Farmyard Manure. 19 



The comparison of these analytical results with the numbers 

 obtained in the analysis of the fresh manure, exhibits several 

 striking differences, to some of which I beg to direct attention. 



1. The well-rotten dung contains rfearly 10 per cent, more 

 water than the fresh. The larger percentage of water, it is true, 

 may be purely accidental ; but, considering the tendency of the 

 liquid excrements to sink to the lower part of the manure pit in 

 which the rotten dung accumulates, I believe rotten dung will 

 always be found moister than fresh dung upon Avhich no rain 

 has fallen. 



2. Notwithstanding the much larger percentage of moisture in 

 the well -rotten dung, it contains in its natural state, with 75^ per 

 cent, of water, almost as much nitrogen as the fresh dung, with 

 only 66 per cent, of moisture. Supposing both to be equally 

 moist, there would thus be considerably more nitrogen in rotten 

 dung than in an equal weight of fresh. This is clearly observed 

 by comparing the total amount of nitrogen in the perfectly dry 

 fresh and rotten dung. In the former it amounts to 1*90 per 

 cent, of nitrogen, in the latter to 2*47. As far as this most 

 valuable element is concerned, farmyard manure becomes much 

 richer, weight for weight, in becoming changed from fresh into 

 rotten dung. 



3. During the fermentation of the dung the proportion of 

 insoluble organic matters greatly diminishes ; thus the dry fresh 

 manure contained 76 per cent, of insoluble organic matters, whilst 

 there were only 52 per cent, in the dry rotten dung. 



4. It is especially worthy of observation that, whilst the inso- 

 luble organic matter is much reduced in quantity during the 

 fermentation, the insoluble organic matter which remains behind 

 in rotten dung is richer in nitrogen than an equal quantity of in- 

 soluble organic matter from fresh dung. Thus 76 per cent, of 

 insoluble organic matter of fresh dung contain 1*46 per cent., 

 whilst 52 per cent, of it from rotten dung very nearly contain the 

 same quantity, namely, 1*26. Or, 



100 parts of insoluble organic matter \ -, n o 



from fresh dung contain .... . . / 1>92 P er cent of mtr g en - 



100 parts of insoluble organic matter ) 0.4-1 



from rotten dung contain . . / " " 



5. On the other hand, the relative proportion of insoluble 

 inorganic matters increases much during the fermentation of the 

 dung, since dry fresh dung contains about 12 per cent, of 

 insoluble mineral matters, and dry well-rotten dungs 26'8 per 

 cent., or more than double the amount which is found in fresh 

 dung. 



6. But perhaps the most striking difference in the compo- 



