The yellow gauge clicked with a tiny sound, and the oxygen tank went dry. The relay ratchetted slowly, automatically coupled on the next tank, and the needle on the gauge climbed to high-pressure again.

Bart Caxton watched the needle swing, and beads of perspiration rode high on his cheekbones. He twisted the metal mug in his hands, and his voice was ragged with welling emotion.

"Three weeks," he said viciously. "And we're five weeks from the shipping lanes. There isn't enough oxygen to carry us back."

"Shut up!" Tom Headley's tone was thin with suppressed anger. "All the damned talking in the world won't change things. We've got to land now, have got to find the kronalium , or we'll never get back."

He leaned against the wall, searching the cloud-shrouded ground below the ship, feeling the uneven drumming of the rockets driving the ship forward. Nerves crawled his back, and sweat slimed his hands. He shuddered, imagining the horrors that might lie below.

The mug banged against the floor, and Caxton was standing, half-crouched, his heavy face set and stony, his hands riding the butts of his twin dis-guns.

"I say we go back," he snarled through set teeth.

Headley laughed, and the sound was the only thing that could have broken the tension of the moment. He tilted his head and laughed until the tears ran from his eyes; and slowly the rage faded from Caxton's face, and his shoulders sagged in weary futility.

"Okay, you win," Caxton said sullenly. "I know I can't force you to turn around, since you're the only one of us that can recognize and work kronalium for the stern jets. But," and his eyes were swirling pools of flaming hate. "When we do get back, I'm going to blow a hole through your back some night."

Tom Headley turned away, the fear piling in his mind until it was a choking cloud that stifled all thought.

" If we get back," he said dully.

He slid his hands over the control panel, adjusting the studs and levers with a delicate familiarity, striving to bring another ounce of power from the single rocket-bank that still functioned. But there was only the uneven beat of the rockets vibrating the floor as they had done for three days now, and no adjustment of the controls could make them function better.

Bart Caxton sat again, fumbled a cigarette from his pocket, then dropped it to the floor. His face was white beneath its tan, and there was a haunted desperation in the tightness of his bulky body.

"How long will it take?" he asked. "Will we make it back to Earth before—" His voice thickened. "—before we smother to death?"

Tom Headley shrugged. "It'll be tight," he said slowly. "We'll be on half oxygen-rations the full trip back. But it can be done; I went three months on half-rations once—and then got drunk on Earth's air for two days after I landed."

"To hell with you and your fancy trips!" The madness was building again in Caxton's mind. "You've been everywhere—but you ain't been here ; you don't know what Uranus is like, nobody does."

He lunged to his feet, pressed close to the port. His breath clouded the quartzite pane, and he polished the glass impatiently.

"Look at that," he said thinly. "That's the place we were going to explore; that's the place where it is so cold and the pressure so great, air collapses and can't be breathed. We were going to do what the early explorers failed to do; try to find life and minerals. They failed because their space suits could not stand the cold. Now we'll be marooned there because a damned meteor busted our stern rockets all to hell!"

"Don't blame me for that," Headley said, and instantly regretted the words.

" Okay! " Caxton spun back to his seat. "I let the force-screen die for a couple of hours while I slept. But don't think I'm taking the blame for the whole mess, even at that. This was your screwy idea."

Headley nodded. "If we succeed, our reputations will be big enough to gain us backing for almost anything." He grinned, and some of the fear was gone from his mind. "Hell, what if we are cooped up here for a few days? I'll fix the rockets, we'll do a bit of exploring, and then high-tail it back for more oxygen. We'll live in vac-suits and save our air; and the suits hold enough rations to last us for three months."

"And if the rockets aren't fixed?"

Tom Headley forced the thought from his mind. "They'll be fixed," he said quietly.

Bart Caxton slumped into a sullen silence, his slitted eyes watching the profile of his companion. Slowly, cunning crept into his face, and his right hand slid along his thigh toward one belt-gun.

"I wouldn't," Headley said without moving. "You can't fix the ship, and help won't be sent for us for at least three months. A man couldn't live that long, on the oxygen we have left, I don't believe."

"I might make the oxygen last for me until I got back to a regular traffic lane."

Headley swung about, and anger paled his face. "Damn it, Caxton," he said brittlely, " we'll get out of this! Probably, because of the pressure and cold on the planet, we'll find frozen air which can be thawed out; we'll look for it along with the kronalium ." He watched the stillness of his partner's hand. "Murder won't solve anything!" he finished softly.

