> > SOMETHING FROM JUPITER
> > by
> > Dow Elstar
> > [pseudonym of Raymond Z. Gallun]
> > Cover story of the March 1938 issue of Astounding Science Fiction
> > Cover by H.W. Wesso
> > Illustrations by H.W. Wesso

> > I.

> > GREGORY CROSS might have escaped the weird compulsion of the thing by racing back toward his laboratory. But he did not do so.
> > Why? Hope was the cause — hope backed up by grim, fearful necessity. He had been born on an Earth whose people seemed doomed to extinction by a Sun that shed three times as much heat and light on his native planet as it should have.
> > Forty years ago the catastrophe had begun. A tremendous cloud of meteoric refuse had drifted into the solar system from the interstellar regions. Quickly the cloud had been drawn into the Sun, adding to its bulk and stirring up its fires.
> > The increased solar mass meant increased solar gravity, which tugged more powerfully at the encircling worlds, narrowing their orbits, and drawing them closer to the central holocaust. The changes which had taken place in the Sun, unlike a passing noval explosion, were permanent.
> > Earth had become an alternately parched and scalded waste, to which a few humans still clung, doggedly, and with full knowledge that, barring miracles in which they no longer believed, their extinction was decreed.
> > But hope, even in the blackest of circumstances, is an emotion that is easily aroused. Thus Gregory Cross looked out into the hot, steamy night with a strange exultation thrilling his pulses. Might he not find, in the science of another planet, the means to help his people?
> > Five minutes ago he had seen the missile trace a glowing, meteoric path through the atmosphere. But its speed had been swiftly checked by something more effective than mere friction with the air. It had landed, almost lightly, like a half-deflated balloon, five hundred yards away, where the hills loomed up toward the murky stars and gathering clouds.
> > Gregory Cross could not truly have said that he knew what the thing was; yet he was aware of its origin. Not without results had he been receiving and sending code signals impressed on a fine vibration of the ether, differing in no respect from the all-pervading cosmic rays of space. By the representation of simple forms and pictures in a graph-type code, he had been able to teach the unknowns across the void a slight knowledge of English. From their crude, uncertain messages, he had been able to grasp a hazy idea of some vast need which was theirs. The sensitive, movable coils of his direction-finders had told him beyond question that the messages came from, or from the vicinity of, the planet that now gleamed dully in the south. It was Jupiter, a world with physical characteristics as different from those of Earth, as the vacuum of space differs from the ocean deeps.

> > ***

> > FOR three weeks now, Cross had been receiving a series of dot-and-dash signals which spelled over and over again a single word: "Coming! Coming! Coming!" And so he was not too surprised that this promise of alien visitation had become fact.
> > The compulsion of the thing was new to him, however, and suggested sinister elements. It was not like the compulsion of hypnotism. Rather, it was as though some invisible impulses were clutching at the motor nerves of his body, urging his legs to move at a rapid run toward where the missile from far beyond Terrestrial boundaries had landed.
> > And though he felt the icy touch of terror at this demonstration of eerie neurotic science, he made no effort to resist its call. Forward he hurried, allowing his limbs to function under the commands of a mind other than his own, wild hope overbalancing his fears.
> > And so, presently, he stood before the missile. There were occasional rumbles of thunder now, and flashes of lightning. By the brief flickers of illumination, he saw what the object was. It was a sphere, gray and dusty in hue, like the parched and lifeless soil under his feet. This strange Something from Jupiter was covered with the oxide of metal burnt in the frictional heat of swift passage through the atmosphere. It still exuded a reeking, cindery warmth, and within it there were faint, whispering, clicking sounds of contraction.
> > For a minute Gregory Cross stood motionless in the weird night, waiting for whatever was to happen next. In that minute the wind rose out of the stillness, making a sad, lonely whisper across the sky, and causing his ragged shirt to whip about him. A few big, scalding raindrops plopped in the dust at his feet. Others struck the sphere, and hissed into puffs of steam. Once, Greg Cross glanced back toward his isolated laboratory, whose steel roof, fitted with vacuum compartments as a protection against the awful solar heat, hunched like a dim monster in the gloom.
> > Then, with scarcely a sound, the great globe broke into halves like a clamshell, its hemispheres still hinged together, their dividing faces turned upward.
> > This event, however, offered little in the way of revelation. There was a hollow space at the center of each opposing hemisphere; and though the thick metal all around might hide intricate mechanical complexities, nothing of it could be seen.
> > Greg half expected to hear tinkling bell-like notes beating out a few words in code, but none came. None, in fact, were needed. For the weird compulsion supplied all the commands that were necessary. Now that Greg was so close to this alien fabrication, the compelling impulses it emitted were far too strong for any human will to resist.
> > With a kind of dull resignation, he watched his feet step within the hollow of one of the hemispheres. Like one carried along impassively by some one else, he felt his body double itself up into an embryonic position in the cavity. Then the other hemisphere folded over upon him like a lid. Infinite darkness enveloped Gregory Cross. The sounds of the rising storm were blotted out as if turned off by a switch. For many minutes the silence endured.

> > ***

> > BUT THEN there was a sense of sudden movement — sudden thrusting, crushing, upward motion — mingled with the thin, muffled scream of speed-tortured air.
> > "Going to Jupiter," Greg thought vaguely. "I'm going to Jupiter!"
> > And his mental processes rushed on, elaborating and straightening out his scattered ideas: "This globe must be guided and operated by remote control," he muttered. "It has to be, because evidently, I'm the only living thing inside it— Jupiter, huge and cold— No man could live there for a second without artificial aids. Yet it has people — intelligent people! Wonder what they're like? Wonder what they want with me? The word 'help' was in many of their messages. But what sort, of help do they need? And how could a Terrestrian aid them, anyway?"
> > Greg thought of the compulsion that had gripped him. It was gone now, but a placidity, a fatalism that deadened worry remained. He could move his limbs freely within the limits imposed by the metal walls around him. But then, of course, here inside this tiny space there was no necessity to maintain the commanding spell over his nerves and muscles. He was effective and completely a captive without the compulsion.
> > A captive? There was no reason to suppose that any bond of real sympathy might ever exist between the dominant life-forms of two utterly different worlds. He was being transported to some almost unimaginable hell. He'd never see Earth again! Aid for his own people from another planet. Bah! It had been insane even to hope!
> > He felt cold. His body tingled with a thousand electrical prickles. His senses were dimming. Was the coma he was falling into suspended animation or real death? His thoughts were blotted out in growing twilight—

> > II.

