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CHEMICAL  DIAGRAMS;

                  OR,

        CONCISE VIEWS

                  OF

   MANY INTERESTING CHANGES

               PRODUCED BY

        CHEMICAL AFFINITY.
       BY JACOB GREEN, M. D.
PROFESSOR OF CHEMISTRY IN JEFFEKSON MEDICAL COLLEGE.
J. DOBSON, 108 CHESNUT STREET.
    E. G. DORSEY, PRINTER,
          1837. 
          Annex

             QV



           GlUc.

             mi





 Entered according to the Act of Congress, A. D. 1837,
by Jacob Green, M. D., in the Clerk's Office for the
Eastern District of Pennsylvania. 
PREFACE.
  The design of the following pages is  to
present to the chemical student  some of the
most important changes produced by the re-
ciprocal action of bodies on each other, by the
aid of diagrams.   This method of illustration
has  been for a long time employed by the
author in teaching  the  practical  details  of
Chemistry,  and  it is now published at the
earnest solicitation of his pupils, and also with
a hope that it may be generally useful.
  This volume is intended merely as a com-
panion  to  more  extended treatises on the
science,  in  which the  nature and peculiar
properties of elementary substances are con-
sidered, and the numerous combinations which
they form by uniting together,  according to
fixed and unvarying  laws.  Without the pos-
session of such works, or without a good de-
gree of familiarity with the leading principles 
IV
and the practical details of the science, this
book can be of but little value.
   Numerous  methods  have  been devised
for presenting clear and brief views  of the
phenomena which  occur during  chemical
decomposition.  When conciseness alone  is
the object desired, then the methods and the
symbols employed by Berzelius will perhaps
be found the most  advantageous; but for the
purpose of aiding those little conversant with
the minutiae of modern chemistry, the plan
here exhibited has  been found preferable. As
this work treats of nothing but known facts
and established doctrines, the author can claim
but little originality in its preparation.
  To give more  interest  to  the following
pages, a few historical facts have been added,
and some practical  remarks on  the detection
of poisons. 
CHEMICAL   DIAGRAMS.
PART  I.
 OXYGEN AND ITS COMBINATIONS WITH
           ELEMENTARY  BODIES.

  Oxygen gas was discovered both by Mr. Scheele and
Dr. Priestley.  Its atomic weight or combining propor-
tion is 8. It may be obtained from several sources, but
the substances commonly employed are black oxide of
manganese, nitre,  and the  chlorate of  potash.   From
the black oxide of manganese it is procured either by
heating it to redness in an iron bottle, or by putting it,
in fine powder, into a glass retort, with an equal weight
of strong sulphuric acid, and then heating the mixture
with a lamp.

            Explanation of the processes.
  An atom of manganese weighs 28, and there are three
oxides of this metal, which are constituted as follows:
      a2 
G
                            Manganese.  Oxygen.
     Protoxide,    .     .     .     28+8 = 36
     Deutoxide,    .     .     .     28 + 12 = 40
     Per, or black oxide,     .     28 + 16 = 44
  When the peroxide is exposed to  a red heat, every
88 parts or two atoms are decomposed, 8 parts or one
atom of oxygen gas escape, and 80 parts or two atoms
of the deutoxide remain in the iron bottle.  For every
88 grains  of pure black oxide  of manganese we thus
obtain 8 grains of oxygen gas, or nearly 24 cubic inches.
  The rationale of the process by Sulphuric Acid.—Every
44 parts or each atom of the peroxide gives off 8 parts
or one atom of oxygen, and is thus converted into the
protoxide  of manganese, which unites with  the acid
and forms the sulphate of the protoxide of manganese.
  Rationale of the process by Nitre or Nitrate of Potash.
—When nitre is put into an iron bottle and heated to
redness, it first melts, and then a large quantity of oxy-
gen is evolved, the acid of the  salt being decomposed.
Every 102 parts of nitre contain
         {Oxygen  8------------Oxygen gas.
         Oxygen  8------------Oxygen gas.
         Oxygen
         Oxygen
         Oxygen   8____
         Nitrogen 14 _ZZlrr§^Hyponi-  ^    86
Potash C Potassium 40
  48
                                trous acid V hypo-
       C Potassium 40 )____________T>„foC!u f nitrite
       i Oxygen     8 J------------PotashJ potash.
  Some chemists  imagine that in this process only 8
parts  of oxygen gas are produced, and not  16, as we
have supposed above; their theory supposes that nitrite,
and not hyponitrite of potash, is left in the iron bottle. 
7
  Rationale of the process by Chlorate of Potash.—When
chlorate of potash is put  into a  small glass retort
and heated with  a  spirit  lamp nearly to redness, it  is
revolved into pure  oxygen  gas, and into the chloride
of potassium, which is left in the vessel.  The theory
of the decomposition is as follows:—Every 124 parts of
chlorate of potash contain

            COxygen 8
            I Oxygen 8
Chloric acid) Oxygen 8
     76     \ Oxygen 8
Potash 48
  Oxygen 8

i Oxygen 8
  From this explanation it appears that for every 124
grains of chlorate of potash used, 76 grains of chloride
of potassium are produced, and 48 grains, or 141 cubic
inches, of pure oxygen gas.
                 NITROGEN 14.

  Nitrogen gas was discovered by Scheele, and  also
by two or three other experimentalists.   It is prepared
by burning phosphorus in a jar of atmospheric air in-
verted in water.  Phosphoric acid is produced, and then
rapidly absorbed by the water; the residual gas is im-
pure nitrogen.
  The following table exhibits  the constitution of the
compounds of oxygen  and nitrogen by weight and vo- 
	By volume.	By weight.
	Nitroe. Oxyg.	Nitrog. Oxyg
Atmospheric air,	100 25	14 4
Protoxide of nitrogen,	100 50	14 8
Deutoxide of nitrogen,	100 100	14 16
Hyponitrous acid,	100 150	14 24
Nitrous acid,	100 200	14 32
Nitric acid,	100 250	14 40
   In  all the  above compounds the oxygen  is entirely
condensed, except in atmospheric air and the deutoxide;
in these there is no contraction of bulk whatever.
              Protoxide of Nitrogen, 22.
   The most  striking properties of this gas were first
ascertained by Sir H. Davy.   It is prepared by expos-
ing the nitrate of ammonia in a glass  retort  to the heat
of a  good  spirit lamp, the salt is then resolved into
water and the deutoxide of nitrogen.
   Every 54 parts or one equivalent of real nitric acid
(contained in 72 of the common liquid nitric acid) com-
bine with 17  of ammonia, and give 71 of dry nitrate of
ammonia, which  is resolved by the heat into  27 parts
of water and 44 of protoxide of nitrogen; as a 100
cubic inches  of this  gas weigh nearly 46 J  grains, 71
grains of the nitrate will give 95 cubic inches of this
gas, (= 44 grains.) The following diagram shows the
changes that are produced by the decomposition.
            fOx.  8......................22Prot. Nit.
                                      22  Prot. Nit.
       AcicUj °x-  !?'\  ^"..■-''
Nit. of
Amm.
71 grs
                                      9 Water.
                                      9 Water.
                                      9 Water.
 
9
  The first part of the table (to the left) represents the
elementary composition of the 54 parts of nitric acid
and the 17 of ammonia existing in 71 parts of the dry
nitrate, and the other shows the new arrangement which
these enter  into,  and the compounds produced.  The
three proportions  of hydrogen in the ammonia combine
with three of oxygen from the nitric acid, and the re-
maining proportions of oxygen come  away with the
nitrogen both of the nitric acid and the ammonia in the
form of protoxide of nitrogen.—See Reid's  Chemistry.

             Deutoxide of Nitrogen, 30.

  This gas was  discovered by Dr. Hales.   It  is ad-
vantageously obtained by the  action of nitric acid on
metallic copper.  For this purpose, copper clippings or
turnings are put into a tubulated retort, and nitric acid
diluted with one  and a half times or twice its bulk of
water is poured over them; an effervescence immediately
commences, the liquid assumes a greenish blue colour,
and the copper is  dissolved; the deutoxide of nitrogen
that is disengaged may be collected over the pneumatic
trough.
  In this process, every three equivalents of metallic
copper decompose two equivalents of nitric acid, com-
bining with the greater portion of the oxygen, and being
converted into three equivalents of the peroxide of cop-
per, each  of these at the same time unites with  one
proportion of nitric acid, forming nitrate of the peroxide
of copper, which  remains in solution;  the nitrogen of
the two proportions of nitric acid which are decomposed
comes away with the remaining oxygen  in the form of
deutoxide of nitrogen. The following diagram will con- 
10
vey a more  precise idea of the manner in which the
copper reacts upon the nitric acid which is decomposed;
the part to the left expressing the elementary constitu-
tion  of  the two proportions of nitric acid, while the
other shows the manner in which they arrange  them-
selves.
 {Nit. 14
 Ox.  8
 Ox.  8
 Ox.  8-
 Ox.  8-
 Ox.  8"
 'Ox.  8-
 Ox.
 Ox.  8.
 Ox.
 Ox.  8.
iNit. 14-
Nitric
acid 54
._- 30 Nitric oxide.


   16 +64 Cop. = 80per. C.

   16+ 64 Cop. = 80 per. C.

   16+ 64 Cop. = 80 per. C.


   30 Nitric oxide.
  The solution of nitrate of copper that remains in the
retort may be reserved for future experiments.—Reid.

               Hyponitrous Acid, 38.
  This  compound was discovered by  Gay  Lussac.
When an excess  of deutoxide of nitrogen is added to
oxygen in a glass tube containing a strong solution of
pure potash  over mercury, he found that 100 measures
of oxygen gas combined with 400 of the  deutoxide,
forming an  acid which united to the potash.  The fol-
lowing diagram will illustrate this change.  It will be
recollected that one volume of oxygen contains 2 atoms
or equivalents, and that the nitrogen and  the oxygen in
the deutoxide are under no condensation. 
11
  1 vol.   C Ox.
Oxyg. = £ Ox.
          'Nit. 14
  4 vol.
Deut. of
Ox.
Ox.
Ni«H oi.
LNit. 14
Hyponitr. acid, 38.
                                Hyponitr. acid, 38.
  The hyponitrous acid has not yet been obtained in a
free state;  for when another acid is added to the hypo-
nitrite of potash, the hyponitrous acid, instead of being
dissolved in  the water of the solution, suffers decom-
position, and is converted into nitrous acid and deutox-
ide of nitrogen, which change may be thus explained.
                                    Nitr. acid 46.
2 atoms
Hyponit,
acid 76.
INit. 14
Deut. nit. 30.
                 Nitrous Acid, 46.
  This acid seems to have been first examined in a pure
form by Sir  H. Davy.  He made this compound by
mixing two measures of deutoxide of  nitrogen and one
of oxygen,  free from moisture, in a dry vessel  pre-
viously exhausted by the air pump.  The acid gas is
distinguished by its deep orange-red  colour.   The fol-
lowing diagram shows the changes which take place in
the above experiment.

1 meas. of C Ox.
Oxyg. =1 Ox.  8
          Ox.  8
                8
               14 _   —'     ~~S^^-Nitr. acid 46.
2 deut
Nitro
-CNit.
 
                         12

                   Nitric Acid, 54.
   The chemical constitution of this  highly important
 acid was  first shown by the Hon. Henry Cavendish.
 It is obtained for commercial purposes, by decomposing
 the nitrate of potash by sulphuric  acid.  In this pro-
 cess, the materials are mixed so nearly in the proportion
 of two equivalents of sulphuric acid to one of nitrate of
 potash, that we may assume this to be the case in ex-
 plaining the reaction which ensues.  E very two equi-
 valents of the common  sulphuric acid (98)  consist of
 two equivalents of water (18) and two of dry sulphuric
 acid (80); the nitrate of potash is composed of one equi-
 valent of potash (48) and one of nitric acid (54).  The
 dry sulphuric acid combines with the potash,  forming
 bisulphate of potash, and the water goes to the nitric
 acid, forming the liquid which is condensed in the re-
 ceiver; dry nitric acid not having hitherto been procured
 in a free state, as it is always decomposed when disen-
 gaged from any of its compounds if no water is present
to condense it.  The annexed  diagram gives a clearer
view of the theory of the action, the part to  the left
 showing the composition  of  the  materials, and the
other the products of the decomposition.—See Reid.
 Pnmmrm  fwater   9..................:~- 72 com. nit. acid.
 common   Watpr   q  ............
sulphuric   ™ate.r  .1
acid 98     ^^
          I Dry Ac. 40
 Nitrate of [Nit. Ac. 54"'
potash 102\ Potash  48----     ::2M28 bis. of potash.
 
13
                 HYDROGEN 1.

  The nature and leading properties  of this gas were
first pointed out by the Hon. Henry Cavendish.  It  is
readily prepared by  pouring dilute sulphuric  acid on
small pieces of iron or zinc.
  Rationale of the process.—That the hydrogen which is
evolved from the above materials must be derived from
the decomposition of the water, is evident from the fact,
that of the three substances—iron, nitric acid and water
—the last is the only one known  to contain hydrogen.
The product of the operation, besides hydrogen, is sul-
phate of the proxide of iron, if iron be used, or of the
oxide of zinc, if zinc be employed.  The following
sketch will illustrate the changes which occur in this
process.

Water CHyd.  1
   9    I Ox.  8-,^^
Iron,         28"~^--^==^-^
Sulphuric acid 40-------------— Sulph. prot. iron 76.

  From the above it is obvious that for every 9 grains
of water decomposed, 1 grain of hydrogen will be set
free,  8 grains of oxygen and 28 grains of iron will unite
to 40 grains of sulphuric acid, and produce 76 grains  of
sulphate of the protoxide of iron. A similar calculation
may be  employed when zinc is used, by substituting
the atomic  weight  or combining  proportion of zinc,
which is 31, for that of the iron.
  Hydrogen unites with  oxygen in  two  proportions,
and with nitrogen only one  combination  has yet been
discovered.   These are as follows:
B 
14
                         By volume.   By weight.
                          Hyd.  Oxyg.  Hyd.  Oxyg.
  Protoxide of Hydrogen,     2     1       18
  Deutoxide,                1     1       1   16
                          Hyd. Nitrog. Hyd.  Nitrog.
  Ammonia,                 3     1       3   14

         Protoxide of Hydrogen or Water, 9.
  The great importance of water as a natural and as an
artificial agent, both mechanical and chemical, must be
exceedingly obvious; and a  knowledge of the exact
proportions in which oxygen and hydrogen gases unite
so as to form the liquid, is intimately connected with
much of our chemical reasonings.  The composition of
water, both by the weight and volume of its elements,
has therefore been determined with the greatest care by
the most skilful chemists.  There can be no doubt that
it is formed by the two gases in the ratio above stated.
Thus if a mixture of them, either by weight or measure
in the above proportions, be inflamed in a glass tube by
an electric  spark, they entirely disappear, and water is
the sole product.  If one volume of oxygen  is mixed
with  three of hydrogen, one volume of hydrogen re-
mains after the explosion; and a mixture of two volumes
of oxygen  and two of hydrogen leaves one volume of
oxygen. These are some of the data from which it is
inferred that oxygen gas is just 16  times as heavy as
an equal bulk of hydrogen; and as no compound of these
substances is  known which has a  less proportion of
oxygen than water, it is therefore supposed to contain
but one atom of each of its constituents. As it requires
two measures or volumes of hydrogen and only one
measure of oxygen to form water, it is concluded that 
15
     an  atom of oxygen is just half the size or bulk of an
     atom of hydrogen.

