CAPILLARY MOVEMENT OF SOIL MOISTURE. 
Table 44. — Movement of moisture downward from ivet soil. 
65 
Days. 
Riverside soil, 
initial percentage. 
Idaho lava soil, 
initial percentage. 
Whittier soil, 
initial percentage. 
20 per 
cent. 
15 per 
cent. 
14 per. 
cent. 
20 per 
cent. 
25 per 
cent. 
41 per 
cent. 
30 per 
cent. 
1 
2 
3 
4 
5 
7 
8 
9 
13 
16 
22 
27 
31 
36 
41 
43 
49 
71 
76 
Inches. 
4.50 
Inches. 
4.00 
5.75 
6.37 
7.00 
Inches. 
0.75 
Inches. 
2.00 
Inches. 
3.00 
5.25 
Inches. 
Inches. 
7.50 
4.75 
5.00 
1.75 
9.00 
11.75 
8.50 

4.00 8.00 
14.00 
15. 75 
17.25 
9.50 
10.75 
11.25 
12.00 
12.00 
4.50 | S.50 
15.25 
21.50 
16.25 
17.25 
2.25 
2.00 
14.25 
15.00 
11.50 
25. 50 
16.25 
12.75 

21.50 
22.25 
1 
COMPARISON OF CAPILLARY MOVEMENT OF MOISTURE UPWARD AND DOWNWARD FROM 
A BODY OF WET SOIL. 
A series of experiments were outlined to determine the relative 
extent and rate of movement of moisture upward and downward 
from a body of soil containing a known percentage of moisture. In 
this experiment a section in the middle of the box was filled with 
wet soil and air-dried soil was packed at both ends. The box was 
then placed vertically. In this experiment the capillary movement 
occurred with gravity downward and in opposition to gravity. There 
was a secondary factor which must be considered, and that is the 
gradual concentration o-f moisture in a wet soil at the lower end of a 
vertical column due to gravity. That is, while the middle part of the 
flume was filled with a soil containing a uniform percentage of 
moisture it would be found after a few days, depending upon the de- 
gree of wetness of the soil, that there was a greater percentage of 
moisture near the bottom than near the top of the wet soil column. 
The more nearly the soil was wetted to the point of capillary satura- 
tion the greater would be the difference in percentage of moisture 
near the bottom and near the top. 
Table 45 shows the upward and downward movement of moisture 
in two of the boxes. 
The box containing the Idaho soil was 8 feet long and the middle 
32 inches was packed with wet soil. There was an equal length of air- 
dry soil at each end. 
The box containing the Riverside soil was 8 feet long and the mid- 
dle 4 feet was packed with wet soil. 
147697°— 20— Bull. 835 5 
