Rebellion BAB-73-R32 looked up slowly from the report he had been reading. His keen gray eyes narrowed slowly in thought. "So that was the reason for the discontinuance of the type R-SI. An excess of initiative on the part of Hol-57." Bar-73-R32 considered the thing carefully. "Exactly the same type scheme I had in mind-nearly fifty years ago-before my type was started." For nearly an hour Bar sat still, looking unseeingly at the silver-gray metal wall of his laboratory office, or staring sightlessly at the towering Eugenists Bureau, the Tharoo control offices across the garden court. And at the end of that hour, Bar invented a thing as wonderful as any idea any human ever conceived; he thought of something utterly foreign to the humans the Tharoo masters had bred and selected for nearly one hundred generations. Bar-73-B.32 invented-secrecy. Three thousand years before, the Tharoo had landed on Earth, to find only a semisavage race of humans, indolent, peace-loving, all their wants supplied effortlessly by the growing things about them, a race decadent since the Machine had left Earth a paradise, free of danger, free of disease, three and a half millennia before their coming. The Tharoo Eugenists had seen before them a great problem, the rebuilding of a once-great race to intelligence once again. With high ideals, the first generation of Tharoo sought to aid mankind back to intelligence by intelligent control of matings. With deep interest in the problem, the second generation of Tharoo carried it on. The tenth generation of Tharoo-the twentieth of men-brought a world vastly different than the Landing Colonists had intended. Inevitably the Tharoo had bred a type of humans useful to them. The Tharoo did not desire any higher intelligence in men. They were very useful as it was. They had, with scientific accuracy, bred out rebellion, thoughts of secrecy, plotting, disobedience. Still, they had required certain human investigators and research students, because it saved them work, and because they needed them and these tasks required a degree of intelligence, a degree of initiative- Bar-73 was *ne greatest inventor the human race had produced in twice three thousand years. He was Maun Superintendent of Eugenics, the human director, under the Tharoo Head, of the great homes where humans had been bred with scientific accuracy for three thousand years, far beyond human memory, because even Tharoo records ran no farther back, and initiative had not been a desirable characteristic of Mauns, beyond any different conception possible to the humans of that time. The idea startled Bar-73. Only the complete soundness of nerve bred into man for three thousand years permitted him to maintain his calm unaltered. Immediately the consequences appeared to him, and immediately he realized a second thing would be needed. Not merely secrecy-but untruthl Invention. Every word must be an invention. Every act would be a lie, a thing unheard of by humans. But that, he suddenly realized, would aid him. The Tharoo would not doubt him. Bar was the absolute head of the Eugenics Buildings, in effect. His orders were obeyed, unquestioned; his reports alone reached the Tharoo Head. No discrepancy would be discovered. To a human of an earlier day the thing was inconceivably simple. To Bar -every word, every gesture, every thought must be labored, considered. And-it must go on for years! He paled at the thought. Slowly he rose and went to the great genealogical charts, where each type and characteristic of every line of the human race was shown. "Hol-57 saw it-fifty years ago. But four inventions of any importance have been produced this year. The Tharoo work less on science," he muttered softly. Already man had outstripped his Tharoo master. Bar-73 had made two great inventions that day. "Type R-i and type 8-14- crossed they should produce a research type-a scientist-with the initiative, the ambition and greater intelligence Hol-57 wanted and the Tharoo Head did not think was needed." Bar paused in astonishment. "If the thing works-as it must-a Maun type more intelligent than the Tharool" For an instant it hung in balance as Bar considered it. Then the subtle stiffness of determination came to him. Slowly he turned away from the charts and examined his card index, made some calculations, and at last wrote laboriously-two order blanks, then two more. Slowly, determinedly, he pushed an annunciator button. A musical hum outside awoke an echo of softly thudding feet. Gar-247-G-i2 came in. G-12 was a type bred for intelligent labor, for difficult manual labor, but yet work requiring intelligence of some degree. His eyes were deep-set and far apart, his head massive, well formed. And he stood seven feet six in height. He weighed close to three hundred and fifty pounds. Powerful as a Hercules, yet respectfully attending the six-foot Bar. "Gar, here are four orders, four mating orders. See that they are carried out." Gar saluted and took the orders. Slowly, Bar-73 sat down, his face somewhat pale. Elsewhere in the building a young girl, of the type known as R-i, surveyed in nervous doubt the slip Gar-247 gave her with a kindly smile. "It seems your mate has been found at last, Wan," he said gently. "May you be happy with him. Life is a long time, but there will be no more uncertainty. He will be yours, and you his." Gar-247 passed on to deliver the three other notes, his next call being a young man of the designation Jan-g4-S-i4. And then a girl, Tos-63-S-i4 and a man Bar-i2-R-i. These four slips had duplicates somewhere in the files of the Maun Superintendent, but somehow Bar-73 contrived to see that they were lost-for none watched to prevent that-and that certain others appeared, and none would question that, for what Maun would think of falsifying records? It was nearly a month before Bar called the couple Wan and Jan into his office and talked to them for several hours. They were two of the highest types the Tharoo had permitted, both keen minded, intelligent, understanding. They listened, and because they were young, scarcely twenty, they were ready to accept the words of the Maun Superintendent, to see perhaps a bit of the vast adventure. Never could they appreciate the full, titanic power of the thing they represented. Bar-73 did not see that. Still he. saw the possi- bility of giving to the Tharoo-the masters-the inventive type he felt was needed. The two left, were followed by the other couple, and they left, smiling, somewhat bewildered, but happy in each other. There was something evidently strange about their mating, but they really knew nothing of the records, nor the full processes, only that they were content and that they must do as Bar-73 had told them. Bar-73 contrived to be present when he was born. On the records, he was Rod-4-R-4. On Barb's records, he was Rod-4, without type designation. But on the bed he was very small, and very red, and quite noisy. Wan-i4 smiled up at Bar nervously, and Jan grinned down at Rod-4 broadly. "He's got a powerful-looking chest," said Jan, happily. As a matter of fact, what chest there was was almost hidden behind waving arms and legs, and a jaw let down for greater volume of sound. "He has," agreed Bar-73, nodding. "His head is broad-unusually broad." Shortly later, it was not so unusual. A child very like him was born to another couple, likewise officially one thing, and very secretly something quite different in type. Bar-73 hesitated before he made out four more orders like those first, for he had begun to realize more closely, more fully, that disaster meant not only death to himself, which he did not greatly mind, but a strange and terrible misery to eight innocent humans. For the first time Bar-73 saw there was more in his great work than mere shifting of-nature's forces. They were forces, greater forces than he ever would know, but he had met Jan and Bar-12 and Wan and Tos more intimately than he had ever before met the couples his little slips of paper brought together. But now he had seen that a second generation must follow. So he made out the other orders and conferred with four more young, happy, hopeful people. And watched as Rod-4 and Keet-3 