EXPERIMENT STATION BULLETINS. 717 



duced in the soil and tlins influence the freezing point depression. There 

 were in all IG soils employed. These soils represent several different types 

 and practically all the various classes. In order to afford a basis of 

 comparison these soils were taken from the same samples as the soils in 

 table 22. To ascertain the influence of high temperature upon the rate 

 and solubility of soils, therefore, the results in table 22 must be taken 

 as basis for comparison. The data obtained are shown in table 24. The 

 number of each soil corresponds to the similar soil in table 22. 



TABLE 24.— RATE AND EXTENT OF SOLUBILITY OF NATURAL SOILS IN DISTILLED 

 WATER WHEN THE RATIO OF SOIL TO WATER IS ABOUT 1 TO .7 AND MIXTURE 

 MAINTAINED AT THE TEMPERATURE OF 53° C. FIGURES REPRESENT FREEZING 

 POINT DEPRESSION. 



From a careful comparison of the data in the above table with that 

 in table 22 it becomes at once evident that the temperature of 53 °C 

 influenced quite appreciably both the rate and extent of solubility, and 

 especially of certain soils. It is readily seen that the rate was con- 

 siderably hastened and the extent quite ai)preciably increased, on prac^ 

 tically all the soils. 



The process of solubility continues for a long time even 60 days, but 

 the major portion of the material goes into solution the first three or 

 four days. Even at the end of the fiirst day the solubility product of 

 many soils is rather large. The final total amount of material that went 

 into solution varies tremendously in the various soils. It ranges from 

 a depression of .010° in sand (No. 17) to .011° in Cecil clay (Xo. 4) to 

 .013° in Okley fine sandy loam (No. 26) to .038° in silt loam (No. 14) to 



