The Black Star Passes

by Jr. John W. Campbell

  II

  Five men were seated about the Morey library, discussing the results ofthe last raid, in particular as related to Arcot and Morey. Fuller, andPresident Morey, as well as Dr. Arcot, senior, and the two young menthemselves, were there. They had consistently refused to tell what theirtrip had revealed, saying that pictures would speak for them. Now theyturned their attention to a motion picture projector and screen thatArcot junior had just set up. At his direction the room was darkened;and he started the projector. At once they were looking at the threedimensional image of the mail-room aboard the air liner.

  Arcot commented: "I have cut out a lot of useless film, and confined thepicture to essentials. We will now watch the pirate at work."

  Even as he spoke they saw the door of the mail-room open a bit, andthen, to their intense surprise, it remained open for a few seconds,then closed. It went through all the motions of opening to admitsomeone, yet no one entered!

  "Your demonstration doesn't seem to show much yet, son. In fact, itshows much less than I had expected," said the senior Arcot. "But thatdoor seemed to open easily. I thought they locked them!"

  "They did, but the pirate just burned holes in them, so to save propertythey leave 'em unlocked."

  Now the scene seemed to swing a bit as the plane hit an unusually badair bump, and through the window they caught a glimpse of one of thecircling Air Guardsmen. Then suddenly there appeared in the air withinthe room a point of flame. It hung in the air above the safe for aninstant, described a strangely complicated set of curves; then, as ithung for an instant in mid-air, it became a great flare. In an instantthis condensed to a point of intensely brilliant crimson fire. Thisdescribed a complex series of curves and touched the top of the safe. Inan inconceivably short time, the eight-inch thickness of tungsto-iridiumalloy flared incandescently and began to flow sluggishly. A large circleof the red flame sprang out to surround the point of brilliance, andthis blew the molten metal to one side, in a cascade of sparks.

  In moments, the torch had cut a large disc of metal nearly free;seemingly on the verge of dropping into the safe. Now the flame left thesafe, again retracting itself in that uncanny manner, no force seemingeither to supply it with fuel or to support it thus, though it burnedsteadily, and worked rapidly and efficiently. Now, in mid-air, it hungfor a second.

  "I'm going to work the projector for a few moments by hand so that youmay see this next bit of film." Arcot moved a small switch and themachine blinked, giving a strange appearance to the seemingly solidimages that were thrown on the screen.

  The pictures seemed to show the flame slowly descending till it againtouched the metal. The tungsto-iridium glowed briefly; then, as suddenlyas the extinguishing of a light, the safe was gone! It had disappearedinto thin air! Only the incandescence of the metal and the flame itselfwere visible.

  "It seems the pirate has solved the secret of invisibility. No wonderthe Air Guardsmen couldn't find him!" exclaimed Arcot, senior.

  The projector had been stopped exactly on the first frame, showing theinvisibility of the safe. Then Arcot backed it up.

  "True, Dad," he said, "but pay special attention to this next frame."

  Again there appeared a picture of the room, the window beyond, the mailclerk asleep at his desk, everything as before, except that where thesafe had been, _there was a shadowy, half visible safe_, the metalglowing brightly. Beside it there was visible a shadowy man, holdingthe safe with a shadowy bar of some sort. And through both of them theframe of the window was perfectly visible, and, ironically, an AirGuardsman plane.

  "It seems that for an instant his invisibility failed here. Probably itwas the contact with the safe that caused it. What do you think, Dad?"asked Arcot, junior.

  "It does seem reasonable. I can't see off-hand how his invisibility iseven theoretically possible. Have you any ideas?"

  "Well, Dad, I have, but I want to wait till tomorrow night todemonstrate them. Let's adjourn this meeting, if you can all cometomorrow."

  * * * * *

  The next evening, however, it seemed that it was Arcot himself who couldnot be there. He asked Morey, junior, to tell them he would be therelater, when he had finished in the lab.

  Dinner was over now, and the men were waiting rather impatiently forArcot to come. They heard some noise in the corridor, and looked up, butno one entered.

