Ice-Caves of France and Switzerland

by G. F. Browne

At first sight, the farther end of the cave was the most striking. The water which comes from the melting snow down which we had passed in reaching the glacière, had cut itself deep channels in the floor, and through these it coursed rapidly till it precipitated itself into a large pit or moulin in the ice, at the lowest point. This pit, as will be seen by the section of the cave given on p. 174,[^[71]] terminates the glacière; and the rock-wall at the farther edge falls away into a sort of open fissure, down which magnificent cascades of ice stream emulously, clothing that side of the pit, which would otherwise be solid rock. We cut a few steps about the upper edge of this moulin, to make all safe, and proceeded to let down a lighted candle, which descended safely for 36 feet, showing nothing but ice on all sides; it then came in contact with one of the falls of water, and the light was of course extinguished. We next tied a stone to the string, and found that after 40 feet it struck on ice and turned inwards, under our feet, stopping finally at the end of 51 feet; but whether it was really the bottom of the pit that stopped it, or only some ledge or accidental impediment, we could not determine. The diameter of this pit might be 3 yards, but we took no measure of it.

At the extreme right of the cave we found another pit, a yard and a half across, two-thirds of the circumference of which was formed by the plateau of ice on which we stood, and the remaining third by a fluting in the wall of rock. The maire said that, two years ago, this hole was not visible, being concealed by a large ice-column which had since fallen in. Here again I let down a lighted candle, with more hopes of getting it to the bottom, as no part of the cave drained into the pit. The candle descended steadily, the flame showing no signs of atmospheric disturbance, and revealing the fact that the opposite side of the pit, viz. the rock, which alone was visible from our position, became more and more thickly covered with ice, of exquisite clearness, and varied and most graceful forms. As foot after foot, and yard after yard, ran out, and our heads craned farther and farther over the edge of the pit to follow the descending light, (we lay flat on the ice, for more safety,) the cries of the schoolmaster became mere howls, and the maire lapsed into oaths heavy enough to break in the ice. It is always sufficiently disagreeable to hear men swear; but in situations which have anything impressive, either of danger or of grandeur, it becomes more than ever unbearable. I remember on one occasion over-taking a large party in the descent from the Plateau to the Grands Mulets, in a place where the snow was extremely soft, and any moment might land one of us in a crevasse; and I shall never forget the oaths which caught my ear, from a floundering fellow-countryman enveloped from the waist downwards.

When 60 feet had run out, the candle stopped, and on stretching over I saw that it had reached a slope of ice which inclined very steeply northwards, and passed away under the rock, apparently into a fresh cavern. By raising the candle slightly and then letting it drop, we made it glide down this slope for 8 feet; and then it finally rested on a shelf of ice, showing us the shadowy beginnings of what should be a most glorious ice-cave. The little light which the candle gave was made the most of by the reflecting material which surrounded it; and we were able to see that the archway in the rock was rounded off with grey ice, and rested, as it were, on icy pillars. As far as we could judge, there would have been abundant room to pass down the slope under the archway, if only the preliminary 60 feet could by any means have been accomplished; and I shall dream for long of what there must be down there.

As I was anxious to know whether the side of the pit was vertical ice under our feet, I contrived to get about a third of the way round the edge, so as almost to reach the fluting in the rock which formed the farther side of the pit, and then desired the schoolmaster to raise the candle slowly from the ledge on which it still rested. As he pulled it gradually up, I was startled to find that the ice fell away sharply immediately below the spot where we had been collected, and then formed a solid wall; so that we had been standing on the mere edge of a shelf, with nothing but black emptiness below. How far the solid wall receded at the bottom I was unable to determine, for the light of one candle was of very little use at so great a distance, and in darkness so profound. I persuaded the maire to make an effort to reach a point from which he could see the insecurity of the ice which had seemed to form so solid a floor; and he was so much impressed by what he saw, that he fled with precipitation from the cave, and we eventually found him asleep under a bush on the rocks above. In reaching the farther side of the pit, we crossed unwittingly an ice-bridge formed by a transverse pit or tunnel in the ice, which opened into the pit we were examining. The maire afterwards promised to rail off all that end of the glacière, and forbid his workmen to venture upon it. Considering that the hole itself was only opened two years before by the fall of a column, and has already undergone such changes, I shall be surprised if the ice-bridge, and all that part on which we lay to fathom the pit, does not fall in before very long; and then, by means of steps and ropes and ladders, it may be possible to reach the entrance to the lower cave, 190 feet below the surface of the earth. May I be there to see![^[72]]

