250 W. Gibbs and F. A. Genth 
tion of nitrate of Reseocobalt, but is not indispensa 
The preparation of pure nitrate of Roseocobalt is attended 
with difficulty, as the precipitated crystallime nitrate almost 
always contains a little nitrate of Luteocobalt. It is best to dis- 
solve the crude nitrate in water, to which a little ammonia has 
ence of nitrate of ammonia facilitates the oxydation and forma: 
le. 
color of the large and small crystals of the same substance is 
very commonly observed in the ammonia-cobalt compounds, 
cult to obtain a pure salt in this manner. Nitrate of copper also 
gives nitrate of Roseocobalt with chlorid of copper, when mixed 
with an equivalent proportion of chlorid of Roseocobalt, but 
the purification is difficult. Finally, a pure nitrate may be pre- 
salt, like the se ere crystallizes in forms belonging to the di- 
metric system. Fig 
combinations, fig. 5 is a very rare form, which was obtained only 
once. 
5. 6. 
:1 {over the base) ==82° 40’. Whence 0:1 (not observed) = 186° 20/5 7:2 
1:1 
==131° 
