THREE AGAINST THE STARS

A sky pirate armed with superior weapons of his own invention....

First contact with an alien race dangerous enough to threaten the safety of two planets....

The arrival of an unseen dark sun whose attendant marauders aimed at the very end of civilization in this Solar System....

These were the three challenges that tested the skill and minds of the brilliant team of scientist-astronauts Arcot, Wade, and Morey. Their initial adventures are a classic of science-fiction which first brought the name of their author, John W. Campbell, into prominence as a master of the inventive imagination.



JOHN W. CAMPBELL first started writing in 1930 when his first short story, When the Atoms Failed, was accepted by a science-fiction magazine. At that time he was twenty years old and still a student at college. As the title of the story indicates, he was even at that time occupied with the significance of atomic energy and nuclear physics.

For the next seven years, Campbell, bolstered by a scientific background that ran from childhood experiments, to study at Duke University and the Massachusetts Institute of Technology, wrote and sold science-fiction, achieving for himself an enviable reputation in the field.

In 1937 he became the editor of Astounding Stories magazine and applied himself at once to the task of bettering the magazine and the field of s-f writing in general. His influence on science-fiction since then cannot be underestimated. Today he still remains as the editor of that magazine's evolved and redesigned successor, Analog.



THE BLACK STAR PASSES

JOHN W. CAMPBELL



ACE BOOKS, INC. 1120 Avenue of the Americas New York, N.Y. 10036



THE BLACK STAR PASSES

Copyright, 1953, by John W. Campbell, Jr.

Copyright, 1930, by Experimenter Publications, Inc.

An Ace Book, by arrangement with the author.

Cover art by Jerome Podwil.



Printed in U.S.A.



Contents

Introduction 7

BOOK ONE

Piracy Preferred 11

BOOK TWO

Solarite 71

BOOK THREE

The Black Star Passes 145



INTRODUCTION

These stories were written nearly a quarter of a century ago, for the old Amazing Stories magazine. The essence of any magazine is not its name, but its philosophy, its purpose. That old Amazing Stories is long since gone; the magazine of the same name today is as different as the times today are different from the world of 1930.

Science-fiction was new, in 1930; atomic energy was a dream we believed in, and space-travel was something we tried to understand better. Today, science-fiction has become a broad field, atomic energy—despite the feelings of many present adults!—is no dream. (Nor is it a nightmare; it is simply a fact, and calling it a nightmare is another form of effort to push it out of reality.)

In 1930, the only audience for science-fiction was among those who were still young enough in spirit to be willing to hope and speculate on a new and wider future—and in 1930 that meant almost nothing but teen-agers. It meant the brightest group of teen-agers, youngsters who were willing to play with ideas and understandings of physics and chemistry and astronomy that most of their contemporaries considered "too hard work."

I grew up with that group; the stories I wrote over the years, and, later, the stories I bought for Astounding Science Fiction changed and grew more mature too. Astounding Science Fiction today has many of the audience that read those early stories; they're not high school and college students any more, of course, but professional engineers, technologists and researchers now. Naturally, for them we need a totally different kind of story. In growing with them, I and my work had to lose much of the enthusiastic scope that went with the earlier science fiction.

When a young man goes to college, he is apt to say, "I want to be a scientist," or "I want to be an engineer," but his concepts are broad and generalized. Most major technical schools, well knowing this, have the first year course for all students the same. Only in the second and subsequent years does specialization start.

By the sophomore year, a student may say, "I want to be a chemical engineer."

At graduation, he may say, "I'm going into chemical engineering construction."

Ten years later he may explain that he's a chemical engineer specializing in the construction of corrosion-resistant structures, such as electroplating baths and pickling tanks for stainless steel.

Year by year, his knowledge has become more specialized, and much deeper. He's better and better able to do the important work the world needs done, but in learning to do it, he's necessarily lost some of the broad and enthusiastic scope he once had.

These are early stories of the early days of science-fiction. Radar hadn't been invented; we missed that idea. But while these stories don't have the finesse of later work—they have a bounding enthusiasm that belongs with a young field, designed for and built by young men. Most of the writers of those early stories were, like myself, college students. (Piracy Preferred was written while I was a sophomore at M.I.T.)

For old-timers in science-fiction—these are typical of the days when the field was starting. They've got a fine flavor of our own younger enthusiasm.

For new readers of science-fiction—these have the stuff that laid the groundwork of today's work, they're the stories that were meant for young imaginations, for people who wanted to think about the world they had to build in the years to come.

Along about sixteen to nineteen, a young man has to decide what is, for him, the Job That Needs Doing—and get ready to get in and pitch. If he selects well, selects with understanding and foresight, he'll pick a job that does need doing, one that will return rewards in satisfaction as well as money. No other man can pick that for him; he must choose the Job that he feels fitting.

Crystal balls can be bought fairly reasonably—but they don't work well. History books can be bought even more cheaply, and they're moderately reliable. (Though necessarily filtered through the cultural attitudes of the man who wrote them.) But they don't work well as predicting machines, because the world is changing too rapidly.

The world today, for instance, needs engineers desperately. There a lot of jobs that the Nation would like to get done that can't even be started; not enough engineers available.

Fifty years ago the engineering student was a sort of Second Class Citizen of the college campus. Today the Liberal Arts are fighting for a come-back, the pendulum having swung considerably too far in the other direction.

So science-fiction has a very real function to the teen-agers; it presents varying ideas of what the world in which he will live his adult life will be interested in.

This is 1953. My son will graduate in 1955. The period of his peak earning power should be when he's about forty to sixty—about 1970, say, to 1990. With the progress being made in understanding of health and physical vigor, it's apt to run beyond 2000 A.D., however.

Anyone want to bet that people will be living in the same general circumstances then? That the same general social and cultural and material standards will apply?

I have a hunch that the history books are a poor way of planning a life today—and that science-fiction comes a lot closer.

There's another thing about science-fiction yarns that is quite conspicuous; it's so difficult to pick out the villains. It might have made quite a change in history if the ballads and tales of the old days had been a little less sure of who the villains were. Read the standard boy's literature of forty years ago; tales of Crusaders who were always right, and Saracens who were always wrong. (The same Saracens who taught the Christians to respect the philosophy of the Greeks, and introduced them to the basic ideas of straight, self-disciplined thinking!)

Life's much simpler in a thatched cottage than in a dome on the airless Moon, easier to understand when the Villains are all pure black-hearted villains, and the Heroes are all pure White Souled Heroes. Just look how simple history is compared with science-fiction! It's simple—but is it good?

These early science-fiction tales explored the Universe; they were probings, speculations, as to where we could go. What we could do.

They had a sweep and reach and exuberance that belonged.

They were fun, too....

John W. Campbell, Jr. Mountainside, N.J. April, 1953



BOOK ONE

PIRACY PREFERRED



PROLOGUE

High in the deep blue of the afternoon sky rode a tiny speck of glistening metal, scarcely visible in the glare of the sun. The workers on the machines below glanced up for a moment, then back to their work, though little enough it was on these automatic cultivators. Even this minor diversion was of interest in the dull monotony of green. These endless fields of castor bean plants had to be cultivated, but with the great machines that did the work it required but a few dozen men to cultivate an entire county.

The passengers in the huge plane high above them gave little thought to what passed below, engrossed with their papers or books, or engaged in casual conversation. This monotonous trip was boring to most of them. It seemed a waste of time to spend six good hours in a short 3,500 mile trip. There was nothing to do, nothing to see, except a slowly passing landscape ten miles below. No details could be distinguished, and the steady low throb of the engines, the whirring of the giant propellers, the muffled roar of the air, as it rushed by, combined to form a soothing lullaby of power. It was all right for pleasure seekers and vacationists, but business men were in a hurry.

The pilot of the machine glanced briefly at the instruments, wondered vaguely why he had to be there at all, then turned, and leaving the pilot room in charge of his assistant, went down to talk with the chief engineer.

