EYES THAT WATCH

He, Sam Conway, was back from Mars now. Back from red, ferric deserts no Earthly boot had ever touched before. Back from bitter cold and aching dryness. Back from dazzling yellow hazes of dust and suspended ice crystals. No more need to wear oxygen armor in a thin, ozone-tainted atmosphere now. Back from solitude, and the endless fight to keep alive out there. Back from the enigma of Martian civilization's extinction, uncounted ages ago.... Back, back, back....

Home, now! From the window Sam Conway could see a row of maples, orange and golden in the autumn warmth. Kids were playing football in the street. Sam's oxy-hydrogen rocket ship, blued and battered and burnt, was suspended for all time from massive girders in the Smithsonian Institution. But even that was far away from Bryton, here. It should have been finished, now—the adventure. Sam Conway should have relaxed. Even Ellen Varney was beside him now. That should have helped. It did, a little. Yet only for moments at a time.

Those twenty months of exploration on another world, had become like a phantom in Sam's thoughts. Faded, distant, contrasting; yet starkly vivid too. Every hour had been a struggle. Extracting food substances from the tissues and juices of strange plants. Roasting native potassium chlorate in a small sun-furnace to extract oxygen from it, and compressing the precious gas into steel flasks. All this had been necessary, the dying Martian atmosphere contained only a low percentage of oxygen.

It had been a strange hand-to-mouth existence out there—a kind of game in which a fellow tried always to keep one small jump ahead of Death.

Hauling a crude little metal wagon, in which his supplies were packed, across the sand for miles and miles at a time, until his brain had reeled. Sleeping in a tiny airtight tent, when afield from his rocket.... Sam had never expected to survive those experiences. But he had, somehow; and it had done something to his soul—hardened it, and maybe killed part of it; and maybe beautified another part. For in spite of everything, those vast, ghostly solitudes of Mars were beautiful—

And there was more. Climbing the steep wall of an ancient artificial gorge not far from the south polar cap; gripping at odd prickly vines to keep from falling into the hardy thickets below, where tough-shelled worms crawled sluggishly, he had found something in a small, sand-drifted cell that was part of a ruin. Something that meant power.

What kind of power? All kinds, perhaps. Scientific learning greater than that of Earth. Power like that of gold and jewels, but far exceeding it. Power to wreck and to create, power to destroy worlds. Power, maybe, to sway minds. Sam still could not guess how far it might extend, or how deep—

No the adventure was not over, yet. It was just beginning. It wasn't just nostalgia that tied the consciousness of Sam Conway to a planet, millions of miles away, whose people had perished in a strange travail ages ago—a catastrophe whose marks lay in fused, glassy ruins, and in machines melted and rusted beyond recognition.

Sam had that secret of power hidden away now in a little aluminum box that had once contained concentrated food rations. And having that secret—though it thrilled him—still made him wish nervously that he also had eyes in the back of his head....

Ellen Varney's slim fingers tightened on his arm.

"Sam!" she said almost sharply. "You're dreaming again. What is it?"

He looked at her almost furtively, conscious of the familiar room around him, the old bookcase, the piano with a shaft of sunlight touching it gently; the radio and television cabinet. The colonial rag rugs, bright colored and homey....

Sam wondered wistfully if sometime soon his power would enable him to preserve in timeless youth the fragile beauty of Ellen Varney. Dark wavy hair, and an earnest face whose wisdom one could never forget. Maybe now even immortality would be possible.

Sam was nervous. Haste and preoccupation pressed him. But he put on a good show for the girl's sake. The lines of worry dissolved around his grey, deep-set eyes. He ran stubby fingers through his stiff mop of ash-blond hair, and the tightness of his lips and jaw relaxed into a sheepish grin.

"Sure I'm dreamin', Honey," he chuckled. "What man in my shoes wouldn't? Three years back I was nobody, working my way as a student engineer. Then Joe Nichols and his experts found out that my reflexes were better than those of anybody they'd tested. And that my brains and my emotional stability were okay. So pretty soon I was flying out there toward Mars—all for the glory of giving the Joe Nichols Food Products a publicity splurge. And now—well don't get the wrong idea of how I feel about it, Ellen—they've made a big-shot out of me. The newspapers, the radio, the scientists. I've got a lot to do. I—you know!"

Ellen Varney was perhaps sure she did know. She smiled faintly, like the Mona Lisa smiling at the naïveté of men, and their little-boy vanities. But there was a shadow of worry in her eyes, too.

