   5.  It
is not acid,  according to the experiments of the Duke de
Chaulnes.   6. It combines with oxigene, and reproduces
the nitric acid.
  But what is the nature of this nitrons gas ?  It was  at
first pretended that it consists of the nitric acid saturated
with phlogiston.  This system ought to have been aban-
doned as soon as  it was proved that the  nitric acid  depo-
sited its oxigene upon the bodies on which it acted ; and
that the nitron's gas was less in weight than the  acid made
use of.   A capital  experiment  of  Mr. Canvendish has
thrown the greatest light on the subject.   This chemist
having introduced into a tube of glass seven parts of ox-
igenous gas obtained without nitrous acid, and three parts
of nitrogene gas; or,  by estimating these quantities  in
weight,, ten parts  of  nitrogene to twenty-six of oxigene—
and having caused the  electric spark to pass through this
mixture, perceived that its  volume or bulk was greatly
diminished, and  succeeded in  converting  it  into nitric
acid.   It may be presumed,  from his experiment,  that the
acid is a combination of  seven parts of oxigene, and three
of nitrogene.  These proportions constitute the ordinary
nitric acid;  but when a  portion of its oxigene is  taken
a\vay, it passes to the state of nitrous gas; so that nitrous
gas is a combination of nitrogene gas, with a small quan-
tity of oxigene.
  Nitrous gas may be decomposed by  exposing it to a
solution of the sulphure  of potash,  or hepar of sulphur r
the oxigene gas unites  to the sulphur, and forms  sulphu-
ric acid, while the nitrogene gas remains behind in a state
of purity.
  Nitrous gas may likewise be decomposed by means of
pyrophorus, which burns in this air, and absorbs the ox-
igenous gas.
  The electric spark has likewise the property of decom-
posing nitrous gas.   Mr. Van Marum has  observed that
three cubic inches of the nitrous gas are reduced by elec-
tricity to one cubic inch  and three quarters : and that this
residue  no longer possessed any property of nitrous gas.
Lastly,  according to the experiments of Mr.   Lavoisier,
one hundred grains of nitrous gas contain thirty -two parts 
PARIS OF  NITRIC
A CI Dt.
171
nitrogene, and sixty-eight parts  oxigene:  according  to
the same chemist, one hundred grajns of  nitric acid con-
tain seventy-nine and a half oxigene,  and twenty and a
half nitrogene;  and diis is  the reason  why nitrous gas
should be employed in a less portion than nitrogene gas,
to combine with the oxigene gas, and form the nitric acid.
   These ideas upon the composition of the  nitrous acid,
appear to be confirmed by the repeated proofs we now
have of the necessity of causing substances, which af-
ford much nitrogene gas, to be presented to the oxigene
gas, in order to obtain nitric acid.
   The several states of the nitric acid may be clearly ex-
plained according to this theory :—1.  The fuming nitrous
acid is that in which the oxigene  does not exist in a suffi-
cient proportion ; and we may render the  whitest and the
most saturated nitric acid fuming and ruddy, by depriving
it of a part of its oxigene by means  of metals, oils, in-
flammable substances, he. or  even by disengaging the
oxigene by the simple exposition of the acid to the  light
of the sun,  according to the valuable experiments of Mr.
Berthollet.
   The property which nitrous gas possesses, of absorbing
oxigene to form the nitric acid, has -caused it  to  be em-
ployed to .determine the proportion of oxigene in the com-
position which forms our atmosphere.   The abbe Fonta-
na has constructed, on these principles, an ingenious eu-
diometer, the description and manner of using which may
be seen in the first  volume of Dr. Ingenhousz's experi-
ments upon Vegetables.
   Mr. Berthollet has very justly  observed,  that this eu-
diometer  is inaccurate,  or  productive  of deception—1.
Because it  is difficult to obtain nitrous gas  constantly
formed of the same proportions of nitrogene gas  and ox-
igene;  for they vary,  not only according  to the nature of
the substances upon which the nitric acid is decomposed,
but likewise according!}' as the solution of any given sub-
stance  by the acid is made with greater or'  less rapidity.
If the  acid be decomposed upon a volatile oil,  nothing
but nitrogene gas can be obtained ; if the acid act upon
iron, and it  be much  concentrated,  nitrogene gas only
will be obtained, as I have observed,  &c.  2. The nitriG
acid which is formed by the union of nitrous gas and ox- 
172        NITRATE  OF POTASH, OR NITRE.

lgene,  dissolves  a greater or less quantity of nitrous gas
according to the temperature, the quality of the air which
is tried, the size of the eudiometer,  he.  so that the  di-
minution varies in proportion to the greater or less quan-
tity of nitrous gas obtained by the nitric acid  which  is
formed :  consequently the diminution ought to be greater
in winter than in summer, &c.
  According to the experiments of Mr. Lavoisier,  four
parts of oxigenous gas are  sufficient  to saturate seven
parts and one third  of nitrous gas;  whereas it is found
that nearly sixteen parts of atmospheric air  are required
to produce the same effect:  whence  this  celebrated  che-
mist has concluded, that the air  of the atmosphere does
not in  general contain more than one-fourth of oxigenous
or respirable gas.  Repeated experiments at  Montpellier,
upon the same principle, have convinced me that twelve
or thirteen parts of atmospheric  air  are constantly suffi-
cient to saturate seven parts and one-third of nitrous gas.
  These experiments shew,  to a certain degree of accu-
racy, the proportion  in which vital air exists in the air
which we respire ; but they do not give us any informa-
tion respecting  the noxious  gases  which,  when mixed
with the atmospheric  air,  alter it,  and render it unwhole-
some.   This observation very much curtails the use of
this instrument.
   The combination of the oxigenous  and  nitrous gases
always leaves an aeriform residue, which Mr.  Lavoisier
estimated at about one thirty-fourth of the whole volume:
it arises from die mixture  of the  foreign  gaseous  sub-
stances,  which more  or less affect the purity of the gases
made  use of.
                     ARTICLE I.

                 Nitrate of  Potash.

  The nitric acid,  combined with potash,  forms the salt
so well known under the names of Nitre,  Saltpetre, Ni-
tre of Potash, &c.
  This neutral salt is rarely the  product of any  direct
combination of  its two  constituent parts.  It is  found 
PRODUCTION  OF  NITRE.
173
ready formed in certain places;  and in this manner it is
that the whole of the nitre employed  in  the  arts  is  ob-
tained.
   In the Indies it effloresces on the  surface of unculti-
vated grounds.   The  inhabitants lixiviate these  earths
with water, which they afterwards boil and crystallize in
earthen pots.  Mr. Dombey  has observed a great quan-
tity of saltpetre near Lima, upon eaiths which serve for
pasture, and which produce  only gramineous plants.  Mr.
Talbot Dillon, in his travels into Spain, relates that one-
third of all the grounds, and in the southern parts of that
kingdom even the dust of the roads,  contain saltpetre.*
   Saltpetre is  extracted  in  France from the ruins  and
plaster of  old houses.
   This salt exists ready  formed  in  vegetables, such as
parietaria and bugloss,  he.  and one  of my pupils,  Mr.
Virenque, has proved that it is produced  in  all extracts
which are capable of fermenting.
   The fermentation of  saltpetre may be favoured, by
causing certain circumstances to concur which are of ad-
vantage to its formation.
   In the North of Europe  the saltpetre-beds are formed
with lime, ashes, earth of uncultivated grounds, and straw,
which are  stratified,  and watered with urine, dunghill-wa-
ter, and mother waters.  These beds are defended by  a
covering of heath or broom.   In the year 1775, the king
caused a prize to be proposed by the  Royal Academy of
Sciences at Paris, to discover a method of  increasing the
product of saltpetre in France, and to relieve the people
from  the obligation of  permitting the saltpetre-makers to
examine their cellars, in order to discover and cany- away
saltpetre earths.  Several Memoirs  were  offered on  the
subject, which the Academy united into a single volume ;
and these have added to our knowledge, by instructing us
more especially concerning the  nature of  the  matters
  * There are vast caves in the state of Kentucky, which contain
a yellow clay, which is strongly impregnated with the nitrates of
lime and potash.  Saltpetre caves are also met with in Upper Loui-
siana.   Four men on a trading voyage lately discovered one several
hundred miles up the Missouri.  They spent five or six weeks in the
manufacture of this article, and returned to St. Louis wiih four hun-
dred weight of it,  Medical Repository, vol. i.—Hexade 2. p. 396—
Am. Ed. 
174
PRODUCTION OF  NITRE.
which favour die formation of nitre.   It was known,  for
example, long since, that nitre is formed  in  preference
near habitations, or in earths, impregnated with animal
products: it was likewise known that,  in general, the al-
kaline basis was afforded by die concurrence of a vegeta-
ble fermentation.   Mr.  Thouvenel, whose memoir  was
crowned, has proved that the gas which is disengaged by
putrefaction, is necessary for the formation  of nitre;  that
blood, and next to it urine, were the animal parts  which
were die most favourable to its formation;  that the most
minutely divided and the lightest earths were  the most
proper for nitrification;  that the current of air must be
properly managed, to fix upon these earths the nitric acid
which is formed,  &c.
   It seems to me that Becher possessed  a considerably
accurate knowledge of the formation of nitre,  as appears
from the following passages :
   " Haec enim (vermes, muscae, serpentes) putrefacta in
"  terram abeunt prorsus nitrosam; ex  qua etiam cOm-
"  muni modo nitrum copiosum parari potest,  sola elixa-
"  tione cum aqua communi."—Phys. Subt. lib. i. S. V.
t. i. p. 286.
   " Sed et ipsum nitrum necdum finis ultimus putrefac-
"  tionis est; nam cum ejusdem partes  ignae separantur,
"  relinquae in terram abeunt prorsum puram et insipidam,
"  sed singulari magnetismo praeditam novum spiritum
"  aereum  attrahendi,  rursusque nitrum fiendi."—Phys.
Subt. S. V.  t. i. p. 292.
   From ail the discoveries and observations which have
been hitherto made,  it follows diat, in order to  establish
artificial nitre beds, it is  necessary  that animal putrefac-
tion and vegetable fermentation should concur.  The ni-
trogene gas, in its disengagement from the animal  sub-
stances, combines with the oxigene, and forms the acid,
which again unites with the alkali, whose formation is fa-
voured by the vegetable decomposition.
   When the  manufacturer is  in  possession of saltpetre
grounds, whether by the simple operations of nature or
by the assistance of art, the saltpetre is extracted by the
lixiviation of these earths ;  which lixivium is afterwards
concentrated,  and made  to crystallize.   In proportion as'
the evaporation goes forward, the marine  salt, which al- 
PURIFICATION  OF NITRE.
175
most always accompanies the formation  of nitre,  is pre-
cipitated.   This is taken out with ladles, and set to drain
in baskets placed over the boilers.
   As a great part of the nitre has an earthy  basis, and
requires to be furnished with an alkaline basis to cause it
to crystallize, this purpose is accomplished either by mix-
ing ashes with the saltpetre  earths, or by adding  an  al-
kali ready formed to the lixivium itself.
   Nitre obtained by this first operation is never pure, but
contains sea-salt,  and an extractive and colouring  princi-
ple,  from which it must be cleared.  For this purpose it
is dissolved in fresh water,  which is  evaporated; and to
which bullocks blood may be added,  to clarify the solu-
tion.   The nitre obtained by the second  manipulation is
known by  the  name of Nitre of the  Second Boiling.
If recourse be had to a third operation to purify it, it is
then called Nitre of  the Third Boiling.
   The purified nitrate of potash is employed  in delicate
operations, such as the  manufacture of  gunpowder,  the
preparation of aqua fortis for parting,  and the solution of
mercury,  &c.  The saltpetre of the first boiling is used
in those works where aqua  fortis is made for  the  dyers.
It affords a nitro-muriatic acid, which is  capable of dis-
solving tin by itself.
   The nitrate of potash crystallizes in prismatic  octahe-
drons,  which almost  always represent six-sided flattened
prisms, terminated by dihedral summits*
   It has a penetrating taste followed by a sensation of
coldness.
   It is fusible upon ignited coals; and in this case its acid
is decomposed.   The oxigene unites with the carbone
and forms the carbonic acid;  die  nitrogene gas and the
water are dissipated; and it is this mixture  of principles
which has  been known  under the name of Clyssus of
Nitre.
   The distillation of the nitrate of potash affords twelve
thousand cubic inches of oxigenous gas* for each  pound
of the salt.
   Seven parts of water dissolve one of nitre, at sixty de-
grees of Fahrenheit;  and boiling water dissolves its own
weight of this salt.
* Mixed with azotic air.
■.—*Am. Ed. 
 176        COMPOSITION OF GUNPOWDER.

   One hundred grains of  the  crystals of nitre  contain
 thirty acid, sixty -three alkali, and seven water.
   When a mixture of equal parts  of nitre and sulphur
 are thrown into a red-hot crucible,  a saline substance  is
 obtained, which was formerly called Sal Polycrest of Gla-
 ser,  and  which  has since been considered as  Sulphate  of
 Potash.   If nitre be fused, and a few pinches of sulphur
 be thrown upon this salt infusion, and the whole be after-
 wards poured out  or cast  into  plates, it  forms a  salt
 known by die name of Crystal Mineral.
   A  mixture of seventy-five parts  of nitre, nine and  a
 half of sulphur, and fifteen and a half of charcoal, forms
 gunpowder.  This mixture  is triturated from  ten to fif-
 teen  hours, care  being taken to moisten it from time to
 time.  This trituration is usually performed by pounding
 mills, whose pestles and mortals are of wood.   In order
 to give the powder the form proper to granulate it,  it  is
 passed through sieves of skin,  whose perforations arc of
 various sizes.   The grained powder is  then sifted, to se-
 parate the dust, and it is afterwards carried to  the drying-
 house.  Gun-powder for artillery, op cannon-powder, re-
 ceives no other  preparation ;   but it is necessary  to glaze
 the powder wliich is intended for fowling.   Tliis last pre-
 paration is effected by putting it into a kind of cask which
 turns on an axis, and by whose movement the angles of
 the grains are broken, and their  surfaces  polished.  We
 are indebted to Mr.  Beaume and the chevalier Darcy for
 a series of experiments, in which they have proved—
   1.  That good gunpowder cannot be made without sul-
phur.
   2.  That charcoal  is likewise indispensably necessary.*
   3.   That the quality of gunpowder  depends, ceteris
 paribus,  upon the accuracy  with which the mixture is
 made.
   4.  That the effect of powder  is  greater when  simply
dried than when it is granulated.f

  * Coal for the manufactory of gunpowder, should be made in iron
 cylinders.   The advantages of this process are so considerable, that
 the proportion of powder, used for the several pieces of ordnance
in  the navy and army of Great-Britain, has been reduced one third;
when the coal was prepared in, this manner.—Am. Ed.
  | There are several methods of proving the goodness and strength
of gunpowder.  The following is  the best: Lay two or three small 
FULMINATING
POWDER.
177
   The effect of gunpowder depends upon the  rapid de-
composition which is made in an instant of a considerable
mass of  nitre,  and the sudden formation  of those  gases
which  are the immediate product.  Bernoulli,  in the last
century,  ascertained the development of air by the defla-
gration of  gunpowder:  he placed four  grains  of powder
in a recurved tube of  glass, plunged the tube  in water,
and set fire to the gunpowder by means of the  burning-
glass ;  after the combustion  the interior  air occupied a
larger  space, so that the space abandoned by the  water
was such as would have contained two  hundred grains of
gunpowder.—Hist, de l'Academie des  Sciences de  Paris,
1696,  t.  ii. Memoire de  M.  Varignon  sur le Feu  et la
Flamme.
   The fulminating powder,  which is made by the  mix-
ture and trituration of three parts of nitre, two of salt of
tartar,  and one of sulphur,  produces effects  still  more
terrible.   In order to obtain the full effect, it is  exposed
in a ladle to a gentle heat; the mixture melts,  a sulphu-
reous  blue flame appears, and die explosion takes  place.
Care must be taken to  give  neither too  strong  nor too
slight  a degree of heat.   In  either case  the  combustion
of the principles takes place  separately, and without ex-
plosion. *

heaps on separate pieces of clean  writing paper, within a short dis-
tance of each other, and set fire to one of them ; if the flame ascends
quickly, with a good report, leaving the  paper  free  from  specks,
and does not burn it into holes, and if the sparks fly otT, setting fire
to the adjoining heaps, the  goodness of the ingredients, and proper
manufacture of the powder, may be safely inferred ; if otherwise, it
is either badly made,  or the ingredients are impure.—Am. Ed.
  * When fulminating powder is  heated, the  sulphur unites to the
potash,  and forms sulphuret of potash or liver of sulphur, before de-
toning.  Sulphurated hydrogen gas is disengaged from the sulphu-
ret of potash, and oxigenous gas from the  nitre.  These two airs
unite, and are inflamed by a part of the sulphur,  which kindles by
itself.   They strike the atmospheric air with  such rapidity, that it
resists  them in the same manner, as the sides of a gun  barrel re-
sist gunpowder.—Am. Ed.
z 
178
NITRATE OF  SODAV
                       ARTICLE II

                     Nitrate of Soda.

   This salt has received the name of Cubic Nitre on ac
count of its form;  but this denomination is not  exact,
because it affects a figure constantly rhomboidal.
   It has  a cool, bitter taste.
   It slightly attracts the humidity of the air.
   Cold water, at sixty  [degrees of Fahrenheit's thermo-
meter, dissolves one-third of its  weight; and  hot water
scarcely dissolves more.
   It   fuses  upon burning coals with a  yellow colour;
whereas common nitre  affords  a white flame, according
to Margraff—24 Dissert, sur  le  Sel Commun,  t.  ii. p.
343'.
   100 grains of this salt contain 28.80 acid, 50.09 alkali,
and 21.11 water..
   It is almost always the product of ait.*

                    * Nitrate  of Ammoniac.
  The best  method of preparing this salt, is by the  direct  com-
bination of the nitric acid, and the carbonate of ammoniac.
  The nitrate  of ammoniac varies very  much  in  appearance, ac-
cording to the temperature at which its solution is evaporated.  If
a heat of about 70° or  80°, and by slow cooling, it is obtained in six-
sided prisms, terminated by six-sided pyramids.   When the solution
is evaporated at 212?,  the crystals are channelled and have a fibrous
texture, or they are formed of long soft  elastic threads.   When
dried in a heat of about 300° it assumes the form of a white compact
mass.
  It has an acrid, bitter and disagreeable taste.
  It is soluble  in two  parts of water, at a temperature of 60°  of
Fahrenheit,
  It dissolves in half its weight of boiling water.
  It deliquiates when  exposed to the action of atmospheric air.
  When the salt in the state of prismatic crystals, is heated,  it be-
comes  fluid, at a temperature below 300°, between 360°. and  400°,
it boils without decomposition, but when heated to 450 it is gradu-
ally decomposed, without losing its water of crystallization.
  The compact nitrate of ammoniac undergoes no change, until it
is exposed to a temperature higher than 260°.  Between 275Q and
:>00°, it sublimes slowly without decomposition.  At 320°, it  melts
and is  slowly decomposed.
  When the salt undergoes decomposition at a temperature not ex-
ceeding 500?, it is converted into the dephlogisticated nitrous  air oi 
MURIATIC  ACID.
179
                        CHAPTER IV.

              Concerning the Muriatic Acid.*


      THIS acid is generally known by the  name  of Ma-
       rine Acid,  and it is still distinguished among arti-
sans by the name of  Spirit of  Salt.

  * We are ignorant of the base of this acid.   Professor Pachioni
has asserted, that it may be formed by abstracting a portion of ox-
igene from water, by the Galvanic influence.  We cannot adopt this
opinion, until his experiments are confirmed by other chemists.—;
Am. Ed.
 Dr. Priestley, the gaseous oxide of azote of the Dutch chemists, and
 the nitrous oxide of Mr. Davy.
    When it is exposed to  heat above 600°, it explodes in  a  violent
 manner, and is converted into nitrous acid, nitrous gas water and
 azotic gas ; hence it is called nitrum fammans.
    When the nitrous oxide is formed from the nitrate of ammoniac,
 part of the oxigene of the nitric  acid, of  the nitrate of ammoniac,
 unites with the hydrogene of the ammoniac, and forms water;  ano-
 ther part of the oxigene of  the acid unites to the azote of the  am-
 moniac, and makes the nitrous oxid.
   This oxide is always an artificial production.
   A candle burns with a beautiful blue flame in this  gas, and be-
 fore its extinction the white inner flame becomes surrounded with a
 blue one.
   This double flame arises from some of the vapour of the nitrous
 acid being mixed with the nitrous oxide,  for it  can be formed by
 plunging a taper in atmospheric air containing nitrous  acid vapour,
 or into a mixture of nitrous oxide  and azotic gas, through which the
 nitrous acid vapour is made to pass.
   Phosphorus introduced into a jar of nitrous oxide in a state of ac-
tive inflammation, burns in the same manner as in oxigene gas.
   Sulphur introduced into it, burning with a feehle blue  flame,  is
Immediately extinguished, but when in a state of vivid inflammatiorj,
it  burns with a rose coloured flame.
   Iron wire placed in it with a small piece of wood fixed to it, when
inflamed,  burns in a vehement manner, and throws out bright scin-
tilating sparks.
   Nitrous oxide is readily absorbed by water, and may  be  expelled
from it by  means of  heat. 
180
MURIATIC  ACID.
   It is  lighter  than  the two  preceding acids; it has a
strong penetrating smell,  resembling that of saffron,  but

  It has no acid or alkaline properties, as it does not change  blue
vegetable colours.  It has a sweet taste.  The alkalis have no action
upon it.  It explodes with  a loud noise,  when mixed with hydro-
gene gas.  It is fatal to animal life.
  Nitrous oxide when taken into the lungs, by breathing out and into
a varnished silk bag or large bladder, in a dose of from four to six
quarts, causes the most extraordinary  effects.  On some persons
it produces the most  agreeable  sensations, and immoderate fits of
laughter.   It affects others with vertigo, dizziness, temporary mad-
ness, fainting, &c.  When  Mr.  Humphrey Davy, to whom we  are
indebted for ascertaining the effects of this wonderful agent, breathed
seven quarts of it, muscular motions were produced to a certain ex-
tent ; sometimes he manifested his pleasure by stamping or laugh-
ing, and at other times,  by dancing round the room and vociferat-
ing.  At another time, having breathed nine quarts of the air, he
first lost the perception  of  external things, and a vivid  and intense
recollection of some former experiments, passed through his mind,
so that he called out, "  What  an amazing  concatenation of
ideas !"
  When he breathed twenty quarts, a thrilling sensation from  the
chest to the extremities, was almost immediately produced. By de-
grees the pleasurable sensations were increased ; he lost all connec-
tion with  external things, trains of vivid visible images passed
through his mind, and were connected with words in such a  man-
ner, as to produce perceptions perfectly novel.  He  supposed  that
he existed in  a world of newly connected and newly modified ideas.
He theorized and imagined that he  made discoveries.  Upon  wak-
ing from this semi-delirious trance, indignation and pride  were the
first feelings produced, by  the sight of the persons about him.   His
emotions were'enthusiastic and  sublime, and  he exclaimed  with a
loud voice, " Nothing  exists but thoughts !  the universe
IS COMPOSED OF IMPRESSIONS*, IDEAS,  PLEASURES, AND  PAINS."
After tins, he expressed his pleasure, by laughing and stamping.
  Mr. Tobin having taken two quarts into his lungs, laughed, stag-
gered, threw  himself into a variety of theatrical attitudes, traversed
the laboratory with a quick step, and his mind was elevated  to a
most sublime height.
  Mr. Wedgwood had six quarts administered to him, and as  soon
as he had made two or three inspirations, he felt himself much af-
fected, and his respiration hurried, which  effect increased rapidly,
until he became, as it were, intranced, when he threw the  bag from
him, and kept breathing on furiously with an open mouth, and hold-
ing his nose with his hand, having no  power to take it  away, al-
though aware  of the  ridiculousness of his  situation.  He had a
strong inclination  to make antic motions with  his  hand and feet.
When the first strong sensations went off, he felt, as it were, lighter
than the atmosphere, and  as if he was going to mount to the top of
the room. 
MURIATIC  ACID.
181
infinitely  more pungent;  it  emits white vapours when it
is concentrated;  it precipitates silver from its solution in

  Mr. George Burnet felt a general swell of sensations, vivid, strong,
and inconceivably pleasurable, which  mounted so  fast, that had he
not desisted to breathe the gas,  he would have fainted from ecstacy.
  Southey, the poet, upon breathing the gas, exclaimed, u The air of
the highest possible of all heavens, must consist of this gas."
  In the year 1802, the editor of this work attempted to prepare a
large quantity of the nitrous oxide, from the nitrate  of ammoniac,
made by decomposing the nitrate of potash by the sulphate of am-
moniac, and by adding the nitric acid to sal ammoniac.
   A great number of gentlemen, belonging to  his chemical class,
who intended to breathe the  gas, were present in the  morning,
when he was filling his air holders vuth it, and saw all the opera-
tions going forwards.
   In the afternoon  being at his laboratory at two o'clock, the air
was examined and found to be extremely impure,  having  made use
of too great a degree of heat in generating it.
   Expecting the gentlemen at  three o'clock, the impure  air  was
thrown away, and the air holders filled with atmospheric air.
   This air  was breathed by a variety of  persons, under  the  im-
pression that it  was the nitrous oxide, and the greater part of them
were affected with quickness of pulse, dizziness, vertigo, tinnitus au-
rium, difficulty of breathing, anxiety about the breast, &c.
   The  following is  a  letter received from one of the gentlemen:
   " The nitrous oxide produced no sensible effect, for perhaps the
space of a  minute, after I began to  breathe  it.   Soon after I  was
affected with a tinnitus aurium, which affected the sense of hearing,
in the same manner as water, in a state immediately preceding ebul-
lition does.   At the same time, 1 had a sensation'similar to that pro-
duced by swinging ;  afterwards  a difficulty  of breathing gradually
came on, which at  length necessitated me to discontinue the respi-
ration of the air.   The difficulty of breathing, and the tinnitus then
soon subsided.  But the  peculiar sensation in my breast,  continued
some time longer, which was succeeded by slight nausea, which con-
tinued six or eight  hours.
   A short account  of the effects of the atmospheric air, was sent to
Dr. Mitchell, who  published it in the Medical Repository of New-
York, vol. v. p.  461.
   For many years after this, not seeing the  experiments of Mr. Hum-
phrey Davy, on  this subject confirmed by other chemists, I believed
that the influence of the imagination, caused all the effects, ascribed
to the nitrous oxide.
   In the winter of  1806, having prepared  a quantity of this gas, ex-
tremely pure, from  the nitrate of ammoniac, made by the direct com-
bination of the nitric acid and the carbonate of ammoniac, two quarts
of it were administered to Mr.  Henry  Latrobe,  fourteen years of
age, who breathed  it in a very fair manner.  In one minute he was
affected in a most  violent manner.   He walked up and down the la-
boratory with a quick step,  elevating one leg after  the other, and 
182
MURIATIC  ACID.
the form of an insoluble salt, &c.  This acid has no where
been found disengaged ;  and,  to obtain it in this state,  it

then suddenly throwing it down on the ground.  He laughed immo-
derately  and convulsively, the tears rolled down his cheeks in large
drops, and he frothed at the mouth.
   Witnessing these effects, and knowing the impossibility of coun-
terfeiting such  symptoms, I  immediately resolved to try the effects
of the gas on other persons, in doses of two and four quarts.
   Mr. J. D. Maclean upon breathing the gas, fainted away, and re-
covered in about three minutes.
   Mr. George Thornton looked wild, jumped over a high bench, and
the effect suddenly ceased.  Mr. Martin raised his hands above his
head, and jumped about the room.
   Mr. Pope placed his arms a kimbo, and surveyed the audience
with great contempt.
   Mr. William Barton was very much deranged ; he ran about the
laboratory, bellowed like a mad bull,  and struck  at  every person
near him.   A week after, the gas  being administered to him a se--
cond time, produced the same effect.
   He felt a  great increase of strength  after recovering from the ef-
fects of the air.
   It was with much difficulty I could separate the  mouth piece  of
the bladder from his mouth.
   Mr. N. S. Allison fainted,  but recovered in a few minutes,   Upon
breathing the air, seven days afterwards, the same  effect  was pro-
duced.
   Mr. Thomas Prioleau exclaimed " I am in heaven, ye gods, stars,
comets, meteors,  Mahomet's a jackass, the elysian fields are hell com-
pared with tliis" and then fainted.
   Mr, Robert Patterson was  affected with violent laughter.
   Mr. Samuel Jackson in the same  manner.
   Mr. Peter Curtis laughed very heartily.
   A week after, having a very large air holder, filled  with atmos-
pheric air, along side of two others, containing nitrous oxide, he
breathed the atmospheric air, but no effect was produced.
   Mr. Gerard Snowden fainted, but soon recovered.
   Mr. William  Handy laughed and fainted.
   Mr.  William  Tyler  fainted and recovered  in* three minutes.
Seven days afterwards, trying the air, a second time,  the same ef-
fect was produced.
   Mr. Cornelius  Dupont laughed and fainted.  Baron  John de
Bretton experienced pleasurable sensations.
   Mr. Benjamin Kugler laughed.  Upon giving him  atmospheric
air, a week after  this, he immediately knew the difference in the
gases, and it produced no effect.
   Mr. Thomas  Lewis was very much enraged.   He caught me by
the collar, pulled at my cravat, tore my coat, run  about the room*
and struck at every person near him.
   Mr. Evans breathed atmospheric air.
.   It produced no effect. 
          BISTILLATION  OF  MURIATIC ACID.      183


is necessary toTdisengage it from its combinations.   Com-
mon salt is usually employed for this purpose.
   The spirit of salt of commerce is obtained by a process
little differing from  that which is used in the extraction of
aqua fortis.   But as this acid adheres  more strongly to its
basis,  the product is very weak, and only part of the ma-
rine salt is decomposed.
   Flints pulverized and mixed with this salt, do not sepa-
rate the acid.  Ten pounds of flints in powder, treated by
a violent fire with two pounds of the salt,  did  not afford
me any other product than a mass of the colour of litharge.
The fumes were not perceptibly acid.   If clay, which has
once served to decompose marine salt,  be  mixed  with a
new quantity of the same  salt, it will not  decompose an
atom of it,  even though the mixture be  moistened  and
formed into  a paste.  These experiments have been se-

   Mr.  Wharton after fairly breathing four quarts of the gas, was be-
ginning to be affected.  He called out in a rapid manner, " Give me
another bottle, give me another bottle."
   The nitrous oxide was tried by fifteen other persons, without pro-
ducing any effect.  Some of them took it into  their lungs very fair-
ly, others were frightened, and mixed it with the air of the atmos-
phere.
   I am now convinced  the gas produces all the effects ascribed to it,
by the  justly  celebrated  Mr.  Davy ; and I am happy in having this
opportunity of confirming his experiments.
   The following letter on this subject, was received from professor
Silliman, of Yale college, Connecticut.
   I have lately given the nitrous oxide a full and fair trial,  and the
result  has been such as to confirm in the most satisfactory manner,
Mr. Davy's account of the  effects of this wonderful agent.
   In my own case, after only two inspirations, I felt a momentary loss
of distinct thought, then sensations of such pure and vehement de-
fight, tingling through  every fibre of my frame, to the extremities of
my toes and fin/ers. that after failing in  an  attempt to express to
my friends by articulate words  the pleasure I felt, I demonstrated it
by leaping up and down, stamping on the floor, and loud convulsive
laughter.
   One  of our gravest citizens, a man of thirty-eight or forty years
of age, was made  to caper about like a monkey, with all the extra-
vagant  gestures of a tragedian, and the grimaces of a Harlequin.
Some effect was produced on all who breathed the gas, and the full
effect was manifested, in six instances out of eight.  One of these
took place before the class and  many spectators, and was so market}
as to banish every doubt.  Six or eight quarts breathed into and  OHt
of a silk bag, will always  I believe produce the  effect.—Am. Ed. 
184
DISTILLATION OF  MURIATIC  ACID.
veral times repeated in  my manufactory,  and have con-
stantly exhibited the same results.
  The sulphate of iron, or martial vitriol, which so easily
disengages the nitric  acid, decompose marine  salt; but
very imperfectly.
  The  impure soda known in  France by the  name  of
Blanquette, and in which my analysis has exhibited twen-
ty-one pounds of common salt out of twenty-five, scarce-
ly affords  any muriatic acid when  it is distilled with the
sulphuric acid; but it affords abundance of sulphureous
acid.   Mr. Berard,  the  director of my manufactory at-
tributed these results to  the  coal contained in  this soda,
which decomposed the sulphuric acid.  He therefore cal-
cined the  blanquette to  destroy the charcoal:  and then
he found he could treat it in the same manner as common
salt, and with the same success.
  The sulphuric  acid is usually employed to decompose
marine salt.   My method of proceeding consists in drying
the marine salt, pounding it, and putting it into a tubulat-
ed retort placed upon a sand bath.   A  receiver  is adapted
to the retort,  and  afterwards two  bottles,  after  the man-
ner of Woulfe, in which I distribute a weight of distilled
water equal to that of the marine salt made use  of.    The
joinings of the vessels are then luted, but with the greatest
caution; and when the apparatus is dius fitted up, a quan-
tity of sulphuric acid is poured through the tubulure equal
to half the weight of the salt.   A considerable ebullition is
immediately excited; and when this effervescence is slack-
ened, the  retort is gradually heated, and the mixture made
to boil.
   The acid is disengaged  in the state  of gas;  and mixes
rapidly with  the  water,  in which it produces a considera-
ble degree of heat.
   The water of the  first bottle is usually  saturated with
the acid gas,  and  forms a very concentrated and  fuming
acid; and though the second is weaker, it may be carried
to any desired degree of concentration, by impregnating it
with a new quantity of the gas.
   The ancient chemists were divided  respecting  the  na-
 ture of the muriatic acid.   Becher supposed it to be the
 sulphuric acid modified  by his mercurial earth. 
            OXIGENATED MURIATIC ACID.        185

  This acid is susceptible of combining with an additional
dose of oxigene;  and, what is very extraordinary, it be-
comes more volatile in consequence of this additional
quantity;  whereas the other  acids appear  to acquire  a
greater degree of fixity in the same circumstances.  It
may even be said, that its acid virtues become weaker in
this case,  since its affinities  with alkalis diminish;  and it
is so far from reddening blue vegetable colours, that it de-
stroys them.
  Another phenomenon not less interesting, which is pre-
sented to  us by this new combination, is, that though the
muriatic acid seizes the oxigene with avidity, yet it con-
tracts so weak  an union with it, that it yields it to almost
all bodies, and  the mere action of light alone is sufficient
to disengage it.
   It is to Scheele that we are indebted for the discovery
of the oxigenated muriatic acid.   He formed it  in the
year  1774, by employing  the muriatic  as a solvent for
manganese.  Fie  perceived that  a gas was disengaged,
which possessed the distinctive smell of aqua regia; and
he was of opinion that in this case the muriatic acid aban-
doned its phlogiston to the manganese; in consequence of
which notion "he  called it  the  Dephlogisticated Marine
Acid.  He took notice of the principal and truly astonish-
ing properties of this  new  substance;  and  all chemists
since his  time  have thought their attention well employed
in examining a substance which  exhibits such  singular
properties.
   To attract this acid, I place a large glass alembic of one
single piece upon a sand  bath.  To the alembic I adapt a
small receiver; and to the receiver  three or four small
bottles nearly filled with distilled water,  and arranged  ac-
cording to the method of Woulfe.  I dispose the receiver
and the bottles in a cistern, the places  of junction  being
luted with fat  lute, and secured with rags soaked  in  the
lute  of lime and  white  of egg.  Lastly, I surround the
 bottles with pounded, ice.  When the apparatus is thus
 disposed, I introduce into the alembic half a pound of man-
 ganese of Cevennes, and pour upon it, at several repetiti-
 ons, three pounds of fuming muriatic acid.   The quantity
 of acid which  I pour at once is three ounces; and at each 
186
OXIGENATED MURIATIC  ACID.
time of pouring a considerable .effervescence is  excited.
I do not pour  a new quantity until nothing more comes
oyer into the receivers.  This method of proceeding is in-
dispensably necessary,  when  the  operator is desirous of
making his process with a definite quantity of the mate-
rials.   For if  too  large a quantity of acid be poured at
once, it is impossible to restrain the vapours; and the ef-
fervescence will throw a portion of the manganese into the
receiver.   The vapours which are developed by  the affu-
sion of muriatic acid are of a greenish yellow colour; and
they communicate  this colour to the water when they
combine with it.  When this vapour is concentrated by
means of the  ice,  and the water is saturated with it,  it
forms a scum at the surface, which is precipitated through
the liquid, and resembles a congealed oil.   It is necessa-
ry to assist the action of the muriatic acid by means of a
moderate heat applied to the sand bath.   The secure lut-
ing of the vessels is also an essential circumstance;  for the
vapour which might escape is suffocating, and would not
permit the chemist  to inspect his operation closely.   It is
easy to discover the place where it  escapes through the
lutes, by running a  feather dipped in volatile alkali over
them;  the combination of these  vapours instantly forms a
white cloud, which renders  the place  visible where the
vapour escapes.  An  excellent Memoir of Mr. Berthol-
let, published in the Annales  Chimiques, may be consult-
ed  upon the oxigenated muriatic acid.
   The same oxigenated muriatic acid may be obtained by
distilling, in a similar apparatus, ten pounds of marine salt,
three or four pounds of manganese, and ten pounds  Of
sulphuric acid.
   Mr. Reboul has observed that the concrete state of this
acid is a crystallization of the  acid, which takes place at
three degrees  of temperature  below the freezing point of
Reaumur.  The forms which  have been  observed are
those of a quadrangular prism truncated very obliquely,
and terminated by a lozenge.   He  has likewise observed
hollow hexahedral pyramids on the surface of the liquor.
   To  make use of the oxigenated acid in the arts, and in
order to  concentrate a greater quantity in  a  given volume
of water, the yapour is made to pass through a solution of
alkali.  A white precipitate is at first formed in the liquor; 
             OXIGENATED MURIATIC ACID.        187

but a short time afterwards die deposition diminishes, and
bubbles are disengaged, which are nothing but the carbo-
nic acid.   In this case two salts are formed, the oxigenated
muriate, and the ordinary muriate.   The mere impression
of light is sufficient to decompose the former, and convert
it into common salt.   This lixivium contains, indeed, the
oxigenated acid in a stronger proportion.   The execrable
smell of the  acid is much weakened - It may be employ-
ed for various uses with the same success, and with great
facility;  but the effect is very far from corresponding with
the quantity  of oxigenated acid which enters into this com-
bination, because the virtue of a great part is destroyed by
its union with the alkaline basis.
   The oxigenated muriatic acid has an excessively strong
smell.  If acts directly on the larynx, which it stimulates,
excites coughing, and produces violent head-aches.
   Its taste is sharp and bitter.   It  speedily  destroys the
colour of tincture  of turnsol.  But it appears that the
property  which  most oxigenated  substances possess,  of
reddening blue colours, arises only from the combination
of oxigene with the colouring principles;  and that,  when
this combination is very strong and rapid, the colour is de-
stroyed.
   The oxigenated muriatic acid with which a solution of
caustic alkali is saturated, affords, by evaporation in vessels
secluded from the light, common muriate and oxigenated
muriate.   This last detonates upon charcoal; is more so-
luble in hot  than in cold  water; crystallizes, sometimes in
hexahedral  lamina?,. and oftener   in rhomboidal plates.
These crystals have an argentine brilliancy, like mica.  Its
taste is faint; and its crystals, when they are dissolved in
the mouth, produce a sensation of coolness resembling that
of nitre.*

