ABSORPTION OF SALTS BY SOILS. 



167 



If we compare the changes in nitric and phosphoric acid, and 

 silica, they appear as below: 



Here it is seen that everywhere more nitric acid has been 

 fixed during the longer interval or else and which is probably 

 the case more denitrification has occurred. More phosphoric 

 acid has also been 'fixed, except from the "A" solution, by the 

 soil under "good corn." In the case of silica it has been less 

 extensively fixed during the longer period, except in those two 

 cases where, during the 20-minute period, it was forced into 

 solution and where less potash was fixed, or the potash had been 

 actually forced into solution at the end of the 18 hour period. 



Comparing the changes which occurred during the two periods 

 in the case of the remaining three negative radicles SO 4 , HCO 3 

 and Cl, we have the results shown in the next table. 



