7 
Copper, 
lyzecl by first moderately heating them, in order to drive 
off and thus estimate the water, and then digesting the re- 
sidue in dilute nitric acid, by which it will be entirely dis- 
solved ; nitrat of lead is then to be dropped in as long as 
it occasions any precipitate, and this latter being remov- 
ed, the fluid is to be evaporated nearly to dryness, after 
which, warm alcohol is to be added, which will take up 
the whole, except a white powder ; this powder, and the 
precipitate on the addition of nitrated lead, are arseniat of 
lead, 33,66 per cent, of which is arsenic acid. The alco- 
holic solution is then to be evaporated nearly to dryness, 
and then to be digested with ammonia, which will take 
up the copper, leaving behind any oxyd of iron that may 
have happened to be contained in the ore. The ammo- 
niu ret of copper, being decomposed by caustic potash, 
gives the copper in the state of black oxyd, which is that 
in which it exists in the ore. 
The analysis of mnriat of copper is very simple. It 
was thus effected by Klaproth. The ore, being pulver- 
ized, was dissolved in cold nitric acid, with the exception 
of 1,5 per cent, of oxyd of iron ; the solution being then 
diluted, nitrat of silver was added, till it occasioned no 
further precipitate ; the lima cornea thus obtained indicat- 
ed, according to the known proportions of this salt, the 
amount of muriatic acid in the ore. The nitrous solution 
was then decomposed, and the copper obtained in the me- 
tallic form, by means of a bar of iron. 
Phosphat of copper was thus analyzed 'by Klaproth. 
On digestion in nitric acid, the whole was taken up ex- 
cept a few grains of quartz ; the excess of acid in the so - 
lution was then saturated by potash, and acetite of lead 
avas poured in till it had quite ceased- to occasion any pre- 
cipitate ; the phosphat of lead, thus obtained, was sepa- 
rated from the solution, and sulphat of soda was added to 
decompose and precipitate the small excess of acetite of 
lead which had been made use of. A little sulphuric acid 