His vacation began the first of July, and as this was the last of June, he wondered what would have happened if he had done as he had been half inclined to do—quit the trip and let the assistant take her through. It would have been simple—just a few levers to manipulate, a few controls to set, and the instruments would have taken her up to ten or eleven miles, swung her into the great westward air current, and leveled her off at five hundred and sixty or so an hour toward 'Frisco'. They would hold her on the radio beam better than he ever could. Even the landing would have been easy. The assistant had never landed a big plane, but he knew the routine, and the instruments would have done the work. Even if he hadn't been there, ten minutes after they had reached destination, it would land automatically—if an emergency pilot didn't come up by that time in answer to an automatic signal.

He yawned and sauntered down the hall. He yawned again, wondering what made him so sleepy.

He slumped limply to the floor and lay there breathing ever more and more slowly.

* * * * *

The officials of the San Francisco terminus of The Transcontinental Airways company were worried. The great Transcontinental express had come to the field, following the radio beam, and now it was circling the field with its instruments set on the automatic signal for an emergency pilot. They were worried and with good reason, for this flight carried over 900,000 dollars worth of negotiable securities. But what could attack one of those giant ships? It would take a small army to overcome the crew of seventy and the three thousand passengers!

The great ship was landing gently now, brought in by the emergency pilot. The small field car sped over to the plane rapidly. Already the elevator was in place beside it, and as the officials in the car drew up under the giant wing, they could see the tiny figure of the emergency pilot beckoning to them. Swiftly the portable elevator carried them up to the fourth level of the ship.

What a sight met their eyes as they entered the main salon! At first glance it appeared that all the passengers lay sleeping in their chairs. On closer examination it became evident that they were not breathing! The ear could detect no heartbeat. The members of the crew lay at their posts, as inert as the passengers! The assistant pilot sprawled on the floor beside the instrument panel—apparently he had been watching the record of the flight. There was no one conscious—or apparently living—on board!

"Dead! Over three thousand people!" The field manager's voice was hoarse, incredulous. "It's impossible—how could they have done it? Gas, maybe, drawn in through the ventilator pumps and circulated through the ship. But I can't conceive of any man being willing to kill three thousand people for a mere million! Did you call a doctor by radio, Pilot?"

"Yes, sir. He is on his way. There's his car now."

"Of course they will have opened the safe—but let's check anyway. I can only think some madman has done this—no sane man would be willing to take so many lives for so little." Wearily the men descended the stairs to the mail room in the hold.

The door was closed, but the lock of the door was gone, the magnesium-beryllium alloy burned away. They opened the door and entered. The room seemed in perfect order. The guard lay motionless in the steel guard chamber at one side; the thick, bullet-proof glass made his outlines a little blurred, and the color of his face was green—but they knew there too must be that same pallor they had seen on the other faces. The delicate instruments had brought in the great ship perfectly, but it was freighted with a cargo of dead!

They entered the room and proceeded to the safe, but it was opened as they had expected. The six-inch tungsto-iridium wall had been melted through. Even this unbelievable fact no longer surprised them. They only glanced at the metal, still too hot to touch, and looked about the room. The bonds had been taken. But now they noticed that over the mail-clerk's desk there had been fastened a small envelope. On it was printed:

To the Officials of the San Francisco Airport

Inside was a short message, printed in the same sharp, black letters:

Gentlemen:

This plane should land safely. If it doesn't, it is your fault, not mine, for the instruments that it carries should permit it. The passengers are NOT dead! They have been put in a temporary state of suspended animation. Any doctor can readily revive them by the injection of seven c.c. of decinormal potassium iodide solution for every 100 pounds of weight. Do NOT use higher concentrations. Lower concentrations will act more slowly.

You will find that any tendency toward leprosy or cancer will have been destroyed. It will kill any existing cancer, and cure it in about one week. I have not experimented with leprosy beyond knowing that it is cured very quickly.

This is an outside job. Don't annoy the passengers with questions.

The gas used cannot be stopped by any material I know of. You can try it with any mask—but don't use the C-32L. It will react with the gas to kill. I would advise that you try it on an animal to convince yourselves.

I have left stock in my new company to replace the bonds I have taken.

Piracy Incorporated is incorporated under my own laws.

The Pirate

On the desk beneath the note was a small package which contained a number of stock certificates. They totalled $900,000 face value of "Piracy Preferred", the preferred stock of a corporation, "Piracy, Inc."

"Piracy! Pirates in the air!" The field manager forced an unnatural laugh. "In 2126 we have pirates attacking our air lines. Piracy Preferred! I think I'd prefer the bonds myself. But thank God he did not kill all those people. Doctor, you look worried! Cheer up. If what this pirate says is true, we can resuscitate them, and they'll be better off for the experience!"

The doctor shook his head. "I've been examining your passengers. I'm afraid that you'll never be able to bring these people back to life again, sir. I can't detect any heart action even with the amplifier. Ordinary heart action sounds like a cataract through this instrument. I can see nothing wrong with the blood; it has not coagulated as I expected, nor is there any pronounced hydrolysis as yet. But I'm afraid I'll have to write out the death warrants for all these men and women. One of the people on that ship was coming to see me. That's how I happened to be on the field. For her, at least, it may be better so. The poor woman was suffering from an incurable cancer."

"In this case, Doctor, I hope and believe you are wrong. Read this note!"

* * * * *

It was two hours before the work of reviving the passengers could be started. Despite all the laws of physics, their body temperature had remained constant after it had reached seventy-four, showing that some form of very slow metabolism was going on. One by one they were put into large electric blankets, and each was given the correct dose of the salt. The men waited anxiously for results—and within ten minutes of the injection the first had regained consciousness!

The work went forward steadily and successfully. Every one of the passengers and crew was revived. And the Pirate had spoken the truth. The woman who had been suffering from cancer was free from pain for the first time in many months. Later, careful examination proved she was cured!

The papers were issuing extras within five minutes of the time the great plane had landed, and the radio news service was broadcasting the first "break" in a particularly dead month. During all of June the news had been dead, and now July had begun with a bang!

With time to think and investigate, the airport officials went over the ship with the Air Guard, using a fine-tooth comb. It was soon evident that the job had been done from the outside, as the Pirate had said. The emergency pilot testified that when he entered the ship, he found a small piece of wire securing the air lock from the outside. This had certainly been put on while the ship was in flight, and that meant that whoever had done this, had landed on the great ship with a small plane, had somehow anchored it, then had entered the plane through the air lock at the ten mile height. He had probably flown across the path of the plane, leaving a trail of gas in its way to be drawn in through the ventilator pumps. It had been washed out by the incoming good air later, for the emergency pilot had not been affected.

Now the investigation led them to the mail-room. Despite the refractory nature of the metal, the door had been opened by melting or burning out the lock. And an opening had been burned into the safe itself! Opened by melting it through!

A bond shipment was due the next day, and the airline officials planned to be on the watch for it. It would get through safely, they were sure, for men were put on board in steel chambers hermetically welded behind them, with oxygen tanks and automatic apparatus sealed within to supply them with clean air. The front of the tanks were equipped with bullet-proof glass windows, and by means of electrically operated controls the men inside could fire machine guns. Thus they were protected from the Pirate's gas and able to use their weapons.

The ship was accompanied by a patrol of Air Guardsmen. Yet, despite, this, cancer cases were aboard with the hope of being gassed.

When the plane reached the neighborhood of San Francisco, there had been no sign of an attack. The Pirate might well retire permanently on a million, if he were alone, as the singular signature indicated; but it seemed much more probable that he would attempt another attack in any case. Well, that just meant watching all the planes from now on, a tremendous job for the Air Guard to handle.

The leader of the patrol turned in an easy bank to descend the ten miles to Earth, and his planes followed him. Then suddenly through the communicator came an unmistakable sound. The plane automatically signaling for an emergency pilot! That could only mean that the plane had been gassed under the very eyes of his men!

