'%:'f&&.
&m>
:V.5%3

'-?£&> • < -.:>.
S:
•l>
1  -J' t     :f' **. '■-;.  ■■'...: ■ '.>a
^p		:>*
l^£g!?	*-'•* "A	$'.'•
.^v	'•."*'■.*	5 -'■ -
 
y<
^
. , ^ckKw, «-^
^
SURGEON GENERAL'S OFFICE
    LIBBARY.
No


«tn 
r
( 
 
! J J/  />>'tr
ELEMENTS
OF
    CHEMISTR   F,

                     IN A

        NEW SYSTEMATIC ORDER,

              CONTAINING ALL THE

      MODERN  DISCOVERIES.

  ILLUSTRATED WITH THIRTEEN CfkrfERPLATES.

           BY Mr  LAVOISIER,

Member of the Academies and Societies of Pari*, London, Orleans,
  Bologna, Bafil, Philadelphia, Haerlem, Manchefler, &c. &c.
         TRANSLATED  FROM THE FRENCH,
     BY ROBERT KERR, F. R. Sc A. SS. Edin.
Member of the Royal College of Surgeons, and of the Royal Phyfical
                Society of Edinburgh.
      FOURTH  EDITION,
                  WITH
NOTF.S, TABLES, and CONSIDERJUSLE-^IirilTXQNS,
rfel.F ADDITIONS,
   LIJii.MR-y
PftllaDelptij:      JM-** _1(ir„
) FOR MATHfW CAREY,   X '*  *"U^
PRINTED
   DEC£M. 12, M.Scic.XCIX.
 
9 / 2 ^' 
c 
 
ADVERTISEMENT
TRANSLATOR.
         1HE very high character which Mr.
 Lavoifier has fo defervedly acquired as a chemical
 philofopher, and the great revolution which he
 has effected in  the theory of chemiftry,  had long
 made  it much  defired by all the cultivators of
 phyfical fcience, to have a connected account of
 his difcoveries,  and thofe of other chemical philo-
 sophers,  on which his  opinions are founded,
 together with an accurate expofition of the new
 theory, or rather of the regular concatenation of
 fefts, which he has eftablifhed, in confequence of
 thefe difcoveries,  made by himfelf  and others.
 For the performance of this arduous undertaking^
 no one could poffibly be better qualified than Mr!
Lavoifier himfelf.   He was not only thoroughly
converfant  in the  difcoveries  of  other philofo-
phers,  having,  with infinite pains,  repeated all
their important experiments,  and fo  varied moft
of them as to  bring their refults into  a much
                      b 
vi
ADVER TISEMENT.
clearer view, but-was himfelf the author of many
important difcoveries.  The hiftory, therefore, of
thefe difcoveries, and their proper arrangement,
for conveying an  exaft idea of the new theory
which he  had deduced from them,  could not,
certainly, have been given to the world fo well,
or with fo much propriety, by any other perfon.

   This  great defideratum in  the  hiftory  and
fcience of chemiftry, was accompliihed in the year
1789, by  the  publication of the Elements  of
Chemiftry by Mr. Lavoifier;  and a  copy of that
excellent work having fallen accidentally into the
hands of the tranflator, he was eager to give it
to the public in Englifh.   He has received great
fatisfa&ion from  the  favourable reception which
has been given to his firft  attempt  to merit  the
favour of the public;  and, whatever hefitation
he may have originally felt, two former editions
being completely exhaufted,  is  a fufficient  in-
ducement for bringing forward a new one.

   A new edition of the original having appeared
at Paris in winter 1792-3,  expe&ations  were
formed  that the author might have made  confi-
derable improvements; but from a correfpondence
with Mr. Lavoifier, the tranflator is enabled  to
fay,  that the new edition, having been printed
without his knowledge,  is entirely a tranfeript
from the former. 
ADVERTISEMENT.
vii
    Some very  material  additions,  though  not'
 numerous, have been made by the tranflator in
 this edition, relative  to certain difcoveries which
 have taken place in fome parts of chemiftry fince
 the publication of  the original; but as thefe are
 all diftinttly marked in their proper places in the
 courfe of the work, it is not neceffary to enume-
 rate them here.

   In  the original, Mr. Lavoifier employs  the
 fcale of Reaumur's thermometer, for defcribing
 the degrees of temperature  in his experiments:
 In the fecond and third edition of this tranflation,
 thefe  are uniformly transferred into their corref-
 pondent degrees on the fcale of Fahrenheit, which
 latter  is  univerfally ufed by the Britifh philofo-
 phers.  The weights employed by Mr. Lavoifier
 for detailing the ingredients and refults  of  his
 various experiments, are, in the original, expreffed
 in the cuftomary aliquot parts of the Paris pound,
poids de marc, which  is divided very differently
 from the Englifh pound, either troy or averdu-
pois:  To render thefe weights fully  intelligible
to the Britifh reader, they are all,  in this edition,
reduced to decimal  fractions of the pound, which
will ferve for all denominations.

  In the courfe of the tranflation, feveral explana.
tory notes are added ;  principally for the purpofe
of rendering the doftrines of  the author  more 
viii
ADVER TISEMENT.
readily underftood by beginners,  and by thofe
who have only  been  accuftomed to  the  old
language of chemiftry : In confequence, however,
of the perfpicuity of the author,  much fewer of
thefe were found neceffary than might have been
expe&ed from the comprehenfive  nature of the
work.   It was intended by the author to convey
a general view of the new chemical theory, rather
than to give a  fyftem of chemiftry; yet fuch is
the excellence of its plan  and execution, that,
with thefe limited intentions,  it is the beft body
of chemical philofophy extant.

   In a frnall number of places, the tranflator has
taken the liberty of throwing to the bottom of
the page, in notes, fome parenthetical expreffions,
not dire&ly connected with the fubje£r, which,
in their original place, rather tended  to confufe
the fenfe:  Thefe, and the original notes of the
author, are diftinguifhed by the letter A;  and
to thofe which the tranflator has ventured to add,
the letter T is fubjoined. Some difcoveries, which
have  been made in various  parts of  chemiftry
fince the publication of the original,  are added
in this tranflation  in their proper places.

   Mr. Lavoifier has given, in an appendix, feveral
very ufeful tables, for facilitating the calculations
now neceffary in  the advanced ft ate of modern
chemiftry, wherein the moft fcrupulous accuracy 
ADVERTISEMENT.
ix
 is required:  Thefe  are  now  as  indifpenfibly
 requifite to the operations of the chemical philofo-
 pher,as the Ephemerides, and Nautical Almanacs,
 and Logarithmic Tables,  are to the Navigator,
 Aftronomer, and Geometrician. Thefe tables are
 all retained  in this tranflation ; being, however,
 reduced to  the ftandards of  Britifh weights and
 meafures, with proper rules for making the necef-
 fary convcrfions from the  weights  and  meafures
 of France: And the tranflator is proud to acknow-
 ledge his obligations to  the  learned  Profeffor
 of Natural  Philofophy in  the  Univerfity  of
 Edinburgh,  and to his  friend Dr. Rotheram*,
 who kindly fupplied him with the neceffary infor-
 mation, and took the  trouble of making a number
 of very laborious calculations, for this purpofe.
 With the  fame affiftance,  feveral very ufeful
 additional tables have been  given in the Appendix,
 which need  not be here enumerated, as they will
 diftin&ly appear in their  proper places.


         POSTSCRIPT to the Third Edition.

   THE Philofophical world has now infinitely to
 deplore the  tragical and untimely death of the
 great Lavoisier ; who has left a rare example of

  * Formerly Affiflant to Dr. Black, Profeffor of Chemiftry
in the Univerfity of Edinburgh, and now Profeffor of Natural
Philofophy in the Univerfity of St.  Andrew's.
i* 
ADVER TISEMENT.
        fplendid talents and great wealth,  at  the fame
        time immerfed in numerous and important public
        employments,  which he executed with  diligent
        intelligence, and devoting his princely fortune and
        vaft abilities to the fedulous cultivation and mod
        fuccefsful improvement of  the Sciences.   If the
        fanguinary tyranny of  the monfter Robefpierre
        had committed only that outrage  againft eternal
        Juftice, a fucceeding age  of the  moft  perfect
        government  would  fcarcely  have  fufficed,  to
        France and to the  world, to repair the prodigious
        injury  that lofs has produced to chemiftry, and to
        all the fciences and economical arts with which it
        is conne&ed.

          Had Lavoifier lived, as  expreffed in a letter
        received  from him by the  Tranflator a fhort
        while before his maflacre, it was his intention to
        have republifhed thefe  Elements  in an entirely
        new form,  compofing  a  complete  Syftem  of
        Philofophical  Chemiftry : And, as a mark of his
        fatisfa&ion with the fidelity of this tranflation,
       he propofed to have conveyed to the Tranflator,
       flieet by fheet as it fhould  come from the prefs,
       that new and invaluable work, alas!  now  for
       ever loft.

/'';/a->  " ?~fw-1£*<«~   Yi ty fy****&-«-*3  '*'?)"**:"_>
//,. 
PREFACE
  or TH E


AUTHOR.
       Wh E N I began the following Work,
my only objeft was  to extend and explain more
fully the Memoir whichlread at the public meeting
of the Academy of Sciences in the month of April
1787, on the neceffity of reforming and completing
the Nomenclature of Chemiftry. While engaged
in this employment, I perceived, better than I had
ever done before, the juftice  of the following
maxims of the Abbe  de Condillac,'in his fyftem of
Logic, and fome other of his works.

  " We think  only  through the  medium of
iC words.—Languages are true analytical methods.
" —Algebra, which is adapted to its purpofe in
<c every fpecies  of expreffion, in the moft fimple,
" moft exaft, and beft manner poflible, is at the
" fame time a language and an analytical method.
" —The art of reafoning  is nothing more than
" a language wejl arranged." 
xii
PREFACE.
   Thus, while I thought myfelf employed only in
 forming  a Nomenclature,  and while I propofed
 to  myfelf nothing  more  than  to  improve the
 chemical language, my work transformed itfelf by
 degrees, without my being able to prevent it, into
 a treatife upon the Elements of Chemiftry.

   TheimpoffibilityoffeparatingtheNomenclature
 of a fcience from the fcience itfelf,  is owing to this,
 that every branch of phyfical fcience muft confift
 of three things; the feries of facts which are the
 objects of the fcience; the ideas which repre-
 fent thefe fa&s;  and the  words  by which thefe
ideas  are  expreffed.  Like three impreffions of
 the fame feal, the word ought to produce the idea,
 and the idea to  be a picture of  the fact.   And
 as  ideas   are preferved and  communicated by
 means of words, it neceffarily  follows, that we
 cannot improve the language of any fcience, with-
 out at the fame time improving the fcience itfelf;
 neither can we, on  the other hand, improve a
 fcience, without improving the language or no-
 menclature which belongs to it. However  certain
 the facts  of any  fcience may be, and however
juft the ideas we may have formed of thefe facts,
 we can  only  communicate falfe or  imperfect
 impreffions of thefe ideas  to others,  while we
 want  words by which  they may  be properly
 expreffed. 
PREFACE.
X1U
   To thofe who will  confider it with  attention,
the firft part of this treatife will afford frequent
proofs of the truth of thefe obfervations.   But as,
in the conduct of my work, I have been obliged
to obferve an order  of  arrangement  effentially
differing from  what  has been  adopted in any
other chemical work yet publifhed,  it is proper
that I fhould explain the motives which have led
me to adopt that arrangement.

   It is  a maxim univerfally admitted in Geome-
try, and indeed in  every branch of  knowledge,
that, in the progrefs of inveftigation, we fhould
proceed from known  facts to what is unknown.
In early infancy, our ideas fpring from our wants,
the fenfation of  want exciting  the idea of the
object by which it  is  to be  gratified.   In this
manner, from a feries of fenfations, obfervations,
and analyfes,  a fucceflive train of ideas arifes, fo
linked together,  that an attentive obferver may
trace back, to a certain point, the order and
connection of  the whole fum of human know-
ledge.

   When we begin  the ftudy of any fcience, wc
are in a fituation, refpecting that fcience, fimilar
to children ; and the courfe by which we have to
advance, is precifely the fame which Nature follov/s
in the formation of  their ideas.   In a child, the
idea is merely an effect produced by a fenfation 5
                      c 
xiv-
PREFACE.
 and, in the fame manner, in commencing the ftudy
 of a phyfiVal fcience,  we ought to form no idea
 but what is a neceffary confequence,  and imme-
 diate  effect, of an  experiment or obfervation.
 Befides, he who enters upon the career of fcience,
 is in  a lefs advantageous fituation  than a child
 who is acquiring his firft ideas.  To the child,
 Nature gives  various means  of rectifying any
 miftakes  he may commit reflecting the  falutary
 or hurtful  qualities of the objects which furround
 him.   On every  occafion  his  judgments are
 corrected by experience; want and pain are the
 neceffary  confequences arifing  from falfe judg-
 ment ; gratification and pleafure are  producedby
judging aright.  Under fuch mafters,  we cannot
 fail to  become well informed;  and we foon learn
 to reafon  juftly, when want and  pain  are the
 neceffary confequences of a contrary conduft.

   In the ftudy and practice  of the fciences it is
entirely different;  the falfe judgments we may
form neither affect our exiftence nor our welfare ;
and we are not compelled by any phyfical neceflity
to correal: them.  Imagination,  on the contrary,
which  is ever wandering  beyond  the  bounds of
truth,  joined to felf-love  and that felf-confidence
we are fo  apt  to  indulge, prompt us to draw
coriclufions which  are  not immediately  derived
from facts; fo that we become in fbme meafure
interefted in deceiving ourfelves.   Hence it is by 
                 PREFACE.               xt

no means furprifing, that, in the fcience of phyfics
in general, men have fo often formed fuppofitions,
inftead of drawing  conclufions.  Thefe fuppofi-
tions, handed down from  one age  to another,
acquire additional weight from the authorities by
which they  are  fupported, till  at  laft they are
received, even by men of genius, as fundamental
truths.

  The only method of preventing  fuch errors
from taking place, and of correcting them when
formed, is to reftrain and  fimplify our reafoning
as much as poffible.  This depends entirely on
ourfelves, and the neglect of it is the only fource
of our miftakes.  We muft truft to  nothing but
facts: Thefe are prefented to us by Nature, and
cannot deceive.   We ought, in every inftance,
to fubmit our reafoning to the teft of experiment,
and never to fearch for truth, but by the natural
road of experiment and obfervation.   Thus ma-
thematicians obtain the folution of a  problem, by
the mere arrangement of data,  and by reducing
their reafoning  to fuch fimple Heps,  and to con-
clufions (o very obvious, as never to lofe fight of
the evidence which guides them.

  Thoroughly convinced of thefe truths, I have
impofed upon myfelf, as a law, never to  advance
but from what  is known to what is unknown;
never to form any  conclufion which is  not  an 
xvi
PREFACE.
immediate confequence neceffarily flowing from
obfervation.  and  experiment ;  and  always  to
arrange the facts, and the conclufions which  are
drawn from them, in fuch an order as fhall render
it moft eafy for beginners in the ftudy of chemiftry
thoroughly to underftand  them.  Hence I have
been  obliged to depart from the order  ufually
obferved in courfes of lectures and treatifes upon
chemiftry; which always affume the firft principles
of the fcience as known, whereas the pupil or the
reader fhould never be fuppofed to know them
till they  have  been  explained in  fubfequent
leffons.  In almoft every inftance, chemical authors
and lecturers begin by treating of the elements of
matter, and by  explaining the table of affinities;
without confidering that,  in fo doing,  they mud
bring the principal phenomena of chemiftry into
view at the very outfet: They make ufe of terms
which have not been defined,  and  fuppofe  the
fcience to be underftood by the very perfons they
are only beginning to teach.

   It ought  likewife to be confidered, that very
little  of chemiftry can be learned in a firft courfe,
which is hardly fufficient to make the language of
the fcience familiar  to the ears, or the apparatus
familiar  to the  eyes.   It  is almoft impoflible to
become a chemift in Iefs than three or four years
of conftant application, 
                  PREFACE.              xvii

   Thefe  inconveniences are occafioned,  not  fo
 much by the nature of the fubject, as by the
 method of teaching it; and, to avoid them, I was
 chiefly induced to adopt a new arrangement  of
 chemiftry, which appeared to be more confonant
 to the order of Nature.  I acknowledge, however,
 that  in thus endeavouring to avoid difficulties  of
 one kind, I  have  found myfelf involved in others
 of a different fpecies,  fome of which I have not
 been able to remove; but I am perfuaded,  that
 fuch as remain do not arife from the nature of the
 order I have adopted, but are rather confequences
 of  the imperfection  under which  chemiftry ftill
 labours.   This fcience  has many chafms,  which
 interrupt  the feries of facts, and often render  it
 extremely difficult to reconcile thefe with each
 other. It has not, like the elements of geometry,
 the  advantage of being a  complete fcience, the
 parts of which are all clofely connected together.
 Its actual  progrefs, however, is fo rapid, and the
 facts, under the modern doctrine, have affumed fo
 happy an  arrangement, that we have ground to
 hope,  even in our own times, to fee it approach
 near to the high eft ftate of perfection of which  it
 is fufceptible.

  The rigorous  law from  which I have  never
 deviated,  of forming no conclufions which  are
not fully warranted by experiment, and of never
fupplying the abfence of facts, has prevented me 
XV111
PREFACE.
 from comprehending  in this work the branch of
 chemiftry which treats of affinities, although it is
 perhaps the beft calculated of any part of chemiftry
 for  being  reduced into a  completely fyftematic
 body.   Meffrs. Geoffroy,  Gellert,  Bergman,
 Scheele, De Morveau, Kirwan, and many others,
 have collected a great number of particular facts
 upon this fubject, which only wait for a proper
 arrangement.   But the  principal data are ftill
 wanting, or, at leaft, thofe we have are either
 not fufficiently defined, or not fufficiently proved,
 to become  the foundation for fo very important a
 branch of chemiftry. This fcience of affinities, or
 elective attractions, holds  the  fame place with
 regard to the other branches of chemiftry, that
 the higher or tranfcendental geometry does with
 refpect to the fimpler and elementary part.  And
 I thought it improper  to involve thofe fimple and
plain elements, which  I flatter myfelf the great eft
part of my readers will eafily underftand,  in the
obfcurities  and  difficulties which ftill attend that
other very ufeful and neceffary branch of chemical
fcience.

  Perhaps  a fentiment of felfrlove may,  without
my perceiving it, have given additional force to
thefe reflexions.  Mr. de Morveau  is at  prefent
engaged  in publifliing the  article Affinity in the
Methodical Encyclopaedia: and I had more reafons
than one to decline entering upon a work in \\ hich
he is employed. 
PREFACE.               xix
   It will, no doubt, be a matter of furprife, that
in a treatife upon the elements of chemiftry, there
fhould be  no chapter on  the conftituent and
elementary parts of  matter;  but  I  may  here
obferve, that the fondnefs for reducing  all the
bodies in  nature  to three or  four elements,
proceeds from a prejudice which  has defcended
to us from the Greek Philofophers.   The notion
of four elements, which, by the variety of  their
proportions, compofe all the known fubftances in
nature, is a mere hypothefis, affumed long before
the firft principles of  experimental philofophy or
of chemiftry had any exiftence.   In thofe days,
without poffeffing facts, they framed fyftems; while
we, who have collected fafts, feem determined to
reject even thefe, when they do not agree with
our prejudices.  The authority of thofe fathers of
human philofophy ftill carry great weight: and
there is reafon to fear that it will bear hard  even
upon generations yet to come.

   It  is very  remarkable,  notwithftanding  the
number of philofophical chemifts who have fup-
ported the doctrine of the four elements,  that
there is not one who has not been led,  by the
evidence of facts, to admit a greater number of
elements  into  their  theory.   The firft chemical
authors, after  the revival of letters, confidered
fulphur and fait as elementary fubftances, entering
into the compofition  of a great number of bodies. 
XX
PREFACE.
 Hence,  inftead  of  four,  they  admitted the
 exiftencetof fix elements.  Beccher affumed the
 exiftence  of three kinds  of earth j from the
 combination of which, in different proportions, he
 fuppofed all the varieties of raetallic fubftances to
 be produced.  Stahl  gave a new modification*^
 this  fyftem: And fucceeding chemifts have taken
 the  liberty to make or to imagine changes and
 additions of a fimilar  nature.  AH  thefe chemifts
 were carried along by the genius  of the age in
 which they lived, being fatisfied with  affertions
 inftead of proofs;  or, at leaft,  often admitting
 as proofs the flighteft  degrees  of probability,
 unfupported  by  that ftrictly rigorous  analyfis
 which is required by modern philofophy. ffUl
                                         " r i
   All that can  be faid upon the number and
 nature of elements, is, in my opinion, confined to
 difcuffions entirely of a metaphyfical nature.  The
fubject only furnifhes us with indefinite problems,
which may be folved in a thoufand different ways,
not one of which, in all probability, is confident
with nature.   I fhall, therefore, only add upon
this fubject, that if, by the term elements, we mean
to exprefs thofe  fimple  and indivifible  atoms of
which matter is compofed, it is extremely probable
we know toothing at all about them j but  if we-
apply the term elements or principles of bodies, to
exprefs our idea of  the laft point which analyfis
is capable of reaching, we mufl admit, as elements 
PREFACE.
XXI
all the fubftances into which we are able to reduce
bodies by decompofition.  Not that we are intitled
to affirm, that thefe fubftances which we  confider
as fimple, may not themfelves be compounded of
two, or even of a greater number of more fimple
principles.  But fince thefe principles cannot be
feparated, or rather fince we have not  hitherto
difcovered the means of feparating them,  they
aft with regard to us as fimple  fubftances,  and
we ought never  to fuppofe them compounded
until  experiment  and obfervation have proved
them to be fo.

   The foregoing  reflections upon the  progrefs
of chemical ideas naturally apply to  the words
by which thefe ideas are expreffed. Guided by the
work which, in the year 1787, Meffrs de Morveau,
Berthollet, de Fourcroy, and I compofed upon the
Nomenclature of Chemiftry, I have endeavoured,
as much as poffible, to denominate fimple bodies
by fimple terms:  and I was naturally led to name
thefe firft.  It will be recollected,  that we  were
obliged to retain that name of any fubftance  by
which it had been long known in the world, and
that in two  cafes  only we  took the liberty of
making  alterations; firft,  in  the  cafe of thofe
which were but newly difcovered, and had not yet
obtained names, or at leaft which had been known
but for a  fhort time, and the names of which had
not yet received the fanction of  the public ;  and
                      d 
xxii
PREFACE.
 fecondly, when the names which had been adopted,
 whether by the ancients or the moderns, appeared
 to us to exprefs evidently falfe ideas; when they
 confounded the fubftances,  to which they were
 applied,  with others  poffeffed   of different,
 or  perhaps oppofite  qualities.   We made  no
 fcruple,  in this cafe, of fubftituting other names
 in their room: and the greater number of thefe
 were borrowed from the Greek language.   We
 endeavoured  to frame them in  fuch a manner
 as  to  exprefs  the  moft general  and the moft
 characteriftic quality of the fubftances: and this
 was attended with the additional advantage both
 of affifting the memory of beginners,  who find it
 difficult to remember a new word which has no
 meaning,  and of  accuftoming them early to
 admit no word without connecting with it fome
 determinate idea.

   To  thofe bodies  which are  formed  by the
 union of feveral fimple fubftances,  we gave new
 names  compounded  in  fuch a manner as the
 nature of the  fubftances directed.   But, as the
number of known double combinations is already
 very confiderable, the only method by which we
 could avoid confufion,  was to divide thefe into
 claflls.   In the natural order of  ideas, the  name
 of  the clafs or genus is that which  expreffes a
 quality  common to a  great  number of  indivi-
duals :  the name of the fpecies,  on the contrary, 
PREFACE.
xxm
 expreffes a quality peculiar to certain individuals
 only.

   Thefe diftinctions are not, as fome may imagine,
 merely  metaphyfical, but  are  eftablifhed  by
 Nature. " A child," fays the Abbe de Condillac,
 " is taught to give the name tree to the firft which
 " is  pointed  out to  him.   The next tree he
 " fees prefents the fame idea; and he gives it the
 " fame name.   This he does likewife to a third
 " and a fourth; till at laft the word tree, which
 " he at firft applied  to  an individual, comes  to
 " be employed by him as the name of a clafs or
 " a genus; it  becomes an abftract idea,  which
 " comprehends all trees in general.  But when he
 " learns that all  trees do not ferve the  fame
 " purpofe, that they do not all produce the fame
 " kind  of fruit,  he  foon diftinguiflies them by
 " fpecific and particular names."  This is the
 logic of all the fciences,  and is  very naturally
 applicable to chemiftry.

   The acids,  for example, are compounded of
 two fubftances,  which  we  confideras  fimple.
 The one conftitutes acidity, and is common to all
 acids:  and, from this fubftance, the name of the
 clafs or the genus ought to be taken. The other
 is peculiar to each acid,  and diftinguiflies it from
 the reft:  and from this fubftance is to be taken
the name of the fpecies.   But,  in the greater 
xxiv
PREFACE.
number of acids,  thefe two conftituent elements,
the acidifying principle, and that which it acidifies,
may exift in different proportions, conftituting
all the poffible points of equilibrium or of fatura-
tion.   This  is the cafe in the fulphuric and the
fulphurous acids:  and thefe two ftates of. the fame
acid we have marked by varying the  termination
of the fpecific name.

   Metallic fubftances which have been expofed to
the joint action of the air and of fire, lofe their
metallic luftre, increafe in weight, and affume an
earthy appearance.   In this ftate, like the acids,
they  are  compounded of a  principle which is
common to all, and of one which is  peculiar to
each.   In the fame, way, therefore, we have
thought proper to clafs  them under a  generic
name, derived from the common principle; for
which purpofe, we have adopted the term oxyd;
and we diftingufh them from each other by the par-
ticular name of the metal  to which each belongs;

   Combuftible fubftances, which, in acids  and
metallic oxyds, are fpecific and particular prin-
ciples,  are capable of becoming, in  their turn,
common principles of a  great number of com-
pounds. The fulphurous  combinations have been
long  the  only known ones in this kind.   Now,
however, we know,  from  the  experiments of
 Meffrs Vandermonde, Monge,  and Berthollet, 
PREFACE.
XXT
that carbon may be combined with  iron, and
perhaps  with feveral  other  metals;   and that
from this combination, according to the propor-
tions, may be produced  fteel, plumbago,  &c.
We know likewife,  from  the experiments of
M. Pelletier, that phofphorus may be combined
with'a great number of metallic fubftances. Thefe
different combinations we  have claffed  under
generic names taken from the common fubftance,
with a  termination which marks this analogy,
fpecifying them by another name taken from that
fubftance which is proper to each.

   The nomenclature of bodies compounded of
three fimple  fubftances was  attended with ftill
greater  difficulty; not only on account of their
number, but  particularly, becaufe  we  cannot
exprefs  the nature of their conftituent principles
without  employing  more compound names.  In
the bodies which  form this clafs,  fuch as the
neutral falts,  for  inftance, we  had  to confider,
i ft, The acidifying principle, which is common
to them all;  2d, The acidifiable principle which
conftitutes their peculiar acid ; 3d,  The faline,
earthy,  or metallic  bafis, which determines the
particular fpecies of fait.  Here we derived the
name of each clafs of falts from the name of the
acidifiable principle common to all the individuals
of  that clafs; and  diftiuguiflied each  fpecies. by
the name of its peculiar faline, earthy, or metallic
bafis. 
xxvi              PREFACE.
    A felt, though compounded of the fame three
  principles, may, neverthelefs, by the mere diffe-
  rence of their proportion, be in three different
  ftates,of faturation.   The nomenclature we have
  adopted would  have been defective, had it  not
  expreffed thefe different ftates: and this we attained
  chiefly by changes of termination uniformly applied
  to the fame ftate of the different falts.

    In fhort,  we have  advanced fo far, that from
  the  name alone  may be inftantly found what  the
  combuftible fubftance is which enters into  any
  combination;  whether that combuftible fubftance
  be combined with the acidifying principle,  and
  in what  proportion;  what  is the  ftate of  the
  acid; with what bafis it is united ;  whether the
 faturation be exact, or whether the acid or the
 bafis be in excefs.

   It  may eafily  be fuppofed,  that  it was  not
 poffible to attain all thefe different objeas without
 departing, in  fome inftances,  from eftablifhed
 cuftom,  and adopting terms which, at firft fight,
 may  appear  uncouth  and barbarous.  But  we
 confidered that the ear is foon habituated to new
 words, efpecially  when they  are conneaed with
 a general and rational  fyftem.  The  names,
 befides, which  were formerly employed, fuch  as
powder of algaroth, fait  of alembroth, pompholix,
phagadenic water,  turbith  mineral, colcothar, and 
PREFACE.
xxVii
many others, were neither lefs barbarous nor lefs
uncommon.   It required a great deal of praaice,
and no fmall degree of memory, to recollea the
fubftances to which they were applied;  much
more to recollea* the  genus of combination to
which they belonged.   The names of oil of tartar
per deUquium, oil of vitriol, butter of arfenic and
of antimony, flowers of zinc,  &c. were ftill more
improper, becaufe  they fuggefted falfe ideas;  for,
in the whole mineral  kingdom, and particularly
in the metallic clafs, there exifts no fuch thing as
butters, oils, or flowers.  In fhort,  the fubftances
to whkh thefe fallacious  names were given, are
rank poifons.

   When we publifhed our effay on the Nomen-
clature  of Chemiftry, we were reproached for
having changed the language which was fpoken
by our  mafters,  which they ftamped with their
authority, and  have handed down to us.   But
thofe who  reproach us  on this account,  have
forgotten that Bergman and Macquer urged us to
make this  reformation:  In  a letter which  the
learned Profeffor of Upfal, M. Bergman, wrote,
a fhort time before he died,  to Mr Morveau, he
bids  him fpare no improper names;  thofe who arc
learned, wilUalways he learned; and thofe who are
ignorant will thus learn fooner. 
XXviii
PREFACE.
   There is an objeaion  to this work, which is
 peihaps better founded;  that  I have given no
 account of the opinions of thofe who have gone
 before  me, and have only ftated my own without
 examining thofe of others.  By this I have been
 prevented from doing that juftice to my affociatesj
 and more efpecially to  foreign chemifts, which I
 wifhed to render them. But I befeech the reader to
 confider, that, if I had filled an elementary work
 with a  multitude of quotations,  if I had allowed
 myfelf  to enter into  long differtations on the
 hiftory of the fcience, and the works of thofe who
 have ftudied it, I muft have loft fight of the true
 objea I had in view, and fhould have produced a
 work extremely tirefome to beginners.

   It is not the  hiftory  of  the fcience, or of  the
 human  mind,  that we are to attempt  in  an
 elementary treatife.  Our only aim fhould be eafe
 and perfpicuity; and with the utmoft care to keep
 every thing out of view which may draw afide the
 attention of the ftudent.   It is a road which we
 fhould be continually rendering more fmoothj and
 from which we muft endeavour  to remove every
 obftacle which can occafion delay.  The fcienees,
from their own nature, prefent a fufficient number
of difficulties, though we add not thofe which are
foreign.  But,  befides this, chemifts  will eafily
perceive, that,  in the firft part of my work, I
make very little ufe of any experiments but thofe 
PREFACE.
x&ix
 which were made by myfelf.  If at any time I
 have, adopted, without  acknowledgements  tjoe
 experiments or the opinions of M. Bertjiollet, M.
 Fourcroy,  M. de la Place, M. Monge, or, in
 general, of any of thofe whofe principles are,fhe
 feme with my own, it is owing to thfc circumftance,
 that, frequent intercourfe, an4 the habit of com-
 municating our ideas, oar obfervations,  and our
 Ways of thinking, to each othe/, have eftablifhed
 between us a fort of community of qpinions, in
 which it is often difficult for every one to know
 his own-

   Thefe remarks on  the order which I thought
 myfelf obliged to follow in the arrangement of
 proofs and ideas,  are to be applied only to the
 fjrft part of this work.  It is the only one which
 CjQntajns, £he  general fum of the doctrine I have
 adopted, and  to which I wifhed to  give a form
 completely elementary.

   The fecond part is compofed chiefly of tables
 of the nomenclature  of  the  neutral falts.   To
 thefe I have only added general explanations, the
 objea of which is to point out the moft fimple
 proceffes for  obtaining the different  kinds of
known acids, di This part contains nothing which
 I can ca^ my own;  and prefents only a  very
fhort abridgement of the refults of thefe proceffes,
extraaed from the works of different authors.
e 
  rtxx              PREFACE.

    In the third part, I have given a defcriptioily
  in detail, of  all the operations conneaed with
  modern chemiftry.  I have long thought that a
  work of this kind was  much wanted: and I am
"  convinced it will  not be without  its ufe.   The
  method of performing experiments, and particu-
  larly thofe of modern chemiftry, is not fo generally
  known  as it ought to be: and had  I, in  the
  different memoirs  which I have prefented to the
  Academy, been more particular in the detail of
  the manipulations of my experiments, it is probable
  I fhould have made myfelf better underftood,  and
  the fcience might have made a more rapid progrefs.
  The order for the different matters contained in
  this third part appears to me almoft arbitrary:
  and the only one I have obferved,  is to  clafs
  together, in each of the chapters of  which  it is
  compofed, thofe  operations which are moft con-
  neaed with one another.  I need hardly mention,
  that this  part could not be borrowed from  any
  other work, and that,  in the  principal articles it
  contains,  I  could  not derive afliftance from  any
  thing but the experiments which I  have  made
  myfelf.

    I {hall conclude this preface by tranfcribing,
  literally,  fome  obfervations  of the  Abbe  de
  Condiliac, which  I  think  defcribe, with a good
  deal of truth,  the ftate of Chemiftry at a period
  not far diftant from our own.  Thefe obfervations 
PREFACE.
xxxi
were made on a different fubjea; but they will
not on  this  account,  have lefs  force;  if the
application of them be juft.

  c Inftead of applying obfervation to the things
6 we wifhed  to know, we have chofen rather to
' imagine them.  Advancing from one ill-founded
6 fuppofition to another, we have at laft bewildered
6 ourfelves amid a multitude of errors.   Thefe
c errors, becoming prejudices,  are,  of courfe,
 6 adopted as principles, and we  thus bewilder
c ourfelves more and more.  The method,  too,
' by which we condua our reafonjngs is abfurd.
£ We abufe words which we do not underftand,
c and call this the art of reafoning.  When matters
c have been brought this length, when errors
' have been  thus accumulated, there is but one
' remedy, by which order can be reftored to the
' faculty of  thinking;  this  is,  to forget all that
c we have learned, to  trace back our  ideas to
' their fource,  to follow the train in which they
' rife, and,  as  Lord Bacon fays, to frame the
c human underftanding anew.

  ' This remedy becomes  the more difficult, in
6 proportion  as  we  think  ourfelves the more
' learned.  Might-it not be thought, that works
c which  treat of the fciences  with the  utmoft
c perfpicuity, and  with the greateft order  and
c pfecifion, muft be undcrftood  by every body ? 
Xxxii
PREFACE.
* The faa is, thofe who have never ftudied any
6 thing will underftand them better than thofe who
* have ftudied a great deal, and efpecially than
6 thofe who have written a great deal.'

  In another place, the Abbe de Condillac adds :
' But,notwithstanding,thefciences have improved,
c becaufe  philofophers have applied themfelves
6 with more  attention than  formerly to obferve
' nature, and have communicated to their language
* that precifioh  and  accuracy which fhey have
' employed in their obfervations.—-By correaing
6 their language, they have reafoned better.' 
CONTENTS.
««■*]
             PART  FIRST.

Of the Formation and Decompoution of Aeri-
   form Fluids—of the Combuftion of Simple
   Bodies—and the Formation of Acids,
                                          Page 49
CHAP. I.—Of the Combinations of Caloric, and the
   Formation of Elaftic Aeriform Fluids or Gaffes,    ibid.
CHAP. II.—General Views relative to the Formation
   and Compofition of our Atmofphere,               74
CHAP. Ill___Analyfis of Atmofpheric Air, ahd its
  Divifion into two Elaftic Fluids; one fit for Refpiration,
  the other incapable of being Refpired,              80
CHAP. IV.—Nomenclature of the feveral Conflituent
   Parts of Atmofpheric Air,                        97
CHAP. V.—Of the Decompofition of Oxygen Gas by
   Sulphur, Phofphorus, and Carbon, and of the Forma-
   tion of Acids in general,                        103
CHAP. VI.—Of the Nomenclature of Acids in general,
  and particularly  of  thofe drawn from  Nitre  and
   Sea-Salt,                                      116
CHAP. VII.—Of  the Decompofition of Oxygen Gas
   by means  of Metals,  and  the Formation  of Metallic
   Oxyds,                                       129
CHAP. VIII—Of the  Radical Principle of Water,
  and of its Decompofition by Charcoal and Iron,    135 
XXXIV
CONTENTS.
  CHAP. IX—Of the Quantities of Caloric difengaged
    from different  Species of Combuftion,        Page  150
  Combuftion of Phofphorus,                         x ?4
  SECT. I.—Combuftion of Charcoal,                jrr
  SECT. II.—Combuftion  of Hydrogen Gas,          ib.
  SECT. III.—Formation  of Nitric Acid,             156
  SECT. IV—Combuftion of Wax,                 I59
  SECT. V—Combuftion of Olive Oil,               160
  CHAP. X.—Of the Combinations of Combuftible Sub-
    ftances with each other,                          rg^
  CHAP. XI.—Obfervations upon Oxyds and Acids with
    feveral Bafes, and upon the Compofition of Animal
    and Vegetable Subftances,                        x 7o
 CHAP. XII.—Of the Decompofition of Vegetable and
   Animal Subftances by the A&ion of Fire,           178
 CHAP. XIII—Of the Decompofition of  Vegetable
   Oxyds by the Vinous Fermentation,              2g-
 CHAP. XIV—Of the  Putrefactive Fermentation,    198
 CHAP. XV—Of the Acetous Fermentation,       203
 CHAP. XVI.—Of the Formation of Neutral Salts, and
   of their Bafes,                                 2og
 SECT. I.—Of Potato,                           2o8
 SECT. II.—Of Soda,                            2I2
 SECT. III.—Of Ammoniac,                      2j.
 SECT. IV—Of Lime, Magnefia, Barytes, and ArgiU;
  and of Strontites,  a newly difcovered Earth,       21 c
 SECT. V—Of Metallic Bodies,                   2, J
SECT.  VI._Of the Metallic Nature of the  Earths,  220
CHAP. X\  II—Continuation of the Obfervations upon
  Salifiable Bafes, and the Formation of Neutral Salts,  220
TABLE of  all  the known Acids,                '    9 
CONTENTS.
xxxr
PART   II.
Of the Combinations of Acids with Salifiable
   Bafes,  and  of the  Formation  of Neutral
   Salts,                                Page  243
 INTRODUCTION,                             ib.
 TABLE of Simple Subftances,                    245
 SECT. I.—Obfervations upon Simple Subftances,    246
 TABLE of Compound Oxydable and Acidifiable Bafes, 249
 SECT. II.—Obfervations upon Compound Radicals,  250
, SECT. III.—Obfervations upon the Combinations of
   Light and Caloric with different Subftances,        252
 TABLE  of the Combinations of  Oxygen  with the
   Simple  Subftances, to face                      255
 SECT. IV.—Obfervations upon thefe Combinations,  255
 TABLE  of the Combinations  of Oxygen with Com-
   pound Radicals,                              260
 SECT. V.—Obfervations  upon thefe Combinations,  261
 TABLE  of the Combinations of Azot with the Simple
   Subftances,                                   264
 SECT. VI.—Obfervations upon thefe Combinations of
   Azot,                                       265
 TABLE of the Combinations of Hydrogen with Simple
   Subftances,                                   268
 SECT. VII.—Obfervations  upon  Hydrogen, and its
   Combinations,                                 269
 TABLE  of the Binary Combinations of Sulphur with
   the Simple Subftances,                          272
 SECT. VIII.—Obfervations on Sulphur, and its Com-
   binations,                                    273 
XXXVI
CONTENTS.
 TABLE of the Binary Combinations of Phofphorus with
    Simple Subftances,                         Page 274
 SECT. IX.—Obfervations on Phofphorus and its Com-
    binations,                                      275
 TABLE of the Binary Combinations of Carbon,     277
 SECT. X.—Obfervations upon Carbon and its Combi-
   nations,                                        278
 SECT. XI.—Obfervations upon the Muriatic, Fluoric,
   and Boracic Radicals and their Combinations,       279
 SECT. XII.—Obfervations upon the Combinations  of
   Metals with each other,                          280
 TABLE of the Combinations of Azot, in the State  of
   Nitrous Acid, with  the Salifiable  Bafes,            282
 TABLE of the Combinations of Azot, in the State  of
   Nitric Acid, with the Salifiable Bafes,              283
 SECT. XIII.—Obfervations  upon Nitrous and  Nitric
   Acids, and their Combinations with Salifiable Bafes,  284
 TABLE of the Combinations of Sulphuric Acid with
   the Salifiable Bafes,                              289
 SECT. XIV.—Obfervations upon Sulphuric Acid, and
   its Combinations,                      '           290
 TABLE of the Combinations of Sulphurous Acid,   293
 SECT. XV.—Obfervations upon Sulphurous Acid, and
   its Combinations with Salifiable Bafes,               294
 TABLE of the Combinations of Phofphorus and Phof-
   phoric Acids,                                   296
 SECT. XVI. — Obfervations upon Phofphorus and
   Phofphoric  Acids,  and  their Combinations  with
   Salifiable Bafes,                                 297
TABLE of the Combinations of Carbonic Acid,     299
SECT. XVII.—Obfervations upon Carbonic Acid, and
   its Combinations with Salifiable Bafes,             300
TABLE of the Combinations of Muriatic Acid,      302
TABLE of the Combinations of Oxygenated Muriatic
   Acid,                                         ^03 
CONTENTS.
xxxvii
SECT. XVIII.—Obfervations upon Muriatic and Oxy-
   genated Muriatic Acid,  and their Combinations with
   Salifiable Bafes,                           >Page 304
TABLE of the Combinations of Nitro Muriatic Acid, 307
SECT. XIX.—Obfervations upon Nitro Muriatic Acid,
   and its Combinations with Salifiable Bafes,          308
TABLE of the Combinations of Fluoric Acid,        310
SEQT. XX.^—Obfervations upon Fluoric Acid, and its
   Combinations with Salifiable Bafes,                 3 11
TABLE of the Combinations of Boracic Acid,        3.13
SECT. XXI.—Obfervations  upon  Boracic Acid,  and
   its Combinations with Salifiable Bafes,              314
TABLE of the Combinations of Arfeniac Acid,     317
 SECT. XXII.—Obfervations upon Arfeniac Acid, and
   its Combinations with Salifiable Bafes,             318
SECT. XXIII___Obfervations upon  Molybdic  Acid,
 .  and its Combinations with Acidifiable Bafes,         320
SECT. XKIV.—Obfervations upon Tungftic Acid, and
   its Combinations with Salifiable Bafes, and a Table of
   thefe in the G.dei  of their Affinity,                323
TABLE of  the Combinations of Tartarous Acid,     324
SECT. XXV.—Obfervations upon Tartarous Acid, and
   its Combinations with Salifiable Bafes,              325
SECT. XXVI.—Obfervations upon Mallic Acid,  and
   its Combinations with Salifiable Bafes,              327
TABLE of  the Combinations of Citric Acid         329
SECT. XXVII.—Obfervations upon Citric Acid,  and
   its Combinations with Salifiable Bafes,              330
TABLE of  the Combinations of Pyro-lignous Acid,  331
SECT.  XXVIII.-—Obfervations  upon  Pyro-lignous
   Acid, and its Combinations with Salifiable Bafes,   332
SECT. XXIX. — Obiervations upon  Pyro-tartarous
   Acid,  and  ks Combinations with  Salifiable Bafes,   ib.
TABLE of the Combinations of Pyro-mucous Acid,   334
SECT, XXX.—Obfervations  upon  Pyro-mucous Acid,
   and its Combinations with Salifiable Bafes,           335
                         f 
xxxvm
CONTENTS;.
TABLE of the Combinations of Oxalic Acid,  Page 33$
SECT. XXXI.—Obfervations upon Oxalic Acid, and
  its Combinations with Salifiable Bafes,             337
TABLE  of the Combinations  of Acetous  Acid,  to
  face                                            338
SECT. XXXII.—Obfervations upon Acetous Acid,
  and its Combinations with the Salifiable Bafes,      338
TABLE of the Combinations of Acetic Acid,       342
SECT. XXXIII.—Obfervations upon Acetic Acid,
  and its Combinations with Salifiable  Bafes,         343
TABLE of the Combinations of Succinic Acid,      344
SECT. XXXIV.—Obfervations upon Succinic Acid,
  and its Combinations with Salifiable  Bafes,         34^
SECT. XXXV.—Obfervations  upon Benzoic Acid,   ,
  and its Combinations with Salifiable  Bafes,         346
SECT. XXXVI.—Obfervations upon  Camphoric Acid,   ,
  and  its Combinations with  Salifiable Bafes,         347
SECT. XXXV11.—Obfervations  upon  Gallic Acid,
  and  its Combinations with Salifiable  Bafes,         348
SECT. XXXVIII.—Obfervations  upon Laclic Acid,
  aud  its Combinations with Salifiable  Bafes,         349
TABLE of the Combinations of Saccho-laftic Acid, 351
SECT. XXXIX. — Obfervations  upon Saccho-ladic
  Acid, and its Combination with Salifiable Bafes,   352
TABLE of the Combinations of Formic Acid,      353
SECT. XL.—Obfervations upon Formic Acid, and its
  Combinations with the Salifiable Bafes,            354
SECT. XL1.— Obfervations upon  the Bombic Acid,
  and its Combinations with Acidifiable Bafes,       355
TABLE of the Combinations of the Sebacic Acid,   356
SECT. XLI1.—Obfervations upon the Sebacic Acid,
  and  its Combinations  with  the Salifiable Bafes,     357
SECT. XLIII.—Obfervations upon  the Lithic Acid,
   and  its Combinations with  the  Salifiable  Bafes,    358
 TABLE of the Combinations of the  Prufi'C Acid,   359 
CONTENTS.
xxxix
SECT. XLIV.—-Obfervations upon the  Pruflic Acid,
  and its Combinations with the Salifiable Bafes,  Page 360
SECT. XLV.—Recapitulation of  the foregoing Ob-
  fervations on the  Acids and their Combinations,    361
TABLE of the Order of Affinities  of the Salifiable
  Bafes with  the feveral Acids,  fo far as  is hitherto
  known,                                       3^4
TABLE of the Nomenclature of the Neutral Salts,   366
                  PART  III.

Defcription of  the  Inftruments  and  Opera-
   tions of Chemiftry,                        569

INTRODUCTION,                              ib.
CHAP. I.—Of the  Inftruments neceffary for  deter-
   mining the Abfolute and Specific Gravities  of Solid
   and Liquid Bodies,                            373
CHAP. II__Of Gazometry,  «r the Meafurement of
   the Weight and Volume of Aeriform Subftances,    382
SECT. I__Of the Pneumato-chemical Apparatus,     ib.
SECT. II__Of the Gazometer,                   386
SECT. III.—Some other methods for  Meafuring the
   Volume of Gaffes,                             397
SECT. IV.—Of the method of Separating the different
   Gaffes from each other,                         401
6ECT. V__Of*the neceffary Corretfions of the Volume
  of Gaffes, according to the  Preffure of the Atmof-
   phere,                                        406
SECT. VI__Of the Correction relative to the Degrees
  of the Thermometer,                           413 
xl
CONTENTS.
SECT. VII—Example for Calculating the Corrections
   relative to the Variations of Preffure and Tempera-
   ture,                                    Page 415
SECT. VIII.—Method of determining the Weight of
   the different Gaffes,                             418
CHAP. III.—Defcription of the Calorimeter, or Ap-
   paratus for meafuring Caloric,                    421
CHAP. IV.—Of the Mechanical Operations for Divifion
   of Bodies,                                     434
SECT. I.—Of Trituration, Levigation,  and  Pulveri-
   zation,                                         ib.
SECT. II___Of Sifting and Warning Powdered Sub-
   ftances,                                       438
SECT. III.—Of Filtration,                      440
SECT. IV.—Of Decantation,                     442
CHAP. V.—Of  Chemical means for  Separating the
   Particles of Bodies from each other without Decom-
   pofition, and for Uniting them again,              444
SECT. I.—Of the Solution of Salts,               44^
SECT. II.—Of Lixiviation,                      450
SECT. III.—Of  Evaporation,                    452
SECT. IV.—Of Cryftallization,                   456
SECT. V__Of Simple Diftillation,                 461
SECT. VI___Of Sublimation,                     465
CHAP. VI.—Of Pneumato-chemical Diftillations, Me-
   tallic Diffolutions, and fome other Operations which
   require very Complicated Inftruments,             467
SECT.  I.—Of  Compound and  Pneumato-chemical
   Diftillations,                                    ib.
SECT. II.—Of Metallic Diffolutions,              475
SECT. III.—Apparatus neceffary in Experiments upon
   Vinous and Putrefactive  Fermentations,            478
SECT. IV.—Apparatus   for  the  Decompofition  of
   Water,                                       481 
CONTENTS.
3di
CHAP. VII.—Of the Compofition and Ufe of Lutes, 484
CHAP. VIII.—Of Operations  upon Combuftion and
  Deflagration,                                 491
SECT. I.—Of Combuftion in General,              ib.
SECT. II.—Of the Combuftion of Phofphorus,      495
SECT. III.—Of the Combuftion of Charcoal,      499
SECT. IV___Of the Combuftion of Oils,           503
SECT. V__Of the Combuftion of Alkohol,         51 o
SECT. VI___Of the Combuftion of Ether,          512
SECT. Vll__Of the Combuftion of Hydrogen Gas,
  and the Formation of Water,                   J14
SECT. VIII.—Of the Oxydation of Metals,        518
CHAP. IX__Of Deflagration,                   529
CHAP, X.—Of the Inftruments neceffary for Operating
  upon Bodies in very high Temperatures,           537
SECT. I.—OfFufion,                           ib.
SECT. II.—Of Furnaces,                       539
SECT. III.—Of increafing the  Aclion of Fire,  by
  ufing Oxygen Gas inftead of Atmofpheric Air,      55 r 
xffi               CONTENTS.
             APPENDIX.

 No. I.—Table for Converting Lines or Twelfth Parts
   of an Inch,  and Fractions of Lines,  into Decimal
   Fractions of the Inch,                      Page 557
No. II.—Table for Converting the Obferved Heights
   of Water in the Jars of the  Pneumato-Chemical
   Apparatus,  expreffed in Inches and Decimals, into
   Correfponding Heights  of Mercury,               558
No. III.—Table  for Converting the Ounce Meafures
   ufed by Dr Prieftley into French and Englifh Cubical
   Inches,                                        559
No. IV.—Additional.—Rule for Reducing the
   Degrees  of Reaumur's  and of the Swedifh Thermo-
   meter, into its correfponding Degrees of Fahrenheit's
   Scale,                                         560
No. V.—Additional.—Rules for Converting French
   Weights and  Meafures into correfpondent  Englifh
   Denominations,                                 562
No. VI. — Additional. — Rules for  reducing  the
   Swedifh  Weights  and Meafures,  ufed  by the  Cele-
   brated Bergman  and Scheele,  to Englifh Denomi-
   nations,                                        567
No. VII.—Table  of  the Weights  of  the  different
   Gaffes, at 28 French  Inches, or 29.84 Englifh inches
   barometrical preffure,  and at 10 (54.50) of tempera-
   ture,  expreffed in Englifh meafure and  Englifh Troy
   weight,                                        569
No. VIII.—Tables of the Specific Gravities of differ-
   ent Bodies,                                     570
No. IX.—Additional.—Rules  for Calculating the
   Abfolute Gravity in Englifh Troy Weight of a Cubic
   Foot  and Inch, Englifh Meafure, of any Subftance
  whofe Specific Gravity is known,                 584 
CONTENTS.
xliii
No. X.—Tables for Converting Ounces, Drams,  and
  Grains, Troy, into Decimals of the Troy Pound of
  12 ounces, and for Converting Decimals of the Pound
  Troy  into Ounces, &c.                     Page 587
No. XL—Table of the Englifh Cubical Inches  and
  Decimals correfponding to a determinate Troy Weight
  of Diftilled Water at the Temperature of 55°, calcu-
  lated from Everard's experiment,                  590
No. XII—Additional.—Table of the Comparative
  Heats of different Bodies, as afeertained by Crawford,
                                                59*
No. XIII.—-Additional.—Table  of the Ingredients
  in the Neutral Salts, as determined  by  Kirwan,     592 
 
     ELEMENTS

                   OF

CHEMISTRY
                PART  I.

 Of the Formation and Decompofition of Aeri-
   form Fluids—of the Combuftion of Simple
   Bodies—and of the Formation of Acids.


               CHAP.   I.

 Of the Combination of Caloric, and the Formation
           of Elajlic Aeriform Fluids.

     THAT  every  body, whether folid or fluid,
      is augmented in all its dimenfions by  any
increafe of its fenfible heat, was long ago fully
eftablifhed as a phyfical axiom, or univerfal pro-
portion, by the celebrated Boerhaave.  Such
facts as have been adduced, for controverting the
                    G 
5°
ELEMENTS
generality of this principle, offer only fallacious
refults,  or,  at leaft,  fuch as are fo complicated
with  foreign  circumftances, as to miflead the
judgment.   But, when we feparately  confider
the effects, fo as to deduce each from  the caufe
to which they feparately  belong,  it is  eafy  to
perceive, that the feparation of particles by heat
is a conftant and general law of nature.
   When we have heated a folid body to a cer-
tain degree, and  have  thereby caufed its  parti-
cles to feparate from each other, if we allow the
body to cool, its  particles again approach  each
other in the fame proportion in which they were
feparated  by the increafed temperature ; the bo-
dy returns  by  the fame  degrees  of  expanfion
through which  it before extended;   and,  if
brought back to the fame temperature  which it
poiTeffed at the  commencement  of the experi-
ment, it recovers exaclly the  fame dimenfions
which it formerly occupied.   We are ftill ve-
ry far from being able to produce the degree of
abfolute cold, or total deprivation of heat, being
unacquainted with any degree of coldnefs  which
we cannot  fuppofe capable of ftill  farther aug-
mentation.   Hence it follows,  that we are inca-
pable of caufing the  ultimate particles  of bodies
to approach each other  as near as poftible, and
that thefe  particles of bodies  do rot touch each
other in any ftate  hitherto   known.   Though 
OF  CHEMISTRY.
 this be a very lingular conclufion it is impoflible
 to be denied.
   It may be fuppofed, that, fince the particles of
 bodies are thus  continually impelled by heat to
 feparate from each other, they would  have no
 connection between  themfelves;  and  that, of
 confequence,  there could  be no folidity in na-
 ture, unlefs thefe  particles were  held  together
 by fome other  power  which  tended  to  unite
 them, and, fo to fpeak, to chain them together :
 This power,  whatever be its caufe, or manner
 of operation,  is named Attraction.
   Thus the particles of all bodies may be con-
 fidered as fubject to the action of  two oppofite
 powers, Repulfion  and   Attraction,  between
 which they remain  in equilibrio.  So long as the
 attractive force remains ftronger, the body muft
 continue in a ftate of folidity: but if, on the
 contrary, heat has fo far removed thefe  parti-
 cles fiam each  other, as to place them beyond
 the fphere of attraction, they  lofe the  cohefion
 they before had  with each  other, and the body
 ceafes to be folid.
   Water gives us a regular and conftant exam-
 ples of thefe facts.  Whilft below 32 ' of Fahren-
 heit's fcale*,  it  remains folid,  and is called ice.

 * Whenever the degr?e of hear occurs in the original,  it
is ftuted  by the  author ac-ording to Ileaii.i.ui's thermo- 
52
ELEMENTS
Above that degree  of temperature, its particles
being no longer held together by reciprocal at-
traction, it becomes liquid ; and, when we raife
its temperature above 212°, its particles, giving
way to the repulfion caufed by the heat,  affume
the ftate  of vapour or gas, and the water is
changed into an aeriform fluid.
   The fame may be  affirmed of all  bodies in
nature.   They are either folid, or liquid,  or in
the ftate  of elaftic  aeriform  vapour,  according
to the proportion  which takes  place between
the attractive  force inherent  in their particles,
and the repulfive  power of the heat acting upon
thefe; or, what amounts to the  fame thing, in
proportion to the degrees of heat to which they
are expofed.
   It is difficult to comprehend thefe phenome-
na, without admitting them  as the effects of a
real and  material fubftance,  or very  fubtile flu-
id, which, infinuating itfelf between the parti-
cles of bodies, feparates them from each other.
Even  allowing that the  exiftence of this fluid
may be hypothetical, we fhall fee in  the fequel,
that it explains the phenomena of nature in a
very fatisfactory manner.
   Thi: fubftance, whatever it is, being the  caufe

meter; but the tranflator has thought it m-^re conveni-
ent to ufe Fahrenheit's fcale, as more generally employ-
ed and underftood in Britain.—T. 
O F  C H E M I S T R Y.        53
of heat,  or, in other words, the fenfation which
we call warmth, being caufecl by the accumula-
tion of this  fubftance, we cannot, in ftrict lan-
guage, diftinguifh it  by the term heat, bccaufe
the fame name would then  very improperly ex-
prefs both caufe and effect.   For this reafon, in
the memoir which I publifhed in 1777*, I gave
it  the  names of igneous fluid and matter of'fluid':
And,  fince that time, in the  work f publifhed
by Mr de Morveau, Mr Berthollet, Mr de Four-
croy,  and myfelf, upon the reformation of che-
mical nomenclature, we thought it  neceffary to
reject  all  periphraftic expreflions,  which both
lengthen  phyfical language, and render it lefs
diftinct,  and  which  even  frequently  do  not
convey fufficiently  juft  ideas of the object in-
tended.  Wherefore, we have diftinguifhed the
caufe of heat, or that  exquifitely  elaftic fluid
which  produces it,  by the term  of caloric.  Be-
fides, that this expreflion fulfils our object in the
fyftem which we have adopted, itpoffeffesthis far-
ther advantage, that it accords with every fpecies
of opinion ; fince, ftrictly fpeaking,  we are not
obliged to fuppofe this to be  a real fubftance,  it
being fufficient, as will more clearly appear in the
fequel  of this  work, that it be confidered as the

 * Collections of the French Academy of Sciences  for
that year, p. 420.
 f New Chemical Nomenclature. 
54
ELEME  NTS
repulfive caufe, whatever that may be, which fe-
parates the particles of matter from each other ;
fo that we are ftill at liberty to inveftigate its ef-
fects in an abftract and mathematical manner.
   In the prefent ftate of our knowledge, we  are
unable to determine whether light  be a  modifi-
cation of caloric, or caloric be,  on the  contra-
ry, a modification of light.  This,  however, is
indifputable,  that, in a fyftem where only deci-
ded facts are admiflible, and where we avoid, as
far as poffible, to fuppofe any thing  to be, that
is not really known to exift, we ought provision-
ally to diftinguifh, by diftinct terms, fuch things
as are known to produce different effects.   We
therefore  diftinguifh light from caloric ;  though
we do not therefore deny that thefe have certain
qualities  in common, and that, in certain  cir-
cumftances, they combine with other bodies al-
moft  in the fame manner, and produce, in part,
the fame effects.
   What I have already faid,  may  fuffice to de-
termine the idea affixed to the  word  caloric;
but   there remains  a  more  difficult attempt,
which is,  to  give a juft conception of the man-
ner  in  which  caloric acts upon  other bodies.
Since this fubtile matter  penetrates through the
pores of  all  known  fubftances—fince there are
no veffels through which it cannot efcape—and,
confequently, as there are none which are capa-
ble of retaining it—we  can  only  come at  the 
OF  CHEMISTRY.
55
knowledge of its properties by effects which are
fleeting and  difficultly  afcertainable.   It  is in
thofe things which we neither fee nor feel, that
it is efpecially neceffary to guard againft the ex-
travagancy of our imagination,  which for  ever
inclines to ftep beyond the bounds of truth, and
is very difficultly reftrained within  the  narrow
limits of facts.
  We have  already  feen, that  the  fame body
becomes folid,  or fluid, or aeriform, according
to the quantity of caloric by  which it is pene-
trated ; or, more ftrictly, according as the re-
pulfive force exerted by the  caloric is equal to,
ftronger, or weaker than, the attraction of the
particles of the body it acts upon.
  But, if thefe two powers only exifted,  bodies
would become liquid at an indivifible deo-ree of
the thermometer,  and would almoft inftantane-
oufly pafs from the folid ftate of aggregation  to
that  of aeriform elafticity.  Thus water,  for in-
ftance, at the very inftant when  it ceafes to be
ice, would begin  to boil, and would be tranf-
formed into an aeriform  fluid, having  its parti-
cles fcattered indefinitely through the furround-
ing fpace.  That this does not happen, muft de-
pend upon the action of fome third power.  The
preffure of the atmofphere prevents this fepara-
tion; and caufes the  water to remain in  the li-
quid ftate, until raifed to the temparature indica-
ted by 2i2Q on the fcale of Fahrenheit's thermo- 
56          E L E  M E  N  T S
 meter : the quantity of caloric which it receives
 in the lower temperatures  being infufficient to
 overcome the preffure of the atmofphere.
   Whence it appears, that, without  this atmo-
 fpheric preffure, we fhould not have any perma-
 nent liquid,  and fhould only fee  bodies in that
 ftate of exiftence in  the very inftant  of melt-
 ing ; for  the fmalleft additional caloric would
 then inftantly feparate their particles, and diffi-
 pate them through the furrounding medium.
 Befides, without this  atmofpheric preffure, we
 fhould not even have any proper aeriform fluids ;
 becaufe the  moment  the force of  attraction is
 overcome by the repulfive power of the caloric,
 the particles of bodies would feparate  themfelves
 indefinitely,  having nothing  to  give limits to
 their expanfion,  unlefs their own  gravity  might
 collect them together, fo as to form an  atmo-
 fphere.
  Simple reflection, upon the moft common ex-
 periments, is fufficient to  evince the  truth of
 thefe pofitions.    They  are more particularly
 proved  by the  following  experiment,  which I
 publifhed in  the Memoirs of the French  Aca-
 demy of Sciences, for 1777, p. 426.
  Having filled  with Sulphuric Ether * a  fmall


  *I (hall afterwards give a definition, an.!  explain the
p: ope; lies of the liquor called Ether ;  I (hail therefore 
           OFCHEMISTRY.        57

  narrow  glafs veffel, A, (Plate  VII.  Fig.  17.),
  (landing upon its  ftalk P;  the  veffel,  which is
  from twelve to fifteen lines diameter,  is  covered
  by a wet bladder,  tied  round its neck with  fe-
  veral turns of ftrong thread ;  for greater fecuri-
  ty, a fecond bladder is fixed over the  firft.   The
  veflel fhould be filled in fuch a manner with  the
  ether, as not to leave the fmalleft portion of air
  between the liquor and the bladder.   It is now
  placed under the recipient BCD of an air-pump,
  of which the upper part B is fitted  with a  lea-
  thern collar, through which  paffes a  wire  EF
 having its point F very fharp ;  and in the fame'
 receiver there is placed the barometer  GH.  The
 whole being thus  dilpofed, let the  recipient be
 exhaufted, and then, by pufhing down  the wire
 EF, a hole is made in the bladder.  Immediate-
 ly the ether  begins to boil  with great violence,
 and is changed  into an elaftic  aeriform fluid]
 which fills the receiver.   If the quantity of ether
 be  fufficient  to leave  a few drops in  the phial,
 after   the evaporation  is finifhed,  the  elaftic
 fluid  produced will fuftain  the mercury in  the
 borometer attached to the air-pump,  at eight
 or ten inches  in winter,  and from  twenty  to

only prsmife here that it is  a very volatile, ard l.ir ly
inflammable liquor, having a  confider.'olv fmaller fjrecific
gravity than water,  or even  fpirjt 0f %v'ltic_____A
                     H 
5S
E  L E 11  E N T S
twenty -five in fummer*. To render this  experi-
ment more complete,  we may introduce a fmall
thermometer into  the phial A, containing the
ether  which will  be  found to defcend confide-
rably during the evaporation.
   The only effect  produced in this experiment,
is,  the taking  away the weight of the  atmo-
fphere, which, in  its ordinary  ftate, preffes  on
the furface of the  ether ; and the  effects refult-
ing from this removal, evidently prove, that, in
the  ordinary  temperature  of  the  earth, ether
would always  exift in an aeriform ftate, but for
the preffure of the atmofphere,  and  that  the
change of the ether from  the liquid to the aeri-
form ftate is accompanied by a confiderable  di-
minution  of temperature ;  becaufe,  during  the
evaporation, a part of the caloric, which was be-
fore in a free  ftate, or at leaft  in equilibriof in
the furrounding bodies, combines with the ether,
and caufes it to affume the aeriform ftate.
   The fame  experiment fucceeds with all eva-

  * It would have been more fatisfaclory if  the Anther
had f[veined the decrees of the therr.c mt'er at which
thefe heights of the mercury in the  barometer are pro-
duce d.-t.
  \ I fljould rav'.er fuppofe,  according to Mr I.avoifier's
o-vn principles, th;>* the evaporation 5". produced in con-
lequence of tW~ pquiKbr*!<m between the repulfive force
of the caloric contained in ihe  ether, and the refiftance
to expanfion exerted by the atmalpheric p.clLue being
reinuv.'d.—T. 
OF  CHEMISTRY.
59
 porable fluids, fuch as alkohol, water, and even
 mercury ; with this  difference, that the  atmo-
 fphere, formed in the receiver by alkohol only,
 fupports the attached barometer about  one inch
 in winter, and about four or five  inches in fum-
 mer ; that formed by water, in the fame  fituation,
 raifes the  mercury only a few  lines;  and that
 produced by quickfilver  raifes it but a  few frac-
 tions of aline.  There is, therefore, lefs fluid eva-
 porated from alkohol than from ether;  lefs from
 water than from alkohol; and ftill lefs from mer-
 cury than from either; confequently, there is lefs
 caloric employed, and lefs cold produced, which
 quadrates  exactly with the refults of thefe expe-
 riments.
   Another fpecies of experiment proves verv e-
 vidently, that the aeriform ftate is a modification
 of bodies dependent on the degree of tempera-
 ture, and on the preffure which thefe bodies un-
 dergo. In a Memoir read by Mr de la Place and
 myfelf to the Academy in 1777, Wuich has not
 been printed, we have fliewn, that, when ether is
 fubjected to a preuure equal to twenty-eip*ht inch-
 es of the barometer, or about the medium  pref-
 fure of the atmofphere, it boils at the temperature
 of about 1040, or 10.250  of the thermometer.
 Mr de Luc, who has made fimilar experiments
 with fpirit of wine, finds  it to  be:: at 182.750 ;
 And all theworld knows, that water boils  at 2120.
Now, boiling being only  the  evaporation of a 
60           ELEMENTS
liquid,  or  the moment of its  pafling from the
fluid to the aeriform ftate, it is  evident,  that, if
we keep ether continually at or above the tem-
perature of  106.250, and under the common
preiTure of the atmofphere, we  fhall have it  al-
ways  in an elaftic a riform ftate; and that the
Line thing will happen with alkohol  when  a-
bove \ 82."50, and with water when above 2120;
all which are. perfectly conformable to the fol-
lowing  experiment*.
   I filled a  laige veffel ABCD (Plate VII. Fig.
15.) with water, at no.75°,or  1130;  I fuppofe
the veffel tranfpa-rent, that  we  may fee what
takes  place in the experiment ;  and we can ea-
fily hold the hands in water at that temperature
without inconvenience.  Into this veffel I plunged
fome narrow-necked bottles F, G, filled wiili the
water, and turned up, fo as to reft on theirmouths
on  the bottom of the  veffel.   Having next put
fome ethir into a very fmall matrafs, with  its
neck, a be, twice bent as in the plate, I pluno-ed
this matrafs into the water, having its neck in-
ferted into the mouth of one of the  bottles  F.
Immediately on feeling the effects of the heat,
communicated to it by the water in the veffel
ABCD, the ether began to boil, and the caloric,
entering into combination  with it, changed it in-

  * VUe Memoirs  of  the French Academy, anno  1780,
p. 3 35.— A. 
OF CHEMISTRY.        6t
to an elaftic a'riform fluid, with which I rilled
feveral bottles fucceffively, F, G, Sec.
   This is not the place to enter upen the exami-
nation of the nature and properties of this a ri-
form fluid,  which  is  extremely  inflamuiai'e.
But, confining myfelf to the object at prelent in
view, without anticipating circumftan.ee,>, which
I am not to  fuppofe  the reader to know, I fhall
only  obferve, that the ether, from this experi-
ment, is aimoft only capable of exifting in  the
aeriform ftate in our ufual temperatures ; for, if
the weight of cur atmofphere was only equal to
between  20 and 24 inches of the barometer, in-
ftead of 28 inches, we mould never be able  to
obtain ether in the liquid fiat?,  at leaft in fum-
mer.  The  preparation  of ether would conse-
quently be impoflible upxi mountains of a mo-
derate degree of elevation, as  it would be con-
verted into gas immediately upon beini-  produ-
ced, unlefs  we employed recipients of  extraor-
dinary ftrength,  affiled by refrigeration and
ccrnprciTion.  And, laftly, the temperature cf the
blood being nearly  that  at  which  ether pe/fes
from the liquid to the aeriform ftate, it muft eva-
porate in the prima? vias ; and confequ-mtly it is
very probable that the medical properties of this
fluid depend chiefly  upon its mechanical effect.
  Thefe experiments fucceed better with nitrous
ether, became it evaporates in a lower tempera-
ture than fulphuric ether.   It  is more  diuicult 
62
ELEMENTS
 to obtain alkohol in the aeriform ftate ; becaufe,
 as it requires  a temperature of 182.75° t0  ra^e
 it to vapour, the water of the bath muft be al-
 moft bcib'sg ;  and it is impoflible to  plunge the
 hands into it at that temperature.
   It is evident, that,  if water were  ufed in the
 foregoing experiment, it would be changed in-
 to gas, when expofed  to a temperature tuperior
 to that at which it boils.  Although thoroughly
 convinced of this, Mr de la  Place and  myfelf
 judged it  neceffary to confirm it by the follow-
 ing direct experiment. We filled a glafs-jar, A,
 (Plate VII. Fig. 5.) with mercury, and placed
 it, with its mouth downwards, in a difh, B,  like-
 wife filled with mercury ;  and introduced about
 two drams of  water into the jar,  which rofe to
 the top of  the mercury at CD.  We then plun-
 ged the  whole apparatus into an iron boiler,
 EFGH, full of boiling fea-water, of the tempe-
 rature  of  223.25°, placed  upon  the furnace
 GH1K.   So foon as the water over the mercu-
 ry reached the temperature of 212°,  it began to
 boil; and, inftead of only filling the fmall fpace
 ACD, it was converted into an  aeriform fluid,
 which rilled the whole jar ;   the mercury even
 defcended below  the furface  of  that  in the difh
 B; and the jar muft have been overturned,  if it
 had not been very thick and heavy, and fixed  to
 the difh by means  of iron-wire.  Immediately
after withdrawing the  apparatus from  the  boil- 
          OF  CHEMIST RY        65

er, the vapour in the jar began to condenfe, and
the mercury rofe  to its former ftation;  but the
water returned again to the aeriform ftate in a
hv/ feconds after replacing the apparatus in the
boiler.
   We have thus a certain  number  of fubftan-
ces, which are  convertible  into elaftic aeriform
fluids, by degrees of temperature not much fu-
perior to that of our atmofphere.   We (hall af-
terwards find, that there are feveral others which
undergo the fame change in  fimilar circumftan-
ces, fuch as muriatic or marine acid,  ammoniac
or volatile alkali, the carbonic acid or fixed air,
the fulphurous acid,  &c.   All thefe are  perma-
nently elaftic in or about the mean temperature
of the atmofphere, and under its  common pref-
fure.
   All thefe facts,  which could be eafily multi-
plied, if neceffary, give  full right to affume, as a
general principle, that  almoft every body in na-
ture is fufceptible of three feveral ftates of exift-
ence, folid, liquid, and  aeriform ;  and that thefe
three ftates of exigence depend upon  the quan-
tity of caloric combined with the body.  Hence-
forwards  I fhall exprefs thefe elaftic aeriform
fluids  by the generic term gas :  and in each fj a-
cies of gas  I mall diftinguim between the c h>
ric, which in fome meafure ferves  the pcipofe of
afolvent, and the fubftance,  which, in coiiihina-
tion with the caloric, forms the bafe of the gas. 
64           E L  E M E N T  S
   To  thefe bafes of the  different gaffes, which
are hitherto but little known, we have been ob-
liged to aflign names.  Thefe fhall be enumera-
ted in Chap IV. of this work, when I have pre-
vioufly given an  account  of the phenomena  at-
tendant upon the heating and cooling of bodies,
and when I have eftablifhed preeife  ideas, con-
cerning the  compofition of our atmofphere.
   We have already fhewn, that the particles of
every fubftance in nature exift in a certain ftate
of equilibrium, between  that  attraction which
tends to  unite  and  keep the particles together,
and the  effects of the caloric  which  tends  to
feparate  them.   Hence,  caloric not only fur-
rounds the  particles of all bodies on every fide,
but  fills up every interval which  the  particles
of bodies leave between  each other.  We may
form an  idea of this, by  fuppofmg a veffel fil-
ed  with fmall  fpherical leaden bullets,  among
which a quantity of fine  fand  is poured ; this,
infinuating itfelf into the  intervals  between the
bullets, wit! fill, up every  v>ii.  The  balls,  in
thi-i companion, are, to ths fand which furrounds
them, exactly in the fame fituation  as the parti-
cles of bodies  are with refpect to  the  caloric ;
with this diffe?*ence only, that the balls  are fup-
pofed  to touch each  other, whereas the parti-
cles o" bodies are not in contact,  being retained
at  a fmall dhtance from each odier, by the ca-
loric. 
OF  CHEMISTRY
65
   If, inftead of fpherical balls we fubftitute folid
 bodies of a hexahedral, octohedral, or any other
 regular figure, the capacity  of the  intervals  be-
 tween them will be leftened, and  confequently
 will no longer contain the fame quantity of fand.
 The fame thing takes place with refpect to natu-
 ral bodies.   The intervals left between their par-
 ticles are not of equal capacity, but  vary in con-
 fequence of the different figures  and magnitude
 of their  particles, and  of  the diftance at which
 thefe particles are maintained, according to  the
 exifting  portion between their inherent attrac-
 tion, and the repulfive  force exerted upon them
 by the caloric.
   In this  manner we muft  underftand the fol-
 lowing expreffion, introduced by the Englifh phi-
 lofophers, who have given us" the firft precife ideas
 upon this fubjeft ; the capacity of bodies for con-
 taining the matter of heat.   As comparifons with
 fenfible  objects are of great ufe in affifting us to
 form diftinct notions of abftraft ideas, I fhall en-
 deavour to illuftrate this, by inftancing the phe-
nomena which take place between water and bo-
 dies which are wetted and penetrated by it, with
a few reflections.
  If equal pieces of different kinds of wood, fup-
pofe cubes of one foot each, be immcrfed  in
water, the fluid  gradually  infmuates  itfelf into
their pores,  and the pieces of wood  are  aug-
 mented both in  weight and  magnitude.  Each
                       I 
66
E  L E M E N T S
fpecies of wood will imbibe a different quantity
of water.  The lighter and more porous woods
will  admit a larger; the  compact  and  clofer
grained will admit a leffer quantity: for the
proportional quantities of water, imbibed by the
pieces,  will  depend upon the nature of the con-
ftituent particles  of the  wood,  and  upon the
greater or leffer affinity fubfifting between them
and water.   Very  refinous  wood, for inftance,
though it may be at the  fame time very porous,
will admit but little water.  We may,  therefore,
fay,  that different kinds of wood poffefs differ-
ent capacities for receiving water :  and we may
even determine, by means of the augmentation
of their weights,  what quantity of water they
have actually abforbed : but, as we are ignorant
how much water they contained previous to im-
merfion, we  cannot determine the abfolute quan-
tity  they  contain  after being taken out  of the
water.
  The  fame circumftances  undoubtedly  take
place with bodies which are immerfed in caloric;
taking into  confuhration, however, lhat water
is .an incomprehi" ale.fluid^ whereas caloric is, on
the contrary, endowed with  very  great elaftici-
ty ;  or, in other words,  the particles  of caloric
have a great tendency  to  feparate from  each
other,  when forced by any  other power to ad-
proach.  This difference  muft of neceflity occa- 
          OF  CHEMISTRY.        67

fion very confiderable diverfities in the  rciuhs
of experiments made upon thefe two  fubftan-
ces.
  Having eftablifhed thefe clear and fimple pro-
pofitions, it will be very cafy to explain the ideas
which ought to be affixed to  the following ex-
preflions, which are by no means fynonymous,
but poffefs each a ftrict affd determinate meaning,
as in the following definitions:   •
  Free caloric is  that  which is not combined
in any manner with any  other body.  But, as
we  live in a  fyftem to the matter of which calo-
ric  has  a very ftrong adhefion, we are  never
able.to  obtain it in  the ftate  of abfolute free-
dom.
  Combined caloric is that  which is  v.xed  in bo-
dies, by affinity or elective attraction,  fo as to
form part of the  fubftance of trie  body, even
part of its folidity.
  By the expreffion, fpecific  caloric of bodies,
we  underftand the refpective quantities of calo-
ric  requifite for raifing a  number of bodies of
the  fame weight  to  an equal degree of tempe-
rature.   This proportional quanti y of caloric
depends on  the diftance  between the conftitu-
ent  particles of bodies, and their greater or leffer
degrees of cohefion ; and  this diftanee, or rather
the  fpace or  void refulting from it, is, as  1 have
already obferved, called the capacity "of bodies for
containing caloric. 
68          ELEMENTS

  Heat, confidered as a  fenfation, or, in other
words,  fenfible heat, is only the effect produ-
ced upon our fentient organs, by the motion or
paffage  of  caloric, difengaged from the  fur-
rounding  bodies.   In general, we receive im-
preifuns only in confequence of motion : and it
might be  eaablithed  as an axiom, "That with-
out MOTION, THERE IS NO SENSATION.  Thio
general  principle applies  very accurately to the
fenfations of heat and cold.  When we touch a
cold body, the caloric, which always  tends to
become in epuilibrio in all bodies, paffes from
our hand into the  body we touch, winch gives
us  the  feeling or fenfation  of cold.  The direct
contrary happens,  when we touch a warm bo-
dy:  the caloric, then, in pafling  from the body
into our hand, produces  the  fenfation  of heat.
If the hand and the body touched  be of the fame
temperature, or very nearly fo, we receive no im-
preftion, either of heat or cold; becaufe there is
no  motion  or  paffage of caloric ; and thus no
fenfation can take place, without fome correfpon-
dent motion to occafion it.
   When  the thermometer rifes,  it fhows, that
free caloric is entering into the  furrounding
bodies. The thermometer,  which is one of thefe,
receives its fhare in proportion to its  mafs,  and
to  the capacity which it poffeffes  for containing
caloric.  The  change,  therefore, which takes
place upon the thermometer,  only announces a 
        OF   CHEMISTRY.        69

change of place of the caloric in thofe bodies, of
which  the thermometer forms one parr.  It only
indicates the portion of caloric received, without
being a meafure of the whole  quantity difenga-
ged, diiplaced, or abforbad.
  The moil fimple and moft exact method for
determining this latter point, is  that  defcribed
by Mr de  la Place, in the Memoirs of the Aca-
demy, for the  year 1780, p. 364:  a fummary
explanation of which will be found towards the
conclufion of this work.  This method confifts
in placing a body, or a  combination of bodies,
from which caloric is difengaging, in the middle
of a hollow fphere of ice : and  the quantity of
ice melted becomes an exact relative meafure of
the quantity of caloric difengaged.  It is poffible,
by means  of the  apparatus  which  we have got
conftructed upon  this plan, to determine,  not as
has been pretended, the capacity of bodies  for
containing heat, but the ratio  of the increafe or
diminution  of capacity  produced  by determi-
nate  degrees of temperature.   It is  eafy, with
the fame apparatus, by varioufly combined  ex-
periments, to  determine the relative  quantities
of caloric  neceffary for converting folid fubftan-
ces into liquids, and liquids  into elaftic aeriform
fluids ; and vice  verfa,  what quantity of calo-
ric efcapes from  elaftic vapours in  chancrinp- to
liquids, and what quantity  efcapes from  liquids
during their converfion into folids. Perhaps, when 
70
E  L  E  M E N T S
 experiments fnall have been made with fufficient
 accuracy, we may one day be able to determine
 the pi oportional quantities of caloric neceffary for
 producing the feveral  fpecies  of  gaffes.  I fhall
 hjreatter, in a feparate chapter, give an account
 01 the principal  remits of fuJi experiments  as
 have been made upon this head.
   It remains, before finifmng  this article, to fay
 a few words concerning  the caufe of the efafti-
 city of gaffes, and  of liquids in the ftate of  va-
 pour.   It is by  no means difficult  to perceive
 that this elafticity depends upon that of  caloric,
 which feems to be the  moft eminently elaftic
 body in nature.   Nothing is more readily con-
 ceivable, than that one body  fhould become e-
 laftic, by  entering into combination  with  ano-
 ther body  poffeffed of that  quality.   We  muft
 allow that this is only an explanation of elafti-
 city, by an affumption of elafticity. We thus on-
 ly remove  the difficulty one ftep farther ;   and
 the reafon  for caloric being elaftic, ftill remains
 unexplained.  1 Iafticity in the abftract is mere-
 ly a  fuppofable qualirv inherent to the particles
of bodies, by virtue of which  they recede  from
each other when forced together.   This tenden-
cy in the  particles  of caloric  to feparate, takes
 place even at confiderable diftances.   We fhall
be fatisfied of this, when we  confider, that  air
is capable  of undergoing great  compreffion;
which  fuppofes  that its particles  were previouf- 
OF  CHEMISTRY.
7i
 ly  at a confiderable diftance from each other;
 for the power of approaching toget' er certain-
 ly fuppofes a previous diftance, at  leaft equal  to
 the degree of approximation.  Confequently, thofe
 particles of the air, which  are already confide-
 rably diftant from each  other, tend to feparate
 ftill  farther.  If we produce  Boyle's  vacuum
 in a large receiver of an air-pump, the laft por-
 tion of air which remains, extends itfelf uniform-
 ly through the whole  capacity of the veffel,
 however  large,  filling it completely,  and preff-
 ing every where againft its  fides.   We  cannot
 explain this fact, without fuppofing that the par-
 ticles make an effort to  feparate themfelves on
 every  fide : and we are quite ignorant at what
 diftance, or in what degree of  rarefaction,  this
 effort ceafes to act.
  In the  above experiments, a true repulficn
 takes  place  between  the particles of  elaftic
 fluids.   At leaft, circumftanccs occur exactly a>s
 if fuch a repuliion actually exifted :  and we have
 a right to conclude, that the  particles of caloric
 mutually repel each  other.   When we are once
 permitted to fuppofe this repelling force,   the
theory of the formation  of gaffes," or aeriform
fluids,  becomes  perfectly fimple:  though we
muft, at  the fame  time, allow, that it  is  ex-
tremely difficult  to  form  an accurate concep-
tion how  this repulfive force acts upon very mi- 
72
ELEMENTS
 nute particles placed at great diftances from each
 other.
   It is, perhaps, more natural  to fuppofe, that
 the particles of caloric have a ftronger  mutual
 attraction  than thofe  of  any  other fubftance;
 and that thefe latter particles are torn afunder
 in confequence  of this fuperior attraction of the
 particles of caloric,  which forces them between
 the particles  of other bodies, that they may  be
 able to  reunite  with each  other.  We may  ob-
 ferve fomething analogous to this idea in the phe-
 nomena  which occur when a  dry fponge is dipt
 in water. This fponge  fwells; ,its particles fepa-
 rate from each  other; and a!l its intervals are
 filled by the water.  It is evident, that the fponge,
 in the  act of fwelling, has acquired  a  greater
 capacity*  for containing water than it« had  when

  * This afTertion does  not feem well founded:—That, in
 the a& of fwelling, the fponge  receives pure  water than it
held when dry,  ij v^ry ; vident ; and that, in conloouer.ee of
its fibres bring ftretched, more room is L'ft"between them, is
likewife true; But if, by capacity for  rnceivin~ water,  we
 are to undjrfland tha; quality inherent i.i the fponge  for im-
bibing wat-;, in confluence of the  difpofition and peculiar
 ftrudture of its parts, this remhrio the fame v/lien perfitly
dry as when tiUed completely with nioiflure ; or, ifwe cc,-.-
fider its c-ipacity to indicate h~  difpofition for receiv.'rp ad-
 ditional wa:?r, this rnuft be greacrft wher< perfectly drv, and
 mult diminish in prcporiLa  as the water L received  into its
 interiiices.—T. 
          OF  CHEMISTRY.        73

 dry.  But we  cannot certainly  maintain,, that
 the introduction of water between the particles
 of  the fponge  has endowed them with a repul-
 five power,  which tends  to  feparate them from
 each other:  on the contrary, the  whole phe-
 nomena are  produced by means of attractive
 powers :  Thefe are, the  gravity of the water,
 and the power  winch it  exerts on every fide,
 in common  with all other fluids  ; the force of
 attraction, which takes place between the parti-
 cles  of  water,  caufmg  them to  unite  toge-
 ther ; the  mutual attraction of the particles of
 the  fponge for each other ;  and, the recipro-
 cal attraction which exifts between the particles
 of the fponge and thofe of the water.   It  is  ea-
 fy to- underftand,  that the  explanation  of this
 fact depends upon properly appreciating the m-
 tenfity of, and  connection between,  thefe feve-
 ral powers.   It is probable, therefore, that the
 feparation  of the particles of bodies, occafonci
 by caloric, depends in a fimilar  manner upon a
 certain combination of diihirent attractive :.ow-
 er-i, which, in conformity with the imperfection
 of our knowledge, we endeavour  to exprefs  by
faying, that caloric  communicates a power of
repulfion to the particles of bodies.
K 
74
ELEMENTS
              C II  A  T.   II.

General Views concerning the Formation and Com-   ,
           pofiiion of our /lln; f^bere.


     THESE views which I have taken of the for-
      mation  of elaftic  aeriform fluids or  gaf-
fes, throw  great light upon the original forma-
tion of the  atrnofpheres of the planets,  and  par-
ticularly of that of cur earth.  We readily con-
ceive, that  it muft neceffarily confift of a mix-
ture of the following fubftances :  Of all bodies
that are fufceptible  of evaporation, or, more
ftrictly  fpeaking, which are capable of retain-
ing the ftate of aeriform elafticity \n the tem-
perature of our atmofphere, and under a pref-
fure equal  to that of a column of twenty-eight
inches of quickfilver in the barometer ; and, of
all  fubftances,   whether liquid cr fo'U,  which
are capable of bJiig diifolved in this mixture of
different gaffes.
   To f.x our Lh:as move clearly refpecting this
fubject, which  has  not been hitherto fufficient-
ly confidered,  let us, for a  moment,  conceive
what change "would  take  place in  the varies
* 
        OF  CHEMISTRY.        75

fubftances which compofe our earth, if its tem-
perature were fuddenly altered.   If, for inftance,
we were fuddenly tranfported  to the region of
the planet Mercury, where probably the  com-
mon  temperature is much fuperior to  that of
boiling water ;  the water of cur world, and all
the other fluids which are fufceptible of the gaf-
feous ftate, at a  temperature near  to  that of
boiling  water, even quickfilver  itfelf, would be-
come rarefied :  and  all thefe fubftances, being
changed into permanently aeriform fluids or gaf-
fes, would become part of  the new atmofphere.
Thefe new fpecies of airs or gaffes would  mix
with thofe already exifting,  and certain recipro-
cal decompofitions and new combinations would
take place, until fu:h time  as all the elective  at-
tractions or  affinities fubfifting  among all thefe
new and old  gaffeous  fubftances had operated
fully ;  after  which, the elementary  principles
compofing thefe gaffes, being faturated, would
remain  at  reft.
  We muft attend  to this, however, that, even
in  the  above hypothetical fttuation,  certain
bounds  would occur to the evaporation of thefe
fubftances, produced  by means of that  very-
evaporation itfelf.  For as,  in proportion to the
increafe of elaftic  fluids, the preffure  of the at-
mofphere would  be augmented—as every de-
gree of  preffure tend,,  in fome meafure, to pre-
vent  evapcration—and as  even  the  moll eva- 
76         ELEMENTS

porable fluids can refift the operation of a very
high  temperature  without evaporating, if pre-
vented by a proportionally ftronger compreflion,
v/ater and ajd other liquids being able to fuftain
a red heat in Papin's digefter ;  v. e muft admit,
that the  new atmofphere would at laft acquire
fuch a degree of weight,  that the water  which
had not hitherto evaporated, would ceafe to boil,
and, of confequence, would remain lie end. Hence,
even upon this fuppofition, as in all others of the
fame nature, the increafing gravity of the atmo-
fphere would find certain limits which  it could
not exceed.
   We might extend thefe reflections  greatly
farther,  and examine  what  change would  be
produced in fuch fituations  upon  ftones,  falts,
and the greater part of  the  fufible  fubftances
which  compofe the mafs of our earth.   Thefe
would  be foftened, fufed, and changed into  li-
quids,  2;c.   But  thefe {peculations carry me
from  my object,  to which I  ha ft en  to re-
turn.
   By  a  contrary  fuppofition,  to  the one we
have been forming, if the earth  were fuddenly
trtmlported into a  very cold region,  the water,
which at preent compofes our feas, rivers, and
fprings, and  probably  the greater number  of
the fluids we are  acquainted with,  would  be
converted into folid mountains  and hard rocks,
at firft diaphanous and  homogeneous, like rock 
OF  CHEMISTRf.
77
 cryftal, but  which, in time,  becoming mixed
 with  foreign  and   heterogeneous   fubftances,
 would become crake ftones of  various  colours.
 In this cafe, the  air, or,  at  leaft, fome of the
 aeriform fluids  which  now compofe the  mafs
 of our  atmofphere,  would doubtlefs  lofe  their
 elafticity,  for want  cf  a  fuillcient  temperature
 to retain them in that ftate.  They would re-
 turn to the liquid ftate of exiftence* :  and new-
 liquids would be formed, of whofe properties we
 cannot at prefent, form the moft diftant idea.
   Thefe two  oppofite  fuppcfitions give a  di-
 ftinct proof of the  following corollaries :  That
folidity,  liquidity,  and aeriform  elaflicity, are on-
 ly three different  ftates of exiftence  of the  fame
 matter, or three particular  modifications which
 almoft all fubftances are fufceptihle  of autumn 7
 fucceffively, and which folely depend on the de-
 gree of temperature to which they are expofed;
 or, in other  words,  upon the  quantity  of calo-
 ric with which they  are penetratedf;  that  it  is

  * Even this fjppofition would have  its bo'i^'s from its
 own nature.  Tne diminution of preiTirc, produced by '.he
 decreafe in the vo!u wt,  and  confequent gravity, cf the rr-
 rr.cipl.~re, would enable  caloric to keep nr.ny lVuf:r.r,c,c; in
 the vaporous Ibte, at a much lower degree of temperature
 than is frt Lr that purpefe, under the prefent preffure of c-r
 atmctj here —T.
   \ The degrve cf prcffjre w'rch they und?r?n mu't be ta-
 ken in:o account.—T. 
78
ELEMENTS
extremely probable that air is a mud naturally c-x-
ifting in a ftate of vapour; or, as we may better
exprefs it, that our atmofphere is a compound of
all the fluids which are fufceptible  of  the vapo-
rous or permanently elaftic ftate, in  the ufual
temperature, and under the common  preffure ;
that it is  not impoffible we may  difcover, in
our  atmofphere,  certain  fubftances  naturally
very compact, even  metals  themfelves  ; as   a
metallic fubftance, for  inftance,  only  a little
more volatile than mercury, might exift in  that
fituation.
  Among  the fluids  wdth which  we are ac-
quainted,  fome,  as water and alkohol, are fuf-
ceptible of mixing with each other in all pro-
portions;  whereas others, as quickfilver, water,
and oil, can only form a momentary union, and,
after  being mixed together, feparate and  ar-
range themfelves according to their fpecific gra-
vities.  The  fame ought to, or at leaft may,
take place in the atmofphere.  It is poffible, and
even  extremely  probable,  that,  both   at the
firft creation, and every day,  gaffes are formed,
which are  difficultly  mifcible with atmofpheric
air, and are continually feparating from  it.   If
thefe gaffes be fpecifically lighter than the gene-
ral atmofpheric mafs, they muft, of courfe, gather
in the higher regions, and form ftrata that float
upon the common air.  The phenomena which 
         OF  CHEMISTRY.       79

accompany igneous meteors, induce  me to be-
lieve, that there exifts, in the upper parts of our
atmofphere, a ftratum of inflammable fluid,  in
contact with thofe ftrata of air in which the phe-
nomena of the aurora borealis and other fiery ap-
pearances are produced.—I  mean hereafter  to
purfue this fubject in a feparate treatife. 
c>0
ELEMENTS
              CHAP.  111.

