d a diameter of about 100 metres, was
formed at this point. It is composed of a prehistoric grey labradorite,
and of doleritic lava. Downwards from the main crater, in the direction
of Monte di Mojo, a long fissure extended for 400 metres, and along the
line of this fissure no less than _thirty-five_ minor cones opened, with
craters of from thirty to three metres in diameter. The stream of lava
ejected from the various _boccarelle_ was 400 metres long, 80 wide, and
2 metres in thickness, and the bulk of volcanic material brought to the
surface, including the principal cone and its thirty-five subordinates
and their ejectamenta, was calculated to amount to 1,351,000 cubic
metres. The lava is of an augitic character, and magnetic; it possesses
a specific gravity of 2.3636 at 25 deg. C.

It will be seen from the account of the foregoing eruptions that there
is a great similarity in the character of the eruptions of Etna.
Earthquakes presage the outburst; loud explosions follow, rifts and
_bocche del fuoco_ open in the sides of the mountain; smoke, sand,
ashes, and scoriae are discharged, the action localises itself in one or
more craters, cinders are thrown up, and accumulate around the crater
and cone, ultimately lava rises, and frequently breaks down one side of
the cone, where the resistance is least. Then the eruption is at an
end.

Smyth says, "The symptoms which precede an eruption are generally
irregular clouds of smoke, ferilli, or volcanic lightnings, hollow
intonations, and local earthquakes that often alarm the surrounding
country as far as Messina, and have given the whole province the name of
Val Demone, as being the abode of infernal spirits. These agitations
increase until the vast cauldron becomes surcharged with the fused
minerals, when, if the convulsion is not sufficiently powerful to force
them from the great crater (which, from its great altitude and the
weight of the candent matter, requires an uncommon effort), they explode
through that part of the side which offers the least resistance with a
grand and terrific effect, throwing red-hot stones and flakes of fire to
an incredible height, and spreading ignited cinders and ashes in every
direction." After the eruption of ashes, lava frequently follows,
sometimes rising to the top of the cone of cinders, at others breaching
it on the least resisting side. When the lava has reached the base of
the cone, it begins to flow down the mountain, and being then