2KX Dr Fyfe T s Analysis of Sulphate of Niskel and Copper ... 
Water of crystallization, 
2.95 
or 29.5 
Sulphuric-acid, - 
2.55 
25.5 
Oxide of nickel, 
3.95 
39.5 
Oxide of copper, - '' - 
0.53 
5.3 
9.98 
99 8 
Loss, 
2- 
2 
10.00 
100.0 
ight deficiency, I have no 
doubt, 
is in the 
crystallization, for as I was afraid that, by exposing the salt to 
too strong a heat, it would undergo decomposition, the whole 
of this substance may not have been driven off. The following, 
therefore, I consider to be the true composition of the salt. 
Water of crystallization, - - 29.7 
Sulphuric acid, * - 25.5 
Oxide of nickel, - - 39.5 
Oxide of copper, - - 5.3 
100.0 
Considering the proportions in which the ingredients exist in 
this substance, I am induced to regard it as a peculiar triple salt; 
and that the copper is not merely accidentally mixed with the sul- 
phate of nickel ; for if we combine the oxide of the former metal 
with its due quantity of sulphuric acid, we shall find that there 
is not enough of this acid left to saturate the oxide of the latter. 
Sulphate of copper is generally stated to be composed of 31.38 
of acid, and 32.32 of oxide, with water of crystallization; 
5.3 of oxide, therefore, take 5.1 of acid, leaving 20.4. In sul- 
phate of nickel, according to Thomson, 25.6 of oxide are uni- 
ted with 28.98 of acid, 39.5 of the former then acquire 45.13 
of the latter, but there are left only 20.4. Leaving even the 
copper out of consideration, there is not enough of acid to satu- 
rate the oxide of nickel, according to the constitution of the sul- 
phate of this metal, as stated above ; besides, in the salt, the 
analysis of which has been given, the water of crystallization is 
far inferior to what it is in sulphate of nickel, as in the latter 
it amounts to about 45 in the 100 parts. 
Edinbuhgh, 1 
June 1821. [ 
