Ice Station Zebra

3

"There it is, then," said Swanson. "That's the Barrier."

The «Dolphin», heading due north, her great cylindrical bulk at one moment completely submerged, the next showing clear as she rolled heavily through the steep quartering seas, was making less than three knots through the water, the great nuclear-powered engines providing just enough thrust to the big twin eight-foot propellers to provide steerage way and no more. Thirty feet below where we stood on the bridge the finest sonar equipment in the world was ceaselessly probing the waters all around us but even so Swanson was taking no chances on the effects of collision with a drifting ice block. The noon-day Arctic sky was so overcast that the light was no better than that of late dusk. The bridge thermometer showed the sea temperature to be 28°F., the air temperature — I 6°F. The gale-force wind from the northeast was snatching the tops off the rolling steel-gray waves and subjecting the steep-walled sides of the great conning tower — "sail," the crew called it — to the ceaseless battering of a bullet-driven spray that turned to solid ice even as it struck. The cold was intense.

Shivering uncontrollably, wrapped in a heavy duffel coat and oilskins and huddled against the illusory shelter of the canvas wind-dodger, I followed the line of Swanson's pointing ann; even above the high, thin, shrill whine of the wind and the drum-fire of the flying spray against the sail, I could hear the violent chattering of his teeth. Less than two miles away a long, thin, grayish-white line, at that distance apparently smooth and regular, seemed to stretch the entire width of the northern horizon. Fd seen it before and it wasn't much to look at but it was a sight a man never got used to, not because of itself but because of what it represented: the beginning of the polar ice cap that covered the top of the world, at this time of year a solid, compacted mass of ice that stretched clear from where we lay right across to Alaska on the other side of the world. And we had to go under that mass. We had to go under it to find men hundreds of miles away, men who might be already dying, men who might be already dead. Who probably were dead. Men, dying or dead, whom we had to seek out by guess and by God in that great wasteland of ice stretching out endlessly before us, for we did not know where they were.

The relayed radio message we had received just fortynine hours ago had been the last. Since then, there had been only silence. The trawler «Morning Star» had been sending almost continuously in the intervening two days, trying to raise Drift Station Zebra, but out of that bleak desert of ice to the north had come nothing but silence. No word, no signal, no faintest whisper of sound had come out of that desolation.

Eighteen hours before, the Russian atomic-engined «Dvina» had reached the Barrier and had started on an all-out and desperate attempt to smash its way into the heart of the ice cap. In this early stage of winter the ice was neither so thick nor so compacted as it would be at the time of its maximum density, in March, and the very heavily armored and powerfully engined «Dvina» was reputed to be able to break through ice up to a thickness of eighteen feet: given fair conditions, the «Dvina» was widely believed to be capable of battering its way to the North Pole. But the conditions of the rafted ice had proved abnormal to a degree and the attempt a hopeless one. The «Dvina» had managed to crash its way over forty miles into the ice cap before being permanently stopped by a thick wall of rafter ice over twenty feet in height and probably more than a hundred deep. The «Dvina», according to reports, had sustained heavy damage to its bows and was still in the process of extricating itself, with the greatest difficulty, from the pack. A very gallant effort that had achieved nothing except an improvement in East-West relations to an extent undreamed of for many years.

Nor had the Russians' efforts stopped there. Both they and the Americans had made several flights over the area with front-line long-range bombers. Through the deep overcast and driving ice and snow-filled winds, those planes had criss-crossed the suspected area a hundred times searching with their fantastically accurate radar. But not one single radar sighting had been reported. Various reasons had been put forward to explain the failure, especially the failure of the Strategic Air Command's B52 bomber whose radar was known to be easily capable of picking out a hut against contrasting background from ten thousand feet and in pitch darkness. It had been suggested that the huts were no longer there: that the radar's eye was unable to distinguish between an ice-sheathed hut and the thousands of ice hummocks that dot the polar cap in winter: and that they had been searching in the wrong area in the first place. The most probable explanation was that the radar waves had been blurred and deflected by the dense clouds of ice spicules blowing over the area. Whatever the reason, Drift Ice Station Zebra remained as silent as if no life bad ever been there, as lost as if it had never existed.

