228 



MANGANESE IN THE LEGUMINOS^ 



In the nitrification trials, commenced in 1897 and con- 

 tinued by M. Boname in 1898 and 1899, it has been demon- 

 strated that the manganese combines with the nitric acid 

 formed whenever bases, such as Hme or ammonia, are absent. 



It may be said, without contradiction, that the nitric acid 

 formed during nitrification does combine with the manganese, 

 in spite of the soil not being devoid of lime, and this would 

 prove that the manganese is easily attacked. 



The experiments we have made on the solubility of the 

 manganese in our soils in very weak acid solutions have 

 shown this solubility to be fairly great. 



Take 100 grm. of dried soil and 500 c.c. of nitric acid 

 solution at 2 c.c. per 1,000. 



After dissolving for twenty-four hours, with frecjuent 

 shakings during the first ten hours, we have : — 



In 100 Parts of Soil. 



Total 

 manganese 



0-200 

 0-218 

 0-189 

 0-233 . 

 O-I03 

 0-265 

 0-239 . 

 0'II2 

 0-387 . 



o-i 18 

 o-ioS 



0-322 



Aqueous solutions were substituted for weak acids, under 

 the same conditions, i.e., 100 grm. of soil + 500 c.c. of 

 distilled water, dissolved for twenty-four hours. 



The quantities found were too small to be measured, but 

 the solutions were sufficiently coloured to demonstrate the 

 presence of manganese. 



In his annual report for 1908 M. Boname has given a 

 series of figures showing the proportions of manganese in 

 the ash of different plants. We reproduce these herewith, 

 at the same time establishing the relationship between the 



