"How much more have you got to do before you can start sending?"

"Not an awful lot. Everything built—all I've got to do is assemble it. I should be able to do it easily in a week. Hope nothing else happens—if I drag you into any more such messes as those we've just been getting out of by the skin of our teeth, I'll begin to wish that we had started out at first to drift it back to Tellus in the Hope. Let's see how much time we've got. We should start shooting one day after an eclipse, so that we'll have five days to send. You see, we don't want to point our beam too close to Jupiter or to any of the large satellites, because the enemy might live there and might intercept it. We had an eclipse yesterday—so one week from today, at sunrise, I start shooting."

"But Earth's an evening star now; you can't see it in the morning."

"I'm not going to aim at Tellus. I'm shooting at Brandon, and he's never there for more than a week or two at a stretch. They're prowling around out in space somewhere almost all the time."

"Then how can you possibly hope to hit them?"

"It may be quite a job of hunting, but not as bad as you might think. They probably aren't much, if any, outside the orbit of Mars, and they usually stay within a couple of million kilometers or so of the Ecliptic, so we'll start at the sun and shoot our beam in a spiral to cover that field. We ought to be able to hit them inside of twelve hours, but if we don't, we'll widen our spiral and keep on trying until we do hit them."

"Heavens, Steve! Are you planning on telegraphing steadily for days at a time?"

"Sure, but not by hand, of course—I'll have an automatic sender and automatic pointers."

Stevens had at his command a very complete machine-shop, he had an ample supply of power, and all that remained for him to do was to assemble the parts which he had built during the long journey from Titan to Ganymede. Therefore, at sunrise of the designated day, he was ready, and, with Nadia hanging breathless over his shoulder, he closed the switch, a toothed wheel engaged a delicate interrupter, and a light sounder began its strident chatter.

"Ganymede point oh four seven ganymede point oh four seven ganymede point oh four seven..." endlessly the message was poured out into the ether, carried by a tight beam of ultra-vibrations and driven by forces sufficient to propel it well beyond the opposite limits of the orbit of Mars.

"What does it say? I can't read code."

Stevens translated the brief message, but Nadia remained unimpressed.

"But it doesn't say anything!" she protested. "It isn't addressed to anybody, it isn't signed—it doesn't tell anybody anything about anything."

"It's all there, ace. You see, since the beam is moving sidewise very rapidly at that range and we're shooting at a small target, the message has to be very short or they won't get it all while the beam's on 'em—it isn't as though we were broadcasting. It doesn't need any address, because nobody but the Sirius can receive it—except possibly the Jovians. They'll know who's sending it without any signature. It tells them that Ganymede wants to receive a message on the ultra-band centering on forty-seven thousandths. Isn't that enough?"

"Maybe. But suppose some of them live right here on Ganymede—you'll be shooting right through the ground all night—or suppose that even if they don't live here, that they can find our beam some way? Or suppose that Brandon hasn't got his machine built yet, or suppose that it isn't turned on when our beam passes them, or suppose they're asleep then? A lot of things might happen."

"Not so many, ace—your first objection is the only one that hasn't got more holes in it than a sieve, so I'll take it first. Since our beam is only a meter in diameter here and doesn't spread much in the first few million kilometers, the chance of direct reception by the enemy, even if they do live here on Ganymede, is infinitesimally small. But I don't believe that they live here—at least, they certainly didn't land on this satellite. As you suggest, however, it is conceivable that they may have detector screens delicate enough to locate our beam at a distance; but since in all probability that means a distance of hundreds of thousands of kilometers, I think it highly improbable. We've got to take the same risk anyway, no matter what we do, whenever we start to use any kind of driving power, so there's no use worrying about it. As for your last two objections, I know Brandon and I know Westfall. Brandon will have receivers built that will take in any wave possible of propagation, and Westfall, the cautious old egg, will have them running twenty-four hours a day, with automatic recorders, finders, and everything else that Brandon can invent—and believe me, sweetheart, that's a lot of stuff!"

"It's wonderful, the way you three men are," replied Nadia thoughtfully, reading between the lines of Stevens' utterance. "They knew that you were on the Arcturus, of course—and they knew that if you were alive you'd manage in some way to get in touch with them. And you, away out here after all this time, are superbly confident that they are expecting a call from you. That, I think, is one of the finest things I ever heard of."

"They're two of the world's best—absolutely." Nadia looked at him, surprised, for he had not seen anything complimentary to himself in her remark. "Wait until you meet them. They're men, Nadia—real men. And speaking of meeting them—please try to keep on loving me after you meet Norm Brandon, will you?"

"Don't be a simp!" her brown eyes met his steadily. "You didn't mean that—you didn't even say it, did you?"

"Back it comes, sweetheart! But knowing myself and knowing those two...."

"Stop it! If Norman Brandon or Quincy Westfall had been here instead of you, or both of them together, we'd have been here from now on—we wouldn't even have gotten away from the Jovians!"

* * * * *

"Now it's your turn to back water, guy!"

"Well, maybe, a little—if both of them were here, they ought to equal you in some things. Brandon says himself that he and Westfall together make one scientist—Dad says he says so."

"You don't want to believe everything you hear. Neither of them will admit that he knows anything or can do anything—that's the way they are."

"Dad has told me a lot about them—how they've always been together ever since their undergraduate days. How they studied together all over the world, even after they'd been given all the degrees loose. How they even went to the other planets to study—to Mars, where they had to live in space-suits all the time, and to Venus, where they had to take ultra-violet treatments every day to keep alive. How they learned everything that everybody else knew and then went out into space to find out things that nobody else ever dreamed of. How you came to join them, and what you three have done since. They're fine, of course—but they aren't you," she concluded passionately.

"No, thank Heaven! I know you love me, Nadia, just as I love you—you know I never doubted it. But you'll like them, really. They're a wonderful team. Brandon's a big brute, you know—fully five centimeters taller than I am, and he weighs close to a hundred kilograms—and no lard, either. He's wild, impetuous, always jumping at conclusions and working out theories that seem absolutely ridiculous, but they're usually sound, even though impractical. Westfall's the practical member—he makes Norm pipe down, pins him down to facts, and makes it possible to put his hunches and wild flashes of genius into workable form. Quince is a...."

"Now you pipe down! I've heard you rave so much about those two—I'd lots rather rave about you, and with more reason. I wish that sounder would start sounding."

"Our first message hasn't gone half way yet. It takes about forty minutes for the impulse to get to where I think they are, so that even if they got the first one and answered it instantly, it would be eighty minutes before we'd get it. I sort of expect an answer late tonight, but I won't be disappointed if it takes a week to locate them."

"I will!" declared the girl, and indeed, very little work was done that day by either of the castaways.

Slowly the day wore on, and the receiving sounder remained silent. Supper was eaten as the sun dropped low and disappeared, but they felt no desire to sleep. Instead, they went out in front of the steel wall, where Stevens built a small campfire. Leaning back against the wall of their vessel, they fell into companionable silence, which was suddenly broken by Stevens.

"Nadia, I just had a thought. I'll bet four dollars I've wasted a lot of time. They'll certainly have automatic relays on Tellus, to save me the trouble of hunting for them, but like an idiot I never thought of it until just this minute, in spite of the speech I made you about them. I'm going to change those directors right now."

"That's quite a job, isn't it?"

"No, only a few minutes."

"Do it in the morning; you've done enough for one day—maybe you've hit them already, any way."

They again became silent, watching Jupiter, an enormous moon some seven degrees in apparent diameter.

"Steve, I simply can't get used to such a prodigious moon! Look at the stripes, and look at that perfectly incredible...."

A gong sounded and they both jumped to their feet and raced madly into the Hope. The ultra-receiver had come to life and the sounder was chattering insanely—someone was sending with terrific speed, but with perfect definition and spacing.

"That's Brandon's fist—I'd know his style anywhere," Stevens shouted, as he seized notebook and pencil.

"Tell me what it says, quick, Steve!" Nadia implored.

"Can't talk—read it!" Stevens snapped. His hand was flying over the paper, racing to keep up with the screaming sounder.

"...ymede all x stevens ganymede all x stevens ganymede all x placing and will keep sirius on plane between you and tellus circle fifteen forty north going tellus first send full data spreading beam to cover circle fifteen forty quince suggests possibility this message intercepted and translated personally I think such translation impossible and that he is wilder than a hawk but just in case they should be supernaturally intelligent...."

Stevens stopped abruptly and stared at the vociferous sounder.

"Don't stop to listen—keep on writing!" commanded Nadia.

"Can't," replied the puzzled mathematician. "It doesn't make sense. It sounds intelligent—it's made up of real symbols of some kind or other, but they don't mean a thing to me."

"Oh, I see—he's sending mush on purpose. Read the last phrase!"

"Oh, sure—'mush' is right," and with no perceptible break the signals again became intelligible.

"... if they can translate that they are better scholars than we are signing off until hear from you brandon."

* * * * *

The sounder died abruptly into silence and Nadia sobbed convulsively as she threw herself into Stevens' arms. The long strain over, the terrible uncertainty at last dispelled, they were both incoherent for a minute—Nadia glorifying the exploits of her lover, Stevens crediting the girl herself and his two fellow-scientists with whatever success had been achieved. A measure of self-control regained, Stevens cut off his automatic sender, changed the adjustments of his directors and cut in his manually operated sending key.

"What waves are you using, anyway?" asked Nadia, curiously. "They must be even more penetrating than Roeser's Rays, to have such a range, and Roeser's Rays go right through a planet without even slowing up."

