here was no strong wind, and we did
not suffer from the sickness of which travellers constantly complain in
the rarefied air of the summit. We reached the highest point at 4.30
a.m., and found a temperature of 47 deg. F.

When Sir William Hamilton ascended towards the end of June the
temperature at the base of the mountain was 84 deg. F., and at the summit
56 deg. F. When Brydone left Catania on May 26th, 1770, the temperature was
76 deg. F., Bar. 29 in. 8-1/2 lines; at Nicolosi at midday on the 27th it
was 73 deg. F., Bar. 27 in. 1-1/2 lines; at the Spelonca del Capriole (6,200
feet), 61 deg. F., Bar. 26 in. 5-1/2 lines; at the foot of the crater, temp.
33 deg. F., Bar. 20 in. 4-1/2 lines, and at the summit of the crater just
before sunrise, temp. 27 deg. F., Bar. 19 in. 4 lines.

On reaching the summit we noticed that a quantity of steam and
sulphurous acid gas issued from the ground under our feet, and in some
places the cinders were so hot that it was necessary to choose a cool
place to sit down upon. A thermometer inserted just beneath the soil
from which steam issued registered 182 deg. F. For a short time we anxiously
awaited the rising of the sun. Nearly all the stars had faded away; the
vault of heaven was a pale blue, becoming a darker and darker grey
towards the west, where it appeared to be nearly black. Just before
sunrise the sky had the appearance of an enormous arched spectrum,
extremely extended at the blue end. Above the place where the sun would
presently appear there was a brilliant red, shading off in the direction
of the zenith to orange and yellow; this was succeeded by pale green,
then a long stretch of pale blue, darker blue, dark grey, ending
opposite the rising sun with black. This effect was quite distinct, it
lasted some minutes, and was very remarkable. This was succeeded by the
usual rayed appearance of the rising sun, and at ten minutes to 5
o'clock the upper limb of the sun was seen above the mountains of
Calabria. Examined by the spectroscope the Fraunhofer lines were
extremely distinct, particularly two lines near the red end of the
spectrum.

The top of the mountain was now illuminated, while all below was in
comparative darkness, and a light mist floated over the lower regions.
We were so fortunate as to witness a phenomenon which is not always
visible, viz., the projection of the triangular shadow of the mountain
across the island, a hundred miles away. The shadow appeared vertica