cutting out that channel, hurling down mighty boulders
and stream-driven shingle upon the living rock; but it was, it seemed
to him, within man's power to alter it in a few arduous months. He
sat very still, astonished at the daring of his own conception, until
Wheeler strolled up to him.

"How much does the river drop at the fall?" he asked.

"About eight feet in the fall itself," answered Wheeler. "Seems to me
it falls much more in the rush above. Still, I can't say I noticed it
particularly--I had something else to think about."

"It's a short rapid," remarked Nasmyth reflectively. "There is, no
doubt, a great deal of the hardest kind of rock under it, which is, in
one or two respects, unfortunate. I suppose you don't know very much
about geology?"

"I don't," confessed the pulp-miller. "Machines are my specialty."

"Well," said Nasmyth, "I'm afraid I don't either, and I believe one or
two of these canyons have puzzled wiser folks than I. You see, the
general notion is that the rivers made them, but it doesn't seem quite
reasonable to imagine a river tilting at a solid range and splitting
it through the middle. In fact, it seems to me that some of the canyons
were there already, and the rivers just ran into them. One or two
Indians have come down from the valley close to the fall, and they
told me the river was quite deep there. The rock just holds it up at
the fall. It's a natural dam--a dyke, I think they call it."

"I don't quite understand what all this is leading to," observed
Wheeler.

Nasmyth laughed, though there was, as his companion noticed, a curious
look in his eyes. "I'll try to make it clearer when we get into the
valley. We're going there to-morrow."

It was almost dark now, and they went back together to the little fire
that burned redly among the spruces in the ravine. There Mattawa and
Gordon had a simple supper ready. The others stretched themselves
out, rolled in their blankets, soon after they had eaten, but Nasmyth
lay propped up on one elbow, wide awake, listening to the roar of
water until well into the night. The stream drowned the faint rustling
of the spruces in a great dominant note, and he set his lips as he
recognized its depth of tone and volume. He had once more determined
to pit all his strength of mind and body against the river. Still, he
went to sleep at last, and awakening some time after it was dawn on
the heights above, roused his comrades. When breakfast was over he