CONSERVATION OF SOIL MOISTURE 



individual soil grain is more or less sur- 

 rounded by a film of moisture, as will be 

 seen hereafter, it is evident that, other 

 things being equal, the largest aggregate 

 area of earth grains AviU retain the most 

 water per cubic foot. Let us make this 

 plain by a simple sum. Suppose that a 

 cubic foot of marbles one inch in diam- 

 eter has a total surface of 27.7 square 

 feet. Now, for the sake of argument, 

 reduce these marbles to one thousandth 

 of an inch in diameter, and you will find 

 that the total area per cubic foot is in- 

 creased to 27,700 square feet. From this 

 httle problem it is clear that the total 

 amount of water capable of being ab- 

 sorbed by a soil which is cloddy and 

 lumpy must be very small in comparison 

 with that in a finely divided state, and not 

 only is the absorbing power of the soil 

 much less, but its capacity for holding 

 moisture is likewise greatly diminished. 

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