"There's no percentage in staying up here and getting frozen to death." Commander Swanson's voice was a half-shout, it had to be to make him heard. "If we're going under that ice, we might as well go now." He turned his back to the wind and stared out to the west where a big, broad-beamed trawler was rolling heavily and sluggishly in the seas less than a quarter of a mile away. The «Morning Star», which had closed right up to the edge of the ice pack over the last two days, listening, waiting, and all in vain, was about to return to Hull: her fuel reserves were running low.

"Send them this message," Swanson said to the seaman by his side. "'We are about to dive and proceed under the ice. We do not expect to emerge for minimum four days, are prepared to remain maximum fourteen.'" He turned to me and said, "If we can't find them in that time — " and left the sentence unfinished.

I nodded, and he went on with the message: "'Many thanks for your splendid co-operation. Good luck and a safe trip home.'" As the signalman's lamp started chattering out its message, he said wonderingly, "Do those fishermen trawl up in the Arctic the entire winter?"

"They do."

"The whole winter. Fifteen minutes and I'm about dead. Just a bunch of decadent limeys, that's what they are." A lamp aboard the «Morning Star» flickered for some seconds, and Swanson said, "What reply?"

"Mind your heads under that ice. Good luck and goodby."

"Everybody below," Swanson said. As the signalman began to strip the canvas dodger, I dropped down a ladder into a small compartment beneath, wriggled through a hatch and down a second ladder to the pressure hull of the submarine, another hatch, a third ladder, and then I was on the control deck of the «Dolphin». Swanson and the signalman followed, then last of all Hansen, who had to close the two heavy water-tight doors above.

Commander Swanson's diving technique would have proved a vast disappointment to those brought up on a diet of movie submarines. No frenzied activity, no tense, steely-eyed men hovering over controls, no dramatic calls of "Dive, dive, dive," no blaring of kiaxons. Swanson reached down a steel-spring microphone, said quietly, "This is the captain. We are about to move under the ice. Diving now," hung up and said: "Three hundred feet."

The chief electronics technician leisurely checked the rows of lights indicating all hatches, surface openings, and valves closed to the sea. The disc lights were out: the slot lights burned brightly. Just as leisurely he rechecked them, glanced at Swanson and said, "Straight line shut, sir." Swanson nodded. Air hissed loudly out of the ballast tanks, and that was it. We were on our way. It was about as wildly exciting as watching a man push a wheelbarrow. And there was something oddly reassuring about it all.

Ten minutes later Swanson came up to me. In the past two days I'd come to know Commander Swanson fairly well, like him a lot, and respect him tremendously. The crew had complete and implicit faith in him. I was beginning to have the same thing. He was a kindly, genial man with a vast knowledge of every aspect of submarining, a remarkable eye for detail, an even more remarkably acute mind and an imperturbability that remained absolute tinder all conditions. Hansen, his executive officer and clearly no respecter of persons, had said flatly that Swanson was the best submarine officer in the Navy. I hoped he was right; that was the kind of man I wanted around in conditions like these.

"We're about to move under the ice now, Dr. Carpenter," he said. "How do you feel about it?"

"I'd feel better if I could see where we were going."

"We can see," he said. "We've got the best eyes in the world aboard the «Dolphin». We've got eyes that look down, around, ahead, and straight up. Our downward eye is the fathometer, or echo-sounder, which tells us just how deep the water below our keel is and as we have about five thousand feet of water below our keel at this particular spot, we're hardly likely to bump into underwater projections and its use right now is purely a formality. But no responsible navigation officer would ever think of switching it off. We have two sonar eyes for looking around and ahead, one sweeping the ship, another searching out a fifteen-degree path on either side of the bow. Sees everything, hears everything. You drop a wrench on a warship twenty miles away and we know all about it. Fact. Again it seems purely a formality. The sonar is searching for underwater ice stalactites forced down by the pressure of rafted ice above, but in five trips under the ice and two to the Pole, I've never seen underwater stalactites or ridges deeper than two hundred feet, and we're at three hundred feet now. But we still keep them on."

