Transcriber's Note: This etext was produced from Analog Science Fact & Fiction August 1961. Extensive research did not uncover any evidence that the U. S. Copyright on this publication was renewed. HANGING BY A THREAD By DAVID GORDON _It's seldom that the fate of a shipful of men literally hangs by a thread--but it's also seldom that a device, every part of which has been thoroughly tested, won't work. . . . _ Illustrated by Douglas * * * * * Jayjay Kelvin was sitting in the lounge of the interplanetary cargovessel _Persephone_, his feet propped up on the low table in front ofthe couch, and his attention focused almost totally on the small bookhe was reading. The lounge itself was cozily small; the _Persephone_had not been designed as a passenger vessel, and the two passengersshe was carrying at the time had been taken on as an accommodationrather than as a money-making proposition. On the other hand, the_Persephone_ and other ships like her were the only method of gettingto where Jayjay Kelvin wanted to go; there were no regular passengerruns to Pluto. It's hardly the vacation spot of the Solar System. On the other side of the table, Jeffry Hull was working industriouslywith pencil and paper. Jayjay kept his nose buried in his book--notbecause he was deliberately slighting Hull, but because he wasgenuinely interested in the book. _"Now wait, " said Masterson, looking thoughtfully at the footprints onthe floor of the cabin where Jed Hooker had died. "Jest take anotherlook at these prints, Charlie. Silver Bill Greer couldn't have gotmuch more than his big toe into boots that small! Somethin' tells methe Pecos Kid has. . . . "_ ". . . Traveled nearly two billion miles since then, " said Hull. Jayjay lifted his head from his book. "What?" He blinked. "I'm sorry;I wasn't listening. What did you say?" The younger man was still grinning triumphantly. "I said: We areapproaching turnover, and, according to my figures, nine days ofacceleration at one standard gee will give us a velocity of seventeenmillion, five hundred and fifty miles per hour, and we have covered adistance of nearly two billion miles. " Then he added: "That is, if Iremembered my formulas correctly. " Jayjay Kelvin looked thoughtfully at the ceiling while he ran throughthe figures in his head. "Something like that. It's the right order ofmagnitude, anyway. " Hull looked a little miffed. "What answer did you get?" "A little less than eight times ten to the third kilometers persecond. I was just figuring roughly. " Hull scribbled hastily, then smiled again. "Eighteen million miles anhour, that would be. My memory's better than I thought at first. I'mglad I didn't have to figure the time; doing square roots is a processI've forgotten. " That was understandable, Jayjay thought. Hull was working for hisdoctorate in sociology, and there certainly wasn't much necessity fora sociologist to remember his freshman physics, much less hishigh-school math. Still, it was somewhat of a relief to find that Hull was interested insomething besides the "sociological reactions of Man in space". Theboy had spent six months in the mining cities in the Asteroid Belt, and another six investigating the Jovian chemical synthesis planes andtheir attendant cities. Now he was heading out to spend a few moremonths observing the "sociological organization Gestalt" of the menand women who worked at the toughest job in the System--taking theheavy metals from the particularly dense sphere of Pluto. Hull began scribbling on his paper again, evidently lost in the joysof elementary physics, so Jayjay Kelvin went back to his book. He had just read three words when Hull said: "Mr. Kelvin, do you mindif I ask a question?" Jayjay looked up from his book and saw that Jeffry Hull had revertedto his role of the earnest young sociologist. Ah, well. "As I've toldyou before, Mr. Hull, questions do not offend me, but I can'tguarantee that the answers won't offend you. " "Yes; of course, " Hull said in his best investigatory manner. "Iappreciate that. It's just that . . . Well, I have trained myself tonotice small things. The little details that are sometimes soimportant in sociological investigations. Not, you understand, as anattempt to pry into the private life of the individual, but to roundout the overall picture. " Jayjay nodded politely. To his quixotic and pixie-like mind, the term_overall picture_ conjured up the vision of a large and carefullydetailed painting of a pair of dirty overalls, but he kept the smileoff his face and merely said: "I understand. " "Well, I've noticed that you're quite an avid reader. That isn'tunusual in a successful businessman, of course; one doesn't become asuccessful businessman unless one has a thirst for knowledge. " "Hm-m-m, " said Jayjay. "But, " Hull continued earnestly, "I noticed that you've read most ofthe . . . Uh . . . Historical romances in the library. . . . " "You mean Westerns, " Jayjay corrected quietly. "Uh . . . Yes. But you don't seem to be interested in the modernadventure fiction. May I ask why?" "Sure. " Jayjay found himself becoming irrationally irritated withHull. He knew that the young sociologist had nothing to do with hisown irritation, so he kept the remarks as impersonal as possible. "Inthe first place, you, as a sociologist, should know what market mostfiction is written for. " "Why . . . Uh . . . For people who want to relax and--" "Yes, " Jayjay cut in. "But what kind? The boys on Pluto? The asteroidslicers? No. There are four billion people on Earth and less than fivemillion in space. The market is Earth. "Also, most writers have never been any farther off the surface ofEarth than the few miles up that an intercontinental cruiser takesthem. "And yet, the modern 'adventure' novel invariably takes place inspace. "I can read Westerns because I neither know nor care what the OldAmerican West was _really_ like. I can sit back and sink into thenever-never land that the Western tells about and enjoy myself becauseI am not forced to compare it with reality. "But a 'space novel' written by an Earthside hugger is almost as mucha never-never land, and I have to keep comparing it with what isactually going on around me. And it irritates me. " "But, aren't some of them pretty well researched?" Hull asked. "Obviously, you haven't read many of them, " Jayjay said. "Sure, someof them are well researched. Say one half of one per cent, to beliberal. The rest don't know what they're talking about!" "But--" "For instance, " Jayjay continued heatedly, "you take a look