Bart Caxton nodded slowly. "Sorry, Headley," he said. "It's just that I've never been in a jam like this before."

Tom Headley grinned. "We'll see it through—together," he said.

"Okay!" Caxton's tone was sullenly agreeable, but small fires of cunning still swirled in his eyes.

"Get ready for a shock-landing," Headley said relievedly, reached for the controls.

The icy wind roared like ten million furies about the grounded ship, sucking up the powdery snow, smashing it against the gleaming alumisteel hull. Great boulders of snow and ice tumbled playfully about the rubbly landscape, splashed in foamy explosions into the semi-frozen pools of liquid that dotted the planet's surface.

Tom Headley shivered involuntarily, turned back from the port.

"Colder than the hinges of hell out there," he said worriedly. "I can understand how the first crude vac-suits couldn't stand up for very long."

"Yeah!" Caxton glanced up from sealing the zipper slit at the front of his suit. "I only hope these suits can take it."

"They can; they're made for absolute-zero work in space. Here, the only trouble lies in the super-gravity and the wind. Either might rupture the outfits."

Caxton watched snow pile against a huge boulder, then saw it whisked instantly away by the force of the wind. He glanced at his vac-suit against the wall, and fear rode the sullenness of his eyes.

"Who's going out to do the exploring?"

Headley smiled from where he tugged on his suit. "Both of us," he said cheerfully. "We'll stay together with a shock-line; then if one of us is injured, the other can help him back to the ship."

He shrugged his shoulders into the suit, closed the air-tight zipper. Caxton turned slowly, lifted his suit, carefully fitted it to his stocky body. His fingers shook slightly, and his face was white.

Tom Headley watched his partner silently for a moment, then shrugged and checked the oxy-cylinder pressure-gauge. The needle pressed tight against its rest-pin. He lifted the glassite helmet, swung it idly in his hand for a moment. He knew the grimness of the moment, knew that the tank on his back held less than six hours of life-saving oxygen. When that was gone, if he were not back at the ship, he would die. A wry smile lifted the corners of his mobile mouth. Within the suit were enough concentrates and vitamin capsules to last him for months, and a special apparatus made it possible for water to be drawn from the air he breathed. He grinned at the thought; without air, the rest was superfluous.

"Okay," Caxton said finally, "let's take a look." He slipped on the helmet, cogged it to his shoulder-plates, left the visi-port open. Cunning still burned in his eyes, and his gaze dropped when he caught the full impact of Headley's distrust.

Headley locked on his helmet, cogged the port shut, tested his radio. Caxton answered shortly, shut his visi-ports and both turned to the entrance of the ship.

Metal squealed beneath Headley's hands; then the cogs were loose. Headley braced his shoulder against the port, strained mightily, was joined by his partner. Together, their strength was sufficient to force the door open against pressure of the air outside.

The air gushed in with incredible force, shoved the men forcefully against the metal wall, then subsided as the pressure was equalized. Headley stepped forward, felt the icy crystals of snow tapping against his suit. He thrust one arm through the port, gasped, as gravity jerked it groundward. He leaned back, sighed. Inside the ship, with its inertia-stasis gravity, normal movement was possible; but outside, with the super-gravity, even slow walking would be a job.

"Set your suit control for three graves," he ordered. "That way, we'll have enough weight to stay on the ground, and will still be able to move."

Bart Caxton growled an unintelligible reply, drew his right arm from the semi-rigid sleeve of his suit, made an adjustment on the suit's control-panel. Instantly, weight descended with pile-driving force, and muscles corded in his legs to counteract the tripled gravity.

Headley adjusted his gravity control, then connected himself to Caxton with a ten-foot length of cable. Carefully, he lowered himself from the port, stood erect in the howling wind and snow, waited until Caxton had clambered down to his side. Reaching upward, they closed the port, leaving it uncogged, so that they could easily reenter.

Headley checked his radi-compass bearings, then braced the full force of the wind, Caxton pressing forward at his side. They struggled toward the ice-sheathed cliff a hundred yards away, each step an agony of effort, clumsily dodging a huge boulder that rolled a lazy path of death toward them.

Snow smashed at them, made vision difficult, went whirling away. Even through the radi-heated layers of their suits, they could feel the implacable cold plucking at their lives with skeletal fingers of death. Minutes passed, as they fought through the drifting snow, each minute an age of effort; and when Headley glanced back, he felt a vague surprise to find that they had travelled so short a distance. He grinned at Caxton.