"They're of the same order as Roeser's—that is, they're sub-electronic waves of the fourth order—but they're very much shorter, and hence more penetrating. In fact, they're the shortest waves yet known, so short that Roeser never even suspected their existence."

"Suppose there's a Jovian space-ship out there somewhere that intercepts our beams. Couldn't they locate us from it?"

"Maybe, and maybe not—we'll just have to take a chance on that. That goes right back to what we were talking about this morning. They might be anywhere, so the chance of hitting one is very small. It isn't like hitting the Sirius, because we knew within pretty narrow limits where to look for her, and even at that we had to hunt for her for half a day before we hit her. We're probably safe, but even if they should have located us, we'll probably be able to hide somewhere until the Sirius gets here. Well, the quicker I get busy sending the dope, the sooner they can get started."

"Tell them to be sure and bring me all my clothes they can find, a gallon of perfume, a barrel of powder, and a carload of Delray's Fantasie chocolates—I've been a savage so long that I want to wallow in luxury for a while."

"I'll do that—and I want some real cigarettes!"

Stevens first sent a terse, but complete account of everything that had happened to the Arcturus, and a brief summary of what he and Nadia had done since the cutting up of the IPV. The narrative finished, he launched into a prolonged and detailed scientific discussion of the enemy and their offensive and defensive weapons. He dwelt precisely and at length upon the functioning of everything he had seen. Though during the long months of their isolation he had been too busy to do any actual work upon the weapons of the supposed Jovians, yet his keen mind had evolved many mathematical and physical deductions, hypotheses, and theories, and these he sent out to the Sirius, concluding:

"There's all the dope I can give you. Figure it out, and don't come at all until you can come loaded for bear; they're bad medicine. Call us occasionally, to keep us informed as to when to expect you, but don't call too often. We don't want them locating you, and if they should locate us through your ray or ours, it would be just too bad. So-long. Stevens and Newton."

Nadia had insisted upon staying up and had been brewing pot after pot of her substitutes for coffee while he sat at the key; and it was almost daylight when he finally shut off the power and arose, his right arm practically paralyzed from the unaccustomed strain of hours of telegraphing.

"Well, sweetheart, that's that!" he exclaimed in relief. "Brandon and Westfall are on the job. Nothing to do now but wait, and study up on our own account on those Jovians' rays. This has been one long day for us, though, little ace, and I suggest that we sleep for about a week!"



CHAPTER VIII

Callisto to the Rescue

All humanity of Callisto, the fourth major satellite of Jupiter, had for many years been waging a desperate and apparently hopeless defense against invading hordes of six-limbed beings. Every city and town had long since been reduced to level fields of lava by the rays of the invaders. Every building and every trace of human civilization had long since disappeared from the surface of the satellite. Far below the surface lay the city of Zbardk, the largest of the few remaining strongholds of the human race. At one portal of the city a torpedo-shaped, stubby-winged rocket plane rested in the carriage of a catapult. Near it the captain addressed briefly the six men normally composing his crew.

"Men, you already know that our cruise today is not an ordinary patrol. We are to go to One, there to destroy a base of the hexans. We have perhaps one chance in ten thousand of returning. Therefore I am taking only one man—barely enough to operate the plane. Volunteers step one pace forward."

The six stepped forward as one man, and a smile came over the worn face of their leader as he watched them draw lots for the privilege of accompanying him to probable death. The two men entered the body of the torpedo, sealed the openings and waited.

"Free exits?" snapped the Captain of the Portal, and twelve keen-eyed observers studied minutely screens and instrument panels connected to the powerful automatic lookout stations beneath the rims of the widely separated volcanic craters from which their craft could issue into Callisto's somber night.

"No hexan radiation can be detected from Exit Eight," came the report. The Captain of the Portal raised an arm in warning, threw in the guides, and the two passengers were hurled violently backward, deep into their cushioned seats, as the catapult shot their plane down the runway. As the catapult's force was spent automatic trips upon the undercarriage actuated the propelling rockets and mile after mile, with rapidly mounting velocity, the plane sped through the tube. As the exit was approached, the tunnel described a long vertical curve, so that when the opening into the shaft of the crater was reached and the undercarriage was automatically detached, the vessel was projected almost vertically upward. Such was its velocity and so powerful was the liquid propellant of its rocket motors, that the eye could not follow the flight of the warship as it tore through the thin layer of the atmosphere and hurled itself out into the depths of space.

"Did we get away?" asked the captain, hands upon his controls and eyes upon his moving chart of space.

"I believe so, sir," answered the other officer, at the screens of the six periscopic devices which covered the full sphere of vision. "No reports from the rim, and all screens blank." Once more a vessel had issued from the jealously secret city of Zbardk without betraying its existence to the hated and feared hexans.

For a time the terrific rocket motors continued the deafening roar of their continuous explosions, then, the desired velocity having been attained, they were cut out and for hours the good ship "Bzark" hurtled on through the void at an enormous but constant speed toward the distant world of One, which it was destined never to reach.

"Captain Czuv! Hexan radiation, coordinates twenty two, fourteen, area six!" cried the observer, and the commander swung his own telescopic finder into the indicated region. His hands played over course and distance plotters for a brief minute, and he stared at his results in astonishment.

"I never heard of a hexan traveling that way before," he frowned. "Constant negative acceleration and in a straight line. He must think that we have been cleared out of the ether. Almost parallel to us and not much faster—even at this long range, it is an easy kill unless he starts dodging, as usual."

As he spoke, he snapped a switch and from a port under the starboard wing there shot out into space a small package of concentrated destruction—a rocket-propelled, radio-controlled torpedo. The rockets of the tiny missile were flaming, but that flame was visible only from the rear and no radio beam was upon it. Czuv had given it precisely the direction and acceleration necessary to make it meet the hexan sphere in central impact, provided that sphere maintained its course and acceleration unchanged.

"Shall I direct the torpedo in the case the hexan shifts?" asked the officer.

"I think not. They can, of course, detect any wave at almost any distance, and at the first sign of radioactivity they would locate and destroy the bomb. They also, in all probability, would destroy us. I would not hesitate to attack them on that account alone, but we must remember that we are upon a more important mission than attacking one hexan ship. We are far out of range of their electro-magnetic detectors, and our torpedo will have such a velocity that they will have no time to protect themselves against it after detection. Unless they shift in the next few seconds, they are lost. This is the most perfect shot I ever had at one of them, but one shot is all I dare risk—we must not betray ourselves."

* * * * *

Course, lookout, and rank forgotten, the little crew of two stared into the narrow field of vision, set at its maximum magnification. The instruments showed that the enemy vessel was staying upon its original course. Very soon the torpedo came within range of the detectors of the hexans. But as Captain Czuv had foretold, the detection was a fraction of a second too late, rapidly as their screens responded, and the two men of Zbardk uttered together a short, fierce cry of joy as a brilliant flash of light announced the annihilation of the hexan vessel.

"But hold!" The observer stared into his screen. "Upon that same line, but now at constant velocity, there is still a very faint radiation, of a pattern I have never seen before."

"I think ... I believe ..." the captain was studying the pattern, puzzled. "It must be low frequency, low-tension electricity, which is never used, so far as I know. It may be some new engine of destruction, which the hexan was towing at such a distance that the explosion of our torpedo did not destroy it. Since there are no signs of hexan activity and since it will not take much fuel, we shall investigate that radiation."

Tail and port-side rockets burst into roaring activity and soon the plane was cautiously approaching the mass of wreckage, which had been the IPV Arcturus.

"Human beings, although of some foreign species!" exclaimed the captain, as his vision-ray swept through the undamaged upper portion of the great liner and came to rest upon Captain King at his desk.

Although the upper ultra-lights of the Terrestrial vessel had been cut away by the hexan plane of force, jury lights had been rigged, and the two commanders were soon trying to communicate with each other. Intelligible conversation was, of course, impossible, but King soon realized that the visitors were not enemies. At their pantomimed suggestion he put on a space-suit and wafted himself over to the airlock of the Callistonian warplane. Inside the central compartment, the strangers placed over his helmet a heavily wired harness, and he found himself instantly in full mental communication with the Callistonian commander. For several minutes they stood silent, exchanging thoughts with a rapidity impossible in any language; then, dressed in space-suits, both leaped lightly across the narrow gap into the still open outer lock of the terrestrial liner. King watched Czuv narrowly after the pressure began to collapse his suit, but the stranger made no sign of distress. He had been right in his assurance that the extra pressure would scarcely inconvenience him. King tore off his helmet, issued a brief order, and soon every speaker in the Arcturus announced:

"All passengers and all members of the crew except lookouts on duty will assemble immediately in Saloon Three to discuss a possible immediate rescue."

The subject being one of paramount interest, it was a matter of minutes until the full complement of two hundred men and women were in the main saloon, clinging to hastily rigged hand lines, closely packed before the raised platform upon which were King and Czuv, wired together with the peculiar Callistonian harness. To most of the passengers, familiar with the humanity of three planets, the appearance of the stranger brought no surprise; but many of them stared in undisguised amazement at his childish body, his pale, almost colorless skin, his small, weak legs and arms, and his massive head.

