Dr Fyfe’s Analysis of Sulphate of Nickel and Copper. 209 
ly of a brownish colour appeared. It was this that led me 
to suspect the presence of copper, a suspicion which was con- 
firmed by other experiments ; thus, when a solution of sul- 
phuretted hydrogen was added to that of the salt, a black 
powder fell, which, when dissolved in nitric acid, afforded a 
blue precipitate with the ammonia, soluble in excess of the 
alkali, and yielded also a brown precipitate with the prussiate 
of potassa. The fluid from which the black powder was thrown 
down, gave a greenish precipitate on the addition of ammonia, 
which disappeared on adding more of the alkali, converting the 
colour of the fluid to blue. 
These experiments indicate the presence of sulphuric acid, 
nickel, and copper, which, with water of crystallization, are the 
only substances I could detect in the salt. That this is its com- 
position, is also confirmed by the analysis, made with the view 
of ascertaining the proportion of its ingredients, in which I 
employed sulphuretted hydrogen as the means of separating the 
copper from the nickel ; the latter not being precipitated by 
this substance. 
Ten grains of the salt were exposed to a gentle heat, till the 
whole of the water of crystallization seemed to be driven off, 
after which they weighed 7.05 grains, making the loss 2.95. 
When sulphate of nickel is subjected to a high temperature, 
it undergoes a slight decomposition, and a small portion of in- 
soluble subsulphate is formed. The saline matter left, after 
the exposure of the ten grains of the salt to heat, in the above 
experiment, was entirely soluble in water, proving that decom- 
position had not taken place. 
The white precipitate occasioned by nitrate of baryta, after 
exposure to a red heat, weighed 7.52 = 2.55 of sulphuric 
acid. 
The black powder thrown down by sulphuretted hydro- 
gen, after exposure to heat, was dissolved in nitric acid, and 
then afforded, with potassa, a precipitate, weighing 0.53 = oxide 
of copper. To the fluid from which the copper was remov- 
ed, potassa was added ; the precipitate weighed 3.95= oxide 
of nickel. The component parts of the salt, then, according to 
this analysis, are, 
VOL. v. no. 9. JULY 1821. 
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