  "Morey," asked Fuller, "what did you learn about that gas the pirate wasusing? I remember Arcot said he would have some samples to analyze."

  "As to the gas, Dick found out but little more than we had alreadyknown. It is a typical organic compound, one of the metal radical type,and contains one atom of thorium. This is a bit radioactive, as youknow, and Dick thinks that this may account in part for its ability tosuspend animation. However, since it was impossible to determine themolecular weight, he could not say what the gas was, save that theempirical formula was C_{62}TH H_{39}O_{27}N_{5}. It broke down at atemperature of only 89 deg. centigrade. The gases left consisted largely ofmethane, nitrogen, and methyl ether. Dick is still in the dark as towhat the gas is." He paused, then exclaimed: "Look over there!"

  The men turned with one accord toward the opposite end of the room,looked, and seeing nothing particularly unusual, glanced back ratherpuzzled. What they then saw, or better, failed to see, puzzled themstill more. Morey had disappeared!

  "Why--why where--ohhh! Quick work, Dick!" The senior Arcot beganlaughing heartily, and as his astonished and curious companions lookedtoward him, he stopped and called out, "Come on, Dick! We want to seeyou now. And tell us how it's done! I rather think Mr. Morey here--Imean the visible one--is still a bit puzzled."

  There was a short laugh from the air--certainly there could be nothingelse there--then a low but distinct click, and both Morey and Arcot weremiraculously present, coming instantaneously from nowhere, if one'ssenses could be relied on. On Arcot's back there was strapped a largeand rather hastily wired mechanism--one long wire extending from it outinto the laboratory. He was carrying a second piece of apparatus,similarly wired. Morey was touching a short metal bar that Arcot heldextended in his hand, using a table knife as a connector, lest they getradio frequency burns on making contact.

  "I've been busy getting the last connection of this portable apparatusrigged up. I have the thing in working order, as you see--or rather,didn't see. This other outfit here is the thing that is more importantto us. It's a bit heavy, so if you'll clear a space, I'll set it down.Look out for my power supply there--that wire is carrying a ratherdangerously high E.M.F. I had to connect with the lab power supply to dothis, and I had no time to rig up a little mechanism like the one thepirate must have.

  "I have duplicated his experiment. He has simply made use of a principleknown for some time, but as there was no need for it, it hasn't beenused. It was found back in the early days of radio, as early as thefirst quarter of the twentieth century, that very short wavelengthseffected peculiar changes in metals. It was shown that the plates oftubes working on very short waves became nearly transparent. The waveswere so short, however, that they were economically useless. They wouldnot travel in usable paths, so they were never developed. Furthermore,existing apparatus could not be made to handle them. In the last warthey tried to apply the idea for making airplanes invisible, but theycould not get their tubes to handle the power needed, so they had todrop it. However, with the tube I recently got out on the market, it ispossible to get down there. Our friend the pirate has developed thisthing to a point were he could use it. You can see that invisibility,while interesting, and a good thing for a stage and televisionentertainment, is not very much of a commercial need. No one wants to beinvisible in any honest occupation. Invisibility is a tremendous weaponin war, so the pirate just started a little private war, the only way hecould make any money on his invention. His gas, too, made the thingattractive. The two together made a perfect combination for criminaloperations.

  "The whole thing looks to me to be the work of a slightly
unbalancedmind. He is not violently insane; probably just has this one particularobsession. His scientific bump certainly shows no sign of weakness. Hemight even be some new type of kleptomaniac. He steals things, and hehas already stolen far more than any man could ever have any need of,and he leaves in its place a 'stock' certificate in his own company. Heis not violent, for hasn't he carefully warned the men not to use theC-32L mask? You'll remember his careful instructions as to how to revivethe people!

