The sound of the water between the chasm walls was now a thunder in his ears.

He could not have heard a rifle-shot or a scream a hundred yards away.

The trail he was following had continually grown narrower.

It seemed to end a little ahead of him, and the fear that he had come the wrong way after all filled him with dread.

He came to the face of the mountain wall, and then, to his left, he saw a crack that was no wider than a man's body.