                 Deutoxide of Hydrogen, 17.
      This compound was discovered by Baron Thenard.
     It would be inconsistent with our plan to enter into the
     minute details necessary for preparing this curious sub-
     stance.  It is made by the action of the deutoxide of
     barium on water  acidulated with muriatic  acid; the
     deutoxide of barium loses one atom of its oxygen, which,
     instead of escaping as free oxygen  gas, unites to the
     water  and forms  the  deutoxide of hydrogen; the deu-
     toxide of barium is thus converted into the protoxide or
|    baryta, which  then  combines  with the  acid.   This
     change may be thus shown.

                                       Deut. of Hyd. 17
                                  Mur. Baryta 114

    Hydrogen and Nitrogen, Ammoniacal Gas, 17.
  Impure ammonia was known to the Alchemists, but
it seems first to have been noticed in a gaseous state by
Dr. Priestley and Mr. Scheele.  A convenient method
of preparing this gas is by applying a gentle heat to
the strong aqua ammonia of the shops, contained in  a
glass  retort, and catching the gas  which evolves over
mercury.  Liquid or aqua  ammonia  is merely water
changed  with the gas, and on applying heat the gas
escapes.   Another process  is also used for  obtaining
this gaseous compound.  Equal weights of muriate of
Water9=£gyd-J
Deutoxide  r Ox.
of Barium  < Ox.
    85     C Bar. 69
Muriatic acid     37
 
16
 ammonia in powder and well burned  quick-lime, just
 slaked, are put into a glass or iron vessel, heat is  ap-
 plied, and the temperature gradually increased as long
 as a free evolution of the gas continues.
   In this process the lime combines with the muriatic
 acid of the muriate of ammonia, and disengages ammo-
 niacal gas, which escapes, while a reaction at the same
 time takes place between the lime and the muriatic acid,
 and the products are, chloride  of calcium  and water.
 The diagram gives a view of the decomposition.
    Before decomposition.            After decomposition.
 ,. ,,   CAmmonia,      17----------17Ammonia.
  i a   1 M    a   c Hyd- 1 —----^ 9 Water.
 of Am. £Mur. A-°-{ CL 36 ^^"^

 28 Lime,  .  .   .   £ CaL 3(J-------^56 Chi. Cal.

   The lime is employed in larger  quantity than is ab-
 solutely necessary for the decomposition, in order that
 it may be more easily effected;  it is unnecessary to re-
 present the excess in the diagram, however, as it is not
 decomposed.—See Reid.
   The foregoing  is the explanation  commonly given,
 but perhaps the following is quite as satisfactory.
    54    f Ammonia 17
 Mur. Am. \ Mur.  Ac. 37-—-^___^
 Lime,.....28---       —-Mur. Lime 65.
   The water used in slaking the lime is not supposed
 to undergo any change on either theory.

              Nitrate of Ammonia, 71.
  Ammonia unites  to nitric acid and  forms the salt
called nitrate of ammonia, the  substance used for ob- 
17
taining protoxide of nitrogen.  It is readily formed by
neutralizing dilute nitric acid with carbonate of ammo-
nia and evaporating the solution.
                   CARBON 6.

  This element is  found pure in nature under the form
of the diamond.  In union with other substances it is
very extensively diffused. The following table exhibits
its combinations with the  three elementary bodies al-
ready mentioned.
		Weight.	Volume.
		Carb. Oxyg.	Carb. Oxyg.
Protoxide of Carbon.	i	6 + 8 = 14	2 1
Carbonic Acid,		6 + 16 = 22	1 1
Oxalic Acid, or Hypo-carbonic Acid,	}	12 + 24 = 36	2 3
		Carb. Nitrog.	Carb. Nitrog.
Cyanogen,		12 + 14 = 26	2 1
		Carb. Hyd.	Carb. Hyd.
defiant gas,		12 + 2 = 14	2 2
Fire damp,		6+2=8	1 2
        Carbonic Oxide or Protoxide of Carbon.
  The real nature of this compound was first pointed
out by Mr. Cruickshank.
  There are several processes by which this inflamma-
ble gas may be procured, most of which consist essen-
tially in depriving carbonic acid of half its oxygen by
heating it with some substance which has a great affi-
nity for this element. The best method, perhaps, con-
sists in exposing  dried chalk to heat with  an  equal
weight of iron filings, and a small quantity of charcoal,
       b2 
18
(from a fifth to a tenth part,) in an iron tube or retort,
and raising its temperature speedily in a good furnace or
open fire, till the gas begins to come.  The materials
should be reduced to as fine a state of division as pos-
sible, and the temperature must never be allowed to fall,
otherwise the gas soon ceases to come, or carbonic acid
is disengaged instead of carbonic oxide.
  In this process  the' chalk  (which  is a carbonate of
lime,) parts with its carbonic acid on exposure to heat,
and the iron and carbon mixed with it take away  one
proportion  of oxygen,  converting  it  accordingly into
carbonic oxide.  Either the iron or the carbon would
do separately, but when  they are both taken, there is
less risk of the product being contaminated with car-
bonic acid.   The following is  the rationale of the pro-
cess when chalk and carbon are used, the carbonic acid
being supposed to be expelled by heat from the chalk.
   Before decomposition.            After decomposition.  ,
Carb. acid, S°arb- «----—~U = Carb' oxide'
   90 _   ■< 0xy- 8
   22 ~   C Oxy. 8 ^__^
Carbon,  .... 6----       - 14 = Carb. oxide.

  When iron filings and chalk are employed, then  the
following change takes place.

Carb. acid, 5"°arb' <?_____--"U = Carb' oxide-
   22 —   i 0xy-8
   22 -   COxy. 8--__^
Iron,   ....  28 —^""""""^—- 36 = Oxide iron.
  Carbonic oxide may also be formed by decomposing
oxalic acid  or deutoxalate of potash by sulphuric acid;
equal measures of carbonic acid and carbonic oxide are
produced, and on removing the former by a solution of 
19
potash or lime water, the latter is left in a state of pu-
rity. To understand  the theory of this process, it must
be recollected that oxalic acid is composed of an atom
of carbonic acid and an atom of carbonic oxide—that it
cannot exist unless in combination with water or some
other substance, and that the sulphuric acid unites with
the water and the potash.  The following diagram will
illustrate the decomposition of oxalic acid by the sul-
phuric  acid, and may be readily applied to the com-
pounds of oxalic acid with the different bases.
36 Oxalic
           'Ox.  8 -      -----^.= 14 Carb. oxide.
           Ox.
Acid and<^ n V  ^
9 Water  1 Carb> 6
y water.  | CarhG--------_T^= 22 Carb. acid.
An o i \.   •   aj   c Sulphuric acid and Water 49.
40 Sulphuric acid, 3

                 Carbonic Acid, 22.
  This substance was discovered by Dr.  Black.   It is
easily prepared by the action of dilute muriatic or sul-
phuric acids on carbonate of lime; the acid unites to the
lime and the carbonic acid escapes; no heat is required
in the process.

                ("Carbon 6
  50 Carb. Lime
                ixygen

37 Muriatic aci
 ("Carbon 6 }
J  Oxygen 8 C= 22  Carbonic acid.
 |  Oxygen 8 J
 [Lime  28 7   65 Muriate Lime.
:id, .  .    3
  Carbonic acid forms three compounds by uniting to
ammonia.
  1st.  Carbonate of ammonia = 1 atom carbonic acid
and 1 ammonia. 
20
  2nd. Bicarbonate of ammonia = 2 atoms carbonic
acid and 1 ammonia.
  3d. Sesqui-carbonate of ammonia = 1| of carbonic
acid and 1 of ammonia.
  Carbonate of ammonia may be obtained by mixing
two measures  of ammonia (one equivalent) with one
measure of carbonic acid (one equivalent) over mer-
cury, the two  gases immediately combining and con-
densing in the  form of a white dry powder.
  Bicarbonate  of ammonia may be prepared by passing
a stream of carbonic  acid gas  through a  solution of
common carbonate of ammonia till it ceases to absorb
any more, and  evaporating the liquid by a very gentle
heat.
  The sesqui-carbonate of ammonia  is prepared  by
mixing muriate of ammonia and carbonate of lime, both
reduced to a fine powder, and exposing the mixture to
a strong heat in an  iron pot, covered by a dome or head,
on which the sesqui-carbonate condenses as it is sub-
limed.  The proportions  of muriate of ammonia and
carbonate of lime are one part of the former to one and
a half of the other; double decomposition takes place,
muriate of lime remains in the vessel, and the sesqui-
carbonate sublimes. The following diagram will illus-
trate the changes.

                                   = 50Ses. Carb.'
65 Mur. of lime.
1 atom  r .
Mur.of J Ammoma  17
     lia(jVlur. acid  37
 Mur. of
Ammonia
   -i    i  iviur. amu  «5/\

           ljCarb.ac.33
1£ Carb.
of Lime
Lime
28
 
21
  This compound, which is the carbonate of ammonia
of the shops, always contains a portion of water.

        Hypo-carbonic Acid or Oxalic Acid, 36.
  The true constitution of.this body seems to have been
first established by Berzelius.  It occurs abundantly in
certain plants, in combination with lime or potash.  It
is commonly prepared by digesting sugar in five or six
times its weight of nitric acid; very complicated changes
ensue, which produce not only the oxalic acid and gene-
rate water, but also form deutoxide of nitrogen, carbonic
acid, hyponitrous acid, and probably formic acid. The
following diagram will illustrate some of these changes.

                                     36 Oxalic acid.
27 Water.
                                   30 Deutox. Nitr.
  One atom of carbon in the above rationale is not ac-
counted for but  by decomposing two atoms of nitric
acid instead of one, as in the diagram; then we  should
form with this atom of carbon, one atom of carbonic
acid and one of the hyponitrous acid, thus:
 3 atoms
of Sugar
   45
 1 atom
of Nitric
 Acid 54
 
oo
         Carb. 6------------—^ = 2'2 (Carbonic acid.
        fOx.   8 -—~^^^
         Ox.   8-"^
Nitric J Ox.   8
  acid  \ Ox.   8C>>.
        | Ox.   8-~_^£^.
        ^Nit.  14--    ~~^^^ = 38 Hyponit. acid.
  It follows, therefore,  on the  foregoing supposition,
that 3 atoms of sugar = 45 and 2 atoms of nitric acid
= 108, produce by a new arrangement of their elements
after decomposition
           1 Oxalic acid           = 36
           3 Water               = 27
           1 Deutoxide of Nitrogen = 30
           1 Hyponitrous acid      = 38
           1 Carbonic acid         = 22 = 153
  The mellitic acid found in the honey-stone, according
to Wohler and. Leibig, is formed exclusively of oxygen
and carbon, in the ratio of  4 atoms of carbon = 24 and
3 atoms of oxygen = 24.
  The croconic  acid of Gmelin is  another vegetable
product, which consists of 5 atoms of carbon = 30 and
4 of oxygen = 32.

       Carbon and Nitrogen, Cyanogen gas, 26.
  This compound, which is sometimes called the bicar-
buret of nitrogen, was discovered by Gay Lussac.   It
is readily made by heating the bicyanide of mercury,
carefully dried, in  a small  glass retort, with a good
spirit lamp.  In this operation the bicyanide of mercury
is resolved into its  elements, the cyanogen escapes as
a gas, and the mercury is sublimed; a dark brown mat-
ter like  charcoal remains in  the retort, which consists 
                        23

of the same ingredients as the gas itself.  It is scarcely
necessary to add the following diagram to illustrate the
operation.

    1  atom  r~— Cyanogen gas 26.
  Bicyanide J
      of   W  = Mercury 200.
   Mercury I
      254   . l_= Black matter or solid Cyanogen 26.

  Cyanogen, though a compound body, has a remark-
able tendency to unite with elementary substances; thus,
with oxygen and hydrogen  it forms highly interesting
and very peculiar acids.

        Cyanogen and Oxygen, Cyanic acid, 34.
  The existence of cyanic acid was first clearly demon-
strated by  Wohler.   It is  composed of one atom of
cyanogen  and  one  of oxygen.  It is made by mixing
ferrocyanate of potash with the peroxide of manganese,
in fine powder, and exposing them  to a low red heat.
The cyanogen  of the ferrocyanic acid receives oxygen
from  the manganese, and is  converted into the cyanic
acid, which then combines with the potash  and forms
the cyanate of potash.  This is then separated from the
impurities by boiling alcohol. The precise rationale of
the above  process has not  been  satisfactorily  deter-
mined, but the following diagram will illustrate some
of the changes. 
24

is ■a
O cS
2 Potash
Cy. iron
Cyanog.
Cyanog.
Hyd.
Hyd.
Oxygen.
Oxygen.
Oxygen.
Oxygen.
4 Protoxide of Manganese.
• 96"
Cyan. ac. = 34
Cyan. ac. = 34_
Water 9.
53
O «
— Water 9.
  The cyanic acid is then separated from the potash by
another  acid which is highly concentrated; the acid
vapours being collected in a receiver surrounded with
ice.  The cyanic acid is characterized by being con-
verted into the bicarbonate of ammonia on the addition
of water.  The following diagram will  illustrate this
change.
         (Carb. 8
1 Cyanic] Carb. 8
 Acid 34 \ Nit. 14
         I Ox.  8
         (Ox.  8
         Ox.  8
 3 Water] Ox.  8
   27   ) Hyd. 1
         Hyd. 1
         I Hyd. 1
22 Carb. ac.
22 CaTb. ac.
17 Amm.
a
  The above change is effected by simply boiling the
aqueous solution of the cyanate of potash.  It is obvious
from the above sketch that the hydrous cyanic acid
alone, which consists of one atom of real acid and one
of water, cannot undergo the same change as its aqueous
solution. 
              Cyanate of Ammonia, 60.
  The action of cyanic acid on ammonia is peculiarly
interesting.  The true nature and relations of this salt
were first  established by Dr. Wohler.   He found it to
be precisely identical in its composition with an animal
product called urea.  It may be prepared either by the
action of  aqua ammoniae on  the  cyanate of lead, or
when dry  ammoniacal gas is mixed with the vapour of
hydrous cyanic acid.  In this last process a white crys-
talline solid is formed, which is probably a dicyanate;
this gently heated gives off ammonia, and the cyanate
of ammonia remains, in which all  the properties of the
animal principle of urea may be recognised.  The fol-
lowing exhibition of the elements  which enter into the
constitution of the two substances,  will render the above
change obvious.
      Urea.                  Cyanate of Ammonia.
2 Carbon   = 12     ^        .,("1 Oxygen   =  8
                     Cyanic acid S a CaJfon    = H
2 Nitrogen = 28                C 1 Nitrogen  = 14
                      Ammonia  f 1 Nitrogen  = 14
4 Hydrogen =4         17     £ 3 Hydrogen  =  3
                       Water 9  $l Hydrogen  =  1
2 Oxygen  =16       vvaierj  £ x 0xygeri   =  8

