154 



Five times the weight of the drv soil of this solution was used 

 on each sample and it was caused to percolate through the sam- 

 ple three times in quick succession, the whole time required be- 

 ing from 30 to 45 minutes. The interval of contact is, therefore, 

 short, but the whole solution was forced to come three times in 

 contact with the soil by causing it to percolate under pressure 

 through a layer about three-sixteenths of an inch thick. 



As these soils had not ceased to yield salts to distilled water, 

 at the time they were used for this experiment, although they 

 had been 11 times washed, there has been made, from the 

 amounts of salts recovered by the last washing, an estimate of 

 what would probably have been recovered by another similar 

 cashing; and these amounts have been introduced into the 

 tables which follow and used in computing the effect of the soils 

 upon this solution. 



Ihe results found are given in the next table. 



