74: GEOLOGY OF AGRICULTUKE. 



of the fifteen elements enumerated in Table I., and 

 yet that none of these elements exist in soils in their 

 simple uncombined state ; also, that nearly all the com- 

 pounds in Table I. either constitute a portion of soils, 

 or are in some way so connected with soils, as to act a 

 part in the process of vegetation. These binary com- 

 pounds, however, very few of them, exist in soils, as 

 binary compounds. They are further combined with 

 each other, forming salts (see Table II.). It must be 

 recollected that the acids combine with the bases 

 (Table III.) and form salts, whose names end in ate^ 

 the name in each case expressing the compounds of 

 which the salt is formed. If you were to put sulphuric 

 acid and quick-lime into a soil together, they would 

 not remain sulphuric acid and quick-lime. The acid 

 would immediately combine with the lime, and sul- 

 phate of lime (gypsum) would be the result. So there 

 are constant changes going on in the soil, and the 

 higher the cultivation, the more rapid and numerous 

 the changes. To control these changes, to arrest such 

 as are unfavorable, and to hasten those which are 

 favorable to the growing of crops, is the great object 

 of scientific agriculture. When this is better under- 

 stood, the farmer can increase his crops without in- 

 creasing the expense in an equal proportion, and, con- 

 sequently, he can increase his profits. 



122. Soils consist of two parts — the organic and the 

 inorganic. By the inorganic we are to understand the 

 mineral part, that which remains after a- portion of 

 soil has been heated to redness ; by the organic, that 

 which burns away. The organic part is animal and 



