"My investigation is practically complete," replied the First of Psychology, gravely. "I have explored many Fenachrone minds, and without exception I have found them chambers of horror of a kind unimaginable to one of us. However, you are not interested in their psychology, but in facts bearing upon your problem. While such facts were scarce, I did discover a few interesting items. I spied upon them in public and in their most private haunts. I analyzