"I hate to leave this meeting—it's great stuff" remarked Seaton as he flashed down to the torpedo room at Fenor's command to send recall messages to all outlying vessels, "but this machine isn't designed to let me be in more than two places at once. Wish it were—maybe after this fracas is over we'll be able to incorporate something like that into it."

The chief operator touched a lever and the chair upon which he sat, with all its control panels, slid rapidly across the floor toward an apparently blank wall. As he reached it, a port opened a metal scroll appeared, containing the numbers and last reported positions of all Fenachrone vessels outside the detector zone, and a vast magazine of torpedoes came up through the floor, with an automatic loader to place a torpedo under the operator's hand the instant its predecessor had been launched.

"Get Peg here quick, Mart—we need a stenographer. Till she gets here, see what you can do in getting those first numbers before they roll off the end of the scroll. No, hold it—as you were! I've got controls enough to put the whole thing on a recorder, so we can study it at our leisure."

Haste was indeed necessary for the operator worked with uncanny quickness of hand. One fleeting glance at the scroll, a lightning adjustment of dials in the torpedo, a touch upon a tiny button, and a messenger was upon its way. But quick as he was, Seaton's flying fingers kept up with him, and before each torpedo disappeared through the ether gate there was fastened upon it a fifth-order tracer ray that would never leave it until the force had been disconnected at the gigantic control board of the Norlaminian projector. One flying minute passed during which seventy torpedoes had been launched, before Seaton spoke.

"Wonder how many ships they've got out, anyway? Didn't get any idea from the brain-record. Anyway, Rovol, it might be a sound idea for you to install me some more tracer rays on this board, I've got only a couple of hundred, and that may not be enough—and I've got both hands full."

Rovol seated himself beside the younger man, like one organist joining another at the console of a tremendous organ. Seaton's nimble fingers would flash here and there, depressing keys and manipulating controls until he had exactly the required combination of forces centered upon the torpedo next to issue. He then would press a tiny switch and upon a panel full of red-topped, numbered plungers; the one next in series would drive home, transferring to itself the assembled beam and releasing the keys for the assembly of other forces. Rovol's fingers were also flying, but the forces he directed were seizing and shaping material, as well as other forces. The Norlaminian physicist, set up one integral, stepped upon a pedal, and a new red-topped stop precisely like the others and numbered in order, appeared as though by magic upon the panel at Seaton's left hand. Rovol then leaned back in his seat—but the red-topped stops continued to appear, at the rate of exactly seventy per minute, upon the panel, which increased in width sufficiently to accommodate another row as soon as a row was completed.

Rovol bent a quizzical glance upon the younger scientist, who blushed a fiery red, rapidly set up another integral, then also leaned back in his place, while his face burned deeper than before.

"That is better, son. Never forget that it is a waste of energy to do the same thing twice with your hands and that if you know precisely what is to be done, you need not do it with your hands at all. Forces are tireless, and they neither slip nor make mistakes."

"Thanks, Rovol—I'll bet this lesson will make it stick in my mind, too."

"You are not thoroughly accustomed to using all your knowledge as yet. That will come with practice, however, and in a few weeks you will be as thoroughly at home with forces as I am."

"Hope so, Chief, but it looks like a tall order to me."

Finally the last torpedo was dispatched, the tube closed, and Seaton moved the projection back up into the council chamber, finding it empty.

"Well, the conference is over—besides, we've got more important fish to fry. War has been declared, on both sides, and we've got to get busy. They've got nine hundred and six vessels out, and every one of them has got to go to Davy Jones' locker before we can sleep sound of nights. My first job'll have to be untangling those nine oh six forces, getting lines on each one of them, and seeing if I can project straight enough to find the ships before the torpedoes overtake them. Mart, you and Orlon, the astronomer, had better dope out the last reported positions of each of those vessels, so we'll know about where to hunt for them. Rovol, you might send out a detector screen a few light years in diameter, to be sure none of them slips a fast one over on us. By starting it right here and expanding it gradually, you can be sure that no Fenachrone is inside it. Then we'll find a hunk of copper on that planet somewhere, plate it with some of their own 'X' metal, and blow them into Kingdom Come."

"May I venture a suggestion?" asked Drasnik, the First of Psychology.

"Absolutely—nothing you've said so far has been idle chatter."

"You know, of course, that there are real scientists among the Fenachrone; and you yourself have suggested that while they cannot penetrate the zone of force nor use fifth-order rays, yet they might know about them in theory, might even be able to know when they were being used—detect them, in other words. Let us assume that such a scientist did detect your rays while you were there a short time ago. What would he do?"

"Search me.... I bite, what would he do?"

"He might do any one of several things, but if I read their nature aright, such a one would gather up a few men and women—as many as he could—and migrate to another planet. For he would of course grasp instantly the fact that you had used fifth-order rays as carrier waves, and would be able to deduce your ability to destroy. He would also realize that in the brief time allowed him, he could not hope to learn to control those unknown forces; and with his terribly savage and vengeful nature and intense pride of race, he would take every possible step both to perpetuate his race and to obtain revenge. Am I right?"

Seaton swung to his controls savagely, and manipulated dials and keys rapidly.

