The air was bitterly cold as we set out: it was twenty-five below and a sharp wind was blowing. Only our toiling at the sledge kept us warm.

We covered eighteen miles that day, and made a good camp in the lee of a bare stone ridge.

That night there was a slight fall of snow. When we went on it was nearly thirty-five degrees below zero. The layer of fresh snow concealed irregularities in the ice, making our pulling very hard.

After an exhausting day we had made hardly fifteen miles.

On the following day the sky was covered with gray clouds, and a bitterly cold wind blew. We should have remained in the tent, but the shortage of food made it imperative that we keep moving. We felt immensely better after a reckless, generous fill of hot pemmican stew; but the next morning my feet were so painful from frost-bite that I could hardly get on my fur boots.

Walking was very painful to me that day, but we made a good distance, having come to smoother ice. Ray was very kind in caring for me. I became discouraged about going on at all: it was very painful, and I knew there was no hope of getting out. I tried to get some of our morphine tablets, but Ray had them, and refused to be convinced that he ought to go on without me.

On the next march we came in sight of the luminous mountain, which cheered me considerably. It was a curious thing, indeed. A straight-sided cone of light it was, rather steeper than the average volcano. Its point was sharp, its sides smooth as if cut with a mammoth plane. And it shone with a pure white light, with a steady and unchanging milky radiance. It rose out of the black and dull yellow of the ice wilderness like a white finger of hope.

The next morning it was a little warmer. Ray had been caring for my feet very attentively, but it took me nearly two hours to get on my footgear. Again I tried to get him to leave me, but he refused.

We arrived at the base of the shining mountain in three more marches.

On the last night the fuel for the primus was all gone, having been used up during the very cold weather, and we were unable to melt water to drink. We munched the last of our pemmican dry.

A few minutes after we had started on the last morning, Ray stopped suddenly.

"Look at that!" he cried.

I saw what he had seen--the wreck of an airplane, the wings crumpled up and blackened with fire. We limped up to it.

"A Harley biplane!" Ray exclaimed. "That is Major Meriden's ship! And look at that wing! It looks like it's been in an electric furnace!"

I examined the metal wing; saw that it had been blackened with heat.

The metal was fused and twisted.

"I've seen a good many wrecks, Jim. I've seen planes that burned as they fell. But nothing like that. The fuselage and engines were not even afire. Jim, something struck out from that shining mountain and brought them down!"

"Are they--" I began.

Ray was poking about in the snow in the c.o.c.kpits.

"No. Not here. Probably would have been better for them if they had been killed in the plane. Quick and merciful."

He examined the engines and propellers.

"No. Seems to be nothing wrong. Something struck them down!"

Soon we went on.

The shining mountain rose before us like a great cone of fire. It must have been three thousand feet high, and about that in diameter at the bottom. Its walls were as smooth and straight as though turned from milky rock crystal in a gigantic lathe. It shone with a steady, brilliantly white radiance.

"That's no natural hill!" Ray grunted beside me as we limped on.

We were less than a mile from the foot of the cone of fire. Soon we observed another remarkable thing about it. It seemed that a straight band of silvery metal rose from the snow about its foot.

"Has it a wall around it?" I exclaimed.

"Evidently," said Ray. "Looks as if it's built on a round metal platform. But by whom? When? Why?"

We approached the curious wall. It was of a white metal, apparently aluminum, or a silvery alloy of that metal. In places it was twenty-five feet high, but more usually the snow and ice was banked high against it. The smooth white wall of the gleaming mountain stood several hundred yards back from the wall.

"Let's have a look over it." Ray suggested. "We can get up on that hummock, against it. You know, this place must have been built by men!"

We clambered up over the ice, as he suggested, until our heads came above the top of the wall.

"A lake of fire!" cried Ray.

Indeed, a lake of liquid fire lay before us. The white aluminum wall was hardly a foot thick. It formed a great circular tank, nearly a mile across, with the cone of white fire rising in the center. And the tank was filled, to within a foot of the top, with shimmeringly brilliant white fluid, bright and luminous as the cone--liquid light!

Ray dipped a hand into it. The hand came up with fingers of fire, radiant, gleaming, with shining drops falling from them. With a spasmodic effort, he flung off the luminous drops, rubbed his hand on his garments, and got it back into its fur mitten.

"Gee, it's cold!" he muttered. "Freeze the horns off a bra.s.s billy-goat!"

"Cold light!" I exclaimed. "What wouldn't a bottle of that stuff be worth to a chemist back in the States!"

"That cone must be a factory to make the stuff." Ray suggested, hugging his hand. "They might pump the liquid up to the top, and then let it trickle down over the sides: that would explain why the cone is so bright. The stuff might absorb sunlight, like barium sulphide. And there could be chemical action with the air, under the actinic rays."

"Well, if somebody's making cold light, where does he use it?"

"I'd like to find out, and strike him for a hot meal," Ray said, grinning. "It's too cold to live on top of the ground around here.

They must run it down in a cave."

"Then let's find the hole."

"You know it's possible we won't be welcome. This mountain of light may be connected with the vanishing of all the aviators. We'd better take along the rifle."

We set off around just outside the white metal wall. The snow and ice was irregularly banked against it, but the wall itself was smooth and unbroken. We had limped along for some two miles, or more than halfway around the amazing lake of light. I had begun to doubt that we would find anything.

Then we came to a square metal tower, ten feet on a side, that rose just outside the silvery wall, to a level with its top. The ice was low here; the tower rose twenty feet above its unequal surface. We found metal f.l.a.n.g.es riveted to its side, like the steps of a ladder.

They were most inconveniently placed, nearly four feet apart; but we were able to climb them, and to look down the shaft.

It was a straight-sided pit, evidently some hundreds of feet deep. We could see a tiny square of light at the bottom, very far away. The f.l.a.n.g.es ran down the side forming the rungs of a ladder that gave access to whatever lay at the bottom.

Without hesitation, Ray climbed over the side and started down. I followed him, feeling a great relief in getting out of the freezing wind. Ray had the rifle and ammunition strapped to his back, along with a few other articles; and I had a small pack. We had abandoned the sledge, with the useless stove and the most of our instruments.

Our food was all gone.

The metal f.l.a.n.g.es were fully four feet apart, and it was not easy to scramble down from one to another; certainly not easy for one who was cold, hungry, thirsty, worn out with a week of exhausting marches, and suffering the torture of frozen feet.