CHARACTERISTICS OF SOILS 



27 



If the dew-drop could be caused to stand in space, and 

 freed from the pull of gravity, it would assume a perfectly 

 spherical form. If any part of the water of the dew-drop 

 could be removed, its size would be reduced, but its form 

 would at once become spherical again, because of the pull 



w 



FIG. 7. A mass of soil particles surrounded by capillary film, shown in 

 section. GG represents the ground line ; S, soil particles in section ; 

 W, water film ; A , the air spaces surrounded by capillary films which 

 in turn also surround the soil particles. 



of the surface molecules. As a matter of fact, the dew- 

 drop is not spherical as it hangs to the blade of grass. 

 It is symmetrical, and its free surfaces are curved ; the re- 

 moval or the addition of water does not change these facts. 

 Its new form will be symmetrical and its free surfaces 

 curved, all due to the pull of the surface molecules. 



When soil particles, or masses of soil particles, are 

 invested with capillary water, the surfaces of the water 



