"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 deg. 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

THE BLACK STAR PASSES



PROLOGUE

Taj Lamor gazed steadily down at the vast dim bulk of the ancient city spread out beneath him. In the feeble light of the stars its mighty masses of up-flung metal buildings loomed strangely, like the shells of some vast race of crustacea, long extinct. Slowly he turned, gazing now out across the great plaza, where rested long rows of slender, yet mighty ships. Thoughtfully he stared at their dim, half-seen shapes.

Taj Lamor was not human. Though he was humanoid, Earth had never seen creatures just like him. His seven foot high figure seemed a bit ungainly by Terrestrial standards, and his strangely white, hairless flesh, suggesting unbaked dough, somehow gave the impression of near-transparency. His eyes were disproportionately large, and the black disc of pupil in the white corneas was intensified by contrast. Yet perhaps his race better deserved the designation homo sapiens than Terrestrians do, for it was wise with the accumulated wisdom of uncounted eons.

He turned to the other man in the high, cylindrical, dimly lit tower room overlooking the dark metropolis, a man far older than Taj Lamor, his narrow shoulders bent, and his features grayed with his years. His single short, tight-fitting garment of black plastic marked him as one of the Elders. The voice of Taj Lamor was vibrant with feeling:

"Tordos Gar, at last we are ready to seek a new sun. Life for our race!"

A quiet, patient, imperturbable smile appeared on the Elder's face and the heavy lids closed over his great eyes.

"Yes," he said sadly, "but at what cost in tranquility! The discord, the unrest, the awakening of unnatural ambitions—a dreadful price to pay for a questionable gain. Too great a price, I think." His eyes opened, and he raised a thin hand to check the younger man's protest. "I know—I know—in this we do not see as one. Yet perhaps some day you will learn even as I have that to rest is better than to engage in an endless struggle. Suns and planets die. Why should races seek to escape the inevitable?" Tordos Gar turned slowly away and gazed fixedly into the night sky.

Taj Lamor checked an impatient retort and sighed resignedly. It was this attitude that had made his task so difficult. Decadence. A race on an ages-long decline from vast heights of philosophical and scientific learning. Their last external enemy had been defeated millennia in the past; and through easy forgetfulness and lack of strife, ambition had died. Adventure had become a meaningless word.

Strangely, during the last century a few men had felt the stirrings of long-buried emotion, of ambition, of a craving for adventure. These were throwbacks to those ancestors of the race whose science had built their world. These men, a comparative handful, had been drawn to each other by the unnatural ferment within them; and Taj Lamor had become their leader. They had begun a mighty struggle against the inertia of ages of slow decay, had begun a search for the lost secrets of a hundred-million-year-old science.

Taj Lamor raised his eyes to the horizon. Through the leaping curve of the crystal clear roof of their world glowed a blazing spot of yellow fire. A star—the brightest object in a sky whose sun had lost its light. A point of radiance that held the last hopes of an incredibly ancient race.

The quiet voice of Tordos Gar came through the semidarkness of the room, a pensive, dreamlike quality in its tones.

"You, Taj Lamor, and those young men who have joined you in this futile expedition do not think deeply enough. Your vision is too narrow. You lack perspective. In your youth you cannot think on a cosmic scale." He paused as though in thought, and when he continued, it seemed almost as though he were speaking to himself.

"In the far, dim past fifteen planets circled about a small, red sun. They were dead worlds—or rather, worlds that had not yet lived. Perhaps a million years passed before there moved about on three of them the beginnings of life. Then a hundred million years passed, and those first, crawling protoplasmic masses had become animals, and plants, and intermediate growths. And they fought endlessly for survival. Then more millions of years passed, and there appeared a creature which slowly gained ascendancy over the other struggling life forms that fought for the warmth of rays of the hot, red sun.

"That sun had been old, even as the age of a star is counted, before its planets had been born, and many, many millions of years had passed before those planets cooled, and then more eons sped by before life appeared. Now, as life slowly forced its way upward, that sun was nearly burned out. The animals fought, and bathed in the luxury of its rays, for many millennia were required to produce any noticeable change in its life-giving radiations.

"At last one animal gained the ascendancy. Our race. But though one species now ruled, there was no peace. Age followed age while semi-barbaric peoples fought among themselves. But even as they fought, they learned.

"They moved from caves into structures of wood and stone—and engineering had its beginning. With the buildings came little chemical engines to destroy them; warfare was developing. Then came the first crude flying-machines, using clumsy, inefficient engines. Chemical engines! Engines so crude that one could watch the flow of their fuel! One part in one hundred thousand million of the energy of their propellents they released to run the engines, and they carried fuel in such vast quantities that they staggered under its load as they left the ground! And warfare became world-wide. After flight came other machines and other ages. Other scientists began to have visions of the realms beyond, and they sought to tap the vast reservoirs of Nature's energies, the energies of matter.

"Other ages saw it done—a few thousand years later there passed out into space a machine that forced its way across the void to another planet! And the races of the three living worlds became as one—but there was no peace.

"Swiftly now, science grew upon itself, building with ever faster steps, like a crystal which, once started, forms with incalculable speed.

"And while that science grew swiftly greater, other changes took place, changes in our universe itself. Ten million years passed before the first of those changes became important. But slowly, steadily our atmosphere was drifting into space. Through ages this gradually became apparent. Our worlds were losing their air and their water. One planet, less favored than another, fought for its life, and space itself was ablaze with the struggles of wars for survival.

"Again science helped us. Thousands of years before, men had learned how to change the mass of matter into energy, but now at last the process was reversed, and those ancestors of ours could change energy into matter, any kind of matter they wished. Rock they took, and changed it to energy, then that energy they transmuted to air, to water, to the necessary metals. Their planets took a new lease of life!