84 [May 8, 



4. The heart, at least the heart of the frog, has two distinct sets 

 of nervous fibres, those of the pneumogastric and those from the 

 ganglion- cells, which are both distributed to the muscles. The vagus 

 therefore acts directly on the muscular fibres of the organ, and the 

 well-known experiment of "Weber can scarcely be explained through 

 a supposed action of the vagus on the ganglia. On the other hand, 

 the ganglia and their fibres are also motorial organs of the heart, 

 and alone act when it is separated from the body. 



May 8, 1862. 

 Major-General SABINE, President, in the Chair. 



Heinrich Wilhelm Dove, of Berlin, elected a Foreign Member in 

 1850, and Henri Victor Regnault, of Paris, elected a Foreign Member 

 in 1852, were admitted into the Society. 



The following communication was read : 



" Appendix to the Account of the Earthquake- Wave Experi- 

 ments made at Holyhead." By ROBERT MALLET, Esq., 

 C.E., F.R.S. Received March 27, 1862. 



(Abstract.) 



This communication contributes the sequel of the author's " Re- 

 port on Earthquake-Wave Experiments" (made at Holyhead), 

 as published in part 3 of the * Philosophical Transactions ' for 

 1861. At the conclusion of that paper the author expressed his 

 hope of being able soon to lay before the Royal Society some experi- 

 ments for the determination of the modulus of elasticity of perfectly 

 solid portions of both the slate and the quartz rock formation 

 through which his wave-transit experiments had been made at Holy- 

 head, with a view to throw light upon the relations between the 

 theoretic velocity of transmission (if the rocks were all solid and 

 homogeneous) and the actual velocity as determined by experiment. 



He has now determined the elastic modulus for both rocks, and 

 for each rock in two directions, viz. parallel to and transverse to its 

 lamination ; and he has extended his determinations to specimens of 



