Copper* 
5 
portion, but the nature of the ingredients of which it con.- 
sists ; and, in few cases is this more necessary than in the 
analysis of the ores of copper, both as they are so nume- 
rous and so various in their composition. This previous 
examination being duly performed, the analysis may be 
conducted in the following manner : 
For the analysis of the pyritical , and other sulphurized 
ores of copper , provided they contain neither silver nor 
lead, take 200 grains of the pulverized ore, and digest it 
at a boiling heat with muriatic acid, (adding occasional!? 
a few drops of nitric acid) till every thing soluble in this 
menstruum is taken up. Of the insoluble portion, a part, 
consisting chiefly of sulphur, will be found floating on the 
liquor ; and this being washed, dried, and weighed, is to 
be ignited on a test, by which the sulphur will be burnt 
off, and its amount may be estimated from the loss of 
weight sustained by the process. The incombustible 
residue is to be digested in a little warm muriatic acid, 
and what remains insoluble, is to be added to the other 
insoluble residue. The muriatic solutions being mixed 
together, the whole is to be decomposed by carbonated 
potash, and the precipitate, hence resulting, is to be di- 
gested in repeated portions of caustic ammonia, as long 
as this latter acquires any blue tinge. The whole of the 
copper, and nothing else, will thus be taken up by the 
ammonia, from which it may be obtained in die state of 
black oxyd, by the addition of a little caustic potash, and 
a boiling heat. The residue, insoluble in ammonia, con- 
sists of oxyd of iron, with perhaps a little alumine, which 
may be separated by caustic potash, the alumine alone 
being soluble in this fluid. Finally, the portion insoluble 
in muriatic acid, may be considered as little else than si- 
lex. 
The ores which, besides copper , sulphur , and iron, con- 
tain silver, lead , and antimony , may be thus analyzed. 
The ore, reduced to fine powder, is to be repeatedly clh 