   * The taste of oximuriate of potash is cooling, austere, and disa-
greeable.  It phosphoresces when rubbed smartly, or rather emits a
number of sparks of fire.
   It is soluble in seventeen parts of water, at the temperature of 60°,
and in 2\ parts of boiling water.   It is not altered by exposure to the
air.  It exhibits astonishing properties, when mixed with combustible
bodies.  It is decomposed by all these substances, and the decompo-
sition is generally attended with violent detonations.
   It cannot be kept in contact with sulphur, as it  detonates spontane-
ously with  this substance.  If the sulphuric acid be poured upon a 
188
OXIGENATED MURIATIC  ACID.
   Mr. Berthollet has ascertained, by delicate experiments
 that the oxigenated muriatic acid which exists in the oxi-
 genated muriate of potash, contains more  oxigene than
 an equal weight of oxigenated muriatic  acid dissolved in
 water; and this has  led him to consider the  oxigenated
 acid combined in the muriate as being  superoxigenatcd.
 He considers the common muriatic gas with relation to the
 oxigenated muriatic  gas, the  same as  the nitrous  gas or
 sulphureous gas with respect to  the  nitric  and sulphuric
 acids.  He pretends that the production of the simple mu-
 riate and the oxigenated muriate in the  same operation,
 may be. compared  to the action  of the nitric acid, which
 in  many  cases produces nitrate and  nitrous gas.   Hence
 he has considered the  muriatic  acid  as a pure radical,
 which, combined with a greater  or less  quantity of oxi-
 gene,  forms either  simple muriatic acid gas, or the oxige-
 nated muriatic gas.
   The oxigenated muriates  of soda do  not  differ from
 those  of potash, but  in being more deliquescent and solu-
 ble in alcohol,  like all the salts of this nature.


 mixture of this salt and sulphur, charcoal, or the metals, or oil of tur-
 pentine, or almost any combustible, a very brilliant flame is emitted.
   When it is triturated in a mortar, with cotton cloth, small repeated
 explosions are heard,  similar to the crack of a whip, and if the cot-
 ton be dry and warm, it sometimes takes fire.
   Mr.  Robert mentions a variation in the method of making the de-
 tonations with oximuriate of potash, and various combustible  sub-
 stances, which form a number of easy  and amusing  experiments.  It
 is known that if a quantity of sulphuric acid is poured on these mix-
 tures, they will suddenly inflame.  Mr. R. finds the same effect when
 they are merely touched with a rod of glass dipped in  the acid.  In
 this manner he inflamed three parts of the oximuriate, and one of
 sulphur ; three of the  same salt, half a part  of charcoal, and as much
 sulphur; equal parts of the salt and regulus  of antimony ; equal parts
 of the salt and ore of  antimony ;  equal parts of the ealt and kermes
 mineral; equal parts of  the salt and arsenic ; three parts of the  salt
 and one of sugar;  one and a half of the salt  and three of gunpowder;
 and masses made with alcohol, olive oil and the oximuriate.  A pis-
 tol was fired by being first loaded in the usual way, the pan filled with
 a mixture of gunpowder and the oximuriate, and then touched with
 the sulphuric acid.  The following is a very entertaining experiment
 given by the same : Fill a bladder with hydrogen gas, furnished with
 a brass tube ; wet the  end of the tube  with sulphuric acid, sprinkle
 the moistened end with oximuriate of potash in fine powder, and at
 the same moment press  the bladder ; the hydrogen gas, in passing
 through, will be inflamed, the moment it touches the acid salt, as if
by a spark of electricity.  (Annales de Chimic, torn. 44.) —Am. Ed. 
         GUNPOWDER WITH MURIATIC SALT.     189

  The oxigenated muriate of potash gives out its oxigene
in the light, and  by distillation  as  soon as  die vessel is
heated to redness.   One hundred grains of this salt afford
seventy-five cubic inches of oxigenous gas reduced to the
temperature of twelve degrees of Reaumur.   This air is
purer than the others, and  ma)'  be  employed for delicate
experiments, the oxigenated muriate of potash, when crys-
tallized, does not trouble the solutions of nitrate  of lead,
of silver, or of mercury.
  Mr. Berthollet has fabricated gunpowder,  by substitut-
ing the oxigenated muriate instead of  saltpetre.   The ef-
fects it produced were quadruple.  The  experiment in the
large  way, which was made at Essone,  is  but too well
known, by the death of Mr. Le Tors and Mademoiselle
Chevraud.  This powder exploded the moment the mix-
ture was triturated.
   The oxigenated muriatic acid whitens thread and cot-
ton.  For this purpose the cotton is boiled in a weak alka-
line lixivium; after which the  stuff  is wrung out, and
steeped in the oxigenated acid.  Care is taken  to move
the cloth occasionally in the fluid, and to wring it out.  It
is then washed in a large quantity of  water,  to deprive it
of the smell with which it is impregnated.
   I have applied this known property to the whitening of
paper and old prints: by this means they obtained a white-
ness which they never before  possessed.  Common ink
disappears by the action of this  acid; but printers' ink is
not attacked by it.
   Linen and cotton cloths, and paper, may be bleached by
the vapour of the oxigenated marine  acid.   I have made
some experiments in the large way, which have convinced
me of the possibility of applying this method to the arts.
The memoir in which I have given an account of my ex-
periments, will be printed in the volume of the Academy
of Paris for the  year 1787.
   The oxigenated muriatic acid thickens oils;  and oxides
metals to such a degree, that this process may be advanta-
 geously used to fonn verditer.
   The oxigenated muriatic acid dissolves metals without
 effervescence; because its oxigene is sufficient  to oxide
 them without the necessity of die decomposition of water
 and consequently of the disengagement  of gas. 
190
MURIATE OF POTASH.
   This acid precipitates mercury from its solutions,  and
converts it into the state of corrosive sublimate.
   It converts sulphur into sulphuric acid, and instantly de- -
prives the very black sulphuric acid of its colour.
   When mixed with nitrous gas, it passes to the  state
of muriatic acid,  and converts  part of the gas into nitric
acid.
   When exposed to  light, it affords oxigenous gas,  and
the muriatic  acid is regenerated.
   The muriatic acid acts very efficaciously upon metallic
oxides, merely in consequence of its becoming oxigenated;
and in this case it forms with" them salts, which are more
or less oxigenated.

                      ARTICLE I.

                  Muriate of Potash.

   This salt is still distinguished by the name of Febrifuge
salt of Sylvius.
   It has a disagreeable strong bitter taste.
   It crystallizes in cubes, or in tetrahedral prisms.
   It decrepitates upon coals; and when urged by a violent
heat it fuses, and is volatilized without decomposition.
   It requires three times its  weight of water, at the tem-
perature of sixty degrees of Fahrenheit, for its solution.
   It is subject to scarcely any alteration in the air.
   One  hundred grains  of this salt contain 29.68  acid,
63.47 alkali,  and  6.85  water.   It is frequently met with,
but in small  quantities,  in the water of the  sea, in plaster,
in the ashes of tobacco, &c.   The existence of this salt
in the ashes of tobacco might with justice  have surprised
me, as I had reason to  expect the muriate  of  soda which
is employed  in the operation called watering.   Was  the'
soda metamorphosed into  potash by  the  vegetable  fer-
mentation ?   This may be determined by direct experi-
ments. 
MURIATE OF SODA, OR COMMON SALT.     191
                     ARTICLE II.

                  Muriate of Soda.

  The received names of Marine Salt,  Common  Salt,
and Culinary Salt, denote the combination of muriatic acid
with soda.
   This salt has a penetrating but not bitter taste.   It de-
crepitates on coals, fuses, and is volatilized by the heat of
a glass-maker's furnace, without decomposition.
   It is soluble in 2.5 times its weight of water, at sixty
degrees of Fahrenheit's thermometer.
   One  hundred grains of this salt contain  33.3 acid, 50
of alkali, and 16-7 of water.
   It crystallizes in cubes.   Mr. Gmelin  has informed us
that the salt of the salt lakes  in the environs of Sellian on
the banks of the Caspian sea, forms cubical and rhomboi-
dal crystals.
   Mr.  De Lisle observes,  that a solution of marine salt,
left to insensible evaporation during  five years by Mr.
 Rouelle, had formed regular octahedral crystals resembling
 those of alum.
   Marine salt may be obtained in octahedrons, by pouring
fresh urine into a very pure  solution  of  fresh salt.   Mr.
 Berniard is convinced that this addition changed only the
 form of the salt, without altering its nature.
   Common salt is found native in many  places.  Catalo-
 nia, Calabria,  Switzerland, Hungary,  and Tyrol possess
 mines, which are more or  less  abundant.   The richest
 salt mines  are those  of Wieliczka in Poland.   Mr. Ber-
 niard has given us a description of them in the Journal de
 Physique;  and Mr. Macquart, in his Essays on Minera-
 logy, has added interesting details concerning the working
 of these mines.*
   Our salt springs in Lorraine and Franche-comte,  and
 some indications  afforded by Bleton, have appeared suf-

   * There are two mountains of common salt in Russia near Astra-
 can ; several in the kingdom of Tunis  and Algiers, in  Africa ; and
 a number in Asia.  It is said there is a mountain of solid rock-salt, 
192
MURIATE OF  SODA, OR COMMON SALT.
sufficient motives to Mr.  Thouvenel to presume that salt
mines  exist  in  our kingdom.   This  chemist expresses
himself in the following manner:
   " At the distance of two leagues from Saverne, between
the village of Huctenhausen and that of  Garbourg,  in  a
lofty mountain called Pensenperch, there  are two great re-
servoirs of salt water;  the one to die east at the head of a
large deep and narrow valley, which  is called the great
Limerthaal;  the other to the west, upon the opposite slope,
towards Garbourg.  They communicate  together by  five
small streams, wliich are detached from the  upper reser-
voir, and unite in the lower one. From these two salt reser-
voirs flow two large streams; the upper runs into Franche-
comt6, and the lower into Lorraine, where they supply the
well-known salt works."
   The waters therefore flow to the distance of seventy
leagues from the reservoir.*
   Salt mines appear to owe their origin  to the drying up
of vast lakes.  The shells and madrepores found in the
immense  mines of Poland are proofs of marine deposi-
tions.   There are likewise some seas in which the salt is
so abundant, that it is deposited at the bottom of the wa-
ter ; as appears from the analysis of the water of the  lake
Asphaltites,  made by Messrs. Macquer and Sage.
   This native salt is often coloured;  and as in this state
it possesses  considerable brilliancy,  it is called Sal-gem.
It almost always contains an oxide of iron, which colours
it.
   As  these  salt mines are neither sufficiently abundant to
supply the wants of the inhabitants of the globe, nor dis-

without any trees or shrubs on it, one thousand miles up the river
Missouri.  This mountain is one hundred and eighty miles long, and
forty-five miles wide.
   At Cordova, in the province of Catalonia in Spain, there is a moun-
tain of salt, between four and five hundred feet in height, and three
miles in circumference.
   * Salt springs, which abound in common salt, are found in the
North-Western Territory of the United States, near the lakes  in
Canada; upon the waters of the rivers Ohio, Kentucky, &c.
   Dr. Benjamin De Witt has given an account of the < 'nondaga salt
springs, which may be seen  in the Transactions of the Agricultural
 Society of New-York, vol. i. The strongest of these springs con-
 •ain about half a pound of salt to a gallon of water.—Am. Ed. 
        EXTRACTION OF SALT FROM  WATERS.    193

tributed with that  uniformity  as  to permit all nations to
have ready recourse to them, it has been found necessary
to extract the salt from the water of the sea.  The sea
does not contain an equal quantity in all climates :  Ingen-
housz has shewn us that  the northern  seas contain less
than die southern.  Marine salt is so abundant in Egypt,
that, according to Hasselquist,  a fresh-water spring is  a
treasure which is secretly transmitted  from father to son.
  The  method of extracting the  water of the sea varies
according to the climates.
  1. In the northern provinces, the salt sands of the sea
coasts are washed with the least possible quantity of wa-
ter, and the salt is obtained by evaporation.—See the de-
scription of this process by Mr. Guettard.
  2. In very cold countries, salt water is concentrated by
freezing,  and  the  residue is  evaporated by fire.—See
Wallerius.
   3. At the salt springs of Lorraine and  Franche-comte,
the water is pumped up,  and suffered to fall upon heaps
of  thorns, which divide it, and cause a part to evaporate.
The farther concentration is effected in boilers.
   4.  In the southern provinces, at Peccais, at Peyrat, at
Cette,   and elsewhere, the extraction is begun by separat-
ing a certain quantity of water from the  general mass of
the sea, which is  suffered to  remain in square  spaces,
called   Partenemens.   For this purpose it is necessary to
have sluices which may be opened and shut at pleasure,
and to form surrounding walls  which prevent all commu-
nication with the sea, except by means of these gates.  It
is in the partenemens that the water goes through the first
stage of  evaporation; and  when it begins to deposite its
salt, it is raised by bucket wheels to other square  com-
partments,  called Tables,  where the evaporation finishes.
   The salt is heaped together, to form  the  cammelles;
in which  state it is left for three years,  in order that the
deliquescent salts may flow out of it; and,  after this  in-
terval of  time,  it is carried to  market.
   Exertions and inquiries have long since been made to
discover  a cheap method of decomposing marine  salt, to
obtain  the mineral  alkali at a low price,  which is of such
 extensive use in the manufactures of soap,  glass,  bleach-
                          Bb 
I94t       DECOMPOSITION  OF SEA SALT.

ing, &c.  The processes hitherto discovered are the fol-
lowing;
   1. The nitric acid disengages the muriatic acid,  and
forms nitrate of soda, which may be easily decomposed
by detonation.
  2. Potash displaces the soda, even in the cold,  as I
found by experiment.
  3. The sulphuric acid forms  sulphate of soda by de-
composing the marine salt;  the new salt,  when  heated
with charcoal, is destroyed;  but a sulphure of soda,  or
liver of  sulphur, is formed, which is difficult to be en-
tirely separated ;  and this process does not appear to me
to be economical.   The sulphure  may  likewise be de-
composed by the aeetite of barytes, and the soda after-
wards obtained by calcination of the azetite of soda.
  4. Margraff tried in vain to  accomplish  this purpose,
by means of lime, serpentine, iron,  clay,  he.  He   adds,
that if common salt be thrown upon lead heated to red-
ness, the salt  is  decomposed, and  muriate  of lead  is
formed.
   5. Scheele has pointed out the oxides of lead for the
decomposition of common salt.   If  common salt be mix-
ed with litharge, and  made into a paste, the litharge gra-
dually loses  its  colour,  and becomes converted into a
white matter, from which the soda may be extracted by
washing.  It is by processes of this kind that Turner ex-
u-acts it in England;  but this  decomposition never ap-
peared to me to be complete, unless the litharge was em-
ployed in a proportion quadruple to that of the salt.   I
have observed that almost all bodies are capable of alka-
lizing marine salt, but that the absolute decomposition is
very difficult.
   6. Barytes decomposes it likewise, according to the ex-
periments of Bergmann.
   7. The vegetable acids, combined with lead,  may like-
wise be used to decompose common  salt.   When  these
salts are mixed,  a decomposition takes place : the  muri-
ate of lead falls down;  and the vegetable acid,  united to
the soda, remains in solution.   The vegetable  acid may
be  dissipated by evaporation and calcination; and the al-
kali remains disengaged. 
MURIATE OF  AMMONIAC.
195
   Marine salt is more especially employed at our tables,
and in culinary purposes.   It  removes and  corrects the
insipidity of our food, and at the same time facilitates di-
gestion.   It is used in a large proportion to preserve flesh
from putrefaction;  but in a small dose it hastens that pro-
cess,  according to  the experiments of Pringle, Macbride,
Gardane,  &c.


                    ARTICLE III.

                Muriate of Ammoniac.

   Of all the combinations of ammoniac this is  the most
interesting, and the most generally used.  It is known by
the name  of Sal Ammoniac.
   This salt may be directly formed by decomposing the
muriate of lime by the means of ammoniac, as Mr. Baume
has practised at Paris.   But almost all the sal ammo-
niac which circulates in commerce is brought to us from
Egypt, where it is extracted by distillation from soot, by
the combustion of the excrements of such animals as feed
on saiine plants.
   The details of the process which is used have not been
very long known.  One of the first writers who gave  a
description of this operation is father Sicard.   He inform-
ed us, in  1716,  that distilling vessels were charged  with
the soot of the excrements of oxen, to which sea salt and
camels urine were  added.
   Mr. Lemaire,  consul at Cairo, in a letter written to the
Academy  of Sciences in 1720,  affinns that  neither urine
nor sea salt are added.
   Mr. Hasselquist has communicated to the Academy of
Stockholm a  considerably extensive  description  of  the
process :  by  which we learn that die dung of all animals
which feed on saline plants is indiscriminately used, and
that the soot is distilled,  to obtain sal ammoniac.
   This dung is dried  by applying it  against the  walls :
and it is burned instead of wood,  in such countries as do
not possess that fuel.  The sublimation is performed  in
large round bottles of one foot and a  half diameter, ter-
minating in a neck of two inches in height; and they are 
196
EXTRACTION  OF SAL AMMONIAC.
 filled to within four inches of the neck.  The fire is kept
 up during three times twenty-four hours; the salt is sub-
 limed to the upper part of these vessels, where it forms a
 mass of the same figure as the vessels themselves.  Twen
 ty pounds of soot afford six pounds of sal ammoniac, ac-
 cording to Rudenskield.
   I was always of opinion that sal ammoniac might  be
 extracted by treating the dung of the  numerous animals
 which feed on saline plants in the plains of La Camargue
 and La Crau, in the same manner; and after having pro-
 cured,  with the greatest difficulty, two pounds of the
 soot,  I extracted from it four ounces of sal ammoniac.  I
 must observe,  to save much trouble  to those  who  may
 wish  to follow this branch of commerce, that the dung
 produced during the  summer, the spring, or the autumn,
 does  not afford this salt.   I did not know to what circum-
 stance to attribute the  versatility  of my  results,  until I
 found'that these animals do not eat saline vegetables, ex-
 cepting at the time when fresh plants cannot be had;  and
 that they are reduced to the necessity of having recourse
 to saline plants only during the three winter months.  This
 observation appears to me to be a proof, that marine salt
 is decomposed in the first passages;  and that the soda is
 modified to the state of ammoniac.
   Sal ammoniac is continually sublimed through the aper-
 tures  of volcanic mountains.   Mr. Ferber found it;  and
 Mr. Sage admitted its existence among volcanic products.
 It is found in the grottos of Puzzolo, according to Messrs.
 Swab, Scheffer, he.
   It is found in the  country of the  Calmucs.   Model
 analized it.
   It is also produced in the human body, and exhales  hy
 perspiration in malignant fevers.  Mr.  Model has  proved
 this fact in his own person : for at the  time of a  violent
 sweat  which terminated a malignant fever,  he washed his
hands in a solution of potash, and observed that a prodi-
 gious quantity of alkaline gas was disengaged.*

  * Leblanc de Franciade was the  author of a  process, for making
 sal ammoniac in France.  He covered the brick floor of an oven
heated to redness, with common salt, and  poured sulphuric acid
upon it.  The muriatic acid gas which arose  was  conducted by a
brick gutter, into a large leaden chamber, where it met with a stream 
NITRO-MURIATIC ACID.
197
   Sal ammoniac crystallizes  by evaporation in quadran-
gular pyramids.  It is often obtained in rhombic crystals
by sublimation.  The concave face of the loaves  of sal
ammoniac in commerce is sometimes covered with these
crystals.
   This salt has a  penetrating,  acrid, urinous taste.  It
possesses a degree of ductility which renders it  flexible,
and causes it to yield to a blow of the hammer.  It does
not change in the air; which circumstance renders it pro-
bable that our sal ammoniac is different from that  men-
tioned by Pliny and Agricola, as that attracted humidity.
Three parts and a half of water dissolve one part  of sal
ammoniac, at sixty degrees of Fahrenheit's thermometer:
a considerable degree of cold is produced by its solution.
   One hundred parts of sal  ammoniac contain fifty-two
parts acid, forty ammoniac, and eight water.
   This salt is not at all decomposed by clay;  nor by mag-
nesia except with difficulty,  and  in part only;  but it is
completely decomposed by lime and  fixed alkalis.   The
sulphuric and nitric acids disengage its acid.
   This salt is used in dying, to bring out certain colours.
It is mixed with aqua fortis, to increase its solvent power.
   It  is used in soldering, in wrhich operation it possesses
the double advantage of clearing the metallic surface, and
preventing its oxidation.
                     CHAPTER V.

          Concerning the Nitro-muriatic Acid,

     THE acid which we crll Nitro-muriatic, is a combi-
       nation of the nitric and muriatic acids.
  Our predecessors distinguished it by the name of Aqua
Regia, on account of its property of dissolving gold.

of ammoniacal gas, conducted thither from animal matters burning
at the same time, in three large iron cylinders, placed in a furnace
beside the former.   These gases condensed by mixture and formed
sal ammoniac—Am. Ed. 
198       - FORMATION OF AQJJA RECIA.

  There are several  known processes for making diis
mixed acid.
  If two ounces of common salt be distilled with four of
nitric acid, the acid which  comes over into the  receiver
will be good nitro-muriatic acid.
  This is the process of Mr. Baume.
  The nitrate of potash may be decomposed by distilling
two parts of muriatic acid from one  of this salt: good
aqua regia is the product of this operation; and  the resi-
due is a muriate of potash, according to Mr. Cornette.
  Boerhaave affirms that he obtained a good aqua  regia,
by  distilling a mixture of two parts of  nitre, three of sul-
phate of iron or martial vitriol, and five of common salt.
  The simple distillation of nitre  of the first boiling af-
fords aqua regia;  which is employed by the dyers in the
solution of tin,  for  the composition  of the scarlet dye.
This aqua fortis is a true aqua regia:  and it is by  virtue
of  the mixture of acids that it dissolves tin; for if it con-
sisted of the nitric acid in a state of too  great purity,  it
would corrode and oxide the metal without dissolving it.
The dyers then say that the aqua fortis  precipitates the
tin ; and they correct the acid by dissolving sal ammoniac
or  common salt in it.
   Four ounces of sal ammoniac in powder, dissolved gra-
dually, and in the cold, in one pound of nitric,  form an
excellent aqua regia.   An oxigenated  muriatic  acid gas
is disengaged for a long time; which  it  is imprudent to
attempt to coerce, and which ought to be suffered to  es-
cape by convenient apertures.
    Aqua regia is likewise formed by mixing together two
parts of pure nitric acid and one of muriatic acid.
    The very evident smell of oxigenated muriatic acid,
which is  disengaged  in every  process which can be a-
dopted to form the acid at present in question; and  the(
property  which it possesses, equally with the  oxigenated
 muriatic acid, of-dissolving gold, have led certain chemists
 to infer that, in the  mixture of these two acids, the muri-
 atic acid seized the oxigene of the nitric, and assumed the
 character  of oxigenated muriatic acid: so that  the nitric
 acid was considered as answering no other purpose than
 that of oxigenating the muriatic.  But this system is in-
 consistent; and though the virtues of the muriatic acid 
ACID OF BORAX.               199
are modified by this mixture, and it is oxided by the de-
composition of a portion  of the nitric acid, nevertheless
the two acids still exist in the aqua regia: and I am con-
vinced that the best made aqua regia, saturated with pot-
ash, will afford the ordinary muriate, the oxigenated mu-
riate, and the nitrate of potash.  It appears to me that the
powerful action of aqua regia, depends simply on the union
of the two acids; one of which is  exceedingly well calcu-
lated to oxide the metals,  and the other dissolves the ox-
ides or calces with the greatest avidity.
                   CHAPTER VI.


            Concerning the Acid of Borax.


     THE  acid  of borax,  more generally known by the
      name of Homberg's Sedative Salt, is almost always
afforded by the decomposition  of the borate of soda,  or
borax.  But it has been found perfectly*formed in certain
places; and we have reason to hope that we shall speedily
acquire more accurate information respecting its nature.
  Mr. Hoefer, director of the  Pharmacies of Tuscany,
was the first who detected this acid salt in the waters of
the lake Cherchiajo, near  Monte-Rotondo, in the inferior
province of Sienna:  these waters are very hot, and they
afforded him three ounces of the pure acid in one hun-
dred and twenty pounds of the water. This same chemist
having evaporated twelve thousand two hundred and eighty
grains of the water of the lake of Castelnuovo, obtained
one hundred and twenty grains.  He presumes, moreover,
that it might be found in the water of several other lakes,
such as those of Lasso, Monte-cerbeloni, &c.
  Mr. Sage has deposited in the hands of the Royal Aca-
demy of Sciences some acid of borax,  brought from the
mines of Tuscany by  Mr. Besson, who collected it him-
self. 
200
ACID OF BORAX.
   Mr. Westrumb found sedative salt in  the  stone called
 Cubic Quartz of  Luneburg.   He obtained it by decom-
 posing diis stone by the acids of sulphur, nitre, &c.  The
 result of his analysis is the following:

              Sedative salt
              Calcareous earth
              Magnesia
              Clay and silex  -
              Iron

   This stone, according to the observations of Lassius, has
 the form of small  cubical crystals, sometimes transparent,
 in other specimens milk}-, and  affords sparks with the
 steel.
   The acid of  borax is generally found combined with
 soda.   It  is  from this combination that it is disengaged,
 and obtained  either by sublimation or crystallization.
   When it is proposed to obtain it by sublimation,  three
 pounds of calcined sulphate of iron,  and two ounces of
 borate of soda are dissolved in three pounds of water. The
 solution is then  filtered,  and evaporated to a pellicle; af-
 ter which the  sublimation is performed in a  cucurbit of
 glass with  its  head.   The acid of borax attaches itself to
 the internal surface of the head,  from  which it  may be
 swept by a feather.
   Homberg obtained it by decomposing of borax with the
 sulphuric acid.  This process succeeded witii me wonder-
 fully wrell.  For this purpose I make use of a glass cucur-
 bit with  its head,  which I  place on a sand bath.  I then
 pour upon the borax half its weight of sulphuric acid, and
 proceed to sublimation.  The sublimed acid is of the most
 beautiful whiteness.
   Stahl, and Lemery the younger, obtained the same acid
 by making use of the nitric and muriatic  acids.
  To extract  the acid of borax by crystallization, the bo-
 rax is dissolved  in hot water, and an excess of sulphuric
acid is poured in.   A salt is deposited during the cooling
 on the side of the vessel, in the form of thin round plates,
 applied one upon the odier.   This salt when dry, is very
 white, very light, and  of a silvery appearance.   It is the
acid of borax.
  1
  i

TTTff 
ACID OF BORAX.
201
  We are indebted to Geoffrey for this process.  Baron
has added two facts:  the first, that the vegetable acids are
equally capable of  decomposing borax; and the second,
that borax may be regenerated by combining the acid of
borax with soda.
  This acid may  be purified by solution, filtration, and
evaporation:  but it must be observed, that a considerable
part is volatilized with the water which flies off in the eva-
poration.
  The acid of borax has  a saline cool taste.  It colours
the tincture of turnsol, sirup of violets, &c. red.
  One pound of boiling water dissolved no more than one
hundred and eighty-three  grains, according to Mr. De
Morveau.
  Alcohol dissolves it more easily; and the  flame which
this solution affords is  of  a beautiful green.  This acid,
when exposed to the fire,  is  reduced  to a vitriform and
transparent substance, instead of rising; which proves, as
Rouelle has observed, that it is only  sublimed by favour
of the water, with which it forms  a very  volatile  com-
pound.
   As  most of the* known acids decompose this acid, and
exhibit it in the same form, it has been thought a justifi-
able conclusion that it  exists ready formed in the borax.
Mr. Baume has even affirmed that he composed this acid
by  leaving a mixture of grey clay, grease, and cow's dung,
exposed to the air in a cellar.   But Mr. Wiegleb, after an
unsuccessful labour of three years and a half, thinks hip-  '
self authorized to give a formal negative  to the French
chemist.
   Mr. Cadet has endeavoured to prove—1. That the acid
of borax  always retains a portion of the acid employed in
the operation.  2.  That this same acid has still the mine-
ral  alkali  for its basis.  Mr.  De Morveau has, with  his
Visual sagacity, discussed  all  the proofs brought forward
by  Mr. Cadet;  he has shewn that none of  them are con-
clusive, and that the acid of  horax is entitled to retain its
place among the  chemical elements.*

  * By digesting oxigenated muriatic acid on the acid of borax for a
long time, Crell succeeded in decomposing it, and obtained from it a
substance  resembling charcoal in all its properties ; and a volatile
Cg 
202
BORATE OF SODA.
                       ARTICLE I.

                    Borate of Potash.

    The acid of  borax combined with potash forms this
  salt.   It may be obtained either by the direct combination
  of these two separate principles, or by decomposing borax
  by the addition of potash.
    This  salt,  which  is  yet  little known, afforded  Mr.
  Baume small crystals.
    The acids disengage it by seizing its alkaline base.


                       ARTICLE II.

                     Borate of Soda.

    This combination forms Borax, properly so called.
    It is brought to us from the Indies;  and its origin is
 still unknown.*
    The article Borax may be consulted in Bomare's Dic-
 tionary of Natural History.
    It does not appear that borax was known to  the anci-
 ents.  The chrysocolla, of which Dioscorides speaks, was
 nothing but an artificial  solder composed, by  the gold-
 smiths themselves,  with the urine of children and rust of
 copper, which were beaten together in a  mortar of the
 same metal.
   The word Borax is found for the first time in the works
'of Geber.  Every thing  which has been written since
 that time concerning borax, is applicable to the substance
 which is at present known to us by that name.

 acid resembling the muriatic, in the greater number of its properties,
 but differing from it, in not precipitating lead  from its solution.—
 Am. Ed. ,
   * The origin of borax is very well ascertained in two papers, in the
 seventy-seventh volume of the Philosophical Transactions, numbers
 xxviii and xxix.  It is dug up in a crystallized state from the bottom
 of certain salt lakes in a mountainous, barren, volcanic district, about
 twenty-five days journey to th# eastward of Lassa, the capital of the
 kingdom of Thibet.  T. 
       HISTORY AND PURIFICATION OF BORAX.  203

   Borax is found in commerce in three different states.—
   The first  is brute borax,  tincal, or  chrysocolla.   It
comes to us from  Persia, and is enveloped and soiled by
a  greasy  covering.   The pieces of brute borax have al-
most all of them the  form of  a  six-sided prism,  slightly
flattened,  and terminated by a dihedral  pyramid.  The
fracture of these crystals is brilliant, with a greenish cast
This kind of borax is very impure.  It is pretended that
borax  is extracted from the Lake of Necbal,  in the king-
dom of Grand Thibet.  This lake is filled  with water
during the winter,  which exhales in the summer; and
when the  waters are low workmen enter,  who detach the
crystals from the muddy bottom, and put them into bas-
kets.
   The West-Indies contain borax.   It is to Mr. Antony
Carera, a physician established at Potosi,  that we  are in-
debted for this discovery.  The  mines of Riquintipa, and
those in the neighbourhood of Escapa, afford this salt in
abundance.   The natives use  it  in the fusion of copper
ores.
   The second kind of borax known in commerce  comes
from China.   It is purer than the preceding, and has the
form of small plates  crystallized upon one of their sur-
faces,  on which the rudiments of prisms  may be perceiv-
ed.  This borax is mixed with  a white  powder,  which
appears to be of an argillaceous nature.
   These several  kinds  of borax have been purified at
Venice for a long time,  and afterwards in Holland; but
Messrs. Laguiller refine it at present in  Paris : and this
purified borax forms the third  kind which is met with in
commerce.
   In order to purify  borax, nothing  more is necessary
than to clear it of the unctuous substance which soils it,
and impedes its solution.
   Crude borax added to a solution of mineral alkali, is
more completely dissolved, and may be obtained of con-
siderable beauty  by a  first crystallization; but it  retains
the alkali made use of;  and borax, purified in this man-
ner,  possesses a greater portion of alkali than in its crude
state. 
204
THE PROPERTIES  AND
   The oily part of borax may be  destroyed bv  calcina-
tion.  .By this  treatment it becomes  more soluble, and
may in fact be purified in this  wav.  But the method is
attended with a considerable loss, and is not so advanta-
geous as might be imagined.
   The most  simple method of purifving borax,  consists
m boiling it strongly,  and for a long time.   This solution"
being filtrated,  affords by evaporation crystals rather foul,
which may be purified by a second operation  similar to
the foregoing.  I have tried all these processes in die hirge
way ; and the latter appeared to me to be the  most  sim-
ple.*
   Purified borax  is white,  transparent,  and has a some-
what greasy  appearance  in its fracture.
   It crystallizes in hexahedral prisms, terminated by tri-
hedral and sometimes hexahedral pyramids.
   It has a styptic taste.
   It converts blue vegetable colours to  a green.
   When borax is exposed to the  fire,  it swells up, the
water of crystallization is dissipated in  the  form of va-
pour ;  and the salt then  becomes converted into a porous,
light, white,  and opake mass, commonly called Calcined
Borax.   If the fire be more strongly urged, it  assumes
a pasty  appearance, and is at length fused into a  transpa-
rent glass of a greenish  yellow colour,  soluble in water;
and which loses its transparency by exposure to the air,
in consequence of a white efflorescence  that forms  upon
its surface.
   This salt requires eighteen times its  weight of water,
at the temperature of sixty degrees of  Fahrenheit's ther-
mometer,  to dissolve it.  Boiling-water  dissolves one-
sixth of its weight.f

  * Nalmont Bomare informs us, that the Dutch extract eighty parts
of pure borax, from  one hundred of tincal.  The operations are con-
ducted in leaden vessels, and consist chiefly in repeated solutions, fil-
trations, and crystallizations.  He suspects that they employ lime-
water, and Fourcroy has shewn, that this might be useful in decom-
posing the soap in which crude borax is  enveloped.—Am. Ed.
  t When two pieces of borax are struck together in the dark) a flash
of light is emitted.—Am.  Ed. 
HABITUDES  OF
BORAX.
205
  Barytes and magnesia decompose  borax.  Lime-water
precipitates the solution of this salt;  and if quick-lime be
boiled with borax, a salt of sparing  solubility is  formed,
wliich is the borate of lime.
  Borax is used as an excellent flux in docimastic opera-
tions.  It enters into the composition of  reducing fluxes,
and is of the greatest use in analyses by the blow-pipe. It
may be applied  with advantage in  glass manufactories;
for when the fusion turns out bad, a small quantity of bo-
rax re-establishes it.   It is more especially used in  sol-
dering.  It assists the fusion of the solder,  causes it to
flow,  and  keeps the surface of the metals  in a soft or
clean state, which facilitates the operation.   It is scarcely
of any use in medicine.  Sedative salt alone  is  used  by
some physicians;  and  its name sufficiently  indicates its
application.
   Borax has the inconvenience of swelling  up,  and  re-
quires  the greatest attention on the  part  of the artist who
uses  it in delicate works,  more especially when designs
are formed with gold of different colours.  It has  been
long a desideratum to substitute some composition in the
room of borax, which might possess its advantages with-
out its defects.
   Mr. Georgi has published the following process :—
" Natron, mixed with marine salt and Glauber's salt, is
to be dissolved  in lime-water;  and the crystals which  se-
parate by the cooling of the fluid may be set apart.  The
lixivium of natron is then to be evaporated;  and this salt
afterwards dissolved in milk.  The  evaporation affords
scarcely one eighth of the natron employed,  and the resi-
due may be applied to the same uses as borax."
   Messrs. Struve and Exchaquet  have proved  that  the
phosphate of potash, fused with a certain quantity of sul-
phate of lime, forms an excellent glass for soldering  me-
tals.—See the Journal de Physique, t. xxix, p. 78, 79. 
206
BORATE QF  AMMONIAC
                     ARTICLE  III.

                 Borate of Ammoniac.