              60                                60
  There are other acids formed by the union of oxygen
and cyanogen; one is the  fulminic or cyanic acid of
Leibig, and the two cyanuric acids of Wohler.
      Cyanogen and Hydrogen, Prussic acid, 27.
  The prussic or hydrocyanic acid was discovered by
Scheele.   It may be prepared by a  number of processes.
A good one consists in filling a glass tube, placed hori- 
26
zontally, with fragments of the bicyanide of mercury,
and then passing a current of dry sulphuretted hydrogen
gas slowly through it.  The instant the gas comes in
contact with the cyanide, double decomposition ensues,
and hydrocyanic acid and bisulphuret of mercury are
formed.
  One equivalent of the bicyanide requires two equiva-
lents of sulphuretted hydrogen for its complete decom-
position, and two  equivalents of hydrocyanic acid and
one of the bisulphuret  of mercury are obtained.  The
following diagram gives a view of the action that takes
place.
                              After decomposition.
                               —-27 Hydroc. Acid.
                                   27 Hydroc. Acid.
     Before decomposition.
           ("Hyd.   1
Sulphurett.  I Hyd.   1
  2K.^-aisuiph-i6
  17 + 2.    l_Sulph. 16
Bicyanide ofj Cyan. 26
mercury 252. < <^yan. 2b
          C Merc. 200
232 Bisul. Merc.
  The hydrocyanic acid obtained in this manner is very
strong and pure, and equal in weight, when carefully
collected, to about a fifth part of the  bicyanide em-
ployed.
  Another process is by heating bicyanide of mercury
in a glass retort with concentrated muriatic acid; the
hydrogen of the acid unites to  the cyanogen of the cy-
anide, and corrosive sublimate remains in solution, thus:
    2
Mur. acid
   74
J Hyd.
^ Chlo.
                  1
                  1
                 36
         LChlo. 36
    1    r Cyan. 26
Bicya. of< Cyan. 26
 Mercury CMer. 200
■= 27 Prus. acid.
•= 27 Prus. acid.
=- 272 Cor. Sub. 
27
  The vapour of prussic acid, as it rises  during the
above process, is always mixed with moisture and mu-
riatic acid, from which it must be freed.  It is highly
necessary in the preparation of prussic acid to avoid all
excess of muriatic acid, otherwise it resolves itself into
ammonia  and formic acid; the muriatic acid seems to
occasion this change by its affinity for ammonia. It will
at once be perceived that one atom of prussic acid and
three of water contain  the exact elements for forming
one of ammonia and one of formic acid, which  last is
composed of two atoms  of carbonic oxide and one of
water.
Prus.
   27
   f Carb. 6

aci Nit. 14
   iHyd. 1
    3
Water 27
14 Carb. ox
14 Carb. ox,
9 Water
   1
Formic
 acid
  37
= 17 Ammonia.
        Carbon and Hydrogen, Olefant gas, 14.
   This gas was discovered by the associated Dutch
Chemists.  It is prepared by mixing  one part by mea-
sure of alcohol with three of strong sulphuric acid in a
glass retort, and exposing the mixture to a gentle heat.
The retort should not be more  than  a third full, and
when only a small  quantity of the  gas is required,
half an ounce of alcohol with a proper quantity of sul-
phuric acid will be found quite sufficient. A little ether
is  formed  at first, and towards the end of the process,
sulphurous acid, carbonic oxide, and the bihydruret of 
28
 carbon (another compound of carbon and hydrogen) are
 disengaged; the mixture also becomes quite black from
 the deposition of carbon, and is very apt to boil over.
   To  understand the nature of the changes that take
 place in this process, it must be recollected that every
 23 parts, or one equivalent  of alcohol, is  composed of
 three parts of hydrogen (three equivalents) twelve of
 carbon (two equivalents) and eight of oxygen (one
 equivalent,) so that it may be regarded as a compound
 of one equivalent of water and one of defiant gas, for
 the different elements are present exactly in the propor-
 tions necessary to form these compounds.  The water
 then may be  said to combine with the sulphuric acid,
 while the defiant gas is disengaged; the new arrange-
 ment which the elements  of the alcohol assume  is re-
 presented in the following diagram.
     Before decomposition.        After decomposition.
         CHyd. 1---------______,14 defiant Gas.
          Hyd. 1------^^
 Alcohol) Hyd. \-. ^^^<
   23   \ Carb. 6 ^><C
          Carb. 6-^    ^^-^^
         LOx.   8--------------^9 Water.
  The olefiant gas disengaged  from each equivalent
 of alcohol at the commencement  of the process, often
 combines with  an equivalent of alcohol which is not
 decomposed,  forming one equivalent of ether,  which
 explains its appearance; the black colour which the
 liquid assumes  afterwards, and the  formation of bihy-
 druret of carbon arise from the elements of the alcohol
arranging themselves in a different manner, which will
be readily understood from the annexed diagram. 
29
     Before decomposition.         After decomposition.
        ("Hyd. 1-----__—--^ 8 Bihyd. of Carb.
          Hyd. 1
Alcohol J Hyd. 1
   23  "S Carb. 6-
        | Carb. 6 —             —6 Carb. precipit.
        LOx.  8------------—^ 9 Water.
  But no sooner is  the carbon precipitated than it be-
gins to react upon the sulphuric acid, taking one equi-
valent of oxygen from  it, and being converted into
carbonic oxide, while  the sulphuric acid becomes sul-
phurous acid in consequence of losing this proportion
of oxygen, a small  quantity of carbonic acid is also
formed towards the  end of the process.

  Light Carburetted  Hydrogen gas, or Fire Damp, 8.
  The true nature of this gas was first ascertained by
Dalton.  It  occuts  abundantly in nature, but there is
no convenient method of making it  artificially.   It is
composed of two atoms of hydrogen and one of carbon.
  The researches of  M. Faraday have enriched the
science of Chemistry by the discovery of several other
combinations of carbon and hydrogen.

       BORON, SILICON,  ZIRCONION.

  The three elementary bodies above named are analo-
gous in many respects to  carbon.  The combinations
which they form by uniting to the substances already
mentioned, do not require any particular illustration.

     PHOSPHORON OR PHOSPHORUS, 12.
  Phosphorur- was discovered by Brandt.  The method
now used of obtaining it from bones, was first proposed 
30
 by Scheele.   Calcined bones, of which phosphate of
 lime constitute nearly four-fifths, are reduced to powder
 and digested for some time in sulphuric acid; a slightly
 soluble sulphate of lime, and a soluble biphosphate of
 lime, are thus produced, which, on the addition of boil-
 ing water, are easily separated from  each other by fil-
 tration.  The biphosphate of lime is then decomposed
 by means of charcoal, the oxygen of the phosphoric
 acid forming with the  charcoal, carbonic  acid and the
 phosphorus escaping in a free state.
   The combinations of phosphorus with the substances
 already mentioned are  numerous, but the exact atomic
 constitution of these compounds cannot be considered
 as fully established; it is therefore expedient to repre-
 sent these combinations in the manner heretofore adopted
 in chemical works, till further experiments shall finally
 establish their exact constitution.
   The following table shows the composition of  the
 compounds of phosphorus with oxygen and hydrogen.

                         Phosphorus.    Oxygen.
 Phosphoric Acid,             12    +    16   =  28
 Pyro-phosphoric Acid,        12    +    16   =  28
 Phosphorous Acid,            12    +     8   =  20
 Hypo-phosphorous Acid,       24    +     8   =  32
                         Phosphorus.   Hydrogen.
 Proto-phosphuretted hydrogen, 12    +     2   =  14
 Phosphuretted hydrogen,      12    +     1   =  13

    Phosphoric Acid and Pyro-Phosphoric Acid, 28.
  These compounds afford an instance of a fact of great
interest in reference to the atomic theory, which is, that
two substances which differ essentially in their chemi- 
31
cal properties may be formed by the union of the same
ingredients in the same proportions; such  compounds
are said to be isomeric.
  Phosphoric and  pyro-phosphoric acid may be pre-
pared by burning phosphorus under a dry receiver of
air or of oxygen gas;  a white flaking powder  is pro-
duced, which is  unhydrous pyro-phosphoric acid; this
on exposure to the  air for some time absorbs moisture,
and become  phosphoric acid.  A  red heat converts
phosphoric acid  into pyro-phosphoric acid, and water
reconverts the latter into the former, which in a free
state only exists in solution.  Both these acids form
characteristic salts by uniting to the different bases.

               Phosphorous Acid, 20.
  This compound is generated in various ways.  When
sticks of phosphorus are exposed to the air in a funnel
they become oxidated,  moisture is absorbed,  and  an
oil-like liquid drops through  the funnel, which is the
acid in question.  Its salts are the phosphites.

             Hypo-phosphorous Acid, 32.
  This  compound was discovered by Dulong.  It is
produced by the action of water on the phosphuret of
barium; mutual decomposition ensues; the elements of
water uniting with different portions of phosphorus give
rise to the formation of three compounds, phosphuretted
hydrogen, phosphoric acid, and hypo-phosphorous acid:
the former escapes as a gas; the  two latter combine
with the baryta, generated by the oxygen of the water
and the barium.   The hypo-phosphate of baryta being
soluble, is easily separated by a filter from the insoluble
phosphate of baryta; sulphuric acid being then added 
32
to the hypo-phosphate  of baryta, sulphate  of  baryta
precipitates and the acid remains in solution.

                Oxides  of Phosphorus.
  A white crust is formed on the sticks of phosphorous
when they are kept for  some time under water, and a
red coloured matter often remains after its combustion;
both these substances are supposed to be oxides, but
their real nature has not been determined in a satisfac-
tory manner.

             Phosphorus and Hydrogen.
  Proto-phosphuretted hydrogen gas and phosphuretted
hydrogen  are the only compounds of these  two sub-
stances generally admitted, and much uncertainty still
prevails respecting their exact constitution;  we shall
therefore adhere to the old method of stating their com-
position.

        Proto-phosphuretted Hydrogen gas, 14.
  This compound was discovered by Sir H. Davy.   It
consists of one atom of phosphorus and two of hydrogen,
and is  made by heating  solid hydruretted phosphorous
acid in a close  vessel.  The chemical  changes which
give rise to its production are thus explained by Sir H.
Davy.   For every four atoms of phosphorous acid two
atoms  of  water are decomposed.  The six  atoms  of
oxygen unite with  three of phosphorus, forming three
atoms of phosphoric acid; while the remaining atom of
phosphorus attaches itself to  the two atoms of hydrogen
and forms  one atom of  proto-phosphuretted  hydrogen
gas.  These changes may be exhibited as follows: 
33
2 Phosphor, acid.
Phosphoric acid.
       '2 Phos
       Oxyg.
4 atoms Oxyg.
 Phos. Oxyg.
 Acid. | Oxyg.
       Phos.
       iPhos.
       (Oxyg.
2 atoms) Oxyg.
 Water \ Hydr.
       l^Hydr.  _—---         ^ Proto-phos. Hyd.
 Phosphuretted or Perphosphuretted Hydrogen gas, 13.
  This compound was discovered by Gengembre.   It
has been supposed to consist of one atom of phosphorus
and one of hydrogen.  It  is made  by heating small
pieces of phosphorus with  a  thick paste of recently
slaked lime.  Three compounds of phosphorus  are
generated—phosphoric acid, hypo-phosphorous acid and
phosphuretted hydrogen, all of which are produced by
the decomposition of the water and the combination of
its elements with different portions of phosphorus.

       SULPHURON OR SULPHUR, 18.

  This element exists  in  a pure state abundantly in
nature.  Its compounds with oxygen and hydrogen are
shown in the following table.
Hypo-sulphurous Acid,
Sulphurous Acid,
Sulphuric Acid,
Hypo-sulphuric Acid,

Sulphuretted Hydrogen,
Bisulphuretted Hydrogen,
Sulphur.		Oxygen.	
16	+	8 =	24
16	+	16 =	32
16	+	24 =	40
32	+	40 =	72
Sulphur		lydrogen.	
16	+	1 =	17
32	+	1 =	33
 
34
                  Sulphuric Acid, 40.
   This acid is said to have been discovered by Basil
 Valentine.  It is made by burning sulphur and nitre in
 a large leaden chamber, the floor of which is covered to
 the depth of several inches with water. The nitric acid
 of the nitrate of potash gives oxygen to a portion of the
 sulphur and converts it into sulphuric acid, which com-
 bines with the potash of the nitre and forms the sulphate
 of potash, while a greater part of the sulphur forms sul-
 phurous acid by uniting with  the oxygen in the air of
 the  chamber.  The nitric  acid, on losing a portion of
 its  oxygen, is converted  into the deutoxide of nitro-
 gen, which at the moment  of its separation unites to
 the  oxygen of the  air and becomes the  nitrous  acid.
 The gaseous compounds present in the leaden chamber
 are, therefore,  sulphurous  acid,  nitrous  acid, atmos-
 pheric air, and a little  watery vapour.  Trje sulphurous
 acid and the nitrous acid are now absorbed by the water
 in the bottom of the chamber.  The nitrous acid gives
 out two atoms of its oxygen to two atoms of sulphurous
 acid and converts them  into two atoms of sulphuric acid,
 thus resolving itself into  the  deutoxide of nitrogen,
 which from its levity rises into the air of the chamber,
 combines again with two atoms of its oxygen, and again
 becomes nitrous acid.  This then  descends again into
 the water, and converts two more atoms of sulphurous
 acid  into two of sulphuric, and again rises; and so on,
 until by the same process of combination  and decom-
position the whole of the sulphurous acid in  the water
is  converted into  the sulphuric acid.  Some of these
changes may be illustrated by the following diagram. 
35
Sulphate potash.
 Sulphurous acid.
-Sulphurous acid.
   1   ("Nitrog. -----------  ___^-Deutox. of Nit.
Nitrate   Oxyg.
Potash   Oxyg.
      <  Oxyg.
         Oxyg.
   3     Oxyg.
Sulph. ^Potash
         Sulphur
         Sulphur
         Sulphur
Atmospheric air.
  The above rationale was formerly given to the pro-
cess, and it is probable that much of the sulphuric acid
in the leaden chamber is  formed in this manner.   But
there is always a crystalline solid produced by the union
of nitrous acid, sulphurous acid, and watery vapour;
and most chemists imagine that it is the decomposition
of this solid by the water on the floor of the chamber
that the  sulphuric acid is produced.  Different views
have been taken of the constitution of this solid.  Gay
Lussac's opinion  appears the most plausible.  By the
mutual reaction of moisture, sulphurous acid and nitrous
acid, the crystalline compound is formed, which he sup-
poses  to consist of sulphuric acid, hyponitrous acid, and
water.  When  this solid falls into the  water of the
chamber  it is  instantly decomposed, sulphuric acid is
dissolved, and nitrous acid and the deutoxide of nitrogen
escape.   The nitrous acid thus set free, as well as that
produced by the deutoxide absorbing oxygen from the
air, is again intermixed with sulphurous acid and hu-
midity, and this gives rise to form a second portion of the
crystalline solid which undergoes the same change as
the first.   The production of the crystalline compound
p.s above  may thus be illustrated. 
36
   2
Sulph
Acid 64
   2
Nitrous
 Acid
        Sulph. 16.
        Oxygen 8
        Oxygen 8-
        Oxygen 8-
        Oxygen 8
        Sulph. 16
        Oxygen 8'
        Oxygen 8
        Oxygen 8
        Oxygen 8
        Nitro.  11
        Oxygen 8
        Oxygen 8
        Oxygen 8
        Oxygen 8
       JMitro.  14
Watery vapour---
Sulphur, acid 40""
'Sulphur, acid 40
sHyponit. acid 38
"Hyponit. acid 38
  Now when the crystalline solid drops into the water,
the sulphuric acid is absorbed, and the two atoms of
hyponitric acid undergo  decomposition, being resolved
into nitrous acid and deutoxide of nitrogen, as shown by
the diagram under the head of hyponitrous acid.

