Martin Crane reclined in a massive chair, the fingers of his right hand lightly touching those of his left, listening attentively. Richard Seaton strode up and down the room before his friend, his unruly brown hair on end, speaking savagely between teeth clenched upon the stem of his reeking, battered briar, brandishing a sheaf of papers.

"Mart, we're stuck—stopped dead. If my head wasn't made of solid blue mush I'd have had a way figured out of this thing before now, but I can't. With that zone of force the Skylark would have everything imaginable—without it, we're exactly where we were before. That zone is immense, man—terrific—its possibilities are unthinkable—and I'm so cussed dumb that I can't find out how to use it intelligently—can't use it at all, for that matter. By its very nature it is impenetrable to any form of matter, however applied; and this calc here," slapping viciously the sheaf of papers containing his calculations, "shows that it must also be opaque to any wave whatever, propagated through air or through ether, clear down to cosmic rays. Behind it, we would be blind and helpless, so we can't use it at all. It drives me frantic! Think of a barrier of pure force, impalpable, immaterial, and exerted along a geometrical surface of no thickness whatever—and yet actual enough to stop even a Millikan ray that travels a hundred thousand light-years and then goes through twenty-seven feet of solid lead just like it was so much vacuum! That's what we're up against! However, I'm going to try out that model, Mart, right now. Come on, guy, snap into it! Let's get busy!"

"You are getting idiotic again, Dick," Crane rejoined calmly, without moving. "You know, even better than I do, that you are playing with the most concentrated essence of energy that the world has ever seen. That zone of force probably can be generated——"

"Probably, nothing!" barked Seaton. "It's just as evident a fact as that stool," kicking the unoffending bit of furniture half-way across the room as he spoke. "If you'd've let me, I'd've shown it to you yesterday!"

"Undoubtedly, then. Grant that it is impenetrable to all matter and to all known waves. Suppose that it should prove impenetrable also to gravitation and to magnetism? Those phenomena probably depend upon the ether, but we know nothing fundamental of their nature, nor of that of the ether. Therefore your calculations, comprehensive though they are, cannot predict the effect upon them of your zone of force. Suppose that that zone actually does set up a barrier in the ether, so that it nullifies gravitation, magnetism, and all allied phenomena; so that the power-bars, the attractors and repellers, cannot work through it? Then what? As well as showing me the zone of force, you might well have shown me yourself flying off into space, unable to use your power and helpless if you released the zone. No, we must know more of the fundamentals before you try even a small-scale experiment."

"Oh, bugs! You're carrying caution to extremes, Mart. What can happen? Even if gravitation should be nullified, I would rise only slowly, heading south the angle of our latitude—that's thirty-nine degrees—away from the perpendicular. I couldn't shoot off on a tangent, as some of these hot-heads have been claiming. Inertia would make me keep pace, approximately, with the earth in its rotation. I would rise slowly—only as fast as the tangent departs from the curvature of the earth's surface. I haven't figured out how fast that is, but it must be pretty slow."

"Pretty slow?" Crane smiled. "Figure it out."

"All right—but I'll bet it's slower than the rise of a toy balloon." Seaton threw down the papers and picked up his slide-rule, a twenty-inch trigonometrical duplex. "You'll concede that it is allowable to neglect the radial component of the orbital velocity of the earth for a first approximation, won't you—or shall I figure that in too?"

"You may ignore that factor."

"All right—let's see. Radius of rotation here in Washington would be cosine latitude times equatorial radius, approximately—call it thirty-two hundred miles. Angular velocity, fifteen degrees an hour. I want secant fifteen less one times thirty-two hundred. Right? Secant equals one over cosine—um-m-m-m—one point oh three five. Then point oh three five times thirty-two hundred. Hundred and twelve miles first hour. Velocity constant with respect to sun, accelerated respecting point of departure. Ouch! You win, Mart—I'd kinda step out! Well, how about this, then? I'll put on a vacuum suit and carry rations. Harness outside, with the same equipment I used in the test flights before we built Skylark I—plus the new stuff and a coil. Then throw on the zone, and see what happens. There can't be any jar in taking off, and with that outfit I can get back O. K. if I go clear to Jupiter!"