"You won't stay here for supper, then, with the folks and me, Sam," she said wistfully. "Like old times...."

Sam couldn't think of anything nicer. But the pull of something else was much more strong.

"No, Honey," he said. "I—"

"Don't stumble, Sam," the girl returned. "Tomorrow night, then?"

"Maybe. I hope...."

He kissed her. A moment later he was out in the golden afternoon. He avoided the kids playing football out there in the street just as he used to play. He would have liked to talk to them. But—not now.

He climbed into his car. There he sat quietly for a moment, thinking. The autumn shadows, cast by the houses and trees, were long and blue. They reminded him of the shadows on Mars; and he felt a slight, not unpleasant, chill of loneliness and mystery plucking at his nerves. The sound of the wind wasn't so very different here either! Only out there it was shriller and much fainter and more sad, in the thin air, and through the muffling fabric of his oxygen suit.

Not so long ago Sam had seen those Martian winds shredding plumes of rusty red dust from the desert. He'd seen them blow balled masses of dried, prickly vegetation, like tumbleweeds, across the undulating red plain, and into the deep machine-dug gorges, all but waterless now, that on Earth were called the "canals."

He'd seen those dried bundles of weeds collected in rows against the granite masonry of walls that were cold and crumbled in their ancientness but which looked fused along their low crests, like old lava, telling a story of violent and enigmatic calamity.

Thus Sam Conway's reveries became unpleasant once more. He wanted to hurry again. He started the car, and drove swiftly out of the village. The tires crunched in dead leaves as he swung into the driveway that led down by the lake. Premonition must have been working in him, accentuating his caution and his haste.

There was a fair-sized brick building there, an old garage. He unlocked the heavy door and went inside. The large main room of the structure was to be his laboratory; the office, his living quarters.

He surveyed the dingy interior critically. Everything, so far as he could see, was exactly as he had left it except for a small smear of ash on the floor in the office room. Driveway ash. Part of a man's footprint. His own? With the panic of a disturbed miser, Sam Conway thought back carefully. It could be his own footprint; but he couldn't remember—couldn't be sure!

His heart began to throb in mounting anxiety at the thought that the lair of his secret might have been entered during his absence. He pulled the shades carefully. Then he clawed his way through the clutter of paraphernalia in the little room—mostly boxes of new laboratory equipment, as yet unpacked. And a few glass jars containing plant samples, and specimens of odd Martian fauna—souvenirs he hadn't been required to turn over to the scientists.

He was sweating profusely from panic when he reached the carefully fitted mopboard in the corner after pulling aside a small desk. He pressed part of the wooden ornamentation, and a section of the mopboard turned on hinges. Feverishly he drew his precious aluminum box from the hiding place he had contrived, and unfastened its lid. From within came a reassuring, cryptic gleam; and Sam Conway almost wilted with relief.

But he wasn't satisfied yet. His fear of possible burglary wasn't the result of miserliness alone. He was afraid to have so gigantic a secret as he possessed get beyond himself—yet. And he was well aware that man would kill to own what he owned—and distrusted, withholding it from Nichols and his scientists.

Carefully he put the aluminum container back, and searched the premises. The windows. The doors. Everything. But he found no telltale marks of intrusion. The footprints, then, in the office room must have been his own. But he'd bar the windows tomorrow. He'd put alarms on the entrances, and he'd find a safer place for his aluminum box.

Now he prepared to work, getting his notebooks ready, putting a little collapsible table in the center of the office room, securing the heavy wood shutters of the windows, turning on the lights, and taking the aluminum box, which was his storehouse of miracles, once more from hiding.

As he sat down at the table, he placed a loaded pistol within easy reach at his elbow. Thus prepared, he lifted his treasure from its homely metal container, and set it lovingly before him. A cube, perhaps four inches square. Like glass. Almost crystal in its transparency, except for a dim misting of pearl. Crowning the cube was a metal pyramid, much tarnished with age, and a dial. That was all. But Sam's gaze was almost gloating, as his mind filled with mighty visions of his own future. He was no different from any other man in this respect, for the touch of power was on him.

He turned the dial of the Martian apparatus. Within the cube spots of fire began to move, around and around a glowing center that was composed of myriad parts. It was all like a three-dimensional cinema—illustrating, in this instance, some mystery of the atom—its revolving planetary electrons, its nucleus of neutrons, positrons....