               Sulphurous Acid, 32.

  This acid seems first to have been noticed by Stahl.
It may easily be prepared by depriving sulphuric acid
of one atom of its oxygen.  Nearly all the metals, with
the aid of heat, have this effect; one portion of sulphuric
acid yielding  oxygen to the metal, and thus becoming
sulphurous acid, while the metallic oxide at the moment
of its formation unites with some of the undecomposed
sulphuric acid, which thus becomes a  sulphate.  The
best process is to place 'one part  of mercury and two of
sulphuric acid in  a glass retort, and then apply heat.
The changes are as follows: 
37
Sulphurous acid 32.
                        -Prot. mere. 208 "^Sulphate
                                        Y Protox.
Sul. acid  40------------------------J Mercury.
              Hyposulphurous Acid, 24.
  This acid was discovered by Gay Lussac.  It cannot
exist permanently in a free state.  It is procured by
digesting sulphur in a solution of the sulphite of lime
or any other sulphite.  In this process an atom of the
oxygen in the sulphurous acid unites  to the sulphur,
and thus produces 2 atoms of hyposulphurous acid; thus:
     1     rSul.  16—-^^^r^Hyposul. acid 24.
Sulphurous < Oxy.  8--------
  acid 32  C Oxy.  8—______^
Sulphur, ...  16----    ~"^~~ Hyposul. acid 24.
  It is remarkable that while the elements of hyposul-
phurous acid are in the ratio of 16 to 8,  its  equivalent
or atomic weight is not 24, but 48.  This is inferred
from the fact  that the quantity of this  acid required to
neutralize one equivalent of any alkaline substance is
48.  From this  it would seem that a single atom of
hyposulphurous  acid is formed of two atoms of sulphur
and two of oxygen.

              Hyposulphuric Acid, 72.
  This acid was  discovered by Gay Lussac and Welter.
It is  formed by transmitting a current  of sulphurous
acid gas through water containing  peroxide of manga-
nese in fine powder.  The manganese yields oxygen
to the sulphurous acid, converting one part of it into sul-
       n 
38
phuric acid and another part into the hyposulphuric
acid, both of which unite to the protoxide of manganese.
To  the  liquid,  after filtration, a solution of baryta is
added, which precipitates the protoxide of manganese
and forms an insoluble sulphate of baryta with the sul-
phuric acid, and a soluble hyposulphate with the hypo-
sulphuric acid.  The hyposulphate of baryta is then
decomposed by  a  quantity of sulphuric  acid, exactly
sufficient for precipitating the baryta, and the hyposul-
phuric acid is left in solution.  The following diagram
will illustrate some of these changes.
Hyposulph. acid 72-
3 atoms
 Sulph.:
 Acid.
Sulph. acid 40^\ m
       fSul. 16
        Sul. 16
        Ox.
        Ox.
        Ox.
        Ox.
        Ox.
        Ox.
       ISul,
2 atoms (Ox.
 Perox. j Ox.   8 -^                           I  g
 Mang. | Protoxide of manganese ....  36 J  f*
  88° (Protoxide of manganese.....36

             Sulphuretted Hydrogen, 17.

  This gas was first investigated by  Scheele.   It  is
prepared by adding liquid muriatic acid and the sulphuret
of antimony together and applying heat.  In this pro-
cess the water and the muriatic acid is probably decom-
posed, the hydrogen  combines with the sulphur of the
sulphuret, and escapes as sulphuretted hydrogen, while
the oxygen unites to the antimony and forms the pro-
toxide of antimony,  which probably attaches itself to 
3y
some undecomposed muriatic acid.
be illustrated thus:
These changes may
Sulphuret r Sul.
    of    j
Antimony (_ Ant.

         CHyd.
Water   <
         COxy.
Muriatic acid---
Sulphuret. hydrogen.
Ox. of Ant. J Mur. of
----------$ Antim.
  Some chemists imagine that in the above process
muriatic acid and not water is decomposed, and it is
doubtful which explanation is the true one; thus:
Sulphuret f" Sul.
    of    j
Antimony C Ant.
Mur. acid-
CHyd.

  Chi.
Sulphuretted Hyd.
Chloride of Antim.
  Sulphuretted hydrogen is also made by the action of
sulphuric acid on the protosulphuret of iron.  A reaction
takes place between  every nine parts of water (one
equivalent) and 44 (one equivalent) of the sulphuret of
iron, the  latter being composed of 16 of sulphur and
28 of iron.  The oxygen  of the water combines with
the iron of the sulphuret, forming oxide of iron, with
which one equivalent of the acid unites, converting it
into sulphate of iron which remains in solution, while
the sulphur and the hydrogen combine together to form
sulphuretted hydrogen.  The following diagram from
Reid is intended to illustrate the decomposition. 
40
 9 Water. S "^ J-----~^ 17 SulPh' Hydro"
          £ Ox.  8    ^^--~
 44 Sulph. C Sul. 16- ^\
   of iron. \ Iron 28-_____^__^-^
 40 Sulphuric ac.40      ~~~^~~^--76 Sulph. of Iron.
            Bisulphuretted Hydrogen,  33.
   This compound was discovered by Scheele.  It is
 made by  boiling together equal  parts  of slaked lime
 and flowers of sulphur, with five or six of water, when
 a deep orange-yellow solution is formed, which contains
 the hydrosulphuret of lime with an excess  of sulphur.
 This, on being gradually poured into a dilute solution
 of muriatic acid,  deposits  sulphur, and the sulphu-
 retted hydrogen instead of escaping  from the solution,
 unites with the  sulphur so as to form the bisulphuretted
 hydrogen, which  gradually subsides in the form of a
 semi-fluid matter like oil. From the facility with which
 this substance resolves itself into sulphur and sulphu-
 retted hydrogen,  its chemical history  has been  very
 imperfectly ascertained.
  The combinations of sulphur  with  the  other  sub-
 stances already mentioned do not fall under  our present
 plan.

 SELENION, 40, AND TELLURIUM, 32, (32-2.)

  The above mentioned elementary bodies occur in very
 small quantities in nature.   Selenion, or Selenium, as
it  is commonly called, was discovered in sulphur by
Berzelius, and  is  analogous  in many respects to that
body.  Tellurium was  found by Klaproth in an ore of
gold. 
41
    ARSENICUM OR ARSENIC,  38,  (37-7.)

   Arsenic  is found in nature, but it commonly occurs
 in combination with cobalt, from which it is separated,
 on account of its volatility, by merely heating the ore.
 This  process seems  first to have been practised  by
 Brandt.  The following is a view of the combinations
 of arsenic with oxygen and hydrogen.
                          Arsenic.  Oxygen.
 Arsenious acid,.....38   +  12 = l£ = 50
 Arsenic acid,.....38   +  20 = 2j = 58
                           Arsenic.  Hydrogen.
 ATsenuretted hydrogen, .  .  38   +  1$
 Solid arsenuretted hydrogen,  38+1

                 Arsenious Acid, 50.
   This is the compound which sublimes when the ar-
 senical ores are roasted, the oxygen of the air combining
 with the metal and producing the acid;  or, as it is often
 called, the  white oxide of arsenic.   Every student
 should be familiar with the methods used for detecting
 this  substance, as it  is frequently administered as a
 poison.  It  does  not fall within the plan of this little
 work to enter into all the details, but the following pro-
 cess is the most certain and the only necessary one that
 need be employed:—The fluids of the stomach in which
the poison is commonly lodged, are in the first place to
be freed from all  organic substances which  may inter-
fere with the action of the test to be applied.  This is
 readily done by boiling them with  successive portions
 of pure or distilled water, then filtering the solution, and
 addino- to it some acetic  or  muriatic  acid.  Through
       d2 
42
this liquid sulphuretted hydrogen  is to be passed; if
arsenious acid is present, even  in  exceedingly minute
quantities, a yellow  colour will be  produced, by the
formation of orpiment or the yellow sulphuret of arsenic.
This  is at first partially suspended, but on boiling the
fluid  to expel the free sulphuretted hydrogen it sub-
sides, and may easily be collected on a filter.   On dry-
ing the  sulphuret thus obtained, mixing it with  dry
fused carbonate of potash, and heating the mixture con-
tained in a glass tube, to redness over a good spirit lamp,
decomposition ensues, and  the arsenic is revived on the
cool part of the tube,  in the form of a metallic crust, of
an iron-gray colour externally, and of a crystalline struc-
ture internally.  A few particles of this crust placed on
red hot charcoal volatilizes as a white cloud, and gives
out an alliaceous odour.
  The following  diagram will illustrate one of the
changes which takes  place in the above process.

    Arsenious  (^Arsenic-----------"\
      Acid.    £ Oxygen   ?Water (Sulphuret of
  Sulphuretted C Hydrogen 5       ' f  Arsenic.
    Hydrogen. £ Sulphur-----------J

  Arsenic Acid.—This compound  was  discovered by
Seheele.  It is made by dissolving  arsenious acid in
strong nitric  acid, mixed  with  a  little muriatic, and
distilling the solution to perfect dryness.
  Arsenuretted Hydrogen.—This was also discovered
by Seheele.   It is prepared by digesting an alloy of tin
and arsenic in muriatic acid.
   Solid Arsenuretted Hydrogen was discovered by Davy
and Gay Lussac.  It is formed by the  action of wateT
on an alloy of potassium and arsenic. 
43
  Sulphureis of Arsenic.—There are at least two sulphu-
rets of arsenic, realgar and orpiment; both occur in the
mineral kingdom.  Realgar is composed of one atom
of arsenic and one of sulphur, and orpiment of one atom
of arsenic and one and a half of sulphur; it is therefore
a sesqui-sulphuret.

            TIN OR  STANNUM, 58.

  This metal has been known from the earliest times.
The only valuable ore of tin is the peroxide, from which
the metal is obtained by heat and charcoal.  There are
but two oxides of tin, and they are  thus constituted.
                         Tin.         Oxygen.
  Protoxide,  .   .  .  .  58 or 1 atom +  8 = 66
  Deutoxide,  .   .  .  .  58 or 1 atom + 16 = 74

  As both these oxides have  some acid powers, they
have been called the stannic and the stannous acids.

            POTASSIUM, 40,  (39-15.)

  Potassium, the metallic base of potash, was discov-
ered by Sir H. Davy, while investigating the  electro-
chemical powers of the galvanic battery.  It is com-
monly prepared  by the action of iron or  charcoal on
pure potash at a high temperature.  The theory of both
processes is very simple.
   p    ,  C Potassium 40
    ° M  I Oxygen    8 7    36 protoxide of iron.
   Iron.....28 3
   Perhaps the sesqui-oxide of iron may be formed in
this operation, and then every two  atoms of that metal 
44
 would decompose three of potash.  When charcoal
 is used, the oxygen from two parts of potash unites
 with the charcoal and produces carbonic acid; thus:
            ("Potassium 40
       2   J Potassium 40
     Potash^ Oxygen    8^
            LOxygen    8 C= 22 Carbonic acid.
     Carbon  .   .   .   .  6 J
  The best process is  to decompose the potassa by a
 mixture of iron  filings and charcoal.
  Potassium unites to oxygen in two proportions, thus:
                        Potassium.        Oxygen.
 Protoxide of Potassium,    40 or 1  atom  +  8 = 49
 Peroxide of Potassium,    40 or 3  atoms + 24 = 64

  The compounds  of potash or the protoxide of potas-
sium, with the  acids already mentioned, are many of
 them highly interesting.

               Nitrate of Potash,  102.
  This important salt,  called in common nitre or salt-
petre, occurs in nature;  but it is commonly prepared by
decomposing  the nitrate of lime,  an abundant natural
production, with carbonate of potash  or pearl  ashes.
The following is the rationale.

Nitrate JNitric ac- 54----------prNit. of potash 102
of lime i T .
  82   LLime

CaJ. oflPotash
 potash |^Carb>  ac> Q2 _         \ Carb> Qf ]jme 50
 
45
               Carbonate of Potash, 50.
  There are three salts formed by the union of carbonic
acid uniting in different proportions with potash.

Carbonate of Potash,       48  or 1 atom + 22 = 70
Bicarbonate of Potash,      48     „     + 44 = 92
Sesqui-carbonate,           48     „     + 33 = 81

               Sulphate of Potash, 88.
  This  salt may be prepared by neutralizing the  car-
bonate of potash with sulphuric acid, and is easily ob-
tained from the residuum of  the distillation of nitric
acid, dissolving it in water and adding sub-carbonate of
potash till the excess of acid is completely neutralized.
The solution is then evaporated to expel part of the
water, and small crystals  of the  sulphate are deposited
on cooling.  Carbonate of lime is occasionally employed       »
instead  of carbonate of potash to remove the excess  of
acid, continuing to  add it to the solution of the bisul-
phate as long as  any effervescence takes place.   The
following diagram shows the  action that takes place,
supposing all the potash to be in  the state of bisulphate.
   Before decomposition..
   128  r Potash    48
Bisulph.^ Sul. acid 40
 potash. C. Sul. acid 40
50 Carb. C Carb. ac. 22
of lime. £ Lime    28

             Sulphuret of Potassium, 56.
  It may be obtained  pure by  passing hydrogen gas
over the sulphate of potassa; four atoms of water and
one of the sulphuret of potassium will thus be generated.
After decomposition.
  .88 Sulph. potash.
22 Carbonic acid.
68 Sulph. of lime. 
46
 Sulphate J Oxygen
of Potash \ Oxygen
fpotasslum 40 } SulPhuret of Potassium!
Hydrogen*
  gas 4
 Oxygen
.Oxygen
"Hydrogen
 Hydrogen
 Hydrogen
.Hydrogen
U atoms of Water - - - 36
SODIUM,  24,  (23-3.)
  This element was discovered by Sir H. Davy.  It is
obtained in the same manner as potassium.  There are
two oxides, which are thus constituted:
Protoxide of Sodium,
Peroxide of Sodium,
Sodium.          Oxygen.
  24 or 1 atom  +  8 = 32
  48 or 2 atoms + 24 = 7"2
  The compounds of soda or  the protoxide of sodium
are very analogous to those of potash.

                 Carbonate of Soda.
  There are three salts formed by the union of carbonic
acid with soda.
Carbonate of Soda,
Bicarbonate of Soda,
Sesqui-carbonate,
Soda.       Carbonic Acid.
 32 or 1 atom + 22 = 54
 32     "     + 44 = 76
 32     "     + 33 = 65
                 Phosphate of Soda.
  This is a very valuable salt. It is prepared on a large
scale by neutralizing the biphosphate of lime, procured
by the action of sulphuric  acid on calcined bones, with 
47
the carbonate of soda.  The excess of phosphoric acid
in the biphosphate combines with the soda of the car-
bonate and remains in solution, disengaging carbonic
acid with  effervescence, while the phosphate of lime
having now lost its excess  of acid becomes  insoluble
and is precipitated.  In the following diagram repre-
senting the action that takes place, two equivalents of
acid are supposed to be combined with one of lime in
the biphosphate.