"Like trying to run in a slow-motion dream," he said, frowned slightly when he heard his partner's sullen growl of acknowledgment.

They struggled forward again, approaching the cliff of ice and rock that towered overhead. Headley splashed heedlessly through a small pool of semi-liquid, halted with a tiny cry of excitement.

"Look!" he said. "That rock's alive."

Bart Caxton tilted his gaze to where several clay-colored rocks lay at the edge of the pool.

"You're nuts," he said. "They're just rocks."

"I'll swear I saw one move out of the way of my foot," Headley insisted stubbornly, bent and lifted the first of the rocks.

It was heavy in his hands, and he had the uncanny sensation that it squirmed impatiently as he lifted it. He examined it carefully, ignoring Caxton's impatient words for them to hurry. And even as he watched, he saw the living rock split in his hands, opening down the side, disclosing gill-like fringed flesh that looked like slivers of whitish ice.

" It is alive! " he exclaimed excitedly, then dropped the stone as sudden giddiness clutched at his senses.

Caxton caught at his drooping body. "What's wrong?" he snapped.

Headley blinked his eyes. "Nothing!" he disclaimed. "Just a combination of pressure and lack of oxygen." He reached for his suit's panel, opened the oxygen valve another quarter turn.

He shook his head slightly, then bent to study the rock he had dropped. It had not moved, nor had its mouth-like opening closed. It lay at his feet in the shallow liquid, resembling nothing more than a ruptured rock.

"To hell with it!" Caxton said disagreeably. "Let's find the kronalium ."

Headley nodded, stumbled after Caxton. But jubilation was in his heart. When he and Caxton returned, they would take back several of the rock-creatures as living proof of the success of their mission.

He glanced back, saw squat legs flick from the opening in the rock, saw the creature scurry back to the few others of its kind that rested at the side of the semi-frozen pool of liquid. He grinned again, then pressed forward to lead the way to the cliff.

They rested in the lee of the escarpment, safe from the howling wind, huddling out of the way of the rocks and snow-clots that went spinning by from the fury of the storm.

"Now what?" Caxton asked.

Tom Headley glanced at the gauges below the level of his chin, watched the needles carefully.

"God!" he said. "This place is a storehouse of minerals and elements. We'll have no trouble getting money for an expedition."

"Damn it!" Rage knotted Caxton's voice until it was a thin screech. "Who cares about that; do you find any traces of kronalium ?"

Headley watched a single dial, turned slowly, studying the line of cliff-base at his left. "Close by," he said. "It must be a big deposit, for the needle doesn't waver."

"Then let's get to it!" Caxton came to his feet, towered over his squatting partner.

Headley struggled upright, fighting the super-gravity, led the way down the edge of the escarpment. Time and again, he fell, tripped by the gravity, whirled aside by the smashing wind. Each time, he struggled erect, forced himself to go forward again.

He watched the needle floating in its case, followed its point unerringly toward a shallow recess in the cliff's base. Using his belt pick, he chopped at the layer of ice and snow, let out a shout of relief when a strip of reddish metal appeared.

"This is it," he announced. "Now the repair job will be simple."

Bart Caxton nodded, seeing the metal, and for a brief second his hand hovered over the single gun strapped to his suit. Then he relaxed, caught his pick in his right hand, bent forward to help smash away great chunks of the metal.

"It's almost anticlimactic," he said shortly, "finding this stuff so easily."

Tom Headley grinned. "It would have been more anticlimactic," he said, "not to have found it. I've found traces of it on every planet I've visited."

Then they worked without further conversation, digging loose a great pile of the metal, making staggering trips to the ship with the precious element that was the only metal with which their rocket tubes could be repaired. Hours later, they cogged the port shut on their ship, exhausted the tainted air, released a breathable atmosphere.

Out of their suits, they ate a quick meal, began the task of smelting the kronalium so that it would fit the wrecked drive mechanism at the rear of the ship. Headley worked with the quiet sureness of a man whose life had been self-sufficient; Caxton worked with the grim doggedness of a man who knows that his life hinges upon his speed in working.

They worked in shifts, eating and sleeping when they could, Caxton doing the crude work, Headley putting the final touches upon the delicate task that was theirs.

And forty hours later they stood in admiration of the job they had done. New metal tubes glowed redly in the light of the radi-lamps, ready to send the ship hurtling back toward inhabited space. They still sparkled from the heat generated when Headley had given them a trial burst of power.

"And that's that," Headley said. His face was grim and lined, and his smile was a trifle forced.

