Ores of mercury. We have very few ex- 
act analyses of the ores of mercury, owing, 
perhaps to the facility with which the mer- 
cury is extracted from them by distillation.' 
Native mercury and amalgam may be dis- 
solved in nitric acid. The gold, if any is 
present, remains in the state of powder, and 
maybe estimated by its weight. The affu- 
sion of water precipitates the bismuth, if the 
solution happens to contain any. Common 
salt precipitates the silver, and also part of 
the mercury; but the latter may be redissolv- 
ed by a sufficient quantity of water, or, 
which is far better, of oxy muriatic acid, 
while the muriat of silver remains insoluble. 
Lastly, the mercury may be precipitated by 
sulphat of iron, and estimated. 
2. Native cinnabar may be treated with a 
mixture of three parts muriatic and one part 
nitric acid, which dissolves the mercury, and 
leaves the sulphur. The mercury may be 
estimated as in the last paragraph. 
3. Hepatic mercurial ore has not been 
analysed. Its analysis may be attempted as 
in No. 2. or by dissolving it in nitric acid. 
4. Muriat of mercury may be digested in 
muriatic acid till the whole is dissolved. 
Muriat of barytes precipitates the sulphuric 
acid, 100 parts of which are equivalent to' 
186 of sulphat of mercury; and the propor- 
tion of this salt being known, we have that 
of the muriat. 
Ores of copper. Native copper sometimes 
contains gold, silver, or iron. It may be dis- 
solved in nitric acid; the gold remains in the 
state of a blackish or rather violet-coloured 
powder; the silver may be separated by a 
polished plate of copper (or it may be preci- 
pitated from a separate portion of the solu- 
tion by common salt); the iron may be sepa- 
rated by boiling the solution to dryness, and 
treating the residuum with water. By this 
process, the nitrat of iron is decomposed ; the 
oxide of iron remains, while the water dis- 
solves the nitrat of copper. This last salt 
may be decomposed by boiling it with potass; 
the precipitate dried in a red heat, is black 
oxide of copper. One hundred parts of it 
denote 80 of metallic copper. 
2. Sulphuret of copper may be dissolved 
in diluted nitric acid. Part of the sulphur 
remains unaltered, and may be estimated by 
weighing it, and burning it off. Part is aci- 
dified, and may be precipitated by nitrat of 
barytes; 100 parts of the dried precipitate 
indicating 1 4.5 of sulphur. Bv evaporation 
to dryness, and solution in water, the iron is 
separated ; and the copper may be estimated 
as in the last , paragraph ; or muriatic acid 
may be used instead of nitric; but in that 
case it is more difficult to obtain a complete 
solution. 
3. Grey copper ore was analysed by Kla- 
proth in the following manner : three hun- 
dred parts of it were digested with four times 
their weight of nitric acid. This operation 
was repeated, and the two acid liquids mix- 
ed. The undissolved residuum was 188 parts. 
The nitric solution was green, and when 
common salt was added toi.t, muriat of silver- 
precipitated. The solution being now super- 
saturated with ammonia, 9.5 parts of a fieaky 
red precipitate were obtained, which was 
found to be composed of silica, alumina, and 
iron, by dissolving it in muriatic acid, and 
proceeding by the rules laid down in the first [ 
GRES. 
[ section. A polished iron plate precipitated 
I from the nitric solution 69 parts of copper. 
The 188 parts of residuum were boiled 
with six times their weight of muriatic acid; 
105.5 parts remained undissolved, which 
were sulphur and silica. The muriatic acid 
solution being concentrated, yielded a little 
muriat of silver. Being diluted with a large 
portion of water, a white powder precipitat- 
ed, which weighed 97.5 parts, and was oxide 
of antimony. 
4. tied copper ore has only to he dissolved 
in muriatic acid, and the copper precipitated 
by a plate of iron; 88 parts of the precipi- 
tated copper being equivalent to 100 of the 
orange oxide of which the ore is composed. 
5. The analysis of the oxides and carbo- 
nats of copper scarcely requires any remarks. 
The water and carbonic acid must be esti- 
mated by distillation iu close vessels, and 
collecting the products. The ore may then 
be dissolved in nitric acid, and its copper as- 
certained as above. 
6. Arseniat of copper was analysed by Mr. 
Chenevix, in the following manner : the ore 
was dissolved in diluted nitric acid, and ni- 
trat of lead poured in. The solution was eva- 
porated till a precipitate began to appear, 
and then mixed with alcohol. Arseniat of 
lead precipitated. One hundred parts of this 
salt indicate 33 of arsenic acid. The copper 
was separated from the nitric acid by boiling 
it with potass. 
Ores of iron. Notwithstanding the great 
variety of iron ores, they may be all, as far as 
analysis is concerned, arranged under three 
heads; namely, 1. Sulphurets ; 2. Oxides ; 
and 3. Salts. 
