VERTICAL SECTION OF THE GLACIÈRE OF GRÂCE-DIEU, NEAR BESANÇON.
Immediately below the portal I found a piece of the trunk of a large column of ice, 7 feet long and 12 feet in girth, its fractured ends giving the idea of the interior of a quickly-grown tree, in consequence of the concentric arrangement of convergent prisms described in the account of the Glacière of S. Georges. The wife of the farmer told me afterwards that there had been two glorious columns at this portal, which the recent rains had swept away. Excepting a short space at the foot of the slope, and another towards the farther end of the cave, the floor was covered with ice, in some parts from 3 to 4 feet thick: of this a considerable area had been removed to a depth of 2 1/2 or 3 feet, leaving a pond of water a foot deep, with bottom and banks of ice. The rock which composes the true floor rises at the farthest end of the cave, and the roof is so arranged that a sort of private chapel is there formed; and from a fissure in the dome a monster column of ice had been constructed on the floor, which, at the time of my visit, had lost its upper parts, and stood as a hollow truncated cone with sides a foot thick, and with seas of ice streaming from it, and covering the rising pavement of the chapel. Without an axe, and without help, I was unable to measure the girth of this column, which had not been without companions on a smaller scale in the immediate neighbourhood. At the west end of the cave, the wall was thickly covered for a large space with small limestone stalactites, producing the effect of many tiers of fringe on a shawl; while from a dark fissure in the roof a large piece of fluted drapery of the same material hung, calling to mind some of the vastly grander details of the grottoes of Hans-sur-Lesse in Belgium: down this wall there was also a long row of icicles, on the edges of a narrow fissure. The north-west corner was very dark, and an opening in the wall of rock high above the ground suggested a tantalising cave up there: the ground in this corner was occupied by the shattered remains of numerous columns of ice, which had originally covered a circular area between 60 and 70 feet in circumference.
The three large masses of ice which rendered this glacière in some respects more remarkable than any of those I have seen, lay in a line from east to west, across the middle of the cave, on that part of the floor where the ice was thickest. The central mass was extremely solid, but somewhat unmeaning in shape, being a rough irregular pyramid; its size alone, however, was sufficient to make it very striking, the girth being 66-1/2 feet at some distance from the ice-floor with which it blended. The mass which lay to the east of this was very lovely, owing to the good taste of some one who had found that much ice was wont to accumulate on that spot, and had accordingly fixed the trunk of a small fir-tree, with the upper branches complete, to receive the water from the corresponding fissure in the roof. The consequence was, that, while the actual tree had vanished from sight under its icy covering, excepting on one side where a slight investigation betrayed its presence, the mass of ice showed every possible fantasy of form which a mould so graceful could suggest. At the base, it was solid, with a circumference of 37 feet. The huge column, which had collected round the trunk of the fir-tree, branched out at the top into all varieties of eccentricity and beauty, each twig of the different boughs becoming, to all appearance, a solid bar of frosted ice, with graceful curve, affording a point of suspension for complicated groups of icicles, which streamed down side by side with emulous loveliness. In some of the recesses of the column, the ice assumed a pale blue colour; but as a rule it was white and very hard, not so regularly prismatic as the ice described in former glacières, but palpably crystalline, showing a structure not unlike granite, with a bold grain, and with a large predominance of the glittering element. But the westernmost mass was the grandest and most beautiful of all. It consisted of two lofty heads, like weeping willows in Carrara marble, with three or four others less lofty, resembling a family group of lions' heads in a subdued attitude of grief, richly decked with icy manes. Similar heads seemed to grow out here and there from the solid sides of the huge mass. The girth was 76 1/2 feet, measured about 2 feet from the floor. When this column was looked at from the side removed from the entrance to the cave, so that it stood in the centre of the light which poured down the long slope from the outer world, the transparency of the ice brought it to pass that the whole seemed set in a narrow frame of impalpable liquid blue, the effect of light penetrating through the mass at its extreme edges. The only means of determining the height of this column was by tying a stone to the end of a string, and lodging it on the highest head; but this was not an easy process, as I was naturally anxious not to injure the delicate beauty which made that head one of the loveliest things conceivable; and each careful essay with the stone seemed to involve as much responsibility as taking a shot at a hostile wicket, in a crisis of the game, instead of returning the ball in the conventional manner. When at last it was safely lodged, the height proved to be 27 feet. I had hoped to find it much more than this, from the grandeur of the effect of the whole mass, and I took the trouble to measure the knotted string again with a tape, to make sure that there was no mistake. The column formed upon the fir-tree was 3 or 4 feet lower.