"Right as rain, Drasnik. There—I've thrown around them a fifth-order detector screen, that they can't possibly neutralize. Anything that goes out through it will have a tracer slapped onto it. But say, it's been half an hour since war was declared—suppose we're too late? Maybe some of them have got away already, and if one couple of 'em has beat us to it, we'll have the whole thing to do over again a thousand years or so from now. You've got the massive intellect, Drasnik. What can we do about it? We can't throw a detector screen all over the Galaxy."

"I would suggest that since you have now guarded against further exodus, it is necessary to destroy the planet for a time. Rovol and his co-workers have the other projector nearly done. Let them project me to the world of the Fenachrone, where I shall conduct a thorough mental investigation. By the time you have taken care of the raiding vessels, I believe that I shall have been able to learn everything we need to know."

"Fine—hop to it, and may there be lots of bubbles in your think-tank. Anybody else know of any other loop-holes I've left open?"

No other suggestions were made, and each man bent to his particular task. Crane at the star-chart of the Galaxy and Orlon at the Fenachrone operator's dispatching scroll rapidly worked out the approximate positions of the Fenachrone vessels, and marked them with tiny green lights in a vast model of the Galaxy which they had already caused forces to erect in the air of the projector's base. It was soon learned that a few of the ships were exploring quite close to their home system; so close that the torpedoes, with their unthinkable acceleration, would reach them within a few hours. Ascertaining the stop-number of the tracer ray upon the torpedo which should first reach its destination, Seaton followed it from the stop upon his panel out to the flying messenger. Now moving with a velocity many times that of light, it was, of course, invisible to direct vision; but to the light waves heterodyned upon the fifth-order projector rays, it was as plainly visible as though it were stationary. Lining up the path of the projectile accurately, he then projected himself forward in that exact line, with a flat detector-screen thrown out for half a light year upon each side of him. Setting the controls, he flashed ahead, the detector stopping him the instant that the invisible barrier encountered the power-plant of the exploring raider. An oscillator sounded a shrill and rising note, and Seaton slowly shifted his controls until he stood in the control room of the enemy vessel.

The Fenachrone ship, a thousand feet long and more than a hundred feet in diameter, was tearing through space toward a brilliant blue-white star. Her crew were at battle stations, her navigating officers peering intently into the operating visiplates, all oblivious to the fact that a stranger stood in their very midst.

"Well, here's the first one, gang," said Seaton, "I hate like sin to do this—it's altogether too much like pushing baby chickens into a creek to suit me, but it's a dirty job that's got to be done."

As one man, Orlon and the other remaining Norlaminians leaped out of the projector and floated to the ground below.

"I expected that," remarked Seaton. "They can't even think of a thing like this without getting the blue willies—I don't blame them much, at that. How about you, Carfon? You can be excused if you like."

"I want to watch those forces at work. I do not enjoy destruction, but like you, I can make myself endure it."

Dunark, the fierce and bloodthirsty Osnomian prince, leaped to his feet, his eyes flashing.

"That's one thing I never could get about you, Dick!" he exclaimed in English. "How a man with your brains can be so soft—so sloppily sentimental, gets clear past me. You remind me of a bowl of mush—you wade around in slush clear to your ears. Faugh! It's their lives or ours! Tell me what button to push and I'll be only too glad to push it. I wanted to blow up Urvania and you wouldn't let me; I haven't killed an enemy for ages, and that's my trade. Cut out the sob-sister act and for Cat's sake, let's get busy!"

"'At-a-boy, Dunark! That's tellin' 'im! But it's all right with me—I'll be glad to let you do it. When I say 'shoot' throw in that plunger there—number sixty-three."

Seaton manipulated controls until two electrodes of force were clamped in place, one at either end of the huge power-bar of the enemy vessel; adjusted rheostats and forces to send a disintegrating current through that massive copper cylinder, and gave the word. Dunark threw in the switch with a vicious thrust, as though it were an actual sword which he was thrusting through the vitals of one of the awesome crew, and the very Universe exploded around them—exploded into one mad, searing coruscation of blinding, dazzling light as the gigantic cylinder of copper resolved itself instantaneously into the pure energy from which its metal originally had come into being.

Seaton and Dunark staggered back from the visiplates, blinded by the intolerable glare of light, and even Crane, working at his model of the galaxy, blinked at the intensity of the radiation. Many minutes passed before the two men could see through their tortured eyes.

"Zowie! That was fierce!" exclaimed Seaton, when a slowly-returning perception of things other than dizzy spirals and balls of flame assured him that his eyesight was not permanently gone. "It's nothing but my own fool carelessness, too. I should have known that with all the light frequencies in heterodyne for visibility, enough of that same stuff would leak through to make strong medicine on these visiplates—for I knew that that bar weighed a hundred tons and would liberate energy enough to volatilize our Earth and blow the by-products clear to Arcturus. How're you coming, Dunark? See anything yet?"

"Coming along O. K. now, I guess—but I thought for a few minutes I'd been bloody well jobbed."

"I'll do better next time. I'll cut out the visible spectrum before the flash, and convert and reconvert the infra-red. That'll let us see what happens, without the direct effect of the glare—won't burn our eyes out. What's my force number on the next nearest one, Mart?"

