64 Generating Economic Cycles 



and the phase of the eight-year cycle is the mean of the 



go _i_ 92° 

 phases of the two cycles = 50° 30'. It will be 



seen from Figure 16 that the eight-year cycles in the cen- 

 tury of Sauerbeck's index numbers were approximately 

 synchronous with the corresponding cycles in the indi- 

 cated yield per acre of the British crops. The eight- 

 year cycle in the crops is proved to have persisted 

 throughout nearly the whole period of 159 years from 

 1760 to 1918 (the investigation of the American crops 

 was carried through 1918) or for an interval of twenty 

 cycles of eight years in length. This generating eight- 

 year cycle in the crops induced derived cycles of prices 

 which are reflected and verified in the century of Sauer- 

 beck index numbers of general wholesale prices. 



