228 ORIGIN OF THE NITRATES. 



product is a polymeric substance, discovered by Thenard. 

 Nitrogen and acetylene, moreover, do not form hydrocyanic 

 acid under the influence of the silent discharge, a result which 

 contrasts with the abundant formation of this compound under 

 the influence of the spark. However, the condensed product 

 formed by acetylene modified in presence of nitrogen, when 

 subsequently destroyed by heat, liberates towards the close 

 some traces of ammonia. 



17. Nitrogen and carbohydrates. The following are various 

 experiments relative to the absorption of nitrogen by the action 

 of the silent discharge at high tension, which are calculated to 

 show that this absorption really takes place, when operating 

 with the principal constituents of vegetable tissues, either with 

 pure nitrogen or in presence of oxygen, that is, by bringing 

 atmospheric air into action. 



White filter paper (cellulose or ligneous principle) slightly 

 moistened and submitted to the influence of the silent discharge, 

 in presence of pure nitrogen absorbs a very marked quantity of 

 it in the space of eight to ten hours. It is sufficient to heat the 

 paper strongly afterwards with soda-lime, to liberate from it a 

 great quantity of ammonia. The original paper did not appre- 

 ciably yield any under the same conditions. Ammonia, besides, 

 is only produced towards a dull red heat by the destruction of 

 a particular and fixed nitrogenous compound, as with the 

 hydrocarbons. 



18. The presence of oxygen does not prevent this absorption 

 of nitrogen. The following experiment shows this. The glass 

 tubes through which the electric influence is exerted having 

 been covered with a thin coat of a syrup-like solution of 

 dextrine (a few decigrammes in all), a certain volume of 

 atmospheric air was introduced into them over mercury. 



After having made the silent discharge act for about eight 

 hours, an absorption of 2'9 per cent, of nitrogen and 7'0 of 

 oxygen in 100 volumes of the original air was observed. It 

 will be seen that the absorption of the oxygen was not total 

 under these conditions. As a check the organic matter remain- 

 ing on the surface of the tubes was collected and heated with 

 soda-lime, it liberated ammonia in great abundance and only 

 towards a dull red heat, which completes the demonstration. 

 For the rest, it was not found that free ammonia, nitric or 

 nitrous acids were formed in any appreciable amount, at least 

 under these conditions. 



19. The principal phenomenon is therefore the production of 

 a complex nitrogenous compound by the direct union of free 

 nitrogen with the carbohydrate experimented upon, a reaction 

 perfectly comparable to those which must be produced in 

 nature, by the contact of vegetable matter with the electrified 

 atmospheric air. 



