I 076
GEO. W M . S I I K G E N T .
K ESYLTS. Chalcupyritc.
Iron. Per c e n t .
IrO!l.
(:rain
Grain.
0.5E00
0.1746 0 . i 7\50
0.jSOiI
p.ro .lo. I T
T h e question has been asked whether it is not possible, in a case like that of chalcopyrite, to render the origiiial solution of the niineral ammoiiiacal and, not regarding the precipitated ferric hydrate, proceed n i t h the electrolytic deposition of the copper. l l a n y have felt that there was danger of iron entering into the tieposit of copper, lvhile others have declared that such a condition was nut to be feared. 1)uring the past winter numerous tests of this question have been made in this laboratory, working \\.it11 chalcopyrite. It has been found that if platinum dishes be cxiployctl as cathodes to receive the copper, the latter has invaria1)l~.lxen contaminated \\it11 iroii, but that if platinuiii cyliric1t.r.. . (Ii1y)iiig into the aininoiiiacal solution contained iii beaker-glasses. \\ere used for cathodes the copper clcpositul iipoii them \vas free from iron. The writer has had the assistance of Meosrs. J . H. Graham aiicl I:. 1'. Il'alker in the experimental part of this study and would Iic~rcacknowledge his iiidehtcdiicss to them.
T H E USE OF POTASSIUM-FERRIC CHLORIDE FOR T H E SOLUTION OF S T E E L IN MAKING T H E DETERnINATION OF CARBON. 13Y