"Ladies and gentlemen!" Captain King opened the meeting. "I introduce to you Captain Czuv, of the scout cruiser Bzarvk, of the only human race now living upon the fourth large satellite of Jupiter, which satellite we know as Callisto. I am avoiding their own names as much as possible, because they are almost unpronounceable in English or Interplanetarian. This device that you see connecting us is a Callistonian thought transformer, by means of which any two intelligent beings can converse without language. Our situation is peculiar, and in order that you may understand fully what lies ahead of us, the captain will now speak to you, through me—that is, what follows will be spoken by Captain Czuv, of the Bzarvk, but he will be using my vocal organs."

"Friends from distant Tellus," King's voice went on, almost without a break, "I greet you. I am glad, for your sake as well as our own, that your vessel was able to destroy the hexan ship holding you captive, and whose crew would have killed you all as soon as they had landed your vessel and had read your minds. I regret bitterly that we can do so little for you, for only the representatives of a human civilization being exterminated by a race of highly intelligent monsters can fully realize how desirable it is for all the various races of humanity to assist and support each other. In order that you may understand the situation, it is necessary that I delve at some length into ancient history, but we have ample time. In about ..." he broke off, realizing that the two races had no thought in common in the measure of time.

"One-half time of rotation of Great Planet upon axis?" flashed from Czuv's brain, and "About five hours," King's mind flashed back.

"It will be about five hours before any steps can be taken, so that I feel justified in using a brief period for explanation. In the evolution of the various forms of life upon Callisto, two genera developed intelligence far ahead of all others. One genus was the human, as you and I; the other the hexan. This creature, happily unknown to you of the planets nearer our common sun, is the product of an entirely different evolution. It is a six-limbed animal, with a brain equal to our own—one perhaps in some ways superior to our own. They have nothing in common with humanity, however; they have few of our traits and fewer of our mental processes. Even we who have fought them so long can scarcely comprehend the chambers of horror that are their minds. Even were I able to paint a sufficiently vivid picture with words, you of Earth could not begin to understand their utter ruthlessness and inhumanity, even among themselves. You would believe that I was lying, or that my viewpoint was warped. I can say only that I hope most sincerely that none of you will ever get better acquainted with them."

* * * * *

"Ages ago, then, the human and the hexan developed upon all four of the major satellites of the Great Planet, which you know as Jupiter, and upon the north polar region of Jupiter itself. By what means the two races came into being upon worlds so widely separated in space we know not—we only know it to be the fact. Human life, however, could not long endure upon Jupiter. The various human races, after many attempts to meet conditions of life there by variations in type fell before the hexans; who, although very small in size upon the planet, thrived there amazingly. Upon the three outer satellites humanity triumphed, and many hundreds of cycles ago the hexans of those satellites were wiped out, save for an occasional tribe of savages of low intelligence who lived in various undesirable portions of the three worlds. For ages then there was peace upon Callisto. Here is the picture at that time—upon Jupiter the hexans; upon Io hexans and humans, waging a ceaseless and relentless war of mutual extermination; upon the three outer satellites humanity in undisturbed and unthreatened peace. Five worlds, each ignorant of life upon any other.

"As I have said, the hexans of Jupiter were, and are, diabolically intelligent. Driven probably by their desire to see what lay beyond their atmosphere of eternal cloud, to the penetration of which their eyesight was attuned, they developed the space-ship; and effected a safe landing, first upon the barren, airless moonlet nearest them, and then upon fruitful Io. There they made common cause with the hexans against the humans, and in space of time Ionian humanity ceased to exist. Much traffic and interbreeding followed between the hexans of Jupiter and those of Io, resulting in time in a race intermediate in size between the parent stocks and equally at home in the widely variant air pressures and gravities of planet and satellite. Soon their astronomical instruments revealed the cities of Europa to their gaze, and as soon as they discovered that the civilization of Europa was human, they destroyed it utterly, with the insatiable blood lust that is their heritage.

"In the meantime the human civilizations of Ganymede and Callisto had also developed instruments of power. Observing the cities upon the other satellites, many scientists studied intensively the problem of space navigation, and finally there was some commerce between the two outer satellites at favorable times. Finally, vessels were also sent to Io and to Europa, but none of them returned. Knowing then what to expect, Ganymede and Callisto joined forces and prepared for war. But our science, so long attuned to the arts of peace, had fallen behind lamentably in the devising of more and ever more deadly instruments of destruction. Ganymede fell, and in her fall we read our own doom. Abandoning our cities, we built anew underground. Profiting from lessons learned full bloodily upon Ganymede, we resolved to prolong the existence of the human race as long as possible.

"The hexans were, and are masters of the physical science. They command the spectrum in a way undreamed of. Their detectors reveal etheric disturbances at unbelievable distances, and they have at their beck and call forces of staggering magnitude. Therefore in our cities is no electricity save that which is wired, shielded, and grounded; no broadcast radio; no source whatever of etheric disturbances save light—and our walls are fields of force which we believe to be impenetrable to any searching frequency capable of being generated. Now I am able to picture to you the present.

"We are the last representatives of the human race in the Jovian planetary system. Our every trace upon the surface has been obliterated. We are hiding in our holes in the ground, coming out at night by stealth so that our burrows shall not be revealed to the hexans. We are fighting for time in which our scientists may learn the secrets of power—and fearing, each new day, that the enemy may have so perfected their systems of rays that they will be able to detect us and destroy us, even in our underground and heavily shielded retreats, by means of forces even more incomprehensible than those they are now employing.

"Therefore, friends, you see how little we are able to do for you, we a race fighting for our very existence and doomed to extinction save for a miracle. We cannot take you to Callisto, for it is besieged by the hexans and the driving forces of your lifeboats, practically broadcast as they are, would be detected and we should all be destroyed long before we could reach safety. Captain King and I have pondered long and have been able to see only one course of action. We are drifting at constant velocity, using no power, and with all save the most vitally necessary machinery at rest. Thus only may we hope to avoid detection during the next two hours.

"Our present course will take us very close to Europa, which the hexans believe to be like Ganymede, entirely devoid of civilized life. Its original humanity was totally destroyed, and all its civilized hexans are finding shelter from our torpedoes upon Jupiter until we of Callisto shall likewise have been annihilated. The temperature of Europa will suit you. Its atmosphere, while less dense than that to which you are accustomed, will adequately support your life. If we are not detected in the course of the next few hours we can probably land upon Europa in safety, since its neighborhood is guarded but loosely. In fact, we have a city there, as yet unsuspected by the hexans, in which our scientists will continue to labor after Callisto's civilization shall have disappeared. We think that it will be safe to use your power for the short time necessary to effect a landing. We shall land in a cavern, in a crater already in communication with our city. In that cavern, instructed and aided by some of us, you will build a rocket vessel—no rays can be used because of the hexans—in which you will be able to travel to a region close enough to your earth so that you can call for help. You will not be able to carry enough fuel to land there—in fact, nearly all the journey will have to be made without power, traveling freely in a highly elongated orbit around the sun—but if you escape the hexans, you should be able to reach home safely, in time. It is for the consideration of this plan that this meeting has been called."

* * * * *

"Just one question," Breckenridge spoke. "The hexans are intelligent. Why are they leaving Europa and Ganymede so unguarded that human beings can move back there and that we can land there, all undetected?"

"I will answer that question myself," replied King. "Captain Czuv did not quite do justice to his own people. It is true that they are being conquered, but for every human life that is taken, a thousand hexans die, and for every human ship that is lost, twenty hexan vessels are annihilated in return. While the hexans are masters of rays, the humans are equally masters of explosives and of mechanisms. They can hit a perfect score upon any target in free space whose course and acceleration can be determined, at any range up to five thousand kilometers, and they have explosives thousands of times as powerful as any known to us. Ray screens are effective only against rays, and the hexans cannot destroy anything they cannot see before it strikes them. So it is that all the hexan vessels except those necessary to protect their own strongholds, are being concentrated against Callisto. They cannot spare vessels to guard uselessly the abandoned satellites. Because of the enormously high gravity of Jupiter the hexans there are safe from human attack save for ineffectual long-range bombardment, but Io is being attacked constantly and it is probable that in a few more years Io also will be an abandoned world. Some of you may have received the impressions that the hexans are to triumph immediately, but such an idea is wrong. The humans can, and will, hold out for a hundred years or more unless the enemy perfects a destructive ray of the type referred to. Even then, I think that our human cousins will hold out a long time. They are able men, fighters all, and their underground cities are beautifully protected."

There was little argument. Most of the auditors could understand that the suggested course was the best one possible. The remainder were so stunned by the unbelievable events of the attack that they had no initiative, but were willing to follow wherever the more valiant spirits led. It was decided that no attempt should be made to salvage any portion of the Arcturus, since any such attempt would be fraught with danger and since the wreckage would be of little value. The new vessel was to be rocket driven and was to be built of Callistonian alloys. Personal belongings were moved into lifeboats, doors were closed, and there ensued a painful period of waiting and suspense.

The stated hour was reached without event—no hexan scout had come close enough to them to detect the low-tension radiation of the vital machinery of the Arcturus, cut as it was to the irreducible minimum and quite effectively grounded as it was by the enormous mass of her shielding armor. At a signal from Captain Czuv the pilot of each lifeboat shot his tiny craft out into space and took his allotted place in the formation following closely behind the Bzarvk, flying toward Europa, now so large in the field of vision that she resembled more a world than a moon. Captain King, in the Callistonian vessel, transmitted to Breckenridge the route and flight data given him by the navigator of the winged craft. The chief pilot, flying "point," in turn relayed more detailed instructions to the less experienced pilots of the other lifeboats.

