CAPILLARY MOVEMENT OF SOIL MOISTURE. 



59 



after the moisture had reached the lower end of the flume inclined 

 downward at an angle of 15° free water commenced dripping from 

 the lower end. The water continued to drip from the ends of all 

 three of these flumes for at least two weeks, or until the flumes were 

 dismantled. It must be kept in mind that this water was raised 

 from the tank a vertical distance of 4 inches by capillarity and 

 against gravity. It was then transmitted down the flumes by means 

 of the same force and in a direction with gravity. The moisture 

 left the soil column at the lower end of the flume as free water, drop- 

 ping to the ground. At no point in the entire length of the soil 

 column, with the possible exception of the extreme lower end of the 

 flume, was the percentage of moisture in the soil as great as that of 

 capillary saturation, as measured by the 

 general methods for determining this 

 percentage. This, then, is in effect 

 transferring water from a body of free 

 water by capillarity and delivering it 



X 



again as free water 



MS. 

 GageE 



A 



To supplement the results from the 

 flumes and to test the further possibility 

 of creating a capillary siphon, a special 

 piece of apparatus shown in figure 10 

 was set up, 



A-B in. figure 10 is a galvanized-iron 

 tube 7 by 7 inches in area and made in 

 the shape shown. This box is water- 

 tight and air-tight, except along the top 

 X-B, at the bottom of the short arm at 

 C, and at a point D at the bottom of the 

 long arm. This tube stands vertical 

 and rests on A. The top along the line 

 X-B is open to the air. The lower end 

 of the short arm at C has soldered over it 

 a fine-meshed wire gauze. D is a f-inch ell soldered into the lower 

 end of the long arm ; the top of the ell is fitted with a water-gauge 

 connection. Into the top of this ell is fitted a gauge glass X-D, on the 

 outside of the tank or tube. The tube is packed with soil as indicated 

 and the soil is exposed to the air along the line X-B. The short 

 arm of the tube extends down into a tank of water represented by 

 water line in tank. 



It is observed from figure 10 that the high-water line in the 

 tank is 8 inches below the bottom of the horizontal part of the tube. 

 This 8 inches is then the distance the water must be raised from the 

 tank before it can move horizontally. It must then move hori- 



Fig. 10. — The soil column as a 

 capillary siphon. 



