60 BULLETIN 835, U. S. DEPARTMENT OF AGRICULTURE. 
zontally an average distance of 12 inches before it can moTe 
downward. 
The detailed measurements will not be given, but after 60 days the 
water in the gauge glass on the outside of the flume showed water 
up to a point within 11 inches of the surface of the water in the tank; 
that is, after 60 days that part of the tube below the point desig- 
nated " Gage E " in gauge glass was completely saturated. After 
the sixtieth day, the rate at which the water rose in the gauge 
glass was very slow, and upon the seventieth the experiment was 
terminated. 
This experiment, as did the previous ones cited, gave free water 
as a result of capillary action. 
Three additional experiments were run with the same tube, but 
containing soils of a different type. In each case the same result was 
obtained, except that they were terminated sooner and for that reason 
the water did not rise so high in the glass. 
Finally, it may be stated that in every flume, covered and open, 
that was inclined downward at an angle from 15° to 45° free water 
was developed when the experiment was run for a sufficient time. 
In only 3 or 1 instances out of the 20 or more flumes so inclined 
were the experiments terminated before free water was dripping 
from the lower ends of the flumes. 
Several tests were made of the amount of water taken up from 
the tanks and delivered again at the lower end of the flumes as free 
water. One of these tests will be given. 
The flume selected is No. 95, containing the lava soil from Idaho. 
This flume was covered, inclined downward from the horizontal at 
an angle of 30°, and was 15 feet in length. The records show that 
the flume commenced dripping water at the lower end on February' 
25, 1917. Commencing with March 1, the quantity of water lost 
from the tank by the wick was 18 liters. During this same period 
there was caught at the lower end of the flume 8.78 liters, or approxi- 
mately 50 per cent of the quantity taken from the tank. The water 
Avas caught in a can as it dripped from the flume. 
It has been suggested that a true siphon might have been formed 
as a result of " soil puddling " or other natural mechanical means. 
It did not occur in many cases and it is doubtful if it occurred at all. 
It is found, for instance, that with the use of clean, coarse build- 
ing sand, devoid of clay or other fine material, the same result is 
obtained. However, to test this point further, a system of ventila- 
tion within the wick was installed. 
Ventilating pads were made out of ordinary window-screen wire. 
From six to eight thicknesses of wire were rolled into a very small 
diameter and then flattened out. This made a pad of wire about 
