THE FOEMS OF SOIL-WATEE 183 



a rainfall ranging from twenty-two to forty-two inches. This 

 means that from one-third to one-half of the effective 

 rainfall was entirely lost as thermal water. The necessity of 

 checking such a loss becomes apparent, especially in regions 

 where rainfall is slight or drought periods are likely to occur. 

 As no country is free from one or the other of such con- 

 tingencies, the great prominence that methods of moisture 

 conservation hold in systems of soil management is under- 

 standable. While means of checking losses by leaching and 

 run-off are advocated, effective retardation of surface evapora- 

 tion is always emphasized. 



