July i6, 1917 Movement and Distribution of Moisture in Soil 



139 



The graph indicates that, where a soil is given sufficient time in contact 

 with a larger quantity of unsaturated soil, the initial percentage of 

 moisture has no effect on the final moisture content. 



It is quite probable that the small fluctuations shown in the figure 

 were produced by variations in the compactness of the soil in the tubes, 

 for it is very difficult to get the same amount of dry and wet soil in the 

 same space without compacting them differently. That this is the 

 explanation is supported by the fact that the tubes containing soil with 

 initial percentages of 4.83 and 10.31 contained, respectively, 703 and 603 

 gm. of dry soil. 



Percentage of moisfufe in soil 



.5 s r J ? "/ .'I '/ Y 'f 



^ZSZ^InifiaL moisture content 



FmaL moisture content. 



Fig. 



-Diagram showing the effect of the initial percentage of water on the final moisture content of soils 

 in contact with a wet loam having 30.45 per cent of water. 



Effect of Variation in Initial Percentage in Source of Supply 



Downward and upward movements as affected by varying initial per- 

 centages in the source of water supply were studied in this experiment. 

 Here 12 glass cylinders 14 inches tall and 2 inches in diameter were 

 filled with Greenville loam containing 2.12 per cent of water. Twelve 

 similar cylinders were filled in duplicate with Greenville loam having 

 15.87, 18.48, 20.24, 24.55, 27.74, and 29.9 per cent of moisture, respect- 

 ively. 



In one set the moist soil was placed above and in the other set beneath 

 the dry soil, in order to study the downward and upward movements. 

 Good contact was secured between the dry and wet soil before the joints 

 were sealed with paraffin. After six months (from Mar. 13 to Sept. 

 14, 1 91 6) the tubes were taken down and the moisture determined 

 in each 2 -inch section. The rise and descent of the water in the dried 



