II. 



O?O 



CHAP TEE I. 



AS APPLIED TO THE SOIL. 

 THE SOIL, HOW FORMED, ETC., ETC. 



Agricultural Chemistry aims to explain all the 

 actions of earth, air, and water upon plants. It 

 refers to all their chemical relations, to the geology, 

 minerology and chemistry of soil. 



Soil is the loose surface material covering rocks, in 

 which the roots of plants are fixed, and is supposed 

 to be formed by their decay. Both are to be classed 

 by their origin, The origin of rocks refers not only 

 to the mode of their first formation, but to their 

 subsequent arrangement. The origin of all rocks, 

 geology teaches, is from the matter of the globe. 

 Referring rocks to their origin, they are divisible 

 into two classes, viz ; 



First Igneous, or those formed by fire, 

 Second Aqueous, or those formed by water, 

 This division relates both to the origin and 

 distribution. In their origin, rocks are truly 

 igneous, or from fire. In their distribution, they 



