248 W. Gibbs and F. A. Genth 
1:1==107° 20’; 1:4@= 126° 20’; ii: 14 = 137° 21’; 0: 1i= 182° 85’ (cale. 
132° 39’); a= 10866. : 
Prof. Dana remarks that the angles are very close to those of 
Cerasine; and also to those of Scheeletine or tungstate of lead, 
if 1¢ be $ and 1 be 1z. 
The sulphate of Roseocobalt is nearly insoluble in cold water, 
but is soluble in much boiling water, and crystallizes readily as 
the solution cools. By slow evaporation, it may be obtained in 
large crystals, which, however, seldom exhibit very perfect faces. 
Ammonia in dilute solution dissolves the sulphate, giving a fine 
urple solution, from which the salt erystallizes unchanged. 
‘The neutral solution is readily decomposed by boiling, ammonia 
being evolved, and a dark brown precipitate of the hydrated 
magnetic oxyd of cobalt, Cos04+8HO, thrown down, while 
sulphate of Luteocobalt remains in solution. The decomposition 
in this case extends to the sulphate of Luteocobalt also, so that 
much less than one equivalent of this salt is obtained for two 
equivalents of the sulphate of Roseocobalt decom . 
Strong ammonia poured upon dry sulphate of Roseocobalt 
usually changes its color almost immediately from a red to @ 
buff yellow, while the liquid itself becomes red. The buff col- 
ored substance formed in this case, is the sulphate of Luteoco- 
balt; the red solution contains sulphate of Roseocobalt. 
When dry sulphate of Roseocobalt is carefully heated in 4 
porcelain or platinum crucible, ammonia is evolved, and there 
remains a lilac-red mass, which contains sulphate of Luteocobalt, 
sulphate of Purpureocobalt, and a leek-green crystalline sub- 
stance which we have called provisionally Praseocobalt. : 
We shall speak of all these reactions more fully when treating 
of the sulphate of Luteocobalt. ve 
A current of the red gas which arises from the action of nitric 
acid upon starch, and which probably consists chiefly of one 
converts an acid, neutral, or ammoniacal solution of sulp 
balt into one of the nitrate of Xanthocobalt. 
