118 



Dans le cas de la detente du maximum d'effet, et pour la meme 

 pression de 6 atm., les resultats sont les suivants, 

 avec les espaces libres effec- 



avec les espaces libres nuls T m = 26*35 ch. 



II. " On the Action of Nitrous Acid on Aniline." By A. 

 MATTHIESSEN, Ph.D. Communicated by Professor STOKES, 

 Sec. R.S. Received January 12, 1858. 



On repeating the experiments of Hunt* and Hofmannf, on the 

 action of nitrous acid on aniline, I found that the reaction does not 

 take place exactly as these chemists state ; Hunt gives the reaction 

 as 



H 



Hofmann says that phenylic alcohol is not formed, but nitrophe- 

 nassic acid, when binoxide of nitrogen is led into a diluted solution 

 of the nitrate : 

 C, 



1 HI 



12 H 5 l 



This reaction, although correct in the end result, omits the inter- 

 mediate stage, which is 



H 

 H 



and then NH 3 + NO 3 =N 2 - 



On account of the free nitric acid, the phenylic alcohol is always 

 converted into nitrophenassic acid. The ammonia was determined 

 as platinum salt, and two experiments gave 43*9 and 44' 1 per cent, 

 of platinum ; the theoretical quantity required is 44*2 per cent. 



It appears, therefore, when nitrous acid acts on aniline, that in 

 the first part of the reaction it causes only a substitution, and after- 

 wards, the ammonia being attacked by it, gives off nitrogen and 

 water. 



* Sill. Am. Journ. (2) viii. 372. f Chem. Soc. Quart. Journ. iii. 231. 



