298 AMMONIA AND NITKIC ACID. 



the form of ammonia, does not, therefore, exist as such 

 in the earth. 



Even if the experiments above described do not 

 afford any proof that all the nitrogen in the ground is 

 in the form of ammonia (a portion, besides, is in most 

 cases present as nitric acid), there is, on the other hand, 

 no proof furnished to the contrary. 



Strictly speaking, the discussion of the point in 

 question does not depend on this proof ; for it is suffi- 

 cient to show here, that the comportment of the soil 

 i with respect to the amount of nitrogen in it is exactly 

 the same as that of farm-yard manure. Only a small 

 portion of the nitrogen in farm-yard manure, is sepa- 

 rable by distillation with alkalies ; the much larger por- 

 tion being obtained only by complete decomposition of 

 the substances. 



According to Yoelker's analysis, 800 cwt. of fresh 

 farm-yard manure contained 



1854, November. 1855, April. 



Ibs. Ibs. 



Nitrogen .................................... 514 712 



Ammonia " * ............ 97-6 H- t 



If we compare with this the amount of separable 

 ammonia and the total nitrogen in the soil at Schleiss- 

 heim and Bogenhausen, we have 



Schleissheim. Bogenhausen. 



Ibs. Ibs. 



800 cwt. of arable soil contain nitrogen ...... 321'6 267'2 



Present as separable ammonia .................. 101'6 68'0 



It is manifest, that when two soils, not particularly 

 rich in nitrogen, contain just as much ammonia as an 

 equal weight of farm-yard manure, if we ascribe the 

 effect of the latter merely to the amount of ammonia 

 which it contains, then the unfruitfulness of the field 

 at Schleissheim is entirely inexplicable. 



We assume that the entire quantity of nitrogen in 

 farm-yard manure has a definite share in its operation ; 

 and as the nitrogenous matters in the arable soil are 

 originally identical with the substances which form the 



