Space Hounds of IPC

 (A Tale of the Inter-Plantary Corporation)

 By Edward E. Smith

  

 CHAPTER 1

 The IPV "Arcturus" Sets Out for Mars—

 A narrow football of steel, the Inter-Planetary Vessel Arcturus stood upright in her berth

 in the dock like an egg in its cup. A hundred feet across and a hundred and seventy feet

 deep was that gigantic bowl, its walls supported by the structural steel and concrete of

 the dock and lined with hard-packed bumper-layers of hemp and fiber. High into the air

 extended the upper half of the ship of space—a sullen gray expanse of fifty-inch

 hardened steel armor, curving smoothly upward to a needle prow. Countless hundreds

 of fine vertical scratches marred every inch of her surface, and here and there the

 stubborn metal was grooved and scored to a depth of inches—each scratch and score

 the record of an attempt of some wandering cosmic body to argue the right-of-way with

 the stupendous mass of that man-made cruiser of the void.

     A burly young man made his way through the throng about the entrance, nodded

 unconcernedly to the gatekeeper, and joined the stream of passengers flowing through

 the triple doors of the double air-lock and down a corridor to the center of the vessel.

 However, instead of entering one of the elevators which were whisking the passengers

 up to their staterooms in the upper half of the enormous football, he in some way

 caused an opening to appear in an apparently blank steel wall and stepped through it

 into the control room.

     "Hi, Breck!" the burly one called, as he strode up to the instrument-desk of the

 chief pilot and tossed his bag carelessly into a corner. "Behold your computer in the

 flesh! What's all this howl and fuss about poor computation?"

     "Ho, Steve!" The chief pilot smiled as he shook hands cordially. "Glad to see you

 again—but don't try to kid the old man. I'm simple enough to believe almost anything,

 but some things just aren't being done. We have been yelling, and yelling loud, for

 trained computers ever since they started riding us about every one-centimeter change

 in acceleration, but I know that you're no more an I-P computer than I am a Digger

 Indian. They don't shoot sparrows with coast-defense guns!"

     "Thanks for the compliment, Breck, but I'm your computer for this trip, anyway.

 Newton, the good old egg, knows what you fellows are up against and is going to do

 something about it, if he has to lick all the rest of the directors to do it. He knew that I

 was loose for a couple of weeks and asked me to come along this trip to see what I

 could see. I'm to check the observatory data—they don't know I'm aboard—take the

 peaks and valleys off your acceleration curve, if possible, and report to Newton just

 what I find out and what I think should be done about it. How early am I?" While the

 newcomer was talking, he had stripped the covers from a precise scale model of the

 solar system and from a large and complicated calculating machine and had set to work

 without a wasted motion or instant—scaling off upon the model the positions of the

 various check-stations and setting up long and involved integrals and equations upon

 the calculator.

     The older man studied the broad back of the younger, bent over his

 computations, and a tender, almost fatherly smile came over his careworn face as he

 replied:

     "Early? You? Just like you always were — minus fifteen seconds on zero. The

 final dope is due right now." He plugged the automatic recorder and speaker into a

 circuit marked "Observatory", waited until a tiny light above the plug flashed green, and

 spoke.

     "IPV Arcturus; Breckenridge, Chief Pilot; trip number forty three twenty nine.

 Ready for final supplementary route and flight data, Tellus to Mars."

     "Meteoric swarms still too numerous for safe travel along the scheduled route,"

 came promptly from the speaker. "You must stay further away from the plane of the

 ecliptic. The ether will be clear for you along route E2-P6-W4I-K3-Ri9-S7-Mi4. You will

 hold a constant acceleration of 981.27 centimeters between initial and final check

 stations. Your take-off will be practically unobstructed, but you will have to use the

 utmost caution in landing upon Mars, as in order to avoid a weightless detour and a loss

 of thirty one minutes you must pass very close to both the Martian satellites. To do so

 safely you must pass the last meteorological station, Mi4, on schedule time plus or

 minus five seconds, at scheduled velocity plus or minus ten meters, with exactly the

 given negative acceleration of 981.27 centimeters, and exactly upon the pilot ray Mi4

 will have set for you."

     "All x." Breckenridge studied his triplex chronometer intently, then unplugged and

 glanced around the control room, in various parts of which half a dozen assistants were

 loafing at their stations.

     "Control and power check-out — Hipe!" he barked. "Driving converters and

 projectors!"

     The first assistant scanned his meters narrowly as he swung a multi-point switch

 in a flashing arc. "Converter efficiency 100, projector reactivity 100; on each of numbers

 one to forty-five inclusive. All x."

     "Dirigible projectors!"

     Two more gleaming switches leaped from point to point. "Converter efficiency

 100, projector reactivity 100, dirigibility 100, on each of numbers one to thirty-two,

 inclusive, of upper band; and on each of numbers one to thirty-two, inclusive, of lower

 band. All x."

     "Gyroscopes!"

     "35,000. Drivers in equilibrium at ten degrees plus. All x."

     "Upper lights and lookout plates!"

     The second assistant was galvanized into activity, and upon a screen before him

 there appeared a view as though he were looking directly upward from the prow of the

 great vessel. The air above them was full of aircraft of all shapes and sizes, and

 occasionally the image of one of that flying horde flared into violet splendor upon the

 screen as it was caught in the mighty, roving beam of one of the twelve ultra-light

 projectors under test.

     "Upper lights and lookout plates—all x," the second assistant reported, and other

 assistants came to attention as the check-out went on.

     "Lower lights and lookout plates!"

     "All x," was the report, after each of the twelve ultralights of the stern had swung

 around in its supporting brackets, illuminating every recess of the dark depths of the

 bottom well of the berth and throwing the picture upon another screen in brilliant violet

 relief.

     "Lateral and vertical detectors!"

     "Laterals XP27io—all x. Verticals AJ429O—all x."

     "Receptors!"

     "15,270 kilofranks—all x."

     "Accumulators!"

     "700,000 kilofrank-hours—all x."

     Having thus checked and tested every function of his department, Breckenridge

 plugged into "Captain," and when the green light went on:

     "Chief pilot check-out—all x," he reported briefly.

     "All x," acknowledged the speaker, and the chief pilot unplugged. Fifteen minutes

 remained, during which time one department head after another would report to the

 captain of the liner that everything in his charge was ready for the stupendous flight.

     "All x, Steve?" Breckenridge turned to the computer. "How do you check

 acceleration and power with the observatory?"

     "Not so good, old bean," the younger man frowned in thought. "They figure like

 astronomers, not navigators. They've made no allowances for anything, not even the

 reversal—and I figure four thousandths for that and for minor detours. Then there's

 check-station error . . ."

     "Check-station errors! Why, they're always right— that's what they're for!"

     "Don't fool yourself—they've got troubles of their own, the same as anybody else.

 In fact, from a study of the charts of the last few weeks, I'm pretty sure that E 2 is at

 least four thousand kilometers this side of where he thinks he is, that W4i is ten or

 twelve thousand beyond his station, and that they've both got a lateral displacement

 that's simply fierce. I'm going to check up, and argue with them about it as we pass.

 Then there's another thing—they figure to only two places, and we've got to have the

 third place almost solid if we expect to get a smooth curve. A hundredth of a centimeter

 of acceleration means a lot on a long trip when they're holding us as close as they are.

 We'll ride this trip on 981.286 centimeters—with our scheduled mass that means thirty

 six point oh four seven kilofranks plus equilibrium power. All set to go," the computer

 stated, as he changed, by fractions of seconds of arc, the course-plotters of the

 automatic integrating goniometer.

     "You're the doctor—but I'm glad it's you that'll have to explain to the observatory,"

 and Breckenridge set his exceedingly delicate excess power potentiometer exactly upon

 the indicated figure. "Well, we've got a few minutes left for a chin-chin before we lift her

 off."

     "What's all this commotion about? Dish out the low-down."

     "Well, it's like this, Steve. We pilots are having one sweet time—we're being

 growled at on every trip. The management squawks if we're thirty seconds plus or

 minus at the terminal, and the passenger department squalls if we change acceleration

 five centimeters total enroute—claims it upsets the dainty customers and loses business

 for the road. They're tightening up on us all the time. A couple of years ago, you

 remember, it didn't make any difference what we did with the acceleration as long as we

 checked in somewhere near zero time—we used to spin 'em dizzy when we reversed at

 the halfway station—but that kind of stuff doesn't go any more. We've got to hold the

 acceleration constant and close to normal, got to hold our schedule on zero, plus or

 minus ten seconds, and yet we've got to make any detours they tell us to, such as this

 seven-million kilometer thing they handed us just now. To make things worse, we've got

 to take orders at every check-station, and yet we get the blame for everything that

 happens as a consequence of obeying those orders! Of course, I know as well as you

 do that it's rotten technique to change acceleration at every check-station; but we've told

 'em over and over that we can't do any better until they put a real computer on every

 ship and tell the check-stations to report meteorites and other obstructions to us and

 then to let us alone. So you'd better recommend us some computers!"

     "You're getting rotten computation, that's a sure thing, and I don't blame you

 pilots for yelling, but I don't believe that you've got the right answer. I can't help but think

 that the astronomers are laying down on the job. They're so sure that you pilots are to

 blame that it hasn't occurred to them to check up on themselves very carefully.

 However, we'll know pretty quick, and then we'll take steps."

     "I hope so—but say, Steve, I'm worried about using that much plus equilibrium

 power. Remember we've got to hit Mi4 absolutely all x, or plenty heads will drop."

     "I'll say they will: I know just how the passengers will howl if we hold them

 weightless for half an hour, waiting for those two moons to get out of the way, and I

 know just what the manager will do if we check in thirty-one minutes plus. Wow! He'll

 swell up and bust, sure. But don't worry, Breck—if we don't check in all x, anybody can

 have my head that wants it, and I'm taking full responsibility, you know."

     "You're welcome to it." Breckenridge shrugged and turned the conversation into a

 lighter vein. "Speaking of weightlessness, it's funny how many weight-fiends there are in

 the world, isn't it? You'd think the passengers would enjoy a little weightlessness

 occasionally—especially the fat ones—but they don't. But say, while I think of it, how

 come you were here and loose to make this check-up? I thought you were out with the

 other two of the Big Three, solving all the mysteries of the Universe ?"

     "Had to stay in this last trip—been doing some work on the ether, force-field

 theory, and other stuff that I had to go to Mars and Venus to get. Just got back last

 week. As for solving mysteries, laugh while you can, old hyena. You and a lot of other

 dim bulbs who think that Roeser's Rays are the last word—that there's nothing left to

 discover—are going to get jarred loose from your hinges one of these days. When I

 came in nine months ago they were hot on the trail of something big, and I'll bet they

 bring it in . . ."

     Out upon the dock an insistent siren blared a crescendo and diminuendo blast of

 sound, and two minutes remained. In every stateroom and in every lounge and saloon

 speakers sounded a warning:

     "For a short time, while we are pulling clear of the gravitational field of the Earth,

 walking will be somewhat difficult, as everything on board will apparently increase in

 weight by about one-fifth of its present amount. Please remain seated, or move about

 with caution. In about an hour weight will gradually return to normal. We start in one

 minute."

     "Hipe!" barked the chief pilot as a flaring purple light sprang into being upon his

 board, and the assistants came to attention at their stations. "Seconds! Four! Three!

 Two! One! LIFT!" He touched a button and a set of plunger switches drove home,

 releasing into the forty-five enormous driving projectors the equilibrium power—the

 fifteen-thousand-and-odd kilofranks of energy that exactly counterbalanced the pull of

 gravity upon the mass of the cruiser. Simultaneously there was added from the

 potentiometer, already set to the exact figure given by the computer, the plus-

 equilibrium power — which would not be changed throughout the journey if the ideal

 acceleration curve were to be registered upon the recorders—and the immense mass of

 the cruiser of the void wafted vertically upward at a low and constant velocity. The

 bellowing, shrieking siren had cleared the air magically of the swarm of aircraft in her

 path, and quietly, calmly, majestically, the Arcturus floated upward.

     Sixty seconds after the initial lift Breckenridge actuated the system of magnetic

 relays which would gradually cut in the precisely-measured "starting power," which it

 would be necessary to employ for sixty-nine minutes—for, without the acceleration

 given by this additional power, they would lose many precious hours of time in covering

 merely the few thousands of miles during which Earth's attraction would operate

 powerfully against their progress.

     Faster and faster the great cruiser shot upward as more and more of the starting

 power was released, and heavier and heavier the passengers felt themselves become.

 Soon the full calculated power was on and the acceleration became constant. Weight

 no longer increased, but remained constant at a value of plus twenty three and six-

 tenths percent. For a few moments there had been uneasy stomachs among the

 passengers—perhaps a few of the first-trippers had been made ill—but it was not much

 worse than riding in a highspeed elevator, particularly since there was no change from

 positive to negative acceleration such as is experienced in express elevators.

     The computer, his calculations complete, watched the pilot with interest, for,

 accustomed as he was to traversing the depths of space, there was a never-failing thrill

 to his scientific mind in the delicacy and precision of the work which Breckenridge was

 doing—work which could be done only by a man having had long training in the

 profession and possessed of almost instantaneous nervous reactions and of the highest

 degree of manual dexterity and control. Under his right and left hands were the double-

 series potentiometers actuating the variable-speed drives of -the flight-angle directors in

 the hour and declination ranges; before his eyes was the finely-marked micrometer

 screen upon which the goniometer threw its needle-point of light; powerful optical

 systems of prisms and lenses revealed to his sight the director-angles, down to

 fractional seconds of arc. It was the task of the chief pilot to hold the screened image of

 the cross hairs of the two directors in such position relative to the ever-moving point of

 light as to hold the mighty vessel , precisely upon its course, in spite of the complex

 system of forces acting upon it.

     For almost an hour Breckenridge sat motionless, his eyes flashing from,

 micrometer screen to signal panel, his sensitive fingers moving the potentiometers

 through minute arcs because of what he saw upon the screen and in response to the

 flashing, multicolored lights and tinkling signals of his board. Finally, far from Earth, the

 moon's attraction and other perturbing forces comparatively slight, the signals no longer

 sounded and the point of light ceased its irregular motion, becoming almost stationary.

 The chief pilot brought both cross-hairs directly upon the brilliant point which for some

 time they had been approaching more and more nearly, adjusted the photo-cells and

 amplifiers which would hold them immovably upon it, and at the calculated second of

 time cut out the starting power by means of another set of automatically-timed relays.

 When only the regular driving power was left, and the acceleration had been checked

 and found to be exactly the designated value of 981.286 centimeters, he stood up,

 stretched, and heaved a profound sigh of relief.

     "Well, Steve, that's over with—we're on our way. I'm always glad when this part

 of it is done."

     "It's a ticklish job, no fooling—even for an expert," the mathematician agreed. "No

 wonder the astronomers think you birds are the ones who are gumming up their dope.

 Well, it's about time to plug in on E2. Here's where the fireworks start!" He closed the

 connections which transferred the central portion of the upper lookout screen to a small

 micrometer screen at Breckenridge's desk and plugged it into the first check-station.

 Instantly a point of red light, surrounded by a vivid orange circle, appeared upon the

 screen, low down and to the left of center, and the timing galvanometer showed a wide

 negative deflection.

     "Hashed again!" growled Breckenridge. "I must be losing my grip, I guess. I put

 everything I had on that sight, and missed it ten divisions. I think I'll turn in my

 badge—I've cocked our perfect curve already, before we got to the first check-station!"

 His hands moved toward the controls, to correct their course and acceleration.

     "As you were—hold everything! Lay off those controls!" snapped the computer.

 "There's something screwy, just as I thought—and it isn't you, either. I'm no pilot, of

 course, but I do know good compensation when I see it, and if you weren't

 compensating that point I never saw it done. Besides, with your skill and my figures I

 know damn well that we aren't off more than a tenth of one division. He's cuckoo! Don't

 call him — let him start it, and refer him to me."

     "All x—I'll be only too glad to pass the buck. But I still think, Steve, that you're

 playing with dynamite. Who ever heard of an astronomer being wrong?"

     "You'd be surprised," grinned the physicist. "Since this fuss has just started,

 nobody's tried to find out whether they were wrong or not . . ."

     "IPV Arc turns, attention!" came from the speaker curtly.

     "IPV Arcturus, Breckenridge," acknowledged the chief pilot.

     "You have been on my ray almost a minute. Why are you not correcting course

 and acceleration?"

     "Doctor Stevens is computing us and has full control of course and acceleration,"

 replied Breckenridge. "He will answer you."

     "I am changing neither course nor acceleration because you are not in position,"

 declared Stevens, crisply. "Please give me your present supposed location, and your

 latest precision goniometer bearings on the sun, the moon, Mars, Venus, and your

 Tellurian reference limb, with exact time of observations, gyroscope zero-planes, and

 goniometer factors!"

     "Correct at once or I shall report you to the Observatory," E2 answered loftily,

 paying no attention to the demand for proof of position.

     "Be sure you do that, guy—and while you're at it report that your station hasn't

 taken a precision bearing in a month. Report that you've been muddling along on loop

 bearings, and that you don't know where you are, within seven thousand kilometers.

 And speaking of reporting—I know already that a lot of you astronomical guessers have

 only the faintest possible idea of where you really are, plus, minus, or lateral; and if you

 don't get yourselves straightened out before we get to W4i I'm going to make a report

 on my own account that will jar some of you birds loose from your upper teeth!" He

 unplugged with a vicious jerk, and turned to the pilot with a grin.

     "Guess that'll hold 'im for a while, won't it, old egg?"

     "He'll report us, sure," remonstrated Breckenridge. The older man was plainly ill

 at ease at this open defiance of the supposedly infallible check-stations.

     "Not that baby," returned the computer confidently. "I'll bet you a small farm

 against a plugged nickel that right now he's working his goniometer so hard that its

 pivots are getting hot. He'll sneak back into position as soon as he can calculate his

 results, and pretend he's always been there."

     "The others will be all right, then, probably, by the time we get to them ?"

     "Gosh, no—you're unusually dumb today, Breck. He won't tell anybody

 anything—he doesn't want to be the only goat, does he?"

     "Oh, I see. How could you dope this out, with only the recorder charts ?"

     "Because I know the kind of stuff you pilots are—and those humps are altogether

 too big to be accounted for by anything I know about you. Another thing—the next

 station, P6, I think is keeping himself all x. If so, when you corrected for E2, which was

 wrong, it'd throw you all off on P6, which was right, and so on—a bad hump at almost

 every check-station. See?"

     True to prediction, the pilot ray of P6 came in almost upon the exact center of the

 micrometer screen, and Breckenridge smiled in relief as he began really to enjoy the

 trip.

     "How do we check on chronometers ?" asked P6 when Stevens had been

 introduced. "By my time you seem to be about two and a half seconds minus?"

     "All x—two point four I figure it—we're riding on 981.286 centimeters, to allow for

 the reversal and for minor detours. 'Bye."

     "All this may have been coincidence, Breck, but we'll find out pretty quick now,"

 the computer remarked when the flying vessel was nearing the third check-station.

 "Unless I'm all out of control we'll check in almost fourteen seconds plus on W4i, and we

 may not even find him on the center block of the screen."

     When he plugged in W4i was on the block, but was in the extreme upper right

 corner. They checked in thirteen and eight-tenths seconds late, and a fiery dialogue

 ensued when the computer questioned the accuracy of the location of the station and

 refused point-blank to correct his course.

     "Well, Breck, old onion, that tears it," Stevens declared as he unplugged. "No use

 going any further on these lousy reference points. I'm going to report to Newton—he'll

 rock the observatory on its foundations!" He plugged into the telegraph room. "Have you

 got a free high-power wave? . . . Please put me on Newton, in the main office."

     Moving lights flashed and flickered for an instant upon the communicator screen,

 settling down into a white glow which soon resolved itself into the likeness of a keen-

 eyed, gray-haired man, seated at his desk in the remote office of the Inter-Planetary

 Corporation. Newton smiled as he recognized the likeness of Stevens upon his own

 screen, and greeted him cordially.

     "Have you started your investigation, Doctor Stevens ?"

     "Started it? I've finished it!" and Stevens tersely reported what he had learned,

 concluding: "So you see, you don't need special computers on these ships any more

 than a hen needs teeth. You've got all the computers you need, in the

 observatories—all you've got to do is make them work at their trade."

     "The piloting was all x, then?"

     "Absolutely—our curve so far is exactly flat ever since we cut off the starting

 power. Of course, all the pilots can't be as good as Breckenridge, but give them good

 computation and good check points and you shouldn't get any humps higher than about

 half a centimeter."

     "They'll get both, from now on," the director assured him. "Thanks. If your work

 for the trip is done, you might show my little girl, Nadia, around the Arcturus. She's

 never been out before, and will be interested. Would you mind?"

     "Glad to, Mr. Newton—I'll be a regular uncle to her."

     "Thanks again. Operator, I'll speak to Captain King, please."

     "Pipe down that guff, you unlicked cub, or I'll crown you with a proof-bar!" the

 chief pilot growled, as soon as Stevens had unplugged.

     "You and who else?" retorted the computer, cheerfully. "Pipe down yourself, guy

 — if you weren't so dumb and didn't have such a complex you'd know that you're the

 crack pilot of the outfit and wouldn't care who else knew it." Stevens carefully covered

 and put away the calculating machine and other apparatus he had been using, and

 turned again to the pilot.

     "I didn't know Newton had any kids, especially little ones? Of course I don't know

 him very well, since I've never been around the office much, but the old tiger goes over

 big with me."

     "Hm-m. Think you'll enjoy playing nursemaid all the rest of the trip?"

 Breckenridge asked caustically, but with an enigmatic smile.

     "Think so? I know so!" replied Stevens, positively. "I always did like kids, and

 they like me—we fall for each other like ten thousand bricks falling down a well. Why, a

 kid—any kid—and I team up just like grace and poise . . . What's gnawing on you

 anyway, to make you turn Cheshire cat all of a sudden ? By the looks of that grin I'd say

 you'd swallowed a canary of mine some way or other; but darned if I know that I've lost

 any," and he stared at his friend suspiciously.

     "To borrow your own phrase, Steve, 'You'd be surprised,' " and Breckenridge,

 though making no effort to conceal his amusement, would say no more.

     In a few minutes the door opened, and through it there stepped a grizzled four-

 striper. Almost hidden behind his massive form there was a girl, who ran up to

 Breckenridge and seized both his hands, her eyes sparkling.

     "Hi, Breckie, you old darling! I knew that if we both kept after him long enough

 Dad would let me ride with you sometime. Isn't this gorgeous?"

     Stevens was glad indeed that the girl's enthusiastic greeting of the pilot was

 giving him time to recover from his shock, for Director Newton's "little girl, Nadia" was

 not precisely what he had led himself to expect. Little she might be, particularly when

 compared with the giant frame of Captain King, or with Steve's own five-feet-eleven of

 stature and the hundred and ninety pounds of rawhide and whalebone that was his

 body, but child she certainly was not. Her thick, fair hair, cut in the square bob that was

 the mode of the moment, indicated that Nature had intended her to be a creamy blonde,

 but as she turned to be introduced to him Stevens received another surprise—for she

 was one of those rare, but exceedingly attractive beings, a natural blonde with brown

 eyes and black eyebrows. Sun and wind had tanned her satin skin to a smooth and

 even shade of brown, and every movement of her lithe and supple body bespoke to the

 discerning mind a rigidly-trained physique.

     "Doctor Stevens, you haven't met Miss Newton, I hear," the captain introduced

 them informally. "All the officers who are not actually tied down at their posts are

 anxious to do the honors of the vessel, but as I have received direct orders from the

 owners I am turning her over to you—you are to show her around."

     "Thanks, Captain, I won't mutiny a bit against such an order as that. I'm mighty

 glad to know you, Miss Newton."

     "I've heard a lot about you, Doctor. Dad and Breckie here are always talking

 about the Big Three—what you have done and what you are going to do. I want to meet

 Doctor Brandon and Doctor Westfall, too," and her hand met his in a firm and friendly

 clasp. She turned to the captain, and Stevens, noticing that the pilot, with a quizzical

 expression, was about to say something, silenced him with a fierce aside.

     "Clam it, ape, or I'll climb up you like a squirrel!" he hissed, and the grinning

 Breckenridge nodded assent to this demand for silence concerning children and

 nursemaids.

     "Since you've never been out, Miss Newton, you'll want to see the whole works,"

 Stevens addressed the girl. "Where do you want to begin? Shall we start at the top and

 work down?"

     "All x," she agreed, and fell into step behind him. She was dressed in dove-gray

 from head to foot—toque, blouse, breeches, heavy stockings, and shoes were of the

 one shade of smooth, lustrous silk; and as they strolled together down the passage-way

 the effortless ease and perfect poise of her carriage called aloud to every hard-schooled

 fiber of his own being.

     "We're a lot alike, you and I—do you know it?" he asked, abruptly and

 unconventionally.

     "Yes, I've felt it, too," she replied frankly, and studied him without affectation. "It

 has just come to me what it is. We're both trained down fine. You're an athlete of some

 kind, and I'm sure you're a star—I ought to recognize you, but I'm ashamed to say I

 don't. What do you do?"

     "Swim."

     "Oh, of course—Stevens, the great Olympic high and fancy diver! I'd never have

 connected our own Doctor Stevens, the eminent mathematical physicist, with the King

 of the Springboard. Say, ever since I quit being afraid of the water I've had a yen to do

 that two-and-a-half thing of yours, but I've never seen anybody that knew it well enough

 to teach it to me, and I've almost broken my back forty times trying to learn it alone!"

     "I've got you, now, too—American and British Women's golf champion. Shake!"

 and the two shook hands vigorously, in mutual congratulation. "Tell you what—I'll give

 you some pointers on diving, and you can show me how to make a golf ball behave.

 Next to Norman Brandon I've got the most vicious hook in captivity—and Norm can't

 help himself. He's left-handed, you know, and, being a southpaw, he's naturally wild. He

 slices all his woods and hooks all his irons. I'm consistent, anyway—I hook everything,

 even my putts."

     "It's a bargain! What do you shoot?"

     "Pretty dubby. Usually in the middle eighties—none of us play much, being out in

 space most of the time, you know—sometimes, when my hook is going particularly well,

 I go up into the nineties."

     "We'll lick that hook," she promised, as they entered an elevator and were borne

 upward, toward the prow of the great interplanetary cruiser.
 CHAPTER 2

— But Does Not Arrive

 All out—we climb the rest of the way on foot," Stevens told his companion, as the

 elevator stopped at the uppermost passenger floor. They walked across the small

 circular hall and the guard on duty came to attention and saluted as they approached

 him.

     "I have orders to pass you and Miss Newton, sir. Do you know all the

 combinations?"

     "I know this good old tub better than the men that built her—I helped calculate

 her," Stevens replied, as he stepped up to an apparently blank wall of steel and deftly

 manipulated an almost invisible dial set flush with its surface. "This is to keep the

 passengers where they belong," he explained, as a section of the wall swung backward

 in a short arc and slid smoothly aside. "We will now proceed to see what makes her

 tick."

     Ladder after ladder of steel they climbed, and bulkhead after bulkhead opened at

 Stevens' knowing touch. At each floor the mathematician explained to the girl the

 operation of the machinery there automatically at work—devices for heating and

 cooling, devices for circulating, maintaining, and purifying the air and the water—in

 short, all the complex mechanism necessary for the comfort and convenience of the

 human cargo of the liner.

     Soon they entered the conical top compartment, a room scarcely fifteen feet in

 diameter, tapering sharply upward to a hollow point some twenty feet above them. The

 true shape of the room, however, was not immediately apparent, because of the

 enormous latticed beams and girders which braced the walls in every direction. The air

 glowed with the violet light of the twelve great ultra-light projectors, like searchlights with

 three-foot lenses, which lined the wall. The floor beneath their feet was not a level steel

 platform, but seemed to be composed of many lenticular sections of dull blue alloy.

     "We are standing upon the upper lookout lenses, aren't we ?" asked the girl. "Is

 that perfectly all x ?"

     "Sure. They're so hard that nothing can scratch them, and of course Roeser's

 Rays go right through our bodies, or any ordinary substance, like a bullet through a hole

 in a Swiss cheese. Even those lenses wouldn't refract 'em if they weren't solid fields of

 force."

     As he spoke one of the ultra-lights flashed around in a short, quick arc, and the

 girl saw that instead of the fierce glare she had expected, it emitted only a soft violet

 light. Nevertheless she dodged involuntarily and Stevens touched her arm reassuringly.

     "All x, Miss Newton—they're harmless like mice. They hardly ever have to swing

 past the vertical, and even if one shines right through you you can look it right in the eye

 as long as you want to—it can't hurt you a bit."

     "No ultra-violet at all?"

     "None whatever. Just a color—one of the many remaining crudities of our ultra-

 light vision. A lot of good men are studying this thing of direct vision, though, and it won't

 be long until we'll have a system that will really work."

     "I think it's all perfectly wonderful!" she breathed. "Just think of traveling in

 comfort through empty space, and of actually seeing through seamless steel walls,

 without even a sign of a window! How can such things be possible ?"

     "I'll have to go pretty well back," he warned, "and any adequate explanation is

 bound to be fairly deep wading in spots. How technical can you stand it ?"

     "I can go down with you middling deep—I took a lot of general science, and

 physics through advanced mechanics. Of course I didn't get into any such highly

 specialized stuff as sub-electronics or Roeser's Rays, but if you start drowning me I'll

 stop you."

     "Fine—with that to go on you can get the idea all x. Let's sit down on this girder.

 Roeser didn't do it all, by any means, even though he got popular credit for it—he

 merely helped the Martians do it. The whole thing started, of course, when the first

 space-rocket hit the moon. It was intensified when Roeser—working up, or rather down,

 from radar—so perfected his system that signals were exchanged with Mars; signals

 that neither side could develop into intelligible communication.

     "The rocketeers made bigger and better rockets until they finally built one that

 could land people safely upon Mars. Roeser, who was a mighty keen bird, was one of

 the first voyagers, and he didn't come back. He stayed there, living in a space-suit for

 five years, and got a brand-new education. Martian science always was hot, you know,

 but they were impractical. They were desperately hard up for water and air, and while

 they had a lot of wonderful ideas and theories, they couldn't overcome the practical

 technical and technological difficulties in the way of making their ideas work. Now

 putting other peoples' ideas to work was Roeser's long suit—don't think that I'm belittling

 Roeser at all, either, for he was a brave and far-sighted man, was no mean scientist,

 and was certainly one of the best organizers and synchronizers the world has ever

 known—and since Martian and Tellurian science complemented each other, so that one

 filled in the gaps of the other, it wasn't long until fleets of space-freighters were bringing

 in air and water from Venus, which had plenty of both to spare.

     "Having done all he could for the Martians and having learned most of the stuff

 he wanted to know, Roeser came back to Tellus and organized Inter-Planetary, with

 scientists and engineers on all three planets, and%set to work to improve the whole

 system, for the vessels they used then were dangerous — regular mankillers, in fact. At

 about this same time Roeser and the Inter-Planetary Corporation, with their really

 effective atomic bombs, had a big part in the unification of the world into one nation, so

 that wars could no longer interfere with progress.

     "With this introduction I can get down to fundamentals. Molecules are particles of

 the first order, and vibrations of the first order include sound, light, heat, electricity,

 radio, and so on. Second order, atoms—extremely short vibrations, such as hard X-

 rays. Third order, electrons, protons, and so on, with their accompanying Millikan, or

 Cosmic Rays. Fourth order, sub-electrons and sub-protons. These, in the material

 aspect, are supposed to be the particles of the fourth order, and in the energy aspect

 they are known as Roeser's Rays. That is, these fourth-order rays and particles seem to

 partake of the nature of both energy and matter. Following me?"

     "Right behind you," she assured him. She had been listening intently, her wide-

 spaced brown eyes fastened upon his face.

     "Since these Roeser's Rays, or particles or rays of the fourth order, seem to be

 both matter and energy, and since the rays can be converted into what is supposed to

 be the particles, they have been thought to be the things from which both electrons and

 protons were built. Therefore, everybody except Norman Brandon has supposed them

 the ultimate units of creation, so that it would be useless to try to go any further . . ."

     "Why, we were taught that they are the ultimate units!" she protested.

     "I know you were—but we really don't know anything, except what we have

 learned empirically, even about our driving forces. What is called the fourth-order

 particle is absolutely unknown, since nobody has been able to detect it, to say nothing

 of determining its velocity or other properties. It has been assumed to have the velocity

 of light only because that hypothesis does not conflict with observational data. I'm going

 to give you the generally-accepted idea, since we have nothing definite to offer in its

 place, but I warn you that that idea is very probably wrong. There's a lot of deep stuff

 down there that hasn't been dug up yet. In fact, Brandon thinks that the product of

 conversion isn't what we think it is, at all—that the actual fundamental unit and the

 primary mechanism of the transformation lie somewhere below the fourth order, and

 possibly even below the level of the ether—but we haven't been able to find a point of

 attack yet that will let us get in anywhere. However, I'm getting 'way ahead of our

 subject. To get back to it, energy can be converted into something that acts like matter

 through Roeser's Rays, and that is the empirical fact underlying the drive of our space-

 ships, as well as that of almost all other vehicles on all three planets. Power is

 generated by the great waterfalls of Tellus and Venus — water's mighty scarce on Mars,

 of course, so most of our plants there use atomics—and is transmitted on tight beams

 by means of powerful fields of force to the receptors, wherever they may be. The

 individual transmitting fields and receptors are simply matched-frequency units, each

 matching the electrical characteristics of some particular and unique beam of force. This

 beam is composed of Roeser's Rays, in their energy aspect. It took a long time to work

 out this tight-beam transmission of power, but it was fairly simple after they got it."

     He took out a voluminous notebook, at the sight of which Nadia smiled.

     "A computer might forget to dress, but you'd never catch one without a full

 magazine pencil and a lot of blank paper," he grinned in reply and went on, writing as he

 talked.

     "For any given frequency, , and phase angle, theta, you integrate, between

 limits zero and pi over two, sine theta d. . ."

     "Hold it — I'm sinking!" Nadia exclaimed. "I don't integrate at all unless it is

 absolutely necessary. As long as you stick to general science I'm right on your heels,

 but please lay off of integrations and all that—most especially lay off of those terrible

 electrical integrals. I always did think that they were the most poisonous kind known. I

 want only a general idea—that's all that I can understand, anyway."

     "Sure. I forgot—guess I was getting in deeper than is necessary, especially since

 this whole thing of beam transmission is pretty crude yet and is bound to change a lot

 before long. There is so much loss that when we get more than a few hundred million

 kilometers away from a power-plant we lose reception entirely. But to get going again,

 the receptors receive the beam and from them the power is sent to the accumulators,

 where it is stored. These accumulators are an outgrowth of the storage battery. The

 theory of the accumulator is . . ."

     "Lay off of the theory, please!" the listener interrupted. "I understand perfectly

 without it. Energy is stored in the accumulators—you put it in and take it out. That's all

 that is necessary."

