File:The Quarterly journal of the Geological Society of London (12683708744).jpg

1856..
SCROPE CRATERS AND LAVAS.
337
appeared in the shape of a vast funnel, accessible to its bottom,
which for a few years then remained in a tranquil state. In 1841,
however, a small cone began to form within it, and increased so
rapidly, that in 1845 it was visible from Naples above the brim of
Fig. 3. — Crater of Vesuvius after the Eruption of October 1822.
the crater, which soon after was completely filled. And the cone
from that time went on increasing in bulk and height from the effect
of minor eruptions, until in 1850 one of a violently explosive cha-
racter opened the two deep craters on its summit, of which I have
already spoken. The more recent eruption of May last, being con-
fined chiefly to a prodigious efflux of lava from the outer side of the
cone, unaccompanied by any extraordinary explosive bursts from the
summit, has not altered materially the form impressed upon it in
1850.
It is thus seen that within the last 100 years the cone of Vesuvius
has been five several times gutted by explosive eruptions of a par-
oxysmal character, viz. in 1794, 1822, 1831, 1839, and 1850; and
its central craters formed in this manner as often gradually refilled
with matter, to be again in due time blown into the air. Meanwhile
the old external crater of Somma is itself becoming choked up by
the accumulation of all the lava-streams and fragmentary matter
that are expelled towards the northern and outer side of the cone.
It would be, therefore, in exact accordance with the habit of this
volcano (as of volcanic mountains in general), if, after some further
period either of quiescence or of moderate activity, the entire cone
of Vesuvius should be blown up by a more than ordinarily violent
paroxysm, and the crater of Somma itself reformed.
With this well-authenticated history of the mountain within our
knowledge, would it not be wholly unphilosophical to deny (except
upon such grounds of impossibihty as have never been adduced)
that the larger containing crater in the case of Vesuvius (and the
argument applies to other similar volcanic mountains) had the same