384, 443, 500-512.
According to the different phases of chemical science, bitumen, pyrites, the
moist admixture of finely-pulverized sulphur and iron, pyrophoric
substances, and the metals of the alkalies and earths, have in turn been
designated as the cause of intensely active volcanic phenomena. The great
chemist, Sir Humphrey Davy, to whom we are indebted for the knowledge of the
most combustible metallic
p 236
substances, has himself renounced his bold chemical hypothesis in his last
work ('Consolation in Travel, and last Days of a Philosopher') -- a work
which can not fail to excite in the reader a feeling of the deepest
melancholy. the great mean density of the earth (5.44), when compared with
the specific weight of potassium (0.865), of sodium (-.972), or of the
metals of the earths (1.2), and the absence of hydrogen gas in the gaseous
emanations from the fissures of craters, and from still warm streams of
lava, besides many chemical considerations, stand in opposition with the
earlier conjectures of Davy and Ampere.*
[footnote] *See Berzelius and Wohler, in Poggend., 'Annalen', bd. i., s.
221, and bd. xi., s. 146; Gay-Lussac, in the 'Annals de Chimie', t. x.,
xii., p. 422; and Bischof's 'Reasons against the Chemical Theory of
Volcanoes', in the English edition of his 'Warmelehre', p.
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