66 GEOLOGY OF AGRICULTURE. 



CHEMISTRY OF SOILS. 



100. One reason why rural employments arg not 

 regarded as the most desirable in which man can be 

 engaged, as they seem to have been by our Creator, 

 when He put our first parents into a garden, " to dress 

 it and to keep it," and when he ordained that three 

 fourths of the human race should live by agriculture, 

 is, that labor has been held to be the great and almost 

 the only requisite ; and physical labor hap been 

 esteemed less honorable than intellectual employment. 

 The truth is, that the employment which combines a 

 manly exercise of both the body and the mind is the 

 most favorable to long life and rational happiness; 

 and such precisely is that of the farmer. The Creator 

 never intended that the farmer's labors should be un- 

 reasonably severe, nor that he should thrive by mere 

 hand labor without the exercise of the higher facul- 

 ties ; and He has therefore made his employment such 

 as to require extensive and varied knowledge. One 

 important item of knowledge by which the labor of 

 farming may be diminished and its profits increased; 

 is that of the chemical composition of soils. 



101. Soils differ essentially in their chemical char- 

 acters. Some are nearlj^ or qu:"te destitute of several 

 ingredients necessary to fertility. Such are poor 

 soils. Good soils may contain them in very different 

 proportions. My present object is not to state these 

 proportions in any given soil, but rather to take a 

 general view of the causes of fertility as they exist in 

 the soil, and* in the rain and air which traverse it* 



