CAPILLARY ACTION 143 
feet or more is depleted. This is shown by the 
following analyses of dry-farm soil in early spring 
and midsummer. No attempt was made to conserve 
the moisture in the soil: — 
+ 1st 2d 3d 4th | 5th | 6th | 7th | 8th 
Per cent of water in | foot | foot | foot | foot | foot | foot | foot | foot | Average 
‘ Karly Spring . . 20.84] 20.06] 19.62 13,28 18.70] 14.29] 14.48] 13.83] 17.51 
Midsummer . . 8.83] 8.87) 11.03 aa 11.27] 11.03] 8.95) 9.47 9.88 
In this case water had undoubtedly passed by 
capillary movement from the depth of eight feet 
to a point near the surface where direct evaporation 
could occur. As explained in the last chapter, 
water which is held as a film around the soil particles 
is called capillary water; and it is in the capillary 
form that water may be stored in dry-farm soils. 
Moreover, it is the capillary soil-moisture alone which 
is of real value in crop production. This capillary 
water tends to distribute itself uniformly throughout 
the soil, in accordance with the prevailing conditions 
and forces. If no water’is removed from the soil, 
in course of time the distribution of the soil-water 
will be such that the thickness of the film at any point 
in the soil mass is a direct resultant of the various 
forces- acting at that particular point. There will 
then be no appreciable movement of the soil-mois- 
ture. Such a condition is approximated in late 
winter or early spring before planting begins. The 
