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.