> > GREGORY CROSS' first sensation, on awakening, was one of crushing weight. He was lying on his back on some hard and slightly curved surface. There was a fluid wetness around him, and he heard a gurgle like that of water going down a drain. Mingled with this sound, there was a distant and mighty soughing, like that of some tremendous tempest. Greg had no remembrance of the passage of time. He could not know whether months, or only hours, had gone by since he had last been conscious.
> > What he saw when he opened his eyes was not exactly a room. Rooms were rectangular, while this compartment was spherical. It was perhaps ten feet across, enormously braced. It was bare of appointments except that, from the domelike curve above him, complicated grids hung suspended, almost touching his face. There was a fading heatless glow, reddish and dim, in those grids. Through small holes near Greg the last few quarts of some kind of liquid was draining. It seemed that recently the entire compartment had been flooded.
> > Greg crept tediously out from beneath the grids. "This is Jupiter," he thought dully. "This is the prison that they — the Jovians--have locked me in."
> > Oddly, he wanted to laugh. But he checked the impulse, knowing that in that direction lay hysteria and madness.
> > He looked at the arcing sides of the globular chamber. Its walls were translucent, and through them an eldritch, flickering light sifted, now bluish, now gray, now savage, dazzling white. That flickering illumination was like lightning. The crashing rumbles that went with it, blending with the muffled and vibrant howl of a Jovian hurricane, could be thunder.
> > Presently Greg discovered the nature of the translucence of the walls around him. They were meant to be transparent, but on their inner surface a rime of whitish crystals was forming. Frost? Probably, for the cold out there beyond this compartment must be terrific. Funny that he didn't feel cold. Just comfortable instead. It was all rather puzzling. Guessing the truth was still a bit beyond him. He could not know that that frost — that congealed, Earthly water — had recently been part of his own flesh!
> > "Hello!" he shouted. "Where is everybody?" His voice echoed loud and brittle and strange in the narrow confines of the chamber.
> > There was no answer, other than a soft rustle beyond the wall, down low and to his right. Greg scrambled to the place whence the sound seemed to issue and with his fingers tried to loosen a little circle of the frost. It felt almost hot to his touch. Yet he did not speculate upon the incredible implications of this fact now. For there was something else to hold his attention.

> > ***

> > THE FROST rubbed away, revealing a crystal-clear substance beyond. Before the latter was filmed over with ice crystals again, Greg saw, through the thick, transparent substance, a half dozen gray-white arms, which seemed almost as fragile as pipestems. Lightning flickered beyond the creature to which they belonged, glinting on its queer body with reflected sparks of cold fire, like a mass of opaque ice sprinkled with the dust of tarnished silver. Little, suckerlike discs, terminating the boneless appendages at the ends of the arms, flattened against the glassy material.
> > Savagely, moved by mingled fascination and horror, Greg Cross scraped the frost away from his little spy window once more. Eyes confronted him now — three eyes that glinted at him like the highlights on a glossy stalactite at the other side of a dark cave. They looked like faceted bits of diamond, behind which burned an intense, purposeful thought. Deep in horny hollow of an odd, whitish-gray exoskeletal armor, those orbs were set. Over each were bright, red markings which Greg was to remember.
> > The monster was clearly not meant to walk erect like a man, but to crawl with its short, flat body in a horizontal position, like that of a millipede. Yet there was a distinction between its numerous arms and legs. The latter were at the edges of its under surface, while the former sprouted in a cluster from the center of its back. Its mouth was a ragged, toothless orifice beneath its eyes, surrounded by tufts of thick hair whose icy sheen suggested that the flesh from which it projected was far different in function and chemical constitution from anything remotely resembling it that could belong to Earth.
> > Gregory Cross shuddered. There, beyond the transparent wall, was a Jovian demon which, though it resembled certain Terrestrial creatures in physical appearance, still must belong to a different life-order entirely. Whatever fluid flowed in its tissues could not even have water as its base, here in the withering cold of Jupiter. Ammonia gas, liquefied by the great pressure of an atmosphere thousands of miles deep, perhaps served as water in the flesh of this weird devil.
> > Greg was conscious of the dramatic import of this moment. Two cultures, represented by the Jovian and himself, were meeting for the first time in history. A gap of interplanetary distance had been bridged. Yet that gap was nothing compared to the immeasurable gulf made of a thousand differences of environment, tradition, and need. He felt more forcibly than ever before the immensity of those differences. And so, now, his only feeling for this monster of Jupiter was cold horror and suspicion.
> > Yet he was gripped by a sudden need to do something — anything — to steady himself. And so he began to whistle in short and long bursts to indicate the dots and dashes of their simple code language.
> > "You are a Jovian," he spelled, just as he had often done back on Earth, when his only contact with these weird folk was through the medium of his cosmic ray generator and detector. "I am a Terrestrian. Terrestrian — Earth. Jovian — Jupiter. Jovian said — Terrestrian help Jovian. How?"

> > ***

> > PAST experience must have enabled the being beyond the frostless spot in the transparent wall to understand what was wanted without special difficulty. A reply, however, considering the utter crudity of the only available means of communication, was hard indeed to accomplish. Nevertheless, as in the past, the Jovian made an attempt.
> > Dimly, through the wall, Greg heard buzzing vocalizations of code: "Terrestrian help Jovian. Jupiter moon— Jovian as Terrestrian—"
> > There was a pause. Gregory Cross might have gotten something out of these words in time. But his conclusions could have been only the vaguest of guesses, at best.
> > Then the gray-white devil seemed to have an inspiration.
> > "Terrestrian look Terrestrian!" he buzzed rapidly. "Terrestrian look Terrestrian!"
> > Greg's puzzlement over what was meant was only momentary. He looked down at himself, as he judged he had been commanded to do. During the first second of his scrutiny, he saw nothing unusual — but this was only because the flickering, uncertain light had tricked him a little. Then he saw the truth. His own arms and hands were gray-white, like ice and silver dust! This shade matched almost exactly the shade of the Jovian's own flesh! Even Greg's clothing had been transformed, the fabric of it changed to complex compounds belonging to a different order than its original synthetic-cellulose composition!
> > Part of Gregory Cross, the emotional part, was stunned. Yet his reasoning powers, for a few seconds, seemed to reach the keenness of sheer wizardry.
> > He saw part of the mystery, all at once, and almost clearly. How long had he been in Jupiter? A long time, evidently, for the minute observations which must have been a necessary preliminary to his transformation could scarcely have been made in a hurry. All the while that he had been in a state of suspended animation, since his arrival on Jupiter, these grotesque beings had been studying the structure of his body, and the nature of his metabolism!
> > At last, here in this spherical chamber, frigid fluid had enveloped him, and from those grids suspended from the roof had come the energy for a stupendous vital change. When the fluid had receded he was still an Earthman in form — but the chemistry of his body, of his very life itself, had been altered, conforming to the vital chemistry of Jupiter!
> > No wonder the frost of congealed water was almost hot to his touch now! No wonder he felt comfortably warm in the vast cold that must pervade this compartment! At temperatures and pressures normal on Earth, he knew that he would evaporate swiftly into gas!
> > And now Gregory Cross made a new discovery — one that in all the excitement had escaped him before. He could hold his breath indefinitely. In fact, there was no involuntary impulse to breathe at all. He still possessed his lungs, but they no longer had any purpose except to enable him to make vocal sounds. His Jovian flesh needed hydrogen, not oxygen. Its energy came from a different sort of combustion. Perhaps that needed hydrogen diffused directly through his skin, his strangely altered flesh directly absorbing the swiftly diffusing hydrogen molecules. A feeling of untiring strength suffused him.