Crane sat in silence, his keen mind considering every aspect of the motions possible, of velocity, of acceleration, of inertia. He already knew well Seaton's resourcefulness in crises and his physical and mental strength.

"As far as I can see, that might be safe," he admitted finally, "and we really should know something about it besides the theory."

"Fine, Mart—let's get busy! I'll be ready in five minutes. Yell for the girls, will you? They'd break us off at the ankles if we pull anything new without letting them in on it."

A few minutes later the "girls" strolled out into Crane Field, arms around each other—Dorothy Seaton, her gorgeous auburn hair framing violet eyes and vivid coloring; black-haired, dark-eyed Margaret Crane.

"Br-r-r, it's cold!" Dorothy shivered, wrapping her coat more closely about her. "This must be the coldest day Washington has seen for years!"

"It is cold," Margaret agreed. "I wonder what they are going to do out here, this kind of weather?"

As she spoke, the two men stepped out of the "testing shed"—the huge structure that housed their Osnomian-built space-cruiser, "Skylark II." Seaton waddled clumsily, wearing as he did a Crane vacuum-suit which, built of fur, canvas, metal and transparent silica, braced by steel netting and equipped with air-tanks and heaters, rendered its wearer independent of outside conditions of temperature and pressure. Outside this suit he wore a heavy harness of leather, buckled about his body, shoulders, and legs, attached to which were numerous knobs, switches, dials, bakelite cases, and other pieces of apparatus. Carried by a strong aluminum framework in turn supported by the harness, the universal bearing of a small power-bar rose directly above his grotesque-looking helmet.

"What do you think you're going to do in that thing, Dickie?" Dorothy called. Then, knowing that he could not hear her voice, she turned to Crane. "What are you letting that precious husband of mine do now, Martin? He looks as though he were up to something."

While she was speaking, Seaton had snapped the release of his face plate.

"Nothing much, Dottie. Just going to show you-all the zone of force. Mart wouldn't let me turn it on, unless I got all cocked and primed for a year's journey into space."

"Dot, what is that zone of force, anyway?" asked Margaret.

"Oh, it's something Dick got into his head during that awful fight they had on Osnome. He hasn't thought of anything else since we got back. You know how the attractors and repellers work? Well, he found out something funny about the way everything acted while the Mardonalians were bombarding them with a certain kind of a wave-length. He finally figured out the exact ray that did it, and found out that if it is made strongly enough, it acts as if a repeller and attractor were working together—only so much stronger that nothing can get through the boundary, either way—in fact, it's so strong that it cuts anything in two that's in the way. And the funny thing is that there's nothing there at all, really; but Dick says that the forces meeting there, or something, make it act as though something really important were there. See?"

"Uh-huh," assented Margaret, doubtfully, just as Crane finished the final adjustments and moved toward them. A safe distance away from Seaton, he turned and waved his hand.

Instantly Seaton disappeared from view, and around the place where he had stood there appeared a shimmering globe some twenty feet in diameter—a globe apparently a perfect spherical mirror, which darted upward and toward the south. After a moment the globe disappeared and Seaton was again seen. He was now standing upon a hemispherical mass of earth. He darted back toward the group upon the ground, while the mass of earth fell with a crash a quarter of a mile away. High above their heads the mirror again encompassed Seaton, and again shot upward and southward. Five times this maneuver was repeated before Seaton came down, landing easily in front of them and opening his helmet.

"It's just what we thought it was, only worse," he reported tersely. "Can't do a thing with it. Gravitation won't work through it—bars won't—nothing will. And dark? Dark! Folks, you ain't never seen no darkness, nor heard no silence. It scared me stiff!"

"Poor little boy—afraid of the dark!" exclaimed Dorothy. "We saw absolute blackness in space."

"Not like this, you didn't. I just saw absolute darkness and heard absolute silence for the first time in my life. I never imagined anything like it—come on up with me and I'll show it to you."

