se of Sir Humphry Davy to the highest rank as a chemical
philosopher, was, after his appointment at the Royal Institution, rapid
and brilliant; and if he was previously aided by as few of the advantages
of fortune as any man living, he had then at his disposal whatever his
industry and talents chose to command. We have given but a hasty outline
of his labours; but it is possible that he may have left behind him much,
not yet made public, for which, science will be still further indebted to
him. His works, papers, and letters are numerous, and the greatest
portion of them are contained in the Transactions of the Royal Society.
One of the most popular and interesting of his recent papers is that on
the _Phenomena of Volcanoes_. This contains a series of investigations of
Vesuvius, made by the author during a residence at Naples in 1819-20, and
bearing upon a previous hypothesis, "that metals of the alkalies and
earth might exist in the interior of the globe, and on being exposed to
the action of air and water, give rise to volcanic fires, and to the
production of lavas, by the slow cooling of which basaltic and other
crystalline rocks might subsequently be formed." We have not space for
the details of these investigations, interesting as they would prove to
an unscientific reader; but we give an abstract of the result of Sir
Humphry's observations:

"The phenomena observed by the author afforded 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
atmospheric air may occasionally have access. The subterranean thunder
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 Solfattara 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 subterrane