Soon the surface of Europa lay beneath them; a rugged, cratered, and torn topography of mighty ranges of volcanic mountains. Most of the craters were cold and lifeless; but here and there a plume of smoke and steam betrayed the presence of vast, quiescent forces. Straight down one of those gigantic lifeless shafts the fleet of space craft dropped—straight down a full two miles before the landing signal was given. At the bottom of the shaft a section of the rocky wall swung aside, revealing the yawning black mouth of a horizontal tunnel. At intervals upon its roof there winked into being almost invisible points of light. Along that line of lights the lifeboats felt their way, coming finally into a huge cavern, against one sheer metal wall of which they parked in an orderly row. Roll was called, and the terrestrials walked, as well as they could in the feeble gravity of the satellite, across the vast chamber and into a conveyance somewhat resembling a railway coach, which darted away as soon as the doors were shut. For hundreds of miles that strange tunnel extended, and as the car shot along door after door of natural rock opened before it, and closed as soon as it had sped through. In spite of the high velocity of the vehicle, it required almost two hours to complete the journey. Finally, however, it slowed to a halt and the Terrestrial visitors disembarked at a portal of the European city of the Callistonians.

"Attention!" barked Captain King. "The name of this city, as nearly as I can come to it in English, is WRUZK. 'Roosk' comes fairly close to it and is easier to pronounce. We must finish our trip in small cars, holding ten persons each. We shall assemble again in the building in which we have been assigned quarters. The driver of each car will lead his passengers to the council room in which we shall meet."

"Oh, what's the use—this is horrible, horrible—we might as well die!" a nervous woman shrieked, and fainted.

"Such a feeling is, perhaps, natural," King went on, after the woman had been revived and quiet had been restored, "but please control it as much as possible. We are alive and well, and will be able to return to Tellus eventually. Please remember that these people are putting themselves to much trouble and inconvenience to help us, desperate as their own situation is, and conduct yourselves accordingly."

The rebuke had its effect, and with no further protest the company boarded the small cars, which shot through an opening in the wall and into a street of that strange subterranean city. Breckenridge, in the last car to leave the portal, studied his surroundings with interest as his conveyance darted through the gateway. More or less a fatalist by nature and an adventurer, of course, since no other type existed among the older spacehounds of the IPC, he was intensely interested in every new phase of their experience, and was no whit dismayed or frightened.

* * * * *

He found himself seated in a narrow canoe of metal, immediately behind the pilot, who sat at a small control panel in the bow. Propelled by electro-magnetic fields above a single rail, upon lightly touching and noiseless wheels, the terrestrial pilot saw with keen appreciation the manner in which switch after switch ahead of them obeyed the impulses sent ahead from the speeding car. The streets were narrow and filled with monorails; pedestrians pursued their courses upon walks attached to the walls of the buildings, far above the level of the streets. The walls were themselves peculiar, rising as they did stark, unbroken, windowless expanses of metal, merging into and supporting a massive roof of the same silvery metal. Walls and roof alike reflected a soft, yet intense, white light. Soon a sliding switch ahead of them shot in and simultaneously an opening appeared in the blank metal wall of a building. Through the opening the street-car flew, and as the pilot slowed the canoe to a halt, the door slid smoothly shut behind them. Parking the car beside a row of its fellows, the Callistonian driver indicated that the Terrestrials were to follow him and led the way into a large hall. There the others from the Arcturus were assembled, facing Captain King, who was standing upon a table.

"Fellow travelers," King addressed them, "our course of action has been decided. There are two hundred three of us. There will be twenty sections of ten persons, each section being in charge of one of the officers of the Arcturus. Doctor Penfield, our surgeon, a man whose intelligence, fairness, and integrity are unquestioned, will be in supreme command. His power and authority will be absolute, limited only by the Callistonian Council. He will work in harmony with the engineer, who is to direct the entire project of building the new vessel. Each of you will be expected to do whatever he can—the work you will be asked to do will be well within your powers, and you will each have ample leisure for recreation, study, and amusement, of all of which you will find unsuspected stores in this underground community. You will each be registered and studied by physicians, surgeons, and psychologists; and each of you will have prescribed for him the exact diet that is necessary for his best development. You will find this diet somewhat monotonous, compared to our normal fare of natural products, since it is wholly synthetic; but that is one of the minor drawbacks that must be endured. Chief Pilot Breckenridge and I will not be with you. In some small and partial recompense for what they are doing for us all, he and I are going with Captain Czuv to Callisto, there to see whether or not we can aid them in any way in the fight against the hexans. One last word—Doctor Penfield's rulings will be the products of his own well-ordered mind after consultation and agreement with the Council of this city, and will be for the best good of all. I do not anticipate any refusal to cooperate with him. If, however, such refusal should occur, please remember that he is a despot with absolute power, and that anyone obstructing the program by refusing to follow his suggestions will spend the rest of his time here in confinement and will go back to Tellus in irons, if at all. In case Chief Pilot Breckenridge and I should not see you again, we bid you goodbye and wish you a safe voyage—but we expect to go back with you."

Brief farewells were said and captain and pilot accompanied Czuv to one of the little street-cars. Out of the building it dashed and down the crowded but noiseless thoroughfare to the portal. Signal lights flashed briefly there and they did not stop, but tore on through the portal and the tunnel, with increasing speed.

"Don't have to transfer to a big car, then?" asked Breckenridge.

"No," King made answer. "Small cars can travel these tubes as well as the large ones, and on much less power. In the city the wheels touch the rails lightly, not for support, but to make contacts through which traffic signals are sent and received. In the tunnels the wheels do not touch at all, as signaling is unnecessary—the tunnels being used infrequently and by but one vehicle at a time. No trolleys, tracks, or wires are visible, you notice. Everything is hidden from any possible visiray of the hexans."

"How about their power?"

"I don't understand it very well—hardly at all, in fact."

"It is quite simple." To the surprise of both Terrestrials, Czuv was speaking English, but with a strong and very peculiar accent; slighting all the vowels and accenting heavily the consonant sounds. "The car no longer requires my attention, so I am now free to converse. You are surprised at my knowing your language? You will speak mine after a few more applications of the thought exchanger. I am speaking with a vile accent, of course, but that is merely because my vocal organs are not accustomed to making vowel sounds. Our power is obtained by the combustion of gases in highly efficient turbines. It is transmitted and used as direct current, our generator and motors being so constructed that they can produce no etheric disturbances capable of penetrating the shielding walls of our city. The city was built close to deposits of coal, oil, and gas of sufficient amount to support our life for thousands of years; for from these deposits come power, food, clothing, and all the other necessities and luxuries of our lives. Strong fans draw air from various extinct craters, force it through ventilating ducts into every room and recess of the city, and exhaust it into the shaft of a quiescent volcano, in whose gaseous outflow any trace of our activities is, of course, imperceptible. For obvious reasons no rockets or combustion motors are used in the city proper."

* * * * *

Thus Captain Czuv explained to the Terrestrials his own mode of life, and received from them in turn full information concerning Earthly life, activity, and science. Long they talked, and it was almost time to slow down for the journey's end when the Callistonian brought the conversation back to their immediate concerns.

"My lieutenant and I were upon a mission of some importance, but it is more important to take you to Callisto, for there may be many things in which you can help us. Not in rays—we know all the vibrations you have mentioned and several others. The enemy, however, is supreme in that field, and until our scientists have succeeded in developing ray-screens, such as are used by the hexans, it would be suicidal to use rays at all. Such screens necessitate the projection of pure, yet dirigible, forces—you do not have them upon your planet?"

"No, and so far as I know such screens are also unknown upon Mars and Venus, with whose inhabitants we are friendly."

"The inhabitants of all the planets should be friendly; the solar system should be linked together in intercourse for common advancement. But that is not to be. The hexans will eventually triumph here, and a Jovian system peopled by hexans will have no intercourse with any human civilization save that of internecine war. We, of Callisto, have only one hope—or is it really a hope? In the South Polar country of Jupiter, there dwells a race of beings implacably hostile to the hexans. They seem to invade the country of the hexans frequently, even though they are apparently repulsed each time. Our emissaries to the South Polar country, however, have never returned—those beings, whatever they are, if not actively inimical, certainly are not friendly toward us."

"You know nothing of their nature?"

"Nothing, since our electrical instruments are not sufficiently sensitive to give us more than a general idea of what is transpiring there, and vision is practically useless in that eternal fog. We know, however, that they are far advanced in science, and we are thankful indeed that none of their frightful flying fortresses have been launched against us. They apparently are not interested in the satellites, and it is no doubt due to their unintentional assistance that we have survived as long as we have."

In the cavern at last, the three men boarded the Callistonian space-plane and were shot up the crater's shaft. The voyage to Callisto was uneventful, even uninteresting save at its termination. The Bzarvk, coated every inch as it was with a dull, dead black, completely absorptive outer coating, entered the thin layer of Callisto's atmosphere in darkest night, with all rockets dead, with not a light showing, and with no apparatus of any kind functioning. Utterly invisible and undetectable, she dove downward, and not until she was well below the crater's rim did the forward rockets burst into furious life. Then the Terrestrials understood another reason for the immense depth of those shafts other than that of protection from the detectors of the enemy—all that distance was necessary to overcome the velocity of their free fall without employing a negative acceleration greater than the frail Callistonian bodies could endure. From the cavern at the foot of the shaft, a regulation tunnel extended to the Callistonian city of Zbardk. Portal and city were very like Wruszk, upon distant Europa, and soon the terrestrial captain and pilot were in conference with the Council of Callisto.