"You might bump into a whale?" I suggested.

"We might bump into another submarine." He wasn't smiling. "And that would be the end of both of us. What with the Russian and our own nuclear submarines busy crisscrossing to and fro across the top of the world, the underside of the polar ice cap is getting more like Times Square every day."

"But surely the chances — "

"What are the chances of mid-air collision to the only two iiruaft occupying ten thousand square miles of sky? On paper, they don't exist. There have been three such collisions this year already. So we keep the sonar pinging. But the really important eye, when you're under the ice, is the one that looks up. Come and have a look at it."

He led the way to the after-starboard end of the control room, where Dr. Benson and another man were busy studying a glassed-in eye-level machine that outwardly consisted of a seven-inch-wide moving ribbon of paper and an inked stylus that was tracing a narrow, straight black line along it. Benson was engrossed in adjusting some of the calibrated controls.

"The surface fathometer," Swanson said. "Better known as the ice machine. It's not really Dr. Benson's machine at all, we have two trained operators aboard, but as we see no way of separating him from it without actually courtmartialing him, we take the easy way out and let him be." Benson grinned, but his eye didn't leave the line traced out by the stylus. "Same principle as the echo-sounding machine: it just bounces an echo back from the ice — when there is any. That thin black line you see means open water above. When we move under the ice, the stylus has an added vertical motion which not only indicates the presence of ice but also gives us its thickness."

"Ingenious," I said.

"It's more than that. Under the ice it can be life or death for the «Dolphin». It certainly means life or death for Drift Station Zebra. If we ever get its position, we can't reach it until we break through the ice, and this is the only machine that can tell us where the ice is thinnest."

"No open water at this time of year? No leads?"

"'Polynyas,' we call them. None. Mind you, the ice pack is never static, not even in winter, and surface-pressure changes can very occasionally tear the ice apart and expose open water. With air temperatures such as you get in winter, you can guess how long the open water stays in a liquid condition. There's a skin of ice on it in five minutes, as inch in an hour, and a foot inside two days. If we ge to one of those frozen-over polynyas inside, say, three days we've got a fair chance of breaking through."

"With the conning tower?"

"That's it. The sail. All new nuclear subs have specially strengthened sails designed for one purpose only: breaking through Arctic ice. Even so we have to go pretty gently as the shock, of course, is transmitted to the pressure hull."

I thought about this for a moment and then said, "What happens to the pressure hull if you come up too fast — as I understand may happen with a sudden change in salinity and sea temperature — and you find out at the last minute that you've drifted away from the indicated area of thin ice and have ten solid feet of the stuff above you?"

"That's it," he said. "Like you say, it's the last minute. Don't even think about such things, much less talk about them: I can't afford to have nightmares on this job." I looked at him closely, but he wasn't smiling any more. He lowered his voice. "I don't honestly think that there is one member of the crew of the «Dolphin» who doesn't get a little bit scared when we move in under the ice. I know I do. I think this is the finest ship in the world, Dr. Carpenter, but there are still a hundred things that can go wrong with it, and if anything happens to the reactor or the steam turbines or the electrical generators, then we're already in our coffin and the lid screwed down. The ice pack above is the coffin lid. In the open sea, most of those things don't matter a damn: we just surface or go to snorkel depth and proceed on our diesels. But for diesels you need air — and there's no air under the ice pack. So if anything hap. pens we either find a polynya to surface in, one chance in ten thousand at this time of year, before our standby battery gives Out, or… well, that's it."

"This is all very encouraging," I said.

"Isn't it?" He smiled, none too soon for me. "It'll never happen. What's the worthy Benson making all the racket about?"

"Here it is," Benson called. "The first drift block. And another. And another! Come and have a look, Doctor."