  "He has developed this machine for invisibility, and naturally he canfly in and out of the air guard, without their knowing he's there,provided their microphonic detectors don't locate him. I believe he usessome form of glider. He can't use an internal combustion engine, for theexplosions in the cylinders would be as visible as though the cylinderswere made of clear quartz. He cannot have an electric motor, for thestorage cells would weigh too much. Furthermore, if he were using anysort of prop, or a jet engine, the noise would give him away. If he useda glider, the noise of the big plane so near would be more than enoughto kill the slight sounds. The glider could hang above the ship, thendive down upon it as it passed beneath. He has a very simple system ofanchoring the thing, as I discovered to my sorrow. It's a powerfulelectro-magnet which he turns on when he lands. The landing deck of thebig plane was right above our office aboard, and I found my watch wasdoing all sorts of antics today. It lost an hour this morning, and thisafternoon it gained two. I found it was very highly magnetized--I couldpick up needles with the balance wheel. I demagnetized it; now it runsall right.

  "But to get back, he anchors his ship, then, leaving it invisible, hegoes to the air lock, and enters. He wears a high altitude suit, and onhis back he has a portable invisibility set and the fuel for his torch.The gas has already put everyone to sleep, so he goes into the ship,still invisible, and melts open the safe.

  "His power supply for the invisibility machine seems to be somewhat of aproblem, but I think I would use a cylinder of liquid air, and have asmall air turbine to run a high voltage generator. He probably uses thesame system on a larger scale to run his big machine on the ship. Hecan't use an engine for that either.

  "That torch of his is interesting, too. We have had atomic hydrogenwelding for some time, and atomic hydrogen releases some 100,000calories per mole of molecular hydrogen; two grains of gas give onehundred thousand calories. Oxygen has not been prepared in anycommercial quantity in the atomic state. From watching that man's torch,from the color of the flame and other indications, I gather that he usesa flame of atomic oxygen-atomic hydrogen for melting, and surrounds itwith a preheating jacket of atomic hydrogen. The center flame probablydevelops a temperature of some 4000 deg. centigrade, and will naturally makethat tungsten alloy run like water.

  "As to the machine here--it is, as I said, a machine which impressesvery high frequencies on the body it is connected with. This puts themolecules in vibration at a frequency approaching that of light, andwhen the light impinges upon it, it can pass through readily. You knowthat metals transmit light for short distances, but in order that thelight pass, the molecules of metal must be set in harmonic vibration ata rate approaching the frequency of light. If we can impress such avibration on a piece of matter, it will then transmit light very freely.If we impress this vibration on the matter, say the body, electrically,we get the same effect and the body becomes perfectly transparent. Now,since it is the vibration of the molecules that makes the light passthrough the material, it must be stopped if we wish to see the machine.Obviously it is much easier to detect me here among solid surroundings,than in the plane high in the sky. What chance has one to detect amachine that is perfectly transparent when there is nothing butperfectly transparent air around it? It is a curious property of thisvibrational system of invisibility that the index of refraction is madevery low. It is not the same as that of air, but the difference is soslight that it is practically within the limits of observation error; sosmall is the difference that there is no 'rainbow' effect. Thedifference of temperature of the air would give equal effect.

  "Now, since this vibration is induced by radio impulse, is it notpossible to impress another, opposing radio impulse, that will overcomethis tendency and bring the invisible object into the field of thevisible once more? It is; and this machine on the table is designed todo exactly that. It is practically a beam radio set, projecting a beamof a wavelength that alone would tend to produce invisibility. But inthis case it will make me visible. I'm going to stand right here, andBob can operate that set."

  Arcot strode to the middle of the room, and then Morey turned thereflector of the beam set on him. There was a low snap as Arcot turnedon his set, then he was gone, as suddenly as the coming of darkness whena lamp is extinguished. He was there one moment, then they were staringat the chair behind him, knowing that the man was standing between themand it and knowing that they were looking through his body. It gave thema strange feeling, an uncomfortable tingling along the spine. Then thevoice--it seemed to come from the air, or some disembodied ghost as theinvisible man called to Morey.

  "All right, Bob, turn her on slowly."