grew. Later he began to teach them, and later there were four to teach. Bar-73 was an old man when he died, and at his recommendation, the Tharoo Head appointed Rod-4-R-4 his successor, an unusually keen-minded young man. How keen-minded, the Tharoo Head had no idea. Rod-4 started off with a tremendous advantage. Deception was not his invention, nor secrecy. He knew those already. And Bar-73 had done well in his choosing. Rod-4 was not merely far more intelli- gent than any human who had lived for the last six thousand years, He was infinitely more inventive. Bar-73 had been old when Rod-4 was a young man. By the time Rod began to form his own thoughts, Bar was very old, so Rod did not tell him all those new ideas of his. Bar had not been careful to avoid breeding rebellion back into the human strain. When that Tharoo Head vetoed Hold's plan fifty years before, he did not tell Hoi all his objections. There was rebellion in those strains, a thing neither Hoi nor Bar had been able to understand. Rod did. Rod invented rebellious thoughts, an invention as great as Bar's invention of secrecy. Bar had wished to produce an inventive type that the civilization he knew, the civilization of Tharoo masters and human slaves, might not cease to progress. Rod saw a far better use for inventive talents, and so, because he was a Eugenist as, of course, Bar had been, he realized his training confined him and his inventive ability. But-not too much. He could invent a great many sociological ideas. Rod-4 mated with Keet-3, and he saw to it that those others of his unique type mated among themselves, and he saw, too, that they were housed in a section of the city devoted to research students and technicians. He became very friendly with a group of physicists and atomic-engine technicians. The others of his group, finding their nearest neighbors were chemists, or electronic technicians, became friendly with them and, as children were born, Rod-4 suggested that they, being more than usually intelligent, learn a bit more than the work of their own parents-perhaps some of the learning of their neighbors-- Kahm-i stood six feet two in height, muscled with the smooth cords of a Hercules, his eyes the color of etched iron set deep and wide in his ruggedly molded head. His head looked large, even on his powerful frame. And there was a peculiar intensity in his gaze that annoyed many and troubled almost all. There were, perhaps, a dozen who enjoyed his company and noticed nothing in his gaze. But that may well have been because they too had a strange intensity of eye. Sahr-i, Pol-72, Bar-n and the others, so similar in build, carriage, body and coloring seemed almost brothers. And San-4, Reea-i and certain other girls were slim, lithe, deceptively strong; their clearly cut, almost classic faces were, perhaps, a bit overwide; their five feet ten made them perhaps a bit tall. But under the close-curled brown hair of each was the same type of intensely keen mind, in- tensely ambitious, the highest peak of intelligence the human race had ever reached in all its existence. Kahm-i had begun to realize his difference and-from his father, Rod-4-his mission, before he was ten. By that time he had proved himself so tremendously beyond any type of Maun which was supposed to exist that even the single-track, uninitiative minds of the neighboring technicians from whom he had gathered most of his knowledge began to wonder a bit, Kahm-as did those others of his strange type-became remarkable for his ordinariness only. He made an excellent listener, however, and as an atomic engineer cursed and wrangled over his machines, talking half to himself and half to the quiet, slit-eyed child, Kahm, who listened and watched-and remembered. He remembered not with the memory of a normal human, but with a mind that was photographic and phonographic. At a glance, he memorized every part and setting of instruments; every word he heard remained forever behind those strangely narrowed, strangely intent etched-iron eyes. At fifteen Kahm was apprenticed to an electronics technician, a strangely stupid apprentice, who must be told every detail, every movement, and the why of every gesture and connection. At fifteen San worked herself into a position in the records and documents department. She seemed to accomplish little. She was constantly turning over slowly, listlessly it seemed, the musty pages of the records, glancing casually over the close-typed sheets, and passing on. Sahr was apprenticed to an atomic engineer, a man who had become a close friend of his father. They made few friends outside their own group, this score of strange young Mauns. In the great city of rearing salt-white stone, gold, green, silvery metal and gem-hued glass, of sweeping parks, hundreds of thousands of Tharoo and millions of Mauns, they meant little. No one noticed or bothered with a score of young apprentice Mauns. A score among millions meant so little. One of them ruled the planet. A score of them turned the civilization that built those cities of stone and metal and glass upside down, and cast it out. "I am quoting," said San, smiling, "so don't blame me if the logic is faulty. "The Report on the Ancient Works, by Shar Nonlu. Year 137 of the Landing: "'From our most accurate estimates it now appears that not less than three thousand four hundred, and not more than three thousand seven hundred years passed between the fall of the ancient civilization of the planet Artd and the Landing of the Tharoo. "'For what period previous to this the Maun race had lived and developed their civilization it is nearly impossible to say with accuracy. However, some of their own researches indicated a period of civilized life not less than six thousand years before the fall. "'It is evident that the Maun race is indigenous. They evolved from some lower form of life at one time inhabiting this planet, but now extinct. Their progress was steady, but slow, up till a period about two hundred years before the fall, when rapid scientific progress was made, typical of the entry of the Age of Knowledge with any race. Then, when their advancement had gained great momentum, there appears the references to "the Machine." It should be explained that there is a degree of definiteness in the Maun language which makes a differentiation between the symbol "A" and the symbol "the," though translated identically in the Tharoo language. The symbol "the" is highly definite, meaning a particular or unique individual of the class. Thus there was some particular importance attached to this Machine. "'For some reason it was at first regarded with high suspicion, and it is referred to as "the Machine from beyond." Who invented it is not known. It was, however, capable of thought. For some reason, as unknown as so many things concerning this great, ancient race, the Machine failed, or was destroyed. At any rate, it ceased to function, and as almost the entire basis of their civilization rested on it, the civilization fell.' "He calls that his preliminary discussion," explained San. "The actual report covers many pages. Do you want the rest? I have read it all." "No," said Kahm. "It is enough. With the other things you have told us, I think we understand. The Machine evidently came from beyond Earth, an intelligent Machine, which aided man for a time, and then left again. I do not understand why, as yet. "However that may be, it is evident enough that the Tharoo are not natives of this world, and that our race is; that at one time we developed a great civilization quite independent of the Tharoo, though it evidently fell before their coming. "I think," he said very calmly, quite simply, "we will build it up again. We will first have to convince the Tharoo of our capabilities. "Pol-72, you are in the Eugenics Dispatchment Department. Could you get a few M-type workers to aid us, and a few R-type research workers, also?" Pol-72 smiled softly. "I think so. Call in your servant, Kahm. I will show you something I have learned from certain psychological books. They were written in human tongues before the fall, and even the Tharoo have not translated them." Kahm pressed an annunciator button, and