The Mechanism of Cycles 119 



respective general cyclical movements. The present 

 question concerns the relation of the cyclical move- 

 ments themselves, after their respective secular trends 

 have been eliminated. 



It will be recalled that the general cyclical movements 

 were obtained by a process of smoothing the actual 

 series of the indices of prices and of yield per acre, the 

 process consisting in the formation of a progressive 

 mean of the indices for three consecutive years. These 

 smoothed series, which are given in Tables III and VI 

 of the Appendix to this chapter, form the data of the 

 present investigation. 



The method of the investigation is presented in Fig- 

 ures 25, 26, 27. In the first of these three Figures, the 

 general cyclical movements of prices and of yield per 

 acre are described according to the data of Tables III 

 and VI. The graphs bring out clearly the rhythmical 

 motions of both prices and yield and a comparison 

 of the curves suggests that the price curve is a lagging 

 reproduction of the yield curve. But before the amount 

 of the lag and the degree of correlation between the 

 cycles can be computed, the secular trends in the two 

 series of values must be eliminated. From Figure 25 it 

 is apparent that the price cycles move upon a falling 

 secular trend while the yield cycles move upon a rising 

 secular trend. If it is assumed as a first approximation 

 that these secular trends are both linear, the equation to 

 the trend for prices is y = — .3702x + 122.01, and to the 

 trend for the yield per acre, y = .1844:r+98.57, the ori- 

 gin, in the former case, being at 1875 and, in the latter, 