"No you won't!" his wife shrieked as she retreated toward Crane. "Some other time, perhaps."

Seaton removed the harness and glanced at the spot from which he had taken off, where now appeared a hemispherical hole in the ground.

"Let's see what kind of tracks I left, Mart," and the two men bent over the depression. They saw with astonishment that the cut surface was perfectly smooth, with not even the slightest roughness or irregularity visible. Even the smallest loose grains of sand had been sheared in two along a mathematically exact hemispherical surface by the inconceivable force of the disintegrating copper bar.

"Well, that sure wins the——"

An alarm bell sounded. Without a glance around, Seaton seized Dorothy and leaped into the testing shed. Dropping her unceremoniously to the floor he stared through the telescope sight of an enormous ray-generator which had automatically aligned itself upon the distant point of liberation of intra-atomic energy which had caused the alarm to sound. One hand upon the switch, his face was hard and merciless as he waited to make sure of the identity of the approaching space-ship, before he released the frightful power of his generator upon it.

"I've been expecting DuQuesne to try it again," he gritted, striving to make out the visitor, yet more than two hundred miles distant. "He's out to get you, Dot—and this time I'm not just going to warm him up and scare him away, as I did last time. This time that misguided mutt's going to get frizzled right.... I can't locate him with this small telescope, Mart. Line him up in the big one and give me the word, will you?"

"I see him, Dick, but it is not DuQuesne's ship. It is built of transparent arenak, like the 'Kondal.' Even though it seems impossible, I believe it is the 'Kondal'."

"Maybe so, and again maybe DuQuesne built it—or stole it. On second thought, though, I don't believe that DuQuesne would be fool enough to tackle us again in the same way—but I'm taking no chances.... O. K., it is the 'Kondal,' I can see Dunark and Sitar myself, now."

The transparent vessel soon neared the field and the four Terrestrials walked out to greet their Osnomian friends. Through the arenak walls they recognized Dunark, Kofedix of Kondal, at the controls, and saw Sitar, his beautiful young queen, lying in one of the seats near the wall. She attempted a friendly greeting, but her face was strained as though she were laboring under a burden too great for her to bear.

As they watched, Dunark slipped a helmet over his head and one over Sitar's, pressed a button to open one of the doors, and supported her toward the opening.

"They mustn't come out, Dick!" exclaimed Dorothy in dismay. "They'll freeze to death in five minutes without any clothes on!"

"Yes, and Sitar can't stand up under our gravitation, either—I doubt if Dunark can, for long," and Seaton dashed toward the vessel, motioning the visitor back.

But misunderstanding the signal, Dunark came on. As he clambered heavily through the door he staggered as though under an enormous weight, and Sitar collapsed upon the frozen ground. Trying to help her, half-kneeling over her, Dunark struggled, his green skin paling to a yellowish tinge at the touch of the bitter and unexpected cold. Seaton leaped forward and gathered Sitar up in his mighty arms as though she were a child.

"Help Dunark back in, Mart," he directed crisply. "Hop in, girls—we've got to take these folks back up where they can live."

Seaton shut the door, and as everyone lay flat in the seats Crane, who had taken the controls, applied one notch of power and the huge vessel leaped upward. Miles of altitude were gained before Crane brought the cruiser to a stop and locked her in place with an anchoring attractor.

"There," he remarked calmly, "gravitation here is approximately the same as it is upon Osnome."

"Yes," put in Seaton, standing up and shedding clothing in all directions, "and I rise to remark that we'd better undress as far as the law allows—perhaps farther. I never did like Osnomian ideas of comfortable warmth, but we can endure it by peeling down to bedrock——"

Sitar jumped up happily, completely restored, and the three women threw their arms around each other.

"What a horrible, terrible, frightful world!" exclaimed Sitar, her eyes widening as she thought of her first experience with our earth. "Much as I love you, I shall never dare try to visit you again. I have never been able to understand why you Terrestrials wear what you call 'clothes,' nor why you are so terribly, brutally strong. Now I really know—I will feel the utterly cold and savage embrace of that awful earth of yours as long as I live!"