at everyblasted one of them that has anything to do with a spacecraft havingtrouble. They have to have an accident in space in order to disablethe spaceship so that the hairy-chested hero can show what a great guyhe is. So what does the writer do? He has the ship hit by a meteor! Ameteor!" Hull thought that over for a second. "Well, " he said tentatively, "aship _could_ get hit by a meteor, couldn't it?" Jayjay closed his eyes in exasperation. "Of course it could! And anair-ship can run into a ruby-throated hummingbird, too. But how oftendoes it happen? "Look: We're hitting it up at about one-fortieth of the velocity oflight right now. What do you think would happen if we got hit by ameteor? We'd be gone before we knew what had happened. "Why doesn't it happen? Because we can spot any meteor big enough tohurt us long before it contacts us, and we can dodge it or blast itout of the way, depending on the size. "You've seen the outer hull of this ship. It's an inch thick shell ofplastic, supported a hundred feet away from the steel hull by longbooms. Anything small enough to get by the detectors will be smallenough to burn itself out on that hull before it reaches the ship. The--" * * * * * Jayjay Kelvin was not ordinarily a man to make long speeches, especially when he knew he was telling someone something that theyalready knew. But this time, he was beating one of his favorite drums, and he went on with his tirade in a fine flush of fury. Alas . . . Poor Jayjay. Actually, Jayjay Kelvin can't be blamed for his attitude. All he wassaying was that it was highly improbable that a spaceship would be hitby a meteor. In one way, he was perfectly right, and, in another, hewas dead wrong. How small must a piece of matter be before it is no longer a meteor? Fortunately, the big hunks rarely travel at more than about two timesten to the sixth centimeters per second, relative to Sol, in the SolarSystem. But there are little meteors--_very_ tiny ones--that come in, hell-bent-for-leather, at a shade less than the velocity of light. They're called cosmic rays, but they're not radiation in the strictsense of the word. A stripped hydrogen atom, weighing on the order ofthree point three times ten to the minus twenty-second grams, restmass, can come galumping along at a velocity so close to that of lightthat the kinetic energy is something colossal for so small a particle. Protons with a kinetic energy of ten to the nineteenth electron volts, while statistically rare, are not unusual. Now, ten million million million electron volts may be a wee bitmeaningless to the average man, so let's look at it from anotherangle. Consider. According to the well-known formula E = mc^2, a single gramof matter, if converted _completely_ into energy, would yield somenine hundred million million million ergs of energy. An atomic bombyields only a fraction of that energy, since only a small percentageof the mass is converted into energy. If _all_ of the mass of an atomic bomb were converted into energy, thetest in Alamogordo, New Mexico, 'way back in 1945, would probably havebeen the last such test on Earth; there wouldn't have been anyonearound to make a second test. So what does this have to do with cosmic ray particle? Well, if thatatomic bomb had been moving at the velocity with which ourten-to-the-nineteenth-electron-volts proton is moving, it could havebeen made of sand instead of U^235. It would have produced tenthousand million times as much energy as the total disintegration ofthe rest mass would have produced! Kinetic energy, my children, has a great deal more potential thanatomic energy. But we digress. What has all this to do with Jayjay Kelvin? If Jayjay had been a detective story addict instead of a Western storyaddict, he would have heard of the HIBK or "Had I But Known" school ofdetective writing. You know: "Had I But Known that, at that moment, inthe dismal depths of a secret underground meeting place, the evilChuman-Fu was plotting. . . . " If Jayjay Kelvin had known what was going on a few million miles awayfrom the Pluto-bound _Persephone_, he would have kept his mouth shut. * * * * * The cargo-ship _Mordred_ was carrying a cargo of heavy metals sunward. In her hold were tightly-packed ingots of osmium-iridium-platinumalloy, gold-copper-silver-mercury alloy, and small percentages ofother of the heavy metals. The cargo was to be taken to the AsteroidBelt for purification and then shipped Earthward for finaldisposition. The fact that silver had replaced copper for electricalpurposes on Earth was due to the heavy-metals industry on Pluto. Because of Pluto, the American silver bloc had been broken at last. The _Mordred_ was approaching turnover. Now, with a gravito-inertial drive, there is really no need to turn aship over end-for-end as she approaches the mid-point of hertrajectory. Since there is no rocket jet to worry about, all that isreally necessary is to put the engine in reverse. In fact, the patrolships of the Interplanetary Police do just that. But the IP has been trained to take up to five standard gees in anend-to-end flip, and the ships are built to take the stress in bothdirections. An ordinary cargo ship finds it a lot easier to simplyflip the ship over; that way, the stresses remain the same, and theceiling-floor relationship is constant. The _Mordred_ had been having a little trouble with her Number Threedrive engine, so the drive was cut off at turnover, while the engineerreplaced a worn bearing. At the same time, the maintenance officerdecided he'd take a look at the meteor-bumper--the plastic outer hull. Since the ship was in free fall, all he had to do was pull himselfalong one of the beams that supported the meteor-bumper away from themain hull. The end of one of the beams had cracked a part of thebumper hull--fatigue from stress, nothing more, but the hull might aswell be patched while the drive was off. It was a one-man job; the plastic was dense, but under null-geeconditions it was easy to maneuver. The maintenance officer repairedthe slight crack easily, wiped the sticky pre-polymer from the fingersof his spacesuit gloves, and tossed the gooey rag off into space. Thenhe pushed himself back across the vacuum that separated the outer hullfrom the inner, entered the air lock, and reported that the job wasfinished. Five minutes later, the _Mordred_ began decelerating towardthe distant Asteroid Belt. Forget the _Mordred_. The ship is no longer important. Keep your eyeson that rag. It's a flimsy thing, composed of absorbent