28 FIRST PRINCIPLES OF AGRICULTURE. 



prevent a too rapid leaching or evaporation of water ; 

 lime^ to assist in the decay of vegetable matter ; and 

 humus, to retain the best amount of moisture, and to 

 furnish material for the various chemical processes con- 

 tinually going on in good soils. 



These conditions are rare, and seldom occur in nature, 

 though it is in the power of man to produce them: still, 

 perfect soils are not to be had without a great deal of 

 labor and care ; and frequently it is more important for 

 the farmer to adapt himself to his soil, and make it 

 produce the best which, from its natural character, it is 

 best capable of doing, than to attempt to change its 

 character. He should not attempt to raise wheat when 

 the soil is peculiarly fitted to grow early vegetables or 

 fruits, nor to grow early vegetables on soils only adapted 

 for the grasses. 



