decked with ice precisely as might be expected.[9] Another possible
explanation of this curious and beautiful phenomenon will be given
hereafter.[10]

The temperature was half a degree lower than when there were three of us
in the cave two days before. I deposited one of Casella's registering
thermometers, on wood, on a stone in that part of the floor which was
free from ice, though there was ice all round it at some little
distance. The thermometer was well above the surface of the ice, and
was protected from chance drops of water from the roof.

The next morning I started early from Arzier, having an afternoon
journey in prospect to the neighbourhood of another glacière, and was
accompanied by Captain Douglas Smith, of the 4th Regiment. On our way to
La Genollière, we came across the man who had served as guide the day
before, and a short conversation respecting the glacière ensued. He had
only seen it once, many years before, and he held stoutly to the usual
belief of the peasantry, that the ice is formed in summer, and melts in
winter; a belief which everything I had then seen contradicted. His last
words as we parted were, '_Plus il fait chaud, plus ça gèle_;' and,
paradoxical as it may appear, I believe that some truth was concealed in
what he said, though not as he meant it. Considering that his ideas were
confined to his cattle and their requirements, and that water is often
very difficult to find in that part of the Jura, a _hot_ summer would
probably mean with him a _dry_ summer, that is, a summer which does not
send down much water to thaw the columns in the cave. Extra heat in the
air outside, at any season, does not, as experience of these caves
proves abundantly, produce very considerable disturbance of their low
temperature, and so summer water is a much worse enemy than extra summer
heat; and if the caves could be protected from water in the hot season,