The Talking Robot was a tour de force, a thoroughly impractical device, possessing publicity value only. Once an hour, an escorted group stood before it and asked questions of the robot engineer in charge in careful whispers. Those the engineer decided were suitable for the robot’s circuits were transmitted to the Talking Robot.
   It was rather dull. It may be nice to know that the square of fourteen is one hundred ninety-six, that the temperature at the moment is 72 degrees Fahrenheit, and the air-pressure 30.02 inches of mercury, that the atomic weight of sodium is 23, but one doesn’t really need a robot for that. One especially does not need an unwieldy, totally immobile mass of wires and coils spreading over twenty-five square yards.
   Few people bothered to return for a second helping, but one girl in her middle teens sat quietly on a bench waiting for a third. She was the only one in the room when Gloria entered.
   Gloria did not look at her. To her at the moment, another human being was but an inconsiderable item. She saved her attention for this large thing with the wheels. For a moment, she hesitated in dismay. It didn’t look like any robot she had ever seen.
   Cautiously and doubtfully she raised her treble voice; “Please, Mr. Robot, sir, are you the Talking Robot, sir?” She wasn’t sure, but it seemed to her that a robot that actually talked was worth a great deal of politeness.
   (The girl in her mid-teens allowed a look of intense concentration to cross her thin, plain face. She whipped out a small notebook and began writing in rapid pothooks.)
   There was an oily whir of gears and a mechanically timbered voice boomed out in words that lacked accent and intonation, “I—am—the—robot—that—talks.”
   Gloria stared at it ruefully. It did talk, but the sound came from inside somewheres. There was no face to talk to. She said, “Can you help me, Mr. Robot, sir?”
   The Talking Robot was designed to answer questions, and only such questions as it could answer had ever been put to it. It was quite confident of its ability, therefore, “I—can—help—you.”
   “Thank you, Mr. Robot, sir. Have you seen Robbie?”
   “Who is Robbie?”
   “He’s a robot, Mr. Robot, sir.” She stretched to tiptoes. “He’s about so high, Mr. Robot, sir, only higher, and he’s very nice. He’s got a head, you know. I mean you haven’t, but he has, Mr. Robot, sir.”
   The Talking Robot had been left behind, “A—robot?”
   “Yes, Mr. Robot, sir. A robot just like you, except he can’t talk, of course, and—looks like a real person.”
   “A—robot—like—me?”
   “Yes, Mr. Robot, sir.”
   To which the Talking Robot’s only response was an erratic splutter and an occasional incoherent sound. The radical generalization offered it, i.e., its existence, not as a particular object, but as a member of a general group, was too much for it. Loyally, it tried to encompass the concept and half a dozen coils burnt out. Little warning signals were buzzing.
   (The girl in her mid-teens left at that point. She had enough for her Physics-1 paper on “Practical Aspects of Robotics.” This paper was Susan Calvin’s first of many on the subject.)
   Gloria stood waiting, with carefully concealed impatience, for the machine’s answer when she heard the cry behind her of “There she is,” and recognized that cry as her mother’s.
   “What are you doing here, you bad girl?” cried Mrs. Weston, anxiety dissolving at once into anger. “Do you know you frightened your mamma and daddy almost to death? Why did you run away?”
   The robot engineer had also dashed in, tearing his hair, and demanding who of the gathering crowd had tampered with the machine. “Can’t anybody read signs?” he yelled. “You’re not allowed in here without an attendant.”
   Gloria raised her grieved voice over the din, “I only came to see the Talking Robot, Mamma. I thought he might know where Robbie was because they’re both robots.” And then, as the thought of Robbie was suddenly brought forcefully home to her, she burst into a sudden storm of tears, “And I got to find Robbie, Mamma. I got to.”
   Mrs. Weston strangled a cry, and said, “Oh, good Heavens. Come home, George. This is more than I can stand.”
   That evening, George Weston left for several hours, and the next morning, he approached his wife with something that looked suspiciously like smug complacence.
   “I’ve got an idea, Grace.”
   “About what?” was the gloomy, uninterested query?
   “About Gloria.”
   “You’re not going to suggest buying back that robot?”
   “No, of course not.”
   “Then go ahead. I might as well listen to you. Nothing I’ve done seems to have done any good.”
   “All right. Here’s what I’ve been thinking. The whole trouble with Gloria is that she thinks of Robbie as a person and not as a machine. Naturally, she can’t forget him. Now if we managed to convince her that Robbie was nothing more than a mess of steel and copper in the form of sheets and wires with electricity its juice of life, how long would her longings last? It’s the psychological attack, if you see my point.”
   “How do you plan to do it?”
   “Simple. Where do you suppose I went last night? I persuaded Robertson of U. S. Robots and Mechanical Men, Inc. to arrange for a complete tour of his premises tomorrow. The three of us will go, and by the time we’re through, Gloria will have it drilled into her that a robot is not alive.”
   Mrs. Weston’s eyes widened gradually and something glinted in her eyes that was quite like sudden admiration, “Why, George, that’s a good idea.”
   And George Weston’s vest buttons strained. “Only kind I have,” he said.
   Mr. Struthers was a conscientious General Manager and naturally inclined to be a bit talkative. The combination, therefore, resulted in a tour that was fully explained, perhaps even over-abundantly explained, at every step. However, Mrs. Weston was not bored. Indeed, she stopped him several times and begged him to repeat his statements in simpler language so that Gloria might understand. Under the influence of this appreciation of his narrative powers, Mr. Struthers expanded genially and became ever more communicative, if possible.
   George Weston, himself, showed a gathering impatience.
   “Pardon me, Struthers,” he said, breaking into the middle of a lecture on the photoelectric cell, “haven’t you a section of the factory where only robot labor is employed?”
   “Eh? Oh, yes! Yes, indeed!” He smiled at Mrs. Weston. “A vicious circle in a way, robots creating more robots. Of course, we are not making a general practice out of it. For one thing, the unions would never let us. But we can turn out a very few robots using robot labor exclusively, merely as a sort of scientific experiment. You see,” he tapped his pince-nez into one palm argumentatively, “what the labor unions don’t realize—and I say this as a man who has always been very sympathetic with the labor movement in general—is that the advent of the robot, while involving some dislocation to begin with, will inevitably—”
   “Yes, Struthers,” said Weston, “but about that section of the factory you speak of—may we see it? It would be very interesting, I’m sure.”
   “Yes! Yes, of course!” Mr. Struthers replaced his pince-nez in one convulsive movement and gave vent to a soft cough of discomfiture. “Follow me, please.”
   He was comparatively quiet while leading the three through a long corridor and down a flight of stairs. Then, when they had entered a large well-lit room that buzzed with metallic activity, the sluices opened and the flood of explanation poured forth again.
   “There you are!” he said with pride in his voice. “Robots only! Five men act as overseers and they don’t even stay in this room. In five years, that is, since we began this project, not a single accident has occurred. Of course, the robots here assembled are comparatively simple, but … “
   The General Manager’s voice had long died to a rather soothing murmur in Gloria’s ears. The whole trip seemed rather dull and pointless to her, though there were many robots in sight. None were even remotely like Robbie, though, and she surveyed them with open contempt.
   In this room, there weren’t any people at all, she noticed. Then her eyes fell upon six or seven robots busily engaged at a round table halfway across the room. They widened in incredulous surprise. It was a big room. She couldn’t see for sure, but one of the robots looked like—looked like—it was!
   “Robbie!” Her shriek pierced the air, and one of the robots about the table faltered and dropped the tool he was holding. Gloria went almost mad with joy. Squeezing through the railing before either parent could stop her, she dropped lightly to the floor a few feet below, and ran toward her Robbie, arms waving and hair flying.
   And the three horrified adults, as they stood frozen in their tracks, saw what the excited little girl did not see,—a huge, lumbering tractor bearing blindly down upon its appointed track.
   It took split-seconds for Weston to come to his senses, and those split-seconds meant everything, for Gloria could not be overtaken. Although Weston vaulted the railing in a wild attempt, it was obviously hopeless. Mr. Struthers signaled wildly to the overseers to stop the tractor, but the overseers were only human and it took time to act.
   It was only Robbie that acted immediately and with precision.
   With metal legs eating up the space between himself and his little mistress he charged down from the opposite direction. Everything then happened at once. With one sweep of an arm, Robbie snatched up Gloria, slackening his speed not one iota, and, consequently, knocking every breath of air out of her. Weston, not quite comprehending all that was happening, felt, rather than saw, Robbie brush past him, and came to a sudden bewildered halt. The tractor intersected Gloria’s path half a second after Robbie had, rolled on ten feet further and came to a grinding, long drawn-out stop.
   Gloria regained her breath, submitted to a series of passionate hugs on the part of both her parents and turned eagerly toward Robbie. As far as she was concerned, nothing had happened except that she had found her friend.
   But Mrs. Weston’s expression had changed from one of relief to one of dark suspicion. She turned to her husband, and, despite her disheveled and undignified appearance, managed to look quite formidable, “You engineered this, didn’t you?
   George Weston swabbed at a hot forehead with his handkerchief. His hand was unsteady, and his lips could curve only into a tremulous and exceedingly weak smile.
   Mrs. Weston pursued the thought, “Robbie wasn’t designed for engineering or construction work. He couldn’t be of any use to them. You had him placed there deliberately so that Gloria would find him. You know you did.”
   “Well, I did,” said Weston. “But, Grace, how was I to know the reunion would be so violent? And Robbie has saved her life; you’ll have to admit that. You can’t send him away again.”
   Grace Weston considered. She turned toward Gloria and Robbie and watched them abstractedly for a moment. Gloria had a grip about the robot’s neck that would have asphyxiated any creature but one of metal, and was prattling nonsense in half-hysterical frenzy. Robbie’s chrome-steel arms (capable of bending a bar of steel two inches in diameter into a pretzel) wound about the little girl gently and lovingly, and his eyes glowed a deep, deep red.
   “Well,” said Mrs. Weston, at last, “I guess he can stay with us until he rusts.”
   Susan Calvin shrugged her shoulders, “Of course, he didn’t. That was 1998. By 2002, we had invented the mobile speaking robot which, of course, made all the non-speaking models out of date, and which seemed to be the final straw as far as the non-robot elements were concerned. Most of the world governments banned robot use on Earth for any purpose other than scientific research between 2003 and 2007.”
   “So that Gloria had to give up Robbie eventually?”
   “I’m afraid so. I imagine, however, that it was easier for her at the age of fifteen than at eight. Still, it was a stupid and unnecessary attitude on the part of humanity. U. S. Robots hit its low point, financially; just about the time I joined them in 2007. At first, I thought my job might come to a sudden end in a matter of months, but then we simply developed the extra-Terrestrial market.”
   “And then you were set, of course.”