Carbonate of C Carb. acid 22—22 Carbonic acid.

RinvltL.   C P°^- a°id 28 } 60 PhosPhate of Soda-
Biphosphate   N phog acid 2Q J
   of Lime    ) ■*.   '     „„ > 56 Phosphate of Lime.

   The biphosphate of lime, however, is generally pre-
pared with a much greater excess of acid, and every
additional equivalent  which it  contains  enables it to
decompose another equivalent of the carbonate of soda.
The latter ought to be added till the solution can render
a test paper green, as a slight excess of alkali favours
the crystallization.  The solution is filtered to separate
the phosphate of lime, and evaporated afterwards till a
pellicle appears on its surface, when it may be set aside
to crystallize.—See Reid.

                Sulphate of Soda, 72.
   This is  the common glauber salt.  It is procured in
large  quantities as a residue in the process for forming
muriatic acid, which consists in adding sulphuric acid
to chloride of sodium. The following diagram exhibits
the chemical  changes. 
48
 1 Sulphate rHydrog. 1---------T^87 Muriat- acicl.
 of Water < Oxygen  8\   ^^^^
     49    C Dry ac. 40 O^C
 Chloride of C Chlor. 36 ''^^^x.
 Sodium 60 \ Sodium 24------—^72 Sulph. Soda.

 LITHIUM 10, BARIUM 69, (68-7,) STRONTIUM
                    44, (43-8.)

  These elementary bodies possess many interesting
 characters, but it does not fall within our plan to notice
 them particularly.

              CALCIUM, 20, (20-5.)

  The existence  of calcium, or the  metallic base of
lime, was perhaps first demonstrated by Dr.  Seebeck.
There are two oxides of calcium.
                         Calcium.        Oxygen.
Lime, or protox. of Calcium,  20 or 1 atom + 8 = 28
Deutoxide of Calcium,       20    „     +16 = 36

  The combinations of lime  with some of  the acids
form a very extensive and important class of mineral
substances.
  Nitrate of Lime.—This is a very abundant natural pro-
duction in the  lime-stone caverns  in the western parts
of the United States, where it occurs in connexion with
the nitrate of potash.
  Carbonate of Lime.—This  occurs  in nature under a
number of crystalline shapes. It forms extensive moun-
tainous masses, and constitutes a large part of the solid
crust of the earth.
  PhospJiate of Lime.—This salt exists  in bones  and 
49
the solid parts of animals, in the proportion of 86 per
cent.
  Sulphate of Lime.—This is found abundantly in the
mineral kingdom, and is  known in the arts under the
name  of gypsum, selenite, and alabaster.

            MAGNESIUM, 12, (12-7.)

  Magnesium, the base of magnesia, was first fairly
produced by M. Bussy, by the action of potassium on
the chloride of magnesium.
  Magnesia is the only known oxide of this metal—it
is prepared by exposing the carbonate of magnesia to an
intense heat, by which the carbonic acid is expelled.
  Carbonate of Magnesia  is  obtained by decomposing
the sulphate of magnesia with carbonate of potash—
double decomposition ensues, which will be readily
seen as follows:
  Sul. of C 20 Magnesia---------- ~\
   Mag. (_ 40 Sul. Ac."> Sulphate  ( Carbonate
  Carb.  C 48 Potash 3 Potash 88 f Magnesia 42
  of Pot. 122 Car. acid-----------)
  Sulphate of Magnesia or Epsom  salt, occurs often in
mineral springs;  but it is made on a large scale by the
action of dilute sulphuric acid or magnesian earths.

  ANTIMONIUM  OR ANTIMONY, 64, (64-6.)
  This  metal  is found native; but all the antimony of
commerce is derived frorri" the sulphuret.  There are at
least three oxides which appear to be  constituted as
follows:
^
*fcui
j &  no  oo
^■4?«^G 
50
                      Antimony.        Oxygen.
  Protoxide   -   -  -  -  64 or 1 atom + 12 = 76
  Deutoxide   -   -  -  -  64  -  -  -  + 16 = 80
  Peroxide    -   -  -  -  64  -  -  -  + 20 = 84

  Protoxide of Antimony.—This is made by boiling the
sulphuret in muriatic acid.   After the sulphuretted hy-
drogen produced by this process, escapes, the residue is
thrown  into water, and a white curdy precipitate falls,
which is the oxide in question, united perhaps to a little
muriatic acid.  This  by digestion  with carbonate  of
potash, yields the oxide in a state of purity.   The prin-
cipal chemical changes we have already explained un-
der sulphuretted hydrogen.   The protoxide of antimony
appears to be the active ingredient  in the  medicinal
preparations of which antimony forms a part.
  Deutoxide of Antimony or Antimonious Acid.—This
is generated when antimony is burnt in the air, or when
the sulphuret is  exposed to  a high heat—in this last
case,  sulphurous  acid and protoxide  are first formed;
but on continuing the roasting the acid is  driven off—
the oxide gradually absorbs oxygen  and passes into the
deutoxide.   The  following sketch will illustrate some
of these changes, the oxygen being derived from the
air:

                        js      /Deutoxide of
      Sulphuret of  r Antimony 3  Antimony
      Antimony    /Sulphur   ")c .  ,
              *    'Ox/gen   1^7™
                     Oxygen  3   ACld
  The  antimonious acid combines in definite propor-
tions with alkaline substances, and forms the salts call-
ed antimonites. 
51
  Antimonic Acid or the Peroxide of Antimony.—This is
prepared by digesting the metal in  strong citric acid,
expelling the excess of acid by heat, and throwing the
solution into water.  With alkalies this acid forms the
antimoniates.
  Antimony and Sulphur.—These elements combine in
several  definite proportions.  The  native  sulphuret,
from which the metal is obtained by heating that mine-
ral with iron filings, is a sesqui-sulphuret, consisting of
two  atoms of antimony and three   of  sulphur.  The
pharmaceutic preparations called the glass, the liver,
and the crocus of antimony, are for the most part com-
posed of one atom of the sesqui-oxide  and two of the
sesqui-sulphuret,  but owing to the  manner in which
they are prepared, their constitution is not uniform.
  When sulphuret of antimony is boiled in a  solution
of potash or  soda, a liquid is obtained which  deposits
after  cooling the kermes mineral, called so from its re-
semblance in colour to a reddish insect named kermes.
When an  acid is added to this solution a still farther
precipitate is produced, which is called the  golden sul-
phuret of antimony.   Several opinions  are entertained
as to the nature of these  precipitates.   The following
diagram will illustrate the first part of the  above pro-
cess as given by Berzelius—when sesqui-sulphuret  of
antimony is boiled with potash:

2 Sesqui-sul. C 2 Antimony-------
of Antimony \ 3 Sulphur  ") Sulphuret .
     3       C 3 Potassium 3 Potassium f    f". "t
   Potash    I 3 Oxygen-------------)   0I AIU'

  The liquid is now supposed to contain the  sesqui-
oxide of antimony and the sulphuret of potassium, to- 
                         52

 gether with some undecomposed potash and the sul-
 phuret of antimony.   The sulphuret of potassium then
 unites with undecomposed sulphuret of antimony, and
 the oxide of antimony with undecomposed potash, and
 both compounds are dissolved by hot water thus:

 Potash             ~) Sesqui-oxide of Antimony and
 Oxide of Antimony  3   Potash
 SulphurefPotassium") Sesqui-sulphuret of Antimony
 Sulphuret Antimony 3   and Sulphuret Potassium

   As the solution cools the sesqui-sulphuret of antimo-
 ny subsides, simply because the solvent power of the
 sulphuret of potassium, with which it was united, is
 thereby  diminished, and a variable quantity of potash
 and sesqui-oxide of antimony also falls with this deposit.
 This is the kermes, and is composed of
   Sesqui-sulphuret of Antimony,
   Sesqui-oxide of Antimony,
   And Potash.
   The cold solution still contains a double sulphuret of
 antimony and potassium and the  sesqui-oxide of anti-
 mony united to potash—on adding sulphuric acid, the
 sulphuret of potassium, by the decomposition of water,
 is converted into potash and sulphuretted hydrogen,
while the hydrated sulphuret of antimony and the oxide
 of antimony, which is also separated by the acid from
its potash, are thrown down either in combination or in
mixture with each other.  This is the golden sulphuret,
differing  from  the kermes, in the absence of potash,
and containing more oxide of antimony.  The following
sketch will assist  in recollecting these changes: 
53
Sulphuric acid----
Potash-----------

w*'«   {%$.
Sulphuret TPotas.
of Potas-J Sulph.
sium  and j Sulph.
Antimony ^.Anti.
Oxide of Antimony

  On the preceding explanation the metallic sulphuret
is supposed to exist as such in solution, and the com-
pounds are not regarded as sesqui combinations.  This
is done merely for the sake of brevity.
  Phosphate of Antimony and Lime.—This preparation
is called pulvis antimonialis, or James' powder.  It is
formed by heating strongly, in an open vessel, one part
of sulphuret  of antimony and two parts of hartshorn
shavings; the heat drives off the sulphur from the sul-
phuret, and the animal matter from the shavings;  the
antimony, by absorbing oxygen  from  the air,  passes
into the deutoxide, and thus unites to the phosphate of
lime of the hartshorn shavings.   A better way to form
this pharmaceutic compound is to add together in proper
proportions calcined bones and protoxide of antimony.
  Tartrate of Antimony and Potash.—This compound
has been long known in the materia medica under  the
name  of tartar emetic. It is made by boiling the pro-
toxide of antimony with a  solution of the bitartrate of
potash.  It is composed of
  Tartaric acid,        66 + 2 = 132 or 2  atoms.
  Oxide of antimony,  76 + 2 = 152 or 2  atoms.
  Potash,     -    -    -    -    48 or 1  atom.
  Water, -    -     -    9 + 2= 18 or 2  atoms.
       e2
------°) Sulphate
------C   of
Potash S Potash.
Sulphuretted Hyd.
J Hyd. Sulph. and
3 Ox. of Antim. 
54
   Tartar  emetic is decomposed  by many reagents;
 thus alkaline substances, from their superior attraction
 for  tartaric acid, throw down the oxide of antimony.
 Sulphuretted hydrogen precipitates the orange sulphuret
 of antimony.   A strong decoction of tea, an infusion of
 gall nuts, and other similar astringent solutions, form
 with it a dirty-white precipitate, which is  regarded as
 a compound of tannin and oxide of antimony.   This
 combination is inert, and therefore a decoction of cin-
 chona bark is a good antidote to tartar emetic.
   The best method of detecting  antimony in mixed
 fluids, as when tartar  emetic is mixed with articles of
 food, is first to digest them in water acidulated with
 muriatic or tartaric acids; the former coagulates any ani-
 mal principle  which  may  be  present, and the latter
 gives complete solubility to all precipitates formed by
 reagents with tartar emetic, except that caused by the
 sulphuretted hydrogen.   Through the  filtered liquid
 sulphuretted hydrogen is to be passed, when an orange-
 red precipitate is produced,  the sesqui-sulphuret of an-
 timony.   Its colour is so peculiar that it cannot readily
 be mistaken for that of any other sulphuret.  But to
 remove all doubt, put this  sulphuret when  dried in a
 glass tube, placed horizontally; transmit through it a
 current of hydrogen gas; the sulphur is then carried off
 as sulphuretted hydrogen,  and metallic antimony re-
 mains.
   In its  solid state, tartar emetic  may be reduced by
placing it on charcoal and heating it with a blowpipe
flame; it first decrepitates, then chars, and quickly small
shining globules  like quicksilver will be found in the
mass. 
55
                 CHROMIUM, 28.

  This metal was discovered by Vauquelin.  It unites
to oxygen in two proportions, forming a green oxide
and a red acid;  the emerald owes its colour to the pre-
sence  of the first, and the ruby to that of the second.
The chromate of potash, from which all the compounds
of chromium may be obtained, is  made by heating to
redness the native oxide of chromium and iron, impro-
perly called the chromate of iron, with an equal weight
of nitrate of potash, by which means  chromic acid is
formed; this acid then combines with the potash of the
nitre.
  Bichromate of Potash.—This beautiful salt is prepared
in large quantities at Baltimore for the purposes of the
arts, by acidulating the neutral chromate with sulphuric
or acetic acid.
  Several fatal  cases have occurred of poisoning with
the saturated solution of this salt.  Professor Ducatel
recommends as  an antidote the exhibition of carbonate
of soda or potash, which neutralize the excess of the
acid to which the active agency of the salt is principally
to be ascribed. The presence of chromate or bichromate
of potash in solution may be recognised by adding to
one portion the acetate of lead, and to  another portion
the nitrate of silver; the first causes a rich yellow and
the other a deep red or purple precipitate.   Any of the
chromates may  be known by boiling them in  muriatic
acid mixed with alcohol;  in  this process the  chromic
acid is at first  set  free and then decomposed, a green
muriate of the oxide of chromium being generated. 
56
 MANGANESIUM OR MANGANESE, 28 (27-7.)

   This metal was discovered by  Seheele and Gahn.
 It has a strong affinity for oxygen, and combines with
 it in the following proportions.

 Protoxide,           28+8     or    1  + 1 atom
 Sesqui-oxide,         28 +  12     „    2 + 3 atoms
 Peroxide,            28+16     „    1 + 2  „
 Red oxide,           28 +  10.66  „    3 + 4  „
 Varvacite,           28+14     „    4 + 7
 Manganesious acid,   28 +  24     „    1  + 3
 Manganesic acid,     56 +  56     „    2 + 7

   Of all these compounds the peroxide is perhaps the
most  important.   This is the substance which occurs
in commerce under  the  name of  the black oxide of
manganese.  It is  found abundantly in nature in large
amorphous masses, and sometimes  in  minute prisms,
radiating in groups from  a centre.   It is used for the
purpose of obtaining chlorine and oxygen.
  When the peroxide of manganese  is heated to redness
with  its own weight of nitre, a  compound is formed
called the mineral  camelion, which, when dissolved in
water, undergoes several changes of colour.  The green
colour is attributed to the manganesite of  potash and
the red to the manganesate, which salts  are formed
during the process.

MOLYBDENUM,  48,  (47-7,) TUNGSTENUM,
  100, (99-7,) COLUMBIUM, 185, TITANIUM 24
  (24-3,) URANIUM, 217.
the five metallic elements above noticed, little 
57
 need be said.  They occur rarely in nature, combined
 with other substances.  All of them unite with oxygen
 and form peculiar acids; most  of these combinations
 are, however, but very imperfectly understood.

             AURUM  OR GOLD, 200.

