The Black Star Passes

by Jr. John W. Campbell

SOLARITE

I

The lights of great Transcontinental Airport were blazing in cheering splendor. Out there in the center of the broad field a dozen men were silhouetted in the white brilliance, looking up at the sky, where the stars winked cold and clear on the jet background of the frosty night. A slim crescent of moon gleamed in the west, a sickle of light that in no way dimmed the cold flame of the brilliant stars.

One point of light now moved across the motionless field of far-off suns, flashing toward the airport in a long, swift curve. The men on the field murmured and pointed up at it as it swept low over the blazing lights of New York. Lower it swooped, the towering city behind it. Half a mile into the air the buildings rose in shining glory of colored tile that shone brightly in the sweeping play of floodlights.

One of them picked out the descending machine, and it suddenly leaped out of the darkness as a shining, streamlined cylinder, a cylinder with a great halo of blue fire, as the beam of the searchlight set it off from the jet black night.

In moments the ship was vast before the eyes of the waiting men; it had landed gently on the field, was floating smoothly, gracefully toward them.

Twenty-four men climbed from the great ship, shivering in the icy blast that swept across the field, spoke a moment with the group awaiting their arrival, then climbed quickly into the grateful warmth of a field car. In a moment they were speeding toward the lights of the field house, half a mile off.

Behind them the huge ship leaped into the sky, then suddenly pointed its nose up at an angle of thirty degrees and shot high into the air at an unbelievable speed. In an instant it was gone.

At the field house the party broke up almost immediately.

“We want to thank you, Mr. Morey, for your demonstration of the new ship tonight, and you, Dr. Arcot, for answering our many questions about it. I am sure we all appreciate the kindness you have shown the press.” The reporters filed out quickly, anxious to get the news into the morning editions, for it was after one o'clock now. Each received a small slip of paper from the attendant standing at the exit, the official statement of the company. At last all had left but the six men who were responsible for the new machine.

This night had witnessed the official demonstration of the first of the Arcot-Morey molecular motion ships. Small as she was, compared to those that were to come, yet she could carry over three thousand passengers, as many as could any existing winged plane, and her speed was immensely greater. The trip from the west coast to the eastern had been made in less than one hour. At a speed close to one mile a second the great ship had shot through the thin air, twenty-five miles above the Earth.

In this vessel a huge bar of metal could be affected by an ultra-high-frequency generator. When so affected, its molecules all moved forward, taking the ship with them. Thus, a molecular motion drive vessel could, theoretically, approach the velocity of light as a limit.

“Arcot,” said Morey, Senior, after the pressmen had left the room, “as president of this company I certainly want to thank you for the tremendous thing you have given us to use. You have 'sold' us this machine—but how can we repay you? Before this, time and time again, you have sold us your inventions, the ideas that have made it possible for Transcontinental to attain its present high position in world transportation. All you have ever accepted is the laboratory you use, its upkeep, and a small annual income. What can we do to show our appreciation this time?”

“Why,” answered Arcot smiling, “you haven't stated the terms correctly. Actually, I have a fully equipped lab to putter around in, all the time I want for my own amusement, and all the money I want. What more could I ask?”

“I suppose that's all true—but you draw only about six thousand a year for personal expenses—a good clerk could get that—and you, admittedly the most brilliant physicist of the Earth, are satisfied! I don't feel we're paying you properly!”

Arcot's expression became suddenly serious. “You can repay me this time,” he said, “for this latest discovery has made a new thing possible. I've always wanted to be able to visit other planets—as has many a scientist for the last three centuries. This machine has made it possible. If you are willing—we could start by the spring of 2117. I'm quite serious about this. With your permission, I want to start work on the first interplanetary ship. I'll need Fuller's help, of course. The proposition will be expensive, and that's where I must ask you to help me. I think, however, that it may be a paying proposition, at that, for there will certainly be something of commercial value on the other planets.”

They had walked out to the shed where Arcot's private molecular motion car stood, the first machine ever built that used the heat of the sun to drive it. Thoughtfully the president of the great Transcontinental Lines looked at it. It was small compared with the great machine that had just brought them east, but of the same swift type. It was a thing of graceful beauty even on the ground, its long curving streamlines giving it wonderful symmetry. They stood in thoughtful silence for a minute—the young men eager to hear the verdict of their prospective backer. Morey, always rather slow of speech, took an unusually long time to answer.

“If it were only money you asked for, Arcot, I'd gladly give you double the sum, but that isn't the case. I know perfectly well that if you do go, my son will go with you, and Fuller and Wade will naturally go too.” He looked at each in turn. “Each of you has come to mean a lot to me. You and Fuller have known Bob since college days. I've known Wade only three months, but every day I grow to like him more. There's no denying the fact that any such trip is a terrifically dangerous proposition. But if you were lost, there would be more than my personal loss. We would lose some of the most brilliant men on Earth. You, for instance, are conceded as being the world's most brilliant physicist; Fuller is one of the greatest designing engineers; Wade is rapidly rising into prominence as a chemist and as a physicist; and my son is certainly a good mathematician.”

He paused, frowning, weighing the situation. “But you men should know how to get out of scrapes just that much better. Certainly there are few men on Earth who would not be willing to back such a group of men—or any one of you, for that matter! I'll back your trip!” His words became more facetious. “I know that Arcot and you, Bob, can handle a gun fairly well, I don't know so much about Wade and Fuller. What experience have you two had?”

Fuller shook his head. “I think I'll fit best in the galley on the trip, Mr. Morey. I've done the cooking on a number of camping trips, and food is an important factor in the success of any expedition. I can shoot a bit, too.”

Wade spoke rather hesitantly. “I come from the west, and have had a good bit of fun with a gun in the Rockies; there are still some mountain lions and some deer there, you know. I also have a sneaking acquaintance with the new gun, which Arcot developed in connection with his molecular motion. But there is so little you know about me—and most of it bad—I don't see how I really get in on this opportunity—but,” he added hastily, “I certainly don't intend to keep the old boy knocking—I'm with you, since I'm invited!”

Arcot smiled. “Then you'll definitely support us?”

“Yes, I will,” replied Morey, Senior, seriously, “for I think it's worth doing.”

The four young men climbed into the ship, to start for their apartment. Arcot was piloting, and under his sure touch the ship sped out into the cold night air, then up through the atmosphere, till they hung poised at a height of fifty miles on the upper edge of the airy blanket. They looked out in silent thought at the magnificent blazing stars of space. Here, where the dust-laden air could no longer mask their true colors, the stars shone unwinkingly, steadily, and in a glory that earth-bound men had never seen before. They shone in a wonderous riot of color, as varied and as beautiful as the display of colored floodlights in some great city. They were tiny pinpoints of radiance, red, green, orange, and yellow, shining with intense brilliance.

Slowly Arcot let the machine settle to the blazing city miles below.

“I love to come out here and look at those cold, pinpoint lights; they seem to draw me—the lure of other worlds. I've always had a sense of unfulfilled longing—the desire to go out there—and it's always been so hopeless. Now—I'll be out there by next spring!” Arcot paused and looked up at the mighty field of stars that arched over his head to be lost on either horizon. A wonderful night!

“Where shall we go first, Dick?” asked Wade softly as he gazed out at the far-off suns of space, his voice unconsciously hushed by the grandeur of the spectacle.

“I've thought of that for the last four months, and now that we are definitely going to go, we'll have to make a decision. Actually, it won't be too hard to decide. Of course we can't leave the solar system. And the outer planets are so far away that I think we had better wait till later trips. That leaves the choice really between Mars, Venus, and Mercury. Mercury isn't practical since it's so close to the sun. We know a fair bit about Mars from telescopic observation, while Venus, wrapped in perpetual cloud, is a mystery. What do you vote?”

“Well,” said Morey, “it seems to me it's more fun to explore a completely unknown planet than one that can be observed telescopically. I vote Venus.” Each of the others agreed with Morey that Venus was the logical choice.

By this time the machine had sunk to the roof of their apartment, and the men disembarked and entered. The next day they were to start the actual work of designing the space ship.

---

II

“When we start this work,” Arcot began next morning, “we obviously want to design the ship for the conditions we expect to meet, and for maximum convenience and safety. I believe I've thought about this trip longer than the rest of you, so I'll present my ideas first.

“We don't actually know anything about conditions on Venus, since no one has actually been there. Venus is probably a younger planet than Earth. It's far nearer the sun than we are, and it gets twice the heat we do. In the long-gone time when the planets were cooling I believe Venus required far longer than Earth, for the inpouring heat would retard its cooling. The surface temperature is probably about 150 degrees Fahrenheit.

“There is little land, probably, for with the cloud-mass covering Venus as it does, it's logical to visualize tremendous seas. What life has developed must be largely aquatic, and the land is probably far behind us in evolution. Of course, Venus is the planet of mystery—we don't know; we can only guess. But we do know what things we are going to need to cross space.

“Obviously, the main driving force will be the power units. These will get their energy from the rays of the sun by absorbing them in copper discs about twelve feet in diameter—the ship will have to be more of a disc than a cylinder. I think a ship a hundred and eighty feet long, fifty feet wide, and twenty feet deep will be about the best dimensions. The power units will be strung along the top of the ship in double rows—one down each side of the hull. In the middle will be a series of fused quartz windows, opening into a large room just under the outer shell. We'll obviously need some source of power to activate the power tubes that run the molecular motion power units. We'll have a generator run by molecular motion power units in here, absorbing its heat from the atmosphere in this room. The air will be heated by the rays of the sun, of course, and in this way we'll get all our power from the sun itself.

“Since this absorption of energy might result in making the ship too cool, due to the radiation of the side away from the sun, we'll polish it, and thus reduce the unlighted side's radiation.

“The power units will not be able to steer us in space, due to their position, and those on the sides, which will steer us in the atmosphere by the usual method, will be unable to get the sun's power; they'll be shaded. For steering in space, we'll use atomic hydrogen rockets, storing the atomic gas by the Wade method in tanks in the hold. We'll also have a battery down there for starting the generator and for emergencies.

“For protection against meteors, we'll use radar. If anything comes within a dozen miles of us, the radar unit covering that sector will at once set automatic machinery in operation, and the rockets will shoot the ship out of the path of the meteor.”

All that day Arcot and the others discussed the various pieces of apparatus they would need, and toward evening Fuller began to draw rough sketches of the different mechanisms that had been agreed upon.

The next day, by late afternoon, they had planned the rough details of the ship and had begun the greater task of calculating the stresses and the power factors.

“We won't need any tremendous strength for the ship while it is in space,” Arcot commented, “for then there will be little strain on it. It will be weightless from the start, and the gentle acceleration will not strain it in the least, but we must have strength, so that it can maneuver in the atmosphere.

“We'll leave Earth by centrifugal force, for I can make much better speed in the atmosphere where there is plenty of power to draw on; outside I must depend solely on sunlight. We'll circle the Earth, forming an orbit just within the atmosphere, at five miles a second. We'll gradually increase the speed to about ten miles a second, at which point the ship would normally fly off into space under its own centrifugal force. With the power units we'll prevent its release until the proper moment. When we release it, it will be entirely free of Earth, and no more work will be needed to overcome Earth's pull.”

The planning continued with exasperating slowness. The details of the work were complex, for all the machines were totally new. Several weeks passed before even the power units could be ordered and the first work on the ship started. After that orders for materials left the office daily. Still, it was late in November before the last order was sent out.

Now they must begin work on other phases of the expedition—food supplies and the standard parts of the equipment.

In the interval Arcot had decided to make a special ventilated suit for use on Venus. This was to make use of a small molecular motion director apparatus to cool the air, and blow it through the suit. The apparatus consisted of a small compressed air-driven generator and a power tube bank that could be carried on the back.

“Arcot,” Wade said when he saw the apparatus completed and the testing machine ready, “I've just noticed how similar this is to the portable invisibility apparatus I developed as the Pirate. I wonder if it might not be handy at times to be invisible—we could incorporate that with a slight change. It wouldn't add more than five pounds, and those tubes you are using I'm sure are easily strong enough to carry the extra load.”

“Great idea, Wade,” said Arcot. “It might be very useful if we met hostile natives. The disappearance stunt might make us gods or something to primitive beings. And now that you mention it, I think we can install the apparatus in the ship. It will require almost no power, and might save our lives some time.”

The work went forward steadily at the great Transcontinental Shops where the space ship was being built. Its construction was being kept as much of a secret as possible, for Arcot feared the interference of the crowds that would be sure to collect if the facts were known, and since the shops directly joined the airfield, it meant that there would be helicopters buzzing about the Transatlantic and Transcontinental planes.

The work to be done required the most careful manipulation and workmanship, for one defect could mean death. They calculated six weeks for the trip, and in the time before they could reach either planet, much might happen to a crippled ship.

To the men who were making the trip, the waiting seemed most exasperating, and they spent the days before they could begin the installation of the electrical apparatus in purchasing the necessary standard equipment; the standard coils, tubes, condensers, the canned food supplies, clothes, everything that they could imagine as of possible utility. They were making the ship with a great deal of empty storage space, for Arcot hoped the trip would be a financial success, particularly supplying much-needed metals. Many vital elements were already excessively scarce, and no satisfactory substitutes had been found.

On the outward trip some of this space would be filled with the many things they would consume en route. In addition they were carrying a great many spare parts, spare tubes, spare power units, spare condensers—a thousand and one odd parts. Arcot intended that they should be able to make an entire new power switchboard and motion director unit if anything should go wrong, and he certainly had all the apparatus.

At last came the day when the final connection had been soldered, and the last joint welded. The atomic hydrogen tanks were full, and under the ship's own power the oxygen tanks were filled and the batteries charged. They were ready for a test flight!

The great ship rested on the floor of the shed now, awaiting the start.

“Oh fellows—come here a minute!” Arcot called to the other members of the party. “I want to show you something.”

The three walked quickly to the bow where Arcot stood, and following the line of his vision, looked in wonder to see that everything was right. They watched curiously as he drew from his coat a large glass bottle, tightly sealed.

“What's that for?” asked Wade curiously.

“We're about to start on the first cruise, and I've been wondering if it isn't time we gave the ship a name.”

“Great—I'd been thinking of that too—what are we going to name her?”

“Well,” said Arcot, “I had been thinking of Alexander—he longed for other worlds to conquer!”

“Not bad,” Morey commented. “I have been thinking of naming it too—I guess we all have—but I was thinking of Santa Maria—the first ship to discover the New World.”

