As to their speech--the Holy Mountain itself would explain. And yes, truly, this was the center of the world, or the sun above them was. The central sun did not attract, but instead repelled all matter from it--all things but one, the sun-stone, of which Gor would speak later. Rawson pounced upon that and demanded corroboration. "All the power of earth tends to draw every object to its center, yet we're here on an inner surface. We're walking actually head down. And our bodies, every stone, every particle of matter, ought by well-known laws to fall into that flaming center. But we don't! That proves your point--proves a counter gravitation. Then there must be a neutral zone. A place where this upward thrust is exactly equalled by gravity's downward pull. "The zone of fire," said Gor. "You passed through it. Did you not see?" "Saw it and felt it!" Rawson's mind leaped immediately to the next question. "And we must have come through it at, surely, a thousand miles an hour. What drove us? That shell must have gone in from here. I can understand its falling one way, but not two. We should have come to rest in that very spot--and we'd have lasted about half a second if we had." "Oro and Grah," said Gor. "Oro, the sun-stone, and Grah, the stone-that-loves-the-dark. But they are not stones, neither are they metal. We find them deep in the ground, clinging to the caves. A fine powder, both of them." "Still I don't get it," said Rawson. "You drive that shell in from here, and then you drive it back again." "That, too, I will explain later. It is simple; even the Dwellers in the Dark--those whom you call the mole-men--have Oro and Grah to serve them." * * * * * Gor launched into a long account of their tribal legends, of that time in the long ago when an angry sun god had driven his children inside the earth; of how Gor, and the son of Gor, and his son's sons tried always to return. Rawson was listening only subconsciously. They were circling the white mountain, ascending its lower slope. Now he could see beyond it as far as the land extended, and he was startled to find this distance so short. They were on an island, ten miles or so in length, and beyond it was the sea; he must ask Gor about that. "It is all that is left," said Gor, when Rawson interrupted his narrative. "Once the land was great and the sea small--this also in the long ago--but always it has risen. The air we breathe and the water in the sea come from the central sun. The air rushes out, as you know; the water has no place to retreat." Again he took up his tale, but Rawson's eyes were following the upward curve of that sea. They, seemed to be in the bottom of a great bowl; he was trying to estimate, trying to gage distance.