xxii., p. 427, and Bischof, 'Warmelehre', s. 272. The eruptions
of smoke and steam which have at different periods been seen in Lancerote,
Iceland, and the Kurile Islands, during the eruption of the neighboring
volcanoes, afford indications of the reaction of volcanic foci through tense
columns of water; that is to say, these phenomena occur when the expansive
force of the vapor exceeds the hydrostatic pressure.
[footnote] ** [See Daubeney 'On Volcanoes', Part iii., ch. xxxvi.,
xxxviii., xxxix.] -- Tr.
The discussion of these important physical questions does not come within
the scope of a work of this nature; but, while we are considering these
phenomena, we would enter somewhat more into the question of the
geographical distribution of still active volcanoes. We find, for instance,
that in the New World, three, viz., Jorullo, Popocatepetl, and the volcano
of De la Fragua, are situated at the respective distances of 80, 132, and
196 miles from the sea-coast, while in Central Asia, as Abel Remusat* first
made known to geognosists, the Thianschan (Celestial Mountains), in which
are situated the lava-emitting mountain of Pe-schan, the solfatara of
Urumtsi, and the still active igneous mountain (Ho-tscheu) of Turfan, lie at
an almost equal distance (1480 to 1528 miles) from the shores of the Polar
Sea and those of the Indian Ocean.
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