We covered the next mile in less than half an hour. The going was easier now, much easier than it had been, although we still had to make small detours around rafted, compacted and broken ice: on the debit side, all of us, Zabrinski excepted, were near complete exhaustion, stumbling and falling far more often than was warranted by the terrain and the strength of the ice gale. For myself, my leaden, 'dragging legs felt as if they were on fire; each step now sent a shooting pain stabbing from my ankle clear to the top of my thigh. For all that, I think I could have kept going longer than any of them, even Zabrinski, for I had the motivation, the driving force that would have kept me going hours after my legs would have told me that it was impossible to carry on a step further. Major John Halliwell. My elder, my only brother. Alive or dead. Was he alive or was he dead, this one man in the world to whom I owed everything I had or had become? Was he dying, at that very moment when I was thinking of him, was he dying? His wife, Mary, and his three children, who spoiled and mined their bachelor uncle as I spoiled and ruined them: whatever way it was, they would have to know, and only I could tell them. Alive or dead? My legs weren't mine; the stabbing fire that tortured them belonged to some other man, not to me. I had to know, I had to know, and if I had to find out by covering whatever miles lay between me and Drift Ice Station Zebra on my hands and knees, then I would do just that. I would find out. And over and above the tearing anxiety as to what had happened to my brother there was yet another powerful motivation, a motivation that the world would regard as of infinitely greater importance than the life or death of the commandant of the station. As infinitely more important than the living or dying of the score of men who manned that desolate polar outpost. Or so the world would say.

The demented drumming of the spicules on my mask and ice-sheathed furs suddenly eased, the gale wind fell away, and I found myself standing in the shelter of an ice ridge even higher than the last one we'd used for shelter. I waited for the others to come up, asked Zabrinski to make a position check with the «Dolphin», and doled out some more of the medicinal alcohol. More of it than on the last occasion. We were in more need of it. Both Hansen and Rawlings were in a very distressed condition, their breath whistling in and out of their lungs in the rapid, rasping, shallow panting of a long-distance runner in the last tortured moments of his final exhaustion. I became gradually aware that the speed of my own breathing matched theirs almost exactly; it required a concentrated effort of willpower to bold my breath even for the few seconds necessary to gulp down my drink. I wondered vaguely if perhaps Hansen hadn't been right after all; maybe the alcohol wasn't good for us. But it certainly tasted as if it were.

Zabrinski was already talking through cupped hands into the microphone. After a minute or so he pulled the earphone out from under his parka and buttoned up the walkie-talkie set. He said: "We're either good or lucky or both. The «Dolphin» says we're exactly on the course we ought to be on." He drained the glass I handed him and sighed in satisfaction. "Well, that's the good part of the news. Here comes the bad part. The sides of the polynya the «Dolphin» is lying in are beginning to close together. They're closing pretty fast. The captain estimates he'll have to get out of it in two hours. Two at the most." He paused, then finished slowly: "And the ice machine is still on the blink."

"The ice machine," I said stupidly. Well, anyway, I felt stupid, I don't know how I sounded. "Is the ice — "

"It sure is, brother," Zabrinski said. He sounded tired. "But you didn't believe the skipper, did you, Dr. Carpenter? You were too clever for that."

"Well, that's a help," Hansen said heavily. "That makes everything just dandy. The «Dolphin» drops down, the ice closes up, and there we are, the «Dolphin» below, us on top, and the whole of the polar ice cap between us. They'll almost certainly never manage to find us again, even if they do fix the ice machine. Shall we just lie down and die now or shall we first stagger around in circles for a couple of hours and then lie down and die?"

"It's tragic," Rawlings said gloomily. "Not the personal aspect of it, I mean the loss to the U.S. Navy. I think I may fairly say, Lieutenant, that we are — or were — three promising young men. Well, you and me, anyway. I think Zabrinski there had reached the limit of his potentialities. He reached them a long time ago."

Rawlings got all this out between chattering teeth and still painful gasps of air. Rawlings, I reflected, was very much the sort of person I would like to have by my side when things began to get awkward, and it looked as if things were going to become very awkward indeed. He and Zabrinski had, as I'd found out, established themselves as the homespun if slightly heavy-handed humorists on the «Dolphin». For reasons known only to themselves, both men habitually concealed intelligences of a high order and advanced education under a cloak of genial buffoonery.

"Two hours yet," I said. "With this wind at our backs we can be back in the sub in well under an hour. We'd be practically blown back there."

"And the men on Drift Station Zebra?" Zabrinski asked.

"We'd have done our best. Just one of those things."

"We are profoundly shocked, Dr. Carpenter," Rawlings said. The tone. of genial buffoonery was less noticeable than usual.

"Deeply dismayed," Zabrinsld added, "by the very idea." The words were light, but the lack of warmth in the voice had nothing to do with the bitter wind.

"The only dismaying thing around here is the level of intelligence of certain simple-minded sailors," Hansen said with some asperity. He went on, and I wondered at the conviction in his voice: "Sure, Dr. Carpenter thinks we should go back. That doesn't include him. Dr. Carpenter wouldn't turn back now for all the gold in Fort Knox." He pushed himself wearily to his feet. "Can't be much more than half a mile to go now. Let's get it over with."

In the backwash of light from my flashlight I saw Rawlings and Zabrinski glance at each other, saw them shrug their shoulders at the same moment. Then they, too, were on their feet and we were on our way again.

Three minutes later Zabrinski broke his ankle.

It happened in an absurdly simple fashion, but for all its simplicity it was a wonder that nothing of the same sort had happened to any of us in the previous three hours. After starting off again, instead of losing our bearing by working to the south or north until we had rounded the end of the ice ridge blocking our path, we elected to go Over it. The ridge was all of ten feet high but by boosting and pulling each other we reached the top without much difficulty. I felt my way forward cautiously, using the ice probe; the flashlight was useless in that ice storm, and my goggles completely opaque. After twenty feet of crawling across the gently downward-sloping surface, I reached the fax side of the ridge and stretched down with the probe.

"Five feet," I called to the others as they came up. "It's only five feet." I swung over the edge, dropped down, and waited for the others to follow. Hansen came first, then Rawlings, both sliding down easily beside me. What happened to Zabrinski was impossible to see: he either misjudged his distance from the edge or a sudden easing of the wind made him lose his footing. Whatever the cause, I heard him call out, the words whipped away and lost by the wind, as he jumped down beside us. He seemed to land squarely and lightly enough on his feet, then cried out sharply and fell heavily to the ground.

I turned my back to the ice storm, raised the useless snow goggles, and pulled out my flashlight. Zabrinski was half sitting, half lying on the ice, propped up on his right elbow and cursing steadily and fluently and, as far as I could tell, because of the muffling effect of his snow mask, without once repeating himself. His right heel was jammed in a fourinch crack in the ice, one of the thousands of such fractures and fissures that criss-crossed the pressure areas of the pack; his right leg was bent over at an angle to the outside, an angle normally impossible for any leg to assume. I didn't need to have a medical diploma hung around my neck to tell that the ankle was gone: either that or the lowermost part of the tibia, for the ankle was so heavily encased in a stout boot with lace binding that most of the strain must have fallen on the shinbone. I hoped it wasn't a compound fracture, but it was an unreasonable hope: at that acute angle the snapped bone could hardly have failed to pierce the skin. Compound or not, it made no immediate difference; I'd no intention of examining it. A few minutes' exposure of the lower part of his leg in those temperatures was as good a way as any of ensuring that Zabrinski went through the rest of his life with one foot missing.