* * * * *

Months of Earthly time dragged slowly past, months during which King and Breckenridge studied intensively the offensive and defensive systems of Callisto without finding any particular in which they could improve them to any considerable degree. Captain Czuv and his warplane still survived, and it was while the Callistonian commander was visiting his terrestrial guests, that King voiced the discontent that had long affected both men.

"We're both tired of doing nothing, Czuv. We have been of little real benefit, and we have decided that your ideas of us are all wrong. We are convinced that our personal horsepower can be of vastly more use to you than our brain-power, which doesn't amount to much. Your whole present policy is one of hiding and sniping. I think that I know why, but I want to be sure. Your vessels carry lots of fuel—why can the hexans outrun you?" Thus did King put his problem.

"They can stand enormously higher accelerations than we can. The very strongest of us loses consciousness at an acceleration of twenty-five meters per second per second, no matter how he is braced, and that is only a little greater than the normal gravity of our enemies upon Jupiter. Their vessels at highest power develop an acceleration of thirty-five meters, and the hexans themselves can stand much more than even that high figure," replied Czuv.

"I thought so. Assume that you traveled at forty-five. Would it disable you permanently, or would you recover as soon as it was lowered?"

"We would recover promptly, unless the exposure had been unduly prolonged. Why?"

"Because," said King, "I can stand an acceleration of fifty-four meters for two hours, and Breckenridge here tests fifty two meters. I can navigate anything, and Breckenridge can observe as well as any of your own men. Build a plane to accelerate at forty-five meters and we will blow those hexans out of the ether. You will have to revive and do the shooting, however—your gunnery is entirely beyond us."

"That is an idea of promise, and one that had not occurred to any of us," Czuv replied and work was begun at once upon the new flyer.

When the super-plane was ready for its maiden voyage, its crew of three studied it as it lay in the catapult at the portal. Dead black as were all the warplanes, its body was twice as large as that of the ordinary vessel, its wings were even more stubby, and its accommodations had been cut to a minimum to make room for the enormous stores of fuel necessary to drive the greatly increased battery of rocket motors and for the extra supply of torpedoes carried. Waving to the group of soldiers and citizens gathered to witness the take-off of the new dreadnought of space, the three men entered the cramped operating compartment, strapped themselves into their seats, and were shot away. As usual the driving rockets were cut off well below the rim of the shaft, and the vessel rose in a long and graceful curve, invisible in the night. Such was its initial velocity and so slight was the force of gravity of the satellite that they were many hundreds of miles from the exit before they began to descend, and Breckenridge studied his screens narrowly for signs of hexan activity.

"Do you want to try one of your long-range shots when we find one of them?" the pilot asked Czuv.

"No, it would be useless. Between deflection by air-currents and the dodging of the enemy vessels, our effective range is shortened to a few kilometers, and their beams are deadly at that distance. No, our best course is to follow the original plan—to lure them out into space at uniform acceleration, where we can destroy them easily."

"Right," and Breckenridge turned to King, who was frowning at his controls. "How does she work on a dead stick, Chief?"

"Maneuverability about minus ten at this speed and in this air. She'd have to have at least fifteen hundred kilometers an hour to be responsive out here. See anything yet?"

"Not yet ... wait a minute! Yes, there's one now—P-12 on area five. Give us all the X10 and W27 you can, without using power—we want to edge over close enough so that she can't help but see us when we start the rockets."

"Be sure and stay well out of range. I'm giving her all she'll take, but she won't take much. With these wings she has the gliding angle of a kitchen sink."

"All x—I'm watching the range, close. Wish we had instruments like these on the IPV's. We'll have to install some when we get back. All x! Give her the gun—level and dead ahead!"

Half the battery of rockets burst into their stuttering, explosive roar of power and the vessel darted away in headlong flight.

"He sees us and is after us—turn her straight up!"

A searing, coruscating finger of flame leaped toward them, but their calculations had been sound—the hexan was harmless at that extreme range. King, under the pilot's direction, kept the plane at a safe distance from the sphere while the satellite grew smaller and smaller behind them and Czuv lapsed quietly into unconsciousness.

"He's been out for quite a while. Far enough?" asked King.

"All x now, I guess—don't believe they can see the flash from here. Cut!"

The rockets died abruptly and a blast from the side ports threw the plane out of the beam—and once out of it, beyond range of the electro-magnetic detectors as they were their coating of absolute black rendered the craft safe from observation. One dirigible rocket remained in action, its exhaust hidden from the enemy by the body of the vessel, and Captain Czuv soon recovered his senses.

"Wonderful, gentlemen!" he exclaimed, as he manipulated the delicate controls of his gunnery panel. "This is the first time in history that a Callistonian vessel has escaped from a hexan by speed alone."

An instantaneously extinguished flare of incandescence marked the passing of the hexan sphere into nothingness, and the cruiser shot back toward Callisto in search of more prey. It was all too plentiful, and twenty times the drama was reenacted before approaching day made it necessary for Czuv to take the controls and dive the vessel into the westermost landing-shaft of Zbardk. A rousing and enthusiastic welcome awaited them, and joy spread rapidly when their success became known.

"Now we know what to do, and we had better do it immediately, before they get our system figured out and increase their own power." King reported to the Council. "You might send a couple of ships to Europa and bring back as many of the Tellurian officers as want to come and can be spared from the work there. They all test above forty-five meters, and they can learn this stuff in short order. While they're coming, your engineers can be building more ships like this one."

The new vessel did not make another voyage until nine sister ships were ready and manned, each with two Terrestrial officers and one Callistonian gunner. All ten took to the ether at once, and the hexan fleet melted away like frost-crystals before a summer sun. A few weeks of carnage and destruction and not a hexan was within range of the detectors of Callisto—they were gone!

"This is the first time in years that Callisto's air has been free of the hexans," Czuv said, thoughtfully. "With your help we have reduced their strength to a fraction of what it was, but they have not given up. They will return, with a higher acceleration than even you Terrestrials, powerful as you are, can stand."

"Certainly they will, but you will be no worse off than you were before—you can return to your own highly effective tactics."

"We are infinitely better off for your help. You have given us a new lease on life...."

He broke off as a flaring light sprang into being upon the portal board and the observer of Exit One made his report—there was a hexan vessel in the air, location 425 over VJ-42.

"There's one left! Let us get him! No, he's ours!" Confused shouts arose from the bull-pen; but the original superplane was at the top of the call-board and accordingly King, Breckenridge, and Czuv embarked upon an expedition more hazardous far than they had supposed—an expedition whose every feature was relayed to those in the portal by the automatic lookouts upon the rims and which was ended before a single supporting Callistonian plane could be launched.

For the enemy vessel was not the last of the low-powered hexan vessels, as everyone had supposed—it was the first of the high-powered craft, arriving long before its appearance was expected. Before its terrific acceleration and savage onslaught, the superplane might as well have been stationary and unarmed. After his long dive downward, King could not even leave the atmosphere—the hexan was upon them within a few seconds, even though the stupendous battery of rockets, full driven, had roared almost instantly into desperate action. Bomb after bomb Breckenridge hurled, with full radio control, fighting with every resource at his command, but in vain. The frightful torpedoes were annihilated in mid-flight; and nose, tail-assembly, and wings were sheared neatly from the warplane by a sizzling plane of force. Side rockets and torpedo tubes were likewise sliced away and the helpless body of the Callistonian cruiser, falling like a plummet, was caught and held by a tractor ray. Captor and captive settled toward the ground.

"This is a signal honor," observed Captain Czuv when he had revived. "It has been many, many cycles since they have taken Callistonians captive. They kill us at every opportunity. Is it your custom to destroy yourselves in a situation such as this?"

"It is not. While we live there is hope."

"Not ours. Unless they have made enormous strides in psychological mechanisms, they cannot tear from our minds any secrets we really wish to keep. That is useless," he went on, as King lifted a hand-weapon. "You will have no opportunity whatever to use it," and he was right.

A searing beam of energy drove them out of the vessel, then electro-magnetic waves burned every metallic object out of their possession. Burning rays herded them into the hexan sphere and into a small room, whose door clanged shut behind them.

"Ah, two are humans of a strange breed!" a snarling voice barked from the wall, in the Callistonian language. "Our deductions were accurate, as usual—it is to the humans of Planet Three, whose bodies are a trifle less puny than those of the humanity of the satellites, that we owe our recent reverses. However, those reverses were merely temporary—humanity, no matter what its breed, shall very shortly disappear from the satellites. Now, you scum of the Solar System, you shall be permitted to witness an entrancing spectacle on the way to our headquarters, where all your knowledge is to be taken from you before you die, lingeringly and horribly. There is a strange space-vessel nearing us probably searching for the one we took and which you dogs of Callisto must have been fortunate enough to take from us before we could study and kill its human cargo. Watch its destruction and cringe—and know, in your suffering, that the more you suffer, the greater shall be our enjoyment."

"I believe that," King acknowledged. As all three prisoners stared at the wall-screen, upon which was pictured a huge football of scarred grey steel, Czuv was amazed to see the faces of Breckenridge and King light up with fierce smiles of pleasure and anticipation.

"You dissemble well," remarked the Callistonian. "That will rob them of much pleasure."

