CAPILLAKY MOVEMENT OF SOIL MOISTURE. . 6 
The work as planned and carried out embodied a study of the rate 
and extent of capillary movement of moisture in columns of various 
types of soil, where capillarity was assisted by gravity, where it 
acted against gravity, and where gravity as a factor was eliminated. 
The columns in which gravity was to assist capillarity were inclined 
downward at various angles from the horizontal; the columns in 
which gravity was to act against the force of capillarity were inclined 
upward at various angles from the horizontal; and the columns in 
which the effect of gravity was to be eliminated as far as possible were 
set horizontal. 
Inasmuch as evaporation is one of the factors that controls the 
extent and rate of movement of soil moisture by capillarity, it was 
decided to run each set of experiments in duplicate, except that one 
column was to be covered on all sides and evaporation reduced to a 
minimum, while the other column was to be uncovered and exposed 
on one side to the air. 
It was essential to the plan of the experiments that the probability 
of free water as such entering the columns be reduced to a minimum 
and yet have sufficient water enter the flumes to give something with 
which to work. It was desired to have a high initial percentage of 
capillary water, and at the same time eliminate free water. To accom- 
plish this end it was decided to have a vertical lift from the surface 
of the water in the tank to the bottom of the container of the soil 
column proper of from 3 to 4 inches. After several preliminary tests 
a vertical lift of 4 inches was adopted and all columns except the ver- 
tical ones (unless otherwise stated) have a vertical " lift" of 4 inches 
from the surface of the water in the tanks to any change in direction 
of the column. That part of the soil column from the surface of the 
water to the point of change in direction has been termed the " wick v 
in the discussion which follows. 
Air-tight joints were maintained and no water escaped from the 
tanks except by the wick and no moisture from the columns except 
by evaporation. To guard against the formation of a true siphon 
within the soil column an air space was maintained upon at least one 
side of the soil column throughout its entire length, in the columns 
inclined downward. 
All water added to the tanks after the initial filling was measured 
and recorded. At specified intervals the position of the outward ex- 
tent of the wet area of soil was measured and these measurements 
recorded. 
The experiments in which a moist soil was the source of moisture 
rather than a body of free water differ but little from those described, 
except that evaporation was eliminated in all cases. 
The soil boxes were partially filled with a soil containing a known 
percentage of moisture, greater than the wilting percentage, and the 