The bonds were gone and the passengers gassed, and incredibly, the men in the steel tanks were as thoroughly gassed as the rest.

The note was brief, and as much to the point as was the absence of the bonds.

To the Officials of the Airport:

Restore as usual. The men in the tanks are asleep also—I said the gas would penetrate any material. It does. A mask obviously won't do any good. Don't try that C-32L mask. I warn you it will be fatal. My gas reacts to produce a virulent poison when in contact with the chemicals in the C-32L.

The Pirate



I.

On the thirty-ninth floor of a large New York apartment two young men were lounging about after a strenuous game of tennis. The blue tendrils of smoke from their pipes rose slowly, to be drawn away by the efficient ventilating system. The taller of the two seemed to be doing most of the talking. In the positions they had assumed it would have been rather difficult to be sure of which was the taller, but Robert Morey was a good four inches taller than Richard Arcot. Arcot had to suffer under the stigma of "runt" with Morey around—he was only six feet tall.

The chosen occupation of each was physical research, and in that field Arcot could well have called Morey "runt", for Arcot had only one competitor—his father. In this case it had been "like father, like son". For many years Robert Arcot had been known as the greatest American physicist, and probably the world's greatest. More recently he had been known as the father of the world's greatest physicist. Arcot junior was probably one of the most brilliant men the world had ever seen, and he was aided in all his work by two men who could help him in a way that amplified his powers a thousand fold. His father and his best friend, Morey, were the complimentary and balancing minds to his great intelligence. His father had learned through years of work the easiest and best ways of performing the many difficult feats of laboratory experimentation. Morey could develop the mathematical theory of a hypothesis far more readily than Arcot could. Morey's mind was more methodical and exact than Arcot's, but Arcot could grasp the broad details of a problem and get the general method of solution developed with a speed that made it utterly impossible for his friend even to follow the steps he suggested.

Since Arcot junior's invention of the multiple calculus, many new ramifications of old theories had been attained, and many developments had become possible.

But the factor that made Arcot so amazingly successful in his line of work was his ability to see practical uses for things, an ability that is unfortunately lacking in so many great physicists. Had he collected the royalties his inventions merited, he would have been a billionaire twice or thrice over. Instead he had made contracts on the basis that the laboratories he owned be kept in condition, and that he be paid a salary that should be whatever he happened to need. Since he had sold all his inventions to Transcontinental Airways, he had been able to devote all his time to science, leaving them to manage his finances. Perhaps it was the fact that he did sell these inventions to Transcontinental that made these lines so successful; but at any rate, President Arthur Morey was duly grateful, and when his son was able to enter the laboratories he was as delighted as Arcot.

The two had become boon companions. They worked, played, lived, and thought together.

Just now they were talking about the Pirate. This was the seventh day of his discovery, and he had been growing steadily more menacing. It was the great Transcontinental Airways that had suffered most repeatedly. Sometimes it was the San Francisco Flyer that went on without a pilot, sometimes the New York-St. Louis expresses that would come over the field broadcasting the emergency signal. But always the people were revived with little difficulty, and each time more of the stock of "Piracy, Inc." was accumulated. The Air Guard seemed helpless. Time and time again the Pirate slipped in undetected. Each time he convinced them that it was an outside job, for the door was always sealed from the outside.

"Dick, how do you suppose he gets away with the things he does right under the eyes of those Air Guardsmen? He must have some system; he does it every time."

"I have a vague idea," Arcot answered. "I was going to ask you today, if your father would let us take passage on the next liner carrying any money. I understand the insurance rates have been boosted so high that they don't dare to send any cash by air any more. They've resorted to the slow land routes. Is there any money shipment in sight?"

Morey shook his head. "No, but I have something that's just as good, if not better, for our purpose. The other day several men came into Dad's office, to charter a plane to San Francisco, and Dad naturally wondered why they had been referred to the president of the company. It seems the difficulty was that they wanted to hire the ship so they could be robbed! A large group of medical men and cancer victims were going for the 'treatment'. Each one of the twenty-five hundred going was to bring along one hundred dollars. That meant a total of a quarter of a million dollars, which is to be left on the table. They hoped the Pirate would gas them and thus cure them! Dad couldn't officially do this, but told them that if there were too many people for the San Francisco express, two sections would be necessary. I believe they are going on that second section. Only one hundred dollars! A low price for cancer cure!

"Another thing: Dad asked me to tell you that he'd appreciate your help in stopping this ultra-modern pirate. If you go down to see him in the morning, you'll doubtless be able to make the necessary arrangements."

"I'll do so gladly. I wonder, though, if you know more about this than I do. Did they try that C-32L mask on an animal?"

"The Pirate was telling the truth. They tried it on a dog and he went to sleep forever. But do you have any idea how that gas does all it does?"

Now Arcot shook his head. "I don't know what the gas is, but have a lead on how it works. You may know that carbon monoxide will seep through a solid plate of red-hot steel. That has been known for some three hundred years now, and I have to hand it to this Pirate for making use of it. Even in the war of 2075 they didn't find any practical application for the principle. He has just found some gas that induces sleep in very low concentrations, and at the same time is able to penetrate to an even greater extent than carbon monoxide."

"I was wondering how he stores that stuff," Morey commented. "But I suppose he makes it as fast as he uses it, by allowing two or more constituents to react. It might well be simple enough to store them separately, and the air-stream blowing past him would carry the gas behind him, permitting him to lay a stream of it in front of the big plane. Is that about it?"

"That was about what I had figured. One of the things I want to do when I go with that Invalid Special tomorrow is to get some samples for analysis."

"That's a pretty big order, isn't it, Dick? How are you going to handle it, or even get it into your apparatus?"

"Easily enough as far as getting the sample goes. I have already had some sample bottles made. I have one of them in the lab—excuse me a moment." Arcot left the room, to return a few minutes later with a large aluminum bottle, tightly closed. "This bottle has been pumped out to a very good vacuum. I then swept it out with helium gas. Then it was pumped out again. I hope to take this into some gas-filled region, where the gas will be able to leak in, but the air won't. When it comes to going out again, the gas will have to fight air pressure, and will probably stay in."

"Hope it works. It would help if we knew what we were bucking."

* * * * *

The next morning Arcot had a long conference with President Morey. At the end of it, he left the office, ascended to the roof, and climbed into his small helicopter. He rose to the local traffic level, and waiting his chance, broke into the stream of planes bound for the great airfields over in the Jersey district. A few minutes later he landed on the roof of the Transcontinental Airways shops, entered them, and went to the office of the Designing Engineer, John Fuller, an old schoolmate. They had been able to help each other before, for Fuller had not paid as much attention to theoretical physics as he might have, and though he was probably one of the outstanding aeronautical designers, he often consulted Arcot on the few theoretical details that he needed. Probably it was Arcot who derived the greatest benefit from this association, for the ability of the designer had many times brought his theoretical successes to practical commercial production. Now, however, he was consulting Fuller, because the plane he was to take that afternoon for San Francisco was to be slightly changed for him.

He stayed in Fuller's office for the better part of an hour, then returned to the roof and thence to his own roof, where Morey junior was waiting for him.

"Hello, Dick! I heard from Dad that you were going this afternoon, and came over here. I got your note and I have the things fixed up here. The plane leaves at one, and it's ten-thirty now. Let's eat lunch and then start."

It was half-past eleven when they reached the flying field. They went directly to the private office which had been assigned to them aboard the huge plane. It was right next to the mail-room, and through the wall between the two a small hole had been cut. Directly beneath this hole was a table, on which the two men now set up a small moving picture camera they had brought with them.

"How many of the gas sample bottles did you bring, Bob?" asked Arcot.

"Jackson had only four ready, so I brought those. I think that will be enough. Have we got that camera properly placed?"

"Everything's O.K., I believe. Nothing to do now but wait."

