Guinness felt with his hands a moment and nodded slowly. "Yes," he said.
"It's coming from this way!" Sue said excitedly, pointing into the darkness on one side of the cavern. "And it goes up the hole we made in the ceiling!"
Phil turned eagerly to the old inventor. "It must come from somewhere," he said, "and that somewhere may take us toward the surface. Let's follow it!"
"We might as well," the other agreed wearily. His was the tone of a man who has only a certain time to live.
But Phil was more eager. "While there's life, there's hope," he said cheerfully. "Come on, Sue, Professor!" And he led the way forward toward the dim, distorted rock shapes in the distance.
he roof and sides of the cavern angled down into a rough, tunnel-like opening, from which the draft swept. It was a heavy air, weighted with the smell of moist earth and lifeless water and a nameless, flat, stale gas. They slowly made their way through the impeding stalagmites, surrounded by a dark blur of shadows, the ghostly phosphorescent light illuminating well only the few rods around them. Utter silence brooded over the tunnel.
Phil paused when they had gone about seventy-five feet. "I left that rope behind," he said, "and we may need it. I'll return and get it, and you both wait right here." With the words he turned and went back into the shadows.
He went as fast as he could, not liking to leave the other two alone. But when he had retrieved the rope and tied it to his waist, he permitted himself a last look up as he passed under the hole in the ceiling—and what he saw there tensed every muscle in his body, and made his heart beat like mad. Again there was a tiny spot of orange in the blackness above!