I have since found many notices of this glacière in the Memoirs of the French Academy and elsewhere, extracts from which will be found in a later chapter. These accounts are spread over a period of 200 years, extending from 1590 to 1790, and almost all make mention of the columns or groups of columns I have described; but, without exception, the heights given or suggested in the various accounts are much less than those which I obtained as the result of careful measurement. The latest description of a visit to the glacière states a fact which probably will be held to explain, the present excess of height above that of earlier times.[[37]] The citizen Girod-Chantrans, who wrote this description, had procured the notes of a medical man living in the neighbourhood, from which it seemed that Dr. Oudot made the experiment, in 1779, of fixing stakes of wood in the heads of the columns, then from 4 to 5 feet high, and found that these stakes were the cause of a very large increase in the height of the columns, ice gathering round them in pillars a foot thick. So that it is not improbable that the largest of the three masses of the present day owes its height, and its peculiar form, to a series of stakes fixed from time to time in the various heads formed under the fissures in the roof, though nothing but the most solid ice can now be seen. It would be very interesting to try this experiment in one of the caves where, without any artificial help, such immense masses of ice are formed; and by this means columns might, in the course of a year or two, be raised to the very roof. Further details on this subject will be given hereafter.
There was no perceptible draught of air in any part of the cave, and the candles burned steadily through the whole time of my visit, which occupied more than two hours. The centre was sufficiently lighted by the day; but in the western corner, and behind the largest column, artificial light was necessary. The ice itself did not generally show signs of thawing, but the whole cave was in a state of wetness, which made the process of measuring and investigating anything but pleasant. I had placed two thermometers at different points on my first entrance--one on a drawing-board on a large stone in the middle of the pond of water which has been mentioned, and the other on a bundle of pencils at the entrance of the end chapel, in a part of the cave where the ice-floor ceased for a while, and left the stones and rock bare. The former gave 33°, the latter, till I was on the point of leaving, 31 1/2°, when it fell suddenly to 31°. It was impossible, however, to stay any longer for the sake of watching the thermometer fall lower and lower below the freezing point; indeed, the results of sundry incautious fathomings of the various pools of water, and incessant contact of hands and feet with the ice, had already become so unpleasant, that I was obliged to desert my trusty hundred feet of string, and leave it lying on the ice, from want of finger-power to roll it up. The thermometers were both Casella's, but that which registered 31° was the more lively of the two, the other being mercurial, with a much thicker stem: the difference in sensitiveness was so great, that when they were equally exposed to the sun in driving home, the one ran up to 93° before the other had reached 85°.
In leaving the glacière, I found a little pathway turning off along the face of the rock on the left hand, a short way up the slope of entrance, and looking as if it might lead to the opening in the dark wall on the western side of the cave. After a time, however, it came to a corner which it seemed an unnecessary risk to attempt to pass alone; and my prudence was rewarded by the discovery that, after all, the supposed cave could not be thus reached. It is said that this other cave was the place to which the inhabitants fled for refuge when their district was invaded, probably by the Duke of Saxe-Weimar with his 10,000 Swedes, and that a ladder 40 feet long is necessary for getting at it.
The driver had long ago absconded when I returned to the upper regions; but the wife of the farmer of the grotto was there, and communicated all that she knew of the statistics of the ice annually removed. She said that in 1863 two chars were loaded every day for two months, each char taking about 600 kilos, the wholesale price in Besançon being 5 francs the hundred kilos. Since the quintal contains 50 kilos, it will be seen that this account does not agree with the statement of Renaud as to the amount of ice each char could take. No doubt, a char at S. Georges may mean one thing, and a char in the village of Chaux another; but the difference between 12 quintaux and 50 or 60 is too great to be thus explained, and probably Madame Briot made some mistake. Her husband, Louis Briot, works alone in the cave, and has twelve men and a donkey to carry the ice he quarries to the village of Chaux, a mile from the glacière, where it is loaded for conveyance to Besançon. He uses gunpowder for the flooring of ice, and expects the eighth part of a pound to blow out a cubic metre; and if, by ill luck, the ice thus procured has stones on the lower side, he has to saw off the bottom layer. Madame Briot said I was right in supposing March to be the great time for the formation of ice, as she had heard her husband say that the columns were higher then than at any other time of the year: she also confirmed my views as to the disastrous effects of heavy rain. As with every other glacière of which I could obtain any account, excepting the Lower Glacière of the Pré de S. Livres, she complained that the ice had not been so beautiful and so abundant this year as last, although the winter had been exceptionally severe.