In a strange eight-fingered hand, which left the rest of its eon-dead owner's anatomy unpictured, a metal pointer was lifted, indicating this and that. It was like being in school on old Mars, whose people had been extinct for untold millions of years.... Maybe this apparatus, which held, in pictured, illustrated form, all the scientific lore of another time and world, had been a kind of school book.

Sam didn't understand much of this first lesson—yet. There were soft clinking noises—perhaps speech—which accompanied the fading, waxing, moving illustrations; but those music-box notes were perhaps forever beyond him as far as meaning went.

The atomic structure views were replaced at last by pictures of machines and apparatus—and that was a little better. Before his eyes Sam saw complicated pieces of apparatus taken apart and reassembled. He saw complicated processes actually carried out step by step.

Sam Conway's concentration was like a frozen hypnosis, and his brain was quick. But in the corners of the room there were faint shadows, and he was conscious of them. Still he took notes, and made drawings feverishly until the strain began to tell. Of course he could always refer back to the machine, repeating the views if necessary.

It was a month before he began to build. And then his first effort was only to produce a furnace and an alloy; the latter a product of the former. It was harder and more flexible than any steel yet produced. And it was worth money, providing the means to carry on his study and his work.

Work.... Sam seldom saw Ellen Varney now. He saw little of anybody. He told lies to be alone, and to continue his solitary efforts. His sense of struggle was like being on Mars again fighting for life, plodding through a thin feathery fall of snow there, in the dazing cold, close to the polar regions. And he dreamed of gigantic altruisms—the remaking of civilization.

In four months after his beginning, he had achieved things. Under a beam of specialized vibrations he saw a mouse do amazing tricks, its brain stimulated temporarily to an intelligence far beyond normal. It was awesome, and frightening too, watching that tiny animal turn—without error, and after it had been shown how only once—the complicated combination lock of a small door beyond which lay food.

Sam thrilled to the spectacle of the rodent laboring so keenly with its teeth and forepaws. What if the same waves were applied to the brain of a man? He would have tried those waves on himself, but his enthusiasm changed to dread when, with the removal of the beam, the mouse shuddered into a convulsion and died, its nervous system exhausted.

Biology revealed further mysteries and possibilities. In a glass flask, packed in a radioactive compound, and filled with water to which food substances had been added, Sam grew huge amoebae, whose ancestors had been microscopic. But these creatures were translucent globules, almost a quarter-inch in diameter. Somewhere here, perhaps, lay hidden the secret of life itself. But the amoebae died of a strange disease, the germs of which were perhaps generated out of those same life processes.... To be sure of safety, Sam poured sulphuric acid into the culture flask.

He changed his direction now, back to the atom. Eight weeks more, and he was ready for another test. The main room of the old garage was crowded with apparatus. Then, one night, Sam closed a switch cautiously.

The result was not much different than the shorting of a high-tension electric current across a broad arc. A snap. An avalanche of rattling blue flame, whose glare made everything look sharp and unreal. Then wires glowed to white heat and crumpled. A huge vacuum tube exploded into an incandescent puff of metallic vapors, superheated. The current was dead now—cut off. The experiment was a failure.

There were perhaps ten seconds like this—a sort of unsuspected bang—like that of a rifle cartridge whose defective primer cap fails to ignite the powder immediately when the firing pin strikes it. The garage interior was still illuminated, for the lights were on a different circuit. Smoke was blue along the raftered roof, and the red glow had faded from heated metal.

Then, at a moment beyond all expectation, a searing glare leaped out from between two close-pressed copper electrodes which had been the center of Sam's experiment. A wave of rays and heat, and stunning electrical emanations. Sam Conway's mind was far too slow for him to grasp just what happened. He only remembered a little when, battered and scorched, he picked himself up from the concrete pavement after a minute or more.

The points of the electrodes were shattered, but they still glared, incandescent, providing the only light now, for the light bulbs were shattered. Staring from aching, ray-reddened eyes, Sam saw only that glow, for he was temporarily all but blinded. But there were little pits in that hot copper—pits out of which the metal must have literally exploded.

The crackling continued—like a delayed explosion. His numbed brain sensed that something was terribly wrong.

He wasn't afraid right away. Not until his brain recalled did he realize. That bang, after his apparatus had burnt itself out, then that flash, or whatever you wanted to call it, was atoms breaking down more violently than they had ever done in the crude experimental atomic engines so far developed on earth.

Now there was another flash from one of those electrodes—just a tiny, incredibly brilliant speck—like a spark that flares and dies, failing to ignite tinder. Almost though. Almost an inconceivable conflagration, that might have spread and spread, from one atom to others.

