< 'itrie. Succinic, 
Tartaric, Suberic. 
Animal acids. 
Phosphorous, Lactic, 
Phosphoric, Saceho-lactic, 
Scbacic, Prussic. 
Laccic. 
Of sulphurous acid .— This is sulphur com- 
bined with oxygen, but not to saturation. It 
is the sulphurous acid gas when absorbed by 
water. The salts formed by the combination 
ot this acid with different bases, are called 
sulphites; they are not employed for any 
useful purpose ; they are converted into sul- 
phates by heat. 
Of sulphuric acid . — Sulphuric acid, for- 
merly called spirit or oil of vitriol, is formed 
by the combination of sulphur, which is its 
base, and oxygen. It is obtained when the 
combustion ot sulphur is carried on very 
slowly with access of atmospheric air; but it 
is produced with more facility by the addi- 
tion of saltpetre, now called nitrate of potash, 
which furnishes oxygen abundantly, and 
enables the- combustion to go on more ra- 
pidly. 
In operations of this kind, on a large scale, 
the mixture of sulphur and saltpetre is burnt 
in large chambers, the sides of which are 
cased with plates of lead, and water is placed 
on the Hour, to collect the sulphuric vapours. 
The water is afterwards put into large re- 
torts, and distilled by a moderate heat ; wa- 
ter slightly acid passes over, and concentrated 
sulphuric acid remains in the retort. This 
acid suffers congelation by intense cold ; it is 
unctuous to the touch, attracts moisture from 
the atmosphere with great avidity, and, when 
mixed with water, produces a heat above 
that of boiling water. It acts rapidly on all 
inflammable substances, rendering them black, 
the acid itself becoming brown, or even black- 
ish. It combines with nitrous acid, and 
forms a compound which dissolves silver, 
but scarcely any other metal. 
Sulphates are neutral salts, formed by the 
sulphuric acid with certain bases. Thus, 
sulphate of potash, formerly called vitriolated 
tartar, is produced by the combination of the 
sulphuric acid and potash. 
Sulphate of soda, formerly called Glauber’s 
salt, is formed by the combination of soda 
with the sulphuric acid. It is found fre- 
quently in mineral waters. See Sulphur. 
A il rous acid . — Nitrous acid exists in the 
state of gas, in the form of a red vapour ; it is 
nitrous gas combined with a limited quantity 
ot oxygen: it is rapidly absorbed by water, 
and, when combined with it, is of a yellow or 
orange colour. It emits copious orange-co- 
loured or red fumes. Different quantities 
of water convert its colour to a deep blue, 
green, yellow, &c. while the vapours still 
continue of their original yellowish-red co- 
lour. 
Liquid nitrous acid, generally called spirit 
of nitre in the shops, is only nitric acid (to 
be afterwards described), holding in solution 
a quantity of nitrous gas. If this nitrous acid 
is heated, the nitrous gas is disengaged, 
which coming into the air, attracts oxygen, 
and becomes nitrous acid gas, appearing in 
the form of red fumes, and {he liquid is con- 
verted into colourless nitric acid. 
The following is the process made use of 
■for procuring nitrous acid: Take a quantity 
CHEMISTRY. 
of sulphate of iron (martial vitriol), deprived 
of its water of crystallization by heat, and mix 
with it an equal weight of dry nitrate of pot- 
ash; put the mixture into a glass retort, to 
which a very spacious receiver has been luted, 
containing a little water, and begin to distil 
with a very slow tire. As soon as the red va- 
pours cease to come over, let the fire be 
slackened; arid when the vessels are cooled, 
the receivermust be cautiously withdrawn, and 
its contents quickly transferred through a glass 
funnel into a bottle furnished with a ground 
stopper. It may also be obtained by decom- 
posing nitrate of potash, by means of sulphu- 
ric acid, with the assistance of heat. 
The nitrites are very little known. 
Of nitric acid . — The constituent principles 
of this acid are oxygen and nitrogen (or azote). 
It differs from the last-mentioned acid, only in 
not having any nitrous gas in a loosely com- 
bined state. 'Oxygen and nitrogen with ca- 
loric, form nitrous gas, which, with a greater 
quantity of oxygen, forms nitric acid. 
Nitric acid is transparent, liquid, and co- 
lourless; when diluted with water, it Is sold 
m tiie shops by the name of aqua-fortis. It 
possesses in an eminent degree all the pro- 
perties of acids. It is capable of oxydating 
! all the metals, except gold and platiua. It 
j thickens and blackens oils, converting them 
to a coal, or inflaming them, according to 
the nature of the oil and the degree of con- 
centration of the acid. It is procured by re- 
distilling nitrous acid, or at least heating it 
till it is deprived of its fumes. The combi- 
nations of nitric acid with different bases, are 
called nitrates. 1 liese salts have the proper- 
ty of detonating with, or inflaming charcoal, 
and other easily inflammable bodies, at a red 
heat It is upon this property that the com- 
position of gunpowder is founded, which con- 
sists of five parts of nitrate of potash, one of 
charcoal, and one of sulphur. 
