Chemistry and Physics. 



, the possibil 



nitrE 



'"On September 15, 1862, I read before the French Academy 

 of Sciences a note on The Nature of Nitrogen, and the Theory of 

 Nitrification, published in the Comptes Rendus of that date, and 

 translated in the Philosophical Magazine for January, 1863, in 

 which I repeated the points above given, and then proceeded to 

 consider the results announced bjr Schonbein in 1862. I said, 

 "The formation of nitrite of ammonia by the combination of nitryl 

 NN with H^ O 2 must necessarily be limited to very minute quantities 

 by the instability of this ammoniacal salt which, as is well known, 

 decomposes readily into nitrogen and water. In order, therefore, 

 to produce any considerable quantity of a nitrite by this reaction, 

 there is required the presence of active oxygen, or of 

 to separate the ammonia. The recent experiments ' 

 have furnished new evidences of the direct formation of a 

 at the expense of the nitrogen of the atmosphere. According to 

 him, when sheets of paper moistened with a feeble solution of an 

 alkali, or an alkaline carbonate, are exposed to the air, especially 

 in the presence of a watery vapor, and at a temperature of 50° or 

 60° C, the alkaline base soon fixes a sufficient quantity of nitrous 

 acid to give the characteristic reactions. Appreciable traces of 

 nitrite are, according to Schonbein, obtained in this way, even 

 without the intervention of an alkali. He, moreover, found that 

 distilled water, mixed with a little potash or sulphuric acid, and 

 evaporated slowly at a temperature of about 50° C. in the open 

 air, fixes in one ease a small portion of ammonia, and in the other 

 a little nitrous acid. Traces of a nitrite are also formed in pure 

 water under similar conditions. Schonbein explains all these re- 

 sults by the combination of nitrogen with the elements of the 

 water, producing at the same time ammonia and nitrous acid. As 

 he has well remarked, this reaction serves to explain the absorp- 

 tion of nitrogen by vegetation, and through the oxidation of 

 nitrite, the formation of nitrates in nature. By these elegant 

 experiments he has confirmed, in a remarkable manner, my theory 

 of nitrification, and of the double nature of free nitrogen. It is, 

 however, evident that since the publication of my note of March, 

 1861, above referred to, we cannot say with SchSnbein that the 

 generation of nitrite of ammonia from nitrogen and water is ' a 

 most wonderful and wholly unexpected thing.' " 

 . " It is, however, unfortunate for Dr. Hunt's theoretical anticipa- 

 tions that no sooner did experimentalists begin to purify the air 

 that they used in repeating Schonbein's experiments, than the 

 production of nitrite of ammonia suddenly stopped. The experi- 

 ments of Bohlig and, more recently, of Carius, show that neither 

 during the evaporation of water in air, nor during the condensa- 

 tion of its vapor, does a trace of nitrite of ammonia manifest itself. 

 The experiments of Carius are especiallv decisive on the point, as 

 they were both numerous and most carefully performed. The 