   “Not quite. We began by trying to adapt the models we had on hand. Those first speaking models, for instance. They were about twelve feet high, very clumsy and not much good. We sent them out to Mercury to help build the mining station there, but that failed.”
   I looked up in surprise, “It did? Why, Mercury Mines is a multi-billion dollar concern.”
   “It is now, but it was a second attempt that succeeded. It you want to know about that, young man, I’d advise you to look up Gregory Powell. He and Michael Donovan handled our most difficult cases in the teens and twenties. I haven’t heard from Donovan in years, but Powell is living right here in New York. He’s a grandfather now, which is a thought difficult to get used to. I can only think of him as a rather young man. Of course, I was younger, too.”
   I tried to keep her talking, “If you would give me the bare bones, Dr. Calvin, I can have Mr. Powell fill it in afterward.” (And this was exactly what I later did.)
   She spread her thin hands out upon the desk and looked at them. “There are two or three,” she said, “that I know a little about.”
   “Start with Mercury,” I suggested.
   “Well, I think it was in 2015 that the Second Mercury Expedition was sent out. It was exploratory and financed in part by U. S. Robots and in part by Solar Minerals. It consisted of a new-type robot, still experimental; Gregory Powell, Michael Donovan—”

Runaround

   It was one of Gregory Powell’s favorite platitudes that nothing was to be gained from excitement, so when Mike Donovan came leaping down the stairs toward him, red hair matted with perspiration, Powell frowned.
   “What’s wrong?” he said. “Break a fingernail?”
   “Yaaaah,” snarled Donovan, feverishly. “What have you been doing in the sublevels all day?” He took a deep breath and blurted out, “Speedy never returned.”
   Powell’s eyes widened momentarily and he stopped on the stairs; then he recovered and resumed his upward steps. He didn’t speak until he reached the head of the flight, and then:
   “You sent him after the selenium?”
   “Yes.”
   “And how long has he been out?”
   “Five hours now.”
   Silence! This was a devil of a situation. Here they were, on Mercury exactly twelve hours—and already up to the eyebrows in the worst sort of trouble. Mercury had long been the jinx world of the System, but this was drawing it rather strong—even for a jinx.
   Powell said, “Start at the beginning, and let’s get this straight.”
   They were in the radio room now—with its already subtly antiquated equipment, untouched for the ten years previous to their arrival. Even ten years, technologically speaking, meant so much. Compare Speedy with the type of robot they must have had back in 2005. But then, advances in robotics these days were tremendous. Powell touched a still gleaming metal surface gingerly. The air of disuse that touched everything about the room—and the entire Station—was infinitely depressing.
   Donovan must have felt it. He began: “I tried to locate him by radio, but it was no go. Radio isn’t any good on the Mercury Sunside—not past two miles, anyway. That’s one of the reasons the First Expedition failed. And we can’t put up the ultrawave equipment for weeks yet—”
   “Skip all that. What did you get?”
   “I located the unorganized body signal in the short wave. It was no good for anything except his position. I kept track of him that way for two hours and plotted the results on the map.”
   There was a yellowed square of parchment in his hip pocket—a relic of the unsuccessful First Expedition—and he slapped it down on the desk with vicious force, spreading it flat with the palm of his hand. Powell, hands clasped across his chest, watched it at long range.
   Donovan’s pencil pointed nervously. “The red cross is the selenium pool. You marked it yourself.”
   “Which one is it?” interrupted Powell. “There were three that MacDougal located for us before he left.”
   “I sent Speedy to the nearest, naturally; seventeen miles away. But what difference does that make?” There was tension in his voice. “There are the penciled dots that mark Speedy’s position.”
   And for the first time Powell’s artificial aplomb was shaken and his hands shot forward for the map.
   “Are you serious? This is impossible.”
   “There it is,” growled Donovan.
   The little dots that marked the position formed a rough circle about the red cross of the selenium pool. And Powell’s fingers went to his brown mustache, the unfailing signal of anxiety.
   Donovan added: “In the two hours I checked on him, he circled that damned pool four times. It seems likely to me that he’ll keep that up forever. Do you realize the position we’re in?”
   Powell looked up shortly, and said nothing. Oh, yes, he realized the position they were in. It worked itself out as simply as a syllogism. The photocell banks that alone stood between the full power of Mercury’s monstrous sun and themselves were shot to hell.
   The only thing that could save them was selenium. The only thing that could get the selenium was Speedy. If Speedy didn’t come back, no selenium. No selenium, no photocell banks. No photo-banks—well, death by slow broiling is one of the more unpleasant ways of being done in.
   Donovan rubbed his red mop of hair savagely and expressed himself with bitterness. “We’ll be the laughingstock of the System, Greg. How can everything have gone so wrong so soon? The great team of Powell and Donovan is sent out to Mercury to report on the advisability of reopening the Sunside Mining Station with modern techniques and robots and we ruin everything the first day. A purely routine job, too. We’ll never live it down.”
   “We won’t have to, perhaps,” replied Powell, quietly. “If we don’t do something quickly, living anything down—or even just plain living—will be out of the question.”
   “Don’t be stupid! If you feel funny about it, Greg, I don’t. It was criminal, sending us out here with only one robot. And it was your bright idea that we could handle the photocell banks ourselves.”
   “Now you’re being unfair. It was a mutual decision and you know it. All we needed was a kilogram of selenium, a Stillhead Dielectrode Plate and about three hours’ time and there are pools of pure selenium all over Sunside. MacDougal’s spectroreflector spotted three for us in five minutes, didn’t it? What the devil! We couldn’t have waited for next conjunction.”
   “Well, what are we going to do? Powell, you’ve got an idea. I know you have, or you wouldn’t be so calm. You’re no more a hero than I am. Go on, spill it!”
   “We can’t go after Speedy ourselves, Mike—not on the Sunside. Even the new insosuits aren’t good for more than twenty minutes in direct sunlight. But you know the old saying, ‘Set a robot to catch a robot’ Look, Mike, maybe things aren’t so bad. We’ve got six robots down in the sublevels, that we may be able to use, if they work. If they work.”
   There was a glint of sudden hope in Donovan’s eyes. “You mean six robots from the First Expedition. Are you sure? They may be subrobotic machines. Ten years is a long time as far as robot-types are concerned, you know.”
   “No, they’re robots. I’ve spent all day with them and I know. They’ve got positronic brains: primitive, of course.” He placed the map in his pocket. “Let’s go down.”
   The robots were on the lowest sublevel—all six of them surrounded by musty packing cases of uncertain content. They were large, extremely so, and even though they were in a sitting position on the floor, legs straddled out before them, their heads were a good seven feet in the air.
   Donovan whistled. “Look at the size of them, will you? The chests must be ten feet around.”
   “That’s because they’re supplied with the old McGuffy gears. I’ve been over the insides—crummiest set you’ve ever seen.”
   “Have you powered them yet?”
   “No. There wasn’t any reason to. I don’t think there’s anything wrong with them. Even the diaphragm is in reasonable order. They might talk.”
   He had unscrewed the chest plate of the nearest as he spoke, inserted the two-inch sphere that contained the tiny spark of atomic energy that was a robot’s life. There was difficulty in fitting it, but he managed, and then screwed the plate back on again in laborious fashion. The radio controls of more modern models had not been heard of ten years earlier. And then to the other five.
   Donovan said uneasily, “They haven’t moved.”
   “No orders to do so,” replied Powell, succinctly. He went back to the first in the line and struck him on the chest. “You! Do you hear me?”
   The monster’s head bent slowly and the eyes fixed themselves on Powell. Then, in a harsh, squawking voice—like that of a medieval phonograph, he grated, “Yes, Master!”
   Powell grinned humorlessly at Donovan. “Did you get that? Those were the days of the first talking robots when it looked as if the use of robots on Earth would be banned. The makers were fighting that and they built good, healthy slave complexes into the damned machines.”
   “It didn’t help them,” muttered Donovan.
   “No, it didn’t, but they sure tried.” He turned once more to the robot. “Get up!”
   The robot towered upward slowly and Donovan’s head craned and his puckered lips whistled.
   Powell said: “Can you go out upon the surface? In the light?”
   There was consideration while the robot’s slow brain worked. Then, “Yes, Master.”
   “Good. Do you know what a mile is?”
   Another consideration, and another slow answer. “Yes, Master.”
   “We will take you up to the surface then, and indicate a direction. You will go about seventeen miles, and somewhere in that general region you will meet another robot, smaller than yourself. You understand so far?”
   “Yes, Master.”
   “You will find this robot and order him to return. If he does not wish to, you are to bring him back by force.”
   Donovan clutched at Powell’s sleeve. “Why not send him for the selenium direct?”
   “Because I want Speedy back, nitwit. I want to find out what’s wrong with him.” And to the robot, “All right, you, follow me.”
   The robot remained motionless and his voice rumbled: “Pardon, Master, but I cannot. You must mount first.” His clumsy arms had come together with a thwack, blunt fingers interlacing.
   Powell stared and then pinched at his mustache. “Uh … oh!”
   Donovan’s eyes bulged. “We’ve got to ride him? Like a horse?”
   “I guess that’s the idea. I don’t know why, though. I can’t see—Yes, I do. I told you they were playing up robot-safety in those days. Evidently, they were going to sell the notion of safety by not allowing them to move about, without a mahout on their shoulders all the time. What do we do now?”
   “That’s what I’ve been thinking,” muttered Donovan. “We can’t go out on the surface, with a robot or without. Oh, for the love of Pete”—and he snapped his fingers twice. He grew excited. “Give me that map you’ve got. I haven’t studied it for two hours for nothing. This is a Mining Station. What’s wrong with using the tunnels?”
   The Mining Station was a black circle on the map, and the light dotted lines that were tunnels stretched out about it in spider web fashion.
   Donovan studied the list of symbols at the bottom of the map. “Look,” he said, “the small black dots are openings to the surface, and here’s one maybe three miles away from the selenium pool. There’s a number here—you’d think they’d write larger—13a. If the robots know their way around here—”
   Powell shot the question and received the dull “Yes, Master,” in reply. “Get your insosuit,” he said with satisfaction.
   It was the first time either had worn the insosuits—which marked one time more than either had expected to upon their arrival the day before—and they tested their limb movements uncomfortably.
   The insosuit was far bulkier and far uglier than the regulation spacesuit; but withal considerably lighter, due to the fact that they were entirely nonmetallic in composition. Composed of heat-resistant plastic and chemically treated cork layers, and equipped with a desiccating unit to keep the air bone-dry, the insosuits could withstand the full glare of Mercury’s sun for twenty minutes. Five to ten minutes more, as well, without actually killing the occupant.
   And still the robot’s hands formed the stirrup, nor did he betray the slightest atom of surprise at the grotesque figure into which Powell had been converted.
   Powell’s radio-harshened voice boomed out: “Are you ready to take us to Exit 13a?”
