Geological Society. 77 



several other isomeric bodies under the influence of nitrous acid. 

 There are two basic compounds, 



C 6 (H 6 N0 2 )N, 

 known ; the one is the alphaphenylamine of Hofmann and Muspratt, 

 the other the betaphenylamine observed by Arppe. When submitted 

 to the action of nitrous acid, these two isomeric bodies yield two 

 perfectly different nitrogen-substituted derivatives. The substance 

 obtained from alphaphenylamine (the base formed by the reduction 

 of dinitrobenzol) has been already mentioned in one of my previous 

 notes, the body derived from betaphenylamine is still under exami- 

 nation. 



The action of nitrous acid proves that there are also two bromphe- 

 nylamines similar to the two nitrophenylamines. The original brom- 

 phenylamine discovered by Hofmann, and which is formed by the di- 

 stillation of bromisatine with hydrated potash, yields with nitrous 

 acid a compound, 



C 12 H 9 Br 2 N 3 = N'" I N 2 , 



H J 

 crystallizing in beautiful golden-yellow needles, insoluble in water, 

 and difficultly soluble in alcohol and ether. The bromphenylamine, 

 on the other hand, which was lately prepared by Mills * from acetyl- 

 bromphenylamide, exhibits with nitrous acid a perfectly different 

 deportment, being transformed into a yellow scarcely crystalline com- 

 pound, easily soluble in alcohol and ether, but insoluble in water. I 

 have not as yet analysed this compound ; its formation, however, 

 and its properties render it probable that it will be found to be iso- 

 meric with the product of decomposition previously mentioned. I am 

 engaged in a more minute examination of this compound, which I 

 hope may assist in explaining the cause of the still enigmatical iso- 

 merism exhibited by the derivatives of phenylamine. 



I have already repeatedly called attention to the different atomicity 

 exhibited by nitrogen under different conditions. In the derivatives 

 of amidobenzoic and of anthranilic acids, it can be proved that 

 1 equiv. of nitrogen replaces 1 equiv. of hydrogen; while in the 

 derivatives of phenylamine, the nitrogen is present with the value 

 of three molecules of hydrogen. 



GEOLOGICAL SOCIETY. 

 [Continued from vol. xxi. p. 539.] 

 April 24, 1861. — Leonard Horner, Esq., President, in the Chair. 

 The following communications were read : — 

 1. "On the ' Symon Fault' in the Coalbrook Dale Coal-field." 

 By Marcus W. T. Scott, Esq., F.G.S. 



This communication was based on observations made during many 

 years on a section through a part of the Shropshire Coal-field in 

 * See the previous abstract. 