Analyfis of Atmofpheric Air$ and its Divifon into
   two Elaftic  Fluids ;  the one fit for Rcfpiraliui ;
   the. other incapable of being refpired.


 || f-ROIvi" what has been premifed, it appears,
JL   that our atmofphere is compofed of a mix-
ture of every fubftance capable cf retaining the
gafieous or aeriform ftate in the common tempe-
ratures, and under  the ufual degrees of preffure
which it  experiences.   Thefe fluids conftitute a
mafs, in fome  meafure homogeneous, extending
from the furface of  the  earth  to  the  greateft
height hitherto  attained,  of which the denfity
continut.ily decreafes in the inverfe  ratio of the
fuperincumbent  weight.   But, as I have before
obferved, it is  poffible that this fir ft ftratum may
be furmounted by feveral others confifting of dif-
ferent fluid:.
   Our bufmefs, in this place, is to endeavour
to determine  by  experiments,  the nature  of
the elaftic fluid"  which compofe the  inferior frn-
tum of air which we inhabit.   Modern chemif-
try has made great  advances in  this  refcarca :
and it will appear, by the  following details, that
the analyfis of atmofpherical air ha:, been more 
         OF  CHEMISTRY.       81

rigoroufly  determined than that of any other
fubftance of the clafs.
   Chemiftry affords two general methods of de-
termining the  conftituent principles of bodies,
the method of analyfis, and that of fynthefis.
When,  for inftance, by combining water with
alkohol, we form the fpecies of liquor called, in
commercial language, brandy or fpirit  of wine,
we certainly have  a right  to  conclude,  that
brandy, orfpirit of wine, is compofed of alkohol
combined with  water.  We can  procure  the
fame  refult by  the  analytical  method: and  in
general  it ought to be confidered as a  principle
in chemical fcience, never to reft fatisfied with-
out both thefe fpecies  of proofs.  We  have this
advantage in the analyfis of atmofpherical air ;
being able both to decompound it, and to form
it anew in the moft fatisfactory manner. I fhall,
however, at prefent  confine  myfelf to  recount
fuch experiments as  are moft conclufive upon
this head :  and  I  may confider  moft  of thefe as
my own, having  either firft invented them,  or
having repeated thofe of others, intended for
analyfing atmofpherical  air,  in perfectly new
points of view.
  I took a  matrafs of about 36 cubical inches
capacity, having a long neck of fix or feven lines
internal  diameter, and having bent the  neck, as
in Plate  IV. Fig. 2. BCDE,  to  allow of its  be-
                      L 
8fl
ELEMENTS
ing placed in the furnace MMNN, in fuch a
manner that the extremity of its neck E might
be inferted under a beli-glafs  F G, placed in a
trough of quickfilver RRSS;  I introduced four
ounces of pure mercury into the matrafs, and
by means of a fyphon, exhaufted the air in the re-
ceiver FG, fo as to  raife the quickfilver to LL ;
 and I carefully marked the height at which it
flood, by parting on a flip of paper.  Having ac-
curately noted  the  height  of  the  thermometer
and  barometer, I lighted a fire in the furnace
 MMNN, which I  kept  up almoft continually
 during twelve days, fo as to keep the quickfilver
 always very near its boiling point.  Nothing re-
 mark able took "place  during the firft day.  The
 mercury, though not  boiling,  was continually e-
 vaporating,  and  covered  the  interior furface of
 the veffel with  fmall drops, which gradually aug-
 menting-to  a  fufficient fze,  fell back into the
 mafs at the bottom  of the veffel.   On ihe fecond
 day, fmall red  particles began to appear on the
 furface of the mercury. Thefe, during the four or
 five following  days,  gradually increafed in fize
 and number ; after which they ceafed to increafe
 in either refpect.  At the end of twelve days, fee-
 ing that the calclua.icii of the mercury did  not
 at all increafe, I extinguifhed  the fire, and allow-
 ed the veffels  to cccl.  The bull: of air in the
 body and neck of  the  maarafs, and in  the bell- 
          OF  C HE nil ST R Y         83

 glafs, reduced to a medium of 28  inches of the
 barometer and 54.5° of the thermometer, at the
 commencement of the experiment was about 50
 cubical  inches.   At  the end of the experiment,
 the remaining air, reduced to the  fame medium
 preffure and temperature, was only between  42
 and 43 cubical inches ; confequently it had loft
 about  4. of its  bulk.  Afterwards, having col-
 lected all the  red  particles,  formed during the
 experiment, from the running mercury in which
 they  floated,  I  found thefe  to amount  to  45
 grains.
   I was obliged to repeat this experiment  feve-
 ral times;  as it  is difficult, in one experiment,
 both  to preferve  the whole air upon which we
 operate, and to collect the whole of the red  par-
 ticles, or calx of mercury, which is formed du-
 ring  the  calcination.   It  will often happen  in
 the fequel, that I fhall in this manner, give  in
 one detail the refults  of two or  three experi-
 ments of the fame nature.
   The air which  remained  after the calcination
 of the mercury in this experiment, and which
was reduced  to  4 of its former  bulk, was no
longer fit  either  for refpiration or  for  combuf-
tion.  Animals being introduced into it were fuf-
focated in a few feconds:  and when a taper  was
plunged into it, it was  extugu.med, as if it  had
been immerfed in water. 
84
ELEMENTS
   In the next place, I took the 45 grains of red
matter formed during  this experiment, which I
put into a fmall  glafs  retort,  having a  proper
apparatus for receiving fuch liquid or  gaffeous
product, as might be extracted.  Having  applied
a fire to the retort  in the furnace, I obferved
that,  in  proportion  as the red matter  became
heated, the  intenfity of  its colour  augmented.
When the retort  was  almoft  red  hot,  the red
matter began gradually to decreafe in bulk ; and
in a few  minutes after, it difappeared altogether.
At the fame time 41 a grains of running mercury
were collected in the recipient: and 7 or  8 cu-
bical inches of elaftic  fluid, greatly  more  capa-
ble of fupporting  both refpiration and  combuf-
tion than atmofpherical  air, were  collected in
the bell-glafs.
  A  part of this air being put into a glafs tube
of about an inch diameter, fhewed the following
properties :   A taper  burned in it with a  daz-
zling fplendor:  and  charcoal, inftead of con-
fuming quietly as it does in common air,  burnt
with a flame, attended with a decrepitating  noife,
like phofphorus ;  and threw  out  fuch a bril-
liant light that the eyes could hardly  endure it.
This fpecies of air was difcovered  almoft  at the
fame time  by  Dr Prieftley,  Mr Scheele, and
myfelf.  Dr Prieftley gave it  the  name of de-
phlogifticated air.  Mr Scheele called  it  empyreal
air.  At firft I named it highly refpirable air, to 
OF  CHEMISTRY.
«5
which has  fince been  fubftituted  the  term of
•vital air.   We fhall prefently fee what we ought
to think of thefe denominations.
   In reflecting upon the circumftances of this
experiment, we  readily perceive that,  the mer-
cury, during its  calcination, abforbs the  falu-
brious and refpirable part of the air, or, to fpeak
more ftricfly, the bafe of this refpirable part;
that the remaining air is  a  fpecies of mephitis,
incapable  of fupporting  combuftion or refpira-
tion ; and, confequently,  that atmofpheric air is
compofed of two elaftic fluids,  of different and
oppofite qualities.   As a proof of this important
truth, if we  recombine thefe two elaftic fluids,
which wre have feparately obtained in the above
experiment, viz. the 42 cubical inches of mephi-
tis, with the 8 cubical inches of highly refpirable
air, we reproduce an air precifely fimilar to that
of the atmofphere, and poffeffmg neatly the fame
power of fupporting combuftion and refpiration,
and of contributing to the calcination of metals.
   Although this experiment furnifhes us with
a very fimple means of obtaining the  two prin-
cipal  elaftic  fluids  which  compofe  our  atmo-
fphere, feparate from each other ; yet it does not
give us  an exact idea of the  proportion in which
thefe  two enter  into its compofition.   For the
attraction  of mercury to the refpirable part of
the air, or rather to its bafe,  is not  fufficiently
ftrong to  overcome all the  circumftances which 
-86           ELEMENTS

oppofe this union.   Thefe obftacles are the mu-
tual  adhefion of the two conftituent  parts  of
the atmofphere for each other, and the  elective
attraction which unites the bafe of vital air with
caloric. In confequence of thefe,  when the cal-
cination ends, or is at leaft carried as far as is
poffible in a determinate quantity of atmofphe-
ric air, there  ftill remains a portion of refpirable
air united to the mephitis, which the mercury
cannot  feparate.   I fhall afterwards fhew, that
at leaft in  our climate, the atmofpheric  air  is
compofed  of refpirable  and mephitic  airs,  in
the proportion of 27 and 73 ;  and I fhall then
difcufs the caufes of the uncertainty which ftill
exifts with refpect to the exactnefs of that pro-
portion.
   Since, during the calcination of mercury,  air
is decompofed,  and the  bafe of its  refpirable
part  is fixed  and combined with the mercury,
it follows,  from the principles already eftablifh-
ed, that  caloric and  light muft be difengaged
during the  procefs.  But the  two following
caufes prevent us from  being fenfible  of this
taking place  ; as the  calcination  lafts during fe-
veral days, the difengagement of caloric and
light, fpread  out in a confiderable fpace of time,
becomes  extremely  fmall for  each particular
moment of  the time, fo as not  to be percep-
tible ; and,  the operation being  carried on  by
means of fire in a furnace,  the heat  produced 
OF CHEMISTRY.       87
by the calcination  itfelf, becomes confounded
with  that   proceeding  from  the furnace.  I
might add, that the  refpirable part of the air, or
rather its  bafe,  in entering into  combination  -\
with  the  mercury, does not part  with  all the
caloric  which  it contained, but  flill retains a
part of it  in the new  compound.  But the dif-
cuflion  of this point,  and its proofs from ex-
periment, do not belong to this part of our fub-
jea.
   It  is, however, eafy  to render this  difengage-
ment of caloric and light evident  to  the fenfes,
by caufing the  decompofition of air  to  take
place in a more rapid  manner ; and for this pur-
pofe, iron is excellently adapted, as it  poffeffes
a much ftronger affinity for the bafe  of refpira-
ble air than mercury.  The following elegant ex-
periment  of Mr Ingenhouz, upon  the  combuf-
tion  of iron, is well  known.   Take a piece  of
fine  iroij. wire,  twifted into  a fpiral, BC,  Plate
 IV. Fig.  17. fix one  of its extremities B into
 the cork  A, adapted to the neck  of the bottle
 DEFG, and fix  to the other extremity of the
 wire C, a  fmall morfel of tinder.  Matters be-
 ing  thus  prepared, fill the bottle DEFG  with
 air deprived of its  mephitic part.   Then  light
 the  tinder, and  introduce it quickly,  with the
 wire upon which  it  i; fixed, into the  bottle
 which you flop up with the cork A,  as is fnowii
 in the figure 17.  Plate  IV.   The inftant the 
 88           E L E  M E  N T S

 lighted tinder comes  into contact with the -vi-
 tal air, it begins to burn with great intenfity ;
 and  communicating  the inflammation  to  the
 iron-wire, it likewife takes fire and burns rapidly,
 throwing out brilliant fparks. Thefe fall to the
 bottom of the veffel in rounded globules, which
 become  black in cooling, but retain  a degree
 of metallic  fplendor.   The  iron thus burnt is
 more brittle  even  than glafs ; is eafily reduced
 into powder ;  and is ftill attractible by the mag-
 net, though not fo powerfully as it was before
 combuftion.  As Mr. Ingenhouz has neither ex-
 amined  the change  produced on  the iron,  nor
 upon the air by this operation, I have repeated
 the experiment under  different circumftances,
 in an apparatus adapted to anfwer my  particu-
 lar views, as follows.
   Having filled a bell-glafs A, Plate IV. Fig. 3.
 of about  fix pints meafure, with pure air, or the
 highly refpirable part of air, I tranfported this
jar, by means of a very flat veffel, into  a quick-
 filver bath,  in the bafon BC, taking care to ren-
 der the furface of the mercury perfectly dry, both
 within and without  the jar, with blotting paper.
 I then provided  a fmall cup of china-ware  D,
 very flat  and open, in which I placed fome fmall
 pieces of iron  turned fpirally, and arranged  in
 fuch a way  as feemed  moft  favourable for the
 combuftion  being communicated to every part.
 To the end  of one of thefe pieces of iron  was 
        OF   CHEMISTRY.        89

fixed a fmall  morfel of tinder,  to  which was
added  about the fixteenth part of a  grain of
phofphorus: and by  railing  the   bell-glafs  a
little,  the china cup, with  its contents,  were
intredueed into the pure air.   I  know  that,  by
this means, fome  common  air  muft mix with
the pure  air in the glafs :  but  this, when it is
done  dextroufly, is fo very trifling, as not to
injure the fuccefs of the experiment.  This be-
ing done, a part of the air was fucked out from
the bell-glafs, by means of the fyphon GHI, fo
as to raife the mercury within the glafs to EF :
and, to prevent the mercury from  getting into
the fyphon, a fmall piece  of paper  was twifted
round  its extremity.  In  fucking out the air, if
the motion of the lungs only be ufed,  we can-
not make the mercury rife above an inch or an
inch and a half.  But,  by properly ufing the
mufcles of the mouth, we can, without difficul-
ty, caufe it to rife fix or feven inches.
   I next took an iron wire, MN, Plate IV.
Fig. 15.  properly bent for  the purpofe; and,
making it red  hot in the  fire, paffed it through
the mercury  into the  receiver,  and brought it
in contact with the fmall piece of phofphorus
attached to the tinder.   The phofphorus  in-
ftantly took fire,-which communicated to the
tinder,  and from that to the iron.   When the
ph  es  have been properly arranged, the whole
iron burns,  even to the laft particle,  throwing
                    Id 
50
ELEMENTS
out a white brilliant light, fimilar to that of Chi-
nefe fireworks.  The great heat produced by this
combuftion  melts the iron into round globules
of different  fizes,  moft of which fall  into the
China cup :  but fome are thrown out of it, and
fwim on the furface of the  mercury.   At the
beginning of the combuftion, there is a flight
augmentation in the volume  of  the air in the
bell-glafs, from  the dilatation  caufed by the
heat.    But  prefently afterwards, a rapid dimi-
nution of the air takes place, and the  mercu-
ry rifes  in the glafs ;  infomuch that, when the
quantity  of  iron is  fufficient, and the air ope-
rated upon is very pure,  almoft  the whole  air
employed Is  abforbed.
   It is proper to remark in this place, that, un-
lefs in making experiments for  the purpofe of
difcovery, it  is better to be contented with burn-
ing a moderate quantity of  iron: for, when
this experiment is pufhed too far,  fo as to ab-
forb  much of the air,  the cup D, which floats
uaon the quickfilver, approaches  too near the
bottom  of the  bell-glafs: and  the great heat
produced, which  is followed by a very fudden
cooling,  occafioned by the contact of the cold
mercury, is  apt to break the glafs : in which
cafe, the fudden fall of the  column of mercury,
which  happens the moment the  leaft  flaw is
produced in the glafs, caufes fuch a wave, as
throws a great part of the quickfilver from the 
           OF  CHEMISTRY.        91

 bafon.  To avoid this inconvenience, and to en-
 fure fuccefs to the experiment, one dram and a
 half of iron is fufficient to burn in a bell-glafs,
 which holds about eight pints of air.  The glafs
 ought likewife to be ftrong, that it  may be  able
 to bear  the  weight of the column of mercury
 which it has to fupport.
   By  this experiment, it is not poffible to de-
 termine, at one time, both the additional  weight
 acquired by the iron, and the changes which
 have taken place in the air.  If it is wifhed to af-
 certain what additional weight has been gained
 by the iron, and the proportion  between  that
 and  the  air abforbed,  we  muft carefully mark
 upon the bell-glafs, with a  diamond, the height
 of the  mercury, both before  and after  the  ex-
 periment.  After this, the fyphon, GH, PI. IV.
 Fig. 3. guarded, as before, with a bit of paper,
 to prevent its filling with mercury, is to be  in-
 troduced under the bell-glafs,  having the thumb
 placed upon the extremity, G, of the fyphon, to
 regulate  the paffage of the  air :  and by   this
 means  the  air is gradually admitted, fo as to let
 the mercury f 11  to  its level.   This being done,
 the bell-glafs is  to  be carefully removed ;  the
 globules  of melted  iron contained in the cup,
and thofe which have been fcatterei a! out,  and
fwim upon the  mercury,  are to be accurately
collected; and the whole is to be weighed.  The
iron  will be found  in that  ftate  called martial 
ELEMENTS
cthiops by the old chemifts, poffefhng a degree cf
metallic brilliancy, very friable, and readily redu-
cible into powder, under the hammer, or with a
peftleand mortar.  If the experiment has  fuc-
ceeded well, from ioo grains of iron will be  ob-
tained 135 or  136 grains of ethiops, which is an
augmentadon of 35 per cent.
   If all the attention has been paid to this ex-
periment which it deferves, the air will be found
dim! 11 (bed in weight, exactly equal to what the
iron has gained.   Having therefore burnt  100
grains of iron, which has acquired an addition-
al weight  of  35 grains, the diminution  of air
v/ill be  found exactly 70 cubical  inches :  and
it will be fnewn, in the fequel,  that the  weight
of vital  air is very near half a grain  fcr each
cubical  inch;  fo that, in effect,  the augmenta-
tion of weight in the  one exactly coincides with
the lofs of it in the other.
   I fhall  obferve here, once for all, that, in e-
very experiment of this  kind, the preffure and
.temperature of  the  air,  both before  and after
the  experiment,  muft be  reduced  by calcula-
tion, to a common ftandard of 54.5 ° of the ther-
mometer, and 28 inches of  the barometer.  To-
wards the  end of this work, the manner of per-
forming this  v_ry neceffary  reduction  will be
found accurately detailed.
   If it  be required to examine the nature of the
 air  which  remains  after this experiment,  we
1 
         OF  CHEMISTRY.        93

muft  operate  in a fomewhat  different manner.
After the combuftion is finifhed, and  the veffels
have cooled, we  firft take cut the cup, and the
burnt iron, by introducing tie hand through the
quickfilver, under the bell-glafs. We next intro-
duce fome foiution of potafh, or cauftic alkali, or
of the fulphuret of potafh, or fuch other fubftan-
ces as are judged proper for examining their ac-
tion upon the refiduum of air.   I fhall, in the fe-
quel, give an account of thefe  methods of analy-
fing air, when I  have  explained the nature of
thefe different fubftances, which are only here in
a manner incidentally mentioned.  After this exa-
mination, fo much  water  muft  be let into the
glafs as will difplace  the quickfilver ;  and then,
by means of a fhallow dim, placed below the bell-
glafs, it is to be removed into the common water
pneumato-chemical apparatus*, where the air re-
maining may be  examined at large,  and with
great facility.
   When very foft and very pure  iron has been
employed in this experiment, and,  when the
combuftion  has been performed in the pureft re-
fpirable  or vital air, free from admixture of the
noxious  or mephitic part, the  air which remains


 * For a particular defcription of  th's apparatus, and
the manner of ufing it, and of many o:her proceiles with
the inftruments fitted for carrying them on,  fee  the third
part jf this work.----T. 
94
ELEMENTS
 after the combuftion, will be found as pure as it
 was before.   But it  is difficult to find iron en-
 tirely free from a  fmall portion of charry mat-
 ter, which is chiefly abundant in fteel: and it
 is likewife exceedingly difficult to procure pure
 air perfectly  free from fome  admixture of me-
 phitis, with  which it is  almoft always conta-
 minated.   That fpecies of noxious air does not,
 in the  fmalleft  degree, difturb the refult of the
 experiment,  as  it is always  found at the end
 exactly in the  fame quantity as  at  the begin-
 ning.
   I mentioned before, that we have  two  ways
 of determining  the  conftituent  parts  of atmo-
 fperic air, the method of  analyfis,  and that by
 fynthefis.  The calcination of mercury has  fur-
 nifhed us with an example  of each of thefe  me-
 thods ; fince, after  having  deprived it  of the re-
 fpirable part, by means  of the  mercury,  we
 have reftored it  again, fo as to recompofe an air
 precifely  fimilar to  that  of the  atmofphere.
 But we can  equally  accomplifh this  fynthetic
 compofition  of atmofpheric air,  by borrowing
 the materials of which it is formed from different
 kingdoms  of nature.  We fhall  fee  hereafter,
that,  when animal fubftances are  diffolved in
 the nitric  acid, a great quantity  of gas is difen-
 gaged, which  extinguifhes light, and is  unfit
 for animal refpiration, being exactly  fimilar to
 the noxious or mephitic part of atmofpheric air. 
OF  CHEMISTRY
95
And, if we take 73 parts, by weight, of this ela-
ftic fluid, and mix them with  27 parts of highly
refpirable air, procured  from calcined mercury,
we fhall  form an elaftic fluid  precifely fimilar
to atmofpheric air in all its properties.
   There are many other methods  of feparating
the refpirable from the  noxious part of the at-
mofpheric air,  which cannot  be taken notice of
in this place, without anticipating  information,
which properly belongs to the fubfequent chap-
ters.   The experiments already adduced,  may
fuffice for an elementary treatife :  and, in mat-
ters of this nature, the  choice of our  evidences
is  of far greater  confequence than  their num-
ber.
   I fhall clofe this article,  by pointing out the
property poffeffed by atmofpheric  air,  and all
the known gaffes, of diffolving water ;  which
circumftance it is of great confequence to attend
to in  all experiments of this  nature.  Mr Sauf-
fure found, by experiment, that a cubical foot
of atmofpheric air is capable of holding 12 grains
of water in folution*.   Other gaffes, as the car-
bonic acid, appear capable of diffolving a great-
er quantity:  but experiments are  ftill wanting

 * It is evident that the quanriry of vviter held in folo-
tion/by determinate quantities of the ditferent gafle«, muft
varyaccordingto thedegrees of temnerature andwcfiure.
--T. 
96         ELEMENT  S

by which  to  determine their  feveral  propor-
tions.  This  water, held in folution  by gaffes,
gives rife  to  particular phenomena,  which re-
quire great attention,  in  many  experiments,
and which  have frequently proved  the fource of
great errors to chemifts in determining  the re-
fults of their experiments. 
OF  CHEMISTRY.        fj
              CHAP.   IV.

Nomenclature  of the feveral Conftituent Parts of
               Atmofpheric Air.

      HITHERTO I have been obliged to make
       ufe of circumlocution, to exprefs the na-
 ture of the feveral fubftances which conftitute our
 atmofphere, having provisionally ufed the terms
 of refpirable, and noxious or non-refpirable parts
 if the air.  But  the inveftigations  I  mean to
 undertake require a more direct mode of ex-
 preflion;  and, having now endeavoured to give
 fimple anddiftinct ideas of the different fubftances
 which enter into the  compofition of the atmo-
 fphere, I fhall henceforth exprefs thefe ideas by
 words equally fimple.
   The temperature of  our earth  being  very
 near to that at which water becomes folid, and
 at which  reciprocally it changes from  folid to
 fluid—and as  this phenomenon takes place fre-
 quently under our obfervation—it has very na-
 turally followed,  that,  in the  languages of at
 leaft every climate fubject to any degree of win-
 ter, a term has been ufed for fignifying water in
 the ftate of folidity, or when deprived of its qa-
                       N 
 9*          ELEMENTS

 loric.   The fame precifion has not been found
 neceffary with refpect  to water  reduced to the
 ftate of vapour by an additional quantity of calo-
 ric.   Thofe perfons who do not make a particu-
 lar ftudy of objects of this kind, are ftill ignorant
v that  water, when in a  temperature only a little
 above the boiling heat, is changed into an elaftic
 aeriform fluid,  fufceptible, like all other gaffes,
 of being received and contained in veffels, and of
 preferving its'gaffeous form fo long as it remains
 at the temperature of  212°,  and under a pref-
 fure not exceeding 28 inches of the mercurial ba-
 rometer.  As this phenomenon has not been ve-
 ry generally obferved,  no language has ufed a
 particular term for expreffing water in this ftate*:
 and the  fame thing occurs with all fluids,  and
 all fubftances, which do not evaporate in  the
 common temperature, and under the ufual pref-
 fure of our atmofphere.
    For fimilar reafons, r.ames have not been given
 to the liquid or concrete ftates of moft of the
 aeriform fluids.  Thefe were not known to arife
 from  the combination  of caloric  with  certain
 bafes: and, as they had not been feen either in
 the liquid or folid ftates,  their exiftence, under
 thefe forms, was even unknown to  natural  phi-
 lofophcrs.


   * In Eigiilh, the word fltam is exclufively appropria-
 ted to water in the fttue of vapour.----T. 
         OF  CHEMISTRY.         99

   We have not  pretended to make any altera-
tion upon fuch terms as are fanctified by ancient
cuftom; and, therefore, continue to ufe the words
water and ice in their common acceptation.  We
likewife retain the word air, to exprefs that col-
lection of elaftic fluids which compofes our at-
mofphere.   But  we  have not thought it necef-
fary to preferve  the  fame refpect  for modern
terms, adopted by the latter philofophers, having
confidered ourfelves as at liberty  to reject fuch
as appeared liable to give erroneous ideas of the
fubftances they are meant to exprefs, and  either
to  fubftitute new terms,  or to employ the old
ones, after having modified them in fuch a man-
ner as to convey more determinate ideas.  New
words,  when  neceffary,  have been  borrowed
chiefly from  the Greek language, in fuch a man-
ner as to make their etymology convey fome idea
of what was  meant to be  reprefented  by them :
and we  have always  endeavoured  to make thefe
fhort, and of fuch a form as to admit of being
changed  into adjectives and verbs.
   Following thefe  principles, we have,  after
the example of Mr Macquer,  retained the term
gas, employed by VanHelmont; having arrang-
ed the numerous clafs of  elaftic aeriform  f uids
under that  name, excepting  only atmofpheric
air.  Gas, therefore, in our nomenclature, be-
comes a  generic  term, expreffmg the  fid left de-
gree of faturation in any body with caloric ; be- 
10©
ELEMENTS
ing, in fact, a term expreflive of a mode of ex-
iftence.   To diftinguifh the fpecies of gas,  we
employ a fecond  term derived  from the name
01 the bafe, which, faturated with caloric, forms
each particular gas.  Thus, we name water com-
bined to faturation with caloric, fo as to form an
elaftic  fluid, aqueous  gas;  ether,  combined  in
the fame manner, ethereal gas ; the combination
of alkohol with caloric, becomes aikoholk gas ;
and, following the fame principles, we have  mu-
riatic acid gas, ammoniacal gas, and fo on of eve-
ry fubftance fufceptible of being  combined with
caloric, in fuch a manner as to affume the gafieous
or elaftic aeriform  ftate.
   We have already feen, that the atmofpheric
fluid, or common air, is compofed of two gaffes,
or aeriform fluids  ; one of which  is capable, by
refpiration,  of contributing to  fupport  animal
life; and in it  metals are calculable, and com-
buftible bodies may  burn.   The other, on  the
contrary, is endowed with directly oppofite qua-
lities.   It cannot  be breathed*  by animals, nei-
ther will it admit of the combuftion  of inflam-
mable bodies, nor  of the calcination  of metals;
We have given to  the bafe of the former, which
is the refpirable portion of  atmofpheric air,  the

  * It may indeed he inspired into the lungs of animals,
but is then Cure to produce inftant death.----T. 
OF  CHEMISTRY.
101
name of .oxygen, from %^t, acidum, and ^i/*^**
gignor, becaufe one of the moft general proper-
ties of this bafe is to form acids, by combining
with many different fubftances.   The union of
this bafe with  caloric, which is  the fame with
what was formerly named pure, or vital, or high-
ly refpirable air, we now call oxygen gas.  The
weight of this gas,  at the temperature of 54.500,
and under a preffure equal to 28 inches of the ba-
rometer, is half a grain for each cubical inch near-
ly, or one ounce and a half to each cubical foot.
   The chemical  properties of the noxious por-
tion of atmofpheric air being hitherto but little
known, we have been  fatisfied to  derive  the
name of its bafe from its known quality of kil-
ling fuch animals as are forced  to breathe it;
giving it the name of azot, from the Greek pri-
vative  particle * and  &*, vita;  hence the name
of the noxious part of atmofpheric air  is azotic
gas.  The weight of this, in the fame tempera-
ture, and  under  the fame  p  effure,  is  1 oz. 2
drams and 48 grs. to the cubical foot, or 0.4444
of  a  grain to  the cubical  inch.    We cannot
deny, that this name appears fomewhat extra-
ordinary.   But this muft be the cafe with  all
new terms, which cannot be expected to  be-
come familiar until they have been fome time
in ufe.   We  long endeavoured  to  find a more
proper defignation without fuccefs.   It was at
firft propofed to  call it  alkaligen gas, as, from 
102
ELEMENTS
the experiments of Mr  Berthollet, it appears to
enter into the compofition of ammoniac, or vo-
latile alkali.  But then, we have as yet  no proof
of its making one of the conftituent elements of
the other alkalies; befides,  it is proved  to form
a part of the nitric acid, which gives  as good
reafon to have it called niirigen.   For thefe rea-
fons, finding it  neceffary  to  reject any r.ame
upon fyftematic principles, we have confidered
that we run no rifk  of  miftake in adopting the
terms  cf azot, .xA  azotic  gas, which  only ex-
prefs a matter of fact, or that  property which it
poffeifes, of depriving fuch animals as breathe it
of their lives.
   I fhould anticipate fubjects  more properly  re-
ferved  for the fubfequent  chapters,  were I in
this place to enter upon the nomenclature of the
feveral fpecies of gaffes.   It is fufficient,  in this
part of the work, to eftablifh the principles upon
which  their demoninations  are founded.  The
principal merit  of the nomenclature we have ad-
opted is, that, when once the fimple elementary
fubftance is diftinguifhed by an appropriate term,
the names  of all its compounds  derive readily,
and neceffarily, from this firft  denomination, 
OF  ^HEMISTRY.
              CHAP.  V.

Of the Decompofition of Oxygen  Gas by Sulphur,
   Phofphorus, and Carbon—and  of the  Forma*
   tion of Acids in general.


"jj-hN  performing experiments,  it is a  neceffary
JJL principle, which  ought  never to be  devia-
ted from, that they be Amplified as much  as
poffible, and  that every circumftance capable of
rendering their refults complicated,  be carefully
removed.   Wherefore, in the experiments which
form  the  object of this chapter, I have never
employed atmofpheric air, which is not a fimple
fubftance.  It is true, that the  azotic gas, which
forms a part of its mixture,  appears to be mere-
ly palahve  during  combuftion  and  calcination.
But,  befides  that it  retards  thefe  operations
very confiderably,  we are not certain but  it may
even  alter  their  refults in fome circumftances ;
for which reafon, I have thought it  necefary to
remove  even this  poffible caufe  of doubt,  by
making  ufe only of pure oxygen gas in the fol-
lowing experiments, which fhew the effects pro-
duced by  combuftion  in that gas.  I fhall ad-
vert to fuch differences as take  place in the  re-
fults of thefe, when  the oxygen  gas,  or pure
103 
l©4
ELEMENTS
vital air, is mixed, in  different proportions, with
azotic gas.
   Having filled a bell-glafs, A, PI. IV. fig. 3. of
between five and  fix pints meafure, with  oxy-
gen  gas,  I  removed it  from the water-trough,
where it  was filled, into  the  quickfilver  bath,
by means of a (hallow  glafs difh flipped under-
neath ; and having dried the mercury, I introdu-
ced 611 grains of Kunkefs phofphorus in two
little China cups,   like that  reprefented at D,
fig. 3. under the glafs A.   That I might fet fire
to each  of the portions of phofphorus feparately,
and to prevent the one from catching fire from
the other, one of the dilhes was covered with a
flat piece  of glafs.  I  next raifed the  quick-
filver in the  bell-glafs up  to EF, by  fucking
out a  fufficient  portion of gas  through the fy-
phon GHI.   After this, by means of the crook-
ed iron wire, fig.  16. made red hot,  I  fet fire
to the two portions of phofphorus fucceffively,
firft burning that  portion which was not cover-
ed by the piece of  glafs.   The  combuftion was
extremely rapid, being  attended by a very bril-
liant flame, and a confiderable difengagement of
light  and heat.   In confequence  of  the  great
heat induced, the gas was at firft much dilated ;
but foon after the mercury returned to its  level,
and  a confiderable abforption or diminution of
gas took place; at the fame time, the whole in- 
OF  CHEMISTRY
105
 fide of the glafs became covered with light white
 flakes of concrete phofphoric acid.
    At the beginning  of the  experiment,  the
 quantity of oxygen gas, reduced, as  before di-
 rected, to a common ftandard of thermonaetrical
 temperature and barometrical preffure, amount-
 ed  to  162 cubical inches; and, after the com-
 buftion was finiihed,  only 23! cubical inches,
 likewife reduced to the  ftandard,  remained; fo
 that the quantity of oxygen gas abforbed during
 the combuftion was 138? cubical inches,  equal
. to 69.575  grains.
   A part  of the  phofphorus  remained uncon-
 fumed in the  bottom  of the cups, which being
 wafhed on purpofe to feparate  the  acid, weigh-
 ed about 16'-grains;  fo that about 45 grains of
 phofphorus had  been confirmed.  But, as it is
 hardly pofiible to avoid an error of one or two
 grains,  I  leave  the number  fo far  qualified.
 Hence, as  nearly 45 grains of phofphorus had,
 in this experiment,  united with 69.375 grains
 of oxygen, and as no gravitating matter could
 have efcaped through the glafs, we have a  right
 to conclude, that  the weight of the fubftance re-
 fulting from the combuftion in form of white-
 flakes, muft equal that of the phofphorus and
 oxygen employed, which amounts to  114,3^5
 grains;   And we fhall  prefently find, that thefe
 flafces confifted entirely of a folid  or  concrete
acid.   When we reduce thefe weights to hun-
                    O 
ic6          E L E  M E  N  T S

dredth parts, it will be found  that ioo parts of
phofphorus  require 154 parts of oxygen  for fa-
turation ; and that this combination will produce
254 parts of concrete phofphoric acid, in form
of white fleecy flakes.
  This experiment  proves, in  the moft convin-
cing manner, that at a certain degree of tempe-
rature, oxygen poffeffes a ftronger  elective at-
traction,  or  affinity, for phofphorus than for ca-
loric ; and that, in confequence of this, the phof-
phorus attracts  the bafe of oxygen gas from the
caloric, which,  being fet free, fpreads itfelf over
the furrounding  bodies.   But, though this ex-
periment *be fo far perfectly conclufive, it is not
fufliciently rigorous;  for, in the apparatus de-
scribed above,  it is impoflible to  afcertain the
weight of the fakes of concrete acid which are
formed :  we can  therefore only determine  thi§
by  calculating  the weights of oxygen and phof-
phorus  employed.  But as,  in phyfics,  and in
chemiftry,  it is not allowable to fuppofe what is
capable of  being afcertained by direft  experi-
ment, I thought it neceffary to repeat this experi-
ment, as follows, upon a larger  fcale, and by
means of a different apparatus.
   I took a  large  glafs  balloon  A, PI. IV. fig. 4.
with an  opening of three  inches Jdiameter, to
which was  fitted  a cryftal ftopper, ground with
emery, and  pierced  with two holes for  the tubes
vyv, xxx.   Before fhutting the balloon with its 
OF CHEMISTRY.
107
 Copper, I introduced the fupport BC, furmount-
 ed by the china cup D, containing 150^  of
 phofphorus.   The ftopper was then fitted to the
 opening of the balloon, luted with fat lute, and
 covered with flips of linen fpread with quicklime,
 and white of eggs.  When the lute was perfect-
 ly dry, the weight of the whole  apparatus was
 determined to  within  a grain, or a grain and a
 half.  I next  cxhaufted the balloon, by means
 of an  air-pump  applied to the tube xxx, and
 then introduced  oxygen gas by means of the
 tube yyy, which  has a flop-cock adapted to it.
 This kind of  experiment  is moft  readily and
 moft exactly performed by means of the hydro-
 pneumatic  machine defcribed by Mr Meufnier
 and myfelf, in  the Memoirs of the Academy for
 1782, page 466, and explained in the latter part
 of this work,  with  feveral  important additions
 and corrections  fince  made  to it by Mr Meuf-
 nier.   With this inftrument we  can readily af-
 certain, in the moft  exact  manner,  both the
 quantity of oxygen gas introduced into the bal-
 loon, and  the quantity confumed  during the
 courfe of the experiment.
  When all things were properly difpofed, I fet
fire to  the  phofphorus with a burning-glafs:
The combuftion was extremely rapid,  accompa-
nied with a bright flame, and much heat.  As
the operation went on, large quantities of white
flakes gradually attached themfelves to  the in- 
io8
E  L E  M E N T S
ner furface of the balloon, until at  laft it was
rendered quite  opake.   The quantity of thefe
flakes  at  the end became fo  abundant, that,
though frefh oxygen gas was continually fup-
plied, which ought to have fupported the com-
buftion,  the phofphorus  became  extinguifhed.
Having allowed the apparatus to cool complete-
ly, I firft afcertained the quantity of oxygen gas
employed, and weighed the balloon  accurately,
before it  was opened.   I next wafhed, dried,
and weighed the fmall quantity of phofphorus
remaining in the cup, on  purpofe  to  determine
the whole quantity of phofphorus confirmed in
the experiment.   This refiduum of the phofpho-
rus was of a yellow ochrey colour.  It is evi-
dent, that by thefe feveral precautions, I could
eafily determine the weight of  the phofphorus
confumed ; the weight of the  flakes produced
by  the  combuftion; and the  weight  of the
oxygen which  had combined  with  the  phof-
phorus.
   This experiment gave  very nearly  the fame
refults with  the former ;  as it proved that the
phofphorus,  during its combuftion, had abforbed
a little more than one and a half its weight of
oxygen: and I learned with  more  certainty,
that the weight of the new fubftance,  produced
in the  experiment,  exactly equalled the fum
of the weights of  the phofphorus  confumed,
and oxygen  abforbed; which indeed was eafily 
OF  CHEMISTRY.      109
determinable a priori.   If the oxygen gas em-
ployed be pure, the refiduum after combuftion
is as pure as the gas  employed.   This proves
that nothing efcapes from the phofphorus,  ca-
pable of altering the purity of the oxygen gas,
and that the only action  of the phofphorus is to
feparate the oxygen from the caloric, with which
it was before united.
   I mentioned above,  that when any combufln-
ble body is burnt in a hollow fphere of ice, or
in an apparatus properly  conftructed upon that
principle,  the  quantity of ice melted during the
combuftion is  an exact meafure  of the quantity
of caloric difengaged.   On  this fubject the me-
moir given to the academy by M. de la Place and
myfelf,  A°. 1780, p. 355,  may be confulted.
Having fubmitted the combuftion of phofphorus
to this trial, we found that one pound of phof-
phorus melted  a little more than  100 pounds of
ice  during its combuftion.
  The combuftion of phofphorus fucceeds equal-
ly well in atmofpheric air as  in oxygen gas, with
this difference, that the combuftion is vaftlv flow-
er,  being retarded by the large proportion of a-
zotic gas mixed with the oxygen gas ; and that
only about  one fifth-part  of the air employed is
abforbed; becaufe,  as the oxygen gas only is
abforbed, the proportion of the  azotic gas be-
comes fo great towards the  clofe of the experi-
riment, as to put an end to the combuftion. 
no
ELEMENTS
   I  have  already fhewn,  that  phofphorus is
changed by combuftion into an extremely light,
white, flakey matter.   Its properties are likewife
entirely altered by this transformation.   Trom
being infoluble in  water, it becomes  not only
foluble, but fo greedy of moiftufe, as to attract
the humidity of the  air with aftonifhing rapidi-
ty.   By this means it is converted into a liquid,
confiderably more  denfe, and  cf mere fpecific
gravity than water.   In the ftate of  phofphorus
before  combuftion, it  has fcarcely any fenfible
tafte ;  by its union with  oxygen it acquires an
extremly fharp and four tafte.   In a word, from
one of the clafs of combuftible bodies, it is chan-
ged  into  an  incombuftible  fubftance, and be-
comes one of thofe bodies called  acids.
   This property of a combuftible fubftance to
be  converted  into an acid, by the  addition of
oxygen, we fhall prefently find belongs to a great
number of bodies : wnherefore, a ftrict logic re-
quires that we fhould adopt a  common term for
indicating  all  thefe operations which produce
analogous refults.  This is the true wray to fim-
plify the  ftudy of fcience, as it would be quite
impoffiblc  to  bear  all its  fpecifical  details in
the  memory,  if they were not claflically ar-
ranged.   For  this reafon, we fhall diftinguifh
the converfion of phofphorus  into an acid,  by
its  union with oxygen,  and  in  general every
combination of oxygen with a combuftible fub- 
OF CHEMISTRY.
in
fiance, by the term  of oxygenation:  FrOm  this
I fhall adopt  the verb to oxygenate; and of con-
fequence fhall fay, that in  oxygenating phofpho-
rus we convert it into an acid.
   Sulphur is  likewife a combuftible body ; or, in
other words, it is a body which  poffeffes  the
power of decompofing oxygen gas,  by attract-
ing the oxygen  from  the caloric with which it
was combined.   This can very eafily  be proved,
by means of experiments quite fimilar to thofe
we have given with phofphorus.    But it is ne-
ceffary to premife, that in  thefe operations with
fulphur, the fame accuracy of refult is not to
be expected as with phofpliorus ;  becaufe  the
acid which is formed by the combuftion of ful-
phur is difficultly condenfible ;  and becaufe ful-
phur burns  with more difficulty, and is foluble
in the different gaffes.   But I can  fafely affert,
from my own  experiments,   that  fulphur  in
burning abforbs oxygen gas ;  that  the refulting
acid is  confiderably heavier  than  the  fulphur
burnt;  that  its  weight is  equal to  the Aim of
the  weights  of the  fulphur which  has been
burnt, and of the oxygen abforbed ;  and laftly,
that  this acid is  weighty,  incombuftible,  and
mifcible with water in all proportions.  The onlv
uncertainty remaining on this head,  h with
regard to the proportions of fulphur and of
oxygen which enter into the compofition of the
acid. 
112
ELEMENTS
    Charcoal, which, from all our prefent know-
 ledge regarding it, muft be  confidered as a fim-
 ple combuftible body*,  has likewife the proper-
 ty of decompofing oxygen gas, by abforbing its
 bafe from  the  caloric.   But the acid refulting
 from  this  combuftion does not condenfe in the
 common temperature. Under the preffure of our
 atmofphere, it  remains  in the ftate of gas, and
 requires a large proportion of water to combine
 with, or be diffolvcd in.  This acid has, how-
 ever,  all the  known properties of other acids,
 though  in a weaker degree ; and combines, like
 them with all the bafes  which are fufceptible  of
 forming neutral falts.
   The combuftion of charcoal in oxygen gas,
 may be effected like that of phofphorus  in the
 bell-glafs, A, PI. IV.  fig. 3.  placed over mer-
 cury.   But, as the  heat of red-hot iron  is not
 fuhleient  to fet fire  to  the charcoal, we muft
 add a fmall  morfel  of tinder,  with  a  minute
 particle of phofphorus, in the fame manner as is
 directed in  the  experiment for the  combuftion
 of iron.  A detailed account of this experiment •
 will be  found  in the memoirs of the academy


  * This afiertion is to he underftood of the pure  combuf-
tible part of charcoal, which, in the nomenclature, is
i.anicd carbon, carbonuvi, to  diftinguifli it !V' m charcoal,
charbni, cm-bo. The  latter, befides  carbon,  contains
fjmu" !ncom':uflVjle earth, and certain Cwt1..----T. 
OF   CHEMISTRY.
"3
 for 1781, p.  448.  By that experiment it ap-
 pears, that  28 parts  by weight  of carbon re-
 quire  72 parts of oxygen  for  faturation ;   and
 that the aeriform acid produced is precifely equal
 in weight to the fum of the weights of the char-
 coal confumed, and oxygen gas employed, during
 the combuftion.   This aeriform acid was called
 fixed or fixable air by the chemifts who firft difco-
 vered it.  They did not then know whether it was
 air refembling that of the atmofphere,  or fome
 other  elaftic fluid,  vitiated and  corrupted by
 combuftion.   But fince it  is now  afcertained to
 be an acid, formed  like all others by  the  oxy-
 genation  of its peculiar bafe, it is obvious that
 the name of fixed air is quite ineligible*.
   By  burning charcoal in the  apparatus men-
 tioned, p.  60, Mr de la Place and I found  that
 one lb. of charcoal melted 96.375/^.  of ice  ;
 that, during the combuftion, 2.5714 lbs. of oxy-
 gen were  abforbed; and that 3.5714/&r. of acid
 gas were  formed.  This gas weighs 0.695 Part*
 of a grain for each cubical inch, in the  common
                        P


 * It may  be proper to remark, though here omitted
by  the  author, that, in conformity  with the general
principles of the new nomenclature, this  acid is by Mr.
Lavoifier and bis colleagues called the carbonic acid, and
when in the aeriform ftate, carbonic acid gas.----T. 
ii4          ELEMENTS

ftandard temperature  and  preffure mentioned
above ; fo that 34242* cubical inches of acid gas
are produced by the combuftion of one pound of
charcoal.
  I might multiply thefe experiments, and fhow,
by a numerous fucceflion of facts, that all acids
are formed by the combuftion of certain fubftan-
ces.  But I am prevented from doing fo in this
place, by the plan which 1 have laid down, of
proceeding  only from facts already afcertained
to  fuch  as  are unknown,  and of drawing my
examples only from circumftances already ex-
plained.  In  the  mean  time,  however,   the
three examples above  cited, may  fuffice for gi-
ving  a  clear  and accurate conception  of the
manner  in  which acids are formed.   By  thefe
it may be clearly feen, that oxygen is an  ele-
ment common to them all, and which confti-
tutes or produces their acidity ; and  that they
differ from  each  other, according to the feveral
natures of  the oxgenated  or  acidified  fubftan-
ces.  We muft, therefore,  in every acid, care-

 * Some error mud have crept into Mr. Lavoifier's calcu-
lation ; for, on the data here given, the number of cubi-
cal inches of gas ought to have been 47358.3 ; as 3.5714
lbs. of carbonic acid gas, or  32gr/'.02:4 grs. when di-
vided by .695, the weight of  a cubical  inch, give  this
 corrected quotient.----T. 
         OF  CHEMISTRY.        n$

fully diftinguifh  between  the acidifiable  bafe,
which Mr de Morveau calls  the radical, and
the acidifying principle, or oxygen. 
n6
ELEMENTS
              CHAP  VI.

Of the Nomenclature of Acids in general, and par-
  ticularly of thofe drawn from Nitre  and Sea-
  Salt.


  IT becomes extremely  eafy, from the  princi-
    ples laid down in the preceding chapter,  to
eftablifh a fyftematic nomenclature for   the  a-
cids.   The  word  acid being ufed as a  generic
term, each acid  falls  to  be diftinguifhed in lan-
guage,  as in nature, by the name of its bafe  or
radical.  Thus, we give  the generic  name of
acids to the products of the combuftion or oxy-
genation of phofphorus, of fulphur, and of car-
bon ; and thefe products are refpettively named,
the phofphoric acid, the fulphuric acid, and the
carbonic acid.
   There  i.*, however,  a  remarkable  circum-
ftance  in the oxygenation of combuftible bo-
dies, and of a part of fuch  bodies as are con-
vertible into acids, that  they  are fufceptible of
 different  degrees of faturation  with oxygen;
 and that the refulting acids, though formed  by
 the union of the fame elements,  are poffeffed of
 different  properties,  depending  upon  that dif-
 ference of proportion.   Of this,  the phofphoric 
OF  CHEMISTRY
117
 acid, and,  more  efpecially,  the  fulphuric, fur-
 nifh us  with examples.  When fulphur is com-
 bined with  a  fmall  proportion of  oxygen, it
 forms,  in the firft or lower degree  of oxygena-
 tion, a volatile acid, having a penetrating odour,
 and poffeffed of very peculiar qualities.   By a
 larger proportion of oxygen, it is changed into
 a  fixed,  heavy acid,  without any odour,  and
 which, by combination with other bodies, gives
 products quite different from thofe  furnifhed
 by the former. In this inftance, the principles of
 our nomenclature  feem to fail :  and it appears
 difficult  to derive fuch terms from  the name of
 the acidifiable  bafe, as fhall diftinctly exprefs
 thefe two degrees of faturation, or oxygenation,
 without  circumlocution.  By reflection,  how-
 ever, upon  the  fubject, or perhaps  rather  from
 the neceflity of the cafe, we have thought it al-
 lowable to  exprefs thefe varieties in the oxyge-
 nation of the acids, by fimply varying the termi-
 nation of their fpecific names.  The volatile acid"
 produced from fulphur was anciently  known
 to  Stahl under the  name  of fulphurous acid *.

  * The term formerly ufed by the Englifh chemifts for
this acid was  written  ful?»hur<?oiis ; but I have thought
 proper to fpell it as above, that  it may better conform
 with the fimilar terminations of nitrous, carbonou*, &c.
 to b? ufed hereafter.   In general, I have ufed  the Fnglifli
 terminations ic and ous to tranflate the terms of the Au-
 thor which end with iqne and eux, with hardly sny other
 alterations.----T. 
n8         ELEMENTS

We  have preferved that term for this  acid from
fulphur  under-faturated  with   oxygen;  and
diilinguifli the other, or completely  faturated
or oxygenated acid,  by the  name  of fulphuric
acid.    We fhall therefore fay, in this new che-
mical  language,  that fulphur,  in  combining
v ith oxygen,  is  fufceptible  of  two degrees of
faturation ; that the firft or leffer degree, con-
flitutes  fulphurous acid,  which is  volatile and
penetrating ; while the fecond,  or higher de-
gree of faturation,   produces  fulphuric  acid,
which  is fixed and inodorous.  We fhall  adopt
this  difference of  termination for all  the  acids
which  affume  feveral  degrees  of faturation.
Hence we have a phofphorus and a phofpho-
ric acid, an acetous and an acetic acid ;  and fo
on, for others in fimilar circumftances.
  This part  of chemical  fcience would   have
been extremely  fimple, and  the nomenclature
of the acids would not  have been at  all per-
plexed, as it is now in the old nomenclature, if
the bafe  or radical of each acid had been known
when the acid itfelf was difcovered.'    Thus, for
inftance,  phofphorus  being a known fubftance
before  the  difcovery of its acid, this latter was
rightly diftinguifhed by a  term  drawn from the
name of its acidifiable bafe.   But when, on the
contrary, an  acid happened to  be difcovered
before its bafe, or rather, when  the  acidifiable
bafe from which it was formed, remained  un- 
OF  CHEMISTRY.        119
known, names were adopted for the two which
have  not  the  fmalleft conne&ion: and  thus,
not only  the  memory became burdened with
ufelefs appellations,  but the minds of fludents,
nay even  of experienced chemifts, became fil-
led with falfe  ideas, which time and refle&ion
alone  are capable  of eradicating.  We may
give an  inftance of this confufion with refpect
to the acid of fulphur.  The former chemifts,
having procured this  acid from the vitriol of
iron, gave it the name of the vitriolic acid from
the  name of the fubftaace which produced it:
and  they were then ignorant that the  acid pro-
cured  from fulphur by combuftion was exactly
the fame.   The fame thing happened  with the
aeriform  acid,  formerly called fixed air. It not
having been known, that this acid was the refult
of combining  carbon with oxygen, a variety of
denominations  have been given  to it,  not one
of which  conveys jufl ideas of its nature or ori-
gin.
   We have found it extremely eafy to correct
and modify the ancient  language with refpect
to thofe acids which proceed from known bafes;
having converted the name of vitriolic  acid into
that of fulphuric, and the name of fixed air in-
to that of carbonic acid.  Bat it is impoftible
to follow this  plan with the acids  whofe bafes
are  ftill   unknown.   With thefe we have been
obliged to ufe a contrary plan,  and, inftead of 
120
ELEMENTS
 forming the name of the acid from  that of  its
 bafe, have  been  forced  to denominate its un-
 known bafe from the name of the known acid,
 as happens  in the cafe of the acid which is pro-
 cured from fea fait.
   To difengage this acid from the alkaline bafe
 with  which  it is  combined,  we  have only  to
 pour fulphuric acid upon fea-falt   Immediately
 a  brifk effervefcence  takes  place,  white vapours
 arife, of a  very penetrating odour,  and, by gen-
 tly heating the mixture, all the  acid is  driven
 off.   As, in  the common temperature and pref-
 fure of our atmofphere, this acid is naturally in
 the ftate of gas, we  muft ufe particular precau-
 tions for retaining it in proper veffels.   For fmall
 experiments, the moft fimple and  moft commo-
 dious apparatus confifts of a fmall  retort G, PI.
 V. fig. 5.  into which  the fea-falt is introduced,
 well dried*:  we then  pour on  fome concentrated
 fulphuric  acid,  and  immediately introduce the
 beak of  the retort  under little jars or  bell-
 glaffes A,  fame  Plate and Fig. previoufly fil-
 led with quickfilver.    In  proportion  as the acid
 gas  is difengaged, it  paffes  into the jar, and
 gets to the top  of the quickfilver which it dif-

  * For this purpofe, the operation called  decrepitation
is uled, which confifts in  fubjeclingit to nearly  a red
heat, in a proper veflel,  1b as to evaporate all its water
cf crviLllizatlon.----T. 
OF   CHEMISTRY.
121
 places.   When  the  difengagement of the  gas
 flackens, a gentle  heat is applied  to the retort,
 and  is gradually increafcd,  till nothing more
 paffes over.   This acid  gas has a  very  ilrono-
 affinity with water, which  abforbs  an enormous
 quantity cf it.  This  is proved by introducing a
 very thin layer of water into the glafs which con-
 tains the gas ;  for, in an inftant, the whole acid
 gas difappears, and combines with the water.
   This latter circumftance is taken advantage of
 in laboratories and manufactories, on purpofe to
 obtain the acid of fea-falt in a liquid form ; and
 for this purpofe the apparatus PI. IV. Fig. i. is
 employed.   It confifts of a tubulated retort  A,
 into which the fea-falt, and after it the fulphuric
 acid, are. introduced through the opening H ;
 of  the  balloon or recipient c, b, intended for
 containing tile fmall quantity of liquid  which
 paffes over during the procefs ; and of a fet of
 bottles with two mouths,  L, L, L, L, half filled
 with water, intended  for abforbing the  gas dif-
 engaged by the diftillation.  This apparatus will
 be more amply defcribed in the latter part of this
 work.
  Although we have not yet been able,  either
 to compefc or to decompound this acid  of fea-
 falt, we  cannot have the fmalleft doubt that,
}ike all other acids, it  is compofed by the  union
 of oxygen with an acidifiable bafe.   We have
 therefore  called  this  unknown  fubftance the 
122
ELEMENTS
 muriatic bafe, or muriatic radical,  deriving  this
 name,  after the  example of  Mr Bergman and
 Mr de  Morveau, from the Latin  word muria,
 which  was  anciently  ufed to  fignify  fea-falt.
 Thus, without being able exactly  to  determine
 the component parts of muriatic acid,  we defign
 by that  term a  volatile acid,  which retains the
 form of gas in the common temperature  and
 preffure of  our  atmofphere ; which  combines
 with great facility, and  in great quantity, with
 water;  and  whofe acidifiable bafe adheres fo
 very intimately with oxygen, that no  method
 has hitherto * been devifed for feparating them.
 If ever this acidifiable bafe of the muriatic acid is
 difcovered to be a known fubftance, though now
 unknown in that capacity, it  will be requifite to
 change its prefent denomination for one analo-
 gous with that of its bafe.

            »
  * Dr.  Girtanner is faid  to have  lately difcovered that
Hydrogen is the bafe or radical of this acid.  Should this
difcovery be confirmed, the terms vvi'l here require fome
farther al'e  ation,  in conformity with the general prin-
ciples of the new nomenclature.   At any rate, 7/iuriogen
may be employed to denominate the bafe of  the muria-
tic acid, till its nature be unequivocally determined:
and, if the difcovery attributed to  Dr. Girtanner be af-
certained, the common bafe of water and muriatic acid
will more properly fill to be named by this new term,
than by that of Hydrogen.----T. 
OF  CHEMISTRY.
123
    In  common with fulphuric acid,  and feveral
 other acids, the  muriatic is capable of different
 degrees of oxygenation :  but the excefs of oxy-
 gen produces quite contrary effects upon it from
 what the fame circumftanee produces upon the
 acid of fulphur.  The lower degree  of oxygena-
 tion converts  fulphur  into a  volatile  gaffeous
 acid,  which  only mixes in fmall  proportions
 with water ; while a higher  oxygenation forms
 an acid  poffefling much ftronger acid  proper-
 ties, which is  very  fixed, and  cannot remain in
 the ftate of gas  but  in a very high temperature,
 which  has no fmell, and which mixes in  large
 proportion with water.  With muriatic  acid,
 the direct reverfe takes  place.  An additional
 faturation with oxygen renders it more volatile,
 of a more penetrating odour, lefs mifcible with
 water, and  diminifhes  its acid  properties.  We
 were at firft inclined to have denominated  thefe
 two degrees of faturation  in the  fame  manner
 as  we  had done with  the acid of fulphur, cal-
 ling the  lefs  oxygenated  muriatous acid,  and
 that which is more  faturated with oxygen, mu-
riatic acid:  But,  as  this  latter gives very par-
ticular refults  in its combinations, and  as no-
thing analogous  to it is yet known  in  chemif-
try, we  have  left the  name  of  muriatic  acid
to the  lefs faturated,  and  give the latter the 
 if 4          ELEMENTS

 more compounded- appellation of oxygenated mu-
 riatic acid*.
   Although  the  bafe  or  radical  of the acid
 which is  extracted  from  nitre or  faltpetre  be
 better known,  we   have judged proper  only
 to modify its name in the fame manner  with
 that of the muriatic acid.   It  is  procured from
 nitre, by  the intervention  of fulphuric acid,
 by a  procefs  fimilar to that  defcribed  for ex-
 tracting the  muriatic  acid, and  by  means of
 the fame  apparatus, PI. IV.  Fig i.   In propor-
 tion as the acid  paffes  over,  it  is in part ccn-
 denfed in  the balloon or recipient;  and the reft
 is abforbed by the water contained in the bot-
 tles L, L,  L, L ; the water becomes firft  green,
 then  blue,  and at laft yellow, in proportion to
 the  concentration of the acid.   During  this o-
 p.. ration, a large quantity  of oxygen gas, mixed
 with a fmall  proportion of azotic gas, is difen-
 o-po-.'->(!
   This acid, like all  others, is compofed of oxy-
 gen,  united to an acidifiable  bafe, and is even
 the firft acid in which  the exiftence of oxygen

  * The compound term murioxic  a a J might ferve verv
con enirptly ior expreffingrhis ft ,re of the muriatic acid.
In (tndl conVrmhy w:th the  general  principles of the
ne \ ..hemicA philofophy and its nomen lauire, it mould
have beenc,>Ued/«/>:T.ow-«^.</, ;nf}ead  of oxygenated
muriatic acid ; for all acids  are oxygenated____T. 
OF  CHEMISTRY.
I25
was well  ascertained.   Its  two condiment ele-
mens are  but  weakly  unit, d, and are eafily
feparated,  by  prefenting any  fubftance  with
which oxygen has a ftroegar affinity than whh
t aj  acidifiable bafe peculiar to this acid.  By
fome 'experiments of this kind, it was firft dif-
covered that azot, or the bafe of mephitis or of
azotic gas,  conftituted   its  acidifiable bafe  or
radical ;   and  confequently  that  the  acid  of
nitre was really an  azotic acid, having azot for
its bale, combined with oxygen.  For thefe rea-
fms, .that  we  might be confiftent  with  our
principles,  it appeared neceffary, either to  call
the  acil azotic,  or  to name the bafe nitric ra-
dical; but  from either  of thefe we were  dif-
fused,  by  the following  considerations.  It
feemed  difficult  to  change  the name of  nitre
or  Idrpetre, which  have been  univerfally  ad-
opted in  fociety, in manufactures,  and in  che-
miftry ; and, on  the other  hand, azot having
been difcovered by  Mr.  Berthollet to  be  the
bafe of volatile alkali, or  ammoniac, as .well  as
of this acid, we t' ought  it  improper  to call it
nitric  radical.   We have therefore  continued
the term of azot to the  bafe  of  that  part  of
atmofpheric  air which  is likewife   the nitric
and  ammoniacal radical; and we have named
the acid of nitre, in its  lower and  hio-hcr de-
grees of oxygenation, nitrous  acid  in  the for- 
 126          ELEMENTS

 mer, and  nitric acid in the latter ftate;  thus
 preferving its former appellation properly modi-
 fied.
   Several  very refpe&able chemifts have dif-
 approved of this deference for the old terms,
 and wifhed us  to  have perfevered in perfecting
 a new chemical language, without paying  any
 refpe£f. to ancient ufage ;  fo that, by thus fleer-
 ing a  fort  of middle courfe,  we have  expofed
 ourfelves to the cenfures of one feet  of che-
 mifts, and  to the expoftulations of the oppofite
 party.
   The acid of nitre is fufceptible  of affuming a
 great number of feparate ftates, depending up-
 on its degree of oxygenation, or upon the pro-
 portions  in which azot and oxygen enter into its
 compofition.  By a firft or loweft degree of oxy-
 genation, it forms a particular  fpecies of gas,
which we  fhall continue to  name nitrous gas ;
this is compofed nearly of two parts,  by weight,
of oxygen  combined with one part  of azot;
and in this ftate it is  not mifcible with water.
In this gas, the  azot is by no means fully fatu-
rated  with  oxygen;  but, on  the contrary, has
ftill a very  great affinity for that element, and
even  attracts  it  from  atmofpheric air,  imme-
diately upon getting  into contact with it.  This
combination  of nitrous gas with the oxygen gas
contained in atmofpheric air, has even become 
OF. CHEMISTRY.
127
 one of the methods for determining the quantity
 of oxygen  gas mixed  with any portion of air ;
 and confequently is ufed as a teft for afcertainino-
 its degree of falubrity,
   The further  addition of  oxygen  converts
 the  nitrous gas into a,powerful acid, which
 has a ftrong  affinity with water,  and  which
 is itfelf fufceptible of various additional  degrees
 of oxygenation.   When  the  proportions  of
 oxygen  and   azot  are  below three  parts, by
 weight, of the  former, to one  of the latter, the
 acid  is red coloured, and emits copious fumes.
 In this ftate,  by the application of a gentle
 heat,  it gives  out nitrous gas;  and we  term
 it, in  this  degree  of oxygenation, nitrous  acid.
 When four parts, by weight, of oxygen, are
 combined  with one  part  of azot,  the acid  is
 clear  and  colourlefs; more  fixed  in  the fire
 than  the  nitrous  acid; has  lefs  odour, and
 its conftituent  elements  are more firmly uni-
 ted.   This  fpecies of acid, in conformity with
 our principles  of nomenclature, is called  nitric
 acid.
   Thus,  nitric acid  is  the acid  of nitre, fur-
 charged with oxygen: nitrous  acid is the acid
 of nitre furcharged  with azot, or, what is the
fame thing,  with nitrous  gas : and this latter is
azot not Sufficiently faturated  with oxygen  to
poffefs the properties of an acid.  To this, lat- 
123
ELEMENTS
ter degree of oxygenation, we have  afterwnab,
in the courfe of  this  work, given the generical
name of oxyd*»


  * In drift conformity with the prhc'ples of the new
nomeocla'ure, bat whi-h rhe author has given  his  re::-
fons for deviating frum in this iii'lance,  the foihv ins*
ought to have  been  the terms  for azot, vi  its fever. 1
degrees of oxvgenatun: Azot, azotic  gas, (az >t corv'-i-
ned with c-jloric),  azotic ox\ d gas,  azotous acid,  and
azotic acid,----T". 
OF CHEMISTRY.
129
CHAP.   VII.
■ Of the Dccompfition of Oxygen  Gas by means  of
    Metals, and the Formation of Metallic Oxyds.


      OXYGEN  has a  ftronger affinity with me-
       tals that are heated to a certain degree,
 than with caloric.   In confequence of this^ all
 metallic bodies, excepting gold,  filver, and da-
 tma, have the property of  decompofing  oxy-
 gen  gas, by attra-aing its bafe  from the caloric
 w.tn which  it is  combined.  We have  alrea-
 dy  fiown in  what  manner  this  decompofition
 is effected by means of mercury and iron ; hav-
 ing obferved, that, in the cafe of the firft, it
 muft be confidered as a kind of gradual com-
 buftion, whereas, in the  latter, the combuftion
 is extremely rapid, and is attended with a  bril-
 liant  flame.  The ufe of the heat employed in
thefe operations  is to feparate the particles of
the metal from each other, and to diminim their
afiinity of  cohefion  or aggregation,  or,  what
is  the  fame tiftag, their  mutual  attraction for
each other.
   The ahiblu'e weight of all metallic fubftan-
ces is augmented  in proportion to the quantity
                      R 
130
ELEMENTS
of oxygen they abforb ; they, at the fame time,
lofe their  metallic  fplenior, and are  reduced
to the aopearance  of  an  earthy pulverulent
matter : In this ftate, metals muft not be confi-
dered  as  entirely faturated with  oxygen, be-
caufe their action upon this element is  counter-
balanced by the power of affinity between  it
and the caloric.  During the calcination of me-
tals, the oxygen is therefore  acted upon by
two  feparate  and oppofite powers, that  of its
attraction for  caloric,  and  that exerted by the
metal; and it  only tends to unite with the me-
tal in confequence of the excefs of the  latter
power over the former, which is, in  general,
very   inconfiderable.   Wherefore,  when me-
tallic fubftances are oxygenated  in  atmofpheric
air,  or in oxygen gas, they are not converted
into  acids, like fulphur, phofphorus,  and car-
bon, but  are  only changed into intermediate
fubftances, which,  though  approaching  to the
nature of falts,. have not acquired all the /aline
proper ftes.
   The older chemifts  have affixed the name of
calx not only   to  metals in this ftate, but to eve-
 ry body which has been  long  expofed  to the
 action of fire  without  being melted.   They
 have  employed  this word calx  as  a generical
 term; under  which  they confound calcareous
 earth, which, from  a neutral   fait,  which  it
 really was before calcination,  has been  chan- 
OF   CHEMISTRY.
I3I
  ged by fire into  an earthy  alkali,  by loftng half
  of its weight; and metals, which, by the fame
  means, have joined themfelves to a new  fub-
  ftance, the added quantity of which often  ex-
  ceeds half their weight,  and by the  addition of
  which they had  been changed almoft into the
  nature of acids.   This mode of claffiTying fub-
  ftances, of fo very oppofite  natures,  under the
  fame generic  name,  would have  been  quite
  contrary to our principles of nomenclature ; efpe-
  cially as, by retaining the  above term for  this
  ftate of metallic  fubftances, wc muft  have con-
  veyed very falfe ideas of its nature.   We have,
 therefore,  laid afide the expreffion metallic calx
 altogether, and have fubftituted in its  place  the
 term oxyd, from the Greek word 6s^.
   By this readinefs for fupplying appofite  terms,
 it is  evident that the  language  we have  adopt-
 ed is both copious and expreffive.  The firft
 or loweft degree of oxygenation in bodies, con-
 verts  them into oxyds ;   a fecond degree  of ad-
 ditional  oxygenation  conftitutes that  clafs of
 acids, of which  the fpecific names,  drawn from
 their  particular bafes,  terminate in  oas, as  the
 nitrous  and fulphurous  acids ; the third degree
 of oxygenation changes  thefe into that diviiion
 of acids, which are  diftinguiflied by the termi-
nation in  ic, as  the nitric and fwuauric acids;
and laftly,  we can exprefs a fourth, or hi'dieft
degree of oxygenation, by adding the word cxy- 
132
E  L  E  Id  E  N  T  S
genated to the  name of the acid, as  has been
already done with the oxygenated muriatic acid.
   We have not confined the term oxyd to the
purpofe of expreffing the combination of metals
with oxygen,  but have  extended it  to  fignify
that firft degree of oxygenation  in  all bodies,
which, whkout converting  them into  acids,
caufes them to approach  to  the nature of falts.
Thus, we give the name of oxyd of fulphur to
that  foft fubftance  into which fulphur is  con-
verted by  incipient,  or imperfect combuftion ;
and we call the  yellow matter  left by phofpho-
rus, after combuftion, by  the  name of oxyd of
phofphorus.  In  the  fame  manner, nitrous  gas,
which is azot in its firft degree of oxygenation,
is the oxyd of azot*.  We have likewife oxyds in
great  numbers  from the vegetable and  animal
kingdoms ; and I  fhall fhew, in the fequel, that
this new language throws great light upon all the
operations of art and nature.
   We  have already obferved, that almoft all
the  metallic oxyds have  peculiar and perma-

  * Mr. Lavoifier here ufes the term oxyd of azot, but
it is no where elfe adopted in the new nomenclature; j
though, as  I have mentioned in a former note, it is more
legitimate than the term nitrous gas ; which laft he has
retained, both becaufe it has  long been employed, and
chiefly becaufe,  as a familiar term  in chemiftrv, it  con-
veys no ideas contradiclory to the real nature of the fub-
ftance it is meant  to exprefs----T. 
          OF  CHEMISTRY       133

nent colours.  Thefe vary not only in the  dif-
ferent fpecies of metals, but even according to
the various degrees of oxygenation in the fame
metal.   Hence  we  are under the necefnty of
adding two epithets  to each  oxyd, one of which
indicates  the metal  oxyd.:t:dr:,  while the other
indicates   the  peculiar  colour  of  the  oxyd.
Thus, we have the black oxyd of iron, the  red
oxyd  of  iron, and  the yellow oxyd  cf iron  ;
which exprefnons refpedtively anfwer to the old
unmeaning terms of martial  ethiops,  colcothar,
and ruft of  iron, or ochre.   We have likewife
the grey,  yellow, and  red oxyds  of lead, which
 anfwer to  the equally  falfe or infignificant old
terms, litharge, afhes of lead, mafficot, and mi-
nium.
   Thefe denominations  fometimes become ra-
ther  long,  efpecially when we  mean to indi-
cate whether the- metal has been  oxdyated in
the air, by detonation with  nitre,  or by means
of acids;  but then  they always .convey  juft

  * Here we fee the word o^-yd converted into the verb
to  oxydate,  oxydated, oxydatinj, after  the fame manner
with the derivation of the verb to oxygenate,  oxyp -v. ate J
oxygenating, from the word oxygen.  I am not clear of
the abfolute neceflity of this fecond verb here firft in-
troduced, but think that, in a woik of  this  nature,  it
is  the duty of the tranflator to neglecl every other conli-
deration for the fake of ftrict fidelity to the ideas  of his
author.—_T. 
*34
ELEMENTS
and accurate ideas of the correfponding objects
which we wifh to exprefs by their ufe.   All  this
will be rendered perfectly clear and diftinct by
means of the  tables which are added to  this
work. 
OF  CHEMISTRY.
               CHAP   VIII.

Of the Radical Principle of Water, and ef its
       Decompofition by Charcoal and Iron.


     UNTIL very lately, water has always been
       thought   a  fimple fubftance;  infbmuch
that the  older  chemifts confidered it as an ele-
ment.   Such it undoubtedly  was to them as
they were unable to decompofe it; or, at leaft
fince the decompofition which took place daily
before their eyes, was  entirely unnoticed.  , But
we mean to prove, that water is by no means a
fimple or  elementary  fubftance.  I  fhall  not
here pretend to give the hiftory of this  recent,
and hitherto contefted  difcovery, which is de-
tailed in the Memoirs ofthe Academy for 1781 •
but  fhall  only  bring forward  the  principal
proofs  ofthe decompofition, and  compofition of
water; and I may venture to fay, that  thefe will
be convincing to fuch as  confider them  impar-
tially.                                   r

              Experiment Firft.

  Having fixed  the glafs tube EF, PI. VII. Fio-.
11. of from 8  to 12  lines diameter, acrofs°a 
ij6         E  L  E  M E N T S
furnace, with a fmall inclination from EtoF.;
lute the fuperior extremity E to the glafs retort
A, containing a determinate quantity of ciftil-
led water; and to the fuperior cxtremhy F, lute
the worm SS, fixed into the neck of the doubly
tubulated bottle H ; which laft lias the bent tale
KK adapted to one of its openings,  in fuch a
mannefjas to convey fuch aeriform fluids or gaffes
as may be  difengaged,  during the experiment,
into a  proper apparatus for determining their
quantity and. natu; e.                       ,,«,
   To render the. fuccefs of this experiment, cer-
tain, it is neceffary that the  tube El'' be made
of well annealed and difficultly fufible glafs, and
tfiat it be coated over with  a lute compofed of
clay mixed  with powdered ftone ware ; befides
which, it  muft be fupported about its middle by
means of an iron bar paifed through the furnace,
left ft fhould foften and bend, during tee e :i;e-
riment.  A tube of -China-ware or  porcelain,
would anfv/er  better than one  of glafs for t^iis
experiment, were it  net difficult to procure one
fo entirely free from pores as to prevent the paf-
fage of the air or vapours.
   When things are thus arranged, a fire is light-
ed in the furnace EFCD, which  is fupported of
fuch a ftrength  as tq keep the tube EF red hot,
but not to make it melt; and, at the fame time,
fuch a  fire is kept up in the furnace VVJX, as 
        OF  CHEMIST RY.        137

 to keep the water in the  retort A continually
 boiling.
   In proportion as  the water, in the retort A,
 is evaporated, ft fills the tube EF, and drives out
 the air contained through the tube KK.  The a-
 queous gas formed by evaporation, is  condenfed
 by cooling in the worm SS, and falls, drop- by
 drop, into the tubulated bottle H.  Having con-
 tinued this operation until  all the water be eva-
 porated  from the retort,  and  having carefully
 emptied  all the veffels employed, we find  that a
 quantity  of water has paffed over into the  bottle
 H,  exa&iy equal to what was before  contained
 in the retort A,  without any  difengagement of
 gas whatfoever: So that this experiment  turns
 out to be a fimple  diftillation ; and  the refult
 would have been exactly the fame,  if the water
 had  been  run from one veffel  into the other,
without having undergone  the  intermediate in-
candefcence, by paffing through the red hot tube
 EF.
             Experiment Second.

  The apparatus  being difpofed, as in the for-
mer experiment;  38 grs. of charcoal, broken in
to moderately fmall parts, and which has previ-
oufly been expofed for a long  time  to  a red
heat in clofe veffels, are introduced into the tube
                    S 
138          ELEMENTS

EF : Every thing elfe  is managed exactly as in
the preceding experiment.
  The water, contained in the retort A, is diftil-
led,  as in  the  former experiment, and, being
condenfed in the worm SS,  falls into the bottle
H.   But, at the fame time, a confiderable quan-
tity of gas is difengaged, which, efcapihg by the
tube KK,  is received in a convenient apparatus
for that purpofe.  After the operation  is finifh-
ed, we find nothing but a few atoms of afhes re-
maining in the tube EF; the 28 grs. of charcoal
having entirely difappeared.
   When the difengaged gaffes are carefully exa-
mined, they are found to  weigh 113.7 grs-.* ;
thefe are of two kinds, viz. 144 cubical inches
of carbonic acid gas, weighing 100 grs. and 380
cubical inches  of  a Very light gas,  weighing
only 13.7 grs.   This latter  gas  takes fire, when
in contact  with air, by the  approach of a light-
ed body :  and1 when the water, which has paf-
fed over into the bottle H, is carefully examined,
it is found to  have loft 85.7 grs. of its weight.
Hence, in  this experiment,  85.7 grj-.  of water,
joined  to  28 grs.  of charcoal,  have combined
in fuch a way as to form  100 grs. of  carbonic

  * In  th." letter part  cf this work will be fjund  a par-
licuHr  accM'.nt or the proceffes 1 eccflary for  feparati:-^
t!-e different sinds of  gahfts, and for determining  their
quantities,  and the particular nnures of each.—•—T. 
OF  CHEMISTRY
139
acid, and 13.7 grs.  of a particular gas capable
of being burnt.
  I have already fhewn, that 100 grs. of carbo-
nic acid gas confift of  72 grs. of oxygen, com-
bined with 2$ grs. of carbon ; hence the  28 grs.
of charcoal,  placed in the glafs tube, have acqui-
red 72 grs. of oxygen from the water : and it
follows,  that 85.7  grs.  of water are compofed
of 72  grs. of oxygen  combined with 13.7 grs.
of a gas  fufceptible of combuftion.  We  fhall
fee prefently, that  this  gas cannot poffibly have
been difengaged from  the charcoal,  and muft
confequently have  been produced from the wa-
ter.
  I have fuppreffed  fome circumftances in  the
aboye account of this experiment, which would
only have rendered it  complicated,  and made
its refults obfcure to the reader.  For inftance,
the inflammable gas diffolves a very fmall part
of tjie  carbon, by which means its own weight
is  fomewhat augmented, and that of the car-
bonic  gas is  proportionally diminifhed.   Al-
though the  alteration   produced by  this   cir-
cumftance  is  very  considerable.,  yet  I have
thought  it neceffary to  determine its  effects  by
a rigid calculation, and to report, as above,  the
refults of the experiment in its fimplified ftate,
as if this circumftance  had not happened.   At
any rate, fhould any  doubts remain rejecting
the confequences I have drawn from this experi- 
140
ELEMENTS
 ment, they will be fully diffipated by the follow-
 ing experiments, which I am going to adduce in
 fupport of my opinion.

               Experiment Third.

   The apparatus  being difpofed exactly  as  in
 the former experiment, with  this  difference,
 that inftead of the 28 grs. of charcoal, the tube
 EF is  filled with 274 grs. of foft iron, in  thin
 plates, rolled  up  fpirally.   The tube is  made
 red hot by means  of its furnace, and the water,
 in the retort A, is kept  conftantly  boilinog  till
 it be all evaporated, and has paffed through the
 tube E, F, to be condenfed in the bottle H.
   No  carbonic acid is difengaged  in  this  ex-
 periment ; inftead of which  we obtain 416  cu-
 bical  inches,  or  15 grs.  of inflammable   gas,
 thirteen times  lighter*  than  atmofpheric air.
 By examining the water which has been diftil-
 led, it  is found to have  loft 100 grs.  and  the
 zj4grs of iron, confined in the tube, are found
 to have acquired 85 grs. additional weight, and

  * This I conceive to be a very improper exprciTiun.  I
under!!: mil the meaning of one fubftance beinw thirteen
times heavier  thau another ; but I do not underftand how
one can lv  thirteen times lighter.   One  thirteenth of
the weight ofthe heavier would be the proper expreffion
for i.ig !'. ing the  comparative gravity of tie lighter bo-
c'\.----T. 
OF  CHEMISTRY.
141
 its magnitude is confiderably augmented.  The
 iron is now hardly attractable by the magnet. It
 diifolves in acids without effervefcence. In fhort,
 it is converted into a black oxyd, precifely fimi-
 lar to that produced by the combuftion of iron
 in oxygen gas.
   In this experiment we have  a  true oxydation
 of iron by means of water, exactly fimilar  to
 that produced in air by the affiftance of heat.
 One hundred grains of water having been  de-
 compofed,  85 grs. of  oxygen have combined
 with the iron, fo as  to convert it into the ftate
 of black oxyd, and  15 grs. of  a peculiar inflam-
 mable gas  are difengaged.   From  all  this it
 clearly follows, that water is compofed of oxy-
 gen combined with the bafe  of an inflammable
 gas, in the  refpective proportion  of 85 parts,
 by weight, of the former, to 15 parts of the  lat-
 ter.
   Thus water,  befides  the oxygen, which is
 one of its  elements, as it is  of many other fub-
 ftances, contains another element  as  its con-
 ftituent  bafe or radical: and  for this proper
 principle  or  element  we  muft  find  an   ap-
 propriate  term.    None that  we  could think
 of, feemed  better adapted than  the word  hy-
drogen,  which  fignifies  the  generative  prin-
ciple of water, from vUf aqua, and >6„r6/M«, gig- 
142
ELEMENTS
nor*.   We call the combination of this element
with caloric, hydrogen gas ;  and  the term hydro-
gen f expreffes the bafe of that gas, or the radi-
cal  of water.
   This  experiment furnifhes us with  a  new
combuftible body, or,  in other  words,  a body
which has  fo much affinity with  oxygen  as to
draw it from its connection with caloric, and to
decompofe oxygen gas.  This combuftible  bo-
dy has itfelf fo great an affinity with caloric, that,
unlefs  when  engaged  in  a  combination   with
fome other body, it always fubfifts in the aeriform
or gaffeous ftate, in the ufual temperature  and
preffure of our atmofphere.   In  this ftate of gas
it is about -^ of the weight of an  equal bulk of

  * This exprefllon Hydrogen  has been very feverely
criticifed by fome, who pretend that  it (ignifics  engen-
dered by water, and not -that which  engenders  water.
I am not Grecian enougli to fettle the grammatical dif-
pute: but the experiments related in  this chapter prove,
that when water is decompofed, hydrogen is produced,
and  that,  when  hydrogen is combined with  oxygen,
water is produced ; hence we may fay, with -equal truth,
tiiat water is produced from hydrogen,  or  hydrogen is
produced from water.----T.
  j In a former note, it is  mentioned  that this element
appears to be  the bafe of muriatic  acid, and  that, if
the difcovery be autlienric, it might  more  properlv  be
named ?/;?/rio^«.  In this cafe,  what the older chemifts
inmed inflammable air, will become, in the  ne.v no-
menclature, vuiriogen gat; and  water will become  a
real oxyd if ;/r-'ri:~c;i.—— T. 
OF  CHEMISTRY.
*43
atmofpheric air.  It is  not  abforbed by  water,
though it is capable of holding a fmall quantity
of that fluid in folution  : and it is incapable of
being ufed for refpiration, without producing in-
ftant death.
   As the property  of burning, which this gas
poffeffes in common with all other  combuftible
bodies, is  merely the  power  of decompofing
air, and  carrying off its oxygen from the calo-
ric with  which is it combinedj it is eafily  under-
fbood, that it cannot burn, unlefs in contact with
air or oxygen gas.   Hence, when we fet fire to
a bottle full of this gas, it burns gently,  firft at
the neck of the bottle, and then in the infide of
it,  in  proportion as  the external  air gets in.
This combuftion is flow and fucceffive, and on-
ly takes place at the furface of contact between
the two gaffes.   It  is quite  different when the
two gaffes are mixed before they are fet on fire.
If, for inftance,  after having  introduced one
part  of oxygen gas into  a  narrow-mouthed
bottle, we fill it up  with two parts of hydrogen
gas, and  bring a lighted taper, or other  burn-
ing body, to the mouth  of the bottle,  the com-
buftion  of the two gaffes takes place  inftanta-
neoufly  with a violent explofion. This experi-
ment ought only to  be  made in a bottle of very
ftrong  green glafs, holding not more  than a
pint, and ftrongly wrapped round with.twine ;
otherwifj the operator will be expofed to great 
144
ELEMENTS
danger from the rupture of the bottle, of which
the fragments will  be thrown about with great
force.
   If all that  has been related above, concern-
ing the decompofition of water, be exactly con-
formable to  truth—if,  as I have endeavoured
to prove, that fubftance be really compofed of
hydrogen,  as  its  proper  conftituent  element,
combined with oxygen—it ought to follow, that,
by reuniting thefe two elements together, we
fhould recompofe v/ater: and that  this actual-
ly happens, may be judged  of by the following
experiment.

             Experiment Fourth.

  I took a large cryftal balloon, A, PI. IV. fig.5.
holding about 30 pints, having a large  opening
to which  was  cemented  the plate of copper
B C, pierced with four  holes, in which  four
tubes terminate.  The firft tube H h, is in-
tended to be adapted to an  air-pump, by which
the balloon may be exhaufted of its air.  The
fecond tube  gg, communicates,  by its extre-
mity MM, with  a refervoir of  oxygen gas, from
which  the  balloon is to be filled.  The third
tube  d D  d', communicates, by its extremity
d NN, with a refervoir of hydrogen gas.  The
extremity  d' of this  tube terminates  in a ca-
pillary opening, through which the hydrogen 
OF  CHEMIS T R Y.
*45
 gas contained  in the refervoir is forced, with a
 moderate  degree of quicknefs, by the  preffure
 of one or two inches of  water.  The fourth
 tube contains a metallic wire GL, having a knob
 at its extremity h,  intended for giving an elec-
 trical fpark from L to d', on purpofe  to fet fire
 to the hydrogen gas.  This  wire is moveable in
 the  tube,  that we  may be  able  to feparate the
 knob L from the extremity  d' of the tube D d\
 The three tubes, d D d' ^g, andHh, are all pro-
 vided with ftop-cocks.
   That the  hydrogen gas and oxygen gas may
 be as much as  poffible deprived of water, they
 are made to pafs, in  their way to the balloon A,
 through the tubes MM,  NN, of about  an inch
 diameter, and  thefe  are filled with falts, which,
 from their deliquefcent nature,  greedily attract
 the  moifture of  the air:  fuch are the acetite
 of potafh, and the  muriat or nitrat of  lime*.
 Thefe falts muft only be reduced to  a  coarfe
 powder, left they  run  into lumps,   and pre-
 vent the gaffes  from  getting through their inter-
 ftices.
  We muft be provided before  hand  with  a
 fufficient quantity of oxygen gas,  carefully pu-
                      T

  *'See the nature of thefe falts  in  the fecond rare  of
ih'.s^bov'k----A. 
146
ELEMENTS
rified from all  admixture of carbonic  acid, by
long contact with a folution of potafh*.
   We muft likewife have a  quantity of  hydro-
gen gas, equal to  twice the  bulk of the oxygen
gas, and contained in a  feparate refervoir.   This
muft  be carefully purified in the fame manner by
long contact with  a folution of pcrafh in water.
The beft way to obtain this  gas free from  mix-
ture,  is, by decompofmg  water  with  pure foft
iron,  as directed in Exp. 3. of this chapter.
   Having adjufted every  thing properly,  as a-
bove dire&ed, the tube II h is adapted to an air-
pump, and the balloon A is exhaufted of its air.
We next admit the oxygen gas, fo as to fill the
balloon:  and then, by  means of preffure,  as is
before mentioned, force a fmall ftream of hy-
drogen gas, through its tube D d\ to which we
immediately  fet fire,   by  an  electrical fpark.
By means of the above-defcribed apparatus, we
can continue  the  mutual  combuftion  of thefe
two gaffes  for a long time ;  as  we  have the
power of fupplying them,  to the  balloon,  from
their  refervoirs, in proportion  as  they are con-

  * By potafh is  here meant, pure or cauftic vegetable
alkali, deprived of carbonic acid, by means of quick-
lime.  In the general, we may ohferve here,  tint ail the
alkalies and earths mull invariably be  conlidered  as  in
their pure or cauftic ftate,   unlefs otherwife  exprefTed—
T.  The method of obtaining this pure alkali of potafh
will be given in the fequcl.----A. 
        OF  CHEMISTRY.        147

 fumed.  I have in  another place* given  a mi-
 nute defcripdon ofthe apparatus ufed in this ex-
 periment ;  and have explained the manner  of af-
 certaining the quantities of the gaffes confumed
 with the moft fcrupulous exa&itude.
   In proportion  to the  advancement  of the
 combuftion, there is a d:r aftion of water upon
 the  inner furface of the balloon  or  matrafs A.
 The water  gradually increafes in quantity ;  and,
 gathering into  large drops, runs down to the
 bottom of the  veffel.  It is eafy to afcertain
 the  quantity of  water collected, by weighing
 the balloon both before and after  the  experi-
 ment.   Thus we have  a twofold  verification
 of our experiment, by  afcertaining both the
 quantities of the gaffes  employed, and of the
 water formed by their combuftion,  thefe two
 quantities muft  be  equal  to each other.   By
 an operation of  this kind, Mr. Meufnier  and I
 ascertained, that it required 85 parts, by weight,
 of oxygen, united to 15 parts of  hydrogen, to
 compofe one hundred parts of water.  This ex-
periment, which has not  hitherto  been publifh-
ed, was made in prefence of a numerous  com-
mittee  from the  Acalemy of Science.  We ex-
erted,  on that occafion, the moft fcrupulous at-
tention to  accuracy ; and  have  reafon  to be-

       * See the third p-.irt of this wo'i:_____.V. 
148
ELEMENTS
lieve, that the above proportions cannot vary a
two hundredth part from abfolute truth.
   From  thefe experiments,  both analytical and
fynthetic, we may now affirm, that we have as-
certained,  with as much certainty  as is poilible
in phyfical  or  chemical  fubjetts, that  water  is
not a fimple elementary fubftance, but is compo-
fed of two  elements, oxygen and  hydrogen ;
which elements, when exifting feparately, have
fo ftrong an affinity for caloric, as only to  fubfift
under the form of gas in the common tempera-
ture and preffure of our atmofphere.
   This decompofition and recompofition of wa-
ter is perpetually  operating before our  eyes, in
the temperature of the atmofphere,  by means
of compound elective attractions.   We fhall pre-
fently fee,  that the phenomena attendant upon-
vinous fermentation,  putrefa&ion, and  even ve-
getation, are produced,  at leaft in a  certain de-
gree, by the decompofition of water.  It is very
extraordinary, that this fact fhould have hitherto
been  overlooked  by natural philofophers and
chemifts.   Indeed, it ftrongly proves, that,  in
chemiftry,  as  in natural  philofophy, it is ex-
tremely difficult to overcome prejudices imbibed
in early education, and to fearch for truth in any
other road, than the one which we have been ac-
cuftomed to follow.
   I fhall finifh this chapter  with an  account of
an experiment, much lcfj demonftrative indeed 
          OF CHEMJSTRY.       149

 than thofe already related, but which has appear-
 ed to make more impreflion than any other upon
 the  minds  of many.   When  16 ounces  of al-
 kohol  are   burnt  in an apparatus* properly a-
 dapted for   collecting all the water  difengaged
 during  the combuftion, we obtain from  17 to
 18 ounces  of  water.  As no fubftance can fur-
 nifli  a product larger than  its  original bulk, it
 is evident that fomething muft have united with
 the alkohol during  its combuftion :  and I have
 already fhewn that this muft be  oxygen.  Thus
 alkohol contains  hydrogen, which is one of the
, elements of water ;  and the atmofpheric air con-
 tains oxygen, which is the other element neceffa-
 ry to the compofition of waterf.  This  experi-
 ment is a new proof, that water is a compound
 fubftance.


  * See an account of this apparatus in the third part of
 this work----A.

  f A large quantity of carbonic  acid gas is  likew'fe
 difengaged during the combuftion of alkohol ; this pro-
 ceeds from the combination  of carbon, contained along
 with hydrogen in the  compofition of the alkohol,  with
 oxygen during the combuftion. This latter circumftance
 is explained at large in the after parts of this work.—T. 
150
ELEMENTS
               CHAP.  IX.

   Of the Quantities  of Caloric  difengaged during
          different fpecies of Combuftion.


   IT has been already mentioned, that when equal
    quantities of  different bodies are  burnt in
 the centre of a hollow fphere of ice, and  are
 fupplied with  air,  at the temperature of 32°,
 the quantities of  ice melted from the  infide of
 the  fphere,  become  meafures of the  relative
 quantities  of caloric  difengaged during the  fe-
 veral combuftions.   Mr. de la Place and I have
 given a defcription of the apparatus employed for
 this kind of experiment, in the memoirs of the
 Academy  for 1780^.355:  and  a  defcription
 and plate ofthe fame apparatus will  be  found in
 the third part of this work.   With this appara-
 tus,  phofphorus,  charcoal, and hydrogen  gas,
 gave  the following refults.
   One pound of phofphorus melted  100/w.* of
 ice.