Sam's sore eyes could see the broken roof now, and the springtime stars shining calmly through its splintered rifts. The sky itself was dimly luminous as with diffused light. Suddenly he was afraid of those stars, for they were like watching eyes; watching and inscrutable. And there was ozone—triatomic oxygen—metallically tanging in the atmosphere, mingled with the odor of burnt insulation. Sam wanted to leave the building, to go out into the night and cool his dizzied senses and his blistered body. Yet he had to keep guard to be sure to note anything further that might happen, for he knew what had just taken place.

Yes, he knew all right! Nature had been probed in its darkest lair by a clumsy hand. Nature had growled back threateningly. It had almost bitten. Almost...? Sam Conway's ribs seemed to shrink about his wildly pounding heart.

He leaned against the cracked brick wall, trembling. In memory he was on Mars again seeing those ruined buildings, sheered off, buried by the dust—smelling the metallic reek of ozone that had seeped back through the breath-vent of his oxygen helmet. Even as here, now. Ozone built up from the commoner form of oxygen by electrical discharges!

And by swift suggestion, Sam's thoughts went beyond Mars itself. Outside of the Martian orbit was the Path of Minor Planets—the asteroids. Broken up fragments. Perhaps a single world, once, that had been caught in catastrophe....

There was more, too. What were the rings of Saturn? What cataclysmic circumstance had made them? Atlantis and Mu, the lost continents. Why had they sunk beneath the sea, taking with them their splendid civilizations? And there were the novae far out in interstellar space; normal stars suddenly blazing forth in spectacular ruin. Yes there must be many other inhabited worlds in the universe, other folk, studying, learning to control and curb matter and energy. Sometimes knowledge must get dangerously ahead of itself, lacking a sound foundation of understanding. And then?

There was silence outside the building. So the crunch of hurrying footsteps in the cinders of the driveway penetrated easily to Sam's eardrums and excited nerves. A loud knock sounded at the outside door of Sam's sleeping room.

He staggered back from his ruined laboratory. From a small chemical cabinet he procured a flashlight. And he drew the pistol he always carried now, from his pocket, before he unfastened the heavy bar of the door.

It was Ellen Varney out there in the dark. Sam hadn't seen her in almost a week. He had never permitted her to come here when he was busy. To the rear, down the driveway, the headlamps of the girl's car made a white lantern-glimmer through the bushes.

For one frightening instant Ellen saw the pistol muzzle levelled toward her before Sam was able to recognize her and lower the weapon. But she didn't ask the reason for the gun at all.

"Sam," she stammered. "I couldn't sleep and I heard a funny, sharp explosion. It seemed to be in this direction. And when I looked out of the window I saw a glow in the sky—very faint. But it was in this direction too. I guess I had a hunch, so I drove out here. All the way I could smell ozone in the air. You can hardly see the phosphorescence in the sky from up close at all. But it's right over. What's wrong, Sam? What have you really been doing?"

The girl's tense fears, strong enough to make her come here, after midnight, to his laboratory, emphasized Sam's own private anxieties.

"I haven't been doing much, Honey," he told her hesitantly, and not too convincingly. "You'd better just run along home to bed. Research causes accidents once in a while. I'll get everything straightened out all right."

But in the reflected rays of the flashlight, the girl's face and eyes were determined.

"I won't go, Sam," she said very definitely, "until I find out that everything is all right. First place, you're hurt, and I'd be stubborn for your sake. But there's more. That glow in the sky. That smell of ozone—not only here, but everywhere here.... What does it all mean, Sam?"

Conway looked nervously toward the heavens. Yes, he could see a halo of light, sure enough. He had thought it was only the diffusion of starshine by the moisture in the atmosphere. Now he knew better. It was a little too bright and too low to be an aurora. It could be like an aurora, of course, something electrical and yet not quite the real, normal thing.

The breeze outside bore a slight yet unmistakable pungence of ozone too. It was just as Ellen had said. The gas was not only in the lab. It was here, too, as though all the atmosphere in the neighborhood had been affected by some electrical process.

"Listen!" Ellen said suddenly.

Sam strained his ears. At first he could detect nothing at all. Then he noticed a dim, lonely humming, that seemed to emanate from the ground, and from the bricks of the laboratory.

The sound seemed to be getting gradually louder. It made Sam shudder with the mystery of hidden things. And he began to feel, too, a sharp ache in his muscles, quite distinct from the soreness of his minor injury.

