The air in the cave seemed absolutely still throughout; it was also extremely dry, undoubtedly because melting had not yet begun. The icicles evidently were formed by the slow drip freezing as it descended, and there were no perceptible cracks nor fissures in the rocks underneath them. The facts seem to me to prove that neither evaporation nor regelation can be the factors at work in making the ice and we may deduce an important rule therefrom. When a cave is dry, then the air is dry; when a cave is wet, then the atmosphere is damp. In other words, the state of dryness or dampness of glacière atmosphere depends on how much the ice is thawing and parting with its moisture.
On our return to the base of the long staircase, and while we ascended it, we had an exquisite moonlight effect, much resembling the one at the Schafloch.
THE FRAINER EISLEITHEN.
About two hours by rail, north of Vienna, is the village of Schoenwald, to which I journeyed on June the 15th, 1896. At the railroad station there was a K. K. Post Omnibus in waiting, which, when it was packed with passengers and luggage, drove over to Frain in an hour. The admirable road lies across a rolling plain, until it reaches the brink of the valley of the Thaya, to which it descends in long Alpine zigzags. On the bluff overlooking the opposite side of the river, there is a fine schloss.
I secured the seat next to the driver and questioned him about the Eisleithen. Although he had driven on this road for five years, without visiting the Eisleithen, yet he was positive that they were warm in winter, but cold in summer. He said more than once: Desto heisser der Sommer, desto mehr das Eis, and in fact was an emphatic exponent of the notions generally held by peasants, which some savants have adopted and tried to expound. At Frain, I applied at the little hotel for a guide, and was entrusted to the care of the hotel boots. He was an intelligent, talkative youth, but he insisted also that “the hotter the summer, the more ice there is.” However, he was polite, and made up for any shortcomings by always addressing me as der gnädige Herr.
The day was hot, so it took us three-quarters of an hour on foot, along the valley of the Thaya, to reach the base of the bluff where the Eisleithen are situated, at an altitude of about four hundred meters. The hillside is covered with patches of scrubby forest; and towards the summit, the entire mass of the hill is honey-combed with cracks and the rocks are much broken up. After about ten minutes’ ascent up a little path, we came to small holes, from each of which a current of cool air poured out; these holes seemed fairly horizontal, and the temperatures were high enough to prove that there was no ice within. A little further on, we came to a hole or tiny cave among a pile of rocks, where there was a painted sign: Eisgrube. It went down from the mouth, and I put my hand well in, but, beyond the length of my arm, I could neither see nor measure its shape or depth. The air felt cold, but was nowhere near freezing point; nor was it possible to determine whether there was a draught: it may or may not be a wind cave. Not far from this, there were two gullies, each terminating in a small cave. The first gully was planned somewhat like certain traps for wild animals, that is, it narrowed gradually from the entrance, then became covered over; and then dwindled, after some four meters more, into a small descending hole, the end of which we could not reach. But we got in far enough, to come to large chunks or slabs of ice plastered about on the floor and sides. In this cave, which was sheltered against sun and wind, the air, as tested by the smoke of a cigar, was motionless, and the cave seemed unconnected with any air current. The second gully terminated in a somewhat larger cave, whose floor was well below the entrance; no ice was visible, however, although the air was still and the temperature low. This cave may or may not be a glacière; but surely it is not a cold current cave.
These Frainer Eisleithen certainly offer an interesting field to anyone studying subterranean ice, from the fact that there are, in the same rocks, caves without apparent draughts in summer and containing ice, and caves with distinct draughts and no ice. The problem seems more intricate than is usually the case, but the solution is simply that the two classes of caves happen to be found together.
THE EISHÖHLE BEI ROTH.
The Eifel is one of the bleakest districts of Central Europe, and to one entering it from the vineyards and the well-inhabited basin of the Rhine, the contrast is impressive. The railroad rises gradually to a land of comparatively desert appearance, with rocks and trees on the heights and a sparse cultivation in the valleys. But, if the country is unattractive to the agriculturist, it is interesting to the geologist, on account of the great number of extinct volcanoes. Almost in the centre of the Eifel is the little town of Gerollstein, famed for the Gerollsteiner Sprudel, which gives forth an effervescence undreamed of by anyone, who has not visited the birth place of some of these German table waters.
About an hour’s walk from Gerollstein, on the side of a small hill, is situated the little Eishöhle bei Roth, named after a neighboring village. I went to this place, on the 25th of June, 1896, with a young boy as guide. The cave is sheltered from the wind by a wood around it, among which are many large trees. It is at the base of a wall of piled up lava, or at least volcanic, rocks which form a sort of cauldron. The entrance is a small tunnel some five meters long, which goes straight down at an angle of about twenty-five degrees and then turns sharply to the left. At the turn, the cave may be perhaps one meter in height. We did not go beyond this spot, where the air was icy and the temperature sub-normal, as the tunnel was blocked up by a large boulder, which had evidently recently fallen from the rocks in front. There was no ice, as far as we went, and the boy said it began three or four meters further in. He told me that there was no ice in the cavern in winter, but admitted that he had not entered it at that season, so that was hearsay. He had heard also that the ice was sometimes taken out for sick people, but otherwise it was not used.