EXPERIMENT STATION BULLETINS. 



G41 



More recently colovimetric metliods have been employed. Fine sand 

 was treated with normal potassium hydrate, a two-inch layer placed in 

 the bottom of test tubes one inch in diameter and two inches in length. 

 The tubes were then filled, with a portion of the sand that had previously 

 been moistened with phenolpthalein indicator, permitted to become dry 

 and then moistened with distilled water. In this manner the rate of 

 diffusion was readily determined. Typical examples of the results ob- 

 tained are given in table 2. 



The above data show that the rate of diffusion although slow increases 

 with the water content of the sand and decreases with an increase in 

 distance from the deposit. Attention should be called to the possibilities 

 for development of the method to be used as a laboratory experiment in 

 soil physics. 



The translocation of salts as affected by film water movement has also 

 received consideration. In these investigations galvanized iron c<»ntaiii- 

 ers four inches in diameter were employed. Salt treated layers six inches 

 in thickness were placed at different depths from the surface in order 

 to throw some light upon the relation between surface and subsoils in 

 this respect. In addition the salt was uniformly distributed through- 

 out the soil column. 



TABLE 3. — MOVEMENT OF SALT THROTKiH SILT LOAISI 12 INCHES FUONr ST'UFACK 



DURATION OF EXPERIMENT 32 DAYS. 



Treated Soil. 



M inch . . . 



1 inch . . . 



6 inches . 

 15 inches. 

 24 inches . 



LTnti{e.\ted Soil. 



.578 

 .055 

 .053 

 .058 

 .070 