an N-type Maun, a household servant entered quietly. A small man, some five feet five, mentally not well equipped beyond the duties he need know. "He is the best material at hand," said Pol softly. Pol did something very strange. His ten fingers pointing together toward the man at the end of his outstretched hands, his gray eyes narrowed to slits, he rested his feet firmly-and sighed heavily. His face grew somewhat pale beneath its heavy tan, and a strange, soft luminosity, waveringly violet and scarcely visible, played about the tips of his outstretched fingers and seemed to stream like wavering flamelets from his eyes, from the tip of his nose. Thirteen barely visible streams of flowing light, they blended, and pushed, and grew, and drove swift as thought toward the small man who, suddenly pale of face, wide-eyed turned to flee in terror. Gently the wavering banners of light touched him and played about his head. He sank very gently to the floor, and sighed once deeply. For perhaps the tenth part of a second the wavering banners curled like soft violet flames about his head, then died. Panting, exhausted, Pol-72 sank into his chair. "It is-difficult," he said. Silently Kahm was kneeling beside the lax figure on the floor. "He is dead," he reported, beckoning Bar-n to examine him. Pol-72 smiled slightly as the glow of health returned slowly to his pale cheeks. From his pocket, Bar-n, an expert on Life at the Hospital Department, drew a small disk, a thin wire, and a tiny case. The disk he dropped on the lax figure's chest, the wire he plugged into the terminal of the case. They listened, silent There was not the slightest stir of sound. "He is dead," said Bar-n softly. "He is alive," said Pol-72 quietly. "Give me a moment of time-I have practiced little, and there is a great strain. I will explain the thing. In that old book I saw the report of investigations on the radiations of living creatures. Even plants radiate. The radiations of the lowly onion were first discovered. The radiation of one stimulated another. "Later a man found he could kill growing yeast by the radiations his own nervous tissue produced. It is released at the nerve-endings, constantly in most. You know most of our race shun us. That is why. Our radiations are very powerful; they are different, and hence somewhat inimical to those not of our type. The radiation is controllable. The books-the Ancient Ones of our race-did not know that. It is so, however. We have each of us learned to diminish that radiation, to control it, lest we attract unwelcome attention. "I learned to release it, like the stored charge of certain fish which stun their victims by electrical discharges. It is only remotely similar. Largely it is controlled generation. "It is a strain. But I can cause those radiations to drive out from every nerve-ending on my body at will. The nerve-endings are thickly clustered in nose, and eye, and finger-end. Therefore they are the heaviest radiators. The scientists of the Ancient Ones learned that. "They excite even the air. They can stun a lower type Maun into insensibility, or coma, even into death I suspect. But he is not dead. See." Pol-72 pointed but one hand, the bunched fingers like parallel-projector tubes. A thin, scarcely visible light wavered for an instant. The lax figure quivered suddenly, and jerked upright. "Stay there," said Pol-72. The man froze into immobility at the low, incredibly tense words. "You will forget. You will return to your room and sleep. In five minutes you will wake, having forgotten. Go." Like an automaton, the man moved. "When you are ready, Kahm, I will see that whichever ones you wish shall 'die.' Bar-n will receive their bodies for analysis of the reasons of death." For some seconds, silence hung in the room. "You can teach us that thing, Pol?" asked Kahm. Slowly Pol nodded. "I will start certain things at once," continued Kahm. "And San, you are in the Records Department. Have you ever read any Ancient One's writings on the Secret?" San smiled slowly at Kahm. She shook her head as she answered. "Never, Kahm, you know that. I would have said so, had I. I have read every iota of material in the Documents Division, more than any Tharoo, I believe, for as you know, a glance at a page is to know every word and letter on the page, and jto know every thought contained in it. The Secret of Gravity was never written down. The Tharoo would not have searched vainly these many, many hundreds of years had it been there to find. Why, I cannot guess. It was not written." "Perhaps," said Kahm softly, "the Machine brought it, and only the Machine knew it. "Before we can compete, with our small numbers, and without weapons, against the established might of the Tharoo, we must learn many new things. That, I think, is one. "The Tharoo put down a rebellion once. They have not forgotten. San has read of that, and knows how it was done. With great ships, the atomic rocket ships. They have weapons too, though they are never seen. The atomic-blast. You know it, Sahr, in other uses. Tell us what it is." "It is a free atomic-generator blast. The wild fury of a rocket is the atomic-blast tamed, and modified for use. The thousand-foot streamers of ultimate flame that wash away whole mountains to reach some buried ore are the atomic-blast guns controlled, and diminished for useful work. "There are nearly one hundred cruiser ships equipped with the atomic-blast guns. Each ship carries fifteen, of tenth aperture. The greatest mining blasts use a ten-thousandth aperture. They use blast guns no larger, for if even a fifth-inch blast gun were used, the flame would be apt to eat entirely through the thin film of the planet, which is stable rock. Their range is limited on Earth only by the curvature of the planet. Operations from beyond the stratosphere, while the cruisers can readily attain this height, are impossible-for the atomic-blast is destroyed by the one thing in nature which can resist it utterly-the magnetic field of the planet itself in combination with the ionized layer." Kahm spoke again, softly. "So-we have moved swiftly thus far because the Tharoo have not been annoyed by us. Did they so much as imagine we might be somewhat annoying-which they may well, at any instant-they would not, of course, hesitate a fraction of a second in destroying us, and our families. The life of an atom in an atomic-blast is approximately one two-hundred-millionth of a second. "It is growing late now. We have our work. I must make some hand blasts tomorrow for useful burrowing work." Silently, the score went out, down the corridor of metal, down the hundred and seventeen stories to the street, thence home, on the moving walks of the city. Twice Pol-72 bowed his massive head, and crossed his arm in salute to lordly Tharoo. Twice a defiant smile touched the thin, firm lips. Pol-72 knew well that radiations of an intensity that merely stunned an N-class Maun would be instantly fatal to the alien Tharoo. Carefully, he controlled his normal radiation, so that the Tharoo scarcely noted his presence. For, after all, why should he-one among millions? Kahm learned something of Pol-72's technique that next day, for it meant another thing. The conservation of those radiations normally squandered by the nervous system meant a strange, vibrant energy that constantly sustained him. Kahm found he needed some three hours' less sleep. His work had been designed to require a normal man's full time, and ordinarily, Kahm, taking it very easy, fulfilled his tasks in the normal time-and accumulated a good bit of outside data as well. But Kahm, by doing his best, completed what work there was which must be done in less than half the allotted time, yet his fellow workers, interested solely in the work before them, paid little attention, for Kahm was busy throughout the day. Their work was the repair and maintenance of the various complex electronic apparatus of the city, the televisor sets, the intercity and intracity communications apparatus, the automatic apparatus of the ventilators and air conditioners that maintained the great buildings comfortable to their inhabitants, and the countless thousands of small things that needed attention. They did not notice Kahm's work, slow, perhaps, and painfully thoughtful. He was working out something entirely new. The Tharoo had invented the atomic-blast centuries before they left Thar, their home planet. It had powered them across space, and it had built their cities here. It was a mighty thing. So, because they had never seen any need for it, they had not designed a small-scale apparatus. Kahm very much wanted a very private laboratory, and privacy for a Maun was not a thing the Tharoo's plan included. There was but one road to privacy-downward, into the solid rock deep beneath the city. When a Tharoo engineer wanted to tunnel, he used an atomic-blast device weighing some hundreds of tons, and throwing a blast flame capable of destroying several thousand cubic feet of rock a second. It would have brought down a city, of course. Kahm, at the end of the day, had a plan worked out for his new device. At the end of a second day, he had built a cubical box some eighteen inches on a side, and the third day saw the completion of the egg-shaped ellipsoid projector. It was a dirty gray in color, its smooth surface broken in only four places, once by the pistol-grip handle, once for the fifteen-prong connector, once by a tiny jewel that served as a signal-and at one end of the strange thing was a minute pin-prick hole, microscopic in size. Complete, it weighed some ten pounds. Kahm slipped it into a case and took it with him that night. Four of the Rebels met him at his apartment that night, ate with him, and with him descended to the lowest levels of the building where the clicking, humming mechanism of a city under a single roof hummed softly to the song of an atomic generator. Tal was the construction engineer of the group. It took him some twenty minutes to completely interpret the maze of conductors and great girders that criss-crossed beneath the floor of this sub-basement. Then Kahm was ready. The black cube he set on the floor, the thirty-foot length of cord he plugged into the cube, and his eight-inch ellipsoid projector. He touched a stud momentarily, and the ruby jewel on the projector glowed, and from the microscopic aperture of the miniature blast gun a beam shot out-soft, lambent light, prismatic glowings, and tinkling lightnings of some miniature thunderstorm on a miniature stage. The concrete of the wall swirled and writhed in the six-inch cone, boiled slowly, and whirlpooled upward toward the projector, and vanished in silent sparklings. Thin, blue tongues of hydrogen flame, weirdly cold, as the projector sucked out their heat to aid the destruction, leaped once, then burned steadily and straight. "It is slow, Kahm," said Tal after a moment. "It is noiseless," Kahm replied with a faint smile. "I could-and will, later-make it cut a two-foot path at the rate of a foot a second. Then these tiny tinklings become muffled roarings, and the static discharges crackle and snap with power sufficient to fuse a ten-inch bus bar, and the hydrogen gas burns hot instead of cold. "Mam, you had best watch at the elevator controls. If the cars start to descend beyond subbasement E, touch the controls, and tell the occupants of the car that the engineers are working down there." Marn went over to a bank of the clicking, busy relays, and watched closely for some seconds. Then he turned his attention again to the workers, only a fraction of his attention being needed to watch the relays. The men stood outlined in dark against a background of pale-blue, cold light. A hole was growing rapidly in the floor. In twenty minutes, on the low, cable-ridged ceiling of this lowest subbasement, there was a square spot of pale-blue light, wavering and shaken by moving shadows. Marn was alone with the elevator controls. A shaft led down, straight and true, through glassy, hides-cent walls. Only the tops of their heads were visible, and slowly these sank into the ten-foot square shaft. For an instant the blue wavering light died, and Kahm's voice came up. "Marn-Marn-call Doon at his apartment. We will need his work shortly." Marn moved to the communications center and adjusted the controls carefully. Presently a tiny screen lighted with the image of Doon-4- "Doon-4, if your work is done, Kahm can use it now. He has already completed some seven feet of shaft." "I will be there presently," said Doon. It was an hour before he and seven of the others arrived. There was no sign of Kahm now; even the blue light on the ceiling was gone and only the dark, glassy hole remained. But at Marn's call he reappeared presently. In low voices they conferred, and presently the projector, turned down to its tiniest beam, cut ledges in the shaft's rim and drilled holes. From packages Doon and his friends had brought came thin, wonderfully tough metal rods and straps, a collapsible lathework of toughest steels, and a quick-drying cement. An hour more, and a counterbalanced trapdoor had been installed. Then-there was no one in the deepest subbasement For twenty feet the shaft angled sharply down steps, glassy hard, slightly roughened by momentary bursts of the blast. Then it slanted more gently down, and down. The trapdoor was soundproof and now there was a dull, confined roaring, and as a last contingent of the Rebels came on call, bringing more things, a second lead was plugged into the tiny, black cube power plant. A fan whispered to itself in a straight-bored, glass-walled tube that drove sharp and true to the great main ventilator pipe of the building, a half-dozen glow tubes showed white on the walls, and dimmed the pale glory of the blast and the foot-long, noisy lightning. At dawn, the shaft had spiraled down and away nearly a half mile. Kahm did not report to work that day, but Bar-n reported him ill with an infected wound. The others returned that night, with more apparatus, to a corridor nearly two miles long, smooth-floored, dangerously slippery, and descending constantly to a depth of nearly a half mile! At dawn they all climbed up a four-mile slope, a full mile up- ward to the lowest subbasement. But the terminus had been reached. Tal worked the following night, while Kahm slept. When Kahm returned, a tiny car had been constructed, powered by the black cube, running smoothly on the glassy floor, at a sixty-mile speed. The terminus of the tube had widened to five rooms, lighted, cooled, and serviced by a larger power plant, while a larger fan forced the air from the distant giant ventilator of the city. The men rested that night. The women worked. Books, documents, supplies, delicate instruments and chemicals were their contributions. And the following day, Kahm died. At noon Pol came, unobserved, for those who saw him felt a sudden surge of strange power-and forgot. At one o'clock Bar-ii came, examined the body of Kahm, and took it for investigation into the causes of death. Within a dozen hours, a half dozen S- and R-type men and women died, strangely, and Bar-n examined them all for cause of death. They awoke several hours later, beneath the strange glow of Pol's fingers, in rooms of glassy, iridescent walls. They looked into the strange, terrifying eyes of the Rebel, and they forgot all other life, and did as he instructed them. Later they were joined by others, and each night they found more room to work in, and each day they worked with the ellipsoid projector that melted away the rock in pale-blue flames that were cold. And some rock melted away in the transmuters that came, to run out metals, or the elements needed by the miniature food plants that assembled quickly under the swift fingers and machines of the Rebels. In a month, their position was consolidated. The Rebels died then, one by one, save for some three or four who stayed above to bring the things that might be needed and, most of all, information. But all met once each night. "Since mathematics evidently constitutes the main road to advancement in physics, I think this is a wise plan," said Kahm. "This machine is closely similar to those developed in the Ancient Times for mathematics, with improvements possible to us. The Ancients had atomic energy and antigravity. We know their secret of atomic energy was the same as ours. Then it is possible to use this same energy as they did." "Not yet." San smiled. "You haven't done it. What good can it do you if you can?" "I don't know. Our plans must change with every change in our circumstances. "You know-I don't know whether this revolution of ours is humanly possible. There is no known defense against the atomic-blast. Nothing known can stand before it. How then can we fight? Must we destroy all life on the planet in order to destroy the Tharoo? Must we leave only a dead planet as the goal we have won?" "How do you hope to make the antigravity serve you in this?" asked Pol-72. "By teaching me physics. The more I know, the more roads open to me for investigation. It is a secret that the Tharoo never mastered. Only when we have that which they have not, can we definitely point to an advancement over them." "Is the point worth the effort?" 