"That's it, I just know it is!" Nadia declared. "Steve, as a computer, you're a blinding flash and a deafening report!"

"Yeah—missed it only about half a million kilometers or so," he replied, grinning, "and I'd fire a whole flock of I-P check stations for being four thousand off. However, I could have done worse—I could easily have forgotten all the data on it, instead of only half of it." He applied a normal negative acceleration, and Nadia heaved a profound sigh of relief as her weight returned to her and her body again became manageable by the ordinary automatic and involuntary muscles.

"Guess I am a kind of a weight-fiend at that, Steve—this is much better!" she exclaimed.

"Nobody denies that weight is more convenient at times; but you're a spacehound just the same—you'll like it after a while," he prophesied.

Stevens took careful observations upon the celestial body, altered his course sharply, then, after a measured time interval, again made careful readings.

"That's it, all x," he announced, after completing his calculations, and he reduced their negative acceleration by a third. "There—we'll be just about traveling with it when we get there," he said. "Now, little K. P. of my bosom, our supper's been on minus time for hours. What say we shake it up?"

"I check you to nineteen decimals," and the two were soon attacking the savory Ganymedean goulash which Nadia had put in the cooker many hours before.

"Should we both go to sleep, Steve, or should one of us watch it?"

"Sleep, by all means. There's no meteoric stuff out here, and we won't arrive before ten o'clock tomorrow, I-P time," and, tired out by the events of the long day, man and maid sought their beds and plunged into dreamless slumber.

While they slept, the "Forlorn Hope" drove on through the void at a terrific but constantly decreasing velocity; and far off to one side, plunging along a line making a sharp angle with their own course, there loomed larger and larger the masses which made up the nucleus of Cantrell's Comet.

Upon awakening, Stevens' first thought was for the comet, and he observed it carefully before he aroused Nadia, who hurried into the control room. Looming large in the shortened range of the plate, their objective hurtled onward in its eternal course, its enormous velocity betrayed only by the rapidity with which it sped past the incredibly brilliant background of infinitely distant stars. Apparently it was a wild jumble of separate fragments; a conglomerate, heterogeneous aggregation of rough and jagged masses varying in size from grains of sand up to enormous chunks, which upon Earth would have weighed millions of tons. Pervading the whole nucleus, a slow, indefinite movement was perceptible—a vague writhing and creeping of individual components working and slipping past and around each other as they all rushed forward in obedience to the immutable cosmic law of gravitation.

"Oh, isn't that wonderful!" Nadia breathed. "Think of actually going to visit a comet! It sort of scares me, Steve—it's so creepy and crawly looking. We're awfully close, aren't we?"

"Not so very. We'd probably have lots of time to eat breakfast. But just to be on the safe side, maybe I'd better camp here at the board, and you bring me over something to eat."

"All x, Chief!" and Stevens ate, one eye upon the screen, watching closely the ever-increasing bulk of the comet.

* * * * *

For many minutes he swung the Forlorn Hope in a wide curve approaching the mountain of metal ever and ever more nearly, then turned to the girl.

"Hold everything, Nadia—power's going off in a minute!" He shut off the beam; then, noting that they were traveling a trifle faster than the comet, he applied a small voltage to one dirigible projector. Darting the beam here and there, he so corrected their flight that they were precisely stationary in relation to the comet. He then opened his switches, and the Forlorn Hope hurtled on. Apparently motionless, it was now a part of Cantrell's Comet, traveling in a stupendous, elongated ellipse about the Master of our Solar System, the Sun.

"There, ace, who said anything about weight-fiends? I was watching you, and you never turned a hair that time."

"Why, that's right—I never even thought about it—I was so busy studying that thing out there! I suppose I've got used to it already?"

"Sure—you're one of us now. I knew you would be. Well, let's go places and do things! You'd better put on a suit, too, so you can stand in the air-lock and handle the line."

They donned the heavily insulated, heated suits, and Stevens snapped the locking plugs of the drag line into their sockets upon the helmets.

"Hear me?" he asked. "Sound-disks all x?"

"All x."

"On the radio—all x?"

"All x."

"I tested your tanks and heaters—they're all x. But you'll have to test...."

"I know the ritual by heart, Steve. It's been in every show in the country for the last year, but I didn't know you had to go through it every time you went out-of-doors! Halves, number one all x, two all x, three all x...."

"Quit it!" he snapped. "You aren't testing those valves! That check-up is no joke, guy. These suits are complicated affairs, and some parts are apt to get out of order. You see, a thing to give you fresh air at normal pressure and to keep you warm in absolute space can't be either simple or fool-proof. They've worked on them for years, but they're pretty crude yet. They're tricky, and if one goes sour on you, out in space, it's just too bad—you're lucky to get back alive. A lot of men are still out there somewhere because of the sloppy check-ups."

"'Scuse it, please—I'll be good," and the careful checking and testing of every vital part of the space-suits went on.

Satisfied at last that the armor was spaceworthy, Stevens picked up the coils of drag-line, built of a non-metallic fiber which could retain its flexibility and strength in the bitter cold of outer space, and led the girl into the air-lock.

"Heavens, Steve! It's perfectly stupendous, and grinding around worse than the wreckage of the Arcturus was when I wouldn't let you climb up it—why, I thought comets were little, and hardly massive at all!" exclaimed the girl.

"This is little, compared to any regular planet or satellite or even to the asteroids. There's only a few cubic kilometers of matter there, and, as I said before, it's a decidedly unusual comet. You know the game?"

"I've got it—and believe me, I'll yank you back here a lot faster than you can jump over there if any one of those lumps starts to fall on you! Is this drag line long enough?"

"Yes, I've got a hundred meters here, and it's only fifty meters over there to where I'm going. So long," and with a light thrust of his feet, he dove head foremost across the intervening space, a heavy pike held out ahead of him. Straight as a bullet he floated toward his objective, a jagged chunk many yards in diameter, taking the shock of his landing by sliding along the pike-handle as its head struck the mass.

Then, bracing his feet against one lump, he pushed against its neighbor, and under that steady pressure the enormous masses moved apart and kept on moving, grinding among their fellows. Over and around them Stevens sprang, always watching his line of retreat as well as that of his advance, until his exploring pike struck a lump of apparently solid metal. Hooking the fragment toward him, he thrust savagely with his weapon and was reassured—that object was not only metal, but it was metal so hard that his pike-head of space-tempered alloy steel did not make an impression upon its surface. Turning on his helmet light he swung his heavy hammer repeatedly but could not break off even a small fragment.

"Found something, Steve?" Nadia's voice came clearly in his ears.

"I'll say I have! A hunk of solid, non-magnetic metal about the size of an office desk. I can't break off any of it, so I guess we'll have to grab the whole chunk."

He hitched the end of his cable around the nugget, made sure that the loops would not slip, and then, as Nadia tightened the line, he shoved mightily.

"All x, Nadia, she's coming! Pull in my drag line as I said over there, and I'll help you land her."

Inside the Forlorn Hope the mass of metal was urged into the shop, where Stevens clamped it immovably to the steel floor, before he took off his space-suit.

"Why, it's getting covered with snow, and the whole room is getting positively cold!" Nadia exclaimed.

"Sure. Anything that comes in from space is cold, even if it's been out only a few minutes, and that hunk of stuff has been out for nobody knows how many million years. It didn't get much heat from the sun except at perihelion, you know, so it's probably somewhere around minus two hundred and sixty degrees now. I'll have to throw a heater on it for half an hour before we can touch it. And since this is more or less new stuff to you, I'll caution you—don't try to touch anything that has just come in. That hammer or pike would freeze your hand instantly, even though they've been out only a little while. Before you touch anything, blow on it, like this, see? If your breath freezes solid on it, like that, don't touch it—it's cold."

* * * * *

Under the infra-beams of the heater, the mass of the metal was brought to room temperature and Stevens attacked it with his machine tools. Bit by bit the stubborn material was torn from the lump. Through heavy goggles he watched the incandescent mass in a refractory crucible, in the heart of the induction furnace.

"What do you think you've got—what you want?"

"I don't know. It wasn't iron—it wouldn't hold a magnet. It's royal metal of some kind, I think. Base metals mostly melt at around fifteen hundred, and that crucible is still dry as a bone at better than seventeen."

"How are you going to separate out the tantalum and the others you want from the ones that you don't want?"

"I'm afraid that I'm not going to, very well," replied Stevens, with a wry grimace. "What I don't know about metallurgy would fill a library, and I'm probably the world's worst chemist. However, by a series of successive liquations, I hope to separate out fractions that I can use. Platinum melts somewhere around seventeen-fifty, tantalum about twenty-nine hundred, and tungsten not until 'way up around thirty-three, or four hundred—and that, by the way, means lots of grief. Of course, each fraction will probably be an alloy of one kind or another, but I think maybe I'll be able to make them do."

"But mayn't that whole chunk be a pure metal?"

"It's conceivable, but not probable. There, she's beginning to separate at just below eighteen hundred! Platinum group coming out now, I think—platinum, rhodium, iridium, and that gang, you know. While I'm doing this, you might be getting those five coils into exact resonance, if you want to."

"Sure I want to," and Nadia made her way across to the short-wave oscillator and set to work.

After an hour or so, bent over her delicate task, she began to twitch uneasily, then shrugged her shoulders impatiently.

