TEMPERATURE OF SOILS. 



TABLE CONCLUDED. 



233 



It will be seen from the foregoing observations, tliat the greatest difference between the 

 temperature of the earth and the air occurs in the spring. The earth acquires the proper 

 temperature for the coming vegetation rather slowly, in consequence of the evaporation 

 required in order to dry it sufficiently. In tlie autumn, in September and October, it seems 

 to have acquired a stock of caloric sufficient to expend for some time without exliaustion, 

 while at the same time it operates favorably in sustaining the proper temperature for the 

 [Agricultural Report.] 30 