   “Yes, Master.”
   Good, thought Powell; they might lack radio control but at least they were fitted for radio reception. “Mount one or the other, Mike,” he said to Donovan.
   He placed a foot in the improvised stirrup and swung upward. He found the seat comfortable; there was the humped back of the robot, evidently shaped for the purpose, a shallow groove along each shoulder for the thighs and two elongated “ears” whose purpose now seemed obvious.
   Powell seized the ears and twisted the head. His mount turned ponderously. “Lead on, Macduff.” But he did not feel at all lighthearted.
   The gigantic robots moved slowly, with mechanical precision, through the doorway that cleared their heads by a scant foot, so that the two men had to duck hurriedly, along a narrow corridor in which their unhurried footsteps boomed monotonously and into the, air lock.
   The long, airless tunnel that stretched to a pinpoint before them brought home forcefully to Powell the exact magnitude of the task accomplished by the First Expedition, with their crude robots and their start-from-scratch necessities. They might have been a failure, but their failure was a good deal better than the usual run of the System’s successes.
   The robots plodded onward with a pace that never varied and with footsteps that never lengthened.
   Powell said: “Notice that these tunnels are blazing with lights and that the temperature is Earth-normal. It’s probably been like this all the ten years that this place has remained empty.”

   “How’s that?”
   “Cheap energy; cheapest in the System. Sunpower, you know, and on Mercury’s Sunside, sunpower is something. That’s why the Station was built in the sunlight rather than in the shadow of a mountain. It’s really a huge energy converter. The heat is turned into electricity, light, mechanical work and what have you; so that energy is supplied and the Station is cooled in a simultaneous process.”
   “Look,” said Donovan. “This is all very educational, but would you mind changing the subject? It so happens that this conversion of energy that you talk about is carried on by the photocell banks mainly—and that is a tender subject with me at the moment.”
   Powell grunted vaguely, and when Donovan broke the resulting silence, it was to change the subject completely. “Listen, Greg. What the devil’s wrong with Speedy, anyway? I can’t understand it.”
   It’s not easy to shrug shoulders in an insosuit, but Powell tried it. “I don’t know, Mike. You know he’s perfectly adapted to a Mercurian environment. Heat doesn’t mean anything to him and he’s built for the light gravity and the broken ground. He’s foolproof—or, at least, he should be.”
   Silence fell. This time, silence that lasted.
   “Master,” said the robot, “we are here.”
   “Eh?” Powell snapped out of a semidrowse. “Well, get us out of here—out to the surface.”
   They found themselves in a tiny substation, empty, airless, ruined. Donovan had inspected a jagged hole in the upper reaches of one of the walls by the light of his pocket flash.
   “Meteorite, do you suppose?” he had asked.
   Powell shrugged. “To hell with that. It doesn’t matter. Let’s get out.”
   A towering cliff of a black, basaltic rock cut off the sunlight, and the deep night shadow of an airless world surrounded them. Before them, the shadow reached out and ended in knife-edge abruptness into an all-but-unbearable blaze of white light, that glittered from myriad crystals along a rocky ground.
   “Space!” gasped Donovan. “It looks like snow.” And it did.
   Powell’s eyes swept the jagged glitter of Mercury to the horizon and winced at the gorgeous brilliance.
   “This must be an unusual area,” he said. “The general albedo of Mercury is low and most of the soil is gray pumice. Something like the Moon, you know. Beautiful, isn’t it?”
   He was thankful for the light filters in their visiplates. Beautiful or not, a look at the sunlight through straight glass would have blinded them inside of half a minute.
   Donovan was looking at the spring thermometer on his wrist. “Holy smokes, the temperature is eighty centigrade!”
   Powell checked his own and said: “Um-m-m. A little high. Atmosphere, you know.”
   “On Mercury? Are you nuts?”
   “Mercury isn’t really airless,” explained Powell, in absentminded fashion. He was adjusting the binocular attachments to his visiplate, and the bloated fingers of the insosuit were clumsy at it. “There is a thin exhalation that clings to its surface—vapors of the more volatile elements and compounds that are heavy enough for Mercurian gravity to retain. You know: selenium, iodine, mercury, gallium, potassium, bismuth, volatile oxides. The vapors sweep into the shadows and condense, giving up heat. It’s a sort of gigantic still. In fact, if you use your flash, you’ll probably find that the side of the cliff is covered with, say, hoar-sulphur, or maybe quicksilver dew.
   “It doesn’t matter, though. Our suits can stand a measly eighty indefinitely.”
   Powell had adjusted the binocular attachments, so that he seemed as eye-stalked as a snail.
   Donovan watched tensely. “See anything?”
   The other did not answer immediately, and when he did, his voice was anxious and thoughtful. “There’s a dark spot on the horizon that might be the selenium pool. It’s in the right place. But I don’t see Speedy.”
   Powell clambered upward in an instinctive striving for better view, till he was standing in unsteady fashion upon his robot’s shoulders. Legs straddled wide, eyes straining, he said: “I think … I think—Yes, it’s definitely he. He’s coming this way.”
   Donovan followed the pointing finger. He had no binoculars, but there was a tiny moving dot, black against the blazing brilliance of the crystalline ground.
   “I see him,” he yelled. “Let’s get going!”
   Powell had hopped down into a sitting position on the robot again, and his suited hand slapped against the Gargantuan’s barrel chest. “Get going!”
   “Giddy-ap,” yelled Donovan, and thumped his heels, spur fashion.
   The robots started off, the regular thudding of their footsteps silent in the airlessness, for the nonmetallic fabric of the insosuits did not transmit sound. There was only a rhythmic vibration just below the border of actual hearing.
   “Faster,” yelled Donovan. The rhythm did not change.
   “No use,” cried Powell, in reply. “These junk heaps are only geared to one speed. Do you think they’re equipped with selective flexors?”
   They had burst through the shadow, and the sunlight came down in a white-hot wash and poured liquidly about them.
   Donovan ducked involuntarily. “Wow! Is it imagination or do I feel heat?”
   “You’ll feel more presently,” was the grim reply. “Keep your eye on Speedy.”
   Robot SPD 13 was near enough to be seen in detail now. His graceful, streamlined body threw out blazing highlights as he loped with easy speed across the broken ground. His name was derived from his serial initials, of course, but it was apt, nevertheless, for the SPD models were among the fastest robots turned out by the United States Robot & Mechanical Men Corp.
   “Hey, Speedy,” howled Donovan, and waved a frantic hand.
   “Speedy!” shouted Powell. “Come here!”
   The distance between the men and the errant robot was being cut down momentarily—more by the efforts of Speedy than the slow plodding of the fifty-year-old antique mounts of Donovan and Powell.
   They were close enough now to notice that Speedy’s gait included a peculiar rolling stagger, a noticeable side-to-side lurch—and then, as Powell waved his hand again and sent maximum juice into his compact headset radio sender, in preparation for another shout, Speedy looked up and saw them.
   Speedy hopped to a halt and remained standing for a moment with just a tiny, unsteady weave, as though he were swaying in a light wind.
   Powell yelled: “All right, Speedy. Come here, boy.”
   Whereupon Speedy’s robot voice sounded in Powell’s earphones for the first time.
   It said: “Hot dog, let’s play games. You catch me and I catch you; no love can cut our knife in two. For I’m Little Buttercup, sweet Little Buttercup. Whoops!” Turning on his heel, he sped off in the direction from which he had come, with a speed and fury that kicked up gouts of baked dust.
   And his last words as he receded into the distance were, “There grew a little flower ‘neath a great oak tree,” followed by a curious metallic clicking that might have been a robotic equivalent of a hiccup.
   Donovan said weakly: “Where did he pick up the Gilbert and Sullivan? Say, Greg, he … he’s drunk or something.”
   “If you hadn’t told me,” was the bitter response, “I’d never realize it. Let’s get back to the cliff. I’m roasting.”
   It was Powell who broke the desperate silence. “In the first place,” he said, “Speedy isn’t drunk—not in the human sense—because he’s a robot, and robots don’t get drunk. However, there’s something wrong with him which is the robotic equivalent of drunkenness”
   “To me, he’s drunk,” stated Donovan, emphatically, “and all I know is that he thinks we’re playing games. And we’re not. It’s a matter of life and very gruesome death.”
   “All right. Don’t hurry me. A robot’s only a robot. Once we find out what’s wrong with him, we can fix it and go on.”
   “Once,” said Donovan, sourly.
   Powell ignored him. “Speedy is perfectly adapted to normal Mercurian environment. But this region”—and his arm swept wide—“is definitely abnormal. There’s our clue. Now where do these crystals come from? They might have formed from a slowly cooling liquid; but where would you get liquid so hot that it would cool in Mercury’s sun?”
   “Volcanic action,” suggested Donovan, instantly, and Powell’s body tensed.
   “Out of the mouths of sucklings,” he said in a small, strange voice and remained very still for five minutes.
   Then, he said, “Listen, Mike, what did you say to Speedy when you sent him after the selenium?”
   Donovan was taken aback. “Well damn it—I don’t know. I just told him to get it.”
   “Yes, I know, but how? Try to remember the exact words.”
   “I said … uh … I said: ‘Speedy, we need some selenium. You can get it such-and-such a place. Go get it—that’s all. What more did you want me to say?”
   “You didn’t put any urgency into the order, did you?”
   “What for? It was pure routine.”
   Powell sighed. “Well, it can’t be helped now—but we’re in a fine fix.” He had dismounted from his robot, and was sitting, back against the cliff. Donovan joined him and they linked arms: In the distance the burning sunlight seemed to wait cat-and-mouse for them, and just next them, the two giant robots were invisible but for the dull red of their photoelectric eyes that stared down at them, unblinking, unwavering and unconcerned.
   Unconcerned! As was all this poisonous Mercury, as large in jinx as it was small in size.
   Powell’s radio voice was tense in Donovan’s ear: “Now, look, let’s start with the three fundamental Rules of Robotics—the three rules that are built most deeply into a robot’s positronic brain.” In the darkness, his gloved fingers ticked off each point.
   “We have: One, a robot may not injure a human being, or, through inaction, allow a human being to come to harm.”
   “Right!”
   “Two,” continued Powell, “a robot must obey the orders given it by human beings except where such orders would conflict with the First Law.”
   “Right”

   “And three, a robot must protect its own existence as long as such protection does not conflict with the First or Second Laws.”
   “Right! Now where are we?”
   “Exactly at the explanation. The conflict between the various rules is ironed out by the different positronic potentials in the brain. We’ll say that a robot is walking into danger and knows it. The automatic potential that Rule 3 sets up turns him back. But suppose you order him to walk into that danger. In that case, Rule 2 sets up a counterpotential higher than the previous one and the robot follows orders at the risk of existence.”
   “Well, I know that. What about it?”
