338 
'veil : st is also the solvent of glass. Alka- 
lies dissolve silex in the dry way, and with 
it form glass. Silex cannot be fused by a 
burning lens; but by exposing it to. a live, 
urged by oxygen gas, Lavoisier produced a 
commencement of fusion on its surface. See 
Silex. 
Strontian was discovered by Dr. Hope, 
professor of chemistry at Glasgow. It is 
found in the state of a carbonate, that is, 
combined with carbonic acid, in a vein 
of lead ore, at Strontian in Argyleshire, in 
the western part of Scotland. It has been 
found also combined with carbonic acid at 
Lead-hills, in the same country. Some of 
it has since been discovered at Montmartre 
in France, combined with sulphuric acid ; 
and it is found in quantities in the neighbour- 
hood of Bristol. 
' Strontian was at first confounded with ba- 
rytes ; which indeed it resembles in several re- 
spects, though it differs from it in others. 
Carbonate of strontian is decomposed by 
the sulphuric acid, and carbonic acid is dis- 
engaged : the sulphate of strontian, thus ob- 
tained, is very little soluble in water. It dis- 
solves with effervescence in the nitric and 
muriatic acids, and carbonic acid is disen- 
gaged. These nitrates and muriates of stron- 
tian are not deliquescent, and are decompos- 
ed by the sulphates of lime, potash, and 
others. It may be deprived of its acid by 
calcination ; its earth is then soluble in water, 
but in greater quantity in boiling than in cold 
water, for a part of it is precipitated by cooling. 
The carbonate of strontian is lighter than 
carbonate of barytes : the specific gravity of 
the latter is from 42. to 43.000, that of 'the 
carbonate of strontian is only from 36. lo 
37.000. Analysis lias proved, that 100 parts 
of the carbonate of strontian contain 62 parts 
of strontian, 30 parts of carbonic acid, and 
8 parts of water. See Strontian. 
Zirconia is a simple earth, lately discover- 
ed by Klaproth, in the jargon of Ceylon, of 
which it is a constituent part, and even the 
most abundant ; for it has been found by 
analysis, that 100 parts of the jargon of Cey- 
lon contain 64 parts and a half of zirconia, 
32 parts of silex, and two parts and a half of 
the oxide of iron. To obtain zirconia pure, 
it must be united to the muriatic acid, with 
which it forms a muriate of zirconia ; this 
muriate must be dissolved in a large quan- 
tity of water, and the zirconia must be pre- 
cipitated by potash : if it is carefully wash- 
ed, and then brought to a red heat in a cru- 
cible, it will be perfectly pure. Calcined 
zirconia has a white colour. It is rough to 
the touch like silex ; it has no taste, and is 
not soluble in water. Its specific gravity is 
at least 43.000 ; tlrat of distilled water being 
10 . 000 . 
When separated from its solutions by 
caustic alkalies, this earth retains a pretty 
large quantity of water, which gives it the 
semi-transparency of horn ; it has then the 
appearance of gum-arabic, both by its slight- 
ly yellow colour and its fracture and trans- 
parency. It is susceptible of uniting with 
carbonic acid. It unites also with the sul- 
phuric and nitrous acids : alkalies, and the 
first six primitive earths, separate it from the 
latter acid. It will not alone fuse by the 
blowpipe ; but it fuses with the borate of soda, 
and gives a transparent colourless glass. 
Yttria is also a newly discovered earth, 
CHEMISTRY. 
and will be described under the article 
Yttria. 
Glucina is a simple earth, lately disco- 
vered by Vauquelin, in the aigue-marine, 
called the occidental. It is a white gra- 
nulated earth, which effervesces with acids. 
In 100 parts of this aigue-marine there are 
14 of glucina. It is soluble in the carbonate 
ot ammonia, as well as in the sulphuric acid. 
In the latter case, the solution has at first a 
saccharine, and afterwards an astringent 
taste. Its chrystals are sweet, like the so- 
lution. It has some resemblance to alumi- 
na ; as it is soft to the touch, adheres to the 
tongue, is light, dissolves in potash, and is 
precipitated from its solution by ammonia. 
But it differs from alumina by its combina- 
tions with acids being exceedingly sweet, by 
giving no alum when mixed with sulphate of 
potash, by being entirely soluble in carbon- 
ate of ammonia, and by not being precipi- 
tated from its solutions by oxalate ot potash 
and tartrite of potash, as alumina is. 
It has been found by analysis, that 100 
parts of earth contain 68 ot silex, 15 of 
alumina, 14 of glucina, 2 of lime, and one of 
the oxide of iron. 