plastic andgooed up with a little unpolymerized resin, weighing about fiftygrams. It is apparently floating harmlessly in space, just beyond theorbit of Uranus, looking as innocuous as a rag can look. But it ismoving sunward at eight hundred million centimeters per second. * * * * * The _Persephone_ was approaching turnover. The ship's engineerreported that the engines were humming along smoothly, so there was noneed to shut them off; the ship would simply flip over as she ran, making her path a slightly skewed, elongated S-curve--a sort oforbital hiccup. [Illustration] Except that she never quite made it through the hiccup. The ship wasalmost perpendicular to her line of flight when she was sideswiped. Her meteor detectors hadn't failed; they were still functioningperfectly. But meteor detectors are built to look for solid chunks ofmetal and rock--not thin, porous bits of cloth. The rag had traveled a good many millions of miles since it had beencast overboard; it was moving sunward with almost the same velocitywith which the _Persephone_ was moving Plutowards. The combinedvelocities were such that, if it had hit the _Persephone_ dead on, itwould have delivered close to seventeen thousand kilowatt-hours ofenergy in one grand burst of incandescence. Fortunately, the tip of the rag merely gave the ship a slap on thetail as it passed. The plastic meteor-bumper wasn't built to take thatsort of thing. The plastic became an expanding cloud of furiouslyincandescent gas in a small fraction of a second, but the velocity ofthat bit of rag was so great that the gas acted as a solid block ofsuperheated fury as it leaped across the hundred feet of vacuum whichseparated the bumper hull from the inner hull. A rocket-driven missile carrying a shaped-charge warhead weighingseveral hundred pounds might have done almost as much damage. * * * * * Jayjay Kelvin moved his arms to pick himself up off the floor andfound that there was no necessity for doing so. He was floating in theair of the lounge, and, strictly speaking, there was no floor anyway. He opened his eyes and saw that that which had been the floor was nowjust another wall, except that it had chairs bolted to it. It rose onhis left, reached the zenith, and set on his right, to be replaced byanother wall, and then by what had been the ceiling. The second timethe floor came round, Jayjay began to wonder whether he was spinningaround his longitudinal axis or whether the ship was actually rotatingabout him. He closed his eyes again. He didn't feel more than a little dizzy, but he couldn't be surewhether the dizziness was caused by his spinning or the blow on hishead. He opened his eyes again and grabbed at the book that wasorbiting nearby, then hurled it as hard as he could toward thesometime ceiling. "The Pride of the Pecos" zoomed rapidly in onedirection while Jayjay moved sedately in the other. The ship was spinning slightly, all right. When he finally grabbed achair, he found that there was enough spin to give him a weight of anounce or two. He sat down as best he could and took a good lookaround. Aside from "The Pride of the Pecos" and a couple of other books, theair was remarkably free from clutter. There hadn't been much loosestuff laying around. A pencil, a few sheets of paper--nothing more. There was one object missing. Jayjay looked around more carefully, andthis time he saw a hand protruding from the space "beneath" the lowtable. He bent down for a better look and saw that Jeffry Hull wasunconscious. Blood from his nose was spreading slowly over his face, and one eye looked rather battered. Jayjay grasped the protrudingwrist and felt for a pulse. It was pumping nicely. He decided thatHull was in no immediate danger; very few people die of a bloody nose. The lighting in the lounge was none too good; the low-power emergencysystem had come on automatically when the power from the ship'sengines had died. Jayjay wondered just what had happened. There hadbeen a hell of an explosion; that was all he knew. He wondered if anyone else aboard was alive and conscious, and decidedhe might as well find out. He took a long dive toward the centralstairwell that ran the length of the ship's long axis and looked down. The emergency door to the cargo hold was closed. No air, most likely. The way up looked clear, so he scrambled up the spiral stairway. A few feet farther up, he found that he had passed the center of theship's rotation. The _Persephone_ was evidently toppling end-over-end, and the center of rotation was in the lounge itself. The heavy cargo inthe hold was balancing the lighter, but longer, part of the ship above thelounge. He began climbing down the stairwell toward the navigation andcontrol sections. Somewhere down there, somebody was cursing fluently in Arabic. "Illegitimate offspring of a mangy she-camel! Eater of dogs! Wallowerin carrion!" And then, with hardly a break: "Allah, All-Merciful, All-Compassionate! Have mercy on Thy servant! I swear by the beard ofThy holy Prophet that I will attend more closely to my duties to Theeif Thou wilt get me loose from this ill-begotten monstrosity! Help meor I perish!" The last words were a wail. "I'm coming!" boomed Jayjay in the same tongue. "Save thy strength!" * * * * * There was silence from the control room as Jayjay clambered on downthe stairwell. Fortunately, the steps had been built so that it waspossible to use them from either side, no matter which way the gravitypull happened to be. By the time he reached the control room, heweighed a good fifteen pounds. Captain Atef al-Amin was staring up at the stairs as Jayjay came down. He was jammed tightly into a space between two of the big controlcabinets, hanging head downward and looking more disheveled thanJayjay had ever seen the usually immaculately-uniformed captain. "Oh, " said Captain Al-Amin, in English, "it's you. For a moment Ithought--" Then he waved his free hand. "Never mind. Can you get meout of here?" What had been the floor of the control room was now the ceiling. Thetwo steel cabinets which housed parts of the computer unit nowappeared to be bolted to the ceiling. They were only about five feethigh, and the space between them was far too narrow for a man to havegot in there by himself--especially a man of the captain's build. Nonethe less, he was in there--jammed in up to his waist. Only his uppertorso and one arm was free. The other arm was jammed in against thewall. Jayjay took the leap from the stairs and grabbed on to the chair thathung from the ceiling nearby. When