CAPILLARY MOVEMENT OF SOIL MOISTURE. 



29 



FLUMES INCLINED DOWNWARD FROM THE HORIZONTAL. 



The flumes in which it was intended that gravity should assist the 

 capillary movement of moisture were inclined downward at various 

 angles from the horizontal. In all the flumes inclined in this way 

 the movement of the moisture and the amount of water used were 

 greater than for the horizontal flumes or the flumes inclined upward 

 from the horizontal. The extent to which water would move in the 

 inclined flumes where the inclination downward was 10 degrees or 

 more was, in most cases, beyond the limits of the equipment used. 

 Most of the experiments were carried to such an extent as to warrant 

 certain conclusions. The extent of this movement in the open flumes 

 appears to be limited not by the friction factors, but by the power of 

 the wick to supply moisture in sufficient quantity to take care of 

 the evaporation from the flume. That is, were evaporation elimi- 

 nated, the extent of movement in the flumes inclined downward at 

 angles greater than 30 degrees, except for the very heavy soils, would 

 be far beyond experimental limits. In the case of the very heavy soils, 

 as typified by the TYhittier type, there were indications that in the 

 less steeply inclined flumes friction played its part here as well as 

 in the horizontal flumes. 



In distribution of moisture there are found some differences be- 

 tween these flumes and either the vertical or the horizontal ; and, as 

 will be shown later free water was developed in the flumes inclined 

 downward. 



SOUS L'SED. 



Table 16 gives the numbers of the flumes and the soil contained in 

 each : 



Table 16. — Soils in flumes inclined downward. 



Nasal er 



of flume. 



Descrrotion. 



4 

 34 

 54 

 74 

 &4 

 204 



Decomposed granite soil from Riverside, Calif. 

 Decomposed granite and clay from Riverside, Calif. 

 Heavy clay soil from Whittfer, Calif. 

 Sand and gravel soil from Lplands, Calif. 

 Lava ash from Idaho. 

 Sandy soil from Idaho. 



Figure 4 gives the dates and measurements for -the movement 

 of moisture in flumes inclined at an angle of 30 degrees and open on 

 top to evaporation. The horizontal element is the time and the 

 vertical element the distance in inches. 



