Astounding Stories of Super-Science, August 1930

by Various

  The Flying City

  _By H. Thompson Rich_

  The ray shot down--and squadrons of planes frizzledlike moths in the air.]

  [Sidenote: From Space came Cor's disc-city of Vada--its mighty,age-old engines weakening--its horde of dwarfs hungry for the Earth!]

  In the burning solitude of the great Arizona desert, some two milessouth of Ajo, a young scientist was about to perform an experimentthat might have far-reaching results for humanity.

  The scientist was Gordon Kendrick--a tall, tanned, robust chap wholooked more like a prospector in search of gold than a professor ofphysics from the State University of Tucson.

  Indeed, he was in a way, a prospector, since it was gold hesought--some practical method of tapping the vast radio-energetictreasure of the sun--and it was an apparatus designed to accomplishjust this that he was about to test.

  The primary unit of the mechanism comprised a spheroidal vacuum-tubemeasuring a little over a foot across its long axis, mounted in asteel bracket that held it horizontal with the ground. Down throughits short axis ran a shaft on which was centered a light cross ofaluminum wire, carrying four vanes of mica, one face of each coatedwith lampblack. A flexible cable led from the bottom of this shaft tothe base of the bracket, where it was geared to a small electric motordriven by two dry cells. A rheostat-switch for delivering andcontrolling the current was mounted nearby.

  At the wide arc of the egg-shaped tube was a concave platinum cathode,at the narrow arc a nib of some sort, ending in a socket. From thissocket, two heavy insulated wires extended sixty feet or so across thesand to the secondary unit of the mechanism, which was roughly aseries of resistance coils, resembling those in an ordinary electricheater.

  * * * * *

  As Kendrick prepared to test this delicate apparatus that representedso much of his time and thought, held so much of his hope locked up init, a turmoil was in his heart, though his brown face was calm.

  If his theories were right, that revolving cross would tap and drawinto its vanes radio-energetic waves of force, much as the whirlingarmature of a dynamo draws into its coils electro-magnetic waves offorce. For the blackened sides of the vanes, absorbing more radiationthan the bright sides, would cause the molecules to rebound from thewarmer surfaces with greater velocity, setting up an alternatepressure and bringing the rays to a focus on the cathode, where theywould be reflected to the nib as waves of _heatricity_, to use theword he had coined.

  Those were Kendrick's theories, and now he moved to put them to thesupreme test. Switching on the current, he set the motor going. Inresponse, the cross began to revolve, slowly at first--then faster,faster, as he opened the rheostat wider.

  Eyes fixed on his resistance coils, he gave a sudden cry of triumph.Yes, there was no doubt about it! They were growing red, glowingbrightly, whitely, above the intense desert sunlight.

  Here was a means of convening solar radiation into heat, then, thatoffered tremendous commercial possibilities!

  But even as he exulted, there came a blinding flash--and the overtaxedcoils burst into flame.

  * * * * *

  Shielding his eyes from the glare, he reached for the rheostat, shutoff the current, rushed to his secondary unit--where he beheld anamazing sight. Not only had this part of the apparatus completelydisintegrated, but the sand of the desert floor under it as well. Onthe spot quivered a miniature lake of molten glass!

  As Kendrick stood ruefully beside that fiery pool, meditating on thespectacular but not altogether gratifying results of his experiment, apeculiar low humming sound reached his ears. Rushing back to hisprimary unit, with the thought that perhaps by some chance he had notfully closed the rheostat, he looked at the cross. But no, the vaneswere still.

  The humming increased, however--grew into a vibration that made hiseardrums ache.

  Puzzled, he looked around. What on earth could it be? Had his unrulyexperiment called into play some tremendous, unsuspected force of theuniverse. Was he to bring the world to ruin, as a result of his blindgroping after this new giant of power?

  Such predictions had often been made by the ignorant, to be dismissedby scientists as the veriest nonsense. But was there some truth in theuniversal fear, after all? Was he to be the Prometheus who stole firefrom Olympus, the Samson who toppled down the temple?

  Chilled, dizzied with the pain of the ever-increasing vibration, hegritted his teeth, awaiting he knew not what.

  Then it came--a spectacle so staggering that he went rigid with awe ashe regarded it, all power of motion utterly numbed for the moment. Thevibration ceased. The thing appeared.

  It was a city--a city in the air--a flying city!

  * * * * *

  As Kendrick stood staring at this phenomenon, he could scarcely credithis senses.

  Had the magic carpet of Bagdad suddenly materialized before him, hewould not have been more astounded. And indeed, it was in a way amagic carpet--a great disclike affair, several miles in diameter, itsmyriad towers and spires glinting like gold under the noonday sun,while its vast shadow fell athwart the desert like the pall of aneclipse.

  The lower portion, he noted, was in the main flat, though a number ofwartish protuberances jutted down from it, ejecting a pale violetemanation. Whatever this was it seemed to have the effect of holdingthe thing motionless in the air, for it hovered there quite easily, ahundred yards or so above the ground.

  But what was it? Where was it from? What had brought it?

  Those were the questions he wanted answered; and they were to be,sooner than he knew.

  As he stood there speculating, a device like a trap-door opened in thebase of the disc, and creatures resembling human beings begandescending. Began floating down, rather.

  Whereupon Kendrick did what any sensible man would have done, undersimilar circumstances. He reacted into motion. In short, he ran.

  * * * * *

  Glancing back over his shoulder after a minute or two, however, hedrew up sheepishly. Of that strange apparition and those who haddescended from it there was not a trace, not a shadow!

  But the peculiar humming had recommenced, he realized in the nextbreath--and at the same instant he felt himself seized by invisiblehands.

  There was a struggle, but it was brief and futile. When it was overhis captors became visible once more. They were singular little beingsabout four feet tall, with strange, wise, leathery faces, their headsgrotesquely bald.

  The humming had ceased again. The disc, too, was once more visible.

  What happened next was something even more astounding, if there couldbe any further degrees of wonder possible for the utterly baffledyoung scientist. He felt himself lifted up, leaving the desert floor,whirling away toward that incredible phenomenon hovering there.

  Another moment or two and he had been borne up through its trap-dooropening, was standing in a dark space bounded by solid metal walls.Then he was thrust into a cylinder with several of his tiny guards,shot swiftly upward.

  * * * * *

  A door opened as they came to rest, and he was led out into a vastcourt of gleaming amber crystal. Something like a taxi slid up, withirridescent planes, and he was bundled into it, whirled away again.

  Down broad, gleaming avenues they passed, where similar traffic floweddensely, but under marvelous control. Towering skyscrapers loomed toright and left. Tier on tier of upper and lower boulevards revealedthemselves, all crowded with automotive and pedestrian activity.

