On the Nature of Nitrogen, and the Theory of Nitrification. 27 



determined photometrically, although an accurate description is 

 not easily given. If a special colouring matter is to be deter- 

 mined, it is only necessary to ascertain, by one of the methods 

 described, the darkening which it experiences by glasses of defi- 

 nite colour. For a practical purpose, the special kind of glass 

 need not be determined. In the hand of the practical man they 

 are the known reagents for the colouring matter which he wishes 

 to test. 



III. On the Nature of Nitrogen, and the Theory of Nitrification. 

 By T. Sterry Hunt, F.R.S. 



To the Editors of the Philosophical Magazine and Journal. 



Gentlemen, Montreal, November 23, 1862. 



ENCLOSED I send a translation of a little paper of mine 

 from the Comptes Rendus, published in September last. It 

 relates particularly to two papers, one by myself, and one by 

 Schonbein, which have appeared in your journal, and I should 

 be much pleased to see it appear in your pages. 

 I remain, Gentlemen, 



Your most obedient Servant, 



T. Sterry Hunt. 



In 1848 I suggested that free nitrogen is the nitryl of nitrous 

 acid, NHO 4 , NH 3 — H 4 4 = NN, corresponding to the nitric 

 nitryl, NNO 2 , and to the phosphoric nitryl, PNO 2 (American 

 Journal of Science [2] v. 408 j vi. 172 ; viii. 375). It might then 

 be supposed that, like these two bodies, nitrogen should under 

 favourable conditions fix H 4 O 4 , and regenerate nitrous acid and 

 ammonia. In April 1861 I published a note in ( The Canadian 

 Journal ' of Toronto, in which it was said that the spontaneous 

 formation of these two bodies by the combination of atmospheric 

 nitrogen with water would serve to explain the production of 

 ammonia, so often remarked in the presence of air and reducing 

 agents, and also the formation of nitrates in the experiments of 

 Cloez, without the intervention of ammonia, and at the expense 

 of air and water in presence of alkaline matters [Comptes Rendus, 

 vol.lxi. p. 135). 



The simultaneous production of ozone and an acid of nitrogen 

 by the electric spark, and during the slow oxidation of phos- 

 phorus, may be explained by the power of active oxygen to 

 oxidize ammonia, thus setting free the acid of a small portion 

 of regenerated nitrite of ammonia, and even, in accordance with 



