on the Ammonia-cobalt Bases. 239 
reduced copper, to pti ir completely the great quantity of 
her 
ammonia-cobalt salts is very difficult. Nitrate of silver, it is 
true, precipitates chlorine from most of its combinations in these 
salts, but the precipitation is never complete, because the chlorid 
of silver is somewhat soluble in the ammonia-cobalt chlorids, 
forming with them peculiar double salts. By long boiling with 
free nitric acid in the solution, nearly all the chlorine may be 
determined as chlorid of silver, but very accurate results cannot 
be obtained in this manner. ‘The best method consists in ignit- 
ing the chlorid with lime in a combustion tube, in the manner 
usually practised with organic bodies. In some cases, however, 
Wwe have obtained very good results by decomposing the solution 
grea 
Carbon.—This element is best determined by the usual process 
n, because, copper reduced from the oxyd by hydrogen, 
alway 8 contains water, which it is difficult to separate. digas 
__ Nitrogen.—No element has presented such difficulties as nitro- 
8en. We have found it impossible to obtain-results within two 
or three per cent of the truth by employing the old methods of 
analysis, that of Dumas for instance. The quantity of 
