56 Dr Monckman, Action of Copper Zinc Couple [Feb. 24, 



capacity of the whole as small as possible, the current of steam 

 was kept very gentle and the water in the outside vessel quite 

 cold, E contains the granulated oxide of copper and F the 

 receiver. 



After passing the gas through B, C, D, E for 18 hours it was 

 joined up to F, and sufficient gas sent through to force the water 

 in the receiver down about three inches below the surface of the 

 water in the outer vessel. It was then stopped and the clip G 

 closed to prevent steam passing back into B. 



The liquid in C was then boiled gently for three hours, the 

 quantity of gas in the receiver was prevented from becoming 

 too great by carefully heating the oxide in E. Finally by a 

 current of hydrogen from A the whole of the gas was swept out 

 of the tubes ; as before most of this was absorbed by heating 

 the oxide in E, so that a considerable quantity was passed through 

 the tubes B, C, D. The clip H was next closed and the quantity 

 of N in the receiver determined. 



In order to decompose any nitrate or nitrite that might 

 remain in C, HKO was added to the solution and the whole 

 boiled until all the salt was decomposed, after which the ammonia 

 was determined. 



The results appear in the following table : 



The weight of KN0 3 in the solution was "225 grms. 



of which the N would weigh "03118 grms. 



The result of the previously described experiment was 



N evolved as gas "02304 grms. 

 N evolved as NH 3 -Q09 „ 

 Total -03204 



Too much by '00086 grms. 



Given in per cent, of the salt used : 



calculated, N is 13861 per cent., 

 found, N is 14-24 „ 



excess, '379 „ „ 



The only other salt tried by me was the nitrate of ammonia, 

 which gave nitrite on gently boiling with the couple. As that 

 salt is decomposed into N and H 2 on boiling I did not consider 

 it necessary to prove the evolution of N in this case. 



In conclusion I wish to say that no equation has been given, 

 because the proportion of NH 3 evolved so evidently depended 

 upon the temperature, or rate of boiling, that it would be mis- 

 leading; the reaction may be represented however by the two 