  At length a stupendous concourse was reached. Thousands of these taxisand similar vehicles were parked along its broad flanks, while literalswarms of diminutive individuals circulated to and fro.

  Assisted from the vehicle that had brought him to this obvious centerof the disc's activities. Kendrick was led into a monumental structureof jade-green stone that towered a full hundred, stories above thestreet level. There he was escort
ed into another of thoseprojectilelike elevators, shot up, up--till at length it came to rest.The door opened and he was led out into a small lobby of the sameamber crystal he had observed before.

  By now his guards had diminished to two, but he no longer made anyeffort to escape. Wherever this amazing adventure might lead, he wasresolved to follow it through.

  One of the guards had advanced to a jewelled door and was pressing abutton. In response, the door opened. A golden-robed, regal creaturestood there.

  * * * * *

  Though dwarfed to four feet, like his fellow, he was obviously theirmental superior to a prodigious degree. Not only was his symmetricalbald head of large brain content, but the finely-cut features of hisparchment face bore the unmistakable stamp of a powerful intellect.

  "_Ao-chaa!_" commanded this evident monarch of the disc, addressingthe guards.

  They bowed and departed, abruptly.

  "My dear Kendrick!" the regal personage now said, in thin, preciseEnglish. "It is indeed a pleasure to welcome you to my humblequarters. Pray enter and make yourself comfortable."

  Whereupon he ushered him into a dazzling apartment that was one vastmosaic of precious gems, indicated a richly carved chair, into whichthe young scientist dropped wonderingly.

  "Now then, Professor," continued the mighty little dwarf, when he wasseated in a chair even more sumptuous, "suppose we have a friendlylittle discussion. I have been much interested in your experiments onheat radiation. What you demonstrated this morning, in particular, wasmost absorbing. You have hit upon a rather profound scientificprinciple, yes?"

  "Possibly," Kendrick admitted, quite conscious that he was beingpatronized.

  "Oh, don't be modest, my dear fellow!" smiled the dwarf. "I am thelast one to belittle your achievement. Indeed, it is because of itthat I have invited you here to-day. Permit me to introduce myself,and to make clear one or two possibly perplexing matters. Then I amsure we shall have a most agreeable chat."

  * * * * *

  His name was Cor, he said, and he was in truth the monarch of thisstrange realm. His people had come from the one-time planet of Vada,far distant in the universe. A thousand years ago, this planet hadbeen doomed by the approach of an alien star. Their great scientist,Ravv, had met the emergency by inventing the disc, into whoseconstruction they had poured all their resources. The pick of theirpopulace had been salvaged on this giant life-raft. The rest hadperished when that destroying star had crashed down on the doomedVada.

  Since then these survivors and their descendants had been voyagingthrough space on their marvelous disc. For hundreds of years they hadgiven no thought to the future, content to drift on and on in theinterstellar void, breathing an atmosphere produced artificially. Butat length the inevitable had happened. This superb piece of mechanismdevised by their super-genius, Ravv, was beginning to show signs ofwear. Some of its mighty engines were nearing the exhaustion point.Either they must soon find a planet comparable with the one they hadonce known, where they could pause and rehabilitate their machinery,or they must disintegrate and pass into oblivion.

  Faced with that crisis, Cor had long been seeking such a planet. Hehad found it, at last, in the earth--and had resolved that this waswhere they were going to alight and transplant the civilization ofancient Vada, pending such time as they could take to space again.

  * * * * *

  For some months now they had been hovering over various portions ofthe earth, studying its geography and its peoples, with the resultthat they had concluded the United States offered the most logicalpoint for launching the attack. Once this country was subdued, theywere in possession of the richest and most advanced section of theplanet. The conquest of the rest of it could await their leisure.

  With such an invasion in view, their scientists had mastered thelanguage of the country. This had been accomplished very easily, sincein addition to their power of mingling with the populace in aninvisible form, they had the principles of radio developed to a highdegree and were able to tune in on any station they wanted.

  Kendrick sat there, stunned, as Cor followed his astounding revelationof their origin with this calm plan for the conquest of America, ofthe world. Why, of all people on earth, had he alone been singled outfor this disclosure?

  He asked the question now.

  "My dear Professor, can't you really guess?" replied Cor, with thatleathery smile. "Hasn't it dawned that you were a little too near ourown field with that machine of yours? A trifle more research, aslightly different application--and you would have become a dangerousenemy."

  "You--you mean--?"

  "I mean there isn't a great deal of difference between the experimentsyou have been making and those our great Ravv once made. For instance,had you broadcast your heatricity, as you call it, instead of tryingto transmit it on wires--well, picture a receiving apparatus in eachhome of the land, like your commercial radio sets. You would havebecome a billionaire, don't you see?"

  * * * * *

  Kendrick saw indeed. It was simple, so simple! Fool--why hadn't hethought of it?

  "But your invention will never make you wealthy now, my dear fellow,"Cor went on, tauntingly. "You will be our guest, here, until we havetaken over your interesting country. After that, if there is any needfor the broadcasting of heat, we will furnish it ourselves. We havethose facilities, among others, fully developed. Would you care to seeour plant?"

  Kendrick naturally admitted that he would, so the dwarf led himthrough a rear door and up a winding flight of stairs. They emergedpresently into a great laboratory housed in the glass-roofed pinnacleof the tower.

  There he beheld a sight that left him breathless. Never before had heseen such an assemblage of scientific apparatus. Its vastness andstrangeness were fairly overpowering, even to a man as well versed inphysio-chemical paraphernalia as he was.

  Before his eyes could take in a tenth part of the spectacle, Cor hadled him to the left wall.

  "There," he said, "you will observe a development of your heatgenerator."

  Kendrick looked--to see a long bank of large vacuum-tubes, each aboutthree feet high and a foot wide, connected by a central shaft thatcaused series of little vanes in each of them to revolve at lightningspeed.

  Around the apparatus moved numerous small attendants, oiling, wiping,adjusting its many delicate parts.

  "Well, what do you think now?" asked Cor.

  Kendrick made no reply, though he was thinking plenty.

  "You see, it is your invention, my dear Professor," the dwarf went onin his taunting voice, "only anteceded by a thousand years--and rathermore perfected, you must admit."

  * * * * *

  He walked now to the center of the laboratory, where stood a huge dialof white crystal, ranked with many levers and switches, all cappedwith the same material.

  "Behold!" he said, throwing over one.