  There was another snap as the switch of the disrupter beam was turnedon. At once there was a noticeable fogginess in the air where Arcot hadbeen. As more and more power was turned into the machine, they saw theman materialize out of thin air. First he was a mere shadowy outlinethat was never fully above the level of conscious vision. Then slowlythe outlines of the objects behind became dimmer and dimmer, as the bodyof the man was slowly darkened, till at last there was only a waveringaura about him. With a snap Morey shut off his machine and Arcot wasgone again. A second snap and he was solid before them. He had shut offhis apparatus too.

  "You can see now how we intend to locate our invisible pirate. Of coursewe will depend on directional radio disturbance locating devices todetermine the direction for the invisibility disrupter ray. But you areprobably marvelling at the greatness of the genius who can design andconstruct this apparatus all in one day. I will explain the miracle. Ihave been working on short wave phenomena for some time. In fact, I hadactually made an invisibility machine, as Morey will testify, but Irealized that it had no commercial benefits, so I didn't experiment withit beyond the laboratory stunt stage. I published some of the theory inthe Journal of the International Physical Society--and I wouldn't besurprised to learn that the pirate based his discovery on my report.

  "I am still working on a somewhat different piece of apparatus that Ibelieve we will find very relevant to this business. I'll ask you toadjourn after tonight's meeting for another twenty-four hours till I canfinish the apparatus I am working on. It is very important that you behere, Fuller. I am going to need you in the work to follow. It will beanother problem of design if this works out, as I hope it will."

  "I'll certainly make every effort to be here, Arcot," Fuller assuredhim.

  "I can promise you a tough problem as well as an interesting one." Arcotsmiled. "If the thing works, as I expect it to, you'll have a job thatwill certainly be a feather for your cap. Also it will be a change."

  "Well, with that inducement, I'll certainly be here. But I think thatpirate could give us some hints on design. How does he get his gliderten miles up? They've done some high-altitude gliding already. Thedistance record took someone across the Atlantic in 2009, didn't it? Butit seems that ten miles straight up is a bit too steep for a glider.There are no vertical air currents at that height."

  "I meant to say that his machine is not a true glider, but asemi-glider. He probably goes up ten miles or more with the aid of asmall engine, one so small it probably takes him half a day to getthere. And it would be easy for a plane to pass through the lowertraffic lanes, then, being invisible, mount high and wait for the airliner. He can't use a very large engine, for it would drag him down, butone of the new hundred horsepower jobs would weigh only about fiftypounds. I think we can draw a pretty good picture of his plane fromscientific logic. It probably has a tremendous wingspread and a veryhigh angle of incidence
to make it possible to glide at that height, andthe engine and prop will be almost laughably small."

  * * * * *

  The next evening the men got together for dinner, and there wasconsiderable speculation as to the nature of the discovery that Arcotwas going to announce, for even his father had no knowledge of what itwas. The two men worked in separate laboratories, except when either hada particularly difficult problem that might be solved by the other. Allknew that the new development lay in the field of short wave research,but they could not find out in what way it concerned the problem inhand.

  At last the meal was over, and Arcot was ready to demonstrate.

  "Dad, I believe that you have been trying to develop a successful solarengine. One that could be placed in the wings of a plane to generatepower from the light falling on that surface. In all solar engines whatis the greatest problem to be solved?"

  "Well, the more I investigate the thing, the more I wonder which is thegreatest. There are a surprising number of annoying problems to be met.I should say, though, that the one big trouble with all solar engines,eliminating the obvious restriction that they decidedly aren'tdependable for night work, is the difficulty of getting an area toabsorb the energy. If I could get enough area, I could use a very lowefficiency and still have cheap power, for the power is absolutely free.The area problem is the greatest difficulty, no doubt."

  "Well," Arcot junior said quietly, "I think you have a fairly good areato use, if you can only harness the energy it absorbs. I have reallydeveloped a very efficient solar engine. The engine itself requires noabsorbing area, as I want to use it; it takes advantage of the fact thatthe Earth is absorbing quintillions of horsepower. I have merely tappedthe power that the Earth has already absorbed for me. Come here."