you only weigh fifteen pounds, youcan make Tarzan look like an amateur. "You hurt?" he asked. "It isn't comfortable, sure as hell, " said Al-Amin. "I think my arm'sbroken. Think you can get me loose?" "I can try. Give me your hand. " Jayjay took the captain's free handand gave it a tug. Then he released the chair he was holding, bracedboth feet against the panels of the computer housings, and gave a goodpull. The captain didn't budge, but he winced a little. "That hurt?" "Just my arm. The pressure has cut off my blood circulation; my legsare numb, and I can't tell if they hurt or not. " Jayjay grabbed the chair again and surveyed the situation. "Where'syour First Officer?" "Breckner? Down in the engine room. " Jayjay didn't comment on that. If the hold was airless, it was likelythat the engine room was, too, and there was no need to worry Al-Aminany more than necessary just now. "Can you use a cutting torch?" the captain asked. "Yes, but I don't think it'll be necessary, " Jayjay said. "Hold on aminute. " He went back up the stairs to the officers' washroom and, after a little search, got a container of liquid soap from thesupplies. Then he went back down to the control room. He made the jumpto the chair, holding on with one hand while he held the container ofsoap with the other. "Can you hold me up with one hand? I'll need both hands to work with. " "In this gravity? Easy. Give me your belt. " Captain Atef Al-Amin grabbed Jayjay's belt and hung on, while Jayjayused both hands to squirt the liquid soap all over the captain fromthe waist down. It would have made a great newspaper photo. Captain Al-Amin, wedgedbetween two steel cabinets, hanging upside-down under a pull ofone-fifteenth standard gee, holding up his rescuer by the belt. Therescuer, right-side-up, was squeezing a plastic container of liquidsoap and directing the stream against the captain. When Al-Amin was thoroughly wetted with the solution, Jayjay againbraced his feet against the steel panels and pulled. With a slick, slurping sound, the captain slid loose, and the two ofthem toppled head-over-heels across the room. Jayjay was prepared forthat; he stopped them both by grasping an overhead desk-top as theywent by. Then he let go, and the two men dropped slowly to what hadbeen the ceiling. "_Hoo!_" said the captain. "That's a relief! Allah!" Jayjay took a look at the man's arm. "Radius might be broken; ulnaseems O. K. We'll splint it later. Your legs are going to tingle likecrazy when the feeling comes back. " "I know. But we have other things to worry about, Mr. Kelvin. Evidently you and I are the only ones awake so far, and I'm in nocondition to go moving all over this spinning bucket just yet. Wouldyou do some reconnoitering for me?" "Sure, " said Jayjay. "Just tell me what you want. " * * * * * Within half an hour, the news was in. There were five men alive in the ship: Jayjay, Captain Al-Amin, JeffryHull, Second Officer Vandenbosch, and Maintenance Officer Smith. Vandenbosch had broken both legs and had to be strapped into a bunkand given a shot of narcolene. Jayjay had put on a spacesuit and taken a look outside. The whole rearend of the ship was gone, and with it had gone the First Officer, theRadio Officer, and the Engineering Officer. And, of course, the mainpower plant of the ship. Most of the cargo hold was intact, but the walls had been breached, and the air was gone. "Well, that's that, " said Captain Al-Amin. Jayjay, Smith, Hull, andthe captain were in the control room, trying not to look glum. "I wishI knew what happened. " "Meteor, " Jayjay said flatly. "The bumper hull is fused at the edgesof the break, and the direction of motion was inward. " "I don't see how it could have got by the meteor detectors, " saidSmith, a lean, sad-looking man with a badly bruised face. "I don't either, " the captain said, "but it must have. If the engineshad blown, the damage would have been quite different. " Jeffry Hull nervously took a cigarette from his pocket pack. His nosehad quit bleeding, but his eye was purpling rapidly and was almostswollen shut. Captain Al-Amin leaned over and gently took the cigarette from Hull'sfingers. "No smoking, I'm afraid. We'll have to conserve oxygen. " "You guys are so damn _calm_!" Hull said. His voice betrayed a surfaceof anger covering a substratum of fear. "Here we are, heading awayfrom the Solar System at eighteen million miles an hour, and you allact as if we were going on a picnic or something. " The observation was hardly accurate. Any group of men who went on apicnic in the frame of mind that Jayjay and the others were in wouldhave produced the gloomiest outing since the Noah family took a tripin an excursion boat. "There's nothing to worry about, " Captain Al-Amin said gently. "All wehave to do is set the screamers going, and the Interplanetary Policewill pick us up. " "Screamers?" Hull looked puzzled. Instead of answering the implied question, the captain looked atSmith. "Have you checked them?" He knew that Smith had, but he wastrying to quiet Hull's fears. Smith nodded. "They're O. K. " He looked at Hull. "A screamer is anemergency radio. There's one in every compartment. You've seen them. "He pointed across the room, toward a red panel in the wall. "Inthere. " "But I thought it was impossible for a spaceship in flight to contacta planet by radio, " Hull objected. "Normally, it is, " Smith admitted. "It takes too much power and tootight a beam to get much intelligence over a distance that great froma moving ship. But the screamers are set up for emergency purposes. They're like flares, except that they operate on microwave frequenciesinstead of visible light. "The big radio telescopes on Luna and on the Jovian satellites canpick them up if we beam them sunward, and the Plutonian station canpick us up if we beam in that direction. " Hull looked much calmer. "But where do you get the power if theengines are gone? Surely the emergency batteries won't supply thatkind of power. " "Of course not. Each screamer has its own power supply. It's ahydrogen-oxygen fuel cell that generates a hell of a burst of powerfor about thirty minutes before it burns out from the overload. It'smeant to be used only once, but it does the job. " "How do they know where to find us from a burst like that?" Hullasked. "Well, suppose we only had one screamer. We'd beam it toward Pluto, since it would be easier for an IP ship to get to us from there. Sinceall screamers have the same frequency--don't ask me what it is; I'mnot a radio man--the velocity