le more than two centuries since this
famous volcanic mountain assumed its present form.

(_h._) _Eruptions between the years 1500 and 1800._--Since A.D. 1500
there have been fifty-six recorded eruptions of Vesuvius; one of these
in 1767 was of terrific violence and destructiveness, and is represented
by Sir William Hamilton in views taken both before and during the
eruption. A pen-and-ink drawing of the appearance of the crater before
the eruption is here reproduced from Hamilton's picture, from which it
will be seen that the central crater contained within itself a second
crater-cone, from whence steam, lava, and stones were being erupted
(Fig. 7). Thus it will be seen that Vesuvius at this epoch consisted of
three crater-cones within each other. The first, Monte di Somma; the
second, the cone of Vesuvius; and the third, the little crater-cone
within the second. During this eruption, vast lava-sheets invaded the
fields and vineyards on the flanks of the mountain. A vivid account of
this eruption, as witnessed by Padre Torre, is given by Professor
Phillips.[8] We shall pass over others without further reference until
we come down to our own times, in which Vesuvius has resumed its old
character, and in one grand exhibition of volcanic energy, which took
place in 1872, has evinced to the world that it still contains within
its deep-seated laboratory all the elements of destructive force which
it exhibited at the commencement of our era.

[Illustration: Fig. 7.--View of the crater of Vesuvius before the
eruption of 1767, showing an interior crater-cone rising from the centre
of the exterior crater.--(After Sir W. Hamilton.)]

(_i._) _Structure of the Neapolitan Campagna._--But before giving a
description of this terrific outburst of volcanic energy, it may be
desirable to give some account of the physical position and structure of
this mountain, by which the phenomena of the eruption will be better
understood. Vesuvius and the Neapolitan Campagna are formed of volcanic
materials bounded on the west by the Gulf of Naples, and on the east and
south by ranges of Jurassic limestone, a prolongation of the Apennines,
which send out a spur bounding the bay on the south, and forming the
promontory of Sorrento. The little island of Capri is also formed of
limestone, and is dissevered from the promontory by a narrow channel.
The northern side of the bay is, however, formed of volcanic materials;
it includes the Phlegraean Fields