   This salt is still little known.   We are indebted to Mr.
De Fourcroy for the following indications:—He dissolved
the acid of borax in ammoniac, and  obtained by evapo-
ration a bed or plate of crystals connected together, whose
surface exhibited polyhedral pyramids.   This salt  has a
penetrating and urinous taste; it  renders blue vegetable
flowers green;  gradually  loses its crystalline form,  and
becomes of a brown colour,  by the contact of air.  It
appears to be of  considerable solubility in water.  Lime
disengages the volatile alkali. 
PART THE SECOND.
Concerning Lithology;  or, an  Account of Stony
                  Substances.
INTRODUCTION.
     THE object of Lithology consists in the study of stones
       and earths.
   It is generally agreed to call those substances  by the
name of Earth or Stone, which are dry, brittle, inodorous,
insipid, scarcely or not at all soluble in water, and of a
specific gravity not exceeding 4,5.
   There is no one who has seriously attended to the study
of lithology, without being at the same time aware of the
necessity of establishing  divisions to facilitate the  know-
ledge of stones, and to remove the numberless difficulties
which would otherwise oppose the acquisition of that know-
ledge.
   It is an obvious difference between living creatures and
the subjects of the mineral kingdom, that these last are
continually modified by external causes, such as air, water,
fire, &c. while the former, being animated and governed
by an internal force, possess characters of a more definite
and unchangeable nature.  The forms of these  depend
upon their organization;  and, in  general, the proceedings
of nature respecting them are more constant, and better
ascertained.
   The earthy element appears to be passive  of itself;  it
is obedient only to the laws of inanimate bodies;  and we
may refer all the phenomena of formation or decomposi- 
208
ON THE CLASSIFICATION
tion, which a stone is susceptible of, to the mere law of
affinities.  This, no doubt, is the cause of  that variety of
forms, and that mixture of principles, which scarcely per-
mit the naturalist to establish his system upon fixed bases,
or to found it upon constant and invariable  characters.
   If we take a view  of the proceedings of all the natural-
ists who have hitherto written, we may easily reduce them
to three classes.
   1. The first class, carried by the imagination alone to
that epocha when this globe issued from the hands of the
Creator, have  followed the actions of the various destruc-
tive agents which alter or overturn its surface.  In this
way they have shewn us the  various  rocks successively
deposited or placed upon  the  primitive globe;  and, by
surveying the great phenomena wliich have happened up-
on our planet,  they have acquired ideas more or less accu-
rate respecting the vast works of decomposition and for-
mation.
  2. Others have busied themselves in inquiring, by ana-
lysis, what are the earths or primitive matters out of which
all the stones we are  acquainted with are composed. This
class of philosophers  have supplied us with  the most valu-
able acquisitions respecting die nature, the uses,  and the
decompositions of these  substances:  but  the  results  of
analysis, though necessary in acquiring accurate notions
of each stone, are not of themselves sufficient to form the
basis of a method of classing;  because these  characters
are too difficult to be acquired, and at most can be used
only as supplementary in the establishment of such other
methods as may be employed.
   3.   Almost all the  systems  of classification hitherto
adopted,  are  founded upon the external characters  of
earthy substances.
   Some naturalists have sought,  in the variety of  forms
exhibited by the productions of the mineral kingdom, such
principles of division as to them appeared sufficient.   But
not to mention that the same form  frequently  obtains in
very different stones, this character is rarely found, and we
are ignorant of the  crystallization of most of the known
earths: the crystallization cannot therefore be considered
but as an accessary or secondary circumstance. 
OF EARTHS AND STONES.          2Q9
   Other naturalists have established dieir divisions upon
certain properties easy to be ascertained, such  as  that of
effervescing with acids, giving fire with the steel, &c.  But
these characters do not appear to be sufficiently strict, nor
sufficiently exclusive;  for  nothing is more common than
to find a mixture of the fragments of primitive rock's with
those of calcareous  stones.  Our province exhibits ex-
amples of this every step we take;  and these  mixtures,
hardened by time, possess both  the fore-mentioned cha-
racters.  There are also stones which,  without changing
their nature, give fire with the  steel, or effervesce  with
acids,  accordingly as they  are  more  or less divided.
Such is the lapis lazuli, which effervesces when pulverized,
but strikes fire when in the mass; the slate likewise effer-
vesces when in powder, but not in the mass.  The classi-
fication, therefore, which is founded on these characters,
is not rigorous, and may at the most be made  use of in
conjunction with others.
   M. D'Aubenton is the naturalist  wtio appears to me to
have distributed mineral substances  with the greatest or-
der of any who has hitherto undertaken that task;  every
thing which he  says on this subject, shews the experi-
enced eye of the observer;  and he has drawn from the ex-
ternal characters of bodies all the characters possible to be
had from that source.  But he could not avoid the defects
which necessarily accompany the  principles on  which he
has founded his system.
   Deeply impressed with a sense of the  insufficiency of
these methods, as well as of the slight opportunities I have
possessed of improving them, my endeavours  have been
exerted in collecting together all the characters which are
capable of affording any useful indications.  In this pur-
suit, I have joined the characters of the naturalist to those
of the chemist;  and though the method which I have adopt-
ed be very far from that degree of perfection which might
be desired, I nevertheless present  it to the public with con-
fidence.  It differs but little from  that followed by Messrs.
Bergmann and  Kirwan; a circumstance which at least af-
fords a prejudice in its favour.  The  peculiar advantages
which, in my opinion,  it appears to possess, are—1.  The
lithologic productions are  distributed equally, and into
three classes. 2. All the analogous productions are brought
                        Dd 
210       CLASSIFICATION OF EARTHS, &C.

together, and arranged as it were in a natural order.   In
a word,  this system  has fixed my own ideas in the most
precise  manner;  and  this has more particularly  induced
me to propose it to the public*
   The various earths beneath our feet arer in general, com-
binations; and chemists, by decomposing these substances,
have succeeded in obtaining, in the last analysis, principles
which may be considered as earthy elements, until sub-
sequent  acquisitions shall either confirm  or destroy our
ideas on this subject.
   The earthy elements most extensively distributed are ten
in number;  namely, Lime, Magnesia, Barytes, Strontites,
Alumine, Silex, Yttria, Glucina, Zirconia,  and Agustina.
   Nature appears to have formed  all the mixtures and
combinations which constitute stones,  out of the primitive
earths here spoken of.
   If we direct our attention to the nature  of these mix-
tures and combinations,  we  shall distinguish  three habi-

  * I consider what is here published respecting Lithology as a sim-
ple and short  sketch of the principles which I explain in my Lec-
tures.  It would be judging me with too much severity, if the reader
were to suppose that my present design is to exhibit a complete per-
formance.
  A more intimate acquaintance with this subject may be obtained
by the perusal of the following works :
   1. Essai d'un Art de Fusion, a l'Aide de l'Air Vital, par Erhmann.
Memoires de M. Lavoisier sur le meme sujet—Memoires de  M.
D'Arcet,  sur l'Action d'un Feu egal, violent, et continu, sur un grand
nombre de Terres, Pierres, Sec.
  2. The works of Margraff and Pott, more especially the Lithoge-
ognesia of the latter.
  3. Les Pesanteurs Sp£cifiques des Corps, par M. Brisson.
  4. Elements of Mineralogy, by Mr. Kirwan.
  5. Le Manuel du Mineralogiste de Bergmann, enrichi de Notes
par JVI. L'Abbe Mongez.
  6. La Mimralogie de M. Sage.
  7. Les Ouvrages sur laCrystallographie de M. Rome de Lisle, de
M- l'abbe Hauy, &c.
  8. Le Tableau Methodiqoe des Minereaux, par M. D'Aubenton.
  9. La Mineralogie de M. le Comte de Buffon ;  in which that cele-
brated writer has collected a great number of valuable facts, whose
merit is independent of all theory.
   10. The Mineralogical  Works of Messrs, Jars, Dietrich, de Born,
Ferber, Trebra, Pallas, Gmelin, Linne, Dolomieu de Saussure de la
Peyrouse, &c.
   11. The excellent Analyses of Stones, published from time to time
by  Pott,  Margraff,  Bayen,  Bergmann, Gerard, Scheele,  Achard,
Mongez,  &c. 
LIME,  OR  CALCAREOUS EARTH.
tudes or modes, which establish three grand divisions.
We shall immediately perceive that these earths are, in
some instances, combined with acids, which form  saline
stones; that in other instances they  are mixed with  each
other,  and form  stones  properly  so called;  and that in
other instances, again,  these  stones, so formed by the
mixture of primitive earths, are united together, or fixed
in a gluten or cement,  which forms rocks, pebbles, or
compound stones.                            e
   We shall therefore distinguish three classes in Litholo-
gy i the first will comprehend saline stones;  the second
stones,  properly so called, or  earthy mixtures; and the
third rocks,  or stony admixtures.
   We  consider it  as  indispensably necessary to explain
the nature of the primitive earths, before we can proceed
to treat of their combinations.


                        I. Lime.

   This earth has been found totally disengaged from all
 combination, near Bath.—See Falconer on the Bath Wa-
 ters, vol. i. p.  156 and 157.   But as this  is  perhaps the
 only observation of the kind which we possess,  it  is in-
 dispensably necessary to shew the process by which lime
 may be obtained in a state of  the greatest purity.
   For diis purpose chalk  is to be washed in boiling dis-
 tilled water, then dissolved indistilled acetous acid,  and
 precipitated by the carbonate of ammoniac,  or  mild vo-
 latile alkali  The precipitate, being washed and calcined,
 is pure lime.
   This earth possesses the following characters :
   1. It is soluble  in six  hundred  and eighty  times its
 weight of water, at the temperature of sixty degrees of
 Fahrenheit.  Kirwan.
   2. It has a penetrating, acrid,  and burning taste.
   3. Its specific gravity is about 2,3  according to Kir-
 wan, and 2,720 according to Bergmann.
   4. It seizes water with great avidity;  at the same time
 that it falls into  powder,  increases in bulk, and emits
 heat 
212              MAGNESIAN EARTH.
  5.  Acids dissolve it  without effervescence,  but with
the production of heat.
  6. The borate of  soda, or borax, the oxides  of lead,
and the phosphates of urine, dissolve it by the blow-pipe
without effervescence.
  It appears to be infusible alone, as it  has resisted the
heat of flame urged  by  a stream of vital air.—See the
Memoir of Mr. Lavoisier.
  When it is mixed with acids,  it forms a  fusible  com-
bination ; and it hastens the fusion of aluminous,  silice-
ous, and magnesian  earths,  according to the experiments
of  Messrs. Darcet and Berermann.
            II. Magnesia,  or Magnesian Earth.

  This earth has been no where  found disengaged  from
all foreign substances ; but in order to obtain it in the ut-
most possible state of purity, the crystals of the  sulphate
of magnesia, or Epsom salt,  are to be dissolved in  dis-
tilled  water, and decomposed by  the carbonate of  al-
kali.   The precipitate must then be calcined, to disen-
gage the carbonic acid.
  1. Pure magnesia is very white,  very friable,  and, as
it were, spongy.
  2. Its specific  gravity is about 2,33, according to Kir-
wan.
  3. It is not perceptibly soluble  in  water when pure;
but when it is combined with the carbonic acid,  it is so-
luble ;  and cold water has a stronger action on it than hot,
according to the experiments of Mr. Butini.
  4. It has no perceptible action on the tongue.
  5.   It slightly  converts the tincture of  turnsol to a
green.
  6. Mr. Darcet has observed, that a strong heat agglu.
tinates it more or less ; but Messrs. De Morveau, Butini
and Kirwan, found that it was not fusible;  and the expe-
riments of  Mr. Lavoisier have proved that it is as infusi-
ble as  barytes and lime.
  The borate of soda, and the phosphates of urine,  dis-
solve it with effervescence.—See the abbe  Mongez. 
BARYTES,  OR  PONDEROUS EARTH.
21$
             III. Barytes, or Ponderous Earth.

  We are  indebted  to the celebrated  chemists Gahn,
Scheele,  and Bergmann, for our knowledge of this earth.
  It has  not yet been found exempted from all combina-
tion ; but in order to  obtain it in a suitable degree of pu-
rity, the following process may be used:
  The sulphate of  barytes, or ponderous spar, wliich
is the most  usual combination met with on  the  earth, is
to be pulverized, and calcined in  a  crucible,  with  an
eighth part of powder of charcoal:  the crucible must be
kept ignited during an hour; after which the  calcined
matter is to be thrown into water : it communicates a yel-
low colour to this fluid, at the  same time that  a strong
smell of hepatic gas is emitted; the water is  then to  be
filtred, and  muriatic acid poured in : a considerable pre-
cipitate falls down, which must be separated from the
fluid by  filtration.   The water wliich passes through the
filtre holds  the muriate of  barytes,  or  marine  salt of pon-
derous earth,  in solution.   The carbonate  of potash, or
mild vegetable alkali, in solution, being then added, the
ponderous earth falls down, in combination with  the car-
bonic acid; and this  last principle may be driven off by
calcination.
   1.  Pure barytes is of a pulverulent form, and extreme-
ly white.
   2.  It is soluble in about nine hundred times its weight
of  distilled  water, at  the  temperature of sixty  degreesj
according to Kirwan.
   3.  The Prussiate of potash, or Prussian alkali, preci-
pitates it from its combination with the nitric  and muria-
tic acids.  This habitude distinguishes it from other earths.
—See Kirwan.
   4.  It precipitates alkalis from their  combinations with
acids.
   5.  Barytes exposed, by  Mr. Lavoisier, to flame fed
with oxigenous gas, was fused in a few seconds : it ex-
tended itself upon the surface of the coal; after which it
began to burn and detonate  until  the whole  was nearly
dissipated.   This kind of inflammation is a character com- 
214                   S1R0NTIIES.
mon to metallic substances; but when the barytes is pure
it is perfectiy infusible.—See Lavoisier.
   Ponderous earth urged by the  blow-pipe  makes little
effervescence with soda, but is perceptibly diminished :  it
dissolves in the borate of soda with effervescence, and still
more with the phosphates of urine.—See the abbe  Mon-
gez'  Manuel du Mineralogists
   6.  Its specific gravity exceeds 4,000, according to Kir-
wan.*
                        * IV. Strontites.

  This mineral is  met  with  in the lead mine of Strontian in Ar-
gyleshirc, where it is found mixed with a variety of substances.  It
is united to the carbonic acid, forming carbonate of strontites.
  It specific gravity varies from 3.4 to 3.726.
  Its texture is generally fibrous,  and sometimes it is found crystal-
lized, in slender prismatic columns of various lengths.
  The carbonic acid may be separated from the carbonate of stron-
tites, and the strontian obtained in a pure state, by mixing the mi-
neral with powder of charcoal, and  exposing the  mixture to a high
degree of heat;  or  the mineral may be dissolved in the nitric acid,
the solution evaporated until it crystallizes, and the crystals exposed
in a crucible to a red heat till the nitric acid is driven off.
  Pure strontites has a caustic taste, it changes blue  vegetable co-
Jours green, and  unites  oil with water.  It attracts carbonic acid,
from the atmosphere. When water is poured on strontites, it slacks,
becomes hot, and falls into powder.  One hundred  and sixty-two
parts of water, at the temperature of 60°, dissolve nearly  one part
of strontites.   It  combines with sulphur and phosphorus.  It is not
a poison to animals.
  It tinges the flame of combustible bodies of a red colour.   This
experiment is performed, by moistening  the nitrate  of  muriate of
strontites with alcohol, in a silver spoon, setting fire to the mixture,
and holding it when burning over the flame of a candle,  in order to
cause a quick and rapid combustion.
  Many of the  European  mineralogists  inform  us,  that  sulphate
of strontites is found at Frankstown in Pennsylvania.   Klaproth ana-
lized a specimen from this  place.   He found its specific, gravity to
be 3.830.   Its colour is a pale sky blue.   It occurs in flat layers or
strata  from \, ^ to -| of an  inch  thick, included  between two
even sides ; which last partly appear to be real seams or joints, and
partly are mere separating surfaces, formed  by small  clefts  of the
rock, filled with clay.  On these exterior sides, the fossil has a dull
appearance, but internally it is possessed  of the ordinary lustre.  It
is easily communicated, and consists ^throughout  of coarse parallel
brittle fibres,  which_form needle shaped fragments. 
ALUMINE, OR PURE  CLAY.
215
                V. Alumine, or Pure Clay.

  This earth is not more exempt from mixture and com-
bination than  the foregoing;  and in order to obtain it in
a state of purity,  the sulphate of alumine is dissolved in
water, and decomposed by effervescent alkalis.
  1.  Pure clay seizes water with avidity, and may then
be kneaded.   It adheres strongly to the tongue.
  2.  Its specific gravity does not exceed 2,000, according
to Kirwan.
  3.  When exposed to heat, it dries,  contracts,  shrinks,
and  becomes full of clefts.  A considerable degree of
heat renders it so hard that it gives fire with the steel.
  When it has been well baked, it is  no longer capable
of uniting with water; but requires to be dissolved in an
acid, and precipitated, in order that it may resume this
property.
   The experiments of Mr. Lavoisier  shew that pure alu-
mine is capable of an imperfect fusion, approaching to
the consistence of paste,  by  heat excited by a current of
vital  air.   It is then transformed into a kind of very hard
stone,  which cuts glass like  the precious  stones,  and
which very difficultly yields to the file.
   The mixture of chalk singularly assists  the fusion of
this earth : it is fusible in a crucible of chalk, according
to Mr. Gerhard,  but not in a crucible of clay.
   The borate of soda, and the phosphates of lime, dissolve
it.—See Kirwan and the abbe Mongez.
   According to the experiments of Mr. Dorthes, the pu-
rest native clays, and even that which  is precipitated from
alum, contain a small quantity of iron in the state of oxide;
and it is from this principle that the earthy smell which is

  One hundred parts of this blue fibrous sulphated strontianite, con-
tain*
       Strontian earth                      58
       Sulphuric acid                      42
       And a slight trace of oxided  iron

                                        100
   Strontites may be obtained pure,  from this sulphate, by following
 the process described for procuring barytes,  in a state of purity.—
 Am. E<f.
   • Klaproth's Analytical Essays, p. 394» 
216       SILEX, OR VITRIFIABLE EARTH.
emitted by moistened clays, arises; it  is  very difficult to
deprive them of it.


     VI. Silex, or Quartzose Earth, Vitrifiable Earth, &c.

  This earth exists nearly in a state of purity in rock crys-
tal.  But when it is required to be had in a state of  pu-
rity free from all suspicion, one part of fine rock crystal
may be fused with four of pure alkali.  The fused mass
must then be dissolved in water,  and  precipitated by an
excess of acid.
   1. Pure silex possesses a singular degree of roughness
and asperity to the touch.   It is absolutely void of all dis-
position to adhere; and its particles, when agitated in wa-
ter, fall down with extreme facility.
   2.  Its specific gravity is 2,65.
   3.  Bergmann had affirmed that water might dissolve it;
and Mr. Kirwan has pretended that 10,000 parts of water
might hold one of silex in solution, at the ordinary tempe-
rature of the atmosphere; and might even take up a great-
er quantity at a higher temperature.
   The fluoric acid dissolves it;  and lets  it fall when  it
comes in contact with water, or  when it is considerably
cooled.
   5. Alkalis dissolve it in the dry way, and form  glass;
but they attack it likewise  in  humid way, and are  ca-
pable of dissolving one-sixth part of their weight when it
is in a state of extreme division.
   6. The burning mirror does not fuse it; but a current
of vital air produced a  commencement  of fusion on its
surface.—See Lavoisier.
   Before the blow-pipe  soda  dissolves it with efferves-
cence.   The borate of soda dissolves it slowly, and with-
out ebullition.*

                       •VII. Yttria.
   This mineral is found in the quarry of Ytterby, in Sweden.  It  is
 the heaviest of the earths.  Its specific gravity is 4.84 3.  It has nei-
 ther taste nor smell.  It is infusible by heat, but vitrifies with borax.
 It is insoluble in water, and has no action on blue vegetable colours.
 It dissolves in carbonate of ammonia., but is insoluble in the pure al-
 kalis. It combines with the acids, and may be precipitated from them, 
G LUC IK A.
217
                           CLASS L

   Concerning the Combination of Earths with Acids.


   This class, which comprehends the combination of pri-
 mitive earths with acids, naturally exhibits five genera.

 by ammoniac, the prussiate of potash,  and  tannin.  Its other pro-
 perties have not been examined.

                        VIII.  Glucina.
   We are  indebted to the celebrated Vauquelin, for the knowledge
 of this earth, who discovered it in the year 1795, in the emerald and
 and beryl.   It is found combined with silex, lime, alumine and oxide
 of iron.  The word glucina is derived from the Greek yKun.uSi wliich
 signifies sweet, as it gives this taste to the salts it forms.
   In order to obtain glucina, the beryl or emerald must be reduced to
 an impalpable powder, and melted with three times its weight of pot-
 ash, and the mass dissolved in marine  acid diluted with water, and
 the solution evaporated to dryness.  The residuum is then to be mixed
 with  a great quantity of water, and the whole thrown upon a filtre.
 The silex which constitutes more than  half the weight of the stone,
 remains behind: but the glucina and other earths, being combined
 with muriatic acid, remain in solution.   Precipitate them by a solu-
 tion of the potash of the shop.  Wash the precipitate in distilled wa-
 ter, and dissolve it in sulphuric acid.  Add to the solution sulphate of
 potash : evaporate ft to the proper consistency, and set it aside to crys-
 tallize.   Crystals of alum will be gradually formed. When as many
 of these as possible have been obtained, pour into the liquid carbonate
 •of ammoniac in excess, then filtre,  and  boil the liquid for some time.
 A white powder will appear, which is glucina.
   Glucina is of a white colour, and soft to the touch, without either
 taste or smell.   It adheres strongly to the tongue.  It has no effect
 on vegetable  colours.  It cannot be melted by means of heat.  It
 ■does not contract its dimensions like alumine.  It is soluble in liquid
 potash and soda, and insoluble in ammoniac, but soluble in carbonate
 of ammoniac: it combines with the acids, and forms with them salts
 of a saccharine taste.  Its specific gravity is 2.967.

                         IX.  Zirconia.
   We are indebted to the celebrated Klaproth for the discovery  of
this earth.  It is found in a precious stone, called Zircon or Jargon.
 This  gem  was first brought from the island of Ceylon, but has also
 been met with in France, Spain,  and other parts of  Europe.   Its co-
 lour is various,  as grey,  greenish-white, yellowish, reddish brown  or
 purple,  and violet.   Accum says it has little lustre, and is  nearly
 opaque, whereas Thomson informs us, it has a good deal of lustre, and
 is mostly semi-transparent.   Its specific gravity is from 4.416 to 4.7,
 according to Kirwan.
                              Ee 
218
ACUSTINA.
                          GENUS  I.

            Earthy Salts with Basis of Lime.

   The combination of lime with various acids affords the
several species of calcareous  salts  comprehended in this
genus.

  Zircon earth possesses a very white colour, is exceedingly heavy,
and harsh to the touch like  silex ; it is insoluble in water, but forms
with it a jelly ; it is destitute of taste and  odour.   It melts with
borax  into  a transparent  colourless  glass.    It undergoes a kind
of imperfect fusion, when heated violently in a charcoal crucible, ac-
quiring a grey colour, and something of the appearance of porcelain.
In this state it is very hard, its specific gravity is 4.3, and it is insolu-
ble in acids.  It is insoluble in water,  but has a considerable affinity
for that liquid.   When dried slowly, after being precipitated from a
solution, it retains about one-third of its weight of water, and assumes
a yellow colour, and a certain degree of transparency, which gives it
a great resemblance to gum arabic.
  It will not combine with oxigene, simple combustibles, nor metals.
It has a strong affinity for several metallic oxides, particularly for the
oxide of iron, from which it cannot be easily separated.
  It is insoluble, even by boiling, in liquid alkalis, neither can it be
fused with them by means of heat, but it is soluble in alkaline carbo-
nates.  We know not its affinity for the different earths.  A mixture
of alumine and zirconia is capable of fusion.  It is of no use in medi-
cine or the arts.
  Zirconia is obtained in the following manner :  Reduce the jargon
to powder, mix it with three times its weight of potash, and fuse it in
a crucible.   Wash the obtained mass in distilled water, till the whole
of the potash be extracted; then dissolve the residuum as far as pos-
sible in diluted muriatic acid.   Boil the solution to precipitate any si-
lex it  may contain, filtre it, and gradually add a  solution of potash.
The zirconia will precipitate in the  form of a fine  white powder,
which  must be repeatedly washed in distilled water, and dried.

                          X.  jigustina.

  This earth is found in the Beryl of Saxony, and is so called,because
it has  the property of forming salts,, which are nearly destitute of
taste.
  The properties of Agustina, according to Tromsdorff, are,
  First. It is white and insipid, and when pure resembles alumine.
  Secondly.  It combines  with acids, and forms with  them salts,
which  have little or no taste.
  Thirdly.  It does not combine either in the  humid  or dry way,
with alkalis or their carbonates.
  Fourthly. It retains carbonic acid but feebly ;  and,
  Fifthly. It is insoluble in water.—Am. Ed. 
CARBONATES OF LIME.
219
                       SPECIES I.

        Carbonate of Lime, or Calcareous Stone.

   The combination of lime with the carbonic acid is very
 commonly met with, and comprehends all the stones which
 have hitherto been distinguished under the names of lime-
 stone, calcareous stone, he.
   The characters of the carbonates of lime are—1. They
 effervesce with certain acids.  2. They are  converted in-
 to lime by calcination.
   The formation of these stones appears  to us to be, for
 the most part, owing to the wearing down of shells.   The
 identity of the constituent principles of shells and calcare-
 ous stones, and the presence of these same shells, more or
 less altered,  in the lime-stone mountains, authorize us to
 conclude that a great part at least of the calcareous mass
 of our globe owes its origin to this cause only.
   Though our imagination  appears to assent with diffi-
 culty in referring effects of so wonderfully extensive a na-
 ture to a  cause apparently so weak, we are  compelled to
 admit it when we take a slight view of the known history
 of shells.
   In fact, we observe the numerous class of shell animals
 which possess this stony covering almost at the instant of
 their origin.   We see it insensibly become thick and en-
 larged by the apposition of new coverings: and this shell
 at length comes to occupy a volume fifty or sixty times
 larger than that of the animal which produced it.   Let us
 consider the prodigious number of animals which emit
 this stony transudation;  let us attend to their speedy aug-
 mentation, their multiplication, and the  short period of
their life, the  mean term of which is about ten years,  ac-
cording to the calculation  of the celebrated Buffon; let us
 multiply the number of these animals by the mass of shell
they leave behind them—and we shall then arrive at  the
mass which the shells of one single generation ought to
form upon this globe.  If we proceed further to consider
how many generations are  extinct, and how many species 
220
CALCAREOUS  SPAR.
are lost, we shall be no longer surprized to find that a con-
siderable part of the surface of the globe is covered with
their remains.
   It may easily be conceived that these shells, when car-
ried along by currents of watery must strike together, and
wear their respective surfaces,;  and that their pulverulent
remains,, after being long, carried about  and suspended
by the waters,, must at last subside,  and form heaps  or
rSanks of shells, more or less altered according to circum-
stances.
   But whatever may be admitted as  the  origin of this
stone,  it is found to exist in twro principal states; that is
to say, either  in the form  of crystals, or of  irregular
masses.
             I. Cryftallized Calcareous Stones,

  A  concurrence of circumstances which very seldom
meet together, is required, in order that crystallization may
take place.  This is, doubtless, the reason why spars and
calcareous crystals compose the smallest part of this genus.
These crystals are found in the cavities  of calcareous
mountains;  in the clefts which penetrate into the internal
part of stones  of this class;  and  generally in all places
where waters find access,  after having worn down calca-
reous stone to a state of extreme attenuation, nearly cor-
respondent to solution.
  Calcareous stone,  in its  crystallized state,, presents  us
with several varieties of form; but the rhomboidal figure
appears to be the most  constant and  the  most  general.
The environs of Alais abound with rhomboidal spars  of
the greatest  beauty; they are transparent like those  of
Iceland,  and double objects in the same manner.
  It often happens that a  group of rhomboidal crystals
exhibits at its surface a number of pyramids more or less
prominent, which consist of the angles of rhomboids  of
different degrees of length.   It cannot but be admitted,
with Mr.  Rome de Lisle, that the  pyramidal  form  is a
slight modification of the rhomboid; for if a pyramid  of
spar be broken, it is reduced into  elements of a rhom-
boidal figure. 
CALCAREOUS STONES.
221
  The principal varieties of the pyramidal form  are  de-
duced more especially from the number  of their sides;
and when the pyramid is long and sharp, it is called dog-
tooth spar, or hog-tooth spar.
  Calcareous stones often affect the prismatic form; and
this is likewise attended with some varieties.
  The prism is frequently six-sided and truncated; some-
times it is terminated by a trihedral  pyramid;  and when
the prism is very short, and its summit is almost  entirely
in contact  with the  ground, the crystal is known by the
name of Lenticular Spar.
  All the varieties of form which crystallized calcareous
stones have hitherto presented,  may be seen in the Crys-
tallography of Mr. Rome de Lisle.
  The specific gravity of calcareous spars is about 2.700
when pure, according to Kirwan.
  They contain from thirty-four to thirty-six parts of car-
bonic acid, and from fifty-three to  fifty-five of earth;  the
rest is water.—See Kirwan.
  Spars  often exhibit a smooth uniform  surface, upon
which the sulphuric acid takes  but slight hold : they  are
sometimes contaminated with iron, which gives them va
rious tinges.
       II. Calcareous stones which are not crystallized.

   Few calcareous stones affect any regular form: they
lie almost always in strata, or immense blocks thrown or
heaped together on the surface of the globe, in which we
cannot reasonably pretend to discern any primitive  design
of crystallization.  The notion itself which we have of the
formation of these mountains, and the stratified disposition
of their parts, does not allow us to discern any other effect
than the natural consequence  of the flowing  of  water,
which  must have occasioned a  contraction,  and disposed
the rocks in strata or beds.
   It seems to me that two  very natural divisions may be
established among calcareous stones which are not crystal-
lized :  for they are either susceptible of a perfect  polish, 
222        CALCAREOUS STONES.  MARBLE.
 in which case they  are called marbles and alabasters r or
 they are not susceptible of this polish, in which case they
 are called friable earths, tufa,  &c.
   A.  Calcareous stones susceptible of a perfect polish.
   Although it be  proved from  the experiments of che-
 mists,  and more especially from those of Mr. Bayen, that
 marbles contain a greater  or less proportion of clay, we
 are under  the necessity  of placing them here;  because
 the calcareous earth predominates to such a degree, that
 they cannot with propriety be placed elsewhere;  and be-
 cause they possess all the  characters of lime-stone.
   Marbles differ from other calcareous stones by the  po-
 lish of which they are susceptible; and  they  are distin-
 guished from each other by their colours.
   White marble is usually the purest.  We  are acquaint-
 ed  with the  marble of Carrara,  and  the ancient  statuary
 marble of  Paros.
   Black marble is coloured either by a bitumen or by
 iron.   Mr. Bayen found this metal in the  proportion of
 five parts in the hundred.    When it is veined by pyrites,
 it is called Portor.
   There  are an infinite number of varieties of coloured
 marble.  The colouring part is  in general owing to the
 alterations  of the iron, which sometimes is obedient  to
 the magnet, according to an observation of Mr. De Lisle.
 Blue and green marbles owe their colours to a mixture of
 schorle, according to Rinmann ^n his History of Iron.
  The marble which  presents the figure of  shells ap-
 pears to be formed simply out of a  heap of shells con-
 nected by a calcareous cement;  it is known  by the name
 of Lumachello.  That of  Bleyberg in Carinthia forms one
 of the most beautiful species.
  The marble which is called figured  marble, exhibits ei-
 ther traces of vegetables,  as that of Hesse;  or ruins and
rocks, like that of Florence.   The dendrites appear to be
formed merely  by  ferruginous infiltrations  through the
 cracks  of these stones.
  Several naturalists have mentioned flexible marble. Fa-
 ther Jacquier described this in  1764, in the Gazette Litte-
raire; and  the abbe De Sauvages  has commimicated, to 
CALCAREOUS STONES.  MARBLE.
223
the Aademy of Montpellier a description of the plates of
flexible marble which are in the Palais Bourgeois.
   Alabasters are calcareous stones of the nature of marble;
they appear to be formed like the stalactites, and are some-
times adorned with the most beautiful colours:  these i \
general possess a certain transparency, with a stratiform
texture variously coloured, and cause  a double refraction
of the light when they are sufficiently transparent.   In he
treatise of Mr. Brisson on the specific  gravities of bodies,
the reader will find the result of his valuable experiments
on that of marbles, alabasters, and generally all the calca-
reous stones.
   B. Calcareous stone not susceptible of a perfect polish.
   Calcareous stones which are not suceptible of a perfect
polish,  are found either in masses,  or in the pulverulent
form; which circumstance will afford a foundation for our
natural distinction.
   1.  Solid calcareous stone is in general the stone used for
building; and  this  is found in several varieties, differing
in fineness of grain, porosity, colour, consistence, or weight.
These are gradations which establish the  several qualities
of stones; and are the cause why one hardens in the air,
while another is decomposed.   On these  several accounts
it is that  the respective varieties  are  applied  to  various
uses; and it is the business of the skilful artist who uses
them to distinguish their qualities.
   In the number of these stones  used for building, there
are some which imbibe and retain water,  in  consequence
of which they are burst or crumbled by the frost;  whereas
others suffer the water which they originally  contained to
escape, and become  harder by the contact of the air.
   2.  Calcareous  stone is sometimes found in the pulve-
rulent form.  Chalk is of this kind; and  when it is  white
and very finely divided, it is formed  into  those  masses
known  in commerce by  the  name  of  Spanish White.
For  this  purpose it is agitated in  a  vessel with water.
The foreign substances, such as  flints, pyrites, &c. are
precipitated; the water is then decanted;  and the chalk,
which is held suspended,  very soon subsides: this is dri-
ed, and divided into long square pieces,  to form die Spa-
nish White. 
224             CALCAREOUS STONES.
  When a natural stream of water wears away this chalk,
and afterwards deposites it, the result has been distinguish-
ed by the name of Gurrh ; and when this possesses a cer-
tain consistence, arising from the mixture of argillaceous
and magnesian earths,  it is distinguished by the name of
Agaric Mineral.
  As calcareous earth is susceptible of extreme  division,
the water  which wears it away,  and is afterwards filtred
through  the  clefts  in rocks, deposites it gradually,  and
forms those  incrustations known by the vulgar under the.
name of  Petrifactions, and  by  that of Stalactites  among
naturalists.
  These calcareous depositions very frequently  preserve
the form of such substances  as  they have covered, and
present figures of moss, roots, fruit, &c. which  has gi-
ven rise to an opinion that those substances  wrere trans-
formed into stone.
  The increase of stalactites being accomplished  by ad-
dition to  their external surfaces, their  texture exhibits
concentric coats of different shades, accordingly  as the
water may have been  charged with  different colouring
principles.
  The cavities which are frequently found in calcareous
mountains are often lined with stalactites; and these grot-
tos form one of the most striking appearances which can
present itself to the eyes of the naturalist
  The grandeur of these subterraneous places, the absence
of light, the  feeble  glimmering of  a  torch, which  only
half enlightens the surrounding objects,  render these re-
gions gloom)', majestic, and imposing.  The multiplicity
of figures, the variety  of forms,  and their  resemblance
to other objects, never fail to cause a high degree of asto-
nishment in the mind of the mineralogical student   A-
mong the infinite number of these forms, there are some
which are very agreeable, such as the flos ferri, cauliflow-
ers,  lace, or fringes.  Other  very singular figures are
likewise  found,  such as the priapolithes, pisolithes, oo-
lithes, &c.
   Mr. Lougeon of Ganges has  observed, in the grotto
called Des Demoiselles, a number of forms so varied and
strange,  as to exhibit a very astonishing collection. 
CALCAREOUS STONES.             225
  These transudations, or rather these stony depositions,
have given rise  to  a belief in the vegetation of stones.
The celebrated Tournefort was of opinion that he  had
observed nature in the very fact, in the famous  grotto  of
Antiparos,  where  he saw inscriptions engraved in the
stone,  but afterwards converted into reliefs.  Baglivi has
written a treatise on the vegetation of stones, in which he
cites many facts of this nature.
  All the world is acquainted with the depositions of the
spring in the vicinity of Clermont; but the most surpris-
ing of  all  petrifying waters is that of Guancavelica  in
Peru.   Barba, D.  UUoa,  and Frezier, have given  us a
description of it.  Feuille informs us that this water rises
very hot in the  middle of  a square bason, and becomes
petrified at a small distance from the spring.  The water
is of a yellowish white, and the  incrustations have been
used to build the houses  of Guancavelica.   The work-
men fill moulds with its water,  and some days afterwards
they find them  incrusted with this stone.  The statuaries
expose their moulds in this spring, and have only to give
the polish in order  to render their statues transparent.  All
the statues used in religious ceremonies,  by the  catholics
of Lima, are of this substance, and  are  very  beautiful.
—Journal des Observ. torn. i. 434.                    ,
   In the  year  1760,  Mr.  Vegni devised  a method of
making a similar use of the very white  chalk  which is
contained in the waters of the baths of St. Philip in Tus-
cany.   For this purpose the water is suffered  to  run for
the space  of near a mile, in order that it may deposite die
sulphur,  the selenite, and the tufa which it contains ;  and
in this  purified  state it is used in the fabrication of bas re-
liefs.   It is  introduced at  the  roof of a building, into a
closet constructed of planks fitted together.  The  water
falls from twelve to fifteen feet in height, upon a wooden
cross placed on a post;  by which fall  it is  divided,  and
dashes laterally against sulphur moulds, which are placed
 on the sides of the cabinet.  In this way it deposites the
 particles of the earth which it contained,  and the mould
 becomes filled.   Mr. Vigni placed the moulds upon pieces
 of wood which are moved circularly.   This alabaster is
 as hard as marble ; and the incrustation is more beautiful,
                           Ff 
226            CALCAREOUS  STOYES.
 and harder, in proportion as the position of the mould  is
 more vertical,  and its distance greater.


        The Analysis and Uses of Calcareous Stone.

   In 1755, Dr. Black proved that  calcareous stone pos-
 sesses,  as one of its component parts, an air different from
 atmospheric air.  He asserted that  calcareous stone when
 deprived of this air by calcination,  forms lime ; and  that
 lime might again pass to the state of calcareous stone  by
 resuming the principle it had been deprived of.  In 1764,
 Macbride supported this doctrine by new facts.   Jacquin
 added other experiments to these ;  and  proved that lime
 and alkalis owe their causticity to the subtraction of this
 fixed air, at the same time that he pointed out several
 methods of depriving them of it.
   The  processes which are most commonly used for the
 decomposition  of lime-stone, are fire and acids;  the first
 is used in the making of lime ; the second in laboratories,
 when it is intended to procure the carbonic acid.
   In order to form lime, the calcareous stone is  calcined
 in furnaces, whose construction is varied according to the
 nature of the combustibles made use of.
   When pit-coal is used, an inverted cone is constructed
 of •vitrifiable stone, which  is filled  by alternate strata of
 coal and lime-stone ;  and the lime is taken out, after the
 operation,  by an aperture  at the top.   In  proportion as
 the mass subsides,  care is  taken to  supply the furnace at
 the top, in  order that  the flame and heat may not be lost.
   Bergmann has observed that most specimens of calca-
 reous stone which become  black or brown by calcination,
 contain manganese, and that the lime which they  produce
 is excellent.
   According to Rinmann, the white calcareous stones
 which become black by calcination, contain about one tenth
 part of  this substance.
  Calcination deprives lime-stone of the acid and water
 which it contained.   These two  principles  are evidently
 replaced by the matter of heat itself.  The odour of fire
which -quick-lime emits ; the light which it affords when
 slackened in a dark place r the colour which it communi- 
FABRICATION OE  LIME.           $$2,7
•cates to the lapis causticus; the property which it  pos-
 sesses of producing the oxide and  the glasses of lead—
.all prove to us, as Mr. Darcet observes in the Journal de
 Physique for 1783, tiiat  in proportion as the calcareous
 stone is deprived of the aeriform  principle, it combines
 with the igneous principle, wiiich cannot be displaced but
 by the way  of affinities.   The beautiful experiments of
 Meyer,  when divested of all theory, prove the same tiling.
    It is  proved, from the experiments  of Dr.  Higgins,
 that the  best lime is that which is  made with the hardest
 and most compact stone broken  into small pieces,  and
 heated slowly, until the furnace is  become of a white lieat
 This heat must be kept up until the stone  is no longer
 capable of effervescing with acids.   The  lime  becomes
 overturned if the ignition be carried to a greater degree;
 and the produce is then a frit, which is no longer capable
 of being divided  in  water, or of resuming  with avidity
 the principles it had lost.
    When pieces of calcareous stone of different sizes are
 calcined, the lime will not all be of equal  goodness ; the
 small pieces consisting of over-burned lime, while the
 larger pieces are scarcely altered in their central parts.
    The  best lime is that which is the most quickly  divid-
 ed by immersion in water, and affords the greatest quan-
 tity of  heat in this process, which causes it to fall into the
 finest powder.  Good lime should likewise dissolve in the
 acetous acid without effervescence^ and leave the  least
 possible quantity of  residue.
     Lime continually  endeavours to resume the acid and
  the water of which the stone was deprived by calcination:
 consequently, when it is left exposed to the air, it cracks,
 becomes heated,  falls into powder  with  an increase  of
  bulk, and  resumes  the property of effervescing.   It  is
  therefore of importance to use  lime newly  made,  if the
  artist be desirous of possessing its whole force.
     Lime is sparingly soluble in water, and this solution is
  called lime-water; the lime may  be precipitated by means
  of carbonic acid, which regenerates calcareous stone in
  the form of a precipitate.
     tLime-wrater  is used to indicate the presence, and deter-
  mine the proportion, O.f .carbonic  acid an any .mineral w ai. 
^28           LIME-WATER .AND LIME.
   Physicians prescribe it as an absorbent and detergent.
   When lime-water is left in contact with the air of the
atmosphere, a pellicle is formed at its surface, known  by
the name of the cream of lime; this is the regenerated
calcareous stone.
   The superb bason of  Lampi,  one of the two principal
reservoirs which furnish the Royal  Canal  of Languedoc
with  water, was  found to  leak  at  the junction of the
stones.  The  skilfui  engineer  who  directs these works,
Mr. Pin, caused lime to  be  slacked; which, passing
through these small apertures, became supplied with car-
bonic acid, and formed a crust, or very white  covering,
over its whole surface: so that all the stones of this fine
piece of masonry are connected together by this cement;
and at present constitute one single undivided  substance,
impenetrable to water.
   The regeneration of calcareous stone is very slowly  ef-
fected by the processes hitherto described.   But this may
be expedited by presenting to the lime the principles with
which it so strongly tends to combine :  this is according-
ly done in works in the large way.
   Lime is usually slacked by pouring abundance  of wa-
ter upon it.  A violent heat is thus excited ;  the lime falls
down into powder,  and a paste is  afforded by strongly
working the lime together in proportion as it becomes  sa-
turated.
   The count Razoumouski has taken advantage of  the
heat which is disengaged when lime  is  slacked, to com-
bine the lime with sulphur.
   The degree of heat proper to effect this combination is
70 of Reaumur.   At this  point the sulphur,  which  is
placed in contact with the lime, liquefies,  becomes of a
red colour, and forms a true sulphure or hepar of lime.
   Mortar is made simply by working sand, or other bo-
dies insoluble in water, together with slacked lime.
   We are acquainted with two kinds of sand at Mont-
pellier ; pit sand, and river sand :  the former is almost al-
ways altered by a mixture of vegetable and calcareous
earth, which weakens its efficacy;  the second is purer,
and better suited for  the purpose.   Instead of  sand,  the
fragments or dust of stone may be used : the angles which 
MORTAR OF  THE
ANCIENTS.
229
these fragments present,  and the roughness  of their sur-
face, contribute to give a consistence to the  mortar.
  The hardening of mortars appears to be owing merely
to the progressive regeneration of lime-stone.  They do
not obtain the greatest degree of  hardness of which they
are  susceptible, until they have resumed all  the carbonic
acid of which the stone was deprived : and  this operation
is very slow, unless the combustion be facilitated by well-
known methods, which consist in mixing substances with
the mortar which contain either the  carbonic acid, or  a
principle analogous to it, such as vinegar.
  It is this regeneration of lime-stone, which is  effected
by the lapse of time, that explains to us why the hardest
stones afford the best lime ; and why old mortars are
found to possess a degree of  hardness which modern ar-
tists have no hopes of attaining.
  The remains of ancient buildings have induced certain
philosophers to conclude, that the ancients  were in pos-
session of very valuable processes for the making of mor-
tar.   Mr. De la Faye was of opinion,  that  those enor-
mous masses, in which the perfection of the mechanical
processes of the ancients only was admired,  were  made
by coffer work ;  and he imagined that he had discovered,
in Vitruvius,  Pliny,  and Saint Augustin, that their pro-
cess to extinguish lime differed from ours;  and that the
great difference which appears to exist between the anci-
ent and modern mortars depends  more particularly upon
this  circumstance.   These interesting researches have in-
duced him to propose that the lime should be put  into  a
basket, and suffered to slack in the air;  as  he thinks by
this means it would preserve  a greater  degree of  force,
and  be less weakened than by the usual processes.
  Loriot has attributed the superiority of the mortars of
the ancients to the means which  they used  to dry them
speedily; and in  consequence of  these principles he mix-
es pounded bricks with flints, works the whole together
with slacked lime,  and  dries the mass with one-fourth
part of quick-lime.   Care must be taken to  use only lime
which is finely pulverized and sifted; for  otherwise the
mortar would crack,  and be very  imperfect.
  Nature sometimes presents to us a suitable mixture of
lime-stone and sand,  to form an excellent mortar without 
230
PLASTER  STONE.
any mixture of extraneous substances.  Mr. De Morveau
found this lime-stone in Burgundy ;  Mr. De  Puymaurin
has described a species which he found in  Berne ; and I
have observed in Cevennes a natural mixture of this kind,
in which the proportion of materials was so well assorted,
that nothing more was necessary'  than to  calcine it, and
extinguish it in water, to form an excellent mortar.*
                        SPECIES II.