of our ship will be indicated by theDoppler Effect. That is, our motion toward or away from them can becalculated that way. Our angular velocity with respect to them can bechecked while the screamer is going; they will know which directionwe're moving, if we're moving at an angle. "With that information, all they have to do is find out which ship isin that general area of the sky, which they can find out by checkingthe schedule, and they can estimate approximately where we'll be. TheIP ship will come out, and when they get in the general vicinity, theycan find us with their meteor detectors. Nothing to it. " "And, " Captain Al-Amin added, "since we have eight screamers stillleft with us, we have plenty of reserves to call upon. There'snothing to worry about, Mr. Hull. " "But how can you aim a beam when we're toppling end-over-end likethis?" Hull asked. "Well, if we couldn't stop the rotation, " said the captain, "we'dbroadcast instead of beaming. Anywhere within the Solar System, ascreamer can broadcast enough energy to overcome the background noise. "The IP would have a harder time finding us, of course, but we'd besaved eventually. " "I see, " said Hull "How do we go about stopping the rotation?" "That's the next thing on the agenda, " Al-Amin said. "This seasickroll is caused by the unevenness of the load, and I'm pretty sick ofit, myself. Smith, will you and Mr. Kelvin get out the emergencyrockets? We'll see what we can do to stabilize our platform. " * * * * * It took better than an hour to get the ship straightened out. For themain job, emergency rockets were set off at the appropriate spotsaround the hull to counteract the rotation. The final trimming wasdone with carbon dioxide fire extinguishers, which Smith and JayjayKelvin used as jets. Getting a fix on Pluto was easy enough; the lighthouse station at Styxbroadcast a strong beep sunward every ten seconds. They could alsopick up the radio lighthouses on Eros, Ceres, Luna, and Mimas. Evidently, the one on Titan was behind the Jovian bulk. They were ready to send their distress call. "It's simple, " Smith said as he opened the red panel in the wall ofthe control room. "First we turn on the receiver. " He pushed a buttonmarked _R_. "Then we turn these two wheels here until the pip on thatlittle screen is centered. That's the signal from Pluto. It comes instrong every ten seconds, see?" Jayjay watched with interest. He'd heard about screamers and had seenthem, but he'd never had the opportunity of observing one in action. Like flares or bombs, they were intended for one-time use. Theinstructions were printed plainly on the inside of the red door, andSmith was simply reading off what was printed there. "These wheels, " he was saying, "line up the parabolic reflector withthe Pluto signal, you see. There. Now we've got it centered. Now, allwe have to do is make one small correction and we're all set. Thesethings are built so that they're fool-proof; a kid could operate it. Watch. " Facing each other across a small gap were a pair of tapered screwplugs, one male and one female. The male was an average of half aninch in diameter; the female was larger and bored to fit the male. "The female plug, " Smith said, "leads to two tanks of high-pressuregas inside this cabinet on the left. One tank of oxygen, one ofhydrogen. See how this male plug telescopes out to fit into thefemale? All we have to do is thread them together, and everything isautomatic. " Jayjay was aware that Smith's explanations were meant to give JeffryHull something to think about instead of his fears. Hull was basicallyan Earth-hugger, and free fall did nothing to keep him calm. Evidentlyhis subconscious knew that he had to latch on to something to keep hismental equilibrium, because he showed a tremendous amount of interestin what should have been a routine operation. "How do you mean, it's all automatic?" he asked. "What happens?" "Well, you can't see into the female plug, but look here at the male. See those concentric tubes leading into the interior of the cabinet onthe right? The outer one leads in the oxygen, the inner leads in thehydrogen. We need twice as much hydrogen as oxygen, so the inner tubehas twice the volume delivery as the outer. See?" "Yes. But what is the solid silver bar in the center of the innertube?" "That's the electrical connection for the starter battery. There's asmall, short-lived chemical battery, like the ones in an ordinarypocket radio, except that they're built to deliver a high-voltage, high-amperage current for about a tenth of a second. That activatesthe H-O cell, you see. Also, that silver stud depresses thecorresponding stud in the female plug, which turns on the gas flowbefore it makes the connection with the starter battery. Follow?" Hull didn't look as though he did, but he nodded gamely. "Then whathappens?" "Then the hydrogen and the oxygen come together in the fuel cell and, instead of generating heat, they generate electric current. Thatcurrent is fed into the radio unit, and the signal is sent to Pluto. Real simple. " "I see, " Hull said. "Well . . . Go ahead. " Smith telescoped the two leads together and began turning the collaron the female plug. He screwed it up as far as it would go. And nothing happened. "What the hell?" asked Smith of no one in particular. He tried totwist it a little harder. Nothing happened. The threads had gone asfar as they would go. "What's the matter?" Jayjay asked. "Damfino. No connection. Nothing's happening. And it's as tight as itwill go. " "Are the gases flowing?" Jayjay asked. "I don't know. These things aren't equipped with meters. They'resupposed to work automatically. " Jayjay pushed Smith aside. "Let me take a look. " Smith frowned as though he resented an ordinary passenger shoving himaround, but Jayjay ignored him. He cocked his head to one side andlooked at the connection. "Hm-m-m. " He touched it with a finger. Thenhe wet the finger with his tongue and touched the connection again. "There's no gas flow, Smith. " "How do you know?" Smith was still frowning. "There's a gap there. That tapered thread isn't in tight. If therewere any gas flowing, it would be leaking out. " Before Smith could sayanything Jayjay began unscrewing the coupling. When it came apart, itlooked just the same as it had before Smith had put it together. In the dim glow from the emergency lights, it was difficult to seeanything. "Got an electric torch?" Jayjay asked. Smith pushed himself away from the screamer panel and came back aftera moment with a