'It takes effort. Yes. It takes time. I agree. We have both. We are a company of the dead. We do not exist, save for you, San, and you, Pol-72, and Reea and Bar-n. You four meet few difficulties in reaching us here. The rest of us no longer are, and the Tharoo have lost all interest or record of us. To the dead, infinity is not too distant. We have time. But we haven't knowledge." This company was not a company of normal humans, but even their superhuman patience and determination must have worn down in the time that elapsed there over a mile beneath the surface of the Earth. It was no question of days or weeks or months. The learning of a thousand years is not to be regained by the experimentation of a day. In medicine, eugenics, chemistry, atomics, electronics and organization they had been trained. Some members of the company were devoted to making plans-slow, careful plans of the action needed when the time came-others, of the organization and psychological groups, to preparing an educational campaign that the Mauns above would understand when the time came, that they might be quickly, and certainly swung into line behind the Rebels. The Rebels were laying out their teachings carefully and cautiously. Mankind was to learn one last great lesson. The lesson of rebellion and freedom. Under the Machine, man had taken an advanced course in indolence, with the inevitable disintegration that follows in every case in all history where man has been allowed indolence. When the Machine left man a perfect world, free of danger or work, man took a postgraduate course in the art of utter laziness. The Tharoo came then, and mankind received such a lesson in labor, work and productivity as the race had never before experienced. Even Mother Nature, in creating the harsh world of evolution, had never equaled the efforts of the Tharoo. It was an excellent course. Man learned work with a thoroughness never before attained. He not merely learned it, but it was bred into the very race. Nature had achieved advancement by making man desire rest and need food. That was a cross pull that kept the race stepping forward with constancy. He worked harder that he might accumulate enough food to rest-and then Nature tricked him by installing decay bacteria to remove his surplus so he couldn't rest. The Tharoo did a better job. They simply bred out the desire for indolence. It was an excellent course that the Tharoo conducted. But they made two mistakes. They taught too well. They taught so well that the pupil excelled the master. And they didn't quite breed out ambition. Which was probably the worst mistake. Because now a new class of teachers had arisen, and they were not only going to teach, but they knew they were going to, and for nearly four long years the Rebels planned, charted, and scheduled their movements. They laid their plans and learned their moves, and calculated the psychological force of their teachings. And the scientists learned slowly those few little dribblings of knowledge that Mother Nature released through her general information bureau, sometimes known as luck, and sometimes as probability. Caesar said: "All Gaul is divided into three parts," and named the inhabitants. Nature keeps her secrets in a series of cabinets, and all knowledge is divided into parts. There are, unfortunately, more than three, but when once the key which permits entry to one cabinet is found-a whole great field of knowledge is discovered and it is all instantly open to rapid exploration. The discovery of the linkage of magnetic and electric fields was one of the keys. In a decade, a terrific advance was made. The discovery of the electron was the key that let into the cabinet of Atomic Knowledge. Kahm found the key to a new cabinet. It was called "Gravitic Fields." It took him four years, three months and eleven days to find it. Two hundred and forty-seven years have passed since that particular day. Garnalt's recent experiments just reached what we might call the lower left-hand back corner of that particular cabinet. It seems to be an unusually large one. Tern-3 was working on some new chemical combinations of the medicines of the Tharoo. Tern had an idea which would have immensely interested the Tharoo. It dealt with the fact that the Tharoo were not a Terrestrial race, despite their long residence on the planet, and that they were not constituted as are humans. Tern-3 had developed a slow-boiling liquid with properties very unpleasant to Tharoo, he believed, yet one which was harmless to humans -unless they stepped directly into the liquid. Tern's work was proceeding nicely; he was just engaged in pouring exactly 245.800 of di-nitro-tri-chlortoluene into his faintly green basic solution-when the faintly green basic solution began to spread itself slowly up the side of the beaker, and Tern-3 felt slightly sick. Simultaneously, the solution he was pouring began to float gently away, across the room, toward the right-hand wall. Tern-3 gurgled gently, and reached for the nearest thing that was firmly anchored. His released beaker floated very gently toward the floor, then stopped, and began to rise slowly. All over his laboratory things were beginning to rise from their places on the tables. There were groans and whimpers of fear from all over the laboratory group. Tern closed his eyes and held on harder as his feet parted company with the floor. He felt himself falling, faster and faster- the smash would be horrible. He must have fallen at least a mile by now. Minute after minute it went on. There was a low growling rumble that Tern noticed suddenly, a stiff thudding pound in the silvery metal stand to which he was clinging. "Kahm!" he called. Not very loud, because he didn't want to open his mouth very widely. He was afraid the result might ruin several of the chemical experiments floating nearby. "Kahm-if you're doing that-I hope you are-the rocks are going to give in a minute." Kahm's voice came back, rather muffled and unhappy. 1 was doing that. I'm not now. If s the machine. It's building up the field. I forgot to hold on, I was so interested, and I'm on the ceiling, and can't reach down to the control. The field's stronger here." "You've ruined several of my mixes," said Tern protesting!