"Twenty-nine."

Seaton fastened a detector ray upon stop twenty-nine of the tracer-ray panel and followed its beam of force out to the torpedo hastening upon its way toward the next doomed cruiser. Flashing ahead in its line as he had done before, he located the vessel and clamped the electrodes of force upon the prodigious driving bar. Again, as Dunark drove home the detonating switch, there was a frightful explosion and a wild glare of frenzied incandescence far out in that desolate region of interstellar space; but this time the eyes behind the visiplates were not torn by the high frequencies, everything that happened was plainly visible. One instant, there was an immense space-cruiser boring on through the void upon its horrid mission, with its full complement of the hellish Fenachrone performing their routine tasks. The next instant there was a flash of light extending for thousands upon untold thousands of miles in every direction. That flare of light vanished as rapidly as it had appeared—instantaneously—and throughout the entire neighborhood of the place where the Fenachrone cruiser had been, there was nothing. Not a plate nor a girder, not a fragment, not the most minute particle nor droplet of disrupted metal nor of condensed vapor. So terrific, so incredibly and incomprehensibly vast were the forces liberated by that mass of copper in its instantaneous decomposition, that every atom of substance in that great vessel had gone with the power-bar—had been resolved into radiations which would at some distant time and in some far-off solitude unite with other radiations, again to form matter, and thus obey Nature's immutable cyclic law.

Thus vessel after vessel was destroyed of that haughty fleet which until now had never suffered a reverse and a little green light in the galactic model winked out and flashed back in rosy pink as each menace was removed. In a few hours the space surrounding the system of the Fenachrone was clear; then progress slackened as it became harder and harder to locate each vessel as the distance between it and its torpedo increased. Time after time Seaton would stab forward with his detector screen extended to its utmost possible spread, upon the most carefully plotted prolongation of the line of the torpedo's flight, only to have the projection flash far beyond the vessel's furthest possible position without a reaction from the far-flung screen. Then he would go back to the torpedo, make a minute alteration in his line, and again flash forward, only to miss it again. Finally, after thirty fruitless attempts to bring his detector screen into contact with the nearest Fenachrone ship, he gave up the attempt, rammed his battered, reeking briar full of the rank blend that was his favorite smoke, and strode up and down the floor of the projector base—his eyes unseeing, his hands jammed deep into his pockets, his jaw thrust forward, clamped upon the stem of his pipe, emitting dense, blue clouds of strangling vapor.

"The maestro is thinking, I perceive," remarked Dorothy, sweetly, entering the projector from an airboat. "You must all be blind, I guess—you no hear the bell blow, what? I've come after you—it's time to eat!"

"'At-a-girl, Dot—never miss the eats! Thanks," and Seaton put his problem away, with perceptible effort.

"This is going to be a job, Mart," he went back to it as soon as they were seated in the airboat, flying toward "home." "I can nail them, with an increasing shift in azimuth, up to about thirty thousand light-years, but after that it gets awfully hard to get the right shift, and up around a hundred thousand it seems to be darn near impossible—gets to be pure guesswork. It can't be the controls, because they can hold a point rigidly at five hundred thousand. Of course, we've got a pretty short back-line to sight on, but the shift is more than a hundred times as great as the possible error in backsight could account for, and there's apparently nothing either regular or systematic about it that I can figure out. But.... I don't know.... Space is curved in the fourth dimension, of course.... I wonder if ... hm—m—m." He fell silent and Crane made a rapid signal to Dorothy, who was opening her mouth to say something. She shut it, feeling ridiculous, and nothing was said until they had disembarked at their destination.

"Did you solve the puzzle, Dickie?"

"Don't think so—got myself in deeper than ever, I'm afraid," he answered, then went on, thinking aloud rather than addressing any one in particular:

"Space is curved in the fourth dimension, and fifth-order rays, with their velocity, may not follow the same path in that dimension that light does—in fact, they do not. If that path is to be plotted it requires the solution of five simultaneous equations, each complete and general, and each of the fifth degree, and also an exponential series with the unknown in the final exponent, before the fourth-dimensional concept can be derived ... hm—m—m. No use—we've struck something that not even Norlaminian theory can handle."

"You surprise me." Crane said. "I supposed that they had everything worked out."

"Not on fifth-order stuff—it's new, you know. It begins to look as though we'd have to stick around until every one of those torpedoes gets somewhere near its mother-ship. Hate to do it, too—it'll take six months, at least, to reach the vessels clear across the Galaxy. I'll put it up to the gang at dinner—guess they'll let me talk business a couple of minutes overtime, especially after they find out what I've got to say."

He explained the phenomenon to an interested group of white-bearded scientists as they ate. Rovol, to Seaton's surprise, was elated and enthusiastic.

"Wonderful, my boy!" he breathed. "Marvelous! A perfect subject for years after year of deepest study and the most profound thought. Perfect!"

"But what can we do about it?" asked Seaton, exasperated. "We don't want to hang around here twiddling our thumbs for a year waiting for those torpedoes to get to wherever they're going!"

"We can do nothing but wait and study. That problem is one of splendid difficulty, as you yourself realize. Its solution may well be a matter of lifetimes instead of years. But what is a year, more or less? You can destroy the Fenachrone eventually, so be content."