flashlight. "Let me take a look, " he said, edgingJayjay aside. He looked over the halves of the coupling verycarefully, then said: "I don't see anything wrong. I'll try it again. " "Hold on a second, " Jayjay said quietly. "Let me take a look, willyou?" Smith handed him the torch. "Go ahead, but there's nothing wrong. " * * * * * Jayjay took the light and looked the connections over again. Then hescrewed his head around so that he could look into the female plug. "Hm-m-m. Hard to count. Gap's too small. Anybody got a toothpick?" Nobody did. Jayjay turned to Jeffry Hull. "Mr. Hull, would you mind going to thelounge? I think there's some toothpicks in the snack refrigerator. " "Sure, " said Hull. "Sure. " He pushed himself across the control room and disappeared through thestairwell. "Get several of them, " Jayjay called after him. Captain Al-Amin said: "What's the trouble, Mr. Kelvin?" "I'm not sure yet, " Jayjay answered. "When did you last have thescreamer units inspected?" "Just before we took off from Jove Station, " Al-Amin said. "That's thelaw. All emergency equipment has to be checked before takeoff. Why?What's the matter?" "Did they check this unit?" Jayjay asked doggedly. "Certainly. I watched them check it myself. I--" He brought himself upshort and said: "Give me that torch, will you? I want to take a lookat the thing. " Jayjay handed him the flashlight and grasped the captain's belt. Withone arm in a splint, Al-Amin couldn't hold the flashlight and hold onto anything solid at the same time. "I don't see anything wrong, " he said after a minute. "Neither do I, " Jayjay admitted. "But the way it acts--" "I got the toothpicks!" Jeffry Hull propelled himself across the roomtoward the three men who were clustered around the screamer. Jayjay took the toothpicks, selected one, and inserted it into thefemale plug. "Hard to see those threads with all the tubes blockingthat plug, " he said offhandedly. Hull said: "Captain, did you know that the refrigerator is off?" "Yes, " said Atef Al-Amin absently. "It isn't connected to theemergency circuits. Wastes too much energy. What do you find, Mr. Kelvin?" After a second's silence, Jayjay said: "Let me check once more. " Hewas running the tip of the toothpick across the threads in the femaleplug, counting as he did so. "Uh-huh, " he said finally, "just as Ithought. There's one less thread in the female plug. The male plug isstopped before it can make contact. There's a gap of about a tenth ofan inch when the coupling is screwed up tight. " "Let me see, " Smith said. He took the toothpick and went through thesame operation. "You're right, " he said ruefully, "the female plug isfaulty. We'll have to use one of the other screamers. " "Right, " said Jayjay. Wrong, said Fate. Or the Powers That Be, or the Fallibility of Man, whatever you want to call it. Every screamer unit suffered from the same defect. * * * * * "I don't understand it!" A pause. "It's impossible! Those units weretested!" For the first time in his life, Captain Atef Abdullah Al-Amin allowedhis voice to betray him. Arabic is normally spoken about half an octave above the normal toneused for English. And, unlike American English, it tends to waver upand down the scale. Usually, the captain spoke English in the flat, un-accented tones of the Midwest American accent, and spoke Arabic inthe ululating tones of the Egyptian. But now he was speaking English with an Egyptian waver, not realizingthat he was doing it. "How could it happen? It's ridiculous!" The captain, his maintenance officer, and Jeffry Hull were clusteredaround the screamer unit in the lounge. Off to one side, Jayjay Kelvinheld a deck of cards in his hands and played a game of patience called"transportation solitaire. " His eyes didn't miss a play, just as hisears didn't miss a word. He pulled an ace from the back of the deck and flipped it to thefront. "You said the screamers had been checked, " Jeffry Hull saidaccusingly. "How come they _weren't_ checked?" "They _were_!" Al-Amin said sharply. "Sure they were, " Smith added. "I watched the check-off. There wasnothing wrong then. " "Meanwhile, " Hull said, the acid bite of fear in his voice, "we haveto sit here and wait for the Interplanetary Police to find us by pureluck. " The captain should have let Hull cling to the idea that the IP couldfind the _Persephone_, even if no signal was sent. But the captain wasalmost as angry and flustered as Hull was. [Illustration] "Find us?" he snapped. "Don't be ridiculous! We won't even be misseduntil we're due at Styx, on Pluto, nine days from now. By that time, we'll be close to two billion miles beyond the orbit of Pluto. We'llnever be found if we wait 'til then. Something has to be done _now_!"He looked at his Maintenance Officer. "Smith, isn't there some way tomake contact between those two plugs?" "Sure, " Smith said bitterly. "If we had the tools, it would be ducksoup. All we'd have to do is trim down the male plug to fit thefemale, and we'd have it. But we don't have the tools. We've got acouple of files and a quarter-horsepower electric drill with one bit. Everything else was in the tool compartment--which is long gone, withthe engine room. " "Can't you . . . Uh, what do you call it? Uh . . . Jury-something--"Hull's voice sounded as though he were forcing it to be calm. "Jury-rig?" Smith said. "Yeah? With what? Dammit, we haven't got anytools, and we haven't got any materials to work with!" "Can't you just use a wrench to tighten them more?" Hull askedhelplessly. Smith said a dirty word and pushed himself away from the screamer unitto glower at an unresisting wall. "No, Mr. Hull, we couldn't, " said Captain Al-Amin with restrainedpatience. "That would strip the threads. If the electrical contactwere made at the same time, the high-pressure oxygen-hydrogen flowwould spark off, and we'd get a big explosion that would wreckeverything--including us. " Then he muttered to himself: "I still don'tsee how it could happen. " Jayjay Kelvin pulled a nine of spades from the back of the deck to thefront. It matched the four of spades that had come three cardsbefore. Jayjay discarded the two cards between the spades. "Youdon't?" he asked. "Didn't you ever hear that the total is greater thanthe sum of its parts?" "What?" Captain Al-Amin sounded as though he'd been insulted--inArabic. "What are you talking about, Mr. Kelvin?" "I'm talking about the idiocy of the checking system, " Jayjay saidflatly. "Don't you see what they did? Don't you see what happened?Each part of a screamer has to be checked separately, right?" Al-Amin nodded. "Why? Because the things burn out if you check them as a completeunit. It's like checking a . 