Nitrate of potash, nitre, or saltpetre, is 
formed by the combination of the nitric acid 
with potash. It is produced spontaneously 
m various situations, sometimes efflorescing 
on the surface of the earth, and on the walls 
of old buildings. It may be artificially pro- 
duced by the putrefaction of animal and ve- 
getable substances ; light earths, such as lime 
and marl, ashes, the refuse of soap-manufac- 
tures, &c. being stratified for this purpose 
with straw, dung, and putrifying animal and 
vegetable substances, and wetted with urine, 
blood, dunghill-water, and the mother-waters 
of saltpetre, turned, and exposed to a cur- 
rent of air. It is formed in these processes 
by the extrication of nitrogen, by the decom- 
position of the animal and vegetable sub- 
stances, which combines with the oxygen of 
the atmosphere, forming nitric acicl ; and 
this, uniting with the alkali, which is sepa- 
rated at the same time from these substances, 
forms the nitrate of potash. See Nitre. 
Nitrate of lime, formerly termed nitrous 
selenite, is found adhering to, and embodied 
in, calcareous stone, and dissolved in various 
mineral springs. It is formed near inhabited 
places, and is yielded by the lixiviation of old 
plaister, and by the mother-waters of salt- 
petre, as they are termed by the manufac- 
turers. It may be frequently observed as an 
efflorescence upon old damp walls. 
Of muriatic acid . — Muriatic acid, formerly 
termed marine acid, or acid of sea-salt, is 
supposed to consist of oxygen, in combing- 
UuT 
339 
tion with a peculiar but hitherto unknown 
basis ; for it has never yet been decomposed. 
It exists in the gaseous state, and forms mu- 
riatic acid gas, which has been considered 
already. This, absorbed by water, consti- 
tutes liquid muriatic acid. ' The muriatic 
acid is dill used in great abundance through- 
out the mineral "kingdom, and is united 
chiefly with soda, lime, and magnesia; it is 
found with these three bases in sea-water, 
and in that ot several lakes. In mines of 
rock-salt it is for the most part united with 
soda. 
Ihe muriatic acid does not adhere very 
strongly to the earths and alkalies. The 
sulphuric acid is capable of separating it from 
them ; and it is by means of this acid that 
chemists obtain the muriatic. 
Experiment. Put eight parts of purified 
muriate of soda, reduced to fine powder, 
into the retort A (fig. 23.), and five parts of 
sulphuric acid diluted with a small quantity 
ot water. Adapt to the retort the matrass C, 
to receive the portion of impure sulphuric 
and muriatic acid which passes over towards 
the end of the operation. I), E, and F, are 
a series of bottles in which water is put, the 
quantity of which is equal to the weight of 
the salt employed. These bottles arc fur- 
nished with safety-tubes, G G. T he joinings 
must be well luted, and the heat gradually 
increased^ till nothing more can be disen- 
gaged. The muriatic acid will pass over in 
the state of gas, and unite itself in a large 
proportion with the water in the receiver. 
} he water thus saturated is muriatic acid. It: 
is a colourless fluid. It emits copious white 
fumes in contact with moist atmospheric air, 
which is muriatic acid gas, that escapes from 
it, and condenses again, by combining with 
the humidity of the air. Its combinations with 
earths, alkalies, and metals, form muriates. 
Muriate of potash, the febrifuge salt of 
Sylvius, is formed by the combination of mu- 
riatic acid with potash. It is found in sea- 
water and old plaister.. It lias a strong bitter 
disagreeable taste. 
Muriate of soda, marine salt, common 
salt, is formed by the combination of muri- 
atic acid with socla. It is found native in 
" luies > ^ many places, but particularly in 
Roland and Hungary. It is also obtained by 
extracting it iron, sea-water by evaporation”, 
&c. It is always, contaminated by a quantity 
ot muriate of magnesia, muriate of lime, and 
sometimes by the sulphate of lime. It occa- 
sions clay to fuse readily, and is employed in 
glazing earthenware. It assists the fusion 
oi glass also. It lias a penetrating pleasant 
taste, decrepitates 011 hot coals, and by great 
heat is volatilized. 
Muriate of ammonia, or sal ammoniac, is 
formed by the combination of the muriatic 
acid with ammonia, and is found native in 
manv parts, particularly in the neighbour- 
hood ot volcanoes. It is obtained artificially 
by sublimation, from the soot formed by the 
combustion of the excrements of animals 
which feed on saline plants. 
Muriate of lime is found in mineral waters 
but particularly in the waters of the Sea , * 
which u contributes to give their bitter taste 
It speedily dehouesces. It fuses with a U)0 1 
derate heat, and by calcination becomes the 
phosphorus of Hombeig. tUc 
Muriate of barytes is not known to exist 
native. 1 he sulphuric and fluoric acid do 