> > III.

> > NO TIME was given Cross for further speculation. Out of his daze he heard the distant buzz of the monster, spelling a code message: "Come! Jupiter moon."
> > A section of the globular compartment's wall folded outward. Greg tried to stand erect to meet the scrambling host of Jovians that found entrance through the opening. The demons clutched at him and pulled him roughly, whether in malice or haste he could not know. No weird nerve compulsion was used now, only the power of brute numbers. The leader of the band, who had communicated with Greg, was near, recognizable by the fact that he was larger than his fellows, and was marked with peculiar reddish dots over his eyes.
> > Half dragged, half carried by dozens of thin, encircling arms, Gregory Cross presently found himself outside the transformation compartment. He was being borne along a cylindrical tunnel whose walls were transparent and frostless. Beyond them was Jupiter.
> > Confronted thus by the vivid reality of the giant planet's eternal, raging holocaust, Greg almost forgot his present position. He could see little through that blinding maelstrom, it was true; but from that little, one could still construct a mental picture that was more complete.
> > Wind. Lightning. Rain. Rain of liquefied ammonia, it must be. Greg could not smell its acrid pungence; but this, he decided, was natural. The sensitivity of his olfactory nerves had been changed, along with his flesh. On Earth, the water vapor in the air is almost odorless, too, as a result of human conditioning to its constant presence.
> > The rain thumped against the clear roof of the tunnel with the maddening roar of an avalanche. It was reddish, mucky rain, filled, no doubt, with the powdered ejecta of volcanoes. Not hot volcanoes such as existed on Earth, for Jupiter must be cold almost to the core. This vast world was composed largely of gases. The great cloud from which it had been formed, torn from the Sun by the passage of another star, had contracted slowly because of its low density.
> > Cold, however, does not deny the possibility of violent physical and chemical changes. On Jupiter there was still heat enough to produce tremendous explosive forces. Differences of high pressure in the vast atmosphere still could create winds that hurtled along at speeds of hundreds, even thousands of miles an hour. And deep in this planet's solid core there was still warmth enough to change liquid ammonia to gas, creating pressure that could move masses of rock huger than the Earth. Thus Jupiter must still have belching volcanoes, erupting not molten lava and steam, but cold, speeding vapors, and the muck of silicious dust.

> > ***

> > OUT THERE beyond the curving, transparent walls of the tunnel, Gregory Cross thought that he could occasionally glimpse hills and rugged, rusty crags through the blur of the eternal storm. There was no illumination out there save that provided by the blinding flares of lightning. Through the thousands of miles of atmosphere above, no trace of the distant Sun's rays could ever penetrate.
> > The realization of being buried down here, beneath all those countless tons of ammonia and methane, created not as they were on Earth, as the result of the decay of organic material, but by the simpler processes incident to titanic pressure, brought Gregory Cross a fresh wave of panic that was half nostalgia.
> > In the wild blur of the storm he glimpsed flying, tattery shreds, and wondered whether they were just refuse borne on by the hurricane, or living things, adjusted to this hell, like the Jovians themselves.
> > Like a bit of flotsam, he was carried on by the hurrying, buzzing multitude of gray-white horrors. Sometimes his feet touched the floor, and he managed to walk for a few steps. Rough, horny bodies scraped against him. Occasionally, during the long minutes of passage through the tunnel, he thought of escape. But he knew that such an idea was useless, for there was nowhere that he might go. There was nothing now for him to do but let things happen.
> > The passage debouched at last into a chamber, whose colossal expanse must have been many miles in extent. Partly, at least, it must have been imbedded in the ground. Its roof was a maze of gigantic girders, that seemed capable of combating even the gravity of Jupiter for all time. Far off in the distant, murky shadows, Greg saw dull glimmers that looked like flames of intense heat, shielded to protect Jove's cold-born folk from the killing warmth. Yes, they needed heat to fabricate metal. And they knew how to create it. For everywhere on this ghastly world, in spite of the low temperature, power surged madly, waiting only to be harnessed.
> > The floor of the chamber was dotted with machines of various kinds, moveless now amid a host of Jovians, who seemed to wait patiently for orders.
> > Wonderingly, Greg Cross looked at the three immense, disc-shaped things of metal that rested in a broad, sunken area. Their height was only a few hundred feet, but their diameters were easily a mile or more.
> > Into each, through narrow entrances, Jovians were swarming in a steady stream. Mingled with them were occasional articulated contrivances — robots.
> > Greg, his mind blurred and bewildered, allowed himself to be jostled on, until he, too, was aboard one of the gigantic vehicles. Up inclines, and along passages alight with a soft phosphorescent glow he was carried, until he found himself in a spheroidal chamber of about the same dimensions as the one in which he had first awakened. Its sides were of metal, and it had no windows. But at its center was a crystal globe, and near the globe were metal cords, supported in a divided arrangement by a hooplike contrivance. Each cord. disappeared into a hole in the curved wall.

