SOIL WATER 



97 



to this constant water supply or water table, as it is 

 called, they stand a drought much better than plants 

 grown on undrained land where the water table has 

 not so uniform a depth. 



Experiment 63. Place small glass tubes of several different bores 

 in a dish of colored water. In which is the surface of the water 

 higher, in the tubes or 'in the dish? In which tubes is it the higher, 

 those of large or small bore? 



Experiment 54. Place two wide-mouth 4 oz. bottles side by side 

 and fill one partly full of water. Put a coarse piece of cloth, or better, 

 a lamp wick, into the water bottle and allow 

 the other end to hang over into the empty 

 bottle. Allow the bottles to stand thus for an 

 hour. What happens? The force that causes 

 the rising of water up small tubes, wicks and 

 crevices is called capillarity. 



Experiment 55. Tie pieces of cloth over 

 the ends of four lamp chimneys. Fill one of 

 the chimneys with coarse sand, another with 



Fig. 45. 



fine sand, another with clay, and the 

 fourth with a deep black loam. Stand 

 each chimney in a shallow pan of water. 

 Allow them to remain for a week, 

 keeping water in the pan all the time. 

 Note how high the water has risen in 

 the different chimneys at the end of 

 an hour ; two days ; a week. 



Fig. 46. 



It was found in Experiment 

 49 that each little particle of soil was surrounded 'by a 

 film of water, even though there was apparently no 

 water in the soil. This film will be replaced if removed 

 just as the water in the top of the wick (Experiment 54) 

 was replaced by water flowing up the wick. Roots get 

 a large part of their water by absorbing the water films 

 of the soil particles. 



If a region is well supplied with forests so that the rain 