"Oh, it's not so bad, Sitar." Seaton, who was shaking both of Dunark's hands vigorously, assured her over his shoulder. "All depends on where you were raised. We like it that way, and Osnome gives us the pip. But you poor fish," turning again to Dunark, "with all my brains inside your skull, you should have known what you were letting yourself in for."

"That's true, after a fashion," Dunark admitted, "but your brain told me that Washington was hot. If I'd have thought to recalculate your actual Fahrenheit degrees into our loro ... but that figures only forty-seven and, while very cold, we could have endured it—wait a minute, I'm getting it. You have what you call 'seasons.' This, then, must be your 'winter.' Right?"

"Right the first time. That's the way your brain works behind my pan, too. I could figure anything out all right after it happened, but hardly ever beforehand—so I guess I can't blame you much, at that. But what I want to know is, how'd you get here? It would take more than my brains—you can't see our sun from anywhere near Osnome, even if you knew exactly where to look for it."

"Easy. Remember those wrecked instruments you threw out of Skylark I when we built Skylark II?" Having every minute detail of the configuration of Seaton's brain engraved upon his own, Dunark spoke English in Seaton's own characteristic careless fashion. Only when thinking deeply or discussing abstruse matter did Seaton employ the carefully selected and precise phrasing, which he knew so well how to use. "Well, none of them was beyond repair and the juice was still on most of them. One was an object-compass bearing on the Earth. We simply fixed the bearings, put on some minor improvements, and here we are."

"Let us all sit down and be comfortable," he continued, changing into the Kondalian tongue without a break, "and I will explain why we have come. We are in most desperate need of two things which you alone can supply—salt, and that strange metal, 'X'. Salt I know you have in great abundance, but I know that you have very little of the metal. You have only the one compass upon that planet?"

"That's all—one is all we set on it. However, we've got close to half a ton of the metal on hand—you can have all you want."

"Even if I took it all, which I would not like to do, that would be less than half enough. We must have at least one of your tons, and two tons would be better."

"Two tons! Holy cat! Are you going to plate a fleet of battle cruisers?"

"More than that. We must plate an area of copper of some ten thousand square miles—in fact, the very life of our entire race depends upon it."

"It's this way," he continued, as the four earth-beings stared at him in wonder. "Shortly after you left Osnome we were invaded by the inhabitants of the third planet of our fourteenth sun. Luckily for us they landed upon Mardonale, and in less than two days there was not a single Osnomian left alive upon that half of the planet. They wiped out our grand fleet in one brief engagement, and it was only the Kondal and a few more like her that enabled us to keep them from crossing the ocean. Even with our full force of these vessels, we cannot defeat them. Our regular Kondalian weapons were useless. We shot explosive copper charges against them of such size as to cause earthquakes all over Osnome, without seriously crippling their defenses. Their offensive weapons are almost irresistible—they have generators that burn arenak as though it were so much paper, and a series of deadly frequencies against which only a copper-driven ray screen is effective, and even that does not stand up long."

"How come you lasted till now, then?" asked Seaton.

"They have nothing like the Skylark, and no knowledge of intra-atomic energy. Therefore their space-ships are of the rocket type, and for that reason they can cross only at the exact time of conjunction, or whatever you call it—no, not conjunction, exactly, either, since the two planets do not revolve around the same sun: but when they are closest together. Our solar system is so complex, you know, that unless the trips are timed exactly, to the hour, the vessels will not be able to land upon Osnome, but will be drawn aside and be lost, if not actually drawn into the vast central sun. Although it may not have occurred to you, a little reflection will show that the inhabitants of all the central planets, such as Osnome, must perforce be absolutely ignorant of astronomy, and of all the wonders of outer space. Before your coming we knew nothing beyond our own solar system, and very little of that. We knew of the existence of only such of the closest planets as were brilliant enough to be seen in our continuous sunlight, and they were few. Immediately after your coming I gave your knowledge of astronomy to a group of our foremost physicists and mathematicians, and they have been working ceaselessly from space-ships—close enough so that observations could be recalculated to Osnome, and yet far enough away to afford perfect 'seeing,' as you call it."