  He led the way down the corridor to his laboratory, and switched on thelights. On the main laboratory bench was set up a complicated apparatusof many tubes and heavy bus bar connectors. From the final tube two thinwires ran to a long tubular coil. To the left of this coil was a largerelay switch, and a rheostat control.

  "Turn on the relay, Dad, then slowly rotate the controller to the left.And remember that it is rather powerful; I know this doesn't look like asolar engine, and nine o'clock at night seems a peculiar hour todemonstrate such a thing, but I'll guarantee results--probably more thanyou expect."

  Dr. Arcot stepped up to the controls and closed the switch. The lightsdimmed a bit, but immediately brightened again, and from the other endof the room came a low, steady hum as the big transformer took up theload.

  "Well, from the sound of that ten K.W. transformer there, if this engineis very efficient we ought to get a terrific amount of power out of it."Dr. Arcot was smiling amusedly at his son. "I can't very well controlthis except by standing directly in front of it, but I suppose you knowwhat you're doing."

  "Oh, this is a laboratory model, and I haven't gotten the thing intoshape really. Look at the conductors that lead to the coil; theycertainly aren't carrying ten K.W."

  Dr. Arcot slowly rotated the rheostat. There was a faint hum from thecoil; then it was gone. There seemed to be no other result. He rotatedit a bit more; a slight draught sprang up within the room. He waited,but when nothing more startling occurred, he gave the rheostat a sharpturn. This time there was absolutely no doubt as to the result. Therewas a roar like a fifty-foot wind tunnel, and a mighty blast of cold airswept out of that coil like a six-inch model of a Kansas cyclone. Everyloose piece of paper in the laboratory came suddenly alive and whirledmadly before the blast of air that had suddenly leaped out. Dr. Arcotwas forced back as by a giant hand; in his backward motion his hand waslifted from the relay switch, and with a thud the circuit opened. In aninstant the roar of sound was cut off, and only a soft whisper of airtold of the furious blast that had been there a moment before.

  The astonished physicist came forward and looked at the device a momentin silence, while each of the other men watched him. Finally he turnedto his son, who was smiling at him with a twinkle in his eye.

  "Dick, I think you have 'loaded the dice' in a way that is even morelucrative than any other method ever invented! If the principle of thismachine is what I think it is, you have certainly solved the secret of asufficiently absorbing area for a solar engine."

  "Well," remarked the elderly Morey, shivering a bit in the chill air ofthe room, "loaded dice have long been noted for their ability to makemoney, but I don't see how that explains that working model of an Arctictornado. _Burr_ it's still too cold in here. I think he'll needconsiderable area for heat absorption from the sun, for that enginecertainly does cool things down! What's the secret?"

  "The principle is easy enough, but I had considerable difficulty withthe application. I think it is going to be rather important though--"

  "Rather important," broke in the inventor's father, with a rare displayof excitement. "It will be considerably more than that. It's the biggestthing since the electric dynamo! It puts airplanes in the junk heap! Itmeans a new era in power generation. Why, we'll never have to worryabout power! It will make interplanetary travel not only possible, butcommercially economical."

  Arcot junior grinned broadly. "Dad seems to think the machine haspossibilities! Seriously, I believe it will antiquate all types ofairplanes, prop or jet. It's a direct utilization of the energy that thesun is kindly supplying. For a good many years now men have been tryingto find out how to control the energy of atoms for air travel, or torelease the energy of the constitution of matter.

  "But why do it at all? The sun is doing it already, and on a scale sogargantuan that we could never hope nor desire to approach it. Threemillion tons of matter go into that colossal furnace every second oftime, and out of that comes two and a half decillion ergs of energy.With a total of two and a half million billion billion billions of ergsto draw on, man will have nothing to worry about for a good many yearsto come! That represents a flood of power vaster than man couldcomprehend. Why try to release any more energy? We have more than we canuse; we may as well tap that vast ocean of power.

  "There is one thing that prevents us getting it out, the law ofprobability. That's why Dad mentioned loaded dice, for dice, as youknow, are the classical example of probability when they aren't loaded.Once they are loaded, the law still holds, but the conditions are now sochanged that it will make the problem quite different."

