118 



Only a little more than one-half of the absorbed ammonia 

 had ttms heen recovered. 



In still another series of observations Yoelcker used ammo- 

 nium chloride, as Way had done, and upon the same series of 

 soils which he used in the cases first cited. His solution con- 

 tained 360 parts per million of ^H 3 , and 3500 grains of soil 

 were used to 14000 grains of solution, the determinations being 

 made after 3 days. 



In another series, but on the same soils, he used n solution of 

 ammonium sulphate which contained 288 parts per million of 

 ammonia. The ratio of soil to solution was 3500 to 14000. 

 The following are the results: 



Amounts of ammonia absorbed by five soils J'rom solution* of am- 

 monium chloride and ammonium sulphate. 



The sandy soil has, in each case, absorbed least ammonia, but 

 otherwise the results do not show much tendency to a marked 

 difference in absorptive effect ; but the question naturally arises 

 whether, in experiments conducted under these conditions, a ni- 

 trification of the ammonia salts may not have occurred, and 

 more with one soil than with another. 



OBSERVATIONS OF O. KUKLENBERG.* 



This investigator, in his absorptive studies, used a soil from 

 the Ida-Marienhutte Experiment Station, which, when di- 

 gested in water and in hot hydrochloric acid, gave the following 

 results : 



*Hoffman's Jahresbericht der Agrikultuv-Chemie. 1SG5, p. 15. 