Time passed—then they heard a faint whir; the ventilator machinery had started. This drew air in from outside, and pumped it up to the necessary pressure for breathing in the ship, no matter what the external pressure might be. There was a larger pump attached similarly to each of the engines to supply it with the necessary oxygen. Any loss in power by pumping the air in was made up by the lower back pressure on the exhaust. Now the engines were starting—they could feel the momentary vibration—vibration that would cease as they got under way. They could visualize the airtight door being closed; the portable elevator backing off, returning to the field house.

Arcot glanced at his watch. "One o'clock. The starting signal is due."

Morey sank back into a comfortable chair. "Well, now we have a nice long wait till we get to San Francisco and back, Dick, but you'll have something to talk about then!"

"I hope so, Bob, and I hope we can return on the midnight plane from San Francisco, which will get us in at nine o'clock tomorrow morning, New York time. I wish you'd go right to your father's office and ask him over to our place for supper, and see if Fuller can come too. I think we'll be able to use that molecular controller on this job; it's almost finished, and with it we'll need a good designing engineer. Then our little movie show will no doubt be of interest!"

There was a low rumble that quickly mounted to a staccato roar as the great propellers began whirling and the engines took up the load. The ground began to flash behind them; then suddenly, as flying speed was reached, there was a slight start, the roaring bark of the engine took on a deeper tone, the rocking stopped and the ground dropped away. Like some mighty wild bird, the plane was in the air, a graceful, sentient thing, wheeling in a great circle as it headed for San Francisco. Now the plane climbed steadily in a long bank; up, up, up she went, and gradually the terrific roar of the engine died to a low throbbing hum as the low pressure of the air silenced the noise.

Below them the giant city contracted as the great ship rode higher. The tiny private helicops were darting about below them like streams of nigh invisible individuals, creeping black lines among the buildings of the city. The towering buildings shone in the noon sun in riotous hues as the colored tile facing reflected the brilliant sunlight with glowing warmth of color.

It was a city of indescribable beauty now. It was one of the things that made this trip worthwhile.

Now the shining city dropped behind them, and only the soft green of the Jersey hills, and the deep purple-black of the sky above were visible. The sun blazed high in the nigh-black heavens, and in the rarefied air, there was so little diffusion that the corona was readily visible with the aid of a smoked glass. Around the sun, long banners in space, the Zodiacal light gleamed dimly. Here and there some of the brighter stars winked in the dark sky.

Below them the landscape swung slowly by. Even to these men who had made the trip dozens of times, the sight was fascinating, inspiring. It was a spectacle which had never been visible before the development of these super-planes. Whole flying observatories had been made that had taken photographs at heights of fifteen miles, where the air was so rarefied that the plane had to travel close to eight hundred miles an hour to remain aloft.

Already ahead of them Arcot and Morey could see the great splotch of color that was Chicago, the mightiest city of Earth. Situated as it was in the heart of the North American continent, with great water and ground landing facilities and broad plains about it, it made a perfect airport. The sea no longer meant much, for it was now only a source of power, recreation and food. Ships were no longer needed. Planes were faster and more economical; hence seacoast cities had declined in importance. With its already great start toward ascendancy, Chicago had rapidly forged ahead, as the air lines developed with the great super-planes. The European planes docked here, and it was the starting point of the South American lines. But now, as they swung high above it, the glistening walls of soft-colored tiles made it a great mass of changing, flashing color beneath them. Now they could see a great air liner, twice the size of their plane, taking off for Japan, its six giant propellers visible only as flashing blurs as it climbed up toward them. Then it was out of sight.

It was over the green plains of Nebraska that the Pirate usually worked, so there the men became more and more alert, waiting for the first sign of abnormal drowsiness. They sat quietly, not talking, listening intently for some new note, but knowing all the while that any sound the Pirate might make would be concealed by the whirring roar of the air sweeping past the giant airfoils of the plane.

Suddenly Arcot realized he was unbearably sleepy. He glanced drowsily toward Morey who was already lying down. He found it a tremendous effort of the will to make himself reach up and close the switch that started the little camera whirring almost noiselessly. It seemed he never pulled his arm back—he just—lay there—and—

A white uniformed man was bending over him as he opened his eyes. To one side of him he saw Morey smiling down at him.

"You're a fine guard, Arcot. I thought you were going to stay awake and watch them!"

"Oh, no, I left a much more efficient watchman! It didn't go to sleep—I'm willing to bet!"

"No, it may not have gone to sleep, but the doctor here tells me it has gone somewhere else. It wasn't found in our room when we woke up. I think the Pirate found it and confiscated it. All our luggage, including the gas sample bottles, is gone."

"That's all right. I arranged for that. The ship was brought down by an emergency pilot and he had instructions from father. He took care of the luggage so that no member of the pirate's gang could steal it. There might have been some of them in the ground crew. They'll be turned over to us as soon as we see the emergency man. I don't have to lie here any longer, do I, doctor?"

"No, Dr. Arcot, you're all right now. I would suggest that for the next hour or so you take it easy to let your heart get used to beating again. It stopped for some two hours, you know. You'll be all right, however."



II

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

Arcot commented: "I have cut out a lot of useless film, and confined the picture 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, and then, to their intense surprise, it remained open for a few seconds, then closed. It went through all the motions of opening to admit someone, yet no one entered!

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

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

Now the scene seemed to swing a bit as the plane hit an unusually bad air bump, and through the window they caught a glimpse of one of the circling Air Guardsmen. Then suddenly there appeared in the air within the room a point of flame. It hung in the air above the safe for an instant, described a strangely complicated set of curves; then, as it hung for an instant in mid-air, it became a great flare. In an instant this condensed to a point of intensely brilliant crimson fire. This described a complex series of curves and touched the top of the safe. In an inconceivably short time, the eight-inch thickness of tungsto-iridium alloy flared incandescently and began to flow sluggishly. A large circle of the red flame sprang out to surround the point of brilliance, and this 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 the safe, again retracting itself in that uncanny manner, no force seeming either to supply it with fuel or to support it thus, though it burned steadily, and worked rapidly and efficiently. Now, in mid-air, it hung for a second.

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

The pictures seemed to show the flame slowly descending till it again touched the metal. The tungsto-iridium glowed briefly; then, as suddenly as the extinguishing of a light, the safe was gone! It had disappeared into thin air! Only the incandescence of the metal and the flame itself were visible.

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

The projector had been stopped exactly on the first frame, showing the invisibility 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 mail clerk asleep at his desk, everything as before, except that where the safe had been, there was a shadowy, half visible safe, the metal glowing brightly. Beside it there was visible a shadowy man, holding the safe with a shadowy bar of some sort. And through both of them the frame of the window was perfectly visible, and, ironically, an Air Guardsman plane.

"It seems that for an instant his invisibility failed here. Probably it was 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 is even theoretically possible. Have you any ideas?"

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

* * * * *

The next evening, however, it seemed that it was Arcot himself who could not be there. He asked Morey, junior, to tell them he would be there later, when he had finished in the lab.

Dinner was over now, and the men were waiting rather impatiently for Arcot to come. They heard some noise in the corridor, and looked up, but no one entered.

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

"As to the gas, Dick found out but little more than we had already known. It is a typical organic compound, one of the metal radical type, and contains one atom of thorium. This is a bit radioactive, as you know, and Dick thinks that this may account in part for its ability to suspend animation. However, since it was impossible to determine the molecular weight, he could not say what the gas was, save that the empirical formula was C{62}TH H{39}O{27}N{5}. It broke down at a temperature of only 89 deg. centigrade. The gases left consisted largely of methane, nitrogen, and methyl ether. Dick is still in the dark as to what 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 rather puzzled. What they then saw, or better, failed to see, puzzled them still more. Morey had disappeared!

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

There was a short laugh from the air—certainly there could be nothing else there—then a low but distinct click, and both Morey and Arcot were miraculously present, coming instantaneously from nowhere, if one's senses could be relied on. On Arcot's back there was strapped a large and rather hastily wired mechanism—one long wire extending from it out into the laboratory. He was carrying a second piece of apparatus, similarly wired. Morey was touching a short metal bar that Arcot held extended in his hand, using a table knife as a connector, lest they get radio frequency burns on making contact.

