4 Copper , 
glass of borax, with a drop or two of oil ; the mass thus 
formed, is to be put into a sound earthen crucible, a co- 
ver is to be luted on, and the whole is to be placed in a 
good wind furnace. The heat should be moderate for the 
first quarter of an hour, to allow the borax time to com- 
bine with the earthy impurities of the ore ; then a mode- 
rate white heat is to be applied for about twenty minutes. 
After this, the crucible being withdrawn and cooled, is 
to be carefully broken, and will be found to contain a 
button of copper, covered by vitreous scoriae. The puri- 
ty of the copper thus procured, is to be estimated from its 
colour, softness, malleability, and tenacity ; after which, a 
part of it may be cupelled with pure lead, in order to as- 
certain whether it holds any silver or gold. If the ore con- 
tains sulphur, but no arsenic, it may be mixed with half 
Its weight of charcoal, and roasted on a test, without be- 
ing previously heated in the crucible. If the ore contains 
neither sulphur nor arsenic, it should be first moderately 
Ignited in a covered crucible, to drive off any moisture, 
and may then be treated with sand, alkali, borax and 
lampblack, as already described. 
The proper analysis, by means of liquid menstrua, is 
however much more accurate than even the most careful- 
ly conducted assay, and the general mode of proceeding 
with the ores of copper is, upon the whole, very simple. 
The copper, together with the other metals with which it 
may happen to be mixed, is to be separated from the silex 
and sulphur, by means of an acid, the other metals are 
then to be got rid of by their appropriate reagents, and the 
copper is then to be procured either in the state of green 
earbonat, of black oxyd, or of pure metal ; of the first, 
180 parts are equivalent to 100 of metallic copper ; and 
of the second, 100 parts contain 80 of metaL 
Previously to undertaking an analysis, a part of the 
specimen, under examination, should be subjected to the 
usual reagents, in order to ascertain, not indeed the pro- 