  * In the original,  the quantities  refulting  from the
feveral experiments mentioned in this  chnpter, are j?i-
ven in pounds, ounces gros, and grains ;but as the fubject
is curious and interefting, they are  here reduced to de-
cimals of the pound,  by which they become equally ufe-
ful to the Britifh as to the French, reader.----T. 
OF  C FIEMI ST R Y       151
  One pound of charcoal melted 96.5 lbs.
  One pound of hydrogen gas melted 295.5895
lbs.
  As a concrete acid is formed by the combuf-
tion of phofphorus, it is probable, that very little
caloric remains in the acid;  and, confequently,
that  the  above  experiment gives us very nearly
the whole quantity of caloric contained in the
oxvgen gas. Even if we fuppofe the phofphoric
acid to contain a good deal  of  caloric, yet, as
the phofphorus muft have contained nearly an
equal quantity before combuftion, the error muft
be very fmall, as  it will only confift of the dif-
ference  between   what was  contained  in the
phofphorus  before, and in the  phofphoric acid
after combuftion.
   I have already fhown, in Chap.  V. that one
pound of phofphorus  abforbs one pound eight
ounces of oxygen during combuftion : and, fince,
by the fame operation, 100 lbs.  of ice are melt-
ed, it follows, that the quantity of caloric contain-
ed  in  one pound of oxygen gas is capable of
melting 66.666j lbs. of ice.
   One pound  of charcoal during  combuftion
melts  only 96.5  lbs.  of ice, while it abforbs
2.5714 lbs.   of oxygen.  By  the   experiment
with  phofphorus, this quantity  of  oxygen gas
ought  to difengage  a quantity of caloric fuffi-
cient  to melt 171.414 lbs. of'ice:   confequent-
Iv, during this experiment, a quantity  of c.loiac 
I52
E  L E  M E  N T S
fufficient to melt 74,914 lbs. of ice, difappears.
Carbonic acid  is not, like phofphoric acid, in a
concrete ftate,  after combuftion, but in the ftate
of gas ; and requires to be united with caloric to
enable it to fubfift in that ftate :  and the quan-
tity of caloric,  which is miffing in the laft expe-
riment, is evidently employed for that purpofe.
When we  divide that quantity  by the weight
of carbonic acid, formed by the combuftion of
one pound of  charcoal,  we find, that the quan-
tity of caloric, neceffary for  changing one pound
of carbonic acid from the concrete to the gaffeous
ftate, would be capable  of melting 20.9766 lbs.
of ice.
   We may make a fimilar  calculation with the
coraaalica of hyahogen gas and the confequent
formation of water.  During the combuftion of
one pound of hydrogen gas, $.666j lbs. of oxy-
gen gas are abforbed,  and 295.5895 lbs.  of ice
are melted.  But  $.666 j lbs.  of oxygen gas,
in changing from the aeriform to the folid ftate,
lofe, according to the  experiment with phofpho-
rus, enough of caloric to have melted 377-7 ^34
lbs. of ice.  There is only difengaged, from the
fame  quantity of oxygen,  during its combuf-
tion with hydrogen gas, as much caloric as melts
295.1523//a\ ; wherefore there remains in the
water at 320,  which is  formed, during this ex-
periment, a-i much caloric aj would melt 82.6211
lbs. of ice. 
          OF   CHEMISTRY.         153

   Hence, as 6.M6j lbs.  of v/ater are formed,
 from the combuftion of one pound of hydrogen
 gas,  with $.666j  lbs. of  oxygen;  it  follows
 that, in  each pound of  water, at the tempera-
 tare of 320,  there  exifts  as  much  caloric  as
 would melt 12.2708 lbs.  of ice ;  without  taking
 into account the  quantity  originally contained
 in the hydrogen gas, which we have been ob-
 liged to omit,  for want of  data to calculate  its
 quantity*.   From  this  it appears, that water,
even i:i the ftate of  ice, contains  a  confidera-
   * From the general principles  of the  new  chemical
 philofophy,  Hydrogen gas ought to contain a much lar-
 ger quantity of caloric forgiving  it  the  gafleous  ftate
 than oxygen gas.  Being thirteen times r.s rare, it  may
 be fuppofed  to contain thirteen times as  much caloric.
 leence, if all the caloric ofthe two gafles were difenga-
 ged during their combuftion, and the confequent forma-
 tion of water, 1244.4167 lbs. of ice fhould  have  been
 melted.  But only 295.1522 lbs.  rre melted, and there.
 fore, on this fuppofition, the remaining caloric,in 6.6667.
 /«/.  of water, would be able to melt 94.92643//?/.  \ce\
 or eacli  pound  of water, at  the  temperature of 320,
 flioul.l centain as much caloric as is fufficient  to  melt
 142 lbs. of iee nearly,  which is abfurd ; for  one pourd
 of water, at  320,  muft contain precifely as much caloric
 as is neceftary to melt one pound of ice.  This fiiews the
 fallacy  of reafor.ings drawn from the fuppofable quanti-
 ties of caloric in  bodies ; and that  we are  hitherto
 very far from pofleffing any accurate  knowledge  o! that
part  of chemiftry in which caloric is concerned.---■ T.
                         V 
'54
ELEMENTS
ble quantity of caloric,  and that oxygen,  in en-
tering  into the  combination,  retains likewife a
good proportion.
   From thefe experiments, we may affume the
following refults as fufficiently eftablifned.

           Combuftion ef Phofphorus.

   From the combuftion of phofphorus, as rela-
ted in the foregoing experiments, it appears, that
one pound of phofphorus requires  1.5 lb. of oxy-
gen gas for its combuftion ;  and that 2.5 lbs. of
concrete phofphoric acid are produced.
The quantity of caloric difengaged by
   the combuftion  of one pound  of
   phofphorus, expreffed by the num-
   ber of pounds  of ice melted du-
   ring that operation, is            100.00000
The quantity difengaged  from each
   pound of oxygen, during the com-
   buftion of phofphorus, expreffed in
   the fame manner, is               66.66667
The quantity difengaged during the
   formation of one pound of phof-
   phoric acid, is                    40.00000
The quantity remaining in each pound
   of  phofphoric acid, is*             0.00000

  * Vehere fuppofe ihe pV fphoricacid not tocontain any
caloric, which is n<,z ftrictly true ; but, as I have before 
OF  CHEMISTRY.
l55
              Combuftion of Charcoal.

    In the combuftion of one pound of charcoal,
  2.5714/fo. of oxygen gas  are  abforbed,  and
  3.571 4 lbs. of carbonic acid gas are formed:
  Hence the
  Caloric difengaged during the combuf-
    tion of one pound of charcoal*    96.50000
  Caloric difengaged during the combuf-
    tion  of  charcoal, from each pound
    of oxygen gas  abforbed,           37-5-82t
  Caloric  difengaged durhi:? the forma-
    tion of one pound of carbonic acid
    Sas>                              27.02024
  Caloric retained by each pound of oxy-
    gen after combuftion,              29.13844
  Caloric  neceffary  for fupporting one
    pound of carbonic acid in the ftate
    °f gas>                           20.97960

          Combuftion  of Hydrogen Gas.

    In the combuftion of  one pound of hydrogen
 gas,  5.666^  lbs.  of  oxygen  gas  are  abforbed,

obferved,  the  quantity it really contains is probably ve-
ry fmall :  and we have not gi.  .; it a value, for  want of
fufficient data to go upon----A.
  * All thefe  relative quantities of caioric p.re exprelTed
by the number of pounds of ice, nrd decimal  parts, mel-
ted during the feveral operations.----T. 
156
ELEMENTS
and 6.666y  lbs. of  water are formed :  Hence
the
Caloric difengaged from each lb.  of
  hydrogen gas*,                   295.58950
Caloric difengaged from  each  lb.  of
  oxygen gas,          -            52.16280
Caloric difengaged during the forma-
  tion of each pound of water,       44.33840
Caloric retained by each lb.  of oxy-
  gen after combuftion with hydro-
  gen,       -        -        -      -14.50386
Caloric retained by  each lb. of wa-
  ter, at the temperature of 3 4 °,      12.32823

        Of the Formation of Nitric Acid.

  "When nitrous gas is  combined with  oxygen
gas, fo as to form  nitric or nitrous  acid, a  de-
gree of  heat  is produced,  which is much  lefs
confiderable  than what is evolved  during  the
other combinations!, of  oxygen ;  whence it  fol-
lows, that  oxygen,  when it becomes  fixed in
nitric  acid, retains  a  great part of  the heat

  * We are no where told upon what data Mr.  Lavoi-
fier proceeds for afcertaining the quantity of caloric dif-
engaged during  the combuftion of each  pound  of hydro-
gen gas.  In a  former  note, I  have fuppofed, that it
might be thirteen times as much as that cf water: hence
it wculd be 6^3.1164, inftead ofthe  above  number.—T. 
OF  CHEMISTRY.
l57 ~
which it poffeffed in the ftate of gas.   It is cer-
tainly poffible to determine the quantity of calo-
ric which is disengaged during the combination
of thefe two gaffes, and  confequently to deter-
mine what quantity remains after the combina-
tion takes place.   The firft of thefe  quantities
might be afcertained, by making the combination
of the two gaffes in an apparatus furrounded by
ice.   But, as the quautitv of caloric difensrap-ed
is very inconfiderable, it would be  neceffary to
operate upon a large quantity of the two gaffes,
and in a very troublefome and complicated appa«
ratus.  By this  confideration,  Mr  de la Place
and  I have hitherto  been prevented from ma-
king  the attempt.   In the mean time, the place
of fuch  an  experiment may be fupplied by cal-
culations, the  refults  of which cannot  be very
far from truth.
   Mr de la Place and  I deflagrated a convenient
quantity of nitre and charcoal in an ice apparatus,
and found that twelve pounds of ice were melted
by the deflagration of one pound of nitre.   We
fhall fee, in the fequel, that one pound of nitre
is compofed, as under, of

Potafh   7 oz. 6^0^.51.84^. = 4515.84 «tj.
Dry acid 8    1      21.16    =4700.16.

   The above  quantity of dry acid is  compofed
of, 
 I58          ELEMENTS

 Oxygen 6 oz. 3 gros 66.34 grs. = 3738.34^;-;.
 Azot    1    5     25.82     =  961.82

   By this we find that, during the above defla-
 gration,  145-i- grs. of carbon*  have  frffercd
 combuftion, along with 3738.34 grs. or 6 oz.  3
gros 66.34 grs. of oxygen. Hence, fince 12  lbs.
 of ice were melted during the combuftion, it  fol-
 lows, that one pound of oxygen,  burnt in the
 fame  manner, would  have melted 29.5832  lbs.
 of ice.   To which if we  add  the  quantity  of
 caloric  retained by a pound of  oxygen, after
 combining with carbon to form  carbonic  acid
 gas, which was already afcertained to be capable
 of melting 29.13844  lbs.  of  ice,  we fhall have
 for the  total  quantity of caloric remaining in  a
 pound  of oxygen, when combined wkh nitrous
 gas in  the nitric acid,  58.72164; which is the
 number of pounds of ice the caloric remaining in
 the oxygen in that ftate is capable of melting.
   We have before feen, that, in the ftate of oxy-
 gen gas, it contained at leaft  66.6666y ; where-
 fore it  follows that,  in combining with azot to
 form nitric acid, it only lofes 7.94502.   Farther

  * From this it appears, that the proportions ufed by
 Mr Lavoifier were  1 lb.  org2i6 "rs. of n'rreto 2 gros
li grs. or 145.24 irs. of  charcoal, though he has not
chofen to mention it in direct terms----T. 
OF  CHEMISTRY.
*J9
experiments upon this fubjett are neceffary to af-
certain how far the refults of this calculation
may agree with direct, fact.   This  enormous
quantity of caloric, retained by  oxygen in its
combination into nitric acid, explains the caufe
ofthe great difengagement of caloric during the
deflagrations of nitre :  or, more ftriclly fpeaking,
upon all occafions of the decompofition of nitric
acid.

           Of the Combuftion of Wax.

  Having examined feveral  cafes of fimple com-
buftion, I mean now to give a few examples of
a more complex nature.   One  pound of wax-
taper being allowed to burn flowly in an ice ap-
paratus, melted i^T,.i66y lbs. of  ice.  Accord-
ing to my experiments, as given in the memoirs
of the Academy for 1784, p. 606, one pound of
wax-taper confifts of 0.8228 lbs. of carbon, and
0.1772 lbs. of hydrogen.

  By the foregoing experi-
ments, the above  quantity
t f carbon ought to melt,  79-39390 lbs.  of ice;
  And the hydrogen
fhould melt              52'376c$
In all 131.76095 lbs. 
i6o
ELEMENTS
   Thus, we fee  that  the  quantity of  caloric
difengaged  from a  burning taper,  is nearly
conformable to what was obtained by  burning
feparately a quantity of carbon  and hydrogen
equal to what enters into its compofition. Thefe
experiments with the taper  were feveral times
repeated, fo  that I have reafon to believe them
accurate.

           Combuftion  of Olive Oil.

   We included a burning lamp, containing a
determinate  quantity of olive oil, in the ordi-
nary  apparatus ;  and,  when  the experiment
was finifhed,  we  afcertained exa&ly  the  quan-
tities of oil confumed,  and of  ice melted ;  the
refult was, that, during the combuftion of one
pound of olive oil,  148.8828  lbs. of ice were
melted.   By  my experiments,  in the Memoirs.
of the Academy for  1784,  and of whieh  the
following chapter contains an abftraft, it appears
that one pound of olive oil  confifts of  0.7896
lbs. of  carbon, and  0.2104 lbs. of hydrogen.
By the  foregoing experiments, that  quantity
of carbon fhould melt  76.18723  lbs.  of ice:
and the  quantity  of  hydrogen, in a pound  of
the oil,  fhould melt 62.15053 lbs.  The firm of
thefe  two  gives 133.33776 lbs.  of  ice, which
the two conftituent  elements of the oil would
have melted,  had they  feparately fuffered com- 
         OF  CHEMISTRY.       161

 buftion:  whereas  the  oil had  really  melted
 148.88330 lbs. which gives an excefsof 10.54544
 in the  refult of the experiment, above  the  cal-
 culated refult,  from  data furnifhed by former
 experiments.
   This difference, which is by no means very
 confiderable, may arife from errors  which are
 unavoidable in experiments  of this nature, or
 it may be owing to the compofition  of oil  not
 being  as  yet  exactly  afecrtained.   It proves,
 however, that there is a great agreement between
 the  refults cf  our experiments,  reflecting the
 combination  of caloric, and thofe which regard
 its difeno-a^ement.
   The  following  desiderata  ftill remain to be
 determined';  vin.  What  quantity of caloric is
 retained by oxvgen, after combining with me-
 tals to  convert them into oxyds?  What quanti-
 ty is contain 2d by  hydrogen, in its  cii-Ierent
 ftates of exiftence ? and,  To afcertain, with more
 precifion than  is  hitherto attained, how much
 caloric  is difengaged during the formation of
 water ; as there ftill remain confiderable doubts
 with refpect to our prefent determination of this
 point,  which can  only  be removed  by farther
 experiments.   We are at prefent occupied with
 this  inquiry :  and, when thefe feveral  points
 are weil afecrtained, which we hope  they will
foon be, we fnall probably be under the necef-
fity  of  making  confiderable corrections  upon 
I 62
ELEMENTS
moft of the refults  of the experiments and cal-
culations  in this  chapter.  I did not, however,
confider this as a  fufficient reafon for with-hold-
ing fo much as is already known, from fuch as
may be inclined to labour upon the fame fubject.
It is difficult, in our endeavours to difcover  the
principles of  a new fcience, to avoid beginning
by conje&ure :  and it  is  rarely poffible to attain
perfe&ion at the firft fetting out. 
OF  CHEMISTRY       163
               C  II  A P.   X.

 Ofthe Combinations of Combuftible  Subftances with
                  each ether.


      AS combuftible fubftances  in general  have
       great affinity for oxygen,  they  ought
 likewife to attradl, or tend  to combine  with,
 each other ;  Quce funt eadem uni  tertio,funt  ea-
 dem inter J e;  and the  axiom  is found  to be
 true.   Almoft all  the metals,  for inftance,  are
 capable of uniting  with each  other,  and of
 forming what are  called alloys* in  common
 language.   Moft of thefe,  like  other chemical
 combinations,  are fufceptible of feveral degrees
 of faturation.  The greater  number  of alloys
 are more brittle than the pure metals of which
 they are compofed, efpecially when the metals
 alloyed  together  are confiderably different in

  * This term alloy, which we have from the language
of the arts,  ferves exceedingly well for  dillinguifhing
all the combinations or intimate unions of metals with
euch other, and is adipted in our new  nomenclature for
 that purpofe----A. 
E  L E M E.N  T S
 their degrees  of fufibility.  To this  diiTercnce
 in fufibility,  part ofthe  phenomena attendant
 upon  alloyage  are   owing;  particularly that
 property of  iron, called  by workmen hotjhort.
 This kind  of iron muft be confidered as an al-
 loy, or mixture of pure iron, which is almoft in-
 fufible, with  a fmall portion of fome other me-
 tal,  which fufes in a  mucl\ lower degree of heat:
 So long as this  alloy  remains cold,  and both me-
 tals  are in the  folic! ftate, the mixture is  mal-
 leable ; but  when heated to a fufficient  degree
 to iiquefy the more  fufible metal, the particles
 of this  liquid metal, which  are interpofed be-
 tween   the particles of the folid iron, muft de-
 ftroy their continuity, and occafion the  alloy io
 become brittle.  The alloys of mercury, with the
 other metals, have ufually been called amalgams :
 and we fee no- inconvenience  from  continuino-
                                           o
 the ufe of that term.
  Sulphur, phofphorus, and carbon, readily u-
 nke  with  metals.   Combinations of  fulphur
 with metals  are ufually named  pyrites.  Their
 combinations with  phofphorus  and carbon are
 either not  yet  named, or have received  new
 names  only  of late : wherefore we have not
fcrupled to   change   them according  to  our
 principles.   The  co?nbinations  of  metal  and
fulphur we  call fulphurets ;  thofe formed with
phofphorus pari buret:, and thofe  with carbon 
OF   CHE M I S T R Y.
165
 carburets*.   Thefe  denominations are  extend-
 ed to all the  combinations into which the above
 three fubftances enter, without  being previouf-
 ly oxygenated.   Thus, the  combination of ful-
 phur with potafli, or  fixed vegetable alkali, is
 called fulphuret  of potafh ;  that which it forms
 with  ammoniac, or volatile  alkali, is termed ful-
 phuret of ammoniac.
    Iivdro'-en  is  likewife capable of  combining
 with many combuftible fubftances.   In the ftate
 of gas,  it diffolves carbon, fulphur, phofphorus,
 and feveral metals. We diftinguifh thefe combi-
 nations by  the  terms, carbonated hydrogen gas,
 fidphurated  hydrogen gas, and phofphcrated hy-
 drogen gas.   The fulphurated hydrogen gas was
 called hepatic air by former chemifts ; or foetid
 air from fulphur,  by Mr Scheele.  The virtues
 of feveral  mineral waters, and  the  foetid fmell
 of animal excrements,  chiefly arife from the pre-
 fence of this gas.   The phofphorated  hydrogen
 gas is  remarkable for  the property,  difcovered

   * In the French mmridunr', thdV compounds are
 mme&f.lplurcs, pbnfplvr-is, and carburet ;  bet. though
 thefe  terms may be fjfficiently diP.inp.uifliahle fr^m fouf-
fre, phofp'ror:,  and carbine, they are rot, efpeually the
 two Srfl:,  diftiDci enough i-i Lr.;;!im.  I have therefore
 chofen to borrow  the new Englifii teir.n  in the text
 from the  Latin edit'vi of the new nomenclature, v. here
 they are cal'rd r.-furtively Julphur.tinm, pho().h,jrett:iv:,
 and carburatu,;!—T. 
166          ELEMENTS
 by Mr Gengembrc, of taking fire fpontaneouily
 upon getting into contad with atmofpheric air,
 or,  what  anfwers  better, with  oxygen  gas:
 This gas has a  ftrong  flavour, refembling that
 of putrid fifh:  and it is very probable  that the
 phofphorefcent  quality  of fifh, in  the ftate of
 putrefaction, arifes  from the efcape of this fpe-
 cies of gas.   When hydrogen and  carbon are
 combined together,  without   the intervention
 of caloric to  bring  the hydrogen  into the  ftate
 of gas,  they form oil, which is either fixed or
 volatile, according to the proportions of hydro-
 gen  and carbon in its  compofition *.    The
 chief difference between  fixed or fat oils  drawn
 from vegetables  by  expreffion,  and volatile or
 effential oils,  is,  that the  former contains an ex-
 cefs  of  carbon,  which  is  feparated  when  the
 oils are  heated  above  the  degree  of boiling
 water;  whereas  the volatile  oils,  containing
 a  juft proportion of thefe  two conftituent in-
 gredients, are not liable  to be decompofed by
 that  heat, but,  uniting  with caloric  into the
 gaffeous  ftate, pafs over  in diftillation unchan-
 ged.

  * We flnll afterwards fee, that oil contains oxygen,
combined with the abovementioned ingredients, and that
it is a  hydroc.;rbonous  or carbono-hydrous oxyd ;  hence
the difference between the various kinds may in p?rt be
owing to their different degrees  of o>:yda:ion, as well
as to the proportions of the other ingredient*.----T. 
         OF  CHEMISTRY.       167

   In  the  Memoirs of the Academy for  1784,
 P- 593>  1  Save an account of my experiments
 upon  the  compofition of oil  and  alkohol, by
 the  union of  hydrogen  with carbon,  and  of
 their  combination  with  oxygen.   By  thefe
 experiments, it appears,  that fixed  oils  com-
 bine with  oxygen during combuftion,  and are
 thereby  converted into water and carbonic  a-
 cid.   By means of  calculation, applied to the
 products of thefe experiments,  we find that fix-
 ed oil is compofed of 21 parts, by weight, of
 hydrogen,  combined with 79  parts of  carbon.
 Perhaps  the  folid fubftance of an oily nature,
 fuch as wax, contain a proportion of oxygen,
 to which they   owe their ftate  of folidity.  I
 am at pr-lent  engaged  in a  fcries of experi-
 ments, which,  I hope, will throw great light on
 tin 5 fubjed.
   It is worthy of being examined, whether hy-
 drogen in  its concrete ftate, uncombined  with
 caloric,  be fufceptible  of combination  with
 fulphur,  phofphorus,  and the  metal j.  There
 is  nothing  that  we know of,  whieh, a priori,
 mould render thefe  combinations  impomble;
 for combuftible  bodies being   in  pa-era'  fuf-
 ceptible of  combination with each other, there
 is  no   evident  reafon for hydrogen beknr an
 exception to the rule.   However,  no direct ex-
periment  as yet eftablifhes ci-hcr the  ooffibi-
lity or impoffibility of this union,   fron  end 
 168          ELEMENTS

zinc are the  moft likely, of all the metals,  for
entering into combination with hydrogen.  But,
as  thefe  have the  property of  decompofing
water, and as it  is very difficult  to get entirely
free from moifture  in  chemical  experiments,
it  is hardly poffible  to determine whether  the
fmall  portions of hydrogen gas,  obtained  in
certahi experiments  with  thefe  metals,  were
previoufly combined with  the mend  in   the
ftate of folid hydrogen, or if they  were pro-
duced by the decompofition of  a  minute quan-
tity of water.  The  more care  we take to pre-
vent the  prefence of  water in  thefe  experi-
ments, the lefs is the quantity of  hydrogen gas~
pea iv, ;  and v. hen very accurate precautions
are employed, even that quantity b -comes hardly
fcnnble.
   However thie inquiry may turn out,  refpect-
iim- the power of combuftible  bodies,  as  fui-
pl-nw,  uhofphorus, and  metals, to  abforb hy-
dro-en, we are certain  that they  only abforb a
very fmall nortion ;  end that this combination,
inftead ^f being  efiea'h .1 to their  conftitution,
can only  be confidered  a;  a foreign fubftance,
which  contaminates  their  purity.   It  is  the
province of  Lie  advocates* for this  fyftem,  to

 * Y'-\  ;'ie'e arc msant rh^O. fuppcrters of th» ph'ogiflic
theory,  who conhc' > hydrogen,  or the b.Ue  «f inflan.:");-
l..h. *ir, es the  phhm^on oithe  ct-Lbrated b:ahl.----T- 
OF  CHEMISTRY.        169
prove  by decifive  experiments, the real exift-
ence of this  combined  hydrogen, which they
have hitherto only done by conjectures founded
upon fuppofitions. 
170
ELEMENTS
       '     CHAP  XL

Obfervations upon  Oxyds and Acids  with com-
  pound Bafes—and on the Compofition of Animal
  and Vegetable fubftances.


      E have, in  Chap V. and VIII. examined
       the produ&s refulting from the combuf-
tion of the four fimple combuftible fubftances,
fulphur, phofphorus, carbon, and hydrogen. We
have fhewn, in Chap. X. that the fimple combuf-
tible fubftances are capable of combining with
each other into compound combuftible  fubftan-
ces ; and have obferved, that oils in general, and
particularly the fixed vegetable oils, belong to
this clafs, being compofed  of hydrogen and car-
bon.  It remains, in this chapter, to treat of the
oxygenation of thefe compound combuftible fub-
ftances, and to fhow, that there exift acids and
oxyds having double and triple bafes.   Nature
furnifhes us with numerous  examples of this
kind of combinations, by means of which, chief-
ly, foe is enabled  to  produce  a vaft variety of
compounds, from a very limited number of ele-
ments, or fimple fubftances.
w 
OF  CHEMISTRY.
x7*
   It was long ago well known, that, when mu-
 riatic and  nitric  acids  were mixed together, a
 compound acid was formed,  having properties
 quite diftinct from thofe of either  of the acids
 taken  feparately.   This acid was called aqua
 rcgia, from its  moft celebrated  property of dif-
 folving gold, called king of metals by the alchy-
 mifts.   Mr Berthollet has diftinctly proved, that
 the peculiar properties of this acid arife from the
 combined action of its two acidifiable bafes: and,
 for this reafon, we have judged it neceffary to dif-
 tinguifh it by an appropriate name : that of nitro-
 muriatic acid  appears extremely applicable, from
 its expreffing the nature of the two fubftances
 which enter into its compofition.
   This phenomenon, of a double bafe in one
 acid, which had formerly been obferved only in
 the  nitro-muriatic acid, occurs   continually  in
 the vegetable kingdom;  in which a fimple acid,
 or one poffeffed of a fingle acidifiable  bafe, is
 very rarely found.   Almoft all the acids pro-
 curable from this  kingdom,  have bafes  com-
 pofed of carbon and  hydrogen, or of  carbon,
 hydrogen, and phofphorus, combined with more
 or lefs oxygen.   All  thefe bafes,  whether dou-
 ble or triple, are  likewife formed into oxyds,
 having  lefs oxygen  than is  neceffary  to give
 them the properties of acids.   The acids and
oxyds  from  the animal kingdom, are ftill more
 compound, as their  bafes generally confift of a 
IJ2.
ELEMENTS
combination of carbon,  phofphorus,  hydrogen,
and azot.
   As it is but of late that I have acquired any
clear and  diftinct notions of thefe fubftances,  I
fhall not, in this place,  enlarge much upon the
fubjett, which I mean to treat of very fully in
fome memoirs I am preparing to lay before the
Academy.  Moft of my experiments are alrea-
dy performed.  But, to be able  to  give  exaft
reports ofthe refulting  quantities, it is neceffary
that they be carefully repeated, and  increafed
in number : wherefore, I  fhall  only give a fhort
enumeration of the vegetable and animal acids
and oxyds, and terminate this article by a few re-
flections  upon the compofition of vegetable and
animal bodies.
   Sugar, mucus, under which term we include
the  different kinds of gums, and ftarch, are ve-
getable oxyds, having hydrogen and carbon com-
bined, in different proportions, as their radicals or
bafes, and  united  with  oxygen, fo as to bring
 them to the ftate of oxyds.  From this ftate of
 oxyds, they  are capable of being changed into
 acids, by the addition of a frefh quantity of oxy-
 gen : and,  according to the degrees  of oxygena-
 tion, and the proportion of hydrogen and car-
 bon in their  bafes, they form the feveral kinds
 of vegetable acids.
   It would be eafy to   apply  the principles  of
 our nomenclature to give names to thefe vege- 
OF  CHEMISTRY
table acids and oxyds, by ufing the names of
the two fubftances  which compofe their bafes :
They would  thus  become  hydro-carbonous a-
cids  and oxyds.  In this way we might indicate
which of  their elements exifte J in excefs, with-
out  circumlocution,  after the manner ufed by
Mr  Rouelle for naming the vegetable extra£ts:
He calls thefe extracto-refinous, when the ex-
tractive matter prevails  in  their compofition,
and  refino-extractive,  when  they   contain a
larger proportion of  refinous matter.   Follow-
ing that plan,  and by varying the terminations
according to the formerly  eftablifhed  rules of
our nomenclature, we have the following  deno-
minations  :  Hydro-carbonous,  hydro-carbonic
carbono-hydrous, and  carbono-hydric,  oxyds.
And, for the acids :  Hydro-carbonous,  hydro-
carbonic, oxygenated hydro-carbonic :  carbono-
hydrous, carbono-hydric, and oxygenated carbo-
no-hydric.
   It is probable, that  the above terms would
fuffice for indicating all the varieties in nature,
and  that,  in proportion as the vegetable acids
become well  underftood, they will naturally
arrange themfelves  under  thefe denominations.
But,  though we know the  elements of which
thefe are  compofed,  we are as yet ignorant of
the proportions of thefe ingredients, and are ftill
far from being able to clafs them in the above
methodical manner;  wherefore,  we have de- 
174          ELEMENTS

termined to retain  the old names provifionally.
I am  fomewhat farther advanced in this inqui-
ry than at the time of publifhing our conjunct
effay upon chemical nomenclature :  yet it would
be improper to draw decided confequences from
experiments not yet fufficiently precife. Though
I acknowledge that this  part of chemiftry ftill
remains in fome degree obfcure,  I muft exprefs
my expectations of its being very foon elucida-
ted.
  I am ftill more forcibly neceffitated to follow
the fame plan in naming the acids,  which have
three  or  four elements combined in their bafes.
Of thefe we have a confiderable number from
the animal kingdom,  and fome even  from ve-
getable fubftances.   Azot,  for inftance, joined
to hydrogen and carbon,  form the bafe or radi-
cal of the Pruffic acid.   We have reafon to be-
lieve that  the fame happens with  the bafe of
Gallic acid ;   and almoft all the animal acids
have their bafes compofed of azot,  phofphorus,
hydrogen, and carbon.   Were we to endeavour
to exprefs at once all thefe  four  component
parts  of the bafes,  our nomenclature would un-
doubtedly  be  methodical.   It would  have the
property of being clear and determinate.  But
this affe.nblage of  Greek and Latin  fubftantives
and  adjectives, which are  not  yet univerfally
admitted by chemifts,  would have  the appear-
ance  of a barbarous language,  difficult both to 
         OF CHEMISTRY.       175

pronounce and  to be remembered.   Befides,
this part of chemiftry  being ftill far from that
accuracy it muft foon attain, the perfection  of
the fcience ought  certainly to precede that of
its  language;  and  we muft ftill,  for  fome
time,  retain  the  old  names  for  the animal
oxyds and acids.   We have  only  ventured to
make a few flight  modifications of thefe names,
by changing the termination into  ous, when we
have  reafon to fuppofe the bafe to be in excefs,
and into ic, when  we fufpect  that oxygen pre-
dominates.
   The following are all the vegetable acids hi-
therto known :

i. Acetous acid.         8. Pyro-mucous  acid.
2. Acetic acid.           9. Pyro-lignous acid.
3. Oxalic acid.          10. Gallic acid.
4. Tartarous acid.       11. Benzoic acid.
5. Pyro-tartarous acid.   12. Camphoric acid.
6. Citric acid.          13. Succinic acid.
7. Malic acid.

   Though all thefe acids,  as has been already
faid, are chiefly, and almoft entirely,  compofed
of hydrogen,  carbon, and oxygen ;  yet, proper-
ly fpeaking, they contain neither  water, carbo-
nic acid, nor oil, but only the elements neceffa-
ry for  forming thefe  fubftances.  The  power
of affinity reciprocally exerted by the hydrogen,
carbon, and oxygen, in thefe acids, is in a ftate 
176          E  L E M E  NTS

of equilibrium, which is only capable of exifting
in the ordinary temperature of  the atmofphere.
For, when they  are  heated but a  very little a-
bove the temperature of boiling water,  this equi-
librium is deftroyed ;  part of the oxygen and hy-
drogen unite, and form water ;  part of the car-
bon and hydrogen combine into oil;  part of the
carbon and oxygen unite to form carbonic acid ;
and, laftly, there generally remains a fmall  por-
tion of carbon, which, being in  excefs with re-
fpeCt  to  the other  ingredients,  is left free.   I
mean to explain this  fubj ect fomewhat further in
the fucceeding chapter.
   The oxyds of the animal kingdom are hitherto
lefs known than thofe from the vegetable king-
dom ; and their number as yet is not at all deter-
mined.  The red part of the blood, lymph, and
moft of  the fecretions,  are  true  oxyds,  under
which point of view it is very  important to confi-
der them.   "We are only acquainted with fix ani-
mal acids, feveral of which, it  is probable, ap-
proach very near each other in their nature,  or,
at leaft,  differ only in a fcarcely fenfible degree.
I do not include the phofphoric acid amongft
thefe, becaufe  it  is found in all the kingdoms of
nature.   They are,

i. Lactic acid.         4. Formic acid.
2. Saccho-lachie acid,   5. Sebacic acid.
3. Bombic acid.        6. Pruffie acid. 
OF  CHEMISTRY.
177
   The  connection between the conftituent ele-
ments  of the animal oxyds and  acids  is  not
more permanent  than in thofe from the vege-
table kingdom ;  as a fmall increafe of tempera-
ture is fufficient to overturn the equilibrium.   I
hope to render this fubject more diftinct in  the
following chapter than has been done hitherto.
Z 
178
ELEMENTS
             C H  A  P.  XII.


Of  the Decompofition  of Vegetable and Animal
        Subftances  by the A alien cf Fire. '


    EFORE we  can thoroughly  comprehend
      what takes place  during the decompofi-
tion of vegetable  fubftances  by fire,  we  muft
take into confederation  the nature  of the ele-
ments which enter  into  their compofition,  and
the different  afinities which   the  particles of
thefe  elements exert upon each other, and the
affinity  which  caloric  poffeffes  with  each of
them.   The true conftituent  elements of vege-
tables  are  hydrogen,   oxygen,  and  carbon.
Thefe are common  to  all vegetables ; and no 0
vegetable  can exift without them.   Such other
fubftances as  exit  in particular vegetables, are
only effential to the compofition of thofe in which
they are found ; and do not b-doug to vegetables
in general.
   Of  thefe  elements,  hydrogen  and oxygen
have a  ftrong tendency  to unite with caloric,
and be convened into gas; while  carbon is  a
fixed element,  having liule affinity with  calo-
ric.  On the other hand, oxygen, whieh, in the
ufual temperature,  tends a: mo ft equally to  unite 
QF  CHEMISTRY.
179
 with hydrogen  or with  carbon,  has  a much
 ftronger affinity  with  carbon, when  at  the red
 heat*,  and then  unites with it to form carbonic
 acid.
    Although we   are far from being able to ap-
 preciate all thefe powers of affinity, or to exprefs
 their proportional energy by numbers, we are
 certain, that, however variable they  may  be,
 when  confidered  in  relation to the quantity of
 caloric  with  which they are  combined, they  are
 all nearly  in equilibrium in  the ufual  tempera-
 ture of the atmofphere.   Hence vegetables nei-
 ther  contain oilf,  water,  nor carbonic acid,
 though they contain  ail the elements  of thefe
 fubftances.   The  hydrogen is not  combined
 particularly with the oxygen, nor with  the car-

  * Though  this term, red bear, docs no" indicate anv
abf)l.!tely determinate degree of temper.uure, I fiiall uis
it for.ciimcs to exrrcf-; a te-.-rerature confiderably above
that of b.iiiir:^  water.----A.
  j I muft be nnderftool here to fpeak of vegetables re-
duced to a perfectly dry ft ite ; and, with refpect to oil,
I do not mean that whLh  is procured by  exprefiion ei-
ther in tlis cold, or in a temperature r.ot exceeding rim*:
of boiling wat?r. I only allude to the empyreuKuab: oil,
nrocured  by diftiliuion wiih a naked fire, in  h^at fupe-
rior to the temperature of bo'llna; water; which is  tiie
only oil declared to be produced by the operation of fire,
What I have puMifiecl upon ibis fubject,  in the Memoirs
ofthe Academy for J7v% m;>y  b? consulted,—— -A. 
i8o
ELEMENTS
bon ; and, reciprocally, the particles  of tliefs
three fubftances  form a  triple   combination,
which remains in equilibrium, while undifturb-
ed by caloric ; but a very flight increafe of tem-
perature is fufficient to overturn this ftru&ure of
combination.
  If the  increafed temperature,  to which the
vegetable is expofed, does not exceed the heat of
boiling water, one  part of the hydrogen com-
bines with the oxygen,  and forms water ;  the
reft  of the  hydrogen  combines with a part of
the  carbon, and forms volatile oil;  while the
remainder of the carbon, being fet free from its
combination with the other elements*, remains
fixed in the bottom ofthe diftilling veffel.
  When, on the contrary,  we  employ  a red
heat, no water is formed ;  or, at leaft, any that
may have been produced,  by the firft  applica-
tion  of the  heat, is decompofed ; the oxygen,
having  a greater  affinity  with  the carbon at
this  degree  of  heat, combines with  it to form
carbonic  acid;  and the hydrogen,  being left
free from combination  with the  other elements,
unites with  caloric, and efcapes in the ftate of

  * This ftatement is only partially true;  for  a  fmall
r:irt ofthe ingredients remains very obftinatelv attached
to :ii2 carbon, and can hardly be driven from it without
rbe aalaa-H -e of oxygen, by  means of which  the carbon
iifrlf fuffers coT.b::(lion.—T. 
OF
C IIEMISTR Y.
181
  hydrogen gas*.   In this high  temperature, ei-
  ther no oil is formed, or if any has been produced
  during the lower temperature, at the beginning
  of thz experiment, it is decompofed by the ac-
  tion of the  red heat.   Thus the decompofition
  of vegetable matter, under a high temperature,
  is produced by the aftion of double and triple
  affinities ; while the carbon  attrafts the  oxygen,
  on purpofe to form carbonic acid, the caloric at-
  tracts the hydrogen, and converts it into hydro-
  gen gas.
   The diftillation of every  fpecies of vegetable
 fubftance  confirms  the  truth of this theory, if
 we can give that name to a fimple relation of
 fc&s.   When fugar is fubmitted to diftillation,
 fo long as we only employ a heat but a little
 below  that  of boiling water, it only lofes its
 water of cryftallization ;  it  ftill  remains fugar,
 and retains all  its properties.  But, immediately
 upon raifing  the  heat only a little  above that
 degree, it becomes blackened ; a part of the car-
 bon feparates  from  the  combination;  water
 flightly  acidulated paffes  over, accompanied by

  * The hydrogen g^, produced in  this way,  ]s not
pure, but holds a  confiderable portion of carbon  in fo-
lution.  It is carbo^ned hydrogen gas, called in  the
old chemical language, heavy  inflammable air.____T. 
 i8a          ELEMENTS

 a little oil; and the charcoal*, which remains in
 the retort, is  nearly a  third part ofthe original
 weight ofthe fugar.
   The operation of affinities which takes place,
 during  the decompofition, by  fire, of vegetables
 which contain  azot,   fuch  as  the cruciferous
 plants, and of thofe  containing phofphorus, is
 more complicated.   But, as thefe fubftances on-
 ly enter  into  the  compofition of vegetables in
 very  fmall quantities,  they   only,  apparently,
 produce  flight changes  upon the products of dif-
 tillation.  The  phofphorus  feems  to combine
 with carbon ; and,  acquiring fixity from that u-
 nion, remains  behind in  the  retort; while the
 azot, combining with  a part  of the  hydrogen,
 forms ammoniac]", or volatile alkali.
   Animal  fubftances,  being  compofed  nearly
 of the fame  elements  with cruciferous  plants,

  * The term charcoal is here retained, becanfe  it is
ftill contaminated with feveral foreign matters.  Carbon,
ftrklly ficaking, is only ufed  to denominate  the  pure
elementary and combuftible part of  charcoal, which pn.rt
acts alone  in combination?  and decompofitions.----T.
  ■f Dr Black's  p^opofed  tetm, c-ivmovc,  as   will be
more particularly noticed in the fequel,  fecms better a-
d.ipted, as a fingle term for this fubftance,  than the one
here ufed.  Befides, in the above,explanation, the ammo-
niac or animona, whichever  term be preferred, is net puie,
brint; combined with carbonic  acid  ; wherefore it ou^ht
to  hare been named carbonated ammoniac.----T. 
         OF  CHEMISTRY.       183

give  almoft  the fame products  in diftillation;
 with this  difference, that, as   they  contain a
greater quantity of hydrogen  and azot,  they
produce more oil and more ammoniac.   I  fhall
only  produce  one  fact as a proof of the exact-
nefs with which this theory explains all the  phe-
nomena that occur during  the diftillation  of a-
nimal fubftances;  which is  the rectification,
and total  decompofition, of volatile animal oil,
commonly known  by the name of Dinpels? oil.
When thefe oils are procured  by a firft  diftilla-
tion, in a naked fire, they are brown, from  con-
taining a little  carbon,  almoft in a  free ftate.
But they become quite  colourlefs by rectifica-
tion.   Even  in this ftate, the carbon in  their
compofition has fo flight  a  connection with the
other  elements, as to feparate  from them by
mere expofure  to  the air.  If we put a quanti-
ty of this animal oil, well rectified,  and confe-
quently clear, limpid,  and  tranfparent,  inro a
bell-glafs  filled with oxygen gas over mercury,
in a fhort time the gas is much  dirrdniihod, be-
ing abforbed by the oil. The oxygen, combining
with the hydrogen of the oil, forms water, which
finks  to the bottom.   At  the fame time the car-
bon, which  was combined  with the  hyrrc-'a-i
being fet free,  manifefts  itfelf by rendering the
oil  black.  Hence the only way of preferring
thefe oils colourleis and  trar. (parent, is by keep-
ing them in bottles perfectly fall, and accurate- 
i?4
ELEMENTS
ly corked, to hinder the eontatt of air, which
always difcolours them.
   Succeffive rectifications   of this oil furnifh
another .phenomenon  confirming  our theory.
In each diftillation a fmall  quantity of charcoal
remains in the retort; and a little water is form-
ed, by  the  union of the oxygen contained in
the air  of the diftilling veffels with the hydro-
gen ofthe oil.   As this takes place in  each fuc-
ceffive diftillation, if we make ufe of large vef-
fels and a confiderable degree of heat, we at laft
decompofe the whole of the oil, and change it
entirely  into water  and charcoal.   When  we
ufe fmall vefibis, and efpecially when we  em-
ploy a flow fire,-or a degree of heat only a little
above that of boiling .water, the total decompor
fition of  thefe oils, by repeated  diftillation, is
greatly  more tedious,  and more difficultly ac-
complifhed.   I fhall give a  particular detail to
the academy, in a feparate memoir, of all  my
experiments   upon  the decompofition of  oil,
But v/nat I have related above may fuifice to give
juft general  ideas of the .compofition of animal
and vegetable fubftances, and of their decompo ■
tlon bv the action office. 
OF  CHEMISTRY.
185
              CHAP.    XIII.


Of the  Decompofition of  Vegetable Oxyds  by  the
              Vinous Fermentation.


      THE  manner in which wine, cyder, mead,
       and all the liquors  formed by the fpiri-
tous fermentation, are  produced, is  well known
to every one.  The juice of grapes  or of apples
being expreffed, and the latter being diluted with
water, they  are put into  large  vats,  which  are
kept in a  temperature  of  at leaft 54.5^ ofthe
thermometer.   A rapid inteftine  motion,  or fer-
mentation,  very foon takes place j  numerous
globules form in the liquid, and burft at the fur-
face.  When the fermentation is at its height,
the quantity of gas difengaged  is fo  great, as to
make the  liquor appear  as if  boiling  violently
over afire.  When this gas is carefully  gather-
ed, it is  found  to  be carbonic acid  perfectly
pure*, and  free  from admixture with any other
fpecies of air or gas.

  * This aflertion of the perfecl  purity of carbonic acid gas,
difeno-aged during  the  vinous  fermentation, muft be taken
with fome allowance ;  for it almoft always,. I believe ccmilaiit-
                       Aa 
i36        .ELEMENTS
    When the fermentation is  completed,  the
 juice of grapes is changed, from being fweet and
 full of  fugar, into a  vinous  liquor,  which no
 longer contains any  fugar, and  from  which we
 procure,  by diftillation, an inflammable liquor,
 known  in commerce  under the name of Spirit
 of Wine.  As this liquor is produced by the fer-
 mentation of any faccharine  matter whatever,
 diluted  with water,  it  muft have  been'contrary
 to  the  principles of  our nomenclature  to call
 it fpirit of wine,  rather than fpirit of cyder,
 or of fermented fugar.  Wherefore, we have a-
 dopted  a more  general  term, and  the Arabic
 word alkoholTeems extremely proper for the pur-
 pofe.
   This operation is  one of the  moft  extraordi-
 nary in  chemiftry.   We muft  examine whence
 proceed  the difengaged carbonic  acid and the
 inflammable liquor produced, and in what man-
 ner a fweet vegetable oxyd becomes  thus  con-
 verted into two fuch oppofite fubftances, where-
 of one is combuftible,  and the  other  eminently
 the contrary.   To  folve thefe two queftions, it
 is neceffary to be previoufly acquainted with the
 analyfis ofthe fermentable fubftance, and  of the
 products of the fermentation.
Iy, contains fome alkohol, befides a confiderable quantity of
aqueous gas or water, in folution.  The  latter  does not af-
fstt its purity ; the former does fo in fome degree.—T. 
OF  CHEMISTRY.
187
     We  may lay  it down,  as  an inconteftible
   axiom,  that, in  all the operations  of art and
   nature,  nothing is created.   An equal quantity
   of matter exifts both before and after the expe-
   riment ■, the quality and  quantity of the ele-
   ments remain precifely  the  fame : and nothing
   takes place  beyond  changes and modifications
   in the  combinations of thefe elements.   Upon
  this principle, the whole art  of performing che-
  mical experiments depends.  We muft always
  fuppofe an exa6l equalky between the elements of
  the body examined, and thofe ofthe products of
  its analyfis.
    Hence, fince from muft of grapes we procure
  alkohol  and carbonic acid,  I have undoubted
  right  to  fuppofe that muft confifts of carbonic
  acid  and alkohol*.  From thefe  premifes, we
  have  two methods of  afcertaining what pafifes
  during vinous fermentation :   Either  by deter-
  mining the nature  of, and  the elements which
 compofe, the fermentable fubftances -,  or by ac-
 curately  examining the products refulting from
 fermentation.  And it is evident,  that the know-

   * Jn this affertion,  the confequences do notftriaiy follow
from the premifes j becaufe, from the muft of grapes we pro-
cure  carbonic acid and alkohol,  it  is a neceffary confequence
that the  original muft contains the conftituent  elements of
carbonic acid and of alkohol, but not that thefe produ&s of
fermentation are already formed—T. 
i88        ELEMENTS

Icdce of  either of thefe muft lead to accurate
conditions concerning the nature and compo-
fition of the  other.  From thefe confiderations,
it became neceffary accurately to determine the
conftituent elements of the fermentable fubftan-
 ces : and, for this purpofe,  I did not make ufe
 of the compound juices of fruits, the rigorous
 analyfis of which is perhaps impoffible but made
 choice of fugar,  which  is eafily analyfed,  and
 the nature  of which  I  have already explained.
 This fubftance  is a  true vegetable oxyd with
 two bafes,  compofed of hydrogen and carbon,
 brought to  the ftate of an oxyd, by means of a
  certain proportion of oxygen;  and thefe three
  elements are  combined  in fuch  a way,  that a
  very flight  force is fufficient  to deftroy the e-
   quilibrium of their connection.  By a long train
   of experiments,  made in various ways, and of-
   ten repeated, Iafcertained, that the proportions, in
   which thefe ingredients exift in fugar, are near-
   ly 8 parts of hydrogen,  64 parts of oxygen, and
   28 parts of  carbon, all by weight, forming 100
   parts  of fugar.
      Suaar  mud  be  mixed  with about four
    umes& its  weight of water,  to  render  it  fuf-
    ceptible  of fermentation: and  even  then the
    equilibrium  of its elements  would  remain un-
    dLrbed, without the affiftance of fome fub-
    ftance to  give a commencement to the ter- 
OF  CHEMISTRY.
189
mentation*.   This is accompliihed by means of
a little yeaft from beer :  and, when the fermen-
tation is once excited,  it continues of itfelf until
completed.  I fhall,  in  another  place,  give an
account of the  effects of yeaft,  and other fer-
ments,  upon  fermentable  fubftances.    I  have
ufually  employed 10 lbs. of yeaft, in  the ftate of
palte, for each 100 lbs. of fugar,  with  as much
water as is four times  the weight of the fugar.
I fhall give the refults of my experiments exactly
as they were  obtained, preferving even the frac-
tions produced by calculation.
  * This is not ftriftly true; for, efpecially in warm weathers,
all fyrups are apt to run into fermentation, unlefs very rich of
the fugar, and carefully preferved.  At the fame time,  this
fpontaneous fermentation is not fo regular as when affifted by
yeaft, and is apt  to become in part acetous,  before completing
the vinous procefs.—T. 
ijo        ELEMENTS
      TAptj I.   Materials of Fermentation*.


Water           ..          .             J£
Sugar
 *                                "*       i oo
Yeaft, in palte, 10 lit.   ("Water      -       T^^oiioi
  •ompofed of         {Dry veaft     .      j^ffi

                                   Total 9 to. /£j.



Table II.   Conftituent Elements of the Materials

                  of Fermentation.
407.2391493 fl,. of water,    ("Hydrogen     61.0858724
  compofed of              \ Oxygen      346.1532769

    ..   .                   C Hydrogen      8.
I0o lbs. fugar,  compofed of  1 Oxygen        64.
                           (. Carbon         28.


2.7608507 /Ai. of dry yeaft,   ) Oxygen^      1 Si J7
  compofed of             \ Carbon          7876519
                          (Azot            -0393815

                             Total weight 510. lbs.
  * The quantities in the original are expreffed  in the com-
mon divifions  of the Paris pound : but,  to render the refults
more generally ufeful to the Englifh reader, they are all here

reduced to decimals, which anfwer equally for any pound.__T. 
OF  CHEMISTRY.
191
Table III.   Recapitulation of thefe Elements.
c
w
too
"of the water
ofthe water
   >£<  in the yeaft J
   O / of the fugar
      ofthe dry yeaft

   c T of the water
   So \ of the water   ")
   *i /? th,e yeaft 3"
   ^ y or the fugar
   ^ (_of the dry yeaft

 J.  c  (" of the fugar
Uj (ofthe yeaft

Azot of the yeaft
 ills.
411.7970226
  lbs.
34°-
  6.1532769
 64.
  *-6437457
 60.        *\
  1.0858724 ( 69.3759440
  8.        f
 0.2900716 J

   7876519  }  28.78765I9

      ________°-°393815
      In all 510. lbs.
28
 o
   Having thus accurately determined  the na-
 ture  and  quantity of  the  conftituent  elements
 ofthe materials fubmitted  to fermentation,  we
 have next to  examine  the  products  refulting
 from that  procefs.  For  this purpofe,  I placed
 the above  S10 lbs. of  fermentable liquor  in  a
proper* apparatus,  by means of which  I could
accurately  determine  the quantity an4 quality
of gas difengaged during  the fermentation, and
* The above apparatus is defcribed in the Third Part.—A. 
192
ELEMENTS
could even weigh every one ofthe products fe-
parately at any period of the procefs I judged
proper.
  An hour or two after the fubftances are mixed
together, efpecially if they be kept in a tempe-
rature of from  66°  to 730 of the thermometer,
the firft marks of fermentation commence.   The
liquor turns thick and  frothy •, little  globules of
air are difengaged, which rife  and  burft at the
furface; the quantity of thefe globules  quickly
increafesj  and  there  is  a rapid  and abundant
production of very pure carbonic acid, accom-
panied with a fcum, which is the yeaft feparating
from the  mixture.   After fome  days,  lefs or
more according to the degree of heat,  the in-
teftine motion and difengagement ofgasdiminifh.
But thefe do not ceafe entirely ; nor  is the  fer-
mentation  completed  for a  confiderable time.
During the procefs, 35.3458116 U>S. of dry car-
bonic acid are difengaged,  which  carry  along
with them 13.9140625  lbs.  of water.  There
remain in the veffel 460.7401259 lbs. of vinous
liquor, flightly acidulous.  This is at firft muddy,
but  clears  of itfelf, and depofits  a portion of
yeaft.  When we feparately analyfe all thefe fub-
ftances,  which  is  effected by very troublefome
proceffes,   we  have the refults as given in the
following  Tables.  This procefs, with  all the
fubordinate calculations and analyfes, will be de-
tailed at large in the Memoirs ofthe Academy. 
OF   CHEMISTRY.
*93
Table IV.  Producls of Fermentation.
 35-3458i'6 lbs.  of carbo-f~
            nic acid, conJ °x^en    -    *5-+«K>oi7
            pofedof      | Carbon    -       9.8968099


 408.9780816 lbs. of water, f Oxygen    -    347-6314019
             compofed of \ Hydrogen       61.3466797

                         f Oxygen, combined
                         I   with hydrogen  3J-3897570
                           Hydrogen, combi-
            kohobcompo-^   "ef wlth oxygue.n  S-S39388o
            fed of       |  Hydr°gen' combi-
                            ned with carbon  4.0390625
                         ', Carbon, combined
                         L  with hydrogen  16.7333984

  2 5000000 lbs of dry  ace- C Hydrogen    -   o.i56t5oo
            tousacid, com-1 Oxygen    -      1.7187500
            pofed of      (Carbon      -    0.625 odoo

. 4.0940755 lbs. of refiduum f Hydrogen    -    0.3275825
            of fugar, com-1 Oxygen    -      2.6201172
            pofedof      £ Carbon    -      1.1463758

                         C Hydrogen    -    0.1450738
 1.3804254Ibs.of dry yeaft, ^Oxygen    -      0.8218317
           compofed of   j Carbon     -     0.3938802
                         ^Azot     -     0.0196397

$iotis.                                    510 lbs.

                       B b 
194
ELEMENTS
    T ab l e V.  Recapitulation of the ProduSls.


                                            lbs.
                        f Water     -    347.6314019
                        I Carbonic acid  -   25.4490017
409.6308595 lbs. of oxygen j Alkohol     -     31 389757°
           contained in the ; Acetous acid   -    1.7187500
                        ( Refiduum of fugar   2.6201172
                        L Yeaft      -      0.8218317

                        !Carbonic acid   -   9.8968099
                         Alkohol    -     167333984
                         Acetous acid   -   0.6250000
                         Refiduum of fugar   1.1463758
                         Yeaft      -      0.3938802
71.5540365 lbs. of hydro-^
            gen, contain- '
            ed in the
"Water    -   -  61.3466797
 Water ofthe alkohol 5 -5393 880
 Combined with  the
 carbon of the alkohol 4.0390625
 Acetous acid   -  0.1562500
 Refiduum of fugar  0.3275825
„ Yeaft      -     0.1450738
0.0196397/Ar. ofazot in the yeaft      -      0.0196397
$io lbs.                                  510/^.


   In the  calculation  of  thefe  refults,  I have
 been exact even  to  minutenefs:  Not  that it is
 poffible, in experiments of  this nature, to carry
 our  accuracy  fo  far; but  as  the  experiments
 were made only with a few pounds of fugar,  and
 as,  for  the  fake of  comparifon, I  reduced  the
 refults  of the  real  experiments  to the quintal, 
OF  CHEMISTRY.
 or imaginary hundred pounds, I thought it ne-
 ceffary to leave the fractional parts precifely as
 produced by calculation.
   When  we  confidcr the refults prefented by
 thefe  tables with attention,  it is eafy to difcover
 exactly what  occurs during fermentation.  In
 the firft place, out  of the ioo lbs. of fugar em-
 ployed, 4.0940755 lbs. remain, without having
 fuffered decompofition :  fo that,  in reality,  wc
 have only operated upon 95.905 9245/fo. of fugar j
 that is to fay,  upon 61.37979168 lbs.  of oxygen,
 7.67247396 lbs. of hydrogen, and 26.85365886
 lbs. of carbon.  By comparing thefe quantities,
 we find that they are fully fufficient for forming
 the whole of the alkohol, carbonic acid, and
 acetous acid,  produced by  the  fermentation.
 It is not,  therefore, neceffary to fuppofe  that
 any water  has been  decompofed during the ex-
 periment, unlefs it be  pretended that  the oxy-
 gen  and hydrogen exift in the fugar   already
 combined in that  form.  On the contrary, I
 have  already  made  it evident that  hydrogen,
 oxygen, and carbon, the  three conftituent ele-
 ments  of  vegetable fubftances,  remain  in  a
 ftate of equilibrium, or mutual union with each
 other,  which  fubfifts fo long as  this union re-
 mains undifturbed by increafed temperature,  or
 by means  of fome  new compound attraction j
and  that  then only thefe elements combine, 
 196          ELEMENTS

 two and two together, to form water and carbo-
 nic acid.
    The  effects  of the vinous fermentation upon
 fugar is thus reduced to the mere feparation of
 its elements into two portions; one part is oxy-
 genated at  the expence of  the other, fo as to
 form carbonic acid ; while the other part, being
 difoxygenated in favour of  the former, is con-
 verted into the combuftible fubftance called al-
 kohol ; therefore, if it were poffible to re-unite
  alkohol and  carbonic acid  together, we fhould
 form fugar.    It is evident that  the  carbon
 and  hydrogen in the alkohol do not exift in the
 ftate of oil, but that they are combined with a
 portion of oxygen, which renders  them mifci-
 ble  with  water; wherefore thefe three fubftan-
 ces, oxygen,  hydrogen, and carbon,  exift here
 likewife in a fpecies of equilibrium, or recipro-
 cal  combination;  and,  in face, when  they are
, made to pafs through a  red  hot tube of glafs or
 porcelain, this union or equilibrium is deftroyed;
 thefe elements become recombined two and two,
  and water and carbonic acid are formed.
    I had formerly advanced, in  my  firft  Me-
  moirs  upon  the formation of water, that it was
  decompofed in a great number of chemical ex-
  periments,  and particularly during the  vinous
  fermentation.  I then fuppofed that water exift-
 ed ready formed in fugar, though I am now con-
 vinced that  fugar only  contains  the  elements 
        O F  CHEMISTRY.      197

proper for compofing it.  It may be readily con-
ceived, that it muft have coft me a good deal to
abandon  my firft notions.   But by feveral years
reflection, and  after  a great number of experi-
ments and obfervations upon vegetable fubftances,
I have fixed my ideas as above.
  I fhall finifh what I have to fay upon vinous
fermentation, by obferving, 'that it furniflies us
with the means of analyfing  fugar  and every
vegetable fermentable matter.   We may confi-
derthe ftibftances fubmitted to fermentation, and
the products  refulting from that operation, as
forming an algebraic  equation  : and, by fuccef-
fively fuppofing each  of the  elements  in  this
equation unknown, we can  calculate their values
in fucceffion, and thus verify our experiments by
calculation, and our calculations by experiment,
reciprocally.  I have often fuccefsfully employed
this method for correcting the firft refults of my
experiments, and to direct me in the proper road
for repeating them to advantage.  I have explain-
ed myfelf more at  large upon  this fubject, in a
Memoir upon vinous  fermentation already pre-
fented to the academy, and which v/ill fpeedily
be publifhed. 
198
ELEMENTS
              CHAP.  XIV.

        Of the Putrefaclive Fermentation.

    THE phenomena  of putrefaction are caufed,
      like thofe of vinous fermentation,  by the
operation  of  extremely  complicated affinities.
The  conftituent  elements,  of the bodies which
are fubmitted to this  procefs, ceafe to continue
in equilibrium, in their original threefold com-
bination,  and form themfelves anew into binary
combinations*, or compounds confifting of two
elements only.  But  thefe are entirely different
from  the refults produced by the vinous fermen-
tation.  Inftead of part ofthe hydrogen remaining
united with part  of  the  water and carbon,  to
form  alkohol, as  in the vinous fermentation, the
whole of the hydrogen is  diffipated, during pu-
trefaction,  in the  form of hydrogen gas; while,
at the fame   time,  the  oxygen   and  carbon,
uniting  with  caloric,   efcape  in   the form  of
carbonic  acid;   fo   that,   when  the  whole
procefs  is  finifhed,   efpecially  if the materials
  * Binary combinations are fuch as confift of two fimple
elements  combined together.   Ternary,  and  quaternary,
confift of three and of four elements.—T. 
         O F  C H E M I S T R Y.      199

 have   been mixed  with a  fufficient  quanti-
 ty of water,  noting remains but  the  earth  of
 the vegetable,  mixed with a  fmall portion of
 charcoal  and iron.   Thus,  putrefaction is no-
 thing more than a complete  analyfis of vege-
 table fubftance; during which the whole of the
 conftituent elements is difengaged in form of gas,
 except the earth, which remains in the ftate  of
 mould*.
    Such is the  refult of putrefaction, when the
 fubftances fubmitted to it contain only  oxygen,
 hydrogen,  carbon,  and a little  earth.   But
 this cafe  is rare:  and thefe  fubftances  putrify
 imperfectly and with  difficulty, and require  a
 confiderable time  to  complete  their putrefac-
 tion.   It is otherwife with fubftances containing
 azot^ which indeed exifts in all animal matters,
 and even in a  confiderable number of vegetable
 fubftances. This additional element is remark-
 ably favourable to putrefaction:  and  for this
 reafon, animal matter  is  mixed with vegetable,
 when the   putrefaction  of thefe  is wifhed to be
 haftened.   The whole art  of  forming compofts
 and dunghills, for  the purpofes of agriculture,
 confifts in  the  proper application of this  admix-
 ture.

  * In the third part will be given the defcription of  an ap-
paratus proper for being ufed in experiments 6f this kind.—A. 
soo
ELEMENTS
  The addition of azot to the materials of putre-
faction, not only accelerates the  procefs, but
that element likewife combines with part of the
hydrogen, and forms a new  fubftance,  called
volatile  alkali,  or ammoniac.   The  refults ob-
tained by analyfing animal matters,  by different
proceffes, leave no room  for doubt with regard
to the conftituent  elements of ammoniac ; for,
whenever the azot has been previoufly feparated
from thefe fubftances, no ammoniac is produced;
and  in all cafes  they furnifh ammoniac  only in
proportion to the azot they contain.   This com-
pofition of ammoniac is likewife fully proved by
Mr Berthollet, in the memoirs ofthe Academy
for 1781, p. 316,  where he gives a variety of
analytical proceffes by which ammoniac is decom-
pofed, and its  two elements, azot and hydrogen,
procured Separately.
  I have already mentioned, in Chap.  X. that
almoft all combuftible  bodies  are  capable of
being combined with each other.  Hydrogen gas
poffeffes this quality, of  combining  with other
combuftible fubftances,  in  an eminent degree.
It diffolves carbon,  fulphur,  and  phofpohorus,
producing  the   compounds   named  carbonated
hydrogen  gas,  fulphurated hydrogen  gas,   and
phofphorated hydrogen gas.   The  two latter  of
thefe gaffes have  a peculiarly difagreeable flavour.
The fulphurated  hydrogen gas has  a ftrong re-
femblance to  the  fmcll  of rotten  eggs: and 
        OF  CHEMISTRY.      201

the phofphorated fmells exactly like putrid fifh.
Ammoniac has likewife a peculiar  odour,  not
lefs penetrating  or lefs difagreeable than thefe
other gaffes.   From the mixture of thefe differ-
ent flavours, proceeds the fcetor which always ac-
companies  the  putrefaction of animal  fubftan-
ces.  Sometimes  the  ammoniac  predominates,
which is eafily perceived by its fharpnefs upon
 the eyes ;  fometimes,  as in feculent matters, the
 fulphurated gas is moftprevalent: and fometimes,
 as in putrid  herrings, the  phofphorated hydro-
 gen gas is moft abundant.
   I long fuppofed, that nothing  could  derange
 or interrupt the  courfe of putrefaction.   But
 Mr Fourcroy and Mr Thouret  have  obferved
 fome peculiar phenomena in dead  bodies, bu-
 ried at a certain depth, and preferved to  a cer-
 tain degree, from contact  with  air; having
 found the mufcular flefh  frequently converted
 into true animal fat *.  This muft  have arifen
 from  the difengagement,  by fome   unknown
 caufe, of the azot, naturally contained in the
 animal fubftance, leaving  only the  hydrogen
 and carbon remaining, which are  the  elements
 proper for producing fat or oil.   This obferva-

    * This procefs has been lately imitated artificially : and
 a fatty  fubftance,  exaftly fimilar in all refpefts to Sperma-
 ceti, can be readily made from the fkfh or mufcular parts of
 all animal bodies.—T.
                      Cc 
262
ELEMENTS
 tion, on the poflibility of converting animal fub-
 ftances into fat, may fome time or other lead to
 difcoveries of great importance tofociety.   The
 fseces of animals,   and  other  excrementious
 matters,  are chiefly compofed of carbon  and
 hydrogen ;  and approach confiderably to the na-
 ture of oil, of which they furnifh a confiderable
 quantity by diftillation with a naked fire. But the
 intolerable fcetor, which accompanies all the pro-
 ducts of thefe fubftances, prevents our expecting
 that,  at leaft for a long time, they can be render-
 ed ufeful in  any other way than as manures.
  I have only given conjectural approximations,
 in this Chapter, upon the compofition of animal
 fubftances, which is hitherto imperfectly under-
 ftood. We know, that they are compofed of hy-
 drogen, carbon, azot, phofphorus, and fulphur,
 all of which, in a ftate of quintuple combination,
 are brought  to the ftate  of oxyd  by a larger or
fmaller quantity of oxygen.  We are, however,
ftill unacquainted with the proportions in which
thefe fubftances are combined ;  and muft leave it
to time to complete this part of chemical analyfis,
as it has already done with  feveral others. 
OF  CHEMISTRY.      203
CHAP.  XV.
         Ofthe Acetous Fermentation.


     THE acetous fermentation is nothing more
      than the  acidification or oxygenation of
wine *, produced in the open air,  by means of
the abforption  of oxygen.   The refulting acid
is the acetous acid, commonly called  Vinegar,
which is  compofed of hydrogen  and  carbon
united together, in proportions not yet afcertain*
ed, and changed into the acid ftate by oxygen.
As vinegar is an acid, we might conclude from
analogy, that it contains oxygen : but   this is
put  beyond doubt  by direct experiments.   In
the firft place,  we cannot change wine into vine^'
gar without the contact of air  containing oxy-
gen.   Secondly, this procefs is accompanied by
a diminution of the volume  of the air in which
it is carried on, from the abforption of its oxy-
gen : and thirdly, wine may be changed into
vinegar by any other means of oxygenation.

  * The word Wine, in this chapter, is ufed to fignify the
liquor produced by the vinous fermentation, whatever vege-
table fubftance may have been ufed for obtaining it.—T. 
4Q4
ELEMENTS
  Independent  of the  proofs which thefe  facts
furnifh, ofthe acetous  acid being produced  by
the oxygenation of wine, an  experiment made
by Mr Chaptel, Profeffor of Chemiftry at Moni-
pelier, gives a diftinct view of what takes place
in this procefs.   He impregnated fome water
with about its own bulk of carbonic acid from
fermenting beer ;  and placed  this water in a
cellar, vin veffels communicating with the air :
and in a fhort time, the whole was converted in-
to acetous  acid.   This carbonic acid gas, pro-
cured from  beer vats  in  fermentation, is not
perfedly pure,  but contains a  great quantity  of
alkohol in folution ; wherefore water impregna-
ted with it, contains all the  materials neceffary
for forming the acetous acid.   The  alkohol fur-
nifhes hydrogen and one portion of carbon. The
carbonic acid  furnifhes oxygen  and the reft of
the carbon.   And the air of the atmofphere fur-
nifhes the reft ofthe oxygen neceffary for chang-
ing the mixture into acetous acid.  From this
obfervation it follows,  that nothing  but hydro*
gen is wanting, to convert carbonic acid into ace-
tous acid ;  or,  more generally,  that, by means
of hydrogen,  and according  to the degree  of
oxygenation, carbonic acid may be changed into
all the vegetable acids; and,  on the contrary,
that, by depriving any of the  vegetable  acids of
their hydrogen, they maybe converted into car-
bonic acid. 
        OF  CHEMISTRY.      205

  Although  the  principal facts relating to the
acetous acid are well known, yet numerical pre-
cifion is  ftill wanting, until furnifhed by more
exact experiments than any  hitherto perform-
ed ;  wherefore I  fhall  not enlarge any  farther
upon the fubject.  It  is fufficiently fhewn  by
what has been faid,  that the conftitution of all
the vegetable acids and oxyds  is exactly con-
formable to the formation  of vinegar.   But far-
ther experiments  are neceffary  to teach us the
proportion of the conftituent  elements in  all
thefe acids and  oxyds.   We  may  eafily per-
ceive, however, that this part of chemiftry, like
all the reft of its divifions,  makes rapid progrefs
towards perfection; and that it is already ren-
dered greatly more fimple  than was formerly be-
lieved. 
a©6         ELEMENTS
              CHAP.  XVI.

Ofthe Formation of Neutral  Salts, and of their
                different Bafes.


        E have juft feen,  that all  the oxyds and
          acids  from the animal and  vegetable
kingdoms, are formed from a fmall  number of
fimple elements, by means of combination with
oxygen, or at leaft from fuch bodies as have not
hitherto been fufceptible of decompofition,  and
which muft therefore be confidered as fimple fub-
ftances, in the prefent ftate of our knowledge:
thefe are azot, fulphur, phofphorus, carbon, hy?
drogen,  and the muriatic radical *.   We may
juftly admire  the fimplicity of the  means  em-
ployed by  nature  to  multiply  qualities  and
forms,   whether  by combining three or  four
acidifiable bafes in different proportions, or by


  * I have not ventured to omit this element,  as here enu-
merated with the other principles of animal  and  vegetable
fubftances, though it is not at all taken notice of In the pre-
ceding chapters,  as entering, into the  compofition of thefe
bodies.  It has been  already mentioned, in a former note,
that the muriatic radical is  now difcovered, or at leaft fuf-
pc£ted,  to be hydrogen.—T.
w 
OF  CHEMISTRY.     207
 altering the dofe of oxygeti employed for oxy-
 dating or acidifying them.  We fhall find the
 means no lefs fimple and diverfified,  and as a-
 bundantly  productive  of  forms and qualities,
 in the order of bodies we are  now about to
 treat of.
   Acidifiable fubftances,  by combining with-
 oxygen,  and their confequent converfion into
 acids, acquire a great fufceptibility for  farther
 combination.  They become capable of  uniting
 with alkaline, earthy,  and metallic bodies, by
 which means neutral falts  are formed.   Acids
 may therefore be confidered as truefalifying prin-
 ciples : and the fubftances with which they unite
 to form neutral falts may be czlledfalifiable bafes.
 The nature ofthe union which thefe two  princi-
 ples form with each other, is meant as the fubject
 ofthe prefent chapter.
   The  foregoing  view  of the  acids prevents
 them from being confidered  as  falts, though
 they are poffeffed of many of the principal  pro-
 perties of faline bodies,  as  folubility in  water,
 &c.   It  is already  obferved,  that they are the
 refults of a firft order  of combination,  being
 compofed of two fimple elements, or at leaft of
elements which act as  if they were fimple : and
they may therefore be ranked, to ufe the lan-
guage of  Stahl,  in  the  order of mixts.   The
neutral falts, on the  contrary, are  of a  feconda-
ry order of combination, being formed by the 
208         ELEMENTS

union of two  mixts with each  other ;  and may
therefore be  termed  compounds.   Hence  I fhall
not arrangethe alkalies*, or earths, in the clafs of
falts, to which I allot  only fuch as are compofed
of an oxygenated fubftance, united to a falifiable
bafe.
   I  have already enlarged fufficiently  upon  the
formation of acids in the preceding chapter ; and
fhall not add any thing farther upon that  fubject.
But, having as yet taken  no notice  of the falifi-
able bafes which are capableof uniting with them
to form  neutral falts, I mean,  in this chapter, to
give an account of the nature and origin of each
of thefe bafes.   Thefe are  potafh, foda,  ammo-
niac, lime, magnefia, barytes,  argillj,  and  all
the  metallic bodies.

                §  i.   Of Potafh.

   We have already fhewn,  that, when  a vege-
 table fubftance is  fubmitted to the action of fire

   *  Perhaps thus rejecting the alkalies from the clafs of falts,
may be confidered  as a capital defect, in the  method  here
adopted ; and I am ready to admit the charge.   But this in-
convenience is compenfated by fo many advantages, that I
could not think it of fufficient confequence to make me alter
 my plan.—A.
   f Called Alumine by  Mr Lavoifier.  But  as Argill has
 been in a manner naturalized to the  language  for this fub-
 ftance by Mr Kirwan,  I have ventured to  ufe it in prefer-
 ence.—T. 
OF CHEMISTRY.
209
in diftilling veffels, its component elements, oxy-
gen, hydrogen, and  carbon, which  formed a
threefold combination in a ftate of equilibrium,
unite* two and  two,  in  obedience to  affinities
which ad conformably  to the degree  of heat
employed.   Thus, at the firft application of the
fire, whenever  the  heat produced exceeds the
temperature of boiling  water, part of the oxy-
gen and hydrogen unite to form water.  Soon
after, the reft of the hydrogen, and part of the
carbon, combine into oil:  and, laftly, when the
fire  is pufhed to  the red heat, the oil  and wa-
ter, which had  been formed  in  the early part
of the procefs,  become again decompofed ; the
oxygen and part of the carbon  unite  to  form
carbonic acid ;  a large quantity of hydrogen gas
is fet free j  and nothing  but charcoal remains in
the retort.
   A great  part of thefe phenomena  occur du-
ring the combuftion of vegetables in  the open
air.   But,  in this cafe,  the prefence of the air
introduces  three  new fubftances, the  oxygen
and azot of the air, and caloric :  and,  of thefe,
two at leaft produce  confiderable changes in the
refults of the operation.  In proportion as the
hydrogen of  the vegetable,  or  that  which
arifes from the decompofition of the water,  is
forced out in the  form of hydrogen gas, by the
progrefs ofthe fire,  it is fet on fire immediately
upon coming into contact with the air ;  water is
again formed ; and the greater part of the calo-
                     Dd 
21$
ELEMENTS
ric  of the two gaffes becoming free,  produces
flame.  When all the hydrogen gas is driven
out, burnt, and again  reduced to water, the re-
maining carbon continues to burn, but without
flame.  It is formed into carbonic acid, which
carries off a portion of caloric fufficient to give
it the gaffeous form.  The reft  of the caloric,
from  the oxygen of the air, being fet free,  pro-
duces  the heat and light obferved  during the
combuftion of the carbon. The whole vegetable
is thus reduced to water and carbonic acid : and
nothing remains but a fmall portion of grey ear-
thy matter, called afhes, being the only really fix-
ed principles which enter into  the conftitution
of vegetables.
  The earth, or rather afhes,  which feldom ex-
ceeds a twentieth part of the weight of the ve-
getable, contains a fubftance of a particular na-
ture,  known under the name of fixed  vegeta-
ble  alkali, or potafh.  To obtain this,  water is
poured upon the afhes, which diffolves the  pot-
afh, and leaves  the afhes which are infoluble.
By  afterwards evaporating the water, we obtain
the potafh in a white concrete form.   It is very
fixed, even in a very high degree of heat.  I do
not mean here to defcribe the art of preparing
potafli, or the method of procuring it in a ftate
of purity ; but have entered into the above detail,
merely that I might not ufe any  word,  not pre-
vioufly explained. 
OF  CHEMISTRY.
211
  The potafh, obtained by this procefs, is always
lefs or more faturated with carbonic acid, which
is eafily accounted for.   As the potafh does not
form,  or at leaft is not fet free, but in propor-
tion as the carbon of the vegetable is converted
into carbonic acid,  by the  addition  of oxygen,
either from the air or the water, it- follows, that
each particle of potafli, at  the inftant of its for-
mation, or at leaft of its liberation, is in contadt
with a particle of carbonic acid: and as  there is
a confiderable affinity  between  thefe  two fub-
ftances,  they naturally combine together.   Al-
though the carbonic acid has  lefs affinity  with
potafh than any other acid, yet  it is difficult to
feparate the laft  portions  from it.   The  moft
ufual method of accomplifhing this, is, to  diffolve
the potafh  in water.   To  this folution  two  or
three  times its  weight of quicklime  are  added.
Then the liquor is filtrated,  and  evaporated in
clofe veffels.   The faline fubftance,  left  by  the
evaporation, is potafh, almoft entirely deprived of
carbonic acid.  In this ftate,  it  is foluble in an
equal Weight of  water,  and even attracts  the
moifture of the air with  great avidity.   By this
property it furnifhes us with an  excellent means
of rendering air or gas dry, by expofing them to
its  action.   In this ftate,  it is foluble  in alko-
hol, though not when combined with carbonic
acid :   and  Mr Berthollet employs this property
as a method of procuring potafh in the ftate of
perfect purity. 
211
ELEMENTS
  All vegetables yield lefs or more of potafh in
confequence of combuftion; but it is furnifhed
in various degrees of purity by  different vege-
tables : ufually,  indeed,  from whatever fource
it be procured, it is mixed with different falts,
from which, however, it is eafily feparable.  We
can hardly entertain a doubt, that  the afhes, or
earth, which is left by vegetables in combuftion,
pre-exifted in them before they  were burnt,
forming  what may  be  called the  fkeleton, or
offeous  part  of  the vegetable.  But it is quite
otherwife with potafh.  This fubftance has never
yet been  procured from vegetables but by means
of proceffes, or intermedia,  capable of furnilhing
oxygen and  azot, fuch  as combuftion,  or by
means of nitric acid ; fo that it is not yet demon^
ftrated that potafh  may  not be a produce from
thefe operations. I have begun a feries of experi-
ments upon this fubject, and hope foon to be able
to give an account of their refults.

               § 2.  Of Soda.

  Soda,  like potafh, is  an alkali  procured by
lixiviation from the afhes of burnt plants, but
only from  thofe which grow upon the fea-fide,
and efpecially from the herb kali, whence is de-
rived the name alkali,  given to this fubftance
by  the   Arabians.   It has  fome  properties  in
common with potafh, and others which are en-
tirely different.  In general,  thefe two fubftan- 
          OF  CHEMISTRY.       213

 ces have peculiar characters in their faline com-
 binations, which  are proper to each, and  confe-
 quently diftinguifh them from each other. Thus
 foda, which, as obtained from  marine plants, is
 ufually  entirely  faturated with  carbonic acid,
 does not attract the humidity of the  atmofphere
 like potafh :  but,  on the contrary, it  deficcates ;
 its cryftals efflorefce,  and are converted into a
 white powder, having all the properties of foda,
 which it really is,  having only loft its water of
 cryftallization.
   Hitherto we  are  not better  acquainted with
 the conftituent  elements of foda than with thofe
 of potafli,  being equally uncertain  whether it
 previoufly exifted ready formed in the vegetable,
 or if it be a combination of elements effected by
 combuftion.  Analogy leads us to fufpect, that
 azot is a conftituent element of all the alkalies,
 as is the cafe with ammoniac.  But we have only
 flight prefumptions, unconfirmed by any decifive
 experiments, refpecting the compofition of potafh
 and foda *.

  * There are fome experiments related in the Tranfa&iona
of the Turin Academy,  which give reafon for  fnppofing that
foda is a modification of magnefia.  This latter fubftance,
according to the experiments detailed by Baron Born,  and
mentioned in the additional fettion of this chapter, feems to
be a metallic oxyd.   From analogy, we may prefume,  that
potafli is likewife a metallic fubftance, in fome hitherto un-
known ftate of combination.  We (hall this exclude all  the
alkalies from the clafs  of fimple elementary fubftances.—T. 
214
ELEMENTS
             § 3.   Of Ammoniac.

  We have, however, very accurate knowledge
of the compofition of ammoniac  or volatile al-
kali, as  it was called by the old chemifts.  Mr
Berthollet, in the memoirs of the academy  for
1784, p. 316, has proved by analyfis, that 1000
parts of this fubftance confift of about 807 parts
of azot combined with 193 parts of hydrogen.
  Ammoniac is chiefly procurable from animal
fubftances by diftillation ; during which procefs
the azot and hydrogen neceffary to its  formati-
on unite in proper proportions.  It is not, how-
ever, procured pure by this procefs, being mix-
ed with oil and water, and moftly faturated with
carbonic acid.   To feparate thefe fubftances, it
is firft combined with an acid, the muriatic, for
inftance, and then difengaged from that com-
bination by  the addition  of lime  or  potafh.
When ammoniac is thus produced in its greateft
degree of purity,  it  can only  exift under the
gaffeous form, at leaft in the ufual temperature of
the atmofphere. It has an exceffively p'enetrating
fmell.  It is abforbed in large quantities by water,
efpecially if cold,  and affifted by compreflion.
Water, thus faturated with ammoniac, hasufually
been termed volatile alkaline fluor. We fliallcallit
either fimply ammoniac, or liquid ammoniac, and
ammoniacal gas, when it exifts in the aeriform
ftate *.
  * The nomenclature ofthe alkalies propofed by Dr Black,
 feems better than  that adopted by Mr Lavoifier and the 
           OF  CHEMISTRY.      215


  § 4.  Of Lime,  Magncfia, Barytes, and Argill.

    The compofition of thefe four earths is totally
 unknown ;  and,  until by new difcoveries their
 conftituent  elements are afcertained, we are cer-
 tainly  authorifed to confider them as fimple bo-
 dies.   Art has no fhare in the production of thefe
 earths  ; as they are all procured ready formed
 from nature.   But, as they have all, efpecially
 the three firft, great tendency to combination,
 they are never found pure.   Lime is ufually  fa-
 turated with carbonic acid in the ftate of chalk,
 calcareous fpars, moft ofthe marbles, &c.; fome-
 times  with  fulphuric  acid,  as in gypfum and
 plafter ftones ; at other times with  fluoric acid
 forming vitreous or fluor fpars;  and,  laftly,  it
 is found  in  the waters of the  fea, and of faline
 fprings, combined with muriatic acid. Of all the
 falifiable bafes, it is the moft  univerfally  fpread
 through nature.
   Magnefia is found in mineral waters, for the
 moft part  combined with  fulphuric acid.   It is
 likewife abundant in fea-water, united with muri-

 French chemifts.  Lixa, trona, and ammona, arc equally con-
 venient for ufe as potafla or potafh, foda, and ammoniac, and
 they are not  fo apt to lead into miftakes ; for the words of
 the new  French chemical nomenclature have too much re-
 femblance to old terms ufed for very different fubftances, or
at leaft for very different ftates, in a chemical  light, of the
fame fubftances.—T. 
S1g       ^ELEMENTS

atic acid :  and it exifts in a great number of ftonefl
of different kinds.
   Barytes is much lefs common than the two
preceding earths. It is found in the mineral king-
dom, combined with  fulphuric  acid, forming
heavy fpars, and fometimes, though rarely, uni-
ted to carbonic acid.
   Argill, or the bafe of  alum, having lefs ten-
dency to combination with  the other earths, is
often found in the ftate of argill,  uncombined
with any acid. It is chiefly procurable from clays,
of which, properly fpeaking,  it is the bafe,  or
chief ingredient *.
   " On the  4th of November 1793,  Dr Hope^
now affociated in the Edinburgh  chemical chair,
with Dr  Black,  read  to the  Royal  Society of
Edinburgh,  a very elaborate analyfis of a non-
defcript mineral, from the mines of Strontian in
Argylefhire ; to which, from  its place and ftruc-
ture, he gives the name of Strontitic fpar ; and
which he finds to confift of a peculiar earth, hi-
 therto  undifcovered in any other mineral body,
 combined with carbonic acid.   To this earth he
 has affigned the name  of Strontites, which agrees
 very well with the new nomenclature  ; only that,
 perhaps,  Strontita would havebeenmore regular,
 for the reafons mentioned in  the two preceding
 notes.   In this elementary treatife, a  detailed ac-

   * For reafons fimilar to thofe given in the preceding note,
 Dr Black p'opofes to name thefe four fimple earths, Calca,
 Magnefia,  Baryta, and Arga.—T. 
          OF  CHEMISTRY.      m7

 countofthis important difcovery cannotbegiven;
 for which the reader is referred to the Tranfanc-
 tions ofthe Royal Society of Edinburgh.  Stron-
 tites has a pungent acrid tafte ; is foluble both in
 hot and cold water,  but much more fo in hot,
 from which it cryftalizes in cooling ; its cold folu-
 tions attraft carbonic acid from the atmofphere,
 form a cruft of carbonate of Strontites on the fur-
 face, which breaks and falls to the bottom, ex-
 actly as in lime,  and is  rediffolved by an excefs
 of acid.  Strontites combines with the various
 acids, forming neutral falts ; and poffeffes differ-
 ent affinities with the acids from the other known
 earths.   One of its moft remarkable properties,
 both whenpureandin combination with the acids'
 is that of tinging the flame of combuftible bodies
 of a deep blood  red colour ;  to produce  which
 effect, however, fome moifture muft be prefent.
 The order of affinities ofthe principal acids with
 Strontites, as determined by Dr Hope's experi-
 ments, is as follows :
   Sulphuric.     Nitric.         Acetous.
   Oxalic.       Muriatic.      Arfeniac.
   Tartarous.     Succinic.      Boracic.
   Fluoric.       Phofphoric.    Carbonic.
   Its order of affinities with the feveral acids, re-
 lative to the other falifiable bafes, fo far as afcer-
 tained by Dr Hope, are inferted in the refpedive
 tables  in Part II.*"
  * The whole of this account of Strontites,  has been ad-
ded to the third Edition.—T.
                     Ee 
2l8
ELEMENTS
           § 5.   Of Metallic Bodies.

   The  metals,  except gold, and fometimes fil-
ver, are rarely found in the mineral kingdom in
their metallic ftate,  being ufually lefs or more
faturated with oxygen,  or combined with  ful-
phur, arfenic, fulphuric acid, muriatic acid, car-
bonic acid, or phofphoric acid.  Metallurgy, or
the doeimaftic art, teaches the means of fepara-
ting them  from thefe foreign matters j  and for
this purpofe we refer to fuch chemical books as
treat upon thefe operations.
   We are probably only acquainted as yet with
a part of the metallic fubftances exifting in na-
ture ; as all thofe which have a ftronger affinity
to oxygen  than carbon poffeffes,  are incapable,
hitherto, of being reduced to  the metallic ftate :
and, confequently, being only prefented to  our
obfervation undeT the form of oxyds,  are  con-
founded with earths.   It  is extremely probable,
that  barytes, which we have  juft now arranged
with earths, is in this fituation ; for in many ex-
periments it exhibits properties nearly approach-
ing to thofe of metallic bodies. It is even poffible,
that  all the fubftances we call earths, may be only
metallic oxyds, irreducible by any hitherto known
procefs.                                \
   Thofe metallic bodies  we are at prefent ac-
quainted with, and which we can reduce to the
• 
OF  CHEMISTRY.
219
metallic or reguline ftate, are the following fe-
venteen.
Latin Names.	Englifh Nam
i. Arfenicum	Arfenic.
2. Molybdenum	Molybdena,
3. Tungftenum	Tungftein.
4. Manganefum	Manganefe.
5. Nickolum	Nickel.
6. Cobaltum	Cobalt.
7. Bifmuthum	JSifmuth.
8. Antimonium -	Antimony.
9. Zincum	Zinc.
10. Ferrum	Iron.
11. Stannum	Tin.
12. Plumbum	Lead.
13. Cuprum	Copper.
14. Mercurium	Mercury.
15. Argentum	Silver.
16. Aurum	Gold.
17. Platinum	Platina.
  I only mean to confider thefe as falifiable bafes,
without entering at all upon the confideration of
their properties in the arts, and for the ufes of
fociety. In thefe points of view, each metal would
require a complete treatife,  which would lead
me far beyond the bounds I have prefcribed for
this work. 
229
ELEMENTS
  § 6.  Of the Metallic Nature ofthe Earths '*.

  In the laboratory of the Academy of the mines
at Chemnitz, in Lower Hungary,  fome experi-
ments have been lately  made, by Meffrs Tondi
and Ruprecht, by which the number ofthe me-
tals feems to be confiderably augmented. Befides
afcertaining the real metallic natureof Tungftein,
Molybdena, and Mangan'efe, which fome  che-
mifts had doubted,  but all of which have been
reduced to the reguline form by thefe two che-
mifts, they have fucceeded in procuring metallic
reguli from Chalk, Magnefia, and Barytes.   Of
thefe experiments it may be proper to give fome
account in this place, from the defcription of the
cabinet of Mademoifelle Raab, of Vienna, by
Baron Born.

                  Barytes.

  After having  purified fome Barytes, by re-
peated fufions and precipitations, it was mixed
with an eighth part of  its weight of powdered
charcoal,  and made into a pafte  with lintfeed
oil.  This was put into  a crucible,  furrounded
by powdered charcoal,  and fubmitted to a ftrong
melting heat, for an hour and a half.   A perfect
metallic regulus was procured, of an iron-grey

  * The whole of this fcc"lion was added by the Tranflator
to the fecond edition. 
PF  CHEMISTRY.
221
 colour and uniform metallic luftre.  Its texture is
 lamellated, compofed of large diftinct lamellae,
 which crofs each other.  It is  brittle, but  not
 hard, and readily takes a polifh ; is attracted by
 the magnet, notwithftanding every  poffible pre-
 caution to feparate any martial oxyd which might-
 have  previoufly  been  mixed with the mineral.
 The  fpecific gravity of this new metal is 6.744,
 water being taken as unity.

                  Magnefia.

   By treating the carbonat of  magnefia in  the
 fame  manner,  they obtained  a convex lump or
 globule of metallic regulus, of a bright grey  co-
 lour,  fimilar to platina which has not been fully
 purified from iron.  This regulus is harder th:;:i
 thofe  obtained from tungftein or molybdena.   It
 is granular, and fomewhat ftriated in its texture,
 when broken ; and is not affected by the magnet.
 Its fpecific gravity,  and other properties,  have
 not yet been afcertained.

                   Chalk.