"What's the idea of staring at me so?" she broke out suddenly. "How do you expect me to tune these things up if you...." She stopped abruptly, mouth open in amazement, as she turned toward Stevens. He had not been looking at her, but he turned a surprised face from his own task at the sound of her voice. "Excuse me, please, Steve. I don't know what's the matter with me—must be getting jumpy, I guess."

"I wish that was all, but it isn't!" Face suddenly grim and hard, Stevens leaped to the communicator plate and shot the beam out into space. "There's an answer, but that isn't it. You're a fine-tuned instrument yourself, ace, and you've detected something.... I thought so! There's the answer—the guy that was looking at you!"

Plainly there was revealed upon the plate a small, spherical space-ship, very like the one that had attacked and destroyed the Arcturus. After Nadia had taken one glance at it, Stevens shut off the power and leaped out into the shop. He closed all the bulkhead doors and air-break openings, then closed and secured the massive insulating door of the lifeboat in which they had made their headquarters. Then, after they had again put on the space-suits they had taken off such a short time before, he extinguished all the lights and hooded the communicator screen before he ventured again to glance out into the void.

"If I had a brain in my head, instead of the pint of bean soup I've got up there, we'd have worn these when they cut up the Arcturus, and saved us a lot of mental wear and tear," he remarked. "They were right there in the lockers all the time, and I knew it!"

"Well, we got away, anyway. You couldn't be expected to think of everything at once. We didn't have much time, you know."

"No, but I should have thought of anything as obvious as that, anyway. Wonder how they found us? Did they detect us, or did they come out to this comet after metal, same as we did, and find us accidentally? However, it all works out the same—they're apparently out to get us. I'm afraid this is going to be a whole lot like a rabbit fighting back at a man with a gun; but we'll sure try to nibble us off a lunch while they're getting a square meal ... here they come!"

The enemy sphere launched its flaming plane of force, and the Forlorn Hope shuddered in every plate and member as its apex was severed cleanly under the impact. Instantly Stevens hurled his only weapons. Flaming ultra-violet and dully glowing infra-red, the twin beams lashed out; but their utmost force was of slight moment to the enormous power driving the enemy screens. Two circular spots of cherry red in space were the only results of Stevens' attack, and the next fierce cut sheared away the two projectors and, incidentally, a full half of the fifty-inch armor of the leading edge.

"Then we're checking out now?" Nadia asked quietly, as the man's hands dropped from his useless controls. "I'm sorrier than I can say, lover. But at least, I'm glad that I can go out with you," and her glorious eyes were shining with unshed tears.

"Maybe, but snap out of it, girl—our hearts are still beating! We're not dead yet, and maybe we won't be. Perhaps they want to capture us alive, as they did before; if so, we may be able to hide out on them somewhere and pull off another escape. Things don't look very bright, I know, but we're not checking out until our numbers are actually run up!"

He hooked a hand under her belt as the shocks came closer, and stood tense and ready. The lancing plane cut through one end of their control room, and Stevens leaped with his companion toward the new-made opening; while the air shrieked outward into space and their suits bulged suddenly with the abrupt increase in pressure differential. While they were in midflight, the frightful blade of destruction cleaved its way through the control board and through the spot upon which they had been standing a moment before. As they passed the severed edge, en route into open spare, Stevens seized a metal brace and clung there, every nerve taut.

"Something funny here, Nadia," he said after a little, in a low tone. "They should have made one more cut, to make us absolutely blind and helpless. As it is, they've clipped off all our projectors, so we can't move, but I think we've got the whole control compartment of number two lifeboat untouched. If so, we can look around, anyway. Let's go!"

Floating without effort from fragment to fragment, they made their way toward the section of their cruiser as yet undamaged. They found an airlock in working order, and were soon in the second lifeboat, where Stevens hastily turned on a communicator and peered out into space.

"There they are! There's another stranger out there, too. They're fighting with her, now—that's probably why they didn't polish us off." Steel-braced, clumsy helmets touching, the two Terrestrials stared spell-bound into the plate; watching while the insensately vicious intelligences within the sphere brought its every force to bear upon another and larger sphere which was now so close as to be plainly visible. Like a gigantic drop of quicksilver this second globe appeared—its smooth and highly-polished surface one enormous, perfect, spherical mirror. Watching tensely, they saw flash out that frightful plane of seething energy, with the effects of which they were all too familiar, and saw it strike full upon the dazzling ball.

"This is awful, ace!" Stevens groaned. "They haven't got ray-screens, either, and without them they don't stand a chance. No possible substance can stand up under that beam. When they get done and turn back to us, we'll have to dive back to where we were."

* * * * *

But that brilliant mirror was not as vulnerable as Stevens had supposed. The plane of force struck and clung, but could not penetrate it. Broken up into myriads of scintillating crystals of light, intersecting, multi-colored rays, and cascading flares of sparkling energy, the beam was reflected, thrown back, hurled away on all sides into space in coruscating, blinding torrents. And neither was the monster globe inoffensive. The straining watchers saw a port open suddenly, emit a flame-erupting something, and close as rapidly as it had opened. That something was a projectile, its propelling rockets fiercely aflame; as smoothly brilliant as its mother-ship and seemingly as impervious to the lethal beams of the common foe. Detected almost instantly as it was, it received the full power of the savage attack. The hitherto irresistible plane of force beat upon it; ultra-violet, infra-red, and heat rays enveloped it; there were hurled against it all the forces known to the scientific minds within that fiendishly destructive sphere.

Finally, only a scant few hundreds of yards from its goal, the protective mirror was punctured and the freight of high explosive let go, with a silent, but nevertheless terrific, detonation. But now another torpedo was on its way, and another, and another; boring on ruthlessly toward the smaller sphere. Fighting simultaneously three torpedos and the giant globe, the enemy began dodging, darting hither and thither with a stupendous acceleration; but the tiny pursuers could not be shaken off. At every dodge and turn, steering rockets burst into furious activity and the projectiles rushed ever nearer. Knowing that she had at last encountered a superior force, the sphere turned in mad flight; but, prodigious as was her acceleration, the torpedoes were faster and all three of them struck her at once. There ensued an explosion veritably space-racking in its intensity; a flash of incandescent brilliance that seemed to fill all space, subsiding into a vast volume of tenuous gas which, feebly glowing, flowed about and attached itself to Cantrell's Comet. And in the space where had been the enemy sphere, there was nothing.

A slow-creeping pale blue rod of tangible force reached out from the great sphere, touched the wreckage of the Forlorn Hope, and pulled; gently, but with enormous power.

"Tractor beams again!" exclaimed Stevens, still at the plate. "Everybody's got 'em but us, it seems."

"And we can't fight a bit any more, can we?"

"Not a chance—bows and arrows wouldn't do us much good. However, we may not need 'em. Since they fought that other crew, and haven't blown us up, they aren't active enemies of ours, and may be friendly. I haven't any idea who or what they are, since even our communicator ray can't get through that mirror, but it looks as though our best bet is to act peaceable and see if we can't talk to them in some way. Right?"

"Right." They stepped out into the airlock, from which they saw that the great sphere had halted only a few yards from them, and that an indistinct figure stood in an open door, waving to them an unmistakable invitation to enter the strange vessel.

"Shall we, Steve?"

"Might as well. They've got us foul, and can take us if they want us. Anyway, we'll need at least a week to fix us up any kind of driving power, so we can't run—and we probably couldn't get away from those folks if we had all our power. They haven't blown us up, and they could have done it easily enough. Besides, they act friendly, so we'd better meet them half way. Dive!"

Floating toward the open doorway, they were met by another rod of force, brought gently into the airlock, and supported upright beside the being who had invited them to visit him. Apparently an empty space-suit stood there; a peculiarly-fitted suit of some partially transparent, flexible, glass-like material; towering fully a foot over the head of the tall Terrestrial. Closer inspection, however, revealed that there was something inside that suit—a shadowy, weirdly-transparent being, staring at them with large, black eyes. The door clanged shut behind them; they heard the faint hiss of inrushing air, and the inner door opened; but their enveloping suits remained stretched almost as tightly as ever. They felt the floor lurch beneath their feet, and a little weight was granted them as the space-ship got under way. Stevens waved his arms vigorously at the stranger, pointing backward toward where he supposed their own craft to be. The latter waved an arm reassuringly, pressed a contact, and a section of the wall suddenly became transparent. Through it Stevens saw with satisfaction that the Forlorn Hope was not being abandoned; in the grip of powerful tractor beams, every fragment of the wreckage was following close behind them in their flight through space.

* * * * *

Stevens and Nadia followed their guide along a corridor, through several doors, and into a large room, which at first glance seemed empty, but in which several of the peculiarly transparent people of the craft were lying about upon cushions. They were undoubtedly human—but what humans! Tall and reedy they were, with enormous barrel chests, topped by heads which, though really large, appeared insignificant because of the prodigious chests and because of the huge, sail-like, flapping ears. Their skins were a strikingly, livid, pale blue, absolutely devoid of hair; and their lidless eyes, without a sign of iris, were chillingly horrible in their stark contrast of enormous, glaring black pupil and ghastly, transparent blue eyeball.

