flew up about his legs. Abruptly he sat down again, his face ashen.

From the emergency 'chute opening far above a massive head appeared. "You all right, sir," Slashaway called, his voice vibrant with concern.

"Well, I—"

"You'd better come right up, sir. Captain's orders."

"All right," Lawton shouted. "Let the ladder down another ten feet."

Lawton ascended rapidly, resentment smouldering within him. What right had the skipper to interfere? He had passed the buck, hadn't he?

Lawton got another bad jolt the instant he emerged through the 'chute opening. Captain Forrester was leaning against a parachute rack gasping for breath, his face a livid hue.

Slashaway looked equally bad. His jaw muscles were twitching and he was tugging at the collar of his gym suit.

Forrester gasped: "Dave, I tried to move the ship. I didn't know you were outside."

"Good God, you didn't know—"

"The rotaries backfired and used up all the oxygen in the engine room. Worse, there's been a carbonic oxide seepage. The air is contaminated throughout the ship. We'll have to open the ventilation valves immediately. I've been waiting to see if—if you could breathe down there. You're all right, aren't you? The air is breathable?"

Lawton's face was dark with fury. "I was an experimental rat in the sky, eh?"

"Look, Dave, we're all in danger. Don't stand there glaring at me. Naturally I waited. I have my crew to think of."

"Well, think of them. Get those valves open before we all have convulsions."

A half hour later charcoal gas was mingling with oxygen outside the ship, and the crew was breathing it in again gratefully. Thinly dispersed, and mixed with oxygen it seemed all right. But Lawton had misgivings. No matter how attenuated a lethal gas is it is never entirely harmless. To make matters worse, they were over the Atlantic Ocean.

Far beneath them was an emerald turbulence, half obscured by eastward moving cloud masses. The bubble was holding, but the morale of the crew was beginning to sag.

Lawton paced the control room. Deep within him unsuspected energies surged. "We'll last until the oxygen is breathed up," he exclaimed. "We'll have four or five days, at most. But we seem to be traveling faster than an ocean liner. With luck, we'll be in Europe before we become carbon dioxide breathers."

"Will that help matters, Dave?" said the captain wearily.

"If we can blast our way out, it will."

The Captain's sagging body jackknifed erect. "Blast our way out? What do you mean, Dave?"

"I've clamped expulsor disks on the cosmic ray absorbers and trained them downward. A thin stream of accidental neutrons directed against the bottom of the bubble may disrupt its energies—wear it thin. It's a long gamble, but worth taking. We're staking nothing, remember?"

Forrester sputtered: "Nothing but our lives! If you blast a hole in the bubble you'll destroy its energy balance. Did that occur to you? Inside a lopsided bubble we may careen dangerously or fall into the sea before we can get the rotaries started."

"I thought of that. The pilots are standing by to start the rotaries the instant we lurch. If we succeed in making a rent in the bubble we'll break out the helicoptic vanes and descend vertically. The rotaries won't backfire again. I've had their burnt-out cylinder heads replaced."

An agitated voice came from the visiplate on the captain's desk: "Tuning in, sir."

Lawton stopped pacing abruptly. He swung about and grasped the desk edge with both hands, his head touching Forrester's as the two men stared down at the horizontal face of petty officer James Caldwell.

Caldwell wasn't more than twenty-two or three, but the screen's opalescence silvered his hair and misted the outlines of his jaw, giving him an aspect of senility.

"Well, young man," Forrester growled. "What is it? What do you want?"

The