I had a look. The stylus, making a faint, soft hissing sound, was no longer tracing out a continuously horizontal line, but was moving rapidly up and down across the paper, tracing out the outline of the block of ice passing astern above us. Another thin, straight line, more agitated vertical movements of the stylus, and again another block of ice had gone. Even as I watched, the number of thin, horizontal lines became fewer and fewer and shorter and shorter until eventually they disappeared altogether.

"That's it, then," Swanson nodded. "We'll take her deep now, real deep, and open up all the stops."

When Commander Swanson had said he was going to hurry, he'd meant every word of it. In the early hours of the following morning I was awakened from a deep sleep by a heavy hand on my shoulder. I opened my eyes, blinked against the glare of the overhead light, then saw Lieutenant Hansen.

"Sorry about the beauty sleep, Doc," he said cheerfully. "But this is it."

"This is what?" I said irritably.

"85° 35' north, 21 °20' east — the last estimated position of Drift Station Zebra. At least, the last estimated position with estimated correction for polar drift."

"Already?" I glanced at my watch, not believing it. "We're there already?"

"We have not," Hansen said modestly, "been idling. The skipper suggests you come along and watch us at work."

"I'll be right with you." When and if the «Dolphin» managed to break through the ice and began to try her one-in-amillion chance of contacting Drift Station Zebra, I wanted to be there.

We left Hansen's cabin and had almost reached the control room when I lurched, staggered, and would have fallen but for a quick grab at a hand rail that ran along one side of the passageway. I hung on grimly as the «Dolphin» banked violently sideways and around like a fighter plane in a tight turn. In my experience, no submarine had ever been able to begin to behave even remotely in that fashion. I understood now the reasons for the safety belts on the diving-control seats.

"What the hell's up?" I said to Hansen. "Avoiding some underwater obstruction ahead?"

"Must be a possible polynya. Some place where the ice is thin, anyway. As soon as we spot a possible like that, we come around like a dog chasing its own tail, just so we don't miss it. It makes us very popular with the crew, especially when they're drinking coffee or soup."

We went into the control room. Commander Swanson, flanked by the navigator and another man, was bent over the plotting table, examining something intently. Farther aft, a man at the surface fathometer was reading out ice-thickness figures in a quiet, unemotional voice. Commander Swanson looked up from the chart.

"Morning, Doctor. John, I think we may have something here."

Hansen crossed to the plot and peered at it. There didn't seem to be much to peer at — a tiny pinpoint of light shining through the glass top of the plot and a squared sheet of chart paper marked by a most unseamanlike series of wavering black lines traced out by a man with a pencil following the track of the tiny moving light. There were three red crosses superimposed on the paper, two very close together, and just as Hansen was examining the paper the crewman manning the ice machine — Dr. Benson's enthusiasm for his toy did not, it appeared, extend to the middle of the night — called out "'Marl!" Immediately the black pencil was exchanged for a red and a fourth cross made.

"'Think' and 'may' are just about right, Captain," Hansen said. "It looks awfully narrow to me."

"It looks the same way to me, too," Swanson, admitted. "But it's the first break in the heavy ice that we've had in an hour, almost. And the further north we go, the poorer our chances. Let's give it a try. Speed?"

"One knot," Raeburn said.

"All back one third," Swanson said. No sharp imperatives, not ever, in the way Swanson gave his orders, more a quiet and conversational suggestion, but there was no mistaking the speed with which one of the crewmen strapped into the diving-stand bucket seat leaned forward to telegraph the order to the engine room. "Left full rudder."

Swanson bent over to check the plot, closely watching the tiny pinpoint of light and the tracing pencil move back toward the approximate center of the elongated triangle formed by the four red crosses. "All stop," he went on. "Rudder amidships." A pause, then: "All ahead one third. No. All stop."

"Speed zero," Raeburn said.

"Twenty-one twenty feet," Swanson said to the diving officer. "But gently, gently."

A strong, steady hum echoed in the control center. I asked Hansen, "Blowing ballast?"

He shook his head. "Just pumping the stuff out. Gives a far more precise control of rising speed and makes it easier to keep the sub on an even keel. Bringing a stopped sub up on a dead even keel is no trick for beginners. Conventional subs never try this sort of thing."

