CHAPTEE XLI 



ROTATION OF CEOPS 

 {Continued) 



WHEN soil is spoken of as worn out and need- 

 ing rest, the speaker uses a figure of speech 

 meaning that the soil has been exhausted by the 

 crops it has borne. The crops do indeed take from 

 the land a great quantity of substances necessary for 

 plant-life ; and when these substances are no longer 

 present in sufficient amount, the soil refuses to pro- 

 duce; it is exhausted. To restore its original fer- 

 tility would require a large outlay in fertilizer and 

 hence it is often more advantageous to accomplish 

 this object by one of the following methods. 



"Sometimes the land is allowed to lie fallow; that 

 is to say, it is left to itself without any care what- 

 ever for whole years. Weeds spring up freely, and 

 at the same time water, air, and frost act on the soil, 

 disintegrating and mellowing it and inducing the 

 formation of certain substances necessary to vege- 

 tation. The weeds are converted into mold, and 

 finally the land, rested and recuperated, is ready to 

 bear a new crop. Restoration by this process is 

 very slow, taking several years, and hence it is cus- 

 tomary to shorten the period of waiting by working 

 the soil and even manuring it, although it may not 



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