Adown this a stream trickles towards the end of summer, but plunges
madly and with a frightful roar in winter and spring. The steep sides
of the narrow ravine are densely wooded, and the light is very dim at
the bottom when the sun is not overhead. I made my first attempt to
descend the dark passage in the early summer, but there was too much
water, and I was soon obliged to retreat. One afternoon in October I
returned with a companion, and we took with us a rope and plenty of
candles. We carried the rope in view of possible difficulties in the
shape of rocks inside the cavern, for it should be borne in mind that
in _gouffres_ of this character the stream frequently descends by a
series of cascades. The weather was very sultry, and the sky towards
the west was of a slaty blue. A fierce storm was threatening, but we
paid no attention to it--a mistake which others bent on exploring
caverns where streams still flow should be warned against. There is
probably no force in nature more terrible, or which makes a man's
helplessness more miserably felt, than water suddenly rushing towards
him when he is underground.

The sun was still shining, however, when we reached the Gouffre de
Révaillon and descended into the ravine over roots of trees coiling
upon the moss like snakes, some arching upward as if about to spring
at the throat of those who disturbed the elfish solitude. At our
coming there rose from the great rock such a multitude of jackdaws
that for some seconds they darkened the air. With harsh screams the
birds soared higher and higher above their fortress, which they had
possessed for ages in perfect security. We reached the bed of the
stream, where scattered threads of water tinkled as they fell over
huge blocks into little pools below, and then went whispering on their
way towards the darkness. At the botton of a long slant of greenish
slimy stone, patched here and there with moss, I stopped a few