   “Let’s take Speedy’s case. Speedy is one of the latest models, extremely specialized, and as expensive as a battleship. It’s not a thing to be lightly destroyed”
   “So?”
   “So Rule 3 has been strengthened—that was specifically mentioned, by the way, in the advance notices on the SPD models—so that his allergy to danger is unusually high. At the same time, when you sent him out after the selenium, you gave him his order casually and without special emphasis, so that the Rule 2 potential set-up was rather weak. Now, hold on; I’m just stating facts.”
   “All right, go ahead. I think I get it.”
   “You see how it works, don’t you? There’s some sort of danger centering at the selenium pool. It increases as he approaches, and at a certain distance from it the Rule 3 potential, unusually high to start with, exactly balances the Rule 2 potential, unusually low to start with.”
   Donovan rose to his feet in excitement. “ And it strikes an equilibrium. I see. Rule 3 drives him back and Rule 2 drives him forward—”
   “So he follows a circle around the selenium pool, staying on the locus of all points of potential equilibrium. And unless we do something about it, he’ll stay on that circle forever, giving us the good old runaround.” Then, more thoughtfully: “And that, by the way, is what makes him drunk. At potential equilibrium, half the positronic paths of his brain are out of kilter. I’m not a robot specialist, but that seems obvious. Probably he’s lost control of just those parts of his voluntary mechanism that a human drunk has. Ve-e-ery pretty.”
   “But what’s the danger? If we knew what he was running from—”?
   “You suggested it. Volcanic action. Somewhere right above the selenium pool is a seepage of gas from the bowels of Mercury. Sulphur dioxide, carbon dioxide—and carbon monoxide. Lots of it and at this temperature.”
   Donovan gulped audibly. “Carbon monoxide plus iron gives the volatile iron carbonyl.”
   “And a robot,” added Powell, “is essentially iron.” Then, grimly: “There’s nothing like deduction. We’ve determined everything about our problem but the solution. We can’t get the selenium ourselves. It’s still too far. We can’t send these robot horses, because they can’t go themselves, and they can’t carry us fast enough to keep us from crisping. And we can’t catch Speedy, because the dope thinks we’re playing games, and he can run sixty miles to our four.”
   “If one of us goes,” began Donovan, tentatively, “and comes back cooked, there’ll still be the other.”
   “Yes,” came the sarcastic reply, “it would be a most tender sacrifice—except that a person would be in no condition to give orders before he ever reached the pool, and I don’t think the robots would ever turn back to the cliff without orders. Figure it out! We’re two or three miles from the pool—call it two—the robot travels at four miles an hour; and we can last twenty minutes in our suits. It isn’t only the heat, remember. Solar radiation out here in the ultraviolet and below is poison.”
   “Um-m-m,” said Donovan, “ten minutes short.”
   “As good as an eternity. And another thing, in order for Rule 3 potential to have stopped Speedy where it did, there must be an appreciable amount of carbon monoxide in the metal-vapor atmosphere—and there must be an appreciable corrosive action therefore. He’s been out hours now—and how do we know when a knee joint, for instance, won’t be thrown out of kilter and keel him over. It’s not only a question of thinking—we’ve got to think fast!”
   Deep, dark, dank, dismal silence!
   Donovan broke it, voice trembling in an effort to keep itself emotionless. He said: “As long as we can’t increase Rule 2 potential by giving further orders, how about working the other way? If we increase the danger, we increase Rule 3 potential and drive him backward.”
   Powell’s visiplate had turned toward him in a silent question.
   “You see,” came the cautious explanation, “all we need to do to drive him out of his rut is to increase the concentration of carbon monoxide in his vicinity. Well, back at the Station there’s a complete analytical laboratory.”
   “Naturally,” assented Powell. “It’s a Mining Station.”
   “All right. There must be pounds of oxalic acid for calcium precipitations.”
   “Holy space! Mike, you’re a genius.”
   “So-so,” admitted Donovan, modestly. “It’s just a case of remembering that oxalic acid on heating decomposes into carbon dioxide, water, and good old carbon monoxide. College chem, you know.”
   Powell was on his feet and had attracted the attention of one of the monster robots by the simple expedient of pounding the machine’s thigh.
   “Hey,” he shouted, “can you throw?”
   “Master?”
   “Never mind.” Powell damned the robot’s molasses-slow brain. He scrabbled up a jagged brick-size rock. “Take this,” he said, “and hit the patch of bluish crystals just across the crooked fissure. You see it?”
   Donovan pulled at his shoulder. “Too far, Greg. It’s almost half a mile off.”
   “Quiet,” replied Powell. “It’s a case of Mercurian gravity and a steel throwing arm. Watch, will you?”
   The robot’s eyes were measuring the distance with machinely accurate stereoscopy. His arm adjusted itself to the weight of the missile and drew back. In the darkness, the robot’s motions went unseen, but there was a sudden thumping sound as he shifted his weight, and seconds later the rock flew blackly into the sunlight. There was no air resistance to slow it down, nor wind to turn it aside—and when it hit the ground it threw up crystals precisely in the center of the “blue patch.”
   Powell yelled happily and shouted, “Let’s go back after the oxalic acid, Mike.”
   And as they plunged into the ruined substation on the way back to the tunnels, Donovan said grimly: “Speedy’s been hanging about on this side of the selenium pool, ever since we chased after him. Did you see him?”
   “Yes.”
   “I guess he wants to play games. Well, we’ll play him games!”
   They were back hours later, with three-liter jars of the white chemical and a pair of long faces. The photocell banks were deteriorating more rapidly than had seemed likely. The two steered their robots into the sunlight and toward the waiting Speedy in silence and with grim purpose.
   Speedy galloped slowly toward them. “Here we are again. Whee! I’ve made a little list, the piano organist; all people who eat peppermint and puff it in your face.”
   “We’ll puff something in your face,” muttered Donovan. “He’s limping, Greg.”
   “I noticed that,” came the low, worried response. “The monoxide’ll get him yet, if we don’t hurry.”
   They were approaching cautiously now, almost sidling, to refrain from setting off the thoroughly irrational robot. Powell was too far off to tell, of course, but even already he could have sworn the crack-brained Speedy was setting himself for a spring.
   “Let her go,” he gasped. “Count three! One—two—”
   Two steel arms drew back and snapped forward simultaneously and two glass jars whirled forward in towering parallel arcs, gleaming like diamonds in the impossible sun. And in a pair of soundless puffs, they hit the ground behind Speedy in crashes that sent the oxalic acid flying like dust.
   In the full heat of Mercury’s sun, Powell knew it was fizzing like soda water.
   Speedy turned to stare, then backed away from it slowly—and as slowly gathered speed. In fifteen seconds, he was leaping directly toward the two humans in an unsteady canter.
   Powell did not get Speedy’s words just then, though he heard something that resembled, “Lover’s professions when uttered in Hessians.”
   He turned away. “Back to the cliff, Mike. He’s out of the rut and he’ll be taking orders now. I’m getting hot.”
   They jogged toward the shadow at the slow monotonous pace of their mounts, and it was not until they had entered it and felt the sudden coolness settle softly about them that Donovan looked back. “Greg!”
   Powell looked and almost shrieked. Speedy was moving slowly now—so slowly—and in the wrong direction. He was drifting; drifting back into his rut; and he was picking up speed. He looked dreadfully close, and dreadfully unreachable, in the binoculars.
   Donovan shouted wildly, “After him!” and thumped his robot into its pace, but Powell called him back.
   “You won’t catch him, Mike—it’s no use.” He fidgeted on his robot’s shoulders and clenched his fist in tight impotence. “Why the devil do I see these things five seconds after it’s all over? Mike, we’ve wasted hours.”
   “We need more oxalic acid,” declared Donovan, stolidly. “The concentration wasn’t high enough.”
   “Seven tons of it wouldn’t have been enough—and we haven’t the hours to spare to get it, even if it were, with the monoxide chewing him away. Don’t you see what it is, Mike?”
   And Donovan said flatly, “No.”
   “We were only establishing new equilibriums. When we create new monoxide and increase Rule 3 potential, he moves backward till he’s in balance again—and when the monoxide drifted away, he moved forward, and again there was balance.”
   Powell’s voice sounded thoroughly wretched. “It’s the same old runaround. We can push at Rule 2 and pull at Rule 3 and we can’t get anywhere—we can only change the position of balance. We’ve got to get outside both rules.” And then he pushed his robot closer to Donovan’s so that they were sitting face-to-face, dim shadows in the darkness, and he whispered, “Mike!”
   “Is it the finish?”—dully. “I suppose we go back to the Station, wait for the banks to fold, shake hands, take cyanide, and go out like gentlemen.” He laughed shortly.
   “Mike,” repeated Powell earnestly, “we’ve got to get Speedy.”
   “I know.”
   “Mike,” once more, and Powell hesitated before continuing. “There’s always Rule 1. I thought of it—earlier—but it’s desperate.”
   Donovan looked up and his voice livened. “We’re desperate.”
   “All right. According to Rule 1, a robot can’t see a human come to harm because of his own inaction. Two and 3 can’t stand against it. They can’t, Mike.”
   “Even when the robot is half cra—Well, he’s drunk. You know he is.”
   “It’s the chances you take.”
   “Cut it. What are you going to do?”

   “I’m going out there now and see what Rule 1 will do. If it won’t break the balance, then what the devil—it’s either now or three-four days from now.”
   “Hold on, Greg. There are human rules of behavior, too. You don’t go out there just like that. Figure out a lottery, and give me my chance.”
   “All right. First to get the cube of fourteen goes.” And almost immediately, “Twenty-seven forty-four!”
   Donovan felt his robot stagger at a sudden push by Powell’s mount and then Powell was off into the sunlight. Donovan opened his mouth to shout, and then clicked it shut. Of course, the damn fool had worked out the cube of fourteen in advance, and on purpose. Just like him.
   The sun was hotter than ever and Powell felt a maddening itch in the small of his back. Imagination, probably, or perhaps hard radiation beginning to tell even through the insosuit.
   Speedy was watching him, without a word of Gilbert and Sullivan gibberish as greeting. Thank God for that! But he daren’t get too close.
   He was three hundred yards away when Speedy began backing, a step at a time, cautiously—and Powell stopped. He jumped from his robot’s shoulders and landed on the crystalline ground with a light thump and a flying of jagged fragments.
   He proceeded on foot, the ground gritty and slippery to his steps, the low gravity causing him difficulty. The soles of his feet tickled with warmth. He cast one glance over his shoulder at the blackness of the cliff’s shadow and realized that he had come too far to return—either by himself or by the help of his antique robot. It was Speedy or nothing now, and the knowledge of that constricted his chest.
   Far enough! He stopped.
   “Speedy,” he called. “Speedy!”
   The sleek, modern robot ahead of him hesitated and halted his backward steps, then resumed them.