"But content is just exactly what I'm not!" declared Seaton, emphatically. "I want to do it, and do it now!"

"Perhaps I might volunteer a suggestion," said Caslor, diffidently; and as both Rovol and Seaton looked at him in surprise he went on: "Do not misunderstand me. I do not mean concerning the mathematical problem in discussion, about which I am entirely ignorant. But has it occurred to you that those torpedoes are not intelligent entities, acting upon their own volition and steering themselves as a result of their own ordered mental processes? No, they are mechanisms, in my own province, and I venture to say with the utmost confidence that they are guided to their destinations by streamers of force of some nature, emanating from the vessels upon whose tracks they are."

"'Nobody Holme' is right!" exclaimed Seaton, tapping his temple with an admonitory forefinger. "'Sright, ace—I thought maybe I'd quit using my head for nothing but a hatrack now, but I guess that's all it's good for, yet. Thanks a lot for the idea—that gives me something I can get my teeth into, and now that Rovol's got a problem to work on for the next century or so, everybody's happy."

"How does that help matters?" asked Crane in wonder. "Of course it is not surprising that no lines of force were visible, but I thought that your detectors screens would have found them if any such guiding beams had been present."

"The ordinary bands, if of sufficient power, yes. But there are many possible tracer rays not reactive to a screen such as I was using. It was very light and weak, designed for terrific velocity and for instantaneous automatic arrest when in contact with the enormous forces of a power bar. It wouldn't react at all to the minute energy of the kind of beams they'd be most likely to use for that work. Caslor's certainly right. They're steering their torpedoes with tracer rays of almost infinitesimal power, amplified in the torpedoes themselves—that's the way I'd do it myself. It may take a little while to rig up the apparatus, but we'll get it—and then we'll run those birds ragged—so fast that their ankles'll catch fire—and won't need the fourth-dimensional correction after all."

When the bell announced the beginning of the following period of labor, Seaton and his co-workers were in the Area of Experiment waiting, and the work was soon under way.

"How are you going about this, Dick?" asked Crane.

"Going to examine the nose of one of those torpedoes first, and see what it actually works on. Then build me a tracer detector that'll pick it up at high velocity. Beats the band, doesn't it, that neither Rovol nor I, who should have thought of it first, ever did see anything as plain as that? That those things are following a ray?"

"That is easily explained, and is no more than natural. Both of you were not only devoting all your thoughts to the curvature of space, but were also too close to the problem—like the man in the woods, who cannot see the forest because of the trees."

"Yeah, may be something in that, too. Plain enough, when Caslor showed it to us," said Seaton.

While he was talking, Seaton had projected himself into the torpedo he had lined up so many times the previous day. With the automatic motions set to hold him stationary in the tiny instrument compartment of the craft, now traveling at a velocity many times that of light, he set to work. A glance located the detector mechanism, a set of short-wave coils and amplifiers, and a brief study made plain to him the principles underlying the directional loop finders and the controls which guided the flying shell along the path of the tracer ray. He then built a detector structure of pure force immediately in front of the torpedo, and varied the frequency of his own apparatus until a meter upon one of the panels before his eyes informed him that his detector was in perfect resonance with the frequency of the tracer ray. He then moved ahead of the torpedo, along the guiding ray.

"Guiding it, eh?" Dunark congratulated him.

"Kinda. My directors out there aren't quite so hot, though. I'm a trifle shy on control somewhere, so much so that if I put on anywhere near full velocity, I lose the ray. Think I can clear that up with a little experimenting, though."

He fingered controls lightly, depressed a few more keys, and set one vernier, already at a ratio of a million to one, down to ten million. He then stepped up his velocity, and found that the guides worked well up to a speed much greater than any ever reached by Fenachrone vessels or torpedoes, but failed utterly to hold the ray at anything approaching the full velocity possible to his fifth-order projector. After hours and days of work and study—in the course of which hundreds of the Fenachrone vessels were destroyed—after employing all the resources of his mind, now stored with the knowledge of rays accumulated by hundreds of generations of highly-trained research specialists in rays, he became convinced that it was an inherent impossibility to trace any ether wave with the velocity he desired.

"Can't be done, I guess, Mart," he confessed, ruefully. "You see, it works fine up to a certain point; but beyond that, nothing doing. I've just found out why—and in so doing, I think I've made a contribution to science. At velocities well below that of light, light-waves are shifted a minute amount, you know. At the velocity of light, and up to a velocity not even approached by the Fenachrone vessels on their longest trips, the distortion is still not serious—no matter how fast we want to travel in the Skylark, I think I can guarantee that we will still be able to see things. That is to be expected from the generally-accepted idea that the apparent velocity of any ether vibration is independent of the velocity of either source or receiver. However, that relationship fails at velocities far below that of fifth-order rays. At only a very small fraction of that speed the tracers I am following are so badly distorted that they disappear altogether, and I have to distort them backwards. That wouldn't be too bad, but when I get up to about one per cent of the velocity I want to use, I can't calculate a force that will operate to distort them back into recognizable wave-forms. That's another problem for Rovol to chew on, for another hundred years."

