180 OF MANURE. 



ing the proportion of carbon, nitrogen, and inorganic 

 matter contained in faeces, in comparison with the 

 food taken.* (Playfair.) 



Carbon 4524 



Hydrogen ....•*.. 6-88 



Nitrogen (average) 4* 00 



Oxygen 3030 



Ashes 13-58 



The inorganic matter contained in the excrements 

 analyzed is nearly two per cent, less than that found 

 by Berzelius ; but the proportion always varies, ac- 

 cording to the nature of the food. 



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 sainfoin or lucern has 

 been raised on it, that the quantity of carbon thus 

 given to the land corresponds to only 6-8 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 car- 

 bonic acid than these vegetable constituents of the 

 manure. 



The peculiar action then, of the solid excrements 

 is limited to their inorganic constituents, which thus 

 restore to a soil that which is removed in the form 

 of corn, roots, or grain. When we manure land with 

 the dung of the cow or sheep, we supply it with 

 silicate of potash and some salts of phosphoric acid. 

 In human fseces we give it the phosphates of lime 

 and magnesia; and in those of the horse, phosphate 



* The details of the analysis are as follows: — 2-356 grammes left 

 0320 gramme ashes after incineration ; these consisted of the phosphate 

 of lime and magnesia. 0352 gramme yielded, on combustion with 

 oxide of copper^ 576 gram, carbonic acid, and 0-218 gram, water. 

 (L. P.) 



