350 Contributions to Chemistry from the 
20° C 
Zinc.—W hen solutions of gulphate of zine and hyposulphite 
-140° C0, 
tated under ordinary atmospheric pressure from boiling solutions. 
When a boiling solution of sulphid of sodium is added to a 
boiling solution of sulphate of nickel or cobalt, the sulphids are 
2. On the determination of nitrogen by weight. 
Bunsen” has given a method of analyzing nitrates and nitrites 
salt in a single analysis, This method consists essentially im 
igniting the salt in an atmosphere of nitrogen gas, absorbing the. 
oxygen evolved by metallic copper, and collecting the water 12 
a chlorid of calcium tube. The nitrogen in the salt is given by 
he loss of weight in the apparatus. ‘a 
_ In those analyses of nitrates or nitrites in which it is only de- 
sired to determine the nitrogen, the following process may 0@ 
employed with advantage. A hard glass tube, about six inches 
in length, is sealed at one end, and its volume determin it 
filling it with mercury and pouring this into a graduated ve ra 
The tube is to be carefully dried and weighed with a good cork+ 
itis then to be filled with finely divided metallic copper, PT& 
jared by reduction of the oxyd, so as to ehable the operator t0 
judge of the quantity necessary. The salt to be analyzed 8 
then weighed and mixed with the metallic copper, either 1n # 
* Ann. der Chemie und Pharmacie, lxxii, 40. 