The pumps stopped. There came the sound of water flooding back into the tanks as the diving officer slowed up at the rate of ascent. The sound faded.

"Secure flooding," the diving officer said. "Steady on one hundred feet."

"Up periscope," Swanson said to the crewman by his side. An overhead lever was engaged, and we could hear the hiss of high-pressure oil as the hydraulic piston began to lift the starboard periscope off its seating. The gleaming cylinder rose slowly against the pressure of the water outside until finally the foot of the periscope cleared its well. Swanson opened the hinged hand grips and peered through the eye-piece.

"What does he expect to see in the middle of the night at this depth?" I asked Hansen.

"Never can tell. It's rarely completely dark, as you know. Maybe a moon, maybe only stars, but even starlight will show as a faint glow through the ice-if the ice is thin enough."

"What's the thickness of the ice above, in this rectangle?"

"The sixty-four-dollar question," Hansen admitted, "and the answer is that we don't know. To keep that ice machine to a reasonable size, the graph scale has to be very small. Anything between four and forty inches. Four inches we go through like the icing on a wedding cake: forty inches and we get a very sore head indeed." He nodded across to Swanson. "Doesn't look so good. That grip he's twisting is to tilt the periscope lens upward and that button is for focusing. Means he's having trouble in finding anything."

Swanson straightened. "Black as the earl of hell's waistcoat," he said conversationally. "Switch on hull and sail floodlights."

He stooped and looked again. For a few seconds only. "Pea soup. Thick and yellow and strong. Can't see a thing. Let's have the camera, shall we?"

I looked at Hansen, who nodded to a white screen that had just been unshuttered on the opposite bulkhead. "All mod cons, Doc, Closed-circuit TV. Camera is deck mounted under toughened glass and can be remote-controlled to look up or around."

"You could do with a new camera, couldn't you?" The TV screen was gray, fuzzy, featureless.

"Best that money can buy," Hansen said. "It's the water. Under certain conditions of temperature and salinity, it becomes almost completely opaque when flood-lit. Like driving into a heavy fog with your headlights full on."

"Floodlights off," Swanson said. The screen became quite blank. "Floodlights on." The same drifting, misty gray as before. Swanson sighed and turned to Hansen. "Well, John?"

"If I were paid for imagining things," Hansen said carefully, "I could imagine I see the top of the sail in that left corner. Pretty murky out there, Captain. Blindman's buff, is that it?"

"Russian roulette, I prefer to call it." Swanson had the clear, unworried face of a man contemplating a Sunday afternoon in a deck chair. "Are we holding position?"

"I don't know." Raeburn looked up from the plot. "It's difficult to be sure."

"Sanders?" This to the man at the ice machine.

"Thin ice, sir. Still thin ice."

"Keep calling. Down periscope." He folded the handles up and turned to the diving officer. "Take her up like we were carrying a crate of eggs atop the sail and didn't want to crack even one of them."

The pumps started again. I looked around the control room. Swanson excepted, everyone was quiet and still and keyed-up. Raeburn's face was beaded with sweat, and Sanders' voice was too calm and impersonal by half as he kept repeating, "Thin ice, thin ice" in a low monotone. You could reach out and touch the tension in the air. I said quietly to Hansen, "Nobody seems very happy. There's still a hundred feet to go."

"There's forty feet," Hansen said shortly. "Readings are taken from keel level, and there's sixty feet between the keel and the top of the sail. Forty feet minus the thickness of the ice-and maybe a razor-sharp or needle-pointed stalactite sticking down ready to skewer the «Dolphin» through the middle. You know what that means?"

"That it's time I started getting worried too?"

Hansen smiled, but he wasn't feeling like smiling. Neither Was I, not any more.

"Ninety feet," the diving officer said.

"Thin ice, thin ice," Sanders intoned.

"Switch off the deck flood, leave the sail flood on," Swanson said. "And keep that camera moving. Sonar?"

"All clear," the sonar operator reported. "All clear all around." A pause then: "No, hold it, hold it! Contact dead astern!"

