180 OF MANURE. 



of lime, the weight of which varies from 9 to 28 per 

 cent., according to the fodder which the animal 

 receives ; the fresh excrements of the cow contain 

 from 86 to 90 per cent, of water. 



Human faeces have been subjected to an exact ana- 

 lysis by Berzelius. When fresh they contain, besides 

 f of their weight of water, nitrogen in very variable 

 quantity, namely, in the minimum 1^, in the maxi- 

 mum 5 per cent. In all cases, however, they were 

 richer in this element than were .the excrements of 

 other animals. Berzelius obtained by the incinera- 

 tion of 100 parts of dried excrements, 15 parts of 

 ashes, which were principally composed of the 

 phosphates of lime and magnesia. 



It is quite certain that the vegetable constituents 

 of the excrements with which we manure our fields 

 cannot be entirely without influence upon the 

 growth of the crops on them, for they will decay, 

 and thus furnish carbonic acid to the young plants. 

 But it cannot be imagined that their influence is 

 very great, when it is considered that a good soil is 

 manured only once every six or seven years, or 

 once every eleven or twelve years, when esparsette 

 or lucern have been raised on it, that the quantity 

 of carbon thus given to the land corresponds to 

 only 5*8 per cent, of what is removed in the form of 

 herbs, straw, and grain, and further that the rain- 

 water received by a soil contains much more carbon 

 in the form of carbonic acid than these vegetable 

 constituents of the manure. 



