The scene before me was indescribably awe-inspiring. The vast dimensions of this mighty space beneath Earth's crust were enough to stagger the mind. This was no mere cavern, but an enormous hollow such as many have believed was left under the planet's surface by the hurling forth of the Moon.
The rocky roof was a mile above the floor. Our disk had halted just where the vertical pit entered the roof, close beside one rock wall of the great space. From the spot where Thor and I gazed, the subterranean world stretched off out of sight, to right and left and ahead.
Many miles away from us there shone a dazzling thing that dominated the whole vast, blazing fane with its brilliance. It was a colossal fountain of cold, white fire that gushed from a chasm in the floor. Hundreds of feet into the air it rose, falling back on itself in continual blinding spray. From it shot beams and banners of blinding light and force, a shaking, shuddering radiance.
All across the underworld rose similar but smaller geysers of white fire, gushing jets of radiance like that mighty distant one. Wherever the eye turned, it encountered such fiery fountains. They filled the underworld with a roaring that was deafening, and a terrific green-white radiance.
"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.
Hastily, fully awakening to the peril of remaining long in this hell of fierce radiation, I helped Thor pick up the leaden crucible we had brought. We stepped from the disk to the landing, and started down the stair. It was hard walking in our stiff lead garments, and with the weight of the crucible to carry. Moreover, the stair was without any protective rail, and perilously narrow.
Chapter XVI
The Flame Creatures
When we reached the floor of the underworld, we stood within a hundred yards of one of the many geysers of atomic fire. Though half-blinded by its brilliance, I was able to see that it jetted from a mass of radioactive mineral whose normally slow disintegration had been tremendously accelerated. It had been kindled to this faster disintegration, I knew, by the flame that had fallen from the central fountain.
"We shall have to find a radioactive deposit unkindled as yet," I called to Thor.
He nodded his lead-cowled head vigorously.
"Let us try this direction, Jarl Keith."
We stumbled with the crucible between the geysers of atomic flame. Sometimes we were forced to go so near one of the jets that its inconceivable radiation seemed bound to penetrate our suits. Dazzled even through my lead-glass eyeholes by the raging brilliance, every fiber of my body tingling, I searched desperately for such a deposit as we required. If our suits should be penetrated, we would die horrible deaths.
"This way, Thor!" I called suddenly as I found a mass of mineral in a niche in the broken rock floor.
It was glowing with a soft light that seemed feeble in comparison with the flaming atomic fountains. I recognized it as an isotope of radium itself, never found in a natural state in my own upper world.
"There's more than enough of the stuff here, if we can dig it out!" I exclaimed. "We'll have to use our staffs."
The iron pikes we carried were ill-adapted to digging out the hard, glowing mineral. But we set to work, prying out chunks of the stuff and tossing them into the crucible. As I straightened once, panting for breath, I glimpsed an amazing sight in the middle distance.
Around one of the geysers were circling and flitting a dozen things that looked like swirling spheres of flame, with coiling, brilliant tentacles of light.
"Those things look as though they were alive!" I yelled in horror.
Thor straightened to see.
"Flame-children!" he exclaimed, his muffled voice suddenly anxious. He turned to me hastily. "They are alive, in a way. But it is not life like ours. They are creatures evolved somehow from the flaming radiation of this underworld of atomic fires. We believe they consist of force currents that cohere in a permanent pattern, which possess powers of movement and perhaps dim intelligence. We don't know much about them, for they've evolved here since the Aesir left poor Muspelheim."
"They look beautiful, like flame-winged birds of light," I said, staring in awe and fascination.
"They're dangerous, Jarl Keith — pure concentrated atomic energy!" warned the Hammerer. "We must be gone before they find us."
I redoubled my toil of helping to dig out the radioactive chunks. We had the crucible half-full of the precious mineral when I felt a terrific shock of force against my back. I whirled around, uttered a cry. One of the dazzling flame-children was poised behind me, had just touched my suit. The mere touch of the weird creature had burned almost through the thick lead!
"We've got to get out!" Thor bellowed. "The thing has almost pierced your suit. The radiation will penetrate it in a few minutes, and you'll die horribly."
"But we haven't all the radioactive matter that Odin will need," I protested.
"We have most of it. If you perish here, we'll never get even this much back to him. Quick, up the stair to the disk!"
He grabbed the crucible's handle. Reluctantly I took the other handle and started with him toward the stair. As we hastened with our heavy load between the roaring geysers of atomic fire, I looked back. The one of the flame-children that had touched me experimentally was now joining several other dazzling creatures like itself, and drifting after us.
Hastily we started up the stair. With some relief, I saw that the flame-children did not follow us, but drifted on and started circling and flitting around another of the fire fountains. Apparently the dim intelligence of the creatures, if indeed they possessed any, had lost interest in us.
Panting and exhausted, we reached the landing and set the crucible down on the floating disk. Thor hastily adjusted the controls to make up for the increased weight on it. As he crouched down, preparatory to starting up the shaft, I noticed something.
"Thor, what is that door up there, high in the roof?" He turned his gaze to follow my pointing finger. The door looked like a massive sliding sheet of dull metal, set in the roof of the underworld some distance from us. There was a shielded mechanism of some kind set in the rock by the door, obviously controlling it.