146 



Journal of Agricultural Research 



Vol. V. No. 4 



of moisture. On referring to the data in Table II it will be seen 

 that the maximum thermal water transference at the amplitude of 

 20° C. is 0.90 per cent for light sandy loam, 0.93 for heavy sandy 

 loam, 1. 19 for silt loam, 1.07 for Clyde silt loam, and 0.99 for clay; at 

 the temperature amplitude of 40° it is 2.88 per cent for light sandy loam, 

 3.02 for heavy sandy loam, 3.68 for silt loam, 3.27 for Clyde silt loam, 

 and 3.29 for clay. It should be noted that the percentage of thermal 



Fig. 3. — Curve showing the movement of moisture from a warm to a cold column of soil of uniform moisture 



content. 



motion of water increases more than proportionally with temperature. 

 The temperature of 40°, for instance, is only twice as great as 20°, while 

 the percentage of moisture moved is three times greater in the former 

 case than in the latter. The water content of the various soils at which 

 the maximum thermal translocation occurs is 7.50 per cent for light 

 sandy loam, 9.08 for heavy sandy loam, 14.21 for silt loam, 18.80 for 

 Clyde silt loam, and 19.29 for clay. 



