[macfarlane] loss OF SUBSTANCES IN MOSS MANURE 65 



previous experiments, and was carefully analysed as to its nitrogen con- 

 tents. To the mixture there was added from time to time successive 

 Guantities of urine, but always in such measure as not to supersaturate 

 the moss. The basket was placed in a porcelain capsule so as to pre- 

 vent loss from dripping. Xot only did evaporation take place from 

 the moss as it stood, but it was from time to time emptied out of the 

 wire basket and thoroughly mixed. In this way every opportunity was 

 given to the mixture to tlirow oiï its moisture. The experiment was 

 carried on for about three weeks, and then a comparison made as regards 

 the nitrogen contained in the materials used, as well as in the product. 

 The former were as follows: — 



, Grammes 



Nitrogen 

 410 grammes moss manure which, after drying would 



have amounted to 300 grammes with 32 p^v cent. 



Nitrogen 9 60 



150 grammes Welland Moss witli loO per cent Nitrogen 234 



2206 grammes urine containing 82 per cent. Nitrogen. . 18 09 



Total 30 03 



The product of the experiment weighed 483 grammes, and con- 

 tained 3-22% nitrogen, equal to 15-55 grammes, or 15-48 grammes less 

 than in the materials used. Since, however, the nitrogen in the 

 original moss manure and in the moss litter must be regarded as fixed, 

 it follows that the loss must have been sustained by the nitrogen of the 

 added urine, amounting to 18 -09 grammes. Of this only 3 •61 was 

 recovered, thus showing a deficiency of 14 '48 grammes, or 84 -04 p.c. of 

 the nitrogen of the urine. This must have escaped along with the 

 2283 grammes of water evaporated in the course of the experiment. 



The foregoing trial was repeated more than once under slightly 

 different conditions, and results invariably obtained w^hich went to prove 

 that almost the whole of the nitrogen contained in urine is lost when 

 the latter is absorbed by moss litter, and its water allowed to evaporate 

 spontaneously with unlimited access of air. The urea is perhaps com- 

 pletely resolved into carbonic acid and ammonia, but the odour of the 

 latter is not very strongly manifested, and possibly some of the nitrogen 

 of the urea may have escaped in the free state. 



A series of experiments was next undertaken for the purpose of 

 retaining the nitrogen as ammonia by mixing with the moss litter sub- 

 stances containing salts and acids capable of fixing the volatile alkali. 

 The urine was absorbed by the moss litter, and allowed to dry gradu- 

 ally as above described. It is unnecessary to give all the particulars 

 regarding these trials, but it may be stated that in all cases sufficient 



Sec. in., 1904. 5. 



