54 ' 
Copper . 
were put into it ; in a very short time after, a considerable 
flame took place, and the copper became red ; when the 
flame ceased, the crucible was removed from the fire ; 
after cooling, the copper was very brittle, of a fine dark 
red colour, and presented a silky striated fracture ; it weigh- 
ed 2 lbs. 10 oz. The sulphuret thus formed, was divided 
into two equal parts, one of these was occasionally moist- 
ened with pure water, and the other with water acidulated 
with the sulphuric acid. The first part did not effloresce ; 
notwithstanding every care during thirteen months, there 
was not the least appearance of vitriolization : the second 
parcel effloresced, and by occasionally moistening it with 
the acidulated water, nearly 5lbs . of the sulphat of copper 
was obtained from it. 
It is said that the quantity of sulphur may be lessened 
by projecting it on the copper heated to redness. 
When the third method is made use of, wells are dug 
in proper situations in such mines as are charged with cu- 
preous waters, into these the waters are conducted from 
different parts of the mine ; it is only necessary to evapo- 
rate them, and to set them by to crystallize. 
The fourth method will certainly furnish a very pure 
salt. As metallic copper is insoluble in the sulphuric acid 
in the cold, a boiling heat is made use of by some to ef- 
fect the combination. Other manufacturers oxyde the 
copper by exposing it to heat before they place it in the 
acid. Or dissolve the oxyd of copper at once in sulphu- 
ric acid. 
Sometimes the sulphat of copper is contaminated with 
a mixture of the sulphat of iron (copperas.) This circum- 
stance will make it unfit for most purposes. The presence 
of this last is ascertained by dissolving a portion of the 
suspected salt in water, and adding the infusion of galls 
to it ; if there be any iron in the solution a black colour 
* 
will be produced. 
