The air grew hotter. So hot at last that Odin had to pause more often and rest upon the sand. But it too was hot, as though it had never known anything but this one temperature.

Stumbling along, his nostrils and chest burning, and something thumping in his ears, he finally fell to his knees. Jack Odin lay there for a long time. But the floor of the cavern still led downward. So, with nothing else left in his mind, he got to his knees and crawled on.

That last determination saved him. A cool breath of air struck him in the face. He toiled downward and was soon in a wider cavern that was so cold that he was shivering. He rested again and then went on. The cold grew worse.

Odin came to a tunnel of ice. The faint smell of ammonia set him to coughing. It was nearly as uncomfortable here as the heat had been a few hours before. But he kept on. Finally, there was no ice left on the walls about him. The air grew warmer.

Soon the walls opened out until he could scarcely see them with his flashlight. Playing it upward he could only get a faint reflection from the stalactites hundreds of feet away.

At length Odin came to a vast room where his light could reach neither walls nor ceiling. But in the center of it was a tiny pool, rimmed by white sand and a shell-like lip of limestone. He got to his knees and tested the water. It was clean—but old and old and old. Filling his canteen, he opened his knapsack and prepared a hearty meal. He was dog-tired but before he slept he walked around the little pool. He had heard of fish being found in underground caverns—or even the fossils of things that had once been there. But here Odin found no sign of life. Nothing except traces of the vast underground river that must have once swept through here long ago.

It was a desolate feeling to stand there with his beam of light pushing the dark away. Alone in a place which apparently had never known the beat of life before. And then Odin saw it—

A footprint. A small footprint which must have been made by someone who wore moccasins or sandals. He recognized it at once. He had seen hundreds of those footprints!

A Neebling had been there. How long before he did not know. But, certainly, Odin’s theory had been right. The cavern led the way to Opal. Jack Odin was not sure how many times he ate and slept as he toiled his way downward. The long dead river had carved cunningly and beautifully upon the walls of the tunnel. And the dripping waters of centuries had fashioned pedestals, carvings, and statues that were beautiful indeed. Ordinarily he would have been interested in these, for Jack Odin was a man who loved beautiful things, but now he had but one idea: To go on.

Occasionally he found more footprints. But always near the scattered pools. The dwarfs must have kept against the walls and come out upon the sand only to quench their thirst. He wondered about that. And a possible answer came to him. They had been there without a light—feeling their way, almost—although he knew that they could see in the dark to a certain extent. He wondered at their courage. Here, with two lights, the staring darkness and the silent empty spaces were making him shaky.