"How do you figure that?" blurted Seaton. "Because of the acceleration they can stand. Nothing even semi-human, and probably nothing living, could endure it otherwise. Right?" "Yes--I never thought of that." "Furthermore, they are far from home, for if they were from anywhere nearby, the Osnomians would have known of them--particularly since it is evident from the size of the vessel that it is not a recent development with them, as it is with us. Since the green system is close to the center of the Galaxy, it seems reasonable, as a working hypothesis, to assume that they are from some system far from the center, perhaps close to the outer edge. They are very evidently of a high degree of intelligence. They are also highly treacherous and merciless...." "Why?" asked Dorothy, who was listening eagerly. "I deduce those characteristics from their unprovoked attack upon peaceful ships, vastly smaller and supposedly of inferior armament; and also from the nature of that attack. This vessel is probably a scout or an exploring ship, since it seems to be alone. It is not altogether beyond the bounds of reason to imagine it upon a voyage of discovery, in search of new planets to be subjugated and colonized...." "That's a sweet picture of our future neighbors--but I guess you're hitting the old nail on the head, at that." "If these deductions are anywhere nearly correct, they are terrible neighbors. For my next point, are we justified in assuming that they do or do not know about the zone of force?" "That's a hard one. Knowing what they evidently do know, it's hard to see how they could have missed it. And yet, if they had known about it for a long time, wouldn't they be able to get through it? Of course it may be a real and total barrier in the ether--in that case they'd know that they couldn't do a thing as long as we keep it on. Take your choice, but I believe that they know about it, and know more than we do--that it is a total barrier set up in the ether." "I agree with you, and we shall proceed upon that assumption. They know, then, that neither they nor we can do anything as long as we maintain the zone--that it is a stalemate. They also know that it takes an enormous amount of power to keep the zone in place. Now we have gone as far as we can go upon the meager data we have--considerably farther than we really are justified in going. We must now try to come to some conclusion concerning their present activities. If our ideas as to their natures are even approximately correct, they are waiting, probably fairly close at hand, until we shall be compelled to release the zone, no matter how long that period of waiting shall be. They know, of course, from our small size, that we cannot carry enough copper to maintain it indefinitely, as they could. Does that sound reasonable?"