50 caliber cartridge. The only way you cancheck a cartridge is to shoot it in a gun. If it works, then you knowit works. Period. The only trouble is that you've wasted thecartridge. You know that _that_ one is good, but you've ruined it. "Same way with a screamer. If you test it as a unit, you'll ruin it. So you test it a part at a time. All the parts check out nicelybecause the test mechanisms are built to check each part. " Smith squinted. "Well, sure. If you check out the whole screamer, you'll ruin it. So what?" "So suppose you were going to check out a cartridge, " Jayjay said. "You don't fire it; you check each part separately. You check thebrass case. It's all right; the tests show that it won't burst underfiring pressure. You check the primer; the tests show that it willexplode when hit by the gun's hammer. You check the powder; the testsshow that the powder will burn nicely when the flame from the primerhits it. You check the bullet; the tests show that the slug will beexpelled at the proper velocity when the powder is ignited. "So you assume that the cartridge will function when fired. "But will it?" "Why wouldn't it?" Smith asked. "Because the flame from the exploding primer can't reach the powder, that's why!" Jayjay snapped. "Some jerk has redesigned the primer sothat the flame misses the propellant!" "How could that happen?" Hull asked blankly. "How? Because Designer _A_ decided that the male plug on the screamershould have one more turn on its threads, but he forgot to tellDesigner _B_, who designs the female plug, that the two should match. The testing equipment is designed to test each part, so each parttests out fine. The only trouble is that the thing doesn't test out asa whole. " * * * * * Captain Al-Amin nodded slowly. "That's right. The test showed that theoxyhydrogen section worked fine. It showed that the starter workedfine. It showed that the radiowave broadcaster worked fine. But itdidn't show that they'd work together. " Smith said a short, five-letter word. It was French; the Anglo-Saxonequivalent has only four letters. "What good does all this theorizingdo us?" he added. "The question is: How do we fix the thing?" "Well, can't you put another turn on the thread?" Hull asked. "Oh, sure, " Smith said sarcastically. "You give me a lathe and theproper tools, and I'll make you all the connections you want. Hell, ifI had the proper tools, I could turn us out a new spaceship, and wecould all go home in comfort. " "Couldn't you drill out the metal with that drill?" Hull askedplaintively. "No!" Smith said harshly. "How do you expect me to get a quarter-inchbit into a space less than a sixteenth of an inch in diameter?" Hull wasn't used to machinist's terms. "How big is an inch?" "Two point five four oh oh oh five centimeters, " Smith said in a nastytone of voice. "Does that help you any?" "I'm just trying to help!" Hull snapped. "You've got no call to getsarcastic with me!" Smith said the French word again. "Enough!" the captain barked. "Smith, control your tongue! That sortof thing won't help us. " He jerked his head around. "Mr. Kelvin, doyou have any suggestions?" Jayjay played another card. "No. Not yet. I'm thinking. " "Smith? Any ideas?" The tone of the Arab's voice left no doubt that hemeant business. "No, sir. Without a properly equipped machine shop, there's nothing wecan do. " "How so?" "Because that's a precision job, sir. The threads are tapered so thatthe fit will be gas-tight. That's why the threads have aten-thousandth of an inch of soft polyethylene covering the hardsteel, so that when the threads are tight, the polyethylene will actas a seal. Everything in that connection is a precision fitted job. The ends of the tubes are made to be slightly mashed together, so thatthe seals will be tight--they're coated with polyethylene, too. If theoxygen and hydrogen mix, the efficiency of the fuel cell goes down tozero, and you run the chance of an explosion. " "Show me, " Al-Amin said. Smith took a pencil out of his pocket and began drawing a crosssection of the connection on the top of the nearby table. "Look here, captain, this is the way the two are supposed to fit. Butthey don't, because the male plug can't get far enough into the femalesocket to make the connection. Like this, see?" The captain nodded. "Well, " Smith continued, "there's a thirty-second of an inch clearancethere. If the female had one more turn of thread, the fit would beprefect. As it is, we get no connection. So the screamer doesn'tfunction. " Al-Amin looked at the drawing. "Odd that there's never been anycomplaint about this error before. " Jayjay turned another ace. "Not so odd, really. " All heads turned toward Jayjay. "What does that mean?" Smith asked. "Just what I said. " Jayjay turned another card. "A screamer issupposed to call for help, isn't it? It's only used in a direemergency. Then the only test of the whole unit comes when theoccupants of the spaceship are in danger--as we are. If the thingsdon't work, how could there be any complaint? If we can't get ours towork, will we complain? To whom? "How many ships have been reported missing in the past year or so? Allof them presumed lost because of meteor strikes, eh? If a ship is lostand doesn't signal, we presume that it was totally destroyed. If itwasn't, they'd have signaled. As _Mister_ Smith says: See?" There was a long silence. Jayjay Kelvin turned the last card, saw that he had lost, and beganshuffling the deck. * * * * * "I think I've got it, " Smith said excitedly, several hours later. Captain Al-Amin glanced around. Hull was dozing fitfully a few inchesabove the couch. Jayjay Kelvin was still methodically playingsolitaire. "Keep your voice down, " the captain ordered. "No use giving ourpassengers false hopes. What do you mean, you've got it?" "Simple. Real simple. All we have to do is file off the last thread ofthe male plug. Then it will fit into the female. " Smith's voice was ahoarse whisper. "Won't work, " said Jayjay Kelvin from across the room. Smith blew up. "How do you know?" he roared. "You sit over theremaking wiseacre remarks and do nothing! Play cards, that's all! Whatdo you know about things like this, _Mister_ Joseph Kelvin? What doesa businessman know about mechanical equipment?" "Enough, " Jayjay said quietly. "Enough to know that, if you try tofile off the final thread of the male plug, you'll do an uneven job. And that will mean leakage. " "What do you mean, an uneven job?" Smith was still furious. "Trimming off the end of the male plug would have to be done on alathe, " Jayjay said, without looking up from his cards. "Otherwise, the fit would be wrong, and the gases would mix. And we would all go_phfft!