"Still rising," the diving officer said. "Still rising. Speed of ascent unchanged."

Swanson walked across to the diving stand and studied the slow movement of the depth-gauge dial. "How much fresh water left?"

"Thirty per cent."

"Secure blowing fresh-water ballast. Engines all back two thirds."

The roar of compressed air fell away and the deck vibration eased almost to nothing as the engine revolutions fell from emergency power to two-thirds full speed.

"Speed of ascent unchanged," the diving officer reported. "One hundred feet up."

"Secure blowing diesel." The roar of compressed air stopped completely. "All back one third."

"Still rising. Still rising."

Swanson took a silk handkerchief from his pocket and wiped his face and neck. "I was a little worried there," he said to no one in particular, "and I don't much care who knows it." He reached for a microphone and I could hear his voice booming faintly throughout the ship.

"This is the captain. All right, you can all start breathing again. Everything is under control, we're on our way up. As a point of interest, we're still over three hundred feet deeper than the lowest previous submarine dive ever recorded."

I felt as if I had just been through the rollers of a giant mangle. We all looked as if we'd just been through the rollers of a giant mangle. A voice said: "I've never smoked in my life, but I'm starting now. Someone give me a cigarette." Hansen said: "When we get back to the States, do you know what I'm going to do?"

"Yes," Swanson said. "You're going to scrape together your last cent, go up to Groton, and throw the biggest, the most expensive party ever for the men who built this boat. You're too late, Lieutenant, I thought of it first." He stopped abruptly and said sharply: "What's happened to your hand?"

Hansen lifted his left hand and stared at it in surprise. "I never even knew I'd been scratched. Must have happened with that damn door in the torpedo room. There's a medicalsupply box there, Doc. Would you fix this?"

"You did a damn fine job there, John," Swanson said warmly. "Getting that door closed, I mean. Couldn't have been easy."

"It wasn't. All pats on the back to our friend here," Hansen said. "He got it closed, not me. And if he hadn't got it closed — "

"Or if I'd let you load the torpedoes when you came back last night," Swanson said grimly. "When we were sitting on the surface and the hatches wide open. We'd have been eight thousand feet down now and very, very dead."

Hansen suddenly snatched his hand away. "My God!" he said remorsefully. "I'd forgotten. Never mind this damned hand of mine. George Mills, the torpedo officer. He took a pretty bad sock. You'd better see him first. Or Doc Benson."

I took his hand back. "No hurry for either of us. Your fingers first. Mills isn't feeling a thing."

"Good God!" Astonishment showed in Hansen's face, maybe shock at my callousness. "When he recovers consciousness — "

"He'll never recover consciousness again," I said. "Lieutenant Mills is dead."

"What!" Swanson's fingers bit deeply, painfully into my arm. "'Dead,' did you say?"

"That column of water from number 4 tube came in like an express train," I said tiredly. "Flung him right back against the after bulkhead and smashed in the occiput — the back of his head — like an eggshell. Death must have been instantaneous."

"Young George Mills," Swanson whispered. His face had gone-very pale. "Poor kid. His first trip on the Dolphin. And now, just like that — killed."

"Murdered," I said.

"What!" If Commander Swanson didn't watch out with his fingers, he'd have my upper arm all black and blue. "What was that you said?"

"'Murdered,' I said. 'Murdered' I meant."

Swanson stared at me for a long moment, his face empty of expression but his eyes strained and tired and suddenly somehow old. He wheeled, walked across to the diving officer, spoke a few words to him, and returned. "Come on," he said abruptly. "You can fix up the lieutenant's hand in my cabin."

"You realize the seriousness of what you are saying?" Swanson asked. "You are making a grave accusation — "

"Come off it," I said rudely. "This is not a court of law and I'm not accusing anyone. All I say is that murder has been done. Whoever left that bow-cap door open is directly responsible for the death of Lieutenant Mills."

"What do you mean 'left the door open'? Who says anyone left the door open? It could have been due to natural causes. And even if — I can't see it — that door had been left open, you can't accuse a man of murder because of carelessness or forgetfulness or because — "

"Commander Swanson," I said. "I'll go on record as saying that you are probably the best naval officer I have ever met. But being best at that doesn't mean that you're best at everything. There are noticeable gaps in your education, Commander, especially in the appreciation of the finer points of skulduggery. You require an especially low and devious type of mind for that, and I'm afraid that you just haven't got it. Doors left open by natural causes, you say. What natural causes?"

"We've hit the ice a few stiff jolts," Swanson said slowly. "That could have jarred it open. Or when we poked through the ice last night a piece of ice, a stalactite, say, could have — "

"Your tubes are recessed, aren't they? Mighty odd-shaped stalactite that would go down and then bend in at a right angle to reach the door — and even then it would only shut it more tightly."

"The doors are tested every time we're in harbor," Commander Swanson persisted quietly. "They're also opened when we open tubes to carry out surface-trimming tests in dock. Any dockyard has pieces of waste, rope, and other rubbish floating around that could easily have jammed a door open."

"The safety lights showed the doors shut."

"They could have been opened just a crack, not enough to disengage the safety contact."

"Open a crack! Why do you think Mills is dead? If you've ever seen the jet of water that hits the turbine blades in a hydro-electric plant, then you'll know how that water came in. A crank? My God! How are those doors operated?"

"Two ways. Remote control, hydraulic, just press a button: then there are manually operated levers in the torpedo room itself."

I turned to Hansen. He was sitting on the bunk beside me, his face pale as I splinted his broken fingers. I said, "Those hand-operated levers. Were they in the shut position?"

"You heard me say so in there. Of course they were. First thing we always check."

"Somebody doesn't like you," I said to Swanson. "Or somebody doesn't like the «Dolphin». Or somebody knew that the «Dolphin» was going searching for the Zebra survivors and they didn't like that, either. So they sabotaged the ship. You will remember you were rather surprised you didn't have to correct the «Dolphin's» trim? It had been your intention to carry out a slow-time dive to check the underwater trim because you thought that would have been affected by the fact that you had no torpedoes in the for'ard tubes. But surprise, surprise. She didn't need any correction."

"I'm listening," Swanson said quietly. He was with me now. He was with me all the way. He cocked an eyebrow as we heard water flooding back into the tanks. The repeater gauge showed 200 feet; Swanson must have ordered his diving officer to level off at that depth. The Dolphin was still canted nose downward at an angle of about 25°.

"She didn't need any correcting because some of her tubes were already full of water. For all I know, maybe number 3 tube. The one we tested and found okay is the only one that is «not» full of water. Our clever little pal left the doors open, disconnected the hand-operated levers so that they appeared to be in the shut position when they were actually open, and crossed over a few wires in a junction box so that the open position showed green while the closed showed red. A man who knew what he was about could have done it in a few minutes. Two men who knew what they were about could have done it in no time at all. I'll lay anything you like that when you're — eventually in a position to check, you'll find the levers disconnected, the wires crossed, and the inlets of the test cocks blocked with sealing wax, quick-drying paint or even chewing gum, so that when the test cocks were opened, nothing would show and you would assume the tubes to be empty."