"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 compa.s.s 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 s.p.a.ce-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 s.p.a.ce. 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 s.p.a.ce-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 s.p.a.ce. 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 antic.i.p.ated as much resistance as we could offer with s.p.a.ce-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. "n.o.body 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 quant.i.ties 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...o...b..t, 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 ma.s.ses, and will have opposite and approximately equal velocities; hence the resultant fused or gaseous ma.s.s 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 quant.i.ties 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, d.i.c.k! 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-c.o.c.ked 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, d.i.c.k, they couldn't possibly. Would they kill them all, d.i.c.k?

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."

"d.i.c.k, 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, d.i.c.k," 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' compa.s.s."

"Why sure," a.s.sented 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 a.s.sortment 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 compa.s.ses 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, d.i.c.k--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, d.i.c.ky," 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-compa.s.ses 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."