Journal of Agricultural Research 
Vol. V, No. 4 
156 
attractive forces for water, as has been abundantly proved. Further¬ 
more, if it is maintained that the attractive forces of the soil for water 
are satisfied as soon as the soil is merely damped, then why should the 
soil hold additional large amounts of water with such a great force that 
it is impossible to extract it with mechanical means? It seems reason¬ 
able, therefore, to believe that if the soil holds large amounts of water 
with a great force, it should attract or absorb it with a force of equal 
magnitude. 
MOVEMENT OF MOISTURE FROM A MOIST AND WARM COLUMN TO A 
DRY AND COLD COLUMN OF SOIL WITH AN AIR SPACE BETWEEN 
THE TWO COLUMNS 
In the preceding section the thermal translocation of water was con¬ 
sidered as occurring as water-film phenomena. There is still another 
way in which this thermal movement of moisture might take place: 
By vaporization and condensation of soil water from a point of high 
temperature to a point of low temperature. It is well known that water 
undergoes a transformation into the vapor state upon the application 
of heat, and the quantity of liquid vaporized increases with a rise in 
temperature. One of the remarkable characteristics of aqueous vapor 
is its sensitiveness to heat, changing from a gaseous to a liquid state, 
and vice versa, with very small variations in temperature. An excellent 
paradigm of this latter fact is the relative humidity of the air at different 
temperatures. 
Since the temperature gradient of the soil reverses itself during the 
night—that is, it increases with depth—it is believed that there is a rising 
of vapor or moist air from the warmer soil below to the colder soil above, 
where the moisture is condensed. As a manifest proof of this theory, 
the morning dew is cited. It is concluded, therefore, that a large part 
of the water movement in soils is due to this process. 
There appear to exist no direct experimental data as to whether or 
not there really is a translocation of moisture in soil at night, due to 
upward movement of the moist warm air and the condensation of its 
moisture at the cold soil above. Practically all of our present knowledge 
upon the subject consists of theoretical deductions from practical observa¬ 
tions. 
With the object of obtaining experimental evidence upon the subject 
the following investigation was performed. Into brass tubes 8 inches 
k>ng and 1 inches in diameter was placed moist soil at one end and dry 
soil at the other and the two columns separated by an air space. This 
air space was one-fourth of an inch in height and inches in diameter 
and was produced by placing between the two columns of soil a ring of 
cork, the two sides of which were closed with wire gauze that acted as 
supports of the two soils and prevented their particles from coming in 
contact. The tubes were then placed horizontally in the boxes shown 
