[- 299 ] 



1 t! 



XUV. Proceedings of Learned Societies. 



ROYAL SOCIETY. 



[Continued from p. 78.] 



Dec. 14-, "/^"|N the effect of surrounding Media on Voltaic Tgni- 

 1848. V/ tion." By W. R. Grove, Esq., M.A., F.R.S. 



The author refers to some experiments of his published in the 

 Philosophical Magazine for December 184-5, and in the Bakerian 

 Lecture for 1847, relating to the difference of ignition generated in 

 a platinum wire heated by the voltaic current, when the wire is im- 

 mersed in atmospheres of different gases. In the present paper 

 these experiments are continued, the current being passed through 

 two platinum wires both in the same voltaic circuit, but immersed 

 in atmospheres of different gases. 



It appears from these experiments that the heat generated in the 

 wire is less in hydrogen and its compounds than in other gases ; 

 and that when the wires and their atmospheres of gas are immersed 

 in given quantities of water, the water surrounding the hydrogenous 

 gases is less heated than that surrounding those which contain no 

 hydrogen. 



Similar experiments, in which the wires ai'e immersed in different 

 liquids, are then given ; the heat developed appears not to depend 

 on the specific heat of either the gases or the liquids. 



The two series of experiments are brought into relation by one wire 

 being immersed in hydrogen and the other in water, by which it 

 appears that the cooling effect of the hydrogen nearly equals that of 

 water. 



Further experiments are then given, in order to ascertain, if possi- 

 ble, to what chemical or physical peculiarity these cooling effects are 

 due ; and from them it appears that they are not due to the specific 

 gravity, specific heat, or to any conducting power of the gases for 

 electricity ; and that they do not follow the same law as that by which 

 gases escape from minute apertures. They apparently depend upon 

 some molecular character of the gases, by which either the inter- 

 change of hot and cold particles is facilitated, or a superficial action 

 takes place, the surface of the hydrogenous gases presenting a more 

 ready escape to the heat, similarly to that which has been long ob- 

 served with regard to the different molecular constitutions of solid 

 bodies, such for instance as the more rapid radiation or absorption 

 of heat by black than by white surfaces, in the present case the 

 epipolie action being dependent on the surface of the aeriform me- 

 dium, and not on that of the solid substances. 



Jan. 11, 184'9. — " Contributions to the Physiology of the Alimen- 

 tary Canal." By W. Brinton, Esq., M.B. Communicated by R. 

 Bentley Todd, M.D., F.R.S. 



The paper consists of two parts, having a real relation to each 

 other, though apparently little connected. 



I. Qn the Movements of the Stomach. — The anatomy of its nius- 