> > ***

> > NO ATTEMPT was made to fasten the Earthman. But neither did he attempt to misuse his freedom. Temporarily a lethargic spell, perhaps related to the compulsion which had once gripped his nerves, had melted his will. He slumped down wearily beside the crystal globe.
> > All but one of the Jovians had departed. This individual was a leader, marked with red dots over its eyes. That it was the same leader that Greg had first seen, there was little doubt, for always, since he had been hustled from the transformation compartment, the creature had kept close to him.
> > This individual squatted before the crystal globe. Sucker-tipped fingers pulled a cord. Suddenly, within the globe, there was light — a picture of the chamber in which the three colossal discs rested. The place was deserted now; the horde of Jovians that had been gathered in it doubtless were all within the discs.
> > Another cord was pulled, and the picture in the globe seemed to sink downward. The great craft was rising. Now it pressed against the roof of the chamber. There was a soft vibration of crescendoing energy, then a tearing, pinging noise, as the vessel tore through the mighty girders of the roof, as easily as a punch press might drive a hole through cardboard. For a long time after that nothing was visible in the vision globe but a dark fog flared with lightning. Greg knew that the craft was shooting up through the atmosphere of Jupiter.
> > The vision globe cleared at last. Mirrored in it were the stars of space, the scattered forms of Jupiter's satellites, and a vast sea of boiling clouds — Jupiter itself at close quarters. Some of those clouds were white and clean. Others were tinted with red or gray or blue, doubtless by the presence of volcanic dust of those various shades.
> > Everywhere was a frozen, awesome silence. Now the two other ships emerged from the clouds and glinted in the Sun. Jupiter's bulk receded. One of the moons loomed ahead. It was Ganymede, largest of them all, almost as big as Mars and marked in a similar manner.
> > There was only a gentle, soundless vibration. Greg could almost feel, in that soft throb, the battle of the mechanical colossus that bore him, with the mighty gravity of Jupiter.
> > What was going to happen? Greg felt a new interest in the things around him.
> > "To moon?" he questioned in whistled code.
> > "To moon," came the Jovian's buzzing answer.
> > Gregory Cross would have made other inquiries, had he known how it might be done.

> > IV.

> > IT WAS hours later that the ships settled toward the deserts of Ganymede. The Earthman looked at the tumbled, dusty dunes, sad and lifeless. Somewhere here, he supposed, he would die. Just how or when this would happen, he, of course, did not know. Yet his interest in the fascinating mysteries that were unfolding before him remained at high pitch.
> > What was that in the gorge which now lay below? A city? Slender, ruined towers of white stone. Odd, polygonal courtyards and plazas, with blue shadows stretching across them! It was a city — but one which bore the stamp of ancientness and utter desertion.
> > Presently, guided by its control cords, the disc landed at the lip of the gorge, close to the metropolis.
> > Only for a minute was there delay before other developments came. From several exits in the ship's flanks swarms of Jovians were pouring. But there was something queer about them! At first Greg thought it might be only a trick of the bright sunshine, or some optical aberration of the vision globe. Then he decided that neither of these guesses was correct. The flesh of these creatures, scrambling madly and jubilantly from the vessel, really no longer was gray-white in shade! It was pinkish instead, almost like human flesh! Something had happened to those Jovians — something radical and strange and bizarre — else how could they venture forth unprotected, here where there was considerable solar warmth, and where the pressure was so low?
> > Gregory Cross gave a hoarse cry of surprise.
> > Of its own volition the leader beside him began to buzz a message: "Jovians as Terrestrians," it spelled.
> > It was not difficult now for Greg to guess what was meant. The life-chemistry of these creatures from Jupiter had been changed, so that it now corresponded with that of Earthmen! These beings had submitted themselves to a process which was the reverse of that to which Greg had been put.
> > Their motives in bringing him across space, from Earth, seemed clear now in part at least. They had wished to study his flesh, that they might know every phase of the life-principle that animated it. For they had wanted to migrate to Ganymede, in whose warmer and far thinner air living things suited to Jovian conditions could not survive for a minute without artificial protection. Greg realized that it was from his body that they had learned how to change themselves. For long months he must have been on Jupiter, lying inert in a state of suspended animation, while they made their intricate tests. During that time, perhaps, they had built the disc ships, fitting each with the apparatus necessary for the transformation, as soon as they had learned enough to build such apparatus.
> > Yes, part of the purpose of his bizarre interplanetary adventure was plain now to Gregory Cross. But how did this ruined city here on Ganymede fit into the picture? Who, in some bygone age, had masoned the stones of its towers and walls?

> > ***

> > GREG whistled out a code message. "Jovians as Terrestrians. Yes," he spelled. "Moon — Ganymede. Jovians — Jupiter. Ganymede — Ganymedeans. Ganymedeans. Ganymedeans. Ganymedeans."
> > While he whistled the dots and dashes, Greg pointed to the metropolis pictured in the periscopic view revealed by the vision globe.
> > The suckerlike grasping organs of the hideous leader trembled as with intensity of desire to probe out the meaning which this Earth creature was trying to convey.
> > "Ganymedeans — yes," it buzzed at last. "Terrestrians — Earth. Jovians — Jupiter. Ganymedeans — Ganymede." And then: "Jovians — Ganymedeans!"
> > The leader's rasping voice seemed loud with excitement, as it made this simple statement, identifying the peoples of two worlds as the same.
> > But the leader did not end its message here, but continued to spell words into which, by what must have been a momentary touch of genius, it managed to inject real, discoverable meaning: "Ganymedeans as Ganymedeans — years — years — years — Sun hot. Good — yes! Years — years — years — Sun cold. Good — no! Ganymedeans — Sun hot! Ganymede cold. Jupiter — cold — cold — cold. Ganymedeans — cold — cold — cold — no! Ganymedeans as Jovians. Jovians cold — cold — cold — yes! Ganymedeans as Jovians — cold — cold — cold — yes! Ganymedeans as Jovians to Jupiter — years — years — years. Good — yes. Good — no! Large gravity. Large storm. Ganymedeans as Ganymedeans — many. Ganymedeans as Jovians — many — no! Sun cold — Sun hot! Ganymedeans to Ganymede — no! Science — no! Terrestrian to Jupiter — science — yes! Ganymedeans as Ganymedeans to Ganymede — yes!"
> > Quaint, intricate phrases full of obscure significance. Yet Gregory Cross, trained to the probing of secrets, understood. Ganymede was the original home of the Jovians! That had been in incalculable ages past, when the Sun had blazed in its hot prime. But it had lost its head, and Ganymede had become too cold for its people. Then, doubtless by studying Jovian life, they had learned to change themselves. Transformed, they had lived precariously on Jupiter for ages, their numbers slowly dwindling. When the Sun had warmed again, heated by the influx of the meteoric matter from space, they had wanted to return to their home world. But somewhere, during their long Jovian tribulation, they had lost the science which would have enabled them to change their life-principle back to its native form. Greg knew that the study of his flesh had turned the trick. The native life of Ganymede and the native life of Earth clearly belonged to the same order — breathing oxygen, needing water, instead of liquid ammonia, to flow in its tissues.
> > "Lord!" Cross gasped. "I see it all now!"
> > An odd wave of elation came over him, born of the knowledge that he had been the pivot of a great achievement. He thought of Earth and its people, suffering under the rays of a swollen Sun, and for a moment his elation gave him fresh hope. "Terrestrian help Jovians," he spelled. And then, insistently: "Jovians help Terrestrians!"