The left side of the glacière, near the entrance, was occupied by a columnar cascade, behind which I forced a passage by chopping away some lovely ornaments of ice. Here also the solid ground-ice falls away a little under the surface, leaving a cavern 8 or 9 feet deep, on the rock side of which every possible glacial fantasy was to be found. The stalactites here presented the peculiar prismatic structure so often noticed; but on the more exposed side of the column they were tipped with limpid ice, free from all apparent external or internal lines. This reminded me of what we had observed in the Glacière of La Genollière, namely, that the surface-lines tended to disappear under thaw; so I cut a piece of prismatic ice and put it in my mouth. In a short time it became perfectly limpid, and on breaking it up I could discover no signs of prism. On some parts of the floor of the glacière, the ice was apparently unprismatic, generally in connection with running water or other marks of thaw; but, to my surprise, I found that it split into prisms very readily.

The maire could not understand how it was that, after a winter especially severe, as that of 1863-4 had been, there should be even less ice than in the preceding summer, and we could see the marks of last year's cutting, down to the edge of the moulin. He said that they had never before cut down in that direction; but in the summer of 1863 they had been so much struck by the clearness of the ice which formed the floor, that they had cut it freely, and removed a large quantity. This, I believe, was the cause of the absence of any great amount of fresh ice. The slope of the whole ice-floor is considerable, and the workmen increased the slope by cutting away the ice in the neighbourhood of the edge of the moulin: they had also, as we could see quite plainly, excavated the clearer parts of the ice between the entrance to the cave and the moulin, so that a sort of trough ran down from near the foot of the snow to the pit at the lower end of the glacière. When we were there, the water rushed down this trough, and was lost in the pit; and very probably the same may have been the case in the earlier parts of the year, when, according to the view I have already expressed, the ice would under ordinary circumstances have been formed. If this be so, the caverns below must have received immense additions to their stores of ice or water. We observed, by the way, that the slope of ice to which the candle descended in the deeper pit, and the shelf on which it rested, were quite dry, or at any rate free from all apparent signs of the abundant water we should have seen, had that been the outlet for the streams which poured into the moulin. The maire said that the columns and cascades of ice in the cave had been much more beautiful in the previous summer.

The whole cavern would thus appear to be something of the shape of an egg, with the longer axis vertical, and the entrance about half-way up the side. The lower end of this egg-shaped cavity in the rock is filled with ice, which in some parts shrinks from the rock below the surface, though, as far as outward appearance goes, it fills the cavern to its farthest corners. The depth of this ice at one side is 60 feet, and how much more it may be in the middle it is impossible to say. As we have seen, there is a second ice-cave opening out of the principal one, at a depth of 190 feet below the surface; and with respect to this second cave imagination may run riot. Rosset told me that he had noticed, the year before, a strong source of water springing out of the side of a rock, at some little distance from the glacière; but he could not reach it then, and could not find it now. This may possibly be the drainage of the glacière in its summer state.

The thermometer stood at 34° in the middle of the cave; and though the others felt the cold very much, I was myself surprised to find so low a register, for the atmosphere seemed to be comparatively warm, judging from what I had experienced in other glacières. The only current of air we could detect was exceedingly slight, and came from the deeper of the two pits in the ice. It was so slight, that the flame of the candle burned apparently quite steadily when we were engaged in determining the depth and shape of the pit.

The sun had by this time produced such an effect upon the slope of snow outside the glacière, that we found the ascent sufficiently difficult, especially as our hands were full of various instruments. The schoolmaster was not content to choose the straight line up, and in attempting to perform a zigzag, he came to a part of the slope where the snow lay about 2 inches thick on solid ice, and the result was an unscholastic descent in inverted order of precedence. He got on better over the rolling stones after the snow was accomplished, but the clumsy style of his climbing dislodged an unpleasant amount and weight of missiles; and though he was amiable enough to cry 'Garde!' with every step he took, it will be found by experiment that it is not much use to the lower man to have 'Garde!' shouted in his ears, when his footing is insecure to begin with, and a large stone comes full at his head, at the precise moment when two others are taking him in the pit of the stomach.

We found the maire, as was said, asleep under a bush near the mouth of the pit; and he pronounced himself completely recovered from the effects of the cold, and ready to guide us to a second glacière. He told us that the amount of ice he sold averaged 4,000 quintaux métriques a week, for the three months of July, August, and September; but the last winter had been so severe, that the lake had provided ice for the artificial glacières of Annecy, and no one had as yet applied to him this year. As only a fortnight of his usual season had passed, he may have since had plenty of applications, later in the year. The railways have opened up more convenient sources of ice for Lyons, and for some time he has sent none to that town.