/. Tm nearest, I think. I'll try to reach you." Tern let go. He hit the ceiling with a rather decided bump. The force that was lifting him now was evidently growing stronger by the moment. Most of his mixes were resting on the ceiling now, and a number of sizzling, spitting reactions were taking place. Tern walked rapidly across the ceiling, hopping along, Jumping under, through the door, and closing it behind him, for safety. The rocks were groaning very audibly. He dived across the hallway into Kahm's laboratory. Klay-5 was coming from the opposite direction at the same time, also in answer to Kahm's report. The nearer Tern got to the laboratory, the heavier he felt-in the inverted direction. The organization workers at the opposite end of the long laboratory group were appearing in the corridor now, semifloating. There was a definite line of demarcation where the field was strong enough to actually invert gravity and hold the people against the ceiling. In the laboratory, Kahm was on hands and knees now, holding himself away from the ceiling with tremendous effort. The control was nearly ten feet below him. "Impossible," said Tern softly. "Call Gar-i73-G-8," said Kahm. Tern's voice rang out "Yes, master," responded the tremendous voice of the G-8 man, as he appeared in the corridor at the farthermost end. He stood upright, seven and a half feet tall, his tremendous body muscled to the heaviest work. "Come here at once-as swiftly as you can," called Kahm. "The switch," he said, turning his head to Tern, "will fall up another notch in about thirty seconds, and the rate of increase will be doubled." Gar-173 came at his best, a long loping hop that ludicrously carried him into the air in a strange flop that ended with his feet on the ceiling. White-faced, utterly terrified, he came on. His breath was whistling as he reached Tern. "It-it is very wrong," he said. "What must I do?" Kahm spoke to him. Gar stepped across the door frame and into the strange, inverted room. The giant labored forward, his great bones snapping into closer juncture under the terrific strain. "I do not know that I can reach the control, master," he said doubtfully. He was laboring to remain standing against the ceiling as he reached Kahm's side. The great muscles in his arm and shoulder bulged as he attempted to raise his arm far above his head. At last he touched it. Immediately he heaved it upward, straining, three notches. Neutral. The strange, soft sighing of the atomics silenced. Panting, the giant shoved the switch several notches farther. The sighing increased as the atomics took up the load of reversing the power. "That is good," sighed Kahm. The great arm fell heavily to his side, as Gar-173 sank to the ceiling. Slowly the force on the men relaxed. But the deep rumbling of the rocks continued and grew as the weight returned. "The Tharoo will be warned." Kahm sighed. "That was foolish of me. We must work very swiftly." In half an hour Tern and his assistants had made the chemical laboratory habitable once more. In an hour they were at work. Some twenty minutes later San came down the tube, then Pol-72, and finally the two others. "The Tharoo are excited," said Pol-72 mildly. "They do not know exactly how to reach you, but they have located you very accurately. They think it is a strange natural phenomenon. They are already starting with drilling atomic-blasts- they are using the smallest, lest the thing which caused the thing be destroyed." "They will change quickly enough," said Tal, the engineer, "when they detect the cavern by their phonic-sounding apparatus." "I have found something else of interest," sighed Kahm, looking at his instruments. "What they do, they will do. We cannot move, I fear. If we run a large, free atomic-blast for drilling, they will detect it instantly, and cut us off. If we use a small one, they will overtake us. There is really little we can do. Tern and Pol-72 offer our best hope. I must work." Kahm had the key to Nature's cabinet of secrets then. In three hours he had located the exact discrepancy that he had detected in his first readings of the instruments. Bar-n had returned to the surface, and was sending through reports. The Tharoo themselves were in the drilling head, watching the progress of the atomic-blast, but not making phonic soundings as yet, for their destination was still nearly three-quarters of a mile beneath them. "I thought that field built up too swiftly," said Kahm softly. There were five laboratory technicians of types S and R working with him-building a new piece of apparatus. It was larger than the usual portable atomic generator, but it was evidently of the same general type-with a single modification. And the projector that Kahm himself was working over with such infinite care was not like the projectors usually made for drilling, though it too was ellipsoidal. Kahm had much of the apparatus made up for other purposes- for the original experiment. In six hours, therefore, it was ready. Bar-n reported almost si- multaneously that the Tharoo were intensely excited. Phonic soundings had revealed a strange cavern beneath the city, one which had not been there. "And-they report the recent rock shiftings evidently opened a great, slanting fault line extending almost to the surface, and perhaps to the subbasement of building RF-23. Their reports are accurate-if misinterpreted." Bar-11 dodged into the subbasement of the building designated RF-23, and descended the little self-propelled car some ten minutes before the first Tharoo discovered the trapdoor. A detachment of twenty 6-4 guards was sent down at once. They were equipped with the death tubes given only in emergencies. Pol-jz and Bar-n met them at the bottom. Soft, glowing light ringed the twenty fingers of the two men; lambent banners wavered gently toward the group of colossal guardsmen. Silently, gently, the twenty giants slumped to the smooth floor of the corridor. Ten minutes later they re-ascended the corridor, two S-type Mauns of the Organization group in their clutches. At the top of the corridor, a group of some thirty Tharoo and a dozen M-type intelligent laborers greeted them. The thirty Tharoo slumped, clawing at their breasts, as the death tubes glowed momentarily. The M-type Mauns looked on in amazement, and at the gesture of the guard commander, a type 6-14 Maun, they preceded the guards down the tube, for they knew, from lifelong teaching, that Mauns of all types and classes must obey the G-types when ordered by them to go. It was nearly an hour before a group of Tharoo and guards discovered the dead Tharoo at the head of the shaft. Instantly a thousand messages radiated from the subbasement of RF-23. A detachment of thirty 6-4 guardsmen under two 6-14 officers was at once sent down the shaft. Half an hour passed. The detachment returned, slowly climbing the tube, with ten S- and R-type Mauns and a few M-types. The Tharoo started forward eagerly to question them. Thirty-two death tubes raised as one, and silently the Tharoo fell dead to the floor. Five R-type Maun scientists had been with them and, half-rebellious, half-understanding the words of the R-type men who had come up with the guards, they went silently down with the guards. The Tharoo of that day did not know what rebellion was-they had never really pictured it. Now they could not guess what had caused this strange disap- pearance and death, when a third detachment was rushed to the scene. They guessed wildly. Rebellion they could not imagine. Some strange natural force, associated with the recent rock shift, and the strange antigravitational force. A terrible gas released far beneath the ground, one which dissolved away every trace of the Mauns, perhaps, in an hour or two, but one which, due to the different structure of the Tharoo, merely coagulated their protein flesh, as did a death tube. The next detachment wore gas masks, and stayed several floors above, watching the 6-4 guards and R-type Maun research workers by televisor. They saw them go down. They saw the R-type Mauns remain at the surface. The G-4S were gone half an hour-an hour-two hours. Still nothing happened. A larger group of 6-4 guards went down, accompanied by several R-type Mauns. Nothing happened. Two hours more, and they did not return. In desperation, the Tharoo sent still another group, and they were equipped with a little truck carrying a complete televisor apparatus. But suddenly, when they had descended some three miles or more, the televisor apparatus began to function poorly; interference built up in the wires trailing behind, and recall signals sent to the men below did not reach them at all. At last, a few brave Tharoo volunteered to descend the great tube. They went armed with a portable atomic-blast and they went slowly for they ran that blast every inch of the way, enlarging the tube, but destroying any chance form of life or gas that might be there. One-two-three-three and a half miles they went, their blast following the curved outline of the tube, enlarging it, tending to straighten it. At three and three-quarters miles they stopped, left their blast running, and retreated, terrified up the tube, leaving only a group of type-R Mauns to