"That will, of course, slow up the work of clearing the Galaxy of the Fenachrone, but at the same time I see nothing about which to be alarmed," Crane replied. "You are working very much faster than you could have done by waiting for the torpedoes to arrive. The present condition is very satisfactory, I should say," and he waved his hand at the galactic model, in nearly three-fourths of whose volume the green lights had been replaced by pink ones.

"Yeah, pretty fair as far as that goes—we'll clean up in ten days or so—but I hate to be licked. Well, I might as well quit sobbing and get busy!"

In due time the nine hundred and sixth Fenachrone vessel was checked off on the model, and the two Terrestrials went in search of Drasnik, whom they found in his study, summing up and analyzing a mass of data, facts, and ideas which were being projected in the air around him.

"Well, our first job's done," Seaton stated. "What do you know that you feel like passing around?"

"My investigation is practically complete," replied the First of Psychology, gravely. "I have explored many Fenachrone minds, and without exception I have found them chambers of horror of a kind unimaginable to one of us. However, you are not interested in their psychology, but in facts bearing upon your problem. While such facts were scarce, I did discover a few interesting items. I spied upon them in public and in their most private haunts. I analyzed them individually and collectively, and from the few known facts and from the great deal of guesswork and conjecture there available to me, I have formulated a theory. I shall first give you the known facts. Their scientists cannot direct nor control any ray not propagated through ether, but they can detect one such frequency or band of frequencies which they call 'infra-rays' and which are probably the fifth-order rays, since they lie in the first level below the ether. The detector proper is a type of lamp, which gives a blue light at the ordinary intensity of such rays as would come from space or from an ordinary power plant, but gives a red light under strong excitation."

"Uh-huh, I get that O. K.," said Seaton. "Rovol's great-great-great-grandfather had 'em—I know all about 'em," Seaton encouraged Drasnik, who had paused, with a questioning glance. "I know exactly how and why such a detector works. We gave 'em an alarm, all right. Even though we were working on a tight beam from here to there, our secondary projector there was radiating enough to affect every such detector within a thousand miles."

Drasnik continued: "Another significant fact is that a great many persons—I learned of some five hundred, and there were probably many more—have disappeared without explanation and without leaving a trace; and it seems that they disappeared very shortly after our communication was delivered. One of these was Fenor, the Emperor. His family remain, however, and his son is not only ruling in his stead, but is carrying out his father's policies. The other disappearances are all alike and are peculiar in certain respects. First, every man who vanished belonged to the Party of Postponement—the minority party of the Fenachrone, who believe that the time for the Conquest has not yet come. Second, every one of them was a leader in thought in some field of usefulness, and every such field is represented by at least one disappearance—even the army, as General Fenimol, the Commander-in-Chief, and his whole family, are among the absentees. Third, and most remarkable, each such disappearance included an entire family, clear down to children and grand-children, however young. Another fact is that the Fenachrone Department of Navigation keeps a very close check upon all vessels, particularly vessels capable of navigating outer space. Every vessel built must be registered, and its location is always known from its individual tracer ray. No Fenachrone vessel is missing."

"I also sifted a mass of gossip and conjecture, some of which may bear upon the subject. One belief is that all the persons were put to death by Fenor's secret service, and that the Emperor was assassinated in revenge. The most widespread belief, however, is that they have fled. Some hold that they are in hiding in some remote shelter in the jungle, arguing that the rigid registration of all vessels renders a journey of any great length impossible and that the detector screens would have given warning of any vessel leaving the planet. Others think that persons as powerful as Fenimol and Ravindau could have built any vessel they chose with neither the knowledge nor consent of the Department of Navigation, or that they could have stolen a Navy vessel, destroying its records; and that Ravindau certainly could have so neutralized the screens that they would have given no alarm. These believe that the absent ones have migrated to some other solar system or to some other planet of the same sun. One old general loudly gave it as his opinion that the cowardly traitors had probably fled clear out of the Galaxy, and that it would be a good thing to send the rest of the Party of Postponement after them. There, in brief, are the salient points of my investigation in so far as it concerns your immediate problem."

"A good many straws pointing this way and that," commented Seaton. "However, we know that the 'postponers' are just as rabid on the idea of conquering the Universe as the others are—only they are a lot more cautious and won't take even a gambler's chance of a defeat. But you've formed a theory—what is it, Drasnik?"

"From my analysis of these facts and conjectures, in conjunction with certain purely psychological indices which we need not take time to go into now, I am certain that they have left their solar system, probably in an immense vessel built a long time ago and held in readiness for just such an emergency. I am not certain of their destination, but it is my opinion that they have left this Galaxy, and are planning upon starting anew upon some suitable planet in some other Galaxy, from which, at some future date, the Conquest of the Universe shall proceed as it was originally planned."

"Great balls of fire!" blurted Seaton. "They couldn't—not in a million years!" He thought a moment, then continued more slowly: "But they could—and, with their dispositions, they probably would. You're one hundred per cent. right, Drasnik. We've got a real job of hunting on our hands now. So-long, and thanks a lot."

Back in the projector Seaton prowled about in brown abstraction, his villainous pipe poisoning the circumambient air, while Crane sat, quiet and self-possessed as always, waiting for the nimble brain of his friend to find a way over, around, or through the obstacle confronting them.

"Got it, Mart!" Seaton yelled, darting to the board and setting up one integral after another. "If they did leave the planet in a ship, we'll be able to watch them go—and we'll see what they did, anyway, no matter what it was!"

"How? They've been gone almost a month already," protested Crane.

"We know within half an hour the exact time of their departure. We'll simply go out the distance light has traveled since that time, gather in the rays given off, amplify them a few billion times, and take a look at whatever went on."

"But we have no idea of what region of the planet to study, or whether it was night or day at the point of departure when they left."

"We'll get the council room, and trace events from there. Day or night makes no difference—we'll have to use infra-red anyway, because of the fog, and that's almost as good at night as in the daytime. There is no such thing as absolute darkness upon any planet, anyway, and we've got power enough to make anything visible that happened there, night or day. Mart, I've got power enough here to see and to photograph the actual construction of the pyramids of Egypt in that same way—and they were built thousands of years ago!"

"Heavens, what astounding possibilities!" breathed Crane. "Why, you could...."

"Yeah, I could do a lot of things," Seaton interrupted him rudely, "but right now we've got other fish to fry. I've just got the city we visited, at about the time we were there. General Fenimol, who disappeared, must be in the council room down here right now. I'll retard our projection, so that time will apparently pass more quickly, and we'll duck down there and see what actually did happen. I can heterodyne, combine, and recombine just as though we were watching the actual scene—it's more complicated, of course, since I have to follow it and amplify it too, but it works out all right."

"This is unbelievable, Dick. Think of actually seeing something that really happened in the past!"

"Yeah, it's kinda strong, all right. As Dot would say, it's just too perfectly darn outrageous. But we're doing it, ain't we? I know just how, and why. When we get some time I'll shoot the method into your brain. Well, here we are!"

Peering into the visiplates, the two men were poised above the immense central cone of the capital city of the Fenachrone. Viewing with infra-red light as they were, the fog presented no obstacle and the indescribable beauty of the city of concentric rings and the wonderfully luxuriant jungle growth were clearly visible. They plunged down into the council chamber, and saw Fenor, Ravindau, and Fenimol deep in conversation.

"With all the other feats of skill and sorcery you have accomplished, why don't you reconstruct their speech, also?" asked Crane, with a challenging glance.

"Well, old Doubting Thomas, it might not be absolutely impossible, at that. It would mean two projectors, however, due to the difference in speed of sound-waves and light-waves. Theoretically, sound-waves also extend to an infinite distance, but I don't believe that any possible detector and amplifier could reconstruct a voice more than an hour or so after it had spoken. It might, though—we'll have to try it some time, and see. You're fairly good at lip-reading, as I remember it. Get as much of it as you can, will you?"

As though they were watching the scene itself as it happened—which, in a sense, they were—they saw everything that had occurred. They saw Fenor die, saw the general's family board the airboat, saw the orderly embarkation of Ravindau's organization. Finally they saw the stupendous take-off of the first inter-galactic cruiser, and with that take-off, Seaton went into action. Faster and faster he drove that fifth-order beam along the track of the fugitive, until a speed was attained beyond which his detecting converters could not hold the ether-rays they were following. For many minutes Seaton stared intently into the visiplate, plotting lines and calculating forces, then he swung around to Crane.

"Well, Mart, noble old bean, solving the disappearances was easier than I thought it would be; but the situation as regards wiping out the last of the Fenachrone is getting no better, fast."

"I glean from the instruments that they are heading straight out into space away from the Galaxy, and I assume that they are using their utmost acceleration?"

"I'll say they're traveling! They're out in absolute space, you know, with nothing in the way and with no intention of reversing their power or slowing down—they must've had absolute top acceleration on every minute since they left. Anyway, they're so far out already that I couldn't hold even a detector on them, let alone a force that I can control. Well, let's snap into it, fellow—on our way!"

"Just a minute, Dick. Take it easy, what are your plans?"

"Plans! Why worry about plans? Blow up that planet before any more of 'em get away, and then chase that boat clear to Andromeda, if necessary. Let's go!"

"Calm down and be reasonable—you are getting hysterical again. They have a maximum acceleration of five times the velocity of light. So have we, exactly, since we adopted their own drive. Now if our acceleration is the same as theirs, and they have a month's start, how long will it take us to catch them?"

"Right again. Mart—I sure was going off half-cocked again," Seaton conceded ruefully, after a moment's thought. "They'd always be going a million or so times as fast as we would be, and getting further ahead of us in geometrical ratio. What's your idea?"

"I agree with you that the time has come to destroy the planet of Fenachrone. As for pursuing that vessel through intergalactic space, that is your problem. You must figure out some method of increasing our acceleration. Highly efficient as is this system of propulsion, it seems to me that the knowledge of the Norlaminians should be able to improve it in some detail. Even a slight increase in acceleration would enable us to overtake them eventually."

"Hm—m—m." Seaton, no longer impetuous, was thinking deeply. "How far are we apt to have to go?"

"Until we get close enough to them to use your rays—say half a million light-years."

"But surely they'll stop, some time?"