   This element has been known and prized from the ear-
 liest ages of the world, for few metals combine so many
 useful properties.  It has  always been found pure, or
 united in its metallic state with other bodies.  With
 oxygen it seems to unite in several proportions, but the
 chemical history of these  compounds is as yet  very
 imperfect.   Berzelius thinks  there are  three oxides.
 His protoxide  is obtained  by decomposing the proto-
 chloride of gold by pure potash; it is of a dark green
 colour.   The deutoxide is  purple, and  is produced by
 the  combustion of the  metal.   The peroxide is pre-
 cipitated by the alkalies  from  the solution of gold,
 combined with  muriatic acid.  It is composed of one
 atom of gold and three of oxygen, and is  the only  well
 ascertained compound of these  two bodies; as it has
 acid properties  it is called the auric acid.
  When the auric acid is kept for some hours in strong
 ammonia ■a  fulminating compound is formed, the ele-
 ments of which are in the  ratio  of- one atom of gold,
two of nitrogen, six of hydrogen, and three  of oxygen.
Dumas, who analyzed this  substance, supposes these
elements are arranged so as to form a hydrated nituret
of gold, united  to ammonia.  The following diagram
will explain his ideas on this subject. 
58
1 Auric
 Acid
Ammonia TT  ,
         I Hyd
         I Am.
Nit. of gold\   =
9 Water
9 Water
9 Water
an


Is
 n
      PLUMBUM OR  LEAD, 104, (103-5.)

  Lead is one of the earliest metals known.   It occurs
in nature in several combinations, but that with sulphur
is by far the most abundant.  It is from this ore, called
galena, that  metallic lead is  extracted, either by heat
alone, or by the combined action of heat and iron filings.
This last process may be thus represented:
1 Sulphuret C Lead   104
of Lead 120 I Sulphur, 16-
Iron,.....,28.
44 Sul. Iron.
  Lead has  three degrees of oxidation, and its  oxides
are constituted as follows:
                 Lead.         Oxygen.
  Protoxide,     104 or 1 atom   8  yellow oxide.
  Sesqui-oxide,   104    „      12  red oxide.
  Peroxide,      104    ,,      16  brown oxide.

  The protoxide of lead is the base of all the salts of
lead.   Many of these are poisonous—the  carbonate
seems to be the most virulent.  The best method of
detecting them in suspected fluids is  the sulphuretted
hydrogen, which throws  down  the black sulphuret of,
lead;  this being collected on a filter and washed, is to 
59
be digested in dilute nitric  acid until  the black colour
disappears.   The solution  of the  nitrate  of lead thus
formed is to be dried in a watch glass to expel any ex-
cess of nitric acid, and the residue  is to be dissolved in
cold water.  On dropping into this liquid hydriodate of
potash, the fine  yellow iodide  of lead will appear.
The last step in the above process may be represented
as follows:

Nitrate of5"Jfad  10i          —^= Iodide Lead.
   Lead  ; 0xygen 8 ^        /
 u A ■  >SU; aC' 5a l^<^~----102 Nit. Potas.
 Hydrio- CPotass. 48 \^^\^
  date of < Iodine \%6/   .   ^~~\
  Potash CHydrog. 1------------r=,»9 Water.

   The  sesqui-oxMe, or  red lead,  is employed in the
arts as a paint and in the manufacture of glass.
   Carbonate of  Lead.—This  is the  ceruse or white
lead of commerce.  It may be  prepared by adding  a
solution of carbonate of potash to one of nitrate of lead.
On a large scale it is formed by exposing sheet lead to
the vapour of vinegar.
   Phosphate of  Lead may be obtained by  adding the
phosphate of soda to the nitrate  of lead.
   Sulphate of Lead is  formed by mixing  sulphate  of
soda with  a solution of nitrate of lead.
   Chromate of Lead is produced by adding chromate of
potash to nitrate of lead.  The following diagram will
illustrate this and the cases of double decomposition
hinted at above. 
60

            Nitrate potassa.
                                     Chromate lead.

             FERRUM,  OR IRON,  28.

   This metal has been  known from time immemorial.
 Iron has a powerful affinity for oxygen; when moisture
 is present in the air it rusts, or oxidates with great ra-
 pidity.   There are but two definite compounds of these
 two bodies, which have the following constitution:
                        Iron.        Oxygen.
     Protoxide,           28   or 1 atom  8 = 36
     Sesqui-oxide,        28      „      12 = 40

   The black oxide which was formerly supposed to be
the protoxide of iron, has been proved to consist  of the
protoxide and sesqui-oxide, united together in propor-
tions that are very variable.  In studying the metallic
oxides it is necessary to distinguish those oxides which
are formed by the direct union of oxygen and a metal
from those produced by the union of two oxides with
each other, and which seem to be allied to salts  rather
than to  oxides.  The black oxide of iron furnishes an
example of  this sort of combination.   The protoxide
and the sesqui-oxide both form salts by uniting to  acids.
The protoxide is the base of the native carbonate of iron
and of the green vitriol of commerce. The black  oxide
is  often called magnetic iron  ore, and  it is principally
Nitrate rfCNitric.acid
  Lead   C Ox. of lead

™     .  r Potassa
Chromate)
 Potash  >Chrom>ac<
 
61
this compound which supplies the vast demands for
iron.
   Carbonate of Iron may be obtained by dissolving 144
grains of the crystallized carbonate of soda and pouring
the solution into an ounce of water in which 139 grains
of the crystallized green Sulphate of iron have been
dissolved, collecting the precipitate on a filter.   The
reaction that takes place is represented in the diagram,
the salts being mixed in equivalent proportions, making
allowance for the water of crystallization.
    Before decomposition.             After decomposition.
Carbonate *s Soda     32—    ~^Z'72 Sulph. of Soda.
  of Soda £Carb.ac<22

Snlphate  C^ulp. ac. 40
  of Iron  £ ox. Iron 36_      ^ 58 Carb. of Iron.
   The sulphate of soda remains  in solution, and the
precipitated carbonate is washed  on  a  filter with hot
water which has been boiled to expel the  air it usually
contains.  It  soon  attracts  oxygen from  the  air, and
assumes the same appearance as the rust of iron, losing
also part of its carbonic acid.—See Reid.
   Sulphate of Iron is prepared in large quantity for com-
mercial purposes by exposing the native  sulphuret  of
iron to air and moisture, the iron being converted into
an oxide and the sulphur into sulphuric acid by attract-
ing oxygen.  On the small scale it may be prepared by
mixing 6 parts of iron with 10 of sulphuric acid and 60
of water, evaporating the solution  in a glass or earthen
vessel, after the  effervescence arising from the  disen-
gagement of hydrogen gas has ceased, till a rod dipped
 
62
into it presents appearances of crystallization  when
held in the air.  The solution may then be filtered, and
green crystals of the sulphate will be formed as it cools.
The rationale of the process is given under Hydrogen.

                 Iron and Cyanogen.
  Iron unites to cyanogen and forms the base or radical
of a very interesting  hydracid, called  the hydro-ferro-
cyanic acid. The base of this compound has never been
obtained in an insulated state, but it is composed of
Cyanogen, 3 atoms ")    ? C Cyanogen,       2 atoms
Iron,      1 atom 3     L Cyanide of Iron,  1 atom
  The acid itself consists of one atom of the radical and
two of hydrogen.
  Hydro-ferrocyanic acid  is  obtained by adding sul-
phuric acid to  the hydro-ferrocyanate  of  barytes; sul-
phate of barytes precipitates, and the hydro-ferrocyanic
acid remains in solution.
  Hydro-ferrocyanate  of baryta is prepared by digesting
Prussian blue with a  solution of pure baryta.
  Prussian blue, or the hydro-ferrocyanate of the peroxide
of iron, is made by mixing  the hydro-ferrocyanate  of
potash with a salt of the peroxide of iron.
  Hydro-ferrocyanate  of potassa, which may be  consi-
dered as the parent of all  hydro-ferrocyanates, is pre-
pared on a large  scale in the arts, by igniting dried
blood or other animal matter, such as hoofs and horns,
with potash and iron.  By the mutual reaction of the
elements of these substances, ferrocyanide of potassium
is produced, consisting of one atom of ferrocyanogen,
or the radical  of the hydro-ferrocyanic acid, and two
atoms of potassium.  When  ferrocyanide of potassium 
63
is dissolved in water, a solution of the hydro-ferrocyanate
of potassa is formed by the decomposition of the water;
two atoms of hydrogen uniting to the ferrocyanogen
and forming one atom of hydro-ferrocyanic acid, while
two atoms of oxygen unite to the potassium.  The fol-
lowing diagram will illustrate this change:"
 Ferrocya- C Ferroc.-------------—^Hydroferro- '
  nide of < Potass, v         ^/     cyanic acid
Potassium C Potass. ^v//^

           ("Hydro. •'/xX.                   ^
     2    J Hydro. /    \\.
   Water  \ Oxyg.----'■-------^Potash
           LOxyg.-------------—^-Potash

       CUPRUM,  OR COPPER, 64, (63-2.)

   This is one of the ancient metals.   It occurs native,
often in very large masses, but the principal part of the
copper of commerce is derived  from the sulphuret.
With oxygen copper combines in at least two propor-
tions, and they are constituted as follows:
                 Copper.      Oxygen.
     Protoxide,     64   +   8 = 72 red oxide.
     Peroxide,      64   +   16 = 80 black oxide.
   Both these compounds are found native; the red oxide
is worked for the metal, and is a valuable ore, at Som-
merville, in New Jersey.
   Sulphurets of Copper.—These compounds are the cop-
per glance and the copper pyrites of mineralogists; from
the first the metal is generally extracted.
   Carbonate of Copper.—This forms the beautiful green
mineral called malachite.  The paint named verditer is
also a carbonate. 
64
   Sulphate of Copper, or Blue Vitriol.—It is prepared in
 the arts by roasting the native sulphuret so as to bring
 both its elements to a maximum of oxidation.  It con-
 tains two atoms of sulphuric acid and one of the perox-
 ide of copper.
   The  best* method of detecting copper  in suspected
 fluids is to pass into them sulphuretted hydrogen. The
 black  sulphuret of copper precipitates, which is to be
 collected  and heated to redness  to carbonize  organic
 matter, and then  digested  with a little nitric  acid.
 Sulphate of copper is thus formed, which, when dried
 and diluted with water, is rendered deep blue by ammo-
 nia.  The following diagram will explain the chemical
 changes in the first part of the above process, supposing
 that the nitric acid is digested on the bisulphuret of
 copper.
 1 Bisulph. C 2 Sulph_____---—^ 2 Sulphuric ac.^j nS
 of Copper £ Copper  -^^^"^                Lg£
          ("6 Oxyg. — \^                ffv
     3     | 2 Oxyg.---------— Deutox. copper J •  £?
   Nitric  -^ 1 Deutoxide of Nitrogen.
   Acid   I 1 Deutoxide of Nitrogen.
          LI Hyponitrous acid.
   Albumen  is the  best antidote to administer in cases
 of poisoning with copper.

      MERCURIUM,  OR MERCURY, 200.

  Mercury is  distinguished  from all other metals by
being fluid at the ordinary temperature of the  air.  It
is found native in all quicksilver mines, along with the
sulphuret, which is the common ore.  From this ore the
mercury is extracted by heating it with iron filings. 
65
Bisulph. of Merc. 7 Mercury 200
 or Cinnabar, 232 3 2 Sulphur 32 "> 88  Proto-sulpnuret
2 Iron,    -    -    -    -  56 3      of Iron.

  Mercury unites  to oxygen in two proportions, and
the oxides are thus constituted:
                 Mercury.      Oxygen.
    Protoxide,    200 +  8 = 208 black oxide.
    Peroxide,     200 + 16 == 216 red oxide.
  The peroxide of mercury, or  red precipitate, is  com-
monly prepared by dissolving the metal in nitric  acid,
and exposing the  salt so formed to a temperature just
sufficient to expel the whole of  the acid.  The oxygen
in the protoxide of mercury is very feebly united to the
metal, for it  resolves itself into fluid mercury and the
red precipitate, even when exposed to the light.  This
change may be shown as follows:

              ("Oxygen    8}
  2 Protoxide J Oxygen    8 C216 Red Precipitate.
   of Mercury ) Mercury 200 j
              LMercury 200

  Bicyanide of Mercury.—This compound is prepared
by boiling pure hydro-ferrocyanate of the peroxide  of
iron with the peroxide of mercury.  In this process Dr.
Turner remarks that the oxygen  of the oxide of mercury
unites to the hydrogen  and the iron of the hydro-ferro-
cyanic acid, while the metallic mercury combines with
the cyanogen.  The brown matter which falls, he ob-
serves, is the peroxide of iron.  It  appears from the
following diagram that cyanide  of iron, as well as per-
oxide of iron, must remain undecomposed. 
66
Bicyanide Merc.
2 Water.
     1      ("1 Peroxide Iron.
Hydro-ferro-J  1 Cyanide Iron.
 cyanate of  ]  2 Cyanogen
 Perox. Iron \J2 Hydrogen s^

1 Peroxide  C 1 Mercury
 of Mercury £ 2 Oxygen
  Bisulphate of Peroxide of Mercury is prepared by boil-
ing to dryness sulphuric acid and mercury.  Four atoms
of acid are required to convert  the mercury into  this
salt.  The following diagram represents the theory of
its formation.
    1    rSul. ac. 32___.---------Sulphurous acid.
Sulphuric <
 acid 40 C Oxygen  8 -
    1    r Sul. ac. 32 -
Sulphuric <
 acid 40 (_ Oxygen  8
Sulphuric acid,     40
Sulphuric acid,     40
Mercury,          200
Sulphurous acid.
Bisul. Per. Mer.
            PLATINUM,  98,  (98-6.)

  This valuable metal appears to have been discovered
by Mr. Wood.  It is only found in the metallic state,
usually in small grains, associated with a number of
other metals.  It  is the heaviest substance known.
With oxygen it combines in two proportions:
                     Platinum.   Oxygen.
       Protoxide,         98  +   8 =  106.
       Deutoxide,         98  +  16 =  114.

  Palladium, Iridium, Rhodium, Osmium, Pluranium,
and Rhutenium, are metallic bodies, all contained in the 
67
 ores of platinum, but  they have hitherto been obtained
 in very small quantities, and the properties of most of
 them are but little  known.

  COBALTUM, OR COBALT, 29, (29-5,) AND
     NICKELUM, OR NICKEL, 29, (29-5.)

  These two metals are almost always found in meteoric
 iron, and the ores which yield one are commonly found
 to contain the other.   Both of them, like iron, may be
 rendered permanently  magnetic.   They  are both sus-
 ceptible of two degrees of oxidation; the oxygen in the
 two oxides being as 1  to 1.5.  Cobalt is a brittle metal,
 but nickel is both malleable and ductile.

         ZINCUM, OR ZINC,  32,  (32-5.)

  This element  seems to have been first described  by
Agricola.  The zinc of commerce is obtained from the
native sulphuret and the carbonate. It unites to oxygen
in but one proportion, which is constituted of one atom
of the metal  and one of oxygen.
  Sulphuret  of Zinc.—This is found abundantly  in na-
ture, and is composed of one atom of each of its con-
stituents; it is called blende.
  Carbonate  of Zinc.—This is the calamine of mineralo-
gists, and it  is made artificially by adding carbonate of
potash to sulphate  of zinc.

