dition of the Volcano subsequently to it." By Charles Daubenv, 

 F.R.S., F.G.S., and Professor of Chemistry in the University of 

 Oxford. 



It appears, from the information collected by the author, that for a 

 considerable time previously to the late eruption of Vesuvius, stones 

 and scoriae had been thrown up from the crater, and had accumulated 

 into two conical masses, the largest, of which was more than two hun- 

 dred feet in height. On the night of the 24th of August last, after 

 the flow of considerable currents of lava, a violent concussion took 

 place, followed by the disappearance of both these conical hillocks, 

 which, in the course of a single night, were apparently swallowed up 

 within the cavities of the mountain. Fresh currents of lava continued 

 to flow for several days subsequently, destroying about ISO houses, 

 spreading devastation over a large tract of country, and destroying all 

 the fish in the neighbouring ponds and lakes. After the 29th of August, 

 no further signs of internal commotion were manifested, with the ex- 

 ception of the disengagement of aqueous and aeriform vapours from the 

 crater, a phenomenon which, in a greater or less degree, isat all times 

 observable. The author descended twice into the interior of the crater, 

 which then presented a comparatively level surface ; its sides con- 

 sisting of strata of loose volcanic sand and rapilli, coated with saline 

 incrustations of common salt, coloured red and yellow by peroxide of 

 iron. The vapours which issued from various parts of the surface, 

 collected and condensed by means of an alembic, introduced into the 

 ground, were found to consist principally of steam and muriatic acid, 

 with only a slight trace of sulphureous or sulphuric acids. From a 

 trial with solution of barytes, the author concludes that carbonic acid 

 was also exhaled, but neither nitrogen nor sulphuretted hydrogen 

 appeared to form any part of the gas emitted. The steam issuing 

 from the lava contained both free muriatic acid and also muriate of 

 ammonia, which latter salt could not be detected in the gas from the 

 volcano itself. The author conceives that these volatile principles 

 are entangled in the lava, and are subsequently disengaged. 



March 26, 1835. 



WILLIAM THOMAS BRANDE, Esq., Vice-President, in the Chair. 



te On the Temperature of some Fishes of the Genus Thunnus." 

 By John Davy, M.D., F.R.S., Assistant Inspector of Army Hospitals. 



The author had occasion to observe, many years ago, that the Bonito 

 (Thynnus pelamys, Cuv.) had a temperature of 99° of Fahr. when the 

 surrounding medium was80° o, and that it, therefore, constituted an ex- 

 ception to the generally received rule that fishes are universally cold- 

 blooded. Having found that the gills of the common Thunny of the Medi- 

 terranean (Thynnus vulgaris, Cuv.) were supplied with nerves of un- 

 usual magnitude, that the heart of this latter fish was very powerful, 

 and that its muscles were of a dark red colour, he was led to conjec- 

 ture that it might, like the Bonito, be also warm-blooded ; and this 

 opinion is corroborated by the testimony of several intelligent fisher- 