“I was think more of its home,” said Wade. “How about calling it Terrestrian?”

“Well—it's your turn, Fuller—you designed it. What do you suggest for your masterpiece?” asked Arcot.

“I was thinking also of its home—the home it will never leave. I like to think that we might find people on Venus, and I would like to have a name on it that might be translatable into more friendly and less foreign terms—why not call it Solarite?”

“Solarite—a member of the solar system—it will be that, always. It will be a world unto itself when it makes its trips—it will take up an orbit about the sun—a true member of the solar system. I like it!” Arcot turned to the others. “How about it?” It was agreed upon unanimously.

“But I'm still curious about that glass bottle, so carefully sealed.” Morey commented with a puzzled smile. “What's in it? Some kind of gas?”

“Wrong—no gas—practically nothing at all, in fact. What more appropriate for christening a space ship than a bottle of hard vacuum?

“We can't have a pretty girl christen this ship, that's sure. A flying bachelor's apartment christened by a mere woman? Never! We will have the foreman of the works here do that. Since we can't have the ship slide down the ways or anything, we will get inside and move it when he smashes the bottle. But in the meantime, let's have a symbol set in contrasting metal on the bow. We can have a blazing sun, with nine planets circling it, the Earth indicated conspicuously; and below it the word SOLARITE.”

---

III

It was shortly after noon when the newly christened Solarite left on its first trip into space. The sun was a great ball of fire low in the west when they returned, dropping plummet-like from the depths of space, the rush of the air about the hull, a long scream that mounted from a half-heard sound in the outer limits of the Earth's atmosphere, to a roar of tortured air as the ship dropped swiftly to the field and shot into the hangar. Instantly the crew darted to the side of the great cylinder as the door of the ship opened.

Fuller appeared in the opening, and at the first glimpse of his face, the hangar crew knew something was wrong. “Hey, Jackson,” Fuller called, “get the field doctor—Arcot had a little accident out there in space!” In moments the man designated returned with the doctor, leading him swiftly down the long metal corridor of the Solarite to Arcot's room aboard.

There was a mean-looking cut in Arcot's scalp, but a quick, sure examination by the doctor revealed that there appeared to be no serious injury. He had been knocked unconscious by the blow that made the cut, and he had not yet recovered his senses.

“How did this happen?” asked the doctor as he bathed the cut and deftly bandaged it.

Morey explained: “There's a device aboard whose job it is to get us out of the way of stray meteors, and it works automatically. Arcot and I were just changing places at the controls. While neither of us was strapped into our seats, a meteor came within range and the rocket tubes shot the car out of the way. We both went tumbling head over heels and Arcot landed on his ear. I was luckier, and was able to break my fall with my hands, but it was a mean fall—at our speed we had about double weight, so, though it was only about seven feet, we might as well have fallen fourteen. We took turns piloting the ship, and Arcot was about to bring us back when that shock just about shook us all over the ship. We will have to make some changes. It does its job—but we need warning enough to grab hold.”

The doctor was through now, and he began to revive his patient. In a moment he stirred and raised his hand to feel the sore spot. In ten minutes he was conversing with his friends, apparently none the worse except for a very severe headache. The doctor gave him a mild opiate, and sent him to bed to sleep off the effects of the blow.

---

With the ship fully equipped, tested and checked in every possible way, the time for leaving was set for the following Saturday, three days off. Great supplies of stores had to be carried aboard in the meantime. Care had to be exercised in this work, lest the cargo slip free under varying acceleration of the Solarite, and batter itself to bits, or even wreck some vital part of the ship. At noon on the day chosen, the first ship ever to leave the bounds of the Earth's gravity was ready to start!

Gently the heavily laden Solarite rose from the hangar floor, and slowly floated out into the bright sunshine of the early February day. Beside it rode the little ship that Arcot had first built, piloted by the father of the inventor. With him rode the elder Morey and a dozen newsmen. The little ship was badly crowded now as they rose slowly, high into the upper reaches of the Earth's atmosphere. The sky about them was growing dark—they were going into space!

At last they reached the absolute ceiling of the smaller ship, and it hung there while the Solarite went a few miles higher; then slowly, but ever faster and faster they were plunging ahead, gathering speed.

They watched the radio speedometer creep up—1-2-3-4-5-6—steadily it rose as the acceleration pressed them hard against the back of the seats—8-9—still it rose as the hum of the generator became a low snarl—10-11-12—they were rocketing at twelve miles a second, the tenuous air about the ship shrieking in a thin scream of protest as it parted on the streamlined bow.

Slowly the speed rose—reached fifteen miles a second. The sun's pull became steadily more powerful; they were falling toward the fiery sphere, away from the Earth. A microphone recessed in the outer wall brought them the fading whisper of air from outside. Arcot shouted a sudden warning:

“Hold on—we're going to lose all weight—out into space!”

There was a click, and the angry snarl of the overworked generator died in an instant as the thudding relays cut it out of the circuit. Simultaneously the air scoop which had carried air to the generator switched off, transferring to solar heat as a source of power. They seemed to be falling with terrific and ever-increasing speed. They looked down—saw the Earth shrinking visibly as they shot away at more than five miles a second; they were traveling fifteen miles a second ahead and five a second straight up.

The men watched with intensest interest as the heavens opened up before them—they could see stars now a scant degree from the sun itself, for no air diffused its blinding glory. The heat of the rays seemed to burn them; there was a prickling pleasantness to it now, as they looked at the mighty sea of flame through smoked glasses. The vast arms of the corona reached out like the tentacles of some fiery octopus through thousands of miles of space—huge arms of flaming gas that writhed out as though to reach and drag back the whirling planets to the parent body. All about the mighty sphere, stretching far into space, a wan glow seemed to ebb and flow, a kaleidoscope of swiftly changing color. It was the zodiacal light, an aurora borealis on a scale inconceivable!

Arcot worked rapidly with the controls, the absence of weight that gave that continued sense of an unending fall, aiding him and his assistants in their rapid setting of the controls.

At last the work was done and the ship flashed on its way under the control of the instruments that would guide it across all the millions of miles of space and land it on Venus with unerring certainty. The photo-electric telescopic eye watched the planet constantly, keeping the ship surely and accurately on the course that would get them to the distant planet in the shortest possible time.

Work thereafter became routine requiring a minimum of effort, and the men could rest and use their time to observe the beauties of the skies as no man had ever seen them during all the billions of years of time that this solar system has existed. The lack of atmosphere made it possible to use a power of magnification that no terrestrial telescope may use. The blurred outlines produced by the shifting air prohibits magnifications of more than a few hundred diameters, but here in space they could use the greatest power of their telescope. With it they could look at Mars and see it more clearly than any other man had ever seen it, despite the fact that it was now over two hundred million miles away.

But though they spent much time taking photographs of the planets and of the moon, and in making spectrum analyses of the sun, time passed very slowly. Day after day they saw measured on the clocks, but they stayed awake, finding they needed little sleep, for they wasted no physical energy. Their weightlessness eliminated fatigue. However, they determined that during the twelve hours before reaching Venus they must be thoroughly alert, so they tried to sleep in pairs. Arcot and Morey were the first to seek slumber—but Morpheus seemed to be a mundane god, for he did not reward them. At last it became necessary for them to take a mild opiate, for their muscles refused to permit their tired brains to sleep. It was twelve hours later when they awoke, to relieve Wade and Fuller.

They spent most of the twelve hours of their routine watch in playing games of chess. There was little to be done. The silver globe before them seemed unchanging, for they were still so far away it seemed little larger than the moon does when seen from Earth.

But at last it was time for the effects of the mild drug to wear off, and for Wade and Fuller to awaken from their sleep.

“Morey—I've an idea!” There was an expression of perfect innocence on Arcot's face—but a twinkle of humor in his eyes. “I wonder if it might not be interesting to observe the reactions of a man waking suddenly from sleep to find himself alone in space?” He stared thoughtfully at the control that would make the ship perfectly transparent, perfectly invisible.

“I wonder if it would?” said Morey grasping Arcot's idea. “What do you say we try it?” Arcot turned the little switch—and where there had been the ship, it was no more—it was gone!

Fuller stirred uneasily in his bed, tightly strapped as he was. The effects of the drug were wearing off. Sleepily he yawned—stretched, and blindly, his heavy eyes still closed, released the straps that held him in bed. Yawning widely he opened his eyes—with a sudden start sat upright—then, with an excellent imitation of an Indian on the warpath, he leaped from his bed, and started to run wildly across the floor. His eyes were raised to the place where the ceiling should have been—he called lustily in alarm—then suddenly he was flying up—and crashed heavily against the invisible ceiling! His face was a picture of utter astonishment as he fell lightly to the floor—then slowly it changed, and took on a chagrined smile—he understood!

He spun around as loud cries suddenly resounded from Wade's room across the hall—then there was a dull thud, as he too, forgetting the weightlessness, jumped and hit the ceiling. Then the cries were gone, like the snuffing of a candle. From the control room there rose loud laughter—and a moment later they felt more normal, as they again saw the four strong walls about them.

Wade sighed heavily and shook his head.

They were approaching the planet visibly now. In the twelve hours that had passed they had covered a million miles, for now they were falling toward the planet under its attraction. It glowed before them now in wonderous splendour, a mighty disc of molten silver.

For the last twenty-four hours they had been reducing their speed relative to Venus, to insure their forming an orbit about the planet, rather than shoot around it and back into space. Their velocity had been over a hundred miles a second part of the way, but now it had been reduced to ten. The gravity of the planet was urging them forward at ever increasing speed, and their problem became more acute moment by moment.

“We'll never make it on the power units alone, out here in space,” said Arcot seriously. “We'll just shoot around the planet. I'll tell you how we can do it, though. We'll circle around it, entering its atmosphere on the daylight side, and shoot into the upper limits of its atmosphere. There the power units can find some heat to work on, and we can really slow down. But we'll have to use the rocket tubes to get the acceleration we'll need to drive the ship into the air.”

There was a sudden clanging of a bell, and everyone dived for a hold, and held on tightly. An instant later there was a terrific wrench as the rocket jets threw the plane out of the way of a meteor.

“We're getting near a planet. This is the third meteor we've met since we were more than a million miles from Earth. Venus and Earth and all the planets act like giant vacuum cleaners of space, pulling into themselves all the space debris and meteors within millions of miles by their gravitational attraction.”

Swiftly the planet expanded below them—growing vaster with each passing moment. It had changed from a disc to a globe, and now, as the molten silver of its surface seemed swiftly clouding, it turned grey; then they saw its true appearance, a vast field of rolling, billowing clouds!

The Solarite was shooting around the planet now at ten miles a second, far more than enough to carry them away from the planet again, out into space once more if their speed was not checked.

“Hold on everybody,” Arcot called. “We're going to turn toward the planet now!” He depressed a small lever—there was a sudden shock, and all the space about them seemed to burst into huge, deep-red atomic hydrogen flames.

The Solarite reeled under the sudden pressure, but the heavy gyroscopic stabilizers caught it, held it, and the ship remained on an even keel. Then suddenly there came to the ears of the men a long drawn whine, faint—almost inaudible—and the ship began slowing down. The Solarite had entered the atmosphere of Venus—the first man-made machine to thus penetrate the air of another world!

Quickly Arcot snapped open the control that had kept the rockets flaming, turning the ship to the planet—driving it into the atmosphere. Now they could get their power from the air that each instant grew more dense about them.

“Wade—in the power room—emergency control post—Morey—control board there—hang on, for we'll have to use some husky accelerations.”

Instantly the two men sprang for their posts—literally diving, for they were still almost weightless.

Arcot pulled another lever—there was a dull snap as a relay in the power room responded—the lights wavered—dimmed—then the generator was once more humming smoothly—working on the atmosphere of Venus! In a moment the power units were again operating, and now as they sucked a plentitude of power from the surrounding air, they produced a force that made the men cling to their holds with almost frantic force. Around them the rapidly increasing density of the air made the whine grow to a roar; the temperature within the ship rose slowly, warmed by friction with the air, despite the extreme cold at this altitude, more than seventy-five miles above the surface of the planet.

They began dropping rapidly now—their radio-speedometer had fallen from ten to nine—then slowly, but faster and faster as more heat could be extracted from the air, it had fallen 8—7—6—5—4. Now they were well below orbital speed, falling under the influence of the planet. The struggle was over—the men relaxed. The ship ran quietly now, the smooth hum of the air rushing over the great power units coming softly through the speaker to their ears, a humming melody—the song of a new world.

---

IV

Suddenly the blazing sun was gone and they were floating in a vast world of rolling mists—mists that brushed the car with tiny clicks, which, with the millions of particles that struck simultaneously, merged into a steady roar.

“Ice—ice clouds!” Morey exclaimed.

Arcot nodded. “We'll drop below the clouds; they're probably miles deep. Look, already they're changing—snow now—in a moment it will be water—then it'll clear away and we'll actually see Venus!”

For ten miles—an endless distance it seemed—they dropped through clouds utterly impenetrable to the eye. Then gradually the clouds thinned; there appeared brief clear spots, spots into which they could see short distances—then here and there they caught glimpses of green below. Was it water—or land?

With a suddenness that startled them, they were out of the clouds, shooting smoothly and swiftly above a broad plain. It seemed to stretch for endless miles across the globe, to be lost in the far distance to east and west; but to the north they saw a low range of hills that rose blue and misty in the distance.

“Venus! We made it!” Morey cried jubilantly. “The first men ever to leave Earth—I'm going to start the old sender and radio back home! Man—look at that stretch of plain!” He jumped to his feet and started across the control room. “Lord—I feel like a ton of lead now—I sure am out of condition for walking after all that time just floating!”

Arcot raised a restraining hand. “Whoa—wait a minute there, Morey—you won't get anything through to them now. The Earth is on the other side of Venus—it's on the night side, remember—and we're on the day side. In about twelve hours we'll be able to send a message. In the meantime, take the controls while I make a test of the air here, will you?”

Relieved of the controls, Arcot rose and walked down the corridor to the power room where the chemical laboratory had been set up. Wade had already collected a dozen samples of air, and was working on them.

“How is it—what have you tested for so far?” asked Arcot.

“Oxygen and CO₂. The oxygen is about twenty-two per cent, or considering the slightly lower air pressure here, we will have just about the right amount of oxygen. The CO₂ is about one-tenth of one per cent. The atmosphere is O.K. for terrestrial life apparently; that mouse there is living quite happily. Whatever the other seventy-five per cent or so of diluting gas is, I don't know, but it isn't nitrogen.”