„  ,    ,  r Carb.  acid 22----------7Carb.  zinc  63
Carbonate)
of Potash £ Potash     4g

„  . ,  ,  C Oxide zinc 40
Sulphate )
\z
of Zinc^ Sulph>aci(i 40-------_N Sul> potasb m 
68
  Sulphate of Zinc.—This is often called white vitriol.
It is made for commercial purposes by roasting the na-
tive sulphuret in a furnace, so as to bring its elements
to a maximum of oxidation.
  Sulphate of zinc, or white vitriol, when administered
in the dose of a  scruple, is the most immediate emetic
we possess.  It is very frequently employed in the treat-
ment of poisoning, and its presence therefore may some-
times  interfere  with various medico  legal analyses.
The mode of detecting the salts of zinc is to add the
carbonate of ammonia  to a solution of the pure salt;
the white carbonate of zinc is thrown  down, which is
dissolved in an excess of carbonate of ammonia, and is
not again precipitated by boiling.  A stream of sulphu-
retted hydrogen  also opcasions a tohite precipitate;  the
sulphuret of zinc, which is very characteristic.  When
the  sulphate of  zinc has been mixed with animal and
vegetable substances the action of the tests is somewhat
modified: in such circumstances  Dr.  Christison advises
to strain the mixture through gauze, then  to acidulate
with acetic  acid, and  afterwards filter the solution.
The  acetic acid  dissolves any oxide of zinc that may
have been thrown down in union with the animal matter.
Through this  cool,  concentrated, filtered  and  neutral
solution  sulphuretted hydrogen is  to be  passed;  the
white  or grayish precipitate thus  produced is to be
washed  and dried, and heated  to  redness in a  tube.
When  cooled, strong nitric acid is  added, which dis-
solves the zinc and leaves the sulphur.   The carbonate
of ammonia, when added to this  nitric solution diluted,
will then precipitate the white carbonate.  The action
of heat on this carbonate ought to be particularly relied
upon. 
69
  Cadmium is a rare metal, discovered by Stromeyer, in
the oxide of zinc.

    "  BISMUTHUM, OR BISMUTH, 71.
  This metal has been long known; it is mentioned by
Paracelsus.  It is found native, and the metal of com-
merce is derived from the ore by simple fusion, in order
to separate the stony matter to which it is usually at-
tached.   Next to tin it is the most fusible of the solid
metals.   With oxygen it unites in but one proportion;
one atom of each of the elements compose the  oxide.
  Nitrate of Bismuth, thrown into water, deposits a
beautifully white powder called magistry of bismuth,
which is used as a cosmetic.

        ARGENTUM, OR SILVER, 108.
  Silver was perhaps the first metal known.  It has
been found native in a state of purity in immense masses.
With oxygen  it unites in but one proportion, which
compound is formed by  one atom of each element.
  Sulphuret of Silver, one of the ores, is composed of one
of silver and one of sulphur.
  Nitrate of Silver is the most important salt of  this
metal.  It is prepared by digesting silver in nitric acid;
a portion of the acid yields oxygen to the  silver, and
the  oxide thus formed unites  to some undecomposed
nitric acid.   The diagram illustrates this change:
               f" 1 Deutoxide of Nitrogen 30.
  1 Nitric acid<
               C 3 Oxygen 24 } 348  ■)    510
                             V-Oxide  Nitrate of
       3 Silver,  -     -  324 J Silver > Silver or
                                         Lunar
       3 Nitric acid,     -     -    162J   Caustic 
70
    CERIUM, GLUCINUM, YTTRIUM AND
                  THORINUM.

  These metals have only been found in small quantity,
and their properties have not been fully investigated.

            ALUMINUM,  13,  (13-7.)

  This metal was discovered by  Sir H. Davy.  It is
the base of alumina, which is  one of the most abundant
productions of nature.   It forms not only the principal
ingredient in all plastic clays, but some of the most
beautiful gems are  composed  of nearly pure alumina;
the ruby and the sapphire are examples of this kind.
Alumina is the sesqui-oxide  of aluminum, and is  the
only compound of its constituents known; 25  is  its
atomic weight or combining proportion.
  Sulphate of Alumina and Potassa.—This double salt
is the alum of commerce: it is composed of
    Sesqui-sulphate of Alumina,   -    2 atoms
    Sulphate of Potash, -     -    -    1 atom
    Water,.....24 atoms 
PART  II.
CHLORINE  AND ITS COMBINATIONS WITH
          ELEMENTARY  BODIES.
  Chlorine gas was discovered by Seheele.  It is ob-
tained by the action of muriatic acid on the black oxide
of manganese.  The following sketch will exhibit the
theory of its formation:
   2   r Chlorine  36
Muriatic < Mur. acid 37
Acid 74 C. Hydrogen  1

1  Black r Prot. Man. 36
Oxide of<
Man. 44 C Oxygen    8
    36
Mur. Prot. Man. 74
Water 9
  Chlorine is also procured by adding sulphuric acid
to a mixture of chloride of sodium, (common salt,) and
the black oxide of manganese.  The chemical changes
may be represented as follows:
60 Chlor. C Chlorine
  Sodium t. Sodium
44 Perox. C Oxygen
 Mangan. t Prot- Man-36
40 Sulphuric acid     40
40 Sulphuric acid     10
-Chlorine 36
Sul. Soda 76
Sul. Prot. Man. 76 
72
  The water with which the sulphuric acid is always
combined is not taken into account in the above ration-
ale, and the chloride of sodium  is not supposed to be
in solution.  During the process as it occurs in the arts,
the muriate of soda, and not chloride of sodium, occurs
in the mixture.   The chemical changes as expressed in
the preceding diagram, will be a little altered, as in the
following; the oxygen of the manganese uniting to the
hydrogen of the muriatic acid.
           Chlorine   36    -    -    -     -    36
           Soda       32
69 Mur.
  of Soda
           Hydrogen   1
44 Perox. C Oxygen     8
   Mang. I Prot. Man. 36
40 Sulphuric acid,      40
40 Sulphuric acid,      40
-3^------Water,
Sulph. of Soda 72
Sul. Prot. Man. 76
  The following table exhibits  some of the most im-
portant compounds  of chlorine  with the non-metallic
substances previously described.
Protoxide of Chlorine,
Peroxide of Chlorine,
Chloric acid,
Perchloric acid,

Chloride of Nitrogen,

Muriatic acid,

Chloro-carbonic acid,

Chloride of Cyanogen,
By volume. Chlor. Oxyg. 36+8	By weight. Chlor. Oxyg. 2 1
36 + 32	2 4
36 + 40	2 5
36 + 56	2 7
Chlor. Nit. 144 + 14	Chlor. Nit. 4 1
Chlor. Hyd. 36 + 1	Chlor. Hyd. 1 1
Chi. Car. Ox. 37 + 14	. CM. Car. Ox. 1 1
Chlor. ' Cyan. 36 + -26	Chlor. Cyan. 1 1
 
73
CHLORINE AND  OXYGEN.
  Protoxide of Chlorine.—This  gas was discovered by
Sir H. Davy.  It is  made  by the action of muriatic
acid on the chlorate of potash, and its formation arises
from the  fact that the muriatic and the chloric  acids
mutually  decompose each other.  Three atoms of mu-
riatic acid and one atom of  the chlorate of potash  are
used; one atom of muriatic acid unites to the potash of
the salt,  and thus liberates an atom of chloric  acid,
which instantly reacts on two atoms of muriatic acid,
and forms two atoms of water  and three atoms of  the
protoxide  of  chlorine.  The following diagram will
make these changes more evident:
   2    C2 Hydrogen 2
Muriatic < Chlorine 36
   74   C Chlorine 36
         ("Chlorine 36
   1      2 Oxygen  16
Chlorate J Oxygen
 Potash  | Oxygen
   124     Oxygen
         ^Potash
1 Muriatic acid,
2 Water 18.
3 Pro. Chi. 132.
Muriate of Potash 85.
  Peroxide of Chlorine.—This compound was discovered
by Sir H. Davy and Count Stadion.  It is formed by
the action of sulphuric acid on the chlorate of potash.
The  chemical  changes which  take place may be ex-
plained  by the following diagram.   Three atoms  of
chlorate of potassa and two of sulphuric acid are em-
ployed: 
74
fChlorine  36^
 Chlorine  36 U perox Chlorine 136.
 4 Oxygen 32 j
     2
Chlorate of
  Potash "S 4 Oxygen 32
   248    1 2 Oxygen 16
oe , i.  •  L2.?otash ?Sl-\----Sulph. Potassa.
2 Sulphuric acid,      80/   \        r
1 Chlorate of Potash, 124-------^Perchlo. Potassa.
  The whole products of the above decomposition are,
therefore, two atoms of peroxide of chlorine, two atoms
of sulphate of potash, and one atom of the perchlorate
of potash.
  Chloric acid.—This acid was first observed by Mr.
Chenevix.   Gay Lussac first obtained it in a separate
state, by adding a weak solution of sulphuric acid to
the chlorate of baryta; the insoluble sulphate of baryta
subsides, and the chloric acid remains in solution.  It
is hardly  necessary to add  the  following diagram to
exhibit this change:
1 Chlorate of ("Chloric acid,                      76
  Baryta 145?  Baryta 69 1 gul hate of Baryta    109
Sulphuric acid,  -  - 40 3    r
  Chlorate  of Potash.—This interesting salt was dis-
covered by Bertholet.  It  is made by passing chlorine
through a  concentrated  solution of pure potash.  Six
atoms of chlorine, five atoms of water, and six atoms of
potash, are necessary for  its production, and the pro-
ducts after the operation are five atoms of the muriate
and one atom of the chlorate of potash; the muriate re-
mains in solution, and the chlorate crystallizes in four
or six sided scales.
  Rationale of  the above process.—Five atoms  of the
oxygen of the water unite to one atom of chlorine and 
75
form one atom of chloric acid; at the same moment that
five atoms of its hydrogen unite to five atoms of chlo-
rine, and form five atoms of muriatic acid.  Both acids
combine with the potash, producing one atom of chlo-
rate and five atoms of the muriate of potash.   The fol-
lowing table shows the proportions in which the chlo-
rine and the elements of water unite:
1 Hydrogen +  1  Chlorine = 1 Muriatic acid = 37.
1 Hydrogen +  1  Chlorine = 1 Muriatic acid = 37.
1 Hydrogen +  1  Chlorine = 1 Muriatic acid = 37.
1 Hydrogen +  1  Chlorine = 1 Muriatic acid = 37.
1 Hydrogen +  1  Chlorine = 1 Muriatic acid = 37.
5 Oxygen    +  1 Chlorine == 1 Chloric acid  = 76.
  Perchloric acid.—This acid was discovered by Count
Stadion.  It is made from  the perchlorate of potash by
the addition of dilute sulphuric acid, aided by heat.

         CHLORINE AND NITROGEN.
  Chloride of Nitrogen.—This compound was discovered
by Dulong.  It is made by inverting a tall wide-mouthed
jar of chlorine  gas in a strong solution of muriate  of
ammonia, which  salt is decomposed by the chlorine;
the hydrogen of the ammonia unites  to one portion  of
the chlorine and forms muriatic acid, while the nitrogen
combines with another portion and generates the chlo-
ride of nitrogen.  The  diagram will illustrate the che-
mical changes during this  process.
     1      r Muriatic acid.
Muriate of< 3 Hydrogen-------^3 Muriatic acid.
 AmmoniaC. 1 Nitrogen  ^
Chlorine 14 Chlorine -       -1 Chlor. Nitrogen.
     g2 
76
         CHLORINE AND  HYDROGEN.

   Muriatic acid.—This acid, in its gaseous state, ap-
 pears to have been first noticed by Dr. Priestley.  It is
 made by adding sulphuric  acid to the  chloride of so-
 dium;  one atom of water in the acid is resolved into its
 elements, the hydrogen unites to the chlorine and forms
 muriatic acid, while the oxygen goes to the sodium
 and generates soda, which combines with the sulphuric
 acid and forms sulphate of soda.  The water contained
 in the liquid sulphuric acid is therefore  essential to the
 process. The following diagram exhibits these changes:

  Liquid C Hydrogen  1-----------^Mur. acid 37.
 Sulphuric < Oxygen  8")        ^^
  acid 49 C Dry ac- 40 3    ><^
 Chloride  C Chlorine  36 •"  ^^
 Sodi.  60 I Sodium   24----------^ Sulph. Soda72.

  When chloride of sodium is  dissolved in water it
 becomes the muriate of soda, the hydrogen uniting to
 the chlorine  forming muriatic acid, and the oxygen
 combining with the sodium to form soda; muriate of
 soda is therefore  always generated when chloride of
 sodium is in solution.  When sulphuric acid is added
 to a solution of chloride of sodium to form  muriatic acid
 the changes produced may be expressed as follows:
  Muriate of Soda C Muriatic acid = 37.
  Sulphuric acid 40 &°da } SulPhate of Soda = 72.

  Chloro-carbonic acid.—This compound was discovered
by Dr.  John Davy.  It is formed by exposing a mixture
of equal measures of dry chlorine and carbonic oxide to 
77
sunshine; rapid but  silent  union takes place, and they
contract to half their volume.  This acid unites to four
times its volume of ammoniacal gas, forming a white
solid, the chloro-carbonate of ammonia. Water decom-
poses chloro-carbonic acid, producing carbonic and mu-
riatic acids.   The annexed diagram will illustrate this
change:
1 Chloro- r Chlorine 36 -       -^Muriatic acid.
 carbonic < Carbon  6
 acid 50 C. Oxygen 8
Water  9 £ Hydrogen 1
water  y£Qxygen   8_________—^Carbonic acid.

  Chloride of Cyanogen.—This compound was first no-
ticed by Bertholet.  It is made by exposing the bicy-
anide of mercury, moistened with water, to the action
of chlorine; bichloride of mercury and chloride of cy-
anogen are the products.   The following sketch illus-
trates the theory and the composition of the products:

1 Bicyan. C 2 Cyan. 52 _      -^.2 Chi. Cy. 124.
 of Merc. <
   252   (Merc.  200
           2 Chlor. 72-

           2 Chlor. 72 —        -^ Bichl. Mer. 272.

           METALLIC CHLORIDES.

  Chlorine has a strong affinity for metallic substances,
and they may in most cases be made to unite directly
together.  All the  chlorides, except the proto-chloride
of mercury, or  calomel, and the chloride of silver, are
soluble in water; and as most  chemists imagine, these
       g3 
78
\
become muriates, the hydrogen combining with  the
chlorine and the oxygen with the metal.  The metallic
chlorides are again  produced from these solutions by
the application of heat, the hydrogen  and the oxygen
again uniting so as to form water, which escapes.

         CHLORIDES OF MERCURY.

  Chlorine combines with mercury in two proportions,
forming the protochloride, or calomel, and the bichlo-
ride, or corrosive sublimate.  These  compounds  are
analogous in their composition to the oxides of mercury;
their elements are united in the following ratio:
                   Mercury.            Chlorine.
  Protochloride,     200  or one atom + 36 = 236
  Bichloride,        200     „     + 72 = 272

  Bichloride of Mercury.—This compound is prepared
for medical purposes by subliming a mixture of the
bisulphate of the peroxide of mercury and common salt,
or the chloride of sodium.  The  diagram exhibits the
nature  of the action which takes place:

1 Bisulph.rMerc.   200 ---
Per.Merc.32Sul.ac.80]
    296   C 2 Oxyg. 16/\

2 Chloride r 2 Chlor. 72
 of Sodium-^
    120    C 2 Sodium 48---

   In this process the bichloride condenses  on the top
of the  subliming vessel  in a crystalline cake, and sul-
phate of soda remains at the bottom.  The presence of
mercury in fluids supposed to contain corrosive subli-
Bich.Mer.272.
Sul. Soda 144. 
79
 mate may be detected by digesting them  with pure
 potash.  The deutoxide of mercury which subsides  is
 to be separated, dried, and sublimed in a glass  tube,
 when metallic globules will appear lining the cavity of
 the tube.
   Rationale.—The  bichloride,  on being dissolved,  is
 changed to the bimuriate  of  the peroxide of mercury;
 the potash combines with the muriatic acid, and the
 peroxide of mercury precipitates;  heat then expels the
 oxygen, and the metal remains.
   The hydriodate of potash precipitates mercury from
 corrosive  sublimate, as a rich red duto-iodide.   The
 solutions, however, must be pure.  The theory may be
 illustrated as follows:
    2    r 2 Iodine  -------—,\ Deuto-iodide Merc.
 Hydriod.< 2 Hydrog.j       /
  Potash C 2 Potash I \/

 1 Corros. C 1 Mercury        n^
 Sublim. ^2 Chlorine---------2 Muriate of Potash.
  When the poison is mixed with organic substances,
then the solution, without previous filtration, is to be
agitated with about one-fourth  of its volume of ether,
which separates the poison from the aqueous part and
rises to the surface. This etherial solution  is then to
be evaporated on a watch glass, the residue dissolved
in hot water, and then, on adding to this a hot solution
of the  proto-muriate of tin, metallic mercury will be
precipitated.   The action  of proto-muriate of tin on the
bichloride of mercury, so as to produce the metal, may
be thus explained.  When the  first portions are added
a white powder is thrown down, which is calomel,
one atom  of chlorine leaving the  corrosive  sublimate
       g4 
80
and  uniting to the proto-chloride  of tin, converting it
into  the deuto-chloride, thus:

  Proto-chloride of  C Chlorine ^
        Tin         c Tin     > Deuto-chloride of tin.
                    f" Chlorine J
Corrosive Sublimated Chlorine") oaiomei
                    C Mercury 3
  As the tin has a stronger affinity for the chlorine than
the mercury, this change continues until all the chlorine
leaves the calomel and metallic mercury is revived. If
we consider  the tin in the above  experiment as the
muriate of the protoxide, and the  corrosive sublimate
as the muriate of  the  deutoxide of mercury, then the
proto-muriate  of tin,  from its powerful deoxidizing
agency, abstracts the oxygen from the peroxide of mer-
cury, and thus revives the metal.
  The proto-muriate of tin used in the process above, is
readily made by pouring strong muriatic acid on tin
foil;  heat is applied, and the solution must be kept from
the air.   In this experiment water  is decomposed, its
hydrogen escapes, perhaps as stanuretted hydrogen,
and the  oxygen unites  to the tin.
   2    ("Tin      58-----------7Stan. Hydrog. 59.
Tin foil <
  116  CTin      58 N
        C Hydrogen 1
Water 9-^
        C Oxygen   8 —        ^ Protoxide ~) Proto-
                                  of Tin 66 C Mur.
Muriatic acid,.....37 J Tin.
  Sulphuretted hydrogen is  an exceedingly  delicate
test for corrosive sublimate. The black deuto-sulphuret 
81
of mercury is formed by its action on the poison in  the
following manner:
   2    C 2 Hydrog. 2-------    — Mur. acid = 74.
 Sulph
Hydrog
  r2H
?-C2 S
Sulph. 32
Corros. f"2 Chlor. 72
 Subli- ]
 mate  C Mercury 200
Bisul.Mer.232.
i. Bisulph. of Mercury.
  If the poison in solution is considered as a muriate of
an oxide, then the rationale is as follows:

Sulphu- T2 Hydrogen—    —yWater.
 retted <.
Hydrog. C. 2 Sulphur

         ("2 Oxygen
 Bimur.  j
 Perox. X Mercury
Mercury | Muriatic acid.
         LMuriatic acid.

   Corrosive sublimate in solution may also be detected
by placing a drop of the suspected liquid on  a gilt but-
ton, and then touching it with a penknife or any piece
of iron; a white spot or an amalgam of gold will instantly
appear at the place where the iron and the gilding were
in contact.
   Corrosive sublimate is  converted  into calomel  by
many  animal and vegetable solutions,  muriatic acid
being liberated at the same time; albumen produces this
change instantly; the white of eggs is therefore a certain
antidote to this poison, if immediately administered.
   Proto-chloride of mercury, or calomel.—This important
preparation is commonly made by subliming a mixture
       g 5 
                        82

 of one atom or equivalent  of corrosive sublimate and
 one  atom of fluid mercury 'which has been previously
 triturated till the  metallic globules entirely disappear.
 A diagram will show clearly the nature of the change:
 1 Bichlor. r Mercury 200------------.Calomel 236.
 of Merc. < Chlorine  36—---'   "
   272   C Chlorine  36-^__^
 1 Mercury,  -  -  -200—      ---Calomel 236.
  When first prepared, it always contains a little cor-
rosive sublimate;  it should therefore be pulverized and
well washed before it is employed.  Calomel may also
be prepared by mixing muriatic acid, or any soluble
muriate, with a solution of the nitrate of the protoxide
of mercury.  The following diagram exhibits the action
of chloride of sodium on nitrate of mercury.
1 Chloride C Sodium  24-------^Nitrate Soda,  86.
Sodium 60 £ Chlorine 36.
 1 Nitrate rNit.  acid 541/
 Mercury < Oxygen   8y
   262    CMero.  200-------^Calomel,     236.

           MURIATE OF AMMONIA.

  This valuable salt, the  oldest  of all the ammoniacal
salts, is most commonly prepared by decomposing the
sulphate  of ammonia  by the muriate of soda.   The
changes produced may  be represented as follows:
1 Sulph. f" Ammonia 17 —         —^ Mur. Am. 54.
 Ammo. <
  57   C Sul. acid 40
   1    rMur. acid 37-
Muriate <
Soda 69 C Soda     32—       ---^ Sul. Soda 72. 
PART  III.
IODINE AND  ITS COMBINATIONS WITH
         ELEMENTARY BODIES.
  Iodine was discovered by M. Courtois.  It is obtained
from the dark residual liquor left in the vessels after
the carbonate of soda crystallizes, from the v ashes of
sea weeds.  This liquor contains a considerable quan-
tity of hydriodic acid, united to potash or soda; by add-
ing sulphuric acid and peroxide of manganese, the iodine
is produced, which must be collected in cool receivers.
The following diagram will illustrate the theory of its
production:

 Hydrio- C Iodine
 date of < Hydrogen  1
  Soda   C Soda      32
Peroxide C Oxygen    8
Mang. 44 I Prot. Man. 36
Sulphuric acid        40
Sulphuric acid        40
Water
126
  9
Sul. Soda    72
Sul. Prot. Man. 76
  The following table presents a view of the consti-
tution of some of the compounds of iodine. 
84
                    Iodine.              Oxygen.
Iodic acid,           126 or one atom    +  40 = 166
                    Iodine.              Nitrogen.
Iodide of Nitrogen,    378 or three atoms +  14 = 392
                    Iodine.              Hydrogen.
Hydriodic acid,       126        +         1 = 127
  Iodic acid was discovered by Davy and Gay Lussac.
It is made by decomposing a solution of iodate of soda
with sulphuric acid.
  Iodide of Nitrogen.—This compound is easily made
by triturating iodine in a strong solution of ammonia;
the alkali is decomposed, its elements unite to different
portions  of iodine, and form hydriodic  acid and iodide
of nitrogen.   The diagram will illustrate the change:

          r 3 Hydr.------------p3 Hydriodic acid.
Ammonia^ j Nitro_

          '3 Iodine'

           3 Iodine----------—1 Iodide of Nitrog.
  Hydriodic acid.—This acid gas is made  by adding
phosphorus to moistened iodine; mutual decomposition
ensues, the oxygen  of the water unites to the phospho-
rus and the hydrogen with the iodine.   The  diagram
will exhibit the theory of the changes:
  6
Iodine
Hydroge^}2Hydriodicacid'
2 Iodine,
  2   T2
Water ^ Oxygen     8 "^
      18   C Oxygen    8 >Phosphoric acid.
    Phosphorus        12 j
  Hydriodate of Potassa.—This salt exists only in so-
lution; it becomes the iodide of potassium  in the act of 
85
crystallizing.  It is made by adding a hot solution of
pure potassa to as much iodine as it will dissolve; the
iodate and the hydriodate of potassa will thus be quickly
generated.   The  rationale of this process is the  same
as that given for generating the chlorate of potash; sub-
stituting iodine  for chlorine.   The  mixed  iodate and
hydriodate of potash are then dried and exposed to a
low red heat in a platinum crucible; this converts the
whole mass into the iodide of potassium; the oxygen
both of the iodic  acid and of the potassa escaping in
the same manner as when the chlorate of  potassa is
subjected to a high temperature. 
PART  IV.
         BROMINE AND FLUORINE,

  Bromine was discovered by M. Balard.   It exists in
sea water, in the form of the hydro-bromate of magnesia.
It is prepared by passing a current of chlorine through
bittern, or the uncrystallizable residue left after common
salt has been  removed from it.   The chlorine decom-
poses the hydrobromic acid, uniting with the hydrogen
and thus liberating the bromine.  This change may be
illustrated as  follows:

u a  u    .. CBromine  78.26.
Hydro-bromate > tt j       . ^
 of Magnesia ) Hvdrogen  O
              C Magnesia 28 J> Muriate of Magnesia.
Chlorine     -    -    -  36 J

  The bromine is separated from the solution by means
of heat,  or by the addition of sulphuric ether.
  Bromine is so analogous to chlorine and iodine in its
chemical relations and agencies, that we shall merely
add the  following table, showing some of its  combina-
tions: 
87
                    Bromine.           Oxygen.
Bromic acid,           78 or one atom  +  40 = 118
                    Bromine.           Hydrogen.
Hydro-bromic acid,     78 or one atom  +   1 =  79
                    Bromine.           Chlorine.
Bromide of Chlorine,   78 or one atom  +  36 = 114
                    Bromine.            Iodine.
Bromide of Iodine,      78 or one atom  + 126 = 204

                   FLUORINE.

  Fluorine has never been obtained in a  separate state.
When the mineral called fluor spar  is  acted upon by
strong sulphuric acid, the compound called fluoric acid
is produced.  This was discovered by Seheele.   Some
chemists imagine that this acid is a compound of a cer-
tain inflammable principle called fluorine and oxygen,
and that the fluor spar from which it is produced is the
fluate of lime. On this view of its constitution the fol-
lowing is the rationale of its production:

Fluate C Fluoric  ac.-------—^ Hydrat. Fluoric acid.
of lime \ Lime      -^ ^—^^
Sulph. C Water    -" ~-\^
  acid  \_ Sulph. acid---------— Sulphate of Lime.

  A different and, perhaps, a more correct view is taken
of this subject. According to this theory, fluor spar is a
compound of fluorine and calcium, and the fluoric acid
is produced by the union of hydrogen  with fluorine.
When sulphuric acid is poured upon the fluate of lime,
the following is the theory of the changes which occur: 
Fluor spar,f"Fluorine  -         _,Hydro-fluor. acid.
or Fluoride <
of Calcium C Calcium
          C Hydrogen y
Sulph. acid^Oxyg^ |-------^ Sulphate of Lime.

  The chemical changes are the same as when sulphu-
ric acid is added to chloride of sodium. 
INDEX.
 Acid, Antimonic,       51
    Antimonious,       50
    Arsenic,       41, 42
    Arsenious,         41
    Auric,             57
    Carbonic,          19
    Chloric,            72
    Chloro-carbonic,    76
    Croconic,          22
    Fluoric,            87
    Formic,            27
    Hydriodic,         84
    Hydro-chloric,      72
    Hydro-ferrocyanic,  62
    Hydro-fluoric,      88
    Hypo-carbonic,     21
    Hypo-nitrous,       10
    Hypo-phosphorous,  31
    Hypo-sulphuric,    37
    Hypo-sulphurous,   37
    Iodic,              84
    Nitric,             12
    Nitrous,            11
    Oxalic,            21
    Phosphoric,        30
    Phosphorous,       31
    Prussic,            25
    Pyro-phosphoric,    30
    Sulphuric,         34
    Sulphurous,        36
Alumina,               70
Ammonia,               15
Antimony,             49
    Oxides of,          50
    Sulphurets of,       51
Antimony,
Phosphate of,	53
Tartrized,	53
Arsenic,	41
Sulphuret of,	43
Tests for,	41,42
Blue, Prussian,	62
Bromine,	86
Bromates,	86
Calamine,	67
Calcium,	48
Calomel,	81
Carbon,	17
Carburetted Hydrogen,	
	27,29
Caustic, lunar,	69
Chlorates,	74
Chlorine,	71
and Cyanogen,	72
and Hydrogen,	72
and Nitrogen,	72
and Oxygen,	72
Chromium,	55
Copper,	63
Carbonate,	63
Oxides of,	63
Sulphurets of,	62
Sulphate of,	64
Tests for,	64
Cyanogen,	22
and Oxygen,	23
and Hydrogen,	25
Emetic, Tartar,	53
Fire damp,	29
Fluorine,	87
 
90
Gold,	57	Nickel,(	67
Oxides of,	57	Oxides of,	67
Nituret of,	58	Nitre,	44
Hydrogen,	13	Nitrogen,	7
Oxides of,	14,15	Oxides of,	8
Arsenuretted,	42	With Hydrogen	15
Carburetted,	27	Olefiant gas,	27
Phosphuretted,	32	Oxygen,	5
Sulphuretted,	38	Phosphorus,	29
Iodide of Nitrogen,	84	With Hydrogen	32
Iodine,	83	With Iodine,	84
and Hydrogen,	84	With Oxygen,	30
and Oxygen,	84	Platinum,	66
Iron,	60	Oxides of,	66
Carbonate of,	61	Potash,	44
Oxides of,	60	Carbonate of,	45
Sulphate of,	61	Chromate of,	55
Iron ana Cyanogen,	62	Nitrate of,	44
Lead,	58	Sulphate of,	45
Carbonate of,	59	Sulphuret of,	45
Chromate of,	59	Prussian blue,	62
Oxides of,	58;	Silver,	69
Iodide of,	59	Nitrate of,	69
Phosphate of, Sulphate of,	59	Oxide of,	69
	59	Sulphuret of,	69
Tests for,	59	Soda,	46
Lime,	48	Carbonate of,	46
Carbonate of,	48	Phosphate of,	46
Nitrate of,	48	Sulphate of,	47
Phosphate,	48	Sulphur,	33
Sulphate,	49	With Hydrogen,	38,40
Lunar caustic,	69	With Oxygen, 34,36,37	
Magnesia,	49	Tin,	43
Manganese,	58	Oxides of,	43
Oxides of,	58	Urea,	25
Mercury,	64	Water,	14
Oxides of,	64	Zinc,	67
Chlorides of,	78	Carbonate of,	u.
Cyanide,	65	Oxide of,	67
Iodides,	79	Sulphate of,	68
Sulphate of,	66	Sulphuret of,	67
 
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