  Instantly there came again that peculiar low humming that had sopuzzled him a few minutes before--and the entire room, its engines,its attendants, Cor himself, leapt into invisibility. Only Kendrickremained, facing the faintly visible crystal dial.

  Then he saw a switch move, as though automatically. But no, for thedwarf's hand was on it now. Visibility had returned. The vibrationceased.

  "That is the central control," said Cor. "Our city and all itsinhabitants become invisible when that switch is thrown. Only the dialremains, for the guidance of the operator, and even that cannot beseen at a distance of more than fifty feet. But now behold!"

  He raised his hand, touched a watch-like device strapped to hiswrist--and was instantly invisible. But the laboratory and everymachine and person in it remained in plain view. Nor was there anyvibration now.

  * * * * *

  The next moment, having touched that curious little device again, Correappeared.

  "That is the local c
ontrol," he said. "Every one of our inhabitants,except those under discipline, has one of these little mechanisms. Itenables us to make ourselves invisible at will. A convenience attimes, you must admit."

  "Decidedly," Kendrick agreed. "And the principle?"

  "Quite simple. One of those, in fact, that lies behind yourresearches. Doubtless you would have hit upon it yourself in time.Your own scientist, Faraday, you may recall, held the opinion that thevarious forms under which the forces of matter manifest themselveshave a common origin. We of the disc, thanks to our great Ravv, havefound that common origin."

  It was the origin of matter itself, Cor said, which lay in the etherof interstellar space--energy, raw, cosmic--vibrations, rays.

  By harnessing and controlling these various rays, his people had beenable to accomplish their seeming miracles--miracles that the people ofearth, too, were beginning to achieve--as in electricity, forinstance, and its further application, radio.

  But the people of Vada had long since mastered such simple rays, andnow, in possession of vastly more powerful ones, had the elementalforces of the universe at their disposal.

  * * * * *

  The disc was propelled through space by short rays of tremendouslyhigh frequency, up above the ultra-violet. The same rays, directeddownward instead of outward, enabled them to overcome the pull ofgravity when in a planet's influence, as at present. And the escalatorrays, by which they could proceed to and from the disc, were also ofhigh frequency, as were their invisibility rays.

  "But you, Professor, are more interested in low frequency rays, thelong ones down below infra-red," continued Cor. "You have seen ourdevelopment of the heat-dynamo principle. It utilizes, I might add,not only solar radiation but that of the stars as well. There being abillion and a half of these in the universe, many of them a thousandtimes or more as large as your own sun, we naturally have quite anefficient little heating plant here. It provides us with our weapon ofwarfare, as well as keeping us warm. Permit me to demonstrate."

  He led the way to a gleaming circle of glass like an invertedtelescope, about a yard in diameter, mounted in the floor.

  "Look!" said the dwarf.

  Kendrick did so--and there, spread below him, lay the floor of thedesert. His camp, his apparatus, were just as he had left them.

  Cor now moved toward the dial.

  "Behold!" he said, pulling a lever.

  Instantly the scene below was an inferno. Stricken by a blast ofstupendous heat, the whole area went molten, lay quivering like a lakeof lava in the crater of an active volcano.

  "Suppose, my dear Professor," smiled the dwarf, strolling back fromthe dial, "just suppose, for instance, that instead of the lonelycamp of an obscure scientist, your proud city of New York had beenbelow there!"

  * * * * *

  Kendrick shuddered.

  Well he knew now the terrible power, the appalling menace of thisstrange invader.

  "I would prefer not to make such a supposition," he said, quietly,with a last thoughtful glance at that witches' caldron below.

  "Then let us think of pleasanter things. You are my guest of honor,sir--America's foremost scientist, though she may never realize it,"with a piping chuckle. "To-night there will be a great banquet in yourhonor. Meanwhile, suppose I show you to your quarters."

  Nettled, fuming, though outwardly calm, Kendrick permitted himself tobe escorted from the laboratory to an ornate apartment on one of thelower floors.

  There Cor left him, with the polite hint that he would find plenty ofattendants handy should he require anything.

  Alone now, in the midst of this vast, nightmarish metropolis, he pacedback and forth, back and forth--knowing the hideous fate thatthreatened the world but powerless to issue one word of warning, muchless avert it.

  * * * * *

  Kendrick was still thinking and brooding along these lines when he sawthe door of the apartment swiftly open and close again.

  Someone had entered, invisible!

  Backing away, he waited, tense. Then, suddenly, his visitormaterialized. With a gasp, he saw standing before him a beautifulgirl.

  She was a young woman, rather, in her early twenties. Not one of thesepigmies of the disc either, but a tall, slender creature of his ownworld.

  Her hair was dark, modishly bobbed. Her eyes were a deep, clear brown,her skin a warm olive. And she was dressed as though she had juststepped off Fifth Avenue--which indeed she had, not so long ago, ashe was soon to learn.

  "I hope I haven't startled you too much, Mr. Kendrick," she said, in arich, husky murmur, "but--well, there wasn't any other way."

  "Oh, I guess I'll get over it," he replied with a smile. "But you havethe advantage of me, since you know my name."

  Hers was Marjorie Blake, she told him then.

  "Not the daughter of Henderson Blake?" he gasped.

  "Yes," with a tremor, "his only daughter."

  Whereupon Kendrick knew the solution of a mystery that had baffled thepolice for weeks. The newspapers had been full of it at the time. Thisbeautiful girl, whose father was one of America's richest men andpresident of its largest bank, had disappeared as though the earth hadswallowed her. She had left their summer estate at Great Neck, LongIsland, on a bright June morning, bound for New York on a shoppingtour--and had simply vanished.

  * * * * *

  Suicide had been hinted by some of the papers, but had not been takenseriously, since she had no apparent motive for ending her life.Abduction seemed to be the more logical explanation, and huge rewardshad been offered by her frantic parents--all to no avail.

  What had happened was, she now explained, that after visiting severalshops and making a number of purchases, she had stepped into CentralPark at the Plaza for a breath of fresh air before lunching at theSherry-Netherlands, where she planned to meet some friends.

  But before advancing a hundred yards along the secluded path, she hadbeen seized by invisible hands--had felt something strapped to herwrist, before anyone came in sight--and then, invisible too, had beenlifted up, whirled away into a vast, humming vibration that soundedthrough the air.

  Once on the disc, it had swept off into space at incredible speed,pausing only when some hundreds of miles above the earth and invisiblefrom below without mechanical aid. When its vibration finally ceasedthat amazing city had leapt before her eyes.

  Then, her own visibility restored, she had been led into the presenceof that mighty little monarch, Cor, who explained that she had beenseized as a hostage and would be held as an ace in the hole, pendingconquest of her country. Since when she had been a prisoner aboard thedisc.