"But I don't know any more about astronomy than a pig does about Sunday," protested Seaton.

"Your knowledge of details is, of course, incomplete," conceded Dunark, "but the detailed knowledge of the best of your Earthly astronomers would not help us a great deal, since we are so far removed from you in space. You, however, have a very clear and solid knowledge of the fundamentals of the science, and that is what we need, above all things."

"Well, maybe you're right, at that. I do know the general theory of the motions, and I studied some Celestial Mechanics. I'm awfully weak on advanced theory, though, as you'll find out when you get that far."

"Perhaps—but since our enemies have no knowledge of astronomy whatever, it is not surprising that their rocket-ships can be launched only at one particularly favorable time; for there are many planets and satellites, of which they can know nothing, to throw their vessels off the course.

"Some material essential to the operation of their war machinery apparently must come from their own planet, for they have ceased attacking, have dug in, and are simply holding their ground. It may be that they had not anticipated as much resistance as we could offer with space-ships and intra-atomic energy. At any rate, they have apparently saved enough of that material to enable them to hold out until the next conjunction—I cannot think of a better word for it—shall occur. Our forces are attacking constantly, with all the armament at our command, but it is certain that if the next conjunction is allowed to occur, it means the end of the entire Kondalian nation."'

"What d'you mean 'if the next conjunction is allowed to occur?'" interjected Seaton. "Nobody can stop it."

"I am stopping it," Dunark stated quietly, grim purpose in every lineament. "That conjunction shall never occur. That is why I must have the vast quantities of salt and 'X'. We are building abutments of arenak upon the first satellite of our seventh planet, and upon our sixth planet itself. We shall cover them with plated active copper, and install chronometers to throw the switches at precisely the right moment. We have calculated the exact times, places, and magnitudes of the forces to be used. We shall throw the sixth planet some distance out of its orbit, and force the first satellite of the seventh planet clear out of that planet's influence. The two bodies whose motions we have thus changed will collide in such a way that the resultant body will meet the planet of our enemies in head-on collision, long before the next conjunction. The two bodies will be of almost equal masses, and will have opposite and approximately equal velocities; hence the resultant fused or gaseous mass will be practically without velocity and will fall directly into the fourteenth sun."

"Wouldn't it be easier to destroy it with an explosive copper bomb?"

"Easier, yes, but much more dangerous to the rest of our solar system. We cannot calculate exactly the effect of the collisions we are planning—but it is almost certain that an explosion of sufficient violence to destroy all life upon the planet would disturb its motion sufficiently to endanger the entire system. The way we have in mind will simply allow the planet and one satellite to drop out quietly—the other planets of the same sun will soon adjust themselves to the new conditions, and the system at large will be practically unaffected—at least, so we believe."

Seaton's eyes narrowed as his thoughts turned to the quantities of copper and "X" required and to the engineering features of the project; Crane's first thought was of the mathematics involved in a computation of that magnitude and character; Dorothy's quick reaction was one of pure horror.

"He can't, Dick! He mustn't! It would be too ghastly! It's outrageous—it's unthinkable—it's—it's—it's simply too horrible!" Her violet eyes flamed, and Margaret joined in:

"That would be awful, Martin. Think of the destruction of a whole planet—of an entire world—with all its inhabitants! It makes me shudder, even to think of it."

Dunark leaped to his feet, ablaze. But before he could say a word, Seaton silenced him.

