"Can your people ever have lived here?" I cried shakenly to Thor, as I gazed stupedfiedly from the floating disk.
"Aye, Jarl Keith. Centuries ago we dwelt here, where we had evolved and lived for ages. But then this was a fair world. There was no fire except that one great atomic fountain which you see far away. It was smaller then than now, yet its radiations were sufficient to keep this whole underworld warm and habitable.
"Then accursed Loki tampered with our fire fountain. He sought to stimulate it to greater activity, so that its increased radiations would make us almost immortal. He so disturbed and aroused the fountain that its fires shot up and fell here and there, all across the underworld. Eventually it set masses of radioactive matter everywhere to blazing up in atomic flame themselves.
"Thus we had to flee from disaster-smitten Muspelheim. We managed to pierce the pit up to the upper world, and clambered up it by a toilsome stair carved in its side. And since then Muspelheim has been a world of fire, forsaken by men."
I was so stunned by the awesome spectacle that I had almost forgotten our mission here. But Thor recalled it to me.
"We must not stay here long, Jarl Keith!" he warned. "The awful radiation here would slay us if it penetrated our leaden suits."
I glanced down.
"There must be plenty of radioactive matter here, all right," I said. "But how do we get down to the floor?"
"By this stair. It's part of the ancient way by which my people escaped to the upper world."
I saw now that the disk had halted beside the landing of a stair which was chiseled from the rock wall of the underworld. The stair climbed up from the floor and disappeared into the pit-shaft by which we had descended.