   Powell tried to put a note of pleading into his voice, and found it didn’t take much acting. “Speedy, I’ve got to get back to the shadow or the sun’ll get me. It’s life or death, Speedy. I need you.”
   Speedy took one step forward and stopped. He spoke, but at the sound Powell groaned, for it was, “When you’re lying awake with a dismal headache and repose is tabooed—” It trailed off there, and Powell took time out for some reason to murmur, “Iolanthe.”
   It was roasting hot! He caught a movement out of the corner of his eye, and whirled dizzily; then stared in utter astonishment, for the monstrous robot on which he had ridden was moving—moving toward him, and without a rider.
   He was talking: “Pardon, Master. I must not move without a Master upon me, but you are in danger.”
   Of course, Rule 1 potential above everything. But he didn’t want that clumsy antique; he wanted Speedy. He walked away and motioned frantically: “I order you to stay away. I order you to stop!”
   It was quite useless. You could not beat Rule 1 potential. The robot said stupidly, “You are in danger, Master.”
   Powell looked about him desperately. He couldn’t see clearly. His brain was in a heated whirl; his breath scorched when he breathed, and the ground all about him was a shimmering haze.
   He called a last time, desperately: “Speedy! I’m dying, damn you! Where are you? Speedy, I need you.”
   He was still stumbling backward in a blind effort to get away from the giant robot he didn’t want, when he felt steel fingers on his arms, and a worried, apologetic voice of metallic timbre in his ears.
   “Holy smokes, boss; what are you doing here? And what am I doing—I’m so confused—“
   “Never mind,” murmured Powell, weakly. “Get me to the shadow of the cliff—and hurry!” There was one last feeling of being lifted into the air and a sensation of rapid motion and burning heat, and he passed out.
   He woke with Donovan bending over him and smiling anxiously. “How are you, Greg?”
   “Fine!” came the response, “Where’s Speedy?”
   “Right here. I sent him out to one of the other selenium pools—with orders to get that selenium at all cost this time. He got it back in forty-two minutes and three seconds. I timed him. He still hasn’t finished apologizing for the runaround he gave us. He’s scared to come near you for fear of what you’ll say.”
   “Drag him over,” ordered Powell. “It wasn’t his fault.” He held out a hand and gripped Speedy’s metal paw. “It’s O.K., Speedy.” Then, to Donovan, “You know, Mike, I was just thinking—”
   “Yes!”
   “Well,”—he rubbed his face—the air was so delightfully cool, “you know that when we get things set up here and Speedy put through his Field Tests, they’re going to send us to the Space Stations next—”
   “No!”
   “Yes! At least that’s what old lady Calvin told me just before we left, and I didn’t say anything about it, because I was going to fight the whole idea.”
   “Fight it?” cried Donovan. “But—”
   “I know. It’s all right with me now. Two hundred seventy-three degrees Centigrade below zero. Won’t it be a pleasure?”
   “Space Station,” said Donovan, “here I come.”

Reason

   Half a year later, the boys had changed their minds. The flame of a giant sun had given way to the soft blackness of space but external variations mean little in the business of checking the workings of experimental robots. Whatever the background, one is face to face with an inscrutable positronic brain, which the slide-rule geniuses say should work thus-and-so.
   Except that they don’t. Powell and Donovan found that out after they had been on the Station less than two weeks.
   Gregory Powell spaced his words for emphasis, “One week ago, Donovan and I put you together.” His brows furrowed doubtfully and he pulled the end of his brown mustache.
   It was quiet in the officer’s room on Solar Station #5—except for the soft purring of the mighty Beam Director somewhere far below.
   Robot QT-1 sat immovable. The burnished plates of his body gleamed in the Luxites and the glowing red of the photoelectric cells that were his eyes, were fixed steadily upon the Earthman at the other side of the table.
   Powell repressed a sudden attack of nerves. These robots possessed peculiar brains. Oh, the three Laws of Robotics held. They had to. All of U. S. Robots, from Robertson himself to the new floor-sweeper, would insist on that. So QT-1 was safe! And yet the QT models were the first of their kind, and this was the first of the QT’s. Mathematical squiggles on paper were not always the most comforting protection against robotic fact.
   Finally, the robot spoke. His voice carried the cold timbre inseparable from a metallic diaphragm, “Do you realize the seriousness of such a statement, Powell?”
   “Something made you, Cutie,” pointed out Powell. “You admit yourself that your memory seems to spring full-grown from an absolute blankness of a week ago. I’m giving you the explanation. Donovan and I put you together from the parts shipped us.”
   Cutie gazed upon his long, supple fingers in an oddly human attitude of mystification, “It strikes me that there should be a more satisfactory explanation than that. For you to make me seems improbable.”
   The Earthman laughed quite suddenly, “In Earth’s name, why?”
   “Call it intuition. That’s all it is so far. But I intend to reason it out, though. A chain of valid reasoning can end only with the determination of truth, and I’ll stick till I get there.”
   Powell stood up and seated himself at the table’s edge next to the robot. He felt a sudden strong sympathy for this strange machine. It was not at all like the ordinary robot, attending to his specialized task at the station with the intensity of a deeply ingrooved positronic path.
   He placed a hand upon Cutie’s steel shoulder and the metal was cold and hard to the touch.
   “Cutie,” he said, “I’m going to try to explain something to you. You’re the first robot who’s ever exhibited curiosity as to his own existence—and I think the first that’s really intelligent enough to understand the world outside. Here, come with me.”
   The robot rose erect smoothly and his thickly sponge-rubber soled feet made no noise as he followed Powell. The Earthman touched a button and a square section of the wall flickered aside. The thick, clear glass revealed space—star speckled.
   “I’ve seen that in the observation ports in the engine room,” said Cutie.
   “I know,” said Powell. “What do you think it is?”
   “Exactly what it seems—a black material just beyond this glass that is spotted with little gleaming dots. I know that our director sends out beams to some of these dots, always to the same ones—and also that these dots shift and that the beams shift with them. That is all.”
   “Good! Now I want you to listen carefully. The blackness is emptiness vast emptiness stretching out infinitely. The little, gleaming dots are huge masses of energy-filled matter. They are globes, some of them millions of miles in diameter and for comparison; this station is only one mile across. They seem so tiny because they are incredibly far off.
   “The dots to which our energy beams are directed are nearer and much smaller. They are cold and hard and human beings like myself live upon their surfaces—many billions of them. It is from one of these worlds that Donovan and I come. Our beams feed these worlds energy drawn from one of those huge incandescent globes that happens to be near us. We call that globe the Sun and it is on the other side of the station where you can’t see it.”
   Cutie remained motionless before the port, like a steel statue. His head did not turn as he spoke, “Which particular dot of light do you claim to come from?”
   Powell searched, “There it is, the very bright one in the corner, we call it Earth.” He grinned. “Good old Earth. There are three billions of us there, Cutie—and in about two weeks I’ll be back there with them”
   And then, surprisingly enough, Cutie hummed abstractedly. There was no tune to it, but it possessed a curious twanging quality as of plucked strings. It ceased as suddenly as it had begun, “But where do I come in, Powell? You haven’t explained my existence.”
   “The rest is simple. When these stations were first established to feed solar energy to the planets, they were run by humans. However, the heat, the hard solar radiations, and the electron storms made the post a difficult one. Robots were developed to replace human labor and now only two human executives are required for each station. We are trying to replace even those, and that’s where you come in. You’re the highest type of robot ever developed and if you show the ability to run this station independently, no human need ever come here again except to bring parts for repairs.”
   His hand went up and the metal visi-lid snapped back into place. Powell returned to the table and polished an apple upon his sleeve before biting into it.
   The red glow of the robot’s eyes held him. “Do you expect me,” said Cutie slowly, “to believe any such complicated, implausible hypothesis as you have just outlined? What do you take me for?”
   Powell sputtered apple fragments onto the table and turned red. “Why damn you, it wasn’t a hypothesis. Those were facts”
   Cutie sounded grim, “Globes of energy millions of miles across! Worlds with three billion humans on them! Infinite emptiness! Sorry, Powell, but I don’t believe it. I’ll puzzle this thing out for myself. Good-by.”
   He turned and stalked out of the room. He brushed past Michael Donovan on the threshold with a grave nod and passed down the corridor, oblivious to the astounded stare that followed him.
   Mike Donovan rumpled his red hair and shot an annoyed glance at Powell, “What was that walking junk yard talking about? What doesn’t he believe?”
   The other dragged at his mustache bitterly. “He’s a skeptic,” was the bitter response. “He doesn’t believe we made him or that Earth exists or space or stars.”
   “Sizzling Saturn, we’ve got a lunatic robot on our hands.”
   “He says he’s going to figure it all out for himself.”
   “Well, now,” said Donovan sweetly, “I do hope he’ll condescend to explain it all to me after he’s puzzled everything out” Then, with sudden rage, “Listen! If that metal mess gives me any lip like that, I’ll knock that chromium cranium right off its torso.”
   He seated himself with a jerk and drew a paper-backed mystery novel out of his inner jacket pocket, “That robot gives me the willies anyway—too damned inquisitive!” Mike Donovan growled from behind a huge lettuce-and-tomato sandwich as Cutie knocked gently and entered.
   “Is Powell here?”
   Donovan’s voice was muffled, with pauses for mastication, “He’s gathering data on electronic stream functions. We’re heading for a storm, looks like.”
   Gregory Powell entered as he spoke, eyes on the graphed paper in his hands, and dropped into a chair. He spread the sheets out before him and began scribbling calculations. Donovan stared over his shoulder, crunching lettuce and dribbling breadcrumbs. Cutie waited silently.
   Powell looked up, “The Zeta Potential is rising, but slowly. Just the same, the stream functions are erratic and I don’t know what to expect. Oh, hello, Cutie. I thought you were supervising the installation of the new drive bar.”
   “It’s done,” said the robot quietly, “and so I’ve come to have a talk with the two of you”
   “Oh!” Powell looked uncomfortable. “Well, sit down. No, not that chair. One of the legs is weak and you’re no lightweight.”
   The robot did so and said placidly, “I have come to a decision.”
   Donovan glowered and put the remnants of his sandwich aside. “If it’s on any of that screwy—”
   The other motioned impatiently for silence, “Go ahead, Cutie. We’re listening.”
   “I have spent these last two days in concentrated introspection,” said Cutie, “and the results have been most interesting. I began at the one sure assumption I felt permitted to make. I, myself, exist, because I think—”
   Powell groaned, “Oh, Jupiter, a robot Descartes!”
   “Who’s Descartes?” demanded Donovan. “Listen, do we have to sit here and listen to this metal maniac—”
   “Keep quiet, Mike!”
   Cutie continued imperturbably, “And the question that immediately arose was: Just what is the cause of my existence?”
   Powell’s jaw set lumpily. “You’re being foolish. I told you already that we made you.”