Briefly Arcot and Wade discussed the unusual atmosphere, finally deciding that the inert gas was argon.

“No great amount of nitrogen,” Arcot concluded. “That means that life will have a sweet time extracting it from the air—but wherever there is life, it finds a way to do the impossible. Test it more accurately, will you—you try for nitrogen and I'll try the component inert gasses.”

They ran the analyses rapidly, and in a very short time—less than an hour—their results stood at 23 per cent oxygen, .1 per cent carbon dioxide, 68 per cent argon, 6 per cent nitrogen, 2 per cent helium, 5 per cent neon, .05 per cent hydrogen, and the rest krypton and xenon apparently. The analyses of these inert gasses had to be done rather roughly in this short time, but it was sufficient to balance fairly accurately.

The two chemists reported back to the control cabin.

“Well, we'll be able to breathe the atmosphere of Venus with ease. I believe we can go on now. I have been surprised to see no water in sight, but I think I see my mistake now. You know the Mississippi has its mouth further from the center of the Earth than its source; it flows up hill! The answer is, of course, that the centrifugal force of the Earth's spin impels it to flow that way. Similarly, I am sure now that we will find that Venus has a vast belt of water about the middle, and to the north and south there will be two great caps of dry land. We are on the northern cap.

“We have the microphone turned way down. Let's step up the power a bit and see if there are any sounds outside,” said Arcot and walked over to the power control switch. An instant later a low hum came from the loudspeaker. There was a light breeze blowing. In the distance, forming a dull background for the hum, there came a low rumbling that seemed punctuated now and then by a greater sound.

“Must be a long way off,” said Arcot, a puzzled frown on his face. “Swing the ship around so we can see in what direction the sound is loudest,” he suggested.

Slowly Morey swung the ship around on its vertical axis. Without a doubt, something off in the direction of the hills was making a considerable noise.

“Arcot, if that's a fight between two animals—two of those giant animals that you said might be here—I don't care to get near them!” Fuller's narrowed eyes strove to penetrate the haze that screened the low hills in the blue distance.

The microphone was shut off while the Solarite shot swiftly forward toward the source of the sound. Quickly the hills grew, the blue mistiness disappearing, and the jagged mounds revealing themselves as bleak harsh rock. As they drew nearer they saw beyond the hills, intermittent flashes of brilliant light, heard shattering blasts of sound.

“A thunderstorm!” Wade began, but Arcot interrupted.

“Not so fast, Wade—Fuller's animal is there—the only animal in all creation that can make a noise like that! Look through the telescope—see those dots wheeling about there above the flashing lights? The only animal that can make that racket is man! There are men over there—and they aren't in a playful mood! Turn on the invisibility while we can, Morey—and let's get nearer!”

“Look out—here we go!” Morey began to close a tiny switch set in one side of the instrument panel—then, before the relay below could move, he had flipped it back.

“Here, you take it, Arcot—you always think about two steps ahead of me—you're quicker and know the machine better anyway.”

Quickly the two men exchanged places.

“I don't know about that, Morey,” said a voice from vacancy, for Arcot had at once thrown the ship into invisibility. “The longer we're here, the more mistakes I see we made in our calculations. I see what put me off so badly on my estimate of the intelligence of life found here! The sun gives it a double dose of heat—but also a double dose of other radiations—some of which evidently speed up evolution. Anyway, we may be able to find friends here more quickly if we aid one side or the other in the very lively battle going on there. Before we go any further, what's our decision?”

“I think it is a fine idea,” said Fuller. “But which side are we to aid—and what are the sides? We haven't even seen them yet. Let's go nearer and take a good look.”

“Yes—but are we going to join either side after looking?”

“Oh, that's unanimous!” said Wade, excitedly.

The invisible ship darted forward. They sped past the barrier of low hills, and were again high above a broad plain. With a startled gasp, Arcot cut their speed. There, floating high in the air, above a magnificent city, was a machine such as no man had ever before seen! It was a titanic airplane—monstrous, gargantuan, and every other word that denoted immensity. Fully three-quarters of a mile the huge metal wings stretched out in the dull light of the cloudy Venerian day; a machine that seemed to dwarf even the vast city beneath it. The roar of its mighty propellers was a rumbling thunder to the men in the Solarite. From it came the flashing bursts of flame.

On closer inspection, the watchers saw what seemed to be a swarm of tiny gnats flying about the mighty plane. They appeared to be attacking the giant as vainly as gnats might attack an eagle, for they could not damage the giant machine. The flashing bombs burst in blasts of yellow flame as harmlessly as so many firecrackers.

All that mighty plane was covered with heavy metal plates, fully ten inches thick, and of metal so tough that when the powerful bombs hit it they made no impression, though they blasted tremendous craters in the soil below. From it poured a steady stream of bombs that burst with a great flash of heat and light, and in an instant the tiny planes they struck streaked down as incandescent masses of metal.

Yet the giant seemed unable to approach the city—or was it defending it? No, for it was from the city that the vainly courageous little ships poured out. But certainly it was not these ships that kept the titanic battleship of the air at bay!

Tensely the men watched the uneven conflict. The rain of bombs continued, though all fell short of the city. But slowly around the metropolis there appeared an area of flaring, molten lava, and steadily this moved toward the beautiful buildings. Suddenly the battleship turned toward the city and made a short dash inward on its circling path. As though awaiting this maneuver, a battery of hissing, flaming swords of white light flashed upward, a few hundred feet from the ring of molten rock. As the titanic plane rolled, side-slipped out of the way, they passed, harmlessly, barely missing a monstrous wing.

“Which?” Arcot demanded. “I say the city. No one should destroy anything so magnificent.”

Not a dissenting voice was raised, so Arcot sent the Solarite nearer.

“But what in the world can we do to that huge thing?” Fuller's voice came eerily out of the emptiness. “It has perfect invulnerability through size alone.”

There was sudden silence among the Terrestrials as one of the tiny planes darted forward and dove at full speed directly toward one of the giant's propellers. There were fifty of these strung along each great wing. If enough of them could be destroyed, the plane must crash. There came a terrific crash—a flare of light—and splintered fragments of flaming wreckage plummeted down. Yet the mighty blades continued whirling as smoothly as ever!

What could the Solarite do against the giant monoplane? Evidently Arcot had a plan. Under his touch their machine darted high into the sky above the great plane. There was a full mile between them when he released the sustaining force of the Solarite and let it drop, straight toward the source of the battle—falling freely, ever more and more rapidly. They were rushing at the mighty plane below at a pace that made their hearts seem to pause—then suddenly Arcot cried out, “Hold on—here we stop!”

They seemed a scant hundred feet from the broad metal wings of the unsuspecting plane, when suddenly there was a tremendous jerk, and each man felt himself pressed to the floor beneath a terrific weight that made their backs crack with the load. Doggedly they fought to retain their senses; the blackness receded.

Below them they saw only a mighty sea of roaring red flames—a hell of blazing gas that roared like a score of bombs set off at once. The Solarite was sitting down on her rocket jets! All six of the rocket tubes in the base of the ship had been opened wide, and streaming from them in a furious blast of incandescent gas, the atomic hydrogen shot out in a mighty column of gas at 3500 degrees centigrade. Where the gas touched it, the great plane flared to incandescence; and in an immeasurable interval the fall of the Solarite ended, and it rebounded high into the air. Arcot, struggling against the weight of six gravities, pulled shut the little control that had sent those mighty torches blasting out. An instant later they sped away lest the plane shoot toward the gas columns.

From a safe distance they looked back at their work. No longer was the mighty plane unscathed, invulnerable, for now in its top gaped six great craters of incandescent metal that almost touched and coalesced. The great plane itself reeled, staggering, plunging downward; but long before it reached the hard soil below, it was brought into level flight, and despite many dead engines, it circled and fled toward the south. The horde of small planes followed, dropping a rain of bombs into the glowing pits in the ship, releasing their fury in its interior. In moments the beings manning the marauder had to a large extent recovered from the shock of the attack and were fighting back. In a moment—just before the ship passed over the horizon and out of sight—the Terrestrians saw the great props that had been idle, suddenly leap into motion, and in an instant the giant had left its attackers behind—fleeing from its invisible foe.

Under Arcot's guidance the ship from Earth, still invisible, returned to the approximate spot where they had destroyed the invulnerability of the Giant. Then suddenly, out of nothing, the Solarite appeared. In an instant a dozen of the tiny two-man planes darted toward it. Just that they might recognize it, Arcot shot it up a bit higher with the aid of the keel rockets at one-third power. The typical reddish flame of atomic hydrogen, he knew, would be instantaneously recognizable.

Little these planes were, but shaped like darts, and swifter than any plane of Earth. They shot along at 1000 miles an hour readily, as Arcot soon found out. It was not a minute before they had formed a long line that circled the Solarite at minimum speed, then started off in the direction of the city. On impulse Arcot followed after them, and instantly the planes increased their velocity, swiftly reaching 1000 miles per hour.

The city they were approaching was an inspiring sight. Mighty towers swept graceful lines a half mile in the air, their brightly colored walls gleaming in rainbow hues, giving the entire city the aspect of a gigantic jewel—a single architectural unit. Here was symmetry and order, with every unit in the city built around the gigantic central edifice that rose, a tremendous tower of black and gold, a full half mile in the air.

The outer parts of the city were evidently the residential districts, the low buildings and the wide streets with the little green lawns showing the care of the individual owner. Then came the apartment houses and the small stores; these rose in gentle slopes, higher and higher, merging at last with the mighty central pinnacle of beauty. The city was designed as a whole, not in a multitude of individually beautiful, but inharmonious units, like some wild mixture of melodies, each in itself beautiful, but mutually discordant.

---

V

The Terrestrians followed their escort high above these great buildings, heading toward the great central tower. In a moment they were above it, and in perfect order the ships of the Venerians shot down to land smoothly, but at high speed. On the roof of the building they slowed with startling rapidity, held back by electromagnets under the top dressing of the roof landing, as Arcot learned later.

“We can't land on that—this thing weighs too much—we'd probably sink right through it! The street looks wide enough for us to land there.” Arcot maneuvered the Solarite over the edge of the roof, and dropped it swiftly down the half mile to the ground below. Just above the street, he leveled off, and descended slowly, giving the hurrying crowds plenty of time to get from beneath it.

Landing finally, he looked curiously at the mass of Venerians who had gathered in the busy street, coming out of buildings where they evidently had sought shelter during the raid. The crowd grew rapidly as the Terrestrians watched them—people of a new world.

“Why,” exclaimed Fuller in startled surprise, “they look almost like us!”

“Why not?” laughed Arcot. “Is there any particular reason why they shouldn't look like us? Venus and Earth are very nearly the same size, and are planets of the same parent sun. Physical conditions here appear to be very similar to conditions back home, and if there's anything to Svend Arrehenius' theory of life spores being sent from world to world by sunlight, there's no reason why humanoid races cannot be found throughout the universe. On worlds, that is, suitable for the development of such life forms.”

“Look at the size of 'em,” Fuller commented.

Their size was certainly worth noting, for in all that crowd only the obviously young were less than six feet tall. The average seemed to be seven feet—well-built men and women with unusually large chests, who would have seemed very human indeed, but for a ghastly, death-like blue tinge to their skin. Even their lips were as bright a blue as man's lips are red. The teeth seemed to be as white as any human's, but their mouths were blue.

“They look as if they'd all been eating blueberries!” laughed Wade. “I wonder what makes their blood blue? I've heard of blue-blooded families, but these are the first I've ever seen!”

“I think I can answer that,” said Morey slowly. “It seems odd to us—but those people evidently have their blood based on hemocyanin. In us, the oxygen is carried to the tissues, and the carbon dioxide carried away by an iron compound, hemoglobin, but in many animals of Earth, the same function is performed by a copper compound, hemocyanin, which is an intense blue. I am sure that that is the explanation for these strange people. By the way, did you notice their hands?”

“Yes, I had. They strike me as having one too many fingers—look there—that fellow is pointing—why—his hand hasn't too many fingers, but too many thumbs! He has one on each side of his palm! Say, that would be handy in placing nuts and bolts, and such fine work, wouldn't it?”

Suddenly a lane opened in the crowd, and from the great black and gold building there came a file of men in tight-fitting green uniforms; a file of seven-foot giants. Obviously they were soldiers of some particular branch, for in the crowd there were a number of men dressed in similar uniforms of deep blue.

“I think they want one or more of us to accompany them,” Arcot said. “Let's flip a coin to decide who goes—two better stay here, and two go. If we don't come back inside of a reasonable period of time, one of you might start making inquiries; the other can send a message to Earth, and get out of harm's way till help can come. I imagine these people are friendly now, however—else I wouldn't go.”

The leader of the troop stepped up to the door of the Solarite, and coming to what was obviously a position of attention, put his left hand over his right breast in an equally obvious salute, and waited.

The coin was flipped with due ceremony—it would decide which of them were to have the distinction of being the first Terrestrians to set foot on Venus. Arcot and Morey won, and they quickly put on the loose-fitting ventilated cooling suits that they might live comfortably in the hot air outside—for the thermometer registered 150°!

The two men quickly walked over to the airlock, entered, closed it behind them, and opened the outer door. There was a slight rush of air, as the pressure outside was a bit lower than that inside. There was a singing in their ears, and they had to swallow several times to equalize the pressure.

The guards at once fell into a double row on either side of them, and the young officer strode ahead. He himself had curbed his curiosity after the single startled glance he had given these strange men. Only their hands were visible, for the cooling suits covered them almost completely, but the strange pink color must indeed have been startling to the eyes; also their dwarf stature, and the strange suits they wore. The men of his little troop, however, as well as the people in the crowd about them, were not so disinterested. They were looking in eager amazement at these men who had just saved their city, these strange small men with their queer pink skin. And most surprising of all, perhaps, the inner thumb was missing from each hand!

But soon they had passed beyond the sight of the crowd, which was held in check by a handful of the deep blue uniformed men.

“Those fellows would never hold such a Terrestrial crowd back if visitors from another planet landed!” remarked Morey wonderingly.

“How do they know we are visitors from another planet?” Arcot objected. “We suddenly appeared out of nowhere—they don't even know our direction of approach. We might be some strange race of Venerians as far as they know.”