  Arcot paused, frowning, then resumed half apologetically, "Excuse thelecture--but I don't know how else to get the thought across. You arefamiliar with the conditions in a liter of helium gas in a container--atremendous number of molecules, each dashing along at several miles asecond, and an equal number dashing in the opposite direction at anequal speed. They are so thickly packed in there, that none of them cango very far before it runs into another molecule and bounces off in anew direction. How good is the chance that all the molecules shouldhappen to move in the same direction at the same time? One of the oldphysicists of Einstein's time, a man named Eddington, expressed it verywell:

  'If an army of monkeys were playing on typewriters they might write all the books in the British Museum. The chance of their doing so is decidedly more favorable than the chance that all the molecules in a liter of gas should move in the same direction at the same time.'

  The very improbability of this chance is the thing that is making ourproblem appear impossible.

  "But similarly it would be improbable--impossible according to the lawof chance--to throw a string of aces indefinitely. It isimpossible--unless some other force influences the happening. If thedice have bits of iridium stuck under the six spots, they will throwaces. Chance makes it impossible to have all the molecules of gas movein the same direction at the same time--unless we stack the chances. Ifwe can find some way to influence them, they may do so.

  "What would happen to a metal bar if all the molecules in it decided tomove in the same direction at the same time? Their heat motion isnormally carrying them about at a rate of several
miles a second, and ifnow we have them all go in one way, the entire bar must move in thatdirection, and it will start off at a velocity as great as the velocityof the individual molecules. But now, if we attach the bar to a heavycar, it will try to start off, but will be forced to drag the car withit, and so will not be able to have its molecules moving at the samerate. They will be slowed down in starting the mass of the car. Butslowly moving molecules have a definite physical significance. Moleculesmove because of temperature, and lack of motion means lack of heat.These molecules that have been slowed down are then cold; they willabsorb heat from the air about them, and since the molecule of hydrogengas at room temperature is moving at about seven miles a second, whenthe molecules of the confined gas in our car, or the molecules of themetal bar are slowed down to but a few hundred miles an hour, theirtemperature drops to some hundreds of degrees below zero, and theyabsorb energy very rapidly, for the greater the difference intemperature, the greater the rate of heat absorption.

  "I believe we will be able to accelerate the car rapidly to a speed ofseveral miles a second at very high altitudes, and as we will be able touse a perfectly enclosed streamlined car, we should get tremendousspeeds. We'll need no wings, of course, for with a small unit pointedvertically, we'll be able to support the car in the air. It will makepossible a machine that will be able to fly in reverse and so come to aquick stop. It will steer us or it will supply us with electrical power,for we merely have to put a series of small metal bars about thecircumference of the generator, and get a tremendously powerful engine.

  "For our present need, it means a tremendously powerful engine--and onethat we can make invisible.

  "I believe you can guess the source of that breeze we had there? Itwould make a wonderful air-conditioning unit."

  "Dick Arcot," began Morey, his voice tight with suppressed excitement,"I would like to be able to use this invention. I know enough of theeconomics of the thing, if not its science, to know that the apparatusbefore us is absolutely invaluable. I couldn't afford to buy the rightson it, but I want to use it if you'll let me. It means a new era intranscontinental air travel!"

  He turned sharply to Fuller. "Fuller, I want you to help Arcot with theship to chase the Pirate. You'll get the contract to design the newairliners. Hang the cost. It'll run into billions--but there will be nomore fuel bills, no oil bills, and the cost of operation will benegligible. Nothing but the Arcot short wave tubes to buy--and each onegood for twenty-five thousand hours service!"

  "You'll get the rights on this if you want them, of course," said Arcotquietly. "You're maintaining these laboratories for me, and your sonhelped me work it out. But if Fuller can move over here tomorrow, itwill help things a lot. Also I'd like to have some of your bestmechanics to make the necessary machines, and to start the power units."

  "It's done," Morey snapped.