    Sulphate of Lime, Gypsum, Selenite, Plaster Stone.

   The Plaster Stone loses its transparency by calcination;
at the same time that it becomes pulverulent, and acquires
the property of again seizing the water of which it  had
been deprived,  and  resuming its  hardness;  it does  not
give fire with the steel, nor effervesce with acids.
   We are more particularly indebted to Margraff for our
acquaintance with the constituent principles of plaster;
and from subsequent experiments  the following propor-
tion of the same principles has been assigned.   One hun-
dred parts of gypsum contain thirty sulphuric acid, thir-
ty-two pure earth,  thirty-eight water;  it  loses nearly
twenty per cent, by  calcination.
   We begin to be equally acquainted widi the formation
of this stone.   The chevalier De Lamanon  has asserted,
that the numerous quarries of plaster which are found  in

   * Only one vein of lime-stone is known below the blue ridge in
 Virginia.   Its first appearance is in the county of Prince Willi-
 am, two miles below the Pignut rklge  of mountains, and is never
 more than one hundred yards wide.  Lime-stone  is found  on the
 Mississippi and Ohio,  and in all the mountainous country between
 the eastern and western waters, occupying the valleys between the
 mountains.*
   Dr. Mitchell informs us  that there is  a mass of it eight hundred
 acres in extent, near Claverack, New-York, which is remarkable for
 its petrifactions.
   In travelling; from Albany to the Ballstown springs, and from thence
 through the Genesee country to the falls of  Niagara, rocks of lime-
 stone  are every where  met with, covered with the impressions of
 shells.
   It is also found in  immense quantities in  Pennsylvania, Maryland.
 North-Carolina, and  Massachusetts.—Am. Ed.
   "* Jefferson's Notes on Virginia,  p. i*. 
FORMATION  OF C?FSUM.
231
the \ icinity of Paris, are the deposition of an ancient flu-
viatile  lake, formed by  the Seine,  Loise,  and  Manic,
which  flowed off on the side of Meulan.  The  wrought
iron, and the various remains of animals which are found
at the bottom of the quarries of Mont Matre, shew that
its formation is  not very ancient; and the  indefatigable
naturalist here  cited considers the selenite  as originally
dispersed in the  water, precipitated in consequence of its
sparing solubility,  and heaped  together in places deter-
mined by currents, waves, and other circumstances.
  These facts highly interesting as they are in the natural
history of plaster,  are insufficient for the chemist  who is
desirous of knowing likewise in what manner, and under
what   circumstances,  the combination of  the sulphuric
acid and lime is made.   I shall proceed to communicate
some'observations which our province affords.
   1. I have observed in a black and pyritaceous  clay  of
Saint Sauveur, extracted out of the work called Perce -
ment Dillon, many small needle-formed crystals  of  sele-
nite, from four to eight lines in length.  At the  surface
of the  soil where the same clay is more decomposed, cry-
stals of the same nature, but longer,  thicker, and more
numerous, are also found.
  2. The marly and pyritous clay of Caunelle, near Mos-
son, abounds with beautiful  crystals of rose-coloured
plaster, in the form of cocks'  combs,  observed  by  Mr.
Dorthes.
   3. The plaster quarry of La Salle exhibits almost al-
ternately strata of  plaster and strata of black and pyritous
clay,  which effloresces in the air.
   4. Near the  bridge of Herepian, on the  declivity  of
Cascastel, at Gabian, and in many other  places,  I  have
constantly found crystals of gypsum  mixed and confound-
ed with pyritaceous clays.
   5. The sulphureous depositions of solfatara often con-
tain crystals of selenite.
   From these facts it appears to me  that the formation of
gypsum may easily be conceived.  It  is not formed ex-
cepting in places where pyrites and clay more or less cal-
careous are found  together: that is to say,  its formation 
232            FORMATION OF  GYPSUM.
appears to be dependant on, and connected with, the pre-
sence of sulphur and lime.*
   Whenever, therefore, the  pyrites is decomposed, the
sulphuric acid which thence arises  seizes the  lime, and
effloresces in small crystals, wiiich are carried off by the
water, and sooner  or  later deposited.   I have  observed
perceptible depositions of plaster on the banks of rivulets
which wash pyritous clays.  I have likewise  seen depo-
sitions of the same nature in rivers  whose waters have
been strongly concentrated by the  burning heat of our
summer.   And consequently, if we  suppose  selenite  to
be dispersed in more considerable masses of w ater, there
will be no difficulty in conceiving the  formation  of those
strata which the plaster quarries exhibit.
   Messrs. De Cazozy and Macquart  have  observed the
transition of the gypsum of Cracovia to the state of cal-
cedony.   When the nucleus of calcedony is determined,
it increases perceptibly in  the course of time,  even in ca-
binets;  which proves that the quartzose juice, when once
infiltrated into plaster, combines  with the lime,  and de-
termines  this transformation.
   Mr.  Dorthes  has proved  that the quartz, in  cocks'
combs  at Passy, owed its origin to plaster; that this last
substance having been carried away  by solution, the quart-
zose juice has taken its place.   Natural history  exhibits
several  of these metamorphoses.
   Gypsum is found in the earth in  four different states.
   1.  In the pulverulent and  friable form, which  consti-
tutes gypseous earth,  fossil flour, &c.
   2.  In solid masses,  which constitute plaster stone.
   3.  In stalactites, or secondary  depositions.   In this
place we  may  arrange the striated  silky gypsums, the
cauliflowers,  the gypseous alabasters,  and that prodigious
variety  of forms wiiich the stalactites assume, whatever
may be its component parts.

  * It is formed in this manner, at the falls of Niagara.  Sulphur
of a white colour is found  adhering to the sides of the great rocks,
at this place, and there is a spring, emitting sulphurated hydrogene
gas, within a mile of the falls.
   The rocks consist of a species of calcareous earth,  called  the
swine stone, and when small pieces of them are rubbed together,
they emit a strong  hepatic smell—Am. Ed. 
HABITUDES OF  GYPSUM.           233
  4. In determinate crystals, which usually exhibit  the
following forms.
  1. The compressed tetrahedral rhomboidal prism.
  2. The hexahedral prism truncated at its summit.
  3. The decahedral rhomboid.  I apprehend  that  the
lenticular gypsum may be referred to this last form, as it
appears to me to  be composed  of several rhomboids
united together side-ways.   At all  events I  have,  as  the
last result,  obtained the rhomboidal form,  by decompos-
ing this variety.
  The colour of  gypsum is subject to a great number of
varieties, which are the signs of various qualities relative
to its uses.  The white is the most beautiful, but some-
times it is grey;  and in this case  is less  esteemed,  and
less valuable.
  The several states of the oxides of iron, with which it
abounds in greater or less quantities, constitute  its rose-
coloured,  red, black,  &c.  varieties.
  The specific gravity of gypsum varies according to its
purity.—See Messrs. Brisson and Kirwan: the latter found
it sometimes of the weight of 2.32,  and sometimes 1.87.
  It is soluble in about five hundred times its weight of
water, at the temperature of 60 degrees of Fahrenheit.
  When it is exposed to heat,  its  water of crystallization
is dissipated, it becomes opake, loses its consistence,  and
falls into powder.   If it  be moistened,  it becomes hard
again,  but does not resume its transparency; a circum-
stance which appears to prove that its first state is a state
of crystallization.
  If it be kept in a fire of considerable  intensity, in con-
tact with  powder of charcoal,  the acid is  decomposed,
and the residue is lime.
  Its principles may likewise be separated by finely pul-
verizing it,  and boiling it with  alkali.
  It is fusible by the blow-pipe according to Bergmann;
and in a porcelain furnace, according to Darcet
  The management of the fire in the calcination of gyp-
sum is of great consequence.   Too much  heat  decom-
poses it; and too little does not enable it  to  unite,  and
form a hard substance with water.
  Calcined gypsum divides and disperses itself in water,
with which it forms a paste that may be cast into every
                         Gg 
234
FLUATE OF  LIME, OR  FLUOR  SPAR.
figure imaginable.   We are indebted to this property for
beautiful ornaments in the inside of our  houses;  but it
cannot be used for external decorations, because its solu-
bility in water renders it gradually destructible by that li-
quid.*
                     SPECIES III.

Eluate  of Lime, Vitreous Spar, Fusible or Phosphoric
                   Spar, Fluor Spar.

  This stone is a combination of a peculiar acid, called
the fluor acid, widi lime.
  It decrepitates on heated coals, like muriate of soda, or
common salt.   When  slightiy heated, it shines with a
beautiful blue  colour,  that remains even under water, or
in acids.   The residue of this appearance of combustion
is white and opake.
  Its specific gravity is, in general, from 3.14 to 3.18, ac-
cording to Kirwan.
  This spar enters into fusion by a strong heat, and cor-
rodes the crucible:  it likewise fuses without effervescence
with the mineral alkali, the borate of soda, and  the phos-
phates of urine.
  This stone possesses the most lively  and various co-
lours;  and it is known  under  the names of false emerald,
false amethyst, or false topaz, accordingly as its colour is
green, violet, or yellow.
  The  blue fluor spars commonly owe their colour to
iron, but sometimes to cobalt.  Berlin Berchaft, torn. ii.
p. 330.—Green fluors  are coloured by iron, according to
Rinmann.   The most usual form of fluate of  lime is the
cubic, with all the modifications which  accompany this
primitive form.
  * There is but little gypsum in the United States.  It is found of
a very white colour, imbedded in rocks of swine stone, at the falls
of Niagara,  and has absurdly been called the spray of the falls.
  It is said to have been discovered in the state of New-York, on
the nine mile creek, or outlet of the Owasco lake, and at the falls
of the Genesee river, and in Virginia, upon one of the head waters
of the Staunton,  about twenty-five miles from Fincastle.t—Am. Ed.
  t Barton's Phys. and Med. Journal, vol. i. 
PROPERTIES OF THE ACID OF FLUOR.
235
   When this stone is distilled with its own weight of sul-
phuric acid, the first product consists of elastic whitish va-
pours, which fill the receiver, and deposite  a crust at the
surface of the water, while the water itself becomes acidu-
lous.   The residue in  the  retort is sulphate of lime, ac-
cording to Scheele.   The crust which is formed on the
water of the receiver is siliceous earth;  and the water it-
self being saturated with the vapour, constitutes the fluoric
acid.
   The most astonishing property of this acid is doubtless
that of seizing the siliceous earth, which is a constituent
principle of the glass, and volatilizing it with itself.
   In order to have the acid in a  state of  greater purity,
and exempt from every mixture  of silex,  the  operations
are performed in retorts of  lead;  but Mr. De Puymaurin
is convinced, as well as myself, that the acid even then is
seldom pure, because the most beautiful fluor contains al-
most always a small  quantity of silex, which the acid car-
ries with it.  The whitest, the most transparent, and the
 most  regularly-crystallized fluor, distilled  on  the  water
bath in a leaden retort,  afforded me an acid contaminated
 by a small quantity of silex.
    Mr. Meyer having used every possible means to obtain
 this acid in a state of great purity, is convinced that when
 the acid does  not find silex in the retort, it attacks the
 sides of the receiver, and becomes changed.
    This acid may be preserved in bottles whose internal
 surfaces are coated with wax dissolved in oil.
    The fluoric acid has some analogy with the muriatic,
 and some-chemists have even confounded them together:
 but they differ essentially from each other.
    The  fluoric acid—1. When combined with potash,
 presents a gelatinous substance, which when dry retains
 one-fifth of the alkali employed, and forms a true neutral
 salt.  2.  It acts nearly in  the same manner with soda.  3.
 With ammoniac it affords  a jelly,  which when dry exhi-
 bits all the  appearances of silex.  4. When  mixed with
 lime water,  it regenerates the fluate of lime.  5. It does
 not attack gold, nor dissolve silver; and combines in pre-
 ference with oxides, such as those of lead, iron, copper,
 tin, cobalt, and even of silver. 
236     PROPERTIES OF THE ACID  OF FLUOR.

   One part of the fluate of lime, fused with four parts of
caustic fixed alkali, forms a salt insoluble in water.   The
same quantity of fluate of lime, treated in the same man-
ner with the carbonate of potash, or mild vegetable alkali,
affords a soluble salt; and  at  the  bottom of the water a
calcareous earth  is  found,  which proves that the fluoric
acid is not separated but by double affinity.
   This stone, which hitherto  has  not been employed but
as a flux, or in the  fabrication of  ornaments, appears to
me to deserve the most particular attention.  Its texture
seems to be lamellated like the diamond;   and  like that
stone it is capable of double refraction, as the abbe Ro-
chon has observed.   Its phosphorescence has likewise
some relation with the combustibility of the diamond, and
it has lively and varied colours.  All these circumstances
establish an analogy between  these two substances; and
might lead us to suspect that the constituent principles of
the diamond exist in this stone, mixed and combined with
an acid and lime, &c.
   The fluoric acid possesses the very singular property of
attacking glass, and dissolving and carrying off  its silice-
ous part.   Margraff  first observed this  property;  but
Messrs.  De Puymaurin and Klaproth have  very happily
applied it to the art of engraving on glass.
   This acid is employed to corrode the glass, in the same
manner as aqua fortis is used  to engrave upon copper.
   Some authors, particularly  Mr. Monnet,  have endea-
voured to prove that this acid was nothing else but a mo-
dification of the acid used in the decomposition of the spar.
They seem to found their opinion chiefly on the circum-
stance, that the acid obtained exceeds in weight the spar
made use of;  but  they have neglected  the increase of
weight which must arise from the erosion, dissolution, and
mixture  of the glass of the distilling vessels.  And indeed
these experiments do not appear to me to invalidate in the
least the  eternal truths which have issued from the labora-
tory of the celebrated Scheele; otherwise such modifica-
tions in the acids employed, would in my opinion afford a
phenomenon still more astonishing than the existence of
this peculiar acid.*

  * Fluoric acid has been found in  the enamel of the human teeth
and in ivory by Marechini and Guy Lussac.   It is a remarkable fact, 
-VITRATE OF LIME.
237
                     SPECIES IV.

          Nitrate of Lime, Calcareous Nitre.

  This salt, as well as those which remain to be treated of
in the present genus, exists only  in waters.   Their great
solubility, and their spontaneous deliquescence, do not per-
mit them to form durable masses, or to exist in the  form
of stones.
  The nitrate of lime is principally formed near inhabited
places;  old plaster affords it in abundance by lixiviation.
It is one of the  salts which abound  in the modier waters
of the salt-petre makers;  and  it has been found in some
mineral waters.
  It is usually obtained in the  form of small needles, ap-
plied sideways to each other.
  When a solution of nitrate of lime is  concentrated to  a
gelatinous consistence nearly  equal  to  that  of syrup,  it
forms, in process of time, crystals in  hexahedral prisms.
Two parts of cold water dissolve one of this salt; and boil-
ing water dissolves more than  its own weight.
  Its taste is bitter and disagreeable.
  It liquefies  easily on the fire, and becomes solid by cool-
ing: if it be strongly calcined,  and carried into the dark,
it is luminous, and constitutes  Baldwin's phosphorus.
  It loses its acid in a violent and continued heat.   When
distilled in close  vessels, it affords the same products as ni-
tre by the decomposition of its  acid.
  Projected upon ignited coals, it detonates in proportion
as it becomes dry.   See De Fourcroy.
  Its acid may be disengaged  by means of clay and of die
sulphuric acid.
  The alkalis and barytes precipitate its earth.
  The sulphuric salts, and die carbonates of alkali, decom-
pose it by double affinity.

that as in the teeth, the fluoric acid  occurs  n combination with the
phosphoric acid, the phosphate of lime, brought from Estremadura
contains likewise fluate of lime.—Am. Ed. 
238
CALCAREOUS PHOSPHORIC SALT.
                      SPECIES V.

      Muriate of Lime,  Calcareous Marine Salt.

   This combination exists more especially in the  waters
of the sea; and contributes to  give  to these waters that
bitter taste which has improperly been referred to bitu-
mens that have no existence.
   This salt is very deliquescent;  one part and  a half of
water dissolves one of this salt; and hot water dissolves
more than its own weight.
   It may be made to crystallize by concentrating its solu-
tion to the 45th degree of Baume, and exposing it after-
wards in a cool place.
   With these precautions it  affords  a salt in tetrahedral
prisms terminated by four-sided pyramids.—See De Four-
croy.
   It enters into fusion with a moderate heat; but  is de-
composed with great difficulty.   It acquires by calcination
the property of shining in the dark, and is called the phos-
phorus of Homberg.
   It is decomposed by barytes  and the alkalis.  The con-
centrated sulphuric1 acid, poured upon a very strong solu-
tion of  muriate of lime, disengages the acid in vapours,
and forms a solid precipitate; an appearance which seems
in an instant to transform two liquids into a solid, and pro-
duces a very striking effect.  The theory  of this pheno-
menon is easily deduced from the very great solubility  of
the muriate, and the almost  absolute insolubility  of the
sulphate which takes its place.


                      SPECIES VI.

    Phosphate of Lime, Calcareous  Phosphoric Salt.

   This  phosphate of lime has been found in Spain, in the
kingdom of Estremadura, by Mr. Bowie.
   It is  a  whitish stone of considerable density, not hard
enough  to  give fife with the steel.  It is found in horizon- 
PONDEROUS SPAR.
239
tal strata, reposing upon  quartz, and exhibiting vertical,
flattened, and close fibres.  When thrown on ignited coals,
it  does not decrepitate,  but burns quietly, and affords a
beautiful green light, which seems to penetrate through it,
and does not disappear so quickly but that a sufficient time
is admitted to contemplate  its brilliancy with admiration.
Before the blow-pipe it runs into a white enamel, without
boiling up; whereas bones support the most violent heat
without fusion.   Its habitudes with the nitric and sulphu-
ric acids are the same as  those of calcined bones; its acid
may be separated and brought into the state of an  animal
glass; it may be decomposed, and  the phosphorus  ex-
tracted.
   Mr. Proust, from whom we borrow these interesting
details, observes likewise that this stone is found to com-
pose the mass of entire hills in the neighbourhood of  the
village of Logrosan, in the jurisdiction of Truxillo, a pro-
vince of Estremadura. The houses and the walls of inclo-
sures are built of it.
                      GENUS II.

         Earthy Salts with Base of Barytes.

  The most common state in which Barytes is found is in
combination with the sulphuric acid.


                      SPECIES I.

        Sulphate of Barytes, Ponderous Spar.

  This stone is the most ponderous we are acquainted
with.   Its specific gravity is commonly from  4 to 4.6.
  It decrepitates in the fire,  melts before the blow-pipe
without addition, and fluxes dissolve it with effervescence.
—See the notes of die abbe Mongez.*
  Mr. Darcet succeeded in fusing it in  a porcelain fur-
nace.
* Manuel du Mineralogiste. 
240               PONDEROUS SPAR.
  It has been often  confounded with gypsum and fluor
spar;  but the  characters of these two substances are very
different.
  It almost  always accompanies metallic  ores, and it is
even considered as an  happy presage of finding them.  Be-
cher has affirmed that  it wras a certain indication vel pre-
sentis velfuturi metalli: and I think that there is reason
to consider it as the vitrifiable stone of this celebrated na-
turalist.  The proofs of my  assertion may be seen in the
preliminary ideas of my treatise on metallic substances (in
this work).  The analogy between this stone and metals
has been established by the experiments of Bergmann and
of Mr. Lavoisier.
  This stone, when  rather strongly  heated, exhibits a
blueish light in the dark.   To form these kinds of phos-
phori, the spar is  pulverized, the powder is kneaded up
with mucilage of gum tragacanth, and the paste is formed,
into pieces as  thin as  the blade of a knife.  These pieces
are afterwards dried, and strongly calcined by placing them
in the midst of the coals of a furnace;  they are afterwards
cleared by blowing on them with the bellows.   In this,
state, if they be exposed to  the light for a few minutes,
and afterwards carried into a dark place, they shine like
glowing coals.  These pieces shine even under water; but
they gradually become deprived of this property, which
however may be restored again by a second heating.—
See De Fourcroy.
   Ponderous  spar is easily divided  into  plates by the
slightest blow; and the most usual form which  it affects
is that of an hexahedral prism, very flat, and terminated
by a dihedral summit.
   Ponderous  spar has been found at the distance  of one
league from Clermont d'Auvergne, in the fonn  of hexa-
hedral prisms terminated by a tetrahedral or dihedral py-
ramid.   I have seen crystals of two inches in diameter.
   It frequently happens that the form of these Crystals is
not very determinate; but all the stones of the nature of
these exhibit a confused assemblage of several plates ap-
plied one upon another,  and capable  of being  separated
by a very slight blow.  Ponderous spar  is  insoluble in
water; and upon this property is founded the virtue pos-
sessed by the muriate of barytes, to manifest the slightest 
CARBONATE  OF  BARYTES.           241
portions of sulphuric acid in any combination which con-
tains it
  Barytes adheres more strongly to acids than the alkalis
themselves do; and when  the carbonates of alkalis pre-
cipitate it, the effect takes place in the way of  double af-
finity.*
                       SPECIES II.

                  Carbonate of Barytes.

   This combination has the specific gravity of 3.773.
   One hundred parts  contain  twenty-eight water, seven
acid, sixty-five pure earth.
   The sulphuric, nitric, and other  acids  attack  it with
effervescence.
   Although the carbonic acid possesses the strongest  af-
finity with this earth, it is  very  seldom found in combina-
tion with it: and I am acquainted with its existence only
on the  authority of Mr.  Kirwan, who affirms that  Dr.
Withering presented him with  a specimen from  Alston
Moor,  in Cumberland;  which  resembles alum, with the
difference that its texture is striated,  and its specific gra-
vity is 4.33l.f
   Mr. Sage analized this stone, which was presented to
him by Mr.  Greville.—See the  Journal de Physique for
April 1788.

  * Sulphate of barytes has been discovered of a white colour and
laminated texture,  in Sussex county,  New-Jersey.   It has also been
found in the sugar loaf mountain, not  far from the junction of the
Monocasy, with the Potowmac, in  Maryland, and  in  Bottertot
county, Virginia.   Lapis Hepaticus, the liver stone of the Germans
and Swedes, or bituminous sulphate  of barytes, is likewise found
in the county of Albemarle, Virginia.—Am. Ed.
  t It is plentifully found in England, in the lead  mine of Angle-
zark, near Chorley  in Lancashire.  See the Manchester Memoirs,
vol. iii. p. 598.  T.
Hh 
MURIATE OT BARYTES.
                     SPECIES III.

                 Nitrate of Barytes.

  The nitric acid dissolves pure barytes, and forms a salt
which crystallizes sometimes in large hexagonal crystals,
and frequently in small irregular crystals.
  This nitrate is decomposed  by fire, and  affords oxi-
gene gas*
  The pure alkalis do not disengage the barytes,  but the
alkaline carbonates precipitate it by double affinity.
  The sulphuric and fluoric  acids seize this earth from
the nitric acid.
  It has not yet been found native.


                     SPECIES IV.

                 Muriate of Barytes.

  This salt is capable of assuming  a form  considerably
resembling that  of spar in tables  or plates.   It exhibits,
with the earths, acids, and alkalis, phenomena nearly simi-
lar to those of the nitrate of  barytes.
  It forms one of the most interesting re-agents to ascer-
tain  the existence of the smallest  particle  of sulphuric
salt in any water;  because,  by the  sudden exchange of
principles, the result is ponderous spar,  which immedi-
ately falls down.
   It has not yet been found  in a native state.
                     GENUS III.

        Earthy Salts with Basis of Magnesia.

  These salts were not well known before  the  time in
which the celebrated Black proved that they ought not to
be  confounded widi  calcareous  salts.   They may  be 
EPSOM SALT.
243
distinguished from these by the bitter taste which  almost
all of them possess.
  They are in general very soluble in water.   Lime-wa-
ter precipitates them, as does likewise ammoniac,  or  the
volatile alkali.


                      SPECIES I.

          Sulphate of Magnesia., Epsom Salt.

   This salt is frequently met with;  it exists  in  several
mineral waters,  such as those of Epsom,  of Sedlitz,  &c.
 It was at first distinguished by the name  of the  springs
which produced it;  and it is still known by the name of
 the bitter  cathartic salt, on account of its  taste and  vir-
 tues.
   The sulphate of magnesia, in commerce, comes either
 from  the salt springs of Lorraine,  from which this salt is
 extracted with  a mixture of sulphur; or otherwise from
 the salt works in the environs of Narbonne, where  it is
 extracted from  the mother waters which contain it abun-
 dantly.
   The sulphate of magnesia,  in commerce, has the form
 of small silky needles, very white.  It does not effloresce
 in the air, which distinguishes it from the sulphate of soda.
   The crystals of the pure sulphate  of magnesia are qua-
 drangular prisms, terminated by pyramids of an equal
 number of sides.
    The sulphate of magnesia prepared in  our  salt works
 is sold at from thirty to forty  livres  the  quintal; it  con-
 tains in the pound three  sixteenths  of sulphate  of soda,
 two sixteenths muriate of magnesia, one sixteendi muri-
 ate of soda, six sixteenths true  sulphate of magnesia:
 the rest consists of salts with basis of lime.
    The sulphate of magnesia, when exposed  to  the fire,
 liquefies, and  loses half its weight.  The remainder is
 dry,  and requires a strong fire to fuse it.
    Water dissolves its own weight of this salt, at the tem-
  perature of  60 degrees of Fahrenheit's thermometer.
    One hundred parts of this salt contain twenty-four parts
  acid, nineteen earth, and fifty-seven wrater. 
244
MURIATE OF MAGNESIA.
   It exists in all the waters in the environs of Montpel-
lier.
   Sometimes it is found efflorescent upon schisti, from
which it may be collected.  I have found it upon a moun-
tain in Rouergue,  in a quantity  sufficiently great  to be
collected to  advantage : birds of passage devour it gree-
dily.   This salt is used in preference to others as a pur-
gative.*


                     [SPECIES II.

                Nitrate of Magnesia.

   The celebrated Bergmann,  who has combined magne-
sia with the various  acids, observes that the nitric acid
forms with it a salt capable of affording, by proper eva-
poration, prismatic, quadrangular, truncated crystals. The
same chemist adds,  that this  salt is deliquescent.  Mr.
Dijonval affirms,  that he  obtained crystals that were not
deliquescent; and accident has afforded me a salt of this
kind in mother water of nitre concentrated to the 45th de-
gree of the aerometer.   Its form was that of prisms with
four sides,   very  much flattened, very thick, and  very
short.
   This salt decomposes the muriates;  alkalis precipitate
its magnesia, as does likewise lime.


                     SPECIES III.

                Muriate  of Magnesia.

   The muriate of magnesia exists in the mother water of
our salt works; its taste is very bitter.
   According to Bergmann, it forms a salt in small nee-
dles,  so deliquescent that it cannot  be  obtained  but  by
strongly concentrating the  solution, and afterwards expos-
ing it to intense cold.

  * Immense quantities of this salt are found under the surface of
the earth in Monroe county, Virginia.—Am. Ed. 
CARBONATE OF  MAGNESIA.
245
   Lime-water, barytes, and the  alkalis  precipitate the
 magnesia;  it may likewise be separated by means of fire.

                     SPECIES  IV.

                Carbonate of Magnesia.

   Though magnesia has the greatest affinity with the car-
 bonic acid,  I do not think that nature has ever exhibited
 this combination. It is obtamed by precipitating the mag-
 nesia from Epsom salt, by  means of the  carbonates of
 alkali;  and in this state it  is  called effervescent magnesia,
 or magnesia not calcined.
   The carbonate of magnesia contains in the quintal thir-
 ty parts acid, forty-eight earth,  and twenty-two water.—
 See Kirwan and  Bergmann.
   Magnesia sticks to the tongue;  and assumes, in  drying,
 a certain transparency,  which it preserves until it has lost
 all its water, which is not easily driven off.
   Fire carries off the  water and the acid; and  in this
 state the residue  is  called calcined magnesia.
   The carbonate of magnesia is soluble in water in the
 proportion of several grains  in an ounce of the fluid.
  But we are indebted  to Mr. Butini for a  very singular
 observation—that cold dissolves more than hot water, and
 that the magnesia may be precipitated by heating the wra-
 ter which holds it in solution.  Hence it arises that wa-
 ters loaded with magnesia  become white and  turbid by
 ebullition.
  The celebrated Bergmann had advanced  that the car-
 bonate of magnesia is crystallizable.   Mr. Butini, by con-
 centrating a saturated solution of this salt  with a gentle
 heat,  obtained groups of crystals, which, when examined
 by  the microscope, appeared to  be hexagonal truncated
 prisms.  I have obtained similar snow-like flocks by pre-
 cipitating magnesia by the addition of an alkali, drop by
 drop.
  The carbonate of magnesia is used in medicine as a
 purgative.   The  calcined magnesia ought to be preferred
as an absorbent. 
246
ALUMINOUS  SALTS.  *
                     GENUS IV.

         Earthy Salts with Base of Alumine.

  The substance which in the arts is known by the name
of Clay, is a natural mixture of several earths.
  Alumine, or pure  clay, is capable of combining with
the greatest part of the known acids; but the most com-
mon of these salts is alum.


                     SPECIES I.

              Sulphate of Alumine, Alum.

  Though alum be very commonly met with, yet the
combination of principles which constitute it is not effect-
ed without considerable difficulty.
  Pure clay upon which  the sulphuric acid is digested, is
dissolved with difficulty;  and  it is by no means easy to
bring this  combination to regular crystals.   The usual
product is a salt, which appears to be formed by scales
applied one upon the other.
  The  most  ordinary' process to  dissolve  alumine by
means of an acid,  consists in calcining the clay,  impreg-
nating it with the acid,  and facilitating its action by an
heat of 50 or  60 degrees of Reaumur.  But a  simpler
method, which I have used in my manufactory  of alum,
consists in presenting the  acid in vapours, and under the
dry form to the clay properly prepared.   For this purpose
I calcine my clays, and reduce them into small pieces,
which I spread over  the  floor  of my  leaden chambers.
The sulphuric acid, which is formed by the combustion
of a mixture of sulphur  and saltpetre,  expands  itself in
the cavity of these chambers and exists for a certain time
in the vaporous form.  In this form it has a  stronger ac-
tion than w hen it has been weakened by the  mixture of
a quantity  of  water more or less considerable : so that  it
seizes the earths, combines with them, causes  them to
increase in bulk by the efflorescence which  takes place,
and at the end of  several days the whole surface exposed 
MANUFACTURE OF ALUM.
247
to the vapour is converted into alum.   Care is taken to
stir these earths from time to time, that they may suc-
cessively present all  their surfaces to the action of the
acid.                              .          ♦
   But whatever process may be used to combine the acid
with clay,  it is necessary to expose the aluminized earths
to the air during a greater or less space of time, in order
that the combination may be more accurate, and the  sa-
turation more complete.
   Most of the alum in commerce  is  afforded by ores
which are  dug out of the earth for this purpose.*  We
may reduce all the operations of this manufacture to three
or four; the decomposition of the ore,  the lixiviation of
the ore, the evaporation of these lixiviums, and the cry-
stallization of  the alum.
   1. The decomposition of the mineral is effected either
 in the open air without assistance, or else by means of fire.
   When the mineral is left to decompose spontaneously,
 nothing more  is done than to dispose the stone which con-
 tains the principles of alum in strata or layers.   The py-
 rites becomes heated;  acid is formed, which dissolves the
 clay ; and the salt arising from this combination exhibits
 itself by the efflorescence of the ore.  The decomposition
 may be accelerated by watering the  heap  of pyrites;' but
 the operation may be still more abridged by the assistance
 of fire.—The method of applying the  heat varies prodi-
 giously.    On this head Bergmann may be consulted; but
 in general it may be  observed that it ought not to be
 either too strong or too weak.   In  the first case it vo-
 latilizes the sulphur,  and in the second it  retards the
 operation.
    The ore of  alum is sometimes  impregnated with a suf-
 ficient quantity of bitumen to maintain the combustion.
  __See my Memoir on the Alum Ore of  Vabrais, 1785.
    2.  When the ore has effloresced into alum, the salt is
 extracted by lixiviation.  For this purpose the same wra-

    * Alum  is said to be found in great quantities, near Fort Pitt, in
  Pennsylvania ; in the townships of Barrington, Orford and Jaffrey,
  New-Hampshire ;* on the Shawangunk mountain, in New-York.t
  and in the  upper parts of South-Carolina.t—Am. Ed.
   * Belknap, vol. iii. p. 194.
   t Med. Repository, Hexade ii. p. 194.
    % Drayton. 
248
MANUFACTURE OF  ALUM.
 ter is passed over several heaps of aluminous earth, in or
 der to saturate it.  The water which is first passed  over
 the earth dissolves  in  preference  the vitriol, which is
 more or less abundant;  and this salt may  be separated
 from the alum by a previous cold-washing.
   3. This lixivium, or saline  solution,  is carried  into
 leaden caldrons,  where the fluid is properly concentrated.
 In this part of the process it is that an accurate satura-
 tion of  the alum is effected when the  acid is  in excess;
 and for this purpose alkalis are added, which  serve like-
 wise singularly to facilitate the crystallization.   The cele-
 brated Bergmann has proposed to boil clay with the solu-
 tion, to  saturate  die excess of  acid.   This process seems
 in every point of view  to be  advantageous;  but it ap-
 pears to me to be impracticable, because the superabun-
 dant acid cannot be made to combine with  the clay but
 by a very  long ebullition ; and I have  observed that, by
 afterwards evaporating the fluid to cause it  to  crystallize,
 this clay falls down,  and opposes the crystallization.  I
 have varied the process in a variety of ways, without ob-
 taining the success which its celebrated author predicted.
   There are methods of greater  or less accuracy to judge
 of the degree of concentration to which it  is  proper to
 carry the lixivium ;  in order to obtain a good crystalliza-
 tion : such are, the immersion of an  egg in  the liquid,
 the effusion of some  drops of the  lixivium on a plate,
 &c.  Mr.  De Morveau has proposed a metallic hygrome-
 ter ; but this instrument cannot be considered as very ac-
 curate, because its immersion in the liquid is proportional
 to the heat of the fluid in which it is plunged.
   4.  The  lixivium is then conveyed into coolers, where
 it crystallizes by  mere  refrigeration.  The  pyramids of
 alum are constantly turned towards the bottom of the ves-
 sel,  more especially  thpse which fix  themselves to the
 sticks which are  put  into the liquor  to  multiply  the  sur-
 faces.
   Alum affects the form of two tetrahedral pyramids, ap-
 plied to each other, base to base.  Sometimes  the angles
 are truncated, and these truncatures take place  most fre-
 quently when the lixivium is slightly too acid.
   This salt requires fifteen times its weight of water to
dissolve it, at the temperature of 60 degrees of Fahren-
heit,  according to Kirwan. 
CARBONATE OF  ALUMINE.
249
   Its taste is stypic;  it loses  its water of crystallization
by heat;  at the same time that it swells up, and  is con-
verted into a light and white substance, called  burned or
calcined alum.
   If it be urged by a violent degree of heat, it loses part
of its acid,  and becomes  tasteless.   The residue is  no
longer  susceptible of crystallization, and precipitates in
the form of a very fine adhesive powder,  in proportion as
the water is dispersed by evaporation.
   Alumine is precipitated  from this solution by magnesia,
barytes, and the alkalis: these last dissolve the precipitate
in proportion as it is formed, if they be added in excess.
   Alum is a very valuable material in the arts.  It is the
soul of the art of dying, and  serves as  the  mordant to
all colours.   It is used to prepare leather,  to impregnate
paper and cloths intended  to be printed.  It is added to
tallow, to render it harder; it enters into  the preparation
of a glue  for the destruction of vermin ; it is employed in
England, and elsewhere, to give whiteness and additional
weight, to bread.   When  fused with saltpetre  of the first
boiling, it forms a very white crystal mineral.
   The printers rub their balls with calcined alum, to cause
them to take the ink.  Surgeons employ it to corrode fun-
gous or proud flesh.


                      SPECIES II.

                 Carbonate of Alumine.

   The argillaceous earth precipitated from the solution of
alum by die carbonates of alkalis,  combines with their
acid;  but this salt is very  rarely found  in nature  I know
only of the observation of Schreber which ascertains its
existence.  This  naturalist asserted that the earth known
by the name of Lac Lunae is a true carbonate of alumine.
   Although alumine be soluble in the other acids, we are
very little acquainted with its combinations.   It  is only
known that the nitric acid  dissolves  it, that the solution is
astringent, and that it may be obtained ia small styptic
and deliquescent crystals. 
250
EARTHY MIXTURES.
    The muriatic acid has a more evident action upon alu-
 mine.   This muriate is gelatinous and deliquescent.
    These salts have not been applied to any use, and they
 are no where found in nature.


                       GENUS V.

            Earthy Salts with Base of Silex.

    Silex is of all the known earths that which combines
 the most difficultly with acids.
    We are even acquainted with no other acid than the flu-
 oric which exerts an  evident action upon it.  It rises with
 it, and holds it in solution until it abandons it to unite with
 water.
    Some experiments of Mr. Achard gave  reason to think
 that the  carbonic acid dissolved silex;  but  the  Parisian
 chemist did not obtain the results announced by  the che-
 mist of Berlin.  M. De Morveau seems to have proved that
 iron and the carbonic acid were necessary  to form rock
 crystals:  but this acid does not remain united and com-
 bined  with the earth; so that we have not hitherto arrived
 at any proof of its dissolving virtue,


                       CLASS II.

 Concerning the Combination  and Mixture of Primitive
              Earths, or Earthy Mixtures.

