374 Limiiean Society. 



sulphate or muriate of potassa, with a minute portion Of oxide of 

 copper. In one instance, in which the crystals had a purplish tint, a 

 trace of muriate of cobalt was detected. From the observations 

 made by the author at different periods, he concludes that the dense 

 white smoke which rose in immense columns from the stream of 

 lava, and which reflected the morning and evening light of the 

 purest tints of red and orange, was produced by the sajts which 

 were sublimed with the steam. It presented a striking contrast to 

 the black smoke arising from the crater, which was loaded with 

 earthy particles, and which in the night was highly luminous at 

 the moment of the explosion. The phenomena observed by the 

 author afford a sufficient refutation of all the ancient hypotheses, in 

 which volcanic fires were ascribed to such chemical causes as the 

 combustion of mineral coal, or the action of sulphur upon iron ; 

 and are perfectly consistent with the supposition of their depending 

 upon the oxidation of the metals of the earths upon an extensive 

 scale, in immense subterranean cavities, to which water or atmo- 

 spheric air may occasionally have access. The subterranean thun- 

 der heard at great distances under Vesuvius, prior to an eruption, 

 indicates the vast extent of these cavities ; and the existence of a 

 subterranean communication between the Solfatarra and Vesuvius, 

 is established by the fact that whenever the latter is in an active 

 state, the former is comparatively tranquil. In confirmation of 

 these views, the author remarks, that almost all the volcanoes of 

 considerable magnitude in the old world, are in the vicinity of the 

 sea : and in those where the sea is more distant, as in the volcanoes 

 of South America, the water may be supplied from great subter- 

 ranean lakes ; for Humboldt states that some of them throw up 

 quantities of fish. The author acknowledges, however, that the 

 hypothesis of the nucleus of the globe being composed of matter 

 liquefied by heat, offers a still more simple solution of the phaeno- 

 mena of volcanic fires. 



LTNNiEAN SOCIETY. 



April 1. — Lord Stanley in the chair. 



His Lordship opened the meeting of the Society by adverting, 

 with much feeling, to the great loss which had been sustained by the 

 country and by the world, and more especially by the Society, in 

 the death of its illustrious and beloved President Sir James Edward 

 Smith, who from its first establishment, in which he had taken an 

 active part, had been called upon to preside over it by the annual and 

 unanimous votes of its members, and had greatly contributed to 

 place the Society in the distinguished rank which it had attained, by 

 his great talents, indefatigable industry, sound judgement, and en- 

 larged views as a naturalist ; — by the high estimation in which he had 

 long been held by men of science all over the world ; by the excel- 

 lence of those valuable and accurate works in which he had done so 

 much to promote and improve the study of natural history ; and espe- 

 cially by the qualities of his heart, mind, and temper, for which his 

 memory would long be revered by those who had enjoyed the happi- 

 ness of his friendship. — He could not forbear expressing what he 



felt 