  By the  fame method of proceeding,  a regulus
has likewife been procured from carbonat of chalk.
 The button was convex, and very compact in its
texture.   In colour and luftre it came very near
to the appearance of platina j  and it took a fine
polifh.  Its fpecific gravity,  and chemical rela- 
222
ELEMENTS
tions, have not yet been ascertained by experi*
ment.
  Thefe experiments have been  frequently re-
peated by the above-mentioned gentlemen, and
always  with  the fame  refults.   Should  they
eventually be confirmed by  rigorous examina-
tion,  a  new light will be thrown on feveral of
the moft difficult parts of chemiftry by thefe dif-
coveries, which have  already been in  a great
meafure predicted, by the conjecture of Mr La-
voifier,  who fuppofes that thofe fubftances, which
have long been confidered as primitive earths,
are only metallic oxyds, combined with oxygen;
and that their reduction has  hitherto been pre-
vented by the attraction which fubfifts  between
them and oxygen being ftronger  than  that be-
tween oxygen and carbon.
   Mr Baron Born adds  to the above   account,
" that he expects foon to learn, that the filicious
" and argillaceous earths  are likewife metallic
" oxyds; and that, in this cafe, the whole clafs
" of earths and ftones  will  difappear  from the
*f mineral kingdom.  The difcovery is  certainly
" one of the moft important that modern che-
" miftry has produced for a long while.   It muft
" have  great  influence in changing our metal-
" lurgic proceffes, which will thereby become
" more certain in  their refults,  and more fcien-
" title in their application.  Even every branch
" of chemiftry may receive confiderable  light 
O F  CHEMIST RT.
223
 " and improvement from their influence.  Per-
 " haps gold and filver are the only pure metal-
 " lie fubftances hitherto known ; as it is proba-
 " ble, that fome part ofthe, till now unknown,
 " metals, from the earths  employed for  facilita-
 " ting the fmelting of ores, may mix  with the
 " metals which we extract from thefe ores, and
 " debafe  them;  fo that,  inftead of fimple or
 " pure metals, which they  were formerly con-
 " fidered, thefe may only be alloys, of the  in-
 " gredients of which we are ftill ignorant. Per-
 " haps the reguli  of barytes and  of chalk are
 " foluble  in the fame acids,  and precipitated by
 " the fame elective attractions,  as the  regulus
 " of copper,  which may be the caufe of this
 " mixture not being hitherto fufpected.  From
 " this mixture,  or alloyage, the harfhnefs and
" greater  or leffer ductility of iron, copper, tin,
 " and other metals, may be derived.   All thefe
 " conjectures can only be afcertained or reject-
 " ed, when all  thefe  newly-difcovered  metals
" fhall have been properly examined, and their
" chemical affinities  compared accurately with
" thofe of the metals already known, and with
" each other.   One  thing feems highly proba-
" ble, that one or other  of thefe new metals
" will precipitate fome of the other metals  from
" folutions in a metallic form : and by  this pro-
" perty many metallurgic proceffes may become
" greatly facilitated and abridged." 
224
ELEMENTS
   Thefe difcoveries  give reafon to  hope,  that
 chemiftry may one day arrive at a moft beauti-
 ful ftate of fimplicity.  It is, perhaps, no im-
 probable conjecture, that all the bodies in na-
 ture may be referred to one clafs  of fimple com-
 buftible  elementary fubftances, to oxygen,  and
 to caloric ; and that,  from the various combi-
 nations of thefe with each other, all the variety
 produced by nature and art may arife.  The on-
 ly known difference between metals and  pure
 combuftibles, as they are called, is in degrees of
 qualities. They are all combuftible, that is,  they
 all combine with oxygen,  though under differ-
 ent degrees of temperature.   They are all folid,
 or liquid, or aeriform, fixed, or volatile, at differ-
 ent temperatures.   In different degrees of fatu-
 ration with  oxygen,  they form  oxyds, which
 have  alkaline properties,  or acids.   In the  ftate
 of oxyds, the formerly known metals have all
 the properties  of  what were  formerly  called
 primitive earths, which are now at leaft fufpea-
 ed of being metallic oxyds.   Even the aeriform
 nature of hydrogen and azot, which does  not
 feparate  them  from the reft fo far as combufti-
 bility  is concerned, is only a difference in degree
 of volatility.  We do not exclude mercury from
 the metals, becaufe it  is volatile in the tempe-
 rature of 6oo°, and fufes at —4o°, though  iron
is fixed at 240000, according  to Mr Wedge-
wood's experiments, and requires  250770 for its
fufion. Why  then fhould hydrogen and azot be 
OF  CHEMISTRY.
225
 excluded from a  clafs with which they agree
 in fo many particulars, becaufe their points of
 fufion and volatility are perhaps as many degrees
 below thofe belonging to mercury, as this latter
 falls fhort of  thofe of iron : or why fhould car-
 bon, fulphur,  and phofphorus, not be confidered
 as metals, becaufe their fpecific gravity, and luftre,
 and ductility, differ from the bodies called metals,
 which diaer fo much in thefe particulars among
 themfelves ?
   To thefe three new metals,  Mr Tondi wifhes
 to give the names of borbonium, for the regulus
 of barytes ;  auftrum, for the regulus from mag-
 nefia; and  pariheuum  for that  of chalk.   Ic
 were  hard to deny a difcoverer the right of giv-
 ing names to his own difcoveries, without fome
'rcafonable objection.  But thefe  names would
 introduce confufion into  chemical nomencla-
 ture, which it  has been the great object of  the
 French chemifts to  reform, and render regular ;
 wherefore I would  propofe that they fliould be
 named barytum, magnefium, and calcum.   Thefe
 accord with the reformed old names ofthe fub-
 ftances from  which they  are  procured, merely
 by changing to the  neuter gender, in which all
 the names of the metals are placed in the new
 nomenclature : and then the three, formerly cal- •
 led, earths will be oxyds of thefe metals refpec-
 tively, or baryta, magnefia, and calca, if fingle
 terms are preferred, thefe latter being in the femi-
                     F f 
226          ELEMENTS

nine gender,  which is appropriated to alkaline
fubftances in the new nomenclature.
  It muft  not,  however, be concealed,  that the
truth of thefe difcoveries is ftrongly contefted by
very eminent chemifts; who infift, that the metal-
lic buttons produced in the experiments of Meffrs
Tondi  and  Ruprecht, arife entirely from the
manganefe and iron ofthe charcoal, or from fome
fimilar alloyage of materials from the crucibles or
tefts employed ; and  that they have no farther
pretentions to  be confidered as diftinft metals
than the fiderite, now known to be phofphorat-
ed iron, or than plumbago, or black-lead.
   Mr  Klaproth  a celebrated chemift at Berlin,
has  lately difcovered a new metal, to which he
gives the name of Uranium ;  and he diftinguiflies
its various mineral forms by  the generic term of
Uranite.  FJis numerous experiments on this fub-
ject, are publifhed  in Crell's Chemical Journal,
and  in the Annales de Chymie : and the follow-
ing  general account of the minerals, and of the
metal, was confidered as  proper to be given in
this place.
   The Uranite  occurs in feveral  forms, which
were formerly overlooked, by chemifts  and mi-
neralogifts, being  confidered as very poor ores
of  copper,  becaufe  they  moftly contain a  little
of  that  metal.  They are chiefly  found  near
Johanh-georgen Stadt  in Saxony, Salfeldt in
Thuringia,   and  Joachims-thal  in  Bohemia. 
OF  CHEMISTRY.
227
  Thefe  may  be divided into  three genera, the
  ochreous, the fpathiform, and the mineralized,
  or ore.  The ochreous, or uranite  ochre, called
  uraniie-oker, in the German language, is of a le-
  mon yellow colour, of various  fhades : and beino-
  frequently more or lefs mixed with iron ochre,
  its colour is thereby changed to various fhades
  of brown.   Sometimes  it is in a powdery ftate ;
  and  at other times it is caked together in maffes
  of different degrees of compa&nefs.  It is gene-
 rally found covering or adhering to  pieces of
  the  mineralized uranite.   The fpathiform,  or
  uranite fpar, called in German uranit-fpath, the
 chalkolith  of Mr Werner, is generally of a  deep
 grafs green colour, fometimes verging to  a filver
 white, and at other times to  a  light yellowifh
 green.  It is fometimes compact and irregular in
 its form ; and  is fometimes cryftallized in fmall
 fhining fquare and tranfparent tables, which are
 occafionally  fo thick as  to  be almoft  cubes.
 Thefe cryftals are lamellated in the fracture, and
 feel foft to the touch.  They are often found in
 fpots, fcattered  over the  furface of micaceous
 fchift, granite, or a mixture of quartz and black
 uranite qre. Both the ochre and fpar diffclve en-
 tirely in nitric acid.   The mineralized, or uranite
 ore, called in German  uranit-erz, pech-blende, or
pech-erz, is of a dark black-brown colour.  It is to-
 lerably hard, has a greafy  luftre, breaks compact,
and is black where fcratched.   It is very heavy, 
228         ELEMENTS

the fpecific gravity being 7.500. It does not melt
in the fire by itfelf; but  is  reduced under  the
blow-pipe, with  the addition of phofphoric acid,
to a green viireous globule.   It diffolves  imper-
fectly in the acids, but  beft in  the nitrous,  the
diffolution being of a pale white-wine colour.
  Uranium, the metal procured from thefe mi-
neral fubftances, is even more difficultly fufed
than manganefe.   Its fpecific gravity is 6.440. It
is of a dark grey colour, becoming brown when
fcratched. Its brilliancy is flight: and it is rather
fof:, being eafily cut with a knife or file.   It dif-
folves very imperfectly in the fulphuric and mu-
riatic acids, but very readily, and with confider-
able evolution of heat, in nitric and nitro-muria-
tic acids. From this diffolution, its oxyd is preci-
pitated  of a yellow colour, by the pure alkalies ;
and  the precipitates are re-diffolved by an excefs
of alkali.  With the alkaline carbonats, the preci-
pitates are whitifh,  and reddifh brown when the
pruffiats are employed. Thefe oxyds do not melt
under the blow-pipe,  without addition: but with
foda and borax, they melt into a brown button ;
and with phofphoric acid the button is of a green
colour. 
O F  C II E M I S T RY.
22'j
              C H A P.   XVII.


Continuation of the Obfervations  upon  Salifiable
    Bafes, and the Formatie-n of Neutral Salts.


  IT is neceffary to remark, that earths and  al-
    kalies  unite  with  acids  to form neutral
falts without  the intervention of any  medium ;
whereas  metallic  fubftances  are incapable of
forming  this combination, without  being pre-
vioufly lefs or  more oxygenated.  Strictly fpeak-
ing, therefore, metals are not  foluble in acids,
but only metallic  oxyds.  Hence,  when a me-
tal is put into  an acid for folution, it is neceffary,
in the firft  place,  that it  become  oxygenated,
either by attracting oxygen from the acid, or
from  the water with which the acid is diluted ;
or, in other words, that a metal cannot  be dif-
folved in an acid,  unlefs  the oxygen, either of
the acid, or of the water mixed with it,  has a
ftronger affinity to  the metal than to the hydro-
gen or the acidifiable bafe ; or, what amounts to
the fame thin:;, that no  metallic diffolution can
take place, without a  previous  decompofition of
the water, or of the acid in which it is made. The
explanation of the principal  phenomena of mc- 
230
ELEMENTS
tallic diffolution depends  entirely on this fimple
obfervation, which was overlooked  even by the
illuftrious Bergman.
  The firft and moft ftriking of thefe phenome-
na is the effervefcence, or, to  fpeak lefs equivo-
cally, the difengagement of  gas,  which takes
place during the folution. In the folutions made
in nitric acid, this effervefcence is produced by
the difengagement of nitrous gas.   In folutions
with fulphuric  acid, it is either fulphurous  acid
gas or hydrogen gas, according as the oxydation
of the metal happens to be  made  at  the  ex-
pence  of the fulphuric acid  or  of  the  water.
As both nitric acid  and water are  compofed of
elements, which, when feparate, can only exift
in the gaffeous  form, at  leaft  in the common
temperature of the atmofphere,  it  is  evident,
that, whenever either of thefe is deprived of its
oxygen,  the remaining  element  muft inftantly
expand and affume the ftate of gas.   The effer-
vefcence is occafioned by this  hidden conver-
fion from the liquid to the gaffeous ftate.  The
fame decompofition, and confequent formation
of gas, takes place  when folutions of metals are
made in fulphuric  acid.   In general, efpecially
by the humid way,  metals do not attract all the
oxygen it contains. They therefore reduce it, not
into  fulphur, but  into fulphurous acid ;  and as
this acid  can only exift as gas in  the ufual tern- 
       OF  CHEMISTRY.        231

perature, it is difengaged, and  occafions effer-
vefcence.
  The  fecond obfervable phenomenon is, that,
when the metals have been previoufly oxydated,
they all diffolve  in acids without effervefcence.
This is eafily explained; becaufe, not having now
any  occafion for combining with oxygen,  they
neither decompofe the  acid nor the water, by
which decompofition, in the former  cafe, the
effervefcence is occafioned.
  A  third phenomenon, which  requires parti-
cular confideration, is, that none  of  the metals
produce effervefcence by  folution in oxygenat-
ed muriatic acid.  During this procefs, the me-
tal,  in the firft  place, carries  off the excefs of
oxygen from the oxygenated muriatic acid, by
which it becomes  oxydated,  and reduces the
acid to the ftate of  ordinary muriatic acid.  In
this cafe there is no production of gas ;  not that
the muriatic acid does not tend   to exift in the
gaffeous ftate in the common temperature, which
it does equally with the acids formerly mentioned,
but  becaufe this acid, which  otherwife  would
expand into gas, finds more water combined  with
the  oxygenated muriatic acid, than is neceffary
to retain it in the liquid form. Hence it does not
difengage like the fulphurous acid, but remains,
and quietly diffolves and  combines with the me-
tallic oxyd previoufly formed from its fupsrabun-
dant oxygen. 
232         E  L E M E  :i  T S

  The fourth phenomenon worthy of notice is,
that metals_are abfolutely infoluble in fuch acids
as have their bafes joined to oxygen by a ftrong-
er affinity than thefe metals are capable of ex-
erting  upon  that acidifying principle.   Hence
filver, mercury, and lead, in their metallic ftates,
are  infoluble  in muriatic acid ;  but, when previ-
oufly oxydated, they become readily foluble with-
out effervefcence.
  From  thefe phenomena it appears, that oxy-
gen is  the  bond of  union between  metals and
acids :  and from this  we are led to fuppofe, that
oxygen is contained in all fubftances which have
a ftrong affinity with acid. Hence it is very pro-
bable,  that the four eminently falifiable earths
contain oxygen, and that their capability  of u-
niting with acids is produced by the intermedia-
tion of that  element.  What  I have formerly
noticed,  relative to thefe  earths, viz. that they
may very poffibly be metallic oxyds, with which
oxygen has a ftronger affinity than with carbon,
and confequently are  not reducible by any known
means, is confiderably ftrengthened by the above
confiderations.
  All the acids hitherto known, are enumerated
in the following table. The firft column contains
the names ■ of the  acids,  according to the new
nomenclature, in Latin ; in  the fecond column,
the Englifh names,  according  to the fame no- 
OF  CHEMISTRY.
23d
menclature  are  placed ;  the  third contains the
bales  or radicals of thefe acids.
Table of all the known Acids.
Latin Names.
Englijh Names.
 10
 II
 32
 *3
 H
 lS
 \6
-7
18
•9
 Acidum fulphurofum  Sulphurous acid
 ----fulphuricum    Sulphuric
 ----phofphorofum   Phofphorous
 ----phofphoricum   Phofphoric
 ----muriaticum     Muriatic
 -------oxygenatum* Oxygenated muriatic
----nitrofum        Nitrous
----nitric um        Nitre
-------oxygenatum{ Oxygenated nitric
    Bafes.
> Sulphur
> Phofphorus

| Unknownf
}
Azot.
- carbonicum
- acetofum
■ aceticum
oxalicum
 tartarofum
Carbonic
Acetous
Acetic
Oxalic
Tartarous
Carbon
----pyro-tartarofum Pyro-tartarous
----citricum        Citric
----malicum        Malic
----pyro-lignofum   Pyro lignous
----pyrc-mucofum   Pyro-mucous
   Compound.
' See Obf. ift.
   * This term might  be changed for Acidum murioxicum,
 Murioxic acid.—T.
   t In a former note, Hydrogen is mentioned as the fuppofed
 bafe of this acid.—T.
   I This  might more conveniently be named Acidum nitrox*
icum, or Nitroxic acid.—T.
                         G2 
2J4
ELEMENTS
20
21
22
23
24
25
26
27
28
29
30
31
3Z
33
34
35
36
37
33
39
40
4>
42
43
44
 Latin Names.
Acidum gallicum
----  prufficum
   -  benzoicum
      fuccinium
----  camphoricum
---•  ladicum
----  faccho-la&icum
----  bombicum
----  formicum
----  febacium
----  boracicum
----  fluoricum
----  antimonicum
----  argenticum
.--- arfeniacum
----  bifmuthicum
----  cobaltk.um
—— cupricum
---- ftannicum
---- ferric um
.      manganic um
---- mercuricum f
---- molybdicum
 ---- nickolicum
 ---- auricum
Englijh Names.
 Gallic
 Pruflic
 Benzoic
 Succinic
 Camphoric
 Laftic
 Saccho-laftic
 Bombic
 Formic
 Sebacic
 Boracic
 Fluoric
 Antimonic
 Argentic
  Arfeniac*
  Bifmuthic
  Cobaltic
  Cupric
  Stannic
  Ferric
  Manganic
  Mercuric
  Molybdic
  Nickolic
  Auric
Bafes.
Compound,
See Obf.  2.
(Compound,
f See Obf. 3d.

t Unknown
  Antimony
  Silver
  Arfenic
  Bifmuth
  Cobalt
  Copper
  Tin
  Iron
  Manganefe
  Mercury
  Molybdena
  Nickel
  Gold.
  * This term differs a little from the general rule, in making
the name terminate in ac inftead of ic.  The bafe and acid are
diftinguifhed in French by Arfen/V  and hrknique; but,  as
the  f> liable ic was thought moft convenient for  the  Englifh
tranflation of the French ique, it became neceffiry to ufe this
fma.l deviation—T.
  4  Mr Lavoifier has Hydrargirique 1 but Mercurium being
Ufed for the metal or  bafe,  the name of this acid, as above,
is at leaft equally regular, and lefs harfh.—T. 
       OF  C HE MIS TRY.        235
    Latin Names.        Englijh Names.     Bafes.
45. Acidum platinicum    Platinic         Platina
46.----plumbicum      Plumbic         Lead
47.----tungfticum       Tungftic         Tungftein
48.----zincicum        Zincic           Zinc
        Obfervations on the foregoing Table.
   ift,  The  bafes or  radicals of the acids,  from
N° 11. to N° 19. inclufive, feem to be formed by
a combination of carbon and hydrogen :  and the
only difference appears to proceed from the dif-
fimilar proportions in which thefe elements com-
bine to form  the bafes  of thefe acids, together
with the different quantities of oxygen in their
acidification.  A connected feries of accurate ex-
periments is ftill wanted, to illuftrate this fubject
in a fatisfactory manner.
   2d,  The bafes or radicals  of the acids,  from
N° 20. to 16. inclufive, are hitherto very imper-
fectly  known.  We only know, that hydrogen
and carbon  are their principal elements,  and that
the pruffic acid contains likewife fome azot.
   2d,  The bafes of the acids 27, 28, 29, and all
others obtained  from animal fubftances, are ftill
very imperfectly known, and  require  farther in-
veftigation -, for they feem to confift of carbon,
hydrogen,  phofphorus, and azot, united  toge-
ther : but the particular proportions of thefe ele-
ments in each, and the degrees of oxydation, arc
unafcertained. 
 2j6       ELEMENTS

    In this lift, which  contains  48 acids, I have
 enumerated 17 metallic acids, hitherto very im-
 perfectly known*, but upon which Mr Berthol-
 let is about to publifh a  very  important  work.
 It cannot be pretended  that  all the acids  which
 exifl in nature, or rather all the  acidifiable ba-
 fes, are yet difcovered.   But on  the other hand,
 there  are  confiderable  grounds  for  fuppofing,
 that a more accurate inveftigation than has hi-
 therto been attempted, will  diminifh  the num-
 ber of the vegetable  acids, by fhewing, that fe-
 veral of thefe, at  prefent confidered  as diftinct
 acids, are only modifications  of others.   All that
 can be done,  in the prefent ftate  of  our know-
 ledge, is, to give  a view of chemiftry, as it really
'is,  and to eftablifh  fundamental  principles, by
 which fuch bodies as may be difcovered in future,
 may receive names, in conformity with  one uni-
 form fyftem.
   The known falifiable bafes, or  fubftances ca-
 pable of being converted into neutral  falts, by
 union with  acids,  amount to 24;  viz.  3  alkalies,
 4earths,  and   17  metallic  fubftances;  fo  that,
 in the prefent  ftate of chemical knowledge, the
 whole poffible number of neutral falts  amounts

   *  The lift might have been augmented by the probable a-
cids from the newly difcovered metals, mentioned in the ad-
ditional feftion of the former chapter.   It is not impoflible
that the bafes of the Boracic and Fluoric aci.ls may  here*
gfter be difcovered among thefe ne w metals.—T. 
OF  CHEMISTRY.
237
to 1152*.  This  number is  upon the fuppofi-
tion,  that the metallic acids are capable of dif-
folving other metals,  which is a new branch of
chemiftry, not hitherto inveftigated, upon which
depends  all  the metallic combinations named
vitreous.  There is reafon to believe,  that many
of thefe fuppofable  faline combinations are not
capable  of being formed, which  muft greatly
reduce the real  number  of neutral falts produ-
cible  by  nature and art.   Even  if we  fuppofe
the real number  to amount  only to five or fix
hundred  fpecies of poffible  neutral  falts, it is
evident, that,  were we to diftinguifh them,  after.
the manner ofthe older chemifts,  either by the
names of their firft difcoverers, or by terms de-
rived from the  fubftances  from which they are
procured,  we fhould at laft have fuch  a confu-
fion of arbitrary  defignations,  as no memory
could poflibly retain. This method might be to-
lerable in the early ages  of chemiftry,  or  even
till within thefe twenty years,  when  only about
thirty  fpecies of falts were known.   But,  in the
prefent times, when the  number is augmenting
daily,  when  every  new   acid gives us 24 or 48
new falts, according as  it is  capable of one or

  * This number excludes all triple  falts, or fuch as contain
more than one falifiable bafe, all the falts whofe bafes are over
or under faturated with acid, and thofe formed by the nitro-
murhtic  acid.—T. 
a38          ELEMENTS

two  degrees of oxygenation, a new method  is
certainly neceffary.   The method here adopted,
drawn from the nomenclature ofthe acids, is per-
fectly analogical;  and, following Nature in the
limplicity of her operations,  gives a natural and
eafy  nomenclature, applicable to every poffible
neutral  fait.
   In  giving names to the different acids, we
have exprefled the common property by the ge-
nerical  term  acid,  and have  difiinguifhed each
fpecies, by the name of its peculiar acidifiable bafe.
Hence  the  acids formed by the oxygenation  of
fulphur,  phofphorus,  carbon, &c. are calledy#/-
phuric  acid,  phofphoric acid,   carbonic acid, &c.
We  thought it proper, likewife,  to indicate the
different degrees of faturation with  oxygen, by
different terminations of the fame fpecific names:
Wherefore we diftinguifh between fulphurous and
fulphuric, and between phofphorous and phofpho-
ric acids, &c.
   By  applying  thefe  principles to the nomen-
clature of neutral falts, we ufe a common term
for all  the  neutral falts arifing from the combi-
nations of one acid,  and diftinguifh the fpecies,
by adding the name ofthe falifiable bafe.  Thus,
all the neutral falts having fulphuric acid in their
compofition,  are named fulphats; thofe formed
by the  phofphoric acid, phofphats,  &c.  The
fpecies being diftinguifhed by  the names of the
falifiable bafes, gives us fulphat of 'potafh, fulphat of 
OF  CHEMISTRY.
*39
foda, fulphat of ammoniac, fulphat of lime, fulphat
 of iron, &c.   As we are acquainted with 24 fali-
 fiable  bafes, alkaline, earthy,  and metallic, we
 have confequently  24  fulphats,  as  many phof-
 phats, and fo on through all the  acids.
    Sulphur is, however, fufceptible  of two  de-
 grees of oxygenation, the firft of which produ-
 ces fulphurous,  and the fecond, fulphuric  acid :
 and, as  the neutral falts produced by thefe two
 acids,  have different  properties, and are in  fact
 different falts, it  becomes  neceffary to  diftin-
 guifh thofe by peculiar  terminations.   We have
 therefore diftinguifhed  the  neutral falts  formed
 by the acids in the  firft or leffer degree of oxy-
 genation,  by  changing the  termination at into
 ite, as fulphites, phcfphites*, &c.   Thus,  oxy-

   * As all the fpecific names of the acids in the new nomen-
clature are adjeftives,  they would  have applied feverally to
the various falifiable bafes, without the invention of other
terms  with  perfect diftin&nefs.   Thus, fulphurous potajh,
and fulphuric potafh, are equally diftinft, as fulphite of potajh^
and fulphat of 'potajh s and have the advantage of being more
eafily retained in the memory, becaufe more naturally arifing
from the names of acids  themfelves, than the arbitrary ter-
minations adopted by Mr Lavoifier.  Thefe  propofed terms
are likewife  very readily and diftinftly exprefiible in Latin,
thus, Potafh, or rather, as  I  have formerly obferved, Lixa,
Sulphurofa, and Sulphurica, and are equally diftinclive with,
and more readily remembered than, the  Latin terms of the
new nomenclature,  Sulphis and Sulphas  Potajfa.—T. 
240
ELEMENTS
  genated  or acidified  fulphur, in its  two degrees
  of oxygenation,  is capable of  forming 48  neu-
  tral falts, 24 of  which are fulphites,  and  as ma-
  ny fulphats.   This is likewife  the cafe with  all
  the acids capable of two  degrees  of  oxygena-
  tion*.
    It were both  tirefome and  unneceffary  to fol-
  low thefe denominations through  ail the  varie-
  ties of their poffible applications.   It is enough
  to have given the method of naming the various
  falts,  which, when once  well  underftood,  is ea-
  fily  applicable  to every  poffible  combination.
  The  name  of the combuftible  and acidifiable
 body  being once  known,  the  names of  the  a-
 cid it  is capable  of forming, and of all the neu-
 tral combinations the acid is  fufceptible of en-

   * There  is yet a third degree of oxygenation of feveral
acids, as the oxygenated muriatic and oxygenated nitric  a-
cids.  The  terms applicable to  the neutral falts  refulting from
the union of thefe acids with falifiable bafes are fupplied by the
Author in the Second Part of this Work.  Thefe are form-
ed by prefixing the word oxygenated to the name of the fait
produced by the fecond degree  of oxygenation.  Thus, oxy-
genated marizt of potafh,  oxygenated nitrat of foda, Sec.   Or
if the change I have propofedin a former note, on the nomen-
clature of thefe two acids, be adopted, we Ihall have murioxic
ai.d nitroxic  potafh or lixa,  in Latin  Lixa murioxica, Trcna
nitroxica, initead of the much knger, and not  more  diftinc-
tive expreffons, Murias potajfee oxygenata, iSitras foda o>y-
ge:iata.—T. 
OF  CHEMISTRY.
241
 tering into, are moft readily remembered.  Such
 as require a more  complete  illuftration  of the
 methods in  which  the new nomenclature is ap-
 plied, will,  in the fecond Part of this book, find
 Tables which contain a full enumeration  of all
 the neutral falts,  and, in general, of all the pof-
 fible chemical  combinations, fo far as  is con-
 fiftent with the prefent ftate of our knowledge.
 To thefe I fhall fubjoin fhort explanations, con-
 taining the beft and moft fimple means of pro-
 curing the different fpecies of acids, and fome
 account of the general properties of the neutral
 falts they produce.
   I Ihall  not deny, that,  to render this work
 more complete, it would have been neceffary to
 add particular obfervations upon each fpecies of
 fait; its folubility in water and alkohol;  the
 proportions of acid  and  of  falifiable bafe in  its
 compofition j the  quantity of  its water of cryf-
 talizationj  the different degrees of faturation
 it is fufceptible of j  and  finally, the degree  of
 force or affinity  with which the acid adheres to
 the bafe.   This immefe  work  has  been already
 begun  by MefT. Bergman,  Morveau, Kirwan,
 and other celebrated  chemifts j  but is hitherto on-
 ly in a moderate ftate of advancement.   Even
 the principles upon which it is  founded  are not
perhaps fufficiently accurate.
                     Kk 
242         E,L E M E N T  S

   Thefe numerous details would  have fwelled
this  elementary  treatife  to much  too great a
fize i befides that,  to  have gathered th'e necef-
fary  materials, and to have  completed all the
feries of experiments  requifite, muft have re-
tarded  the  publication of this book for  many
years.   This is a  vaft field for employing the
zeal  and abilities  of young  chemifts,  whom I
would advife  to  endeavour  rather to do  well
than  to do much,  and to afcertain,  in the firft
place, the compofition of  the acids,  before en-
tering upon that of  the neutral falts.   Every  e-
difice which is intended to refift  the  ravages  of
time, fhould be  built upon a fure foundation:
and, in  the prefent ftate of chemiftry, to attempt
difcoveries  by experiments, either not perfectly
exact, or not  fufficiently  rigorous,  will  ferve
only  to interrupt its progrefs, inftead  of contri-
buting  to its advancement. 
OF  CHEMISTRY.
243
PART   II.
Of the Combination of Acids with Salifiable Bafes,
      and of the Formation of Neutral Salts.
         INTRODUCTION.


   IF I had  ftrictly followed the  plan at  firft
    laid down for  the  conduct, of this  work, I
would have  confined myfelf, in the Tables  and
accompanying obfervations which compofe this
Second Part, to fhort definitions  of the feveral
known acids, and abridged accounts of the pro-
ceffes by which they are obtainable, with a mere
nomenclature  or enumeration  of  the  neutral
falts which refult from  the combination  of thefe
acids with the various  falifiable bafes.    But I
afterwards found,  that the  addition  of fimilar
Tables of all the fimple fubftances  which enter 
H4
ELEMENT S
  into the compofition ofthe acids and oxyds, to-
  gether with the various poffible combinations of
  thefe elements, would add greatly to the utility
  of this work, without being any great increafe to
  its fize.   Thefe additions, which are all contained
  in the twelve firft fections of this Part,  and the
  Table annexed to thefe, form a kind of recapi-
%  tulation of the firft  fifteen Chapters of the Firft
  Part; the reft of the Tables and Sections contain
  all the faline combinations.
     It muft be very apparent, that,  in this Part of
  the Work, I  have  borrowed  largely from what
  has been already publifhed by Mr de Morveau
  in the Firft Volume of the Encyclopedie par ordre
  des Matieres.   I could hardly have difcovered
  a better  fource of  information,  efpecially when
  the difficulty of confulting books in foreign lan-
  guages is confidered.  I make this general ac-
  knowledgment on  purpofe to fave the trouble
  of references to  Mr dc Morveau's work, in the
   courfe of the following part of mine. 
OF  CHEMISTRY.
245
        TABLE OF SIMPLE SUBSTANCES.

  Simple fubftances belonging to all the kingdoms of Nature,
which may be confidered as the chemical elements of bodies.
Englifh.
Light


Caloric
Oxygen
Azot
New Names.
       Latin.
                              Correfpondent eld Names.

                              Light.
                              Heat,
                              Principle or element of heat.
                              Fire,  Igneous fluid,
                            _ Matter of fire and heat.
                            f Dephlogifticated air,
                            j Empyreal air,
                            j Vital air, or
                            ^Bafe of vital air.
                            f Phlogifticated air or gas,
                            I Mephitis, or its bafe.
                            f Inflammable ajr or gas, or
                            \  the bafe of inflammable air.

   Oxydable and Acidifiable fimple Subftances not metallic.
        New Names.             Correfpondent old Names.
Sulphur       Sulphqrum    Iti.. A„.«m«
r,, V «.        »l /■  u        > I he lame names.
Phofphorus     Phofphorum   J
r. ,           ^  ,          (The fimple elements of char-
Carbon        Carbonum     <     . *

Muriatic radical Murium
Fluoric radical  Fluorum      \ Still unknown.
Boracic radical Boracum
Caloricum
Oxygenum
Azotum
Hydrogen    Hydrogenurn
\
Oxydable and acidifiable fimple Metallic Bodies
 Antimony
 Arfenic
 Bifmuth
 Cobalt
 Copper
 Gold
 Iron
 Lead
 Manganefe
 Mercury
 Mplybdena
 Nickel
PI atina
New Names.	Correfpondent old Names	
Antimonium. "*		r Antimony.
Arfenicum		Arfenic
Bifmuthum		Bifmuth.
Cobaltum		Cobalt.
Cuprum	o	Copper. Gold.
Aurum	CO	
Ferrum	►tH	Iron.
Plumbum	60	Lead.
e Manganum		Manganefe.
Mercurium		Mercury.
A Molybdenum		Molybdena,
Nickolum		Nickel.
Platinum		w Platina,
 
246            ELEMENTS
Silver
Tin
Tungftein
Zinc
     New
 Englijh.
Lime

Magnefia
Barytes
Argill
Silex
Strontites
Argentum
Stannum
Tungftenum
Zincum
f   ) Tungftein.
)   (Zinc.
Salifiable fimple Earthy Subftances.
Names
   Latin.
   Calca

   Magnefia
   Baryta
   Argilla
   Silica
     Correfpondent old Names

f Chalk, calcareous earth,
\ Quicklime.
C Magnefia, bafe of Epfom fait,
\ Calcined or cauftic magnefia.
  Barytes, or heavy earth.
 Clay, earth of alum.
Silicious or vitrifiable earth.
Strontyta     Newly difcovered.
Sect. I.   Obfervations upon  the  Table of Simple
                   Subftances.

   The principal object of chemical experiments
is to decompofe  natural bodies, fo as feparately
to examine the different fubftances which enter
into their  compofition.   By confulting chemi-
cal fyftems, it will be found, that this fcience of
chemical  analyfis  has made rapid progrefs  in
our times.   Formerly  oil  and fait were confi-
dered  as elements of  bodies: whereas later ob-
fervation  and  experiment have  fhewn,  that  all
falts,  inftead of being fimple,  are compofed  of
an  acid united  to a bafe.   The bounds of  ana-
lyfis have been greatly  enlarged by modern dif-
coveries*.    The acids are fhewn to be compofed
  * See Memoirs  of the academy  for 1766, p. 671, and for
177*> P« 535-—A. 
        O F  C H E M I S T R Y.       147

of oxygen, as an acidifying principle'vcommon
to all, united in each to a  particular bafe.   I
have proved,  what Mr  HafTenfratz had before
advanced, that thefe radicals of the acids are not
all fimple  elements, many of them being,  like
the oily  principle,  compofed of hydrogen and
carbon.  Even the bafes of neutral  falts have
been proved, by Mr Berthollet, to be compounds ;
as he has fhewn,  that ammoniac is compofed  of
azot and hydrogen.
   Thus, as chemiftry advances towards perfec-
tion, by dividing and fubdividing,  it is impofli-
ble to fay where it is to  end :  and thefe things
we at prefent fuppofe fimple, may foon be found
quite otherwife.  All we dare venture to affirm
of any fubftance, is,  that it muft be confidered
as fimple in the prefent ftate of our knowledge,
and fo  far as chemical analyfis has hitherto been
able  to fhow.  We may even prefume, that the
earths muft foon ceafe to  be confidered as fimple
bodies.   They are the only bodies of the falifia-
ble clafs  which have no  tendency to  unite with
oxygen^   and  I am much  inclined to  believe
that  this proceeds from  their being already  fa-
turated  with that element.    If fo,  they will
fall to be confidered as compounds, confifting of
fimple  fubftances,  perhaps metallic, oxydated to
a certain  degree.   This is  only hazarded as a
probable conjecture :  and I truft the reader will 
a48         ELEMENTS

take care not to confound what I have related as
truths,  fixed on  the firm bafis of obfervation
and experiment, with mere hypothetical fpecula-
tions.
  The  fixed alkalies, p6tafh,  and foda,  are o-
mitted in the foregoing Table,  becaufe they  are
evidently compound fubftances*; though we  are
ignorant  as  yet what are the elements they  are
compofed of.
  * For the fame reafon, Calca, Magnefia, and Baryta, ought
to have been omitted in this edition, as has been explained in
p.  219.  But, though the tranflator has taken the freedom to
make feveral obfervations and fome additions, he has not ven-
tured to make any alterations.   The latter is the exclufive5
province of the author.—T. 
OF   CHEMISTRY.
249
Table of compound or oxydable and acidifiable bafes*
Oxydable or acidifiable 1
bale?, from the mineral
kingdom.
Oxydable or acidifiable
hydro-carbonous or car-
  Names of the Radicals.
Nitro  muriatic  radical,* or
   bafe  of  the acid formerly
   called aqua regia.
"Tartarous  radical or bafe.
 Malic
 Citric
 Pyro-lignous
 Pyro-mucous
1     11        i-  1   j Pyn>tartarou9
bono-hydrous  radicals, <| n;vol „
from the vegetable king-
dom.
Oxydable or acidifiable
radicals  from  the  ani-
mal  kingdom,   which,
moftly   contain   azot,]
and   frequently  phof-  J T . , .
phorus.                   " 'c
1                       j^rruflic.
Oxalic
Acetous
Succinic
Benzoic
Camphoric
Gallic
Lattic
Saccholaclk
Formic
Bombic
  u

f o
  Note.—The Radicals from the vegetable kingdom are con-
verted by a firft degree of oxygenation into vegetable oxyds*
fuch as fugar, ftarch, and gum or mucus:  thofe of the ani-
mal kingdom by the fame  means form animal oxyds, as
lymph,  &c.—A.
  * This, for the prefent, may be named  Azo-muria, until
the radical of muriatic acid be difcovered ;  or, at leaft,  till
the difcovery of hydrogen being that radical be unqueftion-
ably afcertained.—T. 
250
ELEMENTS
Sect. II.—^Obfervations upon the  Table of Com-
               pound Radicals.

  The older chemifts being unacquainted with
the compofition of acids, and not fufpecting them
to be formed by a peculiar radical or bafe  for
each, united to an acidifying principle or element
common to all,, could not confequently give any
name to fubftances of which they had not themoft
diftant idea.  We had, therefore, to invent a new
nomenclature for this  fubject,  though we were
st the fame time fenfible that this nomenclature
muft be fufceptible of great modification, when
the nature ofthe compound radicals fhall become
better underftood *.
  The compound oxydable ajid  acidifiable ra-
dicals  from the vegetable and animal kingdoms,
enumerated in the foregoing table, are not hi-
therto reducible to fyftematic nomenclature ; be-
caufe their exact analyfis  is as yet unknown.
We only know in general,  by fome experiments
of my own,  and fome made by Mr Haffenfratz,
that moft  of the vegetable acids,  fuch as  the
tartarous,  oxalic, citric,  malic, acetous, pyro-
tartarous,  and pyro-mucous, have radicals com-
pofed  of  hydrogen and  carbon,  combined in

   * See Part I. Chap. XI. upon this fubject.—A. 
OF CHEMISTRY.
2.5*
fuch a way as to form fingle bafes ;  and  that
thefe acids only differ from each  other by the
proportions in which thefe two fubftances  enter
into the compofition of their  bafes, and by the
•degrees of oxygenation which thefe bafes have
received.  We know farther, chiefly from the
experiments of Mr Berthollet, that the radicals
from the  animal kingdom, and even  fome * of
thofe from vegetables, are of a more compound
nature ;  and,  befides hydrogen and carbon, that
they often  contain azot,  and  fometimes phof-
phorus.   But we are not hitherto poffeffed of
fufficiently accurate experiments for calculating
the proportions  of thefe feveral fubftances.  We
are therefore forced, in the manner of the older
chemifts, ftill  to name thefe acids  after the fub-
ftances from which they  are procured.  There
can be little doubt, that  thefe names will be laid
afide, when our  knowledge of thefe fubftances
becomes  more  accurate  and  extenfive;  the
terms,  hydro-carbonous,  hydro-carbonic, carbono-
hydrous, and carbono-hydric, * will then become
fubftituted for thofe we now employ,  which will
 then only remain as teftimonies of the imperfect
 ftate in which this part of chemiftry was tranf-
 mitted  to us by our predeceffors.

   * Sec Part I. Chap. XI.  upon the application  of thefe
 names according  to the proportions of the two ingredients. 
252
ELEMENTS
   It is evident, that the oils, being compofed of
hydrogen and carbon combined,  are  true  car-
bono-hydrous or hydro-carbonous radicals : and,
indeed, by adding oxygen, they are convertible
into vegetable acids  and  oxyds,  according to
their degrees of oxygenation.  We cannot, how-
ever, affirm, that oils enter in their entire ftate
into the  compofition  of vegetable oxyds  and
acids.   It is poffible,  that they  previoufly lofe a
part either of  their hydrogen and carbon;  and
that thd remaining ingredients no longer exift in
the proportions necelfary to conftitute oils.  We
flill require farther experiments to elucidate thefe
points.
   Properly fpeaking, we are only acquainted with
one compound radical from  the mineral king-
dom, the nitro-muriatic, which is formed by the
combination of azot  with the  muriatic radical.
The other compound  mineral acids  have been
much lefs attended to, from their producing lefs
ftriking phenomena.
Sect. III.—Obfervations upon the combination of
   Light and Caloric with different Subftances.

  I have not conftructed any table  of the com-
binations of light and caloric  with the various
fimple  and compound  fubftances; becaufe our 
OF  CHEMISTRY.
253
 conceptions of the nature of thefe combinations
 are not hitherto fufficiently  accurate.    We
 know in general, that  all bodies in nature are
 imbued,  furrounded, and penetrated in every
 way with caloric, which fills up every interval
 left between  their particles  ;  that, in  certain
 cafes, caloric becomes fixed  in bodies,  fo as to
 conftitute  a part even  of their folid fubftance;
 though it more  frequently acts upon them with
 a repulfive  force, from which, or from its ac-
 cumulation in  bodies to a greater or  leffer de-
 gree,  the  transformation of folids into fluids,
 and of fluids to  aeriform elafticity, is entirely
 owing.  We have employed the generic  name
gas to indicate this aeriform ftate of bodies,  pro-
 duced by a fufficient accumulation of caloric;
 fo that, when we wifh  to  exprefs the aeriform
 ftate of muriatic acid,  carbonic acid, hydrogen,
 water, alkohol, &c. we do it by adding the word
gas to their  names;  thus muriatic acid gas, car-
bonic acid gas, hydrogen gas,  aqueous gas, al-
kohol gas, &c.
  The  combinations of light, and its  mode of
acting upon different bodies,  are ftill lefs known
than  thofe of caloric.   By the experiments  of
Mr Berthollet, it appears to have great affinity
with  oxygen, is fufceptible of combining with
it,  and contributes  with  caloric to change it
into the ftate  of gas.   Experiments  upon  ve-
getation give reafon to believe,  that  light com- 
254
ELEMENTS
bines with certain parts of vegetables ;  and that
the green of their leaves, and  the various co-
lours of their flowers, are chiefly owing to this
combination.  This much is certain,  that plants
which grow in  darknefs, are  perfectly  white,
languid, and unhealthy ;  and that to make them
recover vigour,  and to acquire their natural co-
lours, the direct influence of light is abfolutely
neceffary.   Somewhat fimilar  takes place even
upon animals.   Mankind degenerate to  a cer-
tain degree when  employed in fedentary ma-
nufactures,  or from living in crowded houfes,  or
in the narrow lanes of large cities; whereas they
improve in their nature and conftitution in moft
ofthe country labours which are carried on in
the open air.
   Organization, fenfation, fpontaneous motion,
and all the  operations of life,  only exift at the
furface ofthe earth, and in places expofed to the
influence  of light.   Without  it nature  itfelf
would be lifelefs and inanimate.  By means of
light, the benevolence of the  Deity hath  filled
the furface ofthe earth with organization, fen-
fation, and intelligence.  The  fable of Promo-
theus might perhaps be confidered  as giving a
hint  of  this philofophical  truth,   which  had
even prefented itfelf to the knowledge of the an-
cients.
   I have intentionally avoided  any  difquifitions
relative to  organized bodies in this work,  for 
To  face   Page  255
Names of the
 Simple Sub-
 ftances.
              Caloric   -
              Hydrogen

              Azot

   Combina- j Carbon   .
tions of oxy- I
genwithfim-v Sulphur
              Phofphorus
              Muriatic
pie non-me
tallic fub
fiances.
Firft degree of oxygenation.
TABLE   of  the   Binary  Combinations  of  Oxygen  with  fimple  Subftances,___________
                                                                                                        I       'Fourth degree of oxygenation.
New Names.
Old Names.
Second degree of oxygenation.
Third degree of oxygenation.
New Names.
1 Old Names.
New Names.
  Oxygen gas
  Water *.
  Nitrous oxyd, or  bafe of
1    nitrous  gas
1'Oxyd of  carbon,  or car-
i   bonic oxyd
  Oxyd of fulphur
Vital or dephlogiiticated
  air
Oxyd of phofphorus
■0
(-'':$*i
          ra* \ Muriatic oXyd

Fluoric  radi-|Flu0ricoxyd    .

Boracic  radi- J ^^ Qxyd

               Grey oxyd of antimony

               Oxyd of filver
               Grey oxyd of arfenic  -
               Grey oxyd of bifmuth
               Grey oxyd of cobalt
   cal
"" Antimony

 Silver -
 Arfenic
 Bifmuth
 Cobalt
   Combina-
tions of oxy-
gen with  the J
fimple metal-
lic fubftan-
cesf.
Copper

Tin    -

Iron
Manganefe

Mercury

Molybdena
Nickel  -
Gold   -
Platina  -
Lead

Tungftein

Zinc
i
Brown oxyd of copper

Grey oxyd of tin

Black oxyd of iron

Black oxyd of  manganefe

Black oxyd of Mercury


Oxyd of molybdena

Oxyd of Nickel    - i

Yellow oxyd of gold  -

Yellow oxyd of platina

Grey oxyd of lead   -

Oxyd of Tungftein    -

Grey oxyd of zinc  . ;
  Nitrous gas or air

  Unknown
  Soft fulphur
(' Refiduum from the com-
l   buftion of phofphorus

  Unknown

  Unknown

  Unknown

  Grey calx of antimony

  Calx of filver
  Grey calx of arfenic  -
  Grey calx of bifmuth -
  Grey calx of cobalt  -

  Brown calx of copper

  Grey calx of tin

  Martial ethiops
 Nitrous acid

 Carbonous acid
 Sulphurous acid
'Phofphorous acid »

 Muriatous acid

 Fluorous acid

 Boracous acid
Smoakiifg nitrous acid

Unknown
Sulphureous acid
X
; Volatile acid of phofpho- | Phofphoric acid

                          Muriatic acid

  Unknown

  Unknown
White oxyd of antimony j

White oxyd of arfenic
White oxyd of bifmuth
White calx of antimony
  diaphoretic antimony

White jcfx of arfenic
White calx of bifmuth
Nitric acid

Carbonic acid
Sulphuric acid
"I
■J
Fluoric acid

Boracic acid

Antimonic acid

Argentic acid
Arfeniac acid
Bifmuthic acid
Cobaitic acid
j Blue and green oxyds of | Blue and} green  calces of ( QUpT[c acjd
1.   copper                3   cojj>per       -        3
  „...      ,  f„.         f White calx  of tin,  or 7 qtqnn:r „_• j
  White oxyd of tin        )   pity* Af tin    -      | tannic acid

f Yellow and  red oxyds °f 7 0chre an d ruft of iron
1.   iron       -          (
                                                                         Ferric acid

Black calx of manganefe  White oxyd of manganefe  White cilx"of manganefe J Manganic acid

Ethiops mineral J
                         rTurbith mineral, red pre- )
S Yellow and red oxyds of)   cipitate, Calcined mer- ?
Calx of molybdena

Calx of nickel

Yellow calx of gold

Yellow calx of platina

Grey calx of lead

Calx of tungftein

Grey calx of zinc
mercury
Red oxyd of gold
:■ YdW and red oxyds ofn Mafficotandminium
(    lead     -     -      j
                          Mercuric acid
l'   cury, precipate/<?r/£   J
                          Molybdic acid
                         t Nickolic acid
■ • Red c4 Of gold, purple  {Auric acid
\   precipitate of Caffius.
                          Platinic acid
                          Plumbic acid

                          Tungftic acid

i  Wphohfx ofzinc'pom" ]Zincic acid
Old Names.
New Names.
I  Pa!e> or. not fm0aJk- \ Oxygenated nitric acid
1    ing nitrous acid   \]
  Fixed air
  Vitriolic acid
  Phofphoric acid

  Marine acid

  Unknown till lately

( Homberg's  fedative
|   fait
Acid of arfenic -
Acid of molybdena
Acid of tungftein
Oxygenated carbonic acid
Oxygenated fulphuric acid

Oxygenated phofphoric acid

Oxygenated muriatic acid \ DepWogifticated
                        I   marine acid
OJd Names.
Unknown

Unknown
Unknow n
Unknown
Oxygenated arfeniac acid
Unknown
Oxygenated molybdic acid
Oxygenated tungftic acid
Unknown
Unknown
* Only one  deeree of oxygenation of hydrogen is hitherto known —A
+  As  all  the  metals   in  the oxyd  ftate,  are capable  of acting  in combinations in a fimilar manner wi:h i Ikalies and earths,  and as  the laft, though  difcovered  to be compounds, are in the new nomenclature,
                                               be very  convenient to  diftinguifh the oxyd ftate of each m< tal
reguline""ftate," 'and  Antimonia  might indicate the| oxyd ftate in general ;  any farther diftinftion ofthe oxyds  miy  e formed as  in the table
new nomenclature,  and would fhorten language without introducing  any  ambiguity  of expreilion.—T.
                                             " mercury ;   this fhould  have been  called,  for  the old name,  bljrckjprecipitate of mercury.—T
denominated by  feminine  Latin terms,  it would
    "me ftate,  and  Antimonic  might indicate th>
     nomenclature,  and would fhorten language v
     t  Ethiops  mineral is the black fulphuret of
n general,  from its reguline ftate,  fimply by  changing the gender;  thus Antimoniu* is the  fimple or
                          This propofed alteration is in perfect cjonformity with the principles of the 
t 
        OF  CHEMISTRY.      255

which reafon the phenomena of refpiration, fan-
guifkation, and animal heat, are not confidered.
But I hope,  at fome future time, to be able to
elucidate thefe curious fubje&s.

Sect. IV.—Obfervations upon  the  Combinations
     of Oxygen with the fimple  Subftances.

   Oxygen forms almoft a  third part of the mafs
of out atmofphere ; and is confequently one of
the moft  plentiful fubftances  in nature.   All
animals and vegetables  live  and grow in  this
immenfe magazine of oxygen gas :  and from it
we procure the greateft part of what we employ
in experiments.  So great  is  the reciprocal  affi-
nity between this element and  other fubftances,
that we cannot procure it entirely difengaged
from combination.  In the atmofphere, it is uni-
ted with caloric, in the ftate of oxygen gas :  and
this again is mixed v/ith about twice its weight
of azotic gas.
   Several conditions  are  requifite to  enable a
body to become oxygenated,  or to  permit oxy-
gen to enter into combination  with it.  In the
firft place,  it is neceffary  that the particles of
the body to be oxygenated (hall have  lefs reci-
procal  attraction with each other, than  they
have for the oxygen- which otherwife  cannpt
pofiibly combine with them.  Nature,  in  this
cafe, may be ailifted by art;  as we have it in ou 1 
256        ELEMENTS

power to  diminifh the attraction of the parti-
cles  of bodies,  almoft at  will, by heating them,
or, in other words, by introducing caloric  into
the interftices between their particles:  and, as
the attraction of thefe particles for each other
is dimiriifhed  in  the inverfe ratio of their dif-
tance, it is evident, that there muft be a certain
point  of diftance of particles  w.hen the affinity
they poffefs with each other becomes lefs  than
that they have  for oxygen, and at which  oxy-
genation muft neceffarily take place,  if oxygen
be prefent.
   We can readily conceive, that the  degree of
heat at which this phenomenon begins,  muft be
different in different  bodies.  Hence, on  pur-
pofe to oxygenate  moft  bodies, efpecially the
greater part of the fimple fubftances,  it is  only
neceffary  to expofe them to the influence of the
air of the  atmofphere, in a convenient degree of
temperature.   With refpeel: to lead, mercury,
and tin, this requires to be but a little  higher
than  the medium  temperature  of  the earth.
But it requires a more  confiderable  degree  of
heat to oxygenate iron,  copper, &c.  by the dry
way,  or when this operation is  hot  affifted by
moifture.  Sometimes oxygenation takes  place
with great rapidity, and is accompanied by  great
fenfible heat, light, and flame ; fuch is the  com-
buftion of phofphorus  in atmofpheric air, and
of iron in c::ygen gas.   That of fulphur is lefs 
OF  CHEMISTRY.
*57
rapid : and the oxygenation of lead, tin, and moft
of the metals, takes place vaftly flower, and con*
fequently the difengagement of caloric, and more
efpecially of light, is hardly fenfible.
   Some fubftances have fo ftrong an affinity for
oxygen,  and combine  with it in fuch low de-
grees of temperature, that we cannot  procure
them in their unoxygenated  ftate ;  fuch is  the
muriatic acid, which has not hitherto been  de-
compofed by art *, perhaps even not by nature,
and which confequently has only been found in
the ftate of acid.  It is probable that many other
fubftances of the mineral kingdom are neceffa-
rily  oxygenated in the common temperature of
the atmofphere; and that,  being already fatu-
rated with  oxygen, their farther  a&ion upon
that element  is  thereby prevented.
   There are other means of oxygenating fimple
fubftances, befides expofure to air in a certain
degree of temperature ; fuch as by placing them
in contact with metals combined with  oxygen,
and which have little affinity with that element.
The red oxyd of mercury is one of the beft fub-
ftances  for  this purpofe, efpecially with bodies
which do not combine with that metal.  In this
oxyd, the oxygen is united with very little force

                    Kk

   * The real or fuppofed difcavery of the bafe of this <ic!4
has been mentioned in fome former notes.-*~T. 
2$S        E  L E M E NT S
to the metal, and can be driven out by a degree
of heat only fufficient to make glafs red  hot:
wherefore, fuch bodies as are capable of uniting
with oxygen, are readily oxygenated, by means
of being  mixed with red oxyd of mercury, and
then moderately heated.  The fame effect may
be, to a certain degree, produced by means of
the black oxyd of  manganefe, the red oxyd of
lead, the  oxyds of filver, and by moft of the me-
tallic oxyds, if we only take care to choofe fuch
as have lefs affinity with oxygen than the bodies
they are meant to oxygenate ; all the  metallic
reductions and revivifications belong to this clafs
of operations,  being nothing more  than oxy-
genations of carbon,  by  means  of the feveral
metallic oxyds.  The carbon of the  charcoal
employed for  this  reduction, combines with;
the oxygen  and with caloric, and  efcapes in
form of carbonic acid gas;  while the metal re-
mains  pure  and revivified, or deprived of  the
oxygen which  before combined with it in  the
form of oxyd.
   All combuftible  fubftances may likewife be
Oxygenated  by means of mixing them with ni-
trat of potafh or of foda, or  with oxygenated
muriat of potafh, and fubjecting the mixture to
a certain  degree  of heat.   The oxygen, in this
cafe, quits the nitrat or  the muriat, and  com-
bines with the combuftible  body.  This fpecies
of oxygenation requires to  be performed with 
         OF  CHEMISTRY.     259

extreme caution, and only with very fmall quan-
tities ;  becaufe, as the oxygen  enters into the
compofition of nitrats, and  more efpecially of
oxygenated muriats,  combined with almoft "as
much caloric as is  neceffary  for  converting it
into oxygen gas, this immenfe quantity of calo-
ric  becomes fuddenly free, the inftant of the
combination of the oxygen with  the combufti-
ble body, and produces fuch violent explofions
as are perfectly irrefiftible.
   By the humid way we can oxygenate moft
combuftible bodies,  and  convert moft of the
oxyds  of the  three  kingdoms  of nature into
acids.   F05, this  purpofe we chiefly  employ
the nitric acid, which has a very flight hold
of  oxygen, and quits it readily to. a  great
number of bodies, by the afliftance of a gentle
heat.  The oxygenated muriatic acid may  be
ufed for feveral operations of this kind, but not
in them all.
   I give the name of binary to the combinations
of oxygen with the fimple fubftances, becaufe in
thefe only two elements are combined.   When
three fubftances are united in one combination I
call it ternary ; and quaternary when the combi-
nation confifts of four fubftances united. 
26©
ELEMENTS
Table of the  Combinations  of  Oxygen  with  thp
                 Compound Radicals.
"Names ofthe Radi-
      cals.
Nitro-muriatic ?
radical        3
        #
Tartaric
Malic
Citric

Pyro-lignous

Pyro-mucous
Pyro-tartarous
Oxalic

Acetic

Succinic
Benzoic
Camphoric

Gallic
      *#

Lactic
Saccholadlic
Formic
Bombic
Sebacic
Lithic

Pruflic
      Names of the refulting /tcids.
New Nomenclature.   Old Nomenclature*

Nitro-muriaticacid Aqua regia.
Tartarous acid    Unknown till lately.
Malic acid       Ditto.
Citric acid       Acid of lemons.
■r,    ..        ».  CEmpyreumatic a-
ryro-hgnous acid  <    -Ac     j
 1    °           f_   cid or wood. ■
Pyro-mucous acid Empyr. acid of fug.
Pyro-tartarous acidEmpyr.acid of tartr.
Oxalic acid       Acid of forrel.
 f A         .,    K Vinegar,or acid of
 1 Acetous acid    •<    .6
                  (   vinegar.
                  Radical vinegar.
                 Volatile fait of amber
                 Flowers of Benzoin,
                 Unknown till lately.
                  CThe  aftringent
                  (_   prin. ofvegt.
 I. Acetic acid
Succinic acid
Benzoic acid
Camphoric acid
Gallic acid
Laftic acid
Sacchola&ic acid
Formic acid
Bombic acid
Sebacic acid
Lithic acid
Pruflic acid
Acid of four whey.
Unknown till lately.
Acid of ants.
Unknown till lately.
Ditto.
Urinary1 calculus.
 C Colouring  matter
 \  of Pruffian blue.
   * Thefe radicals by a firft degree of oxygenation form ve*
getable oxyds, as fugar, ftarch, mucus, &c.—A.
   ** Thefe radicals by a firft degree of oxygenation form
the animal oxyds, as lymph, and part of the  blood, animal
lecretions, &c.—A. 
OF  CHEMISTRY.
261
Sect. V.—Obfervations upon the Combinations of
      Oxygen with the Compound Radicals.

  I publifhed a new theory of the nature and
formation of acids in the Memoirs of the  Aca-
demy for 1776,  p. 671. and 1778, p.  535, in
which I concluded, that the number  of  acids
muft be greatly larger than was  till then  fup-
pofed.  Since that time, a new field of inquiry
has been opened to chemifts:  and, inftead of
five or fix acids,  which were then known, near
thirty new acids have been difcovered, by which
means the number of known neutral falts has
been  increafed  in  the  fame proportion.   The
nature of the acidifiable bafes. or radicals of the
acids, and the degrees of  oxygenation they are
fufceptible of, ftill remain  to be inquired  into.
I have already fhown, that almoft all the oxyd-
able and acidifiable radicals from the mineral
kingdom are fimple; that, on the contrary, there
hardly exifts any radical in  the  vegetable,  and
more  efpecially in the animal kingdom, but is
compofed of at leaft  two fubftances, hydrogen
and carbon ;  and that azot and phofphorus are
frequently united to thefe,  by  which we  have
compound radicals of two, three, and four bafes
or fimple elements united- 
262
ELEMENTS
  From thefe obfervations, it appears, that the
vegetable and animal oxyds and acids may dif-
fer  from each other in three feveral ways; ac-
cording to the number of fimple acidifiable ele-
ments of which their radicals are compofed ; ac-
cording to the proportions in which thefe are
combined together; and according to their dif-
ferent degrees of oxygenation.  Thefe circum-
ftances  are  more  than  fufficient to explain the
great variety which nature  produces in  thefe
fubftances.  It is not at all furprizing, after this,
that moft of the vegetable acids are convertible
into each other; nothing more being requifite
for this purpofe, than  to change the propor-
tions of the hydrogen and carbon in their com-
pofition, and  to oxygenate them in a greater or
leffer degree.   This has been done by Mr Crell
in fome very ingenious experiments, which  have
been verified and extended by  Mr Haffenfratz.
From thefe it  appears, that  carbon and hydro-.
gen, by a firft  oxygenation, produce tartarous
acid, oxalic acid by a fecond degree, and ace-
tous or acetic acid by a third, or higher oxyge-
nation ; only, that carbon  feems to exift in a
rather fmaller proportion in the acetous and ace-
tic acids.   The citric and malic acids differ little
from the preceding acids.
   Ought we then to  conclude, that the oils are
 the radicals of  the vegetable and animal acids ?
 I have already expreffed  my  doubts upon this 
         OF  CHEMISTRY.     263

fubject:  For, although the  oils appear to be
formed of nothing but hydrogen and carbon,
we do not know if thefe are in the precife pro-
portion neceffary for conftituting the radicals of
the acids;  and, fince  oxygen enters  into  the
compofition of thefe acids equally with hydro-
gen and carbon, there is no more reafon for fup-
pofing them to be compofed of oil rather tjian
of water or of carbonic acid.  It is true that they
contain the materials neceffary for all thefe com-
binations ;  but then thefe do not take place in
the common temperature of  the  atmofphere.
All the three elements  remain combined  in a
ftate of equilibrium,  which is readily deftroyed
by a temperature only a little above that of boil-
ing water *.
* See part I. Chap. XII. upon thisfubjeft.—A; 
264
ELEMENTS
Table of the Binary Combinations  of Azot with
                the Simple Subftances.
   Simple
 Subftances.
Caloric

Hydrogen

Oxygen
Carbon


Phofphorus

Sulphur
Compound
 radicals
Metallic fub-
   ftances.

L?me
Magnefia
Barytes
Argill
Potafli
Soda
        Refults of the Combinations.
  New Nomenclature.  Old Nomenclature.
  *   .•        A       C Phlogifticated air,
  Azotic gas.orAzogas 1     *• _
         6  '      °   I   or Mephitis.

  Ammoniac, Ammona   Volatile alkali.
{"Nitrous oxyd        Bafe of nitrous gas.
J Nitrous acid         Smoking nitrous acid'
"l Nitric acid          Pale nitrous acid.
(^Oxygenated nitric acid. Unknown.
 rThis combination  is hitherto  unknown.
 1   Should it ever be difcovered, it will be
 I   called, according  to  the principles of
 j   our nomenclature, Azuret of Carbon.
 J   Carbon diffolves in azotic gas,  and
 ^   forms carbonated azotic gas.
   Azuret of phofphorus.  Still unknown.
   {Azuret of Sulphur.  Still unknown.  We
     know that fulphur diffolves  in  azoti«p
     gas, forming fulphurated azotic gas.
 f Azot  combines with carbon  and bydro-
 j,   gen, and  fometimes with phofphorus,
 i   in the compound oxydable and acidifia-
 I   ble bafes; and is generally contained in
 l_   the radicals of the animal acids.
 TSuch combinations are hithertounknown.
■ J   If ever difcovered, they will  form me-
 J   tallic azurets, as azuret of gold,  of fil-
 (_  ver, &c.
 1
 1 Entirely unknown;   If ever  difcovered,
 |>   they will form azuret of lime, azuret of
 {   magnefia, &c.

J
  Note. The Latin term, in the newmomenclature,lieretranf-
lated Azuret, is Azuretum. The French of Mr. Lavoifier is
Azure.   I preferred taking the Englifh from the Latin,  be- 
         OF" CHE MTS TRY.      265

Sect. VI.—Obfervations upon the Combinations of
        Azot with the Simple Subftances.

   Azot is one of the moft abundant elements ;
combined with caloric it  forms azotic gas,  or
mephitis,  which compofes nearly tWo-thirds  of
the atmofphere.   This element is always in the
ftate of gas in the ordinary preffure and tempe-
rature, and no degree of compreflion or of cold
has been hitherto capable  of reducing  it either
to a folid or liquid form.   This is likewife one
of the effential conftituent elements of animal
bodies in which it is combined with carbon and
hydrogen,  and  fometimes with phofphorus ;
thefe are united together  along with  a certain
portion of oxygen, by which they  are formed
into'oxyds or acids, according  to the degree of
oxygenation.  Hence the animal fubftances may
be varied, in the fame way with vegetables, in
three different manners ;  according to  the num-
ber of elements which enter into  the  compofi-

caufe it is thus more diftincl: from other terms :  the French
terms Azure, Sulphure, Phofphure, are not fufficiently dif-
tiDguifhable in Englifh, from Azure, a colour, Sulphur, and
Phofphor, which is fometimes  ufed for Phofphorus ;  but
Azuret, Sulphuret, Carburet, and Phofphuret, which are
tranflated from Azuretum, Sulphuretum, Carburetum,  and
Phofphoretum, both anfwer the purpofe of the new  nomeo-   •
clature completely, and run no  hazard of occafioning  any
 miftake.—T.
LI 
266
ELEMENTS
tion  of the bafe or radical; according to the
proportion of thefe elements; and, according
to the degrees of oxygenation.
   When  combined with  oxygen, azot forms
the nitrous and nitric oxyds and acids; when
with hydrogen,  ammoniac is  produced.   Its
combinations with the other fimple elements are
very little known ; to thefe we give the name of
Azurets,  preferving the termination in uret for
all unoxygenated compounds.  It is extremely
probable that all  the alkaline fubftances  may
hereafter be found to belong to  this genus  of
azurets.
   The azotic gas may be procured from atmo-
fpheric air, by abforbing the oxygen gas which
is mixed  with it by means of a folution of ful-
phuret of potafh,  or fulphuret of lime.  It re-
quires  twelve or  fifteen days to complete this
procefs, during which time the furface in  con-
tact  muft  be  frequently renewed by agitation,
and  by breaking the pellicle which forms on the
top of the folution.  It may likewife be procur-
ed by diffolving animal fubftances in  dilute  ni-
tric  acid very little heated.  In  this operation
the azot is difengaged in  form  of gas, which
muft be received under bell-glaffes filled  with
water,  in the  pneumato-chemical apparatus.
We may procure this gas by deflagrating  nitre
with charcoal,  or any  other combuftible fub-
ftance ; when with charcoal, the azotic gas is 
         OF  CHEMISTRY.     267

mixed with carbonic  acid gas, which  may be
abforbed by a folution of cauftic alkali, or by
lime water;  after which the azotic gas remains
pure.  We can procure it in a fourth  manner
from combinations of ammoniac  with  metallic
oxyds, as pointed out  by Mr de Fourcroy.  The
hydrogen of the  ammoniac combines  with the
oxygen of the oxyd, and forms water; while
the azot being left free efcapes in form of  gas.
  The combinations of azot were but lately dif-
covered.  Mr Cavendifh firft obferved it in ni-
trous gas and acid, and Mr Berthollet in ammo-
niac and the pruflic  acid.  As no  evidence of
its decompofition has hitherto appeared, we are
fully entitled to confider azot as a fimple ele-
mentary fubftance. 
268
ELEMENTS
Table of the Binary  Combinations of Hydrogen
               with Simple Subftances.
   Simple
  Subftances.
Caloric
Azot
Oxygen
Sulphur

Phofphorus

Carbon
Metallic fub-
  ftances, as
  iron, &c.
            Refulting Compounds.
 New Nomenclature.         Old Names.
  Hydrogen gas           Inflammable air.
  Ammoniac              Volatile alkali.
  Water                   Water.
C Hydruret of Sulphur, or")
?  fulphuret of  hydrogen  / Hitherto un-
C Hydruretofpbolphorusor T   known. *
]  phofphuret of hydrogen J
{ Hydro-carbonous, or car- jf Not known till
(_  bona-hydrous radicals f J   lately.
J Metallic  hydrurets J,  as 1 Hitherto  un-
    hydruret of iron, &c. j   known.
i
   * Thefe combinations take place in the ftate of gas, and
form, refpeftively, fulphurated and phofphorated hydrogen
gas.—A.
   + This combination of hydrogen with carbon includes the
fixed and volatile oils, and forms the radicals of a confider-
able  part of the vegetable and  animal oxyds  and acids.
When it takes place in the ftate  of gas, it forms carbonated
hydrogen gas.—A.
   + None of thefe  combinations are known, and it is pro-
bable that they cannot exift, at leaft in the ufual temperature
of the atmofphere, owing to the great aifinitv of hydrogen
for caloric.—A. 
OF  CHEMISTRY.
269
Sect. VII.—Obfervatinns upon Hydrogen, and its
      Combinations with Simple Subftances.

  Hydrogen, as its name expreffes, is one of the
conftituent elements of water, of which it forms
fifteen-hundredth  parts  by  weight, combined
with eighty-five  hundredth-parts of  oxygen.
This fubftance, the properties  and even  exift-
ence of which was unknown till lately, is very
plentifully diftributed in nature, and acts a very
confiderable part  in the proceffes of the animal
and vegetable kingdoms.  As it poffeffes fo great
affinity with caloric as only to  exift in the ftate
of gas, it is confequently impoflible to procure
it in the concrete or  liquid ftate, independent
of combination.
   To procure hydrogen, or  rather hydrogen
gas, we have only to fubjecl: water to the  action
 of a fubftance with which oxygen has a greater
 affinity than it has  to hydrogen ;  by this  means
the hydrogen is fet free, and,  by uniting with
 caloric, affumes the form of hydrogen gas.  Red
 hot iron is ufually employed for this purpofe :
 The  iron,  during the procefs, becomes oxyd-
 ated, and is  changed into a fubftance  refem-
 bling the iron ore from the ifland of Elba.  In
 this ftate of oxvd it is much lefs attractible by 
2/C>
ELEMENTS
the magnet, and diffolves in acids without effer-
vefcence.
   Charcoal, in a red heat, has the fame power
of decompofing water, by attracting the oxygen
from its combination with hydrogen.   In this
procefs carbonic acid gas is formed,  and mixes
with the hydrogen gas, but is eafily feparated
by means of water or alkalies, which abforb the
carbonic acid, and leave the hydrogen gas pure.
We may likewife obtain hydrogen gas by  dif-
folving iron or  zinc  in  dilute fulphuric acid.
The two metals decompofe  water very flowly,
and with great difficulty,  when alone,  but do it
with great eafe and rapidity when affifted by ful-
phuric acid ;  the hydrogen unites with  caloric
during the  procefs, and is difengaged in form
of hydrogen gas, while the oxygen of the wa-
ter unites with the metal in the form  of oxyd,
which is immediately diffolved in the acid, form-
ing a fulphat of iron or of  zinc.
   Some very diftinguifhed chemifts confider hy-
drogen as the phlogifton of Stahl;  and  as that
celebrated  chemift admitted the exiftence of
phlogifton in fulphur, charcoal, metals, kc. they
are of  courfe obliged to fuppofe that  hydrogen
exifts in all thefe fubftances,  though they can-
not prove their fuppofition ; even if they could,
it would not avail  much, fince this difengage-
ment of hydrogen is quite infufficient to explain
the phenomena of calcination and combuftion,. 
OF  CHEMISTRY.
27 j
We muft always recur to the examination of this
queftion, " Are the heat and light, which are
difengaged during the different fpecies of  com-
buftion,  furniflied by the burning body, or  by
the oxygen which combines in all thefe opera-
tions ?"  And certainly the fuppofition of hydro-
gen being difengaged throws no light whatever
upon this queftion.  Befides, it belongs to  thofe
who make  fuppofitions, to  prove them;  and,
doubtlefs, a doctrine which without any fuppofi-
tion explains the phenomena as well, and as na-
turally, as theirs does by fuppofition, has at leaft
the advantage of greater fimplicity *.
  * Thofe who wifh to fee what has been faid upon this
great chemical queftion by Meff. de Morveau, Berthollet, De
Fourcroy, and  myfelf, may confult  our tranflation of Mr.
Kirwan's Effay on Phlogifton.—A. 
272
ELEMENTS
  Simple
Subftances.
Caloric

Oxygen
Soft fulphur.
Sulphureous acid.
Vitriolic acid.
Table ofthe Binary Combinations of Sulphur with
                  Simple Subftances.
                            Refulting Compounds.
               New Nomenclature.      . Old Nomenclature.
              Sulphuric gas
            f Oxyd of  fulphur
            ■J Sulphurous acid
            (_ Sulphuric acid
              Sulphuret of hydregen
                           azot        .
                           phofphorus {
                           ■carbon
                            antimony
                            filver
                            arfenic
                            bifmuth
                            cobalt
                            copper
                            tin
                            iron
                            manganefe
Hydrogen
Azot
Phofphorus
Carbon
Antimony
Silver
^rfenio
Bifmuth
Cobalt
Copper
Tin
Iron
Manganefe

Mercury

 Molybdena
 Nickel
 Gold
 Platina
 Lead
 Tungftein
 Zinc

 Potafh
Soda


Ammoniac


Lime

Magnefia

Barytes

Argill


Unknown Combi-
  nations.

 Crude antimony.

 Orpiment realgar.


 Copper pyrites.

 Iron pyrites.
mercury
molybdena
nickel
gold
  f>latina
  ead
tungftein
 zinc

  potafh
foda
ammoniac
lime

 magnefia

 barytes
 arcrill
("Ethiops mineral,
J_   cinnabar.
  Galena.

  Blende.
r Alkaline liver of
■)  fulphur with fix-
{_  ed veget. alkali.
  Alkaline liver of
   fulpburwith fix-
   ed mineralalkali.
TVolatile liver of
\  fulphur, fmoak-
 j  ing  liquor of
/  Boyle.
  Calcareous  liver
   of fulphur.
  Magnefian liver of
   fulphur.
 CBarytic liver of
 £ fulphur.
  Yet unknown.
{ 
OF  CHEMISTRY.
273
Sect.  VIII.—Obfervations  on  Sulphur and its
                Combinations.

  Sulphur is a combuftible fubftance,  having a
very great tendency to combination ;  it is natu-
rally in a folid ftate in the ordinary  tempera-
ture, and  requires a heat fomewhat higher than
that of boiling water to make  it liquefy.  Sul-
phur is formed by nature in a  confiderable  de-
gree of purity in the neighbourhood of volca-
110s ; we find it, likewife, chiefly in the ftate of
fulphuric acid, combined with argill  in  alumi-
nous fchiftus, with lime in gypfum, &c.   From
thefe combinations it may be  procured  in  the
ftate of fulphur, by carrying off its oxygen by
means  of charcoal in a red  heat; carbonic acid
is formed, and efcapes in the  ftate of  gas;  the
fulphur remains combined with the clay, lime,
&c. in the ftate of fulphuret,  which is decom-
pofed by acids ;  the acid unites with  the earth
into a  neutral fait, and the fulphur is precipi-
tated.
Mm 
274
ELEMENTS
Table of the Binary Combinations of Phofphorus
           with the Simple Subftances.
     Simple Subftances.
Caloric

Oxygen

Hydrogen
Azot
Sulphur
Carbon
Metallic Subftances
Potafh
Soda
Ammoniac
Lime
Barytes
Magnefia
Argill
      Refulting Compounds.
  Phofphoric gas.
f Oxyd of phofphorus.
< Phofphorous acid.
C Phofphoric acid.
  Phofphuretof hydrogen.
  Phofphuret of  azot.
  Phofphuret of Sulphur.
  Phofphuret of carbon.
  Phofphurets of metals.*
■ Phofphuret  of Potafh,
    Soda, &c. f
  * Of all thefe combinations of phofphorus with metals,
tbat with iron only is hitherto  known, forming the fub-
ftance formerly  called Siderite ;  neither  is it yet  afcer-
tained whether, in this combination,  the  phofphorus be
oxygenated or not.—A.
  f Thefe combinations  of phofphorus with  the alkalies
and earths are not yet known; and, from the experiments
of Mr Gengembre, they appear to be impoflible.—A. 
OF  CHEMISTRY.
27$
Sect. IX.—Obfervations on  Phofphorus, and its
                Combinations.

  Phofphorus is a fimple combuftible fubftance,
which was unknown to chemifts till 1667, when
it was difcovered by Brandt, who kept the pro-
cefs fecret; foon after Kunkel found out Brandt's
method of preparation,  and made it public.  It
has been ever fince known by the name of Kun-
kePs phofphorus.  It was for  a long time pro-
cured only from urine ; and, though Homberg
gave an account of the  procefs in the Memoirs
of the academy for 1692, all  the philofophers
of Europe were fupplied with it from  England.
It was firft made in France  in 1737,  before  a
committee of the academy at the Royal Garden.
At prefent it is procured in a more commodious
and more economical manner from animal bones,
which are real calcareous phofphats, according
to the proceffes of Meffrs Gahn, Scheele, Rou-
elle,  &c.  The bones  of adult animals, being
calcined to whitenefs, are pounded, and paffed
through  a fine  filk fieve;  upon the  fine pow-
der a quantity of dilute 'fulphuric acid is pour-
ed, lefs than is fufficient  for diffolving the whole.
This acid unites with the calcareous earth of the
bones into a fulphat of lime,  and the phofpho-
ric acid remains free in the liquor.  The liquid 
B76        ELEMENTS

is decanted off, and the refiduum wrafhed wit-4
boiling v. at.*r ;  this water which has been ufed
to wafh out the adhering acid, is joined  with
what was before decanted off, and the whole  is
gradually  evaporated ;  the diffolved  fulphat  of
lime cryftallizes in form of filky threads, which
are removed ;  and, by continuing the evapora-
tion, we procure the phofphoric acid, under the
appearance of a white pellucid glafs.  When this
is powdered, and mixed with one third its weight
of  charcoal,  we procure very pure phofphorus,
by  fublimation *.   The phofphoric acid, as pro-
cured by the above procefs, is never fo pure as
that obtained by  oxygenating pure phofphorus,
either by combuftion or by means of nitric acid ;
wherefore this latter fhould ahvays be employed
in experiments of refearch.
   Phofphorus is found  in almoft all animal fub-
ftances, and in fome plants which give a  kind

  * A very convenient method of procuring phofphorus
from urine has lately been difcovered.   The phofphoric acid
is precipitated by a folution of acetite of lead, by means of
a double decompofition : the lead uniting with the phofpho-
ric acid into an infoluble fait which precipitates, while  the
acetous acid unites with the alkaline fubftances of the urine
and remains diffolved.  The phofphat of lead is then repeated-
ly wafhed, and is decompofed by means of muriatic acid : a
• muriat of lead is formed, which is infoluble, and the phof-
phoric acid is found in a liquid ftate ; this is evaporated to
drynefs, and, being difoxygenated by charcoal, in the ufaal
fanner, a very pure phofphorus fublimes.—T. 
,  OF  CHEMISTRY.
277
  of  animal analyfis.   In all  thefe  it is ufually
  combined  with carbon, hydrogen,  and azot,
  forming very compound radicals, which are, for
  the mod part,  in  the  ftate of oxyds, by a  firft
  degree of union with  oxygen.   The difcovery
  of Mr  Haffenfratz, of  phofphorus  being con-
  tained in charcoal, gives reafon to  fufpedt  that
  it is more common in the vegetable kingdom
  than has generally been fuppofed. It is certain,
  that by proper proceffes, it  may be procured
  from every individual of fome  of  the  families
  of plants.   As no experiment has hitherto giv-
  en reafon to  fufpedt that phofphorus is  a com-
  pound body, I have arranged it  with the fimple
  or elementary fubftances.   It takes  fire at the
  temperature  of 104° of the thermometer.

   Table of the Binary Combinations of Carbon.
   Simple                 Refulting Compounds.
 Subftances.      New Nomenclature.         Old  harr.es.
 -.         f Oxyd of carbon        Unknown.
   '°      ^C.rbonic acid          Fixedair,chalkyacid.
 Sulphur     Carburet of fulphur    "7
 Phofphorus  Carburet of phofphorus > Unknown.
 Azot       Carburet of azot      J
 u  ,         f Carbono-hydrous radicals
  y   to      \ Fixed with volatile oils
                                   f Of thefe only die
                                   I  carburetsofiron
..Metallic  fub-1 Carburets of  the feveral !   ,    '    ".
    n        >       ,               <   known,  ana
   itances.   1   metals.                      f  ,^,m.\„
            J                         were formerly
                                      called Plumba-
l  g°-
Earth's 8nd} Carburet of potafli, &c    Unknown. 
2^8
ELEMENTS
Sect.X.—Obfervations upon Carbon, and its Com-
        binations with Simple Subftances.

  As carbon has  not been  hitherto decompof-
ed, it muft, in the prefent  ftate of  our know-
ledge, be confidered as a fimple fubftance.  By
modern experiments  it appears  to  exift ready
formed in vegetables ; and I have  already re-
marked, that, in  thefe, it is combined with hy-
drogen, fometimes with azot and phofphorus,
forming  compound radicals,  which  may be
changed into oxyds or acids, according to their
degrees of oxygenation.
   To obtain the  carbon *  contained in vegeta-
table or animal fubftances, we fubject them to the
action of fire, at  firft moderate,  and afterwards
very ftrong, on purpofe to drive off  the laft por-
tions of water, which adhere very  obftinately.
For chemical  purpofes this is ufually  done  in
retorts of ftone-ware or porcelain, into which the
wood,  or other matter, is introduced, and then
placed in a reverberatory furnace, raifed gra-
dually to its greateft  heat:  The heat volatilizes,

   * It is neceflary to repeat, that carbon is ufed to denote
tlie pore fimple elementary fubftance, while charcoal fignifies
that fubftance, united with fome fmall portions of earths and
falts,  as procured from vegetable and animal bodies, by burn-
ing ox 'ay diftUtauan in a red heat.—T. 
        OF   CHEMISTRY.     279

or changes into gas, all the parts of the body
fufceptible of combining with caloric into that
form ; and the carbon being more fixed in  its
nature, remains in the retort, combined with a
little earth and fome fixed falts, in the form ge-
nerally known by the name of charcoal.
  In the bufinefs of charring wood, this  is done
by  a lefs expenfive procefs.  The wood is dif-
pofed in heaps regularly arranged, and covered
with earth, fo as to prevent the accefs of any
more air than  is abfolutely neceffary for fupport-
ing  the  fire,  which  is kept up till all the wa-
ter and oil is driven off, after which the fire  is
extinguifhed by fhutting up all the air-holes.
  We may  analyfe charcoal either by combufti-
on in air, or rather in oxygen gas, or by means
of nitric acid :  In either cafe we convert its pure
carbon into  carbonic acid ;  and  fometimes a lit-
tle potafh and  fome neutral falts  remain.  This
analyfis has been hitherto but little attended to
by chemifts; and we are not even certain if pot-
afli  exifts in  charcoal before  combuftion,  or
whether it  be  formed  by means of fome un-
known combination during that procefs.

Sect. XI.—Obfervations upon the Muriatic, Flu-
  oric, and  Boracic Radicals, and their Combina-
  tions.

  As the combinations of thefe fubftances,  ei-
ther with each other, or with the other combuf- 
280
ELEMENTS
tible bodies, are hitherto entirely unknown, we
have not attempted to form any table for  their
nomenclature.  We only know, that thefe radi-
cals are fufceptible of oxygenation, and of form-
ing the muriatic, fluoric, and boracic acids: and
that,  in the acid ftate, they enter into a number
of combinations, to be afterwards detailed. Che-
miftry has hitherto been unable to  difoxygenate
any of thern,  fo as to exhibit them in a fimple
ftate.  For this purpofe, fome fubftance muft
be employed,  to  which oxygen has a ftronger
affinity than to their radicals,  either by means
of fingle affinity,  or  by double elective attrac-
tion.  All that is known relative to the origin
of the radicals of thefe acids, will be mentioned
in  the fedtions fet apart for  confidering their
combinations  with the falifiable bafes.


Sect. XII.—Obfervations  upon the Combinations
           of Metals with each other.

   Before clofing  our account of  the fimple  or
elementary fubftances,  it might be fuppofed ne-
ceffary to give a table of alloys or combinations
of metals with each other; but,  as fuch a  ta-
ble would be both exceedingly voluminous and
 very unfatisfadtory, without going into a feries
 of  experiments  not  yet attempted,   I have
 thought it advifeable to omit it altogether.  All 
         OF CHEMISTRY       28*

that is neceffary to be mentioned, is,  that thefe
alloys  fhould be named  according to the metal
in largeft  proportion in  the mixture or combi-
nation  j  thus the  term alloy of gold  and filver,
or gold alloyed  with filver,  indicates that gold
is the predominating metal.
  Metallic alloys, like all other combinations,
have a point of faturation.   It  would even ap-
pear, from the experiments by Mr de la Briche*
that they have two perfectly diftinct degrees of
faturation;
Nn
Tabl$ 
282
ELEMENTS
Table of  the Combinations of Azot, in the ftate of
   Nitrous Acid, with the Salifiable Bafes, arranged
   according to the Affinities of  thefe Bafes with the
   Acid.
Name's ofthe
     Bafes.
Barytes
Potafh
Soda
Lime
Magnefia
Ammoniac
Argill
Names of the Neutral Salts.
 New Nomenclature.
Nitrite of barytes.    f
          potafh.
          foda.
          lime.
          magnefia.
          ammoniac.
          argill.
Oxyd of zinc
        iron
        manganefe
        cobalt
        nickel
        lead
        tin
        copper
        bifmuth
        antimony
        arfenic
        mercury
filver
gold
platina
        Notes.

 Thefe falts are on-
ly known of late, and
have received no par-
ticular names in the
old nomenclature.
                    ~  As metals diffolve
                     both in nitrous and
                     nitric acids, metallic
         zinc.        falts  muft of confe-
         iron.        quence be formed ha-
         manganefe.   ving  different  de-
         cobalt,       greesofoxygenation.
         nickel.       Thofe  wherein  the
         lead.      -^ metal is leaft oxygen<
         tin.         ated, muft be called
         copper.      Nitrites, and  when
         bifmuth.     more fo, Nitrats; but
         antimony,   the limits of this dif-
         arfenic.      tinftion are difficult-
         mercury,    ly afcertainable. The
                     older chemifts were
                     not acquainted  with
                    _any of thefe falts.
f  It is extremely probable that gold, filver
< and platina, only form nitrats, and cannot
£ fubfift in the ftate of nitrites.
Table 
OFCHEMISTRY.
283
 Table ofthe Combinations of Azot, completely fatu-
   rated with Oxygen,  in  the Jlate of Nitric acid,
   with the Salifiable Bafes, in the Order of their Af-
   finity with that Acid.
                Names of the refulting Neutral Salts.
Bafes.
Barytes   Nitrat of barytes
Potafh


Soda

Strontites


Lime


Magnefia

Ammoniac

Argill


°xyd of zinc

     iron

     manganefe
     cobalt
     nickel

     lead

     tin

     copper

     bifmuth
     antimony
     arfenic
     mercury

     filver
     gold
     platina
potafh

foda

ftrontites
New iSomenclature.    Old Nomenclature.
                | Nitre,  with  a bafe of
                \   heavy earth.
                j Nitre,  faltpetre, Nitre
                \   with bafe of potafh.
                f Quadrangular    Nitre,
                <   rtttre  with bafe of
                t   mineral alkali.
                  Unknown.
                f Calcareous nitre.  Ni-
                )  tre   with  calcareous
                j  bafe, Mother water of
                £  nitre, or of faltpetre.
                C Magnefian nitre, Nitre
                \ with bafe of magnefia.
                  Ammoniacal nitre.
                  Nitrous  alum,  Argil-
                   laceous  nitre,   Nitre
                   with bafe of earth of
                   alum.
                  Nitre of zinc.
                J Nitre of iron, Martial
                \  nitre,  Nitrated iron.
                  Nitre of manganefe.
                 Nitre of cobalt.
                 Nitre of nickel.
                C Saturnine nitre,  Nitre
                \ of lead.
                  Nitre of tin.
                C Nitre of copper, or of
                \  Venus.
                  Nitre of bifmuth.
                  Nitre of antimony.
                  Arfenical nitre.
                  Mercurial Nitre.
                f Nitre of filver,  or of
                I  luna, Lunar cauftic.
                  Nitre of gold.
                  Nitre of platina.
lime


magnefia

ammoniac


argill


zinc

iron

manganefe
cobalt
nickel

lead

tin

copper

bifmuth
antimony
arfenic
mercury

filver

gold
platina
[ 
 284          ELEMENTS


 Sect.  XIII.—Obfervations upon  the  Nitrous and
        Nitric Acids, and their Combinations.

    The nitrous  and nitric acids are procured
 from a neutral fait, long known in the arts, un-
 der  the name otfaltpetre.   This fait is extracted
 by lixiviation from the rubbifh of old buildings,
 from the  earth of cellars, ftables, or barns,  and
 in general  of all  inhabited places*.  In thefe
 earths, the nitric acid  is ufually combined with
 lime and magnefia, fometimes with potafh,  and
 rarely with argill.   As all thefe  falts, excepting
 the nitrat of potafh, attract the moifture of the
 air,  and confequently would be difficultly pre-
 ferved, advantage is taken,  in the manufactories
 of faltpetre, and in the royal refining houfe, of
 the greater  affinity  of  the nitric acid to  potafh
 than thefe other bafes; by which means  the lime,
 magnefia,  and argill,  are precipitated,  and all
 thefe nitrats are reduced to the nitrat of potafh,
 or faltpetre.
   The nitric acid is procured from this  fait by
 means of diftillation.  Three parts ofpurefalt-


  • Saltpetre is likewife procured in large quantities by
lixiviating the  natural foil in fome parts of Bengal, and of
the Ruffian Ukrain.—T. 
         OF  CHEMISTRY.        285

 petre are decompofed by means of one  part of
 concentrated fulphuric acid,  in  a retort with
 Woulfes' apparatus,  (PI. IV. Fig. 1.)  having
 its  bottles  half  filled with water, and  all its
 joints  carefully luted.   The nitrous acid  paffes
 over in form of red  vapours furcharged with  ni-
 trous gas,  or, in other words, not completely
 faturated with oxygen.   Part of the acid  con-
 denfes in the recipient, in  form of a  dark o-
 range red liquid; while the reft combines  with
 the water in  the bottles.    During the  diftilla-
 tion,  a large  quantity of  oxygen  gas efcapes,
 owing to the greater  affinity of oxygen to calo-
 ric, in a high  temperature, than to  nitrous acid j
 though  in the ufual  temperature of the atmof-
 phere,  this  affinity is  reverfed.  It is from the
 difengagement of oxygen,  that the  nitric acid
 ofthe neutral fait is in  this operation converted
 into nitrous acid*.   It  is  brought  back  to the
 ftate of nitric acid by heating over a gentle fire,
 which  drives  off the fuperabundant nitrous gas,
 and leaves  the nitric acid  much  diluted  with
 water.


  * It is evident, that  in this operation,  there is  a very
great lofs of nitric acid;  as,  from the difengagement of
oxygen, we cannot poffibly procure near the fame quantity
of nitric acid by diftillation, thatexifted in the combined ftate
in the nitre.—T. 
aS6         ELEMENTS

  Nitric acid is  procurable  in a more concen-
trated ftate, and with much lefs lofs,  by  mixing
very dry  clay  with faltpetre.    This  mixture
is  put  into  an earthen retort, and diftilled with
a ftrong fire.   The clay combines with the pot-
afh,  for which it has great affinity j  and the ni-
tric acid paffes over, flightly impregnated with
nitrous  gas.  This is eafily difengaged by heat-
ing the  acid gently in a retort; a fmall  quantity
of nitrous gas paffes over into the recipient •, and
very pure concentrated nitric acid remains in the
retort.
   We have already feen, that azot  is the nitric
radical.   If to io\; parts by weight, of azot,
434- parts of oxygen be  added,  64 parts  of  ni-
trous gas are formed ■, and if to this we join 36
additional parts of oxygen,  100 parts of nitric
acid refult from the combination.  Intermediate
quantities of oxygen,  between  thefe  two ex-
tremes  of oxygenation, produce different fpe-
cies of nitrous acid •, or, in other words,  nitric
acid lefs or more impregnated  with nitrous gas.
I afcertained the  above  proportions by means of
decompofition; and though I cannot  anfwer for
their abfolute accuracy,  they cannot be far  re-
moved from truth.   Mr Cavendifh,  who firft
mewed  by  fynthetic experiments, that azot is
the bafe of  nitric acid, gives the proportions of
azot a little larger than I have done : but, as it
is not improbable, that he produced the nitrous 
       O F  C H E M I S T R Y.       **?

acid,  and not the nitric, that circumftance*«-
plains in  fome  degree  the difference in the re^
fults of our experiments.
  As, in  all  experiments of a philofophical na«
ture,  the  utmoft poffible degree of accuracy is
required,  we muft procure the nitric acid for
experimental  purpofes, from nitre which has
been  previoufly  purified from all  foreign  mat-
ters.   If,  after  diftillation, any fulphuric acid is
fufpeCted  in the nitric acid,  it is eafily fcparated
by dropping in a little nitrat  of barytes, fo long
as any  precipitation takes place; the fulphuric
acid, from  its greater affinity,  attracts the bary-
tes, and forms with it an infoluble neutral fait,
which falls to the  bottom.  It may be purified
in* the  fame  manner  from muriatic acid,  by
dropping  in  a  little nitrat of filver,  fo long as
any precipitation of muriat of filver is produced.
When thefe two precipitations are finifhed, dif-
til off about feven-eighths ofthe acid by a gentle
heat, and what comes over is in the moft perfect
degree of purity.
  The  nitric acid is remarkably prone to com-
bination, and  is at the  fame time  very eafily
dccompofed.   Almoft all the fimple fubftances,
with the exception of gold, filver, and platina,
rob it lefs or  more  of oxygen;  fome of them
even decompofe it  altogether.  Ic  was very an-
ciently  known :  and its  combinations have been
more  ftudied by chemifts  than thofe of any o- 
ttt         ELEMENTS

ther  acid.   Thefe  combinations were  named
nitres by Meffrs Macquer and Beaume :  but we
have changed their names to  nitrats and nitrites,
according as they are formed by nitric or by ni-
trous acid; and have added the fpecific name of
each particular bafe, to diftinguifh the feveral
combinations from each other. 
OF   CHEMISTRY.
289
Table  of the Combinations of Sulphuric Acid with
  the  Salifiable  Bafes,  in  the Order of Affinity.
Names of the Bafes.
      New Nomenclature.
Barytes	Sulphat of barytes
Strontites	ftrontites
Potafh	potafh
Soda	foda
iL-ime	lime
Magnefia	magnefia
Ammoniac	ammoniac
Argill	argill
Oxyd of zinc	zinc
iron

manganefe
cobalt
nickel
lead
tin

copper

bifmuth
 iron

manganefe
cobalt
nickel
 lead
tin

copper

bifmuth
antimony	antimony
arfenic	arfenic
mercury	mercury
filver	fdver
gold	gold
piatina	platina
	O 0
  Refulting Compounds.
  Old Nomenclature.
  f Heavy fpar,  Vitriol
  \   of heavy earth.
    Unknown.
  f Vitriolated tartar, Sal
 ■1   de duobus, Arcanum
  £   duplicatum.
    Glauber's fait.
 J Selenite, gypfum, cal-
 \   careous vitriol.
 | Epfomfalt,Sedlitzfalt,
 \   Magnefian vitriol.
 t  Glauber's fecret  fal
 \   ammoniac.
    Alum.
 f White vitriol, Goflar
■^  vitriol, White cope-
 £ ras, Vitriol of zinc.
 f Green copperas,Green
<  vitriol, Martial vitri-
 fy Ol, Vitriol of iron.
   Vitriol of manganefe.
   Vitriol of cobalt.
   Vitriol of nickel.
    Vitriol  of lead.
   Vitiiolof tin.
 ( Bluecopperas, Blue vi-
<  triol, Roman vitriol,
£ Vitriol of copper.
   Vitriol of bifmuth.
   Vitriol of antimony.
   Vitriol of arfenic.
   Vitriol of mercury.
   Vitriol of filver.
   Vitriol of gold.
   Vitriol of platina. 
290
ELEMENTS
Sect.  XIV.—Obfervations upon  Sulphuric Acid,
             and its Combinations.