  * * * * *

  Learning of Kendrick's capture, from gossip among the women, she hadtaken the first opportunity of coming to him, in the hope that betweenthem they might devise some means of escape.

  Indeed, that was his own fondest hope--their imperative need, if thepeople of America and of the earth were to be saved from thisappalling menace. But what basis was there for such a fantastic hope?Just one, that he could see.

  "That thing on your wrist," he said, voicing it. "I'm surprised theylet you wear one of those."

  "They don't," she smiled. "I stole it!--from one of the maids in myapartment. It was the only way I could get here without being seen. Ifelt I must see you at once. We've got to do something, soon, or it'llbe too late. I felt that, as a scientist, you might have some idea howwe could get off."

  "How do the people themselves get off?" he asked. "That escalatorray--do you know how they use it?"

  "No, I've never been able to find out. They don't let me go near thatpart of the city."

  Kendrick reflected a moment.

  "Let's have a look at that invisibility affair," he said.

  She removed it from her wrist, handed it to him. Somewhat in awe, heexamined it.

  * * * * *
/>
  The mechanism portion, which was linked in a strap of elastic metal,resembled only superficially a watch, he now saw. Rather it had theappearance of some delicate electric switch. Rectangular in shape, itwas divided into two halves by a band of white crystal. In each ofthese halves were two little buttons of the same material, those onone side round, on the other square.

  "Which buttons control the invisibility?" he asked.

  "The square ones," she replied. "One's pushed in now, you see. If youshould push the other, the first would come out--and you'd pass out ofthe picture, so to speak."

  Kendrick was half tempted to try the thing then and there, butdeferred the impulse.

  "What are the round buttons for?" he inquired instead.

  Marjorie didn't know, but thought they were probably an emergencypair, in case something went wrong with the square ones. In any event,nothing happened when you pushed them.

  Kendrick pushed one, just to see. It was true. Nothing happened--buthe seemed to sense a faint, peculiar vibration and a wave of giddinessswept over him. On pushing the other, which released the first, itstopped.

  * * * * *

  He handed the device back to Marjorie.

  "There's your bracelet. Now, if I can just get one like it, I thinkwe'll get down to earth all right."

  "Oh, Mr. Kendrick!" Her eyes lit up eagerly. "Then you've thought of away?"

  "Not exactly. I think I've discovered their own way. I can't becertain, but I'm willing to gamble on it, if you are."

  "Then you--you think those round buttons are connected with theescalator rays?"

  "Exactly! I think they control individual descent and ascent, just asthe square ones control individual visibility and invisibility. Atany rate, it's the hunch I'm going to act on right now, if you're withme."

  "Oh, I'm with, you!" she breathed. "Anything, death almost, would bepreferable to this."

  "Then stand by, invisible. I'm going to get one of my jailors in hereand relieve him of his wrist-watch."

  Marjorie touched that little square button on her own. She instantlybecame invisible.

  Kendrick touched a button too, a button he had noticed beside thedoor. As he had supposed, it brought one of the Vadans.

  Shutting the door quietly, he seized the fellow before he could movehis hand to his wrist. Thwarted in his attempt to vanish from sight,the diminutive guard attempted an outcry. But Kendrick promptlythrottled him.

  * * * * *

  Marjorie had reappeared by now and together they bound him to a chairwith a gilded cord torn from the drapery.

  Removing the precious mechanism from his wrist, Kendrick slipped it onhis own.

  "Now let's go!" he said, pressing the protruding square button of thedevice. "We haven't a minute to--my golly, what a peculiar sensation!"

  "It is rather odd, isn't it?" she laughed, pressing her own andjoining him in that invisible realm.

  "Feels like a combination electric massage and cold shower! Where areyou, anyway? I can't see you."

  "Of course you can't!" came an unseen tinkle. "Here!"

  He felt her brush him.

  "Better hold hands," he suggested, then gave an invisible flush he wasglad she couldn't see.

  "All right. A good idea."

  Her delicate hand came into his, soft, warm. Heart vibrating evenfaster than his body, his whole being a-quiver with a strangeexaltation, Kendrick opened the door, and they left the apartment.

  * * * * *

  The next half-hour was the tensest either of then had everexperienced. Every foot of the way was fraught with peril.

  Not only did they have to carefully avoid the visible swarms of littlepeople who hurried everywhere, but had to be on their guard as wellagainst any who might be moving about like themselves under cover ofinvisibility.

  Nor could they use any elevator or public conveyances, but wereobliged to make their way down to the concourse by heaven knew howmany flights of stairs, and cross heaven knew how many teeming streetson foot, before they reached the amber court, below which thetrap-door and their hope of freedom.

  They got there at last, however, descended, and peered down from thatyawning brink upon the desert floor--to draw back with gasps ofdismay. For the area still gleamed semi-molten from the stupendousblast that had wiped out Kendrick's camp.

  "W-what is it?" she gasped.

  Swiftly he told her.

  "But isn't there any way around it? Look, over there to the left. Oneedge of the crater seems to end almost underneath us."

  It was true that the center of the caldron was far to the right ofwhere they stood, and that its left rim was only a little within theirdirect line of descent. But to land even one foot inside that infernowould be as fatal as to alight in its very midst.

  * * * * *

  Kendrick was thinking fast.

  "There's just a chance," he said. "It all depends upon how wide thezone of these escalator rays is, and whether we can tune in on them.At least, I can probably answer the latter question."

  Pushing the protrudent round button on his mysterious bracelet as hespoke, he leaned over the edge of the trap-door and awaited results.

  They were not long in coming. The vibration he was already under fromthe invisibility rays seemed to double. Alternate waves of giddinessand depression, of push and pull, swept over him.

  A minute of it was enough. He pressed the round button that nowprotruded, ending this influence, and faced Marjorie, stating:

  "I'm positive now that these things control descent and ascent. Asnearly as I can figure, the rays work on the principle of an endlessbelt. If you're up here, you get carried down, and vice versa. As tohow wide the belt is, and whether you can move sideways on it, remainsto be seen. Anyway, I'm going to take a chance. I'll go first. If myguess is wrong, you--well, needn't follow."

  "No, I'm going with you!" she declared resolutely. "We've come thisfar together. I shan't be left alone now. Let's go!"

  And again her soft, warm hand was in his.

  Lord, what a girl! How many would be brave enough to take a gamblelike that, on a fellow's mere supposition?

  "All right--go it is!" he said. "Push your round button, like this."He showed her the way he thought was right, pushed his own. "Ready?"

  "Ready!"

