depth
from which their waters come forth.

As the accidents of volcanic explosion are of a nature to be very
damaging to man, as well as to the lower orders of Nature, it is fit
that we should note in general the effect of the Neapolitan eruptions
on the history of civilization in that region. As stated above, the
first Greek settlements in this vicinity--those on the island of
Ischia--were much disturbed by volcanic outbreaks, yet the island
became the seat of a permanent and prosperous colony. The great
eruption of 79 probably cost many hundred lives, and led to the
abandonment of two considerable cities, which, however, could at small
cost have been recovered to use. Since that day various eruptions have
temporarily desolated portions of the territory, but only in very
small fields have the ravages been irremediable. Where the ground was
covered with dust, it has in most places been again tillable, and so
rapid is the decay of the lavas that in a century after their flow has
ceased vines can in most cases be planted on their surfaces. The city
of Naples, which lies amid the vents, though not immediately in
contact with any of them, has steadfastly grown and prospered from the
pre-Christian times. It is doubtful if any lives have ever been lost
in the city in consequence of an eruption, and no great inconvenience
has been experienced from them. Now and then, after a great ash
shower, the volcanic dust has to be removed, but the labour is less
serious than that imposed on many northern cities by a snowstorm.
Through all these convulsions the tillage of the district has been
maintained. It has ever been the seat of as rich and profitable a
husbandry as is afforded by any part of Italy. In fact, the ash
showers, as they import fine divided rock very rich in substances
necessary for the growth of plants, have in a measure served to
maintain the fertility of the soil, and by this action have in some
degree compensated for the injury which they occasionally inflict.
Comparing the ravages of the eruptions with those inflicted by war,
unnecessary disease, or even bad politics, and we see that these
natural accidents have been most merciful to man. Many a tyrant has
caused more suffering and death than has been inflicted by these rude
operations of Nature.

From the point of view of the naturalist, AEtna is vastly more
interesting than Vesuvius. The bulk of the cone is more than twenty
times as great as that of the Neapolit