160 Royal Society : — 



anhydrous baryta were then allowed to ascend into the vapour- 

 volume, while the temperature was maintained constant. The mer- 

 cury began immediately to rise, becoming stationary again, when a 

 fraction of the vapour had disappeared, which amounted, the neces- 

 sary corrections being made, to half the original volume. 



"Notes of Researches on the Poly- Ammonias." — No. X. On Sul- 

 phamidobenzamine, a new base ; and some Remarks upon Ureas and 

 so-called Ureas. By A. W. Hofmann, LL.D., F.R.S. Received 

 July 24, 1860. 



Among the numerous compounds capable of the metamorphosis 

 involved in Zinin's beautiful reaction, the nitriles have hitherto 

 escaped the attention of chemists. This is the more remarkable, 

 since some of these bodies are easily converted into crystalline 

 nitro-compounds. 



When examining several of the diamines which I have lately 

 submitted to the Royal Society *, I was induced to study the trans- 

 formation which benzonitrile undergoes under the successive influ- 

 ence of nitric acid and reducing agents. 



Benzonitrile, when treated with a mixture of sulphuric and fuming 

 nitric acid, furnishes, as is well known, a solid nitro-substitute which 

 crystallizes from alcohol in beautiful white needles, containing 



C 7 H 4 N 2 2 =C 7 (H 4 , N0 2 ) Nf. 



In order to obtain this body, it is desirable to perform the opera- 

 tion with small quantities, and to cool the liquid carefully, otherwise 

 the formation of appreciable proportions of nitrobenzoic acid can 

 scarcely be avoided. 



The nitro-compound is readily attacked by an aqueous solution of 

 sulphide of ammonium ; sulphur is abundantly precipitated, and on 

 evaporating the liquid, a yellowish red oil is separated, which 

 gradually and imperfectly solidifies. This substance possesses the 

 characters of a weak base, dissolving with facility in acids, and being 

 again precipitated by the addition of ammonia and the alkalies. The 

 preparation in the state of purity, both of the base itself and of its 

 compounds, presents some difficulty. This circumstance has pre- 

 vented me from analysing the base. I have, however, examined one 

 of its products of decomposition, which leaves no doubt that nitro- 

 benzonitrile, under the influence of reducing agents, undergoes the 

 well-known transformation of nitro-compounds, and that the com- 

 position of the oily base is represented by the formula 



C 7 H C N 2 =C 7 H 4 (NH 2 )N. 



The oily base, when left in contact with sulphide of ammonium, 

 is gradually changed, a crystalline compound being formed, which is 

 easily soluble in alcohol and in ether, but difficultly soluble in water, 

 and which may be purified by several crystallizations from boiling 



* Phil. Mag. vol. xix. p. 232. + H = l ; = 16; C = 12, &c. 