     "I'd like to give you some of the theory—but, after all, it wouldn't add much to

 your understanding of the working of things, and it might mix you up, as some of it is

 pretty deep stuff. Then, too, it would take a lot of time, and the rest of your friends would

 squawk if I kept you here indefinitely. From the accumulators, then, the power is fed to

 the converters, each of which is backed by a projector. The converters simply change

 the aspect of the rays, from the energy aspect to the material aspect. As soon as this is

 done, the highly-charged particles — or whatever they are — thus formed are repelled

 by the terrific stationary force maintained in the projector backing the converter. Each

 particle departs with a velocity supposed to be that of light, and the recoil upon the

 projector drives the vessel, or car, or whatever it is attached to. Still with me?"

     "Struggling a little, but my nose is still above the surface. These particles, being

 so infinitesimally small that they cannot even be detected, go right through any

 substance without any effect—they are not even harmful."

     "Exactly. Now we are in position to go ahead with the lights, detectors, and so on.

 The energy aspect of the rays you can best understand as simply a vibration in the

 ether— an extremely short one. While not rigidly scientific, that is close enough for you

 and me. Nobody knows what the stuff really is, and it cannot be explained nor

 demonstrated by any model or concept in three-dimensional space. Its physical-

 mathematical interpretation, the only way in which it can be grasped at all, requires

 sixteen co-ordinates in four dimensions, and I don't suppose you'd care to go into that?"

     "I'll say I wouldn't!" she exclaimed, feelingly.

     "Well, anyway, by the use of suitable fields of force it can be used as a carrier

 wave. Most of this stuff of the fields of force—how to carry the modulation up and down

 through all the frequency changes necessary—was figured out by the Martians ages

 ago. Used as a pure carrier wave, with a sender and a receiver at each end, it isn't so

 bad— that's why our communicator and radio systems work as well as they do. They

 are pretty good, really, but the ultralight vision system is something else again. Sending

 the heterodyned wave through steel is easy, but breaking it up, so as to view an object

 and return the impulses, was an awful job and one that isn't half done yet. We see

 things, after a fashion and at a distance of a few kilometers, by sending an almost

 parallel wave from a twin-projector to disintegrate and double back the viewing wave.

 That's the way the lookout plates and lenses work, all over the ship— from the master-

 screens in the control room to the plates of the staterooms and lifeboats and the

 viewing-areas of the promenades. But the whole system is a make-shift, and . . ."

     "Just a minute!" exclaimed the girl. "I and everybody else have been thinking that

 everything is absolutely perfect; and yet every single thing you have talked about, you

 have ended up by describing as 'unknown', 'rudimentary', 'temporary', or a 'makeshift'.

 You speak as though the entire system were a poor thing that will have to do until

 something better has been found, and that nobody knows anything about anything! How

 do you get that way?"

     "By working with Brandon and Westfall. Those birds have got real brains and

 they're on the track of something that will, in all probability, be as far ahead of Roeser's

 Rays as Our present system is ahead of the science of the seventeenth century."

     "Really ?" she looked at him in astonishment. "Tell me about it."

     "Can't be done," he refused. "I don't know much about it—even they didn't know

 any too much about some of it when I had to come in. And what little I do know I can't

 tell, because it isn't mine."

     "But you're working with them, aren't you?"

     "Yes, in the sense that a small boy helps his father run a lathe—they're the

 brains."

     Nadia, disbelieving completely his disclaimer but secretly pleased by his attitude,

 replied:

     "You would say something like that, of course . . . where do we go from here?"

     "Down the lining of the hull, outside the passengers' quarters, to the upper

 dirigible projectors," and he led the way down a series of steep steel stairways, through

 bulkheads and partitions of steel. "One thing I forgot to tell you about—the detectors.

 They're an outgrowth of radar—reflection, you know. Whenever one spots anything it

 swings a light on it—that's what happened when that light swung toward us, up there in

 the prow—and automatic calculating machines compute and announce direction,

 distance, relative course, and so on."

     "Are there any of those lifeboats, that I have been hearing so much about, near

 here?"

     "Lots of 'em—here's one right here." He opened an insulated door, snapped on a

 light, and waved his hand. "You can't see much of it from here, but it's a complete

 spaceship in itself, capable of maintaining a dozen or fifteen persons during a two-

 weeks' cruise in space."

     "Why isn't it a good idea to retain them? Accidents are still possible, are they

 not?"

     "Of course, and there is no question of doing away with them entirely. Modern

 ships, however, have only enough of them to take care of the largest number of persons

 ever to be carried by the vessel."

     "Has the Arcturus more than she needs ?"

     "I'll say she has, and more of everything else, except room for pay-load."

     "I've heard them talking about junking her. I think it's a shame."

     "So do I, in a way—you see, I helped design her and her sister-ship, the Sirius,

 which Brandon and Westfall are using as a floating laboratory. But times change, and

 the inefficient must go. She's a good old tub, but she was built when everybody was

 afraid of space, and we had to put every safety factor into her that we could think of. As

 a result, she is four times as heavy as she should be, and that takes a lot of extra

 power. Her skin is too thick. She has too many batteries of accumulators, too many life-

 boats, too many bulkheads and airbreaks, too many and too much of everything. She is

 so built that if she should break up out in space, nobody would die if they lived through

 the shock—there are so many bulkheads, airbreaks, and lifeboats that no matter how

 many pieces she broke up into, the survivors would find themselves in something able

 to navigate. That excessive construction is no longer necessary. Modern ships carry ten

 times the pay-load on one-quarter of the power that this old battle-wagon uses. Even

 though she's only four years old, she's a relic of the days when we used to slam through

 on the ecliptic route, right through all the meteoric stuff that is always there—trusting to

 heavy armor to ward off anything too small for the observers and detectors to locate.

 Now, with the observatories and check-stations out in space, fairly light armor is

 sufficient, as we route ourselves well away from the ecliptic and so miss all the heavy

 stuff. So, bad as I hate to see her go there, the old heap is bound for the junk-yard."

     A few more flights brought them to the upper band of dirigible projectors, which

 encircled the hull outside the passengers' quarters, some sixty feet below the prow.

 They were heavy, search-light-like affairs mounted upon massive universal bearings,

 free to turn in any direction, each having its converter nestling inside its prodigious field

 of force. Stevens explained that these projectors were used in turning the vessel and in

 dodging meteorites when necessary, and .they went on through another almost invisible

 door into a hall and took an elevator down to the main corridor.

     "Well, you've seen it, Miss Newton," Stevens said regretfully, as he led her

 toward the captain's office. "The lower half is full of heavy stuff—accumulators,

 machinery, driving projectors, and such junk, so that the center of gravity is below the

 center of action of the driving projectors. That makes stable flight possible. It's all more

 or less like what we've just seen, and I don't suppose you want to miss the

 dance—anyway, a lot of people want to dance with you."

     "Wouldn't you just as soon show me the lower half as dance?"

     "Rather, lots!"

     "So would I. I can dance any time, and I want to see everything. Let's go!"

     Down they went, past battery after battery of accumulators ; climbing over and

 around the ever-increasing numbers of huge steel girders and braces; through mazes of

 heavily insulated wiring and conduits; past mass after mass of automatic machinery

 which Stevens explained to his eager listener. They inspected one of the great driving

 projectors, which, built rigidly parallel to the axis of the ship and held immovably in place

 by enormous trusses of steel, revealed neither to the eye nor to the ear any sign of the

 terrific force it was exerting. Still lower they went, until the girl had been shown

 everything, even down to the bottom ultra-lights and stern braces.

     "Tired?" Stevens asked, as the inspection was completed.

     "Not very, it's been quite a climb, but I've had a wonderful time;"

     "So have I," he declared, positively. "I know what— we'll stop off in one of these

 stern lifeboats and make us a cup of coffee before we climb back. With me ?"

     " 'Way ahead of you!" Nadia accepted the invitation enthusiastically, and they

 made their way to the nearest of the miniature space-cruisers. Here, although no

 emergency had been encountered in all the four years of the vessel's life, they found

 everything in readiness, and the two soon had prepared and eaten a hearty luncheon.

     "Well, I can't think of any more excuses for monopolizing you, Miss Newton, so I

 suppose I'll have to take you back. Believe me, I've enjoyed this more than you can

 realize—I've . . ."

     He broke off and listened, every nerve taut. "What was that ?" he exclaimed.

     "What was what? I didn't hear anything?"

     "Something wrong somewhere! I felt a vibration, and anything that'd make this

 hunk of steel even quiver must have given us one God-awful nudge. There's another!"

     The girl, painfully tense, felt only a barely perceptible tremor, but the computer,

 knowing far better than she the inconceivable strength and mass of that enormous

 structure of solidly braced hardened alloy, sprang into action. Leaping to the small

 dirigible look-out plate, he turned on the power and swung it upward.

     "Great suffering snakes!" he ejaculated, then stood mute, for the plate revealed a

 terrible sight. The entire nose of the gigantic craft had been sheared off in two immense

 slices as though clipped off by a gigantic sword, and even as they stared, fascinated, at

 the sight, the severed slices were drifting slowly away. Swinging the view along the

 plane of cleavage, Stevens made out a relatively tiny ball of metal, only fifty feet or so in

 diameter, at a distance of perhaps a mile. From this ball there shot a blinding plane of

 light, and the Arcturus fell apart at the midsection, the lower half separating clean from

 the upper portion, which held the passengers. Leaving the upper half intact, the attacker

 began slicing the lower, driving half into thin, disk-shaped sections. As that

 incandescent plane of destruction made its first flashing cut through the body of the

 Arcturus, accompanied by an additional pyrotechnic display of severed and short-

 circuited high-tension leads, Stevens and Nadia suddenly found themselves floating

 weightless in the air of the room. Still gripping the controls of the lookout plate, Stevens

 caught the white-faced girl with one hand, drew her down beside him, and held her

 motionless while his keen mind flashed over all the possibilities of the situation and

 planned his course of action.

     "They're apparently slicing us pretty evenly, and by the looks of things one cut is

 coming right about here," he explained rapidly, as he found a flashlight and drew his

 companion through the door and along a narrow passage. Soon he opened another

 door and led her into a tiny compartment so low that they could not stand upright—a

 mere cubicle of steel. Carefully closing the door, he fingered dials upon each of the

 walls of the cell, then folded himself up into a comfortable position, instructed Nadia to

 do the same, and snapped off the light.

     "Please leave it on," the shaken girl asked. "It's so ghastly!"

     "We'd better save it, Nadia," he advised, pressing her arm reassuringly. "It's the

 only light we've got, and we may need it worse later on—its life is limited, you know."

     "Later on? Do you think we'll need anything— later on?"

     "Sure! Snap out of it, ace! Of course they may get us, but this little tertiary air-

 break is a mighty small target for them to hit. And if they miss us, as I think they will,

 there's a larger room opening off each wall of this one—at least one of which will

 certainly be left intact. From any one of those rooms we can reach a life-boat. Of

 course, it's a little too much to expect that any one of the lifeboats will be left whole, but

 they're bulkheaded, too, you know, so that we can be sure of finding something able to

 navigate—providing we can make our get-away. I'm mighty glad we're aboard the old

 Arcturus right now, with all her safety-devices, instead of on one of the modern liners.

 We'd be sunk right."

     "I felt sunk enough for a minute—I'm feeling better now, though, since you are

 taking it so calmly."

     "Sure—why not? A guy's not dead until his heart stops beating, you know—our

 turn'll come next, when they let up a little."

     "But suppose they change the width of their slices, and hit this cubby, small as it

 is?"

     "It'd be just too bad," he shrugged. "In that case, we'd never know what hit us, so

 it's no good worrying about it. But say, we might do something at that, if they didn't hit

 us square. I can move fairly fast, and might be able to get a door open before the loss of

 pressure seals it. We'll light the flash . . . here, you hold it, so that I can have both hands

 free. Put both arms around me, just under the arms, and stick to me like a porous

 plaster, because if I have to move at all I'll have to jump like chain lightning. Shine the

 beam right over there, so it'll reflect and light up all the dials at once. There . . . hold on

 tight! Here they come!"

     As he spoke, a jarring shudder shook one side of their hiding-place, then, a

 moment later, the phenomenon was repeated, but with much less force, upon the other

 side. Stevens sighed with relief, took the light, and extinguished it.

     "Missed us clean!" he exulted. "Now, if they don't find us, we're all set."

     "How can they possibly find us? I seem to be always worried about the wrong

 things, but I should think that their finding us would be the least of our troubles."

     "Don't judge their vision system by ours—they've got everything, apparently.

 However, their apparatus may not be delicate enough to spot us in a space this small

 when their projectors flash through it, as they probably will. Then, too, there's a couple

 of other big items in our favor— nobody else is in the entire lower half, since all this

 machinery down here is either automatic or else controlled from up above, so they won't

 be expecting to see anybody when they get down this far; and we aren't at all

 conspicuous.

     We're both dressed in gray—your clothes in particular are almost exactly the

 color of this armor-plate—so altogether we stand a good chance of being missed."

     "What shall we do now?"

     "Nothing whatever—wish we could sleep for a couple of hours, but of course

 there's no hope of that. Stretch out here, like that—you can't rest folded up like an

 accordion— and I'll lie down diagonally across the room. There's just room for me that

 way. That's one advantage of weightlessness—you can lie down standing on your head,

 and go to sleep and like it. But I forgot—you've never been weightless before, have you

 ? Does that continuous-fall sensation make you sick?"

     "Not so much, now, except that I feel awfully weird inside. I was horribly dizzy

 and nauseated at first, but it's going away."

     "That's good—it makes lots of people pretty sick. In fact, some folks get awfully

 sick and can't seem to get used to it at all. It's the canals in the inner ear that do most of

 it, you know. However, if you're as well as that already, you'll be a regular spacehound

 in half an hour. I've been weightless for weeks at a stretch, out in the Sirius, and now

 I've got so I really like it. Here, we'd better keep in touch." He found her hand and

 tucked it under his arm. "Stabilize our positions more, besides keeping us from getting

 too lonesome, here in the dark," he concluded, in a matter-of-fact voice.

     "Thanks for saying 'us' — but you would, wouldn't you?" and a wave of

 admiration went through her for the real and chivalrous manhood of the man with whom

 she had been forced by circumstances to cast her lot. "How long must we stay here?"

     "As long as the air lasts, and I'd like to stay here longer than that. We don't want

 to move around any more than we absolutely have to until their rays are off of us, and

 we have no way of knowing how long that'll be. Also, we'd better keep still. I don't know

 what kind of an audio system they've got, but there's no use taking unnecessary

 chances."

     "All x—I'm an oyster's little sister," and for many minutes the two remained

 motionless and silent. Now and then Nadia twitched and started at some vague real or

 imaginary sound—now and then her fingers tightened upon his biceps—and he pressed

 her hand with his arm in reassurance and understanding. Once a wall of their cell

 resounded under the impact of a fierce blow and Stevens instantly threw his arm around

 the girl, twisting himself between her and the threatened wall, ready for any emergency.

 But nothing more happened, the door remained closed, the cell stayed bottle-tight, and

 time wore slowly on. All too soon the unmistakable symptoms of breathing an unfit

 atmosphere made themselves apparent and Stevens, after testing each of the doors,

 drew the girl into a larger room, where they breathed deeply of the fresh, cool air.

     "How did you know that this room was whole ?" asked Nadia. "We might have

 stepped out into space, mightn't we?"

     "No; if this room had lost its tightness the door wouldn't have opened. They won't

 open if there's a difference of one kilogram pressure on the two sides. That's how I

 knew that the room we were in at first was cut in two— the door into that air-break

 wouldn't move."

     "What comes next?"

     "I don't know exactly what to do—we'd better hold a little council of war. They

 may have gone . . ." Stevens broke off as the structure began to move, and they settled

 down upon what had been one of the side-walls. Greater and greater became the

 acceleration, until their apparent weight was almost as much as it would have been

 upon the Earth, at which point it became constant. ". . . but they haven't," he continued

 the interrupted sentence. "This seems to be a capture and seizure, as well as an attack,

 so we'll have to take the risk of looking at them. Besides, it's getting cold in here. One or

 two of the adjoining cells have apparently been ruptured and we're radiating our heat

 out into space, so we'll have to get into a lifeboat or freeze. I'll go pick out the best one.

 Wonder if I'd better take you with me, or hide you and come back after you ?"

     "Don't worry about that—I'm coming with you," Nadia declared, positively.

     "Just as well, probably," he assented, and they set out. A thorough exploration of

 all the tight connecting cells revealed that not a lifeboat within their reach remained

 intact, but that habitable and navigable portions of three such craft were available.

 Selecting the most completely equipped of these, they took up their residence therein

 by entering it and closing the massive insulating door. Stevens disconnected all the

 lights save one, and so shielded that one before turning it on that it merely lightened the

 utter darkness into a semi-permeable gloom. He then stepped up to the lookout plate,

 and with his hand upon the control, pondered long the possible consequences of what

 he wished to do.

     "What harm would it do to take just a little peek?"

     "I don't know—that's the dickens of it. Maybe none, and then again, maybe a lot.

 You see, we don't know who or what we are up against. The only thing we know is that

 they've got us beat a hundred ways, and we've got to act accordingly. We've got to

 chance it sometime, though, if we ever get away, so we might as well do it now. I'll put it

 on very short range first, and see what we can see. By the small number of cells we've

 got here I'm afraid they've split us up lengthwise, too—so that instead of having a whole

 slice of the old watermelon to live in, we've got only about a sixth of one—shaped about

 like a piece of restaurant pie. One thing I can do, though. I'll turn on the communicator

 receiver and put it on full coverage—maybe we can hear something useful."

     Putting a little power upon the visiray plate, he moved the point of projection a

 short distance from their hiding-place, so that the plate showed a view of the wreckage.

 The upper half of the vessel was still intact, the lower half a jumble of sharply-cut

 fragments. From each of the larger pieces a brilliant ray of tangible force stretched

 outward.

     Suddenly their receiver sounded behind them, as the high-powered transmitter in

 the telegraph room tried to notify headquarters of their plight.

     "Arcturus attacked and cut up being taken tow . . ."

     Rapidly as the message was uttered the transmitter died with a rattle in the

 middle of a word, and Nadia looked at Stevens with foreboding in her eyes.

     "They've got something, that's one thing sure, to be able to neutralize our

 communicator beams that way," he admitted. "Not so good—we'll have to play this dose

 to our vests, girl!"

     "Are you just trying to cheer me up, or do you really think we have a chance?"

 she demanded. "I want to know just where we stand."

     "I'm coming clean with you, no kidding. If we can get away", we'll be all x,

 because I'll bet a farm that by this time Brandon's got everything those birds have, and

 maybe more. They beat us to it, that's all. I'm kind of afraid, though, that getting away

 isn't going to be quite as simple as shooting fish down a well."

     Far ahead of them a port opened, a lifeboat shot out at its full power, and again

 their receiver tried to burst into sound, but it was a vain attempt. The sound died before

 one complete word could be uttered, and the lifeboat, its power completely neutralized

 by the rays of the tiny craft of the enemy, floated gently back toward the mass of its

 parent and accompanied it in its headlong flight. Several more lifeboats made the

 attempt, as the courageous officers of the Arcturus, some of whom had apparently

 succeeded in eluding the vigilance of the captors, launched the little shells from various

 ports; but as each boat issued its power was neutralized and it found itself dragged

 helplessly along in the grip of one of those mysterious, brilliant rays of force. At least

 one hidden officer must have been watching the fruitless efforts, for the next lifeboat to

 issue made no attempt, either to talk or to flee, but from it there flamed out into space a

 concentrated beam of destruction—the terrible ray of annihilation, against which no

 known substance could endure for a moment; the ray which had definitely outlawed

 war. But even that frightful weapon was useless— it spent its force harmlessly upon an

 impalpable, invisible barrier, a hundred yards from its source, and the bold lifeboat

 disappeared in one blinding explosion of incandescence as the captor showed its real

 power in retaliation. Stevens, jaw hard-set, leaped away from the screen, then brought

 himself up so quickly that he skated across the smooth steel floor. Shutting off the

 lookout plate, he led the half-fainting girl across the room to a comfortable seat and sat

 down beside her—raging, but thoughtful. Nadia soon recovered.

     "Why are you acting so contrary to your nature—is it because of me?" she

 demanded. "A dozen times I've seen you start to do something and then change your

 mind. I will not be a load on you nor hinder you in anything you want to do."

     "I told your father I'd look after you, and I'm going to do it," he replied, indirectly. "I

 would do it anyway, of •course—even if you are ten or twelve years older than I thought

 you were."

     "Yes, Dad never has realized that I'm more than eight years old. I see—you were

 going out there and be slaughtered?" He flushed, but made no reply. "In that case I'm

 glad I'm here—that would have been silly. I think we'd better hold that council of war you

 mentioned a while ago, don't you?"

     "All x. I need a smoke—do you indulge?"

     "No, thanks. I tried it a few times at school, but never liked it."

     He searched his pockets, bringing to light an unopened package and a battered

 remnant which proved to contain one delapidated cigarette. He studied it thoughtfully.

 "I'll smoke this wreck," he decided, "while it's still smokable. We'll save the rest of

 them—I'm afraid it'll be a long time between smokes. Well, let's confer!"

     "This will have to be a one-sided conference, since I don't imagine that any of my

 ideas will prove particularly helpful. You talk and I'll listen."

     "You can't tell what ideas may be useful—chip in any time you feel the urge.

 Here's the dope as I see it. They're highly intelligent creatures and are in all probability

 neither Martians nor Venerians, since if any of them had any such stuff as that some of

 us would have known about it, and besides, I don't believe they would have used it in

 just that way. Mercury is not habitable, at least for organic beings; and we have never

 seen any sign of any other kind of inhabitants who could work with metals and rays.

 They're probably from Jupiter, although possibly from further away. I say Jupiter

 because I would think, from the small size of the ship, that it may be still in the

 experimental stage, so that they probably didn't come from any further away than

 Jupiter. Then, too, if they'd been very numerous, somebody would have sighted one

 before. I'd give my left leg and four fingers for one good look at the inside of that ship."

     "Why didn't you take it, then ? You never even looked toward it, after that one

 first glimpse."

     "I'll say I didn't—the reason being that they may have automatic detectors, and

 as I have suggested before, our system "of vision is so crude that its use could be

 detected with a clothesline or a basket full of scrap iron. But to resume. Their aim is to

 capture, not destroy, since they haven't killed anybody except the one crew that

 attacked them. Apparently they want to study us or something. However, they don't

 intend that any of us shall get away, nor even send out a word of what has happened to

 us. Therefore it looks as though our best bet is to hide now, and try to sneak away on

 them after a while—direct methods won't work. Right?"

     "You sound lucid. Is there any possibility of getting back, though, if we got

 anywhere near Jupiter? It's so far away!"

     "It's a long stretch, no fooling, from Jupiter to any of the planets where we have

 power-plants—particularly now, when Mars and Tellus are subtending an angle of

 something more then ninety degrees at the sun, and Venus is between the two, while

 Jupiter is clear across the sun from all three of them. Even when Jupiter is in mean

 opposition to Mars, it is still some five hundred and fifty million kilometers away, so you

 can form some idea as to how far it is from our nearest plant now. No, if we expect to

 get back under our own power, we've got to break away pretty quick—these lifeboats

 have very little accumulator capacity, and the receptors are useless above about three

 hundred million kilometers . . ."

     "But it'll take us a long time to go that far, won't it ?" "Not very. Our own ships,

 using only the acceleration of gravity, and both plus and minus at that, make the better

 than four hundred million kilometers of the long route to Mars in five days. These birds

 are using almost that much acceleration, and I don't see how they do it. They must have

 a tractor ray. Brandon claimed that such a thing was theoretically possible, but Westfall

 and I couldn't see it. We ragged him about it a lot—and he was right. I thought of course

 they'd drift with us, but they are using power steadily. They've got some system!"

     "Suppose they could be using intra-atomic energy ?" "Could be." The man

 frowned in concentration. "Piles as we know them can't be that small and portable,

 because of the shielding necessary . . . but Brandon and Westfall have been doing a lot

 of arguing . . . anyway, I don't see that it makes any difference to us. We'll just have to

 admit that they've got a better power system than we have—as of now. Well, maybe

 we've given them time enough to get over being suspicious; let's see if we can sneak

 away from them."

     By short and infrequent applications of power to the dirigible projectors of the life-

 boat, Stevens slowly shifted the position of the fragment which bore their craft until it

 was well clear of the other components of the mass of wreckage. He then exerted a

 very small retarding force, so that their bit would lag behind the procession, as though it

 had accidentally been separated. But the crew of the captor were alert, and no sooner

 did a clear space show itself between them and the mass than a ray picked them up

 and herded them back into place. Stevens then nudged other pieces so that they fell

 out, only to see them also rounded up. For hour after hour he kept trying—doing nothing

 sufficiently energetic to create any suspicion, but attempting everything he could think of

 that offered any chance of escape from the clutches of their captors. Immovable at the

 plate, his hands upon the controls, he performed every insidious maneuver his agile

 brain could devise, but he could not succeed in separating their vehicle from its fellows.

 Finally, after a last attempt which was foiled as easily as its predecessors, he shut off

 his controls and turned to his companion with a grin.

     "I didn't think I could get away with it—they're keen, that gang—but I had to keep

 at it as long as it would have done us any good."

     "Wouldn't it do us any good now ?"

     "Not a bit—we're going so fast that we couldn't stop —we're out of even radio

 range of our closest power-plant. We'll have to put off any more attempts until they slow

 us down. Then, fairly close to at least one of the moons of Jupiter, we'll have our best

 chance—so good, in fact, that I really think we can make it."

     "But what good would that do us, if we couldn't get back?" Dire foreboding

 showed in her glorious eyes.

     "Lots of things not tried yet, girl, and we'll try 'em all. First, we get away. Second,

 we try to get in touch with Norman Brandon. . . . ."

     "How ? No known radio will carry half that far."

     "No, but I think that an as yet unknown radio may be able to—and there is a bare

 possibility that I'll be able to communicate."

     "Oh, wonderful — that lifts a frightful load off my mind," she breathed.

     "But just a minute — I said I'd come clean with you, and I will. The odds are all

 against us, no matter what we do. If that unknown radio won't work — and it probably

 won't—there are several other things we can try, but they're all pretty slim chances.

 Even if we get away, it'll probably be about the same thing as though you were to be

 marooned on a desert island without any tools, and with your rescue depending upon

 your ability to build a high-powered radio station with which to call to a mainland for

 help. However, if we don't try to get away, our only alternative is letting them know we're

 here, and joining our friends in captivity."

     "And then what?"

     "Your guess is as good as mine. Imprisonment and restraint, certain; death,

 possible; return to Earth, almost certainly impossible—life as guests, highly improbable."

     "I'm with you, Steve, all the way."

     "Well, it's 'way past sleep-time1—we've both been awake better than fifty hours.

 I'm all in and you look like a spent force. We'll get us a bite of supper and turn in."

     An appetizing supper was prepared from the abundant stores and each ate a

 heartier meal than either would have believed possible. Stevens considered his

 unopened package of cigarettes, then regretfully put it back into his pocket still

 unopened and turned to Nadia.

     "You might as well sleep here, and I'll go in there. If anything scares you, yell.

 Good-night, little fellow."

     "Wait a minute, Steve." Nadia flushed, and her brown eyes and black eyebrows,

 in comparison with her golden-blonde hair, lent her face a quizzical, elfin expression

 that far belied her feelings as she stared straight into his eyes. "I've never even been

 away from the Earth before, and with all this happening, I'm simply scared to death. I've

 been trying to hide it, but I couldn't stand it alone, and we're going to be together too

 long and too close for senseless conventions to affect us. There's two bunks over there,

 close together—why don't you sleep in one of them ?"

     He returned her steadfast gaze for a moment in silence.

     "All x with me," he answered, keeping out of his voice all signs of the tenderness

 he felt for her, and of his very real admiration for her straightforward conduct in a

 terrifying situation. "You trust me, then?"

     "Trust you! Don't be silly—I know you! I know you, and I know Brandon and

 Westfall—I know what you've done, and exactly the kind of men you are. Trust you?

 Don't be a sap!"

     "Thanks, Nadia," and promises were made and received in a clasp from which

 Nadia's right hand, strong as it was, emerged slightly damaged.

     "By the way, what is your first name, fellow-traveler ?" she asked in lighter vein.

 "Nobody, not even Dad or Breckie, ever seems to call you anything but 'Steve' when

 they talk about you." She was amazed at the effect of her innocent question,-for

 Stevens flushed to his hair and spluttered.

     "It's Percy!" he snorted. "Percival Van Schravendyck Stevens. Wouldn't that tear

 it?"

     "Why, I think Percival's a real nice name!"

     "Silence!" he hissed in burlesque style. "Young woman, I have revealed to you a

 secret known to but few living creatures. On your very life, keep it inviolate!"

     "Oh, very well, if you insist. Good-night. . . . . Steve!" and she gave him a radiant

 and honest smile; the first smile he had seen since the moment of the attack.
 CHAPTER 3

Castaways Upon Ganymede

 Upon awakening, the man's first care was to instruct the girl in the operation of the

 projectors, so that she could keep the heavily-armored edge of their small section,

 which she had promptly christened The Forlorn Hope, between them and the grinding,

 clashing mass of wreckage, and thus protect the relatively frail inner portions of their

 craft from damage.

     "Keep an eye on things for a while, Nadia," he instructed, as soon as she could

 handle the controls, "and don't use any more power than is absolutely necessary. We'll

 need it all, and besides, they can probably detect anything we can use. There's

 probably enough leakage from the ruptured accumulator cells to mask quite a little

 emission, but don't use much. I'm going to see what I can do about making this whole

 wedge navigable."

     "Why not just launch what's left of this lifeboat? It's space-worthy, isn't it ?"

     "Yes, but it's too small. Two or three of the big dirigible projectors of the lower

 band are on the rim of this piece-of-pie-shaped section we're riding, I think. If so, and if

 enough batteries of accumulators are left intact to give them anywhere nearly full power,

 we can get an acceleration that will make a lifeboat look sick. Those main dirigibles, you

 know, are able to swing the whole mass of the Arcturus, and what they'll do to this one

 chunk of it—we've got only a few thousand tons of mass in this piece—will be

 something pretty. Also, having the metal may save us months of time in mining it."

     He found the projectors, repaired or cut out the damaged accumulator cells, and

 reconnected them through the controls of the lifeboat. He moved into the "engine-room"

 the airtanks, stores, and equipment from all the other fragments which, by means of a

 space-suit, he could reach without too much difficulty. He helped himself to banks of

 accumulator cells from the enormous driving batteries of the ill-fated Arcturus, bolting

 them down and connecting them solidly until almost every compartment of their craft

 was one mass of stored-up energy.

     Days fled like hours, so furiously busy were they in preparing their peculiar

 vessel for a cruise of indefinite duration. Stevens cut himself short on sleep and

 snatched his meals in passing; and Nadia, when not busy at her own tasks of

 observing, housekeeping, and doing what little piloting was required, was rapidly

 learning to wield effectively the spanner and pliers of the mechanic and electrician.

     "I'm afraid our time is getting short, Steve," she announced after making an

 observation. "It looks as though we're getting there—wherever it is we're going."

     "Well, I've got only two more jobs to do, but they're the hardest of the lot. Is it

 Jupiter, or can't you tell yet?"

     "It looks more like Jupiter than any of the satellites, I think. Here's the observation

 you told me to take."

     "Looks like Jupiter," he agreed, after he had rapidly checked her figures. "We'll

 pass very close to one of those two satellites—probably Ganymede—which is fine for

 our scheme. All four of the major satellites have water and atmosphere, but Ganymede,

 being largest, is best for our purposes. We've got a couple of days yet—just about time

 to finish up. Let's get going—you know what to do."

     "Steve, I'm afraid of it. It's too dangerous—isn't there some other way?"

     "None that I can see. The close watch they're keeping on every bit of this junk

 makes it our only chance for a getaway. I'm pretty sure I can do it—but if I should

 happen to get nipped, just use enough power to let them know you're here, and you

 won't be any worse off than if I hadn't tried to pull off this stunt."

     He donned a space-suit, filled a looped belt with tools, picked up a portable

 power-drill, and stepped into the tiny airlock. Nadia deftly guided their segment against

 one of the larger fragments and held it there with a gentle, steady pressure, while

 Stevens, a light cable paying out behind him, clambered carefully over the wreckage,

 brought his drill into play, and disappeared inside the huge wedge. In less than an hour

 he returned without mishap and reported to the glowing girl.

     "Just like shooting fish down a well! Most of the accumulator cells were tight, and

 installing the relays wasn't a bad job at all. Believe me, girl, there'll be junk filling all the

 space between here and Saturn when we touch them off!"

     "Wonderful, Steve!" Nadia exclaimed. "It won't be so bad seeing you go into the

 others, now that you have this one all rigged up."

     Around and around the mass of wreckage they crept, and in each of the larger

 sections Stevens connected up the enormous fixed or dirigible projectors to whatever

 accumulator cells were available through sensitive relays, all of which he could close by

 means of one radio impulse. The long and dangerous task done, he stood at the lookout

 plate, studying the huge disk which had been the upper portion of the lower half of the

 Arcturus, frowning in thought. Nadia reached over his shoulder and switched off the

 plate.

     "Nix on that second job, big fellow!" she declared. "They aren't really necessary,

 and you're altogether too apt to be killed trying to get them. It's too ghastly — I won't

 stand for your trying it, so that ends it."

     "We ought to have them, really," he protested. "With those special tools, cutting

 torches, and all that stuff, we'd be sitting pretty. We'll lose weeks of time by not having

 them."

     "We'll just have to lose it, then. You can't get 'em, any more than a baby can get

 the moon, so stop crying about it," she went over the familiar argument for the twentieth

 time. "That stuff up there is all grinding together like cakes of ice in a floe; the particular

 section you want is in plain sight of whoever is on watch; and those tools and things are

 altogether too heavy to handle. You're a husky brute, I know, but even you couldn't

 begin to handle them, even if you had good going. I couldn't help you very much, even if

 you'd let me try; and the fact that you so positively refuse to let me come along shows

 how dangerous you know the attempt is bound to be. You'd probably never even get up

 there alive, to say nothing of getting back here. No, Steve, that's out like a light."

     "I sure wish they'd left us weightless for a while, sometime, if only for an hour or

 two," he mourned.

     "But they didn't!" she retorted, practically. "So we're just out of luck to that extent.

 Our time is about up, too. It's time you worked us back to the tail end of this

 procession—or rather, the head end, since we're traveling 'down' now."

     Stevens took the controls and slowly worked along the outer edge of the mass,

 down toward its extremity. Nadia put one hand upon his shoulder and he glanced

 around.

     "Thanks, Steve. We have a perfectly wonderful chance as it is, and we've gone

 so far with our scheme together that it would be a crying shame not to be able to go

 through with it. I'd hate like sin to have to surrender to them now, and that's all I could

 do if anything should become of you. Besides . . . . ." her voice died away into silence.

     "Sure, you're right," he hastily replied, dodging the implication of that unfinished

 sentence. "I couldn't figure out anything that looked particularly feasible, anyway—that's

 why I didn't try it. We'll pass it up."

     Soon they arrived at their objective and maintained a position well in the van, but

 not sufficiently far ahead of the rest to call forth a restraining ray from their captors.