> > ***

> > THERE WAS a long pause, while the triple, frosty orbs of the leader studied him carefully. Did this devil understand what the needs of the Terrestrians were? Probably. Yet, even with its vast learning, would it know how to fill those needs? Conquering withering waves of heat streaming down upon an entire planet much nearer to the Sun than Ganymede, was too fast a problem. Did this alien horror feel any gratitude toward him? And if it did, was that gratitude great enough to prompt it to attempt a fulfillment of the gigantic favor he had asked?
> > Greg felt his hope melting in a sea of doubt.
> > Then the leader spelled his rasping reply. "Jovians help Terrestrians — no — yes — no — yes — no — yes."
> > Gregory Cross wasn't sure that he understood this communication, but he took it to mean that the leader was expressing uncertainty of some kind — doubt, perhaps, of his and his people's ability to be of assistance to the Terrestrians.
> > Anyway, here in this strange, spherical control compartment, with fantastic magic all around, and with a living intelligence cast in fearful form scrutinizing him with unfathomable frosty eyes, it was easy for a man to believe in — nothing at all! Gratitude? Greg was sure now that he had been foolish even to think of gratitude, on the part of this Jovian, even as a possibility. It is biological law that life in its various forms is largely inimical and competitive. One kind of life may use another kind to suit its purposes, but sympathy between the two is an exception rather than the rule.
> > Greg thought for a moment that he was going to crack — that he was going to scream insanely with the torturing anguish of utter homesick loneliness. Then he realized his self-imposed responsibility. Earth. Mankind facing extinction. Earth — Ganymede. Earth had had a moon of the same character as Jupiter's many moons. That moon might serve a purpose!
> > Thus, in an entirely unexpected flash, Gregory Cross conceived an idea. He was on his own, wasn't he? Yes, it was best for a man to be on his own. At least he could trust himself. Here was a great ship, powered with energy inconceivable. There were its controls. Greg had watched the Jovian leader work those controls. It had seemed very simple.
> > But as yet he had no thought of attempting to put his idea into practice. It seemed too wild, and too full of uncertainties. Or perhaps he was still under the spell of some mild form of neuronic compulsion, originating in some way from the mind of the Jovian leader. The latter's body was adorned with a few, odd, metallic devices which Greg hadn't noticed before. Maybe in one of those devices there was an apparatus that served to transmit the compulsion to his nerves—
> > Now the leader clutched Greg's arm with a cold tactile appendage. Puzzled, the Earthman allowed himself to be led from the control compartment. The latter's transparent door closed behind them. Now they were moving down a phosphorescent passage. There were no longer many Jovians about. Most of them had been transformed, and had left the ship.

> > V.

> > PRESENTLY Greg and his weird escort reached the transparent valve of a great spherical compartment. It was not difficult to guess the nature of this compartment, for, except for its gigantic size, it was identical to the globular chamber where Greg's Jovian awakening had occurred. Within it were the same kind of grids, and the same fluid wetness. It was a place of transformation.
> > "Jovian as Ganymedean," the leader buzzed. "Terrestrian as Terrestrian."
> > Gregory Cross looked at his frosty, gray-white hands, and longed with all his might to be "Terrestrian as Terrestrian" once more, instead of the strange outcast he was. But if he were transformed now, his last chance of acting on the idea he had thought of would be gone. In the hideous cold of super-chilled methane gas which pervaded the control room of this ship, he knew that no oxygen-breathing creature with water as its vital fluid could survive for more than a few seconds. Greg knew that he'd have to stay as he was, or discard his scheme.
> > He acted on impulse, for there was no time for further thought. The Jovian leader was busy now with the lock of the transformation compartment. If it had existed at all, the compulsion was momentarily in abeyance now. Under other circumstances the seeming carelessness of his weird guard might have struck Greg as being odd. But in this instant of beckoning action his mind had room for only a few essential ideas.
> > He wheeled about lithely, and darted into a dark, narrow tunnel. The feeble gravity of Ganymede lent wings to his feet as he bounded along through blurry gloom. The tunnel proved to be part of a veritable maze. It had many branches leading to hundreds of various supply compartments. Exerting an effort to keep his bearings, Greg followed one of these branches, and continued on, deep into the dark, silent labyrinth. At last he climbed up into an inky cavity, packed with cylinders of light-weight metal, filled, apparently, with some semiliquid substance, for they gurgled faintly when he scrambled over them.
> > "Stupid," he muttered, addressing himself. "Stupid fool! They'll find you sure!"
> > But minutes passed, piling up into hours, and still there were no signs of pursuit. Nor was it difficult to guess why. This mile-wide ship was so huge that to search all of it was no mean task. And even then places like his present refuge would be easy to overlook.
> > Now and then Greg could hear distant sounds which told him that there was still activity on the vessel. At last weariness overtook him, and he slept. He awoke to feel the grip of a neurotic compulsion clutching at his body, commanding him to climb out of his hiding place. But he gritted his teeth and resisted. Presently there were sounds of movement in near-by chambers, and the slithering scrape of something moving away from him. The compulsion waned and vanished.