"Of course, but not necessarily for many years. They are powered and provisioned for a hundred years, you remember, and are going to 'a distant galaxy.' Such a one as Ravindau would not have specified a distant Galaxy idly, and the very closest Galaxies are so far away that even the Fenachrone astronomers, with their reflecting mirrors five miles in diameter, could form only the very roughest approximations of the true distances."

"Our astronomers are all wet in their guesses, then?"

"Their estimates are, without exception, far below the true values. They are not even of the correct order of magnitude.'"

"Well, then, let's mop up on that planet. Then we'll go places and do things."

Seaton had already located the magazines in which the power bars of the Fenachrone war-vessels were stored, and it was a short task to erect a secondary projector of force in the Fenachrone atmosphere. Working out of that projector, beams of force seized one of the immense cylinders of plated copper and at Seaton's direction transported it rapidly to one of the poles of the planet, where electrodes of force were clamped upon it. In a similar fashion seventeen more of the frightful bombs were placed, equidistant over the surface of the world of the Fenachrone, so that when they were simultaneously exploded, the downward forces would be certain to meet sufficient resistance to assure complete demolition of the entire globe. Everything in readiness, Seaton's hand went to the plunger switch and closed upon it. Then, his face white and wet, he dropped his hand.

"No use, Mart—I can't do it. It pulls my cork. I know darn well you can't either—I'll yell for help."

"Have you got it on the infra-red?" asked Dunark calmly, as he shot up into the projector in reply to Seaton's call. "I want to see this, all of it."

"It's on—you're welcome to it," and, as the Terrestrials turned away, the whole projector base was illuminated by a flare of intense, though subdued light. For several minutes Dunark stared into the visiplate, savage satisfaction in every line of his fierce green face as he surveyed the havoc wrought by those eighteen enormous charges of incredible explosive.

"A nice job of clean-up, Dick," the Osnomian prince reported, turning away from the visiplate. "It made a sun of it—the original sun is now quite a splendid double star. Everything was volatized, clear out, far beyond their outermost screen."

"It had to be done, of course—it was either them or else all the rest of the Universe," Season said, jerkily. "However, even that fact doesn't make it go down easy. Well, we're done with this projector. From now on it's strictly up to us and Skylark Three. Let's beat it over there and see if they've got her done yet—they were due to finish up today, you know."

It was a silent group who embarked in the little airboat. Half way to their destination, however, Seaton came out of his blue mood with a yell.

"Mart, I've got it! We can give the Lark a lot more acceleration than they are getting—and won't need the assistance of all the minds of Norlamin, either."

"How?"

"By using one of the very heavy metals for fuel. The intensity of the power liberated is a function of atomic weight, or atomic number, and density; but the fact of liberation depends upon atomic configuration—a fact which you and I figured out long ago. However, our figuring didn't go far enough—it couldn't: we didn't know anything then. Copper happens to be the most efficient of the few metals which can be decomposed at all under ordinary excitation—that is, by using an ordinary coil, such as we and the Fenachrone both use. But by using special exciters, sending out all the orders of rays necessary to initiate the disruptive processes, we can use any metal we want to. Osnome has unlimited quantities of the heaviest metals, including radium and uranium. Of course we can't use radium and live—but we can and will use uranium, and that will give us something like four times the acceleration possible with copper. Dunark, what say you snap over there and smelt us a cubic mile of uranium? No—hold it—I'll put a flock of forces on the job. They'll do it quicker, and I'll make 'em deliver the goods. They'll deliver 'em fast, too, believe us—we'll see to that with a ten-ton bar. The uranium bars'll be ready to load tomorrow, and we'll have enough power to chase those birds all the rest of our lives!"

Returning to the projector, Seaton actuated the complex system of forces required for the smelting and transportation of the enormous amount of metal necessary, and as the three men again boarded their aerial conveyance, the power-bar in the projector behind them flared into violet incandescence under the load already put upon it by the new uranium mine in distant Osnome.

The Skylark lay stretched out over two miles of country, exactly as they had last seen her, but now, instead of being water-white, the ten-thousand-foot cruiser of the void was one jointless, seamless structure of sparkling, transparent, purple inoson. Entering one of the open doors, they stepped into an elevator and were whisked upward into the control room, in which a dozen of the aged, white-bearded students of Norlamin were grouped about a banked and tiered mass of keyboards, which Seaton knew must be the operating mechanism of the extraordinarily complete fifth-order projector he had been promised.

"Ah, youngsters, you are just in time. Everything is complete and we are just about to begin loading."

"Sorry, Rovol, but we'll have to make a couple of changes—have to rebuild the exciter or build another one," and Seaton rapidly related what they had learned, and what they had decided to do.

"Of course, uranium is a much more efficient source of power," agreed Rovol, "and you are to be congratulated for thinking of it. It perhaps would not have occurred to one of us, since the heavy metals of that highly efficient group are very rare here. Building a new exciter for uranium is a simple task, and the converters for the corona-loss will, of course, require no change, since their action depends only upon the frequency of the emitted losses, not upon their magnitude."

"Hadn't you suspected that some of the Fenachrone might be going to lead us a life-long chase?" asked Dunark curiously.

"We have not given the matter a thought, my son," the Chief of the Five made answer. "As your years increase, you will learn not to anticipate trouble and worry. Had we thought and worried over the matter before the time had arrived, you will note that it would have been pain wasted, for our young friend Seaton has avoided that difficulty in a truly scholarly fashion."

