CAPILLARY ACTION 103 



to the redistribution of the water coating the particles, and 

 the movement then becomes very slow. 



Another reason for the slow movement of water in natural 

 soils lies in the fact that the water has to be drawn from 

 moist soil and not from free water. A fine passage tries 

 to fill itself at the expense of a wider one, a thin film grows 

 at the cost of a thicker one, and the result in each case 

 is merely the difference in their respective powers. This 

 is one chief reason of the great falling off in the rate of rise 

 as the column of soil lengthens; we have already seen that 

 an alluvial soil (p. 99) took forty-two days in accomplishing 

 the 47th inch. It is evident that when rain and percolation 

 have ceased, the movement of water from a wetter to a drier 

 part of the soil must be greatly hindered by the reluctance 

 of the wetter soil to part with its water. Even when, as 

 at Wisconsin, the water level in the subsoil is fairly near 

 the surface, the rise of water in the soil is by no means 

 free from this hindrance, the so-called water level beiug 

 merely the surface of a mass of saturated soil. 



An excellent example of the slow movement of water in 

 a dry natural soil is afforded by another of King's experiments 

 (Wisconsin jth Rep., 143). After the dry summer of 1889 

 a soil was sampled on Oct. 28, to a depth of 5 ft., and the 

 percentage of water at different depths determined. A portion 

 of the ground was then effectually protected from rain and 

 snow and left in this condition till April 14 in the following 

 year, when the soil was again sampled as before, and the water 

 present determined. For results obtained see Table XVII. 



The covered soil had apparently gained no water from 

 below during the winter months, but had on the contrary 

 actually lost some water by evaporation. The soil open to 



