e by
the melted stuff cooling and hardening again into stone, it was burst in
another place, and a fresh volcano made, or an old one re-opened.

Now we can understand why earthquakes should be most common round
volcanos; and we can understand, too, why they would be worst before a
volcano breaks out, because then the steam is trying to escape; and we
can understand, too, why people who live near volcanos are glad to see
them blazing and spouting, because then they have hope that the steam has
found its way out, and will not make earthquakes any more for a while.
But still that is merely foolish speculation on chance. Volcanos can
never be trusted. No one knows when one will break out, or what it will
do; and those who live close to them--as the city of Naples is close to
Mount Vesuvius--must not be astonished if they are blown up or swallowed
up, as that great and beautiful city of Naples may be without a warning,
any day.

For what happened to that same Mount Vesuvius nearly 1800 years ago, in
the old Roman times? For ages and ages it had been lying quiet, like any
other hill. Beautiful cities were built at its foot, filled with people
who were as handsome, and as comfortable, and (I am afraid) as wicked, as
people ever were on earth. Fair gardens, vineyards, olive-yards, covered
the mountain slopes. It was held to be one of the Paradises of the
world. As for the mountain's being a burning mountain, who ever thought
of that? To be sure, on the top of it was a great round crater, or cup,
a mile or more across, and a few hundred yards deep. But that was all
overgrown with bushes and wild vines, full of boars and deer. What sign
of fire was there in that? To be sure, also, there was an ugly place
below by the sea-shore, called the Phlegraen fields, where smoke and
brimstone came out of the ground, and a lake called Avernus over which
poisonous gases hung, and which (old stories told) was one of the mouths
of the Nether Pit. But what of that? It had never harmed any one, and
how could it harm them?

So they all lived on, merrily and happily enough, till, in the year A.D.
79 (that was eight years, you know, after the Emperor Titus destroyed
Jerusalem), there was stationed in the Bay of Naples a Roman admiral,
called Pliny, who was also a very studious and learned man, and author of
a famous old book on natural history. He was staying on shore with his
sister; and as he sat in his study she called him out to