W. Gibbs on the Hexatomie compounds of Cobalt. 195 
orange-colored crystalline precipitate, which may be dissolved 
in boiling water, but not without partial decomposition. The 
crystals have made it of great service in my investigations, 
especially in distinguishing salts containing 
from those which contain Co,(NO,) Compounds of ammonia- 
cobalt-nitrite with barium, strontium, etc., are easily formed by 
ammonja, The formation of the salt Co.(NHs),(NO.)sK, may 
be expressed by the equation 
2CoCl,-4NH,Cl4+-8KNO,+-0=Co, (NH,),(NO,)sK2+ 
6KCl+2HCl+OH,, 
if we suppose oxygen to be absorbed from the air. Tn conse- 
quence, however, of the formation of free chlorhydric acid, N,O; 
is set free, and it is much more probable that this is reduced by 
the nascent-hydrogen; so that we have 
N,0,+2H=2N0+0H “ 
