"I saw you," he said. "And the sky. It was like looking up out of water. I looked down and around. A little below me was something like a floor of pale green mist. I couldn't see through it. It's warm in there, good and plenty warm, and it smells like trees and flowers. That's all I managed to grasp before I went goofy. Oh, yes, this rock fall keeps right on going down. Maybe we can get to the bottom of it—if we don't laugh ourselves off. I'm going right out and sit in that mirage up to my neck—my God, Leif, I'm freezing!"
I looked at him with concern. His lips were blue, his teeth chattering. The transition from the warmth to the bitter cold was having its effect, and a dangerous one.
"All right," I said, rising. "I'll go first. Breathe slowly, take deep, long breaths as slowly as you can, and breathe out just as slowly. You'll soon get used to it. Come on."
I slung the remaining pack over my back, craw–fished over the side of the stone, felt solid rock under my feet, and drew myself down within the mirage.
It was warm enough; almost as warm as the steam–room of a Turkish bath. I looked up and saw the sky above me like a circle of blue, misty at its edges. Then I saw Jim's legs dropping down toward me, his body bent back from them at an impossible angle. I was seeing him, in fact, about as a fish does an angler wading in its pool. His body seemed to telescope and he was squatting beside me.
"God, but this feels good!"
"Don't talk," I told him. "Just sit here and practise that slow breathing. Watch me."
We sat there, silently, for all of half an hour. No sound broke the stillness around us. It smelled of the jungle, of fast–growing vigorous green life, and green life falling as swiftly into decay; and there were elusive, alien fragrances. All I could see was the circle of blue sky above, and perhaps a hundred feet below us the pale green mist of which Jim had spoken. It was like a level floor of cloud, impenetrable to the vision. The rock–fall entered it and was lost to sight. I felt no discomfort, but both of us were dripping with sweat. I watched with satisfaction Jim's deep, unhurried breathing.
"Having any trouble?" I asked at last.
"Not much. Now and then I have to put the pedal down. But I think I'm getting the trick."
"All right," I said. "Soon we'll be moving. I don't believe it will get any worse as we go down."
"You talk like an old–timer. What's your idea of this place anyway, Leif?"
"Simple enough. Although the combination hasn't a chance in millions to be duplicated. Here is a wide, deep valley entirely hemmed in by precipitous cliffs. It is, in effect, a pit. The mountains enclosing it are seamed with glaciers and ice streams and there is a constant flow of cold air into this pit, even in summer. There is probably volcanic activity close beneath the valley's floor, boiling springs and the like. It may be a miniature of the Valley of Ten Thousand Smokes over to the west. All this produces an excess of carbon–dioxide. There is most probably a lush vegetation which adds to the product. What we are going into is likely to be a little left–over fragment of the Carboniferous Age—about ten million years out of its time. The warm, heavy air fills the pit until it reaches the layer of cold air we've just come from. The mirage is produced where the two meet, by approximately the same causes which produce every mirage. How long it's been this way, God alone knows. Parts of Alaska never had a Glacial Age—the ice for some reason or another didn't cover them. When what is New York was under a thousand feet of ice, the Yukon Flats were an oasis filled with all sorts of animal and plant life. If this valley existed then, we're due to see some strange survivals. If it's comparatively recent, we'll probably run across some equally interesting adaptations. That's about all, except there must be an outlet of some kind somewhere at about this level, otherwise the warm air would fill the whole valley to the top, as gas does a tank. Let's be going."
"I begin to hope we find the guns," said Jim, thoughtfully.
"As you pointed out, they'd be no good against Khalk'ru—what, who, if and where he is," I said. "But they'd be handy against his attendant devils. Keep an eye out for them—I mean the guns."
We started down the rock–fall, toward the floor of green mist. The going was not very difficult. We reached the mist without having seen anything of rifles or packs. The mist looked like a heavy fog. We entered it, and that was precisely what it was. It closed around us, thick and warm. The rocks were reeking wet and slippery, and we had to feel for every foot of the way. Twice I thought our numbers were up. How deep that mist was, I could not tell, perhaps two or three hundred feet—a condensation brought about by the peculiar atmospheric conditions that produced the mirage.
The mist began to lighten. It maintained its curious green tint, but I had the idea that this was due to reflection from below. Suddenly it thinned to nothing. We came out of it upon a breast where the falling rocks had met some obstruction and had piled up into a barrier about thrice my height. We climbed that barrier.
We looked upon the valley beneath the mirage.
It lay a full thousand feet beneath us. It was filled with pale green light like that in a deep forest glade. That light was both lucent and vaporous, lucent where we stood, but hiding the distance with misty curtains of pallid emerald. To the north and on each side as far as I could see, and melting into the vaporous emerald curtains, was a vast carpet of trees. Their breath came pulsing up to me, jungle–strong, laden with the unfamiliar fragrances. At left and right, the black cliffs fell sheer to the forest edge.
"Listen!" Jim caught my arm.
At first only a faint tapping, then louder and louder, we heard from far away the beating of drums, scores of drums, in a strange staccato rhythm—shrill, mocking, jeering! But they were no drums of Khalk'ru! In them was nothing of that dreadful trampling of racing feet upon a hollow world.
They ceased. As though in answer, and from an entirely different direction, there was a fanfarade of trumpets, menacing, warlike. If brazen notes could curse, these did. Again the drums broke forth, still mocking, taunting, defiant.
"Little drums," Jim was whispering. "Drums of—" He dropped down from the rocks, and I followed. The barrier led to the east, dipping steadily downward. We followed its base. It stood like a great wall between us and the valley, barring our vision. We heard the drums no more. We descended five hundred feet at least before the barrier ended. At its end was another rock slide like that down which the rifles and pack had fallen.
We stood studying it. It descended at an angle of about forty–five degrees, and while not so smooth as the other, it had few enough foot–holds.
The air had steadily grown warmer. It was not an uncomfortable heat; there was a queer tingling life about it, an exhalation of the crowding forest or of the valley itself, I thought. It gave me a feeling of rampant, reckless life, a heady exaltation. The pack had grown tiresome. If we were to negotiate the slide, and there seemed nothing else to do, I couldn't very well carry it. I unslung it.
"Letter of introduction" I said, and sent it slithering down the rock.
"Breathe deep and slow, you poor ass," said Jim, and laughed.
His eyes were bright; he looked happy, like a man from whom some burden of fear and doubt has fallen. He looked, in fact, as I had felt when I had taken up that challenge of the unknown not so long before. And I wondered.
The slithering pack gave a little leap, and dropped completely out of sight. Evidently the slide did not go all the way to the valley floor, or, if so, it continued at a sharper angle at the point of the pack's disappearance.