[macfarlane] conservation OF NITROGEN IN MANURE 41 



necessary to make trials towards the same end but allowing the water 

 to evaporate spontaneously. Half a dozen of these were made with such 

 indifferent results as to render their description a most ungrateful task. 

 Still the duty of recording has to be performed, in order that others may 

 be saved from making abortive experiments. The following are selected 

 as sufficient for the purpose. 



1\'. In a round graniteware dish 200 grammes Welland Moss were 

 treated with successive portions of a mixture of urine and sulphuric acid, 

 from the 23rd x\pril till the 5th Sept., 1904. Each addition of urine 

 with its proportion of acid was only made after the one preceding it had 

 evaporated and left the moss in a comparatively dry condition. The 

 materials used consistea of : — 



Grammes Nitrogen 



200 grammes Moss litter with 1.56 per cent N . . 3.12 



8493 grammes Urine with 0.82 per cent jST 28 . 64 



106 grammes Oil of Vitriol .... 



Total 31.76 



The product weighed 505 grammes and contained 3.91 per cent 

 nitrogen or 21.31 grammes, shewing a dsfficiency of 10.45 grammes 

 or 23.9 per cent. A second sampling was done and the nitrogen again 

 determined including that of any nitric acid that might have been 

 formed. In this case the total nitrogen in the product amounted to 

 21. ST grammes shewing about the same deficiency. This loss took place 

 even with the use of a fully sufficient quantity of sulphuric acid to fix 

 the ammonia corresponding to the original nitrogen. 



In the preceding experiment the spontaneous evaporation was 

 allowed to proceed so far as to leave the moss comparatively dry previous 

 to each new addition of liquid. The following trials V & VI were per- 

 formed in such a manner as to keep the moss always saturated with 

 liquid. The following is a statement of the nitrogen used and re- 

 covered : — 



Materials Used (V) 



Grammes Nitrogen 



344 grammes Moss with 1.56 per cent N 5.36 



6500 grammes Urine with 0.82 per cent N 53.30 



115 grammes Oil of vitriol .... 



Total 58.66 



