CAPILLARY WATER 



211 



The evaporation from the lysimeters or drain gages at Koth- 

 anisted, England, from bare soil at depths of 20 inches and 60 

 inches, shows an excess of 0.11 of an inch per annum for the deeper 

 soil mass as an average for 34 years. This represents the water 

 brought to the surface from the 40 inches of subsoil of the deeper 

 gage, and amounts to only 12 tons per acre per annum, or not suffi- 

 cient to grow more than one-half bushel of wheat. This indicates 

 tbat a very small amount cf water is brought from a depth greater 

 than 20 inches by capillarity in a clay loam soil. 



Rainfall and Evajmralion at Rothamsted, England, n Average fm 34 Yearn, 



1871 to 1.904 



Results for maximum and minimum rainfall 



Maximum (1903) 

 Minimum (1898). 



38.69 

 20.49 



15.21 

 13.17 



15.09 

 12.59 



14.46 

 12. SO 



The Capillary Pull of Soils. It is quite important to be able 

 to measure this capillary force for different soils. A method for 

 doing this lias been devised by Lynde and Dupre. It consists of 

 placing the soil in a funnel on a cotton cloth filter that is con- 

 nected with a water column by means of a wick. The water column 

 rests upon a column of mercury, the lower end of which is in a 

 vessel of mercury. As the water evaporates from the surface of the 

 soil the water in the tube rises and with it the mercury. The height 

 of the mercury represents the pull. The capillary lift is quite large 



