CHEMISTRY. 
341 
oxygenated in the first degree. It is there- 
fore called arsenious acid. It possesses a 
weak acid taste ; it sensibly reddens tbe tinc- 
ture of litmus. If placed on burning coals, 
or on a red-hot iron, it is volatilized in the 
form of a white vapour, which has a strong 
smell resembling garlic. It is in a small 
degree soluble in water. The white arsenic 
of tire shops is chiefly obtained from arsenical 
ores of cobalt. These are thrown into a fur- 
nace resembling a baker’s oven, with a long 
flue, or chimney, into which the fumes pass, 
and are condensed into a greyish powder. 
This is refined by a. second sublimation in 
close vessels, with a little alkali. As the 
heat is considerable, it melts- the sublimed 
arsenic into opaque crystalline masses, which 
are known in commerce by the name ot 
white arsenic. 
Of arsenic acid . — Arsenic acid is produced 
only bv art. It appears in the form ol a 
white pulverulent matter. All the prepa- 
rations of arsenic are deadly poison ; the 
hydro-sulphurets are the best antidotes. A 
weak solution of hydro-sulphuret of potash, 
soda, or lime, is therefore often administered 
with sue ess, if given in time, to persons who 
have been poisoned by arsenic. Sulphureous 
mineral waters may also be given. In such 
cases oil, milk, butter, &c. which are too 
often resorted to, should never be employed, 
if a sulphuret, or hydro-sulphuret, can possi- 
bly be procured. 
Of tungstic acid . — This acid does not 
exist in an uncombined state in nature. It 
is procured from a mineral called tungsten, 
which is a combination of this acid with 
lime (tungstate of Lime), or from wolfram, 
which is this acid united to iron and manga- 
nese; It appears in a pulverulent form, 
harsh to tire touch. It is tasteless, and in- 
soluble in water. It is not capable of turn- 
ing blue vegetable colours red, until it has 
been first rendered soluble by ammonia. It 
is of a yellow colour, which becomes blue on 
being exposed to the light. 
Of rnoh/bdic acid.— We are indebted to 
Mr. Hatchett for a thorough knowledge of 
the properties of this acid, and of all its com- 
binations. It is molybdena oxygenated ; for 
this metal is susceptible of oxygenation to 
such a degree as to become a concrete acid. 
It is soluble in about 570 parts of water. 
The solution reddens tincture ot litmus. 
It is not applied to an\ use. 
Of chromic acid .— This acid is very little 
known. In nature it is found combined with 
oxvd of lead, in the mineral called chromate 
of 'lead, or the red-lead of Siberia; also 
united to iron, alumina, and silex, in the sub- 
stance called chromate of iron. 
Of cohunbic acid . — r l his acid is as little 
known as the last. It is found in the newly 
discovered ore called columbium, or colum- 
bat of iron. 
Of acetous acid. —This acid exists, mixed 
with other substances, in common vinegar. 
Since, this acid is very volatile, it is obtained 
pure by distilling vinegar in a sand-heat. It 
is also called distilled vinegar, and is perfectly 
colourless, and of a pleasant sour taste and 
odour. Its base is carbon and hydrogen ; the 
addition of oxygen forms acetous acid. 1 he 
same principles form the bases of the other 
vegetable acids, but in different proportions. 
’The acetites of potash and soda, are ob- 
tained by neutralizing the carbonates of these 
alkalis with acetous acid, and evaporating and 
crystallizing lire solution. . It was formerly 
supposed, that when deprived of -part of its 
carbon, it formed another state or the acid, i 
which was called acetic acid : but il has been | 
shewn by (Iren, that there exists but onefistate 
of the acid, and what was called acetic acid 
differed only in the degree of concentration. 
Of malic acid. — ■'This acid is found in the 
juice of unripe apples, and other fruits, and 
is procured by saturating the juice ot apples 
with potash., and adding a solution ot acetite 
of lead till it no longer occasions a precipi- 
tate ; wash this precipitate, which is malate 
of lead ; pour over it sulphuric acid until the 
liquor acquires an acid taste without any mix- 
! tore of sweetness, and fibre the whole in 
j order to separate the malic acid from the 
j sulphate of lead which is formed. 
I Of oxalic acid. — Oxalic acid, formerly 
called the acid of sugar, is prepared from 
sugar by treating it with nitric acid. It has 
a stronger attraction for lime than any other 
acid. It is therefore employed to discover 
the presence of lime in any solution. It is 
always concrete. It forms with alkalis, earths, 
and metals, salts called oxalates. 
Of citric acid. — Citric acid is found in the 
juice of lemons and oranges, unripe grapes, 
and other sour fruits. It crystallizes, and 
when concrete is not changed by the air. It 
dissolves in water, and has a very pleasant 
acid taste. • It is used for a variety of pur- 
poses, and of late extensively in the art ot 
calico-printing. 