Suspicion grew on him again; suspicion that his latest experiment had been not entirely without lasting effect. Something had happened! Something had been started after all!

Sam grasped Ellen by the arm. "Come inside, Ellen," he said. "I've got to make a few tests."

He did this very quickly, working in the beam of his flashlight, which the girl held for him. Meanwhile he made a complete confession, telling her what he'd found on Mars and what he'd been doing.

He found now that he couldn't keep an electroscope charged. This meant that the air was ionized—that it would promptly conduct away any electrical charge that the instrument might hold. And atmospheric ionization meant, or could mean, the presence of radioactivity—of atomic disturbances.

He tried exposing a bit of photographic film in the dark. In the developing fluids it turned entirely black. There were strong invisible rays then, to affect it; rays coming from the walls, the ground, the very air itself perhaps. Rays probably from bursting atoms. The sound—the humming—must be some incidental phenomenon of their breakdown.

Dully Sam felt of the walls. Their temperature was already higher than that of the air and they vibrated distinctly with that steady hum. Sam's whole body felt hot, as though a strange flame was blazing in his own flesh.

He was sure, then. He had started a slow, progressive form of atomic disintegration in all the materials around him. In his own body too! It hadn't been the sudden fire of violent incandescence. That might have come. It had just been missed. The igniting spark hadn't been quite strong enough. Instead there was only a sort of smouldering. But, undeniably, atomic power was being released in a deadly, and uncontrollable if gradual, form.

The flashlight lay on the table shedding its white beam. Sam saw that Ellen's face was pale and her eyes glassy.

Sam had not the faintest idea of what he might do to check what he had started. "Get out of here, Ellen," he growled thickly. "Beat it! I've gone and tried to play God. And now hell's broken loose! Tell everybody to scram away from here!"

Very unsteadily the girl arose from the chair where she had seated herself. "I don't want to go, Sam," she stammered. "I can't leave you now."

He had to stumble forward then, to catch her before she fell. Her face was hot and damp with a weird fever. Her body had been affected too, by coming into the zone of influence. Sam Conway winced with an awful anguish as he picked Ellen up and tried to carry her toward the open door, and the safer night air outside.

It was only then that he realized how weak and sick he was himself. Strange rays were tearing at his nerves and brain. His very flesh was slowly—very slowly—giving up its atomic power, in a gradual radioactive decay!

He stumbled at his first step and fell crashing to the floor. Paralysis rushed over him, and that droning sound was like a death-dirge in his ears. He tried to drag Ellen's unconscious form toward the door, but the effort was useless. He couldn't even crawl. He just lay there, panting torturedly, his hot brain working in a chaos of fever. He understood now.

The death of Mars all over again. The fused walls. The melted machines. The ozone in the air. A slow, creeping smouldering destruction had burnt itself out at last; perhaps when a new balance had been reached in the atoms of the Martian crust. A crust. A cancerous disease moving in an irregular path, depleting air and water. But there still must be a tiny part of the old process of atomic breakdown continuing on Mars today, maintaining, by electrical disturbances, the ozone in the air.

And he, Sam Conway, had started that same creeping horror here on Earth. It would go along now, spreading and spreading. The walls around him would soon be melting. And there was nothing a man could do to stop it. Not even the science of Mars had been able to save the world that had given it birth. Only in scattered places where the erratic horror had not reached, perhaps in deep crevices in the rocks, had a few plants and low animals been able to survive for a new beginning after most of the fires had died.

Sam Conway cursed himself for his eagerness and lust for power. He'd been like an old gold miner, he thought savagely, ready almost to kill his own brother to preserve his secret until he could use it for himself. There were too many men like that. And now Ellen and all the rest of the world had to suffer.

Mu. Atlantis. The asteroids that had perhaps once been a plant, destroyed, maybe, by a much more violent form of atomic breakdown. But who knew just what accidents might have caused these respective catastrophes? Science must sometimes get ahead of itself, without even outside influence. There was always a risk.

Sam's mind began to fade out, toward the nothingness of oblivion.

Then the real miracle began to happen. The violence of it jarred his brain swiftly back toward a semblance of awareness. Suddenly everything around him was spouting blue electric flame. The table, the chairs, the walls, even the grass and trees beyond the open doorway rippled with a sort of aura. The phenomenon lasted for only two seconds. It snapped and growled like the first dash of some gigantic code signal. Then it broke off. Then it began again.