  * * * * *

  Their voices were grave. It was a grim prospect, stepping off intospace like that, with only a guess between them and death.

  "Then jump!"

  They jumped, gripping each other's hands tightly--and instead ofdropping like plummets were caught in a powerful field of force andwhirled gently downward.

  "Oh, you were right!" gasped Marjorie, awed. "See, we--"

  Then she paused, horror-stricken, for it was obvious that they were todescend within that lake of molten glass, unless they could changetheir course at once.

  "Quick!" he called. "Hold fast! Now--run!"

  Breathless, they raced to the left, across that invisible descendingbelt.

  Too far, Kendrick knew, and they would plunge outside its zone, fallcrushed and mangled. Not far enough, and they would meet cremation. Itwas a fearful hazard, either way, but it had to be taken.

  They were almost down, now, and still not quite far enough to theleft. The heat of that yawning crater rose toward them.

  "Faster--_faster_!" he cried, fairly dragging her along with him.

  A last dash--a breathless instant--and they stood there on the ground,not three feet from the edge of doom.

  Swooning with the heat, Marjorie swayed against him, murmured anincoherent prayer.

  "Take heart!" he whispered, lifting her bodily and bearing her someyards away. "We're down--safe!"

  * * * * *

  Their safety was but relative, however, Kendrick well knew. Until theycould put miles between them and this monstrous disc, they were not
really safe. No telling how soon their escape might be discovered. Notelling what terrible means Cor might take of curbing their flight.

  So as soon as Marjorie had recovered sufficiently to proceed, theyheaded off across the desert at a fast walk toward Ajo, where he hopedto catch the afternoon train for Gila Bend. From there, they couldboard the limited for Tucson and points east, when it came throughfrom Yuma that night.

  They had tuned out on the escalator rays, but continued on stillinvisible--for the disc hung above them in plain view and it wouldhave been suicide to let themselves be seen.

  Even so, Kendrick soon began to have an uneasy feeling of beingfollowed. He looked around from time to time, but could see nothing.Were some of those invisible little creatures on their trail?

  He said nothing to Marjorie of his anxiety, but presently she toobegan glancing backward uneasily, every few steps.

  "They are near us!" she said at length, in a whisper. "I can sensethem."

  It was more than sense, they soon discovered. Little paddings becamequite audible, and once or twice they saw the sand scuffed up, nottwenty feet away, as though by a foot passing over it.

  * * * * *

  Meanwhile they were climbing a rise of ground, broken by many smallhummocks and dotted with thorny shrubs. On the other side, at the footof a long down-slope, lay Ajo.

  Once they reached the summit, Kendrick felt sure they couldoutdistance their pursuers on the descent. Already, if his watch wasright, the train was preparing to pull out. It would be a breathlessdash, but he was confident they could make it.

  So he reassured Marjorie as best he could, and helped her on up theslope.

  They were practically on the summit and already in view of the littlerailroad station and huddle of shacks below--when suddenly he felthimself tripped and flung violently to the ground. At the sameinstant, his companion emitted a scream, as she felt herself seized byinvisible hands.

  Leaping to his feet, Kendrick flailed out with solid fists at theirattackers. Groans answered the impacts and he knew his blows weretaking effect.

  * * * * *

  Free for a moment he dashed to Marjorie, felt for the midgets whoswarmed around her. Seizing one of the invisible forms, he lifted itand flung it crashing to the ground. Another, likewise, and another.

  Then he threshed his legs, where two of the creatures clung, trying todrag him down again. They flew through the air, with cries of fright.

  "Well, so far, so good!" he exclaimed. "We won't wait to see if thereare any more. Come on--let's go!"

  "Right!"

  Reaching for each other's hands, they raced down the slope.

  Halfway there they saw a warning blast of steam rise from the engine,followed by a whistle.

  "They'll be pulling out in a minute now!" he gasped, increasing speed."We've got to make it!--our only chance!"

  "We _will_ make it!" she sobbed through clenched teeth, meeting hispace.

  Glancing over his shoulder, after another fifteen seconds, Kendricksaw that the disc was no longer visible. Since there was no vibrationhe realized with relief that it was now hidden behind the slope theywere descending.

  "Quick--push your button!" he said, pushing his own.

  They came out of the influence of the invisibility rays, racedbreathless on down the slope--gained the station platform just as thetrain was getting under way.

  Helping the exhausted girl aboard, he mounted the steps himself, ledher through the vestibule into its single passenger coach.

  Dropping into a seat, they sat there panting as the train gatheredspeed.

  * * * * *

  By the time the decrepit but life-saving little local drew into GilaBend they had somewhat recovered from their harrowing experience.

  Marjorie was still pale, however, as Kendrick helped her from thetrain.

  "I may recover," she said with a wan smile, "but I'll never look thesame! An old saying, but I know what it means now."

  He thought better of a sudden impulse to tell her she looked quite allright to him. Instead, he said grimly:

  "I know now what a lot of things mean!"

  The Tucson limited would not be through for over an hour, theylearned. That would give them time to hunt up the authorities andsound a warning of the ominous invader that was in the vicinity.Perhaps, by prompt military action, it might be destroyed, or at leastcrippled.

  But first they went to the telegraph office, where Marjorie got off amessage that would bring joy to her grieved family.

  While standing there outside the barred window, odors of food waftingto them from a nearby lunch-room.

  "Um-m!" she sniffed. "That smells good to me! I haven't tasted anyearthly cooking for ages. Everything on that horrible disc wassynthetic."

  "Then I suggest we have ham and eggs, at once," he said. "Or would youprefer a steak?"

  "I think I'll have both!"

  * * * * *

  As they walked into the lunch-room, Kendrick told her of the banquetin his honor Cor had promised for that night.

  "I guess I didn't miss much," he ended.

  "You certainly didn't!" she assured him, with a smile. "It would haveopened with a puree of split-molecule soup, continued with an entreeof breaded electrons, and closed with an ionic cafe."

  He laughed.

  "I'm just as well satisfied. I was unable to attend! Humble as it is,I think this will prove to be much more wholesome food."

  Night had fallen by the time they left the lunch-room. Glancing at hiswatch, Kendrick saw that they still had better than a half-hour beforethe limited was due, so they betook themselves to the police station.

  It was only a block away and in consequence they weren't long reachingit.

  The chief had gone home, the officer at the desk informed them, but ifthere was anything they cared to report, he would be glad to make noteof it.

  A big raw-boned westerner, he shifted his quid as he spoke and spatresoundingly in a cuspidor at his feet.