  For a  long time, this acid was procured  by
diftillation  from fulphat of iron,  in which ful-
phuric acid and oxyd  of iron  are combined,
according to the procefs defcribed by Bafil Va-
lentine in  the  fifteenth century;  but, in mo-
dern times, it is procured more  economically
by the combuftion  of fulphur in  proper veffels.
Both  to  facilitate  the combuftion, and to affift
the oxygenation of the fulphur, a  little  powder-
ed faltpetre, or nitrat of potafh,  is mixed with
it j  the nitre is decompofed, giving out  its oxy-
gen to the  fulphur,  and contributes to  its con -
verfion into an  acid.  Notwithstanding  this ad-
dition, the  fulphur will only continue  to burn,
in clofe veffels, for a limited time j the combina-
tion foon ceafes, becaufe the oxygen is  exhauft-
ed, and the air ofthe veffels is  reduced almoft to
pure azotic gas; and becaufe the acid itfelf  re-
mains  long in the ftate  of vapour, and hinders
the progrefs of combuftion.
  In  the  manufactories  for  making  fulphuric
acid in the large way,  the mixture of nitre and
fulphur is  burnt in large  clofe-built chambers,
lined with lead,  having  a little water at  the bot-
tom, for facilitating the condcnfation of the  va-
pours.  Afterwards, by diftillation in large  re- 
OF  CHEMISTRY.
291
torts with a gentle  heat, the water paffes over,
flightly impregnated  with acid,   and the ful-
phuric acid remains  behind in a  concentrated
ftate.   It is then pellucid,  without  any flavour,
and nearly double the weight of an equal bulk
of water.   This procefs would be greatly faci-
litated,  and the combuftion much prolonged,
by introducing frefh  air into the chambers, by
means of feveral pairs of bellows, directed towards
the flame ofthe fulphur, and by allowing the ni-
trous gas to efcape through long ferpentine canals,
in contact with  water, to abforb any fulphuric or
fulphurous acid gas it might contain.
  By one experiment,  Mr Berthollet  found that
69 parts of fulphur in combuftion, united  with
31 parts of oxygen,  to form  100  parts of ful-
phuric acid :  and, by another experiment, made
in a different  manner,  he calculates  that 100
parts of fulphuric acid confift of 72 parts of ful-
phur, combined with  28 parts of oxygen, all by
weight.
  This acid, in common  with every other, can
only diffolve  metals  when  they have  been pre-
vioufly oxydated:  but  moft of the  metals are
capable of  decompofing a  part of the acid,  fo
as to carry  off a fufficient quantity of oxygen,
to render themfelves foluble in the part of the
acid which remains undecompofed.   This hap-
pens with filver, mercury, iron,  and zinc,  in
boiling concentrated  fulphuric acid •,  they  be-, 
292
ELEMENTS
come firft oxydated  by  decompofing part of
the  acid, and are then  diffolved  in  the  other
part.  But they do not fufficiently difoxygenate
the decompofed part of the acid, to reconvert  it
into fulphur.  It is only  reduced to the ftate of
fulphurous acid, which,  being volatilifed by the
heat, flies off in the form  of fulphurous acid gas.
   Silver, mercury, and all the other metals, ex-
cept iron and zinc,  are infoluble in  diluted ful-
phuric  acid, becaufe  they have  not fufficient
affinity with oxygen to withdraw it from its com-
bination  either  with the  fulphur, the fulphu-
rous acid, or the hydrogen;  but iron and zinc,
being aflifted by the action of the acid, decom-
pofe the water, and become oxydated at  its ex-
pence,  without  the help  of heat. 
OF  CHEMISTRY.
*93
Table of the Combinations of the Sulphurous A-
   cid with  the  Salifiable  Bafes, in  the Order of
   Affinity.
Names ofthe Bafes.	Names of the Neutral Salts.
Barytes	Sulphite of barytes.
Potafh	potafh.
Soda	foda.
Lime	lime.
Magnefia	magnefia.
Ammoniac	ammoniac.
Argill	argill.
Oxyd of zinc	zinc.
iron	iron.
manganefe	manganefe.
cobalt	cobalt.
nickel	nickel.
lead	lead.
tin	tin.
copper	copper.
bifmuth	bifmuth.
antimony	antimony.
arfenic	arfenic.
mercury	mercury.
filver	filver.
gold	gold.
platina	platina.
   Note.-----The  only  one of thefe falts known  to the  old
 chemifts was the fulphite of potafh,  under the name of Stahl*s
fulphureous fait: So that, before our new nomenclature, thefe
 compounds muft have been named Stahl's fulphureous fait,  ha-
 ving bafe of fixed vegetable alkali; and fo ofthe reft.
   In this Table we have followed Bergman's  order of affini-
 ty of the  fulphuric acid, which is the fame in regard to  the
 earths and alkalies ;  but it is not certain if the order be  the
"fame for the metallic oxyds.—A. 
294
ELEMENTS
Sect.  XV.—Obfervations upon  Sulphurous Acid,
             and its Combinations.

   The  fulphurous acid  is formed by the union
of oxygen with fulphur,  in  a leffer degree of
oxygenation than the fulphuric  acid.  It  is pro-
curable either  by  burning fulphur flowly, or by
diftilling  fulphuric acid from filver, antimony,
lead, mercury, or charcoal.   By thefe operations
a  part  of the  oxygen quits the acid, uniting to
thefe  oxydable  bafes •, and the acid paffes over
in the  fulphurous ftate of oxygenation.   This
acid,  in the common preffure and temperature
of the air, can only exift in form of gas.   But it
appears, from the experiments of Mr Clouet,
that,  in a very low  temperature, it condenfes,
and becomes fluid.  Water abforbs a great deal
more  of this gas than of  carbonic acid gas, but
much lefs than  it does of muriatic acid gas.
   That the metals cannot be  diffolved in acids
without being  previoufly oxydated, or by pro-
curing oxygen,  for that purpofe, from the acids
during  folution, is a general and well eftablifhed
fact:,  which  I have perhaps repeated too often.
Hence, as fulphurous acid is  already deprived of
great  part  of  the oxygen neceffary for forming
the fulphuric acid, it  is  more difpofed to reco-
ver oxygen, than to  furnifh  it to the greatcft
part of the metals j  and, for this reafon, it can- 
OF CHEMISTRY.
295
not diffolve them, unlefs  previoufly oxydated
by other means.   From the fame  principle it is,
that the metallic  oxyds diffolve  without  effer-
vefcence, and with great facility, in fulphurous
acid.  This acid, like the muriatic, has even the
property of diffolving metallic oxyds furcharg-
ed with oxygen,  and which  are, confequently,
infoluble in fulphuric acid :  and in this way true
fulphats are formed.  Hence  we might be  led
to conclude, that there are no metallic fulphites,
were it not  that the phenomena which  accom-
pany the folution  of  iron, mercury,  and fome
other metals,  convince us, that  thefe  metallic
fubftances are fufceptible of two degrees  of oxy-
dation, during their  folution  in  acids.  There-
fore the neutral fait, in which  the metal is leaft
oxydated, muft be named fulphite ; and that in
which it is fully oxydated, muft be called fulphat.
It is yet unknown whether this  distinction is  ap-
plicable to any of the  metallic fulphats, except
thofe of iron or mercury. 
296
ELEMENTS
Table  of the  Combinations  of  the Phofphorous
   and Phofphoric Acids,  with the Salifiable  Bafes
   in the Order of Affinity.
Names ofthe            Names ofthe Neutral Salts formed by
    Bafes.             Phofphorous Acid.   Phofphoric Acid.

Lime

Strontites
Barytes
Magnefia
Potafh
Soda
Ammoniac
Argill
Oxyds of*
  zinc
  iron
  manganefe
  cobalt
  nickel
  lead
  tin
  copper
  bifmuth
  antimony
  arfenic
  mercury
  filver
  gold
  platina

  * The exiftence of metallic  phofphites fuppofes that me-
tals are fufceptible of folution in phofphoric acid at different
degrees of oxygenation, which  is not yet afcertained.—A.
  f All the phofphites  were  unknown till  lately; and confe-
quently have not hitherto received  names.—A.
  % The  greater  >art of the phofohats were  only difcovered
of late;  and have not yet been  named.—A.
Phofphites of f lime	Phofphats of \ lime.
ftrontites	ftrontites.
barytes magnefia potafh foda	barytes. magnefia. potafh. foda.
ammoniac	ammoniac.
argill	argill.
zinc	zinc.
iron	iron
manganefe cobalt	manganefe. cobalt.
nickel	nickel
lead	lead.
tin	tin.
copper bifmuth	copper. bifmuth.
antimony arfenic	antimony. arfenic.
mercury	mercury.
filver	filver.
gold platina	gold. platina.
 
OF  CHEMISTRY.
297
Sect.  XVI.—Obfervations upon Phofphorous and
    Phofphoric Acids, and their Combinations.

  Under the  article Phofphorus,  Part II. Sect:.
IX.  we have already given a hiftory ofthe dif-
covery of that fingular fubftance, with fome ob-
fervations upon the mode of its exiftence in ve-
getable and animal bodies.   The  beft method
of obtaining this acid in a ftate of purity is by
burning  well purified  phofphorus  under bell-
glaffes,  moiftened  on  the  infide with diftilled
water.   During combuftion it abforbs twice and
a half its weight  of oxygen ; fo that 100 parts
of phofphoric acid  is  compofed  of 28-i parts of
phofphorus united to 714- parts of oxygen. This
acid  may be obtained concrete, in form of white
flakes, which greedily attract: the moifture ofthe
air, by burning phofphorus in a dry glafs over
mercury.
  To  obtain phofphorous acid, which is phof-
phorus lefs oxygenated than in the ftate of phof-
phoric acid, the phofphorus muft be burnt by a
very flow fpontaneous combuftion over a glafs
funnel leading into a cryftal phial.  After a few
days, the phofphorus  is found oxygenated, and
the phofphorous acid, in proportion as it forms,
attracts moifture from the air,  and drops into the
phial.   The phofphorous acid is.readily changed
into  phofphoric acid by expofure for a long time
                        PP 
293
ELEMENTS
to the free air.   It abforbs oxygen from the air,
and becomes fully oxygenated.
   As phofphorus has a fufficient affinity for oxy-
gen  to attract: it from the nitric and oxygenated
muriatic acids,  we may  form phofphoric  acid,
by means of thefe  acids, in a very fimple  and
cheap manner.   Fill a tubulated receiver,  half
full of concentrated nitric acid, and heat it gently:
then throw in fmall pieces of phofphorus through
the tube. Thefe are diffolved with effervefcence j
and red fumes of nitrous gas fly off. Add phofpho-
rus fo long as it will diffolve : and then increafe
the  fire  under the  retort,  to drive off the laft
particles of nitric acid : phofphoric acid,  partly
fluid and partly concrete,  remains in the retort. 
OF  CHEMISTRY.
299
Barytes

Lime
Strontites

Potafh

Soda

Magnefia

Ammoniac

Argill
Oxyds of
  zinc
1
 Table ofthe Combinations of  Carbonic Acid, with
    the Salifiable  Bafes,  in the  Order of Affinity.

 Names ofthe Bafes.     Refulting Neutral Salts.
               New Nomenclature.      Old Nomenclature.
                             ( Aerated or Effervefcent  hea-
                             (   vy earth.
                             J Chalk, Calcareous fpar,
                             \   Aerated calcareous earth.
                               Unknown.
                               Effervefcing or Aerated fixed
                                 vegetable alkali. Mephitis
                                 of potafh.
                              f Aerated or Effervefcing fixed
                              I mineral alkali, Mephitic foda.
                              ("Aerated, effervefcing, mild,
                              I   or mephitic magnefia.
                              f Aerated, effervefcing, mild or
                             \   mephitic, volatile alkali.
                             ( Aerated or effervefcing argil-
                             l laceous earth.or earth of alum.
                             C Zinc fpar, Mephitic or aera-
                             \   ted zinc.
                             C Sparry iron-ore, Mephitic or
                             |   aerated  iron.
                               Aerated manganefe.
                               Aerated cobalt.
                               Aerated nickel.
                               Sparry lead ore,  or Aerated
                                 lead.
                               Aerated tin.
                               Aerated copper.
                               Aerated bifmuth.
                               Aerated antimony.
                               Aerated arfenic.
                               Aerated mercury.
                               Aerated filver.
                               Aerated gold.
                               Aerated platina.
   *  As thefe falts have only been underftood cf late,  they have
not properly fpeaking, any old n.*mes  Mr Morveau,  in the firft
Volume ofthe Encyclopedia, calls them Mephites ; Mr Bergman
gives them the name ofaerated j and Mr de Fourcroy, who calls
the carbonic acid chalky acid, gives them the name of chuiL—A.
Carbonats of*
  barytes
lime
ftrontites

 potafh

 foda

 magnefia

 ammoniac

 argill

 zinc

 iron
manganefe
cobalt
nickel
lead

tin
copper
bifmuth
antimony
arfenic
mercury
filver
gold
platina
manganefe
cobalt
nickel

lead

 tin
 copper
 bifmuth
 antimony
 arfenic
 mercury
 filver
 gold
 platina 
300
ELEMENTS
 Sect. XVII.—Obfervations  upon  Carbonic Acid,
              and its Combinations.

   Of all the known  acids, the carbonic  is the
 moft abundant in nature.   It exifts ready form-
 ed  in chalk, marble,  and  all the  calcareous
 (tones, in which it is neutralized by a  particu-
 lar earth, called  lime.   To difengage it from this
 combination, nothing  more is requifite, than to
 add fome  fulphuric acid, or  any other which
 has a ftronger affinity for lime.  A brifk effervef-
 cence enfues, which is  produced by the difenga-
 ged carbonic acid affuming the ftate of gas,  im-
 mediately upon being fet  free.  This gas, inca-
 pable of being condenfed into  the folid or liquid
 form  by any degree of cold or of preffure hither-
 to known, unites to about its own bulk of water,
 and thereby forms a very  weak acid liquor.  It
 may likewife  be obtained in  great abundance
 from  faccharine  matters in fermentation :  but is
 then contaminated by a frnail portion of alkohol,
 which it holds in folution.
  As carbon is the radical of this acid,  we may
 form  it artificially, by  burning charcoal in oxy-
 gen gas, or by combining charcoal  and metallic
 oxyds in  proper proportions. The oxygen ofthe
 oxyd  combines with the carbon, forming carbo-
nic acid gas: and the metal being left free, reco-
vers its metallic  or reguline form. 
       OF  CHEMISTRY.        3°*

   We are indebted  for  our firft  knowledge of
this acid to Dr Black, before whofe time its pro-
perty of remaining always  in the ftate of gas had
made it elude the refearches of chemiftry.
   It would be a  moft valuable difcovery to fo-
ciety,  if we  could decompofe this gas by any
cheap procefs ;  as  by that means we might ob-
tain,  for  economical purpofes,   the immenfe
ftore of charcoal contained in  calcareous earths,
marbles,  limeftones, &c.  This  cannot be ef-
fected by fingle affinity ;  becaufe,  to decompofe
the  carbonic acid,  it requires  a  fubftance  as
combuftible  as charcoal itfelf -,  fo that we fhould
only  make an exchange of one combuftible bo-
dy for another not more valuable.   But it  may
poffibly  be  accompliihed* by  double  affinity;
fince this procefs is fo readily performed by Na-
ture, during vegetation,  from the moft common
materials.
  * Mr Smithfon Tennant has given,  in the Phil. Tranf. for
1791, Art.  XI. fome experiments on the  decompofition of
carbonic acid.  Some powdered marble,  flightly calcined,
and fome phofphorus, being introduced into a glafs tuhe, coat-
ed with a lute of fand and clay, are kept in a red heat for
fome minutes, and fuffered to cool.  On breaking the tube, a
black powder is found, which confifts of charcoal and phof-
phat of lime.  In the laboratory of Dr Black,  the  decompo-
fition has been produced, via humida.  Some folution of  fill*
phuret of potafh  which had ftood for feveral days in an open
matrafs, expofed to the air of the room, which had been
breathed by feveral hundred ftudents, was  found to have de-
poficed charcoal on the fides ofthe veffel.—-T. 
JOS
ELEMENTS
Table  ofthe Combinations of Muriatic Acid  with

    the Salifiable Bafes,  in the Order of affinity.

Names ofthe
  Bafes.
Barytes
           Refulting Neutral Salts.
Ntw Nomenclature.       Old Nomenclature.
Muriat of
  barytes
bafe of
Potafh

Soda
Strontites
Lime
potafh

foda
ftrontites

lime
Magnefia  magnefia
Ammoniac ammoniac

Argill     argill
Oxyd of
  zinc
  iron
zinc
iron
manganefe manganefe
cobalt
nickel
lead
cobalt
nickel
lead
tin

Copper
bifmuth
antimony
arfenic
                  C Sea-falt  having
                 \   heavy earth.
                 i Febrifuge fait of Sylvius,
                < Muriated vegetable fixed
                 (   alkali.
                   Sea fait.
                  Unknown.
                 f Muriated lime.
                 \ Oil of lime.
                 C Marine Epfom fait.
                 \ Muriated magnefia.
                  Sal ammoniac.
                 f Muriated alum,  Sea-falt
                 <   with bafe of earth of
                 £   alum.
                  Sea-falt of zinc, or Mu-
                     riatic zinc.
                  Salt of  iron, or  Martial
                     fea-falt.
                  Sea-falt of manganefe.
                  Sea-falt of cobalt.
                  Sea-falt of nickel.
                 J Horny lead, or Plumbum
                 \   corneum.
fmoaking, of  tin CSmoaking liquor of  Li-
   folid, of tin
copper
bifmuth
antimony
arfenic
mercurv
filver
gold
platina
    fweet,  of mercury

    corrofive, of mer-
      cury

filver

gold
platina
■1   bavius.
£ Butter of tin.
  Sea-falt of copper.
  Sea-falt of bifmuth.
  Sea-falt of antimony.
  Sea-falt of arfenic.
  Sweet fublimate of mer-
    cury,  Calomel, Aquila
    alba.
  Corrofive  fublimate   of
\   mercury.
j Horny fiiver,  Argentum
\   corneum,  Luna cornea.
 Sea  fait of gold.
  Sea-falt of Platina.
{ 
OF  CHEMISTRY.
303
Table of the Combinations of Oxygenated Muria-tic Acid with the Salifiable Bafes, in the Order of Affinity. Names ofthe Neutral Salts ly Names ofthe Bafts. the New Nomenclature.	
	Oxygenated muriat of
Barytes Potafh Soda	Barytes. potafh. foda.
Lime	lime.
Magnefia Argill	magnefia. argill.
Oxyd of	
zinc	zinc.
iron	iron.
manganefe cobalt	manganefe. cobalt.
nickel	nickel.
lead	lead.
tin	tin.
copper bifmuth	copper. bifmuth.
antimony arfenic	antimony. arfenic
mercury filver	mercury. filver.
gold platina	gold. platina.
  This  order of falts, entirely  unknown to the older che-
mills, was difcovered in 1786 by Mr Berthollet.—A. 
3°4
ELEMENT S
Sect.  XVIII.—Obfervations upon  Muriatic and
  Oxygenated Muriatic  Acids, and their  Combi-
  nations.

  Muriatic  acid is very abundant in the mine-
ral  kingdom, naturally  combined with different
falifiable bafes,  efpecially with  foda, lime, and
magnefia.   In  fea-water, and  the water of fe-
veral lakes, it is combined with  thefe three ba-
fes -, and in  mines of rock-falt it is chiefly united
to foda.   This  acid does  not  appear  to  have
been hitherto  decompofed in any chemical ex-
periment* -,  fo  that we have no idea whatever
ofthe  nature of its radical ■,  and only conclude,
from analogy with the other acids,  that  it con-
tains oxygen as its acidifying  principle.   Mr
Berthollet fufpedts the radical to be of a metallic
 nature.  But, as Nature appears to form this acid
daily in inhabited places, by combining miafmata
with aeriform fluids, this muft neceflarily fuppofe
a  metallic gas to exift  in the atmofphere,  which
 is certainly not impoflible, but cannot be admit-
ted without proof.
  * This fubject has been already mentioned in fome for-
mer notes, where the Lite difcovery of this bi.fe is fitid te
have been  made bv Dr Girtanner.—T. 
OF  CHEMISTRY.
30S
   The muriatic  acid  has  only a moderate ad-
herence  to  the  falifiable bafes,  and can readily
be driven from its  combination with  thefe by
fulphuric acid.  Other acids, as the nitric,  for
inftance, may anfwer che fame purpofe.   But ni-
tric acid  being volatile, would mix, during diftil-
lation, with  the muriatic.   About one part of
fulphuric acid is fufficient to decompofe two parts
of decrepitated fea-falt.  This operation is per-
formed in a tubulated retort, having Woulfe's ap-
paratus,  PI.  IV. Fig. 1. adapted to it.  When all
the junctures are  properly  luted, the fea-falt is
put into  the retort,  through the tube ■, the ful-
phuric acid is poured  on •,  and  the opening  is
immediately  clofed by  its ground cryftal ftopper.
As the muriatic acid can only fubfift in the gaf-
feous form, in the ordinary temperature, we can*
not condenfe it, without the  prefence of water.
Hence the ufe ofthe  water with which the bottles
in Woulfe's apparatus are half filled.   The  muri-
atic acid gas, driven  off from the fea-falt in the
retort, combines  with the  water;  and  forms
what the old  chemifts called fmoaking fpirit of fait,
or Glauber's fpirit of fea-falt,  which we now  name
muriatic acid.
   The acid  obtained  by the above procefs is
ftill capable  of combining with a farther quantity
of oxygen, by being  diftilled from the oxyds  of
manga'nefe, lead,  or  mercury : and the refulting 
306         ELEMENTS

acid, which we  name oxygenated  muriatic acid,
can only,  like the former, exift in the gaffeous
form ;  and is abforbed,  but in  a  much fmaller
quantity,  by water.   When the  impregnation
of water with this gas is pufhed beyond a certain
point, the fuperabundant acid precipitates to the
bottom of the veffels, in a concrete form.   Mr
Berthollet has fhown, that this  acid  is capable
of combining with a great number of the falifi-
able bafes.  The neutral falts which refult from
this union are fufceptible of deflagrating  with
charcoal,  and with  many of the  metallic  fub-
ftances.  But thefe deflagrations are very violent
and dangerous,  owing to the great quantity of
caloric which the oxygen carries along with it
into the  compofition  of oxygenated muriatic
acid*.
  * It has been formerly  mentioned,  that Murioxic acid
would be a more convenient term for this acid, than oxyge-
nated muriatic,  the one adopted in the new nomenclature by
die French chemifts.  In this cafe,  the combinations would
be named Murioxats  of barytes, &c.;  inftead of the much
longer,  and  not more evident,  terms of  oxygenated mu-
riats.—T. 
OF  CHEMISTRY
T'able of the Combinations of  Nitro-muriatic  Acid
   with the Salifiable Bafes,  in  the Order of  Affi-
   nity, fofar as is known.
Names of the Bafes.             Names ofthe Neutral Salts.
Argill	Nitro-muriat o
Ammoniac	ammoniac.
Oxyd of	
antimony	antimony.
filver	filver.
arfenic	arfenic.
Barytes	barytes
Oxyd of	
bifmuth	bifmuth.
Lime	lime.
Oxyd of	
cobalt	cobalt.
copper	copper.
tin	tin.
iron	iron.
Magnefia	magnefia.
Oxyd of	
manganefe	manganefe.
mercury	mercury.
molybdena	molybdena
nickel	nickel.
gold	gold.
platina	platina.
lead	lead.
Potafh	potafh.
Soda	foda.
Oxyd of	
tungftein	tungftein.
zinc	zinc.
  Note—Moft of thefe  combinations, efpecially thofe with
the earths and alkalies, have been little examined : and we are
yet to learn whether they form a mixed  fait, in which the
compound radical remains combined, or if the two acids fe-
parate, to form two diflindt neutral falts.—A. 
308
ELEMENTS
Sect.  XIX.—Obfervations upon the Nitro-Muria-
        tic* Acid, and its combinations.

   The nitro-muriatic acid,  formerly called aqua
regia, is formed by a mixture of nitric and  mu-
riatic acids.   The radicals of thefe two acids com-
bine together,  and form a compound bafe, from
which  an acid is produced, having properties pe- -
culiar  to itfelf, and diftinct from thofe of all other
acids,  efpecially the power of diffolving gold and
platina.
   In diffolutions of  metals  in this acid, as in all
other acids, the  metals are  firft oxydated by at-
tracting a part ofthe oxygen from  the compound
radical.   This occafions a  difengagement of a
particular fpecies of gas, not hitherto defcribed,
which may be called nitro-muriatic gas.   It has a
very  difagreeable fmell, and is fatal to animal
life  when  refpired.  It attacks iron, and caufes
it to ruft.   It is abforbed in confiderable quanti-
ty by  water, which thereby  acquires fome flight
characters  of acidity.   I had occafion to  make
thefe  remarks during a courfe of  experiments

   *  Azo-muriatic would perhaps  anfwer better as a term for
this  compound acid ; Azo-muria  having  been,  in a former
note, propofed as a more convenient name for the bafe than
the more lengthened expreffion of Nitro-muriatic radical.—T. 
         OF  CHEMISTRY.     309

upon platina, in which I diffolved a confiderable
quantity of that metal in nitro-muriatic acid.
  I at firft fufpeCted,  that, in the mixture of ni-
tric  and muriatic  acids,  the  latter attracted  a
part of  the oxygen from  the  former, and  be-
came converted into  oxygenated muriatic acid,
which gave it  the property of diffolving gold.
But  feveral  facts remain  inexplicable upon this
fuppofition.  Were it fo,  we fhould be able to
difengage nitrous gas 6y heating this acid,  which
however does not fenfibly happen.   From thefe
confiderations,  I am  led  to adopt the opinion
of Mr Berthollet, and  to confider  nitro-muria-
tic acid  as a fingle acid, with a  compound bafe or
radical. 
3'0
ELEMEN T S
Table  of the Combinations of Fluoric Acid, with
    the Salifiable Bafes, in the Order of Affinity.
Names of the Bafes	Names ofthe Neutral Salts.
Lime	Fluat of lime*.
Barytes	barytes.
Strontites	ftrontites.
Magnefia	magnefia.
Potafli	potafh
Soda	foda.
Ammoniac	ammoniac.
Oxyd of	
zinc	zinc.
manganefe	manganefe.
iron	iron.
lead	lead.
tin	tin.
cobalt	cobalt.
copper	copper.
nickel	nickel.
arfenic	arfenic.
bifmuth	bifmuth.
mercury	mercury.
filver	filver.
gold	gold.
platina	platina.
         And,  by the dry way,
 Argill                   Fluat of argill.
  Note.—Thefe combinations were entirely unknown to the
old chemifts,  and confequently have no names in the old no-
menclature.—A.
             * Fluor fpar, or Vitreous fpar. 
         OF  CHEMISTRY.      311

 Sect. XX.—Obfervations upon the Fluoric Acid,
               and its combinations.

   Flouric acid exifts ready formed by Nature,
 in  the fluoric  fpars*, combined with calcareous
 earth,  fo as   to  form an infoluble neutral fait.
 To obtain it, difengaged from that combination,
 fluor  fpar, or fluat of lime, is put into a leaden
 retort, with a proper quantity of fulphuric acid.
 A recipient, likewife of lead,  half full of water,
 is adapted, and fire is applied to the retort.   The
 fulphuric acid, from its greater affinity, expels
 the  fluoric acid, which paffes over and is abforb-
 ed by the water in the receiver.   As fluoric acid
 is naturally in  the gaffeous form in the ordinary
 temperature,  we  can receive  it in a pnuemato-
 chemical  apparatus over mercury.  We  are obli-
 ged to employ metallic veffels in  this  procefs -,
 becaufe  fluoric acid diffolves glafs and filiceous
 earth, and  even  renders  thefe  bodies volatile,
 carrying them over with itfelf in diftillation  in the
 gaffeous form.
   We are indebted to Mr Margraff for our firft
 acquaintance with this acid; though, as he could

  * The beautiful fpars from Derbyfhire are of thib kind.
—T. 
3t2         ELEMENTS

never procure  it free from combination  with  a
confiderable quantity of filiceous earth, he was
ignorant of its being an acid fui generis.  The
Duke de Liancourt, under the name of Mr Bou-
langer, has confiderably increafed our knowledge
of its properties,  and Mr Scheele feems to have
exhaufted the  fubject. NThe only thing remain-
ing  is  to endeavour to difcover the  nature of
the fluoric radical, of which we cannot hitherto
form any idea;  as  the acid does not appear to
have been decompofed in any experiment.   It is
only by means of compound affinity chat experi-
ments ought to be made with this view, with any
probability of fuccefs. 
OF  CHEMISTRY.
313
Table  of the Combination of Boracic Acid, with
    the Salifiable Bafes, in the Order of Affinity,
Bafes.	Neutral Salts.
Lime*	Borat of lime.
Barytes	barytes.
Strontites	ftrontites,
Magnefia Potafh	magnefia. potafh.
Soda	foda.
Ammoniac Oxyd of	ammoniac.
zinc	zinc.
iron	iron.
lead	lead.
tin	tin.
cobalt	cobalt.
copper nickel	copper. nickel.
mercury Argill	mercury, argill.
  Note—Moft  of thefe combinations  were neither known,
nor named by the old chemifts.   The boracic acid was for-
merly called fedative fait,  and  its compounds  borax, with
bafe of fixed vegetable alkali, &c.—A.

  * By Dr Hope's experiments, in his  paper on  ftrontites,
read to the Royal Society of  Edinburgh,  lime  follows ba-
rytes ; and the  fuperiority between lime and ftrontites is un-
certain.— T.
                         Rr 
3H
E L EM E N T S
Sect. XXI.—Obfervations upon Boracic Acid,  and
               its Combinations.

  This  is a concrete  acid, extracted  from  a
fait  procured in India,  called borax  or  tincall.
Although borax has been  very  long  employed
in the arts, we  have as yet very imperfect know-
ledge of its origin, and ofthe methods by which
it is extracted  and purified.   There is reafon to
believe it to be  a native fait, found in the earth
in certain parts of the eaft, and  in  the water of
fome lakes.  The whole trade of borax  is in the
hands ofthe Dutch, who  have  been  exclufively
 poffeffed of the art of purifying it, till very lately,
 when Meflts L'Eguillier of Paris have  rivalled
 them in the  manufacture.    But the procefs ftill
 remains a fecret to the world.
   By chemical analyfis we  learn that  borax is
 a neutral fait  with  excefs of bafe, confifting of
 foda, partly faturated with a peculiar acid,  long
 called   Hombergs fedative fait,  now the boracic
 acid.   This acid is found  in an  uncombined ftate
 in the  waters of certain lakes : That of Cherchiais
  in Italy contains 94^ grains in  each pint of wa-
 ter.
    To  obtain  boracic  acid,  diflblve  fome borax
  in boiling water ;  filtrate the folution ;  and add 
OF  C HEMIS T R Y      315
fulphuric  acid, or any other having greater af-
finity to foda than the boracic acid.   This latter
acid is feparated, and is procured in a cryftalline
form by cooling.   This acid  was long confider-
ed as being  formed during the procefs by which
it  is obtained •, and  was  confequently fuppofed
to differ according  to the  nature  of the acid
employed in feparating it from the  foda.   But
ic  is  now univerfally acknowledged, that it is
identically the fame  acid, in whatever way pro-
cured, provided it  be  properly purified  from
mixture of other acids, by wafhing, and by re-
peated folution aud cryftallization.   It is foluble
both in water  and  alkohol, and  has  the pro-
perty of communicating a green colour to the
flame of  that fpirit. This circumftance led to
a  fufpicion of  its  containing copper, which is
not confirmed by any decifive experiment.   On
the contrary, if it contain any of that metal, it
muft only  be confidered as  an accidental mixture.
It combines with the  falifiable bafes in the humid
way;  and  though, in this manner,  it  is inca-
pable  of diffolving any of the  metals directly,
this combination is readily effected by compound
affinity.
  The  Table  prefents  its combinations in the
order of affinity in  the humid way.   But there
is  a confiderable change  in the order, when we
operate via  ficca;   for, in that  cafe,  argill, 
316          ELEMENTS

though  the laft  in our lift,  muft be placed im-
mediately after foda.
   The  boracic  radical  is hitherto unknown, no
experiments  having as  yet been able to decom-
pofe the acid.   But we  conclude, from analogy
with the  other  acids, that  oxygen exifts in its
compofition, as  the acidifying principle. 
OF  CHEMISTRY.
3*7
Table   of  the Combinations  of   Arfenic  Acid,
  with the Salifiable Bafes,  in  the Order of Af-
  finity.
Bafes.	Neutral Salts.
Lime	Arfeniat of lime.
Barytes	barytes.
Strontites	ftrontites.
Magnefia	magrtefia.
Potafh	potafh.
Soda	foda.
Ammoniac	ammoniac.
Oxyd of	
zinc	2inc.
manganefe	manganefe,
iron	iron.
lead	lead.
tin	tin.
cobalt	cobalt.
copper	copper.
nickel	nickel.
bifmuth	bifmuth.
mercury	mercury.
antimony	antimony.
filver	filver.
gold	gold.
platina	platina.
Argill	argill.
   Note.—This order of falts was entirely unknown to the
old chemifts.  Mr Macquer,  in 1746, difcovered the combi-
nations of arfeniac  acid with potafh and foda, to which he
gave the name of arfenical neutralfait7,*—A. 
318        ELEMENTS
Sect. XXII.—Obfervalio is  upon Arfeniac Acid,
              and its Combinations.

  In the Collections of the  Academy for 1746,
Mr  Macquer fhews,  that,  when  a  mixture of
white oxyd of arfenic  and nitre are fubjected to
the action of a ftrong fire, a neutral  fait is ob-
tained,   which he calls neutral fait  of arfenic.
At that time,  the caufe of this lingular pheno-
menon, in which a metal acts the part of an a-
cid,  was quite unknown.   But  more  modern
experiments  teach,  that,  during this  procefs,
the arfenic  becomes  oxygenated,  by  carrying
off the  oxygen  of the  nitric  acid.   It is thus
converted into a real  acid,  and combines with
the potafh.   There  are  other methods now
known for  oxygenating arfenic,  and obtaining
its acid  free from combination.   The moft fim-
ple and  moft  effectual of  thefe is  as  follows:
Diffolve white oxyd  of arfenic  in three parts,
by weight, of muriatic acid.   To this folution, in
a boiling ftate, add  two  parts  of nitric acid,
and evaporate  to  drynefs.   In  this procefs, the
nitric acid isdecompofed ; its oxygen unites with
the  oxyd of  arfenic,  and  converts  it into an
acid j and the nitrous  radical flies off  in the ftate
of nitrous gas j while  the muriatic  acid is con-
verted by the  heat into muriatic acid  gas, and 
OF  CHEMISTRY.      3*9
may be  collected in proper veffels.  The arfe-
niac acid is entirely  freed from the other acids
employed, during the procefs by heating it in a
crucible  till it begins to grow  red.  What re-
mains is pure concrete arfeniac acid.
  Mr  Scheele's  procefs,  which was  repeated
with great fuccefs by Mr Morveau, in the la-
boratory  at Dijon,  is as follows : Diftil muria-
tic  acid  from  the  black oxyd  of  manganefe.
This converts it into oxygenated muriatic acid,
by  carrying off the oxygen from the manganefe.
Receive this oxygenated acid in  a recipient, con-
taining white oxyd of arfenic,  covered by a little
diftilled water.  The arfenic decompofes the oxy-
genated muriatic acid, by carrying off its fuper-
faturation of oxygen, and is converted into arfe-
niac acid, while  the oxygenated muriatic acid'
is brought back to the ftate  of common muriatic
acid.   The  two  acids are feparated by diftilla-
tion with  a  gentle  heat  increafed  towards  the
end of the operation.   The muriatic acid paffes
over, and the  arfeniac acid remains behind in a
white concrete form.
  The arfeniac acid  is confiderably lefs volatile
than white oxyd of arfenic.   It often contains
white oxyd of arfenic in folution, owing to its
not being fufficiently oxygenated.  This is pre-
vented by continuing to add nitrous  acid,  as
in  the former procefs, till no more nitrous gas
is  produced.   From  all  thefe obfervations  I 
320
ELEMENTS
would give  the following definition of arfeniac
acid.  It is a white concrete metallic acid, form-
ed by the combination of arfenic with oxygen j
it is fixed in a red heat, is foluble in water, and is
capable  of combining  with  many  of the fali-
fiable  bafes.


Sect. XXIII.—Obfervations upon Molybdic Acid,
    and its Combinations zvith Acidifiable  Bafes *.

   Molybdena is a particular metallic body,  ca-
pable  of being oxygenated,  fo far as to become
a  true concrete acidf.   For  this purpofe, one
part by weight of the ore of molybdena,  which
)s a natural  fulphuret of that metal, is put into
a retort, with five or fix parts of nitric acid,  di-
luted with a  quarter of its weight of water, and
heat is applied to the retort.  The oxygen of the
nitric  acid  acts  both upon the molybdena and
the fulphur,  converting  the one  into  molybdic,
and the other into fulphuric acid.   Pour on frefh
quantities of nitric acid fo  long as any  red fumes

 * I have  not added the Table of thefe combinations, as the
order of their affinity is  entirely  unknown ;  they are called
molybdats of argill, antimony, potajh, Sec-—T.
  f This  acid  was difcovered by Mr  Scheele, to whom che-
miftry is indebted for the difcovery of feveral  other acids.—^A. 
)
OF  CHEMISTRY.
321
of  nitrous gas  efcape.   The molybdena is then
oxygenated  as far as is poffible;  and is found at
the  bottom  of the retort in a pulverulent form,
refembling  chalk.   It  muft be wafhed in  warm
water,  to feparate any adhering particles of ful-
phuric  acid; and, as it is hardly foluble,  we  lofe
very little of it in this operation.   All its combi-
nations with falifiable bafes were unknown to the
old  chemifts*.
   *  Meffrs Tondi and Ruprecht have lately reduced Molyb-
dena to the reguline ftate, by a fimilar procefs to that former-
ly defcribed for reducing the metals of Chalk, Magnefia,  and
Barytes.  They defcribe the metallic button as being convex
and compact, and refembling fteel in its colour, its fracture
is uneven and granulated, and  has more metallic luftre inter-
nally than on the furface.   It is  brittle, not hard, and not at-
tractive by the magnet.  On the furface of one of the but-
tons procured in thefe experiments,  fome little cavities were
obferved, in which the metal had cryftallized in form of prif-
matic needles, which were too  fmall to allow of their particu-
lar configuration being accurately determined.  The fpecific
gravity of this metal, according to  the experiments of  Mr
Haidinger, councillor of  the Schemnitz mines, is 6.963, wa-
ter being taken as  1.000.—T.
S  f 
322
ELEMENTS
Table  of the Combinations of Tungstic Acid,  with
                the Salifible Bafes.
Bafes.	Neutral Salts.
Lime	Tungftat of lime.
Barytes	barytes.
Magnefia	magnefia.
Potafh	potafh.
Soda	foda.
Ammoniac	ammoniac.
Argill	argill.
Oxyd of	
antimony*, &c.	antimonyj-, &c.
Sect. XXIV.—Obfervations upon  Tungstic Acid,
              and its Combinations.

   Tungftein is a  particular  metal,  the ore of
which has  frequently  been   confounded  with
that of tin.   The fpecific gravity of this  ore is
to water as 6 to i.  In its form of cryftallization
it refembles the  garnet, and varies  in colour

  * The combinations with metallic oxyds  are fet down by
Mr Lavoifier in alphabetical order, their order  of affinity
being unknown.  1 have omitted them as  ferving  no  pur-
pofe.—T.
   f  All thefe falts were unknown to the old chemifts.—A. 
OF CHEMISTRY.
323
 from a  pearl-white to a yellow and  reddifh.   It
 is  found in  feveral parts of Saxony  and Bohe-
 mia.  The mineral called Wolfram,  which is fre-
 quent in  the  mines of Cornwall, is likewife an
 ore of this metal.  In all thefe ores,  the metal is
 oxydated: and,  in  fome of them,  it appears
 even to be oxygenated to the ftate of acid, being
 combined with lime into a true tungftat of lime.
   To obtain the  acid free, mix one part of ore of
 tungftein with four parts of carbonat of  potafh,
 and melt the mixture in a crucible.   Then pow-
 der it, and pour on twelve parts of boiling water;
 add nitric acid, and the  tungftic acid precipitates
 in  a concrete form.  Afterwards,  to infure the
 complete oxygenation of the metal, add more ni-
 tric acid, and evaporate to dryncfs, repeating this
 operation fo long  as red  fumes of nitrous gas are
 produced.  To procure tungftic  acid  perfectly
pure, the fufion of the ore with carbonat of pot-
afh muft  be made  in a crucible of platina; other-
wife the earth of the common crucibles will mix
with the products, and adulterate the acid. 
3*4
ELEMENTS
Table ofthe Combinations of Tartarous Acid, with
    the Salifiable Bafes, in the Order of Affinity.
Bafes.	Neutral Salts.
Lime	Tartarite of lime
Barytes	barytes.
Strontites	ftrontites.
Magnefia	magnefia.
Potafh	potafh.
Soda	foda.
Ammoniac	ammoniac.
Argill	argill.
Oxyd of	
zinc	zinc.
iron	iron.
manganefe	manganefe.
cobalt	cobalt.
nickel	nickel.
lead	lead.
tin	tin.
copper	copper.
bifmuth	bifmuth.
antimony	antimony.
arfenic	arfenic.
filver	filver.
mercury	mercury.
gold	gold.
platina	platina.
 
OF  CHEMISTRY.
3*S
 Sect.  XXV.—Obfervations upon Tartarous Acid,
              and its Combinations.

   Tartar, or the concretion  which fixes to the
 infide of  veffels  in  which the fermentation of
 wine is completed,  is a well known fait, com-
 pofed of a peculiar acid,  united, in confiderable
 excefs,  to potafh.  Mr  Scheele firft pointed out
 the  method of obtaining  this  acid pure.   Ha-
 ving obferved,  that it has a greater affinity to
 lime than  to potafh, he directs  us to proceed in
 the  following manner.   Diffolve  purified tartar
 in boiling water, and  add a fufficient quantity
 of lime, till the  acid  be completely faturated.
 The tartarite of lime, which is thus formed,  be-
 ing  almoft infoluble in cold water, falls to the
 bottom, and is feparated from the  folution of
 potafh  by decantation. . It is afterwards wafhed
 in cold water, and dried.   Then fome fulphuric
 acid, diluted with eight or nine parts of water,
 is poured on.  Digeft for twelve hours in a gen-
 tle heat,  frequently ftirring the mixture, and the
 fulphuric acid combines with the  lime,  leaving
 the   tartarous acid  free.  A fmall quantity of*
 gas,  not hitherto examined,  is difengaged during
 this  procefs.   At the end of twelve hours, ha-
ving decanted off the clear liquor,  wafh the ful-
phat of lime in cold water, which add to  the
decanted liquor ■,  then evaporate  the whole;  and 
 326           ELEMENTS

the tartarous acid is obtained in a concrete form.
Two pounds of purified tartar,  by means of from
eight  to ten ounces of fulphuric acid, yield a-
bout  eleven ounces of  tartarous acid.
   As the combuftible radical exifts in excefs, or
as the  acid from tartar  is not  fully faturated
with  oxygen,  we call it tartarous acid; and  the
neutral  falts, formed by  its combinations with
falifiable bafes, are named tartarites.   The bafe
ofthe tartarous acid is a carbono-hydrous or hy-
dro-carbonous radical, lefs  oxygenated  than in
the oxalic acid -,  and it would appear,  from  the
experiments of Mr Haffenfratz, that azot enters
into  the compofition of  the  tartarous radical,
even in confiderable  quantity.   By  oxygenating
tartarous  acid ftill farther, it is convertible into
oxalic,  malic,  and acetous acids.   But it is pro-
bable the proportions of hydrogen and carbon in
the radical, are changed, during thefe  converfionsj
and that the difference  between thefe acids  does
not alone confift in the different degrees of oxy-
genation.
   The  tartarous acid is  fufceptible of two de-
grees  of faturation in its  combinations with the
fixed alkalies.  By one  of thefe a fait is formed
with excefs  of acid,  improperly  called cream of
tartar, which,  in  our new nomenclature, is na-
med acidulous tartarite  of potafh.   By a fecond
or reciprocal degree of faturation,   a perfectly
neutral  fait  is formed,  formerly  called vegetable 
OF  CHEMISTRY.
327
fait, which we  name tartarite  of potajh.   With
 foda this  acid  forms tartarite of  foda,  formerly
 calledy^/  de Seignette, orfalpolychreft of Rochelle*.

 Sect.  XXVI.—Obfervations  upon   Malic  Acid,
    and its  Combinations with the Salifiable  Bafes-f.

   The  malic  acid  exifts ready formed  in the
 four juice of ripe and unripe apples, and many
 other fruits,  and is obtained as  follows:  Satu-
 rate the juice of apples  with potafh  or foda, and
 add a proper proportion  of acetite  of  lead  dif-
 folved in water ■,  a double decompofition takes
 place,  the malic acid combines  with  the oxyd
 of lead, and precipitates,   being  almoft infoluble j
 and the acetite of potalh or  foda remains  in the
 liquor.  The malat of lead  being feparated  by
 decantation,  is wafhed with cold water, and fome
 diluted fulphuric acid is  added;  this unites with
 the  lead  into an  infoluble fulphat, and the ma-
 lic acid remains free in the liquor.

   * This account of the compofition of Rochelle fait is not
quite accurate.  It is a  triple  fait, confifting of  tartarous a-
cid, faturated by foda and potafh ; and is formed by  com-
pletely neutralizing acidulous tartarite of potafh,  b*y the ad-
dition of a fufficient quantity of foda.—T.
  f I have omitted  the Table, as the order of affinity is
unknown, and is given  by Mr  Lavoifier only  in alphabetical
order.  All  the combinations  of malic acid with  falifiable
bafes, which are named  malats, were unknown  to  the old
chemifts.—T. 
328
ELEMENTS
   This acid,  which is found mixed with citric
and tartarous acid, in a great number of fruits,
is a kind of medium between the oxalic and ace-
tous acids, being more oxygenated than  the for-
mer, and lefs fo than the latter.  From this cir-
cumftance,  Mr Hermbftadt calls it imperfecJ vine-
gar ;  but it differs likewife from acetous  acid, by
having rather  more carbon, and lefs hydrogen,
in the compofition of its radical.
   When an acid much diluted has been ufed in
the foregoing  procefs,  the liquor contains oxalic
as well as malic acid, and probably a little tar-
tarous.  - Thefe are feparated by mixing lime-wa-
ter with  the acids,  oxalat,  tartarite,  and  malat
of lime  are produced.   The two  former, being
infoluble, are precipitated, and the malat of lime
remains diffolved ; from this the pure malic acid
is feparated by the acetite of lead,  and afterwards
by fulphuric acid, as directed above. 
OF   CHEMISTRY.
329
Table  of the Combinations  of Citric  Acid, with
  the Salifiable Bafes, in the Order of Affinity*.
Bafes.	Neutral Salts
Barytes Citrat of barytes.	
Lime	lime.
Magnefia	magnefia.
Potafh	potafh.
Soda	foda.
Ammoniac	ammoniac.
Oxyd of	
zinc	zinc.
manganefe	manganefe.
iron	iron.
lead	lead.
cobalt	cobalt.
copper	copper.
arfenic	arfenic
mercury	mercury.
antimony	antimony.
filver	filver.
gold	gold.
platina	platina.
Argill	argill.
   * Thefe combinations were unknown to the old chemifts.
The order of affinity of the falifiable bafes with this acid was
determined by Mr Bergman, and by Mr  de Breney of the
Dijon Academy.—A.
                       Tt 
33°
ELEMENTS
Sect. XXVII.—Obfervations  upon Citric  Acid,
              and its Combinations.

  The citric  acid is procured by expreffion from
lemons, and is found in the juices of many other
fruits, mixed with malic acid.  To obtain it pure
and concentrated, it is  firft allowed to depurate
from  the mucous part of the fruit, by long reft
in a cool cellar, and is afterwards concentrated
by  expofing it to the temperature of  from 210
to 23 ° of Fahrenheit.  The water  is thereby fro-
zen, and the  acid  remains  liquid, reduced to
about  an eighth part  of  its original bulk.  A
lower degree  of cold  would  occafion  the acid
to be engaged among the  ice,  and render it dif-
ficultly feparable.   This procefs was pointed out
by Mr Georgius.
   It is more  eafily obtained  by faturating the
lemon-juice with lime, fo as  to form a citrat of
lime, which is infoluble in water.  Wafh this fait,
and pour on a proper quantity  of fulphuric acid.
This forms a fulphat of lime, which precipitates
and leaves the citric acid free in the liquor. 
OF  CHEMISTRY.
33l
Table of the Combinations of Pyro-lignous Acid	
with the Salifiable	Bafes, in the Order of
Affinity*.	
Bafes.	Neutral Salts.
Lime	Pyro-lignite of lime.
Barytes	barytes.
Potafh	potafh.
Soda	foda.
Magnefia	magnefia.
Ammoniac	ammoniac.
Oxyd of	
zinc	zinc.
manganefe	manganefe.
iron	iron.
lead	lead.
tin	tin.
cobalt	cobalt.
copper	copper.
nickel	nickel.
arfenic	arfenic.
bifmuth	bifmuth.
mercury	mercury.
antimony	antimony.
filver	filver.
gold	gold.
platina	platina.
Argill	argill.
  * The above affinities  were
Morveau and  Eloi Bourfier de
tions were entirely unknown till
 determined by  Meffrs  de
Clervaux.   Thefe combina-
lately.—A. 
332
ELEMEN TS
 Sect. XXVIII.—Obfervations upon the Pyro-lignous
           Acid, and its Combinations.

   The old chemifts obferved, that moft of the
 woods, efpecially the more heavy  and compact
 ones, give out a particular  acid  fpirit,  by dif-
 tillation in a naked fire.  But, before Mr Goet-
 ling, who gives an account of  his experiments
 upon this fubject in Crell's Chemical Journal for
 1779, no one had ever made any inquiry into its
 nature and properties.  This acid appears to be
 the fame, whatever be the  wood it is  procured
 from.   When firft diftilled, it is of a brown co-
 lour, and confiderably impregnated with carbon
 and  oil.  It  is purified from thefe by a fecond
 diftillation.   The pyro-lignous  radical is chiefly
 compofed of hydrogen and carbon.

 Sect. XXIX.—Obfervations upon  Pyro-tartarous
  Acid, and its Combinations with the Salifiable Ba-
  fes*.

  The  name  of  Pyro-tartarous  Acid is given to
 a diluted empyreumatic acid, obtained from puri-

  * The order of affinity of the falifiable bafes with this a-
cid, is hitherto unknown.   Mr Lavoifier,  from its fimilarity 
         O  F  C H E M I S T R Y.      333

 £ed acidulous tartarite of potafh, by diftillation
 in a naked fire.  To  obtain  It, let  a retort be,
 half-filled with powdered tartar; adapt  a tubu-
 lated recipient, having a bent tube communica-
 ting with a bell-glafs in a pneumato-chemical
 apparatus.   By gradually raifing the fire under
 the retort,  we  obtain the pyro-tartarous  acid
 mixed with oil, which is feparated  by means of
 a funnel.  A vaft quantity of carbonic acid  gas
 is difengaged during the diftillation.   The  acid
 obtained by  the above  procefs, is much contami-
 nated with oil, which ought to be feparated from
 it.  Some authors advife to do this by a fecond
 diftillation ;  but the Dijon academicians  inform
 us, that this is attended with great danger, from
 explofions which take place during the procefs.


 to pyro-lignous acid, fuppofes the order to be the fame in
both ; but, as this  is not  afcertained  by experiment, the
table is omitted.  All  thofe combinations, called  Pyro-tar-
tarites, were unknown till lately.—T. 
334
ELEMENTS
Table  of the  Combinations  of Pyro-mucous Acid,
with the Salifiable Bafes, in the Order of Affinity*.
Bafes.                 Neutral Salts.
Potafh Pyro-	■mucite of potafh.
Soda	foda.
Barytes	barytes
Lime	lime.
Magnefia	magnefia.
Ammoniac	ammoniac.
Argill	argill
Oxyd of	
zinc	zinc.
manganefe	manganefe.
iron	iron.
lead	lead.
tin	tin.
cobalt	cobalt.
copper	copper.
nickel	nickel.
arfenic	arfenic.
bifmuth	bifmuth.
antimony	antimony.
  * All thefe combinations were unknown  to the old che^
mills.—A. 
OF  CHEMISTRY.       33S
Sec. XXX.—Obfervations upon Pyro-mucous Acid,
              and its Combinations.

  This acid is obtained by diftillation in a naked
fire from  fugar, and  all the faccharine bodies j
and, as thefe fubftances fwell greatly  in  the
fire, it is neceffary to leave feven-eighths  ofthe
retort empty.   It is of a yellow colour, verging
to red, and leaves a mark upon the fkin,  which
will not remove but  along  with the epidermis.
It may be procured lefs coloured, by means of
a fecond  diftillation;  and is concentrated  by
freezing,  as is directed for the citric acid.   It is
chiefly compofed of water and oil,  flightly oxy-
genated ;  and is convertible into oxalic and ma-
lic acids,  by  farther oxygenation with the nitric
acid.
  It has been pretended, that a large quantity of
gas is  difengaged during the diftillation of  this
acid, which is not the cafe,  if it be conducted
flowly, by means of moderate heat. 
336         ELEMENTS
Table ofthe Combinations of the Oxalic Acid, with
    the Salifiable Bafes, in the Order of Affinity*.
Safes.	Neutral Salts.
Lime	Oxalat of lime.
Barytes Strontites	barytes. ftrontites.
Magnefia Potafh	magnefia. potafh.
Soda	foda.
Ammoniac	ammoniac.
Argill Oxyd of	argill.
zinc	zinc.
iron	iron.
manganefe cobalt	manganefe. cobalt.
nickel	nickel.
lead	lead.
copper bifmuth	copper. bifmuth.
antimony arfenic	antimony. arfenic
mercury filver	mercury. filver.
gold platina	gold. platina.
* All unknown to the old chemifts.—A. 
OF  CHEMISTRY.
337
 Sect. XXXI.—Obfervations upon  Oxalic Acid,
              and its Combinations.

   The oxalic acid is moftly prepared in Switzer-
 land  and  Germany from the expreifed juice of
 forrel, from which it cryftallizes by being left
 long  at reft.  In this ftate it is partly faturated
 with  potafh, forming a true acidulous oxalat of
 potafh, or fait with  excefs of acid.    To obtain
 it pure, it muft be formed artificially by oxyge-
 nating fugar, which feems to be the true oxalic
 radical.  Upon one  part of fugar,  pour fix or
 eight   parts of nitric acid, and  apply a  gentle
 heat,   a confiderable effervefcence  takes place,
 and a great quantity of nitrous gas is difengaged.
 The nitric acid is decompofed,  and its oxygen
 unites  to the fugar.  By  allowing the  liquor
 to ftand at reft, cryftals of pure  oxalic acid are
 formed, which muft be dried upon blotting paper,
 to feparate any remaining portions of nitric acid;
 and, to  enfure the purity of the acid,  diffolve
the cryftals in diftilled water, and cryftallize them
afrefh.
   From the liquor remaining after the firft cryf-
tallization of the oxalic  acid,  we  may  obtain
malic  acid  by refrigeration.   This acid is more
oxygenated than  the oxalic;  and by a further
                     Vv 
338'         ELEMENTS

oxygenation, the fugar is convertible into acetous
acid, or vinegar.
  The oxalic acid, combined with a fmall quantity
of foda or potafh,  has the property,  like  the
tartarous acid, of entering into a number of com-
binations without fuffering decompofition.  Thefe
combinations  form  triple  falts,  or neutral falts
with double bafes,  which ought to have proper
names.    The fait  of forrel,  which  is potafh
having oxalic acid combined in excefs, is named
acidulous oxalat  of potafh, in our new nomencla-
ture.
  The acid procured from forrel has been known
to chemifts for more than  a  century, being men-
tioned by Mr DucIqs in the Memoirs of the
Academy for 1688 j and was pretty accurately
defcribed by Boerhaave.   But Mr Scheele firft
fhewed that it contained potafli, and demonftrated
its identity with  the acid formed by the oxygena-
tion of fugar.


Sect. XXXII.—Obfervations upon Acetous Acid,
             and its Combinations.

   This acid is compofed of  carbon and hydrogen
united  together,   and   brought to  the  ftate
of  an acid by  the addition of oxygen.   It is
 confequently formed of  the  fame elements with
 the tartarous, oxalic, citric, and malic acids, and 
To face page 338.
        TABLE of the Combinations  of Acetous Acid with  the Salifiable  Bafes in the Order of Affinity.
Bafes.
Neutral Salts.
Barytes  -

Potafh

Soda
Lime
Magnefia
Ammoniac
Oxyd of zinc   -
-------manganefe
------. iron
-------lead
Argill
 tin  -  -
 cobalt
 copper  -
 nickel
 arfenic  -

■ bifmuth

■ mercury
• antimony
. fdver
- gold    -
- platina
Acetite of barytes

   ■      potafh
 foda

 lime
 magnefia
 ammoniac
 zinc
 manganefe
 iron
 lead
 tin   -   -
 cobalt
 copper  -
■ nickel
 arfenic  -

■ bifmuth

• mercury

. antimony
- filver
              Names of the refulting Neutral Salts, according to the Old Nomenclature.

I  Unknown to the old chemifts.  Difcovered by Mr de Morveau,  who calls it bmrttic ami.
C Secret  terra foliata tartari,  of Muller.   Arcanum tartari, of Bafil Valentin and Paracelfus.
J   Purgative magiftery of tartar, of Schroeder.  Effential  fait  of  wine of Zwelfer.  Regt-
I   nerated tartar, of Tachenius. Diuretic fait, of Sylvius and Wilfon.
  {Foliated  earth with  bafe of mineral alkali.   Mineral or  cryltallifable  foliated earth.   Mi-
    neral acetous fait.
  Salt of chalk, coral,  or crabs eyes; mentioned by Hartman.
  Firft mentioned by Mr Wenzel.
  Spiritus Mindereri.  Ammoniacal acetous fait.
  Known to Glauber, Schwedemberg,  Refpour, Pott, de LafTone, and Wenzel, but not named.
  Unknown to the old chemifts.
  Martial vinegar.   Defcribed by Monnet,  Wenzel, and the Duke d'Ayeu
  Sugar, vinegar, and fait, of lead or of Saturn.
  Known to Lemery, Margraff, Monnet, Weflendorff, and Wenzel, but not named.
  Sympathetic ink of Mr Cadet.
 | Verdigris, cryttaU of verditer, verdi.er, diffiiled Verd.gm,  crynal, of \ enu, or of coppe.
  Unknown to the old chemifts.




 •   ,748  i known.o Hdot,  Margraff, Baume, Bergman,
   Unknown.                               , . „ni,nown to the oli chemifts.
   Defcribed by Margraff, Monner, ^"f-^T
   Liale known, mentioned by Scheroeder and ]uncker.
 
OF  CHEMISTRY.
339
 others:  but the elements exift in different pro-
 portions in each of thefe ;  and it would  appear
 that  the acetous  acid  is  in  a higher  ftate of
 oxygenation than thefe other acids.  I have fome
 reafon to believe that the acetous radical contains
 a fmall portion of azot;  and, as this  element
 is not contained in the  radicals of any vegetable
 acid,  except  the  tartarous,  this circumftance
 is one of the caufes of difference.  The acetous
 acid, or vinegar,  is produced by expofing wine
 to  a  gentle  heat,  with the  addition of fome
 ferment.   This is ufually the  ley,  or  mother,
 which has feparated from other  vinegar during
 fermentation,  or  fome fimilar   matter.   The
 fpirituous  part of the  wine,  which  confifts of
 carbon and hydrogen,  is oxygenated, and con-
 verted into vinegar.  This operation can only
 take  place with free  accefs of air, and is always
 attended by  a  diminution of  the  air  employed,
 in  confequence of the  abforption of oxygen;
 wherefore it  ought always  to be  carried  on in
 veffels only  half  filled  with the vinous liquor
 fubmitted to the acetous fermentation.
   The acid formed during  this procefs,  is very
 volatile.   It  is mixed with  a  large proportion of
 water, and with many foreign fubftances :  and
 to obtain it pure,  it muft be diftilled, in  ftone or
glafs veffels,  by a  gentle fire.   The acid which
paffes over  in diftillation, is fomewhat changed
by the procefs; and is not  exactly of the fame 
340
ELEMENTS
nature with what remains in the alembic, but
feems  lefs oxygenated.   This circumftance has
not been formerly obferved by chemifts.
   Diftillation  is not fufficient for depriving this
acid of all its unneceffary water; and,  for this
purpofe, the beft way is by expofmg it to a degree
of cold,  of from ic/to 230 of Fahrenheit.  By
this means the aqueous part becomes frozen, and
leaves the acid in a liquid ftate, and confiderably
concentrated.    In  the  ufual  temperature  of
the  air,  this acid  can  only exift  in the  gaffeous
form,  and can only be retained  by combination
with a large proportion of water.   There are
other chemical proceiTes for obtaining the acetous
acid, which confift in  oxygenating the tartarous,
oxalic,  or malic  acids,  by  means of nitric
acid.  But there is reafon to believe the propor-
tions of the elements of the radical are changed
during this   procefs.    Mr.  Haffenfratz is  at
prefent engaged in repeating  the experiments
by which thefe converfions  are faid  to be pro-
duced.
   The  combinations  of acetous acid with the
various  falifiable bafes are very readily formed.
But moft of  the  refulting neutral falts are not
cryftallizable  ; whereas  thofe produced by the
 tartarous and oxalic acids are, in general, hardly
 foluble.   Tartarite and  oxalat of lime are not
 foluble  in any fenfible degree.   The malats are
 a  medium between  the oxalats  and  acetites, 
OF  CHEMISTRY.      341
with refpect to folubility,  and the malic acid is
in the middle  degree of faturation between  the
oxalic and acetous acids.   With this, as with all
the acids, the metals require to  be oxydated
previous to  folution.
  The  older chemifts knew  hardly any of  the
falts formed by the combinations of acetous acid
with the falifiable bafes,  except  the acetites of
potafh, foda, ammoniac, copper, and lead.   Mr
Cadet difcovered  the acetite of  arfenic*.  Mr
Wenzel,  and the  Dijon  academicians, Mr de
Laffone and Mr Prouft, made us acquainted with
the properties of the other acetites.   From the
property which  acetite of  potafh  poffeffes, of
giving out ammoniac  in diftillation, there is fome
reafon to fuppofe, that befides carbon and hydro-
gen, the acetous radical contains a fmall proportion
of azot; though it is not impoflible but the above
production of  ammoniac may be  occafioned by
the decompofition of the potafh.
* Savans Etrangers, Vol. III. 
342
ELEMENTS
Table of the Combinations of Acetic Add, with
   the Salifiable Bafes, In the Order of Affinity.
Bafes.	Neutral Salts.
Barytes	Acetat of barytes.
Potafh	potafli.
Soda	foda.
Lime	lime.
Magnefia	magnefia.
Ammoniac	ammoniac.
Oxyd of zinc	zinc.
manganefe	manganefe.
iron	iron.
lead	lead.
tin	tin.
cobalt	cobalt.
copper	copper.
nickel	nickel.
arfenic	arfenic.
bifmuth	bifmuth.
mercury	mercury.
antimony	antimony.
filver	filver.
gold	gold.
platina	platina.
Argill	argill.
  Note.—All thefe falts were unknown to the older chemifts:
And even thofe,  who are moft verfant in modern difcoveries,
are yet at a lofs whether the greater part of the falts produced
by the oxygenated acetic radical belong properly to the clafs of
acetites, or to that of acetats.—A. 
OF  CHEMISTRY.
343
 Sect. XXXIII.—Obfervations upon Acetic Acid,
              and its Combinations.

   We have given to radical vinegar the name of
 acetic acid, from fuppofing that it confifts of the
 fame radical with  that of  the  acetous acid, but
 more highly faturated with oxygen.  According
 to this idea, acetic acid is  the higheft degree of
 oxygenation of which the hydro-carbonous radical
 is fufceptible; but, although this circumftance be
 extremely probable,  it requires to be confirmed
 by farther and more decifive experiments, before
 it be adopted as  an abfolute chemical truth.
 We procure this acid as  follows:  Upon three
 parts acetite  of potafh  or of copper, pour  one
 part of concentrated fulphuric acid, and, by diftil-
 lation, a  very highly concentrated vinegar is
 obtained, which we call acetic acid, formerly named
 radical vinegar.   It  is  not  hitherto rigoroufly
 proved, that this acid is more highly oxygenated
 than the acetous  acid,  nor  that the  difference
between them may not confift in a different propor-
tion between the elements of the  radical or bale. 
344
ELEMENTS
Table of the combinations of Succinic Acid  with
  the Salifiable Bafes, in the Order of Affinity.
Bafes.	Neutral Salts.
Barytes Lime	Succinat of barytes. lime.
Potafh Soda	potafh. foda.
Ammoniac	ammoniac.
Magnefia Argill Oxyd of zinc	magnefia. argill. zinc.
iron	iron.
manganefe cobalt	manganefe cobalt.
nickel	nickel.
lead	lead.
tin	tin.
copper bifmuth	copper. bifmuth.
antimony arfenic	antimony. arfenic.
mercury filver	mercury. filver.
gold
platina
gold.
platina.
  Note.—All the fuccinats were unknown to the older chemifts.
—A. 
OF  CHEMISTRY.     345
  Sect. XXXIV.—Obfervations upon Succinic Acid,
               and its Combinations.

    The fuccinic acid is drawn from amber by fub-
 limation in a gentle heat; and rifes,  in a concrete
 form, into the neck of the fubliming veffel.   The
 operation muft not be puflied too far, or by too
 ftrong a  fire, otherwife the oil of the  amber rifes
 with the acid.   The fait  is dried  upon blotting
 paper, and  purified  by repeated folution  and
 cryftallization.
   The acid is foluble in  twenty^four times its
 weight of cold water,  and in a much fmaller
 quantity of hot water.   It poffeffes the qualities
 of an acid in  a very fmall degree, and only affects
 the  blue  vegetable colours very flightly.   The
affinities of this acid, with the falifiable  bafes  are
taken from Mr de Morveau, who is the firft chemift
that has endeavoured  to afcertaia them,
Xx 
346
ELEMENTS
Sect. XXXV.—Obfervations upon Benzoic Acid^
   and its Combinations with Salifiable Bafes*.
  This  acid was known to  the ancient chemifts
under the name of  the Flowers of Benjamin, or
of Benzoin,  and was procured  by fublimation,
from the  gum or  refin called  Benzoin.   The
means of procuring it,  via humida, was difco-
vered by Mr Geoffroy,  and perfected by Mr
Scheele.  Upon  benzoin,  reduced  to  powder,
pour ftrong lime-water, having rather  an excefs
of lime.  Keep the mixture continually ftirring;
and, after half an hour's digeftion, pour  off fhe
liquor,  and ufe frefh portions of lime-water  in
the fame manner, fo long as there is any appearance
of neutralization.   Join all the decanted  liquors,
 and evaporate as far as  poffible, without occa-
 fioning  cryftallization;  and, when the liquor
 is  cold,  drop  in muriatic acid, till no more
 precipitate is formed.   By the former part of the
 procefs a benzoat of lime  is formed;  and,  by
 the latter,  the muriatic acid combines with the
 lime,  forming muriat  of  lime,  which  remains

   * Thefe combinations are called Benzoats of Lime, Potafh,
 Zinc, &c ; but, as the order of affinity is unknown, the-
 alphabetical table is omitted, as unneceftary.—-T. 
         OF  CHEMISTRY.      347

diffolved, while the benzoic acid, being infoluble,
precipitates in a concrete form.
 Sect. XXXVI. — Obfervations  upon  Camphoric
   Acid,  and its Combinations  with Salifiable Ba-
   fes*.

   Camphor is a concrete effential oil, obtained,
 by fublimation, from a fpecies of laurus  which
 grows in China and Japan.   By diftilling nitric
 acid eight times from camphor,  Mr Kofegarten
 converted it into an acid, analogous to the oxalic.
 But, as it differs from that acid  in fome circum-
 ftances,  we have  thought  neceffary to give  it a
 particular name, till its nature be more completely
 afcertained by farther experiment.
   As camphor is  a carbono-hydrous or hydro-
 carbonous radical,  it is eafily conceived,  that,
 by oxygenation, it fhould  form  oxalic,  malic,
 and  feveral other  vegetable acids.  This conjec-
 ture is  rendered not  improbable  by the experi-
 ments  of  Mr Kofegarten;  and the principal
 phenomena exhibited  in  the  combinations  of
 camphoric acid with the falifiable bafes,   being

  * Thefe  combinations, which  were all unknown  to  the
old chemifts, are called Camphorats.  The table is omitted*
as being only in alphabetical order.—T. 
34$          ELEMENTS

very fimilar to thofe of the oxalic and malic acids,
lead me to believe, that it confifts of a mixture of
thefe two acids.
 Sect. XXXVII.—-Obfervations upon Gallic Acid,
   and its Combinations with Salifiable Bafes *.


   The Gallic acid, formerly called the Principle
 of Aftringency, is obtained from gall-nuts, either
 by infufion or decoction with water, or by dif-
 tillation   with  a very gentle heat.   This acid
 has  only been  attended  to within  thefe few
 years.   The committee  of the  Dijon Academy
 have followed it  through  all its combinations,
 and  give  the  beft account  of it hitherto pro-
 duced.    Its acid properties are very weak.   It
 reddens   the  tincture  of  turnfol;   decompofes
 fulphurets; and unites to all the metals,  when
 they have been previoufly diffolved in fome- other
 acid.  Iron, by  this combination, is  precipitated
 of a very deep blue or violet colour.   The radi-
 cal of this acid, if it  deferve the name of one,
 is hitherto entirely unknown : it is contained in

  * Thefe combinations, which are called Gallats, were all
unknown to the older chemifts ; and the order of their affinity
is not hitherto eftablifhed.—A. 
        OF  CHEMJSTRY.      349

oak, willow, marfti iris, the ftrawberry, nymphea,
Peruvian bark, the flowers and bark of pomegranate
and in many other woods and barks.
 Sect. XXXVIII.—Obfervations uponLaclic Acid,
    and its Combinations with Salifiable Bafes*.


   The only accurate knowledge we have of this
 acid  is from the works of Mr Scheele.   It  is
 contained in whey,  united  to a  fmall  quantity
 of earth,  and is  obtained  as follows: Reduce
 whey to one eighth part of its bulk by evaporation,
 and filtrate, to feparate all  its cheefy matter.
 Then add as much  lime as  is  neceffary to
 combine with the acid.   The lime is afterwards
 difengaged by the addition of oxalic acid,  which
 combines with it into an infoluble neutral  fait.
 When the oxalat of lime has been feparated by
 decantation, evaporate the remaining  liquor to
 the confiftence of honey.   The lactic acid is dif-
 folved by  alkohol,  which  does  not unite with
 the  fugar  of milk  and  other foreign  matters.
 Thefe are feparated  by filtration from the alkohol

  * Thefe combinations  are called Ladtats. They were all
unknown  to the older chemifts; and their affinities have not
yet been afcertained.—A. 
35°
ELEMENTS
and acid :  and the alkohol being evaporated or
diftilled off, leaves the lactic acid behind.
   This acid unites with  all the falifiable bafes,
forming  falts which do not cryftallize; and  it
feems confiderably to refemble the acetous acid. 
OF  CHEMISTRY.
35*
Table of the Combinations of Saccho-laBic Acid
  with the  Salifiable Bafes,  in the  Order  of
  Affinity.
Bafes.	Neutral Salts.
Lime	Saccholat of lime.
Barytes	barytes.
Magnefia	magnefia.
Potafh	potafh.
Soda	foda.
Ammoniac	ammoniac.
Argill	argill.
Oxyd of zinc	zinc.
manganefe	manganefe.
iron	iron.
lead	lead.
tin	tin.
cobalt	cobalt.
copper	copper.
nickel	nickel.
arfenic	arfenic.
bifmuth	bifmuth.
mercury	mercury.
antimony	antimony.
filver	filver.
Note.—All thefe were unknown to the older chemifts.—A. 
ELEMENTS
Sect.  XXXIX.—Obfervations upon Saccho-kftk
          Acid, and its Combinations.

  A fpecies of fugar may be  extracted,  by eva-
poration,  from whey.   This fubftance has long
been  known  in pharmacy, and has  a  confide-
rable refemblance  to  that procured from the
fugar-cane.    This  faccharine  matter, like or-
dinary fugar, may be oxygenated by means of
nitric acid.   For this purpofe, feveral portions of
nitric acid are diftilled  from it.   The remaining
liquid  is  evaporated,  and fet to cryftallize, by
which means cryftals  of oxalic  acid  are procu-
red.  At the fame  time a very  fine white pow-
der precipitates, which  is the faccho-lactic acid
difcovered by Scheele.  It is  fufceptible of com-
bining  with  all  the  alkalies, with the earths,
and even with the  metals.  Its  action upon the
latter  is hitherto  but  little known, except that,
with them,  it forms  difficultly  foluble  falts.
The order of affinity  in the table  is taken from
Bergman. 
OF  CHEMISTRY.      353
Table of the Combinations of Formic Acid with
  the Salifiable Bafes, in the Order of Affinity.
Bafes.	Neutral Salts.
Barytes Potafli Soda	Formiat of barytes. potafli. foda.
Lime	lime.
Magnefia Ammoniac	magnefia. ammoniac.
Oxyd of	
zinc manganefe	zinc. manganefe.
iron	iron.
lead	lead.
tin	tin.
cobalt	cobalt.
copper nickel	copper. nickel.
bifmuth	bifmuth*
filver Argill	filver. argill.
                Yy

fate—All unknown to the older chemifts.—A. 
354
ELEMENTS
Sect. XL.—Obfervations  upon Formic Acid, and
               its Combinations.

  This acid  was firft obtained, by  diftillation
from ants j in the laft century, by Samuel Fifher.
The fubject was treated of by Margraff, in 1749,
and by. Meffrs Ardwiffon and Ochrn of Leipfic,
in 1777.  The formic acid is extracted from a
large  fpecies  of  red ants,  formica  rufa,  Lin.
which'form large ant hills in woody' places.   It
is procured, either  by diftilling  the ants with a
gentle heat in a glafs retort or  an alembic;  or,
after having wafhed  the ants in  cold water, and
dried them upon  a cloth,  by pouring on boiling
water, which diffolves the acid;  or the acid may
be  procured  by  gentle  expreffion   from  the
infects, in which cafe it is ftronger than in any
of the former ways.   To obtain it pure, we muft
rectify, by means of diftillation, which feparates
it from the uncombined oily and charry matter;
and it may be concentrated  by freezing, in the
manner recommended for treating the  acetous
acid. 
OF  CHEMISTRY.
3rf
 Sect. XLI.—Obfervations upon Bombic Acid, and
     its Combinations with Acidifiable Bafes *.

   The juices of the filk-worm feem to affume an
acid quality when  that  infect changes  from the
larva to  the chryfalis ftate.   At the moment of
its efcape from the latter to the butterfly form,
it emits a  reddifh liquor,  which  reddens blue
paper, and  which was firft attentively obferved
by Mr Chauflier of the Dijon Academy.  He
obtained the acid by infufing filk-worm chryfalids
in alkohol,  which diffolves their  acid without
being  charged  with  any of  the gummy parts
of the infect; and,  by evaporating  the alkohol,
the acid remains tolerably pure.  The properties
and affinities of this acid are  not hitherto afcer-
tained with  any precifion:  and we  have reafon
to believe, that analogous acids may be  procured
from  other  infects.   The  radical  of  this acid
is probably, like that of the other  acids from
the animal  kingdom,  compofed of carbon,  hy-
drogen, and azot., with the addition,  perhaps, of
phofphorus,


  * Thefe combinations,  named Bombats,  were unknown
to the old chemifts; and the affinities of the falifiabk bafes
 -th the bombic acid are hitherto undetermined.—A. 
'35*
ELEMENTS
Table of the Combinations of the Sebacic  Acid,
  with the Salifiable Bafes,  in the  Order  of
  Affinity.
Bafes.	Neutral Sabs.
Barytes	Sehat of barytes.
Potafli	potafli.
Soda	foda.
Lime	lime.
Magnefia	magnefia.
Ammoniac	ammoniac.
Argill	argill.
Oxyd of	
zinc	zinc.
manganefe	manganefe*
iron	iron.
lead	lead.
tin	tin.
cobalt	cobalt.
copper	copper.
nickel	nickel.
arfenic	arfenic.
bifmuth	bifmuth.
mercury	mercury.
antimony	antimony.
filver	filver.
Note.—All thefe were unknown to the old chemifts.—A. 
OF  CHEMISTRY.      357
 Sect, TLll.-^>Obfervations upon Sebacic Acid,
             and its Combinations.

  To obtain the febacic acid, let fome fuet be
inched  in  a fldllet over  the fire,  with fome
quick-lime  in fine powder, and  conftantly ftir-
red, raifing  the fire  towards the  end of  the
operation,  and taking  care to  avoid the vapours,
which  are  very offenfive.   By this procefs  the
febacic acid unites with the lime  into a febat of
lime, which is difficultly foluble in water.  It is,
however, feparated from the  fatty matters with
which  it is mixed by folution  in a large quantity
of boiling water.  From this  the neutral fait is
feparated by evaporation; and, to render it pure,
is calcined,  re-diffolved, and  again  cryftallized.
After this we pour on a proper quantity of ful-
phuric acid, and the febacic acid paffes over by
diftillation. 
358           ELEMENTS
 Sect. XLIII.—Obfervations upon the Lithic Acid,
  and its Combinations with the Salifiable Bafes *.


   From the later  experiments of Bergman  and
 Scheele,  the urinary  calculus appears to be a
 fpecies of fait with an earthy bafis.   It is flighty
 acidulous, and requires a large quantity of water
 for folution,  three grains being  fcarcely foluble
 in a thoufand parts of boiling water;  and  the
 greater part  again cryftallizes when  cold.   To
 this concrete acid,  which Mr De Morveau  calls
 the Lithiafic, we give  the name of  Lithic Acid,
 the nature and properties of which  are hitherto
 very  little known.  There is fome appearance
 that  it is an acidulous  neutral fait, or  acid
combined in  excefs with a falifiable  bafe ; and I
have reafon to believe, that it really is an acidulous
phofphat of lime ;  if fo, it muft be excluded from
the clafs of peculiar acids.

  * All the combinations of this acid, fhould it finally turn
out to be one, were unknown to the  older chemifts ; and its
 affinities  with the falifiable  bafes have not been  hitherto
determined. —A. 
OF  CHEMISTRY.
359
Table of the Combinations of the Pruffic Acid,
   with the  Salifiable  Bafes,   in the  order  of
   Affinity *.
Bafes.	Neutral Salts.
Potafh Pruffiat of potafh.	
Soda	foda.
Ammoniac	ammoniac.
Lime	lime.
Barytes Magnefia	barytes. magnefia.
Oxyd of zinc	zinc.
iron	iron.
manganefe cobalt	manganefe. cobalt.
nickel	nickel.
lead	lead.
tin	tin.
copper bifmuth	copper. bifmuth.
antimony arfenic	antimony. arfenic.
filver	filver.
mercury gold	mercury. gold.
platina	platina.
All thefe were unknown to former chemifts,—A. 
360           ELEMENTS
Sect. XLIV.—Obfervations upon the Pruffic Acid,
             and its Combinations.

  As the experiments which have  been made '
hitherto upon  this acid feem ftill  to leave a con-
fiderable degree  of  uncertainty with regard to
its nature, I fhall not enlarge upon its properties,
and the means of procuring it pure and difengaged
from  combination.   It  combines  with  iron to
which it communicates a  blue colour; and  is
equally fufceptible of entering  into combination
with moft of the other metals, which are precipi-
tated from  it  by the alkalies, ammoniac, and
lime, in  confequence of greater  affinity.   The
Pruffic radical, from the experiments of Scheele,
and efpecially from thofe of Mr Berthollet, feems
compofed of carbon and azot; hence it is an acid
with a double bafe.   The phofphorus,  which has
been found  combined with it, appears, from the
experiments of  Mr  Haffenfratz,  to be  only
accidental.
   Although this acid combines with  alkalies,
earths, and metals, in the  fame way with other
acids, it poffeffes only fome of the properties we
have been  in ufe to attribute to acids: and it
may  confequently  be improperly ranked  here
in the clafs of acids.  But,  as  I have already
obferved, it is difficult to form a  decided opinion 
          OF  CHEMISTRY.      361

upon the nature of this fubftance, until the fubjea
has been farther elucidated by a greater number
of experiments.
  Sect. XLV—Recapitulation  of  the  foregoing
     Obfervations  on  the Acids, and their Combina-
     tions *.

     It was thought,  that it might be conducive to
  the convenience and information of the  reader,
  to fubjoin the two  following tables. ■ The firft'
  which is  only a recapitulation of  what is con!
  tamed in  the  foregoing fedtions, gives  a  Gene-
  ral view of the order of the affinities of the fali-
 fiable bafes with the feveral acids, fo far as is
 hitherto known.   Such acids as  have a fimilar
 order of affinity with  thefe bafes, are placed
 together at the head of the fame column ; and
  hofe  of which  the  order of affinity, between
them  and  the-bafes, have not  been  hitherto
alcertamed,  are omitted.
  The  fecond  table contains  a fpecirren  of a
general view of the new  chemical nomenclature
as applied to  the neutral  falts, both in Latin
                    Zz 
362
ELEMENTS
and  Englifh.   The firft column contains the
names of the feveral acids; the fecond is a lift of
the Latin  terms for the neutral falts which thefe
produce by union with the falifiable bafes, as pro-
pofed in the new French chemical nomenclature;
the third is a fyftematic tranflation of thefe terms
into  Englifh, on  exactly  analagous   principles;
the fourth contains another fyftem of Latin no-
menclature, founded on that of the French che-
mifts, but following rather the plan of Bergman,
as already noticed in fome notes; the fifth and
laft column is an analagous Englifh tranflation of
thefe terms.
   In  the former of thefe tables, the nomencla-
ture  recommended by  Dr  Black,   as  already
mentioned in fome former notes, is  adopted for
the alkaline and  earthy falifiable bafes.   In the
latter, the nomenclature ufed  by  the  French
chemifts for thefe fubftances, is retained in the
fecond  and third fections ;  but  the  propofed
alteration  is introduced in the fourth and fifth,
together with  a fimilar alteration, likewife for-
merly mentioned  in  fome   notes,   for  giving
names to  the  metallic  oxyds, to  diftinguifh
thefe  from  the   reguline or   perfectly  fimple
ftate, analagous to  alkalies.   To tranflate this
laft idea of nomenclature into Englifh,  required
fuch  a violent  change, that the ufual  numes  of
the metals in Englifli are reUm^d; that, however, 
          OF  CHEMISTRY.      563

can induce no ambiguity, and it muft be gene-
rally underftood, that  no metal  can  enter  into
combination with an acid, unlefs it be previoufly
oxydated.                                   J 
364
ELEMENTS
TABLE of  the Acids in the  order of
                     Affinity.
      I.
Nitrous, Nitric,
 Sulphurous,
 Sulphuric,Mu-
 riatic, and Se-
 bacic Acid.
II.
III.
Acetous,  Ace-
 tic, and For-iBoracic Acid.
 mic Acids.
Baryta.
Lixa.
Trona. .
Calca.
Magnefia.
Ammona.
Arga.
Oxyds of
  Zinc.
  Iron.
  Manganefe.
  Cobalt.
  Nickel.
  Lead.
  Tin.
  Copper.
  Bifmuth.
   Antimony.
  Arfenic.
   Mercury.
   Silver.
   Gold.
   Platina.
     IV.

Nitro-muriatic
    Acid.
Baryta.
Lixa.
Trona.
Calca.
Magnefia.
Ammona.
Oxyds of
  Zinc.
  Manganefe.
  Iron.
  Lead.
  Tin.
  Cobalt.
  Copper.
  Nickel.
  Arfenic.
  Bifmuth.
  Mercury.
  Antimony.
   Silver.
   Gold.
   Platina.
 Arga.
—"
Calca.
Baryta.
Magnefia.
Lixa.
Trena.
Ammona.
Oxyds of
  Zinc.
  Iron.
  Lead.
  Tin.
  Cobalt.
  Copper.
  Nickel.
  Mercury.
 Arga.
Arga.
Ammona.
Oxyds of
  Antimony.
  Silver.
  Arfenic.
Baryta.
Oxyd of
  Bifmuth.
Calca.
Oxyds of
  Cobalt.
   Copper.
   Tin.
   Iron.
 Magnefia.
 Oxyds of
   Manganefe.
   Mercury.
   Molybdena. |
   Nickel.
   Gold.
   Platina.
   Lead.
  Lixa.
  Trona.
  Oxyds of
   Tungftein.
   Zinc. 
OF  CHEMISTRY.      365
       V.
Phofphorous, Phof-
  phoric, Tungftic,
  Tartarous, Oxalic
  and Saccho-lactic
  A cids.
      VIII.
Fluoric and Arfeniac
      Acids.
Calca.
Baryta.
Magnefia.
Lixa.
Trona.
Ammona.
Oxyds asin Col. II.
Arga.
      XI.
Pyro-mucous Acid
 Lixa.
 Trona.
 Baryta.
 Calca.
 Magnefia.
 Ammona.
 Aiga.
 Oxyds as in Col. II
omitting filver, Gold
and Platina.
VI.
Carbonic Acid.
    IX.
Citric Acid.
 Baryta.
 Calca.
 Magnefia.
 Lixa.
 Trona.
 Ammona
 OxydsasinCol.il.
omitting Tin,  Nic-
kel, and Bifmuth.
  Arga._________
    XII.
Succinic Acid.
Baryta.
Calca.
Lixa.
Trona.
Ammona.
Magnefia.
Arga.
Oxyds as in Col. I.
VII.
Murioxic Acid.
      X.
Pyro-lignous Acid.
  Calca.
  Baryta.
  Lixa.
  Trona.
  Magnefia.
  Ammona.
.  OxydsasinCol.II.
:-  Arga.
   XIII.
Pruffic Acid.
   Lixa.
   Trona;
   Ammona.
   Calca.
   Baryta.
   Magnefia.
   Oxyds as in Col. I.
I. placing Silver before
  Mercury.
Calca. Baryta. Magnefia. Lixa, Trona. Ammona. Arga. Oxyds as in Col. I.	Baryta. Calca. Lixa. Trona. Magnefia. Ammona. Arga. . Oxyds as in Col. I.	Baryta. Lixa. Trona. Calca. Magnefia. Arga. Oxyds as inCol. I.
 
366
ELEMENTS
TABLE of the Nomenclature
Acids.	Lavoifier.	
	Latin.	Englifh.
Sulphurous.	Sulphis potaffse	Sulphite of potafh
	■■ fodae	-------of foda
Sulphuric.	■ ■ ammonias Sulphas calcis	-------of ammoniac Sulphat of lime
	„......mifmcfiT	
		
		-------of barytes
		
		
		
Phofphorous.	Phofphis potaffe	Phofphite of Potafh
Phofphoric.	Phofphas fodae	Phofphat of foda
Nitrous.	Nitris ammonias	Nitrite of ammoniac
Nitric.	Nitras argenti	Nitrat of filver
Oxygenated Ni-tric.	-----auri oxygenata	Oxygenated nitrat of gold
Muriatic.	Murias mercurii	Muriat of mercury
Oxygenated Muriatic.	----potafTse oxygenata	Oxygenated muriat of potafh
Boracic.	Boras foda:	Borat of foda
Acetous.	Acetis ammoniae	Acetite of ammoniac
Acetic, &c.	Acetas cupri, &c.	Acetat of copper, 8cc.
 
OF CHEMISTRY.     367
of the Neutral Salts.
Propofed	Alteration.
Latin.	Englifh.
Lixa fulphurofa	Sulphurous lixa
Trona fulphurofa Ammona fulphurofa	
	
	
Calca fulphurica	Sulphuric calca
Magnefia fulphurica	-----magnefia
Baryta fulphurica	----- baryta
Arga fulphurica	-----arga
Lixa phofphorofa	Phofphorous lixa
Trona phofphorica	Phofphoric trona
Ammona nitrofa	Nitrous ammona
Argenta nitrica	Nitric filver
Aura nitroxica	Nitroxic gold
Mercuria muriatica	Muriatic Mercury
Lixa murioxica	Murioxic lixa
Trona boracica	Boracic trona
Ammona acetofa	Acetous ammona
Cupra acetica, &c. 1	Acetic copper, &c.
 
 
OF  CHEMISTRY.       2h
             PART  III.


Defcription  of the  Inftruments  and
       Operations  of Chemiftry*
      INTRODUCTION.


