46 Farmyard Manure. 



much more sensibly in the period of active fermentation, in 

 which, however, we have seen that scarcely any nitrogen is dis- 

 sipated. In the August and November analyses, moreover, it 

 will be observed that not only the amount of soluble organic 

 matters, and with it that of the nitrogen, decreases, but that the 

 soluble mineral matters, which in April amount to 57 '88 Ibs. in 

 the entire heap, became reduced to 39'16 Ibs. by the 23rd of 

 August. Now, this decrease in soluble mineral substances can 

 only be ascribed to the rain which fell in this period, and it is 

 plain that the deteriorating influence of heavy showers of rain 

 must equally affect the soluble nitrogenized constituents of dung. 

 That this is really the case will appear still more conspicuously 

 by the analysis of experimental heap No. III., to be mentioned 

 hereafter. 



It may perhaps appear strange to the reader that the total 

 amount of dry matter in the manure is greater in November, 

 1855, than in August, and likewise that there is a good deal 

 more insoluble mineral matter at the end of the experimental 

 year than at the beginning. In explanation of these apparent 

 inconsistencies, I would observe that the increase in insoluble 

 mineral matters is accounted for in the difficulty of shovelling 

 the manure into the dung-cart without mixing with it each time 

 the weighing is made a certain portion of the soil on which the 

 heap is placed. It must likewise be borne in mind that it is 

 almost next to impossible to incorporate mechanical impurities 

 so thoroughly with the dung that differences amounting to 2 or 

 3 per cent, in the amount of insoluble matters may not occur in 

 the analyses of 2 samples taken from the same heap. In the 

 percentic composition of farmyard manure such differences ap- 

 pear inconsiderable, but when applied to the whole heap they 

 strike us as being great. In short, it is impossible to determine 

 accurately the total amount of insoluble mineral matters in the 

 whole heap. The general deductions, however, which may 

 legitimately be made from the foregoing analyses are not in any 

 perceptible degree affected by this unavoidable source of inac- 

 curacy ; but it is well to remember not to dwell too much on 

 minor differences which perhaps may strike the reader ; some such 

 differences may be due to purely accidental causes. 



Before I pass over to the experimental heap No. II., I would 

 direct attention to the subjoined Table, in which I have calcu- 

 lated the loss or gain which the experimental heap No. I. sus- 

 tained in the different constituents in the course of the year. 

 Where there is a gain the sign * is prefixed to the number to 

 which it applies ; all numbers without this sign express loss in 

 Ibs. and in fractions of Ibs. The loss for the whole heap has been 

 calculated for 100 Ibs. of fresh manure, as well as per ton. 



