296 AGRICULTURAL EXPERIMENT STATION. [Jan. 



results above given to encourage the belief that roasted 

 leather can have any definite money value as a manure." 



Wagner * has made an exhaustive study of the value of 

 different forms of nitrogen, having conducted 366 plat and 

 pot experiments. The experiments were carried on for 

 several successive years in a soil rich enough in lime to 

 favor nitrification, and every eflfort was made to have the 

 conditions equal in all cases. But a ver}^ brief resume can 

 be given at this time. One experiment was conducted for 

 three successive years upon small plats of soil. Summer 

 rye was planted the first year, summer wheat the second and 

 carrots the third year. Placing the value of the returns 

 from the nitrate of soda plats at 100, the other forms of 

 nitrogen had the following relative worth : — 



Experiments weve also conducted in pots with various 

 soils, but the results cannot be noticed here. 



In concluding his remarks relative to this subject "Wagner 

 sajs : — 



When I take all things into consideration, .... I think I 

 may present the following figures as an expression of the rela- 

 tive value of nitrogen in different forms of nitrogen-containing 

 material : — 



* Die Stickstoif-diingung, etc., page 255 



