82 



Generating Economic Cycles 



of pines in Arizona, and the international crop cycles 

 to which we have so frequently referred. The graph 

 is given in Figure 23. 



Monthly Rainfall in the Dakotas. m*y*nd junc 



ANNUAL Rainfall in the Ohio Valley 



Figure 23. Cycles in the rainfall of the Dakotas, of the Ohio Valley, and of Illinois. 

 Dakota cycle: y = 3.09 + 0.45 sin (^|.^°< + 84° 39'), origin at 1882; 

 Ohio cycle: y = 41.2 + 4.13 sin (1|A°< + 310° 41'), origin at 1839; 

 Illinois cycle: y = 38.5 + 3.05 sin (MiL°< + 241° 52'), origin at 1870. 



At the time of the publication of the essay Economic 

 Cycles, 1914, Illinois was regarded as our leading 

 cereal-producing state, ranking first in the production 

 of corn and second in the production of oats. Rainfall 

 records for many stations in that state w^re available 



