the event, tells us that Herculaneum and Pompeii were overwhelmed; but
he mixes his story with fantastic legends concerning the appearance of
gods and demons, as is his fashion in his so-called history. Of all
the Roman writers, he is perhaps the most untrustworthy. Fortunately,
however, we have in the deposits of ashes which were thrown out at the
time of this great eruption some basis for interpreting the events
which took place. It is evident that for many hours the Vesuvian
crater, which had been dormant for at least five hundred years, blew
out with exceeding fury. It poured forth no lava streams; the energy
of the uprushing vapours was too great for that. The molten rock in
their path was blown into fine bits, and all the hard material cast
forth as free dust. In the course of the eruption, which probably did
not endure more than two days, possibly not more than twenty-four
hours, ash enough was poured forth to form a thick layer which spread
far over the neighbouring area of land and sea floor. It covered the
cities of Herculaneum and Pompeii to a depth of more than twenty feet,
and over a circle having a diameter of twenty miles the average
thickness may have been something like this amount. So deep was it
that, although almost all the people of these towns survived, it did
not seem to them worth while to undertake to excavate their dwelling
places. At Pompeii the covering did not overtop the higher of the low
houses. An amount of labour which may be estimated at not over one
thirtieth of the value, or at least the cost which had been incurred
in building the city, would have restored it to a perfectly
inhabitable state. The fact that it was utterly abandoned probably
indicates a certain superstitious view in connection with the
eruption.

The fact that the people had time to flee from Herculaneum and
Pompeii, bearing with them their more valuable effects, is proved by