"They'll get robbed of more than that," King returned. "This is too good to keep, and since they cannot understand English, I'll tell you something. I told you about Stevens. He apparently wasn't killed, as we thought. He must have escaped, and there is the result. That ship there is far from innocent—her being so far out of range of any of our power-plants proves that. That vessel is the Sirius—the research laboratory of the IPC—the Inter-Planetary Corporation! It carries the greatest scientific minds of three of the inner planets, and it is loaded with pure poison or it wouldn't be here. Oh, you hexans, what you have got coming to you!"

* * * * *



Concluding a Thrilling New Serial of Interplanetary Life and Travel by Edward E. Smith, Ph.D.

Author of "Skylark of Space," and "Skylark Three"

PART III

Spacehounds of IPC

The question of rays—their expanding power for good and evil—is receiving increasing attention from scientists. The x-ray has been found to be very beneficial, given in certain quantities, but extremely inimical to health, and even fatal, if too much exposure is given. The powers of the cosmic rays have not been fully discovered as yet. And there is no reason to doubt the theory that there may be found still more destructive and powerful rays. Even wars are becoming a more dangerous plaything for nations of our world—to say nothing of other possible enemies from other parts of our universe. Stevens and Nadia Newton meet with thrilling experiences galore in this concluding instalment.

What Went Before:

The Interplanetary Vessel Arcturus sets out for Mars, with Breckenridge as chief pilot, carrying on board, besides its regular crew and some passengers, the famous Dr. Stevens, designer of space ships and computer. He checks computations made by astronomers stationed in floating observatories, and after he has located any trouble and suggests a plan for minimizing the hazards of the trip from the earth to Mars he reports his findings and suggestions to Mr. Newton, chief of the Interplanetary Corporation.

Stevens then takes Nadia, Mr. Newton's beautiful young daughter, on a specially conducted sight-seeing tour of the Arcturus and thoroughly explains to her all of the works of the vessel. Nadia has herself had a good science education. While they are down at the bottom of the ship—nearing the end of their tour—Stevens feels a barely perceptible movement of the vessel from its course. When he turns on the visiplate, he is horrified to find that a mysterious ray of unparalleled power has neatly sliced the Arcturus in several places.

Nadia and Stevens are completely separated from the rest of the crew and passengers of the ship, so they get into a lifeboat, which is equipped for a limited amount of space travel. Despite the strict and apparently effective vigilance of the enemy destroyer, Stevens and Nadia make their getaway in the lifeboat, which they aptly call "Forlorn Hope," and finally make a safe landing on Ganymede, where Stevens almost completes a power-plant and a radio transmitter, to enable him to communicate with the earth or with the IPV Sirius, which is used by Westfall and Brandon (two of the world's best scientists) as a floating laboratory.

They start for Cantrell's Comet, where Stevens acquires the necessary material for his giant transmitting tube, heads back to Ganymede, when their ship is cut, top and bottom, by a strong ray-beam. Stevens and Nadia soon find that the other ship is manned by friendly beings from Saturn. Together they plan against their common foes—the Hexans—who are enemies of the universe. After helping the Saturnians to repair their power plant, they start back to Ganymede, aided by their new friends from the frigid civilization. Finally, however, Stevens succeeds in connecting, by radio, with the Sirius and his scientist friends on board it, who rush to the aid of the two castaways. It is while the castaways are captives of the Hexans that help looms near.



CHAPTER IX

The Sirius Takes a Hand

The Sirius loafed along through the ether at normal acceleration just outside the orbit of Mars and a million miles north of the ecliptic plane. In the control room, which had been transformed into a bewilderingly complete laboratory, Norman Brandon strode up and down, waving his arms, his unruly black hair on end, addressing savagely his friend and fellow-scientist, who sat unmoved and at ease.

"For cat's sake, Quince, let's get busy! They're outside somewhere, since the police have scoured every cubic kilometer within range of the power plants without finding a trace of them. We've got the power question licked right now—with these fields we can draw sixty thousand kilofranks from cosmic radiation, which is lots more than we'll ever need. We haven't drawn a frank from a plant in a month, and we've had to cut our field strength down to a whisper to keep from burning out our accumulators. We can hunt as far as Neptune easy—we can go to Alpha Centauri if we want to. This thing of piffling and monkeying around here's pulling my cork, and for the ten thousand four hundred and sixty seventh time I say let's prowl and prowl now! In fact, I'm getting so sick of sticking around doing nothing that I'm going out anyway, if I have to go alone in a lifeboat!"



Impetuous and violent as Brandon had always been, never before had he gone to such lengths as to suggest a disruption of the partnership; and Westfall, knowing that Brandon, in his most violent moments, never threatened idly, thought long before he replied.

"You will not go alone, of course. If you insist upon going without further preparation I will go too, no matter how foolish I think such a course to be. We have power, it is true, but in all other respects we are in no condition to meet an opponent having command of such resources as must certainly be possessed by those who attacked the Arcturus. Our detectors are inefficient, our system of vision is crude, to say the least, and many other things are still in the experimental stage. We have not the slightest idea whom or what we may encounter. It is all too probable that we would simply be throwing away uselessly the lives of more good men. It is also foolish from a general viewpoint, for as you already know, we and our assistants happen to be in better position to study these things than is any one else at the present time. However, I will compromise with you. We can learn much in a month if you will really try, instead of wasting time in fuming around the ship and indulging in these idiotic tantrums. If you will buckle down and really study the problems confronting us for thirty days, we will set out at the end of that time, ready or not."

"All x. I hate to do it, but we've been together too long to bust it up now," and Brandon turned toward his bench. Scarcely had he reached it when a series of dots and dashes roared from an amplifier. Both men leaped for the receiver which had so unexpectedly burst into sound, reaching it just as it relapsed into silence, and from the tape of the recorder they read the brief message.

"...h four seven ganymede point oh four seve...."

"That's Steve!" yelled Brandon. "Nobody else could build an ultra-sender! Direction?"

"No need of calculating distance or direction. Ganymede is the third major satellite of Jupiter."

"Sure. Of course, Quince—never thought of that. Dope enough—point oh four seven."

As Stevens had told Nadia, the message was completely informing to those for whom it was intended, and soon Brandon's answer was flying toward the distant satellite. He then started to call the officers of the Inter-planetary Corporation, but was restrained by his conservative friend.

"It would be better to wait a while, Norman. In a few hours we will know what to tell them."

At high acceleration the Sirius drove toward the Jupiter-Earth-North plane, and Brandon calculated from his own bearings and from the current issue of the "Ephemeris" the time at which Stevens' reply should be received. Two minutes before that time he was pacing up and down in front of the ultra-receiver, and fifteen seconds after it he snapped:

"Come on, Perce, get busy! Shake a leg!"

"Oh, come, Norman; give him a few minutes' leeway, at least," said Westfall, with amused tolerance. "Even if your calculations are that accurate—which of course they are," he added hastily at a stormy glance from hot black eyes, "since we received that message direct, instead of through one of our relay stations, Stevens probably has been throwing it around for hours or perhaps days, looking for us, and the shock of hearing from us at last might well have put him out of control for a minute or two."

The carrier wave hissed into the receiver, forestalling Brandon's fiery reply, followed closely by the code signals they had been expecting. As soon as the story had been told, and while Brandon was absorbed in the scientific addenda of Stevens, Westfall thoughtfully called up Newton, Nadia's father.

"Nadia is alive, free, safe, well, and happy," he shot out without preliminary or greeting, as soon as the now lined features of the director showed upon the communicator screen, and the careworn countenance smoothed magically into the keen face of the fighting Newton of old, as Westfall recounted rapidly the tale of the castaways.

"They apparently have not suffered in any way," he concluded. "All that Stevens wants is some cigarettes, and your daughter's needs, while somewhat more numerous than his, seem to be only clothes, powder, perfume, and candy. Therefore we need not worry about them. The fate of the others is still unknown, but there seems to be a slight possibility that some of them may yet be rescued. You may release as much or as little of this story as may seem desirable. Stevens is still sending data of a highly technical nature. We shall arrive there at 21:32 next Tuesday."

* * * * *

In due time the message from Ganymede ended and Brandon, with many pages of his notebook crammed with figures and equations, snapped off the power of the receiver and turned to his bench. Gone was the storming, impetuous rebel; his body was ruled solely by the precise and insatiable brain of the research scientist.

"He's great, that kid Perce! When I see him, I'm going to kiss him on both cheeks. He's got enough dope on them to hang them higher than Franklin's kite, and we'll nail those jaspers to the cross or I'm a polyp! He's crazier than a loon in most of his hunches, but he's filled four of our biggest gaps. There is such a thing, as a ray-screen, you kill-joy, and there are also lifting or tractor rays—two things I've been trying to dope out and that you've been giving me the Bronx cheer on. The Titanians have had a tractor ray for ages—he sent me complete dope on it—and the Jovians have got them both. We'll have them in three days, and it ought to be fairly simple to dope out the opposite of a tractor, too—a pusher or presser beam. Say, round up the gang, will you, while I'm licking some of this stuff into shape for you to tear apart? Where are Venus and Mars? Um ... m ... m. Tell Alcantro and Fedanzo to come over here pronto—give 'em a special if necessary. We'll pick up Dol Kenor and Pyraz Amonar on the way—no, get them to Tellus, too. Then we'll get action quicker. Those four are all I want—get anybody else you want to come along."