   IN the two former parts of this work, I defign-
    edly avoided being particular in defcribing
the manual operations of chemiftry -, becaufe I
had found,  from experience, that, in a work ap-
propriated to reafoning, minute defcriptions of
proceffes and  of plates interrupt the chain of
ideas, and render the  neceffary attention  both
difficult and tedious  to the  reader.   On the
other  hand,  if I had confined myfelf to the
fummary defcriptions hitherto given, beginners
could  have only acquired very vague  concep-
tions of practical chemiftry from my work -, and
muft have  wanted  both confidence  and intereft
in operations which they could neither repeat nor
                  A  a 
370         ELEMENTS

thoroughly comprehend.  This want could not
have  been fupplied  from books ;  for, befides
that there are  not any which  defcribe the mo-
dern inftruments aad experiments fufficiently at
large, any work that could have been confulted,
would have prefented thefe things under a  very
different order of arrangement, and in  a  dif-
ferent chemical language; which muft greatly
tend to injure the main object of my perform-
ance.
   Influenced by  thefe motives, I determined to
referve, for a third part of my work, a fummary
defcription of all the inftruments and manipu-
lations relative to elementary chemiftry.   I con-
fider it as better placed at the end than  at the
beginning of the book;  becaufe,  otherwife, I
muft have been obliged to fuppofe the  reader
converfant with circumftances, which a beginner
cannot  know,  and to become  acquainted  with
which he  muft have previoufly read the elemen-
tary part.  The whole  of this third part may,
therefore,  be confidered as  refembling the  ex-
planations of places, which are ufually  placed
at the end of academic memoirs,  that they may
 not interrupt  the  connection of  the text, by
 lengthened defcription.
   Though I have taken great pains  to  render
 this  part clear and  methodical,  and have not
 omitted any effential  inftrument or  apparatus, 
       OF  CHEMISTRY.       37*

I am far from pretending by it to fet afide the
neceffity of attendance upon lectures  and labo*
ratories, for  fuch  as wi&  to acquire accurate
knowledge ofthe fcience of chemiftry.   Thefe
fhould familiarife themfelves to the employment
of apparatus, and to the performance of experi-
ments by actual experience.   Nihil efi in intel-
letlu quod non prius fuerit in fenfu,  the motto
 which the celebrated Rouelle caufed to be paint-
 ed in large characters on a confpicuous part of
 his laboratory, is  an important truth never to
 be loft fight of either by teachers or ftudents of
 chemiftry.
   Chemical operations may be naturally divided
 into  feveral clalTes,  according  to the purpofes  •
 they are intended  for performing.   Some  may
 be confidered as purely mechanical,  iuch as the
 determination ofthe weight and bulk of bodies,
 trituration, levigation, fearching or lifting, wafh-
 ing,  filtration, &c.  Others may be confidered
 as real chemical  operations; becaufe they are
 performed by  means of chemical powers and
 agents j fuch as folution, fufion, &c.  Some of
 thefe are intended for feparating the elements of
 bodies from each other; fome for reuniting thefe
  elements together j and fome, as combuftion, pro-
  duce both thefe effects during the fame procefs.
    Without rigoroufly  endeavouring to follow
  the above method, I mean to  give  a detail of 
372         ELEMENTS

the chemical operations  in  fuch  order  of ar-
rangement as  feems beft calculated for convey-
ing inftruction.   I fhall be more  particular  in
defcribing the apparatus connected with modern
chemiftry j  becaufe'thefe  are  hitherto  little
known by men,  who have devoted much  of
their time to chemiftry, and even by many pro-
feffors ofthe fcience.
CHAP. 
OF  CHEMISTRY.  .     373
               CHAP.   I.


 Of the Inftruments neceffary for determining the Ab-
   folute and Specific Gravities of Solid and Liquid
   Bodies.

      THE  beft method  hitherto known for de-
       termining the quantities of fubftances fub-
 mitted to chemical experiment, or refulting from
 them, is by means of accurately conftructed beams
 and fcales,  with properly  regulated  weights;
 which well-known operation  is called  weighing.
 The denomination  and quantity of the weight
 ufed as  an unit or ftandard for this purpofe,  are
 extremely arbitrary •, and vary, not only in diffe-
 rent kingdoms,  but even in different provinces
 of the fame  kingdom,  and in different cities of
 the fame province.   This variation is of infinite
 confequence to be well underftood in commerce
 and in the arts;  but,  in chemiftry, it is of no
 moment what particular denomination of weight
 be  employed,  provided  the refults of  experi-
ments  be expreffed  in  convenient fractions  of
the fame denomination.   For this purpofe,  un-
til all the weights ufed in focifty be reduced  to
the fame ftandard, it will be fufficient  for che- 
574
ELEMENTS
mills in different parts, to ufe the common pound
of their own country, as the  unit or ftandard,
and  to exprefs aH its fractional parts in decimals,
inftead  of the arbitrary  divifions now  in  ufe.
By this method the chemifts of all countries will
be thoroughly underftood by each other -, as, al-
though the  abfolute weights of the ingredients
and products cannot be known, they will readily,
and  without calculation, be able to determine the
relative proportions of thefe to each other with
the utmoft accuracy j fo that in  this way we fhall
be poffeffed of an univerfal language for this part
of chemiftry.
   "With this view I have long projected  to have
the  pound divided into decimal fractions ;  and I
have of late fucceeded, through the afiiftance of
Mr. Fourche,  balance-maker at  Paris, who has
executed it fonne with great  accuracy and judg-
ment.   I recommend to all who carry on experi-
ments to procure fimilar divifions of the pound,
which  they will find both eafy and fimple in its
application, with  a  very  fmall knowledge of
decimal fractions*.

   •  Mr. Lavoifier gives,  in this part  of his work,  very
accurate directions for  reducing  the common fubdivifions
of the French pound into decimal fractions, and vice 'verfa,
by means of tables, fubjoined to this  3d part.  As thefe
inftruftions, and the table, weuld be ufelefs  to the Britifh
Chemift, from the difference  between the fubdivifions of the 
       OF  CHEMISTRY.       375

   As  the ufefulnefs and accuracy of chemiftry
 depend entirely upon the  determination  of tjie
 weights  of the ingredients and  products,  both
 before and after experiments, too much preci-
 fion cannot be employed in this part ofthe fub-
ject ; and, for this purpofe, wc muft be provided
 with good inftruments.   As we are often obli-
 ged,  in  chemical proceffes,  to afcertain, within
 a grain  or lefs,  the tare or weight of large and
 heavy inftruments,  we muft have  beams made
 with peculiar  nicety   by accurate  workmen -,
 and thefe muft always  be  kept apart from  the
 laboratory, in  fome place where the vapours of
 acids, or  other  corrofive liquors,  cannot have
 accefs;  otherwife  the  fteel will  ruft,  and  the
 accuracy of the balance be deftroyed.  I have
 three fets,  of different fizes,  made by Mr. Fon-
tin  with the utmoft nicety; and, excepting thofe
made by Mr.  Ramfden of London, I do  not
think any  can compare with them for  precifion
and fenfibility.   The largeft of thefe  is about
three feet  long in  the  beam for large weights,
up to fifteen or twenty pounds.  The fecond, for
 weights  of eighteen or twenty ounces, is  exact

French and Troy pounds, I have omitted them ; but have
fubjoined, in the appendix, accurate rules for converting the
one  denomination  into  the other, together with tables for
reducing the  various divifions of our Troy pound into deci-
mals, and  for converting thefe decimals into the ordinary
divifions.—T. 
 376          ELEMENTS

 to a tenth  part of a grain; and the fmalleft, cal-
 culated only for weighing about one dram, is fen-
 fibly affected by the five hundredth part of a grain,
   Befides thefe nicer balances, which are  only
 ufed for experiments of refearch, we  muft  have
 others of lefs value,  for the ordinary purpofes of
 the laboratory.  A large iron  balance,  capable
 of weighing forty or fifty pounds,  within half a
 dram ; one of a middle fize, which may ascer-
 tain eight  or  ten pounds, within ten or twelve
 grains ;  and  a fmall  one,  by  which about  a
 pound may be determined within one grain.
  We muft likewife be provided with weights
 divided into their fevtral fractions, both  vulgar
 and decimal,  with the utmoft nicety, and  veri-
 fied by means of repeated and accurate trials in
 the niceft fcales: and it  requires  fome experi-
ence,  and  to  be  accurately acquainted with the
different weights, to be able  to ufe  them  pro-
perly.   The beft way of  precifely  afcertaining
 the weight of any particular fubftance, is to weigh
it twice, once with the decimal divifions ofthe
pound, and another time with  the common  fub-
divifions or vulgar fractions ; and, by comparing
thefe,  we attain the utmoft accuracy.
  By the  fpecific gravity  of any fubftance  is
underftood  the quotient of its abfolute  weight
divided by its  magnitude,  or,  what is the fame,
the  weight  of  a determinate bulk of any body. 
OF  CHEMISTRY.
377
  The weight of a determinate magnitude of water
  has been generally affumed as unity for this pur-
  pofe i and we exprefs the fpecific gravity of gold,
  fulphuric acid, &c. by faying, that gold is nine-
  teen times i and fulphuric acid twice the weight
  of water; and fo of other bodies.
    It is the more convenient to affume  water as
  unity in fpecific gravities, that thofe  fubftances,
  whofe fpecific gravity we wifh to determine, are
  moft commonly weighed in  water for that pur-
  pofe.   Thus, if we  wifh to determine the fpe-
  cific  gravity of gold flattened under the ham-
  mer, and fuppofing the piece of gold  to weigh
  48989t£™«  in the air*,  it is fufpended by means
  of  a  fine metallic wire under the fcale of a hy-
 droftatic balance, fo  as to be  entirely immerfed
 in  water, and  again weighed.   The  piece of
 gold in Mr. Briffon's experiment, loft by this
 means  253 grs.; and, as  it  is evident that the
 weight loft by  a body weighed in water is pre-
 cifely equal to the weight ofthe water difplaced,
 or  to that of an equal volume  of  water, we
 may conclude,  that,  in equal magnitudes, gold
 weighs 4898^. grs.  and water 253 grs. which,
 reduced  to unity, gives  1.0000  as  the fpeci-
 fic  gravity of water, and 19.3617 for that of
 gold.  We may operate in  the  fame manner
with all folid  fubftances.  We have, however,
  *  Vide Mr. Briffon's Effay upon  Specific Gravity,  p. 5.
—A.                    Bbb 
37*
ELEMENTS
rarely any occafion, in chemiftry,  to determine
the fpecific gravity of folid bodies, unlefs when
operating upon alloys or metallic  glaffes;  but
we have very frequent neceffity to afcertain  that
of fluids, as it is often the only  means of judg-
ing of their purity or  degree of concentration.
   This object may be very fully accompliflied,
with the  hydroftatic balance, by weighing a fo-
lid body, fuch,  for  example,  as  a little ball of
rock cryftal, fufpended by a very fine gold wire,
firft in  the  air,  and  afterwards  in  the  fluid
whofe fpecific gravity we wifh to difcover.  The
weight loft by the cryftal, when weighed in the
liquor, is  equal to that of an equal bulk of the
liquid.   By  repeating this operation fuceffively
in water and different fluids, we can very readily
afcertain, by a  fimple and eafy calculation,  the
relative fpecific gravities of thefe  fluids, either
with refpect  to  each other or to water.   This
method is not,  however,  fufficiently exact, or,
at leaft,  is  rather  troublefome,   from its  ex-
treme delicacy,  when  ufed for liquids differing
but little  in fpecific gravity from water j fuch,
for inftance,  as  mineral waters,   or any  other
 water containing  very fmall portions of fait in
folution.
   In  fome  operations  of this nature,  which
 have not hitherto been  made public, I employed
an inftrument of great  fenfibility for this  pur- 
OF  CHEMISTRY.
379
 pofe with great advantage.  It confifts of a hol-
 low cylinder, Ab c f, PI. vii. fig. 6. of brafs, or
 rather of filver, loaded at its bottom,  b cf, with
 tin,  as reprefented fwimming in a jug of water,
 I m n  o.  To the upper part of the cylinder is
 attached a (talk of filver wire, not more than
 three-fourths of a line in diameter, furmounted
 by a little cup d, intended for containing weights;
 upon the ftalk a mark is made  at g, the ufe of
 which  we fhall prefently explain.   This  cylin^
 der may be made of any flze ; but, to be accu-
 rate,  ought  at leaft to difplace four pounds of
 water.  The weight of tin with which  this in-
 ftrument is loaded, ought to be fuch as will make
 it  remain   almoft  in equilibrium in diftilled
 water;  and  fhould not require  more  than half
 a  dram, or  a dram  at  moft,  to make it fink
 tog.
   We muft  firft  determine,  with  great  preci-
 fion,  the  exact weight of the  inftrument, and
 the number  of additional grains  requifite  for
 making it fink, in diftilled water of a determi-
 nate temperature, to the mark.  We then per-
 form  the fame experiment upon all the  fluids
 of which we wifh to afcertain the fpecific  gravi-
 ties ;  and by means of calculation, reduce the
 obferved differences  to  a common ftandard of
 cubic  feet, pints, or pounds, or of decimal frac-
tions,  comparing  them with water,  This me- 
38o
ELEMEN TS
thod, joined  to  experiments  with  certain re-
agents*, is  one of the beft  for determining the
quality  of waters, and is even capable  of point-
ing out differences which efcape the moft accu-
rate chemical analyfis.  I fhall, at  fome future
period,  give an account of a very extenfive fet
of  experiments  which I  have  made  upon this
fubject.
  Thefe  metallic  hydrometers  arc only to be
ufed for determining the fpecific  gravities  of
fuch waters as  contain only neutral falts or al-
kaline fubftances ; and they may be conftructed
with different degrees  of ballaft for alkohol and
other fpiritous liquors.   When the fpecific gra-
vities of acid liquors are  to be afcertained, we
muft ufe a glafs  hydrometer,   as  reprefented
PI.  vii. fig. I4f.  This  confifts of a hollow cy-
linder of glafs, a b cf, hermetically fealed at its
lower end,  and drawn  out  at the  upper extre-
mity,  into  a capillary tube a, ending in the little
cup or bafon d.   This  inftrument is ballafted
with more  or lefs mercury,  at the bottom of the
cylinder, introduced through the tube,  in  pro-

   * For the  ufe of thefe reagents fee Bergman's excellent
 treatife upon the analyfis of mineral waters, in  his Chemical
 and Phyfical Effays.—T.
   f Some years ago, that is,  before  1787, I  have feen fi-
 milar glafs hydrometers, made for Dr. Black by E. Kn e, a
 very ingenious Artift of this city.—T. 
       OF  CHEMISTRY.       381

portion to the weight of the liquor intended to
be examined.  We may introduce a fmall gradu-
ated flip of paper into the tube a d; and, though
thefe degrees  do not exactly correfpond to the
fractions of grains in the different  liquors,  they
may be rendered very ufeful in calculation.
  What is faid in this chapter may fuffice, with-
out farther enlargement, for indicating the means
of afcertaining the abfolute and fpecific gravities
of folids and fluids,  as  the neceffary inftruments
are generally known, and may eafily be procu-
red.  But, as  the  inftruments I have ufed for
meafuring the gaffes are not any where defcribed,
I fhall give a more detailed account of thefe in
the following chapter.
CHAP. 
38s           ELEMENTS
CHAP   II.
Of Gazometry, or the Meafurement of the Weight
       and Volume of Aeriform Subftances.
                SECT.   I.

 Defcription of the Pneumato-chemical Apparatus.

     THE  French chemifts have of late applied
      the name of pneumato-chemical apparatus
to the  very fimple  and ingenious contrivance,
invented by Dr. Prieftly, which is now indifpen-
fibly neceffary to every laboratory.  This con-
fifts of a wooden trough,  of larger or fmaller
dimenfions, as is thought convenient, lined with
plate-lead or tinned copper, as reprefented  in
perfpective, PI. V.—In Fig. i. the  fame trough
or ciftern is fuppofed to have two of its fides cut
away, to fhew its interior construction  more di-
ftindtly.  In this apparatus, we diftinguifh be-
tween  the  fhelf ABCD Fig. I. and 2. and  the
bottom or  body of  the ciftern FGHI Fig. 2. 
OF  CHEMISTRY       383
 The jars or bell-glaffes are filled with water in this
 deep part,  and, being turned with their mouth s
 downwards,  are afterwards fet upon the fhelf
 ABCD, as fhewn Plate X. Fig. 1. F.—The up-
 per parts of the fides of the ciftern,  above the
 level ofthe fhelf, are called the rim or borders.
    The ciftern ought to be filled with water, fo
 as to ftand at leaft  an inch and a half deep over
 the fhelf;  and it fhould  be of fuch dimenfions
 as to admit of at leaft one foot of water in every
 direction in the well, or ciftern.  The fize above
 defcribed is fufficient for ordinary occafions;  but
 it is often convenient, and  even neceffary, to
 have more  room.   I would therefore advife fuch
 as intend to employ themfelves ufefully  in che-
 mical experiments,  to have this apparatus made
 of confiderable magnitude, where their place of
 operating will allow. The well of my principal
 ciftern holds  four cubical feet  of water, and its
 fhelf has a furface of fourteen fquare feet: yet,
 in fpite of this fize,  which I at firft thought irn-
. moderate,  I am often ftraitened for room.
    In laboratories, where a confiderable number
 of experiments are performed, it is neceffary to
 have feveral leffer cifterns, befides the large one
 which  may be called the general magazine ;  and
 even fome portable ones, which may be moved
 when  neceffary, near a  furnace,  or  wherever
 they may be wanted.  There are likewife fome 
3*4          ELEMENTS

•petitions which dirty the water ofthe appara-
tus, and therefore require to be carried on in cif-
terns by themfelves.
  It were doubtlefs confiderably cheaper to ufe
cifterns of wood,  fimply dove-tailed, or  iron-
bound tubs,  inftead of being lined with  lead or
copper; and in my firft experiments I ufed the  n
made in that way; but I foon difcovered their
inconvenience.  If  the water be not  always
kept at the fame level, fuch of the dovetails as
are left dry, fhrink,  and,  when more water  is
added, it efcapes through the joints, and runs out.
  We employ cryftal jars or  bell glaffes, PI. V.
Fig- 9. A. for containing the gaffes in this ap-
paratus.  And, for tranfporting thefe, when full
of gas, from one ciftern to another, or for keep-
ing them in referve,  when the ciftern  is too full,
we  make ufe of a flat difh BC, furrounded by a
ftanding up rim or border, with two handles DE
for carrying it by.
  After feveral  trials of different materials,  I
have  found  marble the beft fubftance for  con-?  .
ftructing the mercurial pneumato-chemical ap-
paratus ;  as it is perfectly impenetrable by mer-
cury, and is not liable, like wood, to feparate at
the junctures, or to allow the mercury to efcape
through chinks; neither  does it run the  rifk  of
breaking, like glafs,  ftone-ware,  or  porcelain.
Take a block of marble BCDE, Plate V. Fig. 3. 
OF  CHEMISTRY.       385
  and 4. about  two feet long,  15  or  18 inches
  broad,  and ten inches thick, and  caufe it to be
  hollowed out, as at m n, Fig. 5.  about four inches
  deep, as a refervoir for the mercury;  and, to be
  able more conveniently  to fill the jars, cut the
  gutter T V, Fig.  3. 4. and 5. at leaft four inches
  deeper; and as this trench may  fometimes prove
  troublefome, it is made capable of being covered
  at pleafure by  thin boards,  which flip into the
  grooves x y,  Fig. 5.  I have two marble citterns
  upon this  construction,  of different fizes, by
  which I can always employ one  of them as a re-
 fervoir of mercury, which it preferves with more
 fafety than any other veffel, being neither fubject to
 overturn, nor to any other accident.  We operate
 with mercury in this apparatus exactly as with
 water in the one before defcribed ;  but the bell-
 glaffes  muft be  of fmaller diameters, and much
 ftronger; or we may ufe glafs tubes,  having their
 mouths widened, as in Fig. 7. ; thefe arc  called
 eudiometers, by the glafs-men who fell them. One
 ofthe bell-glaffes is reprefented Fig. 5. A.  ftand-
 ing in its place; and what is called a jar is engra-
 ved at Fig.  6.
  The mercurial pneumato- chemical apparatus is
 neceffary in all experiments wherein the difengaged
 gaffes are capable of being abforbed by water; as is
 frequently the cafe, efpecially in all combinations,-
excepting thofe of metals,  in fermentation, &c.
                    C c c 
3§5         £ L £ M E M T §


               SECT.  II.

              Of the Gazometer.

  I give the  name  of gazometer to ah inftru-
ment  which I invented, and caufed to be  con-
ducted, for the purpofe  of a  kind of bellows,
which might furnifh an uniform and continued
ftream of oxygen gas in  experiments of fufion.
Mr Meufnier and I have fince made very confider-
able corrections and additions,  having converted
it into what may be called an univerfal instrument,
without which it is hardly poffible to perform
moft ofthe very exact experiments.  The name
we have given the inftrument indicates its intenti-
on for meafuring the volume or quantity of gas
fubmitted to it for examination.
   It confifts of a ftrong iron  beam,  DE, PI.
VIII.  Fig.  i,  three feet  long,  having at each
end, D,  and E, afegmentofa circle,  likewife
ftrongly contracted  of iron,  and very firmly
joined. Inftead of being poifed  as in ordinary ba-
lances, this beam refts, by means of a cylindri-
cal axis of  polifhed fteel,  F, Fig. 9. upon two
large moveable brafs friction-wheels, by which
the refiftance to its motion from friction is confi-
derably diminifhed, being converted into friction
of the fecond  order.  As an additional preeau- 
        OF  CHEMISTRY.      #7

tion,  the  parts  of thefe wheels which fupport
the axis ofthe beam are covered with plates of
policed rock-cryftal. The whole of this machi-,
nery is .fixed to the top  of the folid column of
wood BC, Fig. 1.   To one extremity D of the
beam, a fcale P, .for holding weights, is fufpend.-
ed by a flat chain, which applies to the curvature
of the arc uTk,  in a groove made for the pur-
pofe.  To the other extremity E ,of the beam is
applied another  flat chain, / k tn, fo conftrudbeo',
as to be incapable of lengthening or iho.rtening,
by being lefs or more charged wjth we,ight.  To
this cha,in, an  iron trivet,  with three branches,
at, ci,  and fy, is ftrongly fixed at / / and thefe
branches fupport a large inverted jar A, of ham-
mered copper, about 1* inches diameter,  jtrtf
■%q inches deep.   The whole of this machine j§
reprefented in perspective, PI.  VIII. Fig. 1 : anjl
PI. IX.  Fig.  2. aqd 4. give perpendicular fac-
tions, which fhew its interior ftructure.
  iRowndijhe bottom (of the jar, on its outfide,
is fixed, PI. IX. pig. 2. a border  divided into
compartments 1, 2, 3,  ,4, ,&c. intended' to re-
ceive leaden weights  feparately reprefepted  1,
2> 3> F'g-  3-  Thefe are  intended fqr jncreafing
the weight of the jar, when ^confiderable pref-
fure is  requifite, as will be afterwards explain-
ed, though fuch .neeeffity fcldom occurs.   The
cylindrical jar A is entirely open below,  de, PI.
IX. Fig. 4.;  but js clofed .above, with jx copper 
3S8          ELEMENTS
lid a b c, open at b f, and capable of being fhut
by the cock g.   This lid,  as may be fcen by in-
fpecting the figures, is placed a few inches within
the top of the jar, to prevent the jar from being
ever entirely immerfcd in the water, and covered
over.  Were I to have this inftrument made over
again, I fhould  caufe the lid to  be confiderably
more flattened,  fo as to be almoft level.  This
jar or refervoir of air is contained in the cylin-
drical copper veffel LMNO, PI. VIII. Fig. i.
filled with water.
   In the middle of the cylindrical veffel LMNO,
PI. IX.  Fig. 4. are placed  two  tubes  st,  xy,
which are made to approach each other at their
upper extremities ty.   Thefe are made of fuch a
length as to rife  a little above the  upper edge
LM ofthe veffel LMNO: and when the jar abcde
touches the  bottom NO,  their upper ends enter
about half an inch into the conical hollow b, lead-
ing to the ftop-cockg.
   The bottom ofthe veffel LMNO is reprefent-
ed PI. IX.  Fig. 3.  in the middle  of which a
fmall hollow hemifpherical cap is foldered, which
may be confidered as the broad end of a funnel
reverfed; the  two tubes st, xy,  Fig. 4. are ad-
apted to this cap at s and x, and by this means
communicate with the tubes mm, nn, 00, pp, Fig.
3. which are fixed horizontally upon the bottom
ofthe veffel, and all of which  terminate in, and
are united by, the fpherical cap sx.  Th*ee  of 
         OF  CHEMISTRY,       389

  thefe tubes are continued out of the veffel, as in
  PI. VIII. Fig. 1.  The firft marked in that figure
  i> 2, 3, is  inferted at  its extremity 3, by  means
  of an intermediate  flop-cock 4, to the jar V.
  which ftands upon the fhelf of a fmall pneumato-
  chemical apparatus  GHIK, the  infide of which
  is fhewn PI. IX. Fig.  1.  The fecond tube is ap-
  plied againft the outfide ofthe veffel LMNO from
  6 to 7 ; is continued at 8, 9, 10; and at 11  is en-
  gaged  below the jar V.   The former of  thefe
  tubes is intended  for conveying gas  into the:
  machine,  and  the  latter for conducting  fmall
  quantities for trials under jars.  The gas is made
  either to flow into ar out ofthe machine, accord-
  ing to the   degree of preffure it receives; and
  this preffure is varied at pleafure, by loading the
 fcale P lefs or more, by means of weights.  When
 gas is to  be introduced into the machine, the pref-
 fure is taken off, or even rendered negative; but
 when gas is to be expelled,  a preffure  is  made
 with fuch degree of force as is found neceffary.
   The third tube 12, 13, 14, 15, is intended for
 conveying air or gas to any  neceffary place or
 apparatus for combuftions, combinations, or any
 other experiment in which it may be required.
   To explain the ufe ofthe fourth tube/ I  muft
 enter into fome  difcuffions.   Suppofe the veffel
 LMNO, PI. VIII. Fig. 1. full of water,  and the
jar A  partly filled with gas, and  partly with
 water; it is   evident that the  weights  in the ba-' 
3^>
ELEMENTS
fon P may be fb adjufted,  as to-ocea$$fl an ex-
act equilibrium between the weight «f the bafon
and ofthe jar,fo that the external air fhall not tend
to enter into the jar, nor the gas to efcape from  it:
and in this cafe, the water will ftand exactly at
the fame level, both within and without the jar.
On the contrary, if  the weight io the bafon P
be diminiftied, the jar will  thenprefs downwards
from  its own gravity, and the water will ftand
lower within  the jar than it does without: in this
cafe, the included  air or gas will fuffer a degree
of comprefiion above that experienced by the ex-
ternal  air, exactly proportioned to the weight of
a column of water, equal to the difference ofthe
external and internal furfaces ofthe water.
  tFrom thefe reflections, Mr Meufnier contrived
a method of determining the exact degree of pref-
fure to which the gas contained in  the jar is at
any time expofed.  For this purpofe, he employs
a-double glafs fyphon, 19,  20, 21, 22, 23, firmly
cemented at  19 and 23.   The extremity  19 of
this fyphon communicates freely with the  water
in  the external veffel of the  machine:  and  the
extremity  23  communicates with  the  fourth
tube, at the bottom of the  cylindrical veffel;  and
confequently  by means  of  the perpendicular
tube st, PI. IX. Fig. 4. with the  air contained in
the jar.   He likewife cements, at 16, PI. VIII.
Fig.  1.-another glafs tube, 16,  17, 18,  which 
OF  CHEMISTRY.
39*
  communicates at 16 with the water in the exte-
  rior veffel LMNOi and,  at its upper end 18, is
  open to the external air.
    By  thefe feveral Contrivances,  it is  evident,
  that the water muft ftand in the tube 16, 17,  18,
  at the fame level With that in the Cifterri LMNO;
  ahd, on the contrary,  that,  in the branch  1^,
  20,  21, it muft ftand higher or lower acedrdteg
  as the  air in the jar is  fubjected to a greater of
  leffer preffure  than  the external air.   To afcer-
  tain thefe differences, a brafs fcale, divided irito
  inches  and lines,   is fixed  betweert  thefe two
 tubes,   it is readily conceived, that,  as air, and
 all other elaftic fluids, niirft increafe  in  Weight
 by  compreffion, it is  neceffary  to know their
 degree  of condenfation, to be enabled to calcu-
 late their quantities, and to convert the meafure
 of their volumes into correfpondent  weights:
 and this objeft is intended to be  fulfilled by the
 contrivance now defcribed.
   But, to determine the fpecific gravity of air,  or
 of gaffes, and to afcertain their weight in a known
 volume, it is neceffary to know their  tempera-
 ture, as well as  the degree of preffure  under
 Which they fubfift:  and this is accomplished by
 means of a fmall thermometer, ftrortgly Cement-
 ed into a brafs collet, which fcrews  into  the lid
of the jar A.  This thermometer is reprefented
feparately, PI. VIII. Fig.  10. and  in  its place
24, 2$> Fig. 1.  ahd Pi. IX.  Fig. 4.  The bulb  is 
39*
ELEMENTS
 in the infide ofthe jar A, and its graduated ftalk
 rifes on the outfide of the lid.
  The practice of gazometry would ftill  have
 laboured under great difficulties, without farther
 precautions than  thofe above defcribed.  When
 the  jar  A  finks  in  the water of  the  ciftern
 LMNO, it  muft lofe a weight equal  to that of
 the  water which  it difplaces; and confequently
 the compreflion which it makes upon the  con-
 tained air or gas  muft  be proportionally dimi-
 nifhed.  Hence the gas furnifhed, during experi-
 ments, from the machine, will not have the fame
 denfity towards the end, which it had at the begin-
 ing, as its fpecific gravity is  continually  dimi-
 nifhing.   This difference may, it is true,  be de-
 termined by calculation: but  this would have
 occafioned fuch mathematical  inveftigations, as
 muft have rendered  the ufe  of this apparatus
 both troublefome and  difficult.   Mr  Meufnier
 has remedied this inconvenience, by the follow-
 ing  contrivance.   A  fquare  rod  of iron,  26,
 27, PI. VIII. Fig. 1.  is raifed perpendicular to
 the middle of the beam DE.   This rod paffes
 through  a hollow box of brafs 28,  which  opens,
 and may be  filled with lead:  and this box is
 made  to Aide  along the  rod,  by means  of  a
 toothed pinion playing in a rack, fo as to raife or
 lower the box,  and to fix it at  fuch  places as is
judged proper.
   When the lever or beam DE ftands horizon- 
OF CHEMISTRY.
393
  tal, this  box gravitates to neither fide.'  But,
  when  the jar A  finks into the ciftern LMNO,
  fo  as to make the beam incline to that fide, it is
  evident the loaded  box 28,  which then paffes
  beyond the  centre  of fufpenfion, muft  gravi-
  tate to the  fide  of the  jar,  and augment its
  preffure upon the  included  air.  This  is  in-
  creafed in proportion as the  box is  raifed to-
  wards  27;  becaufe   the fame weight exerts a
  greater power in  proportion  to the  length of
  the lever by which it acts.  Hence, by moving
  the box 28 along the rod 26,  27, we  can aug-
 ment or diminifli  the correction it is  intended
 to make upon the preffure of the jar :  and both
 experience and  calculation fhew,  that this may
 be made to compenfate very exactly for the  lofs
 of weight in the jar at all degrees of preffure.
   I have  not  hitherto explained the moft im-
 portant part of the ufe of this  machine,  which
 is the manner of employing it  for  afcertaining
 the quantities of the air or gas furnifhed during
 experiments.   To determine this with  the moft
 rigorous precifion,  and  likewife  the  quantity
 fupplied to the machine from  experiments,  we
 fix to the  arc  which terminates the  arm   of
 the beam E, PI. VIII. Fig.  1.  the brafs  fector
lm,  divided  into  degrees  and  half  degrees,
which confequently moves  in  common  with the
beam:  and the  lowering of  this  end of the
                   Ddd 
394           ELEMENTS

beam is meafured by  the fixed index 29, ^o,
which has a Nonius giving hundredth parts of a
degree, at its extremity 30.
  The whole particulars  of the different  parts
of the above defcribed machine, are reprefented
in Plate VIII. as follow.
  Fig. 2.  Is the flat chain invented  by Mr Vau-
canfon, and employed  for fufpending the fcale
Or bafon P, Fig.  1.  But,  as  this lengthens  or
fhortens according as it is more or lefs loaded, it
would not have anfwered for fufpending the jar
A, Fig. 1.
  Fig. 5.  Is  the chain  ikm, which  in  Fig.
I. fuftains the jar A.  This  is entirely  form-
ed of plates,  of polifhed iron, interlaced into
each  other, and held  together by  iron  pins.
This  chain does  not lengthen  in  any fenfible
degree, by any weight it is capable of fupporting.
  Fig 6.   The trivet, or three-branched ft'irrup,
by which the jar A is hung to  the balance, with
the fcrew by which it  is  fixed  in an accurately
vertical pofition.
  Fig. 3.  The iron rod  26, 27, which is fixed
perpendicular to the centre of the beam, with its
box 28.
  Fig. 7.  & 8.   The  friction-wheels, with the
piates of rock-cryftal Z, as points of contact by
which the friction ofthe axes  ofthe lever ofthe
balance is avoided. 
OF  CHEMISTRY.
39S
   Fig. 4. The piece of metal which fupports the
 axis of the friction-wheels.
   Fig. 9. The middle ofthe lever or beam, with
 the axis upon which it moves.
   Fig. 10. The thermometer for determining th«
 temperature ofthe air or gas contained in the jar.
   When this gazometer is to be ufed, the ciftern
 or external veffel, LMNO, PI.  VIII.  Fig.  1. is
 to be filled  with water to a determinate height,
 which fhould be the  fame  in all  experiments.
 The level ofthe water fhould be taken when the
 beam of the  balance ftands horizontal.  This le-
 vel, when the jar is at the bottom  of the ciftern,
 is increafed by all the  water which it difplaces,
 and is diminifhed in  proportion as the jar riles to
 its higheft elevation.   We next endeavour,  by
 repeated  trials, to difcover  at what elevation the
 box 28 muft be fixed, to render the preffure equal
 in all fituations ofthe beam.   I fhould have faid
 nearly, becaufe this correction is not  abfolutely
 rigorous: and differences of a quarter, or even of
 half a line, are  not of  any confequence.   This
 height  of the box 28 is  not the fame.for every
 degree  of preffure ;  but varies according as this
 is  of one, two, three, or more inches.  All  thefe
 fhould be regiftered with great order and precifion.
   We  next take  a  bottle which  holds  eight or
 ten pints, the  capacity of which  is very accu-
rately determined  by  weighing the water it is 
396           ELEMENTS

capable of containing.  This  bottle is turned
bottom upwards, full of water in the  ciftern of
the pneumato-chemical apparatus GHIK, Fig. i.
and is fet on its  mouth upon the  fhelf of the
apparatus, inftead of the glafs jar V, having the
extremity n ofthe  tube 7,  8, 9, 10, 11, m-
ferted into its mouth.  The machine is fixed  at
zero of preffure ; and the degree marked by the
index 30 upon the  fector m I is accurately ob-
ferved.  Then, by opening the ftop-cock 8, and
 prefling a little upon the jar A,  as much air is
 forced into the bottle as  fills  it entirely.  The
 degree marked by the index upon the fector is
 now obferved; and  we calculate what number
 of cubical inches correfpond to  each  degree.
 We  then fill  a fecond and third bottle, and fo
 on,  in the fame manner,  with  the fame precau-
 tions, and even repeat   the operation  feveral
 times with bottles of different fizes,  till  at laft,
 by  accurate   attention, we afcertain the exact
  gage or capacity of the jar A, in all its parts.
  But it is better to  have  it formed at firft accu-
  rately cylindrical;  by which we avoid thefe  cal-
  culations and eftimates.
    The  inftrument I  have been  defcribing was
   conftructed  with great accuracy and uncommon
   (kill by Mr Meignie junior, engineer and phyfi-
   cal inftrument-maker .   It is a moft valuable in-
   strument, from the great number of purpofes to 
OF  CHEMISTRY.
397
 which it is applicable ; and, indeed, there  are
 many  experiments  which are almoft impoffible
 to  be performed  without it.   It  becomes  ex-
 penfive, becaufe, in many experiments, fuch as
 the  formation of water and of nitric acid, it is
 abfolutely neceffary to  employ two of the fame
 machines.  In the prefent advanced ftate of che-
 miftry, very expenfive and complicated inftru-
 ments are become indifpenfably neceffary, for af-        '
 certaining  the  analyfis and fynthefis of bodies,
 with the requifite precifion as to quantity and pro-
 portion.  It is  certainly proper to endeavour to
 fimplify thefe,  and to  render  them lefs coftly ;
 but this ought by no means to be attempted  at
 the expence of their conveniency of application,
 and much lefs of their accuracy.

              SECT.   III.

 Some other  Methods  of meafuring the Volume of
                    Gaffes.

  The  gazometer  defcribed in the foregoing
 fection is too coftly  and too complicated for be-
 ing generally ufed in laboratories for meafuring
 the gaffes,  and is  not  even applicable to every
 circumftance of this kind.  In  numerous feries
of experiments,  more  fimple and  more readily
applicable methods muft be employed.  For this 
393          ELEMENTS

purpofe, I fhall defcribe the means I ufed before
I was in poffeflion of a gazometer, and which I
ftill ufe in preference to it, in the ordinary courfe
of my experiments.
  Suppofe that, after an experiment, there is a
refiduum of gas, neither abforbable by alkali nor
water,  contained  in  the upper  part of the jar
AEF, PI. IV. Fig. 3. Handing on the fhelf of a
pneumato-chemical apparatus, of which we wifh
to afcertain the quantity ; we muft firft  mark the
height to which  the mercury or  water rifes in
the jar with great exactnefs, by means of flips
of paper pafted in feveral parts round  the jar.
If we have been operating in mercury, we be-
gin by difplacing the mercury from the jar,  by
introducing water in its ftead.  This is  readily
done by filling a bottle quite full of water ; ha-
ving flopped it with your finger, turn it up, and
introduce its  mouth  below the edge of the jar ;
then, turning down its body  again,  the  mer-
cury, by its gravity, falls  into the  bottle, and
the  water rifes in  the  jar, and takes the place
occupied by the mercury.   When  this  is ac-
compliihed,  pour fo much  water into the cif-
tern ABCD  as will ftand about an inch over the
furface  ofthe mercury; then pafs the  difh BC,
PL V. Fig.  9. under the jar, and carry it to the
water  ciftern,  Fig. 1.  and 2.  We  here ex-
change the gas  into  another  jar,  which has 
OF CHEMISTRY.
399
 been previoufly graduated  in  the manner to be
 afterwards defcribed :  and we thus judge ofthe
 quantity  or volume of the  gas by means of the
 degrees which it occupies in the graduated jar.
   There  is another method of- determining the
 volume of gas,  which  may either  be fubftituted
 in place of the  one above defcribed, or may be
 ufefully employed as a correction  or  proof of
 that  method.   After the air or gas is exchanged
 from the  firft jar, marked with flips of paper,
 into  the  graduated jar, turn up  the mouth of
 the marked jar, and fill it  with water exactly to
 the marks EF, PI. IV. Fig. 3. and by weighing
 the water, the volume of  the air or gas it con-
 tained may be determined ; allowing one cubical
 foot or 1728 cubical inches, French meafure, for
 each 70 lbs. French weight, or the fame cubical
 volume, in Englifh meafure, for each 75.84 lbs.
 Englifh Troy,  of the water.
   The  manner  of graduating jars fof this pur-
 pofe is very eafy;  and we ought to be provided
 with feveral of different fizes, and even feveral
 of each fize,  in cafe of accidents.   Take a tall,
 narrow, and ftrong glafs jar, and,  having filled
 it  with water in the ciftern,  PI. V.  Fig. 1. place
 it upon the fhelf ABCD. We ought always to ufe
 the fame place for this operation, that the level
of the  fhelf may be always exactly fimilar,  by
which almoft the only  error to which this pro- 
400
E LEMENTS
cefs is liable will be avoided.   Then take a nar-
row mouthed phial holding exactly 5 oz. 2 drams,
12  grs. of water,  which correfponds to 10  cu-
bical  inches.  If you  have not one exactly of
this dimenfion, choofe  one a little larger,   and
diminifh its capacity to the  fize requifite,  by
dropping in a little melted wax and rofin.  This
fmall  phial ferves the purpofe  of a ftandard  for
gaging  the jars.   Make the air contained in this
bottle pafs into  the jar, and mark exactly the
place to which the water has  defcended.  Add
anothe» meafure of air, and again mark the place
of  the  water, andfo  on, till all the  water.be
difplaced.  It is of great confequence, that,  du-
ring the courfe of this operation, the bottle and
jar  be kept at the fame  temperature with the  wa-
ter  in  the ciftern :  and,  for this reafon, we muft
refrain, as  much  as poffible,  from keeping the
hands upon either, or,  if we fufpcct they have
been heated,  we muft cool them again by means
of  the water in the  ciftern.  The height of the
barometer  and thermometer during this experi-
ment  is of no confequence.
  When the marks have been thus afcertained
upon  the  jar  for  every ten cubical inches, we
engrave a fcale upon one of its fides, by means
of a diamond pencil.   Glafs tubes are graduated
in the fame manner, for ufing in the mercurial
apparatus,, only.  they  muft  be  divided   inrc 
OF  CHEMISTRY.
401
cubical inches, and  tenths of  a  cubical  inch.
The bottle ufed for gaging thefe muft hold 7 oz.
 1 dr. 1$ grs.  of mercury, which exactly corref-
pond to a cubical inch of that metal.
   This method of determining the volume of air
or gas,  by means of a graduated  jar,  has the ad-
vantage of not requiring any correction for the
difference of the height  between the furface of
the water within the jar, and  in the  ciftern ;
but  it  requires corrections  with refpect to the
height ofthe barometer and thermometer.   But
when we afcertain the volume of air by weigh-
ing the water which the jar is  capable of con-
taining, up  to the marks EF, it is neceffary to
make a farther correction, for the difference be-
tween the  furface of the water in  the ciftern,
and the height to which  it rifes  within  the  jar.
This will be explained in the fifth fection of this
chapter.

               SECT.  IV.

Of the Method of feparating the different Gaffes
              from each other.

  As experiments often produce two, three,  or
more fpecies of gas, it is neceffary to be able to
feparate thefe  from each other,  that  we may af-
certain the quantity and fpecies of each.  Sup-
                   E e e 
402
ELEMENTS
pofe that under the jar  A, PI.  IV. Fig. 3. is
contained a quantity of different gaflfes mixed
together, and ftandingover mercury.  We begin
by marking with flips of paper, as before direc-
ted,  the height at which  the mercury  ftands
within the glafs; and then introduce about a cu-
bical inch of water into the jar, which will fwim
over the furface ofthe mercury.   If the mixture
of gas contains any muriatic or fulphurous  acid
gas, a  rapid  and confiderable abforption will
inftantly take  place, from  the ftrong tendency
thefe  two gaffes have,  efpecially the former,  to
combine with, or be abforbed by water.  If the
water only produces a flight  abforption of gas,
hardly equal to its own bulk,   we  conclude,  that
the mixture neither contains muriatic acid,  ful-
phuric acid, or ammoniacal gas, but that it con-
tains carbonic acid gas, of which water only ab-
forbs  about its own bulk.   To  afcertain this
conjecture, introduce fome folution  of  cauftic
alkali, and the  carbonic acid gas will  be  gra-
dually abforbed  in the  courfe of a few hours.
It combines with  the  cauftic  alkali or potafh :
and the remaining gas is left almoft perfectly free
from  any fenfible refiduum of carbonic acid gas.
   After each experiment of this kind, we muft
carefully mark the height at which the mercury
Hands within  the  jar, by  flips of paper pafted
on, and varnifhed over when dry, that they may 
OF  CHEMISTRY.
403
 not be  wafhed off, when placed in the water ap-
 paratus.  It is  likewife neceffary to regifter the
 difference  between the furface of the mercury in
 the ciftern, and that in the jar, and the height "of
 the barometer and thermometer, at  the  end of
 each experiment.
   When all the gas or  gaffes abforbable by wa-
 ter and potafh  are abforbed, water is admitted
 into the jar to difplace the mercury :  and, as is
 defcribed  in  the preceding fection, the mercury
 in  the  ciftern is  to  be  covered by one or two
 inches  of  water.   After  this,  the jar  is to be
 tranfported, by  means of the  flat difh BC, PI. V.
 Fig. 9. into the water apparatus; and the quan-
 tity of  gas  remaining is  to  be afcertained  by
 changing it  into  a graduated  jar.  After this,
 fmall trials of it are to  be made by experiments
in little jars,  to afcertain nearly  the nature of
 the gas  in queftion.  For inftance, into a fmall
jar full ofthe gas, Fig.  8. PI. V. a lighted taper
is introduced.   If the taper  is not immediately
extinguifhed,  we conclude the gas  to contain
oxygen  gas: and, in proportion to the bright-
nefs of the flame,  we may judge if it contains
lefs or  more  oxygen gas  than atmofpheric  air
contains.  If,  on the contrary,  the taper be in-
 ftantly extinguifhed, we  have  ftrong reafon to
 prefume that the refiduum is  chiefly compofed
of  azotic gas.  If, upon the  approach ofthe ta-
 per, the gas takes  fire, and burns quietly  at the 
4°4
ELEMENT S
furface with a white flame, we conclude it to be
pure hydrogen gas.   If this  flame  is blue,  we
judge  it confifts  of carbonated hydrogen gas;
and, if it takes fire with a fudden deflagration,
that it is a mixture of oxygen and hydrogen gas.
If,  again, upon mixing a portion of the refidu-
um with oxygen  gas, red fumes are produced,
we conclude that it contains nitrous gas.
   Thefe preliminary trials  give  feme  general
knowledge of the properties of the  gas, and
nature of the mixture, but are not fufficient to
determine the proportions and quantities of the
feveral gaffes of which it is compofed.  For this
purpofe, all the methods of analyfis muft be em-
ployed ; and, to  direct thefe properly,  it is of
great ufe to  have a previous approximation by
the above methods.   Suppofe, for inftance,  we
know that the refiduum  confifts of oxygen and
azotic gas mixed together,  put a determinate
quantity, ioo parts, into a graduated tube often
or twelve lines diameter,  introduce a folution of
 fulphuret of potafh in contact with the gas, and
leave them together for fome days;  the  fulphu-
 ret abforbs the whole oxygen gas, and leaves the
 azotic gas pure.
    If it is known to contain hydrogen gas, a de-
 terminate  quantity  is  introduced  into  Volta's
 eudiometer,  along with  a known proportion of
 oxygen gas.  Thefe  are deflagrated together by
 means of the electrical fpark.  Frefh portions of 
O F  C H E M I S T R Y.      405
 oxygen  gas are fucceflively added,  till  no far-
 ther deflagration takes place, and till the  greateft
 poffible diminution is produced.  By this  procefs,
 water is formed, which is immediately abforbed
 by the water of the  apparatus.  But, if  the hy-
 drogen gas contain carbon, carbonic acid  is form-
 ed at the fame  time,  which is not  abforbed fo
 quickly.  The quantity of this is readily afcertain-
 ed by afiifting its abforption, by means of agita-
 tion.  If the refiduum contains nitrous  gas, by
 adding oxygen gas,  with which it combines into
 nitric acid, we can very nearly  afcertain its quan-
 tity, from the diminution produced by this mix-
 ture.
   I confine  myfelf to thefe  general examples,
 which are fufficient to give an idea of this kind
of operations.   A  whole volume would not ferve
to explain every poffible cafe.  It is neceffary to
become familiar with  the analyfis of gaffes by
long  experience.  We muft even acknowledge
that they moftly poffefs fuch powerful affinities to
each other, that we are not always certain of ha-
ving feparated them completely.   In thefe cafes,
we  muft vary our experiments in every poffible
point of view ; adding new agents to the combi-
nation, and keeping out others; and muft conti-
nue our trials,  till we are certain of the truth and
exactitude of our conclusions.
                                     SECT. 
406
ELEMENTS
                SECT.   V.

Ofthe neceffary Corrections upon the  Volume of the
  Gaffes, according to the  Preffure  of the Atmof-
  phere.

  All elaftic  fluids are compreflible or conden-
fible, in proportion to the  weight with which
they are loaded.   Perhaps this law, which is af-
certained by general experience, may fuffer fome
irregularity  when thefe fluids are under a degree
of condenfation  almoft fufficient to reduce them
to the liquid ftate,  or when either in a ftate of
extreme rarefaction or condenfation.   But we fel-
dom approach either of thefe limits with moft of
the gaffes which we  fubmit to our experiments.
I understand this proposition of gaffes being com-
preflible, in proportion to their fuperincumbent
weights, as follows.
  A barometer,  which is an  inftrument  gene-
rally known, is,  properly fpeaking,  a fpecies of
fyphon, ABCD, PI. XII. Fig. 16.  whofe leg AB
is filled with mercury, while  the  leg CD is full
of air.   If we fuppofe the  branch CD indefinitely
continued till it  equals the height of our atmo-
fphere, we  can readily conceive that the baro-
meter is, in reality, a fort of balance, in which 
OF  CHEMISTRY.
407
 a column of mercury ftands in equilibrium with
 a column of air of the fame weight.  But it is
 unneceffary to prolongate  the  branch CD  to
 fuch a height; as it is evident that the barome-
 ter being immerfed in air,  the column of mer-
 cury AB will be equally in equilibrium with a
 column of air of the fame diameter, though the
 leg CD be cut off at C, and the part CD be ta-
 ken away altogether.
   The medium  height of mercury  in equili-
 brium with  the weight of a column of air, from
 the higheft part ofthe atmofphere to the furface
 ofthe earth,  is  about twenty-eight French or
 29.85 Englifh inches in the lower parts of  the
 city of Paris : or,  in other words,  the air at the
 furface  of the earth at  Paris,  is ufually preffed
 upon by a weight equal  to that of a column of
 mercury twenty-eight inches in height.  I muft
 be underftood in this way,  in the feveral  parts
 of this publication, when talking ofthe different
 gaffes j  as, for inftance, when the cubical foot of
 oxygen gas  is faid to weigh 538.45 grj. under
 29.85  inches  preffure.    The  height of this
 column of mercury,,  fupported by  the preffure
 of the air,  diminifhes in proportion as we are
 elevated above the  furface of the earth, or rather
 above the level ofthe fea;  becaufe  the mercury
can only form an equilibrium with the column of
air which is above it, and  is not in the fmalleft de-
gree  affected by the air which is below its level. 
4oS         ELEMENTS

  In  what ratio does the mercury in the baro-
meter defcend in proportion to its elevation ? or,
which is the fame thing,  according to what law
or ratio do the feveral ftrata of  the  atmofphere
decreafe  in denfity ?  this queftion, which has
exercifed the ingenuity of natural philofophers
during the laft century, is confiderably elucidated
by the following experiment.
  If we take the glafs fyphon ABCDE, PI. XII.
Fig. 17. fhut at E, and open at A, and introduce
a few drops of mercury,  fo  as to intercept the
communication  of air  between the leg AB and
the leg BE, it is evident,  that the air contained
in BCDE is preffed upon, in common with the
whole furrounding  air,  by  a weight or column
of air equal to 29.85 inches of mercury.   But, if
we pour 29.85  .inches of mercury into  the leg
AB,  it is plain that the air in the branch BCDE
will  then be preffed upon by a weight equal to
twice 29.85  inches of mercury,  or twice  the
weight ofthe atmofphere.  And experience fhews,
that in  this cafe,  the included air, inftead  of
filling the tube from B to E,  only occupies from
C to E,  or exactly one  half of the fpace it filled
before.   If to this  firft column of mercury we
 add two other portions of 29.85 inches  each, in
 the branch AB, the air, in the branch BCDE, will
 be preffed upon by four  times the weight of the
 atmofphere, or four  times  the weight  of 29.85
 inches of mercury.   And it will then only fill the 
OF CHEMISTRY.
  fpace from D to E,  or exactly one quarter of
  the fpace  it occupied at the commencement of
  the experiment.  From thefe experiments, which
  may  be infinitely varied, it has been deduced, as
  a general law of nature, which feems applicable
  to all permanently elaftic fluids,  that they dimi-
  nifli in volume directly in proportion to  the
  weights  with  which  they are preffed ;  or, in o-
  ther words, " the volume of all elaftic fluids is in the
  6f inverfe ratio  ofthe weight by which they are com-
  "preffed."
    The  experiments which have been  made for
 meafuring  the  heights of mountains  by means
 of the barometer, confirm the truth of thefe de-
 ductions:   and, even  fuppofing  them  in fome
 degree inaccurate, thefe  differences  are fo ex-
 tremely fmall, that they may  be reckoned as no-
 thing in chemical experiments.   When  this law
 of the compreflion  of elaftic fluids is once well
 underftood,  it  becomes eafily applicable to the
 corrections,  neceffary in pneumato-chemical ex-
 periments, upon the volume of gas, in relarion to
 its preffure.   Thefe corrections are of two kinds,
 the one relative to  the variations ofthe barome-
 ter,  and  the other for the column of water  or
mercury contained in the jars.   I fhall endeavour
to explain thefe  by examples, beginning with the
moft fimple  cafe.
  Suppofe that  ioo cubical  inches  of oxygen
gas are obtained at inches 54.50 ofthe thermo-
                    Ffr 
4i«
ELEMENTS
meter, and at 30.37 inches of the barometer }
it is required to know  what volume the  100
cubical inches  of gas would occupy, under the
preffure of 29.85 inches,  and what is  the exact
weight of the  100 inches of  oxygen gas ?  Let
the unknown volume, or the number of inches
this gas  would occupy at  29.85  inches of the
barometer, be  expreffed by x; and,  fince the
volumes are in the  inverfe ratio of their fuper->
incumbent weights,  we have the following ftate -
ment: 100 cubical inches is  to x, inverfely as
30.37 inches of preffure is  to 29.85 inches; or
directly  29.85  : 30.37 : : 100 : x « 101.741—
cubical inches, at 29.85 inches barometrical pref-
fure   That is to fay,  the fame gas or air, which
at 30.37  inches of the barometer, occupies 100
cubical inches of volume,  will occupy 101.741
cubical inches, when the  barometer is at 29.85
inches.  It is equally eafy to calculate the weight
of this gas, occupying 100 cubical inches, under
30.37 inches of barometrical preffure; for, as it
correfponds to  101.741  cubical  inches at the
preffure ©f 29.85; and as, at this preffure, and
at 54.50 of temperature,  each  cubical  inch of
oxygen gas weighs 0.311023 gr. it follows,  that
100 cubical inches, under 30.37 barometrical
preffure, muft weigh 31.644 grains.   This con-
clufion might  have been formed more directly;
as, fince the volume of elaftic  fluids is in the
inverfe ratio of their corBpreffion, their weights 
OF  CHEMISTRY.
411
 muft be in the direct ratio of the fame compref-
 fion.  Hence,  fince xoo cubical  inches weigh
 31.1023 grains, under  the preffure of 29.85 in-
 ches, we have  the following ftatement to deter-
 mine the weight of 100 cubical inches of  the
 fame gas at 30.37 barometrical preffure ; 29.85 :
 31.1023 :: 30.37 : x, the unknown quantity, =*=
 31.644.
   The following  cafe  is  more  complicated.
 Suppofe the jar A, PI. XII. Fig. 18. to contain
 a quantity of gas in its  upper  part ACD,  the
 reft of the jar below CD being full of mercury,
 and the whole  ftanding in the  mercurial bafon
 or  refervoir GHIK, filled  with mercury up to
 EF, and that the difference  between the  furface
 CD of  the mercury in  the jar, and EF, that in
 the  ciftern,  is  fix inches,  while the barometer
 ftands at 27.5 inches.  It is evident from thefe
 data, that the  air contained in  ACD is  preffed
 upon by the weight ofthe atmofphere, diminifh-
 ed by the weight ofthe column of mercury CE,
 or by  27.5—6=21.5  inches of  barometrical
preffure.  This air is therefore  lefs compreffed
 than the atmofphere, at the mean  height of the
 barometer;  and  confequently  occupies more
 fpace than it would occupy at the mean preffure;
 the difference being exactly  proportional  to the
 difference  between  the  compreffmg  weights.
 If, then, upon meafuring the fpace ACD, it is
 found to be 120 cubical inches, it muft be  re- 
412
ELEMENTS
duced  to  the volume which  it would occupy
under the mean preffure of 29.85 inches.  This
is done by the following ftatement:  120: x, the
unknown  volume :: 21.5 : 29.85 inverfely; this
gives #= —irpf~ = 86.432 cubical inches.
  In thefe calculations,  we  may either reduce
the height of the mercury in the barometer, and
the difference of level  in the jar and bafon, to
lines, or to decimal  fractions of the inch : but I
prefer the latter, as it is more readily calculated.
As, in  thefe operations,  which frequently recur,
it is of great ufe to have means of abbreviation,!
have given a table in the appendix, for reducing
lines and fractions of lines into decimal fractions
ofthe inch.
  In experiments performed in the water appara-
tus, we muft make fimilar corrections to procure
rigoroufly exact refults, by taking into account,
and making allowance for, the difference of height
ofthe water within the jar, above the  furface of
the water in  the ciftern.   But, as the preffure of
the atmofphere is expreffed in inches  and lines of
the mercurial barometer,  and, as homogeneous
quantities only can  be calculated together, we
muft reduce the obferved inches and lines of wa-
ter into correfpondent heights ofthe mercury.  I
have given a table in the appendix for this con-
verfion, upon  the  fuppofition, that mercury is
 13.5681 times heavier than water.
                                     SECT. 
OF  CHEMISTRY       413
                SECT.  VI.


 Of CorrecJions relative to the Degrees of the Ther-
                   mometer.

   In afcertaining the weight  of gaffes  befides
 reducing them to a mean of barometrical pref-
 fure, as directed  in  the  preceding fection, we
 muft likewife reduce them to a  ftandard ther-
 mometrical  temperature;  becaufe,  all elaftic
 fluids being expanded by heat, and condenfed by
 cold, their  weight in any determinate volume
 is thereby liable  to confiderable alterations.   As
 the temperature of 54.50 is a medium between
 the heat of fummer and the cold of winter,  be-
 ing the temperature of fubterraneous places,  and
 that which is moft eafily approached  to at all
 feafons, I  have chofen that degree as a mean to
 which I reduce air or gas in this fpecies of calcu-
 lation.
  Mr. de  Luc  found that atmofpheric air  was
 increafed T~ Part °f  1Zs  bulk,  by each  degree
of a  mercurial  thermometer, divided into 81
degrees,  between  the  freezing  and  boiling
points. ' This gives ,4t part for each degree of 
4*4
ELEMENTS
Reaumur's thermometer, which is divided  into
80  degrees between thefe  two points;  or 77777?
part of each degree of Fahrenheit's fcale, which
is  divided into 180 degrees between the fame
fixed points.   The experiments of Mr. Mongc
feem to  make this dilation  lefs for hydrogen
gas, which he thinks is  only dilated  -rl^ for
each degree  of Reaumur, or ^4-j. for  each of
Fahrenheit's degrees.   We have not any exact
experiments hitherto publifhed refpecting the ra-
tio of  dilatation of the other gaffes.   But,  from
the trials which have  been made, their dilata-
tion feems  to differ little from  that of atmo-
fpheric. air.  Hence I may take for granted, till
farther experiments give  us better  information
upon this fubject,  that atmofpherical air is dila-
ted ^4-jr Part>  and hydrogen gas ^^  part  for
each degree  of  Reaumur's  thermometer,  or
that atmofpheric  air  is  dilated  —5-7? part, and
hydrogen gas —7; part  for  each degree on  the
fcale of Fahrenheit;  but as  there is  ftill great
uncertainty upon  this  point,  we ought always
 to operate in a temperature  as near as poffible
 to the ftandard of 54.5°.   By this means any er-
 rors in correcting the weight or volume of gaffes
 by reducing them to the  common ftandard,  will
 become of little moment.
    The  calculation  for  this  correction is  ex-
 tremely eafy.  Divide  the obferved  volume of 
       OF CHEMISTRY.        415
air  by  210, for Reaumur's fcale, or 472.5 for
that of Fahrenheit, and multiply the quotient by
the degree of temperature above or below 54.50.
This correction is negative when the actual tem-
perature is above the ftandard, and  pofitive when
below.  By the ufe of logarithmetical tables, this
calculation  is much facilitated.
              SECT.    VII.

Example for calculating the Ccrreclions relative to
    the Variations of Preffure and Temperature.


                 CASE.


  In  the  jar A, PI.  IV.  Fig. 3. ftanding in a
water apparatus, are contained 353 cubical inches
of air.  The furface ofthe water within the jar at
EF is 4! inches above the water in the ciftern :
the  barometer is at 27 inches  9^- lines, and  the
thermometer at 65.750.  Having burned a quan-
tity of phofphorus in the air,  by which concrete
phofphoric acid is produced; the air after the
combuftion  occupies 295  cubical inches;  the
water within the jar ftand.s  7 inches above that in 
4i6          ELEMENTS

the ciftern, the barometer is at  27 inches 9^
lines, and the thermometer at 68°.   It is requi-
red from thefe data  to determine  the actual vo-
lume of air,  before and after combuftion, and
the quantity abforbed during the procefs.
Calculation before  Combuftion.
  The air in the jar before combuftion was 353
cubical inches:  but it was only under a barome-
trical preffure of 27 inches 9-^ lines;  which, re-
duced to decimal fractions,  by Tab. I.  of the
Appendix, gives 27.79167 inches : and from this
we muft deduct the difference of 44 inches  of
water, which, by Tab. II. correfponds to 0.33166
inches of the barometer.  Hence the real preffure
ofthe  air in the jar is 27.46001.   As the vo-
lume of elaftic  fluids diminifhes in  the inverfe
ratio of the comprefling weights, we have the
following ftatement, to reduce the 253 inches to
the volume  the air would occupy at 28 inches
barometrical preffure.
  252 : x, the unknown volume :: 27.46001: 28.
Hence,  x = »j»x»^6oo.  c 346.192 cubical
inches, which  is the volume the fame quantity 
OF  CHEMISTRY.
4^7
 air would have occupied at 28 inches ofthe ba-
 rometer.
   The 472.5th part of this corrected volume is
 .73247,  which,  for the 11.25 degrees of tempe-
 rature above the ftandard,  gives 8.24 cubical in-
 ches ;  and,  as this correction is fubtractive, the
 real corrected volume of the air before combuf-
 tion is 337.952 inches.


          Calculation after Combuftion.


   By a fimilar calculation upon the volume of
 air after combuftion, we find  its barometrical
 preffure  27.77083  — °-5I593  = 27.25490.
 Hence, to have the volume of air under the
 preffure of 28 inches, 295 :  x : : 27.77083 : 28
 inverfely; or, x =  a95X \\ 'u>c = 287.150.
 The 472.5th part of this corrected volume is .61,
 which, multiplied by 13.5 degrees of thermome-
 trical difference,  gives the fubtractive correction
 for temperature,  8.235, leaving the actual  cor-
 rected volume of air after  combuftion  278.915
inches.
Ggg 
418
ELEMENTS
                  Refult.

The corrected volume before combuf-
  tion,         -         -          337.952
Ditto remaining after combuftion,  -  278.915

Volume abforbed during combuftion,    59*037
             SECT.  VIII.

Method  of determining the abfolute Gravity of the
               different Gaffes.


  Take a large balloon A, PI. V. Fig. 10. ca-
pable of holding 17 or 18 pints,  or about half a
cubical  foot,  having the brafs cap bcde ftrongly
cemented to its neck,  and to which the tube and
ftop-cock/g is fixed by a tight-fcrew.  This ap-
paratus  is connected by the double fcrew, repre-
fented feparately at Fig.  12 to the jar BCD, Fig.
10. which  muft be fome pints larger in dimen-
fions  than the balloon.  This jar is open at top,
and is furnifhed with  the brafs cap h i, and the
flop-cock / m.  One of thefe flop-cocks is repre-
fented, feparately at Fig 11. 
OF  CHEMISTRY.
4**
   We firft determine the exact capacity of the
 balloon by filling it with water, and weighing it
 both full and empty.  When emptied of water,
 it  is dried with a  cloth introduced through its
 neck de: and the laft remains of moifture are
 removed  by exhaufting it once  or twice in an
 air-pump.
   When  the  weight  of any gas is to be afcer-
 tained,  this apparatus is ufed as follows.  Fix
 the balloon A to the plate of an air-pump, by
 means of the fcrew of the ftop-cock/ g, which ii
 left open.  The balloon  is to be exhaufted as
 completely as poffible, obferving carefully tho
 degree of exhauftion by means of the barometer
 attached to the air-pump.  When the vacuum is
 formed, the ftop-cock fg is fhut, and the weight
 of  the balloon determined with the moft fcru-
 pulous exactitude.  It is then fixed to the jar
 BCD, which  we fuppofe placed in  v/ater in
 the fhelf  of the  pneumato-chemical apparatus
 Fig. i. ;the jar  is  to be filled with the gas we
 mean to weigh;  and then, by opening the ftop-
 cocks fg and  / m, the gas afcends into the  bal-
 loon,  whilft the  water of the ciftern rifes at the
 fame time into  the jar.  To avoid very trouble-
 fome  corrections, it is neceffary, during this firft
 part of the operation, to fink the jar in the cif-
tern till the furfaces  of the water within  and
without  the jar exactly correfpond.   The ftop- 
420
ELEMENTS
cocks are again fhut: and the balloon, being un-
fcrewed from its connection with the jar, is to
be carefully weighed.   The difference  between
this weight and that of the exhaufted balloon, is
the precife weight of the air or gas contained in
the balloon.  Multiply this weight by 1728, the
number of cubical inches in a cubical foot, and
divide  the product by  the number of cubical
inches  contained in the balloon, the quotient is
the weight of a cubical foot of the gas or air fub-
mitted to experiment.
  Exact account muft be kept of the barometri-
cal  height and the temperature ofthe thermome-
ter during the above experiment; and from thefe
the refulting  weight of a cubical foot is eafily
corrected  to the ftandards of 28 inches preffure,
and 54.5Q  temperature, as directed in the pre-
ceding fection.  The fmall portion of air remain-
ing in the balloon after forming  the vacuum,
muft  likewife be attended to : and  this is eafily
determined by the barometer attached to the air-
pump.  If that barometer, for inftance, remains
at the  hundredth part of the height it ftood at
before the vacuum was formed, we conclude that
one hundredth part of^he air originally contain-
ed, remains in the balloon, and confequently that
only Ty^-of gas was introduced from the jar into
the balloon. 
OF'CHEMISTRY,
421
              CHAP    III.


 Defcription  of the Calorimeter,  or apparatus for
               meafuring Caloric.

      THE calorimeter, or apparatus for meafuring
       the relative quantities of heat contained in
 bodies, was defcribed by Mr de la Place and
 me in the Memoirs of the Academy  for  1780,
 p. 355 : and from that Effay the materials of this
 chapter are extracted.
   If, after having cooled any body to  the  free -
 zing point, it be expofed  in an  atmofphere of
 88.250, the  body will gradually become heated,
 from the  furface inwards,  till at laft it acquire
 the fame temperature with the  furrounding air.
 But, if apiece of ice be placed in the fame fitua-
 tion,  the circumftances  are  quite different.  It
 does not approach in the fmalleft degree towards
 the temperature of the circumambient air;  but
 remains conftantly at 320, or the temperature of
 melting ice,  till the laft portion of ice  be com-
pletely melted.
  This  phenomenon  is readily explained; as,
to melt ice, or reduce it to water, it requires to
be combined with a  certain portion of caloric, 
422
ELEMENTS
the whole caloric attracted from the furrounding
bodies, is  arrefted or fixed at the furface or ex-
ternal layer  of ice which  it is employed  to dif-
folve, and combines with it to form water ; the
next quantity of caloric combines with the fe-
eond layer to diffolve it  into water, and  fo on
fucceffively  till  the  whole ice  be diffolved, or
converted into water, by combination with calo-
ric : the very laft atom ftill remaining at its for-
mer temperature, becaufe the caloric  could ne-
ver penetrate fo far, while any intermediate ice
remained to melt, or to combine with.
   Upon thefe principles, if we conceive a hol-
low  fphere  of  ice at  the temperature of 32°
placed in  an atmofphere of 54.5°, and contain-
ing a fubftance at any degree of temperature
above freezing ; it follows, that the heat of the
external atmofphere cannot  penetrate into the
internal hollow  of the fphere of ice; and, that
the heat ofthe body which is placed in the hol-
low ofthe fphere, cannot penetrate outwards be-
yond it, but will be  flopped at the internal fur-
face, being continually employed to melt fuc-
ceffive  layers  of ice,  until the temperature of
the body be reduced to 320  by  having all  its
fuperabundant caloric, above  that temperature,
carried off  to melt the ice.  If the  whole wa-
ter, formed within the fphere of ice  during the
reduction of the  temperature  of the included
body to 320, be carefully collected,  the  weight 
OF  CHEMISTRY.
4*3
 ofthe water will be exactly proportional to the
 quantity of caloric loft by the  body, in paffing
 from its original temperature to that of melting
 ice;'for it is evident, that a  double  quantity of
 caloric would  have melted  twice the quantity
 of ice.   Hence the quantity  of ice melted  is a
 very exact meafure of the proportional quantity
 of caloric employed to produce that  effect,  and
 confequently ofthe quantity loft by the only fub-
 ftance that could poffibly have fupplied it.
   I have made this fuppofition, of what would
 take place in a  hollow fphere  of ice, for the  pur-
 pofe of more readily explaining the method ufed
 in this  fpecies  of experiment, which  was  firft
 conceived by Mr de la Place.  It would be  dif-
 ficult to procure fuchfpheres  of ice,  and incon-
 venient to make ufe of them when  got; but, by
 means of the following apparatus,  we have re-
 medied  that defect.   I  acknowledge the name
 of Calorimeter, which I have given it, as derived
 partly from Greek and partly from Latin,  is in
 fome degree open to criticifm.  But, in matters
 of fcience, a flight deviation from ftrict etymolo-
 gy, for the  fake of giving diftinctnefs of idea, is
 excufable :  and I could not derive the name en-
 tirely from Greek without approaching too  near
 to the names of known inftruments employed for
other purpofes.
  The calorimeter is reprefented in PI. VI.   It is
fhewn in perfpective  at Fig. i.  and its interior 
424
ELEMENTS
 ftructure is engraved at Fig. 2 and 3.; the for-
 mer being horizontal,  and the latter a perpen-
 dicular fection.  Its capacity or cavity is divi-
 ded into three parts,  which, for  better  diftinc-
 tion,  I fhall name the interior,  middle, and ex-
 ternal cavities.  The interior cavity////, Fig.
 4. into which the fubftances  fubmitted to expe-
 riment are put, is compofed of a grating or cage
 of  iron  wire, fupported by feveral iron  bars.
 Its  opening, or mouth,  LM, is covered by the
 lid  HG, which is compofed ofthe fame materials.
 The middle cavity bbbb, Fig 2.  and  3. is in-
 tended to contain the  ice which fnrrounds the
 interior  cavity, and  which  is intended  to be
 melted by the caloric of the fubftances employed
 in  the experiment.   The ice is  fupported by
 the grate m m  at the bottom  of  the  cavity,
 under which is  placed  the  fieve  n n.   Thefe
 two are  reprefented feparately  in  Figures 5.
 and 6.
  In  proportion as  the  ice  contained in the
 middle cavity  is melted, by the caloric difenga-
 ged from the body placed in the interior cavity,
 the  water runs through  the grate and fieve,  and
 falls through the conical funnel c c d, Fig. 3 and
 the  tube xy, into the receiver F,  Fig.  1.   This
 water may be retained or let  out at pleafure, by
 means ofthe ftop-cock u.   The external cavity
aaaa, Fig. 2. and 3.  is filled with ice, to pre-
 vent any effect upon the ice  in the middle ca- 
OF, CHEMISTRY.
425
  vity from the heat of the furrounding air;  and
  the water produced from it is carried off through
  the pipe ST,  which  fhuts by means ofthe ftop-
  cock r.  The whole machine is covered by the
  lid FF, Fig. 7, which is  made of tin, and painted
  with oil colour, to prevent ruft.
    When this machine is employed, the middle
  cavity bbbb, Fig. 2 and 3. the  lid GH, Fig. 4.
  of the interior cavity, the external cavity a a a a,
  Fig. 2. and 3. and the  general lid FF, Fig. 7.
  are  all filled with pounded ice, well  rammed,
  fo that no void fpaces remain, and  the ice of the
 middle cavity is allowed to drain.  The machine
 is  then opened, and  the fubftance fubmitted to
 experiment being placed in the interior cavity,
 it  is  inftantly clofed.  After  waiting till the in^
 eluded body is completely cooled  to the freez-
 ing point, and  the whole melted  ice has drained
 from the middle cavity,  the water collected in
 the veffel F,  Fig.  1.  is accurately  weighed.
 The  weight of the  water produced during the
 experiment is an exact  meafure of the  caloric
 difengaged during  the cooling of  the included
 body  ; as this fubftance  is evidently in a fimilar
 fituation with the one  formerly mentioned as in-
 cluded in a hollow  fphere of ice.  The whole ca-
loric difengaged from  the included body is flop-
ped by the ice  in  the middle cavity:  and that
ice  is preferved from being affected by any other
                 Hhh 
426
ELEMENT S
heat by means of the ice contained in the gene-
ral lid, Fig. 7. and in the external cavity.   Ex-
periments of this kind generally laft from fifteen
to twenty hours:  but they are fometimes accele-
rated by covering up the fubftance in the interior
cavity  with well drained ice,  which haftens its
cooling.
 . The fubftances to be operated upon are placed
in the thin iron bucket, Fig. 8. the cover of which
has an opening fitted with a  cork,  into which a
fmall thermometer is fixed.  When we ufe acids,
or other fluids capable of injuring  the metal of
the inftruments, they are contained in the matrafs,
Fig. 10. which has a  fimilar thermometer in a
cork fitted to its  mouth, and  which ftands in the
interior cavity, upon the fmall cylindrical fupport
RS, Fig. 10.
   It is abfolutely requifite, that there be no com-
 munication  between  the external and middle
 cavities of the calorimeter; otherwife the  ice
 melted by  the influence of  the furrounding air,
 in  the external cavity, would mix with the wa-
 ter produced from the ice of the middle cavity,
 which would no longer be a  meafure ofthe calo-
 ric loft by the fubftance fubmitted to experiment.
   When the temperature  of the  atmofphere is
 only a few degrees above the freezing point,  its
 heat  can hardly reach the middle cavity,  being
 arretted by the  ice of the cover,  Fig. 7. and of
 the external cavity.   But,  if the  temperature of 
OF  CHEMISTRY
427
 the air be under the degree of freezing, it might
 cool the ice contained in the middle cavity, by
 caufing the ice in the external cavity  to fall, in
 the firft place, below 320.  It is therefore effen-
 tial, that this experiment be carried on  in a tem-
 perature fomewhat above freezing.  Hence, in
 time of froft, the calorimeter muft  be kept in an
 apartment carefully heated.   It is likewife necef-
 fary, that the ice employed be not under 320 ; for
 which  purpofe it muft be pounded, and fpread
 out thin for fome time, in a place where the tem-
 perature is higher.
   The ice of the interior cavity always retains a
 certain quantity of water adhering  to its furface,
 which may be fuppofed to belong to the refult of
 u:e experiment.  But as, at the beginning of each
 experiment,  the ice is already faturated with as
 much water as it can contain, if any ofthe wa-
 ter produced by the caloric fhould remain attach-
 ed  to  the ice,  it is evident, that very nearly an
 equal quantity of what adhered to  it  before the
 experiment muft have run down into the  veffel F
 in  its ftead;  for  the  inner furface  of the ice in
 the middle  cavity  is very little changed during
 the experiment.
  By any contrivance that could, be devifed, we
could not prevent the accefs of the external air
into  the  interior cavity, when the atmofphere
was at 520 or 540.   The air confined in the ca-
 vity  being in that cafe fpecifically  heavier than 
428          ELEMENTS

the external air, efcapes  downwards through the
pipe * y,  Fig.  3. and is replaced by the warmer
external air,  which, giving out its  caloric to the
ice, becomes heavier, and finks in its turn.   Thus
a current of air is  formed through the machine,
which is the more rapid in proportion as the ex-
ternal air  exceeds the internal in temperature.
This  current of  warm air muft  melt a part of
the  ice, and injure the accuracy of  the experi-
ment.  We  may,  in  a great  degree, guard a-
gainft this fource of error, by keeping the ftop-
cock  u continually fhut.  But it is better to ope-
rate only when the temperature of the external air
does not exceed 39°, or at moft 41 ° ; for we have
Obferved,  that, in this cafe, the melting of the
interior ice by the atmofpheric air is perfectly in-
fenfible; fo that we may anfwer for the accuracy
of our experiments upon the fpecific heat  of bo-
dies to a  fortieth part.
   We have caufed two of the above defcribed
machines to be  made.   One, which is intended
for fuch experiments as do not require the  interi-
 or air to be renewed, is formed precifely accord-
 ingto the defcription  here given.  The  other,
 which anfwers for experiments upon combuftion,
 refpiration, &c. in which frefh quantities of air
 are indifpenfibly neceffary, differs from the for-
 mer in having two fmall tubes in the two lids, by
 which a current of atmofpheric air may be blown
 into the interior cavity ofthe machine. 
OF  CHEMISTRY.
4*9
   It is extremely eafy, with this  apparatus,  to
 determine the phenomena which  occur in ope-
 rations where caloric is either difengaged or ab-
 forbed.   If we wifh, for inftance, to afcertain the
 quantity ofthe caloric which is difengaged from
 a folid body,  in cooling a certain number of de-
 grees ; let its temperature be firft raifed to 2120 :
 it is then  placed  in  the interior cavity ffff,
 Fig. 2 and 3.  of  the calorimeter, and allowed
 to remain till we are  certain  that  its tempera-
 ture is reduced  to  32" : the water produced by
 melting the ice during its cooling,  is collected,
 and  carefully weighed : and this weight, divided
 by the volume ofthe body fubmitted to experi-
 ment, and multiplied into the degrees of tempe-
 rature which it had above 32°  at the commence-
 ment ofthe experiment, gives the  proportion of
 what the Englifh philofophers  call  fpecific heat.
   Fluids are contained in  proper veffels,  whofe
 fpecific heat has been previoufly afcertained ; and
 are  operated  upon  in the machine in the fame
 manner as directed for folids ; taking care to de-
 duct, from the quantity of water melted during
 the experiment, the  proportion which belongs to
 the fpecific heat  ofthe  containing veffel.
   If  the quantity of caloric difengaged during
 the combination  of different fubftances is  to be
determined,  thefe fubftances are to  be previoufly
reduced to the freezing degree  by keeping them, 
 43o          ELEMENTS

 a  fufficient time furrounded with pounded ice:
 The mixture  is then to be made in the inner
 cavity ofthe calorimeter, in a proper veffel like-
 wife reduced to 320 ; and they are kept inclofed
 till the temperature  ofthe combination has re-
 turned to the fame degree.   The quantity of wa-
 ter produced is a meafure of the caloric difenga-
 ged during the combination.
   To determine the quantity of caloric difen-
 gaged during combuftion,  and during  animal
 refpiration, the combuftible bodies arc burnt, or
 the animals are  made to  breathe, in the inte-
 rior cavity, and  the  water produced  is carefully
 collected.  Guinea-pigs, which refift the effects
 of cold extremely well,  are well adapted for this
 experiment.   As the continual renewal of air is
 abfolutely  neceffary  in fuch experiments,  we
 blow frefh  air into the interior cavity of the ca-
 lorimeter by means  of a pipe deftined for that
 purpofe ; and allow it to efcape through another
 pipe ofthe fame kind :  and that the  heat of this
 air may  not produce errors in the refults of the
 experiments, the tube, which conveys it into the
 machine, is made to pafs  through pounded ice,
 that it may be reduced to 320 before  it arrives at
 the calorimeter.   The air which  efcapes, muft
 likewife  be made to  pafs  through  a tube fur-
 rounded  with ice, included in the interior cavi-
ty ofthe  machine : and the water which is there
produced muft make  a part of what is collected ; 
       OF  CHEMISTRY.       431

 becaufe  the  caloric difengaged from this air is
 part ofthe product ofthe experiment.
   It is fomewhat more difficult to determine the
 fpecific caloric contained in the different gaffes,
 on account of their fmall degree of denfity; for,
 if  they are only  placed  in  the  calorimeter in
 veffels like other fluids, the quantity of ice melt-
 ed is fo fmall, that the refult of the experiment
 becomes at beft very uncertain.   For this fpecies
 of experiment we have contrived to make the
 air pafs  through two metallic  worms,  or fpiral
 tubes.  One of thefe, through which the air paf-
 fes, and becomes heated in its way  to the calo-
 rimeter, is contained  in a veffel full of boiling
 water: and the other, through which the air cir-
 culates within  the  calorimeter to difengage its
 caloric, is placed in the interior cavity, ffff, of
 that machine.   By means  of a fmall thermome-
 ter placed at one end of the fecond worm, the
 temperature of the air, as it enters the calori-
 meter  is determined :  and its  temperature  in
 getting out ofthe interior cavity, is found by an-
 other thermometer placed at the other end  of
 the worm.  By this contrivance- we are enabled
 to afcertain the quantity of ice melted by deter-
 minate quantities of air or gas, while  lofing a
 certain number of  degrees  of temperature,  and,
 sonfequently, to determine their feveral degrees
of fpecific caloric.   The  fame apparatus,  with
fome  particular  precautions, may be  employed 
43*
ELEMENTS
to afcertain  the  quantity of caloric difengaged
by the condenfation of the vapours  of different
liquids.
   The various experiments which may be made
with the calorimeter, do not afford abfolute con-
clusions,  but only give us the  meafure of rela-
tive quantities.   We have therefore  to fix a unit,
or ftandard  point, from whence to form a fcale
ofthe feveral refults.   The quantity of caloric
neceffary to  melt a pound of ice has been chofen
as this unit: and, as it requires a pound  of water
ofthe temperature of  1670 to  melt a  pound of
ice, the quantity of caloric expreffed by our unit
or ftandard point is what raifes a pound of wa-
ter from 320 to 1670.  When this  unit is once
determined, we  have only to exprefs the  quan-
ties of caloric difengaged from  different  bodies,
by cooling a certain number of degrees, in analo-
gous values.  The following is an eafy  mode of
calculation for this purpofe, applied  to one of our
earlieft experiments.
  We took 7 lb. 11  oz. 1 gros  2& Srs' or* plate_
iron,  cut into narrow  flips,  and rolled  up; or,
expreffing  the  q  antity in decimals, 7.7070319
lbs.   Thefe being heated in  a bath of boiling
water to about 207.5°,  were quickly introduced
into the interior cavity of the calorimeter.  At
the end of eleven hours, when the  whole quan-
tity  of water melted from the ice had thorough-
ly drained off,  we found that 1.109795 pounds 
OF CHEMISTRY.
433
   pounds of ice were melted.   Hence, the caloric
   difengaged from the iron by cooling 175.50 na"
   ving melted 1.109795 pounds of ice, how much
   would have been melted by cooling 1350 ? This
   queftion gives the following  ftatement in direct
   proportion, 175.5: 1.109795:: 135:^=0.85384.
   Dividing this quantity by the weight ofthe whole
   iron employed,  viz.  7.7070319,  the quotient
  0.1109  is the quantity of ice which would have
  been melted by one pound of iron while cooling
  through 135 degrees of temperature.
    Fluid  fubftances, fuch as fulphuric and  nitric
  acids, &c. are contained in a matrafs, PI. VI. Fig.
  9.  having  a thermometer adapted  to the cork,
  with its bulb immerfed in the liquid.   The ma-
  trafs is placed  in a bath of boiling water; and
 when, from the thermometer, we judge the liquid
 is raifed to a proper temperature, the matrafs  is
 placed in the calorimeter.  The calculation ofthe
 products, to determine the fpecific caloric of thefe
 fluids, is made as above directed,  taking care to
 deduct from the water  obtained, the  quantity
 which would have  been produced by the matrafs
 alone, which muft be afcertained by a previous ex-
 periment.   The  table ofthe refults obtained by
 thefe experiments is omitted, becaufe not yet fuf-
 ficiently complete; different circumftances having
 occafioned the feries to be interrupted. It is not,
however, loft fight  of; and  we are  lefs or more
employed upon the fubject every winter.
                   Iii 
434
ELEMENTS
              CHAP.   IV.

Of Mechanical Operations for  the Divifion   of
                    Bodies.
             SECT.    I.


  Of Trituration, Levigation, and Pulverization.

     THESE are,  properly fpeaking, only preli-
      minary mechanical operations for dividing
and feparating the particles of  bodies, and redu-
cing them into very fine  powder.   Thefe ope-
rations can never reduce  fubftances  into their
primary,  or elementary  and ultimate particles.
They do not even deftroy the aggregation of bo-
dies ; for every particle, after the moft accurate
trituration,  forms a fmall whole, refembling the
original mafs  from which it  was divided.   The
real chemical operations,  on the contrary, fuch
as folution, deftroy the aggregation of bodies,
and feparate their conftituent and integrant par-
ticles from each other. 
OF  CHEMISTRY.
435
  Brittle  fubftances are reduced to powder by
means of peftles and  mortars.   Thefe  are  of
brafs or iron, PI. I. Fig.  i. ;  of marble or gra~
nite, Fig.  2.; of lignum vitas, Fig. 3. j of glafs,
Fig. 4. ; of agate,  Fig.  5. ;  or of porcelain,
Fig. 6.   The peftles for each  of thefe arc repre-
fented in the plate, immediately below the mor-
tars to which they refpectively belong; and are
made of  hammered  iron  or brafs,  of wood,
glafs,  porcelain,  marble,  granite,  or  agate,
according to the nature of the fubftances they
arc  intended to  triturate.  In every laboratory,
ic is requifite  to have  an affortment of thefe
utenfils, of various fizes  and  kinds.-  Thofe  of
pc  celain  and glafs can only  be ufed for rub-
bing  fubftances  to  powder,  by a dextrous ufe
ofthe peftle round the fides ofthe mortar ;  as it
would be  eafily  broken  by reiterated blows  of
the  peltle.
  The bottom of mortars ought to be made  in
form of a hollow fphere,  and  their fides  fhould
have  fuch a degree  of inclination as  to make
the  fubftances they contain  fall back to the bot-
tom when the peftle is lifted,  but not fo perpen-
dicular as  to collect  them  too much  together;
otherwife  too large a quantity would get below
the peftle,  and  prevent its  operation.   For this
reafon, likewife, too large a quantity ofthe fub-
ftance to be powdered ought  not to be put into
the  mortar at''one time :  and wc  muft  from 
436
ELEMENTS
time to time get rid of the particles already re-
duced to powder, by means of fieves to be af-
terwards defcribed.
  The  moft ufual  method of levigation is by
means of a flat table ABCD, PI. I. Fig. 7. made
of porphyry, or fome other ftone of fimilar hard-
nefs.  On  this the fubftance  to  be reduced to
powder is fpread ; and is then bruifed and rub-
bed by a muller M, of the fame  hard materials,
the bottom of which is made  a fmall portion of
a large fphere.  And, as the muller tends conti-
nually to drive the fubftances towards the fides of
the table, a thin flexible knife, or fpatula, of iron,
horn, wood, or ivory, is ufed for bringing them
back to the middle of the ftone.
  In large works,  this operation  is performed
by means of large rollers of hard ftone,  which
turn upon each other, either  horizontally, in the
way of corn-mills, or by one vertical roller turn-
ing upon a  flat-ftone.   In the above operations,
it is often requifite to moiften the fubftances a lit-
tle, to prevent the fine powder from flying off.
  There are  many bodies which  cannot  be re-
duced to powder by  any of the  foregoing  me-
thods ; fuch  are  fibrous fubftances, as  woods,
fuch fubftances as are tough and elaftic,  as the
horns of animals, elaftic gum, &c. and the mal-
leable metals, which flatten  under the  peftle,
inftead of being reduced to powder.   For redu- 
OF  CHEMISTRY.
437
cing the woods to powder, rafps, as in PI. I. Fig.
8. are employed.   Files of a finer kind are ufed
for horn;  and ftill finer,  PI. I. Fig. 9. and 10.
for metals.
   Some ofthe metals, though not brittle enough
to  powder under the peftle, are too foft to be
filed, as they clog the file, and prevent its opera-
tion.   Zinc is one of thefe :  but it may be pow-
dered, when hot, in  a heated iron mortar ; or it
may be rendered  brittle, by alloying it with a
fmall quantity  of mercury. One or other of thefe
methods is ufed by fire-work makers for produ-
cing a blue flame by means of zinc.   Metals may
be reduced into grains,  by pouring them when
melted into water ; which method ferves  very
well when they are not wanted  in fine powder.
   Fruits,  potatoes, &c,  of  a pulpy and fibrous
nature, may be reduced to pulp by means  ofthe
grater,  PI. I. Fig. 11.
   The choice ofthe different fubftances of which
thefe inftruments are  made,  is  a matter of im-
portance.   Brafs or  copper are unfit for opera-
tions upon fubftances to be ufed as food or in phar-
macy ; and marble or metallic inftruments muft
not be ufed for acid fubftances. Hence mortars of
very hard wood,  and  thofe of porcelain, granite,
or glafs, are of great utility in many operations. 
438         ELEMENTS
               SECT.  II.

  Of  Sifting and Wafhing Powdered Subftances.

  None ofthe mechanical operations, employed
forjeducing bodies to powder, are capable of pro-
ducing it of an equal degree of finenefs through-
out :  The  powder obtained by  the longeft and
moft  accurate trituration being ftill  an affem-
blage of particles of various fizes.   The coarfer
of thefe are removed,  fo  as only to leave the
finer and more homogeneous particles, by means
of fieves, PI. I. Fig. 12/13, 14, 15. of different
fineneffes, adapted to the particular purpofes they
are intended for.   All the  powdered matter
which is larger than the interftices of the fieve
remains behind, and is  again fubmitted to the
peftle, while the finer paffes  through.   The fieve
Fig. 12. is  made of hair-cloth, or of filk-gauze :
and the one reprefented Fig. 13. is of parch-
ment pierced with round holes of a proper fize.
This latter is employed in the  manufacture of
gun-powder.  When very fubtile or  valuable
materials  are to  be  fifted,  which  are eafily
difperfed, or when the finer parts of the powder
may be hurtful,  a compound fieve,  Fig. 15. is
made ufe of, which confifts ofthe fieve ABCD, 
        OF  CHEMISTRY.     439

with a lid EF, and  receiver GH; thefe three
parts are reprefented as joined together for ufe,
Fig. 14.
  There is  a  method  of procuring powders of
an  uniform  finenefs, confiderably more accu*
rate than the  fieve; but it  can  only be ufed
with fuch fubftances as  are  not acted upon by
water.   The powdered fubftance is mixed and
agitated with  water, or any other convenient
fluid.  The liquor  is allowed to fettle for a few
moments, and  is then decanted off.  The coarfer
powder remains at the bottom of the veffel,  and
the finer paffes over with the liquid.  By  re-
peated decantations  in this manner,  various  fe-
diments  are obtained,   of different degrees of
finenefs;  the  laft fediment, or that which  re-
mains longeft fufpended in the liquor,  being  the
fineft.   This procefs may likewife be  ufed with
advantage for  feparating fubftances  of different
degrees of fpecific gravity,.though of the fame
finenefs. This laft is chiefly employed in mining,
for feparating the  heavier metallic ores from  the
lighter earthy matters with which they are mixed.
  In chemical laboratories, pans and jugs of glafs
or earthen-ware, are employed for this operation.
Sometimes,  for decanting the liquor without dif-
turbing the fediment, the glafs fyphon ABCHI,
PI. II.  Fig. 11. is  ufed,  which may be  fupported
by  means of the  perforated  board DE,  at the 
44o           ELEMENTS

proper depth in the veffel FG, to draw off all
the liquor required into the receiver LM.  The
principles and application of this ufeful inftru-
ment are fo well known, as to need no explana-
tion.



                SECT.  III.

                 Of Filtration.

   A filtre is a fpecies of very fine fieve, which is
permeable to the particles of fluids, but through
which the particles ofthe fineft powdered folids
are incapable of paffing; hence its ufe in fepara-
ting fine powders  from fufpenfion in fluids.   In
pharmacy,  very clofe and fine woollen cloths are
chiefly ufed for this operation.  Thefe are com-
 monly formed in  a conical fhape, PI. II. Fig. 2.
which has the advantage of uniting all the liquor
which drains through,  into a point A, where it
 may be readily collected in a narrow mouthed
 veffel.   In large pharmaceutical laboratories, this
 filtring  bag is ftretched upon a wooden-ftand,
 PI. II. Fig. 1.
   For the  purpofes of chemiftry, as it is requi-
 fite to have the  filtres perfectly  clean, unfized
 paper is fubftituted inftead of cloth or  flannel ; 
         OF  CHEMISTRY.       441

 through this  fubftance, no folid body, however
 finely it be powdered,  can penetrate,  and fluids
 percolate  through it with the greateft readinefs.
 As  paper  breaks eafily  when  wet, various me-
 thods of fupporting it are ufed, according to cir-
 cumftances.   When  a large quantity of fluid is
 to be filtrated,  the  paper is  fupported by the
 frame of wood, PI. II. Fig. 3.  ABCD, having a
 piece of coarfe cloth  ftretched over it,  by means
 of iron-hooks.  This cloth muft be well cleaned
 each time it is ufed;  or even new cloth muft be
 employed, if  there be reafon to fufpect its  being
 impregnated with any thing which can injure the
 fubfequent operations.   In  ordinary operations,
 where moderate quantities of fluid are to be fil-
 trated,  different  kinds of glafs funnels are ufed
 for fupporting the paper, as reprefented PI. II
 Fig. 5. 6. and 7.   When feveral nitrations muft
 be carried on at once, the board or fhelf AB,
 Fig.  9. fupported upon ftands  C and  D,  and
 pierced with round holes, is very convenient for
 containing  the funnels.
   Some  liquors  are  fo thick  and  clammy, as
 not to be able to penetrate through  paper with-
 out fome previous preparation, fuch  as clarifica-
 tion  by means of white of  eggs, which,  being
 mixed with the liquor, coagulates when brought
to boil; and, entangling the greater part of the
 impurities  of the liquor, rifes with them to the
                  K k k 
44,       .   ELEMENTS

furface  in  the ftate of fcum.   Spiritous liquors
may be clarified in the fame manner by means
ofifinglafs diffolved in water, which coagulates
by the  aftion ofthe alkohol without the afliftance
of heat.                                 .
   As moft of the acids are produced  by diftil-
lation,  and are confequently clear, we have rarely
any occafion to filtrate them.  But if, at any time,
 concentrated acids require this operation, it is im-
 poflible to employ paper, which would be corrod-
 ed and deftroyed by  the acid.  For this purpofe,
 pounded glafs, or rather quartz or rock-cryftal,
 broken in pieces, and grofsly powdered, anfwers
 very well.   A few of the larger pieces  are put in
 the neck of the  funnel:  thefe are covered  with
 the fmaller pieces; the finer powder is placed over
  all • and the acid is poured on at top.   For the
  ordinary purpofes of fociety, river-water is fre-
  quently filtrated by  means of clean walhed  fand,
  to feparate its impurities, or by means of certain
  porous ftones, called filtering  ftones,  cut into a
  convenient form.