_ when the mixture blew. " Smith started to say something, but Jayjay went right on talking. "Even if we had a lathe, the male plug doesn't turn, so you'd be outof luck all the way. You can't take the screamers apart withoutwrecking them--not without a machine shop. You're going to have towork on that female connection. She's got a sleeve on her that willturn. Now, if--" Jayjay's voice faded off into silence, and hismanipulations of the cards became purely mechanical. "Huh!" Smith said softly. "Just because he's related to KelvinAssociates, he thinks he's hot--" He said the French word again. "Is he right?" Captain Al-Amin asked sharply. "Well--" Smith rubbed his nose with a forefinger. "Well, yes. I waswrong. We can't do it with a file. It would have to be turned on alathe, and we don't have a lathe. And we don't have any measuringinstruments, either. This is a precision job, as I said. And we don'thave a common ruler aboard, much less a micrometer. Any makeshift jobwill be a failure. " Captain Al-Amin brooded over that for a moment. Then he looked atJayjay again. "Mr. Kelvin. " "Yes, captain?" Jayjay didn't look up from the cards in his hands. "_Are_ you related to Kelvin Associates?" "In a way. " Al-Amin bit at his lower lip. "Mr. Kelvin, you registered aboard thisship as Joseph Kelvin. May I ask if your middle name is James?" After a short pause, Jayjay said: "Yes. It is. " "Are you _the_ J. J. Kelvin?" "Yup. But I'd rather you didn't mention it when we get to Pluto. " Smith's jaw had slowly sagged during that conversation. Then he closedhis mouth with a snap. "You're Jayjay Kelvin?" he asked, opening hismouth again. "That's right. " "Then I apologize. " "Accepted, " said Jayjay. He wished that Smith hadn't apologized. "Why didn't you say so in the first place?" Captain Al-Amin asked. "Because I didn't want it known that I was going to Pluto, " Kelvinsaid. "And--after the accident happened--I kept quiet because I knowhuman nature. " Jeffry Hull, who had awakened during the argument, looked at Jayjayand said: "What's human nature got to do with it, Mr. Kelvin?" "Nothing, except that if I'd told everyone I was J. J. Kelvin, all ofyou would have been sitting around waiting for me to solve the probleminstead of thinking about it yourselves. " Hull nodded thoughtfully. "It makes sense, Mr. Kelvin. If they'd knownthat you were . . . Well . . . Mister Spaceship Himself, they'd have letyou do all the thinking. And that would have left you high and dry, wouldn't it?" Jayjay put the deck of cards in his pocket. "You're a pretty goodsociologist, after all, Mr. Hull. You're right. Face any group withAuthority--with a capital _A_--and they quit thinking for themselves. And if they do, then the poor slob of an Authority doesn't haveanything to tickle his own brains, so everybody loses. " "Well, _do_ you have an answer?" Captain Al-Amin asked. Jayjay shook his head. "Not yet. I think I've got one coming up, but Iwish you two would go on talking while I think. " "I'll try, " Smith said wryly. * * * * * The problem was both simple and complex. The female socket lacked onesingle turn of thread to make a perfect connection. A few hundredthsof an inch separated success from disaster. Five men, including the unconscious Vandenbosch, were only a fractionof an inch away from death. Jayjay Kelvin listened to Smith talk for another half hour, throwingin objections when necessary, but offering no opinions. "All we have to do, " Smith said at last, "is get rid of that littlebit of metal beyond the thread in the female socket. But there's noway to get it out. We can't use a chisel because the force would warpthe threads. Besides, we couldn't get a chisel in there. " "And we don't have a chisel, " Captain Al-Amin added. "We don't haveany tools at all. " "Except, " said Jayjay, "an electric hand drill and a quarter-inchbit. " "Well, sure, " said Smith. "But what good will that do us?" "If we rigged a belt between the drill's motor and the sleeve of thefemale socket, the sleeve would rotate as if it were on a lathe, wouldn't it?" Smith blinked. "Sure. Yeah! Hey!" His face brightened. Then it lookedsad again. "But what good would that do us?" "You said that all we have between us and success is a fraction of aninch of metal. If we can remove that fraction of an inch, we'resuccessful. " "But how can you put a thread into that socket?" Smith asked. Jayjay beamed as though it were his birthday. "We don't have to put athread in there. All we have to do is give the thread on the male plugroom to move in. All we have to do is clear away that metal. So we'lluse the drill motor to turn the sleeve as if it were on a lathe. " Smith still didn't look enthusiastic. "All right. We have a lathe. Butwhat are we going to use for tools? What are we going to cut the metalwith?" Jayjay's smile became broader. "Carbon steel. What else?" "Oh?" said Smith. "And where do we get these tools, Mr. Kelvin? Fromthe circumambient ether?" "Not at all, " said Jayjay. "Did you ever chip flint?" "What?" "Never mind. All we have to do is use that quarter-inch bit. " Smith still looked confused. "I don't get it. A bit that big won't fitin. " "We simply crack a piece off that hard carbon steel, " Jayjay said. "Wecan make a lathe tool that will fit into the small space between theinner and outer tubes. The fractured edge will be sharp enough to takeout the excess metal. The male plug can move in, and we'll havecontact. " "Well, I'll be--" Smith used another French word. Captain Atef Al-Amin cast his eyes upwards. "_Creatio ex nihilo_, " hesaid softly. * * * * * When the Interplanetary Police ship took the five men and the cargofrom the wreck of the _Persephone_, the major in command of the ship, who knew that he had rescued the great J. J. Kelvin, asked him: "Mr. Kelvin, what do you plan to do when you return to Ceres City?" And Jayjay, who knew that both he and the major were speaking for thenewsfacs and for posterity, said: "I'm going to make sure that Kelvin Associates learns to makeemergency equipment properly. We will never again put faulty equipmentaboard a ship. " The major looked perplexed. "What?" "I'm going to have some designer's head!" said Jayjay Kelvin. THE END * * * * *