360 Royal Society : — 



getic. The extremely small expansion which takes place in 

 carbon by heat is another argument against that view of the 

 Trevelyan experiment. The other experiment to which I refer, 

 is, that bismuth (and perhaps other metals) are not merely inac- 

 tive as vibrators with any electric power which I have used, but 

 the passage of electricity through them appears to have a 

 quelling power which brings the rocker to instantaneous rest ; 

 yet bismuth permits a far freer passage of electricity than car- 

 bon : in one experiment I found that sixteen times as much was 

 conducted. Something analogous was formerly observed by me 

 in connexion with heat applied to bismuth. I am now attempt- 

 ing to investigate the subject further by experiment. 

 January 3, 1859. 



LX. Proceedings of Learned Societies, 



ROYAL SOCIETY. 



[Continued from p. 305.] 



November 25, 18.58.— W. R. Grove, Esq., V.P., in the Chair. 



THE following communications were read : — 

 "Researches on the Phosphorus-Bases." — No. III. Phos- 

 phoretted Ureas. By A. W. Hofmann, Ph.D., F.R.S. 



The existence in the nitrogen-series of a well-defined group of 

 diamines of the formula 



^;In„ 



rendered it probable that the continued study of the phosphorus-, 

 arsenic-, and antimony-bases would lead to the discovery of the cor- 

 responding terms, , . . . 



B, [ P,, £^ [ As,, and B^ [ Sb,, 



cj ' c:\ - cij 



which might be designated as diphosphines, diarsines, and distibines ; 

 and the further prosecution of this line of thought very naturally 

 suggested the idea of searching for a group of intermediate compounds 

 containing simultaneously nitrogen and phosphorus, nitrogen and 

 arsenic, phosphorus and arsenic, &c., compounds expressed by the 



formulae . . . ^ . -, 



A] A] A] 



5, InP; ^, InAs; bAfAs,&c., 



cj cj c:j 



which might be termed phosphamines, arsamines, pbospharsines, &c. 



Among the several processes likely to furnish this result, none ap- 

 peared more promising than the reaction between a monamine and a 

 mouophospbine of opposite chemical characters. 



In the conception of this idea, I have studied the deportment of 



