[152]
There is a remarkable instance of ice occurring under lava, near the
_Casa Inglese_ on Mount Etna, which it may be as well to mention, though
the causes of its existence have probably nothing in common with the
phenomena of ice-caves, or summer ice. An account of it is to be found
in Sir Charles Lyell's 'Elements of Geology.'[153] It appears that the
summer and autumn of 1828 were so hot, that the artificial ice-houses of
Catania and the adjoining parts of Sicily failed. Signer M. Gemmellaro
had long believed that a small mass of perennial ice at the foot of the
highest cone of Etna was only a part of a large and continuous glacier
covered by a lava current, and from this he expected to derive an
abundant supply of ice. He procured a large body of workmen, and
quarried into the ice; but though he thus proved the superposition of
lava for several hundred yards, the ice was so hard, and the expense of
quarrying consequently so great, that the works were abandoned. This was
on the south-east of the cone, not far from the _Casa Inglese_. Sir
Charles Lyell suggests that, probably, at the commencement of some
eruption, a large mass of snow has been thickly covered with volcanic
sand, showered upon it before the arrival of the lava itself.
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