Copper* 
copper pans. On being allowed to cool the salt will crys- 
tallize. 
In some places they perform the roasting during twelve 
hours in a reverberatory furnace. 
In some countries pyrites which contain but a small 
quantity of copper are made use of to obtain both the sul- 
phur and the sulphat or blue vitriol ; for this purpose the 
ore is broken into very small pieces, earthen vessels in 
the form of tubes are charged with these, and then they 
are exposed to heat ; the sulphur comes over and is re- 
ceived in iron vessels, connected with the earthen ones 
above-mentioned ; the residuum is treated for vitriol in 
the manner recommended for roasted pyrites. 
The second method is employed in France in the fob 
lowing manner : plates of copper are steeped in water, 
they are then withdrawn and whilst wet, pulverized sul- 
phur is strewed over them ; thus prepared they are expos- 
ed in an oven heated to redness ; after remaining for 
some time in this oven they are withdrawn, and whilst 
hot they are thrown into tubs which contain water. 
These operations are repeated until the whole, of the cop- 
per is vitriolized ; when the water is sufficiently impreg- 
nated with salt, it is evaporated, &c. as above-mentioned. 
According to Newmann, cuttings or waste pieces of 
copper are stratified and cemented with sulphur. The 
cover of the cementing pot is perforated with one or tw T o 
small holes, and the cementation is continued with a gentle 
fire till the inflammable part of the sulphur is consumed. 
The matter is then boiled in water, and the liquor, after 
due evaporation, is set to crystallize. Such parts of the 
copper as remain uncorroded, are again treated in the 
manner just described. 
Chaptal fused 2 lbs. of sulphur in a crucible heated to 
redness : the crucible was constantly kept in the midst of 
the burning coals ; in this situation 2 lbs* of sheet copper 
