MANURE. 



143 



geine, and of nitrates. The action of unferinented dung 

 needs no explanation after this exposition. The geine, the 

 salts, carbonic acid, and ammonia, must be formed among 

 the silicates and roots of plants on which they are to act. 



202. Having determined the mode of expressing the value 

 of manures, and fixing the standard of value, other manures 

 containing salts and geine, may now be compared with that, 

 and their value determined, by detailing their constituents. 



203. Horse-dung contains : 



100.00 



The food of the horse will of course affect these results, 

 and hence there is found a great discrepancy in the amount 

 of the elements, at different times. 



Girardin's analysis of horse-dung affords : 



Boussingault found that the following was the composi- 

 tion of the dung of a horse fed on hay and oats ; 