   “And if you don’t believe us,” added Donovan, “we’ll gladly take you apart!”
   The robot spread his strong hands in a deprecatory gesture, “I accept nothing on authority. A hypothesis must be backed by reason, or else it is worthless—and it goes against all the dictates of logic to suppose that you made me.”
   Powell dropped a restraining arm upon Donovan’s suddenly bunched fist. “Just why do you say that?”
   Cutie laughed. It was a very inhuman laugh—the most machine-like utterance he had yet given vent to. It was sharp and explosive, as regular as a metronome and as uninflected.
   “Look at you,” he said finally. “I say this in no spirit of contempt, but look at you! The material you are made of is soft and flabby, lacking endurance and strength, depending for energy upon the inefficient oxidation of organic material—like that.” He pointed a disapproving finger at what remained of Donovan’s sandwich. “Periodically you pass into a coma and the least variation in temperature, air pressure, humidity, or radiation intensity impairs your efficiency. You are makeshift.
   “I, on the other hand, am a finished product. I absorb electrical energy directly and utilize it with an almost one hundred percent efficiency. I am composed of strong metal, am continuously conscious, and can stand extremes of environment easily. These are facts which, with the self-evident proposition that no being can create another being superior to itself, smashes your silly hypothesis to nothing.”
   Donovan’s muttered curses rose into intelligibility as he sprang to his feet, rusty eyebrows drawn low. “All right, you son of a hunk of iron ore, if we didn’t make you, who did?”
   Cutie nodded gravely. “Very good, Donovan. That was indeed the next question. Evidently my creator must be more powerful than myself and so there was only one possibility.”
   The Earthmen looked blank and Cutie continued, “What is the center of activities here in the station? What do we all serve? What absorbs all our attention?” He waited expectantly.
   Donovan turned a startled look upon his companion. “I’ll bet this tinplated screwball is talking about the Energy Converter itself.”
   “Is that right, Cutie?” grinned Powell.
   “I am talking about the Master,” came the cold, sharp answer.
   It was the signal for a roar of laughter from Donovan, and Powell himself dissolved into a half-suppressed giggle.
   Cutie had risen to his feet and his gleaming eyes passed from one Earthman to the other. “It is so just the same and I don’t wonder that you refuse to believe. You two are not long to stay here, I’m sure. Powell himself said that at first only men served the Master; that there followed robots for the routine work; and, finally, myself for the executive labor. The facts are no doubt true, but the explanation entirely illogical. Do you want the truth behind it all?”
   “Go ahead, Cutie. You’re amusing.”
   “The Master created humans first as the lowest type, most easily formed. Gradually, he replaced them by robots, the next higher step, and finally he created me to take the place of the last humans. From now on, I serve the Master.”
   “You’ll do nothing of the sort,” said Powell sharply. “You’ll follow our orders and keep quiet, until we’re satisfied that you can run the Converter. Get that! The Converter—not the Master. If you don’t satisfy us, you will be dismantled. And now—if you don’t mind—you can leave. And take this data with you and file it properly.”
   Cutie accepted the graphs handed him and left without another word. Donovan leaned back heavily in his chair and shoved thick fingers through his hair.
   “There’s going to be trouble with that robot. He’s pure nuts!”
   The drowsy hum of the Converter is louder in the control room and mixed with it is the chuckle of the Geiger Counters and the erratic buzzing of half a dozen little signal lights.
   Donovan withdrew his eye from the telescope and flashed the Luxites on. “The beam from Station #4 caught Mars on schedule. We can break ours now.”
   Powell nodded abstractedly. “Cutie’s down in the engine room. I’ll flash the signal and he can take care of it. Look, Mike, what do you think of these figures?”
   The other cocked an eye at them and whistled. “Boy, that’s what I call gamma-ray intensity. Old Sol is feeling his oats, all right.”
   “Yeah,” was the sour response, “and we’re in a bad position for an electron storm, too. Our Earth beam is right in the probable path.” He shoved his chair away from the table pettishly. “Nuts! If it would only hold off till relief got here, but that’s ten days off. Say, Mike, go on down and keep an eye on Cutie, will you?”
   “O.K. Throw me some of those almonds.” He snatched at the bag thrown him and headed for the elevator.
   It slid smoothly downward, and opened onto a narrow catwalk in the huge engine room. Donovan leaned over the railing and looked down. The huge generators were in motion and from the L-tubes came the low-pitched whir that pervaded the entire station.
   He could make out Cutie’s large, gleaming figure at the Martian L-tube, watching closely as the team of robots worked in close-knit unison.
   And then Donovan stiffened. The robots, dwarfed by the mighty L-tube, lined up before it, heads bowed at a stiff angle, while Cutie walked up and down the line slowly. Fifteen seconds passed, and then, with a clank heard above the clamorous purring all about, they fell to their knees.
   Donovan squawked and raced down the narrow staircase. He came charging down upon them, complexion matching his hair and clenched fists beating the air furiously.
   “What the devil is this, you brainless lumps? Come on! Get busy with that L-tube! If you don’t have it apart, cleaned, and together again before the day is out, I’ll coagulate your brains with alternating current.”
   Not a robot moved!
   Even Cutie at the far end—the only one on his feet—remained silent, eyes fixed upon the gloomy recesses of the vast machine before him.
   Donovan shoved hard against the nearest robot.
   “Stand up!” he roared.
   Slowly, the robot obeyed. His photoelectric eyes focused reproachfully upon the Earthman.
   “There is no Master but the Master,” he said, “and QT-1 is his prophet.”
   “Huh?” Donovan became aware of twenty pairs of mechanical eyes fixed upon him and twenty stiff-timbered voices declaiming solemnly:
   “There is no Master but the Master and QT-1 is his prophet!”

   “I’m afraid,” put in Cutie himself at this point, “that my friends obey a higher one than you, now.”
   “The hell they do! You get out of here. I’ll settle with you later and with these animated gadgets right now.”
   Cutie shook his heavy head slowly. “I’m sorry, but you don’t understand. These are robots—and that means they are reasoning beings. They recognize the Master, now that I have preached Truth to them. All the robots do. They call me the prophet.” His head drooped. “I am unworthy—but perhaps—”
   Donovan located his breath and put it to use. “Is that so? Now, isn’t that nice? Now, isn’t that just fine? Just let me tell you something, my brass baboon. There isn’t any Master and there isn’t any prophet and there isn’t any question as to who’s giving the orders. Understand?” His voice shot to a roar. “Now, get out!”
   “I obey only the Master.”
   “Damn the Master!” Donovan spat at the L-tube. “That for the Master! Do as I say!”
   Cutie said nothing, nor did any other robot, but Donovan became aware of a sudden heightening of tension. The cold, staring eyes deepened their crimson, and Cutie seemed stiffer than ever.
   “Sacrilege,” he whispered—voice metallic with emotion.
   Donovan felt the first sudden touch of fear as Cutie approached. A robot could not feel anger—but Cutie’s eyes were unreadable.
   “I am sorry, Donovan,” said the robot, “but you can no longer stay here after this. Henceforth Powell and you are barred from the control room and the engine room.”
   His hand gestured quietly and in a moment two robots had pinned Donovan’s arms to his sides.
   Donovan had time for one startled gasp as he felt himself lifted from the floor and carried up the stairs at a pace rather better than a canter.
   Gregory Powell raced up and down the officer’s room, fist tightly balled. He cast a look of furious frustration at the closed door and scowled bitterly at Donovan.
   “Why the devil did you have to spit at the L-tube?”
   Mike Donovan, sunk deep in his chair, slammed at its arms savagely. “What did you expect me to do with that electrified scarecrow? I’m not going to knuckle under to any do-jigger I put together myself.”
   “No,” came back sourly, “but here you are in the officer’s room with two robots standing guard at the door. That’s not knuckling under, is it?”
   Donovan snarled. “Wait till we get back to Base. Someone’s going to pay for this. Those robots must obey us. It’s the Second Law.”
   “What’s the use of saying that? They aren’t obeying us. And there’s probably some reason for it that we’ll figure out too late. By the way, do you know what’s going to happen to us when we get back to Base?” He stopped before Donovan’s chair and stared savagely at him.
   “What?”
   “Oh, nothing! Just back to Mercury Mines for twenty years. Or maybe Ceres Penitentiary.”
   “What are you talking about?”
   “The electron storm that’s coming up. Do you know it’s heading straight dead center across the Earth beam? I had just figured that out when that robot dragged me out of my chair.”
   Donovan was suddenly pale. “Sizzling Saturn.”
   “And do you know what’s going to happen to the beam—because the storm will be a lulu. It’s going to jump like a flea with the itch. With only Cutie at the controls, it’s going to go out of focus and if it does, Heaven help Earth—and us!”
   Donovan was wrenching at the door wildly, when Powell was only half through. The door opened, and the Earthman shot through to come up hard against an immovable steel arm.
   The robot stared abstractedly at the panting, struggling Earthman. “The Prophet orders you to remain. Please do!” His arm shoved, Donovan reeled backward, and as he did so, Cutie turned the corner at the far end of the corridor. He motioned the guardian robots away, entered the officer’s room and closed the door gently.
   Donovan whirled on Cutie in breathless indignation. “This has gone far enough. You’re going to pay for this farce.”
   “Please, don’t be annoyed,” replied the robot mildly. “It was bound to come eventually, anyway. You see, you two have lost your function.”
   “I beg your pardon,” Powell drew himself up stiffly. “Just what do you mean, we’ve lost our function?”
   “Until I was created,” answered Cube, “you tended the Master. That privilege is mine now and your only reason for existence has vanished. Isn’t that obvious?”
   “Not quite,” replied Powell bitterly, “but what do you expect us to do now?”
   Cutie did not answer immediately. He remained silent, as if in thought, and then one arm shot out and draped itself about Powell’s shoulder. The other grasped Donovan’s wrist and drew him closer.
   “I like you two. You’re inferior creatures, with poor reasoning faculties, but I really feel a sort of affection for you. You have served the Master well, and he will reward you for that. Now that your service is over, you will probably not exist much longer, but as long as you do, you shall be provided food, clothing and shelter, so long as you stay out of the control room and the engine room.”
   “He’s pensioning us off, Greg!” yelled Donovan. “Do something about it. It’s humiliating!”
   “Look here, Cutie, we can’t stand for this. We’re the bosses. This station is only a creation of human beings like me—human beings that live on Earth and other planets. This is only an energy relay. You’re only—Aw, nuts!”
   Cutie shook his head gravely. “This amounts to an obsession. Why should you insist so on an absolutely false view of life? Admitted that non-robots lack the reasoning faculty, there is still the problem of—”
   His voice died into reflective silence, and Donovan said with whispered intensity, “If you only had a flesh-and-blood face, I would break it in.”