investigate. The blast washed harmlessly against an invisible surface! The pale beam, the tiny, lambent lightnings crackled and sang, twittered against the rock, and swiftly enlarged it. But like a great round plug in the tube, there was a wall that drank up the terrible force of the atomic-blast and turned it silently, effortlessly, into utter darkness. At fullest aperture the beam roared, the rock washed away in great spurting bursts of flaming hydrogen, the lightnings became mighty blasts that shook the very heart of the rock-then at last all was quiet and terror was gone, save where that strange silence held grimly, horribly mysterious. There was no sound, no light, no discharge, only the quiet sucking in of the atomic-blast-and silence. They waited for a report from those Maun investigators they had left, and no report came, and the beam continued on for hour after hour. The Tharoo went down cautiously. The silence was there. The Maun investigators were gone. Tharoo scientists went down then. They had to. Only that deadly, inexplicable disappearance of Mauns and the silent, inexplicable death of Tharoo went on. The second day another group of Tharoo went down to see what had happened to the Tharoo scientists. They lay there-dead. The Mauns were gone again, and the Tharoo this time were not coagulated but simply dead, without reason or understanding. Vi-tameters, delicate things capable of showing the least trace of life, showed only that every single cell of the body was dead. Not as in ordinary death, where muscles live for hours, and hair cells live for months after death. Everything was dead. The televisor would not work here. The silence stopped it somehow. Every form of electrical shielding was tried, and the silence drank in the shielding. They brought down the mightiest atomic-blasts they knew, and the silence took them into itself, and the roaring and crackling of the lightnings died. There was only one way. A chain of Tharoo stood all down that corridor. Whatever else they may have been, the Tharoo had courage, and in the face of that utterly inexplicable mystery, they stood up to it, to learn its secret. They retreated hastily though when the silence changed; it grew slowly dark, and the white light of the tubes beyond dimmed slowly. They believed the first expedition to go down had set those tubes in the wall for light, and there was none to contradict them. Their powerful light beams died out into darkness when they touched the spherical wall of the silence. Mauns were left there to watch. The Tharoo retreated till they could just see them around the bend of the corridor. For almost an hour they waited while nothing happened. Then-out of the silence came strange, soft banners and flames of violet haze that slowly wound around the heads of the suddenly fleeing Mauns, and the Mauns fell. Hastily the Tharoo retreated farther around the bend. Cautiously a Maun observer poked his head around the corner. The Tharoo watching him saw only the slowly slumping body, the crumpling limbs. He cried out in terror. However, silently, wordlessly, the Maun gathered his limbs under him, like a revived corpse and, still with the strange stiffness of automatic movement, walked around that corner. The Tharoo did not see him, but he saw his reflection in the glassy wall of the corridor as he joined the stiffly standing group of Mauns and, without a sound or word, marched with them into and through the silence. A Tharoo was sent then-a hopeless cripple who sought death as a relief-to observe, and if possible, report. He observed only the silence hour after hour, and when he attempted to analyze it, he gave only a faint sigh. A cable pulled back his body. The vitameter showed every cell dead, yet no slightest reason for death. The cells were not burned, nor was he injured. They were apparently as sound as they had been-but they were dead. That day the silence moved. It expanded slowly; it swallowed the atomic-blast machine, then the corner where the Tharoo had watched. It stopped finally when, as the Tharoo presently observed, it was of such a radius, that the spherical surface of it reached the ground surface directly above the center of the disturbance. In terror the Tharoo attacked it. They attacked it with their mightiest war blasts, with giant bombs, with atomic engines and conductor beams that sent mighty flaming arcs ten thousand feet into the air-and vanished soundless, lightless, in the silence. The terror spread. It spread slowly and evenly, engulfing more and more of the city. Mauns and Tharoo alike fled from it. Kahm smiled faintly at the city beyond. He stood at the mouth of the new bore, a straight, round tube fifty feet across. The walls were not glassy and hard, but smooth, cold, gray granite. It came out in the center of the Landing Place. To the right was the Temple of the Landing. It was fitting. The Rebels had landed on Earth's surface within one hundred feet of the spot where the Tharoo had landed. There was a semicircular clearing, at the moment uninhabited. Beyond, shimmering very, very slightly, lay the great city, towering in scarlet, silver, gold and ebony metal. And at the edge Mauns and Tharoo milled and retreated. There were scores of men working about in the quarter-mile circle within the wavering, nearly invisible dome, patching and filling the great, glassy scars and holes where the mighty atomic bombs had loosed their flaming energies in scintillating, poppy-red flares, sparkling with the typical violet pinpoints of bursting atoms. The only sound was a faint tinkling as of crashing fairy goblets. There were more burstings outside now, near the wall. Above, three great atomic cruisers hung, their great blasts roaring a patch of inconceivable Titan's anger across the sky, to vanish quiet as death into the shimmering curtain. Outside, the shimmering curtain was a black dome, a dome as dark as platinum-black, since it was utterly absorbent to all light that struck it from the outside, passing it freely, and utterly impenetrable to all light that struck it from the inside. Kahm turned his eyes toward San, smiling. "Your Organization Department was partly wrong. It has been wonderfully successful in gaining time for us. The psychological work was perfect-the Tharoo are utterly mystified. But we cannot advance this dome in this way, continually driving every one away. We need the city. They are destroying it." "If you advanced much more rapidly, the Tharoo would not have time to save the Mauns. Nor would they have time to fight, which is what we want. That is the new suggestion of the Organizers," replied San. Kahm nodded slowly. "That was the plan I had in mind. I wanted their approval independently, however. I will start. Also, I think I will destroy those cruisers, for that will aid us in saving the city from ruin." Kahm returned to the edge of the great tube. A steady, quite powerful wind rose from it. Kahm picked up a small, square case shaped to fit his powerful shoulders and strapped it on. In a moment he was diving down the tube at terrific speed, slowing at the bottom, as he reversed the attraction of gravity. San slowed beside him and landed almost at the same instant. Together, they went to the laboratory where Kahm had worked. It was a mass of powerful machinery grouped about a cube of gold and blue and black, the heart of their power. There was a slow, steady-moving wheel here, a great time drive that was advancing the wall of the silence inexorably. Kahm made an adjustment. The wheel suddenly accelerated to five times its former pace. In a few minutes Kahm was back at the surface. The people on the outskirts of the curtain had not noticed the accelerated growth as yet. They only knew it was growing. Kahm turned his eyes upward. Three great cruisers hung there, dropping bombs and splitting their rays. Kahm raised a little ellipsoidal projector in his hand, looked at it for a moment, then sighted along the thin metal rod at its top, and slowly depressed a button. The Tharoo saw the black dome leap suddenly upward at one point, an utterly black finger driving with the speed of light toward a cruiser. It barely touched it-and collapsed. For