300 
CYANIDE OF POTASSIUM. 
oxide and acids of antimony may be reduced to the metallic 
state. 
All these reductions are effected at a feeble red heat, not 
visible in daylight; and hence the peculiar advantage that no 
loss can arise from the volatilization of any portion of the re- 
duced metal. 
The sulphurets of tin and antimony are reduced by a gentle 
fusion with cyanide of potassium, by means of a lamp, in a 
porcelain crucible, with much greater facility than the corres- 
ponding oxides. The scoria contains sulpho-cyanide of po- 
tassium. This reductive property is possessed by the cya- 
nide, not only in the dry, but also in the state of solution. If, 
for example, we mix it with alloxane, in a few seconds there 
is formed a heavy, crystalline, scarcely soluble precipitate of 
dialurate of potassa. 
Cyanide, of Potassium as an Jlgent of Separation. 
Nickel, cobalt and manganese, are so much alike in their 
properties, that a rigorous quantitive separation of these me- 
tals present great difficulties. 
It is only under one form of combination that nickel differs 
from cobalt, in a manner w T hich we can take advantage of as 
a means of separation. Heated with cyanide of potassium 
and hydrocyanic acid in excess, the oxide, or a salt of cobalt, 
or the chloride, &c, is converted into cobalto-cyanide of po- 
tassium, whose solution in water is not in the least decom" 
posed by ebullition with hydrochloric, sulphuric, or nitric 
acid, as was ascertained by L. Gmelin. 
The oxide and salts of nickel are precipitated by the cyanide 
of potassium; this precipitate dissolves in an excess, causing 
a yellow color; and the double combination of cyanide of 
nickel and cyanide of potassium is not completely decom- 
posed by acetic acid, but readily by diluted sulphuric acid, 
and the cyanide of nickel is precipitated. 
If to a mixture of the salts of nickel and of cobalt, acidu- 
lated with free acid, cyanide of potassium in excess be added, 