"How close?" Swanson asked quickly.

"Too close to say. Very close."

"She's jumping!" the diving officer called out sharply. "Eighty, seventy-five." The «Dolphin» had hit a layer of colder water or extra salinity.

"Heavy ice, heavy ice!" Sanders called out urgently.

"Flood emergency!" Swanson ordered — and this time it was an order.

I felt the sudden build-up of air pressure as the diving officer vented the negative tank and tons of seawater poured into the emergency diving tank. But it was too late. With a shuddering, jarring smash that sent us staggenng, the «Dolphin» crashed violently into the ice above, glass tinkled, lights went out and the submarine started falling like a stone.

"Blow negative to the mark!" the diving officer called. High-pressure air came boiling into the negative tank; at our rate of falling, we would have been flattened by the sea pressure before the pumps could even have begun to cope with the huge extra ballast load we had taken aboard in seconds. Two hundred feet, two hundred and fifty, and we were still falling. Nobody spoke; everybody just stood or sat in a frozen position staring at the diving stand. It required no gift for telepathy to know the thought in every mind. It was obvious that the «Dolphin» had been struck aft by some underwater pressure ridge at the same instant as the sail had hit the heavy ice above. If the «Dolphin» had been holed aft, this descent wasn't going to stop until the pressure of a million tons of water crushed and flattened the hull and in a ificker of time snuffed out the life of every man inside it.

"Three hundred feet," the diving officer called out. "Three fifty — and she's slowing. She's slowing."

The «Dolphin» was still falling, sluggishly passing the four hundred-foot mark, when Rawlings appeared in the control room, tool kit in one hand, a crate of assorted lamps in the other.

"It's unnatural," he said. He appeared to be addressing the shattered lamp above the plot which he had immediately begun to repair. "Contrary to the laws of nature, I've always maintained. Mankind was never meant to probe beneath the depths of the ocean. Mark my words, these newfangled inventions will come to a bad end."

"So will you if don't keep quiet," Commander Swanson said acidly. But there was no reprimand in his face; he appreciated as well as any of us the therapeutic breath of fresh air that Rawlings had brought into that tension-laden atmosphere. "Holding?" he said to the diving officer.

The diving officer raised a finger and grinned. Swanson nodded and swung the coiled-spring microphone in front of him. "Captain speaking," he said calmly. "Sorry about that bump. Report damage at once."

A green light flashed in the panel of a box beside him. Swanson touched a switch and a loud-speaker in the deckhead crackled.

"Maneuvering room." The maneuvering room was in the after end of the upper-level engine room, toward the stern. "Hit was directly above us here. We could do with a box of candles, and some of the dials and gauges are out of kilter. But we still got a roof over our heads."

"Thank you, Lieutenant. You can cope?"

"Sure we can."

Swanson pressed another switch. "Stern room?"

"We still attached to the ship?" a cautious voice inquired.

"You're still attached to the ship," Swanson assured him. "Anything to report?"

"Only that there's going to be an awful lot of dirty laundry by the time we get back to Scotland. The washing machine's had a kind of fit."

Swanson smiled and switched off. His face was untroubled; he must have had a special sweat-absorbing mechanism on his face. I felt I could have done with a bath towel. He said to Hansen, "That was bad luck. A combination of a current where a current had no right to be, a temperature inversion where a temperature inversion had no right to be, and a pressure ridge where we least expected it. Not to mention the damned opacity of the water. What's required is a few circuits until we know this polynya like the backs of our hands, a small off-set to allow for drift and a little precautionary flooding as we approach the ninety-foot mark."

"Yes, sir. That's what's required. Point is, what are we going to do?"

"Just that. Take her up and try again."

I had my pride so I refrained from mopping my brow. They took her up and tried again. At two hundred feet and for fifteen minutes Swanson juggled propellers and rudder until he had the outline of the frozen polynya above as accurately limned on the plot as he could ever expect to have it. Then he positioned the «Dolphin» just outside one of the boundary lines and gave an order for a slow ascent.

"One hundred twenty feet," the diving officer said. "One hundred ten."

"Heavy ice," Saunders intoned. "Still heavy ice."

Sluggishly the «Dolphin» continued to rise. Next time in the control room, I promised myself, I wouldn't forget that bath towel. Swanson said, "If we've overestimated the speed of the drift, there's going to be another bump, I'm afraid." He turned to Rawlings, who was still repairing lights. "If I were you, I'd suspend operations for the present. You may have to start all over again in a moment, and we don't carry all that number of spares aboard."

"One hundred feet," the diving officer said. He didn't sound as unhappy as his face looked.

"The water's clearing," Hansen said suddenly. "Look."

The water had cleared, not dramatically so, but enough. We could see the top corner of the sail clearly outlined on the TV screen. And then, suddenly, we could see something else again, heavy, ugly ridged ice not a dozen feet above the sail.

Water flooded into the tanks. The diving officer didn't have be to told what to do: we'd gone up like an express elevator the first time we'd hit a different water layer, and once like that was enough in the life of any submarine.

"Ninety feet," he reported. "Still rising." More water flooded in, and then the sound died away. "She's holding. Just under ninety feet."

"Keep her there." Swanson stared at the TV screen. "We're drifting clear and into the polynya — I hope."

"Me too," Hansen said. "There can't be more than a couple of feet between the top of the sail and that damned ugly stuff."

"There isn't much room," Swanson acknowledged. "Sanders?"

"Just a moment, sir. The graph looks kinda funny — No, we're clear." He couldn't keep the excitement out of his voice. "Thin ice!"

I looked at the screen. He was right. I could see the vertical edge of a wall of ice move slowly across the screen, exposing clear water above.

"Gently, now, gently," Swanson said. "And keep that camera on the ice wall at the side, then straight up, turn about."

The pumps began to throb again. The ice wall, less than ten yards away, began to drift slowly down past us.

"Eighty-five feet," the diving officer reported. "Eighty."

"No hurry," Swanson said. "We're sheltered from that drift by now."

"Seventy-five feet." The pumps stopped, and water began to flood into the tanks. "Seventy." The «Dolphin» was almost stopped now, drifting upward as gently as thistledown. The camera switched upward, and we could see the top corner of the sail clearly outlined with a smooth ceiling of ice floating down to meet it. More water gurgled into the tanks, the top of the sail met the ice with a barely perceptible bump, and the «Dolphin» came to rest.

"Beautifully done," Swanson said warmly to the diving officer. "Let's try giving that ice a nudge. Are we slewing?"

"Bearing constant."

Swanson nodded. The pumps hummed, poured out water, lightening ship, steadily increasing positive buoyancy, The ice stayed where it was. More time passed, more water pumped out, and still nothing happened. I said softly to Hansen, "Why doesn't he blow the main ballast? You'd get a few hundred tons of positive buoyancy in next to no time, and even if that ice is forty inches thick, it couldn't survive all that pressure at a concentrated point." -

"Neither could the «Dolphin»," Hansen said grimly. "With a suddenly induced big positive buoyancy like that, once she broke through, she'd go up like a cork from a champagne bottle. The pressure hull might take it, I don't know, but sure as little apples the rudder would be squashed as flat as a piece of tin. Do you want to spend what little's left of your life traveling in steadily decreasing circles under the polar ice cap?"

I didn't want to spend what little was left of my life in traveling in steadily decreasing circles under the ice cap, so I kept quiet. I watched Swanson as he walked across to the diving stand and studied the banked dials in silence for some seconds. I was beginning to become a little apprehensive about what Swanson would do next. I was beginning to realize, and not slowly, either, that he was a man who didn't give up very easily.

"That's enough of that," he said to the diving officer. "If we go through now with all this pressure behind us, we'll be airborne. This ice is even thicker than we thought. We've tried the long, steady shove and it hasn't worked. A sharp tap is obviously what is needed. Flood her down, but gently, to eighty feet or so. A good sharp whiff of air into the ballast tanks, and we'll give our well-known imitation of a bull at a gate."

