SOILS. 





water is retained, much to the injury of the surface soil. 

 These frequently occur upon the tops of hills, or upon 

 hillside slopes where the surface indications do not lead 

 one to suspect such conditions. Fig. i represents a 

 section of soil of this character. 



Fig. I. — Section showing Effect of Clay Subsoil upon Natural Drainage. 



The characteristics of soils as indicated above are 

 general, but are sufficient to point out what should be 

 looked for when their drainage is undertaken. These 

 general qualities are, however, dependent upon many 

 minute differences, such as mechanical fineness and 

 physical structure of the particles, the attraction which 

 their surface has for water films, the chemical compo- 

 sition of the component parts, and many other essential 

 particulars which have been observed and are still being 

 investigated by the soil physicist. 



Water of the Soil, 



Water which affects the soil exists in two conditions. 



Hydrostatic Water is visible to the eye and free to 

 obey the laws of gravity. It is water which is found 

 between the particles of the soil and passes off through 

 drains either natural or artificial. It is frequently 

 spoken of as drainage-water. 



Capillary Water is that which is held within the fine 

 pores of the soil by the surface attraction of its par- 