"I've been busy getting the last connection of this portable apparatus rigged 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 important to 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 rather dangerously high E.M.F. I had to connect with the lab power supply to do this, and I had no time to rig up a little mechanism like the one the pirate must have.

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

"The whole thing looks to me to be the work of a slightly unbalanced mind. He is not violently insane; probably just has this one particular obsession. His scientific bump certainly shows no sign of weakness. He might even be some new type of kleptomaniac. He steals things, and he has 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. He is not violent, for hasn't he carefully warned the men not to use the C-32L mask? You'll remember his careful instructions as to how to revive the people!

"He has developed this machine for invisibility, and naturally he can fly in and out of the air guard, without their knowing he's there, provided their microphonic detectors don't locate him. I believe he uses some form of glider. He can't use an internal combustion engine, for the explosions in the cylinders would be as visible as though the cylinders were made of clear quartz. He cannot have an electric motor, for the storage cells would weigh too much. Furthermore, if he were using any sort of prop, or a jet engine, the noise would give him away. If he used a glider, the noise of the big plane so near would be more than enough to kill the slight sounds. The glider could hang above the ship, then dive down upon it as it passed beneath. He has a very simple system of anchoring the thing, as I discovered to my sorrow. It's a powerful electro-magnet which he turns on when he lands. The landing deck of the big plane was right above our office aboard, and I found my watch was doing all sorts of antics today. It lost an hour this morning, and this afternoon it gained two. I found it was very highly magnetized—I could pick up needles with the balance wheel. I demagnetized it; now it runs all right.

"But to get back, he anchors his ship, then, leaving it invisible, he goes to the air lock, and enters. He wears a high altitude suit, and on his 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 a problem, but I think I would use a cylinder of liquid air, and have a small air turbine to run a high voltage generator. He probably uses the same system on a larger scale to run his big machine on the ship. He can't use an engine for that either.

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

"As to the machine here—it is, as I said, a machine which impresses very high frequencies on the body it is connected with. This puts the molecules in vibration at a frequency approaching that of light, and when the light impinges upon it, it can pass through readily. You know that metals transmit light for short distances, but in order that the light pass, the molecules of metal must be set in harmonic vibration at a rate approaching the frequency of light. If we can impress such a vibration 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 pass through 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 a machine that is perfectly transparent when there is nothing but perfectly transparent air around it? It is a curious property of this vibrational system of invisibility that the index of refraction is made very low. It is not the same as that of air, but the difference is so slight that it is practically within the limits of observation error; so small is the difference that there is no 'rainbow' effect. The difference of temperature of the air would give equal effect.

"Now, since this vibration is induced by radio impulse, is it not possible to impress another, opposing radio impulse, that will overcome this tendency and bring the invisible object into the field of the visible once more? It is; and this machine on the table is designed to do exactly that. It is practically a beam radio set, projecting a beam of a wavelength that alone would tend to produce invisibility. But in this case it will make me visible. I'm going to stand right here, and Bob can operate that set."

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

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

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

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

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

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

"I can promise you a tough problem as well as an interesting one." Arcot smiled. "If the thing works, as I expect it to, you'll have a job that will 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 that pirate could give us some hints on design. How does he get his glider ten miles up? They've done some high-altitude gliding already. The distance record took someone across the Atlantic in 2009, didn't it? But it 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 a semi-glider. He probably goes up ten miles or more with the aid of a small engine, one so small it probably takes him half a day to get there. And it would be easy for a plane to pass through the lower traffic lanes, then, being invisible, mount high and wait for the air liner. He can't use a very large engine, for it would drag him down, but one of the new hundred horsepower jobs would weigh only about fifty pounds. I think we can draw a pretty good picture of his plane from scientific logic. It probably has a tremendous wingspread and a very high angle of incidence to make it possible to glide at that height, and the engine and prop will be almost laughably small."

* * * * *

The next evening the men got together for dinner, and there was considerable speculation as to the nature of the discovery that Arcot was going to announce, for even his father had no knowledge of what it was. The two men worked in separate laboratories, except when either had a particularly difficult problem that might be solved by the other. All knew 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 in hand.

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

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

"Well, the more I investigate the thing, the more I wonder which is the greatest. 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't dependable for night work, is the difficulty of getting an area to absorb the energy. If I could get enough area, I could use a very low efficiency 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 area to use, if you can only harness the energy it absorbs. I have really developed a very efficient solar engine. The engine itself requires no absorbing area, as I want to use it; it takes advantage of the fact that the Earth is absorbing quintillions of horsepower. I have merely tapped the power that the Earth has already absorbed for me. Come here."

He led the way down the corridor to his laboratory, and switched on the lights. On the main laboratory bench was set up a complicated apparatus of many tubes and heavy bus bar connectors. From the final tube two thin wires ran to a long tubular coil. To the left of this coil was a large relay 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 a solar engine, and nine o'clock at night seems a peculiar hour to demonstrate such a thing, but I'll guarantee results—probably more than you expect."

Dr. Arcot stepped up to the controls and closed the switch. The lights dimmed a bit, but immediately brightened again, and from the other end of the room came a low, steady hum as the big transformer took up the load.

"Well, from the sound of that ten K.W. transformer there, if this engine is 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 control this except by standing directly in front of it, but I suppose you know what you're doing."

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

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

The astonished physicist came forward and looked at the device a moment in silence, while each of the other men watched him. Finally he turned to 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 more lucrative than any other method ever invented! If the principle of this machine is what I think it is, you have certainly solved the secret of a sufficiently absorbing area for a solar engine."

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

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

"Rather important," broke in the inventor's father, with a rare display of excitement. "It will be considerably more than that. It's the biggest thing since the electric dynamo! It puts airplanes in the junk heap! It means a new era in power generation. Why, we'll never have to worry about power! It will make interplanetary travel not only possible, but commercially economical."

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

"But why do it at all? The sun is doing it already, and on a scale so gargantuan that we could never hope nor desire to approach it. Three million tons of matter go into that colossal furnace every second of time, 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 ergs to draw on, man will have nothing to worry about for a good many years to come! That represents a flood of power vaster than man could comprehend. Why try to release any more energy? We have more than we can use; we may as well tap that vast ocean of power.

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

Arcot paused, frowning, then resumed half apologetically, "Excuse the lecture—but I don't know how else to get the thought across. You are familiar with the conditions in a liter of helium gas in a container—a tremendous number of molecules, each dashing along at several miles a second, and an equal number dashing in the opposite direction at an equal speed. They are so thickly packed in there, that none of them can go very far before it runs into another molecule and bounces off in a new direction. How good is the chance that all the molecules should happen to move in the same direction at the same time? One of the old physicists of Einstein's time, a man named Eddington, expressed it very well:

'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 our problem appear impossible.

"But similarly it would be improbable—impossible according to the law of chance—to throw a string of aces indefinitely. It is impossible—unless some other force influences the happening. If the dice have bits of iridium stuck under the six spots, they will throw aces. Chance makes it impossible to have all the molecules of gas move in the same direction at the same time—unless we stack the chances. If we 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 to move in the same direction at the same time? Their heat motion is normally carrying them about at a rate of several miles a second, and if now we have them all go in one way, the entire bar must move in that direction, and it will start off at a velocity as great as the velocity of the individual molecules. But now, if we attach the bar to a heavy car, it will try to start off, but will be forced to drag the car with it, and so will not be able to have its molecules moving at the same rate. They will be slowed down in starting the mass of the car. But slowly moving molecules have a definite physical significance. Molecules move because of temperature, and lack of motion means lack of heat. These molecules that have been slowed down are then cold; they will absorb heat from the air about them, and since the molecule of hydrogen gas at room temperature is moving at about seven miles a second, when the molecules of the confined gas in our car, or the molecules of the metal bar are slowed down to but a few hundred miles an hour, their temperature drops to some hundreds of degrees below zero, and they absorb energy very rapidly, for the greater the difference in temperature, the greater the rate of heat absorption.

