44 SCIENTIFIC REPORTS OF THE AGRICULTURAL RESEARCH 



As this is a preliminary experiment, and is now being 

 repeated under more stringent conditions, it is only neces- 

 sary to point out that the increment due to the green manure 

 tends to increase as the cropping due to nitrogen alone 

 increases, thus giving some confirmation to the conclu- 

 sions deduced from previous investigations. 



A series of experimental pots have been laid down with 

 the object of determining the comparative values to be 

 ascribed to the direct and indirect action of green manures. 



X. Miscellaneous. 



At my request, my First Assistant repeated the labora- 

 tory experiments on which a portion of Memoir, Vol. II, 

 No. 3, Botanical Series, " Note on a toxic substance 

 excreted by the roots of plants," was based, using an 

 artificial nutrient solution in place of the well water used 

 by the author. Briefly, the method of experiment was to 

 grow a large number of wheat, arhar (Cajanus indicus) 

 and gram seedlings in the solution for a certain period of 

 time, and then to allow the solution to evaporate spon- 

 taneously to one-third of its original bulk. A " blank " 

 concentrated solution was also prepared by the evaporation 

 of a solution in which no seedlings had been grown. It 

 was found that the seedlings grown in this concentrated 

 solution thrive much better than those grown in the 

 " blank," thus offering no support to the theory of toxic 

 excretion. 



Samples of tobacco from experimental plots receiving 

 different manurial treatment were examined for total ash, 

 "potash, chlorine, amido-nitrogen and proteid content, and it 

 was found that, with the exception of chlorine, these values 

 bore no relation to the treatment received. Tested for their 

 burning value by Toth's method it was observed that tobacco 

 manured with saltpetre burnt well but quickly, that with 

 superphosphate treatment was much inferior. A combina- 

 tion of these manures produced a tobacco which burnt 

 fairly well and not too quickly. 



