204 
Journal of Agricultural Research 
Vol. VIII, No. 6 
Table IV .—Percentage of water that fails to freeze and the percentage of water content at 
which solidification refuses to take place 
Name of soil. 
Percentage 
of water at 
which Solidi¬ 
fication 
refuses to 
take place. 
Percentage 
of water - 
that fails to 
freeze. 
Sand. 
Sandy loam. 
5- 60 
3 - 52 
10. 50 
17 . 30 
Silt loam. 
Heavy silt loam. 
16. 00 
t? cn 
Heavy silt loam. 
15. ou 
It becomes at once evident from an examination of the foregoing re¬ 
sults that the percentage of water at which solidification can not be 
induced to start and the percentage of water which fails to freeze are 
quite close in all the different types of soil. 
RELATION BETWEEN THE AMOUNT OF WATER THAT FAILS TO FREEZE AND 
THE THERMAL CRITICAL MOISTURE CONTENT 
In investigating the effect of temperature on some of the most im¬ 
portant physical processes in soils, the effect of temperature on the 
movement of water vapor and capillary moisture was also studied (3). 
It was found that when one-half of a column of soil of uniform moisture 
content was maintained at 20° and 40° C. and the other half at o° for 
eight hours, the percentage of water moved from the wann to the cold 
soil increased in all the different types of soil with the rise in moisture con¬ 
tent until a certain water content was reached and then it decreased with 
further increase in the moisture content. The results then plotted into 
a parabola. The percentage of moisture at which the maximum thermal 
translocation of water occurred was different in the various classes of 
soil, but the percentage of the maximum thermal translocation of water 
was about the same for all classes for any one of the temperature ampli¬ 
tudes employed. The percentage of moisture at which this maximum 
translocation occurred was designated as “thermal critical moisture 
content.” 
It is now of great interest to state that this thermal critical moisture 
content is practically the same as the percentage of water which refuses 
to freeze in the corresponding soils—that is to say, the percentage of 
water in the soil at which the maximum thermal translocation occurs is 
practically the same as the percentage of water which refuses to freeze. 
This significant correlation was tested in about 10 different soils, and in 
almost every case the relation was exceedingly close, the variation not 
exceeding more than 3 per cent water content in any soil. 