"I believe we will be able to accelerate the car rapidly to a speed of several miles a second at very high altitudes, and as we will be able to use a perfectly enclosed streamlined car, we should get tremendous speeds. We'll need no wings, of course, for with a small unit pointed vertically, we'll be able to support the car in the air. It will make possible a machine that will be able to fly in reverse and so come to a quick 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 the circumference of the generator, and get a tremendously powerful engine.

"For our present need, it means a tremendously powerful engine—and one that we can make invisible.

"I believe you can guess the source of that breeze we had there? It would 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 the economics of the thing, if not its science, to know that the apparatus before us is absolutely invaluable. I couldn't afford to buy the rights on it, but I want to use it if you'll let me. It means a new era in transcontinental air travel!"

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

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

"It's done," Morey snapped.



III

Early the next morning Fuller moved his equipment over to the laboratory and set up his table for work. There Arcot and Morey joined him, and the designing of the new machine was started.

"First, let's get some idea of the most advisable shape," Fuller began methodically. "We'll want it streamlined, of course; roughly speaking, a cylinder modified to fit the special uses to which it will be put. But you probably have a general plan in mind, Arcot. Suppose you sketch it for us."

The big physicist frowned thoughtfully. "Well, we don't know much about this yet, so we'll have to work it out. You'll have plenty of fun figuring out strains in this machine, so let's be safe and use a factor of safety of five. Let's see what we'll need.

"In the first place, our machine must be proof against the Pirate's gas, for we won't be riding a beam with instruments to guide us safely, if we pass out. I've thought that over, and I think that the best system is just what we used in the sample bottles—a vacuum. His gas is stopped by nothing, so to speak, but there is no substance that will stop it! It will no doubt penetrate the outer shell, but on reaching the vacuum, it will tend to stay there, between the inner and outer walls. Here it will collect, since it will be fighting air pressure in going either in or out. The pressure inside will force it back, and the pressure outside will force it in. If we did not pump it out, it would soon build up pressure enough to penetrate the interior wall. Now, since the stuff can leak through any material, what kind of a pump shall we use? It won't be pushed by a piston, for it will leak through either the cylinder walls or the piston. A centrifugal pump would be equally ineffective. A mercury vapor pump will take it out, of course, and keep a high vacuum, but we'd never make any progress.

"Our new machine gives us the answer. With it we can just have a number of openings in the wall of the outer shell, and set in them one of these molecular motion directors, and direct the molecules into the outside air. They can't come in through it, and they will go out!"

"But," Morey objected, "the vacuum that keeps out the gas will also keep out heat, as well! Since our generator is to run on heat energy, it will be rather chilly inside if we don't remedy that. Of course, our power units could be placed outside, where the blast of air will warm them, but we really won't have a very good streamline effect if we hang a big electric generator outside."

"I've thought of that too," Arcot answered. "The solution is obvious—if we can't bring the generator to the air, we must bring the air to it." He began sketching rapidly on the pad before him, "We'll have all the power equipment in this room here in the back, and the control room up in front, here. The relays for controlling will be back here, so we can control electrically the operation of the power equipment from our warm, gas-tight room. If it gets too warm in there, we can cool it by using a little of the heat to help accelerate the ship. If it is too cold, we can turn on an electric heater run by the generator. The air for the generator can come in through a small sort of scoop on top, and leave through a small opening in the rear. The vacuum at the tail will assure us a very rapid circulation, even if the centrifugal pump action of the enclosed generator isn't enough."

His thoughts began moving more rapidly than his words. "We'll want the generator greatly over power to run tests over a greater range. Won't need more than one hundred kilowatts altogether, but should install about a thousand—A.C., of course. Batteries in the keel for starting the generator.... Self-supporting when it's rolling....

"But let's set down some actual figures on this."

For the rest of the day the three men were working on the general plan of the new ship, calculating the strengths needed, supplementing mathematics with actual experiments with the machines on hand. The calculating machines were busy continuously, for there were few rules that experience could give them. They were developing something entirely new, and though they were a designing staff of three of the foremost mathematicians in the world, it was a problem that tested their ingenuity to the utmost.

By the evening of the first day, however, they had been able to give the finished designs for the power units to the mechanics who were to make them. The order for the storage battery and the standard electrical equipment had been placed at once. By the time they had completed the drawings for the mail casting, the materials were already being assembled in a little private camp that Morey owned, up in the hills of Vermont. The giant freight helicopters could land readily in the wide field that had been cleared on the small plateau, in the center of which nestled a little blue lake and a winding trout brook.

The mechanics and electrical engineers had been sent up there already—officially on vacation. The entire program could be carried out without attracting the least attention, for such orders from the great Transcontinental lines were so frequent that no importance was attached to them.

Four days after the final plans had been completed the last of the supplies were being assembled in the portable metal shed that was to house the completed machine. The shining tungsto-steel alloy frame members were rapidly being welded in place by cathode ray welding torches in the hands of skilled artisans.

Already at the other end of the shop the generator had been arranged for use with the molecular motion power units. The many power units to drive and support the ship were finished and awaiting installation as the crew quit work on the fourth evening. They would be installed on the frame in the morning, and the generator would be hoisted into place with the small portable crane. The storage batteries were connected, and in place in the hull. The great fused quartz windows rested in their cases along one wall, awaiting the complete application of the steel alloy plates. They were to be over an inch thick, an unnecessary thickness, perhaps, but they had no need to economize weight, as witnessed by their choice of steel instead of light metal alloys throughout the construction.

The three men had arrived late that afternoon in a small helicopter, and had gone directly to the shops to see what progress had been made. They had been forced to remain in New York to superintend the shipment of the necessary supplies to the camp site, and since no trouble was anticipated in the making of the steel framework, they had not felt it necessary to come. But now they would be needed to superintend the more delicate work.

"She's shaping up nicely, isn't she?" Arcot gazed at the rapidly rounding frame with a critical eye. Unhindered as they were by the traditional shapes, by wings or other protuberances, they had been able to design a machine of striking beauty. The ship was to retain its natural metallic sheen, the only protection being a coat of "passivity paint"—a liquid chemical that could be brushed or sprayed on iron, chromium, nickel or cobalt alloys, rendering them passive to practically all chemical agents. The new "paint" left the iron or steel as brilliantly glossy as ever, but overcast with a beautiful iridescence, and immune to the most powerful reagents.

The three men walked around the rapidly growing hull, and looked with excited interest at the heavy welded joints and the great beams. The ship seemed capable of withstanding a fall of several hundred feet with little damage. The location of the power units was plainly visible and easily recognized, for at each point there came together four or five great beams, welded into one great mass of tough metal, and in it there were set heavy tungsten bolts that would hold the units in place.

They inspected each joint minutely for signs of flaws, using a small portable X-ray fluoroscope to see the interior of the metal. Each joint seemed perfect. They retired, satisfied that everything was ready for the work of the next day.

The morning began early with a long swim in the lake, and a hearty breakfast of country cured ham and eggs. Then the work on the great framework was continued, and that day saw the power units bolted in place, removable if change was thought advisable. Each power unit was equipped with long streamlined copper fins lying close to the rounded hull, that they might absorb heat more rapidly.

Day by day the structure drew nearer completion, and, with the large crew of highly skilled workers, the craft was practically complete within a week. Only the instruments remained to be installed. Then at last even these had been put in place, and with the aid of Fuller, Morey junior, and his own father, Arcot had connected their many complicated circuits.

"Son," remarked Arcot senior, looking critically at the great switchboard, with its maze of connections, its many rheostats and controls, and its heavy bus bar connectors behind it, "no one man can keep an eye on all those instruments. I certainly hope you have a good-sized crew to operate your controls! We've spent two days getting all those circuits together, and I'll admit that some of them still have me beat. I don't see how you intend to watch all those instruments, and at the same time have any idea what's going on outside."

