XX.] ON THE THEORY OF NITRIFICATION. 471 



tion in order to isolate the other. Certain reducing agents which 

 convert nitrous acid into ammonia may thus transform nitrogen (NN) 

 into 2NHs. In this way I explain the action of nascent hydrogen 

 in forming ammonia with atmospheric nitrogen in presence of oxidiz- 

 ing metals and alkalies An agent which, instead of attacking 



the nitrous acid, should destroy the newly formed ammonia, would 

 permit us to isolate the nitrous acid. Houzeau has shown that ac- 

 tive oxygen is such an agent, at once oxidizing ammonia with forma- 

 tion of nitrate (nitrite) of ammonia ; and thus when ozone is brought 

 in contact with moist air, both of the atoms of nitrogen in the nitryl 

 (NN,) appear in the oxidized state. From this view it follows that 

 the odor and many of the reactions ascribed to ozone are due to 

 nitrous acid, which is liberated by the decomposition of atmospheric 

 nitrogen in presence of water and nascent oxygen. We have thus 

 the key to a new theory of nitrification and to the experiments of 

 Cloez on the slow formation of a nitrite by the action of air ex- 

 empt from ammonia upon porous bodies moistened with alkaline 

 solutions." 



On September 15, 1862, I read before the French Academy of 

 Sciences a note on The Nature of Nitrogen and the Theory of Nitri- 

 fication, published in the Comptes Kendus of that date and trans- 

 lated in the Philosophical Magazine for January, 1863, in which I 

 repeated the points above given, and then proceeded to consider the 

 results announced by Schonbein in 1862. I said : " The formation of 

 nitrite of ammonia by the combination of the nitryl NN with 

 H 4 2 must necessarily be limited to very minute quantities by the 

 instability of this ammoniacal salt, which, as is well known, decom- 

 poses readily into nitrogen and water. In order, therefore, to pro- 

 duce any considerable quantity of a nitrite by this reaction, there is 

 required the presence of active oxygen, or of a fixed base to separate 

 the ammonia. The recent experiments of Schonbein have furnished 

 new evidences of the direct formation of a nitrite 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 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 