They walked briskly up to the massive gold and black entrance, and passed through the great doors that seemed made of solid copper, painted with some clear coating that kept the metal lustrous, the rich color shining magnificently. They stood open wide now, as indeed they always were. Even the giant Venerians were dwarfed by these mighty doors as they passed through into an equally vast hall, a tremendous room that must have filled all the front half of the ground floor of the gigantic building, a hall of graceful columns that hid the great supporting members. The stone, they knew, must serve the Venerians as marble serves us, but it was a far more handsome stone. It was a rich green, like the green of thick, heavy grass in summer when the rain is plentiful. The color was very pleasing to the eye, and restful too. There was a checker-board floor of this green stone, alternated with another, a stone of intense blue. They were hard, and the colors made a very striking pattern, pleasingly different from what they had been accustomed to, but common to Venus, as they later learned.

At last the party had crossed the great hall, and stopped beside a large doorway. The officer halted for a moment, and gestured toward two of his men, who remained, while the others walked quickly away. The diminished party stepped through the doorway into a small room whose walls were lined with copper, and an instant later, as the officer pushed a small button, there was a low hiss of escaping air, and a copper grating sprang quickly up across the opening of the elevator. He touched another button, and there was the familiar sinking feeling as the car rose, a low hum seeming to come from its base.

The elevator rose swiftly through a very considerable distance—up—up, endlessly.

“They must have some wonderfully strong cables here on Venus!” Morey exclaimed. “The engineers of Terrestrial buildings have been wondering for some time how to get around the difficulty of shifting elevators. The idea of changing cars doesn't appeal to me, either—but we must have risen a long way!”

“I should say so—I wonder how they do it. We've been rising for a minute and a half at a very fair clip—there we are; end of the line—I want to look at this car!” Arcot stepped over to the control board, looked at it closely, then stepped out and peered down between the car and the shaft as the copper grating fell, simultaneously pulling down with it the door that had blocked off the hallway.

“Come here, Morey—simple system at that! It would be so, of course. Look—they have tracks, and a regular trolley system, with cog rails alongside, and the car just winds itself up! They have a motor underneath, I'll bet, and just run it up in that way. They have never done that on Earth because of the cost of running the car up without too much power. I think I see the solution—the car has electro-dynamical brakes, and descending, just slows itself down by pumping power into the line to haul some other car up. This is a mighty clever scheme!”

As Arcot straightened, the officer beckoned to him to follow, and started down the long corridor which was lined on either side with large doorways, much like a very exotic earthly office building. Passing through a long series of branching corridors they at last reached one that terminated in a large office, into which the young officer led them. Snapping to attention, he spoke briefly and rapidly, saluted and retired with his two men.

The man before whom the Terrestrians stood was a tall, kindly-faced old gentleman. His straight black hair was tinged with bluish gray, and the kindly face bore the lines of age, but the smiling eyes, and the air of sincere interest gave his countenance an amazingly youthful air. It was warm and friendly despite its disconcerting blueness. He looked curiously, questioningly at the two men before him, looked at their hands, his eyes widening in surprise; then he stepped quickly forward, and extended his hand, at the same time looking toward Arcot.

Smiling, Arcot extended his own. The Venerian grasped it—then with an exclamation on the part of each, they mutually released each other, Arcot feeling an uncomfortable sensation of heat, just as the Venerian felt a flash of intense cold! Each stared from his hand to the hand of the other in surprise, then a smile curved the blue lips of the Venerian as he very emphatically put his hand at his side. Arcot smiled in turn, and said to Morey in an animated tone:

“They have a body temperature of at least 170° Fahrenheit. It would naturally be above room temperature, which is 150° here, so that they are most unpleasantly hot to us. Marvelous how nature adapts herself to her surroundings!” He chuckled. “I hope these fellows don't have fevers. They'd be apt to boil over!”

The Venerian had picked up a small rectangle of black material, smooth and solid. He drew quickly upon it with what appeared to be a pencil of copper. In a moment he handed the tablet to Arcot, who reached out for it, then changed his mind, and motioned that he didn't want to burn his fingers. The old Venerian held it where Arcot could see it.

“Why, Morey, look here—I didn't think they had developed astronomy to any degree, because of the constant clouds, but look at this. He has a nice little map of the solar system, with Mercury, Venus, Earth, the Moon, Mars, and all the rest on it. He has drawn in several of the satellites of Jupiter and of Saturn too.”

The Venerian pointed to Mars and looked inquisitively at them. Arcot shook his head and pointed quickly to Earth. The Venetian seemed a bit surprised at this, then thought a moment and nodded in satisfaction. He looked at Arcot intently. Then to the latter's amazement, there seemed to form in his mind a thought—at first vague, then quickly taking definite form.

“Man of Earth,” it seemed to say, “we thank you—you have saved our nation. We want to thank you for your quick response to our signals. We had not thought that you could answer us so soon.” The Venerian seemed to relax as the message was finished. It obviously had required great mental effort.

Arcot looked steadily into his eyes now, and tried to concentrate on a message—on a series of ideas. To him, trained though he was in deep concentration on one idea, the process of visualizing a series of ideas was new, and very difficult. But he soon saw that he was making some progress.

“We came in response to no signals—exploration only—we saw the battle—and aided because your city seemed doomed, and because it seemed too beautiful to be destroyed.”

“What's it all about, Arcot?” asked Morey wonderingly, as he watched them staring at each other.

“Mental telepathy,” Arcot answered briefly. “I'm terribly thick from his point of view, but I just learned that they sent signals to Earth—why, I haven't learned—but I'm making progress. If I don't crack under the strain, I'll find out sooner or later—so wait and see.” He turned again to the Venerian.

The latter was frowning at him rather dubiously. With sudden decision he turned to his desk, and pulled down a small lever. Then again he looked intently at Arcot.

“Come with me—the strain of this conversation is too great—I see you do not have thought transference on your world.”

“Come along, Morey—we're going somewhere. He says this thought transference is too much for us. I wonder what he is going to do?”

Out into the maze of halls they went again, now led by the kindly seven-foot Venerian. After walking through a long series of halls, they reached a large auditorium, where already there had gathered in the semi-circle of seats a hundred or so of the tall, blue-tinged Venerians. Before them, on a low platform, were two large, deeply-cushioned chairs. To these chairs the two Terrestrians were led.

“We will try to teach you our language telepathically. We can give you the ideas—you must learn the pronunciation, but this will be very much quicker. Seat yourselves in these chairs and relax.”

The chairs had been designed for the seven-footers. These men were six feet and six feet six, respectively, yet it seemed to them, as they sank into the cushions, that never had they felt such comfortable chairs. They were designed to put every muscle and every nerve at rest. Luxuriously, almost in spite of themselves, they relaxed.

Dimly Arcot felt a wave of sleepiness sweep over him; he yawned prodigiously. There was no conscious awareness of his sinking into a deep slumber. It seemed that suddenly visions began to fill his mind—visions that developed with a returning consciousness—up from the dark, into a dream world. He saw a mighty fleet whose individual planes were a mile long, with three-quarters of a mile wingspread—titanic monoplanes, whose droning thunder seemed to roar through all space. Then suddenly they were above him, and from each there spurted a great stream of dazzling brilliance, an intense glow that reached down, and touched the city. An awful concussion blasted his ears. All the world about him erupted in unimaginable brilliance; then darkness fell.

Another vision filled his mind—a vision of the same fleet hanging over a giant crater of molten rock, a crater that gaped angrily in a plain beside low green hills—a crater that had been a city. The giants of the air circled, turned, and sped over the horizon. Again he was with them—and again he saw a great city fuse in a blazing flash of blinding light—again and yet again—until around all that world he saw smoking ruins of great cities, now blasted crimson craters in a world of fearful desolation.

The destroyers rode up, up, up—out of the clouds—and he was with them. Out beyond the swirling mists, where the cold of space seemed to reach in at them, and the roaring of the mighty propellers was a thin whine—then suddenly that was gone, and from the tail of each of the titanic machines there burst a great stream of light, a blazing column that roared back, and lit all space for miles around—rocket jets that sent them swiftly across space!

He saw them approaching another world, a world that shone a dull red, but he saw the markings and knew that it was Earth, not Mars. The great planes began falling now—falling at an awful speed into the upper air of the planet, and in an instant the rocket flares were gone, fading and dying in the dense air. Again there came the roar of the mighty propellers. Then swiftly the fleet of giants swooped down, lower and lower. He became aware of its destination—a spot he knew must be New York—but a strangely distorted New York—a Venerian city, where New York should have been. And again, the bombs rained down. In an instant the gigantic city was a smoking ruin.

The visions faded, and slowly he opened his eyes, looked about him. He was still in the room of the circle of chairs—he was still on Venus—then with sudden shock, understanding came. He knew the meaning of these visions—the meaning of that strangely distorted New York, of that red Earth. It meant that this was what the Venerians believed was to happen! They were trying to show him the plans of the owners and builders of those gigantic ships! The New York he had seen was New York as these men imagined it.

Startled, confused, his forehead furrowed, he rose unsteadily to his feet. His head seemed whirling in the throes of a terrific headache. The men about him were looking anxiously at him. He glanced toward Morey. He was sleeping deeply in the seat, his features now and again reflecting his sensations. It was his turn to learn this new language and see the visions.

The old Venerian who had brought them there walked up to Arcot and spoke to him in a softly musical language, a language that was sibilant and predominated in liquid sounds; there were no gutturals, no nasals; it was a more musical language than Earth men had ever before heard, and now Arcot started in surprise, for he understood it perfectly; the language was as familiar as English.

“We have taught you our language as quickly as possible—you may have a headache, but you must know what we know as soon as possible. It may well be that the fate of two worlds hangs on your actions. These men have concentrated on you and taught you very rapidly with the massed power of their minds, giving you visions of what we know to be in preparation. You must get back to your wonderful ship as quickly as possible; and yet you must know what has happened here on our world in the last few years, as well as what happened twenty centuries ago.

“Come with me to my office, and we will talk. When your friend has also learned, you may tell him.”

Quickly Arcot followed the Venerian down the long corridors of the building. The few people they met seemed intent on their own business, paying little attention to them.

At last they seated themselves in the office where Arcot had first met his escort; and there he listened to a new history—the history of another planet.

“My name is Tonlos,” the old man said. “I am a leader of my people—though my title and position are unimportant. To explain would entail a prolonged discussion of our social structure, and there is no time for that. Later, perhaps—but now to our history.

“Twenty centuries ago,” Tonlos continued, “there were two great rival nations on this planet. The planet Turo is naturally divided so that there would be a tendency toward such division. There are two enormous belts of land around the globe, one running from about 20 degrees north of the equator to about 80 degrees north. This is my country, Lanor. To the south there is a similar great belt of land, of almost identical size, Kaxor. These two nations have existed for many thousands of our years.

“Two thousand years ago a great crisis arose in the affairs of the world—a great war was in process of starting—but a Lanorian developed a weapon that made it impossible for the Kaxorians to win—and war was averted. The feeling was so strong, however, that laws were passed which stopped all intercourse between the two nations for these thousands of years. By devious ways we've learned that Kaxor has concentrated on the study of physics, perhaps in hopes of finding a weapon with which they could threaten us once more. Lanor has studied the secrets of the human mind and body. We have no disease here any longer; we have no insanity. We are students of chemistry, but physics has been neglected to a great extent. Recently, however, we have again taken up this science, since it alone of the main sciences had not received our study. Only twenty-five years have been spent on these researches, and in that short time we cannot hope to do what the Kaxorians have done in two thousand.

“The secret of the heat ray, the weapon that prevented the last war, had been almost forgotten. It required diligent research to bring it to life again, for it is a very inefficient machine—or was. Of late, however, we have been able to improve it, and now it is used in commerce to smelt our ores. It was this alone that allowed this city to put up the slight resistance that we did. We were surely doomed. This is the capital of Lanor, Sonor. We—and the nation—would have fallen but for you.

“We have had some warning that this was coming. We have spies in Kaxor now, for we learned of their intentions when they flew the first of their giant planes over one of our cities and dropped a bomb! We have been trying, since we discovered the awful scope of their plans, to send you a warning if you could not help us. That you should come here at this particular time is almost beyond belief—a practically impossible coincidence—but perhaps there is more than coincidence behind it? Who knows?” He paused briefly; went on with a heavy sigh: “Since you drove that plane away, we can expect a new raid at any moment, and we must be prepared. Is there any way you can signal your planet?”

“Yes—we can signal easily,” Arcot answered; he struggled with the newly acquired language. “I do not know the word in your tongue—it may be that you do not have it—radio we call it—it is akin to light, but of vastly longer wavelength. Produced electrically, it can be directed like light and sent in a beam by means of a reflection. It can penetrate all substances except metals, and can leak around them, if it be not directional. With it I can talk readily with the men of Earth, and this very night I will.”

Arcot paused, frowning thoughtfully, then continued, “I know there's definite need for haste, but we can't do anything until Morey has received the knowledge you've given me. While we're waiting here, I might just as well learn all I can about your planet. The more I know, the more intelligently I'll be able to plan for our defense.”

In the conversation which followed, Arcot gained a general knowledge of the physical makeup of Venus. He learned that iron was an exceedingly rare element on the planet, while platinum was relatively plentiful. Gold, though readily available, was considered a nuisance, since it was of no practical value due to its softness, excessive weight and its affinity for many catalysts. Most of the other metallic elements were present in quantities approximating those of Earth, except for an element called “morlus”. When Tonlos mentioned this, Arcot said:

“Morlus—I have the word in your language—but I do not know the element. What is it?”

“Why—here is some!”

Tonlos handed Arcot a small block of metal that had been used as a weight on a table in one corner of the room. It seemed fairly dense, about as heavy as iron, but it had a remarkably bluish tint. Obviously, it was the element that composed the wings of the airplane they had seen that afternoon. Arcot examined it carefully, handicapped somewhat by its heat. He picked up a small copper rod and tried to scratch it but there was no noticeable effect.

“You cannot scratch it with copper,” said Tonlos. “It is the second hardest metal we know—it is not as hard as chromium, but far less brittle. It is malleable, ductile, very very strong, very tough, especially when alloyed with iron, but those alloys are used only in very particular work because of iron's rarity.”

Indicating the bluish block, Arcot said, “I'd like to identify this element. May I take it back to the ship and test it?”

“You may, by all means. You will have considerable difficulty getting it into solution, however. It is attacked only by boiling selenic acid which, as you must know, dissolves platinum readily. The usual test for the element is to so dissolve it, oxidize it to an acid, then test with radium selenate, when a brilliant greenish blue salt is—”

“Test with radium selenate!” Arcot exclaimed. “Why, we have no radium salts whatever on Earth that we could use for that purpose. Radium is exceedingly rare!”

