"168 



In these three cases the negative radicles have gone into solu- 

 lution in increasing amounts in all cases with the longer contact 

 of the solutions with the soil. It is also to be observed that the 

 changes have been, throughout, greatest with the "B" solution 

 where the nitric acid went in, in combination with lime, as was 

 the case also with nitric and phosphoric acids, only these de- 

 creased rather than increased in the solution. 



Attention should be called herfc, as was done in a previous 

 section,-p. 54, to a well marked indication of chlorine, previously 

 absorbed by the soil and not readily recovered by single wash- 

 ings in distilled water, being forced into solution under the con- 

 ditions to which the soils were here subjected. Indications of 

 absorbed chlorine have also been pointed out in Bulletin "B," in 

 connection with observations made in the preliminary study and 

 development of the methods. An alternate hypothesis, in con- 

 nection with this series of data, would be that the decomposition 

 of organic matter attendant upon the denitrincation which oc- 

 curred in these cases, may have liberated both combined chlorine 

 and perhaps SO 4 , from difficultly soluble compounds, thereby in- 

 creasing the amounts in the solutions after contact with the soils. 