                  SECT.  IV.

                  Of Decantation.

     This operation is often fubftituted, inftead of
   filtration for feparating folid particles which are 
OF  CHEMISTRY.
443
 diffufed through liquors.  Thefe are allowed to
 fettle in conical veffels, ABCDE, PI. II. Fig. 10.
 the diffufed matters gradually fubfide,  and the
 clear fluid is gently poured off.   If the fediment
 be extremely light, and apt to mix again with the
 fluid by the flighteft motion, the fyphon, Fig. 11.
 is ufed, inftead of decantation,  for  drawing off
 the clear fluid.
   In experiments, where the weight of the pre-
 cipitate muft be rigoroufly afcertained, decanta-r
 tion is preferable to filtration, providing the preci-
 pitate  be  feveral  times wafhed in a confiderable
 proportion of water.   The weight of the precipi-
 tate may  indeed be  afcertained,  by carefully
 weighing the filtre before and  after the operation.
 But, when the quantity of precipitate is fmall, the
different proportions of moifture retained by the
paper, in a greater or leffer degree of exficcation,
may prove a material fource of error, which ought
carefo^v to be guarded againft.
CHAP. 
444
ELEMENTS
              CHAP   V.

Of Chemical Means for feparating the Particles of
   Bodies from each other,  without  Decompofition,
   and for uniting them again.

I Have already fhewn, that there are two me-
    thods of dividing the particles of bodies, the
mechanical  and chemical.   The  former only  fe-
parates  a  folid mafs  into  a  great number  of
fmaller maffes;  and for thefe purpofes various
fpecies of forces are employed, according to cir-
cumftances, fuch as the ftrength of man or  of
animals, the weight of water applied through
the means of hydraulic engines,  the  expanfive
power of fleam,  the force of the wind, &c.  By
all or any of thefe mechanical powers, however,
we can never reduce fubftances into powder be-
yond a certain degree of finenefs : and the fmalleft
particle produced in this way, though it feems very
minute to our organs,  is ftill in fact a mountain,
when  compared with the ultimate elementary
particles of the pulverized fubftance.
   The chemical agents, on the contrary,  divide
bodies into their primitive particles.   If, for  in-
ftance, a neutral fait be acted upon  by thefe, it
is divided, as far as is poffible,  without ceafing 
OF  CHEMISTRY.
445
 to be a neutral fait.   In this Chapter, I mean to
 give examples of this kind of  divifion of bodies,
 to which I fhall add fome  account of the relative
 operations.


               SECT.   I.

             Ofthe Solution of Salts.

   In  chemical  language,  the terms  of folution
 and diffolution have long been confounded;  and
 have  very improperly been indifcriminately em-
 ployed for exprefling both  the divifion of the
 particles of a fait in a fluid, fuch, as water, and
 the divifion of a metal  in an acid.   A few re-
 flections  upon  the  effects of thefe two opera-
 tions  will  fuffice  to fhow that they ought not
 to be  confounded  together.  In  the folurion of
 falts, the faline particles  are  only  feparated from
 each other, while  neither  the fait nor the water
 are at all decompofed; for  we are able to recover
 both the one and the other in the fame quantity
 as before the operation.   The fame thing takes
place  in the folution of refins in  alkohol.   Du-
ring metallic diffolutions, on the  contrary,  a
decompofition, either of the acid, or of the wa-
ter which  dilutes it,  always takes place.   The
metal combines with oxygen; and is  changed 
446
ELEMENTS
into an oxyd ; and a gaffeous fubftance is difen-
gaged ; fo  that in reality none of the fubftan-
ces employed remain, after the operation,  in the
fame ftate they were in before.  This article is
entirely confined to the confideration  of folu-
tion.
   To underftand properly what takes place du-
ring the folution of falts, it is neceffary to know,
that, in moft of thefe  operations,  two diftinct
effects arc complicated together, viz. folution by
water, and folution by caloric: and, as the ex-
planation of moft of the phenomena of folution
depends upon the  diftinction of thefe  two cir-
cumftances, I fhall enlarge a little upon their na-
ture.
   Nitrat of potafh, ufually  called nitre or falt-
petre,  contains very little water of cryftalliza-
tion, perhaps even none at all.  Yet  this fait li-
quefies in a  degree of heat very little fuperior to
that of boiling water.   This liquefaction cannot
therefore be produced  by means of the water of
cryftallization, but in confequence ofthe fait be-
ing very fufible in its nature, and from its paffing
from the folid to the liquid ftate of aggregation,
when but a little raifed above the temperature of
boiling water.   All falts are in this manner fuf-
ceptible of being liquefied  by caloric,  but in
higher or lower degrees of  temperature.   Some
of thefe, as the acetites of potafh and foda,  li-
quefy  with  a very moderate heat;  while others, 
OF  CHEMISTRY.
447
 as fulphat of potafli,  or of lime,  Sec. require the
 ftrongeft fires we are capable of producing.  This
 liquefaction of falts  by caloric produces exactly
 the fame phenomena with the melting of ice.  It
 is accompliihed in each fait by a determinate de-
 gree of heat,  which remains invariably the fame
 during the whole time ofthe liquefaction.   Ca-
 loric is employed, and becomes fixed during the
 melting ofthe fait; and is,  on the contrary, dif-
 engaged when the  fait  coagulates.   Thefe are
 general phenomena, which univerfally occur du-
 ring the paffage of every fpecies of fubftance
 from the folid to the fluid ftate  of aggregation,
 and from fluid to folid.
   Thefe  phenomena, arifing from  folution by
 caloric,  are always lefs or more  conjoined with
 thofe which take place during folutions in water.
 We cannot pour water upon a fait,  on purpofe
 to diffolve  it,  without  employing a  compound
 folvent, both water and caloric.  Hence we may
 diftinguifh feveral different cafes of folution, ac-
 cording to the nature and mode of exiftence of
 each fait.   If,  for inftance,  a fait be difficultly
 foluble in water, and  readily  fo  by  caloric,  it
 evidently  follows,  that  this fait will  be fcantily
 foluble in cold water, and confiderably  in  hot
water;  fuch is nitrat of potafh, and  more efpe-
cially oxygenated muriat of  potafh.   If another
fait be little  foluble both  in  water and caloric,
the difference of its folubility in  cold and warm 
44*          ELEMENTS
  water will be very  inconfiderable:  fulphat  of
  lime is of this kind.  From thefe confiderations,
  it follows,  that there is a neceffary relation be-
  tween the following circumftances; the folubili-
  ty of a fait in cold water,  its  folubility in boil-
  ing  water, and the  degree of temperature  at
  which the fame fait liquefies by caloric, unaffifted
  by water ; and that the difference of folubility in
  hot and cold water is  fo much greater  in propor-
  tion to its ready folution in caloric, or  in propor-
  tion to its fufceptibility of liquefying in a low de-
  gree of temperature.
   The above is a general view of folution ; but,
 for want of particular facts, and fufficiently ex-
 act experiments, it is ftill  nothing more than an
 approximation towards a particular theory.   The
 means of completing this part of chemical fcience
 is extremely fimple.   We  have only to afcertain
 how much of each  fait is  diffolved by a certain
 quantity of water at different  degrees of  tem-
 perature : and  as,  by the  experiments publifh-
 ed by Mr de la Place  and  me, the quantity of
 caloric contained in a pound of  water at  each
 degree ofthe thermometer is accurately known,
 it will be very eafy  to  determine, by fimple ex-
 periments,  the proportion of water and caloric
 required for folution by each fait, what quanti-
 ty of caloric is abforbed by each at the moment
of liquefaction, and how much is difengaged at
 the moment of cryftallization.  Hence the reafon 
           OF  CHEMISTRY,      449

  why falts are more rapidly foluble in hot than
  in cold wafer, is perfedly evident.  In all  folu.
  tions of falts, caloric is employed.   When that
  is furnifhed intermediately from the furrounding
  bodies, it can only arrive  flowly  to the  fait j
  whereas this is greatly accelerated,  when the re-
  quifite caloric exiftsj ready combined with the
  Water of folution.
    In general the fpecific gravity of water Is aug,
  mented by  holding  falts in folution; but there
  are fome exceptions  to  the rule.  Some time
  hence, the quantities of radical, of oxygen, anc}
 of bafe,  which conftitute each  neutral fait,  the
 quantity of water and caloric neceffary for folu-
 tion, the increafed fpecific gravity communicated
 to water, and the figure of the elementary parti,
 cles of the cryftals, will all be accurately known.
 From thefe all the circumftances  and phenomena
 of chryftallization will be  explained: and  by
 thefe means this part of chemiftry will be com-
 pleted.   Mr Seguin has formed the plan  of a
 thorough inveftigation of this kind, which  he.
 is extremely capable of executing.
 ^ The folution of  falts in water requires no par-
 ticular apparatus;  fmall glafs phials of different
 fizes, PI. II. Fig. 16. and i7. pans  of earthen-
 ware, A, Fig. 1. and 2. long-necked matr&fles,
Fig. 14. and pans or bafons  of copper or of fiU
ver, Fig. 13. arui I5, anfvvc • very well for thefe
operations.
                    HI 
45°
ELEMENTS
              SECT.  II.


               Of Lixiviation.


  This is an  operation ufed  in  chemiftry  and
manufactures for feparating fubftances which are
foluble in water, from fuch as are infoluble. The
large vat or tub,  PI. 2. Fig.  12. having a hole
D near its  bottom, containing a wooden-fpigot
and foffet, or metallic ftop-cock DE, is generally
ufed for this purpofe.  A thin ftratum of ftraw
is placed at  the  bottom of the  tub : over this,
the fubftance to be lixiviated  is laid, and covefed
by a cloth : then hot or cold water, according to
the degree of folubility of the faline matter, is
poured on.   When the water is fuppofed to have
diffolved all the faline parts,  it is let off by the
ftop-cock : and,  as fome of the water charged
with fait neceffarily adheres to the ftraw and in-
foluble matters, feveral frefh  quantities of water
are  poured  on.   The  ftraw ferves to fecure a
proper paffage for the water, and may be  com-
pared to the ftraws or glafs  rods ufed in filtrat-
ing> to keep the paper from touching the fides
of the funnel.  The cloth, which is laid over the
 matters under lixivV'ion. prevents the water from 
OF  CHEMISTRY.
45i
 making a hollow in thefe fubftances where it is
 poured on, through which it might efcape with-
 out acting upon the whole mafs.
   This operation is lefs or more imitated in che-
 mical  experiments; but as in thefe,  efpedally
 with analytical views,  greater exactnefs  is re-
 quired, particular precautions muft be employed,
 fo as not to leave any faline or foluble part in the
 refiduum.   More water muft be employed than
 in ordinary lixiviations; and the fubftances ought
 to be previoufly ftirred up in the water, before
 the clear liquor is drawn off, otherwife the whole
 mafs might not be  equally lixiviated ;  and fome
 parts might  even efcape altogether from the ac-
 tion of the water.   We muft likewife employ
 frefh portions of water in confiderable quantity,
 until it comes off entirely free from fait, which
 we may afcertain by means of the hydrometer
formerly defcribed.
   In experiments with  fmall quantities, this ope-
ration  is conveniently performed in jugs or ma-
 traffesof glafs,and by filtrating the liquor through
paper in a glafs funnel.  When the fubftance is in
larger quantity, it may  be lixiviated  in a kettle
of boiling-water,and filtrated through paper, fup-
ported by cloth, in the wooden frame, PI. II.
 Fig. 3. and 4: and in operations in the large
 way, the tub already mentioned muft be ufed. 
\
452         ELEMENTS
               SECT.   III.


               Of Evaporation.


  This operation is ufed for feparating two fub-
ftances from each other, of which one at leaft
muft be fluid, and whofe degrees of volatility are
confiderably different.  By  this means we obtain
a fait,  which has been diffolved in water, in its
concrete form.  The water,  by  heating, becomes
combined with caloric, which renders it volatile;
while the particles of the  fait being  brought
nearer to each other, and within  the fphere  of
their mutual attraction, unite into the folid ftate.
   As it was long thought that the air had great
influence upon  the quantity of fluid evaporated,
it will  be proper to point out  the errors which
this opinion has produced.   There certainly is
a conftant flow evaporation from fluids  expofed
to the  free air :  and, though this  fpecies of eva-
poration may be confidered in fome degree as a
folution in air,  yet caloric  has confiderable  in-
fluence in producing it; as is evident from  the
refrigeration which always accompanies this pro-
cefs ;  hence we may confider  this gradual  eva-
poration as a compound folution, made  partly in 
OF  CHEMISTRY.
453
air, and partly in caloric.   But the evaporation
which takes place from a fluid kept continually
boiling, is quite different  in its nature:  and in
it the evaporation produced by the action of the
air is exceedingly inconfiderable in comparifon
with that which is occafioned by caloric.  This
latter fpecies may be termed vaporization rather
than evaporation.   This procefs is not accelerat-
ed in proportion  to the extent  of evaporating
furface, but in proportion to  'he  quantities of
caloric which combine with the fluid.   Too  free
a current of cold  air is often hurtful to this pro-
cefs ; as it tends to carry off caloric from the wa-
ter, and confequently retards its converfion into
vapour.   Hence  there is no inconvenience pro-
duced by covering,  in a certain degree, the  vef-
fels in which liquids are evaporated by continual
boiling, provided the covering body be of fuch
a nature as does not ftrongly draw  off  the calo-
ric, or, to ufe an expreffion cf Dr Franklin's,
provided it be a bad conductor of heat.   In  this
cafe,  the vapours efcape through fuch opening
as is  left;  and at  leaft as much is evaporated^
frequently more than when free accefs is allowed
to the external air.
   As, during evaporation, the fluid carried off by
caloric is entirely  loft,  being facrificed for  the
fake of the fixed  fubftances with which  it  was
combined, this procefs is only  employed, where
the fluid is of  fmall value, as water, for inftance. 
454
ELEMENTS
But, when the fluid is of more confequence, we
have recourfe to diftillation, in which procefs we
preferve both the fixed fubftance and the volatile
fluid.  The veffels employed for evaporation, are
bafons or pans of copper,  filver or lead, PI. II.
Fig. 13. and 15. or capfules of glafs, porcelain,
or ftone water, PI. II. A, Fig. 1. and 2. PI. III.
Fig. 3. and 4.  The beft  utenfils for  this  pur-
pofe are made  of the bottoms of glafs retorts and
matraffes; as their equal thinnefs renders them
more fit  than any other kind of glafs  veffel for
bearing  a brifk fire, and fudden alterations of
heat and cold, without breaking.
   As the method  of cutting thefe glafs veffels is
no where defcribed in books,  I fhall here give a
defcription of it, that they may be made by che-
mifts for themfelves out of fpoiled  retorts, ma-
traffes, and recipients, at a much  cheaper rate
than any which can be procured from glafs ma-
nufacturers. The inftrument, PI. III. Fig. 5. con-
fifting of an iron ring AC, fixed to  the rod AB,
having a  wooden handle D, is employed as fol-
lows : Make the ring red hot in the fire, and put
it upon the matrafs  G, Fig. 6. which is  to  be
cut. When the glafs is fufficiently heated, throw
on a little cold water ; and it will generally break
exactly at the circular line heated by the ring.
   Small flafks or phials of thin glafs are exceed-
 ing good veffels for evaporating fmall quantities
 of fluid.  They are very cheap, and ftand the fire 
OF  CHEMISTRY.
455
Temarkably.   One  or more of thefe  may  be
placed upon a fecond grate above the furnace,
PI. III. Fig. 2. where they will only experience
a gentle heat.   By this means, a great number
of experiments may be carried on at one time.
A glafs retort, placed in a fand-bath,  and co-
vered with a dome of baked earth, PI. III. Fig.
i. anfwers  pretty  well for evaporations.  But
in this way, it is always confiderably flower, and
is even liable to accidents.  As the fand heats
unequally, and the  glafs  cannot dilate in the
fame unequal manner, the retort is very liable
to break.   Sometimes the fand ferves exactly the
office of the iron ring formerly mentioned; for,
if a fingle drop of  vapour,  condenfed into  li-
quid,  happens to  fall upon the heated part  of
the veffel, it breaks circularly at that  place.
When a very  intenfe fire is neceffary, earthen
crucibles may be ufed—but we generally ufe the
word evaporation, to  exprefs what is produced  by
the temperature of boiling water, or not much
higher. 
4j6
ELEMENTS
               SECT.   IV.


               Of Cryfiallizatiom


   Jn this procefs, the integrant parts of a folio!
body,  feparated from each other by  the  inter-
vention of a fluid, are made to exert the mutual
attraction of aggregation,  fo as to  coalefce and
reproduce a folid mafs.  When the particles of
a  body are only  feparated by caloric,  and the
fubftance is thereby retained in the liquid ftate,
all that is neceffary for making it cryftallize, is
to remove a part  of the caloric which is lodged
between its particles, or, in other words, to cool
it.   If this  refrigeration be flow, and the body
be at the fame  time left at  reft,  its  particles af-
fume a  regular arrangement;  and cryftalliza-
tion, properly  fo called, takes  place.  But, if
the refrigeration be made rapidly,  or if the li-
quor be agitated at the moment of its paffage to
the  concrete ftate, the cryftallization is irregu-*
Jar and confufed.
   The fame phenomena occur with  watery folu-
tions, or  rather in thofe made partly in water,
and partly by caloric.   So long as there  remains
a fufficiency of water and  caloric" to keep the
particles of the  body afunder beyond the fphere 
           OF  CHE M ISTRY.      4j7

  of their mutual attraction,  the'fait  remains in
  the fluid fta:e.   Bat, whenever either caloric or
  water is not  prefent in fuaueient quantity, and
  iLe attraction of the particles for each other be-
  comes fuperior to the power which keeps thein
  afunJar, the fait recovers its concrete  form ; and
  the cryftal j produced are the more regular in pro-
  portion as the evaporation has been  flower and
  more tranquilly performed.
    All the phenomena  we formerly  mentioned
  as talcing place during the folution of faN, oc-
  cur in a contrary feme, during the cryftallyza-
  tion.   Caloric is  difengaged at  the  halant of
  their a^iunun- the  folid ftate, which furnishes
 an  additional  proof of fait  b.ao- held in folu-
 tion  by the  compound  action of"water and ca-
 loric.  Hence, to caufe falts to cryftallize, v,rXh
 readily ]iq^fy  by means of caloric, it is not fuf-
 ficient to  carry off the water which held  th-n
 m folution, but the  caloric united to them nrt
 likewife be removed.  Nitrat of potafh, ope-
 rated muriat of potafli, alum, fulphat of  foda
 &c. are examples  of tliis circumftance; as  to
make thefe falts cryftalize, refrigeration  r-u:
oe adJed  to  evaporation.   Such falts, on the
contrary,  as require  little caloric for bei^  kept
m folutmn, and which,  from that circurri,nce
"e almoft equally foluble in cold and warm wa!
ter, are cryftallizable  by  fimp'y  caraviu- off
the  water  which holds them  in folution ;°and
                  M m m 
458
ELEMENTS
   even  recover their folid ftate in boiling wat*r ;
   fuch  are fulphat of lime, muriat of potafli and
   of foda, and feveral others.
     The art of refining  faltpetre depends  upon
   thefe  properties of falts, and upon their different
   degrees of folubility in hot and cold water.  This
   fait, as" produced in the manufactories  by the
   firit operation, is  compofed of many different
   falts.  Some are deliquefcent, and not fufceptible
   of being cryftalized,  fuch as the nitrat and mu-
   riat of lime.  Others are almoft equally" foluble
   in hot and cold water ;  as the muriats of potalh
   and of foda.  And laftly, the faltpetre, or  nitrat
   of potafh, is  greatly more foluble in hot than it
   is in  cold water.  The operation is begun by
   pouring upon this mixture of falts as much wa-
   ter as will hold even the leaft foluble,  the mu-
   riats of foda and of potafli, in folution.   So long
   as it is hot, this  quantity  readily diffolves  all the
   faltpetre : but upon cooling, the greater part of
   this fait cryftalizes,  leaving  about a fixth part
   remaining diffolved,  and mixed  with the nitrat
   of  lime and the two muriats.   The nitre obtain-
   ed  by this procefs is flill fomewhat impregnated
   with  other falts, becaufe it  has been cryflallized
   from water  in which thefe abound:  It is com-
   pletely purified from thefe by a fecond folution
   in  a  fmall quantity of  boiling water and fecond
   cryftallization.  The water remaining after thefe
#if cryat. libations of nitre, is ftill loaded with a mix- 
          OF  CHEMISTRY.        459

 ture of faltpetre, and other falts.  By farther eva-
 poratien, crude faltpetre, or rough-petre, as the
 workmen call it, is procured from  it:  and this
 is purified by two frefh folutions  and cryftalliza-
 tions.
   The deliquefeent earthy  falts, which do  not
 contain the nitric acid, are rejected in this  ma-
 nufacture.   But thofe which confift of that acid
 neutralized by  an earthy bafe, are diffolved in
 water, the earth is precipitated by means of pot-
 afh, and allowed to fubfide ; the clear liquor is
 then decanted, evaporated, and allowed  to cryf-
 tallize.  The above management  for  refining
 faltpetre, may ferve as a general rule  for Sepa-
 rating  falts  from  each other, wl:ich iiappen to
 be  mixed together.  The  nature of each muft
 be confidered, the proportion in which each dif-
 folves in given quantities  of water,  and  the  dif-
 ferent folubility of each in hot  and  cold water.
 If to thefe we add the property which fome falts
 poffefs, of being  foluble in alhohol,   or in a mix-
 ture of  alkohol and  water,  we have  many re-
fources for feparating falts  from  each  other  by
 means  of cryftallization; thou ;h  it   mull be al-
 lowed, that it is extremely difficult to render this
 feparation perfectly complete.
  The veffels ufed for  cryftallization, are pans
 of earthen ware, A, PL II. I i-.  1.  and 2.  and
 large flat dimes, Pi. III. Firr. 7.   When  a faiine
folution is to be expofed to a flow  evaporation «* 
460
ELEMENTS
in the heat of the atmofphere, with free accefs of
air, veffels of fome depth,  PI. III. rig. 3. muft
be employed, that there  may be a confiderable
body of licuid.   By this means, the cryftals pro-
duced are cf confiderable fize, and remarkably
regular in their figure.
   Every fpecies of fait cryftallizes in a peculiar
form, and even each fait varies  in the form of
its crynals,  according to circumftances, which
take place during cryftallization.   We muft not
from thence conclude that  the faline particles of
each fpecies  are indeterminate in their figures:
The primitive  particles of all bodies, efpecially
of falts,  are perfectly conftant in  their fpecific
forms.   But the cryftals which form in our ex-
periments, are compofed of congeries of minute
particles, which,  though perfectly equal in fize
and fhape, may affume very difiimilar arrange-
ments, and confequently produce a vaft variety
of regular forms, which have not  the fmalleft
apparent refemblance to each other, nor to the
original  cryftal.  This fubject has been very ably
treated  by the Abbe Hairy, in feveral memoirs
prefented to  the Academy, and in his  work up-
on the fl.ructure of cryftals.  It is only neceffary
to extend generally to the clafs of falts the princi-
ples he  has particularly applied to fome cryftal-
lized ftones. 
J
OF  CHEMISTR Y.     461
             SECT.      V


             Of fimple Diftillation.

  As diftillation has  two diftinct objects to ac-
complifli, it  is diviiible  into  fimple and com-
pound : and, in this fection, I mca; to  confine
myfelf entirely to the former.   When two bo-
dies, of which one is more volatile than the
other, or has  more  affinity to caloric, are fub-
mitted to  diftillation, our  intention is  to fepa-
rate them from each other.   The more volatile
fubftance affumes the form of gas ; and is after-
wards condenfed  by refrigeration in proper vef-
fels.   In this cafe, diftillation, like evaporation,
becomes a fpecies of mechanical operation, which
feparates two fubftances from each other, without
decompofing  or altering the nature of either.  In
evaporation, our only  object is  to  preferve  the
fixed  body, without paying any regard  to  the
volatile matter ; whereas, in diftillation, our prin-
cipal  attention is generally paid to the  volatile
fubftance, unlefs when we intend to preferve both
the one and the other.   Hence, fimple  diftilla-
tion is nothing more than evaporation produc d
in clofe veffels.
  ^he moft fimple diftilling veffel  is a  f. ccic> 
4-62
ELEMENTS
    of bottle or matrafs, A, PI. IN. fig. 8. which has
    been bent from its original form EC to LI), and
    which is  then called a retort. When  ufed, it  is
    placed either in a reverberatory furnace, PI. XIII.
    fig.  2. or in a fand bath, under a dome of baked
    earth, PI. III. Fig. i.  ' To receive  and condenfe
    the products, we  adapt  a  recipient, E.  PI. III.
    9. which is luted to the retort.
      Sometimes, more efpecially in pharmaceutical
    operations, the  glafs or ftone ware cucurbit, A,
    with its capital B, PI. III. Fig.  12. or the glafs
    alembic  and capital,  Fig. 13. of  one  piece,  is
    employed.   This  latter is managed by  means of
    a  tubulated  opening  T, fitted  with a ground
    ftopper of cryftal.   The capital, both of the cu-
    curbit and alembic, has a furrow or trench, r, r,
    intended  for  conveying  the condenfed  liquor
    into  the beak RS, by  which it runs out.  As,
    in almoft  all diftillations, expanfive vapours are
   produced, which might burft the veffels employ-
    ed, we are under the  neceflity of having  a fmall
    hole, T,  Fig.  9.  in  the balloon  or  recipient,
   through which thefe may find vent.  Hence, in
   this way  of dlflilling, all the products which are
    permanently aeriform, are entirely loft:  and even
   fuch  as difficultly lofe thatftate, have not fufficient
   fpace to condenfe in the balloon.   This appara-
    tus is not, therefore, proper for  experiments of
   inveftigation ; and can only be admitted in the
*  ordinary   operations  of the  laboratory   or in 
OF  CHEMISTRY.
463
 pharmacy.   In the article appropriated for com-
 pound diftillation,  I fhall  explain  the various
 methods which have been contrived for preser-
 ving the whole products from bodies in this pro-
 cess.
   As  glafs  or earthen veffels are very brittle,
 and do not  readily bear  fudden alterations of
 heat and cold, every well regulated  laboratory
 ought  to  have one  or  more  alembics of  metal
 for  diililling water, fpiritous liquors,  effential
 oils, £:c.  This apparatus  confifts of a cucurbit
 and capital of tinned  copper or brafs, PI. III.
 Fig. 15. and  16. which, when judged  proper,
 may be placed in  the water bath, D, Fig. 17.
 In diftillations, efpecially of fpiritous liquors, the
 capital muft be  furniflied  with a refrigeratory,
 SS, Fig". 16. kept continually filled  with cold
 water.   When the  water  becomes heated, it is
 let off by the ftop-cock,  R,  and renewed with a
 frefh fupply  of cold water.  As  the fluid diftil-
 led is   converted into gas  by means of caloric
 furniflied  by the fire of the  furnace, it  is evi-
 dent,  that it  could not  condenfe, and, confe-
 quently, that no  diftillation, properly fpeakincr
 could take place, unlefs it be made to depofit in
 the capital all the caloric it received  in the cu-
 curbit.   With this view, the fides ofthe capital
mult always be preferved at  a  lower tempera-
ture than is  neceffary for keeoin^ the diuniino-
fubftance in the ftate cf gas; and the water  in 
464
ELEMENTS
    the  refrigeratory  is  intended for  this purpoff.
   Water is converted into gas by the  temperature
   of 2120 ; alkohol by  182.750 ;  and  ether  by
    1040.  Hence thefe  fubftances cannot be diftil-
   led, or rather, they  will fly off in the ftate of gar,
   unlefs the temperature of the refrigeratory  be
   kept under there respective degrees.
      In the diftillation  of fpiritous and other ere-
   panfive liquors, the above dff bribed refrigerato-
   ry is not fufficient for condenfing all the vapours
    which arife.  In this cafe, therefore, inftead  of
    receiving the  diftilled liquor immediately from
    the  beak  TU, of  the capital into a recipient,
    a worm is  interpofed between  them.  This in-
    ftrument is reprefented PI. III. Figi 18, contain-
    ed in a worm tub of tinned copper.  It confiih
    of a metallic tube bent into a con fde-able num-
    ber of fpiral revolutions.  The veffel, which con-
    tains the worm, is  kept full of cold water, which
    is renewed as it grows warm.  This contrivance
    is employed  in all diflllleries of fpirits, without
    the intervention of  a capital and  refrigeratory,
    properly fo called.   The one reprefented in the
    plate is furniflied with two worms, one cf them
    being particularly appropriated to diftillations of
    odoriferous fubftance;.
      In  fome fimple disinflations, it is neceffary to
    interpofe an  adopter between the retort  and re-
    ceiver,  as  fhewn  PI.  TIL Fig. 11.  This  may
*   ferve two different purpofes ', thh-r to feparate 
         OF  CHEMISTRY.     4G5

two products of different degrees of volatility;
or to remove the receiver to a greater  diftance
from the furnace,  that it may  be lefs  headed.
But thefe, and feveral other more complicated
inftruments of ancient contrivance, are far from
producing the accuracy requifite in modern che-
miftry, as will be readily perceived, when I come
to treat of compound diftillation.


               SECT.   VI.

               Of Sublimation.

  This  term is applied to the diftillation of fub-
ftances which condenfe in  a  concrete  or  folid
form, fuch as the fublimation of fulphur, and of
muriat of ammoniac, or  fal ammoniac.  Thefe
operations may  be conveniently  performed  in
the ordinary diftilling veffels already  defcribed,
though, in the  fublimation of fulphur, a fpe-
cies of veffels, named alludels, have  been  ufu-
ally employed.  Thefe are veffels of ftone  or
porcelain ware,  which adjuft to each other over
a cucurbit, containing the fulphur to  be fublim-
ed.   One of the beft fubliming veffels, for fub-
ftances which arc not very  volatile, is  a flafk,
or phial of glafs, funk about two  thirds into a
                   N n n 
A(56         ELEMENTS

fand bath; but in this way we are apt to lofe a
part of the produfts.   When thefe are wifhed
to be entirely preferved, we muft have recourfe
to the pneumato-chemical  diftilling  apparatus,
to be defcribed in the following chapter. 
OF  CHEMISTRY.     467
               CHAP.  VI.

Of Pneumato-chemical Diftillations, Metallic Dif
  folutions, and fome other Operations which re-
  quire very Complicated Inftruments..
                SECT.  I.

 Of Compound and Pneumato-chemical Diflillations.

   IN the preceding chapter, I have only treated
    of diftillation as a fimple operation, by which
 two fubftances, differing in their degrees of vola-
 tility, may  be feparated from  each other;  but
 diftillation often a&ually decompofes thefubftan^
 ces fubmitted to  its action, and  becomes one of
 the moft complicated operations in chemiftry.
 In every diftillation, the fubftance diftilled muft
 be brought to the ftate of gas, in the cucurbit or
 retort, by combination with caloric :  In fimple
 diftillation, this caloric is given out in  the re-
 frigeratory or in the worm, and  the  fubftance
 again recovers its liquid or folid form;  but the
fubftances fubmitted to  compound diftillation 
468
ELEMENTS
are abfolutely decompounded ;  one part, as for
inftance, the carbon they contain, remains fixed
in the retort,  and all the reft of the elements
are reduced to gaffes of different kinds.   Some
of thefe gaffes are fufceptible of being condenf-
ed, and of recovering their folid or liquid forms,
while others are permanently aeriform ; one part
of thefe are abforbable by water, fome by the al-
kalies, and others are not fufceptible  of being ■
abforbed at all.   An ordinary diftiliing  appara-
tus, fuch as has been defcribed in the preceding
chapter,  is quite  infufficient for retaining or for
feparating thefe diverfified products, and we are
obliged to have recourfe, for this purpofe, to me-
thods of a more  complicated nature.
  The apparatus  I am  about to defcribe is cal-
culated for the moft complicated diftillations, and
may be Amplified or extended according to cir-
cumftances. It confifts  of a tubulated glafs retort
A,  PI. IV. Fig', i. having its  beak fitted to a
t .bulated balloon or recipient BC ; to the upper
orifice D of the balloon a bent tube T)Efg is ad-
justed, which, at  its other extremity g, is plun-
ged into  the liquor contained in  the bottle  L,
with  three  necks  xxx.   Three  other  fimilar
bottles are  connected   with this firft  one, by
means of three fimilar bent tubes  difpofed  in
the fame manner  ;  and the fartheft  neck of the
laft bottle is connected with a jar in a pnetima-
10-chcinical apparatus, by  means  of  a bent 
OF  CHEMISTRY.      469
 tube *.   A determinate weight of diftilled water
 is ufually put into the firft bottle, and the other
 three have each a folution of  cauftic potafh  in
 water.  The weight of all  thefe bottles, and of
 the water and alkaline folution they contain,muft
 ]be accurately  afcertained.  Every thing being
 thus  difpofed, the junctures between the retort
 and recipient, and of the tube D of the  latter,
 muft be luted with fat lute, covered  over with
 flips  of linen,  fpread with  lime and  white  of
 egg;  all the other junctures are to be fecured by
 a lute made of wax and rofin melted together.
   When all thefe  difpofitions are  completed,
 and when, by means of heat applied  to the re-
 tort  A,  the fubftance  it  contains becomes de-
 compofed, it is evident  that  the leaft volatile
 products muft condenfe or fublime in the beak
 or neck of the retort itfelf,  where moft  of the
 concrete fubftances  will  fix themfelves.  The
 more volatile fubftances, as the lighter oils, am-
 moniac, and feveral others, will condenfe in the
 recipient GC, whilft the gaffes, which are  not
fufceptible of condenfation by cold, will pafs on
by the tubes, and  boil up through the liquors
in the feveral bottles.   Such as are  abforbable

  * The representation of this  apparatus, PI. IV. Fig. I.
will convey a much better idea of its difpofition than can
 poffibly be given by the moft laboured defcription.—T. 
479
ELEMENTS
by water will  remain in the firft bottle, and
thofe which cauftic alkali can abforb will re-
main in the others ; while  fuch  gaffes  as are
not fufceptible of abforption, either by water or
alkalies, will efcape by the tube RM, at the end
of which they may be  received into jars in a
pneumato-chemical apparatus.   The carbon and
fixed earth, &c« which form the fubftance or re-
fiduum, anciently called  caput mortuum,  remain
behind in the retort.
   In this manner ©f operating, we have always
 a very  material  proof of the  accuracy of the
 analyfis, as the whole weights of the products
 taken  together,   after the  procefs is  finifhed,
' muft be exactly equal to the weight .of the ori-
 ginal fubftance fubmitted to diftillation.  Hence,
 for inftance,  if  we have operated upon eight
 ounces of ftarch or gum arabic,  the weight  of
 the charry refiduum in the retort, together with
 that of all the products gathered in its neck and
 the balloon, and of all the gas received  into the
 jars by the tube RM  added to  the additional
 weight acquired by the bottles, muft, when  ta-
 ken together, be exactly eight ounces.   If the
 product be lefs or more, it proceeds from  er-
 ror, and the experiment muft be repeated until
 a fatisfactory refult be procured, which  ought
 not to  differ more than fix or eight grains  in the
 pound from the weight  of the fubftance fubmit-
 ted to  experiment. 
         OF  CHEMISTRY.     471

   In experiments of this kind, I for a long time
met with  an almoft infurmountable difficulty,
which  muft at laft have  obliged me to defift  al-
together, but for a very  fimple method of avoid-
ing it,  pointed out to me by Mr HaffenfTatz.
The fmalleft diminution in the heat of the fur-
nace, and many other circumftances infeparable
from this kind of experiments, caufe frequent
reabforptions of gas ;  when this occurs, the wa-
ter in the ciftern of the pneumato-chemical ap-
paratus rufhes into the laft  bottle  through the
tube RM; the fame circumftance happens from
one bottle into another, and the fluid is often
forced  even into the recipient C.   This accident
is prevented by ufing bottles having three necks,
as reprefented in the plate,  into one of which,
in each bottle, a capillary glafs-tube St, st,st,st,
is adapted, fo as to have its lower extremity / im-
merforl in the liquor.  If any abforption  takes
place, either in the retort, or in any of the bot-
tles, a  fufficient quantity of external air enters,
by means of thefe tubes, to fill up the void ; and
we get  rid of the  inconvenience at the price of
having  a fmall portion of common air  mixed
with the products  of the experiment, which  is
thereby prevented from failing altogether.  Tho*
thefe tubes admit  the external air,  they cannot
permit  any of  the gaffeous fubftances to efcape,
as they are always fhut below  by the water  of
the bottles. 
472
ELEMENTS
  It is evident,  that, in the courfe of experi-
ments with this apparatus, the liquor of the bot-
tles muft rife in thefe tubes in proportion  to the
preffure fuftained by  the gas  or air contained in
the bottles; and this preffure is determined by
the height and gravity of the column  of fluid
contained in all the fubfequent  bottles.   If we
fuppofe that each bottle contains three inches of
fluid, and that there are three inches of  water
in the ciftern of the  connected apparatus above
the orifice of the tube RM,  and allowing  the
gravity of the fluids  to be only  equal to that of
water, it  follows that the air in the firft bottle
muft fuftain a preffure equal to  twelve  inches
of water ;  the water muft therefore rife twelve
inches in the tube S, connected  with  the  firft
bottle, nine  inches in that belonging to  the fe-
cond, fix inches in the third, and three  in the
laft ; wherefore thefe tubes muft be  made fome-
what more than twelve,  nine,  fix, and three
inches long refpectively, allowance  being made
for  ofcillatory motions, which often take place
in the liquids.   It is fometimes neceffary to  in-
troduce a fimilar tube between  the retort  and
recipient;  and  as the  tube is not immerfed in
fluid at its lower extremity, until fome has col-
lected in the progrefs of the diftillation,  its up-
per  end muft be fhut at firft with a little lute, fo
as to be opened according to neceffity, or after 
OF  CHEMISTRY.
473
 there is fufficient liquid in the recipient to fe-
 cure its lower extremity.
    This apparatus cannot be ufed in  verv accu-
 rate experiments,  when the fubftances intended
 to be operated upon have  a very rapid action
 upon  each other,  or  when one of  them can
 only be introduced in fmall fucceflive portions,
 as in fuch as produce violent effervefcence when
 mixed together.  In  fuch cafes  we  employ a
 tubulated retort A, PI. VII. Fig. i. into which
 one of the fubftances  is introduced,  preferring
 always the folid body, if any fuch is to be treat-
 ed.  We then lute to the opening of the retort
 a  bent tube BCDA, terminating at its upper ex-
 tremity B in a funnel, and at its other end A in
 a  capillary opening. The fluid material of the
 experiment is poured into the  retort  by means
 of this funnel,  which muft be  made  of fuch  a
 length, from B to C, that the column of liquid
 introduced may counterbalance the  refiftance
 produced  by the liquors contained in all the bot-
 tles, PI. IV. Fig. i.
   1 hofe,  who have not been accuftomed to ufe
 the  above defcribed diftilling apparatus, may
 perhaps be ftartled at the great number of open-
 ings which require luting, and the time necef-
 fary for making all the  previous preparations in
 experiments of this kind.  It is very true, that,
 if  we take into account all the  neceffary weigh-
ings of materials and products, both before and
                   Ooo 
474
ELEMENTS
after the experiments, thefe preparatory and fuc-
ceeding fteps require much more time and atten-
tion than the experiment itfelf.  But, when the
experiment fucceeds properly,  we are well re-
warded for all  the time and trouble  beftowed,
as,  by one procefs carried on  in  this accurate
manner, much more juft and  extenfive  know-
ledge is acquired, of the nature of the vegetable
or animal fubftance thus fubmitted to inveftiga-
tion, than by many weeks afliduous labour in
the ordinary method of proceeding.
   When in want of bottles with  three orifices,
thofe with two may be ufed.   It is even  poffible
to  introduce all the three tubes at one opening,
fo  as to employ ordinary wide-mouthed bottles,
provided the  opening be fufficiently large.  In
this cafe we muft carefully fit the bottles  with
 corks very accurately cut,  and boiled in a mix-
 ture of oil, wax, and turpentine. Thefe  corks
 are pierced with the  neceffary holes for receiv-
 ing the tubes, by means of a  round file, as in
 PI. IV. Fig. 8. 
OF  CHEMISTRY.
475
               SECT.  II.

            Of Metallic Diffolutions.

   I have already pointed out the difference be-
 tween folution of falts in water and metallic dif-
 folutions.  The former requires no particular
 veffels ; whereas the latter require very compli-
 cated veffels of late invention, that we may not
 lofe any of the products of the experiment, and
 may therefore procure  truly conclufive refults
 of the phenomena which  occur.   The metals,
 in general, diffolve in acids with effervefcence,
 which is only a motion excited in the folvent by
 the difengagement of a great  number of bub-
 bles of air or aeriform fluid, which proceed from
 the furface of the metal, and break at the furface
 of the liquid,
  Mr Cavendifh and Dr Prieftley were the firft
 inventors  of a  proper apparatus for collecting
 thefe elaftic fluids.   That  of Dr Prieftley is ex-
 tremely  fimple,  and confifts of a bottle A, PI.
 VII. Fig. 2. with its cork B, through which paf-
 fes the bent glafs tube  BC, which is engaged
under a  jar filled with water in the pneumato-
 chemical apparatus, or fimply in a bafon full of
 water.  The metal is  firft introduced into the 
476
ELEMENTS
bottle ;  the acid is then poured over it;  and the
bottle is inftantly clofed with its cork and tube,
as reprefented in the plate.  But this apparatus
has its inconveniences.  When the acid is much
concentrated, or the metal much divided, the ef-
fervefcence begins before we have time  to cork
the bottle  properly ;  and fome gas efcapes, by
which we are  prevented from afcertaining  the
quantity difengaged with rigorous exactnefs. In
the next place, when we are obliged to employ
heat, or when heat is produced by the procefs,
a part of the acid diftils, and mixes with the wa-
ter of  the pneumato-chemical  apparatus, by
which  means we are deceived in our  calcula-
tion of  the quantity of acid  decompofed.   Be-
fides thefe, the water  in the  ciftern of the appa-
ratus abforbs all the gas produced, which is fuf-
ceptible of abforption, and renders it impoflible
to collect thefe without lofs.
   To remedy thefe  inconveniences, I  at  firft
ufed a bottle with two necks, PL VII. Fig. 3. in-
to one of which the glafs funnel BC is luted fo
as to prevent any air  efcaping.  A glafs rod DE
is fitted with emery to the funnel, fo as to ferve
the purpofe of a ftopper.   When it is ufed, the
matter  to be diffolved is firft introduced into the
bottle ;  and the acid  is  then permitted to pafs in
as flowly as we pleafe, by raifing the glafs .rod
gently as often as is neceffary until faturation is
produced. 
OF  CHEMISTRY.
477
    Another method has been fince employed,
  which ferves the fame  purpofe,  and is prefer-
  able to the laft defcribed in fome inftances. This
  confifts in adapting to one of the  mouths, of the
  bottle  A, PI. VII. Fig. 4.  a  bent  tube DEFG,
  having a capillary opening at D, and ending in,
  a funnel at G.   This tube  is fecurely luted to
  the mouth C of the bottle.   When any liquid is
  poured into the funnel, it  falls down to F ; and,
  if a fufficient quantity be  added, it paffes by the
  curvature E, and falls flowly into  the bottle, fo
  long as frefh liquor is fupplied at  the funnel.
 The liquor  can never be forced out of the tube,
 and no gas  can efcape through it, becaufe the
 weight of the liquid ferves the purpofe of an ac-
 curate cork.
   To prevent any diftillation of acid, efpecially
 in diffolutions accompanied with heat, this  tube
 is adapted to the retort A,  PI. VII. Fig. 1. and
 a fmall tubulated recipient,  M, is applied,  in
 which any liquor which may  diftil is condenfed.
 On  purpofe  to feparate any  gas that is abforb-
 able by  water, we  add the double-necked  bot-
 tle L, half filled with a folution of cauftic pot-
 afli ; the alkali abforbs any carbonic acid  gas,
 and ufually only one or two  other  gaffes  pafs
 into the jar of the connected  pneumato-chemi-
 cal apparatus through  the tube NO.   In the
firft chapter  of this third part, we have directed
how thefe are to  be fenarated  and  examined. 
473
E  L E M ENTS
If one bottle of alkaline folution be not thought
fufficient, two,  three, or more, may be added.


               SECT.  III.

Apparatus neceffary in  Experiments upon Vinous
        and Putrefaclive Fermentations.

   For thefe operations  a peculiar  apparatus,
efpecially intended for  this kind  of experiment,
is requifite.   The one I am about to defcribe, is
finally adopted, as the beft  calculated for the
purpofe, after numerous corrections and improve-
ments.   It confifts of  a large matrafs A, PI. X.
Fig. i. holding about twelve pints, with a cap of
brafs, a, b, ftrongly cemented to its mouth, and
into which is fcrewed  a bent tube c d, furniflied
with a ftop-cock  e.  To this tube is joined the
glafs recipient B, having three openings, one of
which communicates with the bottle  C, placed
below it.  To  the pofterior opening of this  re^
 cipient is fitted a glafs tube g h i,  cemented at g
and * to collets of brafs, and intended to contain
a very deliquefcent  concrete  neutral fait, fuch
as nitrat or muriat of lime, acetite of potafh, &c.
 This tube communicates with two  bottles D
 and E, filled to x and  y with a folution of cauftic
 potafh. 
OF  CHEMISTRY.     479
  All the parts of this machine are joined toge-
ther by accurate  fcrews: and the touching parts
have greafed leather interpofed, to prevent any
paffage of air.   Each piece is likewife furniflied
with two ftop^cocks, .by which its two extremi-
ties may be clofed; fo that we  can weigh each
feparately at any period of the operation.
   The fermentable matter, fuch as fugar, with
a proper quantity of yeaft, and diluted with wa-
ter, is put into the matrafs.   Sometimes, when
the fermentation  is  too rapid, a  confiderable
quantity of froth is produced,  which not only
fills the neck of the matrafs,  but paffes into the
 recipient,  and from thence runs down into the
 bottle C.  On purpofe to collect this fcum and
 muft, and to prevent it from reaching the tube
 filled with deliquefcent falts, the recipient and
 connected bottle are made of confiderable capa-
 city.
    In the  vinous  fermentation, only carbonic
 acid gas is difengaged, carrying with it a fmall
 proportion of water in folution.   A great part
 of this  water is depofited in paffing through the
  tube g h i, which  is  filled  with  a  deliquefcent
  fait  in grofs powder: and the quantity is afcer-
  tained by  the augmentation of the weight of the
  fait. The carbonic acid gas bubbles up through
  the alkaline folution in the bottle  D, to which
  it is conveyed by the tube  k  I m.   Any  fmall
  portion which may not be  abforbed  by this 
480        ELEMENTS
firft  bottle, is fecured by the folution in the fe-
cond bottle E ; fo that nothing, in general, paf-
fes into the jar F, except the common air con-
tained in the veffels at the commencement of the
experiment.
  The fame apparatus  anfwers extremely well
for experiments upon  the putrefactive fermen-
tation: but, in this cafe a confiderable quantity
of hydrogen gas is difengaged through the tube
q r s t u, by which it is conveyed into the jar F ;
and, as  this difengagement is very rapid, efpe-
cially in  fummer, the jar  muft  be  frequently
changed.  Thefe putrefactive fermentations re-
quire  conftarit attendance from the above cir-
cumftance : whereas the  vinous  fermentation
hardly needs any.  By means of this apparatus,
 we  can afcertain,  with  great  precifion,  the
 weights of the fubftances fubmitted to ferment-
 ation, and of  the liquid and aeriform products
 which are difengaged.   What has been already
 faid, in Part I. Chap. XIII. upon the products of
 the vinous fermentation, may be confulted. 
OF  CHEMISTRY.      481
               SECT.   IV.


   Apparatus for the Decompofition of Water.

  Having already given an account, in the firft
part of this work,  of  the experiments  relative
to the decompofition of water, I fhall avoid any
unneceffary  repetitions, and  only give a few
fummary obfervations  upon the fubject in this
fection.   The  principal fubftances which have
the power of decompofing water, are iron and
charcoal; for  which  purpofe they require  to
be made red hot, otherwife the water is only re-
duced into vapour, and condenfes afterwards by .
refrigeration, without fuftaining the fmalleft al-
teration.   In a red heat, on the contrary, iron or
charcoal carry off the oxygen  from its  union
with hydrogen; in the firft cafe, black oxyd of
iron is produced, and the hydrogen is difengaged
pure in form of gas;  in the other cafe, carbo-
nic acid gas is formed, which difengages, mix-
ed with  the hydrogen gas,  and this  latter is
commonly carbonated, or holds  carbon in folu-
tion.
   A mufket-barrel, without its breach pin, an-
fwers exceedingly  well for the decompofition of
water, by means  of  iron, and one fhould  be
                    pPP 
4-8z
ELEMENTS
chofen of confiderable length, and pretty ftrong.
'When too fhort, fo as to run the rifle of heating
the  lute too much, a tube of copper muft be
ftrongly foldered to one  end.   The  barrel is
placed in a long furnace CDEF, PI.  VII.  Fig.
 n. fo as to have a  few  degrees  of inclination
from E to F;  a glafs retort A,  is luted to  the
upper extremity E, which contains water, and
is placed upon the furnace VVXX.  The lower
extremity F is luted to a  worm SS,  which is
 connected with the tubulated bottle H, in which
any water diftilled without decompofition, dur-
ing the operation, collects, and the difengaged
 gas is carried by the tube KK to jars in a pneu-
 mato-chemical  apparatus.   Inftead of the re-
 tort, a  funnel  may  be  employed, having its
 lower part fhut by a ftop-cock, through which
 the water is allowed to drop gradually into the
 gun-barrel.   Immediately  upon  getting into
 contact with the heated part of the  iron, the
 water is converted into fleam, and the experi-
 ment proceeds in the fame manner as if it were
 furniflied in vapours from the retort.
   In the experiment made by Mr Meufnier and
 nie before a committee of the Academy, we ufed
 every precaution to obtain the  greateft poffible
 precifion in the refult of our experiment, having
 even exhaufted ail the veffels employed beforewe
 began, fo that the hydrogen gas obtained might
 be free from any mixture of azotic gas. The re- 
OF  CHEMISTRY.     483
fulte of that experiment will hereafter be given
at large in a particular memoir.
  In numerous  experiments we are obliged to
ufe  tubes of glafs, porcelain or copper, inftead
of gun-barrels;  but  glafs has the difadvantage
of being  eafily melted and flattened, if the heat
be in  the fmalleft degree raifed too high; and
porcelain is moftly full of fmall  minute pores,
through which the gas efcapes, efpecially when
compreffed  by a column of water.   For thefe
reafons I  procured a tube of brafs, which Mr
de la Briche got  call and bored out of the folid
for me at Strafburg, under his  own inflection.
This tube is extremely convenient for decompof-
ing alkohol, which refolves into carbon, carbo-
nic acid  gas, and hydrogen gas j it may likewife
be  ufed with the fame advantage for decompof-
ing water by means of  charcoal, and in  a great
number of experiments of this nature. 
434        ELEMENTS
              CHAP.   VII.


  Of the Compofition and Application  of Lutes.


    THE neceffity of properly fecuring the junc-
     tures of chemical veffels, to  prevent the
efcape  of any of the products of experiments,
muft be fufficiently apparent; for this  purpofe
lutes are employed, which ought to be of fuch a
nature as to be equally impenetrable to the moft
fubtile fubftances, as glafs itfelf, through which
only caloric can efcape.
  This firft object of lutes is very well accom-
plifhed by bees wax, melted with about an eighth
part of turpentine.  This lute is very eafily ma-
naged, flicks very clofely to  glafs,  and is very
difficultly penetrable; it may be rendered more
confiftent,  and lefs or more  hard or pliable, by
adding different  kinds of refinous matters.  Tho*
this fpecies of lute anfwers  extremely  well  for
retaining gaffes and vapours, there are many che-
mical experiments which  produce confiderable
heat, by which  this lute becomes liquefied, and
confequently the expanfive vapours muft very
readily force through and efcape. 
OF  CHEMISTRY.
4^
  For fuch cafes, the following fat lute is  the
beft hitherto difcovered, though not without its
difadvantages, which fhall be pointed out. Take
very pure and dry unbaked clay,  reduced to a
fine powder ; put this into a brafs mortar ; and
beat it, for feveral hours,  with a heavy iron pef-
tle, dropping in flowly fome boiled lintfeed oil.
i: is is oil which has been oxygenated, and has
acquired a drying quality, by being boiled with
litharge.  This lute is more tenacious, and ap-
plies better, if amber varnifli be ufed inftead of
the above oil.   To make this varnifh, melt fome
yellow  amber  in an iron  ladle, by which ope-
ration it lofes a part of its fuccinic acid, and ef-
 fential oil; and mix it with lintfeed oil.  Though
the  lute  prepared with  this varnifli,  is  better
than that made with boiled oil, yet, as its addi-
 tional expence is hardly compenfated by  its fu-
 perior quality,  it is feldom ufed.
   The  above fat lute is capable  of fuftaining  a
 very violent degree of heat; is impenetrable by
 acids  and fpiritous liquors ; and adheres  ex-
 ceedingly well to metals,  ftone ware, or  glafs,
 provided they have been previoufly rendered
 perfectly dry.   But if, unfortunately, any ofthe
 liquor in the courfe of an experiment gets thro',
 either between the  glafs  and  the lute,  or  be-
 tween  the layers  of the lute  itfelf,  fo  as to
 moiften the part, it is extremely difficult to clofe 
486         ELEMENTS

the opening.  This is the chief inconvenience
which attends the ufe of fat lute, and  perhaps
the only one it is fubject to.  As it is apt to fof-
ten by heat, we muft furround all the junctures
with flips of wet bladder, applied over the lut-
ing, and fixed on by pack-thread tied round both
above and below the joint. The bladder, and con-
fequently the lute below, muft be farther fecur-
ed by a number of turns of pack-thread all over
it.  By thefe precautions, we are free from every
danger of accident; and the junctures fecured
in this  manner may be  confidered,  in experi-
ments, as hermetically fealed.
   It  frequently happens that the figure of the
junctures prevents the application  of ligatures,
which is the cafe with the three-necked bottles
formerly defcribed : and it even requires  great
addrefs to  apply the twine without fhaking the
apparatus ;  fo that, where a number  of junc-
tures require luting, we are apt to difplace feve-
ral, while fecuring one.  In thefe cafes we  may
fubftitute flips of linen, fpread with white of egg
and lime mixed together, inftead of the wet
bladder.   Thefe are applied  while ftill moift,
and very fpeedily dry and acquire  confiderable
hardnefs.   Strong glue, diffolved in water, may
anfwer inftead of white of egg.   Thefe fillets
are ufefully applied likewife over junctures luted
together with wax and rofin. 
         OF  CHEMISTRY.     487

  Before applying a  lute, all the jundures  of
the veffels muft be accurately and firmly fitted
to each other,  fo as not to admit of being mo-
ved.   If the beak of a retort is to be luted  to
the neck of a recipient, they ought to fit pretty
accurately; otherwife we muft fix them by in-
troducing fhort pieces of foft wood,  or of cork.
If the difproportion  between the two be very
confiderable, we muft employ a cork which fits
the neck of the recipient, having a circular hole
of proper dimenfions  to admit the beak of the
retort.   The fame precaution  is neceffary  in
adapting  bent  tubes to the necks  of bottles
in the apparatus, reprefented PI. IV.  Fig.  1.
 and others of a fimilar nature.  Each mouth of
 each bottle muft be fitted with a cork, having a
 hole made with a round file of a proper fize for
 containing the tube.  And, when one mouth is
 intended to admit two or  more tubes, which
 frequently happens  when  we have  not a fuffi-
 cient  number of bottles  with  two  or  three
 necks, we muft  ufe  a cork with two or three
 holes, PI. IV. Fig.  8.
   When the  whole  apparatus is  thus folidly
 joined,  fo that no part can play upon another,
  we begin to  lute.   The  lute is  foftened by
  kneading and rolling it between  the fingers,
  with the afliltance of heat, if neceffary.   It is
  rolled into little  cylindrical pieces, and applied
  to the junctures,  taking great  care  to  make it 
488
ELEMENTS
apply clofe, and adhere firmly, in every part; a
fecond roll is applied over the firft, fo as to pafs
it on each fide ; and fo on till each juncture be
fufficiently covered. After this, the flips of blad-
der, or of linen, as above directed, muft be care-
fully  applied over all.  Though this operation
may appear extremely fimple, yet it requires pe-
culiar delicacy and management. Greatcare muft
be taken not to difturb one juncture whilft luting
another, and more efpecially when applying the
fillets and ligatures.
  Before beginning any  experiment, the  clofe-
nefs of the luting ought always to be previoufly
tried, either by  flightly  heating the retort A,
PI. IV. Fig.  i. or by blowing in a little air by
fome of the perpendicular tubes Sss s.  The al-
teration of preffure caufes a change  in the level
of  the liquid in  thefe tubes.   If the apparatus
be  accurately luted, this alteration of level will
be  permanent; whereas, if there be  the fmalleft
opening in any of the junctures, the liquid will
very foon recover its former level.  It muft al-
ways be remembered, that the whole fuccefs of
experiments in modern chemiftry depends upon
 the exactnefs of this operation, which therefore
 requires the utmoft patience, and moft attentive
 accuracy.
    It would be of infinite fervice to  enable che-
 mifts, efpecially thofe who are engaged in pneu-
 matic proceffes, to difpenfe with the  ufe of lutes, 
        OF  CHEMISTRY.      489

or at leaft to diminifli the  number neceffary in
complicated inftruments.    I  once thought of
having my apparatus conftructed  fo as to unite
in all its parts by fitting with emery, in the way
of bottles with cryftal ftoppers ;  but the execu-
tion of this plan was extremely difficult.  I have
fince thought it preferable to fubftitute  Columns
of a few lines of mercury in place of lutes ;  and
have  got  an  apparatus conftructed upon  this
principle, which appears capable of very conveni-
ent application in a great  number of circum-
ftances.
   It conTifts of a double-necked  bottle A, PI;
XII. Fig. 12.   The interior neck b c communi-
cates with the infide of the bottle : and the ex-
terior neck or rim de leaves an  interval between
the two necks, forming a deep gutter  intended
to contain  the mercury.    The  cap  or lid of
glafs B enters  this gutter, and  is properly fitted
to it, having notches in its lower  edge for the
paffage of  the tubes  which  convey the  gas.
Thefe tubes,  inftead of entering directly  into
the bottles,  as in the ordinary apparatus, have a
double bend for making them enter the gutter,
as reprefented in Fig. 13. and for making them
fit the notches of the cap B.  They  rife again
from the gutter to enter the infide of  the bottle
 over the border of the inner mouth.   When the
 tubes  are difpofed in  their proper places, and
 the cap firmly fitted on, the gutter is  filled with 
49°
ELEMENTS
mercury,  by which means  the bottle is com-
pletely excluded from any communication,  ex-
cepting through the tubes.  This apparatus may ^
be very convenient in many operations  in which
the fubftances  employed have no  action upon
mercury.   PI.  XII. Fig.  14. reprefents an  ap-
paratus upon this principle properly fitted toge-
ther.
   Mr  Seguin, to whofe aftive and intelligent
affiftance  I  have been very frequently much in-
debted, has befpoken for me, at the glafs-houfes,
fome  retorts  hermetically united to their reci-
pients, by which luting will be altogether unne-
ceffary. 
OF  CHEMISTRY.
491
            CHAP.  VIII.


Of Operations upon Combuftion and Deflagration^
               SECT.   I.

          Of Combuftion in General.


    COMBUSTION, according  to what  has
     been already faid in the Firft Part of this
Work, is the decompofition of oxygen gas pro-
duced  by a combuftible body.   The  oxygen
which forms the bafe of this gas, is abforbed by,
and enters into combination with, the burning
body, while the caloric  and light are fet free.
Every  combuftion, therefore, neceffarily fuppo-
fes oxygenation;  whereas, on the contrary,  e-
very oxygenation does n&t  neceffarily imply
concomitant combuftion;  becaufe combuftion,
properly fo called,  cannot take  place  without
difengagement  of caloric and  light.  Before
combuftion can take place, it is  neceffary that
the bafe of oxygen gas  fhould have greater affi- 
492         ELEMENTS
*nity to the combuftible body, than it has to ca-
loric :  and this elective attraction,  to ufe Berg-
man's expreffion, can only take place at a certain
degree of temperature, which is different for each
combuftible fubftance.   Hence  the neceffity of
giving a firft motion or beginning to every com-
buftion by the approach of a heated body. This
neceffity of heating any body we mean to burn,,
depends upon certain confiderations, which have
not hitherto been attended to by any natural phi-
losopher ; wherefore I fhall enlarge a little upon
the fubject in this.place.
   Nature is at  prefent in a ftate of equilibrium,
which  cannot  have been attained  until all the
fpontaneous combuftions or  oxygenations pof-
fible in the ordinary degrees of temperature had
|aken  place.   Hence, no new  combuftions or
oxygenations,  can  happen without  deftroying"
this equilibrium,  and raifing the combuftible
fubftances to a fuperior degree of  temperature.
To illuftrate this abftract view of the matter by-
example: Let us  fuppofe the ufual temperature
of the earth  a little changed,, and that it were
raj'ed only to the degree of boiling  water.  It is
evident, that, in this cafe, phofphorus, which is
combuftible in a confiderably  lower degree of
temperature, would no longer exift in nature in
its  pure and fimple ftate, but would always be
procured in its acid  or oxygenated ftate ; and its
radical would become  one of the fubftances ua- 
OF  CHEMISTRY.     49-3
known to chemiftry.  By gradually increafing
the temperature of the earth,  the fame circum-
ftance would fucceflively  happen to all the bo-
dies capable of combuftion ; and, at laft, every
poffible combuftion having taken  place, there
would no  longer  exift any combuftible body
whatever ;  as  every fubftance, fufceptible  of
that operation, would be oxygenated, and con-
fequently incotnbuftible.
  There cannot, therefore, exift, fo far as relates
to us, any combuftible body, except fuch as are
incombuftible in the ordinary temperatures of
the earth; or,  what is the fame thing, in other
words, that it is effential to the nature of every
combuftible body, not to  poffefs the property of
combuftion, unlefs heated, or raifed to the de-
gree of temperature at which its combuftion natu-
rally takes place.  When this degree is once pro-
duced, combuftion commences  ; and the caloric,
which is  difengaged by  the  decompqfition  of
the oxygen gas,  keeps up the temperature ne-
ceffary for continuing combuftion.   When this
is not the cafe, that is, when the difengaged ca-
loric is mfufficient for keeping  up the neceffary
temperature, the combuftion ceafes.   This cir-
cumftance is expreffed in common  language-
by faying, that a  body burns  ill, or with diffi-
culty.
   Although  combuftion poffeffes fome circum-
ftances in  common  with  diftillation,  efpecially 
494
ELEMENTS
witfr the compound kind of that operation, they
differ in a very material point.  In diftillation,
there is a feparation of one part of the elements
ofthe fubftance from each other, andaconfequent
combination of thefe, in a new order, occafioned
by the affinities which take place in the increafed
temperature produced during diftillation.  This
likewife happens in combuftion, but with this far-
ther circumftance, that a new element, not origi-
nally in the body, is brought into action: oxygen
is added to the fubftance fubmitted to the opera-
tion, and caloric is difengaged.
   The neceffity  of employing oxygen in the
ftate of gas in all experiments  with combuftion,
and the rigorous determination of  the quanti-
ties employed, render this  kind  of operations
peculiarly troublefome.  As almoft  all the pro-
ducts  of  combuftion are difengaged in the ftate
of gas, it is ftill more difficult to retain them
than even thofe furniflied during compound dif-
tillation.  Hence  this precaution was  entirely ne-
 glected by the ancient chemifts; and this  fet  of
 experiments exclufively belongs to modern che-
 miftry.
   Having thus pointed out,  in a general way,
 the objects  to be had in  view in experiments
 upon combuftion, I  proceed, in the following
 fections of this chapter, to defcribe the different
 inftruments  I  have ufed with this view.   The
 following arrangement  is formed,  not  upon the 
OF  CHEMISTRY.
495
nature of the combuftible bodies, but upon that
of the inftruments neceffary for combuftion,


               S EC T.   II.

       Of the  Combuftion of Phofphorus.


  In thefe combuftions, we begin by filling ajar,
capable at leaft of holding fix pints, with oxy-
gen gas, in the water apparatus, PI. V. Fig. i.
When it is perfectly full, fo that the gas begins
to flow out below,  the jar A is carried  to the
mercury apparatus, PI. IV. Fig. 3.  We then
dry the furface ofthe mercury,  both within and
without the jar, by means of blotting-paper, ta-
king care to keep the  paper for  fome time en-
tirely immerfed in the mercury before it is in-
troduced under the jar, left we let in any com-
mon air, which adheres  very obftinately to the
furface of the paper.  The body to be fubmit-
ted to combuftion, being firft  very accurately
weighed in nice fcales, is placed in a fmall flat
fhallow difh, D, of iron or porcelain.  This is
covered by  the larger cup P, which ferves the
office, of a diving bell: and the whole is paffed
through the mercury into the jar ;  after which
the larger cup is retired.  The difficulty of paf-
fing the materials of combuftion in this  manner 
496"
ELEMENTS
■through the mercury, maybe avoided by raifing
one  of the fides of the jar,  A,  for  a moment,
and flipping in the little cup, D, with the com-
buftible body,  as quickly as poffible.  In this
manner of operating, a  fmall quantity of com-
mon air gets into the jar : but it is fo very irr-
confiderable as  not to injure either the progrefs
or accuracy of  the experiment, in any fenfible
degree.
   When the cup, D, is  introduced under the
jar,  we fuck out apart of the oxygen gas,  fo as
to raife the mercury to EF, as formerly directed,
Part I. Chap. V; otherwife, when the combuf-
tible body is fet on fire,  the gas  becoming di-
lated, would be in part forced out, and we fhould
no longer be able to make any accurate calcu-
lation of the quantities before  and after the ex-
periment.   A very  convenient mode of draw-
ing out the air is by means of an air-pump fy-
ringe  adapted  to the fyphon,  GHI, by  which
 the  mercury may be raifed to any degree undei
 twenty-eight inches.  Very inflammable bodies.
 as phofphorus, are  fet on fire by means of tht
 crooked iron wire, MN, PI. IV. Fig. 16.  mad<
 red hot, and paffed quickly through the mercury
 Such as are lefs  eafily fet on fire, have a fmal
 portion of tinder, upon which a minute particli
 of phofphorus  is fixed, laid upon them  befon
 ufing the red hot iron. 
        OF  CHEMISTRY.      497

  In the firft moment of  combuftion,  the air,
being heated, rarefies, and the mercury defcends.
But when, as in combuftions of phofphorus and
iron, no elaftic*-fluid is formed,  abforption be-
comes prefently very fenfible,  and the mercury
rifes high into the jar.   Great attention rnuft be
ufed, not to burn too large a quantity of any fub-
ftance in a given quantity of gas;  otherwife, to*
wards the end of the experiment, the cup would
approach fonear the top of the jar,  as to endan-
ger breaking it, by the great heat produced, and
the fudden refrigeration from the cold mercury.
For the methods of meafuring the volume of the
gaffes,  and for correcting the meafures according
to the height ofthe barometer and thermometer,
&c. fee Chap. II. Sect. V. and VI. of this Part.
   The above procefs anfwers very well for burn-
ing all  the concrete fubftances, and even for the
fixed oils.  Thefe laft are burnt in lamps under
the jar, and are readily fet on fire by  means of
tinder, phofphorus, and hot iron.  But it is dan-
gerous for fubftances fufceptible of evaporating
in a moderate  heat, fuch as ether, alkohol, and
the effential oils. Thefe fubftances diffolve in con-
fiderable quantity in oxygen gas : and, when fet
on fire, a dangerous and fudden explofion takes
place,  which forces up the jar to a great height,
 and dafhes it in a  thoufand  pieces.  From the
 effects  of two fuch explofions, fome of the mem-
                   R rr 
493        ELEMENTS

bers of  the Academy and myfelf efcaped very
narrowly.  Befides, though this manner of ope-
rating is fufficient for determining pretty accu-
rately the quantity of oxygen gas abforbed, and
of carbonic acid produced; yet as water is likewife
formed in  all experiments  upon vegetable and
animal matters, which contain an excefs of hydro-
gen, this apparatus can neither colled it, nor de-
termine its quantity. The experiment with phof-
 phorus is even incomplete in this way; as it is im-
 poflible to demonftrate  that the weight  of thc
 phofphoric acid produced,  is equal to the  fum ot
 the weights of the phofphorus burnt and of oxy-
 gen *as abforbed during the procefs, I have been,
 therefore, obliged to vary the inftruments  accord-
 ing tocircumftances, and to employ feveral of dif-
 ferent kinds, which I fhall defcribe in their order,
 beginning with that ufed forburning phofphorus.
    Take a large balloon, A, PI. IV.  Fig. 4- of
  cryftal or white glafs,  with an opening, EF,a-
  bout two inches and a half, or three inches  dia-
  meter, to which a cap  of brafs is accurately fit-
  ted with emery, and which has two  holes  for
  the paffage ofthe tubes x x x,yyy-   Before inut-
  tino- the  balloon with its cover, place withm ^ it
  ttuTftand, BC, fupporting the cup of porcelain,
   D, which contains the phofphorus.   Then lute
   on the  cap with  fat lute, allow it to dry for
   fome days, and  weigh the whole  accurately. 
        O F  C H E M I S T R Y.      499

After this exhauft the balloon by means of an
air-pump, connected with the tube xxx,  and fill
it  with oxygen gas by the tube  yyy, from the
gazometer, PL VIII. Fig. i. defcribed Chap. II.
Sect. II. of this Part.   The  phofphorus is then
fet on fire by means of a burning-glafs;  and is al-
lowed to burn till the cloud of concrete phofpho-
ric acid (tops the combuftion,  oxygen gas being
continually fupplied from the gazometer. When
the apparatus has cooled, it -is weighed and un-
luted.  The tare of the inftrument being allowed,
the weight is that of the phofphoric acid contain-
ed.  It is proper, for greater accuracy,  to exa-
mine the air or gas contained  in the balloon after
combuftion, as  it may happen to be fomewhat
heavier or  lighter than common  air :  and this
difference of weight muft betaken into account
in the calculations upon the refults of the expe-
riment.
             SECT.  III.

        Of the Combuflion of Charcoal.


  The apparatus I have employed for this pro-
cefs, confifts of a fmall conical furnace of ham-
mered copper, reprefented inperfpective, PI. XII.
Fig. 9. and  internally difplayed Fig.  11.  It is 
500
ELEMENTS
divided into the furnace, ABC, where the char-
coal is burnt, the grate, de,  and the afh-hole,
F.  The tube, GH, in the middle ofthe  dome
of the furnace, ferves to introduce the charcoal,
and as a chimney for carrying off the. air which
has ferved for combuftion.  Through the tube,
/ 772W,  which communicates with the gazometer,
the oxygen gas, or air,  intended  for fupporting
the combuftion, is  conveyed into the afh-hole,
F, whence it is forced,  by  the  application of
preffure to the gazometer, to pafs through the
grate, d e, and to blow  upon  the burning char-
coal placed immediately above.
   Oxygen gas, which forms -^dL parts of  atmor
fpheric air, is changed into carbonic acid gas du-
ring combuftion with charcoal, while the  azotic
gas ofthe  air is not at all altered,   Hence,  after
the combuftion of charcoal in atmofpheric ^ir,
a  mixture of carbonic  acid gas and azotic gas
muft remain.  To allow this mixture to pafs off,
the tube,  op,  is adapted tp the  chimney, GH,
by means  ofafcrewat G, and conveys the gas
into bottles  half filled  with folution of cauftic
potafh.  The  carbonic  acid gas  is abforbed by
the alkali  : and the azotic gas is conveyed into
a fecond gazometer, where its quantity is  afcer-
tained.
   The weight of the furnace, ABC, is firft accu-
rately determined ;  then the tube RS, of known
weight, is introduced by  the chimney, GH, till 
OF  CHEMISTRY.
So*
its lower end S, refts  upon the grate, de, which
it occupies entirely.   In the next place, the fur-
nace is  filled with charcoal; and the whole is
weighed again, to know  the exact quantity  of
charcoal fubmitted to experiment.  The furnace
is now put in its place; the tube, / m n,  is fcrew-
ed to that which communicates with the gazome-
ter, and the tube, op, to that  which communi-
cates with the bottles  of alkaline folution. Every
thing being in readinefs, the ftop-cock of the ga-
zometer is opened ;   a fmall  piece of burning
charcoal is thrown into the tube, RS,  which is
inftantly withdrawn;  and the tube, op,  is fcrew-
ed to  the chimney,  GH.  The little  piece  of
burning charcoal falls upon the grate; and in this
manner gets below the whole charcoal; and  is
kept on fire by the ftream of air from the gazo-
meter.  To be certain that the, combuftion is be-
gun, and that it goes on properly, the tube jrj,
is fixed to the furnace, having  a piece of glafs
cemented to its upper extremity s, through which
we can fee if the charcoal be on  fire.
.  I neglected to obferve above, that the furnace,
and its appendages, are plunged into water in the
ciftern, TVXY, Fig.  n. PI. XII.  to which ice
may be added, to moderate the heat, if neceffary;
though the' heat is by no means very confider-
able, as there is no air fupplied  but what  comes
from the gazometer, and no me-rc ofthe charcoal 
502
ELEMENTS
burns at one time, than  what is immediately
over the grate.
  As one piece of charcoal is confumed, another
falls down into its place, in  confequence  of the
declivity of the fides ofthe furnace. This gets in-
to the ftream of air, from the grate, d e,  and is
burnt; and fo on,  fucceflively, till  the  whole
charcoal is confumed. The air, which has ferved
the purpofe of the combuftion, paffes through the
mafs of charcoal;  and  is forced, by the preffure
of the gazometer,  to efcape through  the tube,
0 p, and to pafs through the bottles  of alkaline
folution.
   This experiment furnifhes all the  neceffary
data for a complele analyfis of atmofpheric air
and of charcoal.  We know the weight of char-
coal confumed.  The gazometer gives us the mea-
fure of theairemptoyed. The quantity andquality
of gas remaining after combuftion^ may be deter-
mined, as it is received, either in another gazo-
meter, or in jars, in a pneumato-chemical appara-
tus.  The weight of afhes remaining in  the afh-
hole is readily afcertained :  and, finally,  the ad-
ditional weight acquired by the bottles of alka-
line folution gives the exact quantity of carbonic
acid formed during the procefs.  By this experi-
ment, we may likewife  determine, with fufficient
accuracy, the proportions in which carbon and
oxygen enter  into the  compofition  of carbonic
acid. 
         OF  CHEMISTRY.     503

  In a future memoir, I fhall give an account to
the Academy, of a feries of experiments  I have
undertaken, with this inftrument, upon  all the
vegetable and animal charcoals.  By fome very
flight alterations,  this machine may be made to
anfwer for obferving the principal phenomena of
refpiration.
              SECT.  IV.

          Of the Combuftion of Oils.


  Oils are more compound  in their nature than
charcoal, being formed by  the combination of
at leaft two elements, carbon and hydrogen.  Of
courfe, after their combuftion in  common  air,
water, carbonic acid gas, and azotic gas remain.
Hence the apparatus employed for their combuf-
tion - requires to be adapted for collecting thefe
three  products, and is confequently more con>
plicated than the charcoal furnace.
  The apparatus  I  employ for this purpofe, is
compofed of a large jar or pitcher A, PI. XII.
Fig. 4, furrounded at its upper edge by a rim of
iron,  properly cemented  at DE, and receding
from the jar  at BC,  fo as to  leave a furrow or
gutter xx, between it and the outfide of the jar. 
5°4
ELEMENTS
fomewhat more than two inches deep^  The co-
ver or lid of the jar, Fig. 5. is likewife furround-
ed by an iron rim f g, which adjufts into the
gutter xx, Fig. 4. which being filled with mer-
cury, has the effect of clofing  the jar hermeti-
cally in an inftant, without ufing any lute:  and
as the gutter will hold about two inches of mer*-
cury, the air in the jar may be made to fuftain
the preffure  of more than  two  feet of water,
without danger of its efcaping.
   The lid has four holes, T h i k, for the paffage
of an equal number of tubes.  The opening T
is furniflied with a leather box, through which
paffes the rod, Fig. 3.  intended for raifing and
lowering the wick ofthe  lamp, as will be after-
wards  directed.  The three other holes  are in-
tended for the paffage of  three feveral tubes:
one of thefe conveys the  oil to the  lamp ;  a fe-
cond conveys air  for  keeping up the combuf-
tion ; and the third carries off  the air, after  it
has ferved for combuftion.  The lamp, in which
the oil  is burnt, is reprefented Fig. 2.;  a is the
refervoir of oil, having a funnel by which it  is
filled;  b c d ef g h is a fyphon which conveys
the oil to thelamp 11; 7, 8, 9, 10, is the  tube
which conveys the air for  combuftion from the
 gazometer to the fame lamp.  The tube b c is
 formed  externally,  at its  lower end  b,  into a
 male fcrew, which turns in a female fcrew in the
 lid of the refervoir of oil a;  fo  that, by turning 
        6 t  CHEMISTR Y.      505

the refervoir one way or the other, it is made to
rife or fall, by which the oil is kept at the necef-
fary level.                                        »
  When the fyphon is to be filled, and the com-
munication fbrmed betweeri the refervoir of oil
and the lamp,  the ftop-cock  c is fhut,  and that
at £ opened. Oil is  then poured in by the open-
ing/at the top ofthe fyphon, till it rifes within
three or four lines of the upper edge of the lamp;
after which the ftop-cock k is  fhut, and that at c
opened.   The oil is next poured in at/, till the
branch bed of the fyphon is filled; and then the
ftop-cock e is clofed.  The two branches of the
fyphon being now completely filled, a communi-
cation  is fully eftablifhed between the  refervoir
and the lamp.
  In PI. XII. Fig. 1. all the parts of the lamp
11, Fig. 2. are reprefented magnified, to  fhew
them diftinctly. The tube / k  carries the oil from
the refervoir to the cavity a  a a a,  which  con-
tains the wick.  The tube  9, 10, brings the air
from the gazometer for keeping up the combuf-
tion.  This air fpreads through the cavity dddd,
and, by means of the paffages c c c c and b b b b,
is diftributed on each fide  of the wick, after the
principles  of the lamps conftru&ed by Argand,
Quinquet, and Lange.
   To render the whole of this complicated ap-
paratus more eafily  underftood, and that its de-
fcription may make  all  others of the fame  kind
                    S.s s 
506
ELEMENTS
more readily followed,  it is reprefented, com-
pletely connected together for ufe,  in PI. XL
The gazometer P furnifhes air for the combuf-
tion, by the tube and ftop-cock 1,2.   The tube
2,  3, communicates with a  feconjfl gazometer,
which is filled, while the firft one is emptying du-
ring the procefs, that there may be no interrup-
tion to the combuftion.  4, 5, is a  tube of glafs
filled with deliquefcent  falts, for drying the  air
as much as poffible in its  paffage :  and the
weight of this  tube and  its contained falts,  at
the beginning of the experiment, being  known,
it> is eafy to determine the quantity of water ab-
forbed by them from the air.  From  this deli-
quefcent tube, the air is conducted through the
pipe 5, 6, 7, 8, 9, 10, to the lamp 11, where it
fpreads on  both fides of the  wick, as before de-
fcribed, and feeds the flame.  One part of this
air, which ferves to  keep up the combuftion of
the oil,  forms carbonic acid gas  and water, by
oxygenating its elements.   Part of this  water
condenfes upon the fides ofthe pitcher A ; and
another part is held in folution  in  the air, by
means of caloric furniflied during the combuftion.
This air is forced, by the compreflion of the ga-
zometer, to pafs through the tube 12, 13,  14,
15, into the bottle  16, and the  worm 17, 18,
where the water is fully condenfed from the re-
frigeration of the air : and, if any water ftill re-
; 
OF  CHEMISTR Y.      507
main in folution, it is abforbed by  deliquefcent
falts contained in the tube 19, 20.
  All thefe  precautions are folely  intended for
collecting and determining the quantity of water
formed duringthe experiment. The carbonicacid
and azotic gas remain to be afcertained.  The
former is abforbed by cauftic alkaline folution in
the bottles 22 and  25.  I have only reprefented
two of thefe in the  figure;  but nine at leaft are
requifite: and the laft oftheferies maybe half
filled with lime-water, which is the  moft certain
reagent for  indicating the prefence of carbonic
acid.   If the lime-water be not rendered turbid,
we may be certain that no fenfible  quantity of
that acid remains in the air.              ,
   The reft ofthe air,  which has ferved for com-
buftion, and which chiefly confifts of azotic gas,
though ftill mixed  with a confiderable portion
of  oxygen gas,  which has efcaped unchanged
from  the combuftion,  is carried through a third
tube 28, 29, of deliquefcent falts,  to  deprive it
of any moifture it may  have acquired in the
bottles of alkaline folution and lime-water, and
from thence,  by the tube 29, 30, into a gazo-
meter, where its quantity is afcertained.  Small
eflays are then taken from it, which are expofed
to a folution of fulphuret of potafh, to afcertain
 the proportions of oxygen and azotic gas it con-
 tains.
   In the combuftion of oils, the wick becomes 
5o8
ELEMENTS
at laft charred, and obftructs the rife of the oil.
Befides,  if we raife the wick above a certain
height, more oil rifes through its capillary tubes,
than the  ftream of air is capable of confuming;
and fmoke is  produced.  Hence it is neceffary
to be able to lengthen or fhorten the wick with-
out opening the apparatus.  This is accompliih-
ed by means of the  rod 31, 32, 33, 34,  which
paffes through a leather box;  and  is connected
with the  fupport ofthe wick:  and that the mo-
tion of this rod, and  confequently of the wick,
may be regulated with the utmoft  fmoothnefs
and facility, it is moved at pleafure by a pinnion
which plays in a toothed rack.  The rod, with
its appendages, are  reprefented PI. XII. Fig. 3.
It appeared to me, that the combuftion would be
aflifted  by furrounding the flame  of the lamp
with a fmall glafs jar,  open at both ends, as re-
prefented in its place, in PI. XL
  I fliall not enter into  a more detailed defcrip-
tion of the conftruction of this apparatus, which
is ftill capable of being altered and modified in
many refpects; but fliall only  add,  that when  it
is to be ufed in experiments, the lamp and refer-
voir, with the contained oil, muft be accurately
weighed ; after which  it is placed as before di-
rected, and lighted.  Having then  formed the
connection  between the air  in the  gazometer
and the lamp, the external jar A, PI.  XI. is fix-
ed over all,  and fecured by means of the board 
OF  CHEMISTRY.      509
BC, and by two rods of iron which connect this
board with the  lid,  and  are fere wed to it.  A
fmall quantity of oil  is burnt, while the jar is ad-
jufting to the lid, and the product  of that com-
buftion is loft.   There is likewife a fmall portion
of air from the  gazometer loft at the fame time.
Both of thefe are of very inconfiderable confe-
quence in extenfive  experiments:  and they are
even capable of being valued in  our calculation
of the refults.
  In a particular memoir, I fhall give an account
to the Academy, of thedifficultiesinfeparablefrom
this  kind of experiments.  Thefe  are fo infur-
mountable and troublefome, that I have not hi-
therto been able to obtain any rigorous determi-
nation of the quantities of the products.  I have
fufficient proof,  however, that the fixed oils are
entirely refolved, during combuftion,  into water
and carbonic acid gas, and confequently that they
are compofed of hydrogen  and carbon.   But I
have no certain knowledge  refpecting the pro-
portions of thefe ingredients. 
5IQ
ELEMENTS
              S E  C T.   V.

        Of the Combuftion of Alkohol.


  The combuftion of alkohol may be very readi-,
ly performed in the apparatus already defcribed
for the combuftion of charcoal and phofphorus.
A lamp, filled with alkohol, is placed under the
jar A, PI. IV. Fig. 3.  and a fmall morfel of
phofphorus upon the wick of the lamp, which is
fet on fire by means of the  hot iron, as before
directed.  This procefs  is,  however, liable to
confiderable inconveniency.  It is dangerous to
make ufe of oxygen gas at the  beginning of the
experiment,  for fear of deflagration, which is
even liable to happen when common air is em-
ployed.  An accident of this kind had very near
proved fatal  to  myfelf, in prefence  of fome
members of the Academy.  Inftead of preparing
 the  experiment, as ufual, at the time it was to be
 performed,  I had difpofed  every thing  in order
 the  evening before.   The atmofpheric air of the
 jar had thereby fufficient time  to diffolve a good
 deal of the  alkohol:  and  this evaporation had
 even been confiderably promoted by the height
 of  the column of mercury,  which I had raifed
  to EF, PI. IV. Fig. 3.  The moment I attempt- 
       OF  CHEMISTRY.       511

ed to fet the little morfel of phofphorus on fire,
by means of the red hot iron, a violent explofion
took place, which threw the jar with great vio-
lence  againft the floor of  the labaratory, and
dafhed it in a thoufand pieces.
   Hence wecan only operate upon very fmallquan-
tities, fuch as ten or twelve grains of alkohol, in
this manner:  and the errors which may be com-
mitted in experiments upon fuch fmall quantities,
prevent our placing any confidence in  their re-
fults.  I endeavoured to prolong the combuftion,
in the experiments contained in the Memoirs of
the Academy  for 1784, p. 593, by lighting the
alkohol firft in common air, and furnilhing oxy-
gen gas afterwards to the jar in proportion as it
confumed.  But the carbonic acid gas, produced
by the procefs, became a great hindrance to the
combuftion, the more fo as alkohol is but diffi-
cultly combuftible, efpecially in worfethan com-
mon air ;  fo that  even in this way very fmall
quantities only could be burnt.
   Perhaps this combuftion  might fucceed better
in the oil apparatus,  PI. XL ;  but I  have not
hitherto ventured to try it.   The jar A, in which
the combuftion is performed, is near 1400 cubical
inches in dimenfion : and, were an explofion to
take place in fuch a veffel, its confequences would
be very terrible,  and  very  difficult  to  guard
againft.  1 have not,  however,  defpaired of
making the attempt. 
512
ELEMENTS
  In confequence of thefe difficulties, I have been
hitherto obliged to confine myfelf to experiments
upon very fmall quantities of alkohol,  at leaft to
combuftions made in open veffels,  fuch as that
reprefented in PL IX. Fig. 5. which  will be de-
fcribed in  Section VII. of this chapter.  If I am
ever able  to remove thefe difficulties, I fliall re-
fume this  inveftigation.
              SECT.   VI

         Of the Combifftion of Ether.

  Though the combuftion of ether in clofe vef-
fels does not prefent the fame difficulties as that
of alkohol, yetitinvolvesfomeofa different kind,
not more eafily overcome, and which ftill pre-
vent the progrefs of my experiments.   I endea-
voured to profit by  the  property which ether
poffeffes, of diffolving in atmofpheric air, and be-
ing thereby rendered inflammable without explo-
fion.  For  this purpofe, I  conftructed the refer-
voir of ether, abed, PL VII. 8. to which air is
brought from  the gazometer, by the tube 1,  2,
3, 4.   This air fpreads, in the firft place, in the
double lid  ac  of the refervoir,  from which  it
paffes through feven tubes ef, gh, ik, &c.  which
defcend to  the  bottom of the ether ;   and  it is 
         OF  CHEMISTRY.      513

forced, by the preffure of the gazometer, to boil
up  through the ether  in  the  refervoir.   We
may replace the ether in this firft refervoir,  in
proportion  as it is diffolved and carried off by
the air,  by means of the  fupplementary refer-
voir E, connected by  a brafs tube fifteen  or
eighteen inches  long,  and fliut by a ftop-cock.
This length of the conne&ing tube is to enable
the defcending ether to overcome the refiftance,
occafioned by  the preffure of the air  from the
gazometer.
   The air, thus loaded with vapours of ether,  is
conducted  by the-tube 5, 6, 7, 8, 9, to the jar
A, into which it is  allowed to efcape through a
capillary opening, at the extremity of which it is
fet on fire.  The air, when it has ferved the pur-
pofe of combuftion, paffes  through the bottle 16,
PL XI. the worm 17, 18,  and the deliquefcent
tube  19, 20; after  which it paffes through the
 alkaline  bottles.  In thefe its carbonic acid gas
 is abforbed, the water formed during the expe-
 riment having been previoufly depofited in the
 former parts of the apparatus.
    When I caufed this apparatus to be conftruct-
 ed, I fuppofed that  the combination of atmofphe-
 ric air and ether formed in the refervoir abed,
 PL XII. Fig. 8.  was in proper proportion for fup-
 porting  combuftion.  But in this I was miftaken ;
 for there is a very confiderable quantity of excefs
 of ether :  fo that an additional quantity of atmo-
                     Ttt 
5*4
E  L E  M E NT S
fpheric air is neceffary to enable it to burn fully.
Hence a lamp, conftructed upon thefe principles,
will burn in the open  air, which furnifhes the
quantity"  of oxygen neceffary for combuftion,
but will not burn in clofe veffels in which the
air is not renewed.   Owing to this circumftance,
my ether lamp went out, foon after being light-
ed and fhut up in the jar A, PL XII.  Fig. 8.
To remedy this defect, I  endeavoured to bring
atmofpheric air to the lamp, by the lateral tube,
io, n, 12, 13, 14, 15, which I diftributed cir-
cularly round the flame.   But the flame is fo ex-
ceedingly rare, that it is blown out by the gentleft
poffible ftream of air ; fo that I have not hitherto
fucceeded in burning ether.  I do not, however,
defpair of being able to accomplifh it by means of
fome changes I am  about to have made upon
this apparatus.


              SECT.  VII.

Of the Combuftion of Hydrogen Gas, and the For*
              mation  of  Water.