“Radium is by no means plentiful here,” Tonlos replied, “but we seldom have to test for morlus, and we have plenty of radium salts for that purpose. We have never found any other use for radium—it is so active that it combines with water just as sodium does; it is very soft—a useless metal, and dangerous to handle. Our chemists have never been able to understand it—it is always in some kind of reaction no matter what they do, and still it gives off that very light gas, helium, and a heavy gas, niton, and an unaccountable amount of heat.”

“Your world is vastly different from ours,” Arcot commented. He told Tonlos of the different metals of Earth, the non-metals, and their occurrence. But try as he would, he could not place the metal Tonlos had given him.

Morey's arrival interrupted their discussion. He looked very tired, and very serious. His head ached from his unwonted mental strain, just as Arcot's had. Briefly Arcot told him what he had learned, concluding with a question as to why Morey thought the two planets, both members of the same solar family, should be so different.

“I have an idea,” said Morey slowly, “and it doesn't seem too wacky. As you know, by means of solar photography, astronomers have mapped the sun, charting the location of the different elements. We've seen hydrogen, oxygen, silicon and others, and as the sun aged, the elements must have been mixed up more and more thoroughly. Yet we have seen the vast areas of single elements. Some of those areas are so vast that they could easily be the source of an entire world! I wonder if it is not possible that Earth was thrown off from some deposit rich in iron, aluminum and calcium, and poor in gold, radium and those other metals—and particularly poor in one element. We have located in the sun the spectrum of an element we have named coronium—and I think you have a specimen of coronium in your hand there! I'd say Venus came from a coronium-rich region!”

The discussion ended there, for already the light outside had deepened to a murky twilight. The Terrestrians were led quickly down to the elevator, which dropped them rapidly to the ground. There was still a large crowd about the Solarite, but the way was quickly cleared for them. As the men passed through the crowd, a peculiar sensation struck them very forcibly. It seemed that everyone in the crowd was wishing them the greatest success—the best of good things in every wish.

“The ultimate in applause! Morey, I'll swear we just received a silent cheer!” exclaimed Arcot, as they stood inside the airlock of the ship once more. It seemed home to them now! In a moment they had taken off the uncomfortable ventilating suits and stepped once more into the room where Wade and Fuller awaited them.

“Say—what were you fellows doing?” Wade demanded. “We were actually getting ready to do some inquiring about your health!”

“I know we were gone a long time—but when you hear the reason you'll agree it was worth it. See if you can raise Earth on the radio, Morey, will you, while I tell these fellows what happened? If you succeed, tell them to call in Dad and your father, and to have a couple of tape recorders on the job. We'll want a record of what I have to send. Say that we'll call back in an hour.” Then, while Morey was busy down in the power room sending the signals out across the forty million miles of space that separated them from their home planet, Arcot told Wade and Fuller what they had learned.

Morey finally succeeded in getting his message through, and returned to say that they would be waiting in one hour. He had had to wait eight minutes after sending his message to get any answer, however, due to time required for radio waves to make the two-way trip.

“Fuller,” Arcot said, “as chef, suppose you see what you can concoct while Wade and I start on this piece of coronium and see what there is to learn.”

At the supper table Wade and Arcot reported to the others the curious constants they had discovered for coronium. It was not attacked by any acid except boiling selenic acid, since it formed a tremendous number of insoluble salts. Even the nitrate violated the long-held rule that “all nitrates are soluble”—it wouldn't dissolve. Yet it was chemically more active than gold.

But its physical constants were the most surprising. It melted at 2800° centigrade, a very high melting point indeed. Very few metals are solid at that temperature. But the tensile strength test made with a standard bar they finally turned out by means of a carbaloy tool, gave a reading of more than one million, three hundred thousand pounds per square inch! It was far stronger than iron—stronger than tungsten, the strongest metal heretofore known. It was twice as strong as the Earth's strongest metal!

Fuller whistled in awe. “No wonder they can make a plane like that when they have such a metal to work with.” The designing engineer had visions of a machine after his own heart—one in which half the weight was not employed in holding it together!

It was a little later that they got communication through to Earth, and the men went to the power room. The television screen was struggling to form a clear image despite the handicap of forty million miles of space. In a moment it had cleared, though, and they saw the face of Dr. Arcot. He showed plainly that he was worried about the startling news that had reached him already, sketchy though it was. After brief though warm greetings, his son rapidly outlined to him the full extent of their discoveries, and the force that Earth would have to meet.

“Dad, these Kaxorians have planes capable of far more than a thousand miles an hour in the air. For some reason the apparatus they use to propel them in space is inoperative in air, but their propellers will drive them forward faster than any plane Earth ever saw. You must start at once on a fleet of these molecular motion planes—and a lot of the gas Wade developed—you know how to make it—the animation suspending gas. They don't have it—and I believe it will be useful. I'll try to develop some new weapons here. If either of us makes any progress along new lines—we'll report to the other. I must stop now—a Lanorian delegation is coming.” After a few words of farewell, Arcot severed connections with the Earth and arose to await the arrival of the visitors.

Since the return of the Terrestrians to the Solarite, a great crowd of Venerians had gathered around it, awaiting a glimpse of the men, for the news had spread that this ship had come from Earth. Now, the crowd had divided, and a group of men was approaching, clothed in great heavy coats that seemed warm enough to wear in Terrestrial arctic regions!

“Why—Arcot—what's the idea of the winter regalia?” asked Fuller in surprise.

“Think a moment—they are going to visit a place whose temperature is seventy degrees colder than their room temperature. In the bargain, Venus never has any seasonal change of temperature, and a heavy bank of clouds that eternally cover the planet keeps the temperature as constant as a thermocouple arrangement could. The slight change from day to night is only appreciable by the nightly rains—see—the crowd is beginning to break up now. It's night already, and there is a heavy dew settling. Soon it will be rain, and the great amount of moisture in the air will supply enough heat, in condensing, to prevent a temperature drop of more than two or three degrees. These men are not used to changes in temperature as we are and hence they must protect themselves far more fully.”

Three figures now entered the airlock of the Solarite, and muffled in heavy garments as they were, large under any conditions, they had to come through one at a time.

Much that Arcot showed them was totally new to them. Much he could not explain to them at all, for their physics had not yet reached that stage.

But there was one thing he could show them, and he did. There were no samples of the liquids he wanted, but their chemistry was developed to a point that permitted the communication of the necessary data and Arcot told them the formula of Wade's gas. Its ability to penetrate any material at ordinary temperatures, combined with its anesthetic properties, gave it obvious advantages as a weapon for rendering the opposing forces defenseless.

Since it was able to penetrate all substances, there was no means of storing it. Hence it was made in the form of two liquids which reacted spontaneously and produced the gas, which was then projected to the spot where needed.

Arcot asked now that the Venerian chemists make him a supply of these two liquids; and they promptly agreed. He felt he would have a fighting chance in combatting the enemy if he could but capture one of their flying forts. It seemed a strange task! Capturing so huge a machine with only the tiny Solarite—but Arcot felt there was a good possibility of his doing it if he but had a supply of that gas.

There was one difficulty—one step in the synthesis required a considerable quantity of chlorine. Since chlorine was rare on Venus, the men were forced to sacrifice most of their salt supply; but this chlorine so generated could be used over and over again.

It was quite late when the Venerians left, to go again into the scalding hot rain, rain that seemed to them to be a cold drizzle. After they had gone, the Terrestrians turned in for the night, leaving a telephone connection with the armed guard outside.

---

The dull light of the Venerian day was filtering in through the windows the next morning when the Terrestrians awoke. It was eight o'clock, New York time, but Sonor was working on a twenty-three hour day. It happened that Sonor and New York had been in opposition at midnight two nights ago, which meant that it was now ten o'clock Sonorian time. The result was that Arcot left the car to speak to the officer in charge of the guard about the ship.

“We need some pure water—water free of copper salts. I think it would be best if you can get me some water that has been distilled. That is, for drinking. Also we need about two tons of water of any kind—the ship's tanks need recharging. I'd like about a ton of the drinking water.” Arcot had to translate the Terrestrian measures into the corresponding Venerian terms, of course, but still the officer seemed puzzled. Such a large amount of water would create a real problem in transportation. After apparently conferring by telepathic means with his superiors, the officer asked if the Solarite could be moved to some more accessible place.

Arcot agreed to have it moved to a spot just outside the city, where the water could be procured directly from a stream. The drinking water would be ready when he returned to the city.

The Solarite was moved to the bank of the little river and the electrolysis apparatus was set up beside it. During the previous day, and ever since they had landed on Venus, all their power had been coming from the storage cells, but now that the electrolysis apparatus was to establish such a heavy and constant drain, Arcot started the generator, to both charge the cells, and to do the work needed.

Throughout the day there could be heard the steady hum of the generator, and the throb-throb-throb of the oxygen pump, as the gas was pumped into the huge tanks. The apparatus they were using produced the gas very rapidly, but it was near nightfall before the huge tanks had again been filled. Even then there was a bit more room for the atomic hydrogen that was simultaneously formed, although twice as much hydrogen as oxygen was produced. Its task completed, the Solarite rose again and sped toward the distant city.

A soft red glow filled the sky now, for even through the miles of clouds the intense sun was able to force some direct rays, and all the city was lighted with that warm radiance. The floodlights had not yet been turned on, but the great buildings looming high in the ruddy light were wonderfully impressive, the effect being heightened by the planned construction, for there were no individual spires, only a single mass that grew from the ground to tower high in the air, like some man-made mountain.

Back at the Capital the Solarite again settled into the broad avenue that had been cut off to traffic now, and allotted to it as its resting place. Tonlos met them shortly after they had settled into place, and with him were five men, each carrying two large bottles.

“Ah-co,” as Tonlos pronounced the Terrestrian name, “we have not been able to make very much of the materials needed for your gas, but before we made any very great amount, we tried it out on an animal, whose blood structure is the same as ours, and found it had the same effect, but that in our case the iodide of potassium is not as effective in awakening the victim as is the sorlus. I do not know whether you have tried that on Terrestrial animals or not. Luckily sorlus is the most plentiful of the halogen groups; we have far more of it than of chlorine, bromine or iodine.”

“Sorlus? I do not know of it—it must be one of the other elements that we do not have on Earth. What are its properties?”

“It, too, is much like iodine, but heavier. It is a black solid melting at 570 degrees; it is a metallic looking element, will conduct electricity somewhat, oxidizes in air to form an acidic oxide, and forms strong oxygen acids. It is far less active than iodine, except toward oxygen. It is very slightly soluble in water. It does not react readily with hydrogen, and the acid where formed is not as strong as HI.”

“I have seen so many new things here, I wonder if it may not be the element that precedes niton. Is it heavier than that?”

“No,” replied Tonlos; “it is just lighter than that element you call niton. I think you have none of it.”

“Then,” said Arcot, “it must be the next member of the halogen series, Morey. I'll bet they have a number of those heavier elements.”

The gas was loaded aboard the Solarite that evening, and when Wade saw the quantity that they had said was “rather disappointingly small” he laughed heartily.

“Small! They don't know what that gas will do! There's enough stuff there to gas this whole city. Why, with that, we can bring down any ship! But tell them to go on making it, for we can use it on the other ships.”

Again that night they spoke with Earth, and Morey, Senior, told them that work was already under way on a hundred small ships. They were using all their own ships already, while the Government got ready to act on the idea of danger. It had been difficult to convince them that someone on Venus was getting ready to send a force to Earth to destroy them; but the weight of their scientific reputation had turned the trick. The ships now under construction would be ready in three weeks. They would be unable to go into space, but they would be very fast, and capable of carrying large tanks of the gas-producing chemicals.

It was near midnight, Venerian time, when they turned in. The following day they planned to start for the Kaxorian construction camp. They had learned from Tonlos that there were but five of the giant planes completed now, but there were fifteen more under construction, to make up the fleet of twenty that was to attack Earth. These fifteen others would be ready in a week—or less. When they were ready, the Solarite would stand small chance. They must capture one of the giants and learn its secrets, and then, if possible, with the weapons and knowledge of two worlds, defeat them. A large order!

Their opportunity came sooner than they had hoped for—or wanted. It was about three o'clock in the morning when the telephone warning hummed loudly through the ship. Arcot answered.

Far to the east and south of them the line of scout planes that patrolled all the borders of Lanor had been broken. Instantaneously, it seemed, out of the dark, its lights obscured, the mighty Kaxorian craft had come, striking a tiny scout plane head on, destroying it utterly before the scout had a chance to turn from the path of the titanic ship. But even as the plane spun downward, the pilot had managed to release a magnesium flare, a blindingly brilliant light that floated down on a parachute, and in the blaze of the white light it gave off, the other scouts at a few miles distance had seen the mighty bulk of the Kaxorian plane. At once they had dropped to the ground and then, by telephone lines, had sent their report to far off Sonor.

In moments the interior of the Solarite became a scene of swift purposeful activity. All day the Terrestrians had been able to do so little in preparation for the conflict they knew must come, the battle for two worlds. They had wanted action, but they had no weapons except their invisibility and the atomic hydrogen. It would not sink a plane. It would only break open its armor, and they hoped, paralyze its crew. And on this alone they must pin their hopes.

---

VI

Arcot lifted the Solarite at once high into the air, and started toward the point on the border, where the plane had been seen crossing. In a short time Wade relieved him at the controls while he dressed.

They had been flying on in silence for about an hour, when suddenly Wade made out in the distance the great bulk of the plane, against the dull gray of the clouds, a mile or so above them. It seemed some monstrous black bat flying there against the sky, but down to the sensitive microphone on the side of the Solarite came the drone of the hundred mighty propellers as the great plane forged swiftly along.

Just how rapidly these giants moved, Arcot had not appreciated until he attempted to overtake this one. It was going over a mile a second now—a speed that demanded only that it move its own length in about five-eights of a second! It made this tremendous speed by streamlining and through sheer power.

The Solarite hovered high above the dark ship at length, the roar of the terrific air blast from its propellers below coming up to them as a mighty wave of sound that made their own craft tremble! The hundred gigantic propellers roaring below, however, would distribute their gas perfectly.

