226 . Royal Society : — 



final result in every case might be a fourth difference instead of 

 a number formed by fourth differences. At any rate, I conceive 

 that the object is within the reach of mechanical contrivance. 



If this could be done, I really believe that a very iinportant 

 benefit would be conferred on computers. 



Of the other operations, the fourth would be effected by a very 

 simple difference-engine ; possibly also the third might be con- 

 veniently done by mechanism, though it is sufficiently simple in 

 numerical calculation. 



I am. Gentlemen, 



Your obedient Servant, 



G. B. Airy. 



XXXI. Proceedings of Learned Societies, 



ROYAL SOCIETY. 

 [Continued from p. 149.] 



Jan. 17, 1856.— Prof. William Allen Miller, M.D., V.P., in the 



Chair. 

 r| "^HE following communication was read : — 

 X " On some of the Metamorphoses of Naphthalamine." By 

 A. W. Hofmann, Ph.D., F.R.S. &c. 



The great facility with which some of the nitro-hydrocarbons can 

 be reduced by means of iron and acetic acid — the modification of 

 Zinin's process, lately proposed by M. Bechamp — enables us to 

 obtain the corresponding bases in larger quantity, and to examine 

 their derivatives more minutely. 



One of the bases, for the preparation of which this process is par- 

 ticularly applicable, is naphthalidine, or as it is more appropriately 

 called, naphthalamine. Mr. "William H. Perkin is engaged in exa- 

 mining the deportment of this substance with chloride of cyanogen, 

 and the following is a summary of the results he has at present 

 obtained. 



Fused naphthalamine, when submitted to the action of chloride of 

 cyanogen, absorbs this gas with great avidity, and is gradually con- 

 verted into a dark resinous mass. This is the hydrochlorate of a 

 new base, which has received the name of menaphthalamine, in con- 

 sequence of the analogy of its origin with that of melaniline, derived 

 by a similar process from aniline, 



Menaphthalamine is separated from the hydrochlorate by potassa, 

 washed and repeatedly recrystallized from alcohol. It contains 



and is formed according to the equation 



2C,o Hp N + Cj, NCI = C,, H,7 N3 HCl. 



Naphthala- Chloride of Hydrochlorate of 

 mine. cyanogen, menaphthalamine, 



Mr. Perkin has verified this formula of menaphthalamine by the 