"Shut up, Dunark! Pipe down! Don't say anything you'll be sorry for—let me tell 'em! Close your mouth, I tell you!" as Dunark still tried to get a word in, "I tell you I'll tell 'em, and when I tell 'em they stay told! Now listen, you two girls—you're going off half-cocked and you're both full of little red ants. What do you think Dunark is up against? Sherman chirped it when he described war—and this is a real he-war; a brand totally unknown on our Earth. It isn't a question of whether or not to destroy a population—the only question is which population is to be destroyed. One of them's got to go. Remember those folks go into a war thoroughly, and there isn't a thought, even remotely resembling our conception of mercy in any of their minds on either side. If Dunark's plans go through the enemy nation will be wiped out. That is horrible, of course. But on the other hand, if we block him off from salt and 'X,' the entire Kondalian nation will be destroyed just as thoroughly and efficiently, and even more horribly—not one man, woman, or child would be spared. Which nation do you want saved? Play that over a couple of times on your adding machine, Dot, and let me know what you get."

Dorothy, taken aback, opened and closed her mouth twice before she found her voice.

"But, Dick, they couldn't possibly. Would they kill them all, Dick? Surely they wouldn't—they couldn't."

"Surely they would—and could. They do—it's good technique in those parts of the Galaxy. Dunark has just told us of how they killed every member of the entire race of Mardonalians, in forty hours. Kondal would go the same way. Don't kid yourself, Dimples—don't be a child. War up there is no species of pink tea, believe me—half of my brain has been through thirty years of Osnomian warfare, and I know precisely what I'm talking about. Let's take a vote. Personally, I'm in favor of Osnome. Mart?"

"Osnome."

"Dottie? Peggy?" Both remained silent for some time, then Dorothy turned to Margaret.

"You tell him, Peggy—we both feel the same way."

"Dick, you know that we wouldn't want the Kondalians destroyed—but the other is so—such a—well, such an utter shrecklichkeit—isn't there some other way out?"

"I'm afraid not—but if there is any other possible way out, I'll do my da—to help find it," he promised. "The ayes have it. Dunark, we'll skip over to that 'X' planet and load you up."

Dunark grasped Seaton's hand. "Thanks, Dick," he said, simply. "But before you help me farther, and lest I might be in some degree sailing under false colors, I must tell you that, wearer of the seven disks though you are, Overlord of Osnome though you are, my brain brother though you are; had you decided against me, nothing but my death could have kept me away from that salt and your 'X' compass."

"Why sure," assented Seaton, in surprise. "Why not? Fair enough! Anybody would do the same—don't let that bother you."

"How is your supply of platinum?" asked Dunark.

"Mighty low. We had about decided to hop over there after some. I want some of your textbooks on electricity and so on, too. I see you brought a load of platinum with you."

"Yes, a few hundred tons. We also brought along an assortment of books I knew you would be interested in, a box of radium, a few small bags of gems of various kinds, and some of our fabrics, Sitar thought your Karfediro would like to have. While we are here, I would like to get some books on chemistry and some other things."

"We'll get you the Congressional Library, if you want it, and anything else you think you'd like. Well, gang, let's go places and do things! What to do, Mart?"

"We had better drop back to Earth, have the laborers unload the platinum, and load on the salt, books, and other things. Then both ships will go to the 'X' planet, as we will each want compasses on it, for future use. While we are loading, I should like to begin remodeling our instruments; to make them something like these; with Dunark's permission. These instruments are wonders, Dick—vastly ahead of anything I have ever seen. Come and look at them, if you want to see something really beautiful."

"Coming up. But say, Mart, while I think of it, we mustn't forget to install a zone-of-force apparatus on this boat, too. Even though we can't use it intelligently, it certainly would be a winner as a defense. We couldn't hurt anybody through it, of course, but if we should happen to be getting licked anywhere, all we'd have to do would be to wrap ourselves up in it. They couldn't touch us. Nothing in the ether spectrum is corkscrewy enough to get through it."

"That's the second idea you've had since I've known you, Dicky," Dorothy smiled at Crane. "Do you think he should be allowed to run at large, Martin?"

"That is a real idea. We may need it—you never can tell. Even if we never find any other use for the zone of force, that one is amply sufficient to justify its installation."

"Yes, it would be, for you—and I'm getting to be a regular Safety-First Simon myself, since they opened up on us. What about those instruments?"

