148 



It will be clear from this table that some notable changes have 

 occurred during the longer interval of digestion. They may be 

 best .seen by averaging the duplicate determinations and com- 

 bining these, as given in the next table. 



Mean amounts of salts absorbed by the Hagerstown Loam from a 

 salt solution during 24. and 12 hours. 



The data of this table make it appear that these soils have in- 

 creased their content of phosphoric acid, by absorption from the 

 solution during 72 hours, adding to what they already had 

 nearly 140 parts per million for all four feet; but at the same 

 time they appear to have lost from 8 to 37 parts of silica. 



Sulphuric acid, contrary to the observations of the earlier in- 

 vestigators cited, has been absorbed in very large amounts by all 

 four feet at the end of 72 hours, although, at the end of 24 

 hours, the duplicate determinations on the second foot showed a 

 solution from that soil of 44 and 42 parts per million. 



The large apparent absorption of nitric acid by the soil of the 

 surface foot may be due to denitrification. 



The first, second and third feet lost lime, as would be expected 

 from earlier observations, until the end of 24 hours and, except 

 the third foot, to the end of 72 hours. The fourth foot, how- 

 ever, absorbed an increasing amount to the end. 



