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'I'lii 11 >) 111 ., 



The Physical Properties of Soils 



GENERAL INFORMATION AND 

 DIRECTIONS 



The laboratory instruction in soils is confined al- 

 most exclusively to a study of the physical properties 

 of soils and the relation of these properties to rational 

 methods of soil management. 



The relation of the soil to moisture being of first 

 importance, a great many of these experiments are 

 designed to show the influence of physical conditions 

 upon the movement and retention of moisture in the 

 soil. 



There are various ways of expressing the amount 

 of water present in a soil : ( i ) as per cent of dry 

 weight of the soil, (2) as per cent of wet weight, 

 (3) as pounds per cubic foot, and (4) as surface 

 inches. 



The water content is usually expressed either as per 

 cent of dry weight or as pounds per cubic foot. 



The degree of compactness of soils has a great in- 

 fluence upon their behavior, hence for all comparative 

 tests it is very necessary that all the soils be compacted 

 uniformly. For this purpose specially designed com- 

 pacting machines are used. 



Before beginning an experiment read carefully the 

 entire exercise and see that all the necessary apparatus 

 is at hand. 



