AGRICULTURAL PRACTICE AND CLIMATIC CYCLES. 



269 



In any event, it seems clear that the attack upon this vital problem from 

 both the intensive and extensive approach will disclose new facts and leads 

 and will bring nearer the actual utilization of cycle predictions in crop pro- 

 ductions. 



1870 178 1886 1894 1902 1910 



Fig. 20. Cycles of rainfall in the Ohio valley, , and in Illinois,. 



aai8 



After Moore. 



T I I I I I I r 



i870 1876 1882 1888 18M 1900 1906 3912 1918 



Fig. 21. Cydes in the yield of corn and in the rainfall of its critical period 

 of growth. After Moore. 