   The pure and simple earths, such as we have describ-
 ed them,  are rarely found on the surface of the globe.
 They are constantly mixed with each other,  and form mas-
 ses of greater or less magnitude, and various hardness, ac-
 cording to the nature  of the earths, their state of division,
 and the character of the foreign substances which are com-
 bined with them, such as iron,  bitumens, he.
   It may be easily understood that the number of compo-
 sitions vvhich can result from the mixture of five primitive
earths, would  be infinite,  if we were to pay attention to
such slight varieties as depend on die* proportions of the
mixture: but  I shall not consider any mixtures as consti- 
               CALCAREOUS MIXTURES.           251

tuting species truly distinct, except such  as  differ in the
identity of their constituent principles.  The  slight  diffe-
rences in the proportions of these  principles  may indeed
occasion modifications in the form, the hardness, the co-
lour,  he.   But these can never constitute more than va-
rieties.
   We shall naturally deduce the genus from the stone or
eardi which predominates in any mixture, and appears to
communicate its own character to the total mass.  In this
manner we shall class among the calcareous mixtures such
stones as  exhibit to our observation the properties of lime-
stone to  such a degree, that they would be taken to be
purely calcareous if the chemical analysis did not prove the
existence  of other principles.
   The  genus ought not in strictness to be taken and de-
duced from the earthy principle which predominates; for
the character of the whole mass or of the mixture, is very
frequently given by an earth which does not form the most
abundant principle;  as we observe more especially in mag-
 nesian earths, where the  silex   predominates over the
 magnesia.


                       GENUS I.

                 Calcareous Mixtures.

   According to the principles we have laid down, we must
 refer to this place those stony mixtures in which the pro-
 perties of lime-stone predominate.


                      SPECIES I.

               Lime-stone and Magnesia.

   This mixture is very common; almost all the calcare-
 ous  stones  contain magnesia.  Mr. Bayen has described a
 variety in the  Journal de Physique, t. xiii.  which contain
 in the  hundred parts  seventy-five   carbonate of lime,
 twelve magnesia,  and  thirteen iron:  it is the earth  of
 Crentzwald.  Mr. Woulfe has described  another  variety
 in the Philosophical Transactions for 1779.  It afforded 
252
EARTHY MIXTURES.
sixty parts carbonate of lime, thirty-five carbonate of mag-
nesia, and three of iron.
  The analyses which I have made of several lime-stones
in our province, constantly afforded magnesia.

                     SPECIES II.
               Limestone and Barytes.
  Mr. Kirwan has  informed us that this species is found
in Derbyshire, in the form of a stone, and likewise in the
earthy state.   It is  of a grey colour, and harder than or-
dinary lime-stones.

                     SPECIES III.

           Carbonate of Lime and Alumine.

  This mixture is frequently met with.  It is commonly
known by the name of Marl.    The proportions of the
two constituent principles  are infinitely various.    It is
upon this proportion that the distinction of fat marls and
lean marls depends, and disposes them to serve as manure
for earths of different kinds.  The marls are almost al-
ways coloured by iron.
  They appear to arise from the decomposition of the na-
tural mixtures of chalk and clay, and contain more or less
of silex ; but the analysis which I made six years ago of
all  the  marls I could procure, convinced  me  that they
were often nothing more than a mixture of clay and chalk.
I have likewise found magnesia in marls,  sometimes  in
the quantity of seventeen parts m the hundred; but, in ge-
neral, they may be  considered  as formed essentially by the
two earths here mentioned.
   Alumine is found likewise mixed with carbonate of lime
in marbles.  Mr. Bayen has proved this in the second vo-
lume of the Journal de Physique:  and I have confirmed
the truth of his results by the  analysis of several marbles
of our province.  It is eyen upon this principle that we may
account for the greasy polish which some of them take.
   The very evident difference which may be established
between the mixtures  which  form marl and marble,  is,
that the first is the  immediate product of a decomposition
principally effected  by the alterations of the iron which it 
EARTHY MIXTURES.
253
contains;  whereas, the second is produced by a purely
mechanical mixture of two principles  already  formed,
which being pounded,  and ground as it were together,
form a compact, hard, close assemblage, susceptible of the
most beautiful polish.


                     SPECIES IV.

                Lime-stone and  Silex.

   This species is not  common.  It is known under the
name of Stellated Spar, Stern Schoerl of the Germans. It.
is opake, of a  radiated  texture or form.  Mr. Fitchel
found it in lime-stone on  the Carpathian mountains.  It
effervesces with acids; and, according  to Mr. Bindheim,
one hundred parts of this stone contain sixty-six carbonate
of lime, thirty silex, and three iron.—See Kirwan.
   The  mixture of the pulverulent remains of the primi-
tive rocks transported into our country by the rivers which
rise in the  Alps and the Cevennes, together with our own
calcareous  fragments,  frequentiy  foim beds of a stone of
this nature.  The only difference between them  is, that
our mixtures exhibit a confused assemblage "of all the prin-
ciples which belong to the primitive rocks, such as clay,
silex, and others.
                     SPECIES V.

               Limestone and Bitumen.

  This mixture is known by the name of Swine-stone.  It
abounds in the diocesses of Alais and Uzes:  I have seen
the calcareous rock impregnated with bitumen in an ex-
tent of more than  three leagues diameter.   It is even so
abundant in some parts, that it distils through the clefts of
the rocks, and forms stalactitous bitumen, which the pea-
sants collect to  mark their  sheep, or to grease their cart-
wheels.  The heat of our summer sometimes softens it to
such a degree, that it flows into the roads, wiiere it ad-
heres to and impedes the motion of the sledges and other
carriages. 
254              EARTHY MIXTURES.
   In some places the stone is so well impregnated with
bitumen, that it may be wrought;  but the blow of a ham-
mer causes it to emit an abominable smell.  Mr. D'Ave-
jan, bishop of Alais,  having used  this stone  to pave the
apartments of his palace, the friction and heat disengaged
so unpleasant a smell, that his successors were obliged to
substitute a stone of another kind in its stead.
   Mr.  De la Peyrouse found this  stone in large masses
near Saint Beal in  Comminge, at  L'Estagneau, and the
mill of Langlade.
                     SPECIES VI.

                 Lime-stone and Iron.

   Iron is almost always a constituent part of lime-stone;
but it sometimes exists in such a proportion, that these
mixtures constitute iron ores. Mr. Kirwan describes two
of this nature; one of which  contains twenty-five pounds
of iron in the quintal,  and the other  ten.  Mr. Rinmann
has described stalactites  which afford  iron, in  the pro-
portion  of  from twenty-seven to twenty pounds in  the
quintal.
  Calcareous iron ores are wrought  in many parts of  our
province.   I have myself obtained  forty-four pounds of
iron in the quintal, from a calcareous stone which abounds
on the mountain of Frontignan.
  It is common to find, in our calcareous mountains,  he-
matites rich in iron, whose base is calcareous; we find like-
wise species of ludus of the same genus, and sometimes
even tufa, whose formation arises from waters loaded with
iron and lime.
  The spathose iron ores are of the same class as those we
have just treated of.

                     GENUS II.

                  Barytic Mixtures.

  These mixtures are very rare, because the stone itself
is scarce.   We shall mention only two species. 
EARTHY MIXTURES.             255
                     SPECIES I.

Sulphate of Barytes, Petroleum, Gypsum, Alum, and Si-
  lex.—Bergmanni Sciagr. s. 90; Kirwan Min. p. 60.

  The name of Hepatic Stone (Lapis Hepaticus) has been
given to this mixture.
  The colour varies much:  its texture is uniform, lamel-
lated, scaly, or sparry.   It takes the polish of alabaster.
  It forms a kind of plaster by calcination,  and emits a
strong and fetid smell by friction.
  One hundred parts of this stone contain thirty-three ba-
rytes, thirty-eight silex, seventeen  alum, seven gypsum,
and five petroleum.


                      SPECIES II.

         Carbonate of Barytes, Iron, and Silex.

  Mr.  Kirwan has mentioned this stone on the authority
of Mr. Bindheim.  It is insoluble in acids, and  of a sparry
texture; but he is tempted  to consider it as a  sulphate of
barytes, in consequence of the property observed by Mr.
Bindheim, that it becomes soluble in  acids,  after having
been calcined with oil.
                     GENUS III.

                Magnesian Mixtures.

  All the species comprised in this genus possess charac-
ters sufficiently striking, and easily known.   They are in
general greasy and soft to the touch; they may be cut with
a knife, turned in a lathe, and converted into any form at
pleasure.  They take a tolerably good polish.  Some of
them are disposed into fibres;  and these fibres possess for
the most part, a remarkable degree  of flexibility.   They 
256
                 5ARTHY MIXTURES.

stick to the
  ten,t„¥el^ ** ^ but d° "ot> ^ *™' «*


                        SPECIES I.

            Pure Magnesia, Silex, and Alumine.


                       SPECIES II.

       Carbonate of Magnesia, Silex, and Alumine.

    The mixture of these three earthy principles forms
  talfe St5a£teS' ******** or lapides oLres.   ?
    I he  difference which analysis shews between these two
  species,  is almost entirely confined to the proportions of
  their constituent principles.   This circumstance might ap-
  pear sufficient to authorize us in considering them only as
  varieties of each other.  But as the magnesia is pure i/the
  talk, and in the state of carbonate in the steatites, we shall
  consider them as different species.
    1.  Pure magnesia, mixed with near twice its weight of
 silex, and less than its weight of alumine,  forms talk   It
 is of a white, grey, yellow, or greenish colour :  soft and
 soapy to the touch, composed of transparent lamina placed
 upon each other.  These lamina  are  more  tender  than
 those of mica; they lock together, and are usually divided
 into rhombi, and may be crushed or scratched with the
 nan.
   Its specific gravity is 2.729.
   Fire renders it more  brittle and white; but it is infusi-
 ble by the blow-pipe,  and can scarcely be fused by the
 addition  of alkali.  The borate of soda, and the phosphate
 of urine, fuse it with a slight effervescence!
   Muscovy talk is composed of large elastic, flexible, and
 transparent leaves.   Plates  of  talk have been raised in
 the quarries of Vitim  in Siberia which were eteht  feet
 square.*                                      &

^iL™1 is/ound1in New-Hampshire, adhering to  rocks of white or
yellow quartz, and lying ,n lamina like sheets of paper.  The most
ot it is white, some is yellow, and some has a purple hue. The larg- 
EARTHY MIXTURES.              257
   2.  Steatites is usually of a  greenish white:  it may be
easily cut with a knife;  and the dust which is produced
by scraping it does not readily mix with water.
   Its specific gravity is about 2.433.
   It is  infusible alone, hardens in the  fire, and becomes
white.   The  borate of soda facilitates  its fusion;  but
soda, and the phosphates of urine, do not perfectly dis
solve it.
   According to the analysis of  Bergmann, one hundred
parts of steatites contain eighty silex, seventeen magnesia,
in the state of carbonate, two alumine, and one iron.
   Steatites is sometimes found in masses of indeterminate
figure,  and  sometimes crystallized, such as  that  which
Mr. Gerhard found at Raichewtein in Silesia. Chem. Ann.
1785.—And Mr. Rome de Lisle possesses crystals in hex-
agonal  lamina resembling the leaves of mica.
   The white steatites of Briancon is composed of irregu-
lar, friable, and~semi-transparent leaves.   It often incloses
crystals of steatites, of a white or greenish colour,  which
have the form of tetrahedral prisms.
   The steatites of Corsica appears to be formed by fibres
placed  beside  each other.   It  has a  greenish  colour, and
no perceptible degree of flexibility.
   The steatites of Bareith is grey, compact and solid.

est leaves of this curious substance are found in a mountain, in the town-
ship of Grafton, about twenty miles eastward of Dartmouth college.  It
was first discovered in the following manner: A huntsman took shel-
ter for the night, in a cavern of the mountain,  and in the morning
found himself surrounded with this transparent substance,  a large
leaf of which he fastened to the branch of a tree,  near the cave, as a
mark by which he might again find the place. This happened during
the revolutionary war, when window-glass could not be imported.
The scarcity of that article, brought the talk into repute.  Many per-
sons employed their time in blowing the rocks, separating the lami-
nae, cutting them into squares, and vending them about the country.
This substance is particularly valuable lor the windows of ships, as it
is not brittle, but elastic, and will stand the explosion of cannon.  It
is also used to cover miniature paintings, and to preserve minute ob-
jects for the microscope.  The disadvantage of it for windows is, that
it contracts dust, and is not easily cleaned, but for lanterns it is prefe-
rable to  glass. (Belknap's History of New-Hampshire, vol. 3, p. 193.)
   The rocks of granite near Philadelphia are interspersed with talk,
often of a black colour.-i-vfm. Ed.
                          Kk 
258
Earthy mixtures.
   That of Queen Charlotte's Bay in New Zealand is stri-
ated, green, semi-transparent, and sufticientlv hard to give
fire with the steel.
   3. The soap-stone of China is a steatite, often striated;
but it is not more unctuous than those we have already
mentioned.
   The steatites of Briancon forms the basis of the vegeta-
ble red.*
   4. The lapis ollaris, or pot stone,  is only a variety of
the steatites.   It  does not appear to  me to differ from it,
excepting in being harder.
   Its colour is usually greyish ;  but it is sometimes black-
ened by bitumen.
   Mr. Gerhard has observed that the lapis ollaris of Swe-
den effervesces with acids, and contains calcareous earth;
but this mixture  is peculiar to it.  Those of Saxony, Si-
lesia and Corsica, do not contain it.  The kipis ollaris
may be wrought  with the greatest facility.   In the coun-
try of the Grisons,  in Corsica,  and elsewhere, it is turn-
ed, and  formed  into vessels  which  resist the  fire, and
have not  the  inconvenience of our glazed pottery;  it is
from these uses that it has  obtained  the name  of Lapis
Ollaris, Pot Stone, he.
                      SPECIES III.

 Pure Magnesia combined with somewhat more than its
   weight of Silex, one-third of Alumine, near one-third
   of Water, and more or less of Iron.

   This mixture forms the serpentine.  It has a great ana-
logy with the preceding substances,  but is  distinguished
from them  by  a more  evident  degree of hardness;  by
the property of acquiring a more  beautiful polish;  and by
a quantity of iron sufficiently considerable to  afford  it a
peculiar character.

  * Steatites is found fifteen miles from Philadelphia, on the banks of
the Schuylkill; in South-Carolina, in the neighbourhood of Hill and
Haynes' iron works; and at Orford on Connecticut river, New-Hamp-
shire-  Belknap says, it has the property of fullers.' earth in cleaning
cloths.—Am. Ed. 
earthy mixtures.              25£
   The serpentine is whitish, greenish, blueish, or black-
ish ; frequentiy marked with black spots ; and sometimes
intersected with bands of various colours.  Some serpen-
tines are even transparent.   The Royal Cabinet of Mines
possess a specimen whose ground is grey, and interspers-
ed with reddish semi-transparent and chatoyant spots.
   Serpentine varies likewise in its texture.
   It is compact, granulated, scaly, lamellated, or fibrous.
   It takes the most beautiful polish.
   The iron it contains is sometimes  obedient to the mag-
net.
   Its specific gravity is from 2.4 to 2.65.
   It melts in a violent heat; but a less degree of fire har-  '
dens it.
   Mr.  Bayen, who has analized  the serpentine, found it
to contain, in the hundred parts,  forty-one  silex,  thirty-
three magnesia,  twenty alumine, three  iron, and also
water.
   Mr. Kirwan has observed, that the serpentine of Cor-
sica, contained more alumine,  and less silex.
   Mr. De Joubert possesses a species of serpentine which
exhibits square plates on its surface.   ,
   Mr. Dorthes has observed several  varieties of the ser-
pentines on  our  Mediterranean  coasts,  and in the river of
Herault, which receives them from the mountains  of  the
Cevennes.


                     SPECIES IV.

 Carbonate of Magnesia ;  Silex, Lime, Alumine, and
                         Iron.

  This combination exhibits several  varieties,  which  are
known  under the name of Asbestos, Mountain  Cork.
Their texture serves to distinguish them;  but the che-
mical analysis confounds them together, and  does not per-
mit us to allow any other distinction than that of varieties. 
260
EARTHY  MIXTURES,
VARIETY I.

  Asbestos.
 •Jrh^,Stone " USually  &***&; Jts texture  is some.
 times fibrous  and compact,  and sometimes membrana-
 ceous.
   Near Bagneres de Bigorre, in the mountains of the en-
 virons of Bassere, Messrs.  Dolomieu and La Perouse
 found crystals of asbestos in rhomboidal parallelopipeds
   Asbestos is rough to the touch, brittie and ruffled  Its
 specific gravity is from 2.5 to 2,8.
   Fire renders it whiter and more brittie.  It is infusible
 by the blow-pipe,  according to Kirwan;  but the  abbe
 Mongez affirms that asbestos and amianthus are fusible,
 and form an opaque globule, which becomes blueish.   It
 is difficultly soluble with soda;  but more easily  with  bo-
 rate of soda and the phosphates of urine.
   According to Bergmann,  the  asbestos contains in  the
 quintal from fifty-three to seventy-four parts silex, about
 sixteen magnesia, from twelve to twenty-eight carbonate
of lime,  from two to six alumine,  and from one to two
iron.*
                     VARIETY II.

                   Mountain  Cork.

   This name has been given on account of a slight re-
semblance of this substance to cork.   This stone is very
light, membranaceous,  flexible, and usually of a yellow
colour.   It may be more easily torn  than broken.  The
diocese of Alais affords very fine specimens.
   Among a very great number of  stones of this  nature,
subjected to analysis by the celebrated Bergmann, the si-
liceous earth was always found predominant; and  after

  * Asbestos is found in Chester county,  Pennsylvania; in the state
of New-York, and at  the head waters of Lynch's creek, South-Ca^
rofina.—Am, Ed. 
                 EARTHY  MIXTURES.             261

that  the  magnesian,  which was never less  than  twelve
parts in the hundred, nor more than twenty-eight.


                     SPECIES V.

Carbonate of Magnesia and Lime, Sulphate of Barytes,
                 Alumine, and Iron.

  This combination forms amianthus.  It is composed of
long flexible fibres, parallel to each other, and very soft
to the touch.
  They are sometimes very white,  but often  yellowish.
The filaments may be separated and detached from  each
other; and may be even twisted in any direction without
danger of breaking them.   Their flexibility is so wonder-
ful,  that they may be formed  into cloth.   The ancients
constructed  cloths of this kind, in which they burned the
bodies of the dead;  and by this means  the ashes were
collected without mixture of those of the fuel.
  Mr. Dorthes found amianthus in tufts upon calcareous
stones thrown up by the sea, on which it was fixed with
plants, corallines,  gorgonia, he.  He believes, with rea-
son, that this amianthus did not originate upon the stones,
but that  it was deposited by the water.   He found,  like-
wise, on the coast, balls of the amianthus of two or three
inches diameter imitating aegagropiles, and formed by the
intertwining  of the threads of amianthus;  and covered
\vith a white tophose substance, of the  nature  of that
which covers the gorgonia, and is the work  of a  species
Of sea animalcule.
  The fibres of  amianthus are of various lengths.   I
have received specimens from  Corsica, whose filaments
were very flexible, and eight inches long.  That from the
Pyrenean mountains  has shorter fibres.
  Bergmann  analized an amianthus from the vicinity of
Tarento, of  which 100 parts afforded 64 silex, 18.6 mag-
nesia,  6.9 lime,  6 sulphate of barytes, 3.3  alumine, 1.2
iron. 
EARTHY MIXTURES.
                     GENUS IV.

                Aluminous Mixtures.

   Argillaceous or aluminous stones are common enough.
They are seldom possessed of more than a moderate de-
gree of hardness, and  are  divisible in water.   But the
mixture of their principles is in  some  instances so inti-
mate, that  they possess a veiy strong  degree of consist-
ence.
                      SPECIES I.

Alumine, Silex, Carbonate of Lime, and more or less
                       of Iron.

   We may here place all the varieties of clay.   Chemi-
cal  analysis exhibits  constantly enough the  principles
whose mixture  forms this species; but the proportions
among these constituent principles vary so much, that the
varieties of  clay are almost infinite.   Independent of the
principles above enumerated,  we  sometimes  find lime
combined with clay, and  sometimes even magnesia; and
it will be easy to form various  species, in proportion  as
the analysis of these earths shall become more perfect.
   The argillaceous mixtures of which we propose at pre-
sent to speak,  are characterized by the following proper-
ties :—They adhere strongly to the tongue,  become  dry,
hard, and  shrink  in  the  fire;  are  divided, and form a
paste, with  water,  in  which state  they  may  be easily
moulded and turned,  &c.  The clays  in which the sili-
ceous principle is most abundant are, the driest, adhere
less to the tongue,  are less completely  diffused  in water,
and  crack less  when  dried by the  heat of the fire or the
sun.
   Most  clays contain iron;  and this metal is usually the
principle of their colour.  From the  brownish  clay,  in
which iron is almost in the native  state,  to the deepest
red,  all the various shades are owing to  the several de-
grees of alteration in this  metal.  These various changes 
EARTHY MIXTURES.  POTTERY.       26S
  are effected either at the surface of the globe by the im-
  mediate action of the air, which calcines the iron, or else
  in the bowels of  the earth;  in which last case, the effects
  arise from the decomposition of water and of the pyrites.
  We may  trace this beautiful  work  of nature  in several
  pyritaceous strata in our province;  and on this subject re-
  ference may be had to my Memoir upon the Brown Red
  (Brun Rouge), printed by Didot by order of the province.
     We shall direct our attention  less to the several varie-
  ties of clay than to the uses to  which they  are applied.
  The first  of these uses is to form the basis of pottery.
     Several species of pottery may be observed, which ne-
  vertheless differ from each other only in  the  degree of
  fineness of the earths made use of, and the care that has
  been taken in performing the various manipulations which
  they undergo.
     1. The most common pottery is made with any kind of
  clay indiscriminately, which is mixed with sand, to render
  it more porous, and by this means more adapted to  sup-
  port the heat.
     These  vessels  would be penetrable by  water, if tiiey
  were not  covered with a glaze.
     The glazes of pottery are usually made  either with the
  sulphureous lead ore,  called Alquinfoux,  and in En-
  gland, Potter's Lead Ore, or with the yellow copper ore.
  For this purpose, these substances are reduced to powder,
  mixed with water, and the  vessel,  previously dried by a
  slight baking, is dipped in the mixture.  The porous ves-
  sel absorbs the water, while its surface becomes covered
  with the pounded ore.   The vessel is then carried to the
  furnace, and baked by a heat which vitrifies the ore  upon
  its surface : and it is this metallic glass which  forms the
  glaze of the potters, and is yellow or green, according to
  die metal made use of.
     These  glazes are all dangerous;  because they are so-
  luble  in fats,  oils, acids, &c.
     The  attention  of intelligent  manufacturers  has  been
-  long directed to the methods of  substituting in  the  place
  of these glazes, others which are  not attended with the
  same  danger.
     We might, after the  manner of the English, vitrify
  the surface of our pottery by means  of sea  salt thrown 
264
EARTHY MIXTURES.   POTTERY.
 into the fire-place when the furnace is at a white heat;
 but this method is impracticable in most of our manufac-
 tories,  because our fires are not sufficiently strong.
   I have tried various methods to glaze pottery; and two
 among them have succeeded well enough to justify my
 publishing them.  The first consists in mixing the earth
 of  Murviel in  water,  and dipping the pottery  therein:
 this done,  they are suffered to dry ; after which they are
 plunged into a  second water, in which  levigated green
 glass is mixed.   This covering of vitreous powder fuses
 with the clay of Murviel; and the result is a very smooth,
 very white, and very cheap glazing.
   The second  method consists in immersing the dried
 pottery into a strong solution of sea salt,  and afterwards
 baking them.  The trial which I have made  in  my fur-
 naces gives me reason to expect that this method may be
 used in large works.
   I have likewise obtained a very black glazing, by  ex-
 posing pottery strongly heated to the  fumes  of sea-coal.
 I have coated several vessels in this manner, by throwing
 a large quantity of coal in powder into a  furnace wherein
 the pottery was ignited to whiteness.   The effect is  still
 more complete  when the chimneys or tubes of aspiration
 of the  furnace  are at that moment closed, and kept so for
 some minutes.
   I have given an account of all these circumstances, and
 many others, in a work presented to the Royal Society of
 Sciences of Montpellier; in which I have proved, from
 the results  of my experiments in the large way,  that the
 best mixture of our own earths is capable of affording us
 the most beautiful and finest pottery of every kind.
  2. Fayence*.  This does not differ from  the pottery
 we have here spoken of,  except in the degree of fineness
of the earths used for this basis, and the nature of its co-
 vering or glaze.
  The glazing  of  fayence is  nothing else,   as  is well
 known, but glass rendered opaque by means of the oxide
of tin.  It  is the glass called Enamel.                *
  To  make the  fine white  enamel of the potters,  one
hundred pounds of lead,  thirty of tin, ten of  marine salt,
* Distinguished by us by the name of Delft Ware.  T.. 
EARTHY MIXTURES.   POTTERY.        265
and twelve of purified potash, are calcined together. This
mixture,  after calcination and fusion, produces a beauti-
ful enamel,  which is applied in the  same manner  as  the
glaze before spoken of.
   Bernard de Palissy  excelled in  the  art  of fayencery;
and it is to  him that we are indebted for  our  first  acqui-
sitions in this manufacture.*

   * I cannot resist my inclination to insert in this place a few  circum-
stances of the life of this great but unfortunate man, who lived in the
15th century.  He was a native of the diocese of  Agen, ana his first
employment was that of surveyor or  draftsman of plans : but his
taste for natural history led him  to abandon this employment;  and
he travelled for instruction over the whole kingdom, and Lower Ger-
many.  An accidental circumstance tlirew into his  hands a cup of
enamelled pottery ; and, from that time, his whole time and fortune
were taken up  in experiments on enamels.   Nothing can  be more
interesting than the narrative which he himself has  given of his la-
bours.  He exhibits himself building and rebuilding his  furnaces ;
always on the eve of success; worn out by labour and misfortune;
the derision of  the public ; the object  of the  angry remonstrances
of his wife ; and reduced to burn his furniture, and even  the wood-
work of his house, to keep his furnace going.  His workman pres-
ses him for money: he strips himself, and  gives him his  clothes.
But at length, by dint of indefatigable labour, constancy and genius,
he arrived at the desired degree of perfection ; which gained him
the esteem and consideration of the greatest men  of  his age.   He
was the first who formed a collection of natural history at  Paris,  and
even gave lectures on that science ; receiving half a crown from each
of his auditors,  under the obligation of returning it fourfold if  any
thing he taught should prove false. • The  high reputation he ac-
quired, and the obligations under which his  countrymen stood in-
debted to him,  were not sufficient to "defend him from the persecu-
tions of the league ; for Matthew De  Launay, <one of the  greatest
fanatics,  caused him to be dragged to the bastile at the age of ninety
years.  He signalized himself in his prison by acts of firmness  and
heroism.   Henry the Third visited liim,  and represented his situa-
tion in these words : " My good man,  if you cannot reconcile your-
self to the matter of religion, I shall be  compelled to leave you in
the hands of my enemies."—Palissy answered, "  Sire, I was  per-
fectly ready to surrender my life for the glory of GOD   If this ac-
tion could have been accompanied with«ny regret,  certainly it must
have vanished after hearing the great King of i;ranee say, lam comr
pelltd.  This, sire,  is a situation to which neither yourself, nor those
who force  you to act contrary to  your own disposition, can  ever re-
duce me ;  because I am prepared for  death; and  because neither
your whole people, nor your Majesty,  possess the power  of forcing
a  simple potter to bend his knee before images."—Bernard de  Pa-
lissy was the first who affirmed that calcareous  mountains  are  th$
                              LI 
EARTHY MIXTURES.  PORCELAIN.
   3. The finest pottery is known by the name of Porce-
 lain; it ought to be white, transparent, and of a fine grain.
   The first porcelains were  manufactured in Japan  and
 China.
   The celebrated Reaumur first undertook  a capital se-
 ries of  experiments to  imitate these potteries:  but,  de-
 ceived by the semi-transparence and vitreous  appearance
 of porcelain, he imagined it  to be a semi-vitrification,  and
 attended only to the means of stopping the process of vi-
 trification at a certain stage of its effect,  or of causing it
 to become reversed.  He succeeded in his undertaking,
 by  filling bottles with sand  and gypsum,  and exposing
 them to a potter's furnace.   I have likeAvise produced the
 same effect by a very different process, though dependent
 on  the same theory.  When  I  concentrate my oil  of
 vitriol in the green glass of our manufacture, that  part of
 the retort which is continually struck by the  rising oil of
 vitriol becomes white, and loses its transparence.  This
 phenomenon constantly takes place, whenever the fire is
 raised somewhat more than  usual.  The retort preserves
 its form ; but all its alkali is extracted, and there remains.
 only the quartzose principle  of a beautiful white  colour,
 somewhat cracked like the porcelain of Japan. As the de-
 composition commences at the interior surface, which is im-
 mediately acted on by the vapours,  this  surface is frequent-
 ly rendered white, and discoloured;  while the exterior sur-
 face remains  perfectly  vitreous, and exhibits a  striking
 contrast.  For,  when the interior surface of the  glass is
 inspected,  it presents a white covering applied against a
 surface of  glass;  forming, by the  union  of both, a thick-
 ness no greater than that of which retorts are usually
 made.
  Father  Dentrecolles  sent  from China the substances
 used  in the fabrication of porcelain: they are known  by
the names  of Kaolin and Petunze.  Similar substances

 remains of shells.  He has exhibited such a degree  of intelligence
 and sagacity in all his writings, that he deserves to be placed among
 those great men who are an ornament  to our nation.  The  very
 form of his works exhibits a proof of original genius.  They  con-
 sist  of dialogues between Theory and Practice.  Practice is always
the instructor; and Theory is represented as a scholar, proud of his
 own understanding, but indocile and ignorant. 
           EARTHY  MIXTURES.   PORCELAIN.      267

 were soon found in France ;  and our porcelain  manufac-
 tories, in a short time, equalled  the  most beautiful  pro-
 ductions  of this kind, and  even exceeded  them  in the
 beauty of design and figure.   The manufactory of Seves
 is at present, without contradiction, the first in the world.
 Nothing can equal the beauty of its paintings, the regu-
 larity  of  design, and the  elegance of form, which are
 given to the vessels produced in  this manufactory.
   Four principal operations may be distinguished  in the
 manufacture of porcelain.—1.  The preparation, the mix-
 ture of earths, and the working of the paste.   2.  The first
 baking, which forms  the biscuit.   S. The application and
 fusion of the glaze and covering.  4.  The  art of paint-
 ing, which demands  a third baking,  in order that the co-
 lours may be better combined, fused,  and amalgamated
 with the glaze.
   I have myself made very beautiful porcelain with the
 kaolin, which is found in veins in the granite of St, Jean
 de Gardonenque, and the  field spar  so common in our
mountains of Cevennes.
   The quantity of porcelain wiiich is  made in China  is
 immense.   There are five hundred furnaces, and near a
 million of men, employed at King-to-ching, a province
 of Kian-si.
   Our clays possess other advantages likewise:  they serve
 in the fulling-mills to clean and  full piece  goods.  The
 best fuller's earth is soft and soapy.
   The name of tobacco-pipe clay is given to  a white clay,
 which preserves its whiteness in the fire, and resists a vi-
 olent heat.
   The scaled earths,  or terra? sigillataj, are clays upon
which superstition has bestowed chimerical virtues.  They
are impressed with a  seal,  for  the purpose  of deceiving
the public with greater certainty and effrontery.
   Almost all the marls, more especially those which are
found in strata, appear to me  to be composed of the same
principles.  Much variation prevails with respect to the
proportion of those constituent principles,  and more es-
 pecially with regard to the clay which predominates.*

  * A variety of good clays are found in the  United State9.  Ex-
cellent porcelain earth is met with on the banks o,f the Delaware, 
268
EARTHY MIXTURES.   MARLES.   MICA.
                      SPECIES II.

      Alumine,  Silex, Pure Magnesia, and Iron.

   Mica, which results from the mixture of these princi-
ples, has been improperly  confounded with talk.  Mica
is soft to the touch, but not greasy like talk'.   It possesses
in general  a more brilliant and less earthy colour,  if  I
may use these expressions.
   The most usual colour of mica is white or yellow,  in-
clining to red; but it has been found of a greenish, red,
brown,  and other colours.
   Its texture likewise varies:  it is  scaly,  lamellated, or
striated.
   It sometimes exhibits the form of a segment of an hex-
agonal prism.
   It is usually found mixed with feld spar, quartz, schorl,
he.   It almost always exists in the primitive rocks.   Its
specific gravity is from 2.535 to 3.000 when charged with
iron.—Kirwan.
   The colourless mica is  infusible.   It is  only partially
soluble in soda, in which it becomes divided with effer-
vescence :  it fuses in the borate of soda, and in the phos-
phate of urine,  with scarcely any effervescence.
   The coloured micas are  fusible.—See De Saussure.
   The fragments of  mica are employed,  under the name
of Cats Gold or Silver, according to the colour, as  a sand
for drying ink upon paper.
   Its yellow colour, which considerably resembles  that of
gold,  often  deceives the ignorant, who suppose that they
have discovered a mine of  this precious metal when they
find a few pieces of this stone.

above and below Philadelphia,  and  in Maryland near: Hagerstown,
at the foot of the   Ketocton  mountain.  China of a fine quality
was made in Philadelphia before  the revolutionary war.  Most of
our clays contain iron ; hence  they  burn  of a yellow and  red co-
lour.   Bricks for furnaces, or fire bricks, are manufactured from
the porcelain earth of the Delaware,  mixed with  decomposed  gra-
nite, containing a large portion of mica,  found near Gray's ferry on
the Schuylkill;  and crucibles for glass houses are made of the same
earth,  and old burnt crucibles,  in coarse powder.—Am. Ed. 
        EARTHY MIXTURES*  HORN-BLENDE.     269

  Mr. Kirwan obtained from one hundred parts of colour-
less mica, thirty-eight silex, twenty-eight alumine, twenty
magnesia, and fourteen  oxide of iron.
                      SPECIES III.

      Alumine,  Silex, Magnesia, Lime, and Iron.

  The mixture  of these principles forms the horn-stone,
or horn-blende of the Germans.   This stone has a close
grain, is difficultly pulverized, and  is slightiy flattened un-
der the hammer.
  Its colour varies, which is either black or of a greenish
grey;  and  its texture is in  general either lamellated or
striated.
   Its general characters are,  partial  solubility  in  acids
without effervescence;  a degree of hardness which never
amounts to  that of affording fire with the steel;  a specific
gravity never less than 2.66,  and  frequently as high as
3.88;  a strong earthy smell, which it emits when breathed
upon, or is  moistened with hot  water; a tenacity under
the pestle, &c.—See Kirwan, who distinguishes two va-
rieties.*
                     VARIETY I.

   Black Horn-stone, Lapis Corneus Nitens Wallerii.

  Its texture is either lamellated or grained.  In the first
case it is sometimes so soft  as to be capable of being
scratched with the nail.  Its  surface is  frequently of a
shining, greasy appearance;  and its specific gravity is from
3.6 to 3.88.
  Mr. Kirwan found that the lamellated sort contains thir-
ty-seven parts silex, twenly-two clay, sixteen magnesia,
two lime, and twenty-three oxide of iron.


  * Horn-blende of several varieties is found  in the granite of the
United States.—Am.Ed. 
270        EARTHY MIXTURES.   SLATE.
                     VARIETY II.

         Horn-stone of a greenish grey Colour.

  This variety is either of a granulated or striated texture.
Mr.  Kirwan found its specific gravity to  be 2.683; it  is
harder than the preceding.
  The pale greenish hone is of this  quality.  Its grain is
close;  it emits an earthy smell, does not effervesce with
acids,  nor strike fire with steel.   It contains, according to
Kirwan, sixty-five parts of silex to the hundred, and its
specific gravity is  6.664.


                     SPECIES IV.

 Alumine, Silex,  Carbonate of Magnesia, and of Lime
                      with Iron.

  This species, which comprehends the slate or schistus,
does not appear to differ essentially  from the preceding,
since  its principles are the same, and there is no  other
difference excepting what depends on the state of the lime
and magnesia; which in this last effervesces slightly with
acids,  according to Kirwan.
  The slate is an  argillaceous stone, whose principal cha-
racter  is that of being divisible into very thin plates, capa-
ble of being wrought, and of receiving a certain polish.
  The colour of the slate is blue, of several degrees of in^
tensity;  but this colour varies,  and exhibits the following
shades.


                      VARIETY I.

                Blueish Purple Slate.

  This is brittle,  and of  a lamellated texture;  does not
give fire with the  steel;  its specific gravity is 2.876; it af-
fords a very  clear and silvery sound, when divided into 
EARTHY  MIXTURES.   SLATE.
271
plates of an uniform thickness;  it slightly effervesces with
acids when it is reduced into powder, but not else.
   It forms black scoriae  in a strong fire.  Soda assists its
fusion, and it is fused still more easily with the borate of

   From one hundred grains of this slate Mr. Kirwan ob-
tained forty-six silex, twenty-six alumine, eight magnesia,
four carbonate of lime, and fourteen iron.



                       VARIETY II.

                       Black  Slate.

    This receives a considerable fine polish when rubbed.
 The powder which is detached is white,  and  slightly ef-
 fervesces with acids.*


                        VARIETY III.

                        Blue  Slate.

    The blue slate  contains  less  iron  than the  first variety.
 It is usually hard, and of a very fine grain.

    * Mr. Drayton informs us that slate of an excellent quality, is
 found near the  head waters of Lynch's creek, in South-Carolina.
 There are also  immense quantities of it in the township of Rhine-
 beck, in Dutchess county,  state of New-York.  A quarry of it has
 also been discovered in the county of Wayne, Pennsylvania  It
 is on the banks  of the Delaware,  within three hundred yards of the
 river, and about seventy-five miles from Philadelphia.  1 he.rock ap-
 nears on the surface of the  ground, and quarrys so easily, that plates
 several feet square have  scaled off.  This slate is much thinner
 than that of  New-York, and equal to any  that has been imported.
 Extensive use is now made of it in Philadelphia, for covering houses,
  as the  expense is only a trifle more than that of a  shingle roof—
  (MeaLfs account of the minerals of the United States, in Wonders
  of Nature and Art,  vol. xiv. p. 120.)
    It is also found in Pennsylvania, on the river Susquehanna, and
  near Frederick-town, in Maryland.  The Mohawk river, at the falls
  of Cohoos,  runs over an immense bed of slate.—Am. Ea. 
272
EARTHY MIXTURES.
SLATE.
                    VARIETY IV.

            Slate of a Pale White Colour.

  It is less martial than the other varieties, and is more
difficultly vitrified.
  Slates are used to form tablets, and to cover the roofs
of houses.
                      SPECIES V.

Alumine, Silex, Pyrites or Sulphure of Iron and Carbo-
            nate of Lime and of Magnesia.

   The schistus which results from  this combination is
known by the name of Pyritous Schistus.
   The pyrites are sometimes dispersed in the mass, in the
form of cubical crystals.   Sometimes they are discovered
only by analysis, or by the spontaneous decomposition of
the stone.
   The mountains  which afford these schisti appear to me
to be marine depositions.  Impressions of leaves, of fishes,
and other characters, are frequently observed, which leaves
no doubt of their origin.
   The pyrites soon effloresce when the concurrence of air
and water assists their decomposition;  and  the  results
then are sulphuric  salts, with bases of magnesia, alumine,
iron  and lime.   When the sulphate of alumine  predomi-
nates, it is called aluminous schistus.  Most of  the alum
ores wrought in Europe are of this nature. We have seve-
ral in Provence which might be wrought;  the schisti  of
Vebron in the Gevandan, those of Curvalle in the Albi-
geois, afford much alum by their decomposition.
   When the magnesian principle prevails, the efflorescence
consists of Epsom salt.  I have discovered a mountain of
this kind  in  Rouergue,  in the neighbourhood of Saint
Michael.
   These efflorescences of alum or Epsom salt are always
more or less abundantly mixed with the sulphates of iron 
EARTHY MIXTURES.   SLATE.          273
and of lime; because the sulphuric acid, which is  formed
by the decomposition of the pyrites, attacks and dissolves
all the principles contained in the schistus.
  The decomposition of these  pyrites may be hastened
by exposure to air,  calcination, he.


