324 W. Gibbs and F.. A. Genth 
be purified, though with difficulty, by recrystallization. Their 
constitution is represented by the formula 
5NHs.Co20s, 2SO3, 20203+38HO 
as appears from the following analyses: 
077433 grs. gave 0°3315 grs. sulphate of cobalt = 1697 per cent cobalt. 
13912 grs. gave 0°9535 grs. sulphate of baryta = 2350 “ sulphuric acid. 
1°6895 grs. gave 11564 gra, * # ==2349 “ — sulphuric acid. 
2°7'102 grs. gave 0°7070 grs. carbonic acid = 2088 “ oxalic acid. 
20198 grs. gave 340 ¢.c. of nitrogen at 14°5 C. and 763"™-01 (at 15° C.)==3184 | 
ce. c, at 0° and 760% == 19°78 per cent nitrogen. 1 
The formula requires 
Eqs. Calculated. Found. 
5 17-00 
Sulphuric acid, - 2 28°05 23°49 23°50 
Oxalic acid, 2 20°74 20 
Nitrogen, - 5 20°17 19-78 
The reactions of this remarkable salt resemble closely those of : 
the acid sulphate. It has an acid taste and reaction, gives 20 
precipitate with oxalate of ammonia, or cobaltidcyanid of potas- 
sium, and yields chlorid of Purpureocobalt by boiling with an 
excess of chlorhydric acid. The formula of this salt may be = @ 
written in various ways. In the first place, we may considerit 
as a double salt represented by the formula : 
5NHs.Co203, 4803+5NH:s. Coz20s, 4020s +6HO. 
The advantage of simplicity is evidently in favor of the for- 
a we have adopted. We may also consider it as represen 
5NHs.Co20s3, 2803+2C:03, HO+HO. ‘ 
__ In this case the salt should have a strongly acid taste which 
it has not. On the whole the formula 
2803 
5NHs.Co20s 130203+8HO 
appears to deserve the preference. 
NEUTRAL OXALO-SULPHATE OF PURPUREOCOBALT. 
When ammonia is added to a solution of the acid oxalo-sul- 
phate just described, a fine violet-red color is produced, and 
no more ammonia be added than is sufficient to completely nev 
tralize the acid reaction, the liquid yields, on evaporation, beau- 
tiful red prismatic crystals of a neutral salt. The neutral © 
sulphate is much less soluble in water than the acid salt, and mad , 
a purely saline taste: it is easily ag re by boiling. 
formation of this salt is represented by the equation 
5NH2.Co20s, 280s, 2C203-+ 2NHiO=5N Hs. Co20s, SOs, 
NHiO, 80s--NHi0, C203. 