> > ***

> > AFTER A TIME the tension of fear left him, and he slept again. On awakening, he felt hungry. What sort of food did his strange, alien flesh require? He didn't know. Nevertheless, exploration and a bit of experiment might give him the answer. The first things that came to hand for investigation were the stacked cylinders under him. He took one and battered it against the wall. A clear syrupy substance oozed out, and he touched a droplet of it to his lips. It had an acid taste which did not displease him. He tried a little more of the stuff, and then waited. There were no bad effects, so he consumed half a cylinder of the mysterious chemical.
> > The silence was heavy, eloquent of desertion. Refreshed and curious, Greg decided to look around a little. In a room not far away he found a large, square window. Beyond it the Ganymedean city sprawled, beautiful and fantastic under the rays of a rising Sun. Once more its plazas and courtyards were teeming with activity, after the passage of ages. Across the gorge that sheltered it, a tremendous column of steamy vapor was rising from a spot of incandescence on the dry sand. Around that spot, many of the creatures who had made the exodus from Jupiter were gathered. Pointing toward the area of fire were scores of massive, sharp-pointed electrodes, arranged in a circle.
> > What was the meaning of this activity? Greg could only guess. The rising vapor looked like real steam. Perhaps transmutation of elements was taking place there in that furiously active pool of atomic incandescence — transmutation by which the atoms of sand were being torn apart and built up again to form molecules of water vapor and oxygen, to conquer the dryness of Ganymede, and to replenish its depleted atmosphere.
> > Greg wondered vaguely why these weird folk hadn't long ago found a way to study the life of Earth, change themselves to suit Ganymedean conditions, and return from Jupiter to their native world. They had evidently possessed some knowledge of space travel for ages. But then he saw that there might be many reasons why they had failed to do this. Going to Jupiter from Ganymede, considering the relative gravities of these two worlds, is a comparatively simple task. Going to Ganymede from Jupiter is a far different story. It takes a mighty and well-directed force indeed to fight successfully the all-mastering attraction of the Titan of worlds. Perhaps, during those earlier days of Ganymede's glory, her people had been able to reach Jupiter and return, on a small, and doubtless very dangerous, scale. But it was easily possible that only recently the Jovian colonists had gained sufficient mastery of atomic power to send a spacecraft to Earth and to escape from the world their ancestors had chosen.
> > Gregory Cross could waste no more minutes in impractical speculations. If he was going to act, he must do so now, while he had a chance.

> > ***

> > HE SEARCHED supply rooms until he found a heavy metal bar. Then, with the tingles of fear rippling over his body, he proceeded to retrace his way through the maze of passages.
> > Without incident he reached the place before the entrance of the transformation compartment where he had escaped from the custody of the Jovian leader. Or perhaps he should think of the creature as a Ganymedean leader now.
> > Cautiously, Greg proceeded on toward the vessel's spherical control room. It was well that he was careful, for before the door of that room a robot crouched, on guard. Greg's heart was in his throat, but taking advantage of an angle in the wall, he continued his cautious advance.
> > And then, like an avalanche of fury, he leaped upon the unsuspecting mechanism. The massive bar he carried arced in a diaphanous blur. There was a sharp, thudding crash of crumpling metal, in the cold, compressed atmosphere of methane. The bar rose again, smashed down, not once, but a score of times. Little splinters of crystal skittered across the floor, glinting jewellike in the phosphorescent illumination.
> > Now the assassin of this soulless mechanical thing darted back the way he had come. He found a ponderous, sliding door, niched in the wall, its purpose evidently being to seal the passage. Perhaps a safeguard against possible mishaps in space. It took a minute for Greg to locate the levers that worked the huge valve, but he did so at last. There were two sets of levers, so that the portal might be moved from either side. Greg smashed the set on the side away from the control room thoroughly with his bar. Then, under his manipulation of the other set, the portal slid quietly into place across the tunnel.
> > In all the other tunnels near by, there were similar doors. Greg doctored their external levers, and closed them all. At least, his intended activities wouldn't be interfered with right away.
> > The transparent door of the control room was locked in some manner. How, Greg could not discover, so he attacked it with the bar. This barrier was not of metal as were the other doors, but of some glassy material almost as tough.
> > Even its much less massive construction did not yield until Greg had pounded and pried at it for an hour or more. Now he crept through the breach he had made. The vision globe in the control room was still active. In it the city could be seen, taking on an aspect of new life, the Sun gilding its fantastic spires and ramparts.
> > But Greg's gaze did not halt here. Instead, it wandered to cable controls of the ship, the ends of the cables supported around the rim of a hooplike frame. Which one of those cords had the Ganymedean leader pulled to cause the vessel to rise? The third in the upper right quadrant of the circular support? Greg wasn't quite sure, but there was only one way to discover.

> > VI.

> > THIS, then, was the moment for action to begin. Greg's hand reached out and clutched the looped end of the cable. There was a prayer in his heart as he tugged gently. In his mind there were tense, maddening memories of Earth — pictures of gray, sun blasted plains, of blackened ruins, and of bleached bones imbedded in the desiccated stuff that had once been rich humus soil. They were human bones, yet they never could be as pathetic and appealing as the few million people who still survived in underground retreats and vacuum-shielded habitations. Gregory Cross had a little cousin who was five or six now. He lived with his father in the ruins of Chicago. That is, he did if he hadn't starved, or perished in one of the fierce storms that came nightly.
> > The memory of the child's big, questioning, haunted eyes ached in Greg's thoughts as he waited for some sign of response to his tugging of the cable.
> > Suddenly the disc ship gave a soft, swaying lurch. The surface of Ganymede revealed in the vision globe was dropping swiftly beneath.
> > Gregory Cross accepted this fact without elation, for the shock of success had rendered him emotionally numb. Still, his reasoning powers seemed to have achieved a crystal clarity and coolness.
> > Because ignorant tampering might result in a crash while the ship was still so close to the Jovian moon, he waited until the mighty thing that had responded to his command had attained the freedom of space before he did anything further.
> > The craft was curving toward Jupiter, doubtless drawn in that direction by the gravity. Otherwise, it was moving at a little less than a right angle to the position of the Sun.
> > Both of these circumstances required prompt correcting. And so Gregory Cross began to pull cables, one after another, gently, pausing each time to note the effect of his act. Thus he discovered that for each cable there was a mate, which, when pulled, neutralized the former's effect. Thus there was a cable for starting the ship's propulsive mechanism, and for speeding up energy release by merely increasing the pull. And there was a corresponding cable to decrease energy development, or to shut it off entirely, drawing the first cable to "off" position. Steering of the ship was accomplished by four cables, set at equally spaced points on the circumference of the supporting hoop. If you wanted the ship to turn right, you tugged the cable on the right. If you wanted the ship to turn left, you pulled the opposed mate cable on the left. In a similar manner, the directions "up" and "down," taken in relation to the level on which the vision globe stood, were controlled by the opposed cables at the top and bottom of the hooplike frame.
> > Pleased with his discovery, Greg proceeded to direct the flight of the vessel toward the Sun. In the glare of the solar orb Earth could not be seen at all with the naked eye. But this did not matter — yet.