As the two Terrestrials entered the room, the beings struggled to their feet and hurried laboriously away. Soon one of them returned, dressed in an insulating suit, and carrying three sets of head harnesses, connected by multiplex cables to a large box which he placed upon the floor. He handed the headsets to the first officer, who in turn placed two of them at the feet of the Terrestrials, indicating to them that they were to follow his example in placing them upon their heads, outside the helmets. They did so, and even through the almost perfect insulation, and in spite of the powerful heaters of their suits, they felt a touch of frightful cold. The stranger turned a dial, and the two wanderers from Earth were instantly in full mental communication with Barkovis, the commander of a space-ship of Titan, the sixth satellite of Saturn!

"Well, I'll be ... say, what is this, anyway?" Steve exclaimed involuntarily, and Nadia smiled as Barkovis answered with a thought, clearer than any spoken words.

"It is a thought-exchanger. I do not know its fundamental mechanism, since we did not invent it and since I have had little time to study it. The apparatus, practically as you see it here, was discovered but a short time ago, in a small, rocket-propelled space-ship which we found some distance outside of the orbit of Jupiter. Its source of power had been destroyed by the cold of outer space, but re-powering it was, of course, a small matter. The crew of the vessel were all dead. They were, however, of human stock, and of a type adapted for life upon a satellite. I deduce, from your compact structure, your enormous atmospheric pressure, and your, to us, unbelievably high body temperature, that you must be planet-dwellers. I suppose that you are natives of Jupiter?"

"Not quite." Stevens had in a measure recovered from his stunned surprise. "We are from Tellus, the third planet," and he revealed rapidly the events leading up to their present situation, concluding: "The people in the other sphere were, we believe, natives of Jupiter or of one of the satellites. We know nothing of them, since we could not look through their screens. You rescued us from them; do you not know them?"

"No. Our visirays also were stopped by their screens of force—screens entirely foreign to our science. This is the first time that any vessel from our Saturnian system has ever succeeded in reaching the neighborhood of Jupiter. We came in peace, but they attacked us at sight and we were obliged to destroy them. Now we must hurry back to Titan, for two reasons. First, because we are already at the extreme limit of our power range and Jupiter is getting further and further away from Saturn. Second because our mirrors, which we had thought perfect reflectors of all frequencies possible of generation, are not perfect. Enough of those forces came through the mirrors to volatilize half our crew, and in a few minutes more none of us would have been left alive. Why, in some places our very atmosphere became almost hot enough to melt water! If another of those vessels should attack us, in all probability we should all be lost. Therefore we are leaving as rapidly as is possible."

"You are taking the pieces of our ship along—we do not want to encumber you."

"It is no encumbrance, since we have ample supplies of power. In fact, we are now employing the highest acceleration we Titanians can endure for any length of time."

Stevens pondered long, forgetting that his thoughts were plain as print to the Titanian commander. Thank Heaven these strangers had sense enough to be friendly—all intelligent races should be friends, for mutual advancement. But it was a mighty long stretch to Saturn and this acceleration wasn't so much. How long would it take to get there? Could they get back? Wouldn't they save time by casting themselves adrift, making the repairs most urgently needed, and going back to Ganymede under their own power? But would they have enough power left in the wreck to get even that far? And how about the big tube? He was interrupted by an insistent thought from Barkovis.

"You will save time, Stevens, by coming with us to Titan. There we shall aid you in repairing your vessel and in completing your transmitting tube, in which we shall be deeply interested. Our power plants shall supply you with energy for your return journey until you are close enough to Jupiter to recover your own beam. You are tired. I would suggest that you rest—that you sleep long and peacefully."

"You seem to be handling the Forlorn Hope without any trouble—the pieces aren't grinding at all. We'd better live there, hadn't we?"

"Yes that would be best, for all of us. You could not live a minute here without your suits; and, efficiently insulated as those suits are, yet your incandescent body temperature makes our rooms unbearably hot—so hot that any of us must wear a space-suit while in the same room with you, to avoid being burned to death."

"The incandescently hot" Terrestrials were wafted into the open airlock of their lifeboat upon a wand of force, and soon had prepared a long overdue supper, over which Stevens cast his infectious, boyish grin at Nadia.

"Sweetheart, you are undoubtedly a 'warm number,' and you have often remarked that I 'burn you up.' Nevertheless I think that we were both considerably surprised to discover that we are both hot enough actually to consume persons unfortunate enough to be confined in the same room with us!"

"You're funny, Steve—like a crutch," she rebuked him, but smiled back, an elusive dimple playing in one lovely brown cheek. "Looking right through anybody is too ghastly for words, but I think they're perfectly all x, anyway, in spite of their being so hideous and so cold-blooded!"



CHAPTER VI

A Frigid Civilization

"Hi, Percival Van Schravendyck Stevens!" Nadia strode purposely into Stevens' room and seized him by the shoulder. "Are you going to sleep all the way to Saturn? You answered me when I pounded on the partition with a hammer, but I don't believe that you woke up at all. Get up, you—breakfast will be all spoiled directly!"

"Huh?" Stevens opened one sluggish eye; then, as the full force of the insult penetrated his consciousness, he came wide awake. "Lay off those names, ace, or you'll find yourself walking back home!" he threatened.

"All x by me!" she retorted. "I might as well go home if you're going to sleep all the time!" and she widened her expressive eyes at him impishly as she danced blithely back into the control room. As she went out she slammed his door with a resounding clang, and Stevens pried himself out of his bunk one joint at a time, dressed, and made himself presentable.

"Gosh!" he yawned mightily as he joined the girl at breakfast. "I don't know when I've had such a gorgeous sleep. How do you get by on so little?"

"I don't. I sleep a lot, but I do it every night, instead of working for four days and nights on end and then trying to make up all those four nights' sleep at once. I'm going to break you of that, too, Steve, if it's the last thing I ever do."

"There might be certain advantages in it, at that," he conceded, "but sometimes you've got to do work when it's got to be done, instead of just between sleeps. However, I'll try to do better. Certainly it is a wonderful relief to get out of that mess, isn't it?"

"I'll say it is! But I wish that those folks were more like people. They're nice, I think, really, but they're so ... so ... well, so ghastly that it simply gives me the blue shivers just to look at one of them!"

"They're pretty gruesome, no fooling," he agreed, "but you get used to things like that. I just about threw a fit the first time I ever saw a Martian, and the Venerians are even worse in some ways—they're so clammy and dead-looking—but now I've got real friends on both planets. One thing, though, gives me the pip. I read a story a while ago—the latest best-seller thing of Thornton's named 'Interstellar Slush' or some such tr...."

"Cleophora—An Interstellar Romance," she corrected him. "I thought it was wonderful!"

"I didn't. It's fundamentally unsound. Look at our nearest neighbors, who probably came from the same original stock we did. A Tellurian can admire, respect, or like a Venerian, yes. But for loving one of them—wow! Beauty is purely relative, you know. For instance, I think that you are the most perfectly beautiful thing I ever saw; but no Venerian would think so. Far from it. Any Martian that hadn't seen many of us would have to go rest his eyes after taking one good look at you. Considering what love means, it doesn't stand to reason that any Tellurian woman could possibly fall in love with any man not of her own breed. Any writer is wrong who indulges in interplanetary love affairs and mad passions. They simply don't exist. They can't exist—they're against all human instincts."

"Inter-planetary—in this solar system—yes. But the Dacrovos were just like us, only nicer."

"That's what gives me the pip. If our own cousins of the same solar system are so repulsive to us, how would we be affected by entirely alien forms of intelligence?"

"May be you're right, of course—but you may be wrong, too," she insisted. "The Universe is big enough, so that people like the Dacrovos may possibly exist in it somewhere. May be the Big Three will discover a means of interstellar travel—then I'll get to see them myself, perhaps."

"Yes, and if we do, and if you ever see any such people, I'll bet that the sight of them will make your hair curl right up into a ball, too! But about Barkovis—remember how diplomatic the thoughts were that he sent us? He described our structure as being 'compact,' but I got the undertone of his real thoughts, as well. Didn't you?"

"Yes, now that you mention it, I did. He really thought that we were white-hot, under-sized, overpowered, warty, hairy, hideously opaque and generally repulsive little monstrosities—thoroughly unpleasant and distasteful. But he was friendly, just the same. Heavens, Steve! Do you suppose that he read our real thoughts, too?"

"Sure he did; but he is intelligent enough to make allowances, the same as we are doing. He isn't any more insulted than we are. He knows that such feelings are ingrained and cannot be changed."

* * * * *

Breakfast over, they experienced a new sensation. For the first time in months they had nothing to do! Used as they were to being surrounded by pressing tasks, they enjoyed their holiday immensely for a few hours. Sitting idly at the communicator plate, they scanned the sparkling heavens with keen interest. Beneath them Jupiter was a brilliant crescent not far from the sun in appearance, which latter had already grown perceptibly smaller and less bright. Above them, and to their right, Saturn shone refulgently, his spectacular rings plainly visible. All about them were the glories of the firmament, which never fail to awe the most seasoned observer. But idleness soon became irksome to those two active spirits, and Stevens prowled restlessly about their narrow quarters.

"I'm going to go to work before I go dippy," he soon declared. "They've got lots of power, and we can rig up a transmitter unit to send it over here to our receptor. Then I can start welding the old Hope together without waiting until we get to Titan to start it. Think I'll signal Barkovis to come over, and see what he thinks about it."

The Titanian commander approved the idea, and the transmitting field was quickly installed. Nadia insisted that she, too, needed to work, and that she was altogether too good a mechanic to waste; therefore the two again labored mightily together, day after day. But the girl limited rigidly their hours of work to those of the working day; and evening after evening Barkovis visited with them for hours. Dressed in his heavy space-suit and supported by a tractor beam well out of range of what seemed to him terrific heat radiated by the bodies of the Terrestrials, he floated along unconcernedly; while over the multiplex cable of the thought-exchanger he conversed with the man and woman seated just inside the open outer door of their air-lock. The Titanian's appetite for information was insatiable—particularly did he relish everything pertaining to the earth and to the other inner planets, forever barred to him and to his kind. In return Stevens and Nadia came gradually to know the story of the humanity of Titan.

"I am glad beyond measure to have known you," Barkovis mused, one night. "Your existence proves that there is truth in mythology, as some of us have always believed. Your visit to Titan will create a furor in scientific circles, for you are impossibility incarnate—personifications of the preposterous. In you, wildest fancy had become commonplace. According to many of our scientists, it is utterly impossible for you to exist. Yet you say, and it must be, that there are millions upon millions of similar beings. Think of it! Venerians, Tellurians, Martians, the satellite dwellers of the lost space-ship, and us—so similar mentally, yet physically how different!"

"But where does the mythology come in?" thought Nadia.

"We have unthinkably ancient legends which say that once Titan was extremely hot, and that our remote ancestors were beings of fire, in whose veins ran molten water instead of blood. Since our recorded history goes back some tens of thousands of Saturnian years, and since in that long period there has been no measurable change in us, few of us have believed in the legends at all. They have been thought the surviving figments of a barbarous, prehistoric worship of the sun. However, such a condition is not in conflict with the known facts of cosmogony, and since there actually exists such a humanity as yours—a humanity whose bodily tissues actually are composed largely of molten water—those ancient legends must indeed have been based upon truth.

"What an evolution! Century after century of slowly decreasing temperature—one continuous struggle to adapt the physique to a constantly changing environment. First they must have tried to maintain their high temperature by covering and heating their cities.—Then, as vegetation died, they must have bred into their plants the ability to use as sap purely chemical liquids, such as our present natural fluids—which also may have been partly synthetic then—instead of the molten water to which they had been accustomed. They must have modified similarly the outer atmosphere; must have made it more reactive, to compensate for the lowered temperature at which metabolism must take place. As Titan grew colder and colder they probably dug their cities deeper and ever deeper; until humanity came finally to realize that it must itself change completely or perish utterly.

"Then we may picture them as aiding evolution in changing their body chemistry. For thousands, and thousands of years there must have gone on the gradual adaptation of blood stream and tissue to more and more volatile liquids, and to lower and still lower temperatures. This must have continued until Titan arrived at the condition which has now obtained for ages—a condition of thermal equilibrium with space upon one hand and upon the other the sun, which changes appreciably only in millions upon millions of years. In equilibrium at last—with our bodily and atmospheric temperatures finally constant at their present values, which seem as low to you as yours appear high to us. Truly, an evolution astounding to contemplate!"

"But how about power?" asked Stevens. "You seem to have all you want, and yet it doesn't stand to reason that there could be very much generated upon a satellite so old and so cold."

"You are right. For ages there has been but little power produced upon Titan. Many cycles ago, however, our scientists had developed rocket-driven space-ships, with which they explored our neighboring satellites, and even Saturn itself. It is from power plants upon Saturn that we draw energy. Their construction was difficult in the extreme, since the pioneers had to work in braces because of the enormous force of gravity. Then, too, they had to be protected from the overwhelming pressure and poisonous qualities of the air, and insulated from a temperature far above the melting point of water. In such awful heat, of course, our customary building material, water, could not be employed...."

"But all our instruments have indicated that Saturn is cold!" Stevens interrupted.

"Its surface temperature, as read from afar, would be low," conceded Barkovis, "but the actual surface of the planet is extremely hot, and is highly volcanic. Practically none of its heat is radiated because of the great density and depth of its atmosphere, which extends for many hundreds of your kilometers. It required many thousands of lives and many years of time to build and install those automatic power plants, but once they were in operation, we were assured of power for many tens of thousands of years to come."

"Our system of power transmission is more or less like yours, but we haven't anything like your range. Suppose you'd be willing to teach me the computation of your fields?"

"Yes, we shall be glad to give you the formulae. Being an older race, it is perhaps natural that we should have developed certain refinements as yet unknown to you. But I am, I perceived, detaining you from your time of rest—goodbye," and Barkovis was wafted back toward his mirrored globe.

"What do you make of this chemical solution blood of theirs, Steve?" asked Nadia, watching the placidly floating form of the Titanian captain.

"Not much. I may have mentioned before that there are one or two, or perhaps even three men who are better chemists than I am. I gathered that it is something like a polyhydric alcohol and something like a substituted hydrocarbon, and yet different from either in that it contains flourin in loose combination. I think it is something that our Tellurian chemists haven't got yet; but they've got so many organic compounds now that they may have synthesized it, at that. You see, Titan's atmosphere isn't nearly as dense as ours, but what there is of it is pure dynamite. Ours is a little oxygen, mixed with a lot of inert ingredients. Theirs is oxygen, heavily laced with flourin. It's reactive, no fooling! However, something pretty violent must be necessary to carry on body reactions at such a temperature as theirs."

"Probably; but I know even less about that kind of thing than you do. Funny, isn't it, the way he thinks 'water' when he means ice, and always thinks of our real water as being molten?"

"Reasonable enough when you think about it. Temperature differences are logarithmic, you know, not arithmetic—the effective difference between his body temperature and ours is perhaps even greater than that between ours and that of melted iron. We never think of iron as being a liquid, you know."

"That's right, too. Well, good night, Steve dear."

"'Bye, little queen of space—see you at breakfast," and the Forlorn Hope became dark and silent.

* * * * *

Day after day the brilliant sphere flew toward distant Saturn, with the wreckage of the Forlorn Hope in tow. Piece by piece that wreckage was brought together and held in place by the Titanian tractors; and slowly but steadily, under Stevens' terrific welding projector, the stubborn steel flowed together, once more to become a seamless, spaceworthy structure. And Nadia, the electrician, followed close behind the welder. Wielding torch, pliers and spanner with practised hand, she repaired or cut out of circuit the damaged accumulator cells and reunited the ends of each severed power lead. Understanding Nadia's work thoroughly, the Titanians were not particularly interested in it; but whenever Stevens made his way along an outside seam, he had a large and thrillingly horrified gallery. Everyone who could possibly secure permission to leave the sphere did so, each upon his own pencil of force, and went over to watch the welder. They did not come close to him—to venture within fifty feet of that slow moving spot of scintillating brilliance, even in a space-suit, meant death—but, poised around him in space, they watched with shuddering, incredulous amazement, the monstrous human being in whose veins ran molten water instead of blood; whose body was already so fiercely hot that it could exist unharmed while working practically without protection, upon liquefied metal!

Finally the welding was done. The insulating space was evacuated and held its vacuum—outer and inner shells were bottle-tight. The two mechanics heaved deep sighs of relief as they discarded their cumbersome armor and began to repair what few of their machine tools had been damaged by the slashing plane of force which had so neatly sliced the Forlorn Hope into sections.

"Say, big fellow, you're the guy that slings the ink, ain't you?" Nadia extinguished her torch and swaggered up to Stevens, hands on hips, her walk an exaggerated roll. "Write me out a long walk. This job's all played out, so I think I'll get me a good job on Titan. I said give me my time, you big stiff!"

"You didn't say nothing!" growled Stevens in his deepest bass, playing up to her lead as he always did. "Bounce back, cub, you've struck a rubber fence! You signed on for duration and you'll stick—see?"

Arm in arm they went over to the nearest communicator plate. Flipping the switch, Stevens turned the dial and Titan shone upon the screen; so close, that it no longer resembled a moon, but was a world toward which they were falling with an immense velocity.

"Not close enough to make out much detail yet—let's take another look at Saturn," and Stevens projected the visiray beam out toward the mighty planet. It was now an enormous full moon, almost five degrees in apparent diameter,[1] its visible surface an expanse of what they knew to be billowing cloud, shining brilliantly white in the pale sunlight, broken only by a dark equatorial band.

[Footnote 1: The moon subtends an angle of about one-half of a degree.]

"Those rings were such a gorgeous spectacle a little while ago!" Nadia mourned. "It's a shame that Titan has to be right in their plane, isn't it? Think of living this close to one of the most wonderful sights in the Solar System, and never being able to see it. Think they know what they're missing, Steve?"

"We'll have to ask Barkovis," Stevens replied. He swung the communicator beam back toward Titan, and Nadia shuddered.

"Oh, it's hideous!" she exclaimed. "I thought that it would improve as we got closer, but the plainer we can see it, the worse it gets. Just to think of human beings, even such cold-blooded ones as those over there, living upon such a horrible moon and liking it, gives mi the blue shivers!"

"It's pretty bleak, no fooling," he admitted, and peered through the eyepiece of the visiray telescope, studying minutely the forbidding surface of the satellite they were so rapidly approaching.

Larger and larger it loomed, a cratered, jagged globe of desolation indescribable; of sheer, bitter cold incarnate and palpable; of stark, sharp contrasts. Gigantic craters, in whose yawning depths no spark of warmth had been generated for countless cycles of time, were surrounded by vast plains eroded to the dead level of a windless sea. Every lofty object cast a sharply outlined shade of impenetrable blackness, beside which the weak light of the sun became a dazzling glare. The ground was either a brilliant white or an intense black, unrelieved by half-tones.

"I can't hand it much, either, Nadia, but it's all in the way you've been brought up, you know. This is home to them, and just to look at Tellus would give them the pip. Ha! Here's something you'll like, even if it does look so cold that it makes me feel like hugging a couple of heater coils. It's Barkovis' city the one we're heading for, I think. It's close enough now so that we can get it on the plate," and he set the communicator beam upon the metropolis of Titan.

"Why, I don't see a thing, Steve—where and what is it?" They were dropping vertically downward toward the center of a vast plain of white, featureless and desolate; and Nadia stared in disappointment.

"You'll see directly—it's too good to spoil by telling you what to look for or wh...."

"Oh, there it is!" she cried. "It is beautiful, Steve, but how frightfully, utterly cold!"

* * * * *

A flash of prismatic color had caught the girl's eye, and, one transparent structure thus revealed to her sight, there had burst into view a city of crystal. Low buildings of hexagonal shape, arranged in irregularly variant hexagonal patterns, extended mile upon mile. From the roofs of the structures lacy spires soared heavenward; inter-connected by long, slim cantilever bridges whose prodigious spans seemed out of all proportion to the gossamer delicacy of their construction. Buildings, spires, and bridges formed fantastic geometrical designs, at which Nadia exclaimed in delight.

"I've just thought of what that reminds me of—it's snowflakes!"

"Sure—I knew it was something familiar. Snowflakes—no two are ever exactly alike, and yet every one is symmetrical and hexagonal. We're going to land on the public square—see the crowds? Let's put on our suits and go out."

The Forlorn Hope lay in a hexagonal park, and near it the Titanian globe had also come to rest. All about the little plot towered the glittering buildings of crystal, and in its center played a fountain; a series of clear and sparkling cascades of liquid jewels. Under foot there spread a thick, soft carpet of whitely brilliant vegetation. Throngs of the grotesque citizens of Titania were massed to greet the space-ships; throngs clustering close about the globular vessel, but maintaining a respectful distance from the fiercely radiant Terrestrial wedge. All were shouting greetings and congratulations—shouts which Stevens found as intelligible as his own native tongue.

"Why, I can understand every word they say, Steve!" Nadia exclaimed, in surprise. "How come, do you suppose?"

"I can, too. Don't know—must be from using that thought telephone of theirs so much, I guess. Here comes Barkovis—I'll ask him."

The Titanian commander had been in earnest conversation with a group of fellow-creatures and was now walking toward the Terrestrials, carrying the multiple headsets. Placing them upon the white sward, he backed away, motioning the two visitors to pick them up.

"It may not be necessary, Barkovis," Stevens said, slowly and clearly. "We do not know why, but we can understand what your people are saying, and it may be that you can now understand us."

"Oh, yes, I can understand your English perfectly. A surprising development, but perhaps, after all, one that should have been expected, from the very nature of the device we have been using. I wanted to tell you that I have just received grave news, which makes it impossible for us to help you immediately, as I promised. While we were gone, one of our two power-plants upon Saturn failed. In consequence, Titan's power has been cut to a minimum, since maintaining our beam at that great distance required a large fraction of the output of the other plant. Because of this lack, the Sedlor walls were weakened to such a point that in spite of the Guardian's assurances, I think trouble is inevitable. At all events, it is of the utmost importance that we begin repairing the damaged unit, for that is to be a task indeed."

"Yes, it will take time," agreed Stevens, remembering what the Titanian captain had told him concerning the construction of those plants—generators which had been in continuous and automatic operation for thousands of Saturnian years.

"It will take more than time—it will take lives," replied Barkovis, gravely. "Scores, perhaps hundreds, of us will never again breathe the clear, pure air of Titan. In spite of all precaution and all possible bracing and insulation, man after man after man will be crushed by his own weight, volatilized by the awful heat, poisoned by the foul atmosphere, or will burst into unthinkable flames at the touch of some flying spark from the inconceivably hot metals with which we shall have to work. A horrible fate, but we shall not lack for volunteers."

"Sure not; and of course you yourself would go. And I never thought of the effect a spark would have on you—your tissues would probably be wildly inflammable. But say, I just had a thought. Just how hot is the air at those plants and just what is the actual pressure?"

"According to the records, the temperature is some forty of your centigrade degrees above the melting-point of water, and the pressure is not far short of two of your meters of mercury. I find it almost impossible to think of mercury as a liquid, however."

"You find it impossible, since you use it as a metal, for wires in coils and so on. But plus forty, while pretty warm, isn't impossible, by any means; and we could stand double our air pressure for quite a while. Both my partner and I are pretty fair mechanics and we've got quite a line of machine tools, such as you could not possibly have here. We'll give it a whirl, since we owe you something already. Lead us to it, ace—but wait a minute! We can't see through the fog, so couldn't find the plants, and probably your wiring diagrams would explode if I touched them."

"I never thought of your helping us," mused Barkovis. "The idea of any living being existing in that inferno has always been unthinkable, but the difficulties you mention are slight. We have already built in our vessel communicators similar to yours, and radio sets. With these we can guide you and explain the plants to you as you work, and our tractor beams will be of assistance to you in moving heavy objects, even at such distances from the surface as we Titanians shall have to maintain. If you will set out a flask of your atmosphere, we will analyze it, for the thought has come to me that perhaps, being planet-dwellers yourselves, the air of Saturn might not be as poisonous to you as it is to us."

"That's a thought, too," and, the news broadcast, it was not long until the two ships leaped into the air, to the accompaniment of the cheers and plaudits of a watching multitude.

* * * * *

In a wide curve they sped toward Saturn. Passing so close to the enormous rings that the individual meteoric fragments could almost be seen with the unaided eye, they flashed on and on, slowing down long before they approached the upper surface of the envelope of cloud. The spherical space-ship stopped and Stevens, staring into his useless screen, drove the Forlorn Hope downward mile after mile, solely under Barkovis' direction, changing course and power from time to time as the Titanian's voice came from the speaker at his elbow. Slower and slower became the descent, until finally, almost upon the broad, flat roof of the power-plant, Stevens saw it in his plate. Breathing deeply in relief, he dropped quickly down upon a flat pavement, neutralized his controls, and turned to Nadia.

"Well, old golf-shootist, we're here at last—now we'll go out and see what's gone screwy with the works. Remember that gravity is about double normal here, and conduct yourself accordingly."

"But it's supposed to be only about nine-tenths," she objected.

"That's at the outer surface of the atmosphere," he replied. "And it's some atmosphere—not like the thin layer we've got on Tellus."

They went into the airlock, and Stevens admitted air until their suits began to collapse. Then, face-plate valves cracked, he sniffed cautiously, finally opening his helmet wide. Nadia followed suit and the man laughed as she wrinkled her nose in disgust as two faint, but unmistakable odors smote her olfactory nerves.

"I never cared particularly for hydrogen sulphide and sulphur dioxide, either," he assured her, "but they aren't strong enough to hurt us in the short time we'll be here. Those Titanian chemists know their stuff, though."

He opened the outer valves slowly, then opened the door and they stepped down upon the smooth, solid floor, which Stevens examined carefully.

"I thought so, from his story. Solid platinum! This whole planet is built of platinum, iridium, and noble alloys—the only substances known that will literally last forever. Believe me, ace of my bosom, I don't wonder that it cost them lives to build it—with their conditions, I don't see how they ever got it built at all."

Before them rose an immense, flat-topped cone of metal, upon the top of which was situated the power plant. Twelve massive pillars supported a flat roof, but permitted the air to circulate freely throughout the one great room which housed the machinery. They climbed a flight of stairs, passed between two pillars, and stared about them. There was no noise, no motion—there was nothing that could move. Twelve enormous masses of metallic checkerwork, covered with wide cooling fins, almost filled the vast hall. From the center of each mass great leads extended out into a clear space in the middle of the room, there uniting in mid-air to form one enormous bus-bar. This bar, thicker than a man's body, had originally curved upward to the base of an immense parabolic structure of latticed bars. Now, however, it was broken in midspan and the two ends bent toward the floor. Above their heads, a jagged hole gaped in the heavy metal of the roof, and a similar hole had been torn in the floor. The bar had been broken and these holes had been made by some heavy body, probably a meteorite, falling with terrific velocity.

"This is it, all right," Stevens spoke to distant Barkovis. "Sure there's nothing on this beam? If it should be hot and I should short circuit or bridge it with my body, it would be just too bad."

"We have made sure that nothing is connected to it," the Titanian assured him. "Do you think you can do anything?"

"Absolutely. We've got jacks that'll bend heavier stuff than that, and after we get it straightened the welding will be easy, but I'll have to have some metal. Shall I cut a piece off the pavement outside?"

"That will not be necessary. You will find ample stores of space metal piled at the base of each pillar."

"All x. Now we'll get the jack, Nadia," and they went back to their vessel, finding that upon Saturn, their combined strength was barely sufficient to drag the heavy tool along the floor.

