exceedingly fatiguing, and we hailed with delight a sudden circular opening in the roof which enabled us to stand upright.  This delight was immensely increased when our candles showed us that the walls of this vertical opening were profusely decorated with the most lovely forms of ice.  The first that we came under passed up out of sight; and in this, two solid cascades of ice hung down, high overhead, apparently broken off short, or at any rate ending very abruptly:  the others did not pass so far into the roof, and formed domes of very regular shape.  In all three, the details of the ice-decoration were most lovely, and the effect produced by the whole situation was very curious; for we stood with our legs exposed to the alternating cold currents, the remaining part of our bodies being imbedded as it were in the roof; while the candles in our hands brought out the crystal ornaments of the sides, flashing fitfully all round us and overhead, when one or other of us moved a light, as if we had been surrounded by diamonds of every possible size and setting.  One of the domes was so small, that we were obliged to stand up by turn to examine its beauties; but in the others we all stood together.  On every side were branching clusters of ice in the form of club-mosses, with here and there varicose veins of clear ice, and pinnacles of the prismatic structure, with limpid crockets and finials.  The pipes of ice which formed a network on the walls were in some cases so exquisitely clear, that we could not be sure of their existence without touching them; and in other cases a sheet 4 or 6 inches thick was found to be no obstruction to our view of the rock on which it was formed.  In one of the domes we had only one candle, and the bearer of this after a time contrived to let it fall, leaving us standing with our heads in perfect darkness; while the indistinct light which strayed about our feet showed faintly a circle of icicles, hanging from the lower part of the dome, the fringe, as it were, of our rocky petticoats.

In one of the lower parts of the cave, where darkness prevailed, and locomotion was only possible on the lowest reptile principles, M. announced that she could see clear through the ice-floor, as if there were nothing between her and the rock below.  I ventured to doubt this, for there was an air of immense thickness about the whole ice; and as soon as A. and I had succeeded in grovelling across the intervening space, and converged upon her, we found that the appearance she had observed was due to a most perfect reflection of the roof, as shown by the candles we carried, which may give some idea of the character of the ice.  We did not care to study this effect for any very prolonged time, inasmuch as we were obliged meanwhile to stow away the length of our legs on a part of the ice which was thinly covered with water,—­one result of its proximity to the arch communicating with the smallest pit.