3G2 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



Nitrification by Electrical Discharges. 



The oxidation of free nitrogen by electrical discharges has 

 lonor since been established. Whether enough of the nitro- 



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gen of the air is thus oxidized and then absorbed by plants 

 to be of much consequence is very doubtful. But late re- 

 searches by Berthelot have revealed a very noteworthy man- 

 ner in which nitrogen may be absorbed by organic com- 

 pounds, under the influence of the silent electrical discharge. 

 A large number of compounds were thus found to absorb 

 nitrogen, both that existing in the pure state and that in the 

 air, producing compounds all of which evolved ammonia on 

 beino- heated, either alone or with soda-lime. Berthelot suit- 



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gests that similar processes may take place in nature, and 

 that consequently plants may be able to assimilate nitrogen 

 directly from the air. This last assumption is, however, op- 

 posed to the results of the best previous investigation upon 

 the subject, which indicate that the free nitrogen of the air 

 is not assimilated by plants (Comptes Rendus, lxxxii., 1283, 

 and Ixxxiii., 677). 



Is the Nitrogen Combined under the Influence of the Soil a Source 

 cf the Supply Assimilated by Plants 1 



Does not the soil cither free nitrogen from the air and in- 



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duce it, in some way or otner, to enter into combinations in 

 which it can be used by the plant ? This is a question which, 

 though not yet decided, seems, in the light of recent experi- 

 menting, to approach an affirmative answer. In the resume 

 in the Record for 1870, in discussing the probability of the 

 direct assimilation of atmospheric nitrogen by plants, the re- 

 mark was made that " it would seem more probable that the 

 absorption of free nitrogen by humus and by soils containing 

 humus, which Simon and Truchot claim to have observed, 

 might be induced in the manner described by Berthelot." 

 The experiments of the past year bring no new evidence of 

 importance against this view. On the other hand, it seems 

 more and more probable that the ways in which crops get 

 their supplies of nitrogen are to be sought in the varying 

 capacities of their roots for feeding upon the nitrogen con- 

 tained in various forms in the soil. Dr. Gilbert concludes 

 the remarkable address to which we have been referring 



