Borisu glowered darkly. "That is a story too long to tell in its entirety. But a portion I _will_ tell you that you may die realizing the implacable enmity of all Magogeans. "It is a story which goes back many years--as we measure time in the true universe. Many millenia of your brief solar time. "In true space once existed side by side two universes. That of our mother sun, which you call Sirius, and that of your parent star--Sol. Life spawned on the planets of these two systems; human life evolved. Men similar to you and me grew in stature and wisdom, developed civilizations, cultures. "All this was long ago. For ages untold each planet lived in ignorance of its neighbors. But some two hundred years ago--I measure chronology now in Universal Constant time, which is the only true measurement--that race of azure-tinted humans who peopled Sol's fifth planet--" "The predecessors of the Jovians?" "Yes, they. The Gogeans they called themselves, for the name of their world was Gog. Their science discovered, as has recently your Earthly science re-discovered, space travel. Their employment of this knowledge was a parallel to your own. They ventured, explored, expanded. They colonized, transporting their people to the other worlds of your sun. They set up outposts, carrying their superior culture to every habitable world. So potent was their rule, so all-embracing their lordship, that all the other planets' creatures they made slaves, shuttling them back and forth between the worlds as they had need of them." * * * * * Dr. Kang interrupted, "Then my theory was right, at least in part? Space travel _is_ responsible for the commingling of planetary types." "Yes," nodded Borisu. "And had the Gogeans gone no farther than this, their worlds might still exist. Their people might still be a great people instead of the decadent sprinkling we met on Jupiter. "But they were not content with draining the wealth of one solar system. No, they must venture afar. So Gogean space-vessels, a mighty armada of them, came to our neighboring system, there by weight of superior science wreaked havoc on our cities, slew our brave warriors and set themselves up as rulers not only of their system but of our own. "But their tyranny was short-lived. Though our race had not solved the secret of spaceflight, still our scientists possessed a vast knowledge. They turned to the construction of a weapon which should overthrow the interlopers. You know the result, because you have experienced it. Our scientists discovered an all-penetrating ray with the power of contracting the molecules of anything upon which it was turned. In brief, a 'dwindling' ray which projects what you Earthmen call gamma or cosmic rays.