1. Pyrites, or sulphureted iron, may be 
treated repeatedly with boiling nitric acid 
till the sulphur is acidified. Muriatic acid is 
then to be added, and the digestion continued 
till the whole is dissolved. Muriat of barytes 
is then to be added to precipitate the sulphu- 
ric acid; 100 of the dried .precipitate indi- 
cate 14.5 of sulphur. If the solution con- 
tains only iron, it may be precipitated by 
carbonat of socla, calcined to redness, and 
weighed. But if earths or manganese are 
present, we must proceed by the rules laid 
down in the first section. 
2. If the oxides of iron are pure, that is, 
contain nothing but iron, we have only to 
dissolve them in muriatic acid, and precipi- 
tate them as above. But it is very seldom 
that ores possess this perfect degree of purity. 
The iron is usually combined with manga- 
nese, alumina, silica, or with all of these to- 
gether. The analysis is to be conducted ex- 
actly according to the rules already laid 
down. 
3. The sparry iron ore may be analysed in 
the same manner, excepting only that the 
carbonic acid gas must be separated by dis- 
tillation or solution in close vessels. 
4. Arseniat of iron was analysed by Mr. 
Chenevix in the following manner : One hun- 
dred parts of it were boiled with potass till 
the* arsenic acid was separated. Nitrat of 
lead was mixed with the solution ; 100 parts 
of the precepitate indicated 33 of arsenic acid. 
That portion of the ore which eluded the ac- 
tion of the potass was treated with muriatic 
acid; the undissolved residuum was silica. 
The muriatic acid was supersaturated with 
ammonia. The iron precipitated; but the 
copper was dissolved by the ammonia, 
R r 2 
Ores of iin. 1. The sulphuret of tin was 
thus analysed by Klaproth: 120 parts of the 
ore were digested with nitro-muriatic acid; 
43 parts remained undissolved. Of these, 
30 burnt away with a blue flame, and were 
sulphur ; of the remaining 13, eight dissolved 
in nitro-muriatic acid. The undissolved live 
were heated with wax, and yielded a grain 
of iron attracted by the magnet. The rest 
was a mixture of alumina and silica. The 
nitro-muriatic solution was completely pre- 
cipitated by potass, and the precipitate re- 
dissolved in muriatic acid. A cylinder of tin 
precipitated 44 parts of copper from this so- 
lution, and lost itself 89 parts of its weight. 
A cylinder of zinc precipitated 130 parts of 
tin; so that, deducting the 89 parts of tin dis- 
solved during the precipitation of the copper, 
41 remain for the tin contained in the ore. 
2. Tin stone was thus analysed : One hun- 
dred parts of the ore were heated to redness, 
with 600 parts of potass, in a silver crucible ; 
and the mixture being treated with warm 
water, 11 parts remained undissolved. These 
11, by a repetition of the treatment with po- 
tass, were reduced to lfth. This small resi- 
duum dissolved in muriatic acid. Zinc pre- 
cipitated from the solution one-half part of 
tin, and the Prussian alkali gave a blue pre- 
cipitate, which indicated one-fourth part of 
iron. 
The alkaline solution was saturated with 
muriatic acid ; a. white precipitate appeared, 
but it was redissolved by adding more acid. 
The whole was precipitated by carbonat of 
soda. The solution, which had a yellowish 
colour, was redissolved in muriatic acid; arid 
a cylinder of zinc being inserted into the so- 
lution, 77 of tin were obtained, indicating 
nearly 98 parts of oxide of tin. 
Ores of lead. 1. Sulphuret of lead usually 
contains a little silver, and sometimes also 
antimony and zinc. It may be treated with 
diluted nitric acid, which leaves only the sul- 
phur undissolved, the weight of which is to 
be taken, and its purity determined by com- 
bustion. If antimony is present, it will either 
remain in the state of a white oxide, or if 
dissolved, it will be precipitated by diluting 
the solution with water. Muriatic'acid is to 
be added, and the solution evaporated till it 
is reduced to a small portion. Muriat of lead 
and of silver precipitate. The first of these' 
may be dissolved in boiling water, the second 
remains insoluble. West rum separated the 
muriat of silver by digesting the precipitate 
with ammonia. The liquid from which the 
muriats were separated may contain iron, 
zinc, copper, 't he iron may be precipitated 
by ammonia added in excess; the copper, 
by a plate of zinc ; the zinc may be precipi- 
tated by carbonat of soda reduced to the me- 
tallic state, and weighed; subtracting what 
had been separated from the plate of zinc. 
2. Arseniated peroxide of lead was thus 
analysed by Vauquelin: 100 parts roasted 
for half an hour; and occasionally treated with ' 
a little tallow, lost 38 parts, which were con- 
sidered as oxide of arsenic. The residue was 
treated with concentrated muriatic acid, and 
boiled in it for a quarter of an hour. The 
liquid assumed a red colour, and emitted 
abundance of oxymuriatic acid gas. A white 
needleform salt was deposited, and some of 
it was obtained by evaporation. This salt, 
dissolved iu water, and treated with sulphat 
