I almost let go the sledge-bar to go look for him. It was pure luck that I did not. I held on, while I stared stupidly about for him, and so I saw the lip of the crevasse, made visible by the shifting and dropping of another section of the broken snow-bridge. He had gone right down feet-first, and nothing kept the sledge from following him but my weight, which held the rear third of the runners still on solid ice. It kept tipping a little farther nose-downward, pulled by his weight as he hung in harness in the pit.

I brought my weight down on the rear-bar and pulled and rocked and levered the sledge back away from the edge of the crevasse. It did not come easy. But I threw my weight hard on the bar and tugged until it began grudgingly to move, and then slid abruptly right away from the crevasse. Estraven had got his hands onto the edge, and his weight now aided me. Scrambling, dragged by the harness, he came up over the edge and collapsed face down on the ice.

I knelt by him trying to unbuckle his harness, alarmed by the way he sprawled there, passive except for the great gasping rise and fall of his chest. His lips were cyanotic, one side of his face was bruised and scraped.

He sat up unsteadily and said in a whistling whisper, "Blue—all blue— Towers in the depths—"

"What?"

"In the crevasse. All blue—full of light."

"Are you all right?"

He started rebuckling his harness.

"You go ahead—on the rope—with the stick," he gasped. "Pick the route."

For hours one of us hauled while the other guided, mincing along like a cat on eggshells, sounding every step in advance with the stick. In the white weather one could not see a crevasse until one could look down into it—a little late, for the edges overhung, and were not always solid. Every footfall was a surprise, a drop or a jolt. No shadows. An even, white, soundless sphere: we moved along inside a huge frosted-glass ball. There was nothing inside the ball, and nothing was outside it. But there were cracks in the glass. Probe and step, probe and step. Probe for the invisible cracks through which one might fall out of the white glass ball, and fall, and fall, and fall… An unrelaxable tension little by little took hold of all my muscles. It became exceedingly difficult to take even one more step.

"What's up, Genry?"

I stood there in the middle of nothing. Tears came out and froze my eyelids together. I said, "I'm afraid of falling."

"But you're on the rope," he said. Then, coming up and seeing that there was no crevasse anywhere visible, he saw what was up and said, "Pitch camp."

"It's not time yet, we ought to go on."

He was already unlashing the tent.

Later on, after we had eaten, he said, "It was time to stop. I don't think we can go this way. The Ice seems to drop off slowly, and will be rotten and crevassed all the way. If we could see, we could make it: but not in unshadow."

"But then how do we get down onto the Shenshey Bogs?"

"Well, if we keep east again instead of trending south, we might be on sound ice clear to Guthen Bay. I saw the Ice once from a boat on the Bay in summer. It comes up against the Red Hills, and feeds down in ice-rivers to the Bay. If we came down one of those glaciers we could run due south on the sea-ice to Karhide, and so enter at the coast rather than the border, which might be better. It will add some miles to our way, though— something between twenty and fifty, I should think. What's your opinion, Genry?"

"My opinion is that I can't go twenty more feet so long as the white weather lasts."

"But if we get out of the crevassed area…"

"Oh, if we get out of the crevasses I'll be fine. And if the sun ever comes out again, you get on the sledge and I'll give you a free ride to Karhide." That was typical of our attempts at humor, at this stage of the journey; they were always very stupid, but sometimes theyВ madeВ the other fellow smile. "There's nothing wrong with me," I went on, "except acute chronic fear."

"Fear's very useful. Like darkness; like shadows." Estraven's smile was an ugly split in a peeling, cracked brown mask, thatched with black fur and set with two flecks of black rock. "It's queerВ thatВ В daylight's not enough. We need the shadows, in order to walk."

"Give me your notebook a moment."

He had just noted down our day's journey and done some calculation of mileage and rations. He pushed the little tablet and carbon-pencil around the Chabe stove to me. On the blank leaf glued to the inner back cover I drew the double curve within the circle, and blacked the yin half of the symbol, then pushed it back to my companion. "Do you know that sign?"

He looked at it a long time with a strange look, but he said, "No."

"It's found on Earth, and on Hain-Davenant, and on Chiffewar. It is yin and yang. Light is the left hand of darkness… how did it go? Light, dark. Fear, courage. Cold, warmth. Female, male. It is yourself, Therem. Both and one. A shadow on snow."

The next day we trudged northeast through the white absence of everything until there were no longer any cracks in the floor of nothing: a day's haul. We were on 2⁄3 ration, hoping to keep the longer route from running us right out of food. It seemed to me that it would not matter much if it did, as the difference between little and nothing seemed a rather fine one. Estraven, however, was on the track of his luck, following what appeared to be hunch or intuition, but may have been applied experience and reasoning. We went east for four days, four of the longest hauls we had made, eighteen to twenty miles a day, and then the quiet zero weather broke and went to pieces, turning into a whirl, whirl, whirl of tiny snow-particles ahead, behind, to the side, in the eyes, a storm beginning as the light died. We lay in the tent for three days while the blizzard yelled at us, a three-day-long, wordless, hateful yell from the unbreathing lungs.

"It'll drive me to screaming back, " I said to Estraven in mindspeech, and he, with the hesitant formality that marked his rapport: "No use. It will not listen. "

We slept hour after hour, ate a little, tended our frostbites, inflammations, and bruises, mindspoke, slept again. The three-day shriek died down into a gabbling, then a sobbing, then a silence. Day broke. Through the opened door-valve the sky's brightness shone. It lightened the heart, though we were too rundown to be able to show our relief in alacrity or zest of movement. We broke camp—it took nearly two hours, for we crept about like two old men—and set off. The way was downhill, an unmistakable slight grade; the crust was perfect for skis. The sun shone. The thermometer at midmorning showed −10°. We seemed to get strength from going, and we went fast and easy. We went that day till the stars came out.

For dinner Estraven served out full rations. At that rate, we had enough for only seven days more.

"The wheel turns," he said with serenity. "To make a good run, we've got to eat."

"Eat, drink, and be merry," said I. The food had got me high. I laughed inordinately at my own words. "All one-eating-drinking-merrymaking. Can't have merry without eats, can you?" This seemed to me a mystery quite on a par with that of the yin-yang circle, but it did not last. Something in Estraven's expression dispelled it. Then I felt like crying, but refrained. Estraven was not as strong as I was, and it would not be fair, it might make him cry too. He was already asleep: he had fallen asleep sitting up, his bowl on his lap. It was not like him to be so unmethodical. But it was not a bad idea, sleep.

We woke rather late next morning, had a double breakfast, and then got in harness and pulled our light sledge right off the edge of the world.

Below the world's edge, which was a steep rubbly slope of white and red in a pallid noon light, lay the frozen sea: the Bay of Guthen, frozen from shore to shore and from Karhide clear to the North Pole.