   In the formation of water, two fubftances,
hydrogen  and oxygen,  which are both in the
aeriform ftate before combuftion, are  transform-
ed into a liquid,  or  water, by  the  operation. 
        OF  CHEMISTRY.      515

This experiment would be very eafy, and would
only require very fimple inftruments, if it were
poflible to procure the two gaffes perfectly pure,
fo that they might  burn without any refiduum.
We  might, in that cafe, operate in very fmall
veffels, and, by continually furnilhing  the two
gaffes in proper proportions, might continue the
combuftion indefinitely.  But, hitherto, chemifts
have only employed impure oxygen gas,  mixed
with azotic gas ; from which circumftance  they
have only been able to keep up  the combuftion
of hydrogen gas for a very limited time, in clofe
veffels;  becaufe, as the refiduum of azotic gas
is continually increafing,-the air becomes at laft
fo much contaminated, that the flame weakens
and goes out. This inconvenience is fo much the
greater in proportion as the oxygen gas employ-
ed is  lefs pure.  From  this  circumftance, we
muft either be fatisfied with operating upon fmall
quantities,  or muft  exhauft  the  veffels  at in-
tervals, to get rid of the refiduum of azotic gas.
But, in this cafe,  a portion  of the water formed
during the experiment, is evaporated by the ex-
hauftion : and the refulting error is  the more
 dangerous to the accuracy of the procefs, as we
 have no certain means of afcertaining its value.
   Thefe confiderations make  me  defirous  to
 repeat the principal  experiments of pneumatic
 chemiftrv, with  oxygen gas,  entirely free from 
5ij
ELEMENTS
any admixture of azotic gas:  and this may be
procured from  oxygenated muriat  of potafli.
The oxygen gas extracted from this fait does
not appear to contain azot, unlefs accidentally ;
fo that by proper  precautions,  it may be ob-
tained perfectly pure.   In  the  mean  time, the
apparatus  employed by  Mr Meufnier and  me,
for the combuftion of  hydrogen gas,  which  is
defcribed in the experiment for recompofition of
water, Part I. Chap. VIII. and need not there-
fore be  here  repeated, will anfwer the purpofe.
When pure gaffes  are procured, this apparatus
will require no alterations, except that the capa-
city of the veffels may  then be diminifhed.  See
PL IV. Fig. 5.
   The  combuftion,  when once begun,  conti-
nues for a confiderable time ;  but weakens gra-
dually,  in proportion as the quantity of azotic
gas, remaining from the combuftion, increafes,
till at laft the azotic gas is in fuch over propor-
tion, that the combuftion can no longer be fup-
ported ; and the flame goes out.  This fponta-
neous extinction muft be prevented ; becaufe, as
the hydrogen  gas is  preffed  upon in its  refer-
voir, by an inch and a half of water, while the
oxygen gas fuffers a preffure only of three lines,
a mixture of the  two  would take  place  in the
balloon, which would at laft  be forced, by the
fuperior preffure,  into the refervoir  of oxygen
gas:  Whti^forc the  combuftion muft be ftop- 
OF  CHEMISTRY.     317
ped, by fhutting the ftop-cock of the tube d D<f
whenever the flame grows very feeble ; for which
purpofe it muft be attentively watched.
  There is  another apparatus for combuftion,
which, though we cannot with it perform expe-
riments with the fame  fcrupulous exactnefs as
with the preceding inftruments, gives very ftrik-
ing  refults,  which are extremely proper to be
fhewn in courfes of philofophical chemiftry.  It
confifts of a worm EF, PL IX. Fig. 5.  contained
in a metallic cooler ABCD.   To the upper part
of this worm E, the chimney GH is fixed, which
is compofed of two tubes, the inner of which is
a continuation of the worm ; and the  outer one
is a cafe of tin-plate, which furrounds it at about
an inch diftance, and the interval is filled up with
fand.  At the inferior extremity K of the inner
tube, a glafs tube is fixed, to which we  adopt the
Argand lamp LM for burning alkohol, Sec.
  Things being thus  difpofed,  and  the lamp
being filled with a determinate  quantity of alko-
hol,  it is fet on fire.  The water which is formed
during the combuftion, rifes in the chimney KE ;
and being condenfed  in the worm,  runs out at
its extremity F into the bottle  P.  The double
tube of the chimney, filled with fand in the in-
terftice, is to prevent  the tube from cooling in
its upper part,  and  condenfing  the water;
otherwife, it would fall back in the tube, and we
fliould  not be able to afcertain its quantity: and 
518         ELEMENTS

beficbes it  might fall in drops  upon the wick,
and extinguifh the flame.   The intention of this
conftruction, is to keep the chimney always hot,
and the worm always cool, that the water may
be preferved in  the  ftate  of vapour  while  ri-
ling, and may  be condenfed immediately upon
getting into  the defcending part of the appara-
tus.  By this inftrument, which  was contrived
by Mr Meufnier, and which is  defcribed by me
in  the Memoirs of the Academy for 1784,  p.
 593, we may, with attention to keep the worm
 always cold, collect nearly feventeen  ounces of
 water from the combuftion of fixteen ounces of
 alkohol.
              SECT.   VIII.


         Of the  Oxydation of Metals.


  The term oxydation, or calcination, is  chiefly
ufed to fignify the procefs by which metals,  ex-
pofed to a certain degree of heat, are converted
into oxyds,  by abforbing oxygen from the air.
This, combination takes place in confequence of
oxygen poffefling a greater affinity to metals, at
a  certain temperature, than to  caloric, which 
OF  CHEMJSTRY.
5*9
 becomes difengaged in its free  ftate.   But, as
 this difengagement, when made in common  air,
 is flow and progreffive, it is fcarcely evident to
 the fenfes.  It is quite otherwife,  however, when
 oxydation  takes place in oxygen gas : for, being
 produced  with much greater rapidity,  it is ge-
 nerally accompanied with heat and light, fo as
 evidently to  fhew that metallic  fubftances  are
 real combuftible bodies.
   All the  metals  have not the fame degree of
 affinity to oxygen.  Gold, filver, and platina, for
 inftance, are  incapable of taking it away from
 its combination with caloric, even in the greateft
 known heat: whereas the other metals  abforb it
 in a larger  or  fmaller quantity,  until the affini-
 ties of the  metal to oxygen, and of the  latter to
 caloric, are in exact equilibrium.  Indeed, this
 ftate of equilibrium of affinities may be  affirmed
 as a general law of nature in all combinations.
  In all operations of this nature, the oxydation
 of metals is  accelerated by giving free accefs to
 the air.  It  is fometimes much aflifted by joining
 the action of bellows, fo contrived as to  direct a
 ftream of air over the furface of the metal.   This
 procefs becomes greatly more rapid, if a ftream
 of oxygen gas be ufed, which may bereadily done
 by means of the gazometer formerly defcribed.
The metal,  in this cafe, throws  out a brilliant
flame, and the oxydation is very quickly accom- 
520
ELEMENTS
plifhed. But this method cari only be ufed in very
confined experiments, on account ofthe expence
of procuring oxygen gas. In the effay of ores, and
in all the common operations of the laboratory*
the calcination or oxydation of metals is ufually
performed in a difh of baked  clay, PL IV. Fig.
6. commonly called a roafting teft, placed in a
ftrong furnace.  The fubftances to be oxydated
are frequently ftirred, on purpofe to prefent frefh
furfaces to the air.
   Whenever this operation is performed upon a
metal which is not volatile, and from which no-
thing flies off into the furrounding air during the
procefs, the  metal  acquires additional weight.
But  the caufe of this  increafed weight during
oxydation could never have  been difcovered  by
means  of experiments performed in free  air:
and it  is  only fince thefe operations have been
performed in clofe veffels,  and  in determinate
quantities of  air, that any juft conjectures  have
been formed concerning the caufe of this pheno-
 menon. The firft method for this purpofe is due
 to Dr Prieftley,  who expafes  the metal  to be cal-
 cined in a porcelain cup N, PL IV. Fig. 11. pla-»
 ced upon the ftand IK, under a  jar A, in  the
 bafon  BCDE, full of water: the water is  made
 to rife up to GH, by  fucking out the air with a
 fyphon, and the focus of a burning glafs is made
 to fall  upon the metal.   In  a few minutes,  the 
         OF  CHEMISTRY.       521

oxydation tabes place, a part of the oxygen con-
tained in the air combines with ihe metal ; and a
proportional diminution of the volumeofairis pro-
duced. What remains, is nothing more than azo-
tic ras, ftill, however, mixed with a fmall quanti-
ty of oxygen gas.  I have given an  account of a
feries of experiments, made wiih this apparatus, in
myPhyfical and  Chemical Eflays, firft publifhed
in 17 7 3.   Mercury may be  ufod inftead of water
in this experiment, whereby the refults are ren-
dered ftill more conclufive.
  Another procefs for this purpofe  was invented
by  Mr  Boyle,  of which  I  gave  an account
in the  Memoirs  of the Academy  for 1774* P-
351.  The  metal is intreemced  into a retort,
PL III. Fig. 20.  the  beak   of  which is hermeti-
cally fealed.  The metal is "ben oxydated,  by
means of heat applied with  great  precaution.
The weight of the veffel, and its contained fub-
ftances, is not at ail changed by this procefs,
until the extremity of the neck of the retort is
broken: but, when that is done,  the external
air rufhes in with a biffing noife.   This opera-
tion is  attended with chn:;er, unlefs a part of
the air be driven out ofthe retort, by means of
heat, before it is hermetically fealed ; as, other-
wife, the retort would be apt to burft by tile di-
latation of the air, when placed in the furnace.
The quantity of  air driven out, may be received
under a  jar in  the pneumato-chemical appara-
                    V v  v 
523
ELEMENTS
tus, by  which its  quantity, and that of the air
remaining in the retort,  is afcertained.   I  have
not multiplied my  experiments upon oxydation
of metals, fo much as I could have wifhed : nei-
ther have I obtained fatisfactory refults with any
metal except tin.   It is much to be wifhed, that
fome perfon would undertake a feries of experi-
ments upon the oxydation of metals in the feve-
ral gaffes.   The fubject is important, and would
fully repay any trouble which this kind of  expe-
riment  might occafion.
   As all the oxyds of mercury are capable  of
 revivifying  without addition,  and reftore  the
oxygen  gas they had before abforbed,  this
 feemed to be the moft proper metal for beco-
 ming the fubject  of conclufive experiments up-
 on oxydation.  I formerly endeavoured  to ac-
 complifh the oxydation of mercury in clofe vef-
 fels, by filling a retort, containing a fmall  quan-
 tity of mercury, with oxygen gas, and adapting
 a bladder half full of the fame gas to its beak ;
 fee PL IV. Fig.  12.    Afterwards, by heating
 the mercury in  the retort for a very long  time,
 I fucceeded in oxydating a very fmall portion
 foas to form a little red oxyd floating upon the
 furface of the running mercury.   But the quan-
 tity was fo  fmall, that the fmalleft error  com-
 mitted in the determination  of the quantities  of
 oxygen gas, before and after the  operation, muft
 have  thrown very  great uncertainty upon  the 
         OF  CHEMISTRY.     5*3

refults of the  experiment.   I  was, befides, dif.
fatisfied with this procefs, and not without caufe,
left any air might have efcaped through the pores
of the bladder, more efpecially as it becomes fhri-
velled by the heat ofthe furnace, unlefs covered
over with cloths kept conftantly wet.
  This experiment is performed with more cer-
tainty  in  the  apparatus  defcribed in the Me-
moirs ofthe Academy  for 1775, p. 58°-  Thls
confifts of  a retort  A, PL IV. Fig. 2. having a
crooked glafs tube BCDE of ten or twelve lines
internal diameter, melted on to its  beak,  and
which  is  engaged  under  the bell glafs FG,
ftanding with  its mouth downwards, in a bafon
filled  with  water or mercury.  The retort is
placed upon the bars of the furnace MMNN,
PL IV. Fig. 2. or in a fand bath : and by means
of this apparatus we may, in the courfe  of feve-
ral days, oxydate a fmall quantity of mercury in
common air.  The red oxyd floats upon the fur-
face, from which it may be collected and revived,
 fo as to compare the quantity of oxygen gas  ob-
 tained in revivification with the abforption which
 took place during oxydation. This kind of expe-
 riment can  only be performed upon a fmall fcale,
 fo that no very certain conclufions can be drawn
 from it*.
* S«e an aerauat of this experiment, Parti. Chap. in.—A- 
524
ELEMENTS
  The combuftion of iron, in oxygen gas, being
a true  oxydation of  that metal, ought to be
mentioned  in  this place.  The apparatus em-
ployed by Mr  Ingenhoufz for this operation, is
reprefented  in PL IV.  Fig. 17.; but, having al-
ready defcribed it fufficiently in Chap. III. I fhall
refer  the reader to  what is faid of it in that
place.   Iron may likewife be oxydated by com-
buftion, in veffels filed with oxygen gas, in the
way already directed  for phofphorus and char-
coal.   This apparatus is  reprefented  PL  IV.
Fig. 3. and defcribed in  the fifth chapter ofthe
firft part of this work.  We learn from Mr In-
genhoufz, that  all the metals, except gold, fil-
ver, and mercury, may be burnt  or oxydated in
the fame  manner,  by reducing them into very
fine wire, or very thin plates cut into narrow
flips.  Thefe are twifted round with iron-wire,
which communicates the property of burning to
the other metals.
   Mercury is even  difficultly oxydated in free
air.   In chemical laboratories, this procefs is u-
fually carried  on in a matrafs A, PL  IV. Fig. 10.
having a very flat body, and a very long neck
BC,  which veffel  is commonly called Boyle's
 hell.   A quantity of  mercury is introduced, fuf-
 ficient to cover  the bottom : and it  is placed in
 a fand-bath,  which  keeps  up a  conftant heat
 approaching  to that of boiling mercury.   By
 continuing this operation with five or  fix fimi- 
OF CHEMISTRY.
S*S
Lir matraffes during feveral months,  and renew-
ing the mercury from time to time,  a few oun-
ces of red oxyd are at laft obtained.   The great
flownefs-and inconvenience of this apparatus  a-
rife  from the air not being fufficiently renewed :
but if, on the  other hand, too free a circulation
were given to the external air, it would carry off
the mercury in folution in  the date of vapour,  fo
that in a few days none would remain in the vef-
fel.
   As, of all the experiments upon the oxydation
of metals, thofe with mercury are the moft con-
clufive, it were much to be wifhed, that a fimple
apparatus could be contrived, by which this oxy-
dation and its  refults  might be demonftrated in
public courfes  of chemiftry.   This might, in my
opinion, be accompliihed by methods fimilar to
thofe I have already defcribed,for the combuftion
of charcoal and the oils.   But,  owing to other
purfuits, I have not been able hitherto to refume
this kind of experiment.
   The oxyd of mercury  revives without addi-
tion, by being heated to a flightly red heat.   In
this degree of  temperature, oxygen  has greater
affinity to caloric than to  mercury ;  and forms
oxygen gas.   This is always mixed with a fmall
portion of azotic gas, which indicates that the
mercury abforbs a fmall portion of this  latter
gas during oxydation.  It almoft always con-
tains a little carbonic acid gas,  which  muft un- 
526         ELEMENTS

doubtedly be attributed to the foulneffes of the
oxyd.   Thefe are cleared by the heat, and con-
vert a  part of the oxygen gas into carbonic
acid.                                        -
   If chemifts were reduced to the neceflity ot
procuring all the oxygen gas, employed in their
exneriments, from mercury  oxydated  by heat
without addition, or,  as it is called, calcined or
precipitated  per  fe,  the exceflive  dearnefs of
that preparation would render experiments, even
 upon  a moderate fcale,  quite  impraaicable.
 But  mercury  may  likewife  be  oxydated by
 means of  nitric acid :  and in this  way we pro-
 cure a red  oxyd,  even more pure than that pro-
 duced by  calcination.  I have fometimes pre-
 pared this oxyd by diffolving mercury in nitric
 acid,  evaporating to drynefs, and  calcining  the
 fait, either in a  retort,  or  in capfules formed
 of pieces of broken matraffes and retorts,  in
 the manner formerly defcribed.  But I have ne-
 ver   fucceeded  in  making  it equally beautiful
  with what is fold by the druggifts, and which
  is I believe, brought from Holland.   In choof-
  in* this, we ought to prefer what is in folid lumps
  compofed of foft adhering fcales  ;  as, when in
  powder,  it is. fometimes adulterated with  red
   oxyd of lead.
     To obtain oxygen  gas from the  red  oxyd ot
   mercury, I ufually  employ  a  porcelain retort,
   having a long  glafs tube adapted  to its  beak, 
OF  CHEMISTRY.
5*7
which  is engaged under jars in the water pneu-
mato-chemical apparatus:  and I  place a bottle
in the water, at the end of  the tube, for receiv-
ing the mercury, in proportion as  it revives and
diftils over.   As the oxygen gas  never appears
till the retort becomes red,  it feems to prove the
principle eftabliflied by  Mr Berthollet, that an
obfcure heat can never form oxygen gas, and
that light is one of its conftituent elements.  We
muft reject the firft portion of gas which comes
over, as being mixed  with common air, from
what was contained in  the retort at  the begin-
ning of the experiment.  But, even with this pre-
caution, the oxygen gas procured is ufually con-
taminated with a tenth  part of azotic gas, and
with a  very fmall portion of carbonic acid gas.
This latter is readily got rid of,  by making the
gas pafs through a folution of cauftic alkali: but
we know of no method for  feparating the azotic
gas. Its proportions may, however,be afcertained
by leaving a known  quantity of the oxygen  gas
contaminated with it for a fortnight, in contact
with fulphuret of foda or potafh,  which abforbs
the oxygen  gas, and  converts the fulphur into
fulphuric acid, leaving the azotic gas pure.
   We  may likewife procure oxv^en gas from
black oxyd of manganefe,or from nhrat of potafli,
by expofing  them to a red  heat,  in the appa-
ratus already defcribed  for operating upon  red 
528         E  L E  M E  N T S

oxyd of  mercury :  only, as  it requires fuch a
heat as is at leaft capable of foftening glais,  we
muft employ retorts of ftone or of porcelain  But
thepureft and beft oxygen  gas  is what is dilen-
gaged from oxygenated muriat of potafli, by Am-
ple heat.   This operation is performed in a glafs
retort, and the gas  obtained  is perfectly pure
provided that the firft portions,  which are mixed
 with the common air of the veffels, be receded. 
OF  CHEMISTRY.
529
              CHAP.   IX.

               Of Deflagration.

I HAVE  already  fhewn, Part. I.  Chap. IX.
    that  oxygen does not always part with the
whole of  the  caloric it contained in the ftate of
gas, when it enters into combination with other
bodies.   It carries almoft the whole of its caloric
along with it, on entermg into the combinations
which form nitric acid and  oxygenated muriatic
acid ; fo  that in nitrats,  and more efpecially in
oxygenated muriats, the oxygen is, in a certain
degree, in  the ftate of oxygen  gas, condenfed,
and reduced to the fmalleft volume it is capable
of occupying.
  In thefe combinations, the caloric exerts a
conftant  action upon the oxygen, to bring  it
back to the ftate of gas.  Hence the oxygen ad-
heres but very flightly;  and the fmalleft addi-
tional force is  capable of fetting it free : and,
when fuch force is applied,  it often recovers the
ftate of gas inftantaneoufly.   This rapid paffage
from the  folid to the aeriform  ftate, is called
detonation, or  fulmination,  becaufe it  is ufually
accompanied with noife and explofion.   Defla-
grations are commonly produced by  means of
combinations  of charcoal, either with nitre or
                    Xxx 
53°
ELEMENTS
with oxygenated muriat of potafli: fometimes, to
affift the inflammation, fulphur is added ;  and,
upon the juft proportion of thefe ingredients, and
the proper manipulation of  the mixture, the art
of making gunpowder depends.
   As oxygen is changed, by deflagration  with
charcoal, into carbonic acid, inftead of oxygen
gas, carbonic  acid gas is difengaged,  at leaft
when the mixture has been  made in juft propor-
tions.   In deflagration with nitre, azotic gas is
likewife difengaged ; becaufe azot is one of the
conftituent elements of nitric acid.
   The fudden and inftantaneous difengagement
and expanfion of thefe gaffes is not, however,
fufficient for explaining all the phenomena of de-
flagration ; becaufe,  if this were  the fole opera-
ting  power,  gunpowder would  always be  fo
much the ftronger in proportion  as the quantity
of gas difengaged in a given time was the more
confiderable, which does not always accord with
experiment.   I have tried fome kinds which pro-
 duced almoft double the effect of ordinary gun-
 powder, although they gave out a fixth part lefs
 of gas during deflagration.  It would appear, that
 the quantity" of caloric difengaged at the moment
 of detonation, contributes confiderably to the ex-
 panfive effects produced ;  for, although caloric
 penetrates freely through the pores of every body
 in nature, it can only do fo progreflively,  and in
 a given time.  Hence, when the quantity difenga- 
          OF  CHEMISTRY.     531

ged at once is too large to get through the pores
of the furrounding  bodies, it muft neceffarily act
in the fame way with ordinary elaftic  fluids, and
muft overturn every  thing  that oppofes its paf-
fage.  This  muft,  at leaft in part,  take place
when gunpowder is fet on fire in a cannon; as,
although the metal is permeable to caloric,  the
quantity difengaged at once is too  large to find
its way through the pores of the  metal: it muft
therefore make  an effort to efcape on every fide ;
and, as  the refiftance all round,  excepting to-
wards the muzzle,  is too great to be  overcome,
this effort  is neceffarily employed for expelling
the bullet.
  The caloric   produces  a fecond  effect, by
means of  the repulfive  force exerted  between
its particles.   It caufes the gaffes, difengaged at
the moment of deflagration, to expand with a de-
gree of force proportioned  to  the temperature
produced.
  It is very probable, that water is decompofed
during the deflagration of gunpowder, and  that
part of the oxygen furniflied to the nafcent car-
bonic acid gas  is produced  from it.   If fo, a
confiderable quantity of hydrogen gas muft be
difengaged in the inftant of deflagration, which
expands, and contributes to the force of the ex-
plofion.  It may readily be conceived, hew great-
ly this circumftance muft increafe the effect of
powder, if we confider  that a pint of hydrogen 
532
ELEMENTS
gas weighs  only one grain  and  two  thirds.
Hence a very fmall quantity  in  weight muft oc-
cupy a very large fpace :  and it muft exert  a
prodigious expanfive force in pa fling from the
liquid to the aeriform ftate of exiftence.
   In the  laft  place, as a portion  of undecom-
pofed  water is  reduced to  vapour during the
deflagration of  gunpowder, and as  water,  in
the ftate of gas, occupies feventeen or eighteen
hundred times more fpace than in its liquid ftate,
 this circumftance muft likewife contribute large-
 ly to the explofive force ofthe powder.
   I have already made a confiderable feries of
 experiments upon the nature of the elaftic fluids
 difengaged during the deflagration of nitre with
 charcoal  and  fulphur, and have made fome,
 likewife, with the oxygenated  muriat of potafh.
 This  method of  inveftigation leads to tolerably
 accurate conclufions with refpect to the confti-
 tuent elements of thefe falts.   Some of the prin-
 cipal  refults of  thefe  experiments, and of the
  confequences  drawn  from them refpe&ing the
  analyfis of nitric acid,  are reported in the  col-
  leaion of memoirs prefented to the Academy
  by foreign philofophers, vol. xi. p. 625.  Since
   then I have  procured  more convenient inftru-
   ments, and I intend to repeat thefe experiments
   upon  a larger fcale,  by which  I fhall  procure
   more accurate  precifion  in their refults.   The
   following, however, is the procefs I have hither- 
         OF  CHEMISTRY.      533

to employed.   I would very earneftly advife fuch
as intend to repeat fome of thefe experiments,
to be very much upon their  guard in operating
upon  any mixture which contains  nitre, char-
coal and fulphur, and more efpecially with thofe
in which oxygenated muriat of potafli is mixed
with thefe two materials.
  I  make ufe of piftol barrels, about fix inches
long,  and of five  or fix lines  diameter, having
the   touch-hole fpiked  up  with an iron  nail
ftrongly driven in, and broken in the hole,  and
a little tin-fmiths  folder  run in to prevent  any
poffible ifiue for  the air.  Thefe are  charged
with a mixture of known quantities of nitre and
charcoal, or any other mixture capable of de-
flagration, reduced  to an impalpable  powder,
and formed into a pafte with a moderate quan-
tity of water.   livery portion of the materials
introduced,  muft be rammed down  with a ram-
mer nearly of  the fame caliber with the barrel.-
Four or five  lines at the muzzle muft be  left
empty; and about two inches  of quick match
are added at the end of  the  charge. The only
difficulty in this experiment, efpecially when ful-
phur is contained in the mixture, is to  difcover
the proper degree of moiftening ;  for,  if the
pafte be too much  wetted, it will not take fire ;
and if too dry, the deflagration is apt to become
too rapid, and even dangerous. 
534
ELEMENTS
  When the experiment is  not intended to be
rigoroufly exact, we fet fire to the match ; and,
when it is juft about to communicate with the
charge, we plunge  the piftol below  a large bell-
glafs full  of water, in the  pneumato-chemical
apparatus.   The deflagration begins, and conti-
nues in the water ;  and gas is  difengaged  with
lefs or more rapidity, in proportion as  the  mix-
ture is more or  lefs dry.  So  long as the defla-
gration continues, the muzzle  of the piftol muft
be kept fomewhat  inclined downwards to pre-
vent the  water  from getting into its  barrel.  In
this manner I have fometimes  collected the gas
produced from the deflagration of an ounce and
half, or two ounces, of nitre.
  In this manner of operating,  it is impoflible to
determine the quantity of carbonic acid gas dif-
engaged ; becaufe a part of it is abforbed by the
water  while paffing through it.  But, when the
carbonic  acid is abforbed,  the azotic  gas re-
mains ; and, if it be agitated for a  few minutes
in cauftic alkaline  folution, we obtain it pure,
and can eafily determine its volume and weight.
We may  even, in this way, acquire a tolerably
exact knowledge of the quantity  of carbonic
acid, by repeating the experiment a great many
times, and varying the proportions  of charcoal,
till we find the exact quantity requifite to defla-
grate  the  whole nitre  employed.  Hence, by
means of the weight of charcoal employed, we 
OF   CHEMISTRY.
535
determine the weight  of oxygen  neceffary for
faturation, and deduce the quantity of  oxygen
contained in a given Weight of nitre.
   I  have ufed another  procefs, by  which the
refults of this experiment are confiderably more
accurate,  wfikh confifts in receiving the difen-
gaged gaffes in  bell-glaffes filled with  mercury.
The mercurial apparatus  I  employ  is  large
enough to contain jars of from  twelve to fifteen
pints in capacity, which are not very readily
managed when full of mercury ; and even re-
quire to be filled by a particular method. When
the jar  is placed  in the ciftern of mercury,  a
glafs fyphon is introduced, connected with  a
fmall air-pump, by means  of which the air is
exhaufted, and the mercury rifes fo as to fill
the jar.  After this, the gas of  the deflagration
is made to pafs into the jar, in the fame manner
as directed when  water is employed.
   I  muft again repeat, that this  fpecies of ex-
 periment requires  to  be  performed with the
 greateft poffible precautions.  I have  fometimes
 feen, when the difengagement of gas proceeded
 with too great rapidity, jars filled with  more
 than an  hundred and  fifty pounds of mercury,
 driven off by the  force of the explofion, and
 broken to pieces, while  the mercury was  fcat-
 tered afyout in great quantities.
   When the experiment has fucceeded, and the
 gas is  collected  under the jar, its  quantity in 
536
ELE M E N T S
general, and the nature and quantities ofthe fe-
veral fpecies of gaffes of which the mixture is
compofed, are accurately afcertained by the me-
thods already pointed out, in the fecond chapter
of this part of my  work.   I have been prevent-
ed from putting the laft hand to the experi-
ments I have begun upon deflagration, from their
connection  with the objects I am at prefent en-
gaged in ;  and I am in hopes they will  throw
confiderable  light  upon  the operations belong-
ing to the manufacture of gunpowder. 
OF  CHEMIST RY.
537
CHAP.   X.
Of the Inftruments neceffary for Operating upon
       Bodies in very high Temperatures.
               SECT.    I.

                   Of Fufion.

        "E have already feen, that, by aqueous fo-
          lution, in which theparticiee of bodies
 are feparated from each  other,  neither the fol-
 vent, nor the body held in folution, are at all de-
 compofed ;  fo that,  whenever the caufe of  fe-
 paration ceafes, the particles reunite, and fhe fa-
 line fubftance recovers precifely the fame appear-
 ance  and properties it poffeffed before  folution
 Real  folutions are produced by fire, or by in-
 troducing and accumulating a great quantity of
 caloric between the particles of bedfes : and ihis
 fpecies of folution in caloric is ufually called fu-
Jion.                                      J
   This  operation is  commonly  performed in
 vends called  crucibles, which muft neceffarily
                     Yvy 
53*
ELEMENTS
be lefs fufible than the bodies they are intended
to contain.  Hence,  in  all ages,  chemifts have
been extremely folicitous  to  procure crucibles
of very refractory materials, or fuch as are ca-
pable of refilling  a very high degree of heat.
The beft are made of very pure clay,  or of  por-
celain earth :  whereas fuch as arc made of clay,
mixed with calcareous or filicious earth, are very
fufible.   All  the  crucibles made in the neigh-
bourhood of Paris are of this kind ; and are con-
fequently unfit for moft  chemical experiments.
The  Heflian crucibles are tolerably good :  but
the beft are made of Limoges  earth, which
 feems abfolutely infufible. We have, in France,
 a great many clays  very  fit  for making cruci-
 bles ; fuch, for inftance, is the kind ufed for ma-
 king melting-pots, at the glafs manufactory of
 St Gobin.
    Crucibles are made of various forms, accor-
 ding to the operations they are intended to per-
 form.   Several of the moft common kinds are
 reprefented  PL VII. Fig. 7, 8, 9,  and  10.   The
 one reprefented at Fig. 9. is almoft  fhut at its
 mouth.
    Though  fufion may often take place without
  changing the nature of the fufed body, this ope-
  ration is frequently employed as a chemical means
  of decompofing and recompounding bodies.   In
  this way all the  metals are extracted  from their
  ores:  and, by this  procefs, they  ar# revived, 
OF  CHEMISTRY.
539
moulded, and alloyed with each other.   By this
procefs  fand  and alkali are combined to form
glafs ;  and by it  likewife  paftes,  or coloured
ftones, enamels, &c. are formed.
  The action of violent fire was much more fre-
quently  employed by the ancient chemifts than
it is in modern experiments.   Since greater pre-
cifion has been  employed  in philofophical re-
fearches, the humid has been preferred to the
dry method of procefs : and fufion  is  feldom re-
ferred to until all the other  means of analyfis
have failed.
              5 E  C  T.   II.


                Of Furnaces.


  Thefe are inftruments of moft univerfal ufe
in chemiftry :  and, as  the fuccefs  of a great
number of experiments depends upon their be-
ing well or ill  conftructed, it is of  great impor-
tance, that a laboratory  be well provided in this
refpect.  A furnace is a kind of hollow  cylin-
drical tower, fometimes widened above, PL XIII,
Fig.  i. ABCD, which  muft  have at leaft two
lateral openings ; one in its upper part F, which
is the door ofthe fire place, and one below, G, 
54o          ELEMENTS

leading to the afh-hole.  Between thefe, the fur-
nace is divided  by a horizontal grate,  intended
for fup-.orting the fuel,  the fituation of which
is marked in the figure by  the line HI.  Though
this  is the leaft complicated of all the chemical
furnaces, yet it is applicable to a great number
of purpofes.  By it, lead, tin, bifmuth, and, in
general, every fu'jftance which does  not require
a very  ftrong fire, may be  melted in crucibles.
It will ferve for metallic oxydations, for evapora-
tory veffels,  and  for fand  baths, as  in PL III.
 Fig. i. and  2.  To  render it  proper for thefe
 purpofes,  feveral notches,  m m m m,  PL > III.
 Fig. 1. are made in its upper edge ; as, otherwife,
 any pan, which might be placed over the fire,
 would flop the paffage ofthe air, and prevent the
 fuel from burning. This furnace can only produce
 a moderate degree of heat; becaufe the quantity
 of charcoal it is capable of confuming, is limited
 by the quantity of air which is allowed to pafs
  through the opening G of the afh-hole. Its power
  might°be confiderably augmented  by enlarging
  this opening :  but, then  the great ftream of air,
  whLh is convenient for fome operations, might be
  hurtful in others:  wherefore we muft have fur-
  naces of different forms, conftruaed for different
  purpofes,  in our laboratories.  There ought ef-
  pecially to be feveral of the kind now defcribed,
  of different fizes.
     The reverberatory furnace, PL XIII. Fig. 2. 
       OF  CHEMISTRY.       541

is perhaps more neceffary.   This,  like the com-
mon furnace, is compofed of the afh-hole HIKL,
the fire-place KLMN, the  laboratory MNOP,
and the dome RRSS with its funnel  or chim-
ney TTVV ; and to this  laft feveral additional
tubes may be adapted, according to  the nature
of the  different experiments.  The retort A is
placed in the divifion called the laboratory, and
is  fupported by two bars  of iron, which run a-
crofs the furnace: and its  beak comes out at a
round hole in  the fide ofthe furnace, one half
of which is  cut in  the piece called the labora-
tory, and the other in  the dome.  In moft of
the  ready-made reverbatory  furnaces, which
are fold  by the potters  at Paris, the openings
both  above and below are too fmall :  they do
not allow  a  fufficient  volume  of air to pafs
through  ; hence, as  the  quantity of charcoal
confumed,  or, what  is  much the fame thing,
the quantity of caloric difengaged, is nearly  in
 proportion  to the  quantity of a:: whieh paffes
 through the  furnace, thefe furnaces  do not
 produce a fufficient effect  in a  great number of
 experiments.   To  remedy this  defect,  there
 ought fo be two openings  GG to the  afh-hole.
 One of  thefe  is fhut up  when only a moderate
 fire is required :  and both are kept open  when
 the ftrongeft  power of  the  furnace  is  to be
 exerted.  The  opening of the dome SS ought 
542          ELEMENTS

likewife to be confiderably larger than is ufually
made.
   It is  of great importance not to employ re-
torts of too  large fize in proportion to the fur-
nace, as a fufficient fpace ought always to be al-
lowed  for the  paffage of the  air between the
fides of the furnace  and the veffel.  The retort
A in the figure is too fmall for the fize of the
furnace ; yet I find it more eafy to point out the
error than to  correct it.   The intention of the
dome is to oblige the flame and heat to furround
and ftrike back or reverberate upon every part
of the retort, whence the furnace gets the name
of reverberatory.   Without this circumftance
the retort would only  be  heated in its bottom,
the vapours  raifed  from the contained fubftance
would condenfe in the upper part, and a conti-
nual cohabitation would take place without any
thing paffing over into the receiver  ; but, by
means of this dome, the retort is equally heated
in every part, and the vapours  being forced out,
can only condenfe in  the  neck of the retort,  or
in the recipient.
   To prevent the bottom of the retort from be-
ing either heated or  cooled too fuddenly, it is
fometimes placed in a fmall fand-bath of baked
clay, ftanding upon the crofs bars of the  fur-
nace.   Likewife, in many operations, the retorts
are coated over with lutes, fome of which are in-
tended  to preferve them from  the too  fudden 
O F  C H E M I S T R Y.       543
influence of heat or of cold, while others are for
fuftaining the glafs, or forming a kind of fecond
retort, which fupports the glafs one during ope-
rations  wherein the  ftrength of the fire might
foften it.  The former  is made  of brick-clay,
with a little cow's hair" beat up with  it, into
a pafte or mortar, and  fpread  over  the  glafs
or ftone retorts.  The  latter is  made  of pure
clay and  pounded ftone-ware  mixed together,
and ufed in the fame manner.   This dries and
hardens'by the fire, fo as to form a true fupple-
mentary retort, capable  of retaining the materi-
als if the glafs retort below fhould crack or fof-
ten.  But, in  experiments which are intended
for collecting  gaffes, this lute, being porous, is
of no manner of ufe.
   In a great many  experiments, wherein  very
violent  fire is not required,  the reverberatory
furnace may be ufed as a melting one,  by leav-
ing out  the  piece called  the  laboratory, and
placing  the  dome  immediately  upon the fire-
place, as reprefented PL XIII. Fig. 3.  The fur-
nace, reprefented in  Fig 4. is very convenient
for fufions.   It is compofed ofthe fire-place and
 afh-hole ABD,  without a door, and having  a
hole E, which receives  the muzzle of a pair of
bellows ftrongly luted on, and the dome ABGH,
which ought to  be rather lower than is repre-
 fented in the figure.    This  furnace is not ca-
 pable of  producing  a  very ftrong heat;  but  is 
544
E  L E U E  N  T S
fufficient for ordinary operations,  and trey be
readily moved to any part of the laboratory where
it is wanted.   Thou eh thefe p;;:t; eular furnaces
are very  convenient, every laboratory muft be
provided with a forge  furnace, having a good
pair of bellows, or, what  is  more neceflhry, a
powerful melting furnace.  I fhall  defcribe the
one I ufe, with the principles upon which it is
conftructed.
   The air circulates in a furnace in confequence
of being heated in its paffage through  the burn-
ing coals.  It dilates; and, becoming lighter than
the furrounding air, .is  forced to  rife upwards
by the preffure of the laterel  columns of air ;
and is replaced by frefh air from all fides, efpe-
cially from below.   This  circulation of air even
takes place v,hen  coals are burnt in  a common
chaffing difh.   But  we  can readily conceive,
that, in a furnace,  open on all fides, the mafs of
air which  paffes, all other circumftances being
equal,  cannot be  fo  great as when it is obliged
to pafs through a furnace in the fhape of a hol-
low tower, like moft of the chemical furnaces;
and confequently, that the combuftion muft be
 more  rapid  in a  furnace of  this  latter con-
 ftru&ion.   Suppofe, for  inftance, the furnace
 ABCDEF open above, and  filled with burning
 coals, the force, with which the air paffes through
 the coals, will be  in proportion to the difference
 between the fpecific gravity  cf  two columns 
       OF   CHEMISTRY.        545

equal to  AC,  the one of cold  air without,  and
the other  of  heated air within  the  furnace.
There muft be fome heated air above the open-
ing AB :  and  the fuperior levity of this  ought
likewife to  be  taken into confideration.  But, as
this portion is continually  cooled  and  carried
off by the  external air,  cannot  produce  any
great  effect.
   But, if we add to this furnace a large hollow
tube GHAB of the fame diameter, which pre-
ferves the air, which has been  heated  by  the
burning coals, from being cooled and difperfed
by the furrounding air, the  difference of fpecific
gravity, which caufes the circulation, will then be
between two columns equal to GC.   Hence, if
GC be three  times the length of AC, the  cir-
culation  will  have treble force.   This  is upon
the fuppofition, that  the air  in GHCD is as
much heated as what is contained in ABCD,
which is  not ftridtly the cafe; becaufe the heat
muft  decreafe  between A3 and GH: but, as
the air in  GHAB is much warmer than the ex-
ternal  air,  it  follows, that  the addition of the
tube muft  increafe the rapidity of the ftream of
air :that  a  larger  quantity muft  pafs through
the coals; and confequently, that a greater de-
gree of combuftion muft take place.
 We  muft  not, however, conclude  from thefe
principles, that.the length of this tube ought to
be indefinitely  prolonged ; for, fince the  heat cl
                   Z z z 
546
ELEMENTS
the air gradually diminifhes in paffing from AB
to GH, even from the contact of the fides ofthe
tube, if the tube were prolonged  to  a  certain
degree, we would at laft come to a point where
the fpecific gravity of the included  air would be
equal to the air without:  and, in  this cafe,  as
the  cool air would  no longer tend to  rife up-
wards, it would become a gravitating mafs, re-
filling the afcenfion of the air below.   Befides,
as  this air, which has ferved for combuftion,  is
neceffarily mixed with  carbonic  acid gas, which
is confiderably heavier than  common air, if the
tube were made long enough, the air might  at
laft approach fo near to the temperature ofthe
external  air,  as  even  to  gravitate downwards.
Hence we muft conclude, that the length of the
tube added  to a furnace, muft  have fome limit,
beyond which it weakens, inftead  of ftrengthen-
ing, the force ofthe fire.
   From thefe  reflections it follows, that the firft
foot of tube added to a furnace produces more
effect than  the fixth, and the fixth  more than
the tenth. But we  have  no data to afcertain at
what height  we ought  to  ftop.   This limit of
 ufeful addition is fo much the farther in propor-
 tion as the materials of the lube are weaker con-
 ductors of heat, becaufe the air will thereby be
 fo  much lefs cooled :  hence   baked  earth is
 much  preferable to plate  iron.  It  would  be
 evenof confequence to make the tube double, and 
OF  CHEMISTRY.
547
to fill the interval with rammed charcoal, which
is  one of the worft known conductors of heat.
By this the refrigeration ofthe air will be retard-
ed, and the rapidity of the ftream of air confe-
quently increafed: and, by this means, the tube
may be made fo much the longer.
   As the fire-place is the hotteft part  of a fur-
nace, and the part where the air is moft dilated
in  its paffage, this part ought to be made with a
confiderable widening or  belly.   This  is the
more neceffary, as it is intended to contain the
charcoal and crucible, as well as for the  paffage
of the air which fupports, or  rather produces
the combuftion.   Hence we only allow the inter-
ftices between the coals  for the paffage of the
air.
   On thefe  principles my  melting  furnace is
conftructed,  which I believe is at  leaft equal in
power to any hitherto made: though  I   by no-
means pretend  that it  poffeffes the greateft pof-
fible intenfity that can be produced in  chemical
furnaces.  The augmentation of the volume  of
air produced during its paffage through a melt-
ing furnace, not being hitherto  afcertained from
experiment,  we are ftill unacquainted  with the
proportions which fhould exift  between  the in-
ferior and fuperior apertures: and the abfolute
fize,  of which thefe openings fliould be made, is
ftill lefs underftood.  Hence data are  wanting
by which to proceed  upon principle: and we 
54S           ELEMENTS
can only acconiplifh  the end in' view by repeal
ed trials.
  This furnace, which, according to the above-
ftated rules, is an form of  an elliptical fpheroid,
b reprefented PL XIII. Fig. 6. ABCD. It is cut
off at the two ends by two plains,  which pafs,
perpendicular to  the axis, threur;h the foci of
the ellipfe.  From thisvfhape it is capable of con-
taining  a  confiderable  quantity  of  charcoal,
while it  leaves fufficient fpace in the intervals
for the paffage  of the air.   That no  obftacle
may  oppofe the free accefs of external air, it is
perfectly  open below, after the model of Mr
 Macquer's melting furnace, and.ftands upon an
 iron tripod.  The grate is made of flat bars fet
 on edge, and with confiderable interftices.   To
 the upper part is added  a chimney, or tube, of
 baked earth, ABFG, about eighteen feet long,
 and  almoft half the diameter of the furnace.
 Though this  furnace produces a greater heat
 than any  hitherto employed  by chemifts, it is
  ftill  fufceptible of  being confiderably increafed
  in power by  the means already mentioned, the
  principal  of which  is to  render  the tube a bad
  a  conductor of heat as poffible,  by making  it
  double, and filling  the*  interval  with  rammed
  charcoal.
    When it is required  to know if lead contains
  any mixture of gold or filver it is heated in a
  ftrong fire in capfules of calcined bones, wlncn 
OF.  CHEMISTRY.
549
are called cuppels.   The lead is  oxydated be-
comes  vitrified,  and finks into the fubftance of
the cuppel;  while the gold or filver,  being in-
capable of oxydation, remain pure.   As lead
will not oxydate without free accefs of  air,  this
operation  cannot be  performed  in  a crucible
placed in the middle of the burning coals of a
furnace ; becaufe the internal air, being moftly
already reduced by the combuftion into azotic
and carbonic acid gas, is  no longer fit for the
oxydation of metals.  It was therefore neceffary,
to contrive a particular apparatus, in which the
metal  fhould be at the fame time expofed to the
influence of violent heat, and defended from con-
 tact with  air  rendered inconibuftible by its paf-
 fage through burning coals.
   The furnace intended for anfwering this double
 purpofe, is called the cuppelling or effay furnace.
 It is ufually made of a fquare form, as reprefent-
 ed PL XIII.  Fig 8. and 10.  having an afli-hole
 AABB, afire-place BBCC, a laboratory CCDD,
 and a dome DDEE.   The muffle or fmall oven
 of baked earth GH, Fig. 9. being placed in the
 laboratory ofthe furnace, upon crofs bars of iron,
 is adjufted to the opening GG, and luted with
 clay foftened in water.  The  cuppels are placed
 in  this oven or muffle, and charcoal is convey-
  ed into the furnace through  the openings of the
  dome and fire-place.   The  external air enters
  through the openings of the afh-hole for fup- 
55°
ELEMENTS
porting the combuftion, and efcapes by the fu-
perior  opening or chimney  at  EE :  and air  is
admitted through the door of the muffle GG for
oxydating the contained metal.
   Very little reflection  is fufficient to difcover
the erroneous principles upon  which  this  fur-
nace is conftructed.  When the opening GG  is
fhut, the oxydation is produced flowly, and  with
difficulty, for want of air to carry it on :  and,
when this hole is open,  the ftream of cold air,
which is then admitted, fixes the metal, and ob-
ftructs the procefs.  Thefe inconveniences may
be eafily remedied, by  constructing the muffle
and furnace in  fuch a  manner that a ftream  of
frefh external air fhould always play upon the
furface of the metal :  and this air fhould be
made to pafs  through  a pipe of clay kept con-
tinually red hot by the  fire of the furnace.  By
this means, the infide ofthe muffle will never  be
cooled ;  and  proceffes  will be finiflied in  a few
minutes, which at prefent require a confiderable
fpace of time.
   Mr Sage remedies thefe inconveniences in  a
different manner.   Fie places the cuppel contain-
ing  lead,  alloyed  with  gold or  filver, among
the charcoal of  an ordinary furnace,  and cover-
ed by a fmall porcelain muffle.  When the whole
 is fufficiently heated, he directs the blaft of a
common pair of hand-bellows upon the furface 
        OF  CHEMISTRY.       5J1

of the metal, and completes the cuppellation in
this way with great eafe and exactnefs.


              SECT.  III.

Of increafing the Aclion of Fire,  by ufing Oxygen
        Gas inftead of Atmofpheric Air.


   By means of large burning  glaffes, fuch as
thofe of Tchirnhaufen and of Mr de Trudaine, a
degree of heat is  obtained  fomewhat greater
than has hitherto  been produced in  chemical
furnaces, or even in the ovens of furnaces ufed
for baking  hard porcelain.   But thefe  inftru-
ments are extremely expenfive ; and do not even
produce heat fufficient to melt  crude platina:
fo that their advantages  are by no means fuffi-
cient to compenfate  for  the  difficulty of pro-
curing, and even of ufing them.  Concave mir-
rors produce fomewhat  more effect than  burn-
ing glaffes of the fame diameter, as is proved by
the experiments of  Meffrs Macquer and keaume
 with the fpeculum of the Abbe Bouriot.   But,
 as the direction of the reflected rays is neceffa-
 rily from below upwards, the fubftance  to be
 operated upon  muft  be  placed in the air,  with-
 out any fupport, which renders  moft chemical
 experiments impoflible to be performed with this
 inftrument. 
552
ELEMENTS
  For  thefe reafons, I firft endeavoured to em-
ploy oxygen gas in combuftion,  by filling large
bladders with it,  and making it pafs through a
tube capable of being fhut by a ftop-cock :  ar.d
in this way I fucceeded in caufing it to fupport
the combuftion of  lighted  charcoal.   The in-
tenfity of the heat produced,  even in  my  firft
attempt, was fo great, as readily to melt a fmall
quantity  of - crude plat::-..  To  the fuccefs  of
this attempt is owin-; the idea of the  gazome-
ter, defcribed p. 3S6. et feu whici: I fubftituted
inftead of the bladders; and, as we  can give
the oxygen gas any neceffary degree of preffure,
we can'with  this  inftrument keep up a conti-
nued ftream, and give it even  a very confider-
ble force.
   The only apparatus neceffary for experiments
of this kind, confifts of a fmall table, ABCD
PI XII. Fig. 15.  with  a hole F, through which
 paffes a  tube of copper or filver, ending in a
 very fmall opening at G, and capable of  being
 opened or fhut by  the ftop-cock H.   This tube
 is  continued  below the table at / m no, and is
 connected with the interior cavity of the gazome-
 ter    When we mean to operate, a hole of a fow
 lines deep, muft be made with achifel in apiece
 of charcoal, into which the fubftance to be treat-
 ed  laid, the charcoal is fet on fire by means
 of a candle and  bfow-p-Pe;  after which it is ex- 
OF  CHEMISTRY.        553
pofed to a rapid ftream of oxygen gas from  the
extremity G of the tube FG.
  This  manner  of operating  can only be ufed
with fuch bodies as may  be placed without in-
convenience, in  contact  with charcoal, fuch as
metals,  fimple earths, &c.   But, for  bodies
whofe  elements  have affinity to charcoal,  and
which  are confequently   deeompofed  by that
fubftance,  fuch  as fulphats,  phofphats,  and
moft of  the neutral falts, metallic  glaffes, ena-
mels, &c. we muft ufe. a lamp, and make the
ftream of oxygen  gas pafs through its  flame.
For this  purpofe, we ufe the elbowed blow-pipe
■ST, inftead of the bent one FG, employed with
charcoal.  The  heat produced in this fecond
 manner, is by no means fo  intenfe  as in the for-
 mer way, and is  very  difficultly made to melt
 pie.lina.   In this  manner of operating with the
 lamp,  the fubftances are placed in cuppels of cal-
 cined bones, or little cups of porcelain, or even
 in  metallic dimes.  If thefe laft be fufficiently
 large, they do not melt;  becaufe, metals being
 good conductors cfheat, the caloric  fpreads ra-
 pidly through the whole  mafs, fo that none ofies
 parts are very much heated.
    In the Memoirs  of the  Academy, for  1782,
 p. 476.  and for 1783, p, 5J3. the feries of ex-
 periments I have made with this apparatus may
 be feen at large.   The following are fome of the
  principal refults.
                      4  A 
554
ELEMENTS
  i. Rock cryftal,  to purcfilicious earth, is in-
fufible,  but becomes capable  of being foftened
or fufed when mixed with other fubftances.
  i. Lime, magnefia, and barytes, are infufible,
either when alone, or when combined together,
but, efpecially lime; they affift the fufion of eve-
ry other body.
  3. Argill, or pure bafe of alum, is completely
fufible per fe, into a very hard, opake, vitreous
fubftance, which fcratches glafs like the precious
ftones.               '
  4. All the compound earths  and ftones  ate
readily fufed into a brownifli glafs.
  5. All the faline fubftances, even fixed  alkali,
are volatilized in a few feconds.
  6.  Gold, filver, and probably platina,  are
flowly volatized  without any  particular pheno-
menon.
  7. All other metallic fubftances,  except mer-
cury, become oxydated,  though placed  upon
charcoal,  and  burn  with   different-coloured
flames, and at laft diflipate altogether.
  8. The  metallic oxyds likewife all burn with
flames.   This feems to form a diibnctive charac-
ter for thefe fubftancee,  and even leiids me to be-
lieve, as was fufptctedby Bergman, that barytes
is a metallic oxyd, though we have not hitherto
been able to obtain the metal in its pure or regu-
line ftate. 
OF  CHEMISTRY.       $55
   9. Some of the precious ftones, as rubies, are
capable of being foftened and foldered together,
without injuring their colour, or even diminifh-
ing their weights.   The  hyacinth, though al-
moft equally fixed with the ruby, lofes its colour
very readily.  The Saxon and  Brafilian topaz,
and the  Brafilian ruby,  lofe their colour very
quickly,  and lofe about a fifth of their  weight,
leaving a white earth, refembling white quartz,
or unglazed china.  The emerald, chryfolite, and
garnet, are almoft inftantly melted into an opake
and coloured glafs.
   10. The diamond  prefents a property peculiar
to itfelf.   It burns  in the  fame manner with
combuftible bodies, and is entirely diflipated.
   There is  yet another manner of employing
oxygen gas for  confiderably increafing the force
of fire, by ufing it to blow a furnace.   Mr A-
chard firft conceiyed this idea.   But the procefs
he employed, by wjiich he thought to   dephlo-
gifticate, £S it is'called, atmofpheric air, or to
deprive it o£ azo^c gas, is abfolutely  unfatis-
faftory.  I propofe  to conftruct a very  fimple
furnace,  for this purpofe,  of  very refractory
earth,  fimilar to the  one  reprefented PL XIII.
Fig. 4. but fmaller in all its  dimenfions.  It
is to have two  openings, as at E, through one
of which the nozzle of a  pair of bellows is to
pafs, by  which the  heat  is to be raifed as high
as poffible  with common air; after which, the 
$56
ELEMENTS
ftream of  common air fnjm the bellows being
fuddenly ftopt,  oxygen gas is  to  be admitted
through a tube, at the other opening, communi-
cating with  a gazometer having the preffure of
four or five inches of water.  I can in this man-
ner unite the oxygen gas from feveral gazometers,
fo as to make eight or nine cubical feet of gas
pafs through the furnace ; and in this way I ex-
pect to produce a heat greatly more  intenfe than
any hitherto known.  The upper orifice of the
 furnace muft be carefully made of confiderable
 dimenfions, that  the caloric produced may have
 free iffue, left the too fudden expanfion of that
 highly elaftic fluid fhould  produce  a dangerous
 explofion. 
APPENDIX.
No.  I.
Table for Converting Lines, or Twelfth Parts of
  an Inch, and Fractions of Lines, into Decimal
  Fraclions of the Inch.
lfth Parts	Decimal		Decimal
a line.	Fractions.	Lines.	Fractions.
I 2	O.O0694 O.OI389	I 1	O.O8333 O.16667
a	O.02083	3	O.25OOO
4	O.02778	4	0-33333
5 6 7 8	O.O3472 O.O4167 O.O4861 O.O5556	5 6 7 8	O.41667 O.5OOOO o-58333 0.66667
9 10 u	O.06250 O.06944 O.O7639	9 10 11	0.75000 °-83333 0.91667
12	O.08333	12	1.00000
 
558
APPENDIX.
No.  II.
T.ble for Convertingthe Obferved Heights of Wa-
  ter in the Jars of the Pnewnato-Chemical Appa-
  ratus, expreffed in Inches and Decimals, to Lor-
  refponding Heights of Mercury.
Water.
Mercury.
Water.
Mercury.
.1	.00737
.2	.01474
•3 •4	.02211 .02948
•5	.03685
.6	104422
.7	.05159
/ .8	.05896
•9	.06633
i.	.07370
2.	.14740
3-	.22110
4-	.29480
5-	• .56851
6.	.44221
7.	•si59l
8.	.58961
9-	.66332
10.	.73702
11.	.81072
12.	.88442
J3-	.96812
14.	1.04182
*5-	I-H552
 
APPENDIX.       559
                   No.  III.

Table for Converting the Ounce Meafures ufed
  by Dr. Prieftley into French and Englijh Cubical
  Inches*.
Ounce	French cubi-	Engliih cubi-
meafures.	cal inches.	cal inches.
I	i-567	I.898
2	3-x34	3796
•v 3	4.701	5-694
- 4	6.268	7-592
-4	7-^35	9.490
	9.402	11.388
7	10.969	13.286
' 8	12.536	15.184
'9	14.103	17.082
IO	15.670	18.980
20	3I-340	37.960
3°	47.010	56.940
40	62.680	75.920
5°	78-35o	9 j.900
6o	94.020	113.880
70	109.690	132.860
80	125.360	151.84.0
90	141.030	170.820
100	156.700	189.800
1000	1567.000	1898.000
* The ounce meafure of Dr. Pr		e^ly contains an ounce
troy, or 480 grainy	of pure water.	The Cubical center's,
 
560
APPENDIX.
            No.  IV.  Additional.

 Rules for Reducing the Degrees of Reaumur's
   and of the Swedijh Thermometer,  to the Corrc-
 , fponding  Degrees on Fahrenheit's Scale*.

   The fcale of Fahrenheit's thermometer is  di-
vided into 212 degrees, from Zero, the cold pro-
duced by a freezing mixture of fait and mow, to
the  temperature of  boiling wat'jr.-  Reaumur's
fcale has the Zero  placed at the temperature of
freezing v/ater  or melting ice ; and the interval
between that  and  the temperature of boiling
water is divided into 80 decrees.  The Swedifh
thermometer has its Zero in the fame place with
that of Reaumur ;  and the interval to the point
of boiling  water is divided into  109 degrees.
Thefe are  the principal thermometers now ufed
in Europe, and the temperature  indicated by

as given in ihe above table, are retained from ire French
of Mr 'Lovoificr, reducing  the French meafure  to  Eng-
lifh according '0 ihe beft  and moft generally  received
coivMiavifon of their ratio,  as given  more at large in Na.
V. of dm appendix.   If, however, the experiments of
Mr Ever.ird  he*  followed, as  noticed in Nr».  IX.  of
the appe.idix, the Engliih  cubical meafure of one ounce
oi'ght to hive been 18959,  ir.dead of «he above.---- T.
  * In the former edition of this *rnnflation, 1 table was
given, of the cVgrees on Reaumur's  fcale, with the cor-
refponding degrees of Fair cnl.eit, from Jfreezing to boil-
ing water. Bnt the formula in this  article were thought
more generally ufeful and more convenient.----T. 
APPENDIX.          561
 any of them may  be reduced into  the corre-
 fponding degrees on any of the others by means
 ofthe following fimple canons ; in which R fig-
 nifies the degrees  on the fcale of Reaumur, F
 thofeof Fahrenheit, and S thofe of the Swedifh
 thermometer.
   1. To convert the degrees  of  Reaumur to
 thofe of Fahrenheit  — +3*=f-
   2. To  convert the  degrees of Fahrenheit to
               ■i     F—32X4
 thofeof Reaumur;  ■-----=R.
                       9
   3. To convert the Swedifh degrees to thofe of
 Fahrenheit;  —+iz=f.
              5
   4. To convert Fahrenheit's to Swedifh;
 ------=-s.
   9
   5. To convert Swedifh degrees to thofe of
            sx+
 Reaumur; -—=R.
             5
   6. To convert Reaumur's degrees to Swedifh;
 RX5_
  4
   To fuch readers as are unacquainted with the
 algebraic expreffion of  arithmetical formulas, it
, will  be fufficient to  exprefs one or two of thefe
 in words to explain  their ufe.—1.  Multiply the
 degree of Reaumur  by 9, divide  the  product
 by 4, and to the quotient add  32,  the fum ex-
 preffes the degree on the fcale of Fahrenheit.—
 2. From the degree  of Fahrenheit fubtraft  32,
                    4B 
b62        APPENDIX
multiply the-  remainder  by 4, and divide the
product by 9, the quotient is the degree accord-
to the fcale of Reaumur, &c.
           No. V.   Additional.

Rules for Converting French Weights and Mea-
 fures into correfpondent Englifli  Denominations'*.


                 §  1. Weights.


   The Paris pound, poids  de mark of Charle-
 magne,  contains 9216 Paris grains. It is divided
 into 16 ounces, each  ounce into  8 gros,  and
 each gros into 72  grains.   It is equal to 7561
 Englifh troy grains.
   The Englifh Troy pound, of 12 ounces,  con-
 tains 5760 Engliih  Troy grains; and is equal to
 7021 Paris grains.
   The  Englifli averd-upois pound of 16  ounces
 contains 7000 Englifh Troy grains; and is equal
 to 8538 Paris grains.
 To  reduce Paris grs. to Englifh Troy"
   grs.  divide by                    I 1 2Jg
 To reduce Engliih Troy grs. to Pans j    *    y
   grs.  multiply by

   * For the materials of tilt Article, the Tranflator it indebted to Pro-
 feffor Robinfon. 
         A  P  P  E  N N D  I  X.      563

To reduce Paris ounces to Englifh "1
   Troy, divide by     -    -      I
To reduce Englifh Troy ounces to  j   '   " ^
   Paris, multiply by             J
   Or the  converfion may be made by means of
the following Tables.

   I. To reduce French to Englifh Troy weight.

The  Paris pound   =7561      ^ £   m
The  ounce        =  472.5625  \ Tf°
The gros          =   59-°7°3  \ Grams
The  Grain        =     .8 204 J


   II. To reduce Englifh Troy to Paris Weight.

The Englifh Troy pound 7__          "1
   of 12 ounces         3   '    '      I
The  Troy ounce        = 5%5'°%33 1 Paris
The  dram of 60 grs.     =   73*1354 I
The   penny weight, or 7              f
   1   r    }c   °  '    >=   20.2 C41  1 grains.
   denier,  01 24 grs.    }       y  J^   \ °
The  fcruple, of 20 grs.  =   24.3784 J
The  grain              =    1.2189 J


   III. To reduce Englifh Averdupois to Paris
                  Weight.

The averdupois pound of")             "1
   16 ounces, or 7000   ?=8538.      \ Paris
   Troy grains,         j              f grains.
The  ounce    -        = 533.6250 J 
464
APPENDIX.
        § 2. Long and Cubical Meafures

To reduce Paris running feet or in- ^
   ches into Englifh, multiply by   I  I#o6,g77
Englifh running feet or inches into \   '   *)y//
   Paris, divide by                J
To reduce Paris cubic feet or inches^
   to Englifh, multiply by       ^  V 1.211278
Englifh cubic feet or inches to Paris f
   divide by                     J
  Or by means of the following Tables:
 . IV. To reduce Paris Long Meafure to Englifh.

The Paris royal foot of) = i2
   finches          $'     '"'   I Englifli
The inch     -     -    =   1.0659   Yincles
The line, or -^ of an inch=  .0888   |
The ,V of a line     -   =  .0074 J
  V. To reduce Englijh Long Meafure to French.

The Englifh foot     =11.2596'
The inch     -       =   -9383
The 4 of an inch     =   . 1173 > Paris inches.
The t-V     -        =   -0938
The line, or-j-V      ==   .0782, 
APPENDIX.
56$
 VI. To Reduce French Cube Meafure to Englifh.

The Paris            "J Enelifh  C
 cube foot = 1.211278  [ cubical  J  2093.688384
The cubic            I*  feet,   1
 inch    = .000700  J   or    I.    1.211278
VII.  To Reduce Englijh Cube Meafure to French*.

The Englifh cube foot,7__       86 1
 or 1728 cubical inches \     ^  '*4     !  French
The cubical inch        =     .8260 r cubical
The cube tenth         =     .0008 j  inches.
          § 3.  Meafure of  Capacity.

   The Paris  pint contains 58.145! Englifh cu-
bical inches,  and the Englifh wine pint contains


  * To convert the weight of a French cubic foot of any
particular fubftance, given in French  grains, into the
correfponding weight of an Englifli cubic Foot in Engliih
troy grains ; multiply the French grains by  0.6773181,
and the produdt is  the number  of Englifh  troy grains
contained  in an Englifh  cubic  foot of  the fame fub-
ftance.

  f It  is  faid  by Belidor, Archit. HyJrog.  to contain
31 oz.  64 grs. of water, which makes it 58.075 Englifh
inches.  But, as there is confidsrable uncertainty in the

inches. 
366       APPENDIX.

28.875* cubical inches ;  or, the Paris pint con-
tains 2.0171082 Englifh pints,  and the Englifh
pint contains  .49617 Paris pints; hence,


To  reduce the Paris  pint to  the
   Englifh, multiply by
To reduce the Englifh pint to  the
   Paris, divide by


   The Septier of Paris is 7736  French, or 9370.
45 Engliih,  cubical inches;   and the Muid  is
92832 French, or  112445.4  Englifh  cubical
inches.


determinations  ofthe weight of the French cubical mea-
fure of water, owing to the uncertainty ofthe ftandards
made ufe of, it is better to abide  by Mr Everard's mea-
fure, which was made by the Exchequer ftandards, nnd
by the proportion  of the  Englifh and  French  foot, as
eftabliflied by the French Academy and Royal Society.

  * According to  Beaume, the Paris  pint contains 32
French ounces of water, at the temperature of  54.50 of
Fahrenheit ; which fliould make it  equal to 59.729 En-
glifli cubical inches.
> 2.0171082 
APPENDIX.       567
          No.  VI.  Additional.

Rules for Reducing  tbe Swedifh  Weights  and
  Meafures, ufed  by the celebrated Bergman and
  Scheele, to Engliftj denominations*.


  The Swedifh pound, which is divided like the
Englifh Apothecary or Troy pound, weighs 6556
grs. troy.
  The Kanneof pure water, according to Berg-
man, weighs 42250 Swedifh grains, and occupies
100 Swedifh cubical inches.  Hence the Kanne
of pure water weighs 48088.719444 Englifli troy
grains, or is equal to 189.9413   Englifh cubic
inches ; and the  Swedifh longitudinal inch is e-
qual to 1.238435 Englifh longitudinal inches.
  From thefe data, the following rules are de-
duced.
   t.  To reduce  Swedifh longitudinal inches to
 Eiiglifh—Multiply by 1.2384,   or  divide  by
 0.80747.
   2.  To reduce  Swedifh to Englifh cubical  in-
 ches—Multiply by  1.9, or divide by 0.5265.

  * For this article, which is ad l?d  in the prelcnt  edi-
tion, I am indebted  to the friendly advance ot Dr.  Fin.
theram.----T. 
568       APPENDIX.
  To reduce the Swedifh pound, ounce, dram,
fcruple, or grain, to the correfponding Englifh
troy denomination, multiply by 1.382, or divide
by .8786.
  4. To reduce the Swedifh Kannes to Englifh
wine pints, multiply by .1520207, or divide by
6.57804.
  5. The  Lod,  a weight fometimes ufed by
Bergman, is the 22d part of the Swedifh pound :
Therefore to reduce it to the Englifh troy pound,
multiply by .03557, or divide by 28.11 $6. 
APPENDIX.
569
                    No. VII.

Table of the  Weights ofthe different Gaffes, at
   28 French  inches, or 29.85  Englijh inches ba-
   rometrical preffure,  and at  54.50 of tempera-
   ture,  expreffed in Englift) meafure and Englijh
   Troy weight.
Names of Specific gravity,	Weight of a cu-	Weight of a cu-
the Gaffes. water being 1000	bical foot in grs.	bical inch in grs.
Atmofpheric* 1.2308	53^.45	.3IIO23
Azotic 1.1890	520.17	.243154
Oxygen 1*3562	593-32	•343345
Hydrogen 0.094671	[ 41-41	.023964
Carbonic acid 1.8454 t Nitrous 1-4631	807.34	.467326
	640.09	.370422
Ammoniacal °.73539	321.72	.l86l8o
Sulphurous acid 1.8856	824.98	.47163I
  * Thefe five were ofcemined by Mr  Lavoifier  him-
felf.----T.

  f The lad three are inferted by Mr. Lavoifier,  upon
the authority of Mr Kirwan.----T.
                      4 C 
APPENDIX.
                 No. VIII.

Tables ofthe Specific Gravities of different Bodies.

            § I. Metallic Subftances.

                GOLD.

Pure gold, of 24 carats, melted but not
   hammered,       -       -         19.2581
The fame hammered,           -     19.3617
Gold ofthe Parifian ftandard, 22 carats
   fine, not hammered*,               17.4863
The fame hammered,      -         17.5894
 Gold of the ftandard of French coin,
   21 4-| carats fine, not  hammered,    17.4022
   The fame coined,      -      -   i7-6474
 Gold of the French trinket ftandard,
   20 carats fine, not hammered,       15-7090
 The fame hammered,                I5-7746

                SILVER.

' Pure or virgin filver, 12 deniers, not
   hammered,       -       -        10^4743
 The fame hammered,         -       10.5107
 Silver of the Paris ftandard, 11 deniers
    10 grams fine, not hammeredf     10.1752
 The fame hammered,     -       -    12.3765

   * The fame with Sterling.
   ■j- This is 10grs. finer than Sterling- 
APPENDIX.        571
Silver, ftandard of French coin, 10 de-
  niers 21 grains fine, not hammered, 10.0476
The fame coined,       -       -     10.4077

             PLATINA.

Crude platina in grains       -       15.6017
The fame, after  being treated with mu-
  riatic acid,         -         -     16.7521
Purified platina, not hammered,       19.5000
The fame hammered,    -     -     20.3366
The fame drawn into wire,     -      21.0417
The fame paffed through rollers,       22.0690

       COPPE R and B R AS S.

Copper not hammered,
The fame wire drawn,
Brafs  not hammered,
The fame wire drawn,
Common caft  brafs,

         IRON  and S T E E L.

Caft iron,      -                    7.2070
Bar iron, either hardened or not,       7.7880
Steel, neither  tempered nor hardened,   7-8331
Steel hardened under the hammer, but
  not tempered.       -       -       7.8404
Steel  tempered and hardened,          7.8180
Steel, tempeied  and  ijot hardened,      7-8163
7.7880
8.8785
8.3958
8.5441
7.8240 
57*
APPENDIX.
OTHER  METALS.
Pure tin from Cornwall, melted and not	
hardened,	7.2914
The fame hardened,	7.2994
Malacca tin, not hardened,	7.2963
The fame hardened,	7-3o65
Molten lead	11.3523
Molten zinc	7.1908
Molten bifmuth,	9.8227
Molten cobalt,	8.8119
Molten arfenic,	5^33
Molten nickel,	7.8070
Molten antimony,	6.7021
Crude antimony,	4.0643
Glafs of antimony,	4.9464
Molybdena	4-7385
Tungftein, -	6.0665
Mercury -'	13.5681
Uranium,	6.4400
             § 2. Precious Stones.

White Oriental diamond,
Rofe-coloured Oriental ditto,
Oriental ruby,
Spinell ditto,
Ballas ditto,
Brafilian ditto,
Oriental topaz,
-   3.5212
    3-531°
    4.2833
    3.7600
 -    3-6458
     3-5311
     4.0106 
APPENDIX.       573
Oriental Piftachio topaz	4.0615
Brafilian ditto - •	3-5365
Saxon ditto	3.5640
Ditto white ditto	3-5535
Oriental Saphir	3-991-1
Ditto white ditto	3-9911
Saphir of Puy	4.0769
Ditto of Brafil	3-J3°7
Girafol - -	4.0000
Ceyion jargon	4.4161
Hyacinth	3-6873
Vermillion	4.2299
Bohemian garnet	4.1888
Dodecahedral ditto	4.0627
Syrian ditto	4.0000
Volcanic ditto with 24 fides	2.4684
Peruvian emerald	*-77SS
Chryfoliteof the jewellers	2.7821
Ditto of Brafil	2.6923
Beryl, or Oriental aqua marine	3.5489
Occidental aqua marine	2.7227
            § 3.  Silicious Stones.

Pure rock cryftal of Madagafcar    -  2.6530
Ditto of Brafil         -         -    2.6526
Ditto of Europe, or gelatinous       -  2.6548
Cryftallized quartz          -       -  2.6546
Amorphous ditto        -       -      2.6471
Oriental agate       -"        -      2-5901 
574       APPENDIX.

Agate onyx       -         -         2,6375
Tranfparent  calcedony     -       -    2.6640
Cornelian       -       -       -     2*6137
Sardonyx        -         -         2.6025
Prafe         -         ,        -   2'5%°5
Onyx pebble        -         -      2.6644
Pebble of Rennes       -         -    2.6538
White jade         -         -       2-95°2
Green jade         -         -       2-966°
Redjafper       -          -          2-6612
Brown ditto         -        -       *-6911
Yellow ditto       -         -        2-7IQI
Violet ditto         -          -       2-7IXI
 Grey ditto       -          -       -  2-764°
 Jafponyx           -         -      2'8l6°
 Black prifmatic hexahedral fchorl      3-3852
 Black fparry ditto       -       -^     3-3852
 Black amphorous fchorl, called antique
   bafaltes         -          -         2-9225
 Paving ftone          -         -    2-4i58
 Grind ftone       -         -         2-I4G9
 Cutler's ftone         -         -      2-IXI3
 Fountainbleau ftone      -         -   2.5616
 Scythe ftone of Auvergne       -      2.5638
 Ditto of Lorrain         -          '   2.5298
 Mill ftone         -         -         2'4835
 White flint            -         "      2'594*
  Blackifh ditto       -         -       2'S%17 
APPENDIX.       575
           § 4.  Various Stones, &c.




Opake green Italian ferpentine, or gabro
of the Florentines	2.4295
Coarfe Briancpn chalk	1.7274
Spanifh chalk	2.7902
Foliated lapis ollaris of Dauphiny	2.7687
Ditto ditto from Sweden	2.8531
Mufcovy talc -	2.7917
Black mica -	2.9094
Common fchiftus or flate	2.6718
New flate -	2.8535
White rafor hone	2.8763
Black and white hone	3-l3*i
Rhombic or Iceland cryftal	2.7151
Pyramidal calcareous fpar	2.7302
Oriental or white antique alabafter	2.7141
Green Campan marble	2.7417
Red Campan marble	2.7242
White Carara marble	2.7168
White Parian marble	2.8376
Various kinds of calcareous f!;one3 ~? from 1 .^864	
ufed in France for building 3 to Ore of Uranium	-.3902 7.5000
Heavy fpar -	4-4300
Strontitic fpar White fluor Red ditto	C3.7260 I 3-6500 3-^555 3.1911
Green ditto -	3.1817
Blue ditto	^.i682
 
576      APPENDIX.
Violet fluor -	3-*757
R'j.' Scii.ille.nt zeolite from Edelfors	2.4868
White fcintilant zeolite	2.1739
Cryftallized zeolite	2.0833
Black pitch ftone	2.0499
Yellow pitch flone	1.0860
Red ditto	2.6695
Blackifii ditto	2.3191
Red Porphyry	2.7651
Ditto of Dauphiny	2.7033
Green ferpentine	2.8960
Black ditto of Dauphiny, called variolite	: 2-9339
Green ditto from Dauphiny	2.9883
Ophites	2.9722
Granitello	3.0626
Red Egyptian granite	2.6541
Beautiful red granite	2.7609
Granite of Girardmas	2.7163
Pumice ftone	•9*45
Lapis obfidianus	2.3480
Pierre de Volvic	2.3205
Touch ftone -	2.4153
Bafaltes from Giants' Caufeway	2.8642
Ditto prifmatic from Auvergne	2-4153
Glafs gall	2.8548
Bottle glafs	27325
Green gb.fs	2.6423
White glafs	2.8922
St. Gobin cryftal	2.4882
Leith cryftal -	3.1890
 
APPENDIX.
577
Flint glafs	-	3-3293
Borax glafs	-	2.6070
Seves porcelain	-	2.1457
Limoges ditto,	-	- 2.3410
China ditto	-	2.3847
Native fulphur	-	2.0332
Melted fulphur	-	- 1.9907
Phofphorus	-	1.7140
Hard peat	-	1.3290
Ambergreafe	-	- -9263
Yellow tranfparent	amber	1.0780
§ 5. Liquids.
Diftilled water	1.0000
Rain water - -	1.0000
Filtered water of the Seine	1.00015
Arcueil water - -	1.00046
Avray water Sea water -	1.00043 1.0263
Water of the Dead Sea	1.2403
Burgundy wine Bourdeaux ditto	•9915 •9939
Malmfey Madeira Red-beer White ditto	1.0382 1.0338 1.0231
Cyder - -Highly rectified alkohol Common fpirits of wine	1.0181 .8293 .8371
4D 
578
APPENDIX.
Alkohol 15 pts. water 1 part.
14	2
13	3
12	4
I I	5
10	6
9	7
8	8
7	9
6	10
5	11
4	12
3	!3
2	14
1	15
.8527
.8674
.8815
.8947
-9°75
.9199
•93x7
.9427
•9519
•9594
.9674
•9733
 •9791
.9852
.9919
Sulphuric ether       -         -       -7394
Nitric ether          -       -       -   '9o88
Muriatic ether         -         -      .7298
Acetic ether       -      -       -     -8664
Highly concentrated Sulphuric acid     2.1250
Common Sulphuric acid               1.8409
Highly concentrated Nitric acid        1.5800
Common Nitric ditto           -      i-27I5
Muriatic ditto       -       -       -  1.1940
Fluoric acid            -         -    'S000
Red acetous ditto       -      -      1.0251
White acetous ditto      -         -  1-OI35
Diftilled ditto ditto         -       -  I-°°95 
APPENDIX
S79
Acetic acid	1.0626
Formic ditto	.9942
Solution of cauftic ammoniac, or vola-	
tile alkali fluor	.8970
Effential or volatile oil of turpentine	.8697
Liquid turpentine	.9910
Volatile oil of lavender	.8938
Volatile oil of cloves	1.0363
Volatile oil of cinnamon	1.0439
Oil of olives	■9*53
Oil of fweet almonds	.9170
Lintfeed oil	.9403
Oil of poppy feed	.9288
Oil of beech mail	.9176
Whale oil	•923S
Woman's milk	1.0203
Mare's milk	1.0346
Afs's milk	t-^ss
Goat's milk	1.0341
Ewe milk	1.0409
Cow's milk	1.0324
Cow whey	1.0193
Human urine	1.0106
           § 6. Refills and Gums.

Common yellow or white rofin         1.0727
Arcanfon        -           -       L0857 
580       APPENDIX.
Galipot*         -         -          1.0819
Baras*          -              .       1.0441
Sandarac            -           -     1.0920
Maftic          -            -          1.0742
Storax            -             -     1.1098
Opake copal         -        -         1-1398
Tranfparent ditto         -       -     1.0453
Madagafcar ditto         -         -   1.0600
Chinefe ditto         -         -      1.0628
Elemi         -         -             1.018a
Oriental anime         -         -     1.0284
Occidental ditto       -          -      1.0426
Labdanum         -          -       1.1862
Ditto in tort is          -           -    2.4933
Refm ofguaiac         -       -      1.2289
Ditto of jallap         -         -     1.2185
Dragons blood         -        -      1*2045
Gum lac          -         -          1.1390
Tacamahaca          -          -       1.0463
Benzoin       -                      1.0924
Alouchit          -         -          1.0604
Caragna}          -            -       1.1244
Elaftic gum         -           -      .9335
Camphor       -            -          .9887
Gum ammoniac       -          -      1.2071
Sagapenum           -         -     1.2008
  * Refiaous juices extracted in France from the Pine.
V'iij Bomare's D'ttt.
  -f- Odorrerous gum from the tree which produces the
Cortex Winteranus.  Ibid.
  % Refin of the tree called in Mexico Caragna, or Tree
of Madnefs.  Ibid.  , 
APPENDIX.       581
Ivy gum*
Gamboge
Euphorbium
Olibanum
Myrrh
Bdellium
Aleppo Scamony
Smyrna ditto
Galbanum
Affafoetida
Sarcocolla
Opoponax
Cherry-tree gum
Gum Arabic
Tragacanth
Baflbra gum
Acajou gumf
Monbain gum}
Infpiffated juice of liquorice
--------------Acacia
--------------Areca
Terra Japonica
Hepatic aloes
Socotrine aloes
Infpiffated juice of St John's wort
2948
2216
1244
1732
3600
37*7
2354
2743
2120
3^75
2684
6226
4817
4523
3161
4346
4456
42C6
7228
5*53
4573
3980
3586
>3795
-5^3
  * Extra&ed in Perfia and the warm countries from He-
dera terreftris.-----Bomare.
  f From a Brafilian tree of this name.  Ibid.
  $ From a tree of this name.----Ibid. 
582 A	P P E N D I X.	
Opium	,	1.3366
Indigo	-	.7690
Arnotto	-	•5956
Yellow wax	-	.9648
White ditto	-	.9686
Ouarouchi ditto*		.8970
Cacao butter	-	.8916
Spermaceti	-	•9433
Beef fat	-	.9232
Veal fat	-	•9342
Mutton fat	-	•9235
Tallow	-	.9419
Hogs fat	-	.9368
Lard	.	.9478
Butter	-	•94&3
§ 7. Woods.
Heart of oak 60	years old - 1.1700
Cork	.2400
Elm trunk	.6710
Afh ditto	.8450
Beech	.8520
Alder	.8000
Maple	- -755°
Walnut	.6710
Willow	.5850
Linden	.6040
* The produce	ofthe Taliovv Tree of Guiana. Vidt
 
APPENDIX.	5*3
Male fir	.5500
Female ditto -	.4980
Poplar -White Spanifh ditto	•383° .5294
Apple tree -Pear tree - - '	•793° .6610
Quince tree -	.7050
Medlar	.9440
Plumb tree	.7850
Olive wood	.9270
Cherry tree	•715°
Filbert tree -	.6000
French box	.9120
Dutch ditto	1.3280
Dutch yew -	.7880
Spanifh ditto Spanifh cyprefs American cedar	• .8070 .6440 .5608
Pomegranate tree Spanifh mulberry tree	!-354o .8970
Lignum vitas	i-333°
Orange tree -	.7050
  Note— The numbers i.i the above Table, if the D^imal
point be carried three figures farther to the right hnnd,
ne-arly exprefs the abfolute weight of an Fn^lifh cjbe foot
of each fub(hnce in averdupois ounces.  S-'e No. IX.  of
the Appendi::.—— T. 
584       A P P E  N D  I  X.
          No.  IX.  Additional.

Rules for Calculating  the  Abfolute  Gravity in
  Engliftj Troy Weight of a Cubic  Foot and Inch,
  Englifh Meafure, of any Subflance whofe Speci-
  fic Gravity is known*.

  In 1696, Mr Everard, balance-maker  to the
Exchequer, weighed before the Commifhoners
ofthe Houfe of Commons  2145.6 cubical inch-
es,  by the Exchequer ftandard  foot, of diftilled
water, at the  temperature  of $$°  of Fahren-
heit; and  found it to weigh 1131  oz. 14  dts.
Troy, of the  Exchequer ftandard.  The beam
turned with 6 grs. when loaded with 30 pounds
in  each  fcale.  Hence, fuppofing the  pound
averdupois to weigh 7000 grs. Troy,  a cubic
foot  of water  weighs 62 £• pounds  averdupois
or  1000 ounces aver Jupois, wanting  106 grains
Troy.  And  hence, if the fpecific gravity of
water be called 1000, the  proportional  fpecific
 gravities of all other bodies will nearly exprefs
 the number of averdupois ounces  in  a cubic
 foot.  Or, more accurately, fuppofing the fpeci-
 fic gravity of water expreffed by  t .  and of all
 other bodies  in proportional numbers, as the

   * The whole of this and the following article was com-
 inrtnicatcd to the Tranflator by Prole Hor Aobinfon----T. 
APPENDIX.          585
cubic foot of water weighs,  at the above tem-
perature, exactly 437489.4 grains Troy,  and
the cubic inch of  water 253.175  grains,  the
abfolute  weight of  a  cubical foot  or inch of
any body in Troy grains,  may be found by mul-
tiplying  their fpecific  gravity by either of the
above  numbers reflectively.
   By Everard's experiment, and the proportions
of the Englifh and French Foot, as eftablifhcd
by the Royal Society and French Academy of
Sciences, the following numbers are afcertained.

Paris grains in a Paris cube foot of
   water          -           -       =645511
Englifh grains in a Paris cube  foot
   of water        -          -       =529922
 Paris grains in an Englifh cube foot
   of water          -         -      — 533247
 Englifh  grains' in an Englifh  cube
   foot  of water          -         =437489.4
 Englifh grains in an Englifh  cube
   inch of water         -         =253.175
 By an experiment of  Picard with
   the meafure and  weight of the
   Chatelet,  the Paris cube foot of
   water contains of Paris grains      =641326
 By one of Du Hamel, made with
   great care       -      -         =641376
 By Homberg       -       -        =-641666
                      4E 
586
APPENDIX.
  Thefe  fhew fome uncertainty in meafure or
in weights;  but  the  above computation from
Everard's experiment may be relied on,  be -
caufe the comparifon of the foot  of England
with  that of France was made by the joint la-
bour of the Royal  Society of London and the
French  Academy of Sciences.  It agrees like-
wife very nearly with the weight afligned by Mr
Lavoifier, 70 Paris pounds to the cubical foot of
water. 
APPENDIX.            5*7
                   No. X.

Tables  for  Converting   Ounces,  Drams,  and
  Grains,  Troy, into  Decimals of  the Troy Pound
 of  12 Ounces,  and for  Converting  Decimals of
 the Pound Troy into Ounces,  &c.
	I.	For Grains.	
Grains	= Pound.	Grains	= Pound.
I	,0001736	IOO	.OI7361I
2	.0003472	200	.0347222
3	.0005208	300	.0520833
4	.0006944	400	.0694444
5	.OO08681	500	.0868055
J 6	.OOIO417	600	.IO41666
7	.OOI2I53	700	.1215277
8	.OOI3889	800	.1388888
9	.OOI5625	900	.1562499
10	.OOI7361	IOOO	.17361IO
20	.0034722	2000	.3472220
3°	.0052083	3OOO	.5208330
40	.0069444	4OOO	.6944440
5°	.OO86806	5000	.8680550
6o	.OIO4167	6000	I.O416660
7°	.0121528	/OOO	1.2152770
8o	.0138889	80OO	I.3888880
9°	.0156250	9OCO	I.562499C
 
588         APPENDIX.
II. For Drams.
Drams =	Pound.
I	.OIO4167
2	.0208333
3	.0312500
4	.O416667
5	.0520833
6	.0625000
7	.0729167
8	•0833333
III.	For Ounces.
Ounces =	Pounds.
I	•°%33333
1	.1666667
3	.2500000
4	•3333333
5	.4166667
6	.5000000
7	•5833333
8	.6666667
9	.7500000
JO	•8333333
n	.9166667
12	1.0000000
 
APPENDIX.
589
IV. Decimals of the Pound into Ounces,  &c.
Tenth	parts.			Thoufandths.	
lib. =	oz.	dr.	sr-	lib. =	£"•
0.1	1	I	36	o.oc6	34-56
0.2	2	3	12	0.007	40.32
0-3	3	4	48	0.008	46.08
0.4	4	6	24	0.009	51.84
o-5	6	0	0	Ten tboufandth parts.	
0.6	7	1	36	0.0001	O.576
0.7	8	3	12	0.0002	1.152
0.8	9	4	48	0.0003	I.728
0.9	10	6	24	0.0004	2.304
Hundredth parts.				0.0005	2.880
0.01	0	0	57.6	0.0006	3-456
0.02	0	1	55-2	0.0007	4.032
0.03	0	2	51.8	0.0008	4.608
0.04	0	3	50.4	0.0009	5.184
0.05	0	4	48.0	Hundred tboufandth	
0.06	0	5	45.6	parts.	
0.07	0	6	43-2	0.00001	0.057
0.08	0	7	40.8	0.00002	0.115
0.09	0	8	38.4	0.00003	0.173
Thoufandths.				0.00004	0.230
0.001	0	0	5.76	0.00005	0.288
0.002	0	0	11.52	0.00006	0.346
0.003	0	0	17.28	0.00007	0.403
0.004	0	0	23.04	0.00008	0.461
0.005	0	0	28.80	0.00009	0.518
 
59o
APPENDIX.
                  No. XI.
Table of the Englijh Cubical Inches and Decimals
  correfponding to a determinate Trey weight of'dif-
  tilled Water of the Temperature of 55°, calculated
  from Everard's experiment.
   For Grains.
Grs.   Cubical Inches.
  I  =  .0039
  2     .0079
 3
 4
 5
 6
 7
 8
 9
10
20
3°
40
5°
.0118
.0158
.0197
.0237
.0276
.0316
•0355
•0395
.0790
.1185
.1580
.1974
   For Drams.
prams Cubical Inches.
I
2
3
4
 5
 6
 7
 .2370
 •4739
 .7109
 •9479
1.1849
1.4219
1.6589
   For Ounces.
Oz.  Cubical Inches.
I  -
2
3
4
5
6
7
 8
 9
10
11
 1.8959
 3.7918
 5.6877
 7-5837
 9.4796
n-3755
13.2714
i5-l674
17.0633
18.9592
20.8551
     For Pounds
   Libs. Cubical Inches,
   1   -z.  22.7510
   2      45.502I
  3      68.2531
  4      91.0042
   5     H3-7553
   6     i36-5o63
   7     »59-^574
   8     182.0084
   9     204.7595
  10     227.5106
  50     1137-553°
 100     2275.1061
1000   22751.0615 
APPENDIX.
-591
             No. XII.   Additional.

Table ofthe Comparative Heats of different Bodies,

            as afcertained by Crawford.

Hydrogen gas                -         .         21.4000
Oxygen gas          ...          4 7490
Atmofpheric air         -                        1.7900
Steam or aqueous vapour       -             -      1.5500
Carbonic acid gas         ...     1.04.54
Arterial blood        -              -            1.0300
Water             -         -        -          1.0000
Cow's milk       -           -
Venous blood
Rice
Horfe beans
Peafe
Wheat
Barley
Oats
Pitcoal
Charcoal
Chalk
Ruft of iron
9999
8928
Azotic gas          -             -              -7936
Hide of an ox with the hair    -           -         -7870
Lungs of a fheep         -            -          "^7690
Mufcular flefti of an ox         -                     .7400
Alcohol         -        -                        .6021
5060
5020
Spermaceti oil         -                          .5000
Fruit ofthe pine tree        -         -             .5000
                                               .4920
                                               .4770
                                               .4210
                                               .4160
Sulphuric acid        -          -               .4290
.2771
.2631
.2564
 2500
Wafhed diaphoretic Antimony       -       -       .2272
Oxyd of Copper nearly freed from air       -         .2272
Quicklime        -           -         .         .2229
Cinders            -        -         _          .'02?
Afhes of Pitcoal       -           -        .         -1855
Ruft of iron nearly freed from air           -         .1666
Warned diaphoretic Antimony Do.        -          .1666
Afhes of elm wood      ...       .1403
Oxyd of Zinc nearly freed from air         -         'l3&9
Iron          .           .           .           .,269
Brafs       -           ,           .             .II23 
592
APPENDIX.
Copper
White oxyd of tin almoft free of air
Zinc
Afhes of charcoal
Tin
Yellow oxyd of lead almoft free of air
Antimony
Lead
 .mi
 .0990
 •°943
 .0909
.0704
.0680
•064.5
.0352
No. XIII.  Additional.
Table of the Ingredients in Neutral Salts, as de-
               termined by Kirwan.
	Acid Alk.	Water
Sulphuric potafh	3» 63	6
Sulphuric foda	14 22	64
Sulphurac ammoniac	42 40	18
Nitric potafh	30 63	7
Nitric foda	29 50	21
Nitric ammoniac	46 40	'4
Muriatic potafh	30 63	7
Muriatic foda	33 50	n
Muriatic ammoniac	52 40	8
Boracic foda	34 '7 Earthy Salts.	47
	Acid Earth	Water
Sulphuric magnefia	24 • 19	57
Sulphuric argill	24 18	58
Nitric calx	33 32	35
Nitric magnefia	36 27	37
Carbonic ftrontites	30 61 Metallic Salts.	9
	Acid Metal	Water
Sulphuric Iron	20 25	55
Do. Copper	30 27	43
Do. Zinc	22 20	5*
FINIS. 
Fig-. 5.
  o
Ki°-. .i
F%-4-
Plalr  1.
Kig.l
Fig.9.
Fie-. 13
FiS.l4
Fic.12
         Fie;. 10





Sold  by  M.CAREY N? 11^ Murkct StPIIILAD^ 
 
Plate  II
Viz. I.
Fig. h.
A.	5	B
1 C	1 Fie;. .J.	D
		
Pie:. 9.
SoldWM .CAREY NTOJl^ Market Si PHI LAD 4 
*
^ 
              Fig. 21.







Sold by M.CAREY, N*U8 Market S!- FHILAD4 
 
     *>   PLATE  IV
'  A A
        I Fie. .J.
SoldLv M.CAREY. N?-118 Market S\ PHILAD*
R Satjc, 
ma 
7'/*fr r
.\W'<//n*  "If. (■,!.-.-<•   \  *.?■//#.  it-?,/■ v1  »•/>'>•/   /"■■"'/.'fid
6372 
 
l.*2'/•£.'. IV.
�7394707374669 
 
fLATE VH
 
"t               \ 
^fta/.l
7>LATE TJJl.
*^ jF     [-r-rf rtjrxx^r^;
 
> 
 
f    Villi 'ii 
^LdTKX.
^ 2-  ff^m^
9346
73 
 
Z^^TJ? Al.
89999999999999999999999999999999990�
���6427�6748�0646019376893796664 
 
tt.Aix: xu.
 
 
 
I
I 
t-V
f 
 
Elements of Chemistry, Fourth Edition.
Lavoisier
Philadelphia:  1799
National Library of Medicine
Bethesda, MD

CONDITION ON RECEIPT:
The  fiill leather binding was  worn, particularly at the
corners, edges, and joints. The leather on the front board
was  cut.  The back board was detached.  The front
internal hinge was broken.  The text block consisted of
printed text and plates, many  of which were oversized
and folded several times.  The sewing was intact.  Most
of the pages were discolored, acidic, and brittle. Some
pages were foxed.  Some  plates were dirty.  Many of
these were improperly creased and torn along the edges.
The  exterior  leaves  were marked with graphite pencil
and stamp ink. A bookplate  was adhered to the front
pastedown.

TREATMENT PROVIDED:                         1*«-'   ''
The head, tail, and pages were dry cleaned. Tears were  v}£
mended and folds  guarded with Japanese kozo paper and  iq ^
wheat  starch  paste.   Improperly creased areas of the   j.^J C"
plates were flattened.  The binding was repaired  by
reattaching the back board using airplane linen, and the   *fCj 6
internal hinges were  reinforced using Japanese kozo
paper colored with acrylic pigment.                     .^ s |

Northeast Document Conservation Center
February 2002
DW/KI           _  ..         —------——  ^ 

«t&
£-&Fg
:«
rWl.W!
*&
fflV?i?V->
vi*

J*
.'•-frC^

^W;#!^,e
':«"•  ■  ..-;i
A, ■>''' :**'■
 '■ *'■ ''■'. . ,