  "All right, then--get your pencil ready!" said Kendrick with a smile."This is Miss Marjorie Blake, daughter of Henderson Blake, of NewYork. Perhaps you read of her disappearance, a few weeks ago. AndI...."

  As he introduced himself and told briefly of their astoundingexperience, the officer's eyes bulged with amazement.

  "Say, what yuh-all tryin' to hand me?" he snorted finally. "D'yuhthink I was born simple?"

  "Press your button!" whispered Marjorie. "Show him how theinvisibility ray works. It'll save a lot of argument."

  "Right!"

  * * * * *

  He held up his wrist.

  "See this? Now watch!"

  Whereupon he pressed the button. But to their dismay, nothinghappened.

  "Wa-al. I'm still watchin'!" drawled the officer. "Who's loony now?"

  Kendrick examined the mechanism in impatience, pressed that littlebutton repeatedly: but still nothing happened.

  "Try yours!" he told Marjorie finally.

  She did so, with similar results--or lack of them, rather.

  "Something's wrong," he said at length. "The ray isn't working."

  "Wrong is right!" declared the officer with a contemptuous flood oftobacco juice. "Yuh folks better go catch yuhr train 'fore yuh fergetwhere it is."

  Chagrined, embarrassed, they took their leave, headed back toward therailroad station.

  "Of all the utterly silly things!" declared Marjorie, as they walkedalong. "Why do you suppose it didn't work?"

  Kendrick didn't reply at once. When he did, his voice was grave.

  "Because the disc has gone!" he said. "We are outside its zone ofinfluence. That's my hunch, at least, and I think we'd better act onit."

  "You mean...?"

  "I mean our escape has probably caused them to hurry their plans.They're probably over New York right now. I think we'd better getthere the quickest possible way."r />
  * * * * *

  The result was that when the train came, they remained on it only toTucson. There they chartered a fast plane and started east at once.

  At sunset the following day the plane swooped out of the sky and slidto rest on the broad grounds of the Blake estate at Great Neck.

  As Kendrick stepped from the cabin and helped Marjorie down, a tall,distinguished-looking man with graying hair and close-cropped mustachecame hurrying toward them.

  "Daddy!" she cried, rushing into his arms. "Oh, Daddy--Daddy!"

  Even without this demonstration. Kendrick would have recognizedHenderson Blake from pictures he had seen recently in the papers.

  Now he was introduced, and Blake was gripping his hand warmly.

  "I don't quite know what this is all about, Professor," he heard thegreat financier say. "Marjorie's telegram last night was as cryptic asit was over-joying. But I do know that I owe you a deep debt ofgratitude."

  "Yes, and you owe our pilot about a thousand dollars, too!" put in thedaughter of the house, clinging to her father's arm. "Please give hima check--then we'll go inside and I'll explain all about it."

  "A matter very much easier dispatched than my debt to ProfessorKendrick," said Blake, complying.

  The check was for two thousand, not one, the pilot saw when hereceived it.

  "Thank you very much, sir!" he said, saluting.

  "Don't mention it. Good night--and good luck to you!"

  * * * * *

  The pilot returned to his plane, it lifted from the lawn, droned offinto the twilight.

  Then they approached the cool white villa that stood invitingly ahundred yards or so away beyond sunken gardens.

  As they neared it, a handsome, well-preserved woman whose facereflected Marjorie's own beauty came toward them. Lines of sufferingwere still evident around her sensitive mouth, but her dark eyes wereradiant.

  "Mother!"

  "My poor darling!"

  They rushed into each other's arms, clung, sobbing and laughing.

  Kendrick was glad when these intimate greetings were over and he hadmet Mrs. Blake.

  They were in the drawing-room now, listening to a somewhat more lucidaccount of their daughter's experiences and those of her rescuer.Marjorie was doing most of the talking, but every now and again shewould turn to Kendrick for verification.

  "Heavens!" gasped Mrs. Blake, finally. "Can such things be possible?"

  "Almost anything seems possible nowadays, my dear," her husband toldher. "And you say, Professor, that you have brought back samples ofthis invisibility device?"

  "Yes, we have, but I can't promise they'll work. I'll try, however."

  Whereupon, sceptically, he pressed that little square button--andinstantly faded out of sight.

  "Good Lord!" cried Blake, leaping to his feet. "That proves it! Why,this is positively--"

  * * * * *

  His remarks were cut short by a scream of terror from his wife.

  "Marjorie--Marjorie!" she shrieked.

  Wheeling, he faced the chair where his daughter had sat. It was empty,so far as human eyes could see.

  "Don't worry Mother--Daddy!" came a calm voice from it. "I'm quite allright--coming back--steady."

  And back she came, as did Kendrick, from the empty chair beside her.

  His face was grave. The success of the demonstration, which had provedtheir story to practical-minded Henderson Blake, had proved to himsomething altogether more significant. The disc, as he had surmised,had rushed eastward immediately on learning of their escape, and wasnow probably hovering right over New York.

  "Marvelous--marvelous!" declared Blake. "But that heat ray, Professor.That sounds bad. You are convinced it is as powerful as they makeout!"

  "Positively! That blast they let go in the desert would have utterlydestroyed New York."

  "Hm! Yes, no doubt you're right. I fully realize how the fearfulmenace of this thing. Do you think the military authorities will beable to cope with it?"

  "I don't know. Perhaps, if they are prompt enough."

  "And is there no other way--no scientific way?"

  * * * * *

  Kendrick grew thoughtful.

  "I wonder," he said at last. "There's just a possibility--somethingrunning through my mind--an experiment I'd like to make, if I had thefacilities of some large electrical laboratory."

  "You shall have them to-morrow!" Blake promised. "I'm one of thedirectors of Consolidated Electric. Their experimental laboratory inBrooklyn is the finest of its kind in America. I'll see that you havethe run of it."

  "That will be very kind," said Kendrick. "But don't expect anything tocome from it, necessarily. It's just a theory I want to work out."

  A butler entered at this moment and announced dinner.

  "Well, theories are mighty these days!" beamed Blake, as they rose,clapping the younger man on the shoulder. "You go ahead with yourtheories--and I'll bring a few facts to bear. To-morrow noon I'llescore some military men and others of my friends over to thelaboratory to hear and see something of this menace direct. Meanwhile,and during this crisis, it will honor me to have you as my guest."

  "Our guest!" amended Marjorie, with a warm smile.

  * * * * *

  Next morning Blake motored Kendrick out to the Brooklyn Laboratory ofthe Consolidated Electric Utilities Corporation and installed himthere.

  Then he left--to return at noon with the promised delegation ofgenerals, admirals, statesmen and financiers.