ten seconds the cruiser hung there, her atomic-blasts suddenly stilled, the bombs no longer dropping. She hung there, apparently sound. It took some time for the atomically fine dust to spread about enough for them to see at that distance that she was no longer a cruiser, but a dust cloud in the shape of a cruiser. The shape held fairly well for nearly two minutes. Most of them had shifted their gaze, however, before then. The second and third cruisers were slowly expanding. The dust was ultramicroscopic in size, colloidal even in air. It never settled. It floats about Earth today, in all probability. Then they saw the swifter growth of the curtain. It was growing still faster now. The Tharoo promptly preempted all means of transit. Some of the Tharoo were too slow and, with the tens of thousands of Mauns, vanished into the curtain. The Mauns were greeted by those who had preceded them into the curtain. Safe within, utterly bewildered and lost, finding suddenly that within it was quiet and light and the city was undisturbed. G-type men took charge of the groups, familiar giant figures of solidity and orderliness. They moved in orderly groups to their places, many returning to their homes, now safe within the Dome. Lordly Tharoo were different. Terrified and fleeing, they were caught by the Dome, struggled for an instant-and burst through to light and freedom to an orderly, cleared place where 6-4 men worked and tended and directed. Their courage renewed, they demanded attention. Instantly, the 6-14 guard officers directed them, quite as though they had been Mauns, to go to the central clearing. They were angry. They were insulted by the fact these Mauns did not address them as "Tharoo Master." But they were bewildered. They went. There were four Mauns there. Four of a type not quite like anything they had seen. Tall and powerful, their faces keenly, intensely intelligent, their eyes gray and disconcertingly intense. Granth Marld was the first to reach the four. "Mauns, what is this? Who is responsible for this thing?" Kahm answered, smiling faintly. "We are, Tharoo. We are taking back our world. This was our world. It shall be our world. The Tharoo can go to Venus, for our records show that once, when you had just landed, you knew that another group of your race had gone to Venus. That was forgotten in the press of things and now you have forgotten it all together. "We do not intend to kill unnecessarily. You will leave our planet, however." The Tharoo inclined his head and gazed at the impudent human with all three eyes. "Maun, what imbecility is this? Mauns-Mauns -instructing Tharool" He trembled-his arms shook vaguely in his utter stupefaction, his inability to explain the impossibility of the outrageous idea. Kahm smiled slowly. "You will move to Venus. I hope there is no race there already, that your Tharoo race has enslaved. Still, you did help us, and for that we do not take the easiest course-and simply destroy you." The Tharoo seemed suddenly to quiet down. His excitement passed. "I was upset evidently. That blackness is mystifying from the other side. Interesting. It withstands the atomic-blast. "But you-and your wild ideas. It is evident that you are a defective type, with nervous instability of the hundredth order. Completely beyond reason. You will immediately report to the Tharoo Head. Gar"-he turned to the giant 6-14 standing beside him- "take this Maun to the Tharoo Head at once." The giant smiled down slowly at the Tharoo. He glanced up at Kahm, smiling, too. "No, Tharoo. You do not understand. The Maun race is the stronger. The Tharoo are finished. They are to go," he said slowly. Kahm spoke: "The Tharoo are finished. This is our world. We are taking it back. You thought me perhaps an R- or S-type? I am not. I am a type created by an R-type Eugenist that the Mauns might win back their world. My type is thirty-seven degrees higher, which makes it seven degrees higher than the Tharoo believed possible, for the Tharoo rate but ninety-five degrees themselves. We are of a much higher type than the Tharoo." The Tharoo stared at him in amazement. He stared at the guard slowly. "Does the curtain produce this insanity in all who pass through it? Great Mahgron-a Maun type higher than a Tharoo! "Maun, stay here," he said in final sharp decision. "I must bring others to take care of this." He turned, and started away determinedly. "Tharoo," called Kahm softly. One of the Tharoo's three eyes focused on Kahm. "Stay," said Kahm gently. The outstretched finger of Kahm's hand glowed very, very faintly. The Tharoo stiffened suddenly. His eye turned wildly in its orbit, his other eyes swung suddenly on Kahm. Tiny, almost invisible streamers of haze hung about the Tharoo's head and shoulders. He stopped. Slowly he turned, and looked up toward Kahm. "Aye-Maun," he said very faintly. Very slowly he slumped down. The ribbons and streamers left him, as Kahm's hand dropped. Kahm turned to Pol-yz. "We cannot rouse him, for our radiations are deadly to him. Will he rouse of himself?" asked the physicist. "I think so. But-I fear he will be mindless. The struggle probably blasted his mind completely." Half an hour later he awoke, mindless, as Pol had said. Stronger streamers of strange luminescence swept from Pol's fingers, and he passed into eternal unconsciousness. Others came, though, who fought not quite so stubbornly, and awoke again, sane. They looked and, as one after another of their race fell as inevitably as before death, they slowly grasped that man had developed beyond them. When the slightest wavering haze brought their strongest down, and when on one occasion a Tharoo attempted to attack, they saw the forty fingers rise, and from them shot a driving, scintillating stream of solid luminescence that blasted the Tharoo into instant, utter death. It was a hard lesson. Only the young among them learned it, those young who had been cared for and largely tutored by Maun S- and R-types, and had already learned from Mauns-those learned the lesson and remembered it. In a week the Dome covered Landing City. "You have, then, learned to treat with us," said Kahm softly. There were ten Tharoo there, from the ten greatest cities of the Tharoo still remaining. They were all young. The old Tharoo were aware of that fact. They could not endure it, however. "Aye, Maun," said a grave representative of the Tharoo. "We must learn what you mean us to do." "You have in your records the fact that the other ship which accompanied the ship in which your forefathers landed went on to Venus. Never have your two branches met, or joined. I would advise that you seek them. You may be welcome there. "You may go, and take all your ships. You have learned, I believe, that we could stop any ship leaving which we did not care to tave go. But no Maun-either male or female-of any type or class, age or size may you take with you. Mauns are to be a free race. Do you understand?" "Aye-in general. But we must work out the plans, in detail still.*' "That can only be done after a party has been sent to Venus," replied Kahm steadily. There was a celebration when the last ship left for Venus with the last group of Tharoo. The counsels and representatives still remained. There was still intense enmity. But it was closely bottled up, for only the Mauns were in a position to do anything about it, and they were content. The Mauns, be it understood, had both the irresistible force and the immovable object, and because they were a strange race, of different types, all contented with the work which they must do and inasmuch as they had been bred with that in view, there was little chance of turning one against each other. The Tharoo, welcome enough on Venus where their race had, in fighting a desperately savage jungle alone-not with the aid of a tractable race-lost all their science and comfort, nevertheless far preferred the Earth where they were not welcome. They preferred it even more, when they discovered the exact meaning of work. But -what was to be done against the curtain? Actually it came down to the question: "What was to be done against a more intelligent race?" For the Tharoo were excellent teachers.