“We're going invisible,” Arcot exclaimed. “Look out!” There was a click as the switch shut, and the Solarite was as transparent as the air above it. Arcot drove his ship swiftly, above and ahead of the mighty colossus, then released the gas. There was a low hiss from the power room, barely detectable despite the vacuum that shut them off from the roar of the Kaxorian plane. The microphone had long since been disconnected. Out of the gas vent streamed a cloud of purplish gas, becoming faintly visible as it left the influence of the invisibility apparatus, but only to those who knew where to look for it. The men in that mighty plane could not see it as their machine bore down into the little cloud of gas.

Tensely the Terrestrians waited. Moments—and the gigantic plane wobbled! There was a sudden swerve that ended in a nose dive, straight toward Venus seven miles below.

That the ship should crash into the ground below was not at all Arcot's plan, and he was greatly relieved when it flattened its dive and started to climb, its incalculable mass rapidly absorbing its kinetic energy. Down from its seven mile height it glided, controlling itself perfectly as Arcot released the last of the first four containers of the liquid gas makers, putting to sleep the last man on the ship below.

In a long glide that carried it over many miles, the great ship descended. It had sunk far, and gone smoothly, but now there loomed ahead of it a range of low hills! It would certainly crash into the rocky cliffs ahead! Nearer and nearer drew the barrier while Arcot and the others watched with rigid attention. It might skim above those low hills at that—just barely escaping.... The watchers cringed as head on, at nearly two thousand miles an hour, the machine crashed into the rocks. Arcot had snapped the loud speaker into the circuit once more, and now as they looked at the sudden crash below, there thundered up to them mighty waves of sound!

The giant plane had struck about twenty feet from the top of a nearly perpendicular cliff. The terrific crash was felt by seismographs in Sonor nearly two thousand miles away! The mighty armored hull plowed into the rocks like some gigantic meteor, the hundreds of thousands of tons crushing the rocky precipice, grinding it to powder, and shaking the entire hill. The cliff seemed to buckle and crack. In moments the plane had been brought to rest, but it had plowed through twenty feet of rock for nearly an eighth of a mile. For an instant it hung motionless, perched perilously in the air, its tail jutting out over the little valley, then slowly, majestically it sank, to strike with a reverberating crash that shattered the heavy armor plate!

For another instant the great motors continued turning, the roar of the propellers like some throbbing background to the rending crashes as the titanic wreck came to rest. Suddenly, with a series of roaring explosions, the bank of motors in the left wing blew up with awful force. There was a flash of indescribable brilliance that momentarily blinded the watching Terrestrians; then there came to the microphone such waves of sound as it could not reproduce. From the rock on which rested the fused mass of metal that they knew had been the wing, rose a great cloud of dust. Still the motors on the other side of the ship continued roaring and the giant propellers turned. As the blast of air blew the dust away, the Terrestrians stared in unbounded amazement. Up from the gaping, broken wing lanced a mighty beam of light of such dazzling intensity that Arcot swiftly restored them to visibility that they might shut it out. There was a terrific hissing, crackling roar. The plane seemed to wobble as it lay there, seemingly recoiling from that flaming column. Where it touched the cliff there was intense incandescence that made the rock glow white hot, then flow down in a sluggish rivulet of molten lava! For five minutes longer this terrific spectacle lasted, while Arcot withdrew the Solarite to a safer distance.

The fifty motors of the remaining wing seemed slowing down now—then suddenly there was such a crash and towering flash of light as no human being had ever seen before! Up—up into the very clouds it shot its mighty flame, a blazing column of light that seemed to reach out into space. The Solarite was hurled back end over end, tumbling, falling. Even the heavy gyroscopes could not hold it for an instant, but quickly the straining motors brought them to rest in air that whirled and whined about them. They were more than twenty miles from the scene of the explosion, but even at that distance they could see the glow of the incandescent rock. Slowly, cautiously they maneuvered the Solarite back to the spot, and looked down on a sea of seething lava!

Morey broke the awed silence. “Lord—what power that thing carries! No wonder they could support it in the air! But—how can they control such power? What titanic forces!”

Slowly Arcot sent the Solarite away into the night—into the kindly darkness once more. His voice when he spoke at last was oddly restrained.

“I wonder what those forces were—they are greater than any man has ever before seen! An entire hill fused to molten, incandescent rock, not to mention the tons and tons of metal that made up that ship.

“And such awful forces as these are to be released on our Earth!” For an interminable period they sat silent as the panorama of hills glided by at a slow two-hundred miles an hour. Abruptly Arcot exclaimed, “We must capture a ship. We'll try again—we'll either destroy or capture it—and either way we're ahead!”

---

Aimlessly they continued their leisurely course across a vast plain. There were no great mountains on Venus, for this world had known no such violent upheaval as the making of a moon. The men were lost in thought, each intent on his own ideas. At length Wade stood up, and walked slowly back to the power room.

Suddenly the men in the control room heard his call:

“Arcot—quick—the microphone—and rise a mile!”

The Solarite gave a violent lurch as it shot vertically aloft at tremendous acceleration. Arcot reached over swiftly and snapped the switch of the microphone. There burst in upon them the familiar roaring drone of a hundred huge propellers. No slightest hum of motor, only the vast whining roar of the mighty props.

“Another one! They must have been following the first by a few minutes. We'll get this one!” Arcot worked swiftly at his switches. “Wade—strap yourself in the seat where you are—don't take time to come up here.”

They followed the same plan which had worked so well before. Suddenly invisible, the Solarite flashed ahead of the great plane. The titanic wave of rushing sound engulfed them—then again came the little hiss of the gas. Now there were no hills in sight, as far as the eye could see. In the dim light that seemed always to filter through these gray clouds they could see the distant, level horizon.

Several dragging minutes passed before there was any evident effect; the men from Earth were waiting for that great ship to waver, to wobble from its course. Suddenly Arcot gave a cry of surprise. Startled amazement was written all over his face, as his companions turned in wonderment to see that he was partially visible! The Solarite, too, had become a misty ghost ship about them; they were becoming visible! Then in an instant it was gone—and they saw that the huge black bulk behind them was wavering, turning; the thunderous roar of the propellers fell to a whistling whine; the ship was losing speed! It dipped, and shot down a bit—gained speed, then step by step it glided down—down—down to the surface below. The engines were idling now, the plane running more and more slowly.

They were near the ground now—and the watchers scarcely breathed. Would this ship, too, crash? It glided to within a half mile of the plain—then it dipped once more, and Arcot breathed his relief as it made a perfect landing, the long series of rollers on the base of the gigantic hull absorbing the shock of the landing. There were small streams in the way—a tree or two, but these were obstacles unnoticed by the gargantuan machine. Its mighty propellers still idling slowly, the huge plane rolled to a standstill.

Swooping down, the Solarite landed beside it, to be lost in the vast shadows of the mighty metal walls.

Arcot had left a small radio receiver with Tonlos in Sonor before he started on this trip, and had given him directions on how to tune in on the Solarite. Now he sent a message to him, telling that the plane had been brought down, and asking that a squadron of planes be sent at once.

Wade and Arcot were elected to make the first inspection of the Kaxorian plane, and clad in their cooling suits, they stepped from the Solarite, each carrying, for emergency use, a small hand torch, burning atomic hydrogen, capable of melting its way through even the heavy armor of the great plane.

As they stood beside it, looking up at the gigantic wall of metal that rose sheer beside them hundreds of feet straight up, it seemed impossible that this mighty thing could fly, that it could be propelled through the air. In awed silence they gazed at its vast bulk.

Then, like pygmies beside some mighty prehistoric monster, they made their way along its side, seeking a door. Suddenly Wade stopped short and exclaimed: “Arcot, this is senseless—we can't do this! The machine is so big that it'll take us half an hour of steady walking to go around it. We'll have to use the Solarite to find an entrance!”

It was well that they followed Wade's plan, for the only entrance, as they later learned, was from the top. There, on the back of the giant, the Solarite landed—its great weight having no slightest effect on the Kaxorian craft. They found a trap-door leading down inside. However, the apparatus for opening it was evidently within the hull, so they had to burn a hole in the door before they could enter.

What a sight there was for these men of Earth. The low rumble of the idling engines was barely audible as they descended the long ladder.

There was no resemblance whatever to the interior of a flying machine; rather, it suggested some great power house, where the energies of half a nation were generated. They entered directly into a vast hall that extended for a quarter of a mile back through the great hull, and completely across the fuselage. To the extreme nose it ran, and throughout there were scattered little globes that gave off an intense white light, illuminating all of the interior. Translucent bull's-eyes obscured the few windows.

All about, among the machines, lay Venerians. Dead they seemed, the illusion intensified by their strangely blue complexions. The two Terrestrians knew, however, that they could readily be restored to life. The great machines they had been operating were humming softly, almost inaudibly. There were two long rows of them, extending to the end of the great hall. They suggested mighty generators twenty feet high. From their tops projected two-feet-thick cylinders of solid fused quartz. From these extended other rods of fused quartz, rods that led down through the floor; but these were less bulky, scarcely over eight inches thick.

The huge generator-like machines were disc-shaped. From these, too, a quartz rod ran down through the floor. The machines on the further row were in some way different; those in the front half of the row had the tubes leading to the floor below, but had no tubes jutting into the ceiling. Instead, there were many slender rods connected with a vast switchboard that covered all of one side of the great room. But everywhere were the great quartz rods, suggesting some complicated water system. Most of them were painted black, though the main rods leading from the roof above were as clear as crystal.

Arcot and Wade looked at these gigantic machines in hushed awe. They seemed impossibly huge; it was inconceivable that all this was but the power room of an airplane!

Without speaking, they descended to the level below, using a quite earthly appearing escalator. Despite the motionless figures everywhere, they felt no fear of their encountering resistance. They knew the effectiveness of Wade's anesthetic.

The hall they entered was evidently the main room of the plane. It was as long as the one above, and higher, yet all that vast space was taken by one single, titanic coil that stretched from wall to wall! Into it, and from it there led two gigantic columns of fused quartz. That these were rods, such as those smaller ones above was obvious, but each was over eight feet thick!

Short they were, for they led from one mighty generator such as they had seen above, but magnified on a scale inconceivable! At the end of it, its driving power, its motor, was a great cylindrical case, into which led a single quartz bar ten inches thick. This bar was alive with pulsing, glowing fires, that changed and maneuvered and died out over all its surface and through all its volume. The motor was but five feet in diameter and a scant seven feet long, yet obviously it was driving the great machine, for there came from it a constant low hum, a deep pitched song of awful power. And the huge quartz rod that led from the titanic coil-cylinder was alive with the same glowing fires that played through the motor rod. From one side of the generator, ran two objects that were familiar, copper bus bars. But even these were three feet thick!

The scores of quartz tubes that come down from the floor above joined, coalesced, and ran down to the great generator, and into it.

They descended to another level. Here were other quartz tubes, but these led down still further, for this floor contained individual sleeping bunks, most of them unoccupied, unready for occupancy, though some were made up.

Down another level; again the bunks, the little individual rooms.

At last they reached the bottom level, and here the great quartz tubes terminated in a hundred smaller ones, each of these leading into some strange mechanism. There were sighting devices on it, and there were ports that opened in the floor. This was evidently the bombing room.

With an occasional hushed word, the Terrestrians walked through what seemed to be a vast city of the dead, passing sleeping officers, and crewmen by the hundreds. On the third level they came at last to the control room. Here were switchboards, control panels, and dozens of officers, sleeping now, beside their instruments. A sudden dull thudding sound spun Arcot and Wade around, nerves taut. They relaxed and exchanged apologetic smiles. An automatic relay had adjusted some mechanism.

They noted one man stationed apart from the rest. He sat at the very bow, protected behind eight-inch coronium plates in which were set masses of fused quartz that were nearly as strong as the metal itself. These gave him a view in every direction except directly behind him. Obviously, here was the pilot.

Returning to the top level, they entered the long passages that led out into the titanic wings. Here, as elsewhere, the ship was brightly lighted. They came to a small room, another bunk room. There were great numbers of these down both sides of the long corridor, and along the two parallel corridors down the wing. In the fourth corridor near the back edge of the wing, there were bunk rooms on one side, and on the other were bombing posts.

As they continued walking down the first corridor, they came to a small room, whence issued the low hum of one of the motors. Entering, they found the crew sleeping, and the motor idling.

“Good Lord!” Wade exclaimed. “Look at that motor, Arcot! No bigger than the trunk of a man's body. Yet a battery of these sends the ship along at a mile a second! What power!”

Slowly they proceeded down the long hall. At each of the fifty engine mountings they found the same conditions. At the end of the hall there was an escalator that led one level higher, into the upper wing. Here they found long rows of the bombing posts and the corresponding quartz rods.

They returned finally to the control room. Here Arcot spent a long time looking over the many instruments, the controls, and the piloting apparatus.

“Wade,” he said at last, “I think I can see how this is done. I am going to stop those engines, start them, then accelerate them till the ship rolls a bit!” Arcot stepped quickly over to the pilots seat, lifted the sleeping pilot out, and settled in his place.

“Now, you go over to that board there—that one—and when I ask you to, please turn on that control—no, the one below—yes—turn it on about one notch at a time.”

Wade shook his head dubiously, a one-sided grin on his face. “All right, Arcot—just as you say—but when I think of the powers you're playing with—well, a mistake might be unhealthy!”

“I'm going to stop the motors now,” Arcot announced quietly. All the time they had been on board, they had been aware of the barely inaudible whine of the motors. Now suddenly, it was gone, and the plane was still as death!

Arcot's voice sounded unnaturally loud. “I did it without blowing the ship up after all! Now we're going to try turning the power on!”

Suddenly there was a throaty hum; then quickly it became the low whine; then, as Arcot turned on the throttle before him, he heard the tens of thousands of horsepower spring into life—and suddenly the whine was a low roar—the mighty propellers out there had became a blur—then with majestic slowness the huge machine moved off across the field!

Arcot shut off the motors and rose with a broad, relieved smile, “Easy!” he said. They made their way again up through the ship, up through the room of the tremendous cylinder coil, and then into the power room. Now the machines were quiet, for the motors were no longer working.

“Arcot, you didn't shut off the biggest machine of all down there. How come?”

“I couldn't, Wade. It has no shut-off control, and if it did have, I wouldn't use it. I will tell you why when we get back to the Solarite.”

At last they left the mighty machine; walked once more across its broad metal top. Here and there they now saw the ends of those quartz cylinders. Once more they entered the Solarite, through the air lock, and took off the cumbersome insulating suits.

As quickly as possible Arcot outlined to the two who had stayed with the Solarite, the things they had seen, and the layout of the great ship.