His hands playing over the keys of an enormous calculating machine, Brandon was instantly immersed in a profound mathematico-physical problem; deaf and blind to everything about him. Westfall, knowing well that far-reaching results would follow Brandon's characteristic attack, sat down at the controls of the communicator. He first called Mars, the home planet of Alcantro and Fedanzo, the foremost force-field experts of three planets; and was assured in no uncertain terms that those rulers of rays were ready and anxious to follow wherever Brandon and Westfall might lead. Thence to Venus, where Dol Kenor, the electrical wizard, and Pyraz Amonar, the master of mechanism, also readily agreed to accompany the expedition. He then called the General-in-Chief of the Interplanetary Police, requesting a detail of two hundred picked men for the hazardous venture. These most important calls out of the way, he was busy for over an hour giving long-distance instructions so that everything would be in readiness for the servicing of the immense space-cruiser the following Tuesday night.

Having guarded against everything his cautious and far-seeing mind could envisage, he went over to Brandon's desk and sat down, smoking contemplatively until the idea had been roughed out in mathematical terms.

"Here's the rough draft of the ray screen, Quince. We generate a blanket frequency, impressed upon the ultra carrier wave. That's old stuff, of course. Here's the novelty, in equation 59. With two fields of force, set up from data 27 to 43, it will be possible actually to project a pure force of such a nature that it will react to de-heterodyne the blanketing frequency at any predetermined distance. That, of course, sets up a barrier against any frequency of the blanketed band. Incidentally, an extension of the same idea will enable us to see anywhere we want to look—calculate a retransmitting field."

"One thing at a time, please. That screen may be possible, but those fields will never generate it. Look at datum 31, in which your assumptions are unsound. In order to make any solution at all possible you have assumed cosine squared theta negligible. Mathematically, it is of course vanishingly small compared to the first power of the cosine, but fields of that type must be exact, and your neglect of the square is indefensible. Since you cannot integrate with the squared term in place, your whole solution fails."

"Not necessarily. We'll go back to 29, and put in sine squared theta minus one equal to z sub four. That gives us a coversed sine in 30, and then we integrate...."

Thus the argument raged, and all the assistants whose work was not too pressing gathered around unobtrusively, for it was from just such fierce discussions as this that the ultra-radio and other epoch-making discoveries had come into being. Yard after yard of calculator paper was filled with equations and computations. Weirdly shaped curves were drawn, with arguments at every point—arguments hot and violent from Brandon, from Westfall cold and precise, backed by lightning calculations and with facts and diagrams culled from the many abstruse works of reference, which by this time literally covered the bench and overflowed upon the floor.

It was in this work that the strikingly different temperaments and abilities of the two scientists were revealed. Brandon never stood still, but walked around jerkily, chewing savagely the stem of an ancient and reeking pipe, gesticulating vigorously, the while his keen and agile mind was finding a way over, around, or through the apparently insuperable obstacles which beset their path; by means of mathematical and physical improvisations, which no one not inspired by sheer genius could have evolved. Westfall, seated quietly at the calculator, mercilessly shredded Brandon's theories to ribbons, pointing out their many flaws with his cold, incisive reasoning and with rapid calculations of the many factors involved. Then Brandon would find a remedy for each weakness in turn and, when Westfall could no longer find a single flaw in the structure, they would toss the completed problem upon a table and attack the next one with unabated zeal. Brandon, in his light remark that the two made one real scientist, had far understated the case—those two brains, each so powerful and each so perfectly complementing the other, comprised the master-scientist who was to revolutionize science completely in a few short years.

To such good purpose did they labor that the calculations were practically finished by the time they reached the earth. There the ship was serviced with a celerity that spoke volumes for the importance of her mission—even the Aldebaran, the dazzlingly gold-plated queen of the fleet, waited unattended and disregarded on minus time while the entire force of the Interplanetary Corporation concentrated upon the battle-scarred old hulk of the Sirius. Brandon was surprised when he saw the two companies of police, but characteristically accepted without question the wisdom of any decision of his friend, and cordially greeted Inspector-General Crowninshield, only a year or so older than himself, but already in charge of a Division.

"Keen-looking bunch, Crown. Lot of different outfits—volunteers for special duty from the whole Tellurian force?"

"Yes. Everybody wanted to go, and there threatened to be trouble over the selection, so we picked the highest ratings from the whole Service. If there ever was such a thing as a picked force, we shall have it with us."

"What d'you mean, 'us'? You aren't going, are you?"

"Try to keep me from it! The names of all five of us I-G's were put in a hat, and I was lucky."

"Well, you may come in handy, at that," Brandon conceded. "And here's the big boss himself. Hi, Chief!"

"Ho, Brandon! Ho, Westfall!" Newton, Chairman of the Board of Directors of the IPC, shook hands with the two scientists. "Your Martians and Venerians are in Lounge Fifteen. I suppose that you have a lot of things to thrash out, so you may as well start now. Everything is being attended to—I'll take charge now."

"You going along, too?" asked Brandon.

"Going along, too? I'm running this cruise!" Newton declared. "I may take advice from you on some things and from Crowninshield on others, but I am in charge!"

"All x—it's a relief, at that," and Brandon and Westfall went to join their fellow-scientists in the designated room of the space-cruiser.

* * * * *

What a contrast was there as the representatives of three worlds met! All six men were of the same original stock or of a similar evolution—science has not, even yet, decided the question definitely. Their minds were very much alike, but their respective environments had so variantly developed their bodily structures that to outward seeming they had but little in common.

Through countless thousands of generations the Martians had become acclimated to a planet having little air, less water, and characterized by abrupt transitions from searing heat to bitter cold: from blinding light to almost impenetrable darkness. Eight feet tall and correspondingly massive, they could barely stand against the gravitational force of the Earth, almost three times as great as that of Mars, but the two Martian scientists struggled to their feet as the Terrestrials entered.

"As you were, fellows—lie down again and take it easy." Brandon suggested in the common Interplanetarian tongue. "We'll be away from here very soon, then we can ease off."

"We greet our friends standing as long as we can stand," and, towering a full two feet above Brandon's own six-feet-two, Alcantro and Fedanzo in turn engulfed his comparatively tiny hand in a thick-shelled paw and lifted briefly the inner lids of quadruply-shielded eyes. For the Martian skin is not like ours. It is of incredible thickness; dry, pliable, rubbery, and utterly without sensation: heavily lined with fat and filled throughout its volume with tiny air-cells which make it an almost perfect non-conductor of heat and which prevent absolutely the evaporation of the precious moisture of the body. For the same reasons their huge and cat-like eyes are never exposed, but look through sealed, clear windows of membrane, over which may be drawn at will one or all of four pairs of lids—lids transparent, insensible, non-freezable, air-spaced insulators. Even the air they exhale carries from their bodies a minimum of the all-important heat and moisture, for the passages of their nostrils do not lead directly to the lungs, as do ours. They are merely the intakes for a tortuous system of tubes comprising a veritable heat-exchanger, so that the air finally expelled is in almost perfect equilibrium with the incoming supply in temperature and in moisture content. A grayish tan in color, naked and hairless—though now, out of deference to Terrestrial conventions, wearing light robes of silk—indifferent alike to any extreme of heat or cold, light or darkness: such were the two forbidding beings who arose to greet their Terrestrial friends, then again reclined.

"I suppose that you have been given to drink?" Westfall made sure that they had been tendered the highest hospitality of Mars.

"We have drunk full deeply, thanks; and it was not really necessary, for we drank scarcely three weeks ago."

Brandon and Westfall turned then and greeted the two Venerians, as different from the Martians as they were from the Terrestrials. Of earthly stature, form, and strength, yet each was encased in a space-suit stretched like a drum-head, and would live therein or in the special Venerian rooms of the vessel as long as the journey should endure. For the atmosphere of Venus is more than twice as dense as ours, is practically saturated with water-vapor, carries an extremely high concentration of carbon dioxide, and in their suits and rooms is held at a temperature of one hundred and ten degrees Fahrenheit. The lenses of their helmets were of heavy, yellowish-red composition, protecting their dead-white skins and red eyes from all actinic rays—for the Venerian lives upon the bottom of an everlasting sea of fog and his thin epidermis, utterly without pigmentation, burns and blisters as frightfully at the least exposure to actinic light as does ours at the touch of a red-hot iron.

Out in space at last, cruising idly with the acceleration set at a point bearable for the Martians, Westfall called the meeting to order and outlined the situation facing them. Brandon then handed around folios of papers, upon which the Venerians turned the invisible infra-red beams of the illuminators upon their helmets, thus flooding them with the "light" to which their retinas were most responsive.

"Here's the data," Brandon began. "As you see from Sheet 1, we can already draw any amount of power we shall need from cosmic radiation alone...."

"Perpetual motion—ridiculous!" snapped from the sending disk upon the helmet of the master of mechanism.

"Not at all, Amonar," put in his fellow Venerian, "any more than a turbo-generator at the foot of a waterfall is perpetual motion. Those radiations originate we know not where, probably as a result of intra-atomic reactions. The fields of force of our hosts merely intercept these radiations, as a water-driven turbine intercepts the water. We merely use a portion of their energy before permitting them to go on, to we know not what end. Truly you have made a notable achievement in science, Tellurian friends, and we congratulate you upon its accomplishment. Please proceed."

"Upon the following sheets are described the forces employed by the Jovians, as we shall call them until we find out who or what they really are. We will discuss these forces later. For each force we have already calculated a screen, and we have also calculated various other forces of our own, with which we hope to arm ourselves before we reach Ganymede. The problems facing us are complex, since there are some nine thousand forcebands of the order in which we are working, each differing from all the others as much as torque differs from tension, or as much as red differs from green. Therefore we have appealed to you for help, knowing that we could do but little alone. Alcantro and Fedanzo will supervise the construction of the generators of the various fields from these calculations. Dol Kenor will correlate power and electricity to and with the fields. Westfall and I will help work out the theoretical difficulties as they arise. Pyraz Amonar, who can devise and build a machine to perform any conceivable mechanical task, will help us all in the many mechanical difficulties we shall certainly encounter. Discussion of any point is now in order."