> > ***

> > HIS LUCK seemed remarkably good. Yet there was still plenty to worry about. He looked into the vision globe for signs of pursuit. But no angry bulks were rising from the dwindling form of Ganymede. He listened, and he thought he heard distant, grating noises. Doubtless there still were Jovians — Ganymedeans now — somewhere on the vessel. Would they try to get to him? Greg didn't know. If their bodies had been transformed from a liquid ammonia basis to a water basis, they couldn't live here in this part of the ship. Then, too, there were those mighty doors that could not be opened in a normal manner by anyone beyond them.
> > Greg was startled and scared when he saw a small torpedo-shaped craft pictured in the vision globe. It was near the great disc ship he was guiding. At first he couldn't imagine how it had come so close without being noticed, and then he guessed the truth. It had been launched from the great disc itself! Aboard it doubtless were Ganymedeans who had been in the ship when it had started its runaway flight. Would they attempt some offensive move? No, they were hurtling swiftly away — returning to Ganymede. Doubtless they thought it futile to try to halt the colossal disc with their puny craft. To them, the former was now only a vast, onrushing mass of metal, derelict and dangerous.
> > "Better and better," Greg muttered to himself.
> > Yet still there was a deep conviction in his mind that his good fortune could not last. There were so many factors, in the great riddle with which he was involved, that he knew nothing about. And he was depending so much on luck and guesswork.
> > He was aware, too, that if the wild scheme that he had in mind for bettering conditions on Earth were carried out, he would surely perish. For one thing, from the viewpoint of the alien vitality which now animated his body, Earth was, and had always, been, a place of death.
> > Yet he pulled the throttle cable to full. The ship was accelerating at an enormous rate, he knew. How fast would it go at the highest velocity it would attain? He knew of no way to answer this question now. He could only guess and hope.
> > The disc was better than a mile across. The Moon — Earth's satellite — was 2,160 miles in diameter. A great difference! Still — speed could do a lot to make up for lack of size. Then, too, the vessel evidently had enormous stores of power locked in it somewhere. What if that power were released suddenly, all at once? Of course he could not be sure that such a release of energy would take place — but he could be optimistic, knowing that he was doing his best.
> > He ceased to wonder and to question for the time being, and devoted his attention to mathematical calculations which he scratched on the metal wall of the control room with the diamond set in the black onyx of his signet ring. That ring had come through all his bizarre adventures, unchanged and unscathed, except for a slight tarnish.
> > Meanwhile, the disc ship tore on and on, the dwindling Jovian system behind giving evidence of its already vast velocity. It was moving almost at right angles to the plane of its flattened shape now, with what was intended to be its top facing the direction of its Sunward flight, so its acceleration provided a substitute for gravity, what acted from a natural, "downward" position.

> > ***

> > FINISHING his tentative computations, Gregory Cross proceeded to examine the vision globe more closely. Encircling it in various directions were rows of fine, graduated marks, like the graduated marks on the edge of a meter stick or ruler. Greg guessed that these minute lines were for the purpose of directing the ship's course more accurately, and for taking trigonometric measurements of its position with relation to other bodies in space. Some of these marks were longer than others, and one was longer than any, being tipped with a little triangle, like an arrow point. Greg soon discovered that when he looked through the clear, crystalline substance at the center of the triangle, he was looking directly along the line of the ship's course. Beyond, pictured in the globe itself, was the blazing blob of the Sun, and the surrounding blackness of space. The triangle, then, might be used as a sort of sight.
> > Greg squinted into it and pulled control cables, adjusting the disc's course more accurately toward a spot to the right of the solar orb, where he could now see the dim, hazy speck which marked the position of Earth and its satellite. Though his knowledge of the time-factors involved had been largely conjecture, his calculations had at least enabled him to predict crudely the position of Earth in its orbit, enabling him to locate it with a fair degree of accuracy.
> > As Greg had noticed vaguely before, the vision globe was periscopic; that is, it provided a means to look in all directions, depending on the angle from which you peered into it. If from the right, you saw what was on the left of the ship; if from the left" you saw what was on the right. Straight ahead was viewed from its rearward side, and so on. But Greg was not interested in this trifling phenomenon now.
> > WEARY, and concluding at last that his search for evidence of danger was useless, he procured a cylinder of liquid food preparation from his former hiding place, and returned to the control chamber. Having eaten, he went to sleep.
> > On awakening, hours later, he found the view in the vision globe changed considerably. The Sun was huge now; Earth was a bright star, and the Moon was a lesser star beside it. At speeds of a thousand or more miles per second, even interplanetary distances are swiftly shortened.
> > Greg made other calculations, taking into account the movements of the Earth and the Moon. Once more he adjusted the control cables of the ship.
> > "It won't be long," he muttered. "When this ship reaches the vicinity of Earth, it will be doing about ten thousand a second. That's thirty-six million miles an hour! I hope what you're trying to do doesn't just make you a fool, Greg Cross. I hope you really succeed in helping those poor devils back home. Otherwise your fade-out will be — plain suicide."

> > VII.

> > HE didn't notice the stealthy approach of the robot-shape that had dropped from the open end of something that was like a ventilation duct, set high in the wall of the passage. Behind him, the robot's beetlelike body reared up like a man, towering over him. Four metal arms encircling his torso with a grip that was literally one of steel.
> > Realization of what was happening maddened him. Through this semi-intelligent henchman of theirs, the Ganymedeans had at last found a way to reach him. Waves across space — commanding waves — and the mechanical brain of the robot was able to fill in the details of action. Doubtless the Ganymedeans might have mastered Cross directly, by means of their neuronic compulsion, acting through receivers which must exist on the ship. But this way was simpler. Perhaps they had waited until now, only to play cat and mouse with him.
> > Gregory Cross fought the robot with an insane fury that was backed up by all the horror a human being could feel for these demons that had come out of the cold holocaust of Jupiter, by the inhuman strength of his altered body, and by all the anger that a defeated and vital purpose could give him.
> > He achieved nothing. The stolid, unchanging grip of the automaton did not relax. Greg's exertions only served to deplete his energies, and to bring him utter exhaustion. He felt himself carried along by his metal conqueror. Dazed to the point of unconsciousness, he thought he heard watery sounds around him. His mind blurred away slowly—
> > The next he knew, the robot was carrying him swiftly along the same corridor, but toward the control room instead of away from it. He couldn't guess what had taken place during the considerable time that he must have been inert. But there was something odd about the various details of the situation in which he found himself. The sounds made by the robot's feet on the metal floor of the passage seemed less loud than they had before, as though they were transmitted by a medium of lower density. The illuminating phosphorescence had a different quality, and Greg felt cold.
> > But sight of the control room entrance ended his vague speculations. Fixed purpose took possession of him. He struggled with a new weakness in the robot's clutches. The intensity of his single objective allowed him to feel no wonder when the mechanism released him. He scrambled to the battered door, and through the opening that had been blasted in it.
> > In the control room, on hands and knees, he peered into the vision globe. Now he pulled control cables, sighting through the center of the triangular mark. The ship was perfectly aligned at last on the little yellow arc that was the Moon, ahead. The Earth, beside it, was a small, foggy crescent.
> > Greg stepped back. He was aware that only minutes remained before the crash. His job was finished. Unless the robot interfered—
> > He turned defensively toward the thing, his body at a crouch. But a slender metal arm shot toward him like an adder's tongue, wrapping itself around his middle. He was yanked from his feet and dragged through the ragged rent in the control room door.
> > "Damn you!" he screamed as the robot bore him off, down the corridor.

