Contents. 



Preface 1 



I. The stale of the drought question 3 



II. The method of investigation 13 



III. The laws of the circulation of water 16 



IV. The root -system of plants and their role in the water regime 



of the soil 24 



V. The yearly water regime in the root-inhabited layers of the soil 28 



The periodically or upper humid layer 29 



The permanent humid soil layer or lower humid layer . 31 



The intermediate dry layer 31 



The permanent humid layer 33 



VI. The appearances of drought 35 



VII. Measures for contending against drought 43 



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