"Oh," laughed Arcot junior, "these aren't intended for constant watching. They're merely helps in a lot of tests I want to make. I want to use this as a flying laboratory so I can determine the necessary powers and the lowest factor of safety to use in building other machines. The machine is very nearly completed now. All we need is the seats—they are to be special air-inflated gyroscopically controlled seats, to make it impossible for a sudden twist of the ship to put the strain in the wrong direction. Of course the main gyroscopes will balance the ship laterally, horizontally, and vertically, but each chair will have a separate gyroscopic mounting for safety."

"When do you expect to start after the Pirate?" Fuller asked.

"I plan to practice the manipulation of the machine for at least four days," Arcot replied, "before I try to chase the Pirate. I'd ordinarily recommend the greatest haste, but the man has stolen close to ten million already, and he's still at it. That would not be done by anyone in his right mind. I suppose you've heard, the War Department considers his new gas so important that they've obtained a pardon for him on condition they be permitted to have the secret of it. They demand the return of the money, and I have no doubt he has it. I am firmly convinced that he is a kleptomaniac. I doubt greatly if he will stop taking money before he is caught. Therefore it will be safe to wait until we can be sure of our ability to operate the machine smoothly. Any other course would be suicidal. Also, I am having some of those tool-makers make up a special type of molecular motion machine for use as a machine gun. The bullets are steel, about three inches long, and as thick as my thumb. They will be perfectly streamlined, except for a little stabilizer at the tail, to guide 'em. They won't spin as a rifle bullet does, and so there will be no gyroscopic effect to hold them nose on, but the streamlining and the stabilizer will keep them on their course. I expect them to be able to zip right through many inches of armour plate, since they will have a velocity of over four miles a second.

"They'll be fed in at the rate of about two hundred a minute—faster if I wish, and started by a small spring. They will instantly come into the field of a powerful molecular motion director, and will be shot out with terrific speed. It will be the first rifle ever made that could shoot bullets absolutely parallel to the ground.

"But that is all we can do today. The guns will be mounted outside, and controlled electrically, and the charts will be installed tomorrow. By the day after tomorrow at eight A.M. I plan to take off!"

The work the next day was rushed to completion far earlier than Arcot had dared to hope. All the men had been kept isolated at the farm, lest they accidentally spread the news of the new machine. It was with excited interest that they helped the machine to completion. The guns had not been mounted as yet, but that could wait. Mid-afternoon found the machine resting in the great construction shed, completely equipped and ready to fly!

"Dick," said Morey as he strode up to him after testing the last of the gyroscopic seats, "she's ready! I certainly want to get her going—it's only three-thirty, and we can go around to the sunlight part of the world when it gets dark at the speeds we can travel. Let's test her now!"

"I'm just as anxious to start as you are, Bob. I've sent for a U.S. Air Inspector. As soon as he comes we can start. I'll have to put an 'X' license indication on her now. He'll go with us to test it—I hope. There will be room for three other people aboard, and I think you and Dad and I will be the logical passengers."

He pointed excitedly. "Look, there's a government helicopter coming. Tell the men to get the blocks from under her and tow her out. Two power trucks should do it. Get her at least ten feet beyond the end of the hangar. We'll start straight up, and climb to at least a five mile height, where we can make mistakes safely. While you're tending to that, I'll see if I can induce the Air Inspector to take a trip with us."

Half an hour later the machine had been rolled entirely out of the shed, on the new concrete runway.

The great craft was a thing of beauty shimmering in the bright sunlight The four men who were to ride in it on its maiden voyage stood off to one side gazing at the great gleaming metal hull. The long sweeping lines of the sides told a story of perfect streamlining, and implied high speed, even at rest. The bright, slightly iridescent steel hull shone in silvery contrast to the gleaming copper of the power units' heat-absorption fins. The great clear windows in the nose and the low, streamlined air intake for the generator seemed only to accentuate the graceful lines of the machine.

"Lord, she's a beauty, isn't she, Dick!" exclaimed Morey, a broad smile of pleasure on his face.

"Well, she did shape up nicely on paper, too, didn't she. Oh, Fuller, congratulations on your masterpiece. It's even better looking than we thought, now the copper has added color to it. Doesn't she look fast? I wish we didn't need physicists so badly on this trip, so you could go on the first ride with us."

"Oh, that's all right, Dick, I know the number of instruments in there, and I realize they will mean a lot of work this trip. I wish you all luck. The honor of having designed the first ship like that, the first heavier-than-air ship that ever flew without wings, jets, or props—that is something to remember. And I think it's one of the most beautiful that ever flew, too."

"Well, Dick," said his father quietly, "let's get under way. It should fly—but we don't really know that it will!"

The four men entered the ship and strapped themselves in the gyroscopic seats. One by one they reported ready.

"Captain Mason," Arcot explained to the Air Inspector, "these seats may seem to be a bit more active than one generally expects a seat to be, but in this experimental machine, I have provided all the safety devices I could think of. The ship itself won't fall, of that I am sure, but the power is so great it might well prove fatal to us if we are not in a position to resist the forces. You know all too well the effect of sharp turns at high speed and the results of the centrifugal force. This machine can develop such tremendous power that I have to make provision for it.

"You notice that my controls and the instruments are mounted on the arm of the chair really; that permits me to maintain complete control of the ship at all times, and still permits my chair to remain perpendicular to the forces. The gyroscopes in the base here cause the entire chair to remain stable if the ship rolls, but the chair can continue to revolve about this bearing here so that we will not be forced out of our seats. I'm confident that you'll find the machine safe enough for a license. Shall we start?"

"All right, Dr. Arcot," replied the Air Inspector. "If you and your father are willing to try it, I am."

"Ready, Engineer?" asked Arcot.

"Ready, Pilot!" replied Morey.

"All right—just keep your eye on the meters, Dad, as I turn on the system. If the instruments back there don't take care of everything, and you see one flash over the red mark—yank open the main circuit. I'll call out what to watch as I turn them on."

"Ready son."

"Main gyroscopes!" There was a low snap, a clicking of relays in the rear compartment, and then a low hum that quickly ran up the scale. "Main generators!" Again the clicking switch, and the relays thudding into action, again the rising hum. "Seat-gyroscopes." The low click was succeeded by a quick shrilling sound that rose in moments above the range of hearing as the separate seat-gyroscopes took up their work. "Main power tube bank!" The low hum of the generator changed to a momentary roar as the relays threw on full load. In a moment the automatic controls had brought it up to speed.

"Everything is working perfectly so far. Are we ready to start now, son?"

"Main vertical power units!" The great ship trembled throughout its length as the lift of the power units started. A special instrument had been set up on the floor beside Arcot, that he might be able to judge the lift of his power units; it registered the apparent weight of the ship. It had read two hundred tons. Now all eyes were fixed on it, as the pointer dropped quickly to 150-100-75-50-40-20-10—there was a click and the instrument flopped back to 300—it was registering in pounds now! Then the needle moved to zero, and the mighty structure floated into the air, slowly moving down the field as a breeze carried it along the ground.

The men outside saw it rise swiftly into the sky, straight toward the blue vault of heaven. In two or three minutes it was disappearing. The glistening ship shrank to a tiny point of light; then it was gone! It must have been rising at fully three hundred miles an hour!

To the men in the car there had been a tremendous increase in weight that had forced them into the air cushions like leaden masses. Then the ground fell away with a speed that made them look in amazement. The house, the construction shed, the lake, all seemed contracting beneath them. So quickly were they rising that they had not time to adjust their mental attitude. To them all the world seemed shrinking about them.

Now they were at a tremendous height; over twenty miles they had risen into the atmosphere; the air about them was so thin that the sky seemed black, the stars blazed out in cold, unwinking glory, while the great fires of the sun seemed reaching out into space like mighty arms seeking to draw back to the parent body the masses of the wheeling planets. About it, in far flung streamers of cold fire shone the mighty zodiacal light, an Aurora on a titanic scale. For a moment they hung there, while they made readings of the meters.

