120 BULLETIN NO. 139 



foot of uncovered soil surface. Water was added from time to 

 time so that there was always a movement toward the evaporat- 

 ing end. 



TABLE 1. SOLUBLE SALTS IN EACH SECTION OF SOIL 

 THROUGH WHICH TEN LITERS OF WATER HAD 

 PASSED HORIZONTALLY. 



The experiment was begun August 23, 1912, and continued 

 till February 10, 1913. During this period 10 liters of tap water 

 passed through the soil in each tank. There were seven tanks 

 in all, each containing a different soil treatment. 



At the end of the experiment the soil was removed from 

 the tanks in foot sections, and the samples numbered ; number 

 one being given to the section where the water was added, and 

 number six to the section where the evaporation occurred. 



The total soluble salts were determined by adding 500 c. c. 

 of distilled water to 100 grams of soil, stirring for three min- 

 utes, then letting settle twenty minutes, and filtering through 

 a Chamberlain-Pasteur porcelain filter; 50 c. c. of the filtrate 

 was evaporated to dryness and the weight of the residue de- 

 termined. The results are given in Table 1 and Figure 1. 



It will be noted that the salts moved with the current of 

 water and accumulated at the end where evaporation took place 

 from the surface. In general, the salts increased in the soil 

 from the end where the water was added to the other end. The 

 increase was not in every case regular. The figures bring out 

 clearly the fact that the soluble salts in the soil move horizon- 

 tally with the current of soil moisture. 



