CONTENTS 



CHAPTER I 

 Introduction 1 



CHAPTER II 



CYCLES OF RAINFALL 



The Use of Fourier's Theorem 6 



Periodogram of Rainfall 14 



The Equation to the Rainfall Curve 21 



Rainfall in the Corn Belt 26 



CHAPTER III 



RAINFALL AND THE CROPS 



The Secular Trend in the Yield of the Crops 35 



Critical Periods of Growth 41 



Cycles in the Yield of the Representative Crops and the 



Corresponding Cycles of Rainfall '. . . 44 



Cycles in the Index of Crop Fluctuations and in the Corre- 

 sponding Index of Mean Effective Rainfall 49 



CHAPTER IV 



THE LAW OF DEMAND 



The Theory of Demand 62 



Statistical Laws of Demand 66 



The Prediction of Prices 77 



Elasticity of Demand 82 



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