“I think I can understand the secret of all that power, and it's not so different from the Solarite, at that. It, too, draws its power from the sun, though in a different way, and it stores it within itself, which the Solarite does not try to do.

“Light of course, is energy, and therefore, has mass. It exerts pressure, the impact of its moving units of energy—photons. We have electrons and protons of matter, and photons of light. Now we know that the mass of protons and electrons will attract other protons and electrons, and hold them near—as in a stone, or in a solar system. The new idea here is that the photons will attract each other ever more and more powerfully, the closer they get. The Kaxorians have developed a method of getting them so close together, that they will, for a while at least, hold themselves there, and with a little 'pressure', will stay there indefinitely.

“In that huge coil and cylinder we found there we saw the main power storage tank. That was full of gaseous light-energy held together by its own attraction, plus a little help of the generator!”

“A little help?” Wade exclaimed. “Quite a little! I'll bet that thing had a million horsepower in its motor!”

“Yes—but I'll bet they have nearly fifty pounds of light condensed there—so why worry about a little thing like a million horsepower? They have plenty more where that comes from.

“I think they go up above the clouds in some way and collect the sun's energy. Remember that Venus gets twice as much as Earth. They focus it on those tubes on the roof there, and they, like all quartz tubes, conduct the light down into the condensers where it is first collected. Then it is led to the big condenser downstairs, where the final power is added, and the condensed light is stored.

“Quartz conducts light just as copper conducts electricity—those are bus bars we saw running around there.

“The bombs we've been meeting recently are, of course, little knots of this light energy thrown out by that projector mechanism we saw. When they hit anything, the object absorbs their energy—and is very promptly volatilized by the heat of the absorption.

“Do you remember that column of hissing radiance we saw shooting out of the wrecked plane just before it blew up? That was the motor connection, broken, and discharging free energy. That would ordinarily have supplied all fifty motors at about full speed. Naturally, when it cut loose, it was rather violent.

“The main generator had been damaged, no doubt, so it stopped working, and the gravitational attraction of the photons wasn't enough, without its influence to hold them bound too long. All those floods of energy were released instantaneously, of course.

“Look—there come the Lanorians now. I want to go back to Sonor and think over this problem. Perhaps we can find something that will release all that energy—though honestly, I doubt it.”

Arcot seemed depressed, overawed perhaps, by the sheer magnitude of the force that lay bound up in the Kaxorian ship. It seemed inconceivable that the little Solarite could in any way be effective against the incredible machine.

The Lanorian planes were landing almost like a flock of birds, on the wings, the fuselage, the ground all about the gigantic ship. Arcot dropped into a chair, gazing moodily into emptiness, his thoughts on the mighty giant, stricken now, but only sleeping. In its vast hulk lay such energies as intelligence had never before controlled; within it he knew there were locked the powers of the sun itself. What could the Solarite do against it?

“Oh, I almost forgot to mention it.” Arcot spoke slowly, dejectedly. “In the heat of the attack back there it went practically unnoticed. Our only weapon beside the gas is useless now. Do you remember how the ship seemed to lose its invisibility for an instant? I learned why when we investigated the ship. Those men are physicists of the highest order. We must realize the terrible forces, both physical and mental that we are to meet. They've solved the secret of our invisibility, and now they can neutralize it. They began using it a bit too late this time, but they had located the radio-produced interference caused by the ship's invisibility apparatus, and they were sending a beam of interfering radio energy at us. We are invisible only by reason of the vibration of the molecules in response to the radio impressed oscillations. The molecules vibrate in tune, at terrific frequency, and the light can pass perfectly. What will happen, however, if someone locates the source of the radio waves? It'll be simple for them to send out a radio beam and touch our invisible ship with it. The two radio waves impressed on us now will be out of step and the interference will instantly make us visible. We can no longer attack them with our atomic hydrogen blast, or with the gas—both are useless unless we can get close to them, and we can't come within ten miles of them now. Those bombs of theirs are effective at that distance.”

Again he fell silent, thinking—hoping for an idea that would once more give them a chance to combat the Kaxorians. His three companions, equally depressed and without a workable idea, remained silent. Abruptly Arcot stood up.

“I'm going to speak with the Commander-in-Field here. Then we can start back for Sonor—and maybe we had better head for home. It looks as though there is little we can do here.”

Briefly he spoke to the young Venerian officer, and told him what he had learned about the ship. Perhaps they could fly it to Sonor; or it could be left there undestroyed if he would open a certain control just before he left. Arcot showed him which one—it would drain out the power of the great storage tank, throwing it harmlessly against the clouds above. The Kaxorians might destroy the machine if they wanted to—Arcot felt that they would not wish to. They would hope, with reason, they might recapture it! It would be impossible to move that tremendous machine without the power that its “tank” was intended to hold.

---

VII

Slowly they cruised back to Sonor, Arcot still engrossed in thought. Would it be that Venus would fall before the attack of the mighty planes, that they would sweep out across space, to Earth—to Mars—to other worlds, a cosmic menace? Would the mighty machines soon be circling Earth? Guided missiles with atomic warheads could combat them, perhaps, as could the molecular motion machines. Perhaps these could be armored with twenty-inch steel walls, and driven into the great propellers, or at miles a second, into the ship itself! But these ships would require long hours, days, even weeks to build, and in that time the Kaxorian fleet would be ready. It would attack Earth within six days now! What hope was there to avert incalculable destruction—if not outright defeat?

In despair Arcot turned and strode quickly down the long hallway of the Solarite. Above him he could hear the smooth, even hum of the sweetly functioning generator, but it only reminded him of the vastly greater energies he had seen controlled that night. The thudding relays in the power room, as Wade maneuvered the ship, seemed some diminutive mockery of the giant relays he had seen in the power room of the Kaxorian plane.

He sat down in the power room, looking at the stacked apparatus, neatly arranged, as it must be, to get all this apparatus in this small space. Then at last he began to think more calmly. He concentrated on the greatest forces known to man—and there were only two that even occurred to him as great! One was the vast energies he had that very night learned of; the other was the force of the molecules, the force that drove his ship.

He had had no time to work out the mathematics of the light compression, mathematics that he now knew would give results. There remained only the molecular motion. What could he do with it that he had not done?

He drew out a small black notebook. In it were symbols, formulas, and page after page of the intricate calculus that had ended finally in the harnessing of this great force that was even now carrying him smoothly along.

Half an hour later he was still busy—covering page after page with swiftly written formulas. Before him was a great table of multiple integers, the only one like it known to exist in the System, for the multiple calculus was an invention of Arcot's. At last he found the expression he wanted, and carefully he checked his work, excitedly though now, with an expression of eager hope—it seemed logical—it seemed correct—

“Morey—oh, Morey,” he called, holding his enthusiasm in check, “if you can come here—I want you to check some math for me. I've done it—and I want to see if you get the same result independently!” Morey was a more careful mathematician than he, and it was to him Arcot turned for verification of any new discovery.

Following the general directions Arcot gave him, Morey went through the long series of calculations—and arrived at the same results. Slowly he looked up from the brief expression with which he had ended.

It was not the formula that astonished him—it was its physical significance.

“Arcot—do you think we can make it?”

There was a new expression in Arcot's eyes, a tightness about his mouth.

“I hope so, Morey. If we don't, Lanor is lost beyond a doubt—and probably Earth is, too. Wade—come here a minute, will you? Let Fuller take the controls, and tell him to push it. We have to get to work on this.”

Rapidly Arcot explained their calculations—and the proof he had gotten.

“Our beam of molecular motion-controlling energy directs all molecular motion to go at right angles to it. The mechanism so far has been a field inside a coil really, but if these figures are right, it means that we can project that field to a considerable distance even in air. It'll be a beam of power that will cause all molecules in its path to move at right angles to it, and in the direction we choose, by reversing the power in the projector. That means that no matter how big the thing is, we can tear it to pieces; we'll use its own powers, its own energies, to rip it, or crush it.

“Imagine what would happen if we directed this against the side of a mountain—the entire mass of rock would at once fly off at unimaginable speed, crashing ahead with terrific power, as all the molecules suddenly moved in the same direction. Nothing in all the Universe could hold together against it! It's a disintegration ray of a sort—a ray that will tear, or crush, for we can either make one half move away from the other—or we can reverse the power, and make one half drive toward the other with all the terrific power of its molecules! It is omnipotent—hmmm—” Arcot paused, narrowing his eyes in thought.

“It has one limitation. Will it reach far in the air? In vacuum it should have an infinite range—in the atmosphere all the molecules of the air will be affected, and it will cause a terrific blast of icy wind, a gale at temperatures far below zero! This will be even more effective here on Venus!

“But we must start designing the thing at once! Take some of the Immorpho and give me some, and we can let the sleep accumulate till we have more time! Look—we're in Sonor already! Land us, Fuller—right where we were, and then come back here. We're going to need you!”

The gorgeous display of a Venerian dawn was already coloring the east as the great buildings seemed to rise silently about them. The sky, which had been a dull luminous gray, a gray that rapidly grew brighter and brighter, was now like molten silver, through which were filtering the early rays of the intense sun. As the sun rose above the horizon, though invisible for clouds, it still was traceable by the wondrous shell pink that began to suffuse the ten mile layer of vapor. The tiny droplets were, however, breaking the clear light into a million rainbows, and all about the swiftly deepening pink were forming concentric circles of blue, of green, orange, and all the colors of the rainbow, repeated time after time—a wondrous halo of glowing color, which only the doubly intense sun could create.

“It's almost worth missing the sun all day to see their sunrises and sunsets,” Fuller commented. The men were watching it, despite their need for haste. It was a sight the like of which no Earthman had ever before seen.

Immediately, then, they plunged into the extremely complex calculation of the electrical apparatus to produce the necessary fields. To get the effect they wanted, they must have two separate fields of the director ray, and a third field of a slightly different nature, which would cause the director ray to move in one direction only. It would be disconcerting, to say the least, if the director ray, by some mistake, should turn upon them!

The work went on more swiftly than they had considered possible, but there was still much to be done on the theoretical end of the job alone when the streets about them began to fill. They noticed that a large crowd was assembling, and shortly after they had finished, after some of these people had stood there for more than an hour and a half, the crowd had grown to great size.

“From the looks of that collection, I should say we are about to become the principals in some kind of a celebration that we know nothing about. Well, we're here, and in case they want us, we're ready to come.”

The guard that always surrounded the Solarite had been doubled, and was maintaining a fairly large clear area about the ship.

Shortly thereafter they saw one of the high officials of Lanor come down the walk from the governmental building, walking toward the Solarite.

“Time for us to appear—and it may as well be all of us this time. I'll tell you what they say afterward, Wade. They've evidently gone to considerable trouble to get up this meeting, so let's cooperate. I hate to slow up the work, but we'll try to make it short.”

The four Terrestrians got into their cooling suits, and stepped outside the ship. The Lanorian dignitary left his guard, walked up to the quartet from Earth with measured tread, and halted before them.

“Earthmen,” he began in a deep, clear voice, “we have gathered here this morning to greet you and thank you for the tremendous service you have done us. Across the awful void of empty space you have journeyed forty million miles to visit us, only to discover that Venerians were making ready to attack your world. Twice your intervention has saved our city.

“There is, of course, no adequate reward for this service; we can in no way repay you, but in a measure we may show our appreciation. We have learned from the greatest psychologist of our nation, Tonlos, that in your world aluminum is plentiful, but gold and platinum are rare, and that morlus is unknown. I have had a small token made for you, and your friends. It is a little plaque, a disc of morlus, and on it there is a small map of the Solar System. On the reverse side there is a globe of Venus, with one of Earth beside it, as well as our men could copy the small globe you have given us. The northern hemisphere of each is depicted—America, your nation, and Lanor, ours, thus being shown. We want you, and each of your friends, to accept these. They are symbols of your wonderful flight across space!” The Venerians turned to each of the Terrestrians and presented each with a small metal disc.

Arcot spoke for the Terrestrians.

“On behalf of myself and my friends here, two of whom have not had an opportunity to learn your language, I wish to thank you for your great help when we most needed it. You, perhaps, have saved more than a city—you may have made it possible to save a world—our Earth. But the battle here has only begun.

“There are now in the Kaxorian camp eighteen great ships. They have been badly defeated in the three encounters they have had with the Solarite so far. But no longer will they be vulnerable to our earlier methods of attack. Your spies report that the first plane, the plane which was first attacked by the Solarite, is still undergoing repairs. These will be completed within two days, and then, when they can leave a base guard of two ships, they will attack once more. Furthermore, they will attack with a new weapon. They have destroyed the usefulness of our weapon, invisibility, and in turn, now have it to use against us! We must seek out some new weapon. I hope we are on the right track now, but every moment is precious, and we must get back to the work. This address must be short. Later, when we have completed our preliminary work, we will have to give plans to your workmen, which you will be able to turn into metal, for we lack the materials. With this help we may succeed, despite our handicap.”

The address was terminated at once. The Lanorians were probably disappointed, but they fully realized the necessity for haste.

“I wish Terrestrian orators spoke like that,” remarked Morey as they returned to the ship. “He said all there was to say, but he didn't run miles of speech doing it. He was a very forceful speaker, too!”

“People who speak briefly and to the point generally are,” Arcot said.

It was nearly noon that day before the theoretical discussion had been reduced to practical terms. They were ready to start work at once, but they had reason to work cheerfully now. Even through air they had found their ray would be able to reach thirty-five miles! They would be well out of the danger zone while attacking the gigantic planes of Kaxor.

Morey, Wade and Arcot at once set to work constructing the electrical plant that was to give them the necessary power. It was lucky indeed that they had brought the great mass of spare apparatus! They had more than enough to make all the electrical machinery. The tubes, the coils, the condensers, all were there. The generator would easily supply the power, for the terrific forces that were to destroy the Kaxorian ships were to be generated in the plane itself. It was to destroy itself; the Solarite would merely be the detonator to set it off!

---

While the physicists were busy on this, Fuller was designing the mechanical details of the projector. It must be able to turn through a spherical angle of 180 degrees, and was necessarily controlled electrically from the inside. The details of the projector were worked out by six that evening, and the numerous castings and machined pieces that were to be used were to be made in the Venerian machine shops.

One difficulty after another arose and was overcome. Night came on, and still they continued work. The Venerian workmen had promised to have the apparatus for them by ten o'clock the next morning—or what corresponded to ten o'clock.

