240 Farmyard Manure. 



tion in the fact tliat during an active fermentation organic acids 

 are formed which fix the ammonia, while the same acids are not 

 so readily produced in the absence of the requisite amount of 

 moisture. 



At the same time it should be borne in mind that ammonia 

 escapes more readily from a partially-dried substance than one 

 saturated with moisture ; and as the manure-heap under shed on 

 keeping became much drier than the heap exposed to the weather, 

 the free ammonia had a better chance of being dissipated into the 

 air. 



The August and November, 1855, analyses on account of the 

 accidental impurities, do not give a fair representation of the 

 changes which may have taken place during these periods. 



There should be of course the same total amount of mineral 

 matters at the end of the experimental year which occurs in the 

 manure when first placed under cover. Omitting the fractions we 

 have in November, 1855, 182 lbs. of mineral matters, and on the 

 30th of April, 210 lbs., or a difference which is not greater than 

 might have been expected in two analyses of the same sample of 

 manure. 



But assuming the samples, which have been taken for the 

 August and November analyses, to represent fairly the composi- 

 tion of the whole heap, we would have no less than 343 lbs. of 

 mineral matters in August, and 312 lbs. the following November. 

 Now this cannot be the case, and it is therefore plain that the 

 excess of mineral matters must be due to accidental admixture of 

 dirt to the dung. Such an admixture of course will reduce the 

 amount of nitrogen and organic matters in the analyses : but if 

 a correction be made for this palpable inaccuracy it will be found 

 that after the 30th of April the heap under shed sustained but 

 a very trifling loss in nitrogen and organic matters. 



Leaving the reader to make this calculation for himself, I 

 append a Table which will furnish the data for similar calcu- 

 lations (p. 241). 



Experimental Heap (No. III.), fresh Farmyard Manure, spread 

 in an open Yard. — Mixed horse, cow, and pig dung. 



Having furnished the reader with a complete anal} sis of each 

 experimental heap with the exception of the manure spread out 

 in an open yard, I thought it desirable to submit the manure 

 No. III., the originally fresh farmyard manure, to a complete 

 organic and inorganic analysis, after it had been exposed to the 

 influence of rain, sun, and wind for a period of six months. The 

 results of this examination are incorporated in the following 

 Tables, 