                     SPECIES VI.

Alumine, Silex, the Carbonates of Lime and of Magne-
       sia, the Sulphure  of Iron, and Bitumen.

  This schistus does not differ from the foregoing,  except.
ing in consequence of its being impregnated with bitumen.
It is usually of a black colour, which it owes to its bitu-
minous principle.   Its consistence is various; it is some-
times divisible in flakes, and its surface  is either  smooth
or rugged.
   These are the schisti wjiich usually form the focus  of
volcanos.  When their decomposition is favoured by air
or water, a prodigious heat is excited, hydrogenous gas is
produced, which exerts itself against the surrounding ob-
stacles, and takes fire when it comes in contact with the
air.   It is this intestine labour which occasions the shocks
and tremulous agitations that precede the eruptions of vol-
canos.   The action of volcanos must be more lasting and
terrible, in proportion as the quantity of  aliment  and the
focus  are the  more considerable.
   We might, in strictness,  place the pit.coals here,  as
they do not differ from this schistus but in their  greater
abundance of the bituminous principle.  We daily  observe
spontaneous inflammation to take place  in heaps of pyri-
tous coal, and the same effect happens  even in  the midst
of the veins which are wrought.   Several examples of this
may be pointed out in the kingdom  of France.   There
even exists at Cransac in Rouergue a true burning volca-
no.  The mountain which contains the coal is prodigiously*
hot, and flames are perceived from time to time on  its sum-
mit, which issue from its bowels.  All  these phenomena
depend on the same cause; and  from the small  artificial
volcano of Lemery, to the terrible eruptions of Vesuvius,
                          M m 
274       EARTHY MIXTURES.   ZEOLITE.

there is no other difference than what consists in the mag-
nitude of the cause.
  When the earthy and metallic principles  which form
the basis of bituminous schisti, are strongly  heated, and
almost vitrified by the fire  which  produces their  decom-
position, they constitute volcanic  products.

                     SPECIES VII.

          Alumine, Silex, Lime, and JVater.

  This stone which is called Zeolite, was  unknown  to
mineralogists before the celebrated Cronstedt gave a de-
scription of it.
  It is usually of a semi-transparent white ; but this co-
lour is sometimes altered by metallic mixtures, and then
it assumes all kinds of tinges.
  The name of Zeolite has been given to it on  account
of its property of forming  a jelly with acids.   This pro-
perty has even been considered as exclusive  and charac-
teristic.   But Mr. Swab has very justly observed, in the
year 1758, that all zeolites do not possess this  property;
and Mr. Pelletier has proved in the twentieth volume  of
the Journal de Physique  that this property is not even pe-
culiar to zeolites.
  The existence of zeolites in certain lavas has  induced
some naturalists to consider them as produced by the  de-
composition of volcanic earths.
  The most beautiful zeolites come to us from the islands
of Ferroe near Iceland.  The form of this stone is  con-
stant.   The radii  which compose it diverge as it were
from a central point, and are  disposed after the manner
of a fan.   The radius which terminates at the  external
surface,  is found to exhibit a trihedral or tetraliedral pyra-
mid.
.  The white zeolite affects two principal forms, the cube,
and the tetraliedral prism, sometimes flattened,  and termi-
nated by an obtuse tetrahedral pyramid.
  Its specific gravity is from 2.1  to 3.15.
  The  zeolite,  exposed to a strong heat, dilates,  and
swells more or less, according to the proportion of water 
EARTHY MIXTURES.   GEMS.         275
it contains, and at length melts into a porous scoria. Soda
fuses with it with effervescence ; the borate of soda dis-
solves it more  difficultly;  and  the  phosphates of urine
have scarcely any action upon it.
  Bergmann obtained from one  hundred parts of the red
zeolite of Adelfort, 83 silex,  9.5 alumine, 6.5 pure lime,
and 4 water.—Letters on Iceland, p. 370.
  The white zeolite of Ferroe contains, according to Pel-
letier,  fifty silex, twenty alumine, eight lime, and twenty-
two water.—Journal de Physique, t. xx.
  Meyer obtained  from a  radiated zeolite, 51.33 silex,
17.5 alumine,  6.66 lime, 17.5 water.
  Mr. Kirwan rightly observes,  that the crystallized spe-
cies contain more water than the others.*
                      GENUS  V.

                  Siliceous  Mixtures.

  We shall place in this genus  all the stones which  give
fire with the steel.
                       SPECIES I.

  Silex, Alumine, Lime, and Iron intimately combined.

  The mixture of these several earths forms the precious
stones or gems.  All  the varieties of gems depend  on
their colour,  hardness,  brilliancy, weight,  the proportion
of their  constituent parts, arid then more or less intimate
combination.
  The  numerous  experiments of the celebrated Berg-
mann on precious stones, have thrown the greatest  light
on their nature and composition.  The analyses of Messrs.
Gerhard, Achard, &c.  by exhibiting  a strict identity  of

  * Dr. Mitchell informs us, that zeolites have  been discovered at
Hobocken, New-Jersey, filling up the veins in the rocks of Stell-
stein and Jade which abound in that neighbourhood. Dr. Barton tells
us that he has found zeolite, imbedded in crystallized basaltes, near
Heading, Pennsylvania.—Am. Ed. 
276
EARTHY MIXTURES.   GEMS.
principles, have confirmed to us the results of the famous
Swedish chemist;  and it appears that no reasonable doubt
can now be formed against those principles.
  As gems or precious stones are  distinguished in com-
merce by their colour,  we shall preserve  this established
distinction.
                      DIVISION I.

 Red Gems or Precious Stones—the Ruby,  Garnet, &c.

    1.  The ruby is a precious stone of a fiery red colour,
 electrical by friction, giving fire with the steel, the most
 ponderous and the hardest of precious stones.   It crystal-
 lizes in long hexahedral pyramids  applied base to base,
 without an intermediate prism.
    Its specific gravity is from 3.18 to 4.283.   It is not vi-
 trified in the fire without addition;  and even  resists the
 action of the  burning mirror.   Flame urged by vital air
 easily fuses it.  It does not lose its colour at the degree
 of heat which is sufficient to melt  iron.  The  borate of
 soda and the phosphates of urine fuse it.
   One hundred parts of ruby contain, according to Berg-
 mann, forty alumine,  thirty, nine silex, nine lime, and ten
 iron.
   The lapidaries, with whom hardness and transparency
 are the principal  characters of stones, distinguish  riibies
 of different colours; and the inhabitants of Pegu, who
 consider the modifications of the colouring principle as
 different degrees of maturity, confound the topaz, and the
 sapphire under the name of rubies, of which they make
 three varieties.
   The name of Spinelle ruby, or Balais ruby, is given
 to the same kind of stone, accordingly as its colour is of
 a  pale or  a deep red.   This ruby crystallizes in octahe-
 drons, and has a less specific gravity than the oriental ruby.
   2.  The garnet^ is transparent when it is not overloaded
 with iron.   It is in general obedient to the  magnet, and
of a yellowish red.   The forms of the garnet appear to
be derived from the rhomboidal parallelopiped,  terminat-
ing in  six equal rhombuses, 
             EARTHY MIXTURES.   GEMS.         277

   They vary prodigiously in  colour, and these  varieties
are—1.  The red,  or the carbuncle of Theophrastus,
according to Hill: it has a deep red colour.  2. The Sy-
rian garnet, of a  deep red slightly tinged with yellow.
3. The violet garnet,  of a beautiful red mixed with vio-
let.
   All the garnets, whether denominated oriental  or occi-
dental,  rank in one of these three classes.
   Garnets change in the fire into an enamel of a blackish
red.  They are strongly attacked by the  borate  of soda,
and the phosphates of urine.
   Garnet is found in small grains in sand stone (gres) or
in schistus.
   The texture of the garnet is lamellated, and its fracture
vitreous.
   Its hardness is inferior to that of other gems, but it ex-
ceeds that of rock crystal.
   Its specific gravity is from 3.6 to 4.188.
   One  hundred parts  of garnet contain, according to Mr.
Achard, 48.3 silex, 30 clay, 11.6 lime, 10 iron.
   They sometimes contain tin,  or even lead; but this  is
seldom. —Bergmann. *

                      DIVISION II.

Yellow  Gems or Precious Stones—the Topaz, the Hya-
                      cinth,  &c.

   1. The topaz is of  a gold colour.   We are acquainted
with two principal varieties :  the occidental or Brazilian
topaz, which has the beautiful deep yellow colour of gold;
and the oriental,  wrhose colour  is lighter.   The  Saxon
topaz resembles the  latter.
   The oriental topaz  loses  neither  its  colour  nor  its
transparency in the porcelain furnace.  The Brazilian to-
paz loses  its polish, its hardness, and  its  transparency,
but without melting.
   The oriental topaz affects the octahedral form.

  * Garnets are found  in Georgia,  Pennsylvania, and many of the
other states.  Some of  them weigh four ounces.—Am. Ed. 
278
EARTHY MIXTURES.   GEMS.
  The Brazilian  topaz  crystallizes in rhomboidal tetra-
liedral prisms, grooved longitudinally.   They are termi-
nated by two tetraliedral pyramids with smooth triangular
faces.
  The Saxon topaz  exhibits long suboctahedral prisms,
terminated by hexahedral pyramids more  or less trun-
cated at their base.
  The specific gravity of the oriental topaz is to that of
water as 40,106 to 10,000; that of the Brazilian topaz is
as 35,365 to 10,000.—See Brisson.
  The analysis of one hundred parts of topaz  afforded
Bergmann forty-six clay, thirty-nine silex, eight carbonate
of lime, and six iron.*
  2.  The oriental hyacinth is of a reddish yelow colour.
  It is usually crystallized in the form  of a  rectangular
tetrahedral prism, terminated by two quadrangular pyra-
mids with rhombic faces.
  It loses the brilliancy of its colours by the  fire.  M.
Mongez considers it as  infusible by the blow-pipe.   Mr.
Achard affirms that he fused it in a wind furnace.
  One hundred parts afforded  Bergmann forty  alumine,
twenty-five silex, twenty carbonate of lime, and thirteen
iron.   That of which Mr. Achard has given the analysis,
contained 41.33  alumine, 21.66 silex, 20 carbonate of
lime, 13.33 iron.
  Hyacinths are found in Poland, in Bohemia, in Saxo-
ny, Velay,  &c.
  The hyacinth, rendered white by fire, is known by the
name of Jargon.  According to  Mr.  Lavoisier, the hya-
cinth of  Puy in Velay becomes  white  in fire  urged by
vital air.
  Its specific gravity, compared with that of water, is as
36,873 to 10,000.—See Brisson.

  * The topaz has been found in large masses in Pennsylvania and
in Virginia.—Am.  Ed. 
EARTHY MIXTURES.  GEMS.         279
                        DIVISION III.

     Green Gems—the Emerald, Chrysolite, Beryl,  £s?r.

      1.  The Peruvian emerald is of a green colour, electri-
   cal by friction, and crystallized in  hexahedral prisms,
   truncated flat at each extremity.
      The jaspers, or green schorles,  which are called prase
   or mother emerald, have often been confounded with the
   emerald.
      Crystals of emeralds are  frequently found  inserted in
   the gangues of quartz, and even  of spar.
      According to Mr.  Sage, the more transparent emeralds
   are, the less their 'colour  is changed in the fire.   They
   become opaque, and of a greenish white.   There are some
   which are reduced to enamel at their surface.
      Mr. Darcet affirms, that in his experiments the emerald
   lost its transparency, and most of its colour, but that its
   form was not changed.   In the experiments at Vienna
   in Austria, the emerald melted in twenty-four hours;  and
   at  Florence  it was speedily fused by the burning mirror.
   Mr. De Saussure fused it by the blow-pipe into a com-
   pact grey glass; and Mr. Lavoisier, with a stream of vi.
   tal air, fused it into an opaque milky bubble, whose inter-
   nahpart wras greenish.
      Its  specific gravity, compared with that of  water, is in
   the proportion of  27,755 to 10,000.
      One hundred parts afforded Bergmann sixty  alumine,
   twenty-four silex, eight lime, six iron.
      Achard obtained 60 alumine,  21.26  silex, 8.33 lime,
   and 5 iron.
      The emeralds which come from  America are called oc-
*   cidental.   Peru and the Brazils afford the most beautiful:
   they may be distinguished by the colour;  that of Pern is
   of a satin colour or appearance; the colour of the Bra-
    zilian is less lively.
      The  emerald  is the  softest  of gems,  and  may  be
   scratched by the topaz, the sapphire, &c*

      * Mr. Jefferson informs us that an emerald was once found in Vir-
   ginia.  Dr. Seybert  has discovered them at Chesnut-hill, ten miles 
280          EARTHY  MIXTURES.   GEMS.
   2.  The chrysolite  or peridot  is  of a green colour,
slightly inclining to yellow.
   Its form is that  of  a hexahedral pyramid with unequal
sides, frequently striated, and terminating in two hexahe-
dral pyramids.
   Mr.  Sage affirms that this stone suffers no alteration in
the most violent heat, its colour not being so much as al-
tered: and the same chemist pretends that Wallerius  did
not operate on a true chrysolite, because he affirms that it
lost its colour.  Messrs. Lavoisier and Ehrmann fused it
into a white, dirty, dull-coloured glass,  by the assistance
of vital air.
   The  specific gravity of the  Brazilian  chrysolite  is in
proportion to that of water as  26,923 to 10,000.—Bris-
son.
   Masses of granulated chrysolite of various shades of
green colour are found in  the prismatic basaltes, and in
several other volcanic products.
   These chrysolites are common in die  volcanos of  our
province.   Mr. Sage received from Auvergne an  hexa-
gonal prism six inches in diameter, formed  by the  union
of chrysolites of different colours.
   3.  The beryl, or aqua marina, is of a very blueish green.
   The  Saxon beryl, as well as that  of Siberia, sent to
Mr.  Sage by Mr. Pallas,  exhibits hexahedral, striated,
truncated prisms, of a lamellated  texture.
   The pure beryl  decrepitates in the fire, loses  its  trans-
parence, and is fusible by the blow-pipe.
   Its specific gravity, in proportion to water, is as 35,489
to 10,000, for the  oriental  aqua  marina; and  27,227 to
10,000, for the occidental.—Brisson.

from Philadelphia, and in the neighbourhood of Chester.  I found
one on the  banks of the Schuylkill, exactly resembling the beryl of
Siberia.  It is transparent, and of a green colour.  Dr. Chalmer's
in his  account of South-Carolina,  says, he has seen emeralds that
were brought from the country ef the Cherokees, which when cut
and polished fall nothing short of  those  which  were imported  from
India in lustre.
  The emeralds of America, generally, are similar to those of Li-
moge in France.  They are not of  a quality suited for  ornaments,
but may prove serviceable to the chemists, by affording glucine.
—Am. Ed. 
             EARTHY MIXTURES.  GfiMS,         281

  A  blue aqua  marina,  in long,  flattened, tetrahedral
prisms, grooved longitudinally, and united sideways,  is
found among the granites of Spain,  and on the  declivity
of Saint Symphorien,  near  Lyon.  This stone is very
common at Baltimore in America.
                    DIVISION IV.

               Blue Gems-*-Sapphire.

  The colour of the sapphire is a sky-blue.   The sap-
phires of the brook d'Expailly have a green tinge, and
change in the fire in the same manner as those of the Bra-
zils; whereas the oriental sapphire is not changed in our
ordinary furnaces.   Mr. Ehrmann caused the clear ori-
ental sapphire, and of a perfect blue, to run into an opaque
white globule by fire excited by a stream of oxigene gas.
  The experiments of  Messrs. Achard,  Sage, D'Arcet,
Ehrmann, Lavoisier, Geyx, Quist,  &c. exhibit a variety
of results in the analyses of gems by fire, which can be at-
tributed only to the manner in which they applied it; and
more especially to the very variable nature  of the  stones
upon which they made their experiments.
  The oriental sapphire, and that of Puy, have the form
of two very long hexahedral pyramids joined and opposed
base to base, without an intei mediate prism.  Mr. Sage
saw a sapphire in a  rhomboidal cube, or six-sided figure.
  The sapphire analyzed by Bergmann afforded him per
quintal, 58 parts alumine, 35 silex, 5 lime, and 2 iron.
  Mr. Achard obtained from his analysis 58.33 alumine,
33.33 silex, 6.66 lime,  and 3.33 iron.
  The specific gravity  of the sapphire of Puy is in pro-
portion to water as 40,769 to 10,000;  that of the  white
oriental sapphire is as 39,911;  and that of die Brazilian
sapphire is as 31,307.
Nn 
282
EARTHY MIXTURES.   CRYSTALS.
                     SPECIES II.

 Silex, sometimes pure, but oftener mixed with a very
      small quantity of Alumine, Lime, and Iron.

  This species essentially comprehends  quartz  and rock
crystal.
  The name of Quartz is given to the opaque, or irregu-
larly-figured vitrifiable stone;  and that  of Rock Crystal
to  the same  stone  crystallized.  As  the principles are
nearly the same, this circumstance naturally establishes a
division of these stones into two classes.


                     DIVISION I.

                    Rock' Crystal.

  Rock crystal is a stone which exhibits silex in a state
more nearly approaching to purity than in any other natu-
ral substance yet observed.  Mr. Gerhard has even found
specimens perfectly pure;  but one hundred parts of crys-
tal, strictly analyzed by Bergmann, afforded  him ninety-
three parts silex, six alumine,  and one lime.
  The ordinary form of rock crystal is that of an hexahe-
dral prism, terminated by pyramids of an equal number of
sides. The varieties of the several crystals may be reduc-
ed to this geometrical form.—Consult Rom6 de Lisle.
   Quartz crystallizes likewise in cubes.  This  form ex-
ists in various specimens in the cabinets of Germany; and
Mr. Macquart brought a specimen with him to France.
   The formation of this  crystal appears to be owing to
wrater, for we often find this fluid in the internal part  of
crystals;  and they are evidently formed in the  clefts and
cavities of the primitive rocks, by the concurrence of this
agent.  But hitherto we have acquired very little know-
ledge respecting the circumstances  of this operation.
   Bergmann obtained rock crystals by dissolving silex in
the fluoric acid,  and suffering it to evaporate slowly. I left
on the tables of my cabinet of mineralogy a receiver and
a retort, in which I had made  the acid of fluor;  and when 
EARTHY MIXTURES.
CRYSTALS.
283
1 had occasion, two years afterwards, to inspect this appa-
ratus, I found the receiver almost entirely corroded, and
its interior surface lined with a subtile powder, in which
thousands of rock crystals might be discerned.
  Mr. Achard informed the public that he had obtained
rock crystals by causing water impregnated with carbonic
acid to filtrate through clay.   Mr.  Magellan even pre-
sented these crystals to the  Academy at Paris;  but the
experiment, though repeated with the greatest care by se-
veral chemists  of the  capital, was not attended with the
same results.
  Since that epocha, Mr. De Morveau,  having inclosed
rock crystals with a bar of iron in a bottle filled with ga-
seous water, perceived a vitreous point fixed to the iron,
which he supposed to be a  rock crystal formed by this
operation;  so that he considers iron as a necessary  inter-
medium to enable the carbonic acid to dissolve quartz.
This consequence of Mr. De Morveau  appears to agree
with many facts which have been collected concerning the
formation of rock crystal.   We  see it formed in ochreous
earths;  and I possess ochres in my collection which pos-
sess many of these small two-pointed crystals.
  It appears to me that it is not necessary to seek  for a
solvent for silex,  in order to explain the formation of rock
crystal.  The simple division of this earth appears to me  to
be sufficient for the purpose; and I could bring numerous
facts to support this assertion.—See  the  article Crystalli-
zation.
  It is proved by the observations and experiments of Mr.
Genssane, that a quartzose gurh is formed by simple trans-
udation upon rocks of diis nature; and the same naturalist
has taken notice that,  when the gurh is worn  and deposit-
ed by water, rock-crystals are formed.  The waters which
work their way through the quartzose rocks  of the mine
of Chamillat, near Planche Les Mines in Franche-comte,
fonn quartzose stalactites to  the  roof of the works, and
even upon wood.  The extremities  of  these stalactites,
which have not yet assumed a solid consistence, are of a
granulated and crystalline substance,  easily  crushed be-
tween the fingers.
  In these cavities, called craques by the miners, a fluid
gurh is often found, and still oftener crystals ready formed. 
284      *  EARTHY MIXTURES.   CRYSTALS.

I have seen at Saint Sauveur, in the work of La Boissiere,
near Bramebiaou, several incrustations of gurh on the sides
of the gallery;  and these spreading incrustations were ter-
minated by well-formed crystals, wherever the wall over-
hung or deviated  from the perpendicular.  This gurh,
when handled, and minutely examined,  had  no other ap-
pearance than that of a siliceous paste of considerable pu-
rity.
   The same effects appear to  take place with regard  t©
rock crystals,  as  with the calcareous spars.  They are
formed whenever their principles, in  a state of  extreme
division and attenuation, are suspended by water, and de-
posited with all the circumstances which  nature requires
in order that crystallization may take place. I do not even
think it necessary to recur  to  the property  which water
possesses of sensibly dissolving silex, to  explain the for-
mation of  tiiese crystals:  and we shall refer the formation
of quartzose stalactites, agates,  &c. to the  same cause.
   Rock crystal is frequently coloured  by iron,  in which
case it assumes peculiar shades, which have been denoted
under different names.   We shall place them here as sim-
ple varieties.*


                      VARIETY I.

               Red Crystal-^-False Ruby.

   It is frequently mixed with different shades. Its colour
 is destroyed by fire,  according to Mr. D'Arcet.  It is
 found in Barbary, in Silesia, in Bohemia,  &c.
   When  it is of  a dull red,  it is called  the Hyacinth of
 Compostella.


   * Very handsome rock crystals are found in the States of Pennsyl-
 vania, Maryland, Virginia,  Kentucky, South-Carolina, and New-
 Hampshire.— Am, Ed. 
EARTHY  MIXTURES.  CRYSTALS.       285
                    VARIETY II.

         Yellow Crystal—Bohemian Topaz.

  It has sometimes a tinge inclining to yellow; its colour
is often internal only.  It is found in Velay,  near Bristol
in> England, &c.

                    VARIETY III.

           Brown Crystal—Smoky Topaz.

   This brown tinge varies from  a light brown to a deep
 black.  It is affirmed that they may be rendered clear by
 boiling them in tallow.—See Journal de Physique, t vii.
 p.  360.  '               *           .   .  ^   ;.
   It is found in Switzerland,  in Bohemia,  in Dauphiny,
 he.

                     VARIETY IV.

             Green Crystal—False  Emerald.

    This is the most scarce and the most precious  of eo»
 loured crystsls.  It is found in Saxony and Dauphiny.


                     VARIETY V.

             Blue Crystal—Water  Sapphire,

    It  does not appear to differ from the true sapphire, ex-
  cepting in being less hard.  I have  seen a specimen which
  had this colour.   It is fcund in Bohemia, in Silesia, and
  at Puy in Valay, which  has  caused it to  be  called the
  Sapphire of Puy. 
28S
EARTHY MIXTURES.   QJJARTZ.
                     VARIETY VI.

            Violet Crystal—the Amethyst.

   Its colour is more or less deep;  and it assumes a con-
siderable brilliancy by polishing.  When the crystal is only
half coloured,  it is called Prime d'Amethiste.  It  loses
its colour by a strong fire, according to Mr. D'Arcet.
This  crystal is found  of  sufficient magnitude  to  form
columns of  more  than  one foot in height,  and several
inches in diameter.


                     DIVISION IL

                        Quartz.

   Those specimens of siliceous stone in which no regular
form  appears,  and which  we here  comprehend under
the name of  Quartz, possess various degrees of trans-
parency.
   Its colour differs prodigiously ;  and it may be distin-
guished into varieties and shades perhaps more numerous
than in rock crystal itself.
   It  seldom forms entire mountains,  but  almost always
intersects, by veins more or less wide, the mountains of
primitive schistus.   At all  events,  I have made this  ob-
servation in every mountain  of this kind which I have
examined.
   The blocks of quartz, detached  by waters, are rolled,
rounded, and deposited in the form of large stones on  the
banks of rivers.  The same stones, more attenuated, form
the quartzose pebbles;  and these,  still more divided, pro-
duce  sand.
   This stone is very refractory. It is used as the basis of
bricks employed in the construction  of glass furnaces.
For this purpose it is calcined to whiteness, and in that
state thrown into water.  By this means  it may be easily
reduced to powder, and disposed  to form a' combination
widi clay. 
            EARTHY MIXTURES.   FLINTS.         287

  Quartz, well pounded,  and used in the composition of
bricks, does not equally resist the  impression of fire, if
the precaution of calcining  it,  and extinguishing  it  in
water, has not been taken.   I have obtained a  proof of
this fact, by employing the same kind of quartz in both
ways.
   This sand forms an excellent mortar with good  lime ?
and, when fused with alkalis, it produces a very  beautiful
glass.


                     SPECIES III.

   Silex, Alumine, Lime, and Iron, intimately mixed.

   The state of  fineness in the constituent principles,  and
their more or  less  intimate mixture  or amalgamation,
 appear to us to establish two divisions among the stones of
 this species.  We shall accordingly distinguish  them into
 coarser flints  and finer flints.  The first form gun flints,
 petrosilex, he.;  the second comprehend  agates, calce-
 donies, &c.

                     DIVISION I.

                  The  Coarser Flint*.

   In this place we shall arrange two stones which  appear
 to differ only by a more or  less evident degree of trans-
 parency.  The silex, or flint properly so called, is semi-
 transparent, when very thin, as for example at  its  edges:
 the petrosilex has a more opaque colour.
    1.  Gun Flint.—The gun flint gives fire with steel'. its
 colour is usually brown; and its  surface very  frequently
 exhibits a whiter colour dian the  middle,  and less  hard
 than the nucleus  of  the stone.  This external part sticks
 to the tongue,  and indicates a commencement  of decom-
 position.
   The abbe  Bacheley has  asserted  that marine produc-
 tions, such as polipiers, shells, &c. are capable of  passing
 to the state of gun  flint.—Journal de  Physique,  Supple-
 ment, 1782,  t. xxv. 
288          EARTHY MIXTURES.  FLINTS.
  The  specific  gravity of  gun flint is from 2.65 to 2.7
This stone does not melt in the fire; but it becomes white
and brittle by repeated calcinations.
  The common brown silex afforded by analysis to Mr.
Wiegleb, per quintal, eighty silex, eighteen alumine, and
two iron.
  2.  Petrosilex.—The  colour of petrosilex is a deep
blue,  or a yellowish grey.   It is interspersed  in veins
through rocks;  and from this circumstance it derives  its
name.
   Its specific gravity is from 2.59 to 2.7.
   It becomes white  in the fire like gun flint;  but it is
more fusible, for it  flows without addition.   Soda does
not totally dissolve it in the dry way;  but  the borate  of
soda, and the phosphates of  urine, dissolve it without ef-
fervescence.
   Mr. Kirwan obtained from  a petrosilex,  used in the
manufacture of porcelain by  Mr. Lauraguais,  seventy-
two parts silex, twenty-two alumine, and six lime, in the
quintal.*


                     DIVISION ll.

                  The  Finer Flints.

   This division exhibits several stones,  which, though
 distinguished by names and a  different value, are never-
 theless only  varieties of each other.   We  shall content
 ourselves with enumerating the chief.
   1. Agate.—This  is a semi-transparent silex of a very
 fine body.   Its texture is vitreous;  and its hardness such
 that  it resists the file, gives fire with the  steel, and takes
 the most beautiful polish.
   The agate when exposed to the  fire, loses its colour,
 becomes opaque, and does not melt.
   The varieties of agates are infinite.   They are founded
 on the  colour;  and they  are distinguished into cloud-
 ed, punctuated,  spotted, irised,  herborized, mossy,  he.
 See Daubenton.—The  name of Onyx is  given to  that
                                        «
   * Flint stones have  been fpund in Pennsylvania, Netf-York, and
 Virginia,—Am. Ed. 
EARTHY MlXtURES.  FLINTS.        289
kind of agate which is formed by concentric bands.  Mr.
Daubenton has proved that the agate which has received
the name  of mossy,  is  really coloured by small  mossy
vegetations.
   The purest agate is white, transparent, and  nebulous.
Such is the oriental agate, which besides appears  as if it
had protuberances or knobs on its surfaces.'
   Its specific gravity is 2.64.  I consider the agates, and
the other flints concerning which we shall proceed to treat,
as quartzose stalactites.   The sides of geodes which are
agatized,  and the strata of those flints which are found in
places where infiltrations produce rock  crystals, appear
to me conclusive in favour of this doctrine.   The  agates
have the same relation to quartz as the alabasters  to cal-
careous stones, and the theory of their formation  is  the
same.   Mr.  Dorthes  has exhibited  many proofs of this
theory respecting the formation of these stones.*
   2. The Opal.—The semi-transparent agate of a milky
whiteness, which exhibits a glittering,  changeable, inter-
nal colour of a blue,  red, and green tinge,  is known by
the name of Opal.  That which  comes  from  Hungary
has a kind  of greyish  clay  for its  gangue.  The  most
beautiful opal is the oriental opal;  sometimes called  the
spangled opal, because its colours appear like equal spots
distributed over its whole surface.  These opals have re-
ceived various names,  according to the colours they  re-
flect.
   The chatoyant stones,  or such as vary their colour ac-
cording to the position of the light, and  the  eye of  the
observer,  are varieties of the opal.   Such are the girasol,
die cat's eye, the fish's eye.
   The reflected rays of the girasol are weak, blueish, and
mixed with an orange yellow.  This stone has been found
in the lead mines of Chatelaudren in Brittany.   The most
obvious character of the girasol is,  that it exhibits  in its
internal part a luminous  point;  and reflects the rays of
light in whatever position it  may be  turned,  when  it is
cut into a globe or hemisphere.  The cat's eye has a point
near the middle, from which proceed, in a circle, greenish

  * The agate has been found in Virginia.—Am. Ed.
                        Oo 
290
EARTHY MIXTURES.   FLINTS.
 traces of a very lively colour.   The most beautiful stones
 of this kind are of a  grey  and mortdore  colour.  They
 come from Egypt and Arabia.
   The fish's eye does not differ from the cat's eye except-
 ing in its colour, which is blueish :  it is found at Java.
   3.  Calcedony.—The calcedony  is  a semi-transparent
 agate  of a milky Avhiteness, differing from the foregoing
 in not possessing the chatoyant property, or changeable-
 ness of colour.
   It has been  found in the mines  of Cornwall, in stalac-
 tites of singular elegance.  These calcedonies are almost
 always covered with protuberances like the stalagmites.
   The protuberances appear to be  formed  by the suc-
 cessive apposition of several strata or coatings.
   In Monte Berico,  in the territory of Vicenza, geodes
 of calcedony are found which  inclose  water.  They are
 called Enhydria.
   I possess, in the Mineralogical Cabinet of the province,
 calcedonies of Auvergne, which appear to be crystallized
 like rock-crystal.  The crystals have all the fat  and unc-
 tuous appearance of, the same  balls  which are  dispersed
 on  the rock;  but, when they are  broke, it is seen that
 the appearance arose  from a covering  of calcedony over
 the crystal of quartz.
  Mr. Bindheim analized calcedony,  and found, in the
 centenary, 83.3 silex, 11 lime, 1.6  alumine,  and a small
 quantity of iron.—Schrist. Natur.   For.  Free.  t.  hi.  p.
 429.
  Mr. Darcet  did not succeed in fusing calcedony,  but
 it lost its colour.
  Calcedony has often a  shade of blue, yellow, or red.
  Mr. De Carozy and Mr. Macquart observed in Poland
the transformation of  gypsum  to the state of calcedony.
 —See the Essai de Mineralogie par M.  Macquart, pre-
mier memoire.
  Cacholong.   The white and opaque calcedony is known
by the name of Cacholong.  Its  texture resembles that
of quartz, and it becomes white in  the fire.  This stone
is capable of a fine polish.   It is found on the banks of a
river named Cach, near  the Kalmouks of  Bucharia, in
whose language the word cholong signifies stone. 
EARTHY MIXTURES.  JASPER.        291
   An imaginary value has been given to a modification of
the cacholong, which has the property of becoming trans-
parent after having been plunged in water.  This is called
Hydrophanes, Lapis Mutabilis,   Oculus Mundi,   Mr.
Dantz brought hydrophanes to Paris, which became trans-
parent when plunged in water.
   Mr. Gerhard, on  the 28th  of August, 1777, read  to
the Academy of Berlin Observations on the Hydrophanes.
He found that this stone contained two-thirds of clay, and
one third of silex.   This celebrated naturalist affirms that
the hydrophanes was known  to Boyle, who saw  one  of
them about the size of a pea sold in London for two  hun-
dred pounds sterling.
   The hydrophanes is fusible in the fire.   Soda dissolves
it with effervescence ;  the borate of soda, and  the phos-
phates of urine, without effervescence.
   5.  Carnelian.   Sardonyx.   The carnelian is a  species
of agate, nearly transparent   It is called Carneole when
it has the  colour  of flesh.  Its hardness varies prodigi-
ously.   Those which are white or yellowish are not. suf-
ficiently hard to give fire with the  steel.  When  ignited
it loses its colour, and becomes opaque.  The most beau-
tiful  specimens resemble  the garnet.   Its specific  gravity
is from 2.-6 to 2.7.
   The sardonyx is a semi-transpi.tent silex, of an orange
colour, more or less deep.   It is knobbed like the calce-
dony ; and possesses the hardness and specific gravity of
that stone.  Its habitude in the fire resembles that of the
agate.   In the Royal Wardrobe of France there are ves-'
sels of sardonyx of  an astonishing magnitude and beauty.
The famous murrhine vases were of sardonyx.   Sage, t
ii. p. 163,
                     SPECIES IV..

              Silex, Alumine,  andiron.

  Jasper is one of the hardest stones  we are acquainted
with.   It is susceptible of the finest  polish; and its co-
lour varies prodigiously,  which has occasioned  it  to re- 
292        EARTHY MIXTURES.   TOURMALINE.

ceive the names of Sanguine Jasper, Green Jasper, Flow-
ered Jasper, &c.
  Mr. Wedgwood assured Mr. Kirwan that jasper  har-
dens in the fire without melting; and Mr. Lavoisier could
not obtain a perfect fusion by the assistance of oxigenous
gas.   The surface only becomes vitreous.
  Mr. Gerhard asserts that some species are fusible; and
Mr.  Kirwan attributes this  property to the mixture of
lime and iron which produces the fusion.
  Its excessive hardness has induced the savages  of  Ca-
nada to avail themselves of it in the fabrication  of the
heads of javelins.
  Mr. Dorthes has found, among the wrorn stones of the
Mediterranean  shore, javelin-heads  of porphyry,  jasper,
horn-stone, schorl, variolite,  &c.  probably fabricated by
the ancient inhabitants, the Gauls.
  These javelin heads are commonly known by the name
of Thunder-stones, and vare distinguished by lithologists
by the name of Ceraunites,


                      SPECIES V.

Silex, Alumine, Lime with a small portion of Magnesia^
                      and Iron.

  This species comprehends all the schorls; and most
of the volcanic products.   As the tourmaline is evidendy
nothing more than a variety of the  schorl, we shall place
it here, though analysis has  not  discovered an atom  of
magnesia in it, and the nature of its principles confounds
it with precious stones.  Moreover by placing it between
these  and the schorls, it possesses  a situation assigned to
it as well by its natural characters  as by its constituent
principles.
   I.  The Tourmaline.—This stone possesses the transpa-
rency of the  schorl.  Its appearance and fracture are vi-
treous, its texture lamellated, its hardness so considerable
as to  cut glass.  When heated to  the two-hundredth de-
gree  of Fahrenheit, it becomes electrical;  a stronger fire
deprives it of this property.  It is  fusible  by  the blow- 
            EARTHY MIXTURES.   SCHORLS.        293

 pipe, with ebullitidp: the pure tourmaline was melted in-
 to a black ^lass, in the experiments of Mr. Lavoisier.
   Tourmalines have been found in the island of Ceylon,
 in Tyrol, and in Spain.
   Its  form  is  that  of  a  nine-sided  prism,  terminated
 by two flat trihedral pyramids.   Mr. DeJoubert possesses
 one whose prism is seven inches and a half long, and ele-
 ven inches in circumference.
   The prismatic tourmaline has no electric effect but ac-
 cording to the direction of its column;  the sphere of ac-
 tivity  of the  Spanish tourmaline  is less extensive  tiian
 that of Tyrol.
  fThe valuable researches of Bergmann upon  this stone
 may be consulted in his  dissertation concerning its analy-
 sis.   Mr. Tofani has annexed a set of interesting notes to
 his translation of this work.
   The results of Bergmann's analysis exhibit its compo-
 nent parts in the following proportion :
   1. The tourmaline of Tyrol contains alumine forty-two,
 silex forty, lime twelve,  iron six.
   2.  The tourmaline of  Ceylon, alumine thirty-nine, si-
 lex thirty-seven, lime fifteen, iron nine.
   3.  The tourmaline of  Brazil,  alumine fifty, silex tiiirty-
 four,  lime eleven, iron five.
   The specific  gravity  of the  tourmaline of Ceylon  is
 30,541, that of  Spain and of Tyrol is 30,863, water being
 10,000.—See Brisson.
   II.  Schorl.  The distinct properties of schorl  are, an
 appearance of semi-vitrification, fusibility in  a moderate
 fire,  and hardness approaching to that of crystal.
  There are  few stones which exhibit a greater variety of
form or colour.
  They enter into the composition of porphyry,  of ser-
pentine, of granite, and are  very  frequentiy found with the
magnesian stones.
  We shall distinguish the schorls  into crystallized and
irregularly-shaped schorls,
  A.  All the varieties which depend upon colour may be
reduced to four. 
294
EARTHY MIXTURES.   SCHORLS.
   1. Black Schorl.—The black schorl is found chiefly in
granites.*   It has almost always the form of prisms more
Or less perfect.   The number of sides of these prisms is
various:  they are sometimes grooved; they  sometimes
terminate in trihedral obtuse pyramids, placed in contrary
directions ; in some places they are found several inches
long,   and  the union  of these prisms  frequently forms
groups of several  in  diameter.   Their black colour is
more or less deep.   When urged  by fire, they  become
resolved  into a black uniform glass of an imperfect fluidity
like paste.
   The analysis of the  black prismatic schorls  of Gevau-
dan afforded me,  per quintal, fifty-two silex, thirty-seven
alumine, five lime, three magnesia,  and three iron.
   2. Green Schorl.—This variety exhibits the same form,
and the same modifications ;  but the  most common of its
crystallizations is that  of a tetrahedral prism, terminating
in short pyramids likewise tetrahedral.
   3.  Violet Schorl.—This variety was discovered in 1781
by Mr. Schreiber,  below the grotto  of Aunis;  situated
at the  distance of one  league from Bourg D'oisan in Dau-
phiny.   Mr. De la Peyrouse likewise found it at the Peak
of Dretliz, in the Pyrenean Mountains.
   This Schorl possesses a certain degree of transparency.
It is crystallized in rhomboides; its texture is lamellated;
two of the  rhomboidal planes of each pyramid have their
faces striated parallel to each other.
   Schorl loses its colour in the fire, and one thirteenth of
its weight; it becomes of a greyish white :  and  with a
stronger degree of heat it swells up, subsides, and forms a
black  enamel.
   Its  specific gravity is 32,956, according to Brisson.
   4.  White Schorl.—This variety has been found in the
mountains of Corsica, Dauphiny,  and  the Pyrenees.  It
is of an  opaque white colour, and vitreous appearance ; and
is found in crystals on the surface of certain stones of the
nature of the lapis ollaris.   I  have  seen a layer of this
schorl between amianthus and the lapis ollaris.   fIt melts
in the fire into a white enamel.

