nths; and two years after it had ceased to flow it was
found to be red hot beneath the surface. Even eight years after the
eruption quantities of steam escaped from the lava after a shower of
rain. The stones which were ejected from the crater during this eruption
were often of considerable magnitude, and Borelli calculated that the
diameter of one which he saw was 50 feet; it was thrown to a distance of
a mile, and as it fell it penetrated the earth to a depth of 23 feet.
The volume of lava emitted during this eruption amounted to many
millions of cubic feet: Ferrara considers that the length of the stream
was at least fifteen miles, while its average width was between two and
three miles, so that it covered at least forty square miles of surface.

In a somewhat rare tract,[19] Lord Winchelsea, who was returning to
England from Constantinople, and who landed at Catania, gives an account
of what he saw of the eruption. He appears to have been frightened at
the sight, and took good care to keep in a safe place; hence his letter,
which is a short one, is mainly founded on hearsay. However, he says, "I
could discern the river of fire to descend the mountain, of a terrible
fiery or red colour, and stones of a paler red to swim thereon, and to
be as big as an ordinary table.... Of 20,000 persons which inhabited
Catania, 3000 did only remain; all their goods are carried away, the
cannon of brass are removed out of the castle, some great bells taken
down, the city gates walled up next the fire, and preparations made by
all to abandon the city." The noble earl is less happy in his scientific
ideas than in his general statement of the facts of which he was an
eye-witness; we can only hope that he joined the recently-formed Royal
Society on his return to England, and listened to Robert Hooke's
discourse on fire. In describing the lava, Lord Winchelsea says, "The
composition of this fire, stones, and cinders, are sulphur, nitre,
quicksilver, sal-ammoniac, lead, iron, brass, and all other mettals!"
Two other accounts are appended to the above letter; in one of these we
are told that as the lava approached Catania, the various religious
bodies carried their relics in procession, "followed by great multitudes
of people, some of them mortifying themselves with whips, and other
signs of penance, with great complaints and cries, expressing their
dreadful expectation of the events of those prodigious fiery
inundations." In the midst of al