65 



ROYAL SOCIETY OF CANADA 



ol' the added substances was used to efïect the retention of the ammonia 

 if all the nitrogen of the urine had been developed in that form. The 

 results were as follows : — 



A mixture of equal parts of bone super- | 



I 



phosphate and double manure potash )■ 



I 



salt J 



Sulphate of magne-.ia 



Land plaster, ground 



do do 



Proportion of 

 substances to 

 Urine as 1 to 



6 11 

 8-91 

 H -36 

 6 75 

 6-32 

 10-70 



Loss of 

 Nitrogen 



p. c. 



1 p. c. 

 1 p. c. 



•5 p. c. 

 1 p. c. 

 7 p. c. 



These results lend confirmation to the idea already expressed that 

 urea in decomposing under the above described circumstances is not all 

 resolved into carbonic acid and ammonia, but that a varying quantity 

 of nitrogen escapes in the free state. The presence of acid and neutral 

 substances capable of fixing ammonia docs not prevent this, and the 

 development of nitrogen seems to be owing to the excess of air which 

 was used in these experiments. This unlimited access was of course 

 necessary for the elimination of moisture, an advantage, however, which 

 cannot possibly compensate for the loss of nitrogen. There cannot 

 be any doubt that in the ordinary treatment of barnyard manure the 

 same infiuences are at work, and that in spite of the presence of sub- 

 stances capable of retaining ammonia, losses of nitrogen take place 

 when the manure heaps are allowed too great a degree of porosity. 



This subject is far from being exhausted, and my experiments are 

 still being continued with the object of depriving moss-manure of the 

 large amount of water it usually contains without sacrificing any of 

 its fertilizing constituents. 