Of Acids . — According to the theory of La- 
voisier, all acids consist of a certain base, 
united to oxygen, which is considered as 
the cause of acidity. See Acid. We are 
already acquainted with the bases of the sul- 
phuric, nitric, phosphoric, and arsenic acids ; 
we know that hydrogen, carbon, and oxygen, 
form the bases' of the vegetable acids ; and 
that the same substances, in combination 
with nitrogen, constitute the animal acids, 
such as prussic, &c. But we are totally un- 
acquainted with the bases of the muriatic, 
boracie; and fluoric acids. Acids are either 
solid, liquid, or gaseous. They excite a 
peculiar sensation on the palate, called sour. 
They change most of the blue vegetable 
colours red. Most of them unite to water in 
all proportions ; and some have so strong an 
attraction for it, as to be incapable of appear- 
ing in the solid form. 
All the acids combine with the alkalies. 
These combinations have been termed neu- 
tral salts. See Acid and Alkali. These 
salts are easily formed by art ; and nature 
exhibits a great number, especially of those 
which are formed by acids of simple radicals. 
Neutral salts are distinguished by two 
names ; one expressing the acid, and the 
other the alkaline base^ The first of these 
names may have two variations of termina- 
tion, corresponding to two different states of 
the acid in the salt. The termination ate, 
is employed when the acid is one of those 
which are completely saturated with oxygen, 
and whose names end in ic ; thus the salts 
compounded with the nitric acid, are called 
nitrates. Words terminating in ite, serve 
to distinguish the presence of those weak 
acids which are not fully saturated with oxy- 
gen, and which, when alone, have names 
ending in ous ; thus, nitrites are salts com- 
pounded with nitrous acid. For the crystalli- 
zation of salts, see Crystallization. 
All metallic substances combine with at 
least some of the acids. But the alkalies and 
earths enter into the composition of neutral 
salts without any uniting medium ; whereas 
the metals do not combine with acids, un- 
less they have been first more or less oxy- 
genated: we may therefore say, that the 
metals themselves are not soluble in acids, 
but only the metallic oxyds. When a metal- 
lic substance is put into an add, the first 
requisite, in order that it may dissolve, is, 
that it become oxydated in it. 1’or this 
purpose, it must take up oxygen, either 
from the acid, or from the water with which 
the acid is diluted ; the oxygen then must 
have more affinity for the metal than it has 
either for the hydrogen or for the base of 
the acid ; and consequently a decomposition, 
either of the water or of the acids, must 
take place. 
On these observations the explanation of 
the principal phenomena of metallic solutions 
depend. In metallic solutions, an efferves- 
cence, or disengagement of gas, often takes 
place. The gas disengaged by nitric acid, 
is nitrous gas ; that disengaged by sulphuric 
acid, is sulphurous ackl gas, if it be this 
acid that has furnished the oxygen ; but it is 
hydrogen gas, if the oxygen lias been fur- 
nished by the water. Nitric acid and wa- 
ter being composed of substances which, 
taken separately, exist only in the state of 
gases, as soon as they are deprived of their 
oxygen, the other principle assumes the 
gaseous form. It is this rapid passage from 
the liquid to the gaseous state, that consti- 
• tutes effervescence, ihe case is the same 
with the sulphuric acid. 
In general, the metals do not take from 
these acids all their oxygen ; they do not 
reduce the one to azote, and the other to 
sulphur, but to nitrous gas and sulphurous 
acid. Metallic substances dissolve without 
effervescence, when they have been previ- 
ously oxidated ; for in that case, the metal 
no longer has a tendency to decompose 
either the acid or the water. There is there- 
fore no disengagement of gas, and conse- 
quently no effervescence. 
No metal dissolves with effervescence in. 
oxygenated muriatic acid. In this case, the 
metal takes from the acid its excess of oxy- 
gen ; and the result is a metallic oxyd, and 
simple muriatic acid. 'I 'here is no efferves- 
cence, because there is no disengagement of 
gas. 
Metals which have very little affinity for 
oxygen, and which have not the power to 
decompose either the acid or the water, are 
insoluble in acids, unless they have been first 
oxydated. For this reason, silver, mercury, 
and lead, are not soluble in muriatic acid, 
when exposed to it in their metallic state; 
but if previously oxydated, they are exceed- 
ingly soluble, and the solution takes place, 
without effervescence. 
The following is a table of the acids hitherto 
known: 
Mineral acids. 
Sulphurous, 
Oxygenated muriatic. 
Sulphuric, 
llyper-oxygenated muriatic. 
Nitrous, 
Carbonic, 
Nitric, 
Fluoric, 
Muriatic, 
Boracic, 
Mellitic. 
Metallic acids. 
Arsenious, 
Molybdic, 
Arsenic, 
Chromic, 
Tungstic, 
Columbia. 
Vegetable acids. 
Acetic, 
Benzoic, 
M alic. 
Camphoric, 
Oxalic, 
Gallic, 