Bart Caxton nodded, but his eyes were on the bank of dials that indicated the quantity of oxygen still aboard the ship. His lips were thin, and his eyes blank, as he made swift calculations in his chaotic mind.

"Let's blast off," he said.

Tom Headley grinned. "Not yet," he said. "There's five hundred pounds of kronalium back there that we're taking along. And I want several of those rock animals for living proof that we've been here."

Anger distorted Caxton's features. His hand sought the gun at his waist, then dropped beneath the steadiness of Headley's gaze.

"All right," he agreed sullenly. "But let's hurry."

Five trips they made, carrying the metal back to the ship, knowing that each trip made them more wealthy, so scarce was the metal in great quantities.

And then, on the sixth trip, Caxton snatched the single gun from Headley's waist. He laughed as he did so, and the sound was thin and strained with triumph.

"It's you or me, Headley," he snarled. "And I figure it's going to be me."

Headley felt horror welling into his mind, but he forced his voice to be absolutely calm and unemotional.

"Don't be a fool, man," he said. "Both of us can make it back, by going on short oxy-rations."

Caxton shook his head. " I'm going back," he said viciously. "I'm taking the ship, the kronalium , and a couple of those damned animals for evidence. I'll say that you died on Uranus." His voice was suddenly flat and deadly. " Sucker! "

A cone of blackness flared from the gun in his hand, caught Tom Headley, dropped him in his tracks. He twitched silently, lay where he had fallen, his right arm splashing liquid from the tiny pool at his feet.

A cone of blackness dropped Headley in his tracks.

Bart Caxton tossed the gun aside, leaned over, unscrewed the hinged valve on Headley's oxygen tank, then callously dumped the unconscious man into the pool.

Then, without another glance at the body submerged in the pool, Caxton caught up three of the living rocks, turned and fought his way back to the ship. He stood for a moment in the ship's port, staring bleakly at the pool where the dying body of his partner lay. Then he slammed the port, cogged it shut.

He laid the rock animals in a dark corner of the tank room, then walked heavily back to the control room and removed his suit. Grinning, he sank into the pilot's seat, and his hands raced over the controls.

Rockets drummed, and the ship fled into space on a tail of flaming gasses.

Bart Caxton watched the gauges, then reached out and adjusted the oxygen valve. He would have to go on three-quarters' rations, but there would still be oxygen left when he struck the spacelanes.

And back on Uranus, Tom Headley stirred out of his unconsciousness. He gasped, struggled to his feet. Metal banged on his shoulder, and a reaching hand found the opened valve. He instinctively screwed it shut, dull horror and terror piling in his mind.

He knew that he had but seconds to live, and the utter futility of his predicament made the situation even more horrible. True, he had his radio—but its range was less than a hundred miles; it would bring rescue only if a rescue party landed. He laughed a bit, grimly, ironically, remembering the great supply of food tablets that were in his suit. All that he lacked to live was air.

Then he frowned, seeing the oxygen gauge in his suit. The needle pressed tight against its stop-post. He tapped it, then checked another gauge. And sudden understanding came to his eyes—and he fought against the hysterical laughter that filled his throat.

Bart Caxton had failed in his murder attempt.

For Tom Headley's shoulder tank was full of liquid oxygen. He had fallen into a pool of oxygen, liquesced by the tremendous pressure of Uranus, and the pressure of the atmosphere had forced the oxygen into his tank.

Now there were but the interminable weeks of waiting that were to come before a rescue expedition was sent to save him.

And on the ship speeding back to the spacelanes, Bart Caxton clawed at his shirt collar. He gasped, trying to get oxygen from the dying air. He read the gauges with incredulous eyes, then came to his feet and lurched down the corridor. He swung through the door of the tank room, swayed there, his eyes straining into the semi-darkness.

And a terrible scream ripped at his constricted throat. For he knew then the thing that Headley would shortly discover. The pools of semi-frozen liquid on Uranus were of liquid oxygen—and the animals in those pools lived on pure oxygen.

Even as he watched, one animal turned from the last tank of oxygen, ran frantically about on short legs, then collapsed, its split mouth gaping in death.

Caxton screamed, felt nausea cramping at his body. He remembered then the liquid into which he had rolled Headley's body, and he knew the other man would live to see Earth again. And he knew then that the animals in the ship had used in minutes the life-giving gas that should have lasted for days.

And even as he screamed, he fell. And the last sight he had was of the rock-animals' split mouths laughing at him and his plans in an awful mocking silence.