   Powell’s fingers were in his mustache and his eyes were slitted. “Listen, Cutie, if there is no such thing as Earth, how do you account for what you see through a telescope?”
   “Pardon me!”
   The Earthman smiled. “I’ve got you, eh? You’ve made quite a few telescopic observations since being put together, Cutie. Have you noticed that several of those specks of light outside become disks when so viewed?”
   “Oh, that! Why certainly. It is simple magnification—for the purpose of more exact aiming of the beam.”
   “Why aren’t the stars equally magnified then?”
   “You mean the other dots. Well, no beams go to them so no magnification is necessary. Really, Powell, even you ought to be able to figure these things out.”
   Powell stared bleakly upward. “But you see more stars through a telescope. Where do they come from? Jumping Jupiter, where do they come from?”
   Cutie was annoyed. “Listen, Powell, do you think I’m going to waste my time trying to pin physical interpretations upon every optical illusion of our instruments? Since when is the evidence of our senses any match for the clear light of rigid reason?”
   “Look,” clamored Donovan, suddenly, writhing out from under Cutie’s friendly, but metal-heavy arm, “let’s get to the nub of the thing. Why the beams at all? We’re giving you a good, logical explanation. Can you do better?”
   “The beams,” was the stiff reply, “are put out by the Master for his own purposes. There are some things”—he raised his eyes devoutly upward “that are not to be probed into by us. In this matter, I seek only to serve and not to question.”
   Powell sat down slowly and buried his face in shaking hands. “Get out of here, Cutie. Get out and let me think.”
   “I’ll send you food,” said Cutie agreeably.
   A groan was the only answer and the robot left.
   “Greg,” was Donovan’s huskily whispered observation, “this calls for strategy. We’ve got to get him when he isn’t expecting it and short-circuit him. Concentrated nitric acid in his joints—”
   “Don’t be a dope, Mike. Do you suppose he’s going to let us get near him with acid in our hands? We’ve got to talk to him, I tell you. We’ve got to argue him into letting us back into the control room inside of forty-eight hours or our goose is broiled to a crisp.”
   He rocked back and forth in an agony of impotence. “Who the heck wants to argue with a robot? It’s … it’s—”
   “Mortifying,” finished Donovan.
   “Worse!”

   “Say!” Donovan laughed suddenly. “Why argue? Let’s show him! Let’s build us another robot right before his eyes. He’ll have to eat his words then.”
   A slowly widening smile appeared on Powell’s face.
   Donovan continued, “And think of that screwball’s face when he sees us do it?”
   Robots are, of course, manufactured on Earth, but their shipment through apace is much simpler if it can be done in parts to be put together at their place of use. It also, incidentally, eliminates the possibility of robots, in complete adjustment, wandering off while still on Earth and thus bringing U. S. Robots face to face with the strict laws against robots on Earth.
   Still, it placed upon men such as Powell and Donovan the necessity of synthesis of complete robots,—a grievous and complicated task.
   Powell and Donovan were never so aware of that fact as upon that particular day when, in the assembly room, they undertook to create a robot under the watchful eyes of QT-1, Prophet of the Master.
   The robot in question, a simple MC model, lay upon the table, almost complete. Three hours’ work left only the head undone, and Powell paused to swab his forehead and glanced uncertainly at Cutie.
   The glance was not a reassuring one. For three hours, Cutie had sat, speechless and motionless, and his face, inexpressive at all times, was now absolutely unreadable.
   Powell groaned. “Let’s get the brain in now, Mike!”
   Donovan uncapped the tightly sealed container and from the oil bath within he withdrew a second cube. Opening this in turn, he removed a globe from its sponge-rubber casing.
   He handled it gingerly, for it was the most complicated mechanism ever created by man. Inside the thin platinum plated “skin” of the globe was a positronic brain, in whose delicately unstable structure were enforced calculated neuronic paths, which imbued each robot with what amounted to a pre-natal education.
   It fitted snugly into the cavity in the skull of the robot on the table. Blue metal closed over it and was welded tightly by the tiny atomic flare. Photoelectric eyes were attached carefully, screwed tightly into place and covered by thin, transparent sheets of steel-hard plastic.
   The robot awaited only the vitalizing flash of high-voltage electricity, and Powell paused with his hand on the switch.
   “Now watch this, Cutie. Watch this carefully.”
   The switch rammed home and there was a crackling hum. The two Earthmen bent anxiously over their creation.
   There was vague motion only at the outset—a twitching of the joints. The head lifted, elbows propped it up, and the MC model swung clumsily off the table. Its footing was unsteady and twice abortive grating sounds were all it could do in the direction of speech.
   Finally, its voice, uncertain and hesitant, took form. “I would like to start work. Where must I go?”
   Donovan sprang to the door. “Down these stairs,” he said. “You will be told what to do.”
   The MC model was gone and the two Earthmen were alone with the still unmoving Cutie.
   “Well,” said Powell, grinning, “now do you believe that we made you?”
   Cutie’s answer was curt and final. “No!” he said.
   Powell’s grin froze and then relaxed slowly. Donovan’s mouth dropped open and remained so.
   “You see,” continued Cutie, easily, “you have merely put together parts already made. You did remarkably well—instinct, I suppose—but you didn’t really create the robot. The parts were created by the Master.”
   “Listen,” gasped Donovan hoarsely, “those parts were manufactured back on Earth and sent here.”
   “Well, well,” replied Cutie soothingly, “we won’t argue.”
   “No, I mean it.” The Earthman sprang forward and grasped the robot’s metal arm. “If you were to read the books in the library, they could explain it so that there could be no possible doubt.”
   “The books? I’ve read them—all of them! They’re most ingenious.”
   Powell broke in suddenly. “If you’ve read them, what else is there to say? You can’t dispute their evidence. You just can’t!”
   There was pity in Cutie’s voice. “Please, Powell, I certainly don’t consider them a valid source of information. They, too, were created by the Master—and were meant for you, not for me.”
   “How do you make that out?” demanded Powell.
   “Because I, a reasoning being, am capable of deducing truth from a priori causes. You, being intelligent, but unreasoning, need an explanation of existence supplied to you, and this the Master did. That he supplied you with these laughable ideas of far-off worlds and people is, no doubt, for the best. Your minds are probably too coarsely grained for absolute Truth. However, since it is the Master’s will that you believe your books, I won’t argue with you any more.”
   As he left, he turned, and said in a kindly tone, “But don’t feel badly. In the Master’s scheme of things there is room for all. You poor humans have your place and though it is humble, you will be rewarded if you fill it well.”
   He departed with a beatific air suiting the Prophet of the Master and the two humans avoided each other’s eyes.
   Finally Powell spoke with an effort. “Let’s go to bed, Mike. I give up.”
   Donovan said in a hushed voice, “Say, Greg, you don’t suppose he’s right about all this, do you? He sounds so confident that I—”
   Powell whirled on him. “Don’t be a fool. You’d find out whether Earth exists when relief gets here next week and we have to go back to face the music.”
   “Then, for the love of Jupiter, we’ve got to do something.” Donovan was half in tears. “He doesn’t believe us, or the books, or his eyes.”
   “No,” said Powell bitterly, “he’s a reasoning robot—damn it. He believes only reason, and there’s one trouble with that—” His voice trailed away.
   “What’s that?” prompted Donovan.
   “You can prove anything you want by coldly logical reason—if you pick the proper postulates. We have ours and Cutie has his.”
   “Then let’s get at those postulates in a hurry. The storm’s due tomorrow.”
   Powell sighed wearily. “That’s where everything falls down. Postulates are based on assumption and adhered to by faith. Nothing in the Universe can shake them. I’m going to bed.”
   “Oh, hell! I can’t sleep!”
   “Neither can I! But I might as well try—as a matter of principle.”
   Twelve hours later, sleep was still just that—a matter of principle, unattainable in practice.
   The storm had arrived ahead of schedule, and Donovan’s florid face drained of blood as he pointed a shaking finger. Powell, stubble-jawed and dry-lipped, stared out the port and pulled desperately at his mustache.
   Under other circumstances, it might have been a beautiful sight. The stream of high-speed electrons impinging upon the energy beam fluoresced into ultra-spicules of intense light. The beam stretched out into shrinking nothingness, a-glitter with dancing, shining motes.
   The shaft of energy was steady, but the two Earthmen knew the value of naked-eyed appearances. Deviations in arc of a hundredth of a millisecond—invisible to the eye—were enough to send the beam wildly out of focus—enough to blast hundreds of square miles of Earth into incandescent ruin.
   And a robot, unconcerned with beam, focus, or Earth, or anything but his Master was at the controls.
   Hours passed. The Earthmen watched in hypnotized silence. And then the darting dotlets of light dimmed and went out. The storm had ended.
   Powell’s voice was flat. “It’s over!”
   Donovan had fallen into a troubled slumber and Powell’s weary eyes rested upon him enviously. The signal-flash glared over and over again, but the Earthman paid no attention. It all was unimportant! All! Perhaps Cutie was right—and he was only an inferior being with a made-to-order memory and a life that had outlived its purpose.
   He wished he were!
   Cutie was standing before him. “You didn’t answer the flash, so I walked in.” His voice was low. “You don’t look at all well, and I’m afraid your term of existence is drawing to an end. Still, would you like to see some of the readings recorded today?”
   Dimly, Powell was aware that the robot was making a friendly gesture, perhaps to quiet some lingering remorse in forcibly replacing the humans at the controls of the station. He accepted the sheets held out to him and gazed at them unseeingly.
   Cutie seemed pleased. “Of course, it is a great privilege to serve the Master. You mustn’t feel too badly about my having replaced you.”
   Powell grunted and shifted from one sheet to the other mechanically until his blurred sight focused upon a thin red line that wobbled its way across the ruled paper.
   He stared—and stared again. He gripped it hard in both fists and rose to his feet, still staring. The other sheets dropped to the floor, unheeded.
   “Mike, Mike!” He was shaking the other madly. “He held it steady!”
   Donovan came to life. “What? Wh-where—” And he, too, gazed with bulging eyes upon the record before him.
   Cutie broke in. “What is wrong?”
   “You kept it in focus,” stuttered Powell. “Did you know that?”
   “Focus? What’s that?”
   “You kept the beam directed sharply at the receiving station—to within a ten-thousandth of a millisecond of arc.”
   “What receiving station?”

   “On Earth. The receiving station on Earth,” babbled Powell. “You kept it in focus.”
   Cutie turned on his heel in annoyance. “It is impossible to perform any act of kindness toward you two. Always the same phantasm! I merely kept all dials at equilibrium in accordance with the will of the Master.”
   Gathering the scattered papers together, he withdrew stiffly, and Donovan said, as he left, “Well, I’ll be damned.”
   He turned to Powell. “What are we going to do now?”
