WAI IK IN SOILS 



93 



vious stratum is far below the surface the soil is said 

 to be deep. 



then, is found in the soil in two forms; in 

 the soil near the surface it ordinarily exists as film 

 moisture. In the lower soil it is found as free water, 

 which, rising in the soil, forms the film 

 moisture above.' -eg 



EXPERIMENT 



To Uluttrate how free water viae* in soil and becomes B | 

 Aim moisture, the following simple experiment is useful : t =• 



Take an ordinary glass tube of any convenient size % • 

 and stop up one aid with a plug of loosely fitting cotton. £«• 

 Then fill the tube with dry soil Dip the end with the "2 § 

 cotton plug in water just deep enough to cover the end S.J 

 of the tube. Water rises through the dry soil until it is H » 

 all thoroughly moistened. Fig. 15 illustrates this ex- J* 

 pcriiiunt. 2. 



Questions |s 



1. When a marble is dipped into water what 

 happens to it? 2. When water is poured on a 

 pile of stones with what does each stone become 

 surrounded? 3. When rain water soaks into f 

 the soil with what is each little soil particle 

 surrounded? 4. What is the moisture surrounding each 

 soil particle called? 5. Which absorbs the more moisture, 

 a pile of fine earth or a pile of stones, and which dries out 

 the more rapidly? 6. When water which soaks through the 

 soil reaches a hard layer of soil or rock through which it 

 cannot pass what happens to it? 7. What Is the water that 

 fills the soil just above the impervious stratum called? 

 8. The dividing line between the soil filled with free water 

 and that containing film moisture Is called what? 9. Why 

 does the level of a water table change? 10. How deep does 

 a well have to go in the soil before it reaches water? 

 11. How does the free water supply film moisture to the 

 soil above? 12. In wet weather how does the water table 

 behave? 