Whoever had installed the 240-ton air-conditioning unit in the «Dolphin» should have been prosecuted; it just wasn't working any more. The air was very hot and stuffy — what little there was of it, that was. I looked around cautiously and saw that everyone else appeared to be suffering from this same shortage of air, all except Swanson, who seemed to carry his own built-in oxygen cylinder around with him. I hoped Swanson was keeping in mind the fact that the «Dolphin» cost 120 million dollars to build. Hansen's narrowed eyes held a definite core of worry, and even the usually imperturbable Rawlings was rubbing a bristly blue chin with a hand the size and shape of a shovel. In the deep silence after Swanson had finished speaking the scraping noise sounded unusually loud, then was lost in the noise of water flooding into the tanks.

We stared at the screen. Water continued to pour into the tanks until we could see a gap appear between the top of the sail and the ice. The pumps started up, slowly, to control the speed of descent. On the screen, the cone of light thrown on to the underside of the ice by the floodlight grew fainter and larger as we dropped, then remained stationary, neither moving nor growing in size. We had stopped.

"Now," said Swanson. "Before that current gets us again."

There came the hissing roar of compressed air under high pressure entering the ballast tanks. The «Dolphin» started to move sluggishly upward while we watched the cone of light on the ice slowly narrow and brighten.

"More air," Swanson said.

We were rising faster now, closing the gap to the ice all too quickly for my liking. Fifteen feet, twelve feet, ten feet.

"More air," Swanson said.

I braced myself, one hand on the plot, the other on an overhead grab bar. On the screen, the ice was rushing down to meet us. Suddenly the picture quivered and danced, the «Dolphin» shuddered, jarred, and echoed hollowly along its length, more lights went out, the picture came back on the screen, the sail was still lodged below the ice, then the «Dolphin» trembled and lurched and the deck pressed against our feet like an ascending elevator. The sail on the TV vanished, nothing but opaque white taking its place. The diving officer, his voice high with strain that had not yet found relief, called out, "Forty feet, forty feet." We had broken through.

"There you are, now," Swanson said mildly. "All it needed was a little perseverance." I looked at the short, plump figure, the round, good-humored face, and wondered for the hundredth time why the nerveless iron men of this world so very seldom look the part.

I let my pride have a holiday. I took my handkerchief from my pocket, wiped my face, and said to Swanson, "Does this sort of thing go on all the time?"

"Fortunately, perhaps, no," he smiled. He turned to the diving officer. "We've got our foothold on this rock. Let's make sure we have a good belay."

For a few seconds, more compressed air was bled into the tanks, then the diving officer said: "No chance of her dropping down now, Captain."

"Up periscope."

Again the long, gleaming silver tube hissed up from its well. Swanson didn't even bother folding down the hinged handles. He peered briefly into the eyepiece, then straightened. "Down periscope."

"Pretty cold up top?" Hansen asked.

Swanson nodded. "Water on the lens must have frozen solid as soon as it hit that air. Can't see a thing." He turned to the diving officer. "Steady at forty?"

"Guaranteed. And all the buoyancy we'll ever want."

"Fair enough." Swanson looked at the quartermaster, who was shrugging his way into a heavy sheepskin coat. "How about a little fresh air, Ellis?"

"Right away, sir." Ellis buttoned his coat and added: "Might take some time."

"I don't think so," Swanson said. "You may find the bridge and hatchways jammed with broken ice but I doubt it. My guess is that that ice is so thick that it will have fractured into very large sections and fallen outside clear of the bridge."

I felt my ears pop with the sudden pressure change as the hatch swung up and open and snapped back against its standing latch. Another, more distant sound as the second hatch cover locked open, and then we heard Ellis on the voice tube.

"All clear up top."

"Raise the antennae," Swanson said. "John, have them start transmitting and keep transmitting until their fingers fall off. Here we are and here we stay — until we raise Drift Ice Station Zebra."

"If there's anyone left alive there," I said.

"There's that, of course," Swanson said. He couldn't look at me. "There's always that."