  They were all frankly sceptical, though realizing that Henderson Blakewas not a man given to exaggeration. Nor did their scepticismaltogether vanish when Kendrick had ended his bizarre story with ademonstration of the invisibility device.

  Murmurs of amazement ran around the laboratory, it is true, but themore hard-headed of his spectators charged him with having inventedthe apparatus himself. Though they didn't come right out and say so,they seemed to imply that he was seeking publicity.

  Annoyedly, Kendrick tried to refute their charges. But even as he wassummoning words, refutation utter and complete came from the air.

  A low, humming vibration sounded, grew in volume till it filled theroom--and as suddenly ceased: The light of midday faded to twilight.

  "_The disc!_" gasped Kendrick, rushing to the west windows.

  They followed, tense with awe. And there, between earth and sun, itsmyriad towers and spires refracting a weird radiance, hovered thatvast flying city.

  "My God!" muttered a famous general, staring as though he had seen aghost.

  A great statesman opened his lips, but no words came.

  "Appalling! Incredible!" burst from others of that stunned assemblage.

  * * * * *

  Their comments were cut short by a broadcast voice, thin and clear,tremendously amplified, a voice Kendrick recognized at once as that ofCor.

  "People of America!" it said. "We of the planet Vada have come toconquer your country. You will be given forty-eight hours to lay downyour arms. If complete surrender has not been made by high noon, twodays from now, New York will be destroyed."

  The voice ceased. The humming recommenced--waned in volume till itdied away. Twilight turned once more to midday.

  Peering fixedly through the west windows of the laboratory, the littleassemblage saw the disc swallowed up in the clear blue sky.

  Then they turned, faced one another gravely.

  Outside, on the streets, confusion reigned. In newspaper plants,presses were whirling. In telegraph and cable offices, keys wereticking. From radio towers, waves were speeding.

  Within an hour, the nation and the world knew of this planetaryinvader and its staggering ultimatum.

  Naturally, the government at Washington refused to meet these shamefulterms. Military and naval forces were rushed to the threatenedmetropolis. The Atlantic Fl
eet steamed up from Hampton Roads underforced draught and assembled in the outer harbor. Thousands of planesgathered at Mitchell Field and other nearby aerodromes.

  * * * * *

  But where was the enemy? He must be miles up in space, Kendrick knew,as he toiled feverishly in the laboratory over his experiment after asleepless night. For had that flying city been nearer earth, it couldnot have maintained invisibility without that peculiar hummingvibration.

  Scout planes urged on by impatient squadron commanders, climbed tillthey reached their ceilings, searching in vain. They could encounternothing, see nothing of the invader.

  Thus passed a morning of growing tension.

  But by noon of that day, with a bare twenty-four hours left beforethe expiration of the ultimatum, the disc came down, showed itselfboldly.

  There followed stunning disasters.

  One salvo, and the ray shot down--the Atlantic Fleet, the pride ofAmerica, burst and melted in flaming hell. Squadrons of planes,carrying tons of bombs, frizzled like moths in the air. Mightyprojectiles hurled by land batteries were deflected off on wildtrajectories.

  Appalled, the nation and the world followed in lurid extras thesecrushing defeats.

  By nightfall of that day, all seemed lost. All opposition had beenobliterated. America must capitulate or perish. It had until the nextnoon to decide which.

  * * * * *

  Meanwhile, in that great Brooklyn laboratory, Kendrick was workingagainst time, besieged by frantic delegations of the nation's leaders.They knew now that their one hope lay in him. Was he succeeding? Wasthere even any hope?

  Face haggard, eyes bloodshot from lack of sleep, he waved them away,went on with his work.

  "I will tell you--as soon as I know."

  That was all he would say.

  Followed a night that was the blackest in all history, though themyriad stars of heaven shone tauntingly brilliant in the summer sky.

  At length, as dawn was breaking. Kendrick paused in his labors.

  "There!" he said, grimly, surveying an apparatus that seemed toinvolve the entire facilities of the laboratory. "It is done! Nowthen--will it work?"

  The delegation were called to witness the test.

  Henderson Blake was among them, as was Marjorie. She stepped forward,as he prepared to make the demonstration.

  "I _know_, somehow, you're going to be successful!" she murmured,pressing his hand, meeting his eyes with a smile of confidence.

  "I hope you're right--Marjorie!" he replied, letting slip the lastword almost unconsciously.

  Her face colored warmly as the stepped back and rejoined her father.

  Kendrick's heart was beating fast as he turned to his instruments. Howcould he fail, with faith like that behind him?--love, even, perhaps!He mustn't fail--nor would he, if his theories were sound.

  * * * * *

  Addressing the assemblage, he explained briefly the complicatedapparatus.

  "These towers," he said, pointing to four steel structures about tenfeet high, arranged at the corners of a square roughly twenty feetacross, "are miniature radio masts. The area enclosed by them, we willassume, is the city of New York. That metal disc suspended above thearea represents the invader. It contains a miniature heat-generatorsuch as I was experimenting with recently in the Arizona desert."

  He paused, threw a switch. Somewhere in the laboratory a dynamo beganto whir.

  "I am now sending electro-magnetic waves from the four towers," heresumed. "But instead of broadcasting them in every direction. I ambending them in concave cathode of force over the city. You maypicture this cathode as an invisible shield, if you choose, but it ismore than that. It it a reflector. If my theories are right, theradio-energetic ray I am about to project upon it from my miniaturedisc will be flung back to its source as though it had been a ray oflight falling on a mirror. The success of the experiment depends uponwhat the result will be."

  * * * * *

  Kendrick ceased, moved toward a rheostat.

  As he made ready to touch it, a breathless tension settled upon theassemblage. Upon the outcome of what was now to happen rested the fateof America--and the world.

  Calmly, though every fiber of his being was at breaking stress, theyoung scientist opened the rheostat.

  For an instant, the ray seared down--then, as it boomeranged back, thedisc burst into flame, dissolved, disintegrated. A thin dust, likecarbon, slowly settled to the laboratory floor.

  Cutting off the current from the radio towers, Kendrick faced them, alight of triumph in his tired eyes.

  "You see--it works," he said.

  They saw. Beyond a doubt, it worked!

  And what Kendrick saw, as his eyes met Marjorie's, made him forget hisfatigue.

  * * * * *

  The rest was a mad scramble of preparation. Only a few brief hoursremained, and much was to be done.

  The application of the principle that had just been demonstratedinvolved a hook-up from the Consolidated Electric laboratory withevery broadcasting station in the metropolitan area, power beingsupplied by commandeering every generating plant within a radius offifty miles.