"Stand aside, please. We will place it for you," a calm voice sounded in their ears, and a pale blue tractor beam picked the massive jack lightly from the floor, and as lightly lifted it to its place beneath the broken bus-bar and held it there while Stevens piled blocks and plates of platinum beneath its base.

"Well, here's where I peel down as far as the law allows. This is going to be real work, girl—no fooling. It'd help a lot if this outfit were sending out a few thousand kilo-franks instead of standing idle."

"How would that help?"

"It's a heat-engine, you know—works by absorbing heat. The cold air sinks—I imagine it pretty nearly blows a gale down the side of this cone when it's working—and hot air rushes in to take its place. I could use a little cool breeze right now," and Stevens, stripped to the waist, bent to the lever of the powerful hydraulic jack.

Beads of sweat gathered upon his broad back, uniting to form tiny rivulets, and the girl became highly concerned about him.

"Let me help you, Steve—I'm pretty husky, too, you know."

"Sure you are, ace, but this is a job for a truck-horse, not a tenderly-nurtured maiden of the upper classes. You can help, though, by breaking out that welding outfit and getting it ready while I'm doing this bending to prepare for the welding."

Under the urge of that mighty jack the ends of the broken bus-bar rose into place, while far off in space the Titanians clustered about their visiray screens, watching, in almost unbelieving amazement, the supernatural being who labored in that reeking inferno of heat and poisonous vapor—who labored almost naked and entirely unprotected, refreshing himself from time to time with drafts of molten water!

"All x, Barkovis—that's high, I guess." Stevens flipped perspiration from his hot forehead with a wet finger and straightened his weary back. "Now you can put this jack away where we had it. Then you might trundle me over enough of that spare metal to fill up this hole, and I'll put on my suit and goggles and practice welding on this floor and the roof, to get the feel of the metal before I tackle the bar."

The hole in the floor was filled with scrap and soon sparks were flying wildly as the searing beam of Stevens' welding projector bit viciously into the stubborn alloy of noble metals; fashioning a smooth, solid floor where the yawning aperture had been. Then, lifted with his tools and plates to the roof, the man repaired that hole also.

"Now I know enough about it to do a good job on the bar," he decided, and brick after brick of alloy was fused into the crack, until only a smoothly rounded bulge betrayed that a break had ever existed in that mighty rod of metal.

"Give 'em the signal to draw power, and see if that's all that was the matter," Stevens instructed, as he relaxed in the grateful coolness of their control room. "Whew, that was a warm job, Nadia—and this air of ours does smell good!"

* * * * *

"It was a horrible job, and I'm glad it's done," she declared. "But say, Steve, that thing looks as little like a power-plant as anything I can imagine. How does it work? You said that it worked on heat, but I don't quite see how. But don't draw diagrams and please don't integrate!"

"No ordinary plant such as we use could run for centuries without attention," he replied. "This is a highly advanced heat-engine—something like a thermo-couple, you know. This whole thing is simply the hot end, connected to the cold end on Titan by a beam instead of wires. When it's working, this metal must cool off something fierce. That's what the checkerwork and fins are for—so that it can absorb the maximum amount of heat from the current of hot, moist air I spoke about. It's a sweet system—we'll have to rig up one between Tellus and the moon. Or even between the Equator and the Arctic Circle there'd be enough thermal differential to give us a million kilofranks. We haven't got the all x signal yet, but it's working—look at it sweat as it cools down!"

"I'll say it's sweating—the water is simply streaming off it!" In their plate they saw that moisture was already beginning to condense upon the heat-absorber: moisture running down the fins in streams and creeping over the dull metal floor in sluggish sheets; moisture which, turning into ice in the colder interior of the checkerwork, again became fluid at the inrush of hot, wet Saturnian air.

"There's the signal—all x, Barkovis? By the way it's condensing water, it seems to be functioning again."

"Perfect!" came the Titanian's enthusiastic reply, "You two planet-dwellers have done more in three short hours than the entire force of Titan could have accomplished in months. You have earned, and shall receive, the highest...."

"As you were, ace!" Stevens interrupted, embarrassed. "This job was just like shooting fish down a well, for us. Since you saved our lives, we owe you a lot yet. We're coming out—straight up!"

The Forlorn Hope shot upward, through mile after mile of steaming fog, until at last she broke through into the light, clear outer atmosphere. Stevens located the Titanian space-ship, and the two vessels once more hurtling together through the ether toward Titan, he turned to his companion.

"Take the controls, will you, Nadia? Think I'll finish up the tube. I brought along a piece of platinum from the power plant, and something that I think is tantalum from Barkovis' description of it. With those and the fractions we melted out, I think I can make everything we'll need."

Now that he had comparatively pure metal with which to work, drawing the leads and filaments was relatively a simple task. Working over the hot-bench with torch and welding projector, he made short work of running the leads through the almost plastic glass of the great tube and of sealing them in place. The plates and grids presented more serious problems; but they were solved and, long before Titan was reached, the tube was out in space, supported by a Titanian tractor beam between the two vessels. Stevens came into the shop, holding a modified McLeod gauge which he had just taken from the interior of the tube. When it had come to equilibrium, he read it carefully and yelled.

"Eureka, little fellow! She's down to where I can't read it, even on this big gauge—so hard that it won't need flashing—harder than any vacuum I ever got on Tellus, even with a Rodebush-Michalek super-pump!"

"But how about occluded and absorbed gas in the filaments and so on when they heat up?" demanded Nadia, practically.

"All gone, ace. I out-gassed 'em plenty out there—seven times, almost to fusion. There isn't enough gas left in the whole thing to make a deep breath for a microbe."

He took up his welding projector and a beam carried him back to the tube. There, in the practically absolute vacuum of space, the last openings in the glass were sealed, and man and great transmitting tube were wafted lightly back into the Terrestrial cruiser.

Hour after hour mirrored Titanian sphere and crude-fashioned terrestrial wedge bored serenely on through space, and it was not until Titan loomed large beneath them that the calm was broken by an insistent call from Titan to the sphere.

"Barkodar, attention! Barkodar, attention!" screamed from the speakers, and they heard Barkovis acknowledge the call.

"The Sedlor have broken through and are marching upon Titania. The order has gone out for immediate mobilization of every unit."

"There's that word 'Sedlor' again—what are they, anyway, Steve?" demanded Nadia.

"I don't know. I was going to ask him when he sprung it on us first, but he was pretty busy then and I haven't thought of it since. Something pretty serious, though—they've jumped their acceleration almost to Tellurian gravity, and none of them can live through much of that."

"Tellurians?" came the voice of Barkovis from the speaker. "We have just...."

"All x—we were on your wave and heard it," interrupted Stevens. "We're with you. What are those Sedlor, anyway? Maybe we can help you dope out something."

"Perhaps—but whatever you do, do not use your heat-projector. That would start a conflagration raging over the whole country, and we shall have enough to do without fighting fire. But it may be that you have other weapons, of which we are ignorant, and I can use a little time in explanation before we arrive. The Sedlor are a form of life, something like your..." he paused, searching through his scanty store of Earthly knowledge, then went on, doubtfully, "perhaps some thing like your insects. They developed a sort of intelligence, and because of their fecundity, adapted themselves to their environment as readily as did man; and for ages they threatened man's supremacy upon Titan. They devoured vegetation, crops, animals, and mankind. After a world-wide campaign, however, they were finally exterminated, save in the neighborhood of one great volcanic crater, which they so honeycombed that it is almost impregnable. All around that district we have erected barriers of force, maintained by a corps of men known as 'Guardians of the Sedlor.' These barriers extend so far into the ground and so high into the air that the Sedlor can neither burrow beneath them nor fly over them. They were being advanced as rapidly as possible, and in a few more years the insects would have been destroyed completely—but now they are again at large. They have probably developed an armor or a natural resistance greater than the Guardians thought possible, so that when the walls were weakened, they came through in their millions, underground and undetected. They are now attacking our nearest city—the one you know, and which you have called Titania."

"What do you use—those high-explosive bombs?"

"The bombs were developed principally for use against them, but proved worse than useless, for we found that when a Sedlor was blown to pieces, each piece forthwith developed into a new, complete creature. Our most efficient weapons are our heat rays—not yours remember—and poison gas. I must prepare our arms."

"Would our heat-ray actually set them afire, Steve?" Nadia asked, as the plate went blank.

"I'll say it would. I'll show you what heat means to them—showing you will be plainer than any amount of explanation," and he shot the visiray beam down toward the city of Titania. Into a low-lying building it went, and Nadia saw a Titanian foundry in full operation. Men clad in asbestos armor were charging, tending, and tapping great electric furnaces and crucibles; shrinking back and turning their armored heads away as the hissing, smoking melt crackled into the molds from their long-handled ladles. Nadia studied the foundry for a moment, interested, but unimpressed.

"Of course it's hot there—foundries always are hot," she argued.

"Yes, but you haven't got the idea yet." Stevens turned again to the controls, following the sphere toward what was evidently a line of battle. "That stuff that they are melting and casting and that is so hot, is not metal, but ice! Remember that the vital fluid of all life here, animal and vegetable, corresponding to our water, is probably more inflammable than gasoline. If they can't work on ice-water without wearing suits of five-ply asbestos, what would a real heat-ray do to them? It'd be about like our taking a dive into the sun!"