"All set, then, Rovol?" asked Seaton, when the forces flying from the projector had built the compound exciter which would make possible the disruption of the atoms of uranium. "The metal, enough of it to fill all the spare space in the hull, will be here tomorrow. You might give Crane and me the method of operating this projector, which I see is vastly more complex even than the one in the Area of Experiment."

"It is the most complete thing ever seen upon Norlamin," replied Rovol with a smile. "Each of us installed everything in it that he could conceive of ever being of the slightest use, and since our combined knowledge covers a large field, the projector is accordingly quite comprehensive."

Multiple headsets were donned, and from each of the Norlaminian brains there poured into the minds of the two Terrestrials a complete and minute knowledge of every possible application of the stupendous force-control banked in all its massed intricacy before them.

"Well, that's some outfit!" exulted Seaton in pleased astonishment as the instructions were concluded. "It can do anything but lay an egg—and I'm not a darn bit sure that we couldn't make it do that! Well, let's call the girls and show them around this thing that's going to be their home for quite a while."

While they were waiting, Dunark led Seaton aside.

"Dick, will you need me on this trip?" he asked. "Of course I knew there was something on your mind when you didn't send me home when you let Urvan, Carfon and the others go back."

"No, we're going it alone—unless you want to come along. I did want you to stick around until I got to a good chance to talk to you alone—now will be a good a time as any. You and I have traded brains, and besides, we've been through quite a lot of grief together, here and there—I want to apologize to you for not passing along to you all this stuff I've been getting here. In fact, I really wish I didn't have to have it myself. Get me?"

"Got you? I'm 'way ahead of you! Don't want it, not any part of it—that's why I've stayed away from any chance of learning any of it, and the one reason why I am going back home instead of going with you. I have just brains enough to realize that neither I nor any other man of my race should have it. By the time we grow up to it naturally we shall be able to handle it, but not until then."

The two brain brothers grasped hands strongly, and Dunark continued in a lighter vein: "It takes all kinds of people to make a world, you know—and all kinds of races, except the Fenachrone, to make a Universe. With Mardonale gone, the evolution of Osnome shall progress rapidly, and while we may not reach the Ultimate Goal, I have learned enough from you already to speed up our progress considerably."

"Well, that's that. Had to get it off my chest, although I knew you'd get the idea all right. Here are the girls—Sitar too. We'll show 'em around."

Seaton's first thought was for the very brain of the ship—the precious lens of neutronium in its thin envelope of the eternal jewel—without which the beam of fifth-order rays could not be directed. He found it a quarter of a mile back from the needle-sharp prow, exactly in the longitudinal axis of the hull, protected from any possible damage by bulkhead after massive bulkhead of impregnable inoson. Satisfied upon that point, he went in search of the others, who were exploring their vast new space-ship.

Huge as she was, there was no waste space—her design was as compact as that of a fine radio set. The living quarters were grouped closely about the central compartment, which housed the power plants, the many ray generators and projectors, and the myriads of controls of the marvelous mechanism for the projection and direction of fifth-order rays. Several large compartments were devoted to the machinery which automatically serviced the vessel—refrigerators, heaters, generators and purifiers for water and air, and the numberless other mechanisms which would make the cruiser a comfortable and secure home, as well as an invincible battleship, in the heatless, lightless, airless, matterless waste of illimitable, inter-galactic space. Many compartments were for the storage of food-supplies, and these were even then being filled by forces under the able direction of the first of Chemistry.

"All the comforts of home, even to the labels," Seaton grinned, as he read "Dole No. 1" upon cans of pineapple which had never been within thousands of light-years of the Hawaiian Islands, and saw quarter after quarter of fresh meat going into the freezer room from a planet upon which no animal other than man had existed for many thousands of years. Nearly all of the remaining millions of cubic feet of space were for the storage of uranium for power, a few rooms already having been filled with ingot inoson for repairs. Between the many bulkheads that divided the ship into numberless airtight sections, and between the many concentric skins of purple metal that rendered the vessel space-worthy and sound, even though slabs many feet thick were to be shown off in any direction—in every nook and cranny could be stored the metal to keep those voracious generators full-fed, no matter how long or how severe the demand for power. Every room was connected through a series of tubular tunnels, along which force-propelled cars or elevators slid smoothly—tubes whose walls fell together into air-tight seals at any point, in case of a rupture.

As they made their way back to the great control-room room of the vessel, they saw something that because of its small size and clear transparency they had not previously seen. Below that room, not too near the outer skin, in a specially-built spherical launching space, there was Skylark Two, completely equipped and ready for an interstellar journey on her own account!

"Why, hello, little stranger!" Margaret called. "Rovol, that was a kind thought on your part. Home wouldn't quite be home without our old Skylark, would it, Martin?"

"A practical thought, as well as a kind one," Crane responded. "We undoubtedly will have occasion to visit places altogether too small for the really enormous bulk of this vessel."

"Yes, and whoever heard of a sea-going ship without a small boat?" put in irrepressible Dorothy. "She's just too perfectly kippy for words, sitting up there, isn't she?"