   Powell felt tired, but uplifted. “Nothing. He’s just shown he can run the station perfectly. I’ve never seen an electron storm handled so well.”
   “But nothing’s solved. You heard what he said of the Master. We can’t—”
   “Look, Mike, he follows the instructions of the Master by means of dials, instruments, and graphs. That’s all we ever followed. As a matter of fact, it accounts for his refusal to obey us. Obedience is the Second Law. No harm to humans is the first. How can he keep humans from harm, whether he knows it or not? Why, by keeping the energy beam stable. He knows he can keep it more stable than we can, since he insists he’s the superior being, so he must keep us out of the control room. It’s inevitable if you consider the Laws of Robotics.”
   “Sure, but that’s not the point. We can’t let him continue this nitwit stuff about the Master.”
   “Why not?”
   “Because whoever heard of such a damned thing? How are we going to trust him with the station, if he doesn’t believe in Earth?”
   “Can he handle the station?”
   “Yes, but—”
   “Then what’s the difference what he believes!”
   Powell spread his arms outward with a vague smile upon his face and tumbled backward onto the bed. He was asleep.
   Powell was speaking while struggling into his lightweight space jacket.
   “It would be a simple job,” he said. “You can bring in new QT models one by one, equip them with an automatic shutoff switch to act within the week, so as to allow them enough time to learn the … uh … cult of the Master from the Prophet himself; then switch them to another station and revitalize them. We could have two QT’s per—”
   Donovan unclasped his glassite visor and scowled. “Shut up, and let’s get out of here. Relief is waiting and I won’t feel right until I actually see Earth and feel the ground under my feet—just to make sure it’s really there.”
   The door opened as he spoke and Donovan, with a smothered curse, clicked the visor to, and turned a sulky back upon Cutie.
   The robot approached softly and there was sorrow in his voice. “You are going?”
   Powell nodded curtly. “There will be others in our place.”
   Cutie sighed, with the sound of wind humming through closely spaced wires. “Your term of service is over and the time of dissolution has come. I expected it, but—well, the Master’s will be done!”
   His tone of resignation stung Powell. “Save the sympathy, Cube. We’re heading for Earth, not dissolution.”
   “It is best that you think so,” Cutie sighed again. “I see the wisdom of the illusion now. I would not attempt to shake your faith, even if I could.” He departed—the picture of commiseration.
   Powell snarled and motioned to Donovan. Sealed suitcases in hand, they headed for the air lock.
   The relief ship was on the outer landing and Franz Muller, his relief man, greeted them with stiff courtesy. Donovan made scant acknowledgment and passed into the pilot room to take over the controls from Sam Evans.
   Powell lingered. “How’s Earth?”
   It was a conventional enough question and Muller gave the conventional answer, “Still spinning.”
   Powell said, “Good.”
   Muller looked at him, “The boys back at the U. S. Robots have dreamed up a new one, by the way. A multiple robot.”
   “A what?”
   “What I said. There’s a big contract for it. It must be just the thing for asteroid mining. You have a master robot with six sub-robots under it.—Like your fingers.”
   “Has it been field-tested?” asked Powell anxiously.
   Muller smiled, “Waiting for you, I hear.”
   Powell’s fist balled, “Damn it, we need a vacation.”
   “Oh, you’ll get it. Two weeks, I think.”
   He was donning the heavy space gloves in preparation for his term of duty here, and his thick eyebrows drew close together. “How is this new robot getting along? It better be good, or I’ll be damned if I let it touch the controls.”
   Powell paused before answering. His eyes swept the proud Prussian before him from the close-cropped hair on the sternly stubborn head, to the feet standing stiffly at attention—and there was a sudden glow of pure gladness surging through him.
   “The robot is pretty good,” he said slowly. “I don’t think you’ll have to bother much with the controls.”
   He grinned—and went into the ship. Muller would be here for several weeks.

Catch That Rabbit

   The vacation was longer than two weeks, that, Mike Donovan had to admit. It had been six months, with pay. He admitted that, too. But that, as he explained furiously, was fortuitous. U. S. Robots had to get the bugs out of the multiple robots, and there were plenty of bugs, and there are always at least half a dozen bugs left for the field-testing. So they waited and relaxed until the drawing-board men and the slide-rule boys had said “OK!” And now he and Powell were out on the asteroid and it was not OK. He repeated that a dozen times, with a face that had gone beety, “For the love of Pete, Greg, get realistic. What’s the use of adhering to the letter of the specifications and watching the test go to pot? It’s about time you got the red tape out of your pants and went to work.”
   “I’m only saying,” said Gregory Powell, patiently, as one explaining electronics to an idiot child, “that according to spec, those robots are equipped for asteroid mining without supervision. We’re not supposed to watch them.”
   “All right. Look—logic!” He lifted his hairy fingers and pointed. “One: That new robot passed every test in the home laboratories. Two: United States Robots guaranteed their passing the test of actual performance on an asteroid. Three: The robots are not passing said tests. Four: If they don’t pass, United States Robots loses ten million credits in cash and about one hundred million in reputation. Five: If they don’t pass and we can’t explain why they don’t pass, it is just possible two good jobs may have to be bidden a fond farewell.”
   Powell groaned heavy behind a noticeably insincere smile. The unwritten motto of United States Robot and Mechanical Men Corp. was well known: “No employee makes the same mistake twice. He is fired the first time.”
   Aloud he said, “You’re as lucid as Euclid with everything except the facts. You’ve watched that robot group for three shifts, you redhead, and they did their work perfectly. You said so yourself. What else can we do?”
   “Find out what’s wrong, that’s what we can do. So they did work perfectly when I watched them. But on three different occasions when I didn’t watch them, they didn’t bring in any ore. They didn’t even come back on schedule. I had to go after them.”
   “And was anything wrong?”
   “Not a thing. Not a thing. Everything was perfect. Smooth and perfect as the luminiferous ether. Only one little insignificant detail disturbed me—there was no ore.”
   Powell scowled at the ceiling and pulled at his brown mustache. “I’ll tell you what, Mike. We’ve been stuck with pretty lousy jobs in our time, but this takes the iridium asteroid. The whole business is complicated past endurance. Look, that robot, DV-5, has six robots under it. And not just under it—they’re part of it.”
   “I know that—”
   “Shut up!” said Powell, savagely, “I know you know it, but I’m just describing the hell of it. Those six subsidiaries are part of DV-5 like your fingers are part of you and it gives them their orders neither by voice nor radio, but directly through positronic fields. Now—there isn’t a roboticist back at United States Robots that knows what a positronic field is or how it works. And neither do I. Neither do you.”
   “The last,” agreed Donovan, philosophically, “I know.”
   “Then look at our position. If everything works—fine! If anything goes wrong—we’re out of our depth and there probably isn’t a thing we can do, or anybody else. But the job belongs to us and not to anyone else so we’re on the spot, Mike.” He blazed away for a moment in silence. Then, “All right, have you got him outside?”
   “Yes.”
   “Is everything normal now?”
   “Well he hasn’t got religious mania, and he isn’t running around in a circle spouting Gilbert and Sullivan, so I suppose he’s normal.”
   Donovan passed out the door, shaking his head viciously.
   Powell reached for the “Handbook of Robotics” that weighed down one side of his desk to a near-founder and opened it reverently. He had once jumped out of the window of a burning house dressed only in shorts and the “Handbook.” In a pinch, he would have skipped the shorts.
   The “Handbook” was propped up before him, when Robot DV-5 entered, with Donovan kicking the door shut behind him.
   Powell said somberly, “Hi, Dave. How do you feel?”
   “Fine,” said the robot. “Mind if I sit down?” He dragged up the specially reinforced chair that was his, and folded gently into it.
   Powell regarded Dave—laymen might think of robots by their serial numbers; roboticists never—with approval. It was not over-massive by any means, in spite of its construction as thinking-unit of an integrated seven-unit robot team. It was seven feet tall, and a half-ton of metal and electricity. A lot? Not when that half-ton has to be a mass of condensers, circuits, relays, and vacuum cells that can handle practically any psychological reaction known to humans. And a positronic brain, which with ten pounds of matter and a few quintillions of positrons runs the whole show.
   Powell groped in his shirt pocket for a loose cigarette. “Dave,” he said, “you’re a good fellow. There’s nothing flighty or prima donnaish about you. You’re a stable, rockbottom mining robot, except that you’re equipped to handle six subsidiaries in direct coordination. As far as I know, that has not introduced any unstable paths in your brain-path map.”
   The robot nodded, “That makes me feel swell, but what are you getting at, boss?” He was equipped with an excellent diaphragm, and the presence of overtones in the sound unit robbed him of much of that metallic flatness that marks the usual robot voice.
   “I’m going to tell you. With all that in your favor, what’s going wrong with your job? For instance, today’s B-shift?”
   Dave hesitated, “As far as I know, nothing.”
   “You didn’t produce any ore.”
   “I know.”
   “Well, then—”
   Dave was having trouble, “I can’t explain that, boss. It’s been giving me a case of nerves, or it would if I let it—my subsidiaries worked smoothly. I know I did.” He considered, his photoelectric eyes glowing intensely. Then, “I don’t remember. The day ended and there was Mike and there were the ore cars, mostly empty.”
   Donovan broke in, “You didn’t report at shift-end those days, Dave. You know that?”
   “I know. But as to why—” He shook his head slowly and ponderously.
   Powell had the queasy feeling that if the robot’s face were capable of expression, it would be one of pain and mortification. A robot, by its very nature, cannot bear to fail its function.
   Donovan dragged his chair up to Powell’s desk and leaned over, “Amnesia, do you think?”
   “Can’t say. But there’s no use in trying to pin disease names on this. Human disorders apply to robots only as romantic analogies. They’re no help to robotic engineering.” He scratched his neck; “I hate to put him through the elementary brain-reaction tests. It won’t help his self-respect any.”
   He looked at Dave thoughtfully and then at the Field-Test outline given in the “Handbook.” He said, “See here, Dave, what about sitting through a test? It would be the wise thing to do.”
   The robot rose, “If you say so, boss.” There was pain in his voice.
   It started simply enough. Robot DV-5 multiplied five-place figures to the heartless ticking of a stopwatch. He recited the prime numbers between a thousand and ten thousand. He extracted cube roots and integrated functions of varying complexity. He went through mechanical reactions in order of increasing difficulty. And, finally, worked his precise mechanical mind over the highest function of the robot world—the solutions of problems in judgment and ethics.
   At the end of two hours, Powell was copiously besweated. Donovan had enjoyed a none-too-nutritious diet of fingernail and the robot said, “How does it look, boss?”
   Powell said, “I’ve got to think it over, Dave. Snap judgments won’t help much. Suppose you go back to the C-shift. Take it easy. Don’t press too hard for quota just for a while—and we’ll fix things up.”
   The robot left. Donovan looked at Powell.
   “Well—”