Arcot was the first to speak and there was awe in his voice. "I never began to let out the power of this thing! What a ship! When these are made commercially, we'll have to use about one horsepower generators in them, or people will kill themselves trying to see how fast they can go."

Methodically the machine was tried out at this height, testing various settings of the instruments. It was definitely proven that the values that Arcot and Morey had assigned from purely theoretical calculations were correct to within one-tenth of one percent. The power absorbed by the machine they knew and had calculated, but the terrific power of the driving units was far beyond their expectations.

"Well, now we're off for some horizontal maneuvers," Arcot announced. "I'm sure we agree the machine can climb and can hold itself in the air. The air pressure controls seem to be working perfectly. Now we'll test her speed."

Suddenly the seats swung beneath them; then as the ship shot forward with ever greater speed, ever greater acceleration, it seemed that it turned and headed upward, although they knew that the main stabilizing gyroscopes were holding it level. In a moment the ship was headed out over the Atlantic at a speed no rifle bullet had ever known. The radio speedometer needle pushed farther and farther over as the speed increased to unheard of values. Before they left the North American shoreline they were traveling faster than a mile a second. They were in the middle of the Atlantic before Arcot gradually shut off the acceleration, letting the seats drop back into position.

A hubbub of excited comments rose from the four men. Momentarily, with the full realization of the historical importance of this flight, no one paid any attention to anyone else. Finally a question of the Air Inspector reached Arcot's ears.

"What speed did we attain, Dr. Arcot? Look—there's the coast of Europe! How fast are we going now?"

"We were traveling at the rate of three miles a second at the peak." Arcot answered. "Now it has fallen to two and a half."

Again Arcot turned his attention to his controls. "I'm going to try to see what the ultimate ceiling of this machine is. It must have a ceiling, since it depends on the operation of the generator to operate the power-units. This, in turn, depends on the heat of the air, helped somewhat by the sun's rays. Up we go!"

The ship was put into a vertical climb, and steadily the great machine rose. Soon, however, the generator began to slow down. The readings of the instruments were dropping rapidly. The temperature of the exceedingly tenuous air outside was so close to absolute zero that it provided very little energy.

"Get up some forward speed," Morey suggested, "so that you'll have the aid of the air scoop to force the air in faster."

"Right, Morey." Arcot slowly applied the power to the forward propulsion units. As they took hold, the ship began to move forward. The increase in power was apparent at once. The machine started rising again. But at last, at a height of fifty-one miles, her ceiling had been reached.

The cold of the cabin became unbearable, for every kilowatt of power that the generator could get from the air outside was needed to run the power units. The air, too, became foul and heavy, for the pumps could not replace it with a fresh supply from the near-vacuum outside. Oxygen tanks had not been carried on this trip. As the power of the generator was being used to warm the cabin once more, they began to fall. Though the machine was held stable by the gyroscopes, she was dropping freely; but they had fifty miles to fall, and as the resistance of the denser air mounted, they could begin to feel the sense of weight return.

"You've passed, but for the maneuvers, Dr. Arcot!" The Air Inspector was decidedly impressed. "The required altitude was passed so long ago—why we are still some miles above it, I guess! How fast are we falling?"

"I can't tell unless I point the nose of the ship down, for the apparatus works only in the direction in which the ship is pointed. Hold on, everyone, I am going to start using some power to stop us."

It was night when they returned to the little field in Vermont. They had established a new record in every form of aeronautical achievement except endurance! The altitude record, the speed record, the speed of climb, the acceleration record—all that Arcot could think of had been passed. Now the ship was coming to dock for the night. In the morning it would be out again. But now Arcot was sufficiently expert with the controls to maneuver the ship safely on the ground. They finally solved the wind difficulty by decreasing the weight of the ship to about fifty pounds, thus enabling the three men to carry it into the hanger!

* * * * *

The next two days were devoted to careful tests of the power factors of the machine, the best operating frequency, the most efficient altitude of operation, and as many other tests as they had time for. Each of the three younger men took turns operating, but so great were the strains of the sudden acceleration, that Arcot senior decided it would be wisest for him to stay on the ground and watch.

In the meantime reports of the Pirate became fewer and fewer as less and less money was shipped by air.

Arcot spent four days practicing the manipulation of the machine, for though it handled far more readily than any other craft he had ever controlled, there was always the danger of turning on too much power under the stress of sudden excitement.

The night before, Arcot had sailed the ship down and alighted on the roof of Morey senior's apartment, leaving enough power on to reduce the weight to but ten tons, lest it fall through the roof, while he went down to see the President of the Lines about some "bait" for the Pirate.

"Send some cash along," said Arcot, when he saw Morey senior, "say a quarter of a million. Make it more or less public knowledge, and talk it up so that the Pirate may think there's a real haul on board. I am going to accompany the plane at a height of about a quarter of a mile above. I will try to locate him from there by means of radar, and if I have my apparatus on, I naturally can't locate him. I hope he won't be scared away—but I rather believe he won't. At any rate, you won't lose on the try!"



IV

Again Morey and Arcot were looking at the great Jersey aerodrome, out on the fields that had been broad marshes centuries before. Now they had been filled in, and stretched for miles, a great landing field, close to the great city across the river.

The men in the car above were watching the field, hanging inert, a point of glistening metal, high in the deep velvet of the purple sky, for fifteen miles of air separated them from the Transcontinental machine below. Now they saw through their field glasses that the great plane was lumbering slowly across the field, gaining momentum as it headed westward into the breeze. Then it seemed to be barely clearing the great skyscrapers that towered twenty-four hundred feet into the air, arching over four or five city blocks. From this height they were toys made of colored paper, soft colors glistening in the hot noon sunlight, and around and about them wove lines of flashing, moving helicopters, the individual lost in the mass of the million or so swiftly moving machines. Only the higher, steadily moving levels of traffic were visible to them.

"Just look at that traffic! Thousands and thousands coming back into the city after going home to lunch—and every day the number of helicopters is increasing! If it hadn't been for your invention of this machine, conditions would soon be impossible. The airblast in the cities is unbearable now, and getting worse all the time. Many machines can't get enough power to hold themselves up at the middle levels; there is a down current over one hundred miles an hour at the 400-foot level in downtown New York. It takes a racer to climb fast there!

"If it were not for gyroscopic stabilizers, they could never live in that huge airpocket. I have to drive in through there. I'm always afraid that somebody with an old worn-out bus will have stabilizer failure and will really smash things." Morey was a skillful pilot, and realized, as few others did, the dangers of that downward airblast that the countless whirring blades maintained in a constant roar of air. The office buildings now had double walls, with thick layers of sound absorbing materials, to stop the roar of the cyclonic blast that continued almost unabated twelve hours a day.

"Oh, I don't know about that, Morey," replied Arcot. "This thing has some drawbacks. Remember that if we had about ten million of these machines hung in the air of New York City, there would be a noticeable drop in the temperature. We'd probably have an Arctic climate year in and year out. You know, though, how unbearably hot it gets in the city by noon, even on the coldest winter days, due to the heating effect of the air friction of all those thousands of blades. I have known the temperature of the air to go up fifty degrees. There probably will have to be a sort of balance between the two types of machines. It will be a terrific economic problem, but at the same time it will solve the difficulties of the great companies who have been fermenting grain residues for alcohol. The castor bean growers are also going to bring down their prices a lot when this machine kills the market. They will also be more anxious to extract the carbon from the cornstalks for reducing ores of iron and of other metals."

As the ship flew high above the Transcontinental plane, the men discussed the economic values of the different applications of Arcot's discoveries from the huge power stations they could make, to the cooling and ventilating of houses.

"Dick, you mentioned the cooling effect on New York City; with the millions on millions of these machines that there will be, with huge power plants, with a thousand other different applications in use, won't the terrific drain of energy from the air cause the whole world to become a little cooler?" asked Fuller.