CAPILLARY MOVEMENT OF SOIL MOISTURE. 
39 
from underground water sources by capillary action of the soil. It 
must be kept in mind, however, that in the case of the flumes evapo- 
ration and capillarity are acting at the same time. 
Table 
28. — Distribution of mois- 
ture in flume 96. 
DISTRIBUTION OF MOISITTRE. 
The distribution of moisture in the flumes inclined upward at an 
angle of 15° does not differ materially from the distribution in 
the vertical flumes. In Table 28 is 
given the distribution of moisture in 
flume 96 at various times. It will be 
noticed that in this table, as in that 
for the vertical flumes, there is rather 
a uniform constant quantity of mois- 
ture near the lower end and then a 
gradually decreasing, amount to- 
ward the top of the flume. The rates 
of decrease, however, are not com- 
parable as far as the figures in this 
table and those for the other flumes 
indicate. 
In the open flumes there are several factors which account for a 
lack of uniformity in the distribution of moisture other than the 
mere fact of elevation above the surface of the water. The rate of 
evaporation is different for different points of the flume clue to dif- 
ferences in moisture content of the soil (18). The concentration at 
the surface of the soluble salts of the soil, which will be different at 
different points throughout the flume, would cause some difference in 
the moisture content due to lessening evaporation. 
Distance. 
Percentage of w 
ater. 
Top5 
inches. 
Bottom 
5 inches. 
Average. 
Inches. 
Per cent. 
Per cent. 
Per cent. 
28 
28.32 
29.66 
28.99 
40 
28.56 
27.89 
28.82 
52 
26.70 
26.26 
26.48 
64 
24.83 
24.87 
24.85 
76 
25.06 
24.20 
24.63 
88 
21.71 
21.96 
21.83 
94 
20.58 
20.95 
20.77 
100 
17.25 
17.73 
17.49 
Table 29. — N u m oer of 
flume and angle of in- 
clination. 
EFFECT OF GRAVITY ON THE MOVE- 
MENT OF SOIL MOISTURE BY CAPIL- 
LARITY. 
No. of 
flume. 
Angle of incli- 
nation. 
34 
32 
31 
39 
42 
43 
30° downward. 
15° downward. 
Horizontal. 
15° upward. 
45° upward. 
Vertical. 
As stated in this report, the plan was to 
have capillarity act in the direction of grav- 
ity, in a direction opposed to gravity, and in 
a horizontal direction in which gravity was 
eliminated as far as possible. To give an idea 
of the influence of gravity in the movement 
of soil moisture by capillarity there are given 
below data on a complete set of flumes containing the heavy Riverside 
soil. "While the other soils show considerable variation, these varia- 
tions are almost entirely in degree and it is not thought that the ad- 
dition of these data to this report would be of any material benefit. 
Table 29 gives a list of the flumes in the set under consideration 
and their angles relative to the horizontal. 