The three men gathered around the instrument-board and Dunark explained the changes he had made—and to such men as Seaton and Crane it was soon evident that they were examining an installation embodying sheer perfection of instrumental control—a system which only those wonder instrument-makers, the Osnomians, could have devised. The new object-compasses were housed in arenak cases after setting, and the housings were then exhausted to the highest attainable vacuum. Oscillation was set up by means of one carefully standardized electrical impulse, instead of by the clumsy finger-touch Seaton had used. The bearings, built of arenak and Osnomian jewels, were as strong as the axles of a truck and yet were almost perfectly frictionless.

"I like them myself," admitted Dunark. "Without a load the needles will rotate freely more than a thousand hours on the primary impulse, as against a few minutes in the old type; and under load they are many thousands of times as sensitive."

"You're a blinding flash and a deafening report, ace!" declared Seaton, enthusiastically. "That compass is as far ahead of my model as the Skylark is ahead of Wright's first glider."

The other instruments were no less noteworthy. Dunark had adopted the Perkins telephone system, but had improved it until it was scarcely recognized and had made it capable of almost unlimited range. Even the guns—heavy rapid-firers, mounted in spherical bearings in the walls—were aimed and fired by remote control, from the board. He had devised full automatic steering controls; and meters and recorders for acceleration, velocity, distance, and flight-angle. He had perfected a system of periscopic vision, which enabled the pilot to see the entire outside surfaces of the shell, and to look toward any point of the heavens without interference.

"This kind of takes my eye, too, prince," Seaton said, as he seated himself, swung a large, concave disk in front of him, and experimented with levers and dials. "You certainly can't call this thing a periscope—it's no more a periscope than I am a polyp. When you look through this plate, it's better than looking out of a window—it subtends more than the angle of vision, so that you can't see anything but out-of-doors—I thought for a second I was going to fall out. What do you call 'em, Dunark?"

"Kraloto. That would be in English ... Seeing-plate? Or rather, call it 'visiplate'."

"That's a good word. Mart, take a look if you want to see a set of perfect lenses and prisms."

Crane looked into the visiplate and gasped. The vessel had disappeared—he was looking directly down upon the Earth below him!

"No trace of chromatic, spherical, or astigmatic aberration," he reported in surprise. "The refracting system is invisible—it seems as though nothing intervenes between the eye and the object. You perfected all these things since we left Osnome, Dunark? You are in a class by yourself. I could not even copy them in less than a month, and I never could have invented them."

"I did not do it alone, by any means. The Society of Instrument-Makers, of which I am only one member, installed and tested more than a hundred systems. This one represents the best features of all the systems tried. It will not be necessary for you to copy them. I brought along two complete duplicate sets for the Skylark, as well as a dozen or so of the compasses. I thought that perhaps these particular improvements might not have occurred to you, since you Terrestrials are not as familiar as we are with complex instrumental work."

Crane and Seaton spoke together.

"That was thoughtful of you, Dunark, and we appreciated it fully."

"That puts four more palms on your Croix de Guerre, ace. Thanks a lot."

"Say, Dick," called Dorothy, from her seat near the wall. "If we're going down to the ground, how about Sitar?"

"By lying down and not doing anything, and by staying in the vessel, where it is warm, she will be all right for the short time we must stay here," Dunark answered for his wife. "I will help all I can, but I do not know how much that will be."

"It isn't so bad lying down." Sitar agreed. "I don't like your Earth a bit, but I can stand it a little while. Anyway, I must stand it, so why worry about it?"

"'At-a-girl!" cheered Seaton. "And as for you, Dunark, you'll pass the time just like Sitar does—lying down. If you do much chasing around down there where we live, you're apt to get your lights and liver twisted all out of shape—so you'll stay put, horizontal. We've got men enough around the shop to eat this cargo in three hours, let alone unload it. While they unload and load you up, we'll install the zone apparatus, put a compass on you, put one of yours on us, and then you can hop back up here where you're comfortable. Then as soon as we can get the 'Lark' ready for the trip, we'll jump up here and be on our way. Everything clear? Cut the rope, Mart—let the old bucket drop!"