   * Crystallized black schorl is found in the granite of the United
States.—Am. Ed. 
EARTHY MIXTURES.
VOLCANIC PRODUCTS. 295
  The analysis of this schorl from the Pyrenean Mountains
afforded me, per quintal, fifty-five parts silex, twenty-two
alumine, thirteen magnesia, and seven lime.
  B.  The schorl in connected masses nearly approaches
the jasper in its  external  characters.  It  may  be distin-
guished however by its fracture, which is of a dryer gram,
and exhibits a disposition to crystallization.  This stone
serves as the basis to several porphyries.  The vanohte of
Durance, a stone singular on account of the superstitions
to which it has given rise, is a schorl in the mass, covered
with  grains of the same nature  as the ground, but of a
clearer green.
   Mr. Dorthes has observed variolites on the coast oi our
Mediterranean sea;  and affirms that this stone in its de-
composition undergoes changes of colour which succeed
each other in the order of the solar spectrum.
    III. Volcanic Products.—The  principal products of
 volcanos are basaltes, lava, and terra pozzolana.  These
 substances are absolutely of the same nature ; but they are
 principally distinguished by the name of  Basaltes when
 their  form is regular.   When they have no determinate
 figure, they are denominated Lavas ;  and when consider-
 ably attenuated they are distinguished by the name of Ter-
 ra Pozzolana.                       .    .
    Basaltes is distinguished into the prismatic basaltes with
 a number of sides,  from three to seven; the basaltes  in
 tables and the spherical basaltes.                  .
    Lava is distinguished into compact lava,  porous lava,
 twisted lava, lava in  tears,  he.
    Several naturalists have classed the basaltes with  the
 schorls,  and some of them have assigned the same origin
 to both.  It appears nevertheless to  be generally agreed
 that basaltes is a product of fire.
    It sometimes differs from schorls m its chemical analy-
  sis,  and also in the circumstance of its not always afford-
  ing magnesian earth.
    The colour of basaltes is of a deep green,  almost con-
  stantly covered or enveloped with a ferruginous crust less
  black than the internal part.   The iron is in  the state of
  ochre.
* 
 296       EARTHY MIXTURES.  BASALTES.

   Its form is  constantly prismatic,  which is the natural
 effect of the contraction wliich it suffers in cooling.
   Basaltes is converted by fire  into a most  beautiful
 black glass.   This property,  which is admitted by every
 chemist, induced me to fuse it,  and blow it into botties.
   The attempt was perfectly successful at the glass-house
 of Mr.  Gilley of Allais, and at that of  Mr. Giral of  Ere-
 pian.   I still preserve the  first vessels which were blown
 of this substance:  they are of the most  beautiful black,
 astonishingly  light,  but  without transparency.   Encou-
 raged by this first success, I requested Mr. Castelveil, the
 proprietor  of another glass-house,  to undertake some ex-
 periments; and in consequence of various trials we suc-
 ceeded in  fabricating bottles of an olive green, in which
 the most extreme lightness, and a truly  astonishing de-
 gree  of solidity, were united.  Pounded basaltes,  soda, and
 sand, in nearly equal proportions,  formed their  composi-
 tion.   The properties of these bottles, as proved by my
 own  experiments, as well as by those  which Mr. Joly de
 Fleury, at that time comptroller-general, ordered to be
 made, render them of the greatest  value in commerce;
 and Mr. Castelveil was unable to supply the numerous or-
 ders he received.  This manufacture supported itself with
 success for twro years: but at the end of that time the su-
 periority of the bottles  ceased  to be the same ;  the ma-
 nufacturer  received the reproaches of the consumer; this
 superb  establishment gradually fell off, and was at length
 abandoned.
   Since that period I have made several  experiments  in
 the large way,  from which  I  have obtained  results that
 may be of service to such as are  desirous  of following
 this manufacture.
   I.  The nature of the combustible used in  glass-houses
 has a prodigious effect in modifying the results of experi-
 ments.  The same basaltes which  Mr.  Castelveil consi-
 dered as too refractory in his furnace heated by wood, was
 found of too fusible a nature by Mr. Giral, who was  in
 the habit of using pit-coal in his glass  works.  The for-
mer manufacturer accordingly made his glass by  adding
 soda to  the lava, whilst the  latter mixed it with a very re-
 fractory sand. 
EARTHY MIXTURES.
LAVAS.
29T
  2.  The same lava, fused without  addition,  may  be
blown in one glass-house, and not in another.  This irre-
gularity appeared to me at first  to  depend essentially  on
the  skill of the workmen; but  I have  been since con-
vinced that it is totally independent of that circumstance.
  In a furnace which is strongly heated, the fused lava
sometimes becomes fluid like water, and drops from the
iron tube as  soon  as it  is collected.   The same lava,
when fused in other fumaces will preserve a  sufficient de-
gree of  consistence to admit of being blown.  I am my-
self well assured that the lava might be wrought in  any
glass-house whatever, provided the moment was  seized
in which the paste was neither too fluid nor  too  thick to
be wrought;  but these attentions are too delicate, and too
minute, to be observed in works in the large way.
  3.  The hardest basaltes affords the most beautiful glass.
When it is contaminated  with foreign principles,  such as
the nodules of lime, the glass is brittle, and has not a suf-
ficient connexion of its parts.  This circumstance, in my
opinion, was  the  cause of the bad quality of the glass,
which produced the failure in Mr.  Castelveil's  manu-
factory.
  4. I have seen very hard basaltes interspersed with black
infusible points, insomuch that these points became enve-
loped in die vitreous paste without any perceptible altera-
tion.  The volcanic mountain of Escandorgue near Lodeve
afforded me this variety of basaltes.
  In the article Verrerie of the Encyclopedic Methodique,
may  be seen the various results which we have  obtained
with Mr. Allut, in several experiments made in  common
in the royal glass works of Bosquet and elsewhere.
  I shall conclude, from the observation which my expe-
riments have hitherto afforded—
   1.  That lava may be used as a flux in glass-houses to
diminish the  consumption of soda.   This   is the single
purpose I at that time proposed to  myself, and I have
clearly accomplished it.   1.  By the results of experiments
which have shewn that refractory sand becomes  fused in
the glass furnace by a mixture of lava.  2. By the effects
obtained in all the works in the large way,  in which  the
addition of lava permitted a diminution in the proportion
of  soda. 
-98-         EARTHY MIXTURES.   TRAPf.

   2.  It is very difficult to establish a rigorous process, ap-
plicable  to  all circumstances,  by  which  lava  may be
Wrought without addition.  My bottles into  which the
lava entered as a component part, were scarcely  known,
before it was published that they  were formed of lava
without addition ; nothing more being said to be required
than  to  fuse  the lava in order  to  form bottles.  This
strange report affected me very  little in the principle; be-
cause I had neither spoken,  written nor printed any thing
which was capable of giving authority to such an error :
and I was content to reply to all persons  who  demanded
information, by informing them that experience had taught
me that an addition of lava diminished the  proportion of
soda in the composition of glass, and that this new- prin-
ciple rendered the bottles lighter and stronger.
   3.  That the only advantage wiiich can be derived from
fusing lava without addition, is to pour it out into moulds,
to form paving stones, chimney jambs, &c.  The facility
with which it is fused by the assistance of pit-coal, would
render these works  of small expense;  and it might easily
be decorated by incrusting it with metallic  colours.
   4.  That the difference in  the nature of volcanic pro-
ducts produces such a variety in the results of their fusion,
that I consider it as impossible  to assign a constant and
invariable process,  by which the same result may infalli-
bly be obtained.  This circumstance renders it necessary
to make preliminary trials in all  cases wherein it is intend-
ed to use basaltes in the fabrication of bottles.
   The basaltes has been considered as similar to a stone
known by the name of Trapp :  it resembles it in several
essential  properties: the  colour, form, weight,  and the
nature of the component parts of each, appear to autho-
rize us in confounding them together,  as  Bergmann has
proved by the fine comparison he has made of these two
stones, in his analysis of the volcanic products of Iceland.
But this  same chemist has shewn that they differ in seve-
ral other points of view.
   The trapp exhibits no character which can give ground
to suspect that its origin is volcanic ; it is found in  Swe-
den,  in the primitive mountains, and upon strata of gra-
nite and  schistus, and sometimes even upon banks of cal-
careous stone. 
EARTHY MIXTURES.
TRAFP.
29,9
   The trapp of the mountains of Westrogothland is usu-
ally in the form of square irregular cubes; and it is  in-
debted for its  denomination to  this  resemblance to  the
steps of a stair case.  It likewise exhibits the  form of a
triangular prism, though seldom; and sometimes it  re-
sembles immense columns.
   The trapp afforded Bergmann the same principles, and
nearly in the same proportion,  as the  basaltes.   The dif-
ference is scarcely the hundredth part;  and this variation
is frequently found in pieces of the same basaltes.*


   * Basaltic stones are  found at Flour-town, about thirteen miles
from Philadelphia ; and on the Conewago hills east of the Susque-
hanna, and half a mile  east of Elizabeth-town.  At this place they
are interspersed with large masses of brechia, composed of pebbles
rounded by friction, imbedded in the red free stone of the moun*
tains.
   The following is an  account of a basaltic wall, discovered  under
the surface of the earth, in North-Carolina, in a letter from the Rev.
James Hall, A. M. to the editor  of this work, with hi-s reply.
   Near the confluence of South Yadkin and Third Creek, about four-
teen miles from Salisbury, in North-Carolina, a phenomenon of great
antiquity has been discovered, which has engaged the  attention of
the curious in that part of the state,  and which I have lately endea-
voured to explore.
   During the heavy rains which  fell in the summer of  1794, a ca-
vern of about eight feet deep was formed in  the, side of a hill,  near a
small stream of water, by the successive torrents of rain-water which
issued from an adjacent field.
   The hill  is between two and three poles in surface where the ca-
vern is formed, about the middle of which stands a subterranean wall,
composed of small stones, laid in a white cement, resembling lime
of a very fine texture.  The largest  stones,  among many hundreds
which I have examined, do not, in my opinion, exceed twelve pounds
in weight, and from that are to  be found of all  sizes down to the
weight of one ounce.
   The species of stone is what the  Irish call the black whin;  nor is
any other kind of stone to be found in the wall.
   The stones incline to an oblong, -though they  are very irregular
in their form.
   They are universally laid across the wall; and the angles of each
stone are  so fitted  by  those contiguous  to it, that it is difficult to
enter the edge of a mattock between them, although the cement has
lost its tenacious quality, and is  as moist as  the surrounding earth.
   The cement 1 have examined in not less than forty  different
places in the wall, and could not find among it any appearance of
sand or common earth, except where there has been an opportunity
of the earth mingling with it from the top of the wall. 
300
EARTHY MIXTURES.  * CHRYSOPRASE.
                       SPECIES VI.

Siltx,  Lime,  Magnesia, Iron, Copper,  and the  Fluo-
                          ric Acid.

   This combination forms the chrysoprase.   Its colour is
a semi-transparent apple green,  and it is harder than the
fusibles spars and quartz of the same  colour.

  Both  sides of the wall are plastered with the cement, so that not
a stone  has appeared when the wall was completed, supposing it to
be a work of art; and that this is the case is, in my opinion, evident
from  this circumstance ; that where the cement  was washed off
from  the surface of the wall, hundreds of small stones  appeared
within a small space, as if slipped in between the ends of the stones,
where they could not be brought  into contact, to fill up the chasms
with the cement  about them ;  and from the apparent nature  and  si-
tuation  of the materials, it  appears probable to me, that when the
wall was dry, and above ground, it was nearly as firm as a solid rock
of the same dimensions.
   The wall is about two feet thick, built in a straight line, and per-
pendicular.  It has been traced about ninety feet  down the  stream
below the cavern, and,  perhaps,  double  that distance  in  the oppo-
site direction.  That part I  did not measure.
   The  top of the wall, at an average, is between two and three
feet below  the surface of the  earth, both above  and below  the ca-
vern,  although the situation of the  ground on the two sides is very
different.
   Above the cavern the hill rises abruptly, where the wall rises with
it, and, in  a few poles,  the ground becomes almost level, the stream^
bearing considerably from the wall.
   Below the  cavern the wall runs  parallel to, and along  the de-
clivity of the hill; so that,  as far as the wall has been explored, the
end which is up the stream  is, by a horizontal  level, fifteen, per-
haps  twenty,  feet higher than the other.
   Where  the w all  bends over the hill the stones lie in a much
more detached situation than  in any  other place which I  examined,
and appear as if  the lower end had sunk when the cement was in a
state of moisture, so as to admit the stones to be drawn asunder,
rather than make any particular  chasm.
   Two  circumstances have  much excited  my curiosity respecting
the wall; one is, that it has been explored five feet lower than the
surface of  the adjacent stream, which runs not more than forty feet
distant  from the wall, without  any appearance of its termination
downwards, or of any end,  corner or opening  discovered in the dis-
tance of near three hundred feet in length where it has been traced.
The other is, that a coarse gravelly rock embraces the wall on both 
EARTHY  MIXTURES.   CHRYSOPRASE.      301
   The fire deprives it of its green colour, renders it white
and opaque, and forms by the assistance of vital air a com-
pact and milky globule.—See Ehrmann.

sides, increasing in hardness as far as the  wall has  been examined
in depth; from which I think these two facts are evident, taut, at
the time the wall was built, the adjacent stream1 had no existence in
that place ; and that, since that time, the rock has been generated.
   The wall has had so little tendency to form  a concretion with the
rock, that, as far downwards as the rock would yield  to  the mat-
tock where it was dug away, the plastering stood smooth and entire ;
and, where the rock is too  hard to be dug, and the wall was re-
moved, the cheeks of the rock which embrace the wall are as level
and smooth as the plastering against which it  rested. This, I  think,
incontestibly proves, that the rock has been formed after the wall
was constructed.
   The depth at which the wall has been  examined is supposed to
be about fourteen feet.   This I could not  exactly  ascertain, as the
wall had been demolished for near sixty feet in length.
   It is my intention,  if health permit, next  August,  to endeavour
to carry forward a further inquiry,  the result of which you may  ex
pect by the first convenient opportunity.
                        Editor's Reply.

     Sir,

  I have read your account of a supposed artificial wall, discovered
under the  surface of the earth, in North-Carolina, with great at-
tention.
  I am well satisfied, from several specimens of the  stones which
I have seen composing this wall, that it  consists of a  mineral  sub-
stance called basaltes,  and that it is a production of nature, and not
of art.
  My reasons for this opinion are as follow : ~
  The stones answer  the description of basaltes  given  by/ various
writers.  They are found of an irregular form, in prisms consisting
of several sides, and are of different sizes ; some being  so small as
to weigh no more than one ounce, while others exceed the weight
of twelve pounds.  The angles fit each other exactly like the basal-
tes,  and appear as if joined by the hand of a skilful workman.
  There is a brown ochreous  matter found upon the surfaces of
these stones, exactly like  that on some of the basaltes of other
countries.  This ochre arises from a chemical decomposition of the
stone, called by some spontaneous calcination, and by others  efflo-
rescence. 
302
EARTHY  MIXTURES.   CHRYSOPRASE,
   Mr. Achard obtained, in the quintal of  this  stone,  95
parts silex,  1.7 lime,  1.2 magnesia, 0.6 copper.

   The decomposition is owing to the iron contained in the stones,
and its calcination by air and water.*
   Fourcroy has improperly attributed the brown  crust  with which
the stones are covered, to water depositing different kinds  of  earth
between the sides of the basaltic columns  ; and in Nicholson's Che-
mical Dictionary f it is called cement with equal impropriety.  Co-
lumns of  the Giant's Causeway,says the compiler of the Dictionary,
fit accurately together, being,  in some instances, united by a strong
cement.
   That the brown crust which adheres to the stones, and  the fine
white  friable matter with which you suppose the wall has been plas-
tered, are owing to chemical decomposition, appears  evident  from
the following circumstances : If the brown ochre is carefully scraped
off from the stone,  the surface will be found to be not of so firm a
texture as' the internal part; and the white powder, brown crust, and
internal part of the stone,  are composed of the same principles,  in
nearly the same proportions.
   In some countries the basaltes are so much calcined as to fall  to
pieces on  being removed.$
   The regularity of the wall,  and the number of small stones which
appear as  if slipped in between the  ends of the stones, are no proofs
of its being a production of art.  The basaltes, in Italy, appear like
piles  of wood  of equal thickness throughout, and extend to a consi-
derable distance.
   Faujas  Saint Fond informs us that  in Scotland there is a vast ba-
saltic wall perfectly straight and upright,  eighty-nine feet long and
twenty-five feet high.  Travels, vol. ii. p. 127.
   The following account of the cave of Fingal, extracted from Gar-
net's tour through Scotland, will  shew how little  the regularity of
the wall contributes to  prove, that it is an artificial production.
   " As we  turned the southern point of the island of Staffa, the ba-
saltic columns became vastly more regular, and the view on this side
of the island was grand beyond conception : it appeared like the end
of an immense cathedral, whose massy roof was supported by stu-
pendous pillars, formed with all the regularity of art.
   Proceeding still further along the same side of the  island, we had
a view of  Fingal's cave, one of the most magnificent  sights the eye
ever beheld.   It appears  like the inside of a cathedral, of  immense
size, but  superior to any  work of art, in grandeur and sublimity,
and equal to any in regularity.
   Regularity is the only part in which art pretends to excel nature,
but here nature has shewn, that when she pleases she can set man

  • II est facile de voir quecette decomposition, cettefriabilite' dependent du fer qui
est contenu dans ces pierres,  et de son oxidation par  l'air et par l'eau.   French Ency-
clopedia, art. basaltes.
  t Ait. basaltes.                       ,
  t Histeire  Naturslle de la France Meridionale> torn, u, p. 52.  par  M. l'Abbe  Giraud
So.ula.vie. 
EARTHY  MIXTURES.   LAPIS  LAZULI..     303
                        SPECIES VII.

Silex,  the blue Fluate of Lime,  with  the  Sulphate  of
                      Lime and Iron.

   This singular combination forms the Lapis  Lazuli,  or
Azure Stone.

at nought, and make him sensible of his own littleness.   Her works
are in general distinguished by a grand  sublimity, in which she dis-
dains the similar position of parts, called by mankind regularity,
but which, in fact, may be another name, for narrowness of concep-
tion and  poverty of idea; but here in a  playful mood, she  has pro-
duced a regular piece of workmanship,  and on a scale so immense,
as to make all the temples built by the  hand of man hide  their  di-
minished heads."
   Dr. Vantroil speaking on  the same subject says—" This piece of
nature's  architecture surpasses every thing that invention, luxury
or taste, ever produced among the Greeks."
   The small stones may  have  been carried down from the surface
of the earth by rain, and deposited in  the places  where  they  are
now found.
   I do  not  suppose that the  rock which embraces the wall, and
which,  from the specimen you have shewn  me,  is  granite, was
formed after the wall, granite  being among the first formed sub-
stances in nature.   The rock has probably been burst asunder by
the wall, which is, perhaps, of volcanic origin.
   In Cronstedt's Mineralogy  there is  an account, by Mr. Latrobe.,
of a rock of granite in Upper Lusatia, which has been rent asunder
by a vein of concentric basaltes.   In Italy basaltes are often found
resting upon a bed of granite.
   That  there have been volcanos  in North-Carolina appears from
some specimens of lava sent from that part to this city.
   The following experiments were made in order to  ascertain  the
component parts of the American basaltes:
                        EXPERIMENT I.
  One hundred grains of the  solid stone  were reduced into an  im-
palpable powder, and boiled half an hour in half an  ounce of nitric
acid, diluted with one ounce of water.  The whole was placed upon
a filter,  and distilled water was added  until it  passed  through  the
filter, insipid to the taste.   The powder remaining upon the filter
was siliceous earth, and, when dry, weighed exactly fifty-eight grains.

                       EXXERIMENT  II.
   A solution of potash was added to the fluid which passed through
the filter until no precipitation took place.  The precipitated mat-
ter was  carefully wa hed in a large quantity of distilled water, and,
when dried, weighed forty grains. 
304
EARTHY MIXTURES.
LAPIS  LAZULI.
   Its  colour is of a beautiful opaque blue,  which it pre^
 serves in a strong heat,  and does not suffer any  alteration
 in this respect by the contact of air.

                        EXPERIMENT III.

   This dried precipitate was boiled half an hour in distilled vinegar,
 in order to  dissolve the lime and magnesia which it might contain.
 The vinegar was filtered and evaporated to dryness.  Diluted sul-
 phuric acid  was added to the dry matter,  in order to form selenite,
 or the sulphate of lime, and Epsom salt, or the sulphate of magne-
 sia.   Distilled water was added to separate the sulphate of magne-
 sia from the insoluble sulphate of lime.
   The  magnesia was  precipitated by a solution  of  potash, and,
 when dried, weighed three grains.

                        EXPERIMENT IV.

   That part of the  dried precipitate, mentioned in the second expe-
 riment, which was not acted upon  by the vinegar,  weighed twenty-
 nine grains.  It was dissolved in diluted nitric acid, and  a solution
 of the prussiate of potash was added until no precipitation took place.
 The prussiate of iron was separated by a filter, boiled in a solution
 of potash, washed well with distilled water, and dried, when it weigh-
 ed ten grains.

                        EXPERIMENT V.

   A solution of potash was added to the  filtered liquor of the last
 experiment, until  no  precipitation  took  place.   The precipitate,
 which was alumine, was well washed in distilled water, and, when
 dry, weighed sixteen grains.
   The  proportions of the ingredients composing the American ba-
 saltes, from these experiments, are fifty-eight  parts  of siliceous
 earth, sixteen of argillaceous,  three of magnesia,  and ten of iron,
 which,  added together, make  eighty-seven.   Counting two grains
 lost in the first experiment, and five in the other, we will have nine-
 ty-four  grains, which,  with six allowed for the lime, will make one
 hundred grains.
   One  hundred grains of the white friable matter called cement,
 and  the same quantity of the ochreous crust, were subjected to the
•same kind of experiments, and gave the  following result:

                      Silex. Alumine. Lime. Mag. Iron. Loss.
 White friable powder,   55     16      5     3     12     9
 Brown ochreous crust,    54     15      6     3     11    11
 Powdered stone,         58      16      6     3    10     7
   Upon comparing this analysis with those of Bergmann, Mongez,
 and Faujas de Saint Fond, no great difference will be found in the
 proportion of the ingredients composing the American basaltes and
 thoce of other countries. 
EARTHY MIXTURES.   FELD SPAR.       305
  The powder of this stone makes a slight  effervescence
with acids; but  after calcination it forms a jelly with
acids, without exhibiting any previous effervescence.
  The powder of this stone forms the valuable  colour
known by the name of Ultramarine.  The  price  of this
colour is proportioned to  its intensity; and its value is
accordingly least  when it is mixed  with pyrites, because
these bodies diminish the vivacity of its colour.
  This stone affords water by calcination, and when dis-
tilled with the muriate  of  ammoniac, it forms  martial
flovvvrs; which proves, according to Mr. Sage,  that  its
colour is owing to iron.
  The azure stone is fused  by a strong heat into a whitish
glass;  and by the assistance of oxigene it forms  a white
transparent  globule inclining to green, without internal
bubbles, and  not obedient to the magnet.
   The specific gravity of the  lapis lazuli  Of Siberia is
29,454.—See Brisson.
   Plates of the lapis lazuli may be  seen upon  almost all
richly decorated  altars;  it is likewise made into toys.
   Margraff obtained from  this stone calcareous earth,
gypsum,  iron, and silex.  Mr. Rinnmann has discovered
that it contains the fluoric acid.
                     SPECIES VIII.

       r Silex, Alumine, Barytes, and Magnesia.

  This stone is known by the names of Feld Spar, Rhom-
boidal Quartz,  Spathum scintillans, Petuntze.
  It very frequently forms one of the principles of gra-
nite, and the  crystals,  which  are found separate, arise
from the decomposition of this primitive rock.

     Analysis by Bergmann, Mongez, Faujas de Saint Fond:
    Silex,             52   56      46
    Argillaceous earth,  15    15      30
    Lime,            8     4      10
    Iron,              25   25       8
    Magnesia;         0    0       6

                    100  100     100
Qq 
306
EARTHY MIXTURES.  EELD  SPAR.
  The texture of feld spar is close, lamellated, and it is
less hard than quartz.
  It fuses without addition into a whitish  glass.   I have
nevertheless observed a very great variety in the feld spars,
with regard to their habitude in the fire.  That of A-
venne, which is  in  the  form  of whitish  crystals  mixed
with quartz,  afforded me a transparent glass of extreme
hardness by the  simple addition  of one-third of lime:
whereas that of Esperon,. treated in the same manner, did
not exhibit the smallest sign of fusion.
  The specific gravity of white feld spar is  25,9 '.5.—
See Brisson.
  Feld spar exhibits several varieties in its form  and  co-
lour..
  Most of the pieces of feld spar inclosed in granite have
a rhomboidal form; and when this  primitive rock  be-
comes decomposed, the crystals of  feld spar are detached,
and remain confounded with the rubbish.  The  granites
of our province,  almost all of them, contain these  cry-
stals, some of which are an inch and a half in diameter.
  Feld  spar has been  found crystallized in tetrahedral
prisms,  terminating in pyramids with four sides.
  I possess some specimens  of feld spar of Auvergne,
whose tetrahedral prisms are flattened and terminated by
a dihedral summit.      ,
  The principal shades of colour in feld  spar are white,
rose-colour,  and chatoyant, or of changeable colours.
   The white transparent feld spar is very rare ;  there is
a piece in the Royal Cabinet of the mineral School, which
comes from Mount St.  Gothar.
   One hundred parts of white feld spar contain about
sixty-seven silex,  fourteen alumine, eleven  barytes,  and
eight magnesia.
  The rose-coloured feld spar is not very  scarce.   Our
mountains exhibit much  of  It.   It  abounds with  iron,
which is in the state of  ochre.   Some experiments  have
shewn me that this variety is more fusible than the others.
My analyses have even exhibited a larger portion of mag-
nesia ; and its consistence appears to me  to be  less  firm
than that of other specimens.
  Feld spar is composed of rhomboidal lamins, which
give it the property of exhibiting  various  colours,   in a 
             EARTHY MIXTURES.   STONES.        307

•greater  or less degree.   Large pieces of feld spar have
been found on the  northern coast  of  Labrador,  worn
down by the waters into a round form,  of a  blueish grey
■colour, and exhibiting the most agreeable change of co-
lours,  according to the variation  of position.   The co-
lours are  a beautiful  celestial blue, shaded with green.
This stone is  known by  the name of Labrador Stone.
Granites are .frequently found, in which the feld spar ex-
hibits its changeable colours without being wrought*


                       CLASS ILL

Concerning the Mixtures of Stones among each other.
               Stony Mixtures.   Rocks.

   The mixture of the primitive earths with each other
form the stones we have hitherto  treated of;  and these
stones,  united and connected together, or as  it  were join-
ed by  a  cement,  constitute the numerous class  of peb-
bles or stones, concerning  which we shall proceed to
treat.   It is evidently seen  that the  mixture  of various
stones has been  produced, -either  by  revolutions which
have reversed and confounded the whole surface of coun-
tries, or by the action of waters, which have  successively
formed the strata of rounded flints spread over the sur-
face of the globe, and have afterwards deposited in their
interstices that earthy matter  wliich has  connected them
together.   These mixtures  have afterwards acquired  a
degree of  hardness;  and at length appeared to  form one
single substance.
   We shall establish our  genera upon the  presence  of
such stones as predominate-;  and the species  will be de-
duced from the variety of stones mixed with that which
determines the -genus.

  * Beautiful red, white, and green feld spar is found accompa
nying quartz in this country.
  A  great many varieties of quartz are found in the  United States.
It composes part  of the granites of New-York, and  is  found of a
white and red colour..  There is  a variety of a dark  blue colour,
found near West-Chester, Pennsylvania,—Am. Ed. 
30$         EARTHY MIXTURES.  STONll
                      GENUS I.

Rocks formed by the Mixture of Calcareous Stones with
                    other Species.

  Though the basis of calcareous stones  enters into  the
composition of the greater part of lithologic substances,
we find few rocks which can be ranged in this  class.


                     SPECIES I.

     Carbonate of Lime,  and Sulphate of Barytes.

  Mr. Kirwan observed compound stones in Derbyshire,
formed of chalk intermixed with nodules of  ponderous
spar.
                     SPECIES II.

             Carbonate of Lime and Mica.

  The green marble or Cipolin of Autun is of this kind.
It is composed of eighty-three parts carbonate of lime,
twelve green mica,  and one iron.—Journal de  Physique,
t. xii. page  55.  Calcareous stones  are  found in Italy,
which exhibit brilliant specks of mica, and are known by
the  name of Masigno.


                    SPECIES III.

    Mixtures of Calcareous and Magnesian Stones.

  Sulphate of lime, fluate of lime, and carbonate of lime,
are  found mixed  with  steatites, serpentine, talk,  amian-
thus, and asbestos.   Such is, for example, the white mar-
ble  interspersed with spots of steatites, and described by
Cronstadt. 
KARTHY MIXTURES.   STONES.
309
                     SPECIES IV.

     Calcareous Stones, and Fragments of Quartz.

  Quartz is sometimes found in calcareous cement. Swe-
den and Siberia exhibit several marbles  which give fire
with the  steel.  The calcareous grit,  so  common in the
southern part of our kingdom,  is of this  species.  The
sand is composed of fi*agments of quartzose flints, round-
ed and connected by a calcareous gluten or cement.   By
digestion of grit-stone in an acid, the calcareous cement
becomes dissolved, and the proportion which the sand
bears to  the whole may then be easily determined.
  This grit-stone is seldom hard enough to  be  used  in
building, or in paving.
  At Nemours, and at Fontainbleau, this stone has been
found crystallized in perfect rhomboides:  the cabinets of
naturalists are enriched with superb samples of this kind.
  Lime-stone has likewise been  found serving  as a  ce-
ment for feld spar,  schorl, &c.; but this is  somewhat
rare.
  Mr. De Saussure has described a stone whose elements
are quartz and spar.
  Our shores afford pebbles of  hard marble  of a light-
grey colour, interspersed with feld spaitand quartz.—See
Dorthes.


                      GENUS  II.

 Compound  Stones formed by the Mixture  of Barytic
               Stones with other Stones.

   As ponderous spar is  of considerable scarcity, and  is
almost  always found alone, this genus will not be nume-
rous. 
310
EARTHY  MIXTURES.   STONES.
                      SPECIES I.

Ponderous Spar mixed with a small quantity of Calca-
                     reous Spar.

   The diocesses of Alais and of  Uzes afforded me this
species;  and I have myself observed in the latter  rhom-
boids of  calcareous spar, so well mixed with the laminae
of ponderous  spar, that it is impossible to separate them
without destroying the stone.   It was among the veins of
ponderous spar which are found on the road from Portes
to Alais,  that I saw this mixture.


                     SPECIES II.

           Ponderous Spar and Serpentine.

   Mr. Kirwan describes a species  of serpentine with
spots of barytes.


                     SPECIES III.

           Ponderous Spar and Fluor Spar.

   The ponderous  spar of Auvergne is  mixed with flubr
spar: I have many specimens of  this.

                     SPECIES IV.

         Ponderous Spar and Indurated  Clay.

   This is the Kros-stein  of the Germans.   The clay
which forms the ground is grey, and includes a ponderous
spar of a white colour,  which is disposed in this clay  in
the form of veins, that might be taken at first  sight for
vermiculites, or in general, for the remains of some or-
ganized substances.   This stone is found  at Bochnia  in
Poland. 
EARTHY  MIXTURES.  STONES.        311
                     SPECIES- V.

            Ponderous Spar  and Quartz.

  I have in my collection several specimens, in which the
ponderous spar is disposed in stars upon a matrix of the
nature of silex.


                    SPECIES VI.

              Ponderous Spar and Lava.

  The extinct volcanos of the  diocess of Beziers have af-
forded me lavas, partly decomposed, whose surface exhi-
bits radii of ponderous  spar, which, at first sight I took to
be zeolite.       r


                      GENUS III.

 Rocks or Stones formed by the Mixture of Magnesian
               Stoneswith other Kinds,


                      SPECIES I.

          Magnesian  Stones mixed together.

  The same rock often exhibits the various known mag-
nesian stones in contact with  each  other.   Thus we see
the asbestos  placed beside the amianthus,  the serpentine
in contact  with the asbestos, the steatites in contact with
talk.                   i


                     SPECIES II.

       Magnesian Stones and Calcareous Stones.

  The serpentine has been found spotted with calcareous
spar, and gypsum. 
312
EARTHY MIXTURES.   STONES.
                     SPECIES III.

       Magnesian Stones and Aluminous Stones.

  Steatites is  frequently mixed with clay.  Its fibres are
found bedded in an argillaceous substance.  Steatites and
serpentine are sometimes mixed with schistus.


                    SPECIES IV.

        Magnesian Stones and Siliceous Stones.

  Serpentine is found  mixed with veins of quartz, feld
spar, schorl, he.
  Asbestos  and  amianthus  are often confounded,  and
sometimes incorporated  in quartz and rock-crystal.
  Mr. De Saussure  has described a compound stone, of
which the quartz is white, and the  steatites green.
  At Sterzing in Tryol, is found a rock formed by schorl
and serpentine.
  In the county of Mansfield in Saxony,  a rock has been
discovered, composed of jasper and asbestos.


                     GENUS IV.

  Rocks or Stones formed by the Mixture of Aluminous
              Stones with other Species.


                      SPECIES I.

                  Schistus ana1 Mica.

  This mixture forms several primitive mountains.  The
mica is sometimes in plates  of a  certain thickness, but
most commonly in small fragments; and the stone assumes
a brilliant argentine appearance, which renders these stones
agreeable to die sight.   In this  last case, the  stone is
nearly white, sonorous, and splits into leaves; whereas it is 
EARTHY MIXTURES.
STONES.
313
"blackish, and less hard, wjien the mica is dispersed through
it in large grains.
   These kinds of micaceous schisti do not become spon-
taneously decomposed.   They differ essentially from the
pyritous schistus, wjiose formation appears to be posterior
to that of the present species.                  ♦
   This micaceous schistus is a primitive stone.  It  does
not include minerals, or at least very rarely^ and it is not
spontaneously decomposed.


                      SPECIES II.

                  Schistus and Garnet

   The schistus freqiiendy contains garnets, which rise in
protuberances in its texture, and separate its strata from
each other.  The garnet is crystallized, and  one would
be disposed to affirm that this stone had increased, and al-
most vegetated, in the other, which serves as its covering.
It is probable that the garnet has been enveloped by this
paste of schistuss or that  it was formed while the  stone
was still almost in the fluid state.
   I found this schistus filled with garnets in the bed of the  -
*iver Bramabiou, in the diocese of Alais.


                     SPECIES III.

 Schistus, Mica, and Quartz, mixed in small Fragments,

   The Germans call this compound stone by the name of
Gneiss.  It deserves to be included among the quartzose
and siliceous stones; but  as it nearly approaches the pri-
mitive schisti we have just treated of, we shall follow the
natural method in classing it here.
   The texture of this stone varies  greatly.  It sometimes
 forms a rock in which neither ground nor fibres can be dis-
tinguished; in other specimens it  appears to be divided
 into filaments twisted in a thousand manners,  and it fre-
 quentiy exhibits a lamellated hard texture.
   It is found in large masses of a  greyish-green colour,
 with its surface shiSng, and polished like the slate; and
                            Kr 
314         EARTHY MIXTURES.   STONES.
it appears to be merely a fine-grained granite, the minute-
ness of whose parts has suffered them to take the foliated
form of the schistus.
  Mr. Weigleb has analyzed that of Friburg.


                     SPECIES IV.

                 Schistus and Schorl.

  The mixture  of  these two stones is  common enough.
The schorl is  sometimes dispersed  in  very minute fila-
ments, which  give a blackish tinge to the mass.  Its form
is often prismatic;  in which case the fibres  of the schis-
tus, and the long crystals of the schorl form the prism by
their reunion.
  A schistus has been found in the Pyrenean mountains,
in which the  schorl is spread  from space to space in the
form of oblong bodies, and equally dispersed over the
whole mass.


                     SPECIES V.

                  Clay and Quartz.

  This constitutes the argillaceous grit-stone, or the stone
in which fragments of quartz are  united together by an ar-
gillaceous gluten.
  Several varieties of grit-stone may be distinguished.  It
is often found in irregular,  coarse,  and compact masses,
which are made into mill-stones, or used for paving, &c.
  The magnitude of the fragments of quartz renders the
surface more or less rugged;   and it is this which renders
it proper for certain operations of trituration.
  When its grain is finer, it is made into grind-stones. It
is by virtue of their quartzous principles that grindstones
emit such numerous sparks,  when  struck with the steel,
or when they  are moved with rapidity against any tool of
that  metal.
  Argillaceous grit-stone is sometimes of a scaly texture:
the Cos Turcica of Wallerius, and the stone used for shar-
pening scythes, are of this kind, 
            fcARTHY MIXTURES.   STONES.         315

  Fine grit-stone,  composed of impalpable particles, is
known by the name of Tripoli, from the part of Africa
whence it  first came.   It is now found in  Rouergue, in
Britanny, Germany, and elsewhere.
  The porous grit-stone called Filtering-stone, on account
of its use, is of the same nature.
  Quartz is sometimes mixed with  mica.   Our province
contains it in various places.
  The mica is likewise  found mixed,
  1. With feld spar, according to Ferber and Kirwan.
  2. With schorl, at Mont hykie in Dalecarlia, in Sweden,
and at Sterzing in Tyrol.
  3. With garnets, at Paternion in  Carinthia,  and at the
Carpathian mountains in Hungary.
  4. With garnet and schorl, at Greyner.—See Muller.
  5. With quartz, feld  spar, and schorl.  This composi-
tion forms one of the most common granites.
  The mixture of these stones, varied in the  proportion
of their principles or elements, forms the  numerous va-
riety of granites:  and several colours likewise modify them
exceedingly.


                     GENUS V.

Compound Stones formed by the Mixture and Re-union
         of Quartzose  Stones with each other.


                      SPECIES I.

                  Quartz and Schorl.

  The quartz is, in general, white in this stone,  and the
schorl of various colours.   Some of the paving-stones of
London are of this sort, according to Kirwan. The schorl
is likewise found in crystals within the quartz. 
316
EARTHY MIXTURES.
STONES*
                     SPECIES II.

                Quartz and Feld Spar.

  A stone of this nature was brought me from the neigh-
bourhood of Avenes.  The mpuntain from whish the spe -
cimen was detached, contains about one third of quartz.
The rest of the rock consists of rhomboidal feld spar,  of
no great firmness of texture, and constantly exhibiting the
rhombus in its fracture.
  I possess a very fine specimen of a similar rock, which
was sent me from Fahlun in Dalecarlia.


                     SPECIES III.

                Grit-stone and Garnet.

  I have received from the mines of Tallard, near Gap in
Dauphiny, grit-stones with garnets of  one or two lines in
diameter interspersed.  These garnets are dispersed through
the whole mass, at the distance of three or four lines from
each other.,


                     SPECIES  IV.

           Quartz, Feld  Spar, and Schorl.