* * * * *

Step by step and equation after equation the calculations and plans were gone over, until every detail was clear in each mind. Then the men bent to their tasks; behind them not only the extraordinarily complete facilities of that gigantic workshop which was the Sirius; but also the full power of the detachment of police—the very cream of the young manhood of the planet. Week after toilsome week the unremitting labor went on, and little by little the massive cruiser of the void became endowed with an offensive and defensive armament incredible. An armament conceived in the fertile and daring brain of a sheer genius, guided only by the knowledge that such things were already in existence somewhere; reduced to working theory by a precise, mathematical logician; translated into fields of force by the greatest known experts; powered by the indefatigable efforts of an electrical wizard; made possible by the artful mechanical devices of the greatest inventor that three worlds had ever known! Thus it was that they approached Ganymede, ready, with blanketing screens full out, save for one narrow working band, and with a keen-eyed observer at every plate. When even the hyper-critical Westfall was convinced that their preparations were as complete as they could be made with the limited information at hand, Brandon directed a beam upon the satellite and tapped off a brief message:

"stevens ganymede will arrive in about ten hours direct carrier beam toward sun we can detect it and will follow it to wherever you are sirius."

"ipv sirius," came the reply, "everything here, all x glad to see you thanks newton and stevens."

Brandon, at the controls, scanning his screens narrowly, dropped the vessel down to within a mile or two of the point of origin of Stevens' carrier beam without incident; then spoke to Westfall, at his side, with a grin.

"Nice layout the kid's got down there, Quince. It's too bad—don't look like we're going to get any action for our money a-tall. 'Sa shame, too—what's the use of wasting it, now that we've got it all made?"

"We are not done yet," cautioned Westfall, and even as he spoke an alarm bell burst into strident clamor—one of their far-flung detector screens was telling the world that it had encountered a dangerous frequency. The new ultra-lights flared instantly along the line automatically laid down by the detector, and upon the closely ruled micrometer screen of Brandon's desk there glowed in natural color the image of a globular space-ship, approaching them with terrific speed.

"Men all stationed, of course, Crown?"

"Stationed and ready." Crowninshield, phones at his ears and microphone at his lips, was staring intently into his own plate.

"Kinda think I'll do most of it from here, but you can't always tell. If they get inside my guard you all know what to do."

"All x."

Expecting another such hollow victory as the other Hexan vessel had won over the defenseless Arcturus, the small stranger flashed nearer and nearer that huge and featureless football of armor steel. Within range, she launched her flaming plane of energy, but this time that Jovian sheet of force did not encounter unprotected and non-resisting steel. Upon the outer ray-screen, flaming white into incandescent defense, the furious bolt spent itself, and in the instant of the launching of the searing blade of flame, Brandon had gone into action. Switch after switch drove home, and one after another those frightful fields of force, those products of the mightiest minds of three planets, were hurled out against the tiny Jovian sphere. Driven as they were by the millions upon millions of horsepower stored in the accumulators of the Sirius they formed a coruscating spherical shell of intolerable energy all around the enemy vessel, but even their prodigious force was held at bay by the powerful defensive screens of the smaller space-ship. But attack the Jovian could not, every resource at her command being necessary to fend off the terrific counter-attack of her intended prey, and she turned in flight. Small and agile as she was, the enormous mass of the Sirius precluded any possibility of maneuvering with the Jovian, but Brandon had no intention of maneuvering. Rapid as the motions of the stranger were and frantic as was her dodging, the terrific forces of the tractor beams of the Interplanetary Vessel held her in an unbreakable grip, and although she dragged the massive Sirius hither and thither, she could not escape.

"Hm ... m ... m," mused Brandon. "We seem to be getting nowhere fast. How much power we using, Mac, and how much have we got coming in?"

"Output eighty-five thousand kilofranks," replied MacDonald, the first assistant. "Intake forty-nine thousand."

"Not so good—can't hold out forever at that rate. Shove out the receptor screens to the limit and drive 'em. They figure a top of sixty thousand, but we ought to pick up a little extra from that blaze out there. Drive 'em full out or up to sixty-five, whichever comes first. Can't seem to crush his screens, so I guess we'll have to try something else," and a thoughtful expression came over his face as he slowly extended his hand toward another switch, with a questioning glance at Westfall.

"Better not do that yet, Norman. Use that only as a last resort, after everything else has failed."

"Yeah—I'm scared to death of trying it, and it isn't necessary yet. He must have an open slit somewhere to work through, just as we have. I'll feel around for it a while."

"Is there any way of hetrodyning the new visiray upon the exploring frequency?"

"Hm ... m.... Never thought of that—it would be nice, too.... I think we can do it, too. Watch 'em, Quince, and holler if they start anything."

He abandoned his desk and established the necessary connections between the visiray apparatus and the controls of his board. There was a fierce violet-white glare from the plate as he closed the switch, and he leaped back with his hands over his eyes, temporarily blinded.

"Wow, that's hot stuff!" he exclaimed. "It works, all x, to the queen's taste," as he donned his heavy ray-goggles and resumed his place.

After making certain that the visiray was precisely synchronized and phased with the searching frequency, he built up the power of that beam until it was using twenty thousand kilofranks. Then, by delicately manipulating the variable condensers and inductances of his sensitive shunting relay circuits, he slowly shifted that frightful rod of energy from frequency to frequency, staring into the brilliant blankness of his micrometer screen as he did so. After a few minutes of search the screen darkened somewhat, revealing the image of the Jovian globe. Brandon instantly shifted into that one channel the entire power of his attack; steadying the controls to bring the sphere of the Jovians into the sharpest possible focus, knowing that he had found the open slit and that through it there was pouring upon the enemy the full power of his terrible weapon.

In the fraction of a second before the Jovians could detect the attack and close the slit, he saw a portion of the wall of their vessel flare into white heat and literally explode outward in puffs and gouts of flaming, molten metal and of incandescent gases. But the thrust, savage as it was, had not been fatal and the enemy countered instantly. Now that the crushing force of the full-coverage attack was lessened for a moment, through another slit there poured a beam of energy equal to the Terrestrials' own—a beam of such intense power that the outer screen of the Sirius flared from red through the spectrum, to and beyond the violet, and went black in less than a second, and the inner screen had almost gone down before Brandon's lightning hands could restore the complete coverage that so effectively blanketed the forces of the enemy.

"Well, we're back to the status quo," announced Brandon, calmly. "It's a good gag they didn't have time to locate our working slit—if they had pushed that stuff through our open channel, we'd have gotten frizzled up some around the edges. As it was, we got the edge on that exchange—take it from your Uncle Dudley, Quince, that bird knows that he's been nudged!"

* * * * *

Again he searched the entire band for an opening, but could find none. The enemy had apparently retired into a tightly closed shell of energy. The small vessel no longer struggled, nor even moved, but was merely resisting passively.

"Not an open channel, not even one for him to work through—he can't wiggle. Well, that won't get him anything. We're so much bigger than he is, that we can outlast him and will get him some time, since he's bound to run out of power before we do. I don't believe he can receive anything, sealed up as he is, and he can't have accumulators enough more efficient than ours to make up the difference, can he, Quince?"

"It is quite possible. For instance, although we have never heard of any progress being made along such lines, it has been pointed out repeatedly that synthesis of a radio-active element of very high atomic weight would theoretically yield an almost perfect accumulator—one many thousands of times as efficient as ours in mass-to-energy ratio. Then, too, you realize, of course, that there is a bare possibility that intra-atomic energy may not be absolutely impossible."

"Nix on that, Quince. I'll stand for a lot, but not for that last idea! It's hard to say that anything's impossible, of course, except things made so by definition or by being contrary to observational facts, but the best work shows that intra-atomic energy is just about as impossible as anything can well be. It has been shown pretty conclusively that all ordinary matter is already in its most stable state, so that work must be done upon any ordinary atom to decompose it. Besides, if he had either radioactive accumulators or intra-atomic energy, he would have cut us up long ago. Nope, the answer is that he's probably yelled for help and is trying to hold out until it gets here," was Brandon's rejoinder.

"What can we do about it?" asked Quince.

"Don't know yet. I do know, though, that we aren't half as ready for trouble as I thought we were. There's a dozen things I want to do that I can't because we haven't got the stuff. Don't say 'I told you so,' either—I know you did! You're the champion ground-and-lofty thinker of the century. Alcantro!

"Here!"

"Round up the gang, will you, and figure me out a screen and a set of meters that will indicate an open band? We lose too much time feeling around anyhow, and we're too apt to take one on the chin while we're doing it. Also, you ought to make it so it'll shoot a jolt into the opening, while you're at it," said Brandon.

"We shall begin at once," and the massive Martian as he replied, stepped over to the calculating machine.

"Well, Quince, we can't do much to him this way—he's crawled into a hole and pulled the hole in after him. Gosh, I wish we had more stuff!"

"After all, we have everything whose necessity and practicability could have been foreseen in the light of our information. We can, of course, go further."

"You chirped it! But we can't let things ride this way or we'll get our hair singed. We'll have to decorate him with the grand slam, I guess."