Buck smiled slowly. He turned directly to McLaurin and replied: "Yes--the Strangers. As to developments--I can't tell, naturally. But if they do, it will be something entirely unexpected now. You see, given one new discovery, a half-dozen will follow immediately from it. When we announced that atostor, look what happened. Renwright must have thought it was God's gift to suffering physicists. He stuck some oxygen in the thing, added some of his own stuff--and behold. The magnetic apparatus gave us directly the shield, and indirectly this mirror. Now, I seem to have reached the end for the time. I'm still trying to get that space-release for high speed--speed greater than light, that is. So far," he added bitterly, "all I've gotten as an answer is a single expression that simply means practical zero--Heisenberg's Uncertainty Expression." "I'm uncertain as to your meaning"--McLaurin smiled--"but I take it that's nothing new." "No. Nearly four centuries old--twentieth century physics. I'll have to try some other line of attack, I guess, but that did seem so darned right. It just sounded right. Something ought to happen--and it just keeps saying 'nothing more except the natural uncertainty of nature.'" "Try it out, your math might be wrong somewhere." Kendall laughed. "If it was--I'd hate to try it out. If it wasn't I'd have no reason to. And there's plenty of other work to do. For one thing, getting that apparatus in production. The IP board won't like me." Kendall smiled. "They don't," replied McLaurin. "They're getting more and more and more worried--but they've got to keep the IP fleet in such condition that it can at least catch an up-to-date freighter." * * * * * Gresth Gkae looked back at Sthor rapidly dropping behind, and across at her sister world, Asthor, circling a bare 100,000 miles away. Behind his great interstellar cruiser came a long line of similar ships. Each was loaded now not with instruments and pure scientists, but with weapons, fuel and warriors. Colonists too, came in the last ships. One hundred and fifty giant ships. All the wealth of Sthor and Asthor had been concentrated in producing those great machines. Every one represented nearly the equivalent of thirty million Earth-dollars. Four and a half billions of dollars for mere materials. Gresth Gkae had the honor of lead position, for he had discovered the planets and their stable, though tiny, sun. Still, Gresth Gkae knew his own giant Mira was a super-giant sun--and a curse and a menace to any rational society. Our yellow-white sun (to his eyes, an almost invisible color, similar to our blue) was small, but stable, and warm enough.