Rosset now told me he was so cold he could stand it no longer; but, after a little pressure, and a declaration on my part that he should not have a candle for going up again, he consented to remain with me while I explored the remaining chamber, the lowest of all.  This chamber may be called a continuation of the main passage.  It is of about the same width as the highest of the three chambers, and the floor descends rapidly, the cold current of air becoming very strong and biting as we penetrated into the darkness.  As the Genevese savans seemed to believe in ’cold currents’ as the cause of underground ice, I was naturally anxious to see as much as possible of the state of this gallery, from which every particle of the current seemed to come.  We very soon reached a narrow dark lake, and, exclaiming that here was ice again, I stepped, not on to, but into it, and found that it was water.  When our solitary candle was brought to bear upon it, we saw that it was so clear as not in any way to impede our view, producing rather the effect of slightly-clouded spectacles upon the stones at the bottom.  This lake filled up the whole breadth of the gallery, here perhaps 4 or 5 feet, and rapidly passed to the depth of a yard; but for a little distance there were unstable stones at one edge, and steps in the rock-wall, by which I could pass on still into the darkness, supported by an alpenstock planted in the water.  The current of cold air blew along the surface of the water from the farther extremity of the gallery, wherever that might be.  As far as our eyes could reach, we saw nothing but the black channel of water, with its precipitous sides passing up beyond our sight.  It might have been possible to progress in a spread-eagle fashion, with one hand and one foot on each side; but a fall would have been so bitterly unpleasant, that I made a show of condescension in acceding to Rosset’s request that I would not attempt such a thing.  In the course of my return to the rocks where he stood, I involuntarily fathomed the depth of the lake, luckily in a shallower part, and was so much struck by the coldness of the water, that I left Rosset with the candle, and struggled up without a light to the place where we had left the maire, or rather to the bottom of the drop from the entrance-cave, to get the thermometer.  The maire was sunning himself on the rock, out of reach of the cold current; but he came in, and let down the case, and I quickly rejoined the schoolmaster.  At first, it would have been impossible to move about without a light; but our eyes had now become to some extent accustomed to the darkness, and I had learned the difficulties of the way.