Shortly after three o'clock that morning they had finished the apparatus, had connected all the controls, and had placed the last of the projector directors. Except for the projector they were ready, and Morey, Wade and Fuller turned in to get what sleep they could. But Arcot, telling them there was something he wished to get, took another dose of Immorpho and stepped out into the steaming rain.

A few minutes after ten the next morning Arcot came back, followed by half a dozen Venerians, each carrying a large metal cylinder in a cradle. These were attached to the landing gear of the Solarite in such fashion that the fusing of one piece of wire would permit the entire thing to drop free.

“So that's what you hatched out, eh? What is it?” asked Wade as he entered the ship.

“Just a thing I want to try out—and I'm going to keep it a deep, dark secret for a while. I think you'll get quite a surprise when you see those bombs in action! They're arranged to be released by turning current into the landing lights. We'll have to forgo lights for the present, but I needed the bombs more.

“The mechanics have finished working on your projector parts, Fuller, and they'll be over here in a short time. Here comes the little gang I asked to help us. You can direct them.” Arcot paused and scowled with annoyance. “Hang it all—when they drill into the outer wall, we'll lose the vacuum between the two walls, and all that hot air will come in. This place will be roasting in a short time. We have the molecular motion coolers, but I'm afraid they won't be much good. Can't use the generator—it's cut off from the main room by vacuum wall.

“I think we'd better charge up the gas tanks and the batteries as soon as this is done. Then tonight we'll attack the Kaxorian construction camp. I've just learned that no spy reports have been coming in, and I'm afraid they'll spring a surprise.”

Somewhat later came the sound of drills, then the whistling roar as the air sucked into the vacuum, told the men inside that the work was under way. It soon became uncomfortably hot as, the vacuum destroyed, the heat came in through all sides. It was more than the little molecular coolers could handle, and the temperature soon rose to about a hundred and fifteen. It was not as bad as the Venerian atmosphere, for the air seemed exceedingly dry, and the men found it possible to get along without cooling suits, if they did not work. Since there was little they could do, they simply relaxed.

It was nearly dark before the Lanorians had finished their work, and the gas tanks had been recharged. All that time Arcot had spent with Tonlos determining the position of the Kaxorian construction camp. Spy reports and old maps had helped, but it was impossible to do very accurate work by these means.

It was finally decided that the Kaxorian construction camp was about 10,500 miles to the southwest. The Solarite was to start an hour after dark. Travelling westward at their speed, they hoped to reach the camp just after nightfall.

---

VIII

The Solarite sped swiftly toward the southwest. The sky slowly grew lighter as the miles flashed beneath them. They were catching up with the sun. As they saw the rolling ocean beneath them give way to low plains, they realized they were over Kaxorian land. The Solarite was flying very high, and as they showed no lights, and were not using the invisibility apparatus, they were practically undetectable. Suddenly they saw the lights of a mighty city looming far off to the east.

“It's Kanor. Pass well to the west of it. That's their capital. We're on course.” Arcot spoke from his position at the projector, telling Wade the directions to follow on his course to the berth of the giant planes.

The city dropped far behind them in moments, followed by another, and another. At length, veering southward into the dusk, they entered a region of low hills, age-old folds in the crust of the planet, rounded by untold millennia of torrential rains.

“Easy, Wade. We are near now.” Mile after mile they flashed ahead at about a thousand miles an hour—then suddenly they saw far off to the east a vast glow that reached into the sky, painting itself on the eternal clouds miles above.

“There it is, Wade. Go high, and take it easy!”

Swiftly the Solarite climbed, hovering at last on the very rim of the cloud blanket, an invisible mote in a sea of gray mist. Below them they saw a tremendous field carved, it seemed, out of the ancient hills. From this height all sense of proportion was lost. It seemed but an ordinary field, with eighteen ordinary airplanes resting on it. One of these now was moving, and in a moment it rose into the air! But there seemed to be no men on all the great field. They were invisibly small from this height.

Abruptly Arcot gave a great shout. “That's their surprise! They're ready far ahead of the time we expected! If all that armada gets in the air, we're done! Down, Wade, to within a few hundred feet of the ground, and close to the field!”

The Solarite flashed down in a power dive—down with a sickening lurch. A sudden tremendous weight seemed to crush them as the ship was brought out of the dive not more than two hundred feet from the ground. Close to blacking out, Wade nevertheless shot it in as close to the field as he dared. Anxiously he called to Arcot, who answered with a brief “Okay!” The planes loomed gigantic now, their true proportions showing clearly against the brilliant light of the field. A tremendous wave of sound burst from the loudspeaker as the planes rolled across the ground to leap gracefully into the air—half a million tons of metal!

From the Solarite there darted a pale beam of ghostly light, faintly gray, tinged with red and green—the ionized air of the beam. It moved in a swift half circle. In an instant the whirr of the hundreds, thousands of giant propellers was drowned in a terrific roar of air. Great snowflakes fell from the air before them; it was white with the solidified water vapor. Then came a titanic roar and the planet itself seemed to shake! A crash, a snapping and rending as a mighty fountain of soil and rock cascaded skyward, and with it, twisting, turning, hurled in a dozen directions at once, twelve titanic ships reeled drunkenly into the air!

For a barely perceptible interval there was an oppressive silence as the ray was shut off. Then a bedlam of deafening sound burst forth anew, a mighty deluge of unbearable noise as the millions of tons of pulverized rock, humus and metal fell back. Some of it had ascended for miles; it settled amid a howling blizzard—snow that melted as it touched the madly churned airfield.

High above there were ten planes flying about uncertainly. Suddenly one of these turned, heading for the ground far below, its wings screaming their protest as the motors roared, ever faster, with the gravity of the planet aiding them. There was a rending, crackling crash as the wings suddenly bent back along the sides. An instant later the fuselage tore free, rocketing downward; the wings followed more slowly—twisting, turning, dipping in mile-long swoops.

The Solarite shot away from the spot at maximum speed—away and up, with a force that nailed the occupants to the floor. Before they could turn, behind them flared a mighty gout of light that struck to the very clouds above, and all the landscape, for miles about, was visible in the glare of the released energy.

As they turned, they saw on the plain, below a tremendous crater, in its center a spot that glowed white and bubbled like the top of a huge cauldron.

Nine great planes were circling in the air; then in an instant they were gone, invisible. As swiftly the Solarite darted away with a speed that defied the aim of any machine.

High above the planes they went, for with his radar Arcot could trace them. They were circling, searching for the Solarite.

The tiny machine was invisible in the darkness, but its invisibility was not revealed by the Kaxorian's radio detectors. In the momentary lull, Fuller asked a question.

“Wade, how is it that those ships can be invisible when they are driven by light, and have the light stored in them? They're perfectly transparent. Why can't we see the light?”

“They are storing the light. It's bound—it can't escape. You can't see light unless it literally hits you in the eye. Their stored light can't reach you, for it is held by its own attraction and by the special field of the big generators.”

They seemed to be above one of the Kaxorian planes now. Arcot caught the roar of the invisible propellers.

“To the left, Wade—faster—hold it—left—ah!” Arcot pushed a button.

Down from the Solarite there dropped a little canister, one of the bombs that Arcot had prepared the night before. To hit an invisible target is ordinarily difficult, but when that target is far larger than the proverbial side of a barn, it is not very difficult, at that. But now Arcot's companions watched for the crash of the explosion, the flash of light. What sort of bomb was it that Arcot hoped would penetrate that tremendous armor?

Suddenly they saw a great spot of light, a spot that spread with startling rapidity, a patch of light that ran, and moved. It flew through the air at terrific speed. It was a pallid light, green and wan and ghostly, that seemed to flow and ebb.

For an instant Morey and the others stared in utter surprise. Then suddenly Morey burst out laughing.

“Ho—you win, Arcot. That was one they didn't think of, I'll bet! Luminous paint—and by the hundred gallon! Radium paint, I suppose, and no man has ever found how to stop the glow of radium. That plane sticks out like a sore thumb!”

Indeed, the great luminous splotch made the gigantic plane clearly evident against the gray clouds. Visible or not, that plane was marked.

Quickly Arcot tried to maneuver the Solarite over another of the great ships, for now the danger was only from those he could not see. Suddenly he had an idea.

“Morey—go back to the power room and change the adjustment on the meteorite avoider to half a mile!” At once Morey understood his plan, and hastened to put it into effect.

The illuminated plane was diving, twisting wildly now. The Solarite flashed toward it with sickening speed, then suddenly the gigantic bulk of the plane loomed off to the right of the tiny ship, the great metal hull, visible now, rising in awesome might. They were too near; they shot away to a greater distance—then again that ghostly beam reached out—and for just a fraction of a second it touched the giant plane.

The titanic engine of destruction seemed suddenly to be in the grip of some vastly greater Colossus—a clutching hand that closed! The plane jumped back with an appalling crash, a roar of rending metal. For an instant there came the sound like a mighty buzz-saw as the giant propellers of one wing cut into the body of the careening plane. In that instant, the great power storage tank split open with an impact like the bursting of a world. The Solarite was hurled back by an explosion that seemed to rend the very atoms of the air, and all about them was a torrid blaze of heat and light that seemed to sear their faces and hands with its intensity.

Then in a time so brief that it seemed never to have happened, it was gone, and only the distant drone of the other ships' propellers came to them. There was no luminous spot. The radium paint had been destroyed in the only possible way—it was volatilized through all the atmosphere!

The Terrestrians had known what to expect; had known what would happen; and they had not looked at the great ship in that last instant. But the Kaxorians had naturally been looking at it. They had never seen the sun directly, and now they had been looking at a radiance almost as brilliant. They were temporarily blinded; they could only fly a straight course in response to the quick order of their squadron commander.

And in that brief moment that they were unable to watch him, Arcot dropped two more bombs in quick succession. Two bright spots formed in the black night. No longer did these planes feel themselves invulnerable, able to meet any foe! In an instant they had put on every last trace of power, and at their top speed they were racing west, away from their tiny opponent—in the only direction that was open to them.

But it was useless. The Solarite could pick up speed in half the time they could, and in an instant Arcot again trained his beam on the mighty splotch of light that was a fleeing plane.

Out of the darkness came a ghostly beam, for an instant of time so short that before the explosive shells of the other could be trained on it, the Solarite had moved. Under that touch the mighty plane began crumbling, then it splintered beneath the driving blow of the great wing, as it shot toward the main body of the plane at several miles a second—driving into and through it! The giant plane twisted and turned as it fell swiftly downward into the darkness—and, again there came that world-rocking explosion, and the mighty column of light.

Again and yet again the Solarite found and destroyed Kaxorian super-planes, protected in the uneven conflict by their diminutive size and the speed of their elusive maneuvering.

But to remind the men of the Solarite that they were not alone, there came a sudden report just behind them, and they turned to see that one of the energy bombs had barely fallen short! In an instant the comparative midget shot up at top speed, out of danger. It looped and turned, hunting, feeling with its every detector for that other ship. The great planes were spread out now. In every direction they could be located—and all were leaving the scene of the battle. But one by one the Solarite shot after them, and always the speed of the little ship was greater.

Two escaped. They turned off their useless invisibility apparatus and vanished into the night.

The Solarite, supported by her vertical lift units, coasted toward a stop. The drone of the fleeing super-planes diminished and was gone, and for a time the thrum of the generator and the tap-dance of relays adjusting circuits was the only sound aboard.

Wade sighed finally. “Well, gentlemen, now we've got it, what do we do with it?”

“What do you mean?” Morey asked.

“Victory. The Jack-pot. Having the devices we just demonstrated, we are now the sole owners, by right of conquest, of one highly disturbed nation of several million people. With that gadget there, we can pick it up and throw it away.

“Personally, I have a feeling that we've just won the largest white elephant in history. We don't just walk off and leave it, you know. We don't want it. But we've got it.

“Our friends in Sonor are not going to want the problem either; they just wanted the Kaxorians combed out of their hair.

“As I say—we've got it, now—but what do we do with it?”

“It's basically their problem, isn't it?” protested Fuller. Morey looked somewhat stricken, and thoroughly bewildered. “I hadn't considered that aspect very fully; I've been too darned busy trying to stay alive.”

Wade shook his head. “Look, Fuller—it was their problem before, too, wasn't it? How'd they handle it? If you just let them alone, what do you suppose they'll do with the problem this time?”

“The same thing they did before,” Arcot groaned. “I'm tired. Let's get some sleep first, anyway.”

“Sure; that makes good sense,” Wade agreed. “Sleep on it, yes. But go to sleep on it—well, that's what the not-so-bright Sonorans tried doing.

“And off-hand, I'd say we were elected. The Kaxorians undoubtedly have a nice, two thousand year old hatred for the Sonorans who so snobbishly ignored them, isolated them, and considered them unfit for association. The Sonorans, on the other hand, are now thoroughly scared, and will be feeling correspondingly vindictive. They won this time by a fluke—our coming. I can just see those two peoples getting together and settling any kind of sensible, long-term treaty of mutual cooperation!”

Arcot and Morey both nodded wearily. “That is so annoyingly correct,” Morey agreed. “And you know blasted well none of us is going to sleep until we have some line of attack on this white elephant disposal problem. Anybody any ideas?”

Fuller looked at the other three. “You know, in design when two incompatible materials must be structurally united, we tie each to a third material that is compatible with both.

“Sonor didn't win this fight. Kaxor didn't win it. Earth—in the persona of the Solarite—did. Earth isn't mad at anybody, hasn't been damaged by anybody, and hasn't been knowingly ignoring anybody.

“The Sonorans want to be let alone; it won't work, but they can learn that. I think if we run the United Nations in on this thing, we may be able to get them to accept our white elephant for us.

“They'll be making the same mistake Sonor did if they don't—knowingly ignoring the existence of a highly intelligent and competent race. It doesn't seem to work, judging from history both at home and here.”

The four looked at each other, and found agreement.

“That's something more than a problem to sleep on,” Morey said. “I'll get in touch with Sonor and tell 'em the shooting is over, so they can get some sleep too.

“It's obvious a bunch of high-power research teams are going to be needed in both countries. Earth has every reason to respect Sonoran mental sciences as well as Kaxorian light-engineering. And Earth—as we just thoroughly demonstrated—has some science of her own. Obviously, the interaction of the three is to the maximum advantage of each—and will lead to a healing of the breach that now exists.”

Arcot looked up and yawned. “I'm putting this on autopilot at twenty miles up, and going to sleep. We can kick this around for a month anyway—and this is not the night to start.”

“The decision is unanimous,” Wade grinned.

---

BOOK THREE