> > ***

> > THEN, slowly, understanding began to dawn on him. He saw his arms, his hands. They didn't look frosty and ghoulish any more — they were the shade of normal, bronzed, Earthly flesh! He'd been retransformed! The robot must have carried him to the transformation chamber while he was unconscious, and had put him through the reverse of the process to which he had been subjected on Jupiter! The air around him wasn't compressed methane now, but was evidently of much the same composition and density as that of Earth, for he was breathing it in a natural manner! The methane must have been pumped out of these passages and chambers, and replaced by comparatively warm oxygen and nitrogen from supply tanks! The robot had been the agent of this change, of course. Yet back of the robot's acts certainly there lay the purposes of keener, kinder minds than its mechanical brain might possess. Greg knew then that those minds were certainly Ganymedean, sending their orders across the void doubtless by means of the artificial cosmic rays which the queer folk of the Jovian system used for long-distance communication—
> > "How — how can, it be?" he muttered. "It's not — sense! Those devils never would—" He left the phrase unfinished, for it did not keep pace with his speeding thoughts. "Unless," he finished savagely, "they've got some new dirty trick up their sleeves!"
> > But this was no time to think. Too much was happening. The automaton was now bearing Greg down a side tunnel. The tunnel ended in a cylindrical compartment which housed a small, tapered space boat. Greg soon found himself inside the craft with his metal escort. There was a thrusting jolt as the little vehicle was hurled from the now opened end of the cylindrical compartment by a launching device, and projected out into empty space beyond the outer shell of the great discship.
> > Then came the dazing pressure of terrific deceleration, as the robot plied control cables to reduce the speed imparted to the small vessel by its mother craft.
> > Again Gregory Cross' brain was dipped in the blackness of oblivion. When he came out of it, the great disc, directly visible through an observation window at the front of the cabin, instead of through the medium of a vision globe, had dwindled to a gleaming metallic dot, far ahead. Directly in its path was the crescent Moon.
> > Such was the picture which his eyes captured in an infinitesimal instant. But movement in that picture was far too swift for human eyes to follow.
> > In a split second the collision of Moon and disc ship occurred. There was no sound to it in the vacuum of the void — just a sensation of a stupendous puff of light that brought aching blindness. That light was a by-product of a speed of ten thousand miles per second converted suddenly into the energy of heat, and combining with the greater heat and terrific blasting power of the atomic fuel in the disc's tanks. The fuel that had been set off by the inconceivable impact to which it had been subjected.
> > WHEN Greg's vision had cleared again, he saw, where the Moon had been, only a vast pall of dust and rock fragments, shining faintly red with heat. Slowly, along what had been the disc ship's line of flight, it was lengthening out, while it expanded laterally. Its farther end, pulled by Terrestrial gravitation, was curving around the Earth, whose foggy bulk hung unobtrusively to the right. Across its deserts, visible here and there through the fog, a friendly shadow was appearing — a shadow cast by the lunar wreckage.
> > Greg knew that that cloud of rock and dust which had once been the Moon would gradually disperse itself around the Earth, forming at last a screen of debris that would shield Terra from that awful torrent of solar heat and light, dimming it to a point where it would no longer be dangerous or harmful. This meant new comfort once more, new surface cities, new vegetation. New life and freedom to the peoples of Earth! And because one moon had broken up to form myriads.
> > Gregory Cross could hardly believe what had taken place. He turned toward the robot beside him, and watched the thing dumbly. It was manipulating control cables. The space boat was veering away from the lunar pall to escape being riddled by passing through it. Once again, to a lesser degree than before, came that fierce pressure of deceleration. But in spite of decreasing velocity, Earth swept swiftly past, and began to dwindle astern.
> > Greg felt a flash of panic. What was the robot trying to do? But then Greg was reassured. The automaton was only doing what it must; it would take hours to bring the spaceship to a halt, for, before its launching, it, had been aboard the great disc ship, and had naturally received the same tremendous acceleration. Not until the little craft had lost its terrific speed, could it begin to retrace its way.
> > But still Gregory Cross was bewildered. "The Ganymedeans are friends," he said dazedly. "They must be friends because they — did all they did. Even when I ran away with their ship. But how can such demons be friendly to Earthmen? Different kinds of life generally aren't—"
> > Then Greg, found what must have been the answer. "Let's reverse the situation," he muttered to himself, trying to straighten matters out. "Supposing some creature from another planet were brought to Earth. Supposing it benefited mankind as much as I — unwittingly — benefited the Ganymedeans. Wouldn't there be at least a good chance that Terrestrians would be kindly disposed toward that creature and all its kind, even if the price was a costly spaceship?
> > "The, Ganymedeans must have guessed what I was going to do — about the Moon. Nothing difficult there — just parallel reasoning, that's all. Maybe sometime they'll come to Earth — the heat won't stop them, now that they're changed. Maybe they'll come to conquer, but not for a long time anyway, for there are only a few of them, and they have plenty of room on Ganymede. And between now and then, lots of things can happen. Terrestrians are clever, too."
> > Many hours later, having checked its speed, and having looped back in space, the little ship landed on Earth, close to Greg's laboratory. The robot that had guided it went inert, perhaps having served its purpose for all time.
> > But from a box attached to the wall of the cabin came tinkling sounds spelling out dots and dashes, that had their origin far across the interplanetary wastes.
> > "Terrestrian help Jovians as Ganymedeans," they spelled naively. "Ganymedeans help Terrestrians."

> > THE END