Once more it stopped. And started.

Sam, even had his mind been clear, could not have guessed how widespread the phenomenon was. He could not have known that, within a twenty mile radius fuses were blowing out, transformers were smoking in their oil-baths and generators were groaning under a terrific overload, as though their armatures had been gripped by an invisible colossus.

But Sam could guess some of the might of the new phenomenon. His body convulsed like the body of a condemned culprit in an electric chair as shocks ripped through him. He could not imagine the origin of what was happening now, unless the forces he had unleashed had entered a new phase of destruction.

Yet this did not seem to be true, for after the first spurt of unknown power had passed, that sonorous hum of doom had been completely strangled. Before the second spurt stopped there was a violent ripping explosion and the tinkling of broken window panes in the adjoining laboratory room. And that constricting paralysis and heat were gone from Sam's body. There were five bursts of strange energy, in all. Then it was over.

Prodded by sheer startlement Sam got to his feet and found that, in spite of weakness, he could stand. His brain was clearer, too. Ellen Varney, unconscious before, was trying to rise. He helped her up and supported her against him.

They stared out of the doorway at the sky. The auroral glow was gone. But they saw, for just an instant, a huge phosphorescent shape, hanging high against the stars. It was a little like a colossal image of a man, but it couldn't have been solid. It was like the aurora itself—as tenuous, as luminous—a kind of gigantic photograph projected in the air. The arm of the vapory figure extended; then the whole image vanished, as if at a speed far exceeding that of light, to some colossal distance.

Sam didn't even speak of the being right away. He helped the girl out of the building into the open.

"Wait here for a few seconds, Ellen," he said in a tone that trembled with awe.

Then he stumbled back into the old garage. All electrical devices were dead, even his flashlight. He had to find his way to the laboratory by burning matches. Every bit of apparatus was in fused ruins now, faintly reddened with heat. But there was no ominous hum in the hot, black stillness. Something deadly had been burned out of diseased substances by counter fire. Even Sam's own flesh had submitted to a curative force.

He found his way to one corner of the room, where, beneath a heavy block of concrete, he had prepared a new hiding place for his aluminum box, and the Martian demonstration apparatus it contained. Tugging the block of concrete free, he looked below it, lighting another match. Somehow the lid of the box had been blown off. Within, the Martian machine was the same as before, except that the crystal cube was no longer clear. Instead it was blackened all the way through, like a black diamond. And there were cracks in it that destroyed its usefulness forever. It, too, had been touched by those counter waves of energy. Touching the cube with his fingers, Sam found that it was hot.

He left the thing in its hole and returned to Ellen, his mind full of colossal realizations.

The girl's voice quavered with awe as she spoke there under the quiet stars.

"We had help, didn't we, Sam?" she stammered, remembering the cloud in the sky, and what Sam had told her about his work. "Somebody from another world. But who? Where...?"

"I don't know, Honey," Sam answered raggedly. "It wasn't Martian help. As far as I know, all Martians are dead. Besides, I've seen their bones. Manlike, but very slender. The being—pictured in the sky was heavily built."

Sam nodded significantly toward the sky.

"Lots of planets up there," he continued. "In other solar systems. Lots of different kinds of beings. I suppose some of those races, on planets of the older stars, have really grown up mentally and scientifically, till they know all about time and space and dimensions and energy, and how to handle and conquer them. And I suppose that somehow they keep careful watch across the awful distance because they've learned by experience that it may be safer. It's not just to save the necks of lesser beings but to guard themselves, too. I was messing around with something pretty big, Ellen. You can't tell how far a danger may sometimes go. A whole universe may be thrown into chaos—"

Sam's fists were clenching and unclenching absently. It was better for science to develop gradually, with a race. And even then there would sometimes be mistakes. Atlantis. Mu. The asteroids. Maybe some of the novae—

"We'd better get back into town, Sam," Ellen offered practically. "There may be damage done there—with all that's been happening. We'd better see."

A chuckle found its way through Sam Conway's awe. "Yeah," he said. "Like your car. I see the headlights have gone out. Good thing it's a diesel, with no electrical ignition to blow, and with a cartridge starter on the motor."

But Sam was too grateful over the miraculous escape from final tragedy he'd just witnessed, to worry much about damage suits over ruined electrical equipment.

And he was very grateful for Ellen, too. He might fly out to Mars some time again, or even farther. But when he touched the girl's warm shoulder he knew that he was truly home at last.