hundred feet in height, a great volume of water poured its roaring
current into a boiling pool below. The cliffs shot up sheer on all
sides and were covered at the bottom with luxuriant green growth
like seaweed, while higher up, ferns, as big as rose-bushes at home,
and trees of a hundred varieties clung wherever they could find a
root-hold. As the party arrived at the top of the ravine and gazed
down, the uproar of the water was so terrific as to render any
speech inaudible. M. Desplaines, who led the party, pointed to a
hole in the rocks and a second later vanished into it.

At first, consternation seized on the boys who thought that an
accident had happened, but seeing not hearing Professor Wiseman's
reassuring laugh and noticing him plunge after M. Desplaines, the
boys rightly concluded that the aperture was a subterranean entrance
to the foot of the falls. And so it proved. A steep flight of
steps was cut in a deep cleft of the cliff down to the water's edge.
A few minutes after they had begun the descent, the little party stood
on the brink of the whirling pool into which the mighty falls roared
their thousands of tons of water. Following M. Desplaines, they
advanced down the stream to a point where a bend shut off like a
rock curtain the deafening uproar of the cascade. Here a canoe lay
moored and Frank and Harry stepped into it and shoved off. Their
lines and other equipment they had in their pockets.

As they shoved out M. Desplaines shouted something that they did not
catch and pointed down the stream. How near the fact that they
could not hear his words was to come to costing them their lives
neither of the boys guessed.