Of tartaric acid. — The tartar found ad- 
hering to casks in which wine has been fer- 
mented, is a salt composed of a peculiar acid 
combined with potash, but in such a manner, 
that the acid is in considerable excess. The 
salt is known under the name of acidulous 
tartrat of potash, and the acid which enters 
into its composition is the tartaric acid. 
This may be obtained by dissolving two 
pounds of crystals of tartar in water, and 
throwing in chalk by degrees, until the liquid 
is saturated. A precipitate forms, which is 
tartrite of lime. By adding nine ounces of 
sulphuric acid, and five ounces of water, to 
this tartrite, and digesting them together for 
twelve hours, the tartaric acid is set at li- 
berty, and mav be cleared from the sulphate 
of lime by means of cold water. The acidu- 
lous tartrat of potash, or cream of tartar, is 
formed from crude tartar, by solution, and 
subsequent filtration and evaporation. See 
Tartar. 
Of benzoic acid. — -This acid is obtained by 
sublimation from the resin called benzoin, 
and exists in the balsam of Peru and that of 
Tolu, and some other substances ot this kind. 
It is also found in urine, and many animal 
substances. See Benzoin. 
Of camphoric acid. — The camphoric acid 
is camphor oxygenated to acidity, by boiling it 
with nitric acid. This acid exists in the form 
of white crystals, which effloresce in the air. 
Its taste is acid and bitter. It reddens blue 
vegetables. See Camphor. 
Of gallic acid. — 'Phis acid is found in the 
gall-nuts, bark of trees, and in all those vege- 
tables called astringents. Its taste is sour 
and astringent. It reddens vegetable blues. 
It crystallizes. It has a strong tendency to 
unite with metallic oxyds. It forms with the 
several metals precipitates of different co- 
lours. With gold, it forms a brown precipi- j 
tate; with silver, grey ; mercury, an orange; 
copper, a brown ; lead, a white ; and iron, 
a black precipitate. The base ot ink is iron, 
thus precipitated; one pound of powdered 
nutgalls being infused for four hours, without 
boiling, in common water, with six ounces 
of gum-arabic, and six ounces of sulphate of 
iron, or green copperas, good black ink is 
produced. To obtain gallic acid, dissolve 
two ounces of common alum in water, and 
precipitate the solution by letting fall into 
it a solution of potash ; wash the precipitate 
well, and transfer it into a decoc ion of goll- 
nuls (obtained by infusing one ounce of 
gall-nuts in sixteen of water, and evaporating 
the liquor to one-half), agitate the mixture 
frequently during the course of 24 hours, 
and then nitre it. The fluid which passes 
through the liltre is gallic acid ; which may 
be obtained in the form ot needle-shaped 
crystals, by evaporating it slowly till a pel- 
licle appears, and then letting it stand undis- 
turbed. 
Of succinic acid. — This acid is obtained by 
distillation from amber, and is therefore 
called also acid of amber. It is very soluble 
in hot water, anti crystallizes by cooling. 
See Amber. 
Suberic acid. — This acid is obtained by 
the action of nitric acid on cork. It reddens 
vegetable blues, and has the peculiar pro- 
perty of turning the blue solution of indigo 
m sulphuric acid to green. 
Phosphorous acid. — When phosphorus is 
burnt slowly, and does not become com- 
pletely saturated with oxygen, it forms an 
acid, called phosphorous acid. It is liquid, 
transparent, and of considerable density. It 
has an unpleasant taste, and emits a disagree- 
able odour when rubbed, and especially 
when warmed. It is more volatile than phos- 
phoric acid. 
Of phosphoric acid. — Phosphorus satu- 
rated with oxygen, forms phosphoric acid, 
which is capable of existing in a dry state. 
It dissolves in water, and affords a transpa- 
rent fluid void of odour. When exposed to 
heat, it is rendered viscous, and by degrees 
becomes consistent, and loses its transpa- 
rency. When urged by a violent heat, it 
melts into a transparent glass, which again 
attracts moisture when expo ;ed to the air, 
and becomes converted into liquid phos- 
phoric acid. When melted in an earthen 
crucible, it acts upon the crucible, and fuses 
into a glass, which is not soluble in water, 
and exhibits no signs ot acidity. It has a 
strong attraction for all the alkalis and 
earths. T his acid is obtained from bones, , 
which are chiefly phosphate of lime. It may 
also be obtained by th • rapid combustion of 
phosphorus in oxygen. See Phosphorus. 
Sebucic acid, called the acid of fat, is ob- 
tained from the fat of animals. It is con- 
crete, and soluble in water. It is sour, and 
without odour. 
Laccic acid has been discovered by Dr. 
Pearson, in a substance called white lac, 
formed by certain insects of the coccus 
tribe. By exposing this substance to such a 
degree of heat as was just sufficient to liquefy 
it, a fluid was obtained, to which the doctor 
lias given the name ot laccic acid. 
Lactic acid is found in the whey of milk. 
It is concrete, and liquefies in the air. It is 
sour, and oxydates the metals. 
Succho-luctic acid, was discovered by 