"Ice!" she exclaimed. "Oh of course—but you couldn't really believe a thing like that without seeing it, could you? Oh, Steve—how utterly horrible!"

* * * * *

The "Barkodar" had dropped down into a line of sister ships, and had gone into action in midair against a veritable swarm of foes. Winged centipedes they were—centipedes fully six feet long, hurling themselves along the ground and through the air in furious hordes. From the flying globes emanated pale beams of force, at the touch of which the Sedlor disappeared in puffs of vapor. Upon the ground huge tractors and trucks, manned by masked soldiery, mounted mighty reflectors projecting the same lethal beam. From globes and tanks there sounded a drumming roar and small capsules broke in thousands among the foe; emitting a red cloud of gas in which the centipedes shriveled and died. But for each one that was destroyed two came up from holes in the ground and the battle-line fell back toward Titania, back toward a long line of derrick-like structures which were sinking force-rods into the ground in furious haste.

Stevens flashed on his ultra-violet projector and swung it into the thickest ranks of the enemy. In the beam many of the monsters died, but the Terrestrial ray was impotent compared with the weapons of the Titanians, and Stevens, snapping off the beam with a bitter imprecation, shot the visiray out toward the bare, black cone of the extinct volcano and studied it with care.

"Barkovis, I've got a thought!" he snapped into the microphone. "Their stronghold is in that mountain, and there's millions of them in there yet, coming out along their tunnels. They've got all the vegetation eaten away for miles, so there's nothing much left there to spread a fire if I go to work on that hill, and, I'll probably melt enough water to put out most of the fires I start. Detail me a couple of ships to drop your fire-foam bombs on any little blazes that may spread, and I'll give them so much to worry about at home, that they'll forget all about Titania."

The Forlorn Hope darted toward the crater, followed closely by two of the dazzling globes. They circled the mountain until Stevens found a favorable point of attack—a stupendous vertical cliff of mingled rock and crystal, upon the base of which he trained his terrific infra-red projector.

"I'm going to draw a lot of power," he warned the Titanians then. "I'm giving this gun everything she'll take."

He drove the massive switches in, and as that dull red beam struck the cliff's base there was made evident the awful effect of a concentrated beam of real and pure heat upon such an utterly frigid world. Vast columns of fire roared aloft, helping Stevens, melting and destroying the very ground as the bodies of the Sedlor in that gigantic ant-heap burst into flames. Clouds of superheated steam roared upward, condensing into a hot rain which descended in destructive torrents upon the fastnesses of the centipedes. As the raging beam ate deeper and deeper into the base of the cliff, the mountain itself began to disintegrate; block after gigantic block breaking off and crashing down into the flaming, boiling, seething cauldron which was the apex of that ravening beam.

Hour after hour Stevens drove his intolerable weapon into the great mountain, teeming with Sedlorean life; and hour after hour a group of Titanian spheres stood by, deluging the surrounding plain with a flood of heavy fumes, through which the holocaust could not spread for lack of oxygen. Not until the mountain was gone—not until in its stead there lay a furiously boiling lake, its flaming surface hundreds of feet below the level of the plain—did Stevens open his power circuits and point the deformed prow of the Forlorn Hope toward Titania.



CHAPTER VII

The Return to Ganymede

"Must you you go back to Ganymede?" Barkovis asked, slowly and thoughtfully. He was sitting upon a crystal bench beside the fountain, talking with Stevens, who, dressed in his bulging space-suit, stood near an airlock of the Forlorn Hope. "It seems a shame that you should face again those unknown, monstrous creatures who so inexcusably attacked us both without provocation."

"I'm not so keen on it myself, but I can't see any other way out of it," the Terrestrial replied. "We left a lot of our equipment there, you know; and even if I should build duplicates here, it wouldn't do us any good. These ten-nineteens are the most powerful transmitting tubes known when we left Tellus, but even their fields, dense as they are, can't hold an ultra-beam together much farther than about six astronomical units. So you see we can't possibly reach our friends from here with this tube; and your system of beam transmission won't hold anything together even that far, and won't work on any wave shorter than Roeser's Rays. We may run into some more of those little spheres, though, and I don't like the prospect. I wonder if we couldn't plate a layer of that mirror of yours upon the Hope and carry along a few of those bombs? By the way, what is that explosive—or is it something beyond Tellurian chemistry?"

"Its structure should be clear to you, although you probably could not prepare it upon Tellus because of your high temperature. It is nothing but nitrogen—twenty-six atoms of nitrogen combined to form one molecule of what you would call—N-twenty-six?"

"Wow!" Stevens whistled. "Crystalline, pentavalent nitrogen—no wonder it's violent!"

"We could, of course, cover your vessel with the mirror, but I am afraid that it would prove of little value. The plates are so hot that it would soon volatilize."

"Not necessarily," argued Stevens. "We could live in number one life-boat, and shut off the heat everywhere else. The life-boats are insulated from the structure proper, and the inner and outer walls of the structure are insulated from each other. With only the headquarters lifeboat warm, the outer wall could be held pretty close to zero absolute."

"That is true. The bombs, of course, are controlled by radio, and therefore may be attached to the outer wall of your vessel. We shall be glad to do these small things for you."

The heaters of the Forlorn Hope were shut off, and as soon as the outer shell had cooled to Titanian temperature, a corps of mechanics set to work. A machine very like a concrete mixer was rolled up beside the steel vessel, and into its capacious maw were dumped boxes and barrels of dry ingredients and many cans of sparkling liquid. The resultant paste was pumped upon the steel plating in a sluggish, viscid stream, which spread out into a thick and uniform coating beneath the flying rollers of the skilled Titanian workmen. As it hardened, the paste smoothed magically into the perfect mirror which covered the space-vessels of the satellite; and a full dozen of the mirror explosive bombs of this strange people were hung in the racks already provided.

"Once again I must caution you concerning those torpedoes," Barkovis warned Stevens. "If you use them all, very well, but do not try to take even one of them into any region where it is very hot, for it will explode and demolish your vessel. If you do not use them, destroy them before you descend into the hot atmosphere of Ganymede. The mirror will volatilize harmlessly at the temperature of melting mercury, but the torpedoes must be destroyed. Once more, Tellurians, we thank you for what you have done, and wish you well."

"Thanks a lot for your help—we still owe you something," replied Stevens. "If either of your power-plants go sour on you again, or if you need any more built, be sure to let us know—you can come close enough to the inner planets now on your own beam to talk to us on the ultra-communicator. We'll be glad to help you any way we can—and we may call on you for help again. Goodbye, Barkovis—goodbye, all Titania!"

He made his way through the bitterly cold shop into the control-room of their lifeboat, and while he was divesting himself of his heavy suit, Nadia lifted the Forlorn Hope into the blue-green sky of Titan, accompanied by an escort of the mirrored globes. Well clear of the atmosphere of the satellite, the terrestrial cruiser shot forward at normal acceleration, while the Titanian vessels halted and wove a pattern of blue and golden rays in salute to the departing guests.

"Well, Nadia, we're off—on a long trek, too."

"Said Wun Long Hop, the Chinese pee-lo," Nadia agreed. "Sure everything's all x, big boy?"

"To nineteen decimals," he declared. "You couldn't squeeze another frank into our accumulators with a proof-bar, and since they're sending us all the power we want to draw, we won't need to touch our batteries or tap our own beam until we're almost to Jupiter. To cap the climax, what it takes to make big medicine on those spherical friends of ours, we've got. We're not sitting on top of the world, ace—we've perched exactly at the apex of the entire universe!"

"How long is it going to take?"

"Don't know. Haven't figured it yet, but it'll be beaucoup days," and the two wanderers from far-distant Earth settled down to the routine of a long and uneventful journey.

They gave Saturn and his spectacular rings a wide berth and sped on, with ever-increasing velocity. Past the outer satellites, on and on, the good ship Forlorn Hope flew into the black-and-brilliant depths of interplanetary space. Saturn was an ever-diminishing disk beneath them: above them was Jupiter's thin crescent, growing ever larger and more bright, and the Monarch of the Solar System, remaining almost stationary day after day, increasing steadily in apparent diameter and in brilliance.

* * * * *

Although the voyage from Titan to Ganymede was long, it was not monotonous, for there was much work to be done in the designing and fabrication of the various units which were to comprise the ultra-radio transmitting station. In the various compartments of the Forlorn Hope there were sundry small motors, blowers, coils, condensers, force-field generators, and other items which Stevens could use with little or no alteration; but for the most part he had to build everything himself. Thus it was that time passed quickly; so quickly that Jupiter loomed large and the Saturnian beam of power began to attenuate almost before the Terrestrials realized that their journey was drawing to an end.

"Our beam's falling apart fast," Stevens read his meters carefully, then swung his communicator beam toward Jupiter. "We aren't getting quite enough power to hold our acceleration at normal—think I'll cut now, while we're still drawing enough to let the Titanians know we're off their beam. We've got lots of power of our own now; and we're getting pretty close to enemy territory, so they may locate that heavy beam. Have you found Ganymede yet?"

"Yes, it will be on the other side of Jupiter by the time we get there. Shall I detour, or put on a little more negative and wait for it to come around to this side?"

"Better wait, I think. The farther away we stay from Jupiter and the major satellites, the better."

"All x—it's on. Suppose we'd better start standing watches, in case some of them show up?"

