1906.] A New Source of Nitrates. 477 



In treating the peat with a solution of sulphate of ammonia, 

 it was found necessary to use a very weak solution (7^ grams 

 to the litre), which resulted in a solution containing about i per 

 cent, of nitrate, a proportion which did not admit of being 

 concentrated economically. But the investigations showed 

 that nitrification continued in solutions heavily charged with 

 nitrate even up to 22 per cent., so that the practice was adopted 

 of adding fresh salts of ammonia to the already nitrified solution 

 and passing it repeatedly through the peat, thus gradually 

 enriching the solution in nitrates. The liquid became more 

 and more charged with nitrate, but not with ammonia, the 

 proportion of which is never allowed to become high enough 

 to interfere with the activity of the nitrifying organisms. The 

 results showed that the liquid contained 8'2 grams per litre on 

 its first passage through the peat, and 417 grams per litre after 

 passing through five times. This is said not to be the limit of 

 absorption, but to represent the point of economical ex- 

 traction. 



If this method of manufacturing nitrates were carried out on 

 the peat lands themselves, peat would serve to furnish the 

 material necessary for maintaining the heat of the nitrate bed 

 and for evaporating the liquid. 



Messrs. Muntz and Laine were also led to consider whether 

 peat could not furnish in addition the ammonia necessary for 

 the operation, as it contains from 2 to 3 per cent, of its dry 

 weight of nitrogen. They found, however, that in the ordinary 

 method of treating peat for the distillation of pyroligneous acid 

 and other products, the bulk of the nitrogen was left in the 

 coke residue. By treating the peat in a current of superheated 

 steam instead of by the dry method, they have succeeded in 

 extracting 161 to 179 per cent, of the nitrogen from peat 

 containing 2*03 per cent. If this method of producing nitrogen 

 proves a commercial success it will add to our manurial 

 resources, whereas the nitrification of sulphate of ammonia by 

 peat is not likely to have any very direct importance for 

 agriculture. Nearly all soils nitrify freely, and the relative 

 prices of sulphate of ammonia and nitrate of soda show that 

 the artificial nitrification of sulphate of ammonia would seldom 

 be a profitable business. 



