July It, 1917 Movement and Distribution of Moisture in Soil 1 43 



The greatest and least gains in moisture, as shown by the figure, took 

 place where the movement was vertically down and up, respectively. 



In the order of the quantity of water gained, the tubes were as follows : 

 Vertically down, 45° down, horizontal, 45° up, and vertically up. In 

 other words, gravity plays a very appreciable part in moisture move- 

 ment where the source of supply is a fairly large mass of comparatively 

 moist soil. 



EFFECT OF SOIL TYPE 



Where Moisture Moved Upward from Greenville Loam into Different 



Soil Types 



Greenville loam containing 28.36 per cent moisture was placed in bell 

 jars 6 inches in diameter and 10 inches deep. These jars were sealed 

 at the bottom. Through small openings in the top, glass tubes filled 

 with air-dry clay, Greenville loam, and sand were inserted into the 

 bell jars so the tubes were held vertically. The tops of the tubes and 

 the junction with the bell jars were carefully sealed. From time to 

 time during the experiment, which lasted from May 29 until October 

 18, 1 91 6, the rise of the moisture in the tubes was recorded. At the 

 end of the test the tubes were taken down and the moisture determined 

 for each 3-inch section. 



In figure 24 is shown the distribution of moisture by 3-inch sections 

 in each of the three soil types. The figure shows a decrease in moisture, 

 vdth an increase in distance from the point of contact with the moist soil. 

 This decrease was rather gradual in the loam and sand, but was more 

 abrupt in the clay. 



Coarse sand, such as was here used, drew into itself a very low per- 

 centage of water, while clay took sufficient to increase its own moisture 

 content to nearly that of the loam acting as the source of supply in 139 

 days. In the case of the loam, the moisture in the tube blended almost 

 without a break into that of the source of supply. 



The moisture moved farthest in the loam and least in the clay. This 

 shows that clay offers considerable resistance to the movement of mois- 

 ture, even when the source of water is a large mass of fairly moist loam. 



Where Moisture Moved Horizontally from Greenville Loam into Different 



Types of Soil 



In this case the Greenville loam, containing 30.45 per cent of water, to 

 act as source of moisture, was placed in a tub similar to those described 

 in previous experiments. Soils of the types shown in Table II, held in 

 24-inch brass tubes, were inserted horizontally into the tub, and the 

 whole apparatus was well sealed. 



The experiment was begun on May 24, and on September 1 1, 1916, the 

 moisture determination for each 2-inch section was made. 



