As they glided gently along, the irregular walls of the aisle came nearer to them out of the darkness with a nearness that was sinister and hateful. It was as though they crept close with the full intention of crushing the craft and grinding the men to death between their ponderous fangs and molars. They seemed avengers of the echoes outraged by the laughter. The luminous shaft still shone; but as they came nearer, the light grew whiter and less like flame. The red glare of the torch seemed to overcome it. The men watched it with starting eyes. The walls of the cave came closer out of the darkness, and the roof lowered. By this time Phelan had lost all his fears, and was as curious as the others to know what the light was. All at once he cried out--"Ease!" Both men stopped rowing. The sound of the oars ceased, and the noise of the ripple from the oars. All listened intently. A hissing sound could be distinctly heard--a loud hissing sound which they had not noticed before, because, no doubt, of the gradualness of their approach and the noises made by the rowers. "It's water--falling water. But, in the name of all the saints, where is it falling from, and how can we see it in the darkness? Give way, Tim." The cave grew narrower still, and now there was barely room for the shortened oars. The sides of it came closer, the roof lowered until it was no more than an arm's length above the heads of the standing men. The bright patch grew higher and broader. The torch still burned. A dull whiteness shone on the rocks. The luminous space now looked like a faintly-lighted sheet of glass. The hissing sound of the water had gathered intensity. "I don't know what's beyond, but I'll risk going through if you are willing," cried Phelan, who was now in a state of almost frenzy from suppressed excitement. "Go on--go on!" shouted O'Brien, who found it difficult to keep from jumping overboard. "Go on!" repeated Alfred, who, too, was now standing up. "Give way with a will!" shouted Phelan; and in a minute the boat shot through a thick sheet of foam and falling water, and glided into a placid pool. For a moment the men were blinded by the foam and water, and could see nothing. They rubbed their eyes, looked up obliquely, and were blinded once again. The mid-day sun flamed above their heads at the end of a stupendous tube. An indescribable cry arose. Then all was still. A crow flew between them and the sun. All bent their heads and crouched low as though instant death was rushing down upon them. The crow went by harmlessly. "Do you know where we are?" asked Phelan, in the voice of an awestruck child. "No." "At the bottom of the shaft of the old mine. It slants to the southward, and that's the sun!" They looked around: some wreckage floated on one side of the boat. "The planks that covered the mouth of the shaft. They must have fallen in." Something that was not a plank floated on the other side of the boat. It was the body of Fahey!