8 Prof. Pictet on the Ice-caves of' the Jura and the Alps . 
From thence there is scarcely any ascent to the village of Bre- 
zon, where we arrived at half-past twelve o’clock. The guide 
to whom we trusted was absent ; but chance procured us ano- 
ther. We set out immediately with our guide, for the Ice Cave, 
which was much more distant than one hour’s walk. We found 
by the barometer, that our guide’s house, from whence we de- 
parted, was 314 toises above the lake. The weather being bad, 
and having caught a severe cold, I resolved to leave the prose- 
cution of it to my grandson, Edward Prevost, who ascended to 
the Ice Cave with the guide. I shall give the following account 
of it in the words of my grandson. 
44 The guide and I ascended till we arrived at the base of 
that immense inclined face of rock, which descends from the 
chain of Mount Vergy, and whose barren and desolated aspect 
makes it visible from a great distance, especially at sunset. This 
platform terminates in an abrupt manner, descending to the 
north towards the region of wood. We followed for some time 
this natural wall, from left to right, and, after a slight turn to 
the left, we reached a place, where a strong current of very 
cold air issued from an opening in the rock, about two feet from 
the ground. The thermometer, which in the open air stood 
at 51°, when exposed to this current fell immediately to 38°|. 
About ten toises farther, at the foot of the same natural wall, 
surmounted by the desert already mentioned, we found the Ice 
Cave. The entrance is small, and partly obstructed by calca- 
reous blocks, which appear to have fallen from the roof. A lit- 
tle farther in, we found ourselves in a cavity of a very irregular 
form, into which the daylight, and also the winter’s snow, pene- 
trates by an opening in the form of a funnel, and which the 
snow still partly obstructed. 
44 The extremity opposite to the entrance is so low, that the 
guide was obliged to stoop very much, in placing the end of the 
ribbon, which we made use of to measure with. The greatest 
length of the grotto was only thirty feet ; its breadth, which is 
very irregular, was about twenty-five, and its height ten or 
twelve at most. 
44 The temperature of the interior was 41°. The barometer 
at the entrance was 24. 1,8, which gives 148.1 toises for the 
