abounded, only about the brims of
the craters. Hydrochloric and sulphuric acid and sometimes sulphuretted
hydrogen affected respiration, and the temperature rose sometimes to 150
degrees. Various fissures about the brim of the double crater indicated
prolongations downwards, which allowed me to descend with a rope, in
order to examine the interior of the tunnel to which I have just
alluded. The highest brim of the crater was fissured for a distance of
80 metres, and the greatest depth of fissure was at that place.

By measurement with the barometer, we ascertained approximately (for
only one barometer was used) that the height of the Vesuvian cone was
somewhat diminished.

Not only the Vesuvian cone, but the whole adjacent country appeared
white for many days, as if covered with snow, when exposed to sunlight.
This was due to the sea-salt contained in the ashes with which the
surface was strewn.

A great quantity of coleoptera assembled on the flat roof of the
Observatory, where the ashes and lapilli were heaped up two decimetres
in height. I found the same species on the cone, where many insects were
observed on other occasions, such as the _Cuccinella septempunctata_;
the crysomela populi, etc., were wanting. This phenomenon of the
extraordinary concourse of insects on the top of Vesuvius, in order to
die in some of the fumaroles, especially noted previous to and after
great eruptions, is a circumstance for which I cannot account.[4] The
whole of the lava emitted in this eruption occupies a surface of about
five square kilometres; allowing an average thickness of four metres, we
obtain a mass of twenty millions of cubic metres. About three-fifths of
this lava did no injury, being deposited upon other pre-existing lava.
However, the lava in the Novelle, which was deposited upon the lava of
1858, covered quarries of the best stone which had been worked at the
time, covered many paths that had been cleared, and buried the new
Church of St. Michele, with some houses that surrounded it, which had
been rebuilt on the site of the former church, which was covered by the
lava of 1868. The destruction of land in occupation, of buildings and of
crops, exceeded three million francs in value. Many proposals for
relieving the sufferers have been received. Wishing to aid in this
benevolent work, I gave a public lecture, admission for each person
being one franc; and this lecture, from notes badly taken, was printed
by private sp