  This  mixture is common, and forms great part of the
granites on our globe.
  The proportion of the elements of this rock vary great-
ly, but the forms of the  stones which  compose it are not
less variable.  The schorl is  frequently crystallized  in
prisms;  the feld spar almost always exhibits rhomboidal
laminae, on breaking the stone;  the quartz very seldom
exhibits determinate figures, but it has nevertheless been
found in superb crystals at Alenr/on and elsewhere.
  The colour of these stones, likewise, exhibits an infinity
of shades.  The schorli is usually black; but it is some-
times found green, and even white, as in  some granites 
            EARTHY MIXTURES.   STONES.        517

brought from Spain.   The feld spar is  commonly of an
ash grey;  but it has been observed of a flesh-colour, of a
milk-white, of a dull red,  &c.  The most common ap-
pearance of  the quartz is, that of  a fat  and vitreous sub-
stance.  It is sometimes black.


                     SPECIES V.

 Fragments of Quartz united by a Siliceous Cement.

  We may here class the quartzose plum-pudding stones.
The cement which unites these pebbles of quartz, which
are commonly rounded, is the paste of petro-silex. Some
of these pudding-stones are so  compact, and their fracture
is so uniform, that they are capable of the most beautiful
polish, and produce a very happy effect by the variety of
colour of the several flints connected by the same gluten.


                     SPECIES VI.

               Jasper and Feld Spar,

  This rock is known by the name of Porphyry.  The
jasper composes the ground, and the feld spar  is inter-
spersed in small needles, or in flat parallelopipedons.
  The colour of porphyry varies prodigiously.  The feld
spar, which  enters into its composition,  is either white, or
yellowish, or red; but the name of the porphyry is always
dependant on the colour of the jasper.  The jasper is some-
times green and sometimes black, and  in some instances
red; which establishes a great number of varieties.
  As this stone is susceptible of the most beautiful polish,
it has been  employed as an ornament;  and our  temples,
as well as private houses, are decorated  with it.
  Mr. Ferber found in Tyrol  porphyry in prismatic co-
lumns, resembling that of basaltes; a circumstance which
affords a further degree of probability to the  opinion of
such as have considered porphyry to be a volcanic pro-
duction.
  Porphyry is found in Egypt, in Italy, in  Germany, in
Sweden, in France, &c.   Mr. Dorthes has brought, from 
 318         EARTHY MIXTURES.   STONES.

 various mountains in Auvergne, specimens of porphyric
 basaltes in tables and in masses, containing crystals of feld
 spar, well formed, and little altered.
   He observed that the  rocks of Chevenon, an ancient
 convent of Gramontin, at the distance of one league from
 Artonne in Auvergne, were very beautiful porphyry.  Mr.
 Guettard found it likewise in the forest of Esterelle in
 Provence.
   Mr. Dorthes has described  more than twenty varieties
 of porphyry thrown  up in pebbles by the Mediterranean
 upon our coasts, whither they are brought by the Rhone.
 In many of these  are found transparent quartz  with the
 prismatic form, and crystallized feld spar.
   Porphyry fuses into a black globule, marked with white
 points.
   The specific gravity of red porphyry is 27,651, and that
 of green, 26,760.—Brisson.
   Porphyry  sometimes contains schorl.  Wallerius has de-
 scribed it "Porphir rubens, cum spatho scintillante albo,
 et basalto nigro."


                     SPECIES VII.

                  Jasper and Garnet.

   This stone has  been discovered in Iceland; the ground
is  a green jasper,  which includes ferruginous garnets crys-
tallized, and of a red colour.


                    SPECIES VIII.

                Jasper and Calcedony.

   The Mountain of Giants, in Bohemia, affords this stone.
It  has likewise been found in the Carpathian mountains,
near Kaskau in Hungary.   A stone has likewise been ob-
served at Oberstein, in the Palatinate, composed of agate
and jasper. 
EARTHY MIXTURES.
STONES.
319
                     SPECIES IX.

                 Jasper and Quartz.

  This compound  stone, called  Saxum  Sibericum by
Linnaeus,  has been found in Siberia, and also near Stut-
gard in the Dutchy of Wirtemburg.
                     SPECIES X.

            Jasper,  Quartz, and Feld Spar.

   This stone is found in  the  environs of Geneva.  Its
ground is a jasper, or rather a petro-silex, black, opaque,
and very  hard.  This matrix is interspersed with small
rectangular crystals of white feld spar, and rounded grains
of transparent quartz.   Mr. De Saussure, who has de-
scribed this species, places it among the porphyries.


                     SPECIES XI.

           Schorl, Garnet, and Tourmaline.

   Mr. Muller has discovered  in Schneeburg, a mountain
of the territory of Sterzing in Tyrol, a rock of  this kind,
containing large crystals  of tourmaline,  which include
small crystallized garnets, transparent, and of a red colour.
   Mr. Ferber affirms that he found between Faistritz and
Carnowitz in Stiria, detached pieces of green  schorl,
which inclose large red garnets: he adds,  that this schorl
is sometimes scaly, and  of a micaceous texture.
   Mr. de Saussure has found in the environs of Geneva,
stones  worn  round by  water, which were composed of
schorl in the mass, and garnet.
  The Mediterranean Sea throws up on  our coast many
varieties of rounded pebbles of porphyry, which have schorl
for tiieir basis. 
320         EARTHY MIXTURES.  STONES.
                    GENUS VI.
Super-compound Stones, or such as result from the Mix-
    iure and Re-union of several different Genera.
                     SPECIES I.
      Petrosilex, Alumine, and Calcareous Spar.
  This stone is found at Schneeburg in Saxony.
                     SPECIES II.
         Clay,  Steatites, and Calcareous Spar.
  This  species, as well as the  two following, are com-
prised under the name of Saxa Glandulosa.  The steatites,
the spar, and the other substances  are  dispersed in the
matter which forms the ground of this rock.
                     SPECIES III.
      Clay, Zeolite,  Schorl, and Calcareous Spar,

                     SPECIES IV.
        Clay, Serpentine, and Calcareous Spar,

                     SPECIES V.
        Serpentine, Mica, and Calcareous Spar.
   Mr. Ferber  has described this  last  species under the
name of Polzevera; a denomination suggested to him by
the place where it is found.  See his Letters on Italy, 
EARTHY MIXTURES.   STONES.         3.21
                     SPECIES VI.

       Serpentine, Schorl, and Calcareous Stone.

   This stone surrounds the veins of the mine of St. Si-
 mon'and Jude, at Dognasta, in the Bannat of Temesward:
 it is likewise found in the copper mines of Saska; and at
 Hoferschlag, near Schemnitz, in Lower Hungary.

                    SPECIES VII.

             Steatites, Mica, and Garnets.

   This stone is found at  Handol in  Jempterland, towards
 the north of Sweden.r—Born. Ind. Foss. par. ii.

                    SPECIES VIII.

              Steatites, Mica, and Schorl.

  • This stone was found  at Salbury in Westmanland, a
 province of Sweden.—Born. Ind. Foss. par. ii.

                     SPECIES IX.

        Garnets, Quartz, Mica, and Serpentine.

   This contains a small quantity of  pyrites.   It is found
 at Pusterthal in Tyrol.—See Bruckman.

                     SPECIES X.
         Feld Spar, Quartz, Mica, Steatites.

   Several granites are formed by a mixture of this nature.
 Such are found at Sunneskog in Sweden, and at Guten
Hoffnangsban near Altwoschitz in Bohemia:  it is the^ra-
nites steatite mixtus of Born.

                     SPECIES XI.
               Quartz, Mica, and Clay.

  This rock is  the matrix of the ore of tin at Platte,  and
at Gottesgab in Bohemia.
                           Ss 
THE  DIAMONEi
                  SPECIES XII.

          Quartz,  Clay, and Steatites.

This is found at Mount St. Gothard in Switzerland".
               Concerning the Diamond.

   The Diamond forms an appendix to the history of
 stones.  Its combustibility is  a character which prevents
 its being assimilated to any known species.
   The diamond was long considered as the  hardest and
 most ponderous of  stones,  as  well as the only one which
 did not cause a double refraction;  but subsequent obser-
 vations have destroyed these early  notions.  The adaman-
 tine  spar appears to equal it in hardness;  the oriental ruby,
 and  the jargon of Ceylon, are  more ponderous;  and the
 oriental precious stones exhibit one  refraction only, as does
 likewise the phosphoric spar.
  This precious stone is found on  the coast of Coroman-
 del,  and principally in the kingdoms of Golconda and Vi-
 sapour.  The earth which serves  as  its gangue is red,
 ochreous, and soils  the  fingers.
  The general process  of exploring  the diamond mines
 or earths, consists in mixing the earth with water, after
 which the fluid is poured off, and the sand which remains
 at the bottom is dried by the strong heat of the sun.—See
 the memoirs of the Comte Marechal.
  Other naturalists  inform us that, when the earths have
 been washed;  the residue is left to dry,  and  is  sifted in
 baskets made for the purpose.   The workmen afterwards
 seek for the diamonds with their hands.
  Diamonds in their native state  are  covered with two
crusts; the one earthy, and the other  sparry.—Rome de
Lisle.
  When lapidaries undertake  to  work them,  they are
obliged to find the grain of the stone,  in order to split or 
THE DIAMOND.                323
•cleave the diamond.  If the fracture be not uniform, they
call the stone a diamond of nature.  The hardness of the
diamond is such,  that it resists the most highly polished
steel;  which circumstance renders it necessary to attack
it by diamond powder.
   The manner or  form in which diamonds are cut, dis-
tinguishes them into rose diamonds, and brilliants, or bril-
liant diamonds.   The brilliant diamond is cut into facets
on both sides.   The variety of forms given to these  fa-
cets, and their different inclinations with respect to each
other, multiply the refractions, and contribute  to afford
those  reflections,  and streams of pure  and vivid light,
which characterize the diamond.
   The diamond is divided into  two kinds;  the  oriental
diamond, and the Brazilian diamond.
    The oriental diamond  crystallizes in octahedrons, and
 exhibits all the varieties of this primitive form.
   The Brazilian diamond crystallizes in dodecahedrons,
 It is neither so hard, so heavy, so perfect, nor so valuable,
 as the oriental diamond.
    The colourless diamond has a specific gravity which is
 in proportion to that of water as  35,212 to 10,000.  Mr.
 Brisson has derived this specific  gravity from an  experi-
ment on the Pitt diamond of the French crown.  A cubic
 foot of this diamond would weigh two hundred and forty-
 six livres, seven ounces,  five gross, sixty-nine  grains.
    The diamond  is  sometimes  coloured green,  violet,
 black,  &c.  The green are the most esteemed, because
 they are the most scarce.  The weight  of coloured dia-
 monds is more considerable  than that  of the white dia-
 mond; because it is augmented by the weight of the  co-
 louring principle,  which is of a metallic nature.
    The brilliancy, hardness,  and scarcity of the diamond
 have preserved it  in the most extravagant degree  of esti-
 mation.  A diamond is said to be of a fine water  when it
 presents no defect or spot;  and  die price is proportioned
to its purity.
    When a diamond is without fault, its value is estimated
 according to its weight;  which is determined  or divided
 into  carats,  each  carat being equivalent to about four
igrains. 
324
THE DIAMOND.
   The most beautiful diamonds hitherto known  are—1.
The two in the crown of the King of France; one of which
is die Grand Sancy, weighing one hundred and six carats;
and the other the Pitt, which weighs seven gross, twenty-
five grains and one-sixteenth.  It is fourteen lines long,
thirteen and a  half broad,  and nine and one-third thick.
2. The diamond which at present belongs to the  Czarina
weighs seven hundred and seventy-nine carats.  The Em-
press purchased it in 1772 for twelve tons of gold (100,000
florins), and granted a pension of four thousand rubles to
the seller.   It is pretended that this fine diamond was one
of those which ornamented the eyes of the famous statue
Scheringham,  which has  eight eyes and  four heads; and
that it was carried off by a French deserter who had pro-
cured himself to be appointed as a guard to the temple of
Brama.   This diamond was at first  sold for fifty thou-
sand livres, afterwards for about four hundred thousand
livres,  and  was at length purchased by the Empress of
Russia.
   The combustibility  of  the  diamond is a phenomenon
sufficiently interesting to induce us to give a faithful ex-
tract of the principal experiments which have served to ad-
vance our knowledge upon this subject.
   Boyle observed, long since,  that the diamond, exposed
to a violent fire, emitted acrid vapours.
   The Emperor Francis the First caused crucibles to be
exposed to a reverberatory fire for twenty-four hours, into
wliich vessels the value of six thousand florins in diamonds
and rubies  were put.  The diamonds disappeared,  but
the rubies were not altered.  These experiments were re-
peated with great expense;  and  it was ascertained that
the diamond lost its polish, scaled off, and was dissipated.
   The Great Duke of Tuscany, in 1694, caused experi-
ments to  be made by Mr. Averoni and Targioni, by the
mirror of Tschirnausen, and it was found that the diamonds
disappeared in  a few minutes.
   In 1772,  these experiments were resumed by the skil-
ful chemists of Paris—Darcet, the Comte de Laraguais,
Cadet, Lavoisier, Mitouard, Macquer, &c.   The details
of the  interesting experiments made on this subject may
be seen  in the  volumes of the Academy of Sciences, and
the Journaux de Physique of that year.  We shall simply
relate the results. 
THE DIAMOND.
325
   1. Messrs. Darcet and the Comte de Laraguais proved
that the diamond is volatilized in balls of porcelain.
   2. Mr. Macquer took notice that the diamond dilated
and swelled up;  and that a blue flame was observable on
its surface during the combustion.
   3. Messrs. Lavoisier and Cadet proved, that the combus-
tion of diamonds in closed vessels ceased as soon as the
oxigene was destroyed; and  that the diamond did not burn
but in proportion  to  the oxigene present, like  all other
combustible substances.  The jewellers, who expose their
diamonds to very violent fires to render them colourless,
are careful to wrap them up in such a manner as to secure
them from the contact of air.
   Mr. De Saussure burned a diamond by the blow-pipe:
Mr. Lavoisier has proved that, when it is exposed to the
burning glass, a dust arises which precipitates lime-water.
   The diamond is therefore a combustible substance, which
burns in the same manner as other  bodies.   This strict
 and accurate consequence is deduced from all the experi-
 ments which can be imagined to acquire a perfect demon-
 stration.
    Within  a few years chemists  have  discovered a very
 singular stone, to which the name of Adamantine Spar has
 been given by Bergmann.
    It is black, and so hard that its powder may be used to
 cut the diamond;  from which circumstance it has obtained
 its name.
    It crystallizes in hexahedral or six-sided prisms, two
 of which are large and four small.
    Its specific gravity is 38,732  with respect  to water,
 which is assumed at 10,000.   See Brisson.—The cubic
 foot  weighs two  hundred and seventy-one livres, one
 ounce,  seven gross,  sixty three grains.
    The  most violent fire produces only a  slight  softening
 of this  spar,  according to the experiments of Mr. Lavoi-
 sier.
    The  analysis made by Mr. Klaproth of this stone, has
 exhibited  a peculiar earth, which is suspected to be like-
 wise one of the principles of precious stones, &c. 
326
G.EOLOGICAL OBSERVATIONS.
             GENERAL  VIEWS

                    RESPECTING

The Decompositions and Changes to which  the Stony
         Part of our Globe has been subjected.


   IF it were permitted to man to  follow,  during several
    ages,  the various changes which are produced on the
surface of our globe by the numerous agents that alter it,
we should at this time have been in possession of the most
valuable information respecting  these great phenomena :
but thrown, as we are, almost by accident, upon a small
point of this vast theatre of observation, we fix  our  at-
tention for a  moment upon operations which have em-
ployed the works of Rature for ages;  and we  are unable
either to perceive or to foretel the results,  because  seve-
ral ages  are  scarcely sufficient to render the effects or
changes perceptible.  Nature never ceases to exist: her
activity has  been  coeval with the existence  of matter;
her operations are not circumscribed within limited times;
she disposes of whole ages  in the arrangement of her
combinations; while man can command no more than  a
few instants, and himself disappears at the moment wherein
he has proceeded so far as to  connect a few facts together.
Hence, no doubt,  it arises, that nature is incomprehensi-
ble in some of her operations, and inimitable in all  those
which require a long series of time.
   It must be allowed that those men  who,  by the  mere
efforts  of their imagination,  have endeavoured to form
ideas respecting the consunction, and the great pheno-
mena of  this globe, have numerous  titles to our indul-
gence.  In their proceedings  we behold the efforts of ge-
nius, tormented with the desire of acquiring  knowledge,
and irritated at the prospect of the scanty  means which
nature has put in its power:  and when these naturalists,
such as Mr. De Buffon. have  possessed the power of em- 
GEOLOGICAL  OFSERVATIONS.
327
bellishing their  hypotheses with every ornament which
imagination and eloquence can furnish, either  as instru-
ments of illusion or entertainment, we ought to  consider
ourselves indebted to them.
   For our part,  we shall  confine  ourselves to exhibit a
few ideas respecting the successive decompositions of our
planet, and shall endeavour to avoid every departure  from
observation and matter of fact.
   The slightest observation  shews us that living beings
are kept up and perpetuated only by successive decom-
positions and combinations..   A slight view of the mine-
ral kingdom exhibits the same changes; and our globe,
in all its productions, presents continual modifications,
and a circle of activity, which might appear incompatible
with the apparent inertia of lithologic products.
   In order to arrange our ideas with greater  regularity 7
we may consider this globe in two different states.  We
will first examine the primitive rock which forms the no-
dule  or central part.   This appears to contain no germ of
life,  includes no remains  or part of any living being, and
from every circumstance  appears to have been of primi-
tive formation, anterior to the creation of animated or ve-
getating bodies.  We  shall  pursue the various  changes
which are daily produced by the destructive action of such
agents as alter or modify  this substance.
   We shall then proceed to  examine what  stones  have
been successively placed  upon this,  and what are the de-
compositions to which these  secondary rocks  have  been
subjected.
   1.  The observations of naturalists all unite to prove,
that the central part  of the  globe consists of the  stone
known by the name of Granite.   The profound excava-
tions which the art of man, or currents of water,  have
made in the surface of our planet, have all uncovered this
rock, and have been incapable of penetrating lower:  we
may  therefore consider this substance  as the nucleus of
the globe; and upon this substance it is that all  matters
of posterior formation rest
   Granite exhibits many varieties in  its  form, composi-
tion,  and disposition;  but it in general consists of an as-
semblage of certain siliceous stones, such as quartz, schorl,
feld  spar,  mica, &c.; and die more or less considerable 
328
GEOLOGICAL  OBSERVATIONS.
 magnitude of these elements of granite, has caused it to
 be divided into  coarse-grained granite,  and fine-grained
 granite.
   It appears to me that there is no denying but that these
 rocks owe their  arrangement to water :  and if we may be
 permitted to recur,  by an effort of die  imagination*, to
 that  epocha  in  which,  according to sacred and profane
 historians, the water and earth were confounded, and the
 confused  mixture of all principles formed a  chaos,  we
 shall see that the laws of gravity inherent in matter  must
 have carried  it down, and necessarily  produced the  ar-
 rangement which observation at present exhibits to  us.
 The wrater, as the least heavy, must have  purified itself,
 and arisen to the surface by a filtration through  the other
 materials : while the earthy principles must have precipi-
 tated, and formed a mud,  in which  all the elements of
 stones were confounded.   In  this very  natural order of
 things, the general law  of affinities, which  continually
 tends to bring together all analogous parts, must have  ex-
 erted itself with its whole activity upon the principles of
 this almost fluid  paste ; and the result must have been a
 number of bodies  of a  more definite  kind,  in crystals
 more or less  regular: and  from  this muddy substance,
 in which  the  principles of the stones  were confounded
 that compose the granite, a rock  must have been pro-
 duced, containing the elementary stones all in possession
 of their distinct forms and characters.   In this manner it
 is that we observe salts of very  different  kinds develop
 themselves in waters which hold  them  in solution;  and
 in this manner it still happens that crystals of spar  and
 gypsum are formed in clays which contain their compo-
 nent parts.
  It may easily be conceived that the laws of gravitation
 must have influenced the arrangement and disposition of
 the products!   The most gross and  heavy bodies  must
have  fallen, and  the lightest  and most attenuated  sub-

  * This is the first and the last supposition in which I shall indulge
myself.  It is a conjecture, however, which is indifferent with re-
spect to the basis of  the subject itself; since it relates only to an hy-
pothesis respecting the  manner  in which a  rock might be formed
that at present exists, and whose decompositions alone  can form
the subject tsf- our  observations. 
GEOLOGICAL  OBSERVATIONS.
329
stances must have arranged themselves on the  surface of
the foregoing : and this it is which constitutes the primi-
tive schisti, the  gneis,  the  rocks of  mica, &c. which
commonly repose upon masses of coarse-grained granite.
   The disposition of the fine-grained granite in strata or
beds,  appears to me to depend on this  position,  and the
fineness or tenuity of its parts.   Being placed  in imme-
diate contact with water,  this fluid must naturally  have
influenced the arrangement which it presents to  us ; and
the elements of this rock being subjected tothe  effect of
waves, and the  action  of currents, must have formed
strata.
   The rocks of  granite being once established as the nu-
cleus of our globe,  we may, from the analysis  of its con-
stituent principles, and by attending to the  action of the
various agents capable of altering it,  follow the  degrada-
tions to which it has been subjected, step by step.
   Water is the principal agent whose effects we  shall ex-
amine.
   This fluid,  collected in the cavity of the ocean, is car-
ried by the winds to the tops of the most elevated moun-
tains,  where it is precipitated in rain,  and forms torrents,
which return with  various  degrees of rapidity  into the
common reservoir.
   This uninterrupted motion and fall must gradually at-
tenuate and wear away the hardest rocks, and  cany their
pulverulent parts to distances more or less considerable.
The action of the air, and  varying  temperatures of the
atmosphere, facilitate the attenuation and the  destruction
of these rocks.   Heat dries their surface,  and renders it
more  accessible and more penetrable to the  water which
succeeds;  cold divides them, by freezing the water which
has entered into their texture;  the air itself  affords the
 carbonic acid, which attacks the lime-stone, and causes
 it to effloresce ;  the oxigene unites to the iron,  and cal-
 cines  it:  insomuch that this concurrence of causes .fa-
 vours the disunion of principles; and consequentiy the
 action of water, which  clears  the surface, carries away
 the products of  decomposition, and makes preparation for
 a succeeding process of the same nature.
    The first effect of the rain is therefore to depress the
 mountains.   But the stones which compos*  them must
                            Tt 
3*30
GEOLOGICAL OBSERVATIONS.
resist in proportion to their hardness;  and we ought not
to be suq^rised when we observe peaks which have braved
the destructive action of time, and still remain to attest
the primitive level of the  mountains which  have disap-
peared.  The primitive rocks, alike inaccessible to the
injury of ages as to the animated beings which cover less
elevated mountains with their remains, may be considered
as the source or origin of  rivers and streams.  The  wa-
ter which falls on their  summits,  flows down in  torrents
by their lateral surfaces.  In its course it wears away the
soil upon which it incessantly acts.   It hollows out a bed,
of  a depth proportioned to the rapidity of its course, the
quantity of its waters, and the hardness of the rock over
which it flows ;  at the same time that it carries along with
it portions  and fragments of such stones  as  it loosens  in
its course.
   These stones,  rolled along by the water, must strike
together, and break off  their projecting angles : a process
that must quickly have afforded those rounded flints which
form the pebbles of  rivers. These pebbles are found  to
curnmish in size, in proportion  to the distance from the
mountain which affords them; and it is to this cause that
Mr. Dorthes has referred the disproportionate magnitude
of the pebbles which form our ancient worn stones, when
compared with those of modern date : for the sea extend-
ing itself formerly much more inland, in the direction  of
the Rhone, the stones which it received from the  rivers,
and threw  back again upon the shores, had not run through
so long a space in their beds as those which they at pre-
sent pass over.  Thus it is that the remains of the  Alps,,
carried along  by the Rhone,  have successively  covered
the vast interval comprised between the mountains  of
Dauphiny and  Vivarais;  and are carried into our seas,
which deposite them in small pebbles on the  shore.
   The pulverulent remains of mountains, or the powder
which results from the rounding of these' flints, are car-
ried along with greater facility than the flints  themselves :
they float for a long time in the water, whose transparence
they impair;  and when these same  waters  are less agi-
tated,  and their course, becomes  slackened, they  are de-
posited in a fine and light  paste,  forming beds  more  or
fess thick,  and of the same nature as that of die rocks to 
             GEOLOGICAL OBSERVATIONS.         331

"which they owe their origin.   These strata gradually he-
come drier by the agglutination of their principles ; they
become consistent, acquire hardness,  and form  siliceous
clays, silex, petrosilex, and all the numerous class of peb-
bles which are found dispersed in strata, or in banks,  in
the ancient beds of rivers.
   Mr.  Pallas has  observed the transition  of clay  to the
state of silex in the brook of Sunghir, near  Wolodimir.
Mr. J.  W. Baumer  has likewise  observed it in  Upper
Hesse.
   The "mud is much more frequently deposited in the in-
terstices left between the rounded flints themselves, which
intervals it fills, and there forms a true  cement  that be-
comes hard, and constitutes the compound stones known
by the name of pudding-stones and grit-stones; for these
two kinds of stone do not appear to me to differ but in
the coarseness of the  grain which forms them, and the ce-
ment which connects diem together.
   We sometimes observe the granite spontaneously de-
composed.   The  texture of the stones which form it has
been destroyed;  the principles or component parts are
disunited and separated, and they are gradually carried
away by the waters.  I  have  observed near  Mende, to-
wards Castlenouvel, the  most beautiful kaolin on the sur-
face of  a granite, in a state  of decomposition; and  this
same rock  is decomposed in  several other parts of our
province.   It appeared to me that the feld  spar wras parti-
cularly  subject to be altered the first.
   Most siliceous stones,  formed by the deposition of flu-
viatile waters, and hardened by the lapse of time, are easily
subjected to a second decomposition.  Iron is the princi-
pal agent of these  secondary  alterations; and its calcina-
tion, determined by air or water, produces a  disunion of
principles.   Nature may be observed  in this process, by
an attentive examination of such alterations as gun flints*
variolites, porphyries, jaspers, and die like, are subjected
to.
   The  decomposition of flints, calcedonies, agates, and ge-
nerally all  stones of this kind which possess a certain de-
gree of transparence, appears to me to be referable to the
volatilization of the water, which forms one of their prin-
ciples, and is the cause of their transparency. 
332
GEOLOGICAL OBSERVATIONS.
   These stones may be considered as commencements of
crystallization; and, when the water  is dissipated, they ef-
floresce after the manner of certain neutral salts.  Hence it
arises that the decomposition is announced by opacity, a
white colour, loss of consistence and hardness; and termi-
nates by forming a very attenuated powder, sometimes of
extreme whiteness.  It is this decomposition, more parti-
cularly, which forms clays.
   There  are flints whose alterations form effervescent
marls.  These do not appear to me to be of the nature
of primitive rocks: they have the same origin as the calca-
reous stones,  from which they differ only in  consequence
of a very  considerable proportion of clay.  The stones
which we  so abundantly  find of this nature around us,
among calcareous decompositions, may be considered as
of this kind.
   Water filtrating through mountains of primitive rock,
frequently carries along with it very  minutely divided par-
ticles of quartz;  and proceeds to form, by deposition, sta-
lactites, agates, rock crystal, he.
   These quartzose stalactites differently coloured, are of a
formation considerably analogous to  that of calcareous ala-
basters ; and we perceive no other difference between diem
than that of their constituent parts.
   II.  Thus far we have exhibited,  in a  few words, the
principal changes, and various modifications, to which the
primitive rocks  have  been subjected.  We have not yet
observed either germination  or  life;  and the metals, sul-
phur, and bitumens, have not hitherto presented themselves
to our observation.  Their formation appears to be poste-
rior to the existence of this primitive globe;  and the alte-
rations and decompositions  which now remain to be in-
quired into, appear to be produced by the class of living
or organized  beings.
   On the one hand, we behold the numerous class of shell
animals, which cause the stony mass of our  globe  to in-
crease by their remains.  The spoils  of these creatures,
long agitated and driven about by the  waves, and more or
less altered by collision, form those strata  and banks of
limestone, in which we very  often perceive impressions ot
those shells to which they owe their origin.
   On the other hand, we  observe a numerous quantity of
vegetables that grow  and perish in  the sea; and these 
GEOLOGICAL  OBSERVATIONS.
333
plants likewise, deposited and heaped together by the cur-
rents, form strata,  which are decomposed, lose their orga-
nization, and leave all the principles of the vegetable con-
founded with the earthy principle.   It  is  to  this source
that the origin of pit-coal, and secondary schistus, is usually
attributed; and this theory is established on the existence
of the texture of decomposed vegetables very usually seen
in schisti and coal, and likewise on the presence of shells
and fish in most of these products.
   It appears to me that the formation of pyrites ought to
be attributed to the decomposition of vegetables: it exists
in greater or less abundance in all schisti and coal. I have
found a wooden shovel  buried in the depositions of the ri-
ver De Ceze, converted into jet and pyrites.  The decom-
position of animal substances may be added to this cause:
and it appears to me  to be a confirmation of these ideas,
that we find many shells passed to the state of pyrites.
   Not only the marine  vegetables form considerable strata
by their decomposition; but the remains of  those which
grow on the surface  of the globe, ought to be considered
among the causes or  agents which concur in producing
changes upon that surface.
   We shall separately  consider how much  is owing to
each of these causes; and shall follow the effects of each,
as if that cause alone were employed in modifying and al-
tering our'planet.
   1.  The calcareous  mountains are constantly placed upon
the surface of the primitive  mountains;  and though a few
solitary observations  present a contrary order, we  ought
to consider this inversion and derangement as produced by
shocks which have changed the primitive disposition.  I
must observe also that the disorder is  sometimes merely
apparent;  and that some naturalists of little information
have described calcareous mountains as inclining beneath
the granite, because  this last pierces, as it were,  through
the envelope,  rises to  a greater height,  and leaves at its
feet, almost beneath  it, the calcareous remains deposited
at its base.
   Sometimes even the lime-stone fills to a very great depth
the crevices  or clefts formed in the granite.   I have seen
 in Gevaudan, towards  Florae, a profound cavity in the gra-
 nite filled with calcareous stone.   This vein is known to 
534
GEOLOGICAL OBSERVATIONS.
possess a depth of more than one hundred and fifty toises,
with a diameter of about two or three.
   It likewise happens frequently enough that such waters
as are loaded with the remains of the primitive granite,
heap them together,  and form secondary granites,  which
may exist above the  calcareous stone.
   These  calcareous  mountains are  decomposed by the
combined action of air and water; and the product of their
decomposition sometimes forms chalk or marl.
   The lightness of this earth renders it easy to be trans-
ported by water; and  this fluid,  which does not possess
the property of holding it in solution, soon deposites it in the
form of gurhs, alabasters, stalactites,  he.  Spars owe their
formation to no other cause.  Their  crystallization is pos-
terior to the origin of calcareous mountains.
   Waters wear down and cany away calcareous moun-
tains with greater ease thati the primitive mountains; their
remains being very light, are rolled along, and more or
less worn.  The fragments of these  rocks are sometimes
connected by a gluten or cement of the same nature; from
which process calcareous grit and breccias  arise.   These
calcareous remains formerly deposited themselves upon the
quartzose sand;  and the union  of  primitive matter, and
secondary products, gives rise to a rock of a mixed nature,
which is common in our province.
   2. The mountains of secondary schistus  frequently ex-
hibit to us a pure mixture of earthy principles, without
the smallest vestige of bitumen.  These rocks afford, by
analysis, silex, alumine, magnesia, lime in the state of car-
bonate, and iron;  principles which are more or less united,
and consequently accessible in various degrees to the action
of such agents as destroy the rocks hitherto treated of.
   These same principles when disunited, and carried away
by waters, give rise to a great part of the stones which we
have comprised in the  magnesian genus.   The same ele-
ments, worn down  by the waters,  and deposited under
circumstances proper to facilitate crystallization, form the
schorls, tourmaline, garnets, he.
   We do not pretend  by this to exclude and absolutely
reject the system of such naturalists as attribute die forma-
tion of magnesian stones to the decomposition of the pri-
mitive rocks.  But we think that this formation cannot 
CE0L0CICAL  OBSERVATIONS.         335
be objected to for several of them,  more especially such
as contain magnesia in the greatest abundance.
   It frequently happens that the secondary schisti are  in-
terspersed with pyrites;  and, in this case, the simple con-
tact of air and water facilitates their decomposition.  Sul-
phuric acid  is thus formed, which combines with the  va-
rious constituent principles of the  stone;  whence result
the sulphates of iron* of magnesia,, of alumine, and of lime,
which effloresce at the surface, and remain confounded to-
gether.   Schisti of this nature are wrought in most places
where alum  works have been established; and  the most
laborious part of this undertaking consists in separating
the sulphates of iron, of lime, and of magnesia from each
other, which are mixed together.  Sometimes the magne-
sia is so abundant that its suJphate predominates:  I have
seen mountains of schistus of this nature.  The sulphate
of lime being very sparingly soluble in water, is carried
away by  that liquid, and deposited to form gypsum; while
the other more soluble salts remaining suspended, form
vitriolic  mineral waters.
'   The pyritous schisti are frequently impregnated with bi-
tumen, and the proportions constitute the various qualities
of pit-coal.
   It  appears to me that we may lay it  down as an incon-
 testable  principle,  that the pyrites  is abundant in propor-
tion as the bituminous principle is  more scarce.  Hence
 it arises,  that coals of a bad quality are the most sulphure-
 ous, and destroy metallic vessels by converting them into
pyrites.   The focus of volcanos appears to be formed by
a schistus of this nature; and in the analyses of  the stony
matters which are ejected we find the same  principles as
those which constimte this schistus.   We ought not there-
 fore to be much surprised at finding schorls among volca-
nic products; and still less at observing that subterranean
fires throw sulphuric salts, sulphur,  and other analogous
 products out of the entrails or the earth.
   3. The remains of terrestrial vegetables exhibit a mix-
 ture of primitive earths more or less coloured by iron: we
 may therefore consider these as a matrix in which  the
 seeds of all stony combinations are dispersed.   The ear-
 thy principles  assort themselves according to the laws of
 their affinities; and form crystals of spar, of plaster,  and 
336
GEOLOGICAL OBSERVATIONS.
even the rock crystals, according to all appearance:  for we
find ochreous earths in which these  crystals are abund-
antly dispersed; we see  them formed almost under our
eyes.   I have frequently  observed  indurated ochres full of
these crystals terminating in two pyramids.
   The ochreous earths appear to me to deserve the greatest
attention of naturalists.   They constitute one of the most
Fertile means of action which nature employs; and it is even
in earths nearly similar to these that she elaborates die dia-
mond, in the kingdoms of Golconda and Visapour.   If it
were allowable to indulge in a fiction purely poetical,  wc
might affirm that the element of fire,  so far from being
lost by the dispersion of the combustible principles of  ve-
getables, becomes  purified to form this precious stone so
eminently combustible;  that nature has been desirous of
proving that the terms Destruction and Death are relative
only to the imperfection  of our senses; and that she is ne-
ver more fruitful than when we suppose her to  be at the
'moment of extinction.
   The spoils of animals which live on the  surface of the
globe, are  entitled  to some consideration among the num-
 rjer of  causes  which we  assign  to explain the various
 changes our planet is subjected to.  We find bones in a
 state of considerable preservation  in  certain places;   we
 can even frequentiy enough distinguish the  species of  the
 animals to which they have belonged.  From  indications
1 of this  sort it is  that some writers have endeavoured to
 explain the disappearance  of certain species; and to draw
 conclusions from thence, either that our planet  is percep-
 tibly cooled, or that a sensible change has taken place in
 the position of the axis of the earth. The phosphoric salts
 and phosphorus which have been  found, in our  time, in
 combination writh lead, iron, &c. prove that, in proportion
 as the principles are disengaged by animal decomposition,
 they combine  with other bodies, and form the  nitric acid,
 the alkalis,  and in general all die numerous kinds of ni-
 trous salts.
END OF THE FIRST VOLUME. 
INDEX.
A.
A
    CID, general properties
----Carbonic
----Sulphuric
■----Nitric
—— Muriatic
----Oxymuriatic
----Nitromuriatic
 ■    Boracic
— Fluoric
Affinity of aggregation
Affinity of composition
Agustina
Agate
Asbestos
Alkali "volatile
Alkalis
Alumine
Amianthus
Amethyst
Atmospheric air
Attraction

               B.

Balances
Barytes
Basaltes
Beryl
Blood, red color of
Borate of Potash
----- of Soda
 •*•  - of Ammoniac
c.
Page.

of 142
  I4i
  156
  166
  179
  18:
  197
  199
  235
   43
   45
  218
  288
  260
  138
  l3t
  215
  261
  286
  116
   42
  40
 21
 295
 279
 Hi
 202
ibid
 206
Calcedony
Carbone
Vol. I.
Cabonate of Potash
  —■----of Soda
  ------of Ammoniac
  ------of Lime
  ------of Barytes
  ------of Magnesia
  -.-----of Alumine
CIu mistry, method of study
 hrysolite
Chrysophrase
Carnelian
Crucibles
Crystallization

              D.

Decomposition, laws of
Diamond
Distilling vessels
Distillation of water

              E.

Elementary substances
Emerald
Evaporation
Evaporatory vessels

              F.
    Feld Spar
    i ire
    Flint
    Fluate of Lime
    Frigorific mixtures
290 Fulminating powder
 88 i urnaces
  U  u
 Page.
   152
   153
   1.54
   219
   241
   245
   249
ing 58
   279
   300
   291
    36
    50
 47
322
 24
134
 64
279
 76
 31
     305
       65
     287
     234
       75
     177
30 et seq. 
338
INDEX.
             G.

Garnet
Geological observations
Glucina
Gun-powder
Gypsum

             H.

Heat
Hornblende
Horn Stone
Hyacinth
Hydrogenous Gas

              I.
Inflammable air
J.
Jasper
             L.

Lapis Lazuli
Light
Lime
Lime water
Lithology
Liver of sulphur
Lutes

             M.

Magnesia
Marble
Mica
Mortar
Mountain Cork
Muriate of Potash
—.---  of Soda
------  of Ammoniac
------of Lime
------  of Barvtes
Page
276
328
217
176
230
Muriate of Magnesia

             N.

Nitrate of Potash
       of Soda
       of Ammoniac
       of Lime
       of Barytes
       of Magnesia
 66
269
270
278
 93
93
291
Nitrogene Gas
Nitrous Gas
Nitrous Oxide
             o.

Opal
Oxigenous Gas
  Use of in Phthisis
Oxide of Carbon
Oxymuriate of Potash
Page.
  244
172
178
178
237
242
244
114
169
179
289
 99
113
155
 187
	Plates, explanation of Phospateof Lime Potash		41 238 131
303 78	Pottery Porcelain		265 266
211			
228 207		Q.	
137 38	Quartz	R.	286
212 222 268 229 260	Retorts Reagents, effects of Rock Crystal Ruby Ruby false		34 57 282 276 284
190 191		S.	
195 238 242	Sapphire Serpentine		281, 285 259
 
INDEX.
339
                         Page.
Schorl                     293
Silex                       216
Solution                     54
Soda                       134
Strontites                  214
Steatites                   257
Slate                       270
Sublimation                 33
Sulphur                     84
Sulphate of Potash         16
~-------of  Soda          162
--------of  Ammoniac     164
--------of  Lime          230
--------of Barytes        239
         of  Magnesia      240
——— of  Alumine       246
Talk
Thermometers
Topaz
Tourmaline
rrapp
Page.
  299
V.
Vegetables exposed to light    80-

            w.

Water                    118
Water in the state of Gas.
  Composition of           126
Woulfe's Apparatus          38

             Y.

Yttria                     216
     256
      68
S77, 285
     292
Zeolite                    274
Zirconia                   317 
 
 
5Wr
Mv
%¥&■-; %
m
Vv ■*'.

■ I
*,  t
vt&
it
*£s
-*&
\
m.
■Vi
!L^&