"No use," he dissented. "I've been afraid to put out our electro-magnetic detectors, as they could surely trace them in use. Without them, we couldn't spot an enemy ship even if we were looking right at it, except by accident; since they won't be lighted up and it's awfully hard to see anything out here, anyway. We probably won't know they're within a million kilometers until they put a beam on us. Barkovis says that this mirror will reflect any beam they can use, and I've already got a set of photo-cells in circuit to ring an alarm at the first flash off of our mirror plating. I'd like to get in the first licks myself, but I haven't been able to dope out any way of doing it. So you might as well sleep in your own room, as usual, and I'll camp here right under the panel until we get to Ganymede. There's a couple of little things I just thought of, though, that may help some; and I'm going to do 'em right now."

Putting on his space-suit, he picked up a power drill and went out into the bitter cold of the outer structure. There he attacked the inner wall of their vessel, and the carefully established inter-wall vacuum disappeared in a screaming hiss of air as the tempered point bit through plate after plate.

"What's the idea, Steve?" Nadia asked, when he had re-entered the control room. "Now you'll have all that pumping to do over again."

"Protection for the mirrors," he explained. "You see, they aren't perfect reflectors. There's a little absorption, so that some stuff comes through. Not much, of course; but enough to kill some of those Titanians and almost enough to ruin their ship got through in about ten minutes, and only one enemy was dealing it out. We can stand more than they could, of course, but the mirror itself won't stand much more heat than it was absorbing then. But with air in those spaces instead of vacuum, and with the whole mass of the Hope, except this one lifeboat, as cold as it is, I figure that there'll be enough conduction and convection through them to keep the outer wall and the mirror cold—cool enough, at least, to hold the mirror on for an hour. If only one ship tackles us, it won't be bad—but I figure that if there's only one, we're lucky."

* * * * *

Stevens' fears were only too well grounded, for during the "evening" of the following day, while he was carefully scanning the heavens for some sign of enemy craft, the alarm bell over his head burst into its brazen clamor. Instantly he shot out the detectors and ultra-lights and saw not one, but six of the deadly globes—almost upon them, at point-blank range! One was already playing a beam of force upon the Forlorn Hope, and the other five went into action immediately upon feeling the detector impulses and perceiving that the weapon of their sister ship had encountered an unusual resistance in the material of that peculiarly mirrored wedge. As those terrific forces struck her, the terrestrial cruiser became a vast pyrotechnic set piece, a dazzling fountain of coruscant brilliance: for the mirror held. The enemy beams shot back upon themselves and rebounded in all directions, in the same spectacular exhibition of frenzied incandescence which had marked the resistance of the Titanian sphere to a similar attack.

But Stevens was not idle. In the instant of launching his detectors, as fast as he could work the trips, four of the frightful nitrogen bombs of Titan—all that he could handle at once—shot out into space, their rocket-tubes flaring viciously. The enemy detectors of course located the flying torpedoes immediately, but, contemptuous of material projectiles, the spheres made no attempt to dodge, but merely lashed out upon them with their ravening rays. So close was the range that they had no time to avoid the radio-directed bombs after discovering that their beams were useless against the unknown protective covering of those mirrored shells. There were four practically simultaneous detonations—silent, but terrific explosions as the pent-up internal energy of solid pentavalent nitrogen was instantaneously released—and the four insensately murderous spheres disappeared into jagged fragments of wreckage, flying wildly away from the centers of explosion. One great mass of riven and twisted metal was blown directly upon the fifth globe, and Nadia stared in horrified fascination at the silent crash as the entire side of the ship crumpled inward like a shell of cardboard under the awful impact. That vessel was probably out of action, but Stevens was taking no chances. As soon as he had clamped a pale blue tractor rod upon the sixth and last of the enemy fleet, he drove a torpedo through the gaping wall and into the interior of the helpless war-vessel. There he exploded it, and the awful charge, detonated in that confined space, literally tore the globular space-ship to bits.

"We'll show these jaspers what kind of trees make shingles!" he gritted between clenched teeth; and his eyes, hard now as gray iron, fairly emitted sparks as he launched four torpedoes upon the sole remaining globe of the squadron of the void. "I've had a lot of curiosity to know just what kind of unnatural monstrosities can possibly have such fiendish dispositions as they've got—but beasts, men or devils, they'll find they've grabbed something this time they can't let go of," and fierce blasts of energy ripped from the exhausts as he drove his missiles, at their highest possible acceleration, toward the captive sphere so savagely struggling at the extremity of his tractor beam.

But that one remaining vessel was to prove no such easy victim as had its sister ships. Being six to one, and supposedly invincible, the squadron had been overconfident and had attacked carelessly, with only its crippling slicing beams instead of its more deadly weapons of total destruction; and so fierce and hard had been Stevens' counter-attack that five of its numbers had been destroyed before they realized what powerful armament was mounted by that apparently crude, helpless, and innocuous wedge. The sixth, however, was fully warned, and every resource at the command of its hellish crew was now being directed against the Forlorn Hope.

Sheets, cones, and gigantic rods of force flashed and crackled. Space was filled with silent, devastating tongues of flame. The Forlorn Hope was dragged about erratically as the sphere tried to dodge those hurtling torpedoes; tried to break away from the hawser of energy anchoring her so solidly to her opponent. But the linkage held, and closer and closer Stevens drove the fourfold menace of his frightful dirigible bombs. Pressor beams beat upon them in vain. Hard driven as those pushers were, they could find no footing, but were reflected at many angles by that untouchable mirror and their utmost force scarcely impeded the progress of the rocket-propelled missiles. Comparatively small as the projectiles were, however, they soon felt the effects of the prodigious beams of heat enveloping them, and torpedo after torpedo exploded harmlessly in space as their mirrors warmed up and volatilized. But for each bomb that was lost, Stevens launched another, and each one came closer to its objective than had its predecessor.

Made desperate by the failure of his every beam, the enemy commander thought to use material projectiles himself—weapons abandoned long since by his race as antiquated and inefficient, but a few of which were still carried by the older types of vessels. One such shell was found and launched—but in the instant of its launching Stevens' foremost bomb struck its mark and exploded. So close were the other three bombs, that they also let go at the shock; and the warlike sphere, hemmed in by four centers of explosions, flew apart—literally pulverized. Its projectile, so barely discharged, did not explode—it was loaded with material which could be detonated only by the warhead upon impact or by a radio signal. It was, however, deflected markedly from its course by the force of the blast, so that instead of striking the Forlorn Hope in direct central impact, its head merely touched the apex of the mirror-plated wedge. That touch was enough. There was another appalling concussion, another blinding glare, and the entire front quarter of the terrestrial vessel had gone to join the shattered globes.

Between the point of explosion and the lifeboats there had been many channels of insulation, many bulkheads, many air-breaks, and compartment after compartment of accumulator cells. These had borne the brunt of the explosion, so that the control room was unharmed, and Stevens swung his communicator rapidly through the damaged portions of the vessels.

"How badly are we hurt, Steve—can we make it to Ganymede?"

Nadia was quietly staring over his shoulder into the plate, studying with him the pictures of destruction there portrayed as he flashed the projector from compartment to compartment.

"We're hurt—no fooling—but it might have been a lot worse," he replied, as he completed the survey. "We've lost about all of our accumulators, but we can land on our own beam, and landing power is all we want, I think. You see, we're drifting straight for where Ganymede will be, and we'd better cut out every bit of power we're using, even the heaters, until we get there. This lifeboat will hold heat for quite a while, and I'd rather get pretty cold than meet any more of that gang. I figured eight hours just before they met us, and we were just about drifting then. I think it is safe to say seven hours blind."

"But can't they detect us anyway? They may have sent out a call, you know."

"If we aren't using any power for anything, their electr-omagnetics are the only things we'll register on, and they're mighty short-range finders. Even if they should get that close to us, they'll probably think we're meteoric, since we'll be dead to their other instruments. Luckily we've got lots of air, so the chemical purifiers can handle it without power. I'll shut off everything and we'll drift it. Couldn't do much of anything, anyway—even our shop out there won't hold air. But we can have light. We've got acetylene emergency lamps, you know, and we don't need to economize on oxygen."

"Perhaps we'd better run in the dark. Remember what you told me about their possible visirays, and that you've got only two bombs left."

"All x; that would be better. If I forget it, remind me to blow up those before we hit the atmosphere of Ganymede, will you?" He opened all the power switches, and, every source of ethereal vibrations cut off, the Forlorn Hope drifted slowly on, now appearing forlorn indeed.

* * * * *

Seven hours dragged past: seven age-long hours during which the two sat tense, expecting they knew not what, talking only at intervals and in subdued tones. Stevens then snapped on the communicator beam just long enough to take an observation upon Ganymede. Several such brief glimpses were taken; then, after a warning word to his companion, he sent out and exploded the nitrogen bombs. He then threw on the power, and the vessel leaped toward the satellite under full acceleration. Close to the atmosphere it slanted downward in a screaming, fifteen-hundred-mile drive; and soon the mangled wedge dropped down into the little canyon, which for so long had been "home."

"Well, colonel, home again!" Stevens exulted as he neutralized the controls. "There's that falls, our power plant, the catapults, 'n' everything. Now, unless something interrupts us again; we'll run up our radio tower and give Brandon the long yell."