llo, forming the wall of the ancient crater throughout half its
circumference; this wall is formed of scoriae, ashes, and lapilli, and is
traversed by numerous dykes of lava. Along the west and south this old
crater has been broken down; but near the centre there remains a
round-backed ridge of similar materials, once doubtless a part of the
original crater of Somma, rising above the slopes of lava on either
hand. On this has been erected the Royal Observatory, under the
superintendence of Professor Luigi Palmieri, where continuous
observations are being made, by means of delicate seismometers, of the
earth-tremors which precede or accompany eruptions; for it is only
justice to say that Vesuvius gives fair warning of impending mischief,
and the instruments are quick to notify any premonitory symptoms of a
coming catastrophe. The elevation of the Observatory is 2080 feet above
the sea.

On either side of the Observatory ridge are wide channels filled to a
certain height with lavas of the nineteenth and preceding centuries, the
most recent presenting an aspect which can only be compared to a
confused multitude of black serpents and pachyderms writhing and
interlocked in some frightful death-struggle. Some of this lava, ten
years old, as we cross its rugged and black surface presents gaping
fissures, showing the mass to be red-hot a few feet from the surface, so
slow is the process of cooling. These lava-streams--some of them
reaching to the sea-coast--have issued forth from the Atria at
successive periods of eruption.

From the midst of the Atria rises the central cone, formed of cinders,
scoriae, and lava-streams, and fissured along lines radiating from the
axis. This cone is very steep, the angle being about 40 deg.-45 deg. from the
horizontal, and is formed of loose cindery matter which gives way at
every step, and is rather difficult to climb. But on reaching the summit
we look down into the crater, displaying a scene of ever-varying
characters, rather oval in form, and about 1100 yards in diameter. From
the map of Professor Guiscardi, published in 1855, there are seen two
minor craters within the central one, formed in 1850, and an outflow of
lava from the N.W. down the cone. At the time of the author's visit the
crater was giving indications, by the great quantity of sulphurous gas
and vapour rising from its surface, and small jets of molten lava
beginning to flow down the outer side, of the grand outburst of inter