  The city, moreover, had to be evacuated of all but the few bravehundreds who volunteered to stand by their posts at radio stations andgenerating plants.

  As for Kendrick, it was the busiest, most hectic morning he had everexperienced. Only the realization of a girl's love and a nation'strust enabled him to overcome the exhaustion of two sleepless nights.

  At length, a little before eleven, all was in readiness. Just twoquestions troubled the young scientist's mind. Had the people of thedisc learned of their preparations to counter the attack? And wouldthe improvised broadcasting apparatus of the area stand the stupendousstrain that would be placed upon it if the ray came down?

  The first of these questions was answered, staggeringly, at a quarterafter eleven.

  "Kendrick--oh, my God!" cried Blake, bursting into the laboratory."Marjorie--they've got her again! Look! Read this!"

  He thrust out a piece of paper. Kendrick took it, read:

  Your daughter will be my queen, after this noon.

  "Where'd you get it?" he gasped.

  "One of the invisible devils thrust it into my hand right out in thestreet, not five minutes ago," Blake explained, trembling withanguish. "Do you realize what this means, Kendrick? She's on the discnow--and in a scant three-quarters of an hour...."

  "Yes, I realize!" his voice came grimly. "And I realize, too, thatthey don't know their fate. They'll stay. There's forty-five minutesyet. We can't abandon our defense against the ray, not even forMarjorie. But I'll go, I'll rescue her--or die with her!"

  And even as Blake mutely reached out his hand to grip that of thedetermined young man who stood before him. Kendrick touched his wristmechanism and went invisible.

  * * * * *

  Once on the street, he pressed the escalator button as well--and bythe strength of the vibrations that followed, he knew he must be veryclose within that mysterious lifting zone.

  Running west a block, he found it growing stronger.

  Fairly racing now, he continued on toward the river, progressunhampered in the deserted streets. Suddenly, with a thrill ofexultation, he felt himself swept up, whirled away toward that greatshimmering hulk against the sun.

  "What hope?" he was thinking. "What possible hope?" And the answercame: Cor!

  Reaching the disc, he switched out the escalator influence andhastened across the city to that monumental structure of jade-greenstone.

  The mighty little dwarf would be up there in his glittering mosaicapartment, or in his pinnacle laboratory, perhaps, ready to pull thelever that would release that stupendous blast of heat.

  Gaining the jewelled door of the monarch's quarters at last, afterescaping detection by a hair's breadth more than once, he p
ressed thebutton outside, just as the guard had done that first time.

  In response, the door opened--and there stood Cor.

  * * * * *

  He stood there an instant, that is, while the expression on hisleathery face went from inquiry to alarm. Then, as Kendrick burst intothe room and shut the door, he went invisible.

  In that same instant, the young scientist's eyes beheld a sight thatcaused his heart to leap. There sat Marjorie, bound in a chair, anexpression half of hope, half of dejection, on her face.

  "It's I--Gordon!" he called. "Take courage!"

  "Oh, I prayed so you'd come--and you came!" she murmured as her facelighted. Then, tensely, she added, "The door--look out!"

  Kendrick wheeled, and just in time. The door was opening.

  "Not so fast!" he called, lunging.

  His hands gripped the dwarf, yanked him back, throttled him before hecould emit a cry, pushed the door shut.

  Cor struggled like a madman, but it was futile. Kendrick's hands cutinto his throat like a vice. After a moment or two, he gasped,relaxed.

  Releasing his grip then, Kendrick felt for his wrist, stripped off hisbracelet--whereupon the dwarf became visible. His face wasputty-white. He was either dead or unconscious.

  Restoring his own visibility then, he advanced to Marjorie, swiftlyfreed her.

  "Take this!" he said, handing her Cor's bracelet.

  She slipped it on.

  "Now let's tie him and get out of here. He may be dead, but we can'ttake any chances."

  * * * * *

  The dwarf wasn't dead, however, for he groaned and opened his eyes asthey lifted him into the chair.

  "You win, Professor--but it avails you nothing!" He smiledmaliciously. "My capture, my death even, will not prevent the ray. Theorders have been given. It will be projected sharp at twelve. You butgo to your doom!"

  "That," said Kendrick, "is a matter of opinion."

  Swiftly they bound him, gagged him.

  "And now," he added, "we wish you good day--and such fate as youdeserve!"

  Then, turning to Marjorie:

  "Your hand again!"

  There was a new tenderness in its soft warmth that thrilled him.

  They touched their buttons, went invisible.

  Silently, then, they stole from the apartment. Swiftly they made theirway down to the concourse, raced across the city to the amber court,descended to the trap-door.

  It must be nearly twelve, Kendrick knew. He couldn't look at hiswatch, for it as well as himself was invisible. Indeed, even as theystood there, poised for the plunge, a faint whistle rose from below.

  Marjorie trembled.

  "Steady!" he spoke. "Some of them always blow a minute or two before.Are you ready?"

  "Yes!"

  "Then press your button--jump!"

  Even as they leapt, the sickening thought came that perhaps theescalator ray was no longer running. But the fear was unwarranted.They were caught up, whirled gently downward.

  Moving along laterally, as they descended, they were able to landwithout difficulty in the middle of a deserted street near theConsolidated Electric laboratory.

  "Thank heaven!" she sighed, as their feet touched solid ground. Theypressed off both buttons, becoming visible once more.

  "Echo!" he agreed. "So let's--"

  * * * * *

  But Kendrick never completed that sentence--for now whistles all overthe metropolitan area, rising from the generating plants, announcedthe ominous hour.

  It was high noon. The ultimatum had expired.

  Lifting tense faces to the disc, they waited. Would that stupendousray be hurled back upon itself? Or would it sear through theirmakeshift defense, plunging them and the whole great metropolis intooblivion?

  Suddenly, cataclysmically, the answer came.

  There burst a withering whirlwind from the disc. It struck that mightyconcave cathode of interlaced waves above the city. There followed aninstant's clash of titanic forces. Then the cathode triumphed, hurledit back.

  Rocked by a concussion as of two worlds in impact, blinded by a glarethat made the sunlight seem feeble in comparison. Marjorie andKendrick clung together, while the disc grew into a satellite ofcalcium fire in the sky.

  Presently, as the conflagration waned, they opened their eyes.Gravely, but with deep thanksgiving, they searched each other's faces.In them they read deep understanding, too, and a new hope.

  "I think we'd better go and find father," she said at length, quietly.

  "I think so too!" he agreed.

  As they headed toward the laboratory, a fine, powdery dust, likevolcanic ash was falling.

  It continued to fall until the city streets were covered to a depth ofan inch or more.

  Thus passed the menace of Vada.

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