 Already strongly affected by the gravitational pull of the mass of the satellite, many of

 the smaller portions of the wreck, not directly held by the tractors, began to separate

 from the main mass. As each bit left its place another beam leaped out, until it became

 apparent that no more were available, and Stevens strapped the girl and himself down

 before two lookout plates.

     "Now for it, Nadia!" he exclaimed, and simultaneously threw on the power of his

 own projectors and sent out the radio impulse which closed the relays he had so

 carefully set. They were thrown savagely against the restraining straps and held there

 by an enormous weight as the gigantic dirigible projectors shot their fragment of the

 wreck away from the comparatively slight force which had been acting upon it, but they

 braced themselves and strained their muscles in order to watch what was happening.

 As the relays in the various fragments closed, the massed power of the accumulators

 was shorted dead across the converters and projectors instead of being fed into them

 gradually through ( the controls of the pilot, with a result comparable to that of the

 explosion of an ammunition dump. Most of the masses, whose projectors were fed by

 comparatively few accumulator cells, darted away entire with a stupendous

 acceleration. A few of them, however, received the unimpeded flow of complete

 batteries. Those projectors tore loose from even their massive supports and crashed

 through anything opposing them like huge, armor-piercing projectiles. It was a spectacle

 to stagger the imagination, and Stevens grinned as he turned to the girl, who was

 staring in wide-eyed amazement.

     "Well, ace, I think they're busy enough now so that it'll be safe to take that long-

 wanted look at their controls," and he flashed the twin beams of his lookout light out

 beyond the upper half of the Arcturus — only to see them stop abruptly in mid-space.

 Even the extremely short carrier-wave of Roeser's Rays could not go through the

 invisible barrier thrown out by the tiny, but powerful globe of space.

     "No penetration?" Nadia asked.

     "Flattened 'em out cold. 'However,' as the fox once remarked about the grapes,

 'I'll bet they're sour, anyway.' We'll have some stuff of our own, one of these days. I sure

 hope the fireworks we started back there keep those birds amused until we get out of

 sight, because if I use much more power on these projectors we may not have juice

 enough left to stop with."

     "You're using enough now to suit me—I'm so heavy I can hardly lift a finger!"

     "You'd better lift 'em, ace'! You've got to watch what's going on back there while I

 navigate us around this moon."

     "All x, chief . . . They've got their hands full, apparently. Those rays are shooting

 around all over the sky. It looks as though they were trying to capture four or five things

 at once with each one."

     "Good! Tell me when the moon cuts them off."

     At the awful acceleration they were using, which constantly increased the terrific

 velocity with which they had been traveling when they made good their escape, it was

 not long until they had placed the satellite between them and the enemy; then Stevens

 cut down and reversed his power. Such was their speed, however, that a long detour

 was necessary in order to reduce it to a safe landing rate. As soon as this could be

 done Stevens headed for the morning zone and dropped the Hope rapidly toward the

 surface of that new, strange world. Details could not be distinguished at first because of

 an all-enshrouding layer of cloud, but the rising sun dispelled the mist, and when they

 had descended to within a few thousand feet of the surface their vision was

 unobstructed. Immediately below them the terrain was mountainous and heavily

 wooded; while far to the east the rays of a small, pale sun glinted upon a vast body of

 water. No signs of habitation were visible as far as the eye could reach.

     "Now to pick out a location for our power-plant. We must have a waterfall for

 power, a good place to hide our ship from observation, and I'd like to have a little seam

 of coal. We can use wood if we have to, but I think we can find some coal. This is all

 sedimentary rock—it looks a lot like the country along the North Fork of the Flathead, in

 Montana. There are a lot of coal outcrops, usually, in such topography as this is."

     "We want to hide in a hurry, though, don't we ?"

     "Not particularly, I don't think. If they had missed us at all they would have had us

 long ago, and with all the damage we did with those projectors they won't be surprised

 at one piece being missing—I imagine they lost a good many."

     "But they'll know that somebody caused all that disturbance. Won't they hunt for

 us?"

     "Maybe, and maybe not—no telling what they'll do. However, by the time they

 can land and get checked up and ready to hunt for us, we'll be a mighty small needle,

 well hidden in a good big haystack."

     For several hours they roamed over that mountainous region at high velocity,

 seeking the best possible location, and finally they found one that was almost ideal—a

 narrow canyon overhung with heavy trees, opening into a wide, deep gorge upon a level

 with its floor. A mighty waterfall cascaded into the gorge just above the canyon, and

 here and there could be seen black outcrops which Stevens, after a close scrutiny,

 declared to be coal. He deftly guided their cumbersome wedge of steel into the retreat,

 allowed it to settle gently to the ground, and shut off the power.

     "Well, little fellow-conspirator against the peace and dignity of the Jovians, we're

 here. We got away clean, and as long as we don't use any high-tension stuff or anything

 else that they can trace, I think we're as safe as money in a bank."

     "I suppose that I ought to be scared to death, Steve, but I'm not—I'm just too

 thrilled for words," Nadia answered, and the eager sparkle in her eyes bore out her

 words. "Can we go out now ? How about air ? Shall we wear suits or go out as we are ?

 Have you got a weapon of any kind ? Hurry up—let's do something!"

     "Pipe down, ace! Remember that we don't know any more about anything around

 here than a pig does about Sunday, and conduct yourself accordingly. Take it easy. I'm

 surprised at the gravity here. This is certainly Ganymede, and it has a diameter of only

 about fifty-seven hundred kilometers. If I remember correctly, Damoiseau estimated its

 mass at about three one-hundredths that of the Earth, which would make its surface

 gravity about one-sixth. However, it is actually almost a half, as you see by this spring-

 balance here. Therefore it is quite a little more massive than has been '. . . "

     "What of it ? Let's go places and do things!"

     "Calm yourself, Ginger, you've got lots of time—we'll be here for quite a while, I'm

 afraid. We can't go out until we analyze the air—we're lucky there's as much as there is.

 I'm not quite the world's foremost chemist, but fortunately an air-analysis isn't much of a

 job with the apparatus we carry."

     While Nadia controlled her impatience as best she could, Stevens manipulated

 the bulbs and pipettes of the gas apparatus.

     "Pressure, fifty-two centimeters—more than I dared hope for—and analysis all x,

 I believe. Oxygen concentration a little high, but not much."

     "We won't have to wear the space-suits, then?"

     "Not unless I missed something in the analysis. The pressure corresponds to our

 own at a height of about three thousand meters, which we can get used to without too

 much trouble. Good thing, too. I brought along all the air I could get hold of, but as I told

 you back there, if we had to depend on it altogether, we might be out of luck. I'm going

 to pump some of our air back into a cylinder to equalize our pressure—don't want to

 waste any of it until we're sure the outside air suits us without treatment."

     When the pressure inside had been gradually reduced to that outside and they

 had become accustomed to breathing the rarefied medium, Stevens opened the airlock

 and for some time cautiously sniffed the atmosphere of the satellite. He could detect

 nothing harmful or unusual in it—it was apparently the same as Earthly air—and he

 became jubilant.

     "All x, Nadia—luck is perched right on our banner. Freedom, air, water, power,

 and coal! Now as you suggested, we'll go places and do things!"

     "Suppose it's safe?" Her first eagerness to explore their surroundings, had

 abated noticeably. "You aren't armed, are you?"

     "No, and I don't believe that there was a gun of any kind aboard the Arcturus.

 That kind of thing went out quite a while ago, you know. We'll take a look, anyway—

 we've got to find out about that coal before we decide to settle down here. Remember

 this half-gravity stuff, and control your leg-muscles accordingly."

     Leaping lightly to the ground, they saw that the severed section of fifty-inch armor

 which was the rim of their conveyance almost blocked the entrance to the narrow

 canyon which they had selected for their retreat. Upon one side that wall of steel

 actually touched the almost perpendicular wall of rock; upon the other side there was

 left only a narrow passage. They stepped through it, so that they could see the waterfall

 and the gorge, and stopped, silent. The sun, now fairly high, was in no sense the

 familiar orb of day, but was a pale, insipid thing, only one-fifth the diameter of the sun to

 which they were accustomed, and which could almost be studied with the unshielded

 eye. From their feet a grassy meadow a. few hundred feet wide sloped gently down to

 the river, from whose farther bank a precipice sprang sheer upward for perhaps a

 thousand feet—merging into towering hills whose rugged grandeur was reminiscent of

 the topography of the moon. At their backs the wall of the gorge was steep, but not

 precipitous, and was covered with shrubs and trees—some of which leaned out over the

 little canyon, completely screening it, and among whose branches birds could now and

 then be seen flitting about. In that direction no mountains were visible, indicating that

 upon their side of the river there was an upland plateau or bench. To their right the river,

 the gorge, and the strip of meadow extended for a mile or more, then curved away and

 were lost to sight. To their left, almost too close for comfort, was the stupendous

 cataract, towering above them to a terror-inspiring height. Nadia studied it with awe,

 which changed to puzzled wonder.

     "What's the matter with it, Steve? It looks like a picture in slow motion, like the

 kind they take of your dives— or am I seeing things?"

     "No, it's really slow, compared to what we're used to. Remember that one-half

 gravity stuff!"

     "Oh, that's right, but it certainly does look funny. It gives me the creeps."

     "You'll get used to it pretty quick—just as you'll get used to all the rest of the

 things having only half their normal weight and falling only half as fast as they ought to

 when you drop them. Well, I don't see anything that looks dangerous yet—let's go up

 toward the falls a few meters and prospect that outcrop."

     With a few brisk strokes of an improvised shovel he cleared the outcrop of

 detritus and broke off several samples of the black substance, with which they went

 back to the Forlorn Hope.

     "All x—it's real coal," Stevens announced after a series of tests. "I've seen better,

 but on the other hand, there's lots worse. It'll make good gas, and a kind of a coke. Not

 so hot, but it'll do. Now we'd better get organized, partner, for a long campaign."

     "Go ahead and organize—I'm only the cheap help in this enterprise."

     "Cheap help! You're apt to be the life of the party. Can you make and shoot a

 bow and arrow ?"

     "I'll say I can—I've belonged to an archery club for five years."

     "What'd I tell you? You're a life saver! Here's the dope—we've got to save our

 own supplies as much as possible until we know exactly what we're up against, and to

 do that we've got to live off the country. I'll fake up something to knock over some of

 those birds and small game, then we can make real bow-strings and feathered arrows

 and I'll forge some steel arrowheads while you're making yourself a real bow. We'd

 better make me about a hundred-pound war bow, too . . ."

     "A hundred!" interrupted Nadia. "That's a lot of bow, big boy—think you can bend

 it ?"

     "You'd be surprised," he grinned. "I'm not quite like Robin Hood—I've been

 known to miss a finger-thick wand at a hundred paces—but I'm not exactly a beginner."

     "Oh, of course—I should have known by your language that you're an archer,

 otherwise you'd never have used such an old-fashioned word as 'pounds'. I shoot a

 thirty-five pound bow ordinarily, but for game I should have the heaviest one I can hold

 accurately—about a forty-five, probably."

     "All x. And as soon as I can I'll make us a couple of suits of fairly heavy steel

 armor, so that we'll have real protection if we should need it. You see; we don't know

 what we are apt to run up against out here. Then, with that much done, it'll be up to you

 to provide, since I'll have to work tooth and nail at the forges. You'll have to bring home

 the bacon, do the cooking and so on, and see what you can find along the line of edible

 roots, grains, fruits, and what-not. Sort of reverse the Indian idea—you be the hunter

 and I'll keep the home fires burning. Can do?"

     "What it takes to do that, I've got," Nadia assured him, her eyes sparkling. "Have

 you your job planned out as well and as fittingly as you have mine ?"

     "And then some. We've got just two methods of getting away from here—one is

 to get in touch with Brandon, so that he'll come after us; the other is to recharge our

 accumulators and try to make it under our own power. Either course will need power,

 and lots of it . . ."

     "I never thought of going back in the Hope. Suppose we could ?"

     "About as doubtful as the radio—I think that I could build a pair of matched-

 frequency auto-dirigible transmitter and receptor units, such as are necessary for space-

 ships fed by stationary power-plants, but after I got them built they'd take us less than

 half way there. Then we'd have only what power we can carry, and I hate even to think

 of what probably would happen to us. We'd certainly have to drift for months before we

 could get close enough to any of our plants to radio for help, and we'd be taking awful

 chances. You see, we'd have to take a very peculiar orbit, and if we should miss

 connections passing the inner planets, what the sun would do to us at the closest point

 and where what's left of us would go on the backswing would be just too bad! Besides, if

 we can get hold of the Sirius, they'll come loaded for bear, and we may be able to do

 something about the rest of the folks out here."

     "Oh!" breathed the girl. "Wouldn't it be wonderful if we could! I thought of course

 they'd all be . . ." her voice died away.

     "Not necessarily—there's always a chance. That's why I'm trying the ultra-radio

 first. However, either course will take lots of power, so the first thing I've got to do is to

 build a power plant. I'm going to run a penstock up those falls, and put in a turbine,

 driving a high-tension alternator. Then, while I'm trying to build the ultra-radio, I'll be

 charging our accumulators, so that no time will be lost in case the radio fails. If it does

 fail—and remember I'm not counting on its working—of course I'll tackle the

 transmission and receptor units before we start out to drift it."

     "You say it easy, Steve, but how can you build all those things, with nothing to

 work with ?"

     "It's going to be a real job—I'll not try to kid you into thinking it'll be either easy or

 quick. Here's the way everything will go. Before I can even lay the first length of the

 penstock, I've got to have the pipe—to make which I've got to have flat steel—to get

 which I'll have to cut some of the partitions out of this ship of ours—to do which I'll have

 to have a cutting torch — to make which I'll have to forge nozzles out of block metal and

 to run which I'll have to have gas—to get which I'll have to mine coal and build a gas-

 plant—to do which . . ."

     "Good heavens, Steve, are you going back to the Stone Age? I never thought of

 half those things. Why, it's impossible !"

     "Not quite, guy. Things could be a lot worse—that's why I brought along the

 whole Forlorn Hope, instead of just the lifeboat. As it is we've got several thousand tons

 of spare steel and lots of copper. We've got ordinary tools and a few light motors,

 blowers, and such stuff. That gives me a great big start — I won't have to mine the ores

 and smelt the metals, as would have been necessary otherwise. However, it'll be plenty

 bad. I'll have to start out in a pretty crude fashion, and for some of the stuff I'll need I'll

 have to make, not only the machine that makes the part I want, but also the machine

 that makes the machine that makes the machine that makes it—and so on, just how far

 down the line I haven't dared to think."

     "You must be a regular jack-of-all-trades, to think you can get away with such a

 program as that?"

     "I am; nothing else but. You see, while most of my school training was in

 advanced physics and mathematics, I worked my way through by computing and

 designing, and I've done a lot of truck-horse labor of various kinds, besides. I can

 calculate and design almost anything, and I can make a pretty good stab at translating a

 design into fabricated material. I wouldn't wonder if Brandon's ultra-radio would stop me,

 since nobody had even started to build one when I saw him last—but I helped compute

 it, know the forces involved as well as he did at that time, and it so happens that I know

 more about the design of coils and fields of force than I do about anything else. So I

 may be able to work it out eventually. It isn't going to be not knowing how that will hold

 me up—it'll be the lack of something that I can't build."

     "And that's where you will go back and back and back, as you said about building

 the penstock ?"

     "Back and back is right, if I can find all the necessary raw materials—that's what's

 probably going to put a lot of monkey-wrenches into the machinery." And Stevens went

 to work upon a weapon of offense, fashioning a crude, but powerful bow from a strip of

 spring steel strung with heavy wire.

     "How about arrows ? Shall I go see if I can hit a bird with a rock, for feathers, and

 see if I can find something to make arrows out of?"

     "Not yet—anyway, I'd bet on the birds! I'm going to use pieces of this light brace-

 rod off the accumulator cells for arrows. They won't fly true, of course, but with their

 mass I can give them enough projectile force to kill any small animal they hit, no matter

 how they hit it."

     After many misses, he finally bagged a small animal, something like a rabbit and

 something like a kangaroo, and a couple of round-bodied, plump birds, almost as large

 as domestic hens. These they dressed, with considerable distaste and a noticeable lack

 of skill.

     "We'll get used to it pretty quick, Diana—also more expert," he said when the

 task was done. "We now have raw material for bowstrings and clothes, as well as food."

     "The word 'raw' being heavily accented," Nadia declared, with a grimace. "But

 how do we know that they're good to eat?"

     "We'll have to eat 'em and see," he grinned. "I don't imagine that any flesh is

 really poisonous, and we'll have to arrive at the ones we like best by a process of trial

 and error. Well, here's your job—I'll get busy on mine. Don't go more than a few

 hundred meters away and yell if you get into a jam."

     "There's a couple of questions I want to ask you. What makes it so warm here,

 when the sun's so far away and Jupiter isn't supposed to be radiating any heat ? And

 how about time? It's twelve hours by my watch since sunrise this morning, and it's still

 shining."

     "As for heat, I've been wondering about that. It must 1 be due to internal heat,

 because even though Jupiter may be warm, or even hot, it certainly isn't radiating much,

 since it has a temperature of minus two hundred at the visible surface, which, of course,

 is the top of the atmosphere. Our heat here is probably caused by radioactivity — that's

 the most modern dope, I believe. As for time, it looks as though our days were

 something better than thirty hours long, instead of twenty-four. Of course I'll keep the

 chronometer going on I-P time, since we'll probably need it in working out observations;

 but we might as well let our watches run down and work, eat, and sleep by the sun—not

 much sense in trying to keep Tellurian time here, as I see it. Check?"

     "All x. I'll have supper ready for you at sunset. 'Bye!"

     A few evenings later, when Stevens came in after his long day's work, he was

 surprised to see Nadia dressed in a suit of brown coveralls and high-laced moccasins.

     "How do I look?" she asked, pirouetting gayly.

     "Neat, but not gaudy," he approved. "That's good moleskin—smooth, soft, and

 tough. Where'd you make the raise? I didn't know we had anything like that on board.

 What did you do for thread ? You look like a million dollars —you sure did a good job of

 fitting."

     "I had to have something—what with all the thorns and brush, there was almost

 more of me exposed than covered, and I was getting scratched up something fierce. So

 I ripped up one of the space-suits, and found out that there's enough cloth, fur, and

 leather in one of them to make six ordinary suits, and thread by the kilometer. I was

 awfully glad to see all that thread—I had an idea that I'd have to unravel my stockings or

 something, but I didn't. Your clothes are getting pretty tacky, too, and you're getting all

 burned with those hot coals and things. I'm going to build you a suit of leather for your

 blacksmithing activities."

     "Fine business, ace! Then we can save what's left of our civilized clothes for the

 return trip. What do we eat?"

     "The eternal question of the hungry laboring man! I've got a roasted bongo, a

 fried filamaloo bird, and a boiled warple for the meat dishes. For vegetables, mashed

 hikoderms and pimola greens. Neocorn bread."

     "Translate that, please, into terms of food."

     "Translate it yourself, after you eat it. I changed the system on you today. I've

 named all the things, so it'll be easier to keep track of those we like and the ones we

 don't."

     With appetites sharp-set by long hours -of hard labor they ate heartily; then, in

 the deepening twilight, they sat and talked in comradely fashion while Stevens smoked

 one precious cigarette.

     It was not long until Nadia had her work well in hand. Game was plentiful, and

 the fertile valley and the neighboring upland yielded peculiar, but savory vegetable

 foods in variety and abundance; so that soon she was able to spend some time with

 Stevens, helping him as much as she could. Thus she came to realize the true

 magnitude of the task he faced and the real seriousness of their position.

     As Stevens had admitted before the work was started, he had known that he had

 set himself a gigantic task, but he had not permitted himself to follow, step by step, the

 difficulties that he knew awaited him. Now, as the days stretched into weeks and on into

 months he was forced to take every laborious step, and it was borne in upon him just

 how nearly impossible that Herculean labor was to prove—just how dependent any

 given Earthly activity is upon a vast number of others. Here he was alone—everything

 he needed must be fabricated by his own hands, from its original sources. He had

 known that progress would be slow and he had been prepared for that; but he had not

 pictured, even to himself, half of the maddening setbacks which occurred time after time

 because of the crudity of the tools and equipment he was forced to use. All too often a

 machine or part, the product of many hours of grueling labor, would fail because of the

 lack of some insignificant thing—some item so common as to be taken for granted in all

 Terrestrial shops, but impossible of fabrication with the means at his disposal. At such

 times he would set his grim jaw a trifle harder, go back one step farther toward the

 Stone Age, and begin all over again—to find the necessary raw material or a possible

 substitute, and then to build the apparatus and machinery necessary to produce the part

 he required. Thus the heart-breaking task progressed, and Nadia watched her co-

 laborer become leaner and harder and more desperate day by day, unable in any way

 to lighten his fearful load.

     In the brief period of rest following a noonday meal, Stevens lay flat upon the

 warm, fragrant grass beside the Forlorn Hope; but it was evident to Nadia that he was

 not resting. His burned and blistered hands were locked savagely behind his head, his

 eyes were closed too tightly, and every tense line of his body was eloquent of a strain

 even more mental than physical. She studied him for minutes, her fine eyes clouded,

 then sat down beside him and put her hand upon his shoulder.

     "I want to talk to you a minute, Steve," she said gently.

     "All x, little fellow—but it might be just as well if you didn't touch me. You see, I'm

 getting so that I can't trust myself."

     "That's exactly what I want to talk to you about." A fiery blush burned through her

 deep tan; but her low, clear voice did not falter and her eyes held his unflinchingly. ".I

 know you better than you know yourself, as I've said before. You are killing yourself, but

 it isn't the work, frightfully hard and disheartening as it is, that is doing it—it's your

 anxiety for me and the uncertainty of everything. You haven't been able to rest because

 you have been raging and fuming so at unavoidable conditions—you have been fighting

 facts. And it's all so useless, Steve, between you and me —everything would check out

 on zero if we'd just come out into the open."

     The man's gaunt frame seemed to stiffen even more rigidly.

     "You've said altogether too much or else only half enough, Nadia. You know, of

 course, that I've loved you ever since I got really to know you. You know that I love you

 and you know how I love you—with the real love that a man can feel for only one

 woman and only once in his life; and you know exactly what we're up against. Now that

 does tear it—wide open!" he finished bitterly.

     "No, it doesn't, at all," she replied, steadily. "Of course I know that you love me,

 and I glory in it; and since you don't seem to realize that I love you in exactly the same

 way, I'll tell you so. Love you! Good heavens, Steve, I never dreamed that such a man

 as you are really existed! But you're fighting too many things at once, and they're killing

 you. And they're mostly imaginary, at that. Can't you see that there's no need of

 uncertainty between you and me? That there is no need of you driving yourself to

 desperation on my account? Whatever must be is all x with me, Steve. If you can build

 everything you need, all well and good. We'll be engaged until then, and our love will be

 open and sweet. If worst comes to worst, so that we can neither communicate with

 Brandon and Westfall nor leave here under our own power—even that is nothing to kill

 ourselves about. And yes, I do know exactly what we are facing. I have been prepared

 for it ever since I first saw what a perfectly impossible thing you are attempting. You are

 trying to go from almost the Age of Bronze clear up to year-after-next in a month or two.

 Not one man in a million could have done as much in his lifetime as you have done in

 the last few weeks, and I do not see how even you, with what little you have to work

 with, can possibly build such things as power-plants, transmitters, and ultra-radio

 stations. But what of it ? For the day that it becomes clear that we are to remain here

 indefinitely; that day we will marry each other here, before God. Look around at this

 beautiful country. Could there be a finer world upon which to found a new race? When

 we decided to cut loose from the Arcturus I told you that I was with you all the way, and

 now I'll repeat it, with a lot more meaning. No matter what it's like, Steve, no matter

 where it leads to, I'm with you—to—the—end— of—the—road. Here or upon Earth or

 anywhere in the Universe, Steve, I am yours, just as you are mine—for life and for

 eternity."

     While she was speaking the grim, strained lines upon Stevens' face had

 disappeared, and as she fell silent he straightened up and gently, tenderly, reverently

 he took her lithe body into his arms. Their lips met and held in a long, clinging caress.

     "You're right, sweetheart—everything will check out on zero, to nineteen

 decimals." He was a man transfigured. "I've been fighting windmills and I've been

 scared sick—but how was I to think that a wonder-girl like you could ever love a guy like

 me ? You certainly are the gamest little partner a man ever had. You're the world's

 straightest shooter, ace—you're a square brick if there ever was one. Your sheer nerve

 in being willing to go the whole route makes me love you more than ever, if such a thing

 can be possible, and it certainly puts a new face on the whole cock-eyed Universe for

 me. However, I don't believe it will come to that. After what you've just said, I sure will

 lick that job, regardless of how many different factories it takes to" make one

 armature—I'll show that mess of scrap-iron what kind of trees make shingles!"

     The girl still in his arms, he rose to his feet and released her slowly, reluctantly,

 unwilling ever to let her go. Then he shook himself, as though an overwhelming burden

 had been lifted from his shoulders, and laughed happily.

     "See this cigarette ?" he went on lightly. "The Last of the Mohicans. I'm going to

 smoke it in honor of our engagement." He drew the fragrant smoke deep into his lungs

 and frowned at her in mock seriousness.

     "This would be a nice world to live on, of course, but the jobs here are too darn

 steady. It also seems to be somewhat lacking in modern conveniences, such as steel-

 mills and machine tools. Then, too, it is just a trifle too far from the Royal and Ancient for

 you really to enjoy living here permanently, and besides, I can't get my favorite brand of

 cigarettes around here. Therefore, after due deliberation, I don't believe we'll take the

 place—we'll go back to Tellus. Kiss me just once more, ace, and I'll make that job think

 a cyclone has struck it right on the center of impact. Like Samuel Weller, or whoever it

 was, I'm clear full of Vigor, wim, and witality'!"

     The specified kiss and several others duly delivered he strode blithely away, and

 the little canyon resounded with the blows of his heavy sledge as he attacked with

 renewed spirit the great forging, white-hot from his soak-pit, which was to become the

 shaft of his turbo-alternator. Nadia watched him for a moment, her very heart in her

 eyes, then picked up her spanner and went after more steel, breathing a long and

 tremulous, but supremely happy sigh.
 CHAPTER 4

Ganymedean Life

 Slow, hard, and disheartening as the work had been at first, Stevens had never

 slackened his pace, and after a time, as his facilities increased, the exasperating

 setbacks decreased in number and severity and his progress became faster and faster.

 Large as the Forlorn Hope was, space was soon at a premium, for their peculiarly-

 shaped craft became a veritable factory, housing a variety of machinery and equipment

 unknown in any single Earthly industrial plant. Nothing was ornamental— everything

 was stripped to its barest fundamental necessities—but every working part functioned

 with a smooth precision to delight the senses of any good mechanic.

     In a cavern under the falls was the great turbine, to be full-fed by the crude but

 tight penstock which clung to the wall of the gorge, angling up to the brink of that

 stupendous cataract. Bedded down upon solid rock there was a high-tension alternator

 capable of absorbing the entire output of the mighty turbine. This turbo-alternator was

 connected to a set of converters from which the energy would flow along three great

 copper cables—the receptors of the lifeboats being altogether too small to carry the

 load—to the now completely exhausted accumulators of the Forlorn Hope. All high-

 tension apparatus was shielded and grounded, so that no stray impulses could reveal to

 the possible detectors of the Jovians the presence of this foreign power plant. Housings,

 frames, spiders, every stationary part, were rough, crude, and massive; but bearings,

 shafts, armatures, all moving parts, were of a polished and finished accuracy and

 balance that promised months and years of trouble-free operation. Everything ready for

 the test, Stevens took off his frayed and torn leather coveralls and moccasins—he never

 walked down—and climbed nimbly up the penstock. Opening the head-gate, he poised

 sharply upon its extremity and took off in a perfect swan-dive; floating unconcernedly

 downward toward that boiling maelstrom two hundred feet below. He struck the water

 with a sharp, smooth "slup!" and raced ashore, seizing his suit as he ran toward the

 turbo-alternator. It was running smoothly, and, knowing that everything was tight at the

 receiving end, he lingered about the power plant until he was assured that nothing

 would go wrong and that his home-distilled lubricating oil and grease would keep those

 massive bearings cool.

     Hunger assailed him, and glancing at the sun he noted that it was well past

 dinner-time.

     "Wow!" he exclaimed aloud. "The boss just loves to wait meals—she'll burn me

 up for this!"

     He ran lightly toward "home", eager to tell his sweetheart that the long-awaited

 moment had arrived—that power was now flowing into their accumulators.

     "Hi, Diana of the silver bow!" he called. "How come you no blow the dinner bell?

 Power's on—come give it a look!"

     There was no answer to his hail, and Stevens paused in shocked amazement.

 He knew that never of her own volition would she be out so late—Nadia was gone! A

 rapid tour of inspection quickly confirmed that which he already knew only too well.

 Forgotten was his hunger, forgotten the power plant, forgotten everything except the

 fact that his Nadia, the buoyant spirit in whom centered his Universe, was lost or . . . he

 could not complete the thought, even to himself.

     Swiftly he came to a decision and threw off his suit, revealing the body of a

 Hercules—a body ready for any demand he could put upon it. Always in hard training,

 months of grinding physical labor and of heavy eating had built him up to a point at

 which he would scarcely have recognized himself, could he have glanced into a mirror.

 Mighty but pliable muscles writhed and swelled under his clear skin as he darted here

 and there, selecting equipment for what lay ahead of him. He donned the heavily

 armored space-suit which they had prepared months before, while they were still

 suspicious of possible attack. It was covered with heavy steel at every point, and the

 lenses of the helmet, already of unbreakable glass, had been re-enforced with thick

 steel bars. Tanks and valves supplied air at normal pressure, so that his powerful body

 could function at full efficiency, not handicapped by the lighter atmosphere of

 Ganymede. The sleeves terminated in steel-protected rubber wristlets which left his

 hands free, yet sheltered from attack—wristlets tight enough to maintain the difference

 in pressure, yet not tight enough to cut off the circulation. He took up his mighty war-

 bow and the full quiver of heavy arrows—full-feathered and pointed with savagely

 barbed, tearing heads of forged steel—and slipped into their sheaths the long and

 heavy razor-sharp sword and the double-edged dirk, which, he had made and ground

 long since for he knew not what emergency and whose bell-shaped hilts of steel further

 protected his hands and wrists. Thus equipped, he had approximately his normal

 Earthly weight; a fact which would operate to his advantage, rather than otherwise, in

 case of possible combat. With one last look around the Forlorn Hope, whose every

 fitting shrieked aloud to him of the beloved mistress who was gone, he filled a container

 with water and cooked food and opened the door.

                         * * * * *

 "It won't be long now, now it won't be long," Nadia caroled happily, buckling on her pack

 straps and taking up bow and arrows for her daily hunt. "I never thought that he could

 do it, but what it takes to do things he's got lots of", she continued to improvise the song

 as she left the Hope, with its multitudinous devices whose very variety was a never-

 failing delight to her; showing as it did the sheer ability of the man whose brain and

 hands had almost finished a next-to-impossible task.

     Through the canyon and up a well-worn trail she climbed, and soon came out

 upon the sparsely timbered bench that was her hunting grounds. Upon this day,

 however, she was full of happy anticipation and her mind was everywhere except upon

 her work. She was thinking of Stevens, of their love, of the power which he might turn

 on that very day, and of the possible rescue for which she had hitherto scarcely dared to

 hope. Thus it was that she walked miles beyond her usual limits without having loosed

 an arrow, and she was surprised when she glanced up at the sun to see that half the

 morning was gone and that she was almost to the foothills, beyond which rose a

 towering range of mountains.

     "Snap out of it, girl!" she reprimanded herself. "Go on wool-gathering like this and

 your man'll go hungry— and he'll break you right off at the ankles!" She became again

 the huntress, and soon saw an animal browsing steadily along the base of a hill. It was

 a six-legged, deer-like creature, much larger than anything she had as yet seen. But it

 was meat and her time was short, therefore she crept within range and loosed an arrow

 with the full power of her hunting bow. Unfamiliar as she was with the anatomy of the

 peculiar creature, the arrow did not kill. The "hex-aped", as she instantly named it, sped

 away and she leaped after it. She, like her companion, had developed amazingly in

 musculature, and few indeed were the denizens of Ganymede who could equal her

 speed .upon that small globe, with its feeble gravitational force.

     Up the foothills it darted. Beyond the hills and deep into a valley between two

 towering peaks the chase continued before Nadia's third arrow brought the animal

 down. Bending over the game, she became conscious of a strange but wonderfully

 sweet perfume and glanced up, to see something which she certainly had not noticed

 when the hexaped had fallen. It was an enormous flower, at least a foot in diameter and

 indescribably beautiful in its crimson and golden splendor. Almost level with her head

 the gorgeous blossom waved upon its heavy stem; based by a massive cluster of

 enormous, smooth, dark green leaves. Entranced by this unexpected and marvelous

 floral display, Nadia breathed deeply of the inviting fragrance — and collapsed

 senseless upon the ground. Thereupon the weird plant moved over toward her, and the

 thick leaves began to enfold her knees. This carnivorous thing, however, did not like the

 heavy cloth of her suit and turned to the hexaped. It thrust several of its leaves into the

 wounds upon the carcass and fed, while two other leaves rasped together, sending out

 a piercing call.

     In answer to the sound the underbrush crackled, and through it and upon the

 scene there crashed a vegetable-animal nightmare—the parent of the relatively tiny

 thing whose perfume had disabled the girl.

     Its huge and gorgeous blossom was supported by a long, flexible, writhing stem,

 and its base was composed of many and highly specialized leaves. There were saws

 and spears and mighty, but sinuous tendrils; there were slender shoots which seemed

 to possess some sense of perception; there was the massive tractor base composed of

 extensible leaves which by their contraction and expansion propelled the mass along

 the ground. Parent and child fell upon the hexaped, and soon bones and hair were all

 that remained. The slender shoots then wandered about the unconscious girl in her

 strange covering, and as a couple of powerful tendrils coiled about her and raised her

 into the air over the monstrous base of the thing its rudimentary brain could almost be

 perceived working as it sluggishly realized that, now full fed, it should carry this other

 victim along, to feed its other offspring when they should return to its side.

                         * * * * *

 Barely outside the door of the Forlorn Hope Stevens whirled about with a bitter

 imprecation. He had already lost time needlessly—with a lookout plate he could cover

 more ground in ten minutes than he could cover afoot in a week. He flipped on the

 power and shot the violet beam out over the plateau to the district where he knew Nadia

 was wont to hunt. Not finding her there, he swung the beam in an ever widening circle

 around that district. Finally he saw a few freshly broken twigs, and scanned the scene

 with care. He soon found the trail of fresh blood which marked the path of the flight of

 the hexaped, and with the peculiar maneuverability of the device he was using it was

 not long until he was studying the scene where the encounter had taken place. He

 gasped when he saw the bones and perceived three of Nadia's arrows, but soon saw

 that the skeleton was not human and was reassured. Casting about in every direction,

 he found Nadia's bow, and saw a peculiar, freshly trampled path leading from the kill,

 past the bow, and down the valley. He could not understand the spoor, but it was easily

 followed, and he shot the beam along it at headlong speed until he came up with the

 monstrous creature that was making it—until he saw what burden that organism was

 carrying.

     He leaped to the controls of the lifeboat, then dropped his hand. While the stream

 of power now flowing was ample to operate the lookout plates, yet it would be many

 hours before the accumulator cells would be in condition to drive the craft even that

 short distance.

     "It'll take an hour to get there—here's hoping I can check in on time", he

 muttered, as he took careful note of the location and direction of the creature's trail and

 set off at a fast jog-trot.

     The carnivorous flower's first warning that all was not well was received when

 Stevens' steel-shod feet landed squarely upon its base and one sweeping cut of his

 sword lopped off the malignant blossom and severed the two tendrils that still held the

 unconscious Nadia. With a quick heave of his shoulder he tossed her lightly backward

 into the smooth-beaten track the creature had made and tried to leap away—but the

 instant he had consumed in rescuing the girl had been enough for the thing to seize

 him, and he found himself battling for his very life. No soft-leaved infant this, but a full-

 grown monster, well equipped with mighty weapons of offense and defense. Well it was

 for the struggling man that he was encased in armor steel as those saw-edged, hard-

 spiked leaves drove against him with crushing force; well it was for him that he had his

 own independent air supply, so that that deadly perfume eddied ineffective about his

 helmeted head! Hard and fiercely driven as those terrible thorns were, they could do no

 more than dent his heavy armor. His powerful left arm, driving the double-razor-edged

 dirk in short, resistless arcs, managed to keep the snaky tendrils from coiling about his

 right arm, which was wielding the heavy, trenchant sword. Every time that mighty blade

 descended it cleaved its length through snapping spikes and impotently grinding leaves;

 but more than once a nailing tendril coiled about his neck armor and held his helmet

 immovable as though in a vise, while those frightful, grinding saws sought to rip their

 way through the glass to the living creature inside the peculiar metal housing. Dirk and

 saber and magnificent physique finally triumphed, but it was not until leaf had been

 literally severed from every other leaf that the outlandish organism gave up the ghost.

     Nadia had been tossed out into pure air, beyond the zone of the stupefying

 perfume, and she recovered her senses in time to see the finish of the battle. Stevens,

 assured that his foe was hors de combat, turned toward the spot where he had thrown

 Nadia's body. He saw that she was unharmed, and sprang toward her in relief. He was

 surprised beyond measure, however, to see her run away at a pace he could not hope

 to equal, encumbered as he was; motioning frantically at him the while to keep away

 from her. He stopped, astounded, and started to unscrew his helmet, whereupon she

 dashed back toward him, signaling him emphatically to leave his armor exactly as it

 was. He stood still and stared at her, an exasperated question large upon his face, until

 she made clear to him that he was to follow her at a safe distance, then she set off at a

 rapid walk. She led him back to where the hexaped had fallen, where she retrieved her

 bow and arrows; then, keeping a sharp lookout upon all sides, she went on to a small

 stream of water. She made the dumbfounded man go out into the middle of the creek

 and lie down and roll over in the water, approaching him and sniffing cautiously between

 immersions. She made him continue the bathing until she could detect not even the

 slightest trace of the sweet, but noxious fragrance of that peculiarly terrible form of

 Ganymedean life. Only then did she allow him to remove his helmet, so that she could

 give him the greeting for which they both had longed, and tell him what it was all about.

     "So that's it!" he exclaimed, still holding her tightly in his iron embrace. "Great

 balls of fire! I thought maybe you were still a little cuckoo. Anaesthetic perfume, huh?

 Hot stuff, I'd say—no wonder you bit—I would, too. It's lucky for us I was air-tight—we'd

 both be fee . . . "

     "Clam it!" she interrupted him sharply. "Forget it— don't ever even think of it!"

     "All x, ace. It's out like the well-known light. What to do? It's getting darker than a

 hat, and we're a long ways from home. Don't know whether I could find my way back in

 the dark or not; and just between you and me, I'm not particularly keen on night travel in

 these parts after what's just happened. Are you?"

     "Anything else but," she assured him, fervently. I'd lots rather stay hungry until

 tomorrow."

     "No need of that—I've brought along enough supper for both of us. I'm hungry as

 a wolf, too, now that I have time to think of it. We'll eat and den up somewhere—or

 climb a tree. Those wampuses probably can't climb trees!"

     "There's a nice little cave back there about a hundred meters. We'll pretend it's

 the Ritz," and they soon had a merry fire blazing in front of the retreat. There they ate of

 the provisions Stevens had brought. Then, while the man rolled up boulders before the

 narrow entrance of the cave, Nadia gathered leaves and made a soft bed upon its

 warm, dry floor.

     "Good night, lover," and the girl, untroubled and secure now that Stevens was at

 her side, was almost instantly asleep; but the man was not sleepy. He thought of the

 power plant, even now sending its terrific stream of energy into his accumulators. He

 thought of the ultra-radio—where could he get all the materials needed? He thought of

 his friends, wondering whether or not they would receive his message. He thought of

 Breckenridge and the other human beings who had been aboard the Arcturus,

 wondering poignantly as to their fate. He thought of Newton and of his own people, who

 had certainly given them up for dead long since.

     But above all he thought of the beautiful, steel-true companion lying there asleep

 at his mailed feet, and he gazed down at her, his heart in his eyes. The firelight shone

 through the chinks Between the boulders, casting a flickering ruddy light throughout the

 little cavern. Nadia lay there, her head pillowed upon one strong, brown little hand. Her

 lips were red and sweetly curved, her cheek was smooth and firm as so much brown

 velvet. She was literally aglow with sheer beauty and with perfect health; and the man

 reflected, as he studied her hungrily, that this wild life certainly had agreed with

 her—she was becoming more surpassingly beautiful with every passing day.

     "You little trump—you wonderful, lovely, square little brick!" he breathed silently,

 and bent over to touch her cheek lightly with his lips. Slight as the caress was, it

 disturbed her, and even in her sleep her subconscious mind sent out an exploring hand,

 to touch her Steve and thus be reassured. He pressed her hand and she settled back

 comfortably, with a long, deep breath; and he stretched his ironclad length beside her

 and closed his eyes, firmly resolved not to waste a minute of this wonderful night in

 sleep.

     When he opened them an instant later it was broad daylight, the boulders had

 been rolled away, the fragrance of roasting meat permeated the atmosphere, and Nadia

 was making a deafening clamor, beating his steel breastplate lustily with the flat of his

 huge saber.

     "Daylight in the swamp, you sleeper!" she exclaimed. "Roll out or roll up! Come

 and get it, before I throw it away!"

     "I must've been kind of tired," he said sheepishly, when he saw that she had shot

 a bird and had cooked breakfast for them both while he had been buried in oblivion.

     "Peculiar, too, isn't it?" Nadia asked, pointedly. "You only did about ten day's

 work yesterday in ten minutes, swinging this frightful snickersnee of yours. Why, you

 played with it ~as though it were a knitting-needle, and when I wanted to wake you up

 with it, I could hardly lift it."

     "Thought you didn't want that subject ever mentioned?" he tried to steer the talk

 away from his prowess with the broad-sword.

     "That was yesterday," airily. "Besides, I don't mind talking about you—it's thinking

 about us being—you know

     —that I can't stand."

     "All x, ace. I get you—right. Let's eat."

     Breakfast over, they started down the valley, Stevens carrying his helmet under

 his arm. Hardly had they started, however, than Nadia's keen eyes saw a movement

 through the trees, and she stopped and pointed. Stevens looked once, then hand in

 hand they dashed back to their cave.

     "We'll pile up some of the boulders and you lie low," he instructed her as he

 screwed on his helmet. She snapped open his face-plate.

     "But what about you ? Aren't you coming in, too ?" she demanded.

     "Can't—they'd surround us and starve us out. I'm safe in this armor—thank

 Heaven we made it as solid as we did —and I'll fight 'em in the open. I'll show 'em what

 the bear did to the buckwheat!"

     "All x, I guess, but I wish I had my armor, too," she mourned as he snapped shut

 his plate and walled her into the cave with the same great rocks he had used the night

 before. Then, Nadia safe from attack, he drew his quiver of war-arrows into position

 over his shoulder, placed one at the ready in his bow, and turned to face the horde of

 things rushing up the valley toward him. Wild animals he had supposed them, but as he

 stood firm and raised his weapon shrill whistles sounded in the throng, and he gasped

 as he realized that those frightful creatures must be intelligent beings, for not only did

 they signal to each other, but he saw that they were armed with bows and arrows,

 spears, and slings!

     Six-limbed creatures they were, of a purplish-red color, with huge, tricornigerous

 heads and with staring, green, phosphorescent eyes. Two of the six limbs were always

 legs, two always arms; the intermediate two, due to a mid-section jointing of the six-foot-

 long, almost cylindrical body, could be used at will as either legs or arms. Now, out of

 range, as they supposed, they halted and gathered about one who was apparently their

 leader; some standing erect and waving four hands while shaking their horns savagely

 in Stevens' direction, others trotting around on four legs, busily gathering stones of

 suitable size for their vicious slings.

     Too far away to use their own weapons and facing only one small four-limbed

 creature, they considered their game already in the bag, but they had no

 comprehension of Earthly muscles, nor any understanding of the power and range of a

 hundred-pound bow driving a steel-headed war arrow. Thus, while they were arguing

 Stevens took the offensive, and a cruelly barbed steel war-head tore completely through

 the body of their leader and mortally wounded the creature next beyond him. Though

 surprised, they were not to be frightened off, but with wild, shrill screams rushed to the

 attack. Stevens had no ammunition to waste, and every, time that mighty bow twanged

 a yard-long arrow transfixed at least one of the red horde—and a body through which

 had torn one of those ghastly, hand-forged arrow-heads was of very little use thereafter.

 Accurately-sped arrows splintered harmlessly against the re-enforced windows of his

 helmet and against the steel guards protecting his hands. He was almost deafened by

 the din as the stone missiles of the slingers rebounded from his reverberating shell of

 steel, but he fired carefully, steadily, and powerfully until his last arrow had been loosed.

 Then, the wicked dirk in his left hand and the long and heavy saber weaving a circular

 path of brilliance in the sun, he stepped forward a couple of paces to meet the

 attackers. For a few moments nothing could stand before that fiercely driven blade —

 severed heads, limbs, and fragments of torsos literally filled the air, but sheer weight of

 numbers bore him down. As he fell he saw the white shaft of one of Nadia's hunting-

 arrows flash past his helmet and bury itself to the nock in the body of one of the horde

 above him. Nadia knew that her arrows could not harm her lover, and through a chink

 between two boulders she was shooting into the thickest of the mob, speeding her light

 arrows with the full power of her bow.

     Though down, the savages soon discovered that Stevens was not out. In such

 close quarters he could not use his sword, but the fourteen-inch blade of the dirk,

 needle-pointed as it was and with two razor-sharp, serrated cutting edges, was itself no

 mean weapon, and time after time he drove it deep, taking life at every thrust. Four

 more red monsters threw themselves upon the prostrate man, but, not sufficiently

 versed in armor to seek out its joints, their fierce short spear-thrusts did no damage.

 Presently four more corpses lay still and Stevens, with his to them incredible Earthly

 strength, was once more upon his feet in spite of their utmost efforts to pinion his mighty

 limbs, and was again swinging his devastating weapon. Half their force lying upon the

 field, wiped out by a small, but invincible and apparently invulnerable being, the

 remainder broke and ran, pursued by Stevens to the point where the red monsters had

 first halted. He recovered his arrows and returned to the cave, opening his face-plate as

 he came.

     "All x, sweetheart?" he asked, rolling away the boulders. "Didn't get anything

 through to you, did they ?"

     "No, they didn't even realize that I was taking part in the battle, I guess. Did they

 hurt you while they had you down ? I was scared to death for a minute."

     "No, the old armor held. One of them must've gnawed on my ankle some,

 between the greave and the heel-plate, but he couldn't quite get through. 'Sa darn small

 opening there, too—must've bent my foot 'way round to get in at all. Have to tighten that

 joint up a little, I guess. I'll bet I've got a black and blue spot there the size of my hand—

 maybe it's only the size of yours, though."

     "You won't die of that, probably. Heavens, Steve, that cleaver of yours is a

 frightful thing in action! Suppose it's safe for us to go home?"

     "Absolutely—right now's the best chance we'll ever have, and something tells me

 that we'd better make it snappy. They'll be back, and next time they won't be so easy to

 take."

     "All x, then—hold me, Steve, I can't stand the sight of that, let alone wade

 through it. I'm going to faint or something, sure."

     "As you were!" he snapped. "You aren't going to pass out now that it's all over!

 It's a pretty ghastly mess, I know, but shut your eyes and I'll carry you out of sight."

     "Aren't we out of sight of that place yet?" she demanded after a time.

     "Have been for quite a while," he confessed, "but you're sitting pretty, aren't you

 ? And you aren't very heavy —not here on Ganymede, anyway!"

     "Put me down!" she commanded. "After that crack I won't play with you any more

 at all—I'll pick up my marbles and go home!"

     He released her and they hurried back toward their waterfall, keeping wary eyes

 sharp-set for danger in any form, animal or vegetable. On the way back across the

 foothills Stevens shot another hexaped, and upon the plateau above the river Nadia

 bagged several birds and small animals; but it was not until they were actually in their

 own little canyon that their rapid pace slackened and their vigilance relaxed.

     "After this, ace, we hunt together and we go back to wearing armor while we're

 hunting. It scared me out of a year's growth when you checked up missing."

     "We sure do, Steve," she concurred emphatically. "I'm not going to get more than

 a meter away from you from now on. What do you suppose those horrible things are ?"

     "Which?"

     "Both."

     "Those flowers aren't like anything Tellus ever saw, so we have no basis of

 comparison. They may be a development of a kind of flycatcher, or they may be a link

 between the animal and the vegetable kingdom. However, we don't intend to study 'em,

 so let's forget 'em. Those animals were undoubtedly intelligent beings; they probably are

 a race of savages of this satellite."

     "Then the really civilized races are probably . . ."

     "Not necessarily — there may well be different types, each struggling toward

 civilization. There certainly are on Venus, and there once were on Mars."

     "Why haven't we seen anything like that before, in all these months ? Things

 have been so calm and peaceful that we thought we had the whole world to ourselves,

 as far as danger or men were concerned."

     "We never saw them before because we never went where they lived—you were

 a long ways from your usual stamping-grounds, you know. That animal-vegetable flower

 is probably a high-altitude organism, living in the mountains and never coming as low as

 we are down here. As for the savages—whatever they are—they probably never come

 within five kilometers of the falls. Many primitive peoples think that waterfalls are

 inhabited by demons, and maybe these folks are afflicted the same way."

     "We don't know much about our new world yet, do we?"

     "We sure don't—and I'm not particularly keen on finding out much more about it

 until we get, organized for trouble, either. Well, here we are—just like getting back home

 to see the Hope, isn't it?"

     "It if home, and will be until we get one of our own on Earth," and after Stevens

 had read his meters, learning with satisfaction that the full current was still flowing into

 the accumulators, he began to cut up the meat.

     "Now that you've got the power-plant running at last, what next?" asked Nadia,

 piling the cuts in the freezer.

     "Brandon's ultra-radio comes next, but it's got more angles to it than a cubist's

 picture of a set of prisms; so many that I don't know where to begin. There, that job's

 done— let's sit down and I'll talk at you a while. Maybe between us we can figure out

 where to start. I've got everything to build it lined up except for the tube, but that's got

 me stopped cold. You see, fields of force are all right in most places, but I've got to have

 one tube, and it's got to have the hardest possible vacuum. That means a mercury-

 vapor super-pump. Mercury is absolutely the only thing that will do the trick and mercury

 is one thing that is conspicuous by its absence in these parts. So are tungsten for

 filaments, tantalum for plates, and platinum for leads; and I haven't found anything that I

 can use as a getter, either — a metal, you know, to flash inside the tube to clean up the

 last traces of atmosphere in it."

     "I didn't suppose that such a simple thing as a radio tube could hold you up, after

 the perfectly unbelievable things that you have done already—but I see now how it

 could. Of course the tubes in our receiver over there are too small ?"

     "Yes, they are only receiver and communicator tubes, and I need a high-power

 transmitting tube—a fifty-kilowatter, at least. I'd give my left leg to the knee joint for one

 of those big water-cooled, sixty-kilowatt ten-nineteens right now—it'd save us a lot of

 grief."

     "Maybe you could break up those tubes and use the plates and so on?"

     "I thought of that, but it won't work—there isn't half enough metal in the lot, and

 the filaments in particular are so tiny that I couldn't possibly work them over into a big

 one. Then, too, we haven't got many spare tubes, and if I smash the ones we're using I

 put our communicators out of business for good, so that we can't yell for help if we have

 to drift home—and I still don't get any mercury."

     "Do you mean to tell me there's no mercury on this whole planet?"

     "Not exactly; but I do mean that I haven't been able to find any, and that it's

 probably darned scarce. And since all the other metals I want worst are also very dense

 and of high atomic weight, they're probably mighty scarce here, too. Why ? Because

 we're on a satellite, and no matter what hypothesis you accept for the origin of satellites,

 you come to the same conclusion—that heavy metals are either absent or most awfully

 scarce and buried deep down toward the center. There are lots of heavy metals in

 Jupiter somewhere, but we probably couldn't find them. Jupiter's atmosphere is one

 mass of fog, and we couldn't see, since we haven't got an infra-red transformer. I could

 build one, in time, but it'd take quite a while—and we couldn't work on Jupiter, anyway,

 because of its gravity and probably because of its atmosphere. And even if we could

 work there, we don't want to spend the rest of our lives prospecting for mercury."

 Stevens fell silent, brow wrinkled in thought.

     "You mean, dear, that we're . . ." Nadia broke off, the sentence unfinished.

     "Gosh, no! There's lots of things not tried yet, and we can always set out to drift

 it. I was thinking only of building the tube. And I'm trying to think . . . say, Nadia, what do

 you know about Cantrell's Comet ?"

     "Not a thing, except that I remember reading in the newspapers that it was

 peculiar for something or other. But what has Cantrell's Comet got to do with the high

 cost of living—or with radio tubes? Have you gone nuts all of a sudden?"

     "You'd be surprised!" Stevens grinned at her puzzled expression. "Cantrell's

 Comet is one of Jupiter's comet family, and is peculiar in being the most massive one

 known to science. It was hardly known until after they built that thousand-foot reflector

 on the Moon, where the seeing is always perfect, but it has been studied a lot since

 then. Its nucleus is small, but extremely heavy—it seems to have an average density of

 somewhere around sixteen. There's platinum and everything else that's heavy there,

 girl. They ought to be there in such quantity that even such a volunteer chemist as I am

 could find them."

     "Heavens, Steve!" A look of alarm flashed over Nadia's face, then disappeared

 as rapidly as it had come into being. "But of course comets aren't really dangerous."

     "Sure not. A comet's tail, which so many people are afraid of as being poison

 gas, is almost a perfect vacuum, even at its thickest, and we'd have to wear space-suits

 anyway. And speaking of vacuum . . . whoopee! We don't need mercury any more than

 a goldfish needs a gas-mask. When we get Mr. Tube done, we'll take him out into

 space, leaving his mouth open, and very shortly he'll be as empty as a bobby-soxer's

 skull. Then we'll seal him up, flash him out, come back here, and start spilling our

 troubles into Brandon's shell-like ear!"

     "Wonderful! You do get an idea occasionally, don't you? But how do we get out

 there? Where is this Can-Cell's Comet?"

     ''I don't know, exactly—there's one rub. Another is that I haven't even started the

 transmitter and receptor units. But we've got some field-generators here On board that I

 can use, so it won't be so bad. And our comet is in this part of the Solar System

 somewhere fairly close. Wish we had an Ephemeris, a couple of I-P solar charts, and a

 real telescope."

     "You can't do much without an Ephemeris, I shouldn't think. It's a good thing you

 kept the chronometers going. You know the I-P time, day, and dates, anyway."

     "I'll have to do without some things, that's all," and the man stared absently at the

 steel wall. "I remember something about its orbit, since it is one thing that all I-P vessels

 have to steer clear of. Think I can figure it close enough so that we'll be able to find it in

 our little telescope, or even on our plate, since we'll be out of atmosphere. And it might

 not be a bad idea for us to get away, anyway. I'm afraid of those folks on that space-

 ship, whoever they were, and they must live around here somewhere. Cantrell's Comet

 swings about fifty million kilometers outside Jupiter's orbit at aphelion—close enough for

 us to reach, and yet probably too far for them to find us easily. By the time we get back

 here, they probably will have quit looking for us, if they look at all. Then too, I expect

 these savages to follow us up. What say, little ace—do we try it or do we stay here ?"

     "You know best, Steve. As I said before, I'm with you from now on, in whatever

 you think best to do. I know that you think it best to go out there. Therefore, so do I."

     "Well," he said, finally, "I'd better get busy, then— there's a lot to do before we

 can start. The radio doesn't come next, after all — the transmitter and receptor units

 come ahead of it. They won't mean wasted labor, in any event, since we'll have to have

 them in case the radio fails. You'd better lay in a lot of supplies while I'm working on that

 stuff, but don't go out of sight, and yell like fury if you see anything. We'd both better

 wear full armor every time we go out-of-doors—unless I'm all out of control we aren't

 done with those savages yet. Even though they may be afraid of the demons of the

 falls, I think they'll have at least one more try at us."

     While Nadia brought in meat and vegetables and stored them away, Stevens

 attacked the problem of constructing the pair of tight-beam, auto-dirigible transmitter

 and receptor units which would connect his great turbo-alternator to the accumulators of

 their craft, wherever it might be in space. From the force-field generators of the Forlorn

 Hope he selected the two most suitable for his purpose, tuned them to the exact

 frequency he required, and around them built a complex system of condensers and

 coils.

     Day after day passed. Their larder was full, the receptor was finished, and the

 beam transmitter was almost ready to attach to the turbo-alternator before the calm was

 broken.

     "Steve!" Nadia shrieked. Glancing idly into the communicator plate, she had been

 perfunctorily surveying the surrounding territory. "They're coming! Thousands of them!

 They're all over the bench up there, and just simply pouring down the hills and up the

 valley!"

     "Wish they'd waited a few hours longer—we'd've been gone. However, we're just

 about ready for them," he commented grimly, as he stared over her shoulder into the

 communicator plate. "We'll make a lot of those Indians wish that they had stayed at

 home with their papooses."

     "Have you got all those rays and things fixed up ?"

     "Not as many as I'd like to have. You see, I don't know the composition of the I-P

 ray, since it is outlawed to everybody except the police. Of course I could have found

 out from Brandon, but never paid any attention to it. I've got some nice ultra-violet,

 though, and a short-wave oscillatory that'll cook an elephant to a cinder in about eight

 seconds. We'll keep 'em amused, no fooling! Glad we had time to cover our open sides,

 and it looks as though that meteorite armor we put over the projectors may be mighty

 useful, too."

     On and on the savages came, massed in formations showing some signs of rude

 discipline. This time there was neither shrieking nor yelling; the weird creatures

 advanced silently and methodically. Here and there were massed groups of hundreds,

 dragging behind them engines which Stevens studied with interest.

     "Hm . . . m . . . m. Catapults," he mused. "You were right, girl of my dreams —

 armor and bows and arrows wouldn't help us much right now. They're going to throw

 rocks at us that'll have both mass and momentum. With those things they can cave in

 our side-armor, and might even dent our roof. When one of those projectiles hits, we

 want to be where it ain't, that's all."

     Stevens cast off the heavily-insulated plug connecting the power plant leads to

 his now almost fully charged accumulators, strapped himself and Nadia into place at the

 controls, and waited, staring into the plate. Catapult after catapult was dragged to the lip

 of the little canyon, until six of them bore upon the target. The huge stranded springs of

 hair, fibre, and sinew were wound up to the limit, and enormous masses of rock were

 toilsomely rolled upon the platforms. Each "gunner" seized his trip, and as the leader

 shrieked his signal the six ponderous masses of metalliferous rock heaved into the air

 as one. But they did not strike their objective, for as the signal was given, 'Stevens shot

 power into his projectors. The Forlorn Hope leaped out of the canyon and high into the

 air over the open meadow, just as the six great projectiles crashed into the ground upon

 the spot which, an instant before, she had occupied.

     Rudimentary discipline forgotten, the horde rushed down into the canyon and the

 valley, in full clamor of their barbaric urges. Horns and arms tossed fiercely, savage

 noises rent the air, and arrows splintered harmlessly upon steel plate as the mystified

 and maddened warriors upon the plain below gave vent to their outraged feelings.

     "Look, Nadia! A whole gang of them are smelling around that power plug. Pretty

 soon somebody's going to touch a hot spot, and when he does we'll cut loose on the

 rest of them."

     The huge insulating plug, housing the ends of the three great cables leading to

 the converters of the turbo-alternator, lay innocently upon the ground, its three yawning

 holes invitingly open to savage arms. The chief, who had been inspecting the power-

 plant, walked along the triplex lead and joined his followers at its terminus. Pointing with

 his horns he jabbered orders, and three red monsters, one at each cable, bent to lift the

 plug, while the leader himself thrust an arm into each of the three contact holes. There

 was a flash of searing flame and the reeking smoke of burning flesh—those three arms

 had taken the terrific no-load voltage of the three-phase converter system, and the full

 power of the alternator had been shorted directly to ground through the comparatively

 small resistance of his body.

     Stevens had poised the Forlorn Hope edgewise in mid-air, so that the gleaming,

 heavily armored parabolic reflectors of his projectors, mounted upon the leading edge of

 the fortress, covered the scene below. As the charred corpse of the savage chieftain

 dropped to the ground, it seemed to the six-limbed creatures that the demons of the

 falls had indeed been annoyed beyond endurance by their intrusion; for, as if in

 response to the flash of fire from the power plug, that structure so peculiarly and so

 stolidly hanging in the air came plunging down toward them. From it there reached

 down twin fans of death and destruction: one flaming an almost invisibly incandescent

 violet which tore at the eyes and excruciatingly disintegrated brain and nervous tissues;

 the other dully glowing an equally invisible red, at the touch of which body temperature

 soared to lethal heights and foliage burst cracklingly into spontaneous flame.

     In their massed hundreds the savages dropped where they stood, life rived away

 by the torturing ultra-violet, burned away by the blast of pure heat, or consumed by the

 conflagrations that raged instantly wherever that wide-sweeping fan encountered

 combustible material. In the face of power supernatural they lost all thought of attack or

 of conquest, and sought only and madly to escape. Weapons were thrown away, the

 catapults were abandoned, and, every man for himself, the mob fled in wildest disorder,

 each striving to put as much distance as possible between himself and that place of

 dread mystery, the waterfall.

     "Well, I guess that'll hold 'em for a while," Stevens dropped their craft back into

 its original quarters in the canyon. "Whether they ever believed before that this falls was

 inhabited by devils or not, they think so now. I'll bet that it'll be six hundred Jovian years

 before any of them ever come within a hundred kilometers of it again. I'm glad of it, too,

 because they'll let our power plant alone now. Well, let's get going—we've got to make

 things hum for a while!"

     "Why all the rush ? You just said that we have scared them away for good."

     "The savages, yes, but not those others. We've just turned loose enough

 radiation to affect detectors all over the system, and it's up to us to get this beam

 projector set up, get away from here, and get our power shut off before they can trace

 us. Snap it up, ace!"

     The transmitter unit was installed at the converters, the cable was torn out; and

 having broken the last material link between it and Ganymede, Stevens hurled the

 Forlorn Hope out into space, using the highest acceleration Nadia could endure. Hour

 after hour the massive wedge of steel bored outward, away from Jupiter; hour after hour

 Stevens' anxious eyes scanned his instruments; hour after hour hope mounted and

 relief took the place of anxiety as the screens remained blank throughout every inquiring

 thrust into the empty ether.
 CHAPTER 5

Cantrell's Comet

 Far out in space, Jupiter a tiny moon and its satellites mere pin-points of light, Stevens

 turned to his companion with a grin.

     "Well, Nadia, my ex-groundgripper, here's where we turn spacehounds again.

 Hope you like it better this time, because I'm afraid that we'll have to stay weightless 'for

 quite a while." He slowly throttled down the mighty flow of power, and watched the

 conflicting emotions play over Nadia's face in her purely personal battle against the

 sickening sensations caused by the decrease in their acceleration.

     "I'm sorry, sweetheart." His grin disappeared. "Wish I could take it for you, but. .

 ."

     "But there are times when we've got to fight, our own battles and bury our own

 dead," she interrupted, gamely. "Cut off the rest of that power! I'm not going to be sick—

 I won't be a—what do you spacehounds call us poor earth-bound dubs who can't stand

 weightlessness—weight-fiends, isn't it?"

     "Yes; but you aren't . . ."

     "I know I'm not, and I'm not going to be one, either! I'm all x, Steve—it's not so

 bad now, really. I held myself together that time, anyway, and I feel lots better now.

 Have you found Cantrell's Comet yet ? And why so sure all of a sudden that they can't

 find us ? That power beam still connects us to Ganymede, doesn't it ? Maybe they can

 trace it."

     "At-a-girl, ace!" he cheered. "I'll tell the world you're no weight-fiend—you're a

 spacehound right. Most first-trippers, at this stage of the game, wouldn't be caring a

 whoop whether school kept or not, and here you're taking an interest in all kinds of

 things already. You'll do, girl of my heart—no fooling!"

     "Maybe,1 and maybe you're trying to kid somebody," she returned, eying him

 intently. "Or maybe you just don't want to answer those questions I asked you a minute

 ago."

     "No, that's straight data, right on zero clear across the panel," he assured her.

 "And as for your questions, they're easy. No, I haven't looked for the comet yet,

 because we'll have to drift for a couple of days before we'll be anywhere near where I

 think it is. No, they can't trace us, because there is now nothing to trace, unless they

 can detect the slight power we are using in our lights and so on—which possibility is

 vanishingly small. Potentially, our beam still exists, but since we are drawing no power,

 it has no actual present existence. See?"

     "Uh-uh," she dissented. "I can't say that I .can quite understand how a beam can

 exist potentially and yet not be there actually enough to trace. Why, a thing has to be

 actual or not exist at all—you can't possibly have something that is nothing. It doesn't

 make sense. But lay off of those integrations of yours, please," as Stevens began to

 draw a diagram. "You know that your brand of math is over my head like a circus tent,

 so we'll let it lay. I'll take your word for it, Steve—if you're satisfied, it's all x with me."

     "I think I can straighten you out a little, by analogy. Here's a rough sketch of a

 cylinder, with its shade and shadow. You've had descriptive geometry, of course, and so

 know that a shadow, being simply a projection of a material object upon a plane, is a

 two-dimensional thing—or rather, a two-dimensional concept. Now take the shade,

 which is, of course, this entire figure here, between the cylinder casting the shadow and

 the plane of projection. You simply imagine that there is a point source of light at your

 point of projection: it isn't really there. The shade, then, of which I am drawing a picture,

 has only a potential existence. You know exactly where it is, you can draw it, you can

 define it, compute it, and work with it — but still it doesn't exist; there is absolutely

 nothing to differentiate it from any other volume of air, and it cannot be detected by any

 physical or mechanical means. If, however, you place a light at the point of projection,

 the shade becomes actual and can be detected optically. By a sufficient stretch of the

 imagination you might compare our beam to that shade. When we turn our power on the

 beam is actual; it is a stream of tangible force, and as such can be detected electrically.

 When our switches here are open, however, it exists only potentially. There is no motion

 in the ether, nothing whatever to indicate that a beam ever had actually existed there.

 With me?"

     "Floundering pretty badly, but I see it after a fashion. You physicists are peculiar

 freaks—where we ordinary mortals see actual, solid, heavy objects, you see only empty

 space with a few electrons and things floating around in it; and yet where we see only

 empty space, you can see things 'potentially' that may never exist at all. You'll be the

 death of me yet, Steve! But I'm wasting a lot of time. What do we do now ?"

     "We get busy on the big tube. You might warm up the annealing oven and melt

 me that pot of glass, while I get busy on the filament supports, plate brackets, and so

 on." Both fell to work with a will, and hours passed rapidly and almost silently, so intent

 was each upon his own tasks.

     "All x, Steve," Nadia broke the long silence. "The pyrometer's on the red, and the

 oven's hot," and the man left his bench. Taking up a long paddle and an even longer

 blow-pipe, he skimmed the melt to a dazzlingly bright surface and deftly formed a

 bubble.

     "I just love to talk at you when you've got your mouth full of a blowpipe." Nadia

 eyed him impishly and tucked her feet beneath her, poised weightless as she was. "I've

 got you foul now—I can say anything I want to, and you can't talk back, because your

 bubble will lose its shape if you do. Oh, isn't that a beauty! I never saw you blow

 anything that big before," and she fell silent, watching intently.

     Slowly there was being drawn from the pot a huge, tapering bulb of hot,

 glistening glass, its cross-section at the molten surface varying as Stevens changed the

 rate of draw or the volume of air blown through the pipe. Soon that section narrowed

 sharply. The glass-blower waved his hand and Nadia severed the form neatly with a

 glowing wire, just above the fluid surface of the glass remaining in the pot. Pendant from

 the blowpipe the bulb was placed over the hot-bench, where Stevens, now begoggled,

 begloved, and armed with a welding torch, proceeded to embellish it with sundry necks,

 side-tubes, supports and other attachments of peculiar pattern. Finally the partially-

 assembled tube was placed in the annealing oven, where it would remain at a high and

 constant temperature until its filaments, grids, and plates had been installed. Eventually,

 in that same oven, it would be allowed to cool slowly and uniformly over a period of

 days.

     Thus were performed many other tasks which are ordinarily done either by

 automatic machinery or by highly-skilled specialists in labor—for these two, thrown upon

 their own resources, had long since learned how much specialization may be

 represented by the most commonplace article. Whenever they needed a thing they did

 not have—which happened every day—they had either to make it or else, failing in that,

 to go back and build something that would enable them to manufacture the required

 item. Such setbacks had become so numerous as to be expected as part of the day's

 work; they no longer caused exasperation or annoyance. For two days the jacks-of-all-

 trades worked at many lines and with many materials before Stevens called a halt.

     "All x, Nadia, it's time for us to lay off of the tinkering and turn into astronomers.

 We've been out for fifty I-P hours, and we'd better begin looking around for our heap of

 scrap metal," and, the girl at the communicator plate and Stevens at their one small

 telescope, they began to search the black, star-jeweled heavens for Cantrell's Comet.

     "According to my figures, it ought to be about four hours right ascension, and

 something like plus twenty degrees declination. My figures aren't accurate, though,

 since I'm working purely from memory, so we'd better cover everything from Aldebaran

 to the Pleides."

     "But the directions will change as we go along, won't they?"

     "Not unless we pass it, because we're heading pretty nearly straight at it, I think."

     "I don't see anything interesting thereabouts except stars. Will it have much tail ?"

     "Very little—it's close to aphelion, you know, and a comet doesn't have much of a

 tail so far away from the sun. Hope it's got some of its tail left, though, or we may miss it

 entirely."

     Hours passed, during which the two observers peered intently into their

 instruments, then Stevens straightened up and stretched.

     "Looks bad, ace—we should have spotted it before this. Time to eat, too. You'd

 better . . ."

     "Oh, look here, quick!" Nadia interrupted. "Here's something! Yes, it is a comet,

 and quite close—it's got a little bit of a dim tail."

     Stevens leaped to the communicator plate and, blonde head pressed close to

 brown, the two wayfarers studied the, faint image of the wanderer of the void.

     "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 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 plus 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, heterogenous 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

 masses 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! 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 into their

 sockets the locking plugs of the drag line.

     "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!

 Valves, 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 foolproof. 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 out there somewhere yet because

 of 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 the asteroids.

 There's only a few cubic kilometers of material 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 had not made 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 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 sail 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 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. 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-eight 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 even looking at her, but

 had turned a surprised face from his own task at the sound of her voice. "Excuse it,

 please, Steve. I don't know what's the matter with me—getting jumpy, I guess."

     "I wish that was it, but I'm guessing it isn't." Face suddenly grim and hard,

 Stevens leaped to the communicator plate and shot the beam out into space.

     "You're a fine-tuned instrument yourself, ace, and I'll bet 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 airbreak 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 can't be blamed for that—you couldn't be

 expected to think of everything at once. I think you did wonderfully well as it was—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? Whether they detected us, or came out to this comet after metal,

 same as we did, and found us accidentally? However, it works out to the same

 endpoint—they're apparently out to get us. I'm afraid this is going to be a whole lot like a

 rabbit righting 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 ultraviolet 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. Oh, sweetheart,

 how I want to live with you! But at least, I'm glad that I can go out with you," and her

 glorious eyes were shining with unshed tears as she pressed as close to his side as the

 cumbersome suits would permit.

     "Don't throw in the towel yet. Perhaps they want to capture us alive, like they did

 before; and if so, we may be able to hide out on them somewhere and pull off another

 escape. Things don't look any too bright, perhaps, but I don't quit until my number is

 actually called."

     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 space. Stevens

 seized a projecting brace and clung there, every nerve taut.

     "Something funny here, Nadia," he said after a minute of strained waiting. "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 effortlessly from fragment to fragment, they made their way toward the

 as yet undamaged section of their cruiser. 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 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 there 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 monstrously scientific minds dwelling 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 torpedoes

 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-wracking

 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 peculiarly, lividly 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 could

 have been.

     "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 dose 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 Hop? 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 sunnily,

 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, so there!"
 CHAPTER 6

A Frigid Civilization

 I, Percival van Schravendyck Stevens!" Nadia strode purposefully 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 work when it's got to be done, instead of just between sleeps. However, I'll

 try to do better. Certainly 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 darn-awfully 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—that 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—Phooie!" and he held his nose in a

 pantomime of disgust. "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. He'd think you

 were something his cat had caught and dragged in by mistake. 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 cuckoo who

 indulges in inter-planetary 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 ?"

     "Maybe 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. Maybe 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, over-powered, 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, which 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 the 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 furore in scientific circles, for you are

 impossibility incarnate—personifications of the preposterous. In you wildest fancy has

 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 said that you don't have atomic

 energy, and it doesn't stand to reason that there could be very much power—atomic or

 otherwise—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 our 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 perceive, 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 fluorin 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 fluorin. 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. As a

 chemist I'm an awfully good actress. 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, space-

 worthy structure. And Nadia, the electrician, followed close behind the welder. Wielding

 torch, pliers, and spanner with practiced 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 gimme 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 the 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 a hundred times the size of Luna. Its visible surface

 was an expanse of what they knew to be billowing cloud, shining brilliantly white in the

 pale sunlight, broken only by a dark equatorial band.

     "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 and see," 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 me 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 shadow 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 realized 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 spaceships ; 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

 head-sets. 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

 was 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

 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 would, 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.

     "So far, so good. We will now go out, check its functions, and ascertain why it

 does not function any more. 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, no fooling."

     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 plant 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

 constitutions, I don't see how they ever got it built at all."

     Before them rose an immense truncated cone of metal, upon the top of which

 was situated the power plant. Twelve massive pillars supported a domed 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 x," Stevens spoke to distant Barkovis. "Sure there's nothing on this

 beam ? If it should be hot and I should bridge it, it'd 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 spare 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 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.

     "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 thermocouple, 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 checker-work 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, dear 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 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 adsorbed 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 crudely 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 something 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 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, please 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 7

The Return to Ganymede

 Must 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 onto 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 mirrored

 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 arid 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—good-by, 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, girl-friend, we're off—on a long trek, too, 's what I mean."

     "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're perched on the

 exact apex of the entire universe!"

     "How long is it going to take ?"

     "Don't know. Haven't figured it yet, but it'll be beau-coup 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 were 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 that 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 further 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 that 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 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 obtuse 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 explosion, 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 airbreaks, 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 vessel.

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

 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. 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 electromagnetics 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'd be better, at that. If I forget it, remind me to blow up those two 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 dive; 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 the falls, our power plant, the catapults, V everything. Now, unless something

 interrupts us again, we'll run up our radio tower and give Brandon the long yell."

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

     "Not an awful lot. Everything's 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,

 and that'd be just too bad for us. 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 or something then ? It looks like there's a lot of things that 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 . . ."

     "Clam 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 got

 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; nobody could help it. 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 a wild, impetuous

 lobster, 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'd 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, anyway."

     They again became silent, watching Jupiter, an enormous crescent moon almost

 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 she had receivers tuned to this exact

 frequency. 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 Fantasia 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 each of these he sent out to the

 Sirius in full, 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

 substitute 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 of my heart, and I

 suggest that we sleep for about a week!"

 CHAPTER 8

 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

 minutely studied 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."

     "Good!" 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 Bzarvk 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 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 radio activity 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 harnesses. 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 our 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 in 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 lo 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 first perfected the

 space-ship; and effected a safe landing, first upon the barren, airless moonlet nearest

 them, and then upon fruitful lo. There they made common cause with the hexans

 against the humans, and in a space of time Ionian humanity ceased to exist. Much

 traffic and interbreeding followed between the hexans of Jupiter and those of lo,

 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 lo 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 sciences. 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 can 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 shall 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 rockets and explosives. 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. Ray screens are effective only against rays, and

 the hexans cannot destroy anything that they cannot see before it strikes them. So it is

 that all the vessels of the hexans 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 comparatively ineffectual

 long-range bombardment, but lo is being attacked constantly and it is probable that in a

 few more years lo also will be an abandoned world. Some of you may have received the

 impression 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 Arc turns, 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 of 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 Europan city of the Callistonians.

     "Attention!" barked Captain King. "The name of this city, as nearly as I can come

 to it in English, is 'WRUSZK'. '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, but 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 electromagnetic 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, window-less 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 power, 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 on into the tunnel, with ever 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

 generators 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 nor 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 atomic energy, as we do not have any elements above bismuth. Nor 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 in that eternal fog vision is

 practically useless. 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 horse-power 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?"

     "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."

     "I thought so. Assume that you traveled in a bath 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 I can stand an acceleration of fifty-four meters for two hours, and

 Breckenridge here tests fifty-two. 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 dreadnaught 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-I2 on area five. Give us all

 the Xio 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 electromagnetic 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 bulk 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 wester-most 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 of 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 super-plane 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 manned and .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

 super-plane 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."

     "Nor 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 electromagnetic

 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 gray 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!"

 CHAPTER 9

 The "Sirius" Takes a Hand

 The inter-planetary vessel Sirius loafed along 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 kilo-franks 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 that distant

 satellite. He then started to call the offices 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 "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 Newton.

     "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 a honey, that kid Perce! When I see him I'm going to kiss him on both

 cheeks. He's got enough dope on 'em to hang 'em higher'n Franklin's kite, and we'll nail

 those jaspers to the cross or I'm a polyp! He's crazier'n 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 've got 'em both. We'll have

 'em in three days, and it ought to be fairly simple to dope out the opposite of a tractor,

 too—a pusher or pressor beam. Say, round up the gang, will you, while I'm licking some

 of this stuff into shape for you to tear apart? Where're 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're 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 Inter-Planetary 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

 deheterodyne 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 coverse 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

 dazzingly gold-plated queen of the fleet, waited unattended and disregarded on plus

 time while the entire force of the Inter-Planetary 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 ain'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 get at

 it. 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—so go

 ahead with your own jobs!"

     "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 their native

 planet, 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 pretty quick, then we'll

 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 prevents 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-freezeable,

 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?" West-fall 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 since."

     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 drumhead, 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 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 folders 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. "Sheet I, the equations and fundamentals of

 our new cosmic-radiation drive, which renders us independent of power plants."

     "Theoretical or actual?" Pyraz Amonar asked. "We have known that you have

 been studying the problem, but have heard nothing of its solution."

     "Actual," Brandon assured him. "We have been using it for a month, and have

 just about all the kinks ironed out. You four are the first, outside our own crew, to hear of

 it."

     "Congratulations!" Dol Kenor and the two Martians exclaimed as one, and Kenor

 went on: "An accomplishment indeed, to have concluded a research which has baffled

 the best minds for so long."

     "'Concluded' is good," Brandon replied. "They all helped—especially you four. But

 to go on, the rest of the sheets contain the material sent in by Stevens, and various

 deductions and other work based upon that material. Particular emphasis has been

 placed upon 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 such 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 force-bands 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 information at hand, Brandon directed a beam upon the distant

 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. 'S too bad—don't look like we're

 going to get any action for our money a-tall. 'Sa damn 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 ultralights 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. 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 that 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 horse-power 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 Inter-Planetary 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've we got coming in?"

     "Output, eighty five thousand kilofranks," replied Mac-Donald, 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 wide open or up to sixty five, whichever

 comes first. Can't seem to crush his screens, so 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 ain't necessary yet. He must have

 an open slit somewhere to work through, same as we've got. I'll feel around for it a

 while."

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

     "Hm . . . m . . . Never thought of that—it'd be nice, too . . . Can do, I think. Watch

 'em, Quince, and yell 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 blank-ness 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 Sinus 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. " 'Sa good gag

 they didn't have time to locate our working slit—if they'd pushed that stuff through our

 open channel we'd've got frizzled a bit. 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 sometime, since he's bound to run out of power before we do. I

 don't believe that 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, it was known long ago that the synthesis of any

 unstable isotope of very high atomic number gives an almost perfect accumulator."

     "Boloney!" Brandon snorted. "And the required shielding weighs so much that the

 full power of the perfect accumulator can't lift it off the ground."

     "We could postulate, I think, a form of intelligent life which would not require as

 much shielding as we do."

     "Yeah?" The big physicist almost sneered. "You can postulate that the second

 satellite of the fourth planet of Aldebaran is made of green cheese, too, but you'd have a

 hell of a time proving it. Moreover, you can't postulate an unshielded radiation from an

 unstable isotope that our gadgets here wouldn't tell us about, nor any kind of a force

 screen that can stop neutrons. Or can you?"

     "Not off-hand. However, you are the very last man to deny the possibility of

 either. But to return to the subject in hand: whatever the power system of the Jovians

 may be, what can we do about it?"

     "Don't know yet." Brandon's passion evaporated in an instant. "I do know,

 though, that we ain'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 ain'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, the way it is, and

 we're too apt to take one on the chin while we're doing it. Ought to make it so it'll shoot a

 jolt into the opening, too, while you're at it."

     "We shall begin at once," and the massive Martian 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. Damnation, I wish we had more stuff!"

     "After all, we have everything whose necessity and practicability could have been

 foreseen in the light of the information we had at hand. We can, of course, now go

 further."

     "You chirped it! But we can't let things go on this way or we'll get our fingers

 burned. About time to try the grand slam, don't you think?"

     "I am afraid so."

     "Put everything on the center of the band?"

     "That would probably be best."

     "He can't control, so we'll push him down close to the ground before we go to

 work on him—so we won't have so far to fall if anything gives way. Here's hoping

 nothing does!"

     The Sirius almost against the flaming screens of the Jovian and both vessels

 very close to the surface of the satellite, Brandon tested the power leads briefly,

 adjusted dials and coils, then touched the button which actuated the relays — relays

 which in turn drove home the gigantic switches that launched a fearsome and as yet

 untried weapon. Instantly released, the full seven hundred thousand kilo-franks of their

 stupendous batteries of accumulators drove into the middle frequency of the attacking

 band, and Brandon's heart was in his mouth as he stared into the plate to see what

 would happen. He saw! Everything in the Sirius held fast. Under the impact of the

 inconceivable plane of force the screens of the enemy vessel flared instantly into an

 even more intense incandescence and in that same fleeting instant went down. All

 defenses vanished as the metal sphere fell apart into two halves as would an apple

 under the full blow of a broad-axe.

     Brandon quickly shut off his power and stared in relief into the central

 compartment of the globular ship of space, now laid open, and saw there figures, one or

 two of which were moving weakly. As he looked, one of these feebly attempted to raise

 a peculiar, tubular something toward a helplessly-fettered body. Even as Brandon

 snatched away the threatening weapon with a beam of force he recognized the captive.

     "Great Cat, there's Breckenridge!" he gasped, and directed a lifting beam upon

 the bound and unconscious prisoner. Rapidly but carefully he was brought through the

 double airlock and into the control room, where his shackles were cut away and where

 he soon revived under vigorous and skillful treatment.

     "Any more of you in there ? Did I hit any of you with that beam ?" demanded

 Brandon, intensely, as soon as Breckenridge showed signs of understanding.

     "King's in there somewhere, and there's a Callistonian human being that you

 musn't kill," the chief pilot replied, weakly and with great effort in every word. "Don't

 believe that you hit anybody direct, but the shock was pretty bad," and, having delivered

 his message, he lay back, exhausted.

     "All x. Crown, gimme a squad . . ."

     "Not on your life!" barked the general. "This is my job and I'll do it myself. Your

 job is fighting the Sirius— stay with it!"

     "Not in seven thousand years—I'm in on this, too," Brandon protested, but was

 decisively overruled by Newton.

     "You belong right here at this board, since no one else can handle it the way you

 can. Stay here!" he commanded.

     "All x," grudgingly assented the physicist, and held the Sirius upright, with her

 needle-sharp stern buried a few feet deep in the ground.

     He watched the wreckage jealously while Crowninshield and forty armored men

 issued from the service door in the lower ultra-light compartment and advanced upon

 the two halves of the enemy vessel. As no hostile demonstrations ensued, scaling

 ladders were quickly placed and with weapons at the alert the police boarded the

 hemisphere. There they manacled the still helpless beings visible, and, after laying

 down a fog of stupefying gas, vanished into compartments beyond the metal partitions.

 After a short time they reappeared and climbed down the scaling ladders, carrying

 several inert forms, and Brandon spoke into his transmitter.

     "King all x, Crowninshield ?"

     "I think so. Not being in the control room he was not as badly shocked by the

 passage of the beam as were Breckenridge and those you saw. The things in the other

 rooms were about ready to fight, so we gave them a little whiff of tritylamin, but Captain

 King will be as good as ever in a few minutes."

     "Fine business!" The police entered the Sirius, the service doors clanged shut,

 and Brandon turned to Westfall.

     "While they're coming up guess I'll pick up Perce and Miss Newton. We'd better

 get 'em aboard and beat it, while we're all in one piece!"

     But even before he could send out the exploring beam of his communicator the

 voice of Stevens came from the receiver.

     "Hi, Brandon and Westfall! We've watched the whole show. Congratulations,

 fellows! Welcome to Ganymede! You are in our valley—we're upstream from you about

 three hundred meters; just below the falls, on the meadow side."

     "All x," Brandon acknowledged. "We saw you. Come on out where we can pick

 you up. We've got to get away from here—fast!"

     "We'll carry off the pieces of that ship, too, Quince— we may be able to get a lot

 of pointers from it," and Brandon swung mighty tractor beams upon the severed halves

 of the Jovian vessel, then extended a couple of smaller rays to meet the two little figures

 racing across the smooth green meadow toward the Sirius.
 CHAPTER 10

Among Friends at Last

 The time for the landing of the Sirius was drawing near, and the castaways upon

 Ganymede had donned their only suits of Earthly clothing, instead of the makeshifts of

 moleskin, canvas, and leather they had been wearing so long. Thorns and underbrush

 had pierced and torn their once natty outing costumes, and sparks and flying drops of

 molten metal from Stevens' first crude forges had burned in them many gaping holes.

     "I did the best I could with them, Steve, but they look pretty crumby," Nadia

 wrinkled her nose as she studied the anything but invisible seams, darns, and staring

 patches everywhere so evident, both in her own apparel of gray silk and in the heavy

 whipcord clothing of her companion.

     "You did a great job, considering what you had to work with," he reassured her.

 "Besides, who cares about a few patches ? I feel a lot more civilized in my own clothes,

 don't you?"

     "Well . . . yes," she admitted. "They're silk, anyway, even if they don't look like

 much, and I'm just reveling in the feel of them next to me after the horrible, rough,

 scratchy things I've been wearing. See anything yet ?"

     "Not yet." Stevens had been scanning the heavens with a pair of binoculars.

 "That doesn't mean much, though, as they'll be just about in the sun and they'll be

 coming like a scared dog. Might as well put away these glasses—we probably won't be

 able to see them until they're right on top of us."

     "What shall we take with us ?"

     "Don't know—nothing, probably, since they must have a campaign already

 mapped out. I'd like to salvage a lot of this junk, but I'm afraid we won't be able to. I'm

 going to take my bow and arrows, though, aren't you?"

     "Absolutely! That's one thing that's better than anything I ever had on Earth. This

 bow of mine is perfect."

     "There they are! Three rousing cheers! Say, but that old hulk looks good to me!"

     "Doesn't she, though!" cried Nadia, vibrant with excitement. "You know, Steve,

 I've hardly dared really to believe it until this very minute. Oh look! What's that?"

     The Sirius had stopped in midair and they could see, far in the distance, the tiny

 sphere of the Jovians, rushing to the attack.

     "Oh, how horrible!" cried the girl, her voice breaking. "I'm afraid, Steve . . ."

     "You needn't be, ace. I've told you they won't go off half-cocked as long as

 Westfall is on the job. They're ready for anything, or they wouldn't be here—but I wish

 that they had that Titanian mirror and a couple of those bombs, just the same!"

     In a moment more the Jovian plane of force was launched, the powerful ray-

 screens flared into white-hot, sparkling defense, and the battle was on. Held spellbound

 as the castaways were by that spectacular duel, yet Stevens' trained mind warned him

 of the perils of their position.

     "Grab your bow and we'll beat it!" and he rapidly led her away from the steel

 structures to an open hillside, well away from any projection, tree, or sharp point of rock.

 "If that keeps up very long we're going to see some real fireworks, and the chances are

 that our plant here will be a total loss. Everything is grounded, of course, but ordinary

 grounds won't amount to much in what's coming."

     "What are you talking about?" demanded Nadia.

     "Look!" he replied, pointing, and as he spoke a terrific bolt of lightning launched

 itself from the incandescent screen of the Jovian vessel upon their slender ultra-radio

 tower, which subsided instantly into a confused mass of molten and twisted metal.

     As the power of the beams was increased and as the combatants drew nearer

 and nearer the ground the lightning display grew ever more violent. Well below the

 canyon as the warring vessels were, the power-plant and penstock did not suffer and

 only a few discharges struck the Forlorn Hope —discharges which were carried easily

 to ground by the enormous thickness of her armor — but every prominent object for

 hundreds of yards below the Hope was literally blasted out of existence. Radio tower,

 directors, and fittings ; trees, shrubs, sharp points of rock—all were struck again and

 again; fused, destroyed, utterly obliterated by the inconceivable energy being dissipated

 by those impregnable screens of force. Even almost flat upon the ground as the

 spectators were, each individual hair upon their heads strove fiercely to stand erect, so

 heavily charged was the very air. Stevens' arm was blue for days, such was Nadia's grip

 upon it, and she herself could scarcely breathe in that mighty arm's constriction—but

 each was conscious only of that incredibly violent struggle, of that duel to the death

 being waged there before their eyes with those frightful weapons, hitherto unknown to

 man. They saw the Sirius triumphant, and Stevens led the dancing girl back into their

 dwelling of steel.

     "Danger's all over now. Radio's gone, but we should fret about that. It has done

 its stuff—we can use the communicators. And now, sweetheart, I'm going to kiss you—

 for the first time in seven lifetimes." His voice was unsteady as he swept both arms

 around her and pressed her close. "I'm shaking like a leaf. It was the only possible way

 out, of course, but good Lord, how hard it has been not even to touch your hand for the

 last six months!"

     "I know, lover mine." Nadia clung to him and returned his caresses with a fierce

 intensity. "It's been just as hard for me, but we couldn't have stood it at all any other

 way— thank Heaven we won't have to fight ourselves much longer!"

     Locked in each others' arms they watched the scene until Stevens thought it time

 to send his message. Then, running hand in hand toward the huge space-cruiser, they

 were snatched apart and drawn up toward the double airlocks of the main entrance.

 Pressure gradually brought up to normal, they were ushered into the control room,

 where Nadia glanced around quickly and almost took her father off his feet by her

 tempestuous rush into his arms.

     "Oh, Daddy darling—you old dear! I just knew you'd come along! I haven't seen

 you for a million years!" she exclaimed, rapturously. "And Bill, too—wonderful!" as she

 fervently embraced a young man wearing the uniform of a lieutenant of Inter-Planetary

 Police. "Ouch, Bill—you're breaking all my ribs!"

     "Well, you cracked three of mine. Maybe you don't know how husky you are, but

 you've got a squeeze like a boa constrictor!" He held her off at arms' length and studied

 her with admiration. "Gee, it's fine to see you again, sis. You're looking great, too—I

 think I'll bring my girl out here to live. You always were a knockout, but now you're the

 dizziest thing I ever saw!"

     He made his way through the group surrounding Stevens, while Nadia and her

 father talked earnestly.

     "I'm Bill Newton. Thanks," he said, simply, holding out his hand, which was taken

 in a bone-crushing grip.

     "Bring him over here, Bill!" Nadia called before Stevens could find a reply.

     "I don't know how to say anything, Stevens," the officer continued, in

 embarrassment, as the two men turned to obey the summons. "She's a good kid, and

 we think a lot of her. We'd about given her up. We . . . She . . . Oh, hell, what's the use?

 You know what I mean. You're there, Stevens, like a . . ."

     "Clam it, ace!" Stevens interrupted. "I get you to nineteen decimals. And you

 don't half know just what a good kid she really is. She's the reason we're here—we were

 down pretty close to bed-rock for a while, and she stood up when I wilted. She's got

 everything. She . . ."

     "Clam it yourself, Steve! Don't believe a word of it, Dad and Bill. Wilt!" Nadia's

 voice dripped scorn. "Why, he di . . ."

     "Please!" Newton's voice was somewhat husky as he silenced the clamor of the

 three young people, all talking at once. "I will not embarrass you further by trying to say

 something that no words can express. You told me that you would take care of her, and

 I learn that you have done so."

     "I did what I could, but most of the credit belongs to her, no matter what she

 says," Stevens insisted. "Anyway, sir, here she is; alive, well, and . . . unharmed," and

 his eyes bore unflinchingly the piercing gaze of the older man, who was reassured and

 pleased by what he read therein. "One thing I want to say right now, though, that may

 make you feel like canceling the welcome. I loved Nadia even before the Arcturus was

 attacked, and since then, coming to know her as I have, the feeling hasn't lessened

 any."

     "Nadia has already told me all about you two, and the welcome stands. If you

 could take care of her as well as you have done since you left the Arcturus, I have no

 doubt of your ability to take care of her for life. We have been examining the work you

 have done here, son, and the more I saw of it the more amazed I became that you

 could have succeeded as you did. We are deeply indebted . . . Just a minute! There's

 my call—I'm wanted in Fifteen. I'll see you again directly."

     "Hi, Norm!" Stevens further relieved the surcharged atmosphere. "As soon as

 you and Quince can leave those controls come over and see us, will you?"

     "All x—coming up!" sounded Brandon's deep and pleasant bass, and the two

 rescuers, who had tactfully avoided the family reunion, came over and greeted the third

 of their triumvirate.

     "Ho, Perce—you look fit." Brandon ran an expert hand over Stevens' arm and

 shoulder. "Looks like he might last a round or two, don't he, Quince ?"

     "You are looking fine, Steve. Neither of you appear any the worse for your

 experiences. So this is Nadia ? We have heard of you, Miss Stevens."

     "I believe that, knowing Dad. Thanks, both of you, for digging us out. I've heard

 about you two, too, and I'm going to kiss you, whether you like it or not," and she did so,

 fervently.

     Westfall, the silent and reserved, was taken aback, but Brandon met her more

 than half-way.

     "All x, Nadia—payment in full received and hereby acknowledged," he laughed,

 as he allowed her feet to return to the floor. "Even if it was some stout lads from Mars

 and Venus that did all the work we'll take the reward— especially since Alcantro and

 Fedanzo couldn't feel even such a high-voltage salute as that one was, and I can't

 picture you kissing a Venerian even if you could get to him. Whenever you get lost

 again be sure to let us know, now that you've got our address. If I know Perce at all,

 you've heard of us 'til you're sick of it and us—'sa weakness of his, talking too much."

     "Why, it's no such th . . ." began Nadia, but broke off as an aide came up and

 saluted smartly.

     "Pardon me, but General Crowninshield requests that Doctor Brandon, Doctor

 Westfall, and Doctor Stevens join the council in Lounge Fifteen as soon as is

 convenient." He saluted again and turned away.

     "Yeah, 'sright, folks—we've got to take a lot of steps, fast—see you later," and

 Brandon, taking each of the other two by an arm, marched them away toward the

 designated assembly room.

     There, already seated at a long table, were Czuv, King, and Breckenridge> all

 fully recovered, engaged in earnest conversation with Newton and Crowninshield.

 Alcantro and Fedanzo, the Martian scientists, were listening intently, as were the two

 Venerians, Dol Kenor and Pyraz Amonar. The eyes of the three newcomers, however,

 did not linger upon the group at the table, but were irresistibly drawn to one corner of

 the room, where six creatures lay in the heaviest manacles afforded by the stores of the

 Inter-Planetary Police. Not only were they manacled, but each was facing a ray-

 projector, held by a soldier whose expression showed plainly that he would rather press

 the lethal contact than not.

     "Oh!—those the things we're fighting ?" Brandon stopped at the threshold and

 stared intently at the captive hexans. Goggling green eyes glaring venemously, they

 were lying quiet, but tense; mighty muscles ready to burst into berserk activity should

 the attention of a guard waver for a single instant.

     But little more than half as large as the savage creatures with whom Stevens had

 fought in the mountain glade upon Ganymede, the hexans resembled those aborigines

 only as civilized men might resemble gigantic primordial savages of our own Earth.

 Brandon's gaze went from short, powerful legs up a round, red body to the enormous,

 freakish double pair of shoulders, with its peculiar universal jointing. From the double

 shoulders sprang four limbs, the front pair of which were undoubtedly arms, terminating

 in large, but fairly normal, hands. The intermediate limbs were longer than the legs and

 were much more powerful than the arms, and ended in members that were very

 evidently feet and hands combined. What in a human being would be the back of the

 hand was the sole of the foot—when walking upon that foot the long and dexterous

 thumb and fingers were curled up, out of the way and protected from injury, in the palm

 of the hand. From the monstrous shoulders there rose a rather long and very flexible,

 yet massive and columnar neck, supporting a head neither human nor bestial—a head

 utterly unknown to Terrestrial history or experience. The massive cranium bespoke a

 highly-developed and intelligent brain, as did the three large and expressive, peculiarly

 triangular eyes. The three sensitive ears were very long, erect, and sharply pointed.

 Each was set immediately above an eye, one upon each side of the head and one in

 front. Each ear was independently and instantly movable, in any direction, to catch the

 faintest sound. The head, like the body and limbs, was entirely devoid of hair. The

 horns, so prominent in the savages Stevens had seen, were in this highly intelligent

 race but vestigial—three small, sharp, black protuberances only an inch in length, one

 surmounting each ear, outlining the lofty forehead. The nose occupied almost the whole

 middle of the face and was not really a nose—it developed into a small and active

 proboscis. The chin was receding almost to the point of disappearance, so that the

 mouth, with its multiple rows of small, sharp, gleaming-white teeth, was almost hidden

 under the face instead of being a part of it. Such were the hexans, at whom the Big

 Three stared in undisguised amazement.

     "Attention, please!" Newton called the meeting to order. "We have learned that all

 the passengers of the Arcturus, and all the crew save three, are alive and safe for the

 time being. Most of them are upon the satellite Europa. However, I understand that we

 are not yet sufficiently well armed to withstand an attack in force, such as will certainly

 develop when we move to rescue them. This seems to be a war of applied

 physics—Doctor Brandon, as spokesman for the scientific forces of the expedition, what

 are your suggestions?"

     "Anticipating an attack in response to signals probably sent out by the enemy, I

 headed directly south immediately. We are now well south of the ecliptic, and are

 traveling at considerably more than full Martian acceleration. Before making any

 suggestions, I should like to hear from Captain Czuv, who is more familiar than are we

 with the common enemy. Are they apt to follow us, can they detect us if we should drift

 at constant velocity, and can we search the brains of the prisoners with his Callistonian

 thought-exchanger, if he should build one with our help ?"

     "If they are close enough to us to overtake us without too much lost time they will

 certainly attack us," Czuv answered at a nod from Newton. "Ordinarily they would

 pursue us to the limits of the Solar System if necessary, but since they have suffered

 reverses of late and cannot spare any vessels they will probably not pursue us far. Yes,

 they can detect us, even without the driving rays, since this vessel uses much low-

 tension, low-frequency electricity in its automatic machinery, lights and so on. No; our

 thought-transformer cannot take thoughts by force, and the hexans will exchange no

 ideas with us. They are implacable and deadly foes of all humanity, irrespective of

 planet or race. Mercy is to them unknown—they neither give nor take quarter."

     "I can bear him out in that," Crowninshield interposed grimly. "The first one to

 recover snapped our ordinary handcuffs like so much thread and literally tore four men

 to pieces before the rest of us could ray him. Will you need me longer, Director

 Newton?"

     "I think not, General. Captain Czuv, you have made no headway with them?"

     "None whatever, as I foretold. They understand me thoroughly, since two of them

 speak my own tongue, but nothing that they have said can even be repeated here. I

 knew from the first that all such attempts would be fruitless, but I have tried—and failed.

 I suggest what I suggested at first—put them to death, here and now as they lie there,

 for most assuredly they will in some way contrive to take toll of lives of your own

 humanity if you allow them to live."

     "You may be right, but neither the General nor myself can give the order for their

 death, since Inter-Planetary law does not countenance such summary action. However,

 the guards are fully warned of the peril, and will ray every prisoner at the first sign of

 unruliness. General Crowninshield, you may remove the prisoners and deal with them in

 accordance with . . ."

     Pandemonium reigned. At Crowninshield's signal for the guards to leave the

 room with their captives, all six had strained furiously at their bonds and three of them

 had broken free in a flash, throwing themselves upon the guards with unthinkable

 ferocity. Stevens, seeing a ray-projector in a hand of one of the prisoners, hurled his

 heavy chair instantly and with terrific force. The projector flew into the air, shattered and

 useless, while the hexan was knocked into a corner by the momentum of the massive

 projectile and lay there, stunned and broken. Brandon, likewise reacting

 instantaneously, had bent over and seized a leg of the table, bracing his knee against

 the corner. With a mighty lunge of his powerful body he wrenched out the support and

 with a continuation of the same motion he brought the jagged oak head of his terrible

 club down full upon the crown of the second hexan, who had already torn one guard

 apart and was leaping toward Czuv, his hereditary foe. In mid-flight he was dashed to

 the floor, his head a shapeless, pulpy mass, and Brandon, bludgeon again aloft, strode

 deeper into the fray. For a brief moment searing lethal beams probed here and there,

 chains clanked and snapped, once more that ponderous and irresistible oaken mace fell

 like the hammer of Thor, again spattering brains and blood abroad as it descended —

 then again came silence. The six erstwhile prisoners lay dead, but they had taken five of

 the guards with them—literally dismembered, hideously torn limb from limb by the

 superhuman, incredible physical strength and utter ferocity of the hexans.

     By common consent the meeting was adjourned to another room, for the

 business in hand could not be postponed.

     "Captain Czuv was right—we Tellurians could not believe in the existence of

 such a race without the evidence of our own senses," Newton re-opened the meeting.

 "From this time on we take no prisoners. Doctor Brandon, you may resume."

     "The detectors and lookouts will give ample warning of any attack, and Doctor

 Westfall has suggested that we should have all possible facts at hand before we try to

 decide upon a course of action. We should like to hear the full reports of Captain King,

 Captain Czuv, Chief Pilot Breckenridge, and Doctor Stevens."

     The four men told their stories tersely and rapidly, while the others listened in

 deep attention. As the last speaker sat down Newton again turned to Brandon, who

 silently jerked his head at Westfall, knowing his own inadequacy in such a

 situation—realizing that here was needed Westfall!s cold and methodical thinking.

     "Director Newton and gentlemen," Westfall spoke calmly and precisely. "We have

 much to do before we will be able to meet the hexans upon equal terms. We have many

 new fields of force and rays to develop, of whose nature and necessity Doctor Brandon

 is already aware. Then, too, we must recalculate our visirays so that we can operate at

 greater range and efficiency. We must also examine the hexan space-ship which we are

 towing, to do which it will be desirable to drift at constant velocity for a time. In it we may

 find instruments or devices as yet unknown to us. It also occurs to me that since this is

 an Inter-Planetary Police problem of the first magnitude we should at once get in touch

 with Police Headquarters, so that the Peace Fleet can be armed as we ourselves are, or

 shall be, armed; for a large and highly efficient fleet will be necessary to do that which

 must be done. It is, of course, a foregone conclusion that Inter-Planetary humanity .will

 support the humanity of Callisto against the hexans.

     "It is also self-evident that we must stay here and rescue the Tellurians now upon

 Europa and Callisto, but we are not yet in position to decide just how that rescue is to

 be accomplished. Four courses are apparently open to us. First, to attempt it as soon as

 we shall have strengthened our armament as much as is now possible. That would

 invite a massed attack, and in my opinion would be foolish— probably suicidal. Second,

 to stand by at a distance until the rocket-ship is launched, then to escort it back to the

 Earth. Third, to aid the Callistonians as much as possible while awaiting the completion

 of the rocket-vessel. Fourth, and perhaps the most feasible and quickest, it may be

 possible for the Callistonian rocket-ships to bring our fellow-Tellurians, a few at a time,

 to us here out in space, since they are apparently able to come and go at will. However,

 I would recommend that we make no plans for the rescue as yet—there is little use in

 attempting to deal with an ever-changing situation until we are ready to act forthwith. I

 suggest that we strengthen our offensive and defensive armament first, then secure

 information as to the exact status of affairs, both upon Callisto and upon Europa. Then,

 ready to act, we will do at once whatever seems called for by the situation then

 obtaining."

     "The program as outlined seems eminently sensible— are there any comments

 or suggestions ?" None being offered, Director Newton adjourned the meeting and each

 man attacked his particular problem.

     True to Czuv's prediction the hexans did not deem it worth while to pursue the

 Terrestrial vessel, so obviously and so earnestly fleeing from them, and shortly the

 acceleration was cut off, to render possible a thorough study of the two halves of the

 spherical warship of the enemy. Scientists donned space-suits and studied every

 feature of the strange vessel, while mechanics dismantled and transferred to the Sinus

 every device and instrument of interest. One or two novel and useful applications of

 rays and forces were found, their visirays and communicators in particular being of a

 high degree of efficiency; but upon the whole the science of the hexans was found to be

 inferior to that now known to the scientists of Inter-Planetary's flying laboratory. Brandon

 studied the hexan power-system most carefully, and, everything in readiness and after a

 long talk with Westfall, he called a general conference in the control-room.

     "Gentlemen, we have done about everything we can do for the time being. By

 combining the best features of the visirays and communicators of the hexans with our

 own newly-perfected devices we now have a really excellent system of communication.

 Our friends from Mars and Venus have so altered and enlarged our force-controls that

 our offensive and defensive fields, rays, and screens leave little to be desired. In power

 we are far ahead of the enemy. They apparently know nothing of the possibilities of

 cosmic radiation, but depend upon tight-beam transmission from their own power-

 plants—which transmission they have perfected to a point far beyond anything reached

 by us of the three planets. They do not use accumulators, and therefore their dissipation

 is limited to their maximum reception, which is about seventy thousand kilofranks. Since

 we can dissipate ten times that amount of energy we could withstand for a short time

 the simultaneous attacks of ten of their vessels. Eleven or more of them, however,

 would be able to crush our defensive screens—and Captain Czuv has seen as many as

 a hundred of their space-ships in one formation. Furthermore, since they have several

 times our maximum acceleration they could concentrate quickly upon any desired point.

 We could not escape them by flight if they really set out to overtake us, which they

 certainly will do if we again venture into their territory. Therefore it is clear that we

 cannot subject ourselves to any attack in force and it follows that we cannot do much of

 anything until the police fleet of some five hundred vessels can be re-armed and can

 join us near Callisto. This will require several months at best. As you already know, it

 has been decided that we should not return to any of the minor planets, as to do so

 might invite a hexan attack upon our as yet unprepared police fleet. We are now

 heading for Uranus, in the hope that such a course will distract the attention of the

 hexans from Tellus, even though they probably already know that we are Tellurians.

 Our new communicator will reach any member of the Jovian system from this point. It

 has been decided that it is safe to use it, since it employs an almost absolutely tight

 beam of very small diameter, and since we know that that one hexan vessel, at least,

 had no apparatus sufficiently sensitive to detect a beam of that nature. We will therefore

 now get in touch with the Callistonians and with our own people."

     Brandon seated himself before the communicator screen, and while the others

 packed themselves closely around his stool he snapped on the visiray and turned the

 dials which directed that invisible, immensely complex beam through space. The screen

 was apparently in itself a coign of vantage, flying through space with the velocity of light,

 and the watchers gasped involuntarily and drew themselves together as with that

 unthinkable speed they flashed down toward the surface of Callisto. So realistic was the

 impression that they themselves were hurtling through the void that they could scarcely

 reason themselves into believing their positive knowledge that the impending collision

 was not an actual happening! Reducing the velocity of the projection abruptly as it

 approached the satellite, Brandon flashed it down into a crater indicated by Czuv, and

 along a tunnel to the city of Zbardk, where the Callistonian captain held a long

 conversation with the Council of the nation. Frowning in thought, he turned to Newton

 and spoke seriously and slowly.

     "Immediately after the loss of our super-plane, with the supposed death of King,

 Breckenridge, and myself, the other Tellurian officers were returned to Europa> since

 even they could be of no assistance to us Callistonians in our struggle against the new,

 high-acceleration vessels of the hexans. The present situation is much more serious

 than I would have believed possible. The last vessel going to visit Wruszk, our city upon

 Europa, was caught and destroyed by the hexans, and for many weeks no ship nor

 message has come from there to Callisto. In spite of the fact that the hexan fleet is

 smaller than ever before they are guarding Europa very closely. It is feared that they

 may have found and destroyed our city there — an expedition is even now about to set

 out in a desperate attempt to learn the fate of our fellows."

     "Suppose the rays of the lifeboats were detected in landing?" asked Brandon.

 "That might have given them a clue."

     "Possibly; but it is equally possible that our own men became careless in the

 operation of one of our own vessels. Having been unmolested so long, they might have

 relaxed their vigilance. We may never know."

     "Tell 'em to cancel the expedition—we'll shoot the visiray over there right now

 and find out all about it. We'll let 'em know pretty quick. Also you might tell 'em that

 you've got complete plans and specifications for all the weapons that the hexans have,

 and a couple besides, and that the quicker they shoot a ship out here after you the

 sooner they can get to building some stuff to blow those hexans clear out of space!"

     It was the work of only a few moments to drive the visiray projection to Europa,

 where Czuv, to the great relief of all, found that the hexans had not yet discovered

 either Wruszk or the Terrestrial workings. All Europan humanity, fully aware of the

 hexan investment, was exerting every possible precaution against discovery by the

 enemy. This information was duly flashed to the Council of Callisto, and the projection

 was then hurled across the intervening reaches of space and into the cavern in which

 was being built the enormous rocket-ship in which the Terrestrial refugees were to

 attempt the long voyage back to their own distant planet.

     It took some little time to convince Doctor Penfield that there had been projected

 into the empty air of his little sanctum an absolutely invisible and impalpable structure of

 pure force capable of receiving and transmitting voice and vision. Once convinced of the

 reality of the phenomenon, however, the speaker beside Brandon's communicator

 screen fairly rattled under the fervor of his greeting, so great was his pleasure at the

 arrival of the expedition of relief and in knowing that King and Breckenridge, whom they

 had of course given up for dead, were aboard the Inter-Planetary vessel.

     Penfield reported that the work upon the great rocket-ship was progressing

 satisfactorily, although of course slowly, since it was so much larger than any vessel

 there-to-fore constructed by the Callistonians. Newton in turn informed the autocrat of

 the stranded Terrestrials as to the status quo of the rescuing party.

     "Of course, because of the hexan blockade, you cannot take us off until they

 have been wiped out, which will be several months at best." The surgeon said, slowly,

 and a shadow came over his face as he spoke. "Well, what can't be cured . . ."

     "Trouble with the personnel?" King broke in sharply.

     "Personnel, yes; but not trouble in the sense you mean —we have had none of

 that. It is only that there are four more of us now than there were . . ."

     "Huh? How come?" demanded Brandon, in astonishment.

     "Four babies have been born to us here so far, and several more are coming.

 They are the ones I'm worried about. Most normal adults can stand it here without any

 serious effects, but this thin atmosphere and weak gravity are certain to result in

 abnormal development of children. However, there may be another way out of it. Are

 you using normal acceleration, or have you Martians aboard?"

     "Both," replied Brandon. "We are carrying two inhabitants of Mars, but Alcantro

 and Fedanzo are not ordinary Martians. They have been in constant training ever since

 we left Tellus, and now they can stand as high an acceleration as a weak Tellurian.

 We're riding at normal."

     "Good! As you already know, there has been no communication of late between

 here and Callisto. It had already been decided, however, that one more voyage must be

 risked, in order to bring back material which is most urgently needed. Since the vessel

 will leave here light and is large enough to carry about thirty passengers on a short trip

 with some crowding, the Council will probably approve of having it carry some of our

 passengers out to the Sirius—especially now, since a vessel must visit you anyway, to

 get Captain Czuv and the specifications of the new armament. All these things can be

 done with one vessel in one trip."

     "That sounds fine!" boomed King. "It will give me a chance to get back there

 where I belong, too. Who-all are you sending out ?"

     "The seven couples who either have babies already or who will have them in the

 next few months; and our unattached women, a few of whom aren't standing the gaff

 any too well. You won't be in the red very deeply on the deal, either—while two or three

 of the passengers I am sending you will certainly be unwelcome, anybody could use,

 anywhere, such men as Commander Sanderson and Lieut. . . ."

     "Sanderson!" interrupted King. "Why, he wasn't— when did he get married?"

     "The day after we arrived here," replied the surgeon. "His fiancee was aboard the

 Arcturus, and when they found out how long we would have to be here, they very

 sensibly decided not to wait."

     "Were there any others got married there ?" demanded Nadia, who, standing

 between Stevens and her father, had been an interested listener.

     "Plenty of them! Fourteen of our young women passengers have married here

 upon Europa. A few married fellow-passengers, but most of them picked out officers of

 the Arcturus. You'll find your staff made up pretty largely of Benedicts now, King! We've

 been here a year, you know, and time will tell! Young Commander Sanderson's a fine

 baby—he'll be a credit to the IPC some day, if we can get him aboard the Sirius, where

 he can get a good start. We could give our babies normal air pressure here by building

 special rooms, but we cannot give them the normal acceleration necessary to develop

 their muscles properly."

     "Well, we'd better snap over to Callisto and take this up with the Council,"

 Brandon put in. "I don't imagine that there will be any objections, so you might as well

 get your ship gassed up and loaded—we'll be back here with the all x in about a minute

 and a half."

     With Brandon at the controls and with Czuv at the communicator plate the

 projection flashed toward distant Callisto and the group melted away, each man going

 about his interrupted task.

     "Daddy, take us somewhere—I want to talk to you," Nadia spoke to her father,

 and the director led her and Stevens to his own room.

     "All x, daughter; out with it!" and he bent upon her a quizzical glance, under

 which a fiery blush burned from her throat to her forehead.

     "Dad, I've been thinking a lot since you rescued us, and what we've just heard

 has given me the nerve to say it. Steve, of course, wouldn't dare suggest such a thing

 until we're safely back on Earth, so I will." Her deep brown eyes held his steadily. "All

 those girls got married—why, some of them have babies already—and Steve and I have

 waited for each other so long, daddy! And wane of them love each other the way we do,

 do they, Steve ?"

     "I don't see how they could, sir; and that goes straight across the panel," and he

 bore unflinchingly the piercing gaze of the older man as^ his right arm encircled the girl

 and held her close.

     "Well, why not?" A sudden smile transformed Newton's stern visage. "There are

 three chaplains with the police —a Methodist minister, a Catholic priest, and a Jewish

 rabbi. Also we have on board two full-fledged I-P captains, either of whom is authorized

 to tie matrimonial knots. The means are not lacking—but just how sure are you of

 yourselves ?" and all levity disappeared as he studied the two young faces.

     "Yes, you are sure," he continued after a moment, "just as her mother and I

 were—and are. It is a drawback that she cannot be here with you, but it may be a long

 time before we can return to Tellus, and you have indeed waited long. But, on the other

 hand, I do not know quite what to think of having a bride aboard a war-vessel . . ."

     "Oh thanks, Daddy, you're just a perfectly wonderful old darling!" Nadia

 exclaimed, as she threw her arms rapturously around his neck. "And this isn't a warship

 at all— you know perfectly well that it's a research laboratory, and that as soon as the

 Navy gets here you won't let it fight a bit more, because such scientists can't be allowed

 to risk themselves! And also, you're forgetting that whole flock of women and babies

 that are coming out here just as fast as they can get themselves ready. So get going,

 daddy old dear, and let's do things! Steve's a Quaker and we're Presbyterians, so none

 of the chaplains will do at all. Besides, I promised Captain King ages ago that he could

 marry me, so go get him and we'll do it now. Bill can be my bridesmaid, you'll give me

 away, and Steve can have the other two of his Big Three for best men. I'm off to hunt up

 the flimsiest, fussiest white dress I can find in my trunks. Let's go!"

     "Mr. Newton." Stevens spoke thoughtfully as Nadia darted away. "You said

 something about her mother. I didn't want to say anything to raise false hopes while she

 was here, but I've got an idea. Let's meet in Brandon's room instead of here. We can

 send code to Tellus easily enough on our ultra-wave, and we may be able to fake up

 something on vision."

     A few minutes later the Big Three were in Brandon's private study; staring intently

 into a screen upon which played flickering, flashing lights, while the black-haired

 physicist manipulated micrometer dials in infinitesimal arcs.

     "Once more, Mac," Brandon directed. "Pretty near had 'em that time. We're

 stretching this projector about six hundred percent, but we've got to make this

 connection. Can't you coax just a few more amps out of those secondaries?"

     "I can not!" The voice of the first assistant snapped from the speaker. "I'm

 overloading now so badly that my plates are getting hot—if I hold this voltage much

 longer the whole secondary bank is going out. All x—you're on zero!"

     "All x!'" Flashing and waning, the lights upon the screen formed fleeting, shifting,

 nebulous images of a relay station upon distant Earth; but the utmost power of the

 transmitting fields could neither steady the image nor hold it.

     "Back off, Mac," Brandon instructed. " 'Fraid we can't hold 'em direct—no use

 blowing a bank of tubes. We'll try relaying through Mars—we can hold 'em there, I think.

 It'll mush up reception some, but it'll probably be better than direct, at that. Point oh five

 three six . . . all x—shoot!"

     Brandon's relay station upon Mars was finally raised and held, and a corps of

 keenly-interested engineers there made short work of the Earth-Mars linkage. Soon the

 screen glowed with the picture of the transmitter-room of the Terrestrial station, and

 while the three men were waiting for Mrs. Newton to be called to her own television set

 the door behind them opened. Nadia and her escorts entered the room—but Stevens'

 eyes saw only the entrancing vision of loveliness that was his bride. Dressed in a

 clinging white gown of shimmering silk, her hair a golden blonde corona, sweetly curved

 lips slightly parted and wide eyes eloquent, she paused momentarily as Stevens came

 to his feet and stared at her, his very heart in his eyes.

     "You never saw me in a dress before—do you like me, Steve?"

     "Like you!" Gray eyes and brown, deep with wonder and with love, met and held

 as, unheeding the presence of their friends, they went into each other's arms in a

 coalescence as inevitable and as final as Fate itself.

     "Hi, Nadia old dear!" and "Daughter, from what I can see of my son-in-law, I

 believe that he may do," came together from the speaker. Nadia tore herself from

 Stevens' embrace, to see upon the lambent screen the happily smiling faces of her

 mother and sister.

     "Mother! Claire! Wonderful! Oh, you three wonderworkers !" She addressed

 simultaneously the distant Terrestrials and the scientists at her side, while broken

 exclamations, punctuated by ominous, crackling snaps, came from the laboring

 amplifier.

     "Sorry to interrupt," MacDonald's voice broke in, "but you'll have to hurry it up.

 Alcantro and Fedanzo are doing their best, but every plate in my secondary bank's red

 hot, and you could fry an egg on any one of my transformers. Even my primaries are

 running hot. She won't hold together five minutes longer!"

     Captain King opened his book, and in that small steel room, unadorned save for

 stack upon stack of book-cases, the brief but solemn ceremony joining two young lives

 was read—its solemnity only intensified by its unique accompaniment. For from

 Brandon at the primary controls, through the power-room of the Sirius and the relay-

 station upon Mars, to the immense Inter-Planetary transmitter upon Earth, the greatest

 radio and television engineers of two planets were fighting overdriven equipment, trying

 to hold an almost impossible connection, in order that Nadia Newton's mother and sister

 might be present at her wedding, hundreds of millions of miles distant in space!

     "I pronounce you man and wife. Whom God hath joined together let no man put

 asunder." The sacred old ritual ended and Captain King picked up the bride in his great

 arms as though she were a baby, kissed her vigorously, and set her down in front of the

 transmitter. In the midst of the joyous confusion that ensued, a tearing, rattling crash

 came from the speaker and the screen went blank.

     "Damnation!" lamented MacDonald from the power room. "I knew they'd blow!

 There goes my whole secondary bank—eight perfectly good ten-nineteens all shot to . .

 ."

     " 'Stoo bad, but it couldn't be helped—they went in a good cause," interrupted

 Brandon. "I'll come down and help clean up the mess."

     Leaving the bridal party, he made his way rapidly to the power room, where he

 found MacDonald and the two Martians inspecting the smoking remains of what had

 been the secondary bank of their powerful ultra-transmitter. Spare parts in abundance

 were on hand, and it was not long until the damaged section was as good as new.

     "Now to try her out," Brandon announced. "We want to give her a good workout,

 but there's no use trying the I-P stations any more—they're altogether too hard to

 handle at this range. Czuv said something about an unknown race of monstrosities at

 the south pole of Jupiter—let's try it on them for a while."

     He flung the field of force out into space, as responsive to his will as a well-

 trained horse, and guided it toward the southern limb of that gigantic world. Down and

 down the projection plunged, through mile after mile of reeking, steaming fog,

 impenetrable to Earthly eyes. Finally it came to rest upon the surface, hundreds of feet

 deep in a lush, dank, tropical jungle, and Brandon plugged into the Venerian room.

     "Kenor? We've got a lot of use for you, if you can come down here for a while . . .

 thanks a lot." He turned to the Martians. "Luckily, we've got a couple of infra-red

 transformers aboard, so we won't have to build one. You fellows might break one out

 and shunt it onto this circuit while Dol Kenor is hunting up something for us to look at.

     "Hi, old Infra-Eyes!" he went on, as the Venerian scientist waddled into the room

 in his bulging space-suit. "We've got something here that's right down your alley. Want

 to see what you can see?"

     "Ah, a beautiful scene!" exclaimed Dol Kenor, after one glance into the plate. "It

 is indeed a relief, after all this coldness and glare, to see such a soft, warm landscape

 —even though I have never expected to behold quite such a violent bit of jungle," and

 under his guidance the projection flashed over hundreds of miles of territory. To the

 eyes of the Terrestrials the screen revealed only a blank, amorphous grayness, through

 which at times there shot lines and masses of vague and meaningless form; but the

 Venerian was very evidently seeing and enjoying many and diverse scenes.

     "There, I think, is what you wish to see first," he announced, as he finally

 steadied the controls, and Brandon cut in upon the shunting screen the infra-red

 transformer. This device, developed long before to render possible the use of Terrestrial

 eyes in the opaque atmosphere of Venus, stepped up the fog-piercing long waves into

 the frequencies of light capable of affecting the Earthly retina. Instantly th6 dull gray

 blank of the shunting screen became transformed into a clear and colorful picture of the

 great city of the Jovians of the South.

     "Great Cat!" Brandon exclaimed. " 'Flying fortresses' is right! They're in war

 formation, too, or I'm a polyp! We've got to watch this, Mac, all of it, and watch it close—

 it's apt to have a big bearing on what we'll have to do, before they get done. Better we

 rig up another set, and put a relay of observers on this job!"
 CHAPTER 11

The Vorkcul-Hexan War

 The city of the Vorkuls, was an immense seven-pointed star. At its center, directly upon

 the south pole of Jupiter, rose a tremendous shaft—its cross section likewise a tapering

 seven-pointed star—which housed the directing intelligences of the nation. Radiating

 from the seven cardinal points of the building were short lanes leading to star-shaped

 open plots, from which in turn branched out ways to other stellate areas; ways reaching,

 after many such steps, to the towering inner walls of the metropolis. The outer walls, still

 loftier and even more massive ramparts of sullen gray-green metal, formed a seamless,

 jointless barrier against an utterly indescribable foe; a barrier whose outer faces

 radiated constantly a searing, coruscating green emanation. Metal alone could not long

 have barred that voracious and implacably relentless enemy, but against that lethal

 green emanation even that ravening Jovian jungle could not prevail, but fell back,

 impotent. Writhing and crawling, loathsomely palpitant with an unspeakable exuberance

 of foul and repellant vigor possible only to such meteorological conditions as obtained

 there, it threw its most hideously prolific growths against that radiant wall in vain.

     The short, zig-zag lanes, the ways, and the seven-pointed areas were paved with

 a greenish glass. This pavement was intended solely to prevent vegetable growth and

 carried no traffic whatever, since few indeed of the Vorkuls have ever been earthbound

 and all traffic was in the air. The principal purpose of the openings was to separate and

 thus to render accessible by air the mighty buildings which, level upon level, towered

 upward, with airships hovering at or anchored to doorways and entrances at every level.

 Buildings, entrances, everything visible—all replicated, reiterated, repeated infinite

 variations in the one theme, that of the septenate stelliform.

     Color ran riot; masses varied from immense blocks of awe inspiring grandeur to

 delicate tracery of sheerest gossamer ; lights flamed and flared in wide bands and in

 narrow, flashing pencils—but in all, through all, over all, and dominating all was the

 Seven-Pointed Star.

     In and almost filling the space, at least a mile in width, between the inner and the

 outer walls were huge, seven-sided structures—featureless, squat, forbidding

 heptagons of dull green metal. Nothing living was to be seen in that space. Its pavement

 was of solid metal and immensely thick, and that metal, as well as that of the walls, was

 burned and blackened and seared as though by numberless exposures to intolerable

 flame. In a lower compartment of one of these enormous heptagons Vortel Kromodeor,

 First Projector Officer, rested before a gigantic and complex instrument board. He was

 at ease—his huge wings folded, his sinuous length coiled comfortably in slack loops

 about two horizontal bars. But at least one enormous, extensible eye was always

 pointed toward the board, always was at least one nimble and bat-like ear cocked

 attentively in the direction of the signal panel.

     A whistling, shrieking ululation rent the air and the officer's coils tightened as he

 reared a few feet of his length upright, shooting out half a dozen tentacular arms to

 various switches and controls upon his board, while throughout the great heptagon

 hundreds of other Vorkuls sprang to attention at their assigned posts of duty. As the

 howling wail came to a climax in a blast of sound Kromodeor threw over a lever, as did

 every other projector officer in every other heptagon, and there was made plain to any

 observer the reason for the burns and scars in the tortured space between the lofty

 inner and outer walls of Vorkulia. For these heptagons were the monstrous flying

 fortresses which Czuv had occasionally seen from afar, as they went upon some

 unusual errand above the Jovian banks of mist, and which Brandon was soon to see in

 his visiray screen. The seared and disfigured metal of the pavement and walls was

 made so by the release of the furious blasts of energy necessary to raise those untold

 thousands of tons of mass against the attraction of Jupiter, more than two and a half

 times the gravity of our own world! Vast volumes of flaming energy shrieked from the

 ports. Wave upon wave, flooding the heptagons, it dashed back and forth upon the

 heavy metal between the walls. As more and more of the inconceivable power of those

 Titanic generators was unleashed, it boiled forth in a devastating flood which, striking

 the walls, rebounded and leaped vertically far above even those mighty ramparts. Even

 the enormous thickness of the highly conducting metal could not absorb all the energy

 of that intolerable blast, and immediately beneath the ports new seven-pointed areas of

 disfigurement appeared as those terrific flying fortresses were finally wrenched from the

 ground and hurled upward.

     High in the air, another signal wailed up and down a peculiar scale of sound and

 the mighty host of vessels formed smoothly into symmetrical groups of seven. Each

 group then moved with mathematical precision into its allotted position in a complex

 geometrical formation—a gigantic, seven-ribbed, duplex cone in space. The flagship

 flew at the apex of this stupendous formation; behind, and protected by, the full power

 of the other floating citadels of the forty nine groups of seven. Due north the amazing

 armada sped in rigorous alignment, flying along a predetermined meridian— due north!

     At the end of his watch Kromodeor relinquished his board to the officer relieving

 him and shot into the air, propelled by the straightening of the powerful coils of his

 snake-like body and tail. Wings half spread, lateral and vertical ruddering fins outthrust,

 he soared across the room toward a low opening. Just before they struck the wall upon

 either side of the doorway the great wings snapped shut, the fins retracted, and the long

 and heavy body struck the floor of the passage without a jar. With a wriggling,

 serpentine motion he sped like a vibrant arrow along the hall and into a wardroom.

 There, after a brief glance around the room, he coiled up beside a fellow officer who

 with one eye was negligently reading a scroll held in three or four hands; while with

 another eye, poised upon its slender pedicle, he watched a moving picture upon a

 television screen.

     "Hello, Kromodeor," Wixill, Chief Power Officer greeted the newcomer in the

 wailing, hissing language of the Vorkuls. He tossed the scroll into the air, where it

 instantly rolled into a tight cylinder and shot into an opening in the wall of the room.

 "Glad to see you. Books and shows are all right on practice cruises, but I can't seem to

 work up much enthusiasm about such things now."

     Kromodeor elevated an eye and studied the screen, upon which, to the

 accompaniment of whistling, shrieking sound, whirled and gyrated an interlacing group

 of serpentine forms.

     "A good show, Wixill," the projector officer replied, "but nothing to hold the

 attention of men engaged in what we are doing. Think of it! After twenty years of

 preparation—two long lifetimes—and for the first time in our history, we are actually

 going to war!"

     "I have thought of it at length. It is disgusting. Compelled to traffic with an alien

 form of life! Were it not to end in the extinction of those unspeakable hexans, it would be

 futile to the point of silliness. I cannot understand them at all. There is ample room upon

 this planet for all of us. Our races combined are not using one seven-thousandth of its

 surface. You would think that they would shun all strangers. Yet for ages have they

 attacked us, refusing to let us alone, until finally they forced us to prepare means for

 their destruction. They seem as senselessly savage as the jungle growths, and, but for

 their very evident intelligence, one would class them as such. You would think that,

 being intelligent, and being alien to us, they would not have anything to do with us in

 any way, peacefully or otherwise. However, their intrusions and depredations are about

 to end."

     "They certainly are. Vorkulia has endured much—too much—but I am glad that

 our forefathers did not decide to exterminate them sooner. If they had, we could not

 have been doing this now."

     "There speaks the rashness of youth, Kromodeor. It is a violation of all our

 instincts to have any commerce with outsiders, as you will learn as soon as you see one

 of them. Then, too, we will lose heavily. Since we have studied their armaments so long,

 and have subjected every phase of the situation to statistical analysis, it is certain that

 we are to succeed—but you also know at what cost."

     "Two sevenths of our force, with a probable error of one in seven," replied the

 younger Vorkul. "And because that figure cannot be improved within the next seven

 years and because of the exceptional weakness of the hexans due to their

 unexpectedly great losses upon Callisto, we are attacking at this time. Their spherical

 vessels are nothing, of course. It is in the reduction of the city that we will lose men and

 vessels. But at that, each of us has five chances in seven of returning, which is good

 enough odds—much better than we had in that last expedition into the jungle. But by

 the Mighty Seven, I shall make myself wrap around one hexan, for my brother's sake,"

 and his coils tightened unconsciously. "Hideous, repulsive monstrosities! Creatures so

 horrible should not be allowed to live—they should have been tossed over the wall to

 the jungle ages ago!" Kromodeor curled out an eye as he spoke, and complacently

 surveyed the writhing cylinder of sinuous, supple power that was his own body.

     "Better avoid contact work with them if possible," cautioned Wixill. "You might not

 be able to unwrap, and to touch one of them is almost unthinkable. Speaking of

 wrapping, you know that they are putting on the finals of the contact work in the star this

 evening. Let's watch them."

     They slid to the floor and wriggled away in perfect "step"—undulating along in

 such nice synchronism that their adjacent sides, only a few inches apart, formed two

 waving, rigidly parallel lines. Deep in the lower part of the fortress they entered a large

 assembly room, provided with a raised platform in the center and having hundreds of

 short, upright posts in lieu of chairs; most of which were already taken by spectators.

 The two officers curled their tails comfortably around two of the vacant pillars, elevated

 their heads to a convenient level of sight, and directed each an eye or two upon the

 stage. This was of course heptagonal. Its sides, like those of the mighty flying forts

 themselves, were not straight, but angled inward sufficiently to make the platform a

 seven-pointed star. The edge was outlined by a low rail, and bulwark and floor were

 padded with thick layers of a hard, but smooth and yielding fabric.

     In this star-shaped ring two young Vorkuls were contending for the championship

 of the fleet in a contest that seemed to combine most of the features of wrestling,

 boxing, and bar-room brawling, with no holds barred. Four hands of each of the

 creatures held heavy leather billies, and could be used only in striking with those

 weapons, the remaining hands being left free to employ as the owner saw fit. Since the

 sport was not intended to be lethal, however, the eyes and other highly vulnerable parts

 were protected by metal masks, and the wing ribs were similarly guarded by leathern

 shields. The guiding fins, being comparatively small and extremely tough, required no

 protection.

     "We're just in time," Kromodeor whistled. "The main bout is nicely on. See

 anyone from the flagship? I might stake a couple of korpels that Sintris will paint the

 symbol upon his wing."

     "Most of their men seem to be across the star," Wixill replied, and both beings fell

 silent, absorbed in the struggle going on in the ring.

     It was a contest well worth watching. Wing crashed against mighty wing and the

 lithe, hard bodies snapped and curled this way and that, almost faster than the eye

 could follow, in quest of advantageous holds. Above the shrieking wails of the crowd

 could be heard the smacks and thuds of the eight flying clubs as they struck against the

 leather shields or against tough and scaly hides. For minutes the conflict raged, with no

 advantage apparent. Now the fighters were flat upon the floor of the star, now dozens of

 feet in the air above it, as one or the other sought to gain a height from which to plunge

 downward upon his opponent; but both stayed upon or over the star—to leave its

 boundaries was to lose disgracefully.

     Then, high in air, the visiting warrior thought that he saw an opening and

 grappled. Wings crashed in fierce blows, hands gripped and furiously wrenched. Two

 powerful bodies, tapering smoothly down to equally powerful tails, corkscrewed around

 each other viciously, winding up into something resembling tightly-twisted lamp cord;

 and the two Vorkuls, each helpless, fell to the mat with a crash. Fast as was Zerexi, the

 gladiator from the flagship, Sintris was the merest trifle faster. Like the straightening of a

 twisted spring of tempered steel that long body uncoiled as they struck the floor, and up

 under those shielding wings—an infinitesimal fraction of a second slow in

 interposing—that lithe tail sped. Two lightning loops flashed around the neck of the

 visitor and tightened inexorably. Desperately the victim fought to break that terrible

 strangle hold, but every maneuver was countered as soon as it was begun. Beating

 wings, under whose frightful blows the very air quivered, were met and parried by wings

 equally capable. Hands and clubs were of no avail against that corded cable of sinew,

 and Sintris, his head retracted between his wings and his own hands re-enforcing that

 impregnable covering over his head and neck, threw all his power into his

 tail—tightening, with terrific, rippling surges, that already throttling band about the throat

 of his opponent. Only one result was possible. Soon Zerexi lay quiet, and a violet beam

 of light flared from a torch at the ringside, bathing both contenders. At the flash the

 winner disengaged himself from the loser, and stood by until the latter had recovered

 the use of his paralyzed muscles. The two combatants then touched wing tips in salute

 and flew away together, over the heads of the crowd; plunging into a doorway and

 disappearing as the two officers uncoiled from their "seats" and wriggled out into the

 corridor.

     "Fine piece of contact work," said Wixill, thoughtfully. "I'm glad that Sintris won,

 but I did not expect him to win so easily. Zerexi shouldn't have gone into a knot so early

 against such a fast man."

     "Oh, I don't know," argued Kromodeor. "His big mistake was in that second body

 check. If he had blocked the sixth arm with his fifth, taken out .the fourth and second

 with his third, and then gone in with . . ." and so, quite like two Earthly experts after a

 good boxing match, the friends argued the fine points of the contest long after they had

 reached their quarters.

     Day after day the vast duplex cone of Vorkulian fortresses sped toward the north

 pole of the great planet, with a high and constant velocity. Day after day the complex

 geometrical figure in space remained unchanged; no unit deviating measurably from its

 precise place in the formation. Over rapacious jungles, over geysers spouting hot water,

 over sullenly steaming rivers and seas, over boiling lakes of mud, and high over gigantic

 volcanoes in uninterrupted eruptions of cataclysmic violence the Vorkulian phalanx

 flew—, straight north. The equatorial regions, considerably hotter then the poles, were

 traversed with practically no change in scenery—it was a world of steaming fog, of

 jungle, of hot water, of boiling, spurting mud, and of volcanoes. Not of such mild and

 sporadic volcanic outbreaks as we of green Terra know, but of gigantic primordial

 volcanoes, in terrifyingly continuous performances of frightful intensity. Due north the

 Vorkulian spearhead was hurled, far into the northern hemisphere before the rigorous

 geometrical alignment was altered.

     "All captains, attention!" Finally, in a high latitude, the flagship sent out final

 instructions. "The hexans have detected us, and our long range observers report that

 they are coming to meet us in force. We will now go into the whirl, and proceed with the

 maneuvers exactly as they have been planned. Whirl!"

     At the command each vessel began to pursue a tortuous spiral path. Each group

 of seven circled slowly about its own axis, as though each structure were attached

 rigidly to a radius rod, and at the same time spiraled around the line of advance in such

 fashion that the whole gigantic cone, wide open maw to the fore, seemed to be boring

 its way through the air.

     "Lucky again!" Kromodeor, in the wardroom, turned to Wixill as the two prepared

 to take their respective watches. "It looks as though the first action would come while

 we're on duty. I've got just one favor to ask—if you have to economize on power, let

 Number One alone, will you?"

     "No fear of that," Wixill hissed, with the Vorkulian equivalent of a chuckle. "We

 have abundance of power for all of you projector officers. But don't waste any of it, or I'll

 cut you down five ratings!"

     "You're welcome. When I shine old Number One on any hexan work, one flash is

 all we'll take. See you at supper," and, leaving his superior at the door of the power

 room, Kromodeor wriggled away to his station upon the parallel horizontal bars before

 his panel.

     Making sure that his tail coils were so firmly clamped that no possible lurch or

 shock could throw him out of position, he set an eye toward each of his sighting

 screens, even though he knew that it would be long before those comparatively short

 range instruments would show anything except friendly vessels. Then, ready for any

 emergency, he scanned his one "live" screen—the one upon which were being flashed

 the pictures and reports secured by the high-powered instruments of the observers.

     With the terrific acceleration employed by the hexan spheres, it was not long until

 the leading squadron of fighting globes neared the Vorkulian war-cone. This advance

 guard was composed of the new, high-acceleration vessels. Their crews, with the innate

 blood-lust and savagery of their breed, had not even entertained the thought of

 accommodating their swifter pace to that of the main body of the fleet. These vast, slow-

 moving structures were no more to be feared than those similar ones whose visits they

 had been repulsing for twenty long Jovian years—by the time the slower spheres could

 arrive upon the scene there would be nothing left for them to do. Therefore, few in

 number as were the vessels of the vanguard, they rushed to the attack. In one blinding

 salvo they launched their supposedly irresistible planes of force — dazzling, scintillating

 planes under whose fierce power the studying, questing, scouting fortresses previously

 encountered had fled back southward; cut, beaten, and crippled. These spiraling

 monsters, however, did not pause or waver in their stolidly ordered motion. As the

 hexan planes of force flashed out the dull green metal walls broke into a sparkling green

 radiance, against which the Titanic bolts spent themselves in vain. Then there leaped

 out from the weird brilliance of the walls of the fortresses great shafts of pale green

 luminescence—tractor ray after gigantic tractor ray, which seized upon the hexan

 spheres and drew them ruthlessly into the yawning open end of that gigantic cone.

     Then, in each group of seven, similar great streamers of energy reached out from

 fortress to fortress, until each group was welded into one mighty unit by twenty-one

 such bands of force. The unit formed, a ray from each of its seven component

 structures seized upon a designated sphere, and under the combined power of those

 seven tractors the luckless globe was literally snapped into the center of mass of the

 Vorkulian unit. There seven dully gleaming red pressor rays leaped upon it, backed by

 all the power of seven gigantic fortresses, held rigidly in formation by the unimaginable

 mass of the structures and by their twenty-one prodigious tractor beams. Under that

 awful impact the screens and walls of the hexan spheres were exactly as effective as so

 many structures of the most tenuous vapor. The red glare of the vortex of those beams

 was lightened momentarily by a flash of brighter color, and through the foggy

 atmosphere there may have flamed briefly a drop or two of metal that was only

 liquefied. The red and green beams snapped out, the peculiar radiance died from the

 metal walls, and the gigantic duplex cone of the Vorkuls bored serenely northward—as

 little marked or affected by the episode as is a darting swift who, having snapped up a

 chance insect in full flight, darts on.

     "Great Cat!" Far off in space, Brandon turned from his visiray screen and wiped

 his brow. "Czuv certainly chirped it, Perce, when he called those things flying fortresses.

 But who, what, why, and how? We didn't see any apparatus that looked capable of

 generating or handling those beams—and of course when they got started their screens

 cut us off. Wish we could have made some sense out of their language—like to know a

 few of their ideas— find out whether we can't get on terms with them some way or

 other. Funny-looking wampuses, but they've got real brains. If they have it in mind to

 take us on next, old son, it'll be just . . . too . . . bad!"

     "And then some," agreed Stevens. "They've got something—no fooling. It looks

 like the hexans are going to get theirs, good and plenty, pretty soon—and then what? I'd

 give my left lung and four front teeth for one look at their controls in action."

     "You and me both—'sfunny, the way those green ray-screens stick to the walls,

 instead of being spherical, as you'd expect . . . should think they'd have to radiate from

 a center, and so be spherical," Brandon cogitated. "However, we've got nothing

 corkscrewy enough to go through 'em, so we'll have to stand by. We'll stay inside

 whenever possible, look on from outside when we must, but all the time picking up

 whatever information we can. In the meantime, now that we've got our passengers, old

 Doctor Westfall prescribes something that he says is good for what ails us.

 Distance—lots of distance, straight out from the sun—and I wouldn't wonder if we'd

 better take his prescription."

     The two Terrestrial observers relapsed into silence, staring into their visiray

 plates, searching throughout the enormous volume of one of those great fortresses in

 another attempt to solve the mystery of the generation and propagation of the incredible

 manifestations of energy which they had just witnessed. Scarcely had the search

 begun, however, when the visirays were again cut off sharply—the rapidly-advancing

 main fleet of the hexans had arrived and the scintillant Vorkulian screens were again in

 place.

     True to hexan nature, training and tradition the fleet, hundreds strong, rushed

 savagely to the attack. Above, below, and around the far-flung cone the furious globes

 dashed, attacking every Vorkulian craft viciously with every resource at their command;

 with every weapon known to their diabolically destructive race. Planes of force stabbed

 and slashed, concentrated beams of annihilation flared fiercely through the reeking

 atmosphere, gigantic aerial bombs and torpedoes were hurled with full radio control

 against the unwelcome visitors—with no effect. Bound together in groups of seven by

 the mighty bands of force, the Vorkulian units sailed calmly northward, spiraling along

 with not the slightest change in formation or velocity. The frightful planes and beams of

 immeasurable power simply spent themselves harmlessly against those sparklingly

 radiant green walls—seemingly as absorbent to energy as a sponge is to water, since

 the eye could not detect any change in the appearance of the screens under even the

 fiercest blasts of the hexan projectors. Bombs, torpedoes, and all material projectiles

 were equally futile—they exploded harmlessly in the air far from their objectives, or

 disappeared at the touch of one of those dark, dull-red pressors. And swiftly, but calmly

 and methodically as at a Vorkulian practice drill, the heptagons were destroying the

 hexan fleet. Seven mighty tractors would lash out, seize an attacking sphere, and snap

 it into the center of mass of the unit of seven. There would be a brief flash of dull red, a

 still briefer flare of incandescence, and the impalpable magnets would leap out to seize

 another of the doomed globes. It was only a matter of moments until not a hexan vessel

 remained; and the Vorkulian juggernaut spiraled onward, now at full acceleration,

 toward the hexan stronghold dimly visible far ahead of them—a vast city built around

 Jupiter's northern pole.

     At the controls of his projector, Kromodeor spun a dial with a many-fingered,

 flexible hand and spoke.

     "Wixill, I am being watched again — I can feel very plainly that strange

 intelligence watching everything I do. Have the tracers located him?"

     "No, they haven't been able to synchronize with his wave yet. Either he is using a

 most minute pencil or, what is more probable, he is on a frequency which we do not

 ordinarily use. However, I agree with you that it is not a malignant intelligence. All of us

 have felt it, and none of us senses enmity. Therefore it is not a hexan—it may be one of

 those strange creatures of the satellites, who are, of course, perfectly harmless."

     "Harmless, but unpleasant," returned Kromodeor. "When we get back I'm going

 to find his beam myself and send a discharge along it that will end his spying upon me. I

 do not . . ."

     A wailing signal interrupted the conversation, and every Vorkul in the vast fleet

 coiled even more tightly about his bars, for the real battle was about to begin. The city of

 the hexans lay before them, all her gigantic forces mustered to repel the first real

 invasion of her long and warlike history. Mile after mile it extended, an orderly labyrinth

 of spherical buildings arranged in vast interlocking series of concentric circles—a city of

 such size that only a small part of it was visible, even to the infra-red vision of the

 Vorkulians. Apparently the city was unprotected, having not even a wall. Outward from

 the low, rounded houses of the city's edge there reached a wide and verdant plain,

 which was separated from the jungle by a narrow moat of shimmering liquid— a liquid of

 such dire potency that across it even those frightful growths could neither leap nor

 creep.

     But as the Vorkulian phalanx approached—now shooting forward and upward

 with maximum acceleration, screaming bolts of energy naming out for miles behind

 each heptagon as the full power of its generators was unleashed— it was made clear

 that the homeland of the hexans was far from unprotected. The verdant plain

 disappeared in a blast of radiance, revealing a transparent surface, through which could

 be seen masses of machinery filling level below level, deep into the ground as far as the

 eye could reach; and from the bright liquid of the girdling moat there shot vertically

 upward a coruscantly refulgent band of intense yellow luminescence. These were the

 hexan defenses, heretofore invulnerable and invincible. Against them any ordinary war-

 craft, equipped with ordinary weapons of offense, would have been as pitifully impotent

 as a naked baby attacking a battleship. But now those defenses were being challenged

 by no ordinary craft; it had taken the mightiest intellects of Vorkulia two long lifetimes to

 evolve the awful engine of destruction which was hurling itself forward and upward with

 an already terrific and constantly increasing speed.

     Onward and upward flashed the gigantic duplex cone, its entire whirling mass

 laced and latticed together into one mammoth unit by green tractor beams and red

 pressors. These tension and compression members, of unheard-of power, made of the

 whole fleet of three hundred forty three fortresses a single stupendous structure—a

 structure with all the strength and symmetry of a cantilever truss! Straight through that

 wall of yellow vibrations the vast truss drove, green walls flaming blue defiance as the

 absorbers overloaded: its doubly-braced tip rearing upward, into and beyond the

 vertical, as it shot through that searing yellow wall. Simultaneously from each heptagon

 there flamed downward a green shaft of radiance, so that the whole immense circle of

 the cone's mouth was one solid tractor beam, fastening upon and holding in an

 unbreakable grip mile upon mile of the hexan earthworks.

     Practically irresistible force and supposedly immovable object! Every loose article

 in every heptagon had long since been stored in its individual shock-proof compartment,

 and now every Vorkul coiled his entire body in fierce clasp about mighty horizontal bars:

 for the entire kinetic energy of the untold millions of tons of mass comprising the cone,

 at the terrific measure of its highest possible velocity, was to be hurled upon those

 unbreakable linkages of force which bound the trussed aggregation of Vorkulian

 fortresses to the deeply-buried intrenchments of the hexans. The gigantic composite

 tractor beam snapped on and held. Inconceivably powerful as that beam was, it

 stretched a trifle under the incomprehensible momentum of those prodigious masses of

 metal, almost halted in their terrific flight. But the war-cone was not quite halted; the

 calculations of the Vorkulian scientists had been accurate. No possible artificial

 structure, and but few natural ones — in practice maneuvers entire mountains had been

 lifted and hurled for miles through the air—could have withstood the incredible violence

 of that lunging, twisting, upheaving impact. Lifted bodily by that impalpable hawser of

 force and cruelly wrenched and twisted by its enormous couple of angular momentum,

 the hexan works came up out of the ground as a waterpipe comes up in the teeth of a

 power shovel. The ground trembled and rocked and boulders, fragments of concrete

 masonry, and masses of metal flew in all directions as that city-encircling conduit of

 diabolical machinery was torn from its bed.

     A portion of that conduit fully thirty miles in length was in the air, a twisted,

 flaming inferno of wrecked generators, exploding ammunition, and broken and short-

 circuited high-tension leads before the hexans could themselves cut it and thus save the

 remainder of their fortifications. With resounding crashes the structure parted at the

 weakened points, the furious upheaval stopped, and, the tractor beams shut off, the

 shattered, smoking, erupting mass of wreckage fell in clashing, grinding ruin upon the

 city.

     The enormous duplex cone of the Vorkuls did not attempt to repeat the

 maneuver but divided into two single cones, one of which darted toward each point of

 rupture. There, upon the broken and unprotected ends of the hexan cordon their points

 of attack lay: theirs the task to eat along that annular fortress, no matter what the

 opposition might bring to bear —to channel in its place a furrow of devastation until the

 two cones, their work complete, should meet at the opposite edge of the city. Then what

 was left of the cones would separate into individual heptagons, which would so

 systematically blast every hexan thing into nothingness as to make certain that never

 again would they resume their insensate attacks upon the Vorkuls. Having counted the

 cost and being grimly ready to pay it, the implacable attackers hurled themselves upon

 their objectives.

     Here were no feeble spheres of space, commanding only the limited energies

 transmitted to their small receptors through the ether. Instead there were all the

 offensive and defensive weapons developed by hundreds of generations of warrior-

 scientists; wielding all the incalculable power capable of being produced by the massed

 generators of a mighty nation. But for the breach opened in the circle by the irresistible

 surprise attack, they would have been invulnerable and, hampered as they were by the

 defenseless ends of what should have been an endless ring, the hexans took heavy toll.

     The heptagons, massive and solidly braced as they were, and anchored by

 tractor beams as well, shuddered and trembled throughout their mighty frames under

 the impact of fiercely-driven pressors. Sullenly radiant green wall-screens flared brighter

 and brighter as the Vorkulian absorbers and dissipators, mighty as they were, continued

 more and more to overload; for there were being directed against them beams from the

 entire remaining circumference of the stronghold. Every deadly frequency and

 emanation known to the fiendish hexan intellect, backed by the full power of the city,

 was poured out against the invaders in sizzling, shrieking bars, bands, and planes of

 frenzied incandescence. Nor was vibratory destruction alone. Armor-piercing projectiles

 of enormous size and weight were hurled—diamond-hard, drill-headed projectiles which

 clung and bored upon impact. High-explosive shells, canisters of gas, and the frightful

 aerial bombs and radio-dirigible torpedoes of highly scientific war—all were thrown with

 lavish hand, as fast as the projectors could be served. But thrust for thrust, ray for ray,

 projectile for massive projectile, the Brobdingnagian creations of the Vorkuls gave back

 to the hexans.

     The material lining of the ghastly moat was the only substance capable of

 resisting the action of its contents, and now, that lining destroyed by the uprooting of the

 fortress, that corrosive, brilliantly mobile liquid cascaded down into the trough and

 added its hellish contribution to the furious scene. For whatever that devouring fluid

 touched flared into yellow flame, gave off clouds of lurid, strangling vapor, and

 disappeared. But through yellow haze, through blasting frequencies, through clouds of

 poisonous gas, through rain of metal and through storm of explosive the two cones

 ground implacably onward, their every offensive weapon centered upon the fast-

 receding exposed ends of the hexan fortress. Their bombs and torpedoes ripped and

 tore into the structure beneath the invulnerable shield and exploded, demolishing and

 hurling aside like straws walls, projectors, men, and vast mountains of earth. Their

 terrible rays bored in, softening, fusing, volatilizing metal, short-circuiting connections,

 destroying life far ahead of the point of attack; and, drawn along by the relentlessly

 creeping composite tractor beam, there progressed around the circumference of the

 hexan city two veritable Saturnalia of destruction—uninterrupted, cataclysmic

 detonations of sound and sizzling, shrieking, multi-colored displays of pyrotechnic

 incandescence combining to form a spectacle of violence incredible.

     But the heptagons could not absorb nor radiate indefinitely those torrents of

 energy, and soon one greenishly incandescent screen went down. Giant shells pierced

 the green metal walls, giant beams of force fused and consumed them. Faster and

 faster the huge heptagon became a shapeless, flowing mass, its metal dripping away in

 flaming gouts of brilliance; then it disappeared utterly in one terrific blast as some

 probing enemy ray reached a vital part. The cone did not pause nor waver. Many of its

 component units would go down, but it would go on—on and on until every hexan trace

 had disappeared or until the last Vorkulian heptagon had been annihilated.

     In one of the lowermost heptagons, one bearing the full brunt of the hexan

 armament, Kromodeor reared upright as his projector controls went dead beneath his

 hands. Finding his communicator screens likewise lifeless, he slipped to the floor and

 wriggled to the room of the Chief Power Officer, where he found Wixill idly fingering his

 controls.

     "Are we out?" asked Kromodeor, tersely.

     "All done," the Chief Power Officer calmly replied. "We have power left, but we

 cannot use it, as they have crushed our screens and are fusing our outer walls. Two out

 of seven chances, and we drew one of them. We are still working on the infra band,

 over across on the Second's board, but we won't last long . . ."

     As he spoke the mighty fabric lurched under them, and only their quick and

 powerful tails, darting in lightning loops about the bars, saved them from being battered

 to death against the walls as the heptagon was hurled end over end by a stupendous

 force. With a splintering crash it came to rest upon the ground.

     "I wonder how that happened ? They should have rayed us out or exploded us,"

 Kromodeor pondered. The Vorkuls, with their inhumanly powerful, sinuous bodies, were

 scarcely affected by the shock of that frightful fall.

     "They must have had a whole battery of pressors on us when our greens went

 out—they threw us half-way across the city, almost into the gate we made first," Wixill

 replied, studying the situation of the vessel in the one small screen still in action. "We

 aren't hurt very badly—only a few holes that they are starting to weld already. When the

 absorber and dissipator crews get them cooled down enough so that we can use power

 again, we'll go back."

     But they were not to resume their place in the attack. Through the holes in the

 still-glowing walls hexan soldiery were leaping in steady streams, fighting with the

 utmost savagery of their bloodthirsty natures, urged on by the desperation born of the

 knowledge of imminent defeat and total destruction. Hand-weapons roared, flashed,

 and sparkled; heavy bars crashed and thudded against crunching bones; mighty bodies

 and tails whipped crushingly about six-limbed forms which wrenched and tore with

 monstrously powerful hands and claws. Fiercely and valiantly the Vorkuls fought, but

 they were outnumbered by hundreds and only one outcome was possible.

     Kromodeor was one of the last to go down. Weapons long since exhausted, he

 unwrapped his deadly coils from about a dead hexan and darted toward a store-room,

 only to be cut off by a horde of enemies. Throwing himself down a vertical shaft, he flew

 toward a tiny projector-locker in the lowermost part of one of the great star's points, the

 hexans in hot pursuit. He wrenched the door open, and even while searing planes of

 force were riddling his body he trained the frightful weapon he had sought. He pressed

 the contact, and a burst of intolerable flame swept the entire passage clear of life.

 Weakly he struggled to go out into the aisle, but his muscles refused to do the bidding of

 his will and he lay there, twitching feebly.

     In the power room of the heptagon a hexan officer turned fiercely to another, who

 was offering advice.

     "Vorkuls? Bah!" he snarled, viciously. "Our race is finished. Die we must, but we

 shall take with us the one enemy who above all others needs destruction!" and he

 hurled the captured Vorkulian fortress into the air.

     As the heptagon lurched upward the massive door of a lower projector locker

 clanged shut and Kromodeor collapsed in a corner, his consciousness blotted out.

                         * * * * *

     "Well, that certainly tears it! That's a . . . I . . ." Stevens' ready vocabulary failed

 him and he turned to Brandon, who was still staring narrow-eyed into the plate,

 watching the destruction of the hexan city.

     "They've got something, all x—you've got to hand it to 'em," Brandon replied.

 "Here we thought we knew something about forces and physical phenomena in

 general—and those birds've forgotten more than we ever will know. Just one of those

 things could take the whole I-P fleet, armed as we are now, any morning before

 breakfast, just for setting-up exercises. We've got to do something about it—but what ?"

     "It's by me—you tell 'em. There may be an out somewhere, but I don't see it,"

 and Stevens' gloomy tone matched his words.

     Highly trained scientists both, they had been watching that which transcended all

 the science of the inner planets and knew themselves outclassed immeasurably.

     "Only one thing to do, as I see it," Brandon cogitated. "That's to keep on going

 straight out, the way we're headed now. We'd better call a council of war, to dope out a

 line of action."
CHAPTER 12

 The Citadel in Space

 For the first time in many days Brandon and Westfall sat at dinner in the main dining

 room of the Sirius. They were enjoying greatly the unaccustomed pleasure of a

 leisurely, formal meal; but still their talk concerned the projection of pure forces instead

 of subjects more appropriate to the table; still their eyes paid more attention to diagrams

 drawn upon scraps of paper than to the diners about them.

     "But I tell you, Quince, you're full of little red ants, clear to the neck!" Brandon

 snorted, as Westfall waved one of his arguments aside. "You must have had help to get

 that far off—no one man could possibly be as wrong as you are. Why, those fields

 absolutely will . . ."

     "Hi, Quincy! Hi, Norman!" a merry voice interrupted. "Fighting, as usual, I see!

 What kind of knights are you, anyway, to rescue us poor damsels in distress, and then

 never even know that we're alive ?" A tall, willowy brunette had seen the two physicists

 as she entered the saloon, and came over to their table, a hand outstretched to each in

 cordial greeting.

     "Ho, Verna!" both men exclaimed, and came to their feet as they welcomed the

 smiling, graceful newcomer.

     "Sit down here, Verna—we have hardly started," West-fall invited, and Brandon

 looked at the girl in assumed surprise as she seated herself in the proffered chair.

     "Well, Verna, it's like this . . ." he began.

     "That's enough!" she broke in. "That phrase always was your introduction to one

 of the world's greatest brainstorms. But I know that this is the first time you have had

 time even to eat like civilized beings, so I'll forgive you this once. Why all the registering

 of amazement, Norman ?"

     "I'm astonished that you aren't being monopolized by some husband or other.

 Surely the officers of the Arcturus weren't so dumb that they'd stand for your still being

 Verna Picketing, were they?"

     "Not dumb, Norman, no. Far from it—just the opposite, in fact. I'm still working for

 my M.R.S. degree, but I haven't succeeded in snaring it yet. You'd be surprised at how

 cagy those officers got after a few of them had been captured. But they are just like any

 other hunted game, I suppose — the antelopes that survive get pretty wild, you know,"

 she concluded, plaintively.

     "Well, that certainly is one tough break for a poor little girl," Brandon

 sympathized. "I could cry a bucket of tears, just thinking about it. Quince, our little Nell,

 here, ain't been done right by. I'm bashful and you're a woman-hater, but between us,

 some way, we've simply got to take steps."

     "You might take longer steps than you think." Verna laughed, her regular, white

 teeth and vivid coloring emphasized by her olive skin and her startling hair, black as

 Brandon's own. "Perhaps I would like a scientist even better than an I-P officer. The

 more I think of it, the surer I am that Nadia Newton had the right idea. I believe that I'll

 catch a physicist, too—either of you would do quite nicely, I think," and she studied the

 two men carefully.

     Westfall, the methodical and precise, had never been able to defend himself

 against Verna Pickering's badinage, but Brandon's ready tongue took up the challenge.

     "Verna, if you really decided to get any living man, he wouldn't stand a chance in

 the world," he declared. "If you've already made up your mind that I'm your meat, I'll

 come down like Davy Crockett's coon. But if either of us will do, that'll give us each a

 fifty-fifty chance to escape your toils. What say we play a game of freeze-out to decide

 it?"

     "Fine, Norman! When shall we play ?"

     "Oh, between Wednesday and Thursday, any week you say," and the two fenced

 on, banteringly but skillfully, with Westfall an appreciative and unembarrassed listener.

     Dinner over, Brandon and Westfall went back to the control room, where they

 found Stevens already seated at one of the master screens.

     "All x, Perce?"

     "All x. The observers report no registrations during the last two watches," and the

 three fell into discussion. Long they talked, studying every angle of the situation

 confronting them; until suddenly a speaker rattled furiously and an enormous, staring

 eye filled both master plates. Brandon's hand flashed to a switch, but the image

 disappeared even before he could establish the full-coverage ray screen.

     "I'm on the upper band—take the lower!" he snapped, but Stevens' projector was

 already in action. Trained minds all, they knew that some intelligence had traced them,

 and all realized that it was of the utmost importance to know what and where that

 intelligence was. Stevens found the probing frequency in his range and they flashed

 their own beam along it, encountering finally one of the monstrous Vorkulian fortresses,

 far from Jupiter and almost directly between them and the planet! Its wall screens were

 in operation, and no frequency at their command could penetrate that neutralizing

 blanket of vibrations.

     "What kind of an eye was that—ever see anything like it, Perce?" Brandon

 demanded.

     "I don't think so, though of course we got only an awfully short flash of it. It didn't

 look like the periscopic eyes that those flying snakes had—looked more like a hexan

 eye, don't you think? Couldn't very well be hexan, though, in that kind of a ship."

     "Don't think so, either. Maybe it's a purely mechanical affair that they use for

 observing. Anyway, old sons, I don't like the looks of things at all. Quince, you're the

 brains of this outfit—shift the massive old intellect into high and tell us what to do."

     Westfall, staring into the eyepiece of the filar micrometer, finished measuring the

 apparent size of the heptagon before he turned toward Stevens and Brandon.

     "It is hard to decide upon a course of action, since anything that we do may prove

 to be wrong," he said, slowly. "However, I do not see that this latest development can

 operate to change the plan we have already adopted; that of running away, straight out

 from the sun. We may have to increase our acceleration to the highest value the women

 and babies can stand. A series of observations of our pursuer will of course be

 necessary to decide that point. It would be useless to go to Titan, for they would be

 powerless to help us. We could not hold their mirror upon either the Sirius or their

 torpedoes against such forces as that fortress has at her command. Then, too, we might

 well be bringing down upon them an enemy who would destroy much of their world

 before he could be stopped. Both Uranus and Neptune are approximately upon our

 present course. Do the Titanians know anything of either of them, Steve?"

     "Not a thing," the computer replied. "They can't get nearly as far as Uranus on

 their power beam—it's all they can do to make Jupiter. They seem to think, though, that

 one or more of the satellites of Uranus or Neptune may be inhabited by beings similar to

 themselves, only perhaps even more so. But considering the difference between what

 we found on the Jovian satellites and on Titan, I'd say that anything might be out

 there—on Uranus, Neptune, Pluto, their satellites, or anywhere else."

     "Cancel Uranus, double that for Neptune and quadruple it for Pluto," Brandon

 commanded. "Realize how far away they are?"

     "That's right, too," agreed Stevens. "Before we got there, with any acceleration

 we can use now, this whole mess will be cleaned up, one way or the other."

     Westfall completed the series of observations and calculated his results. Then,

 with a grave face, he went to consult the medical officers. The women, children, and the

 two Martian scientists were sent to the sick-bay and the acceleration was raised slowly

 to twenty meters per second per second, above which point the physicians declared

 they should not go unless it became absolutely necessary. Then the scientists met

 again—met without Alcantro and Fedanzo, who lay helpless upon narrow hospital

 bunks, unable even to lift their massive arms.

     While Westfall made another series of precise measurements of the super-

 dreadnaught of space so earnestly pursuing them, Brandon stumbled heavily about the

 room, hands jammed deep into pockets, eyes unseeing, emitting clouds of smoke from

 his villainously reeking pipe. The Venerians, lacking Brandon's physical strength and by

 nature quieter of disposition, sat motionless; keen minds hard at work. Stevens sat at

 the calculating machine, absently setting up and knocking down weird and meaningless

 integrals while he also concentrated upon the problem before them.

     "They are still gaining, but comparatively slowly," Westfall finally reported. "They

 seem to be . . ."

     "In that case we may be all x," Brandon interrupted, brandishing his pipe

 vigorously. "We know that they're on a beam—apparently we're the only ones

 hereabout having cosmic power. If we can keep away from 'em until their beam

 attenuates, we can whittle 'em down to our size and then take 'em, no matter how much

 accumulator capacity they've got."

     "But can we keep away from them that long?" asked Dol Kenor, pointedly; and

 his fellow Venerian also had a question to propound:

     "Would it not be preferable to lead them in a wide circle, back to a rendezvous

 with the Space Fleet, which will probably be ready by the time of meeting?"

     "I am afraid that that would be useless," Westfall frowned in thought. "Given

 power, that fortress could destroy the entire Fleet almost as easily as she could wipe

 out the Sirius alone."

     "Kenor's right." Stevens spoke up from the calculator, "You're getting too far

 ahead of the situation. We aren't apt to keep ahead of them long enough to do much

 leading anywhere. The Titanians can hold a beam together from Saturn to Jupiter—why

 can't these snake folks ?"

     "Several reasons," Brandon argued stubbornly. "First place, look at the mass of

 that thing, and remember that the heavier the beam the harder it is to hold it together.

 Second, there's no evidence that they wander around much in space. If their beams are

 designed principally for travel upon Jupiter, why should they have any extraordinary

 range ? I say they can't hold that beam forever. We've got a good long lead, and in spite

 of their higher acceleration I think we'll be able to keep out of range of their heavy stuff.

 If so, we'll describe a circle—only one, a good deal bigger than the one Amonar

 suggested—and meet the fleet at a point where that enemy ship will be about out of

 power."

     Thus for hours the scientists argued, agreeing upon nothing, while the Vorkulian

 fortress crept ever closer. At the end of three days of the mad flight the pursuing

 spaceship was in plain sight, covering hundreds of divisions of the micrometer screens.

 But now the size of the images was increasing with extreme slowness, and the

 scientists of the Sirius watched with strained attention the edges of those glowing green

 pictures. Finally, when the pictured edges were about to cease moving across the

 finely-ruled lines, Brandon cut down his own acceleration a trifle, and kept on

 decreasing it at such a rate that the heptagon still crept up, foot by foot.

     "Hey, what's the big idea?" Stevens demanded.

     "Coax 'em along. If we run away from 'em they'll probably reverse power and go

 back home, won't they? Their beam is falling apart fast, but they're still getting so much

 stuff along it that we couldn't do a thing to stop them. If they think that we're losing

 power even faster than they are, though, they'll keep after us until their beam's so thin

 that they'll just be able to stop on it. Then they'll reverse or else go onto their

 accumulators—reverse, probably, since they'll be a long ways from home by that time.

 We'll reverse, too, and keep just out of range. Then, when we both have stopped and

 are about to start back, their beam will be at its minimum and we'll go to work on

 'em—foot, horse, and marines. Nobody can run us as ragged as they've been doing

 without me doing my damndest to return the compliment. I've got a hunch. If it works we

 can take those birds and take 'em so they'll stay took. We might as well break up— this

 is going to be an ordinary job of piloting for a few days, I think. I'm going up and work

 with the Martians on that hunch. You fellows work out any ideas you want to. Watch 'em

 close, Mac. Keep kidding 'em along, but don't let 'em get close enough to puncture us."

     Everything worked out practically as Brandon had foretold, and a few days later,

 their acceleration somewhat less than Terrestrial gravity, he called another meeting in

 the control room. He came in grinning from ear to ear, accompanied by the two

 Martians, and seated himself at his complex power panel.

     "Now watch the professor closely, gentlemen," he invited. "He is going to cut that

 beam."

     "But you can't," protested Pyraz Amonar.

     "I know you can't, ordinarily, when a beam is tight and solid. But that beam's as

 loose as ashes right now. I told you I had a hunch, and Alcantro and Fedanzo worked

 out the right answer for me. If I can cut it, Quince, and if their screens go down for a

 minute, shoot your visiray into them and see what you can see."

     "All x. How much power are you going to draw ?"

     "Plenty—it figures a little better than four hundred thousand kilofranks. I'll draw it

 all from the accumulators, so as not to disturb you fellows on the cosmic intake. We

 don't care if we do run the batteries down some, but I don't want to hold that load on the

 bus-bars very long. However, if my hunch is right I won't be on that beam five minutes

 before it's cut from Jupiter—and I'll bet you four dollars that you won't see the original

 crew in that fort when you get into it."

     He set upper and lower bands of dirigible projectors to apply a powerful sidewise

 thrust, and the Sirius darted off her course. Flashing a minute pencil behind the huge

 heptagon, Brandon manipulated his tuning circuits until a brilliant spot in space showed

 him that he was approaching resonance with the heptagon's power beam. Micrometer

 dials were then engaged and the delicate tuning continued until the meters gave

 evidence that the two beams were precisely synchronized and exactly opposite in

 phase. Four plunger switches closed, that tiny pilot ray became an enormous rod of

 force, and as those two gigantic beams met in exact opposition and neutralized each

 other a solid wall of blinding brilliance appeared in the empty ether behind the Vorkulian

 fortress. As that dazzling wall sprang into being the sparkling green protection died from

 the walls of the heptagon.

     "Go to it, Quince!" Brandon yelled, but the suggestion was entirely superfluous.

 Even before the wall-screen had died Westfall's beam was trying to get through it, and

 when the visiray revealed the interior of the heptagon the quiet and methodical physicist

 was shaken from his habitual calm.

     "Why, they aren't the winged monsters at all—they're hexans!" he exclaimed.

     "Sure they are." Brandon did not even turn his heavily-goggled eyes from the

 blazing blankness of his own screen. "That was my hunch. Those snakes went about

 things in a business-like fashion. They didn't strike me as being folks who would pull off

 such a wild stunt as trying to chase us clear out of the solar system, but a gang of

 hexans would do just that. Some of them must have captured that ship and, already

 having it in their cock-eyed brains that we were back of what happened on Callisto, they

 decided to bump us off if it was the last thing they ever did. That's what I'd do myself, if I

 were a hexan. Now I'll tell you what's happening back at the home power plant of that

 ship and what's going to happen next. I'm kicking up a horrible row out there with my

 interference, and a lot of instruments at the other end of that beam must be cutting up

 all kinds of didoes, right now. They'll check up on that ship with the expedition, by radio

 and whatnot, and when they find out that it's clear out here—chop! Didn't get to see

 much, did you?"

     "No, they must have switched over to their accumulators almost instantly."

     "Yeah, but if they've got accumulator capacity enough to hold off our entire

 cosmic intake and get back to Jupiter besides, I'm a polyp! We're going to take that

 ship, fellows, and learn a lot of stuff we never dreamed of before. Ha! There goes his

 beam—pay me the four, Quince."

     The dazzling wall of incandescence had blinked out without warning, and

 Brandon's beam bored on through space, unimpeded. He shut it off and turned to his

 fellows with a grin—a grin which disappeared instantly as a thought struck him and he

 leaped back to his board.

     "Sound the high-acceleration warning quick, Perce!" he snapped, and drove in

 switch after switch.

     "Cosmic intake's gone down to zero!" exclaimed Mac-Donald, as the Sirius

 leaped away.

     "Had to cut it—they might shoot a jolt through that band. Just thought of

 something. Maybe unnecessary, but no harm done if . . . it's necessary, all x—we're

 taking a sweet kissing right now. You see, even though we're at pretty long range,

 they've got some horrible projectors, and they were evidently mad enough to waste

 some power taking a good, solid flash at us—and if we hadn't been expecting it, that

 flash would have been a bountiful sufficiency, believe me—Great Cat! Look at that

 meter—and I've had to throw in number ten shunt! The outer screen is drawing five

 hundred and forty thousand!"

     They stared at the meter in amazement. It was incredible, even after they had

 seen those heptagons in action, that at such extreme range any offensive beam could

 be driven with such unthinkable power—power requiring for its neutralization almost the

 full output of the prodigious batteries of accumulators carried by the Sirius! Yet for five,

 ten, fifteen, twenty minutes that beam drove furiously against their straining screens,

 and even Brandon's face grew tense and hard as that frightful attack continued. At the

 end of twenty two minutes, however, the pointer of the meter snapped back to the pin

 and every man there breathed an explosive sigh of relief — the almost unbearable

 bombardment was over; the screen was drawing only its maintenance load.

     "Wow!" Brandon shouted. "I thought they were going to hang to us until we

 cracked, even if it meant that they'd have to freeze to death out here themselves!"

     "It would have meant that, too, don't you think ?" asked Stevens.

     "I imagine so—don't see how they could possibly have enough power left to get

 back to Jupiter if they shine that thing on us much longer. Of course, the more power

 they waste on us the quicker we can take them; but I don't want much more of that

 beam, I'll tell the world—I just about had heart failure before they cut off!"

     The massive heptagon was now drifting back toward Jupiter at constant velocity.

 The hexans were apparently hoarding jealously their remaining power, for their wall

 screens did not flash on at the touch of the visiray. Through unresisting metal the

 probing Terrestrial beams sped, and the scientists studied minutely every detail of the

 Vorkulian

     armament; while the regular observers began to make a detailed photographic

 survey of every room and compartment of the great fortress. Much of the

 instrumentation and machinery was familiar, but some of it was so strange that study

 was useless—days of personal inspection and experiment, perhaps complete

 dismantling, would be necessary to reveal the secrets hidden within those peculiar

 mechanisms.

     "They're trying to save all the power they can—think I'll make them spend some

 more," Brandon remarked, and directed against the heptagon a heavy destructive

 beam. "We don't want them to get back to Jupiter until after we've boarded them and

 found out everything we want to know. Come here, Quince—what do you make of this

 ?"

     Both men stared at the heptagon, frankly puzzled; for the screens of the strange

 vessel did not radiate, nor did the material of the walls yield under the terrible force of

 the beam. The destructive ray simply struck that dull green surface and

 vanished—disappeared without a trace, as a tiny stream of water disappears into a

 partially-soaked sponge.

     "Do you know what you are doing?" asked Westfall, after a few minutes' thought.

 "I believe that you are charging their accumulators at the rate of," he glanced at a meter,

 "exactly thirty one thousand five hundred kilofranks."

     "Great Cat!" Brandon's hand flashed to a switch and the beam expired. "But they

 can't just simply grab it and store it, Quince—it's impossible!"

     "The word 'impossible' in that connection, coming from you, has a queer sound,"

 Westfall said, pointedly, and Brandon actually blushed.

     "That's right, too—we have got pretty much the same idea in our cosmic intake

 fields, but we didn't carry things as far as they have done. Huh! They're flashing us

 again . . . but those thin little beams don't mean anything. They're just trying to make us

 feed them some more, I guess. But we've got to hold them back some way—wonder if

 they can absorb a tractor field?"

     The hexans had lashed out a few times with their lighter weapons, but, finding

 the Sirius unresponsive, had soon shut them off and were stolidly plunging along toward

 Jupiter. Brandon flung out a tractor rod and threw the mass of his cruiser upon it as it

 locked into those sullen green walls. But. as soon as the enemy felt its drag their

 screens flared white, and the massive Terrestrial space-ship quivered in every member

 as that terrific cable of force was snapped.

     "They apparently cannot store up the energy of a tractor," commented Westfall,

 "but you will observe that they have no difficulty in radiating when they care to."

     "Yeah, those two ideas didn't pan out so heavy. There's lots of things not tried

 yet, though. Our next best bet is to get around in front of him and push back. If they can

 wiggle away from more than fifty percent of a pressor, they're really good."

     The pilot maneuvered the Sirius into line, directly between Jupiter and the

 pentagon; and as the driving projectors went into action Brandon drove a mighty

 pressor field along their axis, squarely into the center of mass of the Vorkulian fortress.

 For a moment it held solidly, then, as the screens of the enemy went into action, it

 rebounded and glanced off in sparkling, cascading torrents. But the hexans, with all

 their twisting and turning, could not present to that prodigious beam of force any angle

 sufficiently obtuse to rob it of half its power, and the driving projectors of the pentagon

 again burst into activity as the backward-pushing mass of the Sirius made itself felt. In a

 short time, however, the wall-screens were again cut off—apparently more power was

 required to drive them than they were able to deflect.

     Although even the enormous tonnage of the Terrestrial cruiser was insignificant

 in comparison with the veritable mountain of metal to which she was opposed, so that

 the fiercest thrust of her driving projectors did not greatly affect the monster's progress;

 yet Brandon and his cohorts were well content.

     "It's a long trip back to where they came from, and since they wanted to drift all

 the way, I think they'll be out of power before they get there," Brandon summed up the

 situation. "We aren't losing any power, either, since we are using only a part of our

 cosmic intake."

     In a few hours the struggle had settled down to a routine matter—the Sirius being

 pushed backward steadily against the full drive of her every projector, contesting

 stubbornly every mile of space traversed. Assured that the regular pilots and lookouts

 were fully capable of handling the vessel, the scientists were about to resume their

 interrupted tasks when one of the photographers called them over to look at something

 he had discovered in one of the lowermost and smallest compartments of the heptagon.

 They crowded around the screens, and saw pictured there the winged, snake-like form

 of one of the original crew of the Vorkulian vessel!

     "Dead?" Brandon asked.

     "Not yet," replied the photographer. "He is twitching a little once in a while, but

 you see he's pretty badly cut up."

     "I see he is . . . he must have a lot of vitality to have lasted this long—maybe he'll

 live through it yet. Hold him on the plate, and get his exact measurements." He turned to

 the communicator. "Doctor von Steiffel? Can you come down to the control room a

 minute ? We may want you to operate upon one of these South Jovians after while."

     "Himmel! Es ist der . . ." The great surgeon, bearded and massive, stared into the

 plate, and in his surprise started to speak in his native German. He paused, his long,

 powerful fingers tracing the likeness of the Vorkul upon the plate, then went on: "I would

 like very much to operate, but, not understanding our intentions, he would of course

 struggle. And when that body struggles — schrecklichkeit!" and he waved his arms in a

 pantomime of wholesale destruction.

     "I thought of that—that's why I am talking to you now instead of when we get to

 him, two or three days from now. We'll give you his exact measurements, and a crew of

 mechanics will, under your direction, sink holes in the steel floor and install steel bands

 heavy enough to hold him rigid, from tail-fins to wing-tips. We'll hold him there until we

 can make him understand that we're friends. It is of the utmost importance to save that

 creature's life if possible; because we do not want one of their fortresses launched

 against us— and in any event, it will not do us any harm to have a friend in the City of

 the South."

     "Right. I will also have prepared some kind of a space-suit in which he can be

 brought from his vessel to ours," and the surgeon took the measurements and went to

 see that the "operating table" and suit were made ready for Kromodeor, the sorely

 wounded Vorkul.

     It was not long until the projectors of the heptagon went out and she lay inert in

 space, power completely exhausted. Knowing that the screens of the enemy would

 absorb any ordinary ray, the scientists had calculated the most condensed beam they

 could possibly project, a beam which, their figures showed, should be able to puncture

 those screens by sheer mass action — puncture them practically instantaneously,

 before the absorbers could react. To that end they had arranged their circuits to hurl

 seven hundred sixty five thousand kilofranks—the entire power of their massed

 accumulators and their highest possible cosmic intake—in one tiny bar of superlative

 density, less than one meter in diameter! Everything ready, Brandon shot in the

 prodigious switches that launched that bolt—a bolt so vehement, so inconceivably

 intense that it seemed fairly to blast the very ether out of existence as it tore its way

 along its carefully predetermined line. The intention was to destroy all the control panels

 of the absorber screens; parts so vital that without them the great vessel would be

 helpless, and yet items which the Terrestrials could reconstruct quite readily from their

 photographs and drawings.

     As that irresistible bolt touched the Vorkulian wall-screen the spot of contact

 flared instantaneously through the spectrum and into the black beyond the violet as that

 screen overloaded locally. Fast as it responded and highly conductive though it was, it

 could not handle that frightfully concentrated load. In the same fleeting instant of time

 every molecule of substance in that beam's path flashed into tenuous vapor — no

 conceivable material could resist or impede that stabbing stiletto of energy—and the

 main control panel of the Vorkulian wall-screen system vanished. Time after time, as

 rapidly as he could sight his beam and operate his switches, Brandon drove his needle

 of annihilation through the fortress, destroying the secondary controls. Then, the walls

 unresisting, he cut in the vastly larger, but infinitely less powerful, I-P ray, and with it

 systematically riddled the immense heptagon. Out through the gaping holes in the outer

 walls rushed the dense atmosphere of Jupiter, and the hexans in their massed

 hundreds died.

     The Sirius was brought up beside the heptagon, so that her main air-lock was

 against one of the yawning holes in the green metal wall of the enemy. There she was

 anchored by tractor beams, and the two hundred picked men of the I-P police, in full

 space equipment, prepared to board the gigantic fortress of the void. Brandon sat tense

 at his controls, ready to send his beam ahead of the troopers against any hexans that

 might survive in some as yet unpunctured compartment. General Crowninshield sat

 beside the physicist at an auxiliary board, phones at ears and four infra-red visiray

 plates banked in front of him; ready through light or darkness to direct and oversee the

 attack, no matter where it might lead or how widely separated the platoons might

 become before the citadel was taken.

     The space-line men—the engineers of weightless combat —led the van,

 protected by the projectors of their fellows. Theirs the task to set up ways of rope, along

 which the others could advance. Power drills bit savagely into metal, making holes to

 receive the expanding eyebolts; grappling hooks seized fast every protuberance and

 corner; and at intervals were strung beam-fed lanterns, illuminating brilliantly the line of

 march. Through compartments and down corridors they went, bridging the many gaps

 in the metal through which Brandon's beams had blasted their way; guided by

 Crowninshield along the shortest feasible path toward the little projector room in which

 Kromodeor, the wounded Vorkul, lay. There were so many chambers and

 compartments in the heptagon that it had of course been impossible to puncture them

 all, and in some of the tight rooms were groups of hexans, anxious to do battle. But the

 general's eye led his men, and if such a room lay before them Brandon's frightful beam

 entered it first—and where that beam entered, life departed.

     But the hexans were really intelligent, as has been said. They had had time to

 prepare for what they knew awaited them, and they were rendered utterly desperate by

 the knowledge that, no matter what might happen, their course was run. Their power

 was gone, and even if the present enemy should be driven off, they would float idly in

 space until they died of cold; or, more probably, hurtling toward Jupiter as they were,

 they would plunge to certain death upon its surface as soon as they came within its

 powerful gravitational field. Therefore some fifty of the creatures, who had had space

 experience in their spherical vessels, had spent the preceding days in manufacturing

 space equipment. Let the weight-fiends plan upon detonating magazines of explosives,

 upon laying mines calculated to destroy the invaders, even the vessel itself and all

 within it. Let them plan upon any other such idle schemes, which were certain to be

 foreseen and guarded against by the space-hardened veterans who undoubtedly

 manned that all-powerful and vengeful football of scarred gray metal. Space-fighters

 were they, and as space-fighters would they die; taking with them to their own inevitable

 death a full quota of the enemy.

     Thus it came about that the head of the column of police had scarcely passed a

 certain door when in the room behind it there began to assemble the half-hundred

 space-hounds of the hexans. When the vanguard had approached that room

 Crowninshield had inspected it thoroughly with his infra-red beams. He had found it

 punctured and airless, devoid of life or of lethal devices, and had passed on. But now

 the space-suited warriors of the horde, guided in their hiding by their own visirays, were

 massing there. When the center of the I-P column reached that door it burst open.

 There boiled out into the corridor, into the very midst of the police, fifty demoniacal

 hexans, fighting with berserk fury, ruled by but one impulse—to kill.

     Hand-weapons flashed viciously, tearing at steel armor and at bulging space-

 suits. Space-hooks bit and tore. Pikes and lances were driven with the full power of

 brawny arms. Here and there could be seen trooper and hexan, locked together in

 fierce embrace far from any hand-line — six limbs against four, all ten plied with

 abandon in mortal, hand-to-hand, foot-to-foot combat.

     "Give way!" yelled Crowninshield into the ears of his men. "Epstein, back!

 LeFevre, advance! Get out of block ten—give us a chance to use a beam!"

     As the police fell back out of the designated section of the corridor Brandon's

 beam tore through it, filling it from floor to ceiling with a volume of intolerable energy. In

 that energy walls, doorway, and space-lines, as well as most of the hexans, vanished

 utterly. But the beam could not be used again. Every surviving enemy had hurled

 himself frantically into the thickest ranks of the police and the battle raged fiercer than

 ever. It did not last long. The ends of the column had already closed in. The police filled

 the corridor and overflowed into the yawning chasm cut by the annihilating ray.

 Outnumbered, surrounded upon all sides, above, and below by the Terrestrials, the

 hexans fought with mad desperation to the last man—and to the last man died. And

 even though in lieu of their own highly efficient space-armor they had fought in weak,

 crude, and hastily improvised space-suits which were pitifully inferior to the ray-

 resistant, heavy steel armor of the I-P forces, nevertheless the enormous strength and

 utter savagery of the hexans had taken toll; and when the advance was resumed it was

 with extra lookouts scanning the entire neighborhood of the line of march.

     Since the troops had entered the fortress as close to their goal as possible, it was

 not long until the leading platoon reached the door behind which Kromodeor lay. Tools

 and cylinders of air were brought up, and the engineers quickly fitted pressure

 bulkheads across the corridor. There was a screaming hiss from the valves, the

 atmosphere in that walled-off space became dense, and mechanics attacked with their

 power drills the door of the projector room. It opened, and four husky orderlies rapidly

 but gently encased the long body of the Vorkul in the space-suit built especially to

 receive it. As that monstrous form in its weirdly bulging envelope was guided through

 the air-locks into the Sirius, Crowninshield barked orders into his transmitter and the

 police reformed. They would now systematically scour the fortress, to wipe out any

 hexans that might still be in hiding; to discover and destroy any possible traps or infernal

 machines which the enemy might have planted for their undoing.

     Assured that the real danger to the Sirius was over and that his presence was no

 longer necessary, Brandon turned his controls over to an assistant and went up to the

 Venerian rooms, where von Steiffel and his staff were to operate upon the Vorkul.

 There, in the dense, hot air, but little different now from the atmosphere of Jupiter,

 Kromodeor lay; bolted down to the solid steel of the floor by means of padded steel

 straps. So heavy were the bands that he could not possibly break even one of them; so

 closely were they spaced that he could scarcely have moved a muscle had he tried. But

 he did not try—so near death was he that his mighty muscles did not even quiver at the

 trenchant bite of the surgeon's tools. Von Steiffel and his aides, meticulously covered

 with sterile gowns, hoods, and gloves, worked in most rigidly aseptic style; deftly and

 rapidly closing the ghastly wounds inflicted by the weapons of the hexans.

     "Hi, Brandon," the surgeon grunted as he straightened up, the work completed. "I

 did not use much antiseptic on him. Because of possible differences in blood chemistry

 and in ignorance of his native bacteria, I depended almost wholly upon asepsis and his

 natural resistance. It is a good thing that we did not have to use an anaesthetic. He is in

 bad shape, but if we can feed him successfully, he may pull through."

     "Feed him ? I never thought of that. What d'you suppose he eats ?"

     "I have an idea that it is something highly concentrated, from his anatomy. I shall

 try giving him sugar, milk chocolate, something of the kind. First I shall try maple syrup.

 Being a liquid it is easily administered, and its penetrating odor also may be a help."

     A can of the liquid was brought in and to the amazement of the Terrestrials the

 long, delicate antennae of the Vorkul began to twitch as soon as the can was opened.

 Motioning hastily for silence, von Steiffel filled a bowl and placed it upon the floor

 beneath Kromodeor's grotesque nose. The twitching increased, until finally one dull,

 glazed eye brightened somewhat and curled slowly out upon its slender pedicle, toward

 the dish. His mouth opened sluggishly and a long, red tongue reached out, but as his

 perceptions quickened he became conscious of the strangers near him. The mouth

 snapped shut, the eye retracted, and heaving, rippling surges traversed that powerful

 body as he struggled madly against the unbreakable shackles of steel binding him to

 the floor.

     "Ach, kindlein!" The surgeon bent anxiously over that grotesque but frightened

 head; soothing, polysyllabic German crooning from his bearded lips.

     "Here, let's try this—I'm good on it," Stevens suggested, bringing up the

 Callistonian thought exchanger. All three men donned headsets, and sent wave after

 wave of friendly and soothing thoughts toward that frantic and terrified brain.

     "He's got his brain shut up like a clam!" Brandon snorted. "Open up, guy—we

 ain't going to hurt you! We're the best friends you've got on Earth, if you only knew it!"

     "Himmel, und he iss himself killing!" moaned von Steiffel.

     "One more chance that might work," and Brandon stepped over to the

 communicator, demanding that Verna Pickering be brought at once. She came in as

 soon as the air-locks would permit, and the physicist welcomed her eagerly.

     "This fellow's fighting so he's tearing himself to pieces. We can't make him

 receive a thought, and von Steiffel's afraid to use an anaesthetic. Now it's barely

 possible that he may understand hexan. I thought you wasted time learning any of it, but

 maybe you didn't—see if you can make him understand that we're friends."

     The girl flinched and shrank back involuntarily but forced herself to approach that

 awful head. Bending over, she repeated over and over one harsh, barking syllable. The

 effect of that word was magical. Instantly Kromodeor ceased struggling, an eye curled

 out, and that long, supple tongue flashed down and into the syrup. Not until the last

 sticky trace had been licked from the bowl did his attention wander from the food. Then

 the eye, sparkling brightly now, was raised toward the girl. Simultaneously four other

 eyes arose, one directed at each of the men and the other surveying his bonds and the

 room in which he was. Then the Vorkul spoke, but his whistling, hissing manner of

 speech so garbled the barking sounds of the hexan words he was attempting to utter

 that Verna's slight knowledge of the language was of no use. She therefore put on one

 of the headsets, motioning the men to do the same, and approached Kromodeor with

 the other, repeating the hexan word of friendly import. This time the Vorkul's brain was

 not sealed against the visitors and thoughts began to flow.

     "You've used those things a lot," Brandon turned to Stevens in a quick aside.

 "Can you hide your thoughts ?"

     "Sure—why?"

     "All I can think of is that power system of theirs, and he'd know what we were

 going to do, sure. And I'd better be getting at it anyway. So you can wipe that off your

 mind with a clear conscience—the rest of us will get everything they've got there. Your

 job's to get everything you can out of this bird's brain. All x?"

     "All x."

     "Why, you didn't put yours on!" Verna exclaimed.

     "No, I don't think I'll have time. If I get started talking to him now, I'd be here from

 now on, and I've got a lot of work to do. Steve can talk to him for me — see you later,"

 and Brandon was gone.

     He went directly to the Vorkulian fortress, bare now of hexan life and devoid of

 hexan snares and traps. There he and his fellows labored day after day learning every

 secret of every item of armament and equipment aboard the heptagon.

     "Did you finish up today, Norm?" asked Stevens one evening. "Kromodeor's

 coming to life fast. He's able to wiggle around a little now, and is insisting that we take

 off the one chain we keep on him and let him use a plate, to call his people."

     "All done. Guess I'll go in and talk to him—you all say he's such an egg. With this

 stuff off my mind I can hide it well enough. By the way, what does he eat ?" as the two

 friends set out for the Venetian rooms.

     "Anything that's sweet, apparently, with enough milk to furnish protein. Won't eat

 meat or vegetables at all—von Steiffel says they haven't got much of a digestive tract,

 and I know that they haven't got any teeth. He's already eaten most all the syrup we had

 on board, all of the milk chocolate, and a lot of sugar. But none of us can get any kind of

 a raise out of him at all—not even Nadia, when she fed him a whole box of chocolates."

     "No, I mean what does he eat when he's home ?"

     "It seems to be a sort of syrup, made from the juices of jungle plants, which they

 drag in on automatic conveyors and process on automatic machinery. But he's a funny

 mutt —hard to get. Some of his thoughts are lucid enough, but others we can't make out

 at all—they are so foreign to all human nature that they simply do not register as

 thoughts at all. One funny thing, he isn't the least bit curious about anything. He doesn't

 want to examine anything, doesn't ask us any questions, and won't tell us anything

 about anything, so that all we know about him we found out purely by accident. For

 instance, they like games and sports, and seem to have families. They also have love,

 liking, and respect for others of their own race—but they seem to have no emotions

 whatever for outsiders. They're utterly inhuman—I can't describe it—you'll have to get it

 for yourself."

     "Did you find out about the Callistonians who went to see them ?" , "Negatively,

 yes. They never arrived. They probably couldn't see in the fog, and must have missed

 the city. If they tried to land in that jungle, it was simply just too bad."

     "That would account for everything. So they're strictly neutral, eh? Well, I'll tell

 him 'hi', anyway." Now in the sick-room, Brandon picked up the headset and sent out a

 wave of cheery greeting.

     To his amazement the mind of the Vorkul was utterly unresponsive to his

 thoughts. Not disdainful, not inimical; not appreciative, nor friendly—simply indifferent to

 a degree unknown and incomprehensible to any human mind. He sent Brandon only

 one message, which came clear and coldly emotionless.

     "I do not want to talk to you. Tell the hairy doctor that I am now strong enough to

 be allowed to go to the communicator screen. That is all." The Vorkul's mind again

 became an oblivious maze of unintelligible thoughts. Not deliberately were Kromodeor's

 thoughts hidden; he was constitutionally unable to interest himself in the thoughts or

 things of any alien intelligence.

     "All x, pal." A puzzled, thoughtful look came over Brandon's face as he called von

 Steiffel. "A queer duck, if there ever was one. However, their ships will never bother us,

 that's one good thing; and I think we've got about everything of theirs that we want,

 anyway."

     The surgeon, after a careful examination of his patient, unlocked the heavy collar

 with which he had been restraining the over-anxious Vorkul, and supported him lightly at

 the communicator panel. As surely as though he had used those controls for years

 Kromodeor shot the visiray beam out into space. One hand upon each of the several

 dials and one eye upon each meter, it was a matter only of seconds for him to get in

 touch with Vorkulia. To the Terrestrials the screen was a gray and foggy blank; but the

 manifest excitement shrieking and whistling from the speaker in response to

 Kromodeor's signals made it plain that his message was being received with

 enthusiasm.

     "They are coming," the Vorkul thought, and lay back, exhausted.

     "Just as well that they're coming out here, at that," Brandon commented. "We

 couldn't begin to handle that structure anywhere near Jupiter—in fact, we wouldn't want

 to get very close ourselves, with passengers aboard."

     Such was the power of the Vorkulian vessels that in less than twenty hours

 another heptagon slowed to a halt beside the Sirius and two of its crew were wafted

 aboard.

     They were ushered into the Venerian room, where they talked briefly with their

 wounded fellow before they dressed him in a space-suit, which they filled with air to

 their own pressure. Then all three were lifted lightly into the air, and without a word or a

 sign were borne through the air-locks of the vessel, and into an opening in the wall of

 the rescuing heptagon. A green tractor beam reached out, seizing the derelict, and both

 structures darted away at such a pace that in a few minutes they had disappeared in the

 black depths of space.

     "Well—that, as I may have remarked before, is indisputably and conclusively

 that." Brandon broke the surprised, almost stunned, silence that followed the

 unceremonious departure of the visitors. "I don't know whether to feel relieved at the

 knowledge that they won't bother us, or whether to get mad because they won't have

 anything to do with us."

     He sent the "All x" signal to the pilot, and the Sirius, once more at the

 acceleration of Terrestrial gravity, again bored on through space.
 CHAPTER 13

Spacehounds Triumphant

 Now that the Hexan threat that had so long oppressed the humanity of the Sinus was

 lifted the vessel was filled with relief and rejoicing as the pilot laid his course for Europa.

 Lounges and saloons resounded with noise as police, passengers, and such of the crew

 as were at liberty made merry. The control room, in which were grouped the leaders of

 the expedition and the scientists, was orderly enough, but a noticeable undertone of

 gladness had replaced the tense and somber air it had known so long.

     "Hi, men!" Nadia Stevens and Verna Pickering, arms around each other's waists,

 entered the room and saluted the group gaily before they became a part of it.

     " 'Smatter, girls—tired of dancing already ?" asked Brandon.

     "Oh, no—we could dance from now on," Verna assured him. "But you see, Nadia

 hadn't seen that husband of hers for fifteen minutes, and was getting lonesome. Being

 afraid of all you men, she wanted me to come along for moral support. The real reason I

 came, though," and she narrowed her expressive eyes and lowered her voice

 mysteriously, "is that you two physicists are here. I want to study my chosen victims a

 little longer before I decide over which of you to cast the spell of my fatal charm."

     "But you can't do that," he objected, vigorously. "Quince and I are going to settle

 that ourselves some day— by shooting dice, or maybe each other, or . . ." he broke off,

 listening to an animated conversation going on behind them.

     ". . . just simply outrageous!" Nadia was exclaiming. "Here we saved his life, and

 I fed him a lot of my candy, and we went to all the trouble of bringing their ship back

 here almost to Jupiter for them, and then they simply dashed off without a word of

 thanks or anything! And he always acted as though he never wanted to see or hear of

 any of us again, ever! Why, they don't think straight—as Norman would say it, they're

 full of little red ants! Why, they aren't even human!"

     "Sure not." Brandon turned to the flushed speaker. "They couldn't be, hardly, with

 their makeup. But is it absolutely necessary that all intelligent beings should possess

 such an emotion as gratitude ? Such a being without it does seem funny to us, but I

 can't see that its lack necessarily implies anything particularly important. Keep still a

 minute," he went on, as Nadia tried to interrupt him, "and listen to some real wisdom.

 Quince, you tell 'em."

     "They are, of course, very highly developed and extremely intelligent; but it

 should not be surprising that intelligence should manifest itself in ways quite baffling to

 us human beings, whose minds work so differently. They are, however . . . well,

 peculiar."

     "I won't keep still!" Nadia burst out, at the first opportunity. "I don't want to talk

 about those hideous things any more, anyway. Come on, Steve, let's go up and dance!"

     Crowninshield turned to Verna, with the obvious intention of leading her away,

 but Brandon interposed.

     "Sorry, Crown, but this lady is conducting a highly important psychological

 research, so your purely social claims will have to wait until after the scientific work is

 done."

     "Why narrow the field of investigation?" laughed the girl. "I'd rather widen it,

 myself—I might prefer a general, even to a physicist!"

     They went up to the main saloon and joined the melee there, and after one

 dance with Verna—all he could claim in that crowd of men—Crowninshield turned to

 Brandon.

     "You two seem to know Miss Pickering extraordinarily well. Would I be stepping

 on your toes if I give her a play ?"

     "Clear ether as far as we're concerned." Brandon shrugged his shoulders. "She's

 been kicking around under foot ever since she was knee high to a duck—we gave her

 her first lessons on a slide-rule."

     "Don't be dumb, Norman. That woman's a knockout— a riot—a regular tri-planet

 call-out!"

     "Oh, she's all x, as far as that goes. She's a good little egg, too—not half as

 dumb as she acts—and she's one of the squarest little aces that ever waved a plume;

 but as for playing her—too much like our kid sister."

     "Good—me for her!" and they made their way back down to the control room.

     Stevens, after his one dance with Nadia, had already returned. Brandon and

 Crowninshield found him seated at the calculating machine, continuing a problem which

 already filled several pages of his notebook.

     " 'Smarter, Steve ? So glad to see a calculator and some paper that you can't let

 'em alone?"

     "Not exactly—just had a thought a day or so ago. Been computing the orbit of the

 wreckage of the Arcturus around Jupiter. Think we should salvage it—the upper half, at

 least. It was left intact, you know."

     "Hm . . . m . . . m. That'd be nice, all x. Dope enough ?"

     "Got the direction solid, from my own observations, but the velocity's a pretty

 rough approximation. But after allowing for my probable error it figures an ellipse of low

 eccentricity between the orbits of Io and Europa. Its period is short—about two days."

     "Ain't it wonderful to have a brain?" Brandon addressed the room at large. "The

 kid's clever. Nobody else would've thought of it, except maybe Westfall. Let's see your

 figures. Urn . . . m . . . m. According to that, we're within an hour of it, right now." He

 turned to the pilot and sketched rapidly.

     "Get on this line here, please, and decelerate, so that the stuff'll catch up with us,

 and pass the word to the lookouts. Stevens and I'll take the bow plates.

     " 'Sa good idea you had, egg," he went on to Stevens, as they took their places

 at main and auxiliary ultra-banks. "Lot of plunder in that ship. Instruments, boats, and

 equipment worth millions, besides most of the junk of the passengers — clothes, trunks,

 trinkets, and what-not. You're there, bucko!"

     "Thanks, Chief." They fell silent, watching the instruments carefully, from time to

 time making computations from the readings of the acceleration and flight meters.

     "There she is!" An alarm bell had finally sounded, the ultra-lights had flared out

 into space, and upon both screens there shone out images of the closely clustered

 wreckage of the Arcturus. But both men were more interested just then in the

 mathematics of the recovery than in the vessel itself.

     "Missed it eight minutes of time and eleven divisions on the scale," reported

 Stevens. "Not so good."

     "Not so bad, either—I've seen lots worse." Thus lightly was dismissed a

 mathematical feat which, a few years earlier, before the days of I-P computers, would

 have been deemed worthy of publication in Philosophical Magazine.

     Director Newton was called in, and it was decided that the many smaller

 fragments of the vessel were not worth saving; that its upper half was all that they

 should attempt to tow the enormous distance back to Tellus. The pace of the Sirius was

 adjusted to that of the floating masses, and tractor beams were clamped upon the

 undamaged portion of the derelict and upon the two slices from the nose of the craft. A

 couple of the larger fragments of wreckage were also taken, to furnish metal for the

 repairs which would be necessary. Acceleration was brought slowly up to normal, and

 the battle scarred cruiser of the void, with her heavy burden of inert metal, resumed her

 interrupted voyage toward Europa; the satellite upon which the passengers and crew of

 the ill-fated Arcturus had been so long immured. On she bored through the ether,

 detector screens full out and greenly scintillant Vorkulian wall-screens outlining her

 football shape in weird and ghastly light; unafraid now of any possible surviving space-

 craft of the hexans.

     But if the hexans detected her they made no sign. Perhaps their fleet had been

 destroyed utterly; perhaps it had been impressed upon even their fierce minds that

 those sparkling green screens were not to be molested with impunity. The satellite was

 reached without event, and down into the crater landing shaft the two enormous masses

 of metal dropped.

     Callisto's foremost citizens were on hand to welcome the Terrestrial rescuers,

 and revelry reigned supreme in that deeply buried Europan community. All humanity

 celebrated. The Callistonians rejoiced because they were now freed from the age-old

 oppression of the hexan hordes; because they could once more extend their civilization

 over the Jovian satellites and live again their normal lives upon the surfaces of those

 small worlds. The Terrestrials were almost equally enthusiastic in the reunion that

 marked the end of the long imprisonment of the refugees.

     As soon as the hull of the Arcturus had been warmed sufficiently to permit

 inspection its original passengers were allowed to visit it briefly, to examine and to

 reclaim their belongings. Of course some damage had been done by the cold of

 interplanetary space, but in general everything was as they had left it. Stevens and

 Nadia were among the first permitted aboard. They went first to the control room, where

 Stevens found his bag still lying behind Breckenridge's desk, where he had thrown it

 when he first boarded the vessel. Then they made their way up to Nadia's stateroom,

 which they found in meticulous order and spotless in its cleanliness—there is neither

 dust nor dirt in space, Nadia glanced about the formal little room and laughed up at her

 husband.

     "Funny, isn't it, sweetheart, how little we know what to expect? Just think how

 surprised I would have been, when I left this room, if I had been told that I would have a

 husband before I got back to it!"

     Breckenridge's first thought was for his precious triplex automatic chronometer,

 which he found, of course, " 'way off"—six and three-tenths seconds fast. Having

 corrected the timepiece from that of the Sirius, he began to examine the other delicate

 instruments of his department—and he was easy to find from that time on.

     Overcrowded as the Sirius already was, it was decided that the original

 complement of the Arcturus should occupy their former quarters aboard her during the

 return trip. To this end corps of mechanics set to work upon the salvaged hulk. Heavy

 metal work was no novelty to the Callistonian engineers and mechanics, and the Sirius

 also was well equipped with metal-working machines and men. Thus the prow was

 welded; armored insulating air-breaks were built along the stern, which was the plane of

 hexan cleavage; electrical connections were restored; and lastly, a set of the great

 Vorkulian wall-screen generators, absorbers, and dissipators was installed, with

 sufficient accumulator capacity for their operation. Director Newton studied this

 installation in silence for some time, then went in search of Brandon.

     "I hadn't considered the possibility of being attacked again between here and

 Tellus, but there's always the chance," he admitted. "If you think that there is any

 danger, we will crowd them all into the Sirius. It will not be at all comfortable, but it will

 be better than having any more of us killed."

     "With that outfit they'll be as safe as we will," the scientist assured him. "They can

 stand as much grief as we can. We'll do the fighting for the whole outfit from here, and

 anything we meet will have to take us before they can touch them. So they'd better ride

 it there, where they'll have passengers' accommodations and be comfortable. As to

 danger, I don't know what to expect. They may all be gone and they may not. We're

 going to expect trouble every meter of the way in, though, and be ready for it."

     Everything ready and thoroughly tested, and a stream of power flowing into the

 Arcturus from the cosmic receptors of her sister ship, the passengers and their new

 possessions were moved into their former quarters. There was a brief ceremony of

 farewell, the doors of the airlocks were closed, the careful check-out was gone through,

 and the driving projectors of the Sirius lifted both great vessels up the shaft, slowly and

 easily. And after them, as long as they could be seen, stared the thousands of

 Callistonians who thronged the great shaft's floor. Many of the spectators were not,

 strictly speaking, Callistonians at all. They were really Europans, born and reared in that

 hidden city which was to have been the last stronghold of Callisto's civilization. In that

 throng were hundreds who had never before seen the light of the sun nor any of the

 glories of the firmament, hundreds to whom that brief glimpse was a foretaste of the free

 and glorious life which was soon to be theirs.

     Up and up mounted that powerful tug-boat of space, with her heavy barge, falling

 smoothly upward at normal acceleration. Below her first Europa, then mighty Jupiter,

 became moons growing smaller and smaller. In their stateroom Nadia's supple waist

 writhed in the curve of Stevens' arm as she turned and looked up at him with sparkling

 eyes.

     "Well, big fellow, how does it feel to be out of a job? Or are you going over there

 every day on a tractor beam to work, as Norman suggested ?"

     "Not on your sweet young life!" he exclaimed. "Norm thought he was kidding

 somebody, but it registered zero. It gives me the pip to loaf around when there's a lot of

 work to do, but this is entirely different. Nothing's driving us now, and a fellow's entitled

 to at least one honeymoon during his life. And what a honeymoon this is going to be,

 little spacehound of my heart! Nothing to do but love you all the way from here to Tellus!

 Whoopee !"

     "Oh, there's a couple of other things to do," she reminded him gaily. "You've got

 to smoke a lot of good cigarettes, I must eat a lot of Delray's chocolates, and we both

 really should catch up on eating fancy cookery. Speaking of eating, isn't that the second

 call for dinner? It is!" and they went along the narrow hall toward the elevator. To these

 two the long journey was to seem all too short.

     Long though the voyage was, it was uneventful. The occupants of the two

 vessels were in constant touch with each other by means of the communicators, and

 there was also much visiting back and forth in person. Stevens and Nadia came often to

 the Sirius, and were accompanied frequently by Verna Pickering, who claimed anew her

 ancient right of "kicking around under foot" wherever Brandon and Westfall might

 chance to be—and at such times General Crowninshield was practically certain to

 appear. And upon days when the beautiful brunette did not appear, the commandant

 generally found it necessary to inspect in person something in the Arcturus.

     Day after day passed, and even the new and ultra-powerful detector screens of

 the Sirius remained unresponsive and cold. Day after day the plates before the doubled

 lookouts and observers remained blank. Power flowed smoothly and unfailingly into the

 cosmic receptors, and the products of conversion were discharged with equal

 smoothness and regularity from the forty five gigantic driving projectors. The tractor

 beam held its heavy burden easily and the generators functioned perfectly. And finally a

 planet began to loom up in the stern lookout plates.

     Verna, the irrepressible, was in the control room of the Sirius, quarreling adroitly

 with Brandon and deftly flirting with Crowninshield. Glancing into the control screen she

 saw the planet in its end block, then studied the instruments briefly.

     "We're heading for Mars!" she declared with conviction. "I thought it looked that

 way yesterday, but supposed it must be only apparent—a trick of piloting or something

 about the orbit. I thought of course you were taking us back home—but you can't

 possibly get to Tellus on any such course as this!"

     "Sure not," Brandon replied easily. "Certainly it's Mars. Isn't that where the

 Arcturus started out for? Who ever said we were going to Tellus ? Of course, if any of

 the passengers want to go right back, the IPC will undoubtedly furnish transportation

 gratis. But paste this in your hat, Verna, for future reference—when spacehounds start

 out to go anywhere they go there, even if they have to spend a year or so on plus time

 to do it!"

     Closer and closer they approached the red planet, swinging around in a wide arc

 in order to make their course coincide exactly with the pilot ray of check station Mi4,

 which was now precisely in its scheduled location in space. At the chief pilot's desk in

 the control room of the Arcturus, Breckenridge checked in with the station, then

 calculated rapidly the instant of their touching the specially-built bumper platforms of

 spring steel, hemp, and fiber which awaited them upon the Martian dock of the Inter-

 Planetary Corporation. Within range of the terminal, he plugged into it, waited until the

 tiny light flashed its green message of attention, and reported.

     "IPV Arcturus; Breckenridge, Chief Pilot; trip number forty three twenty nine.

 Checking in—four hundred forty six days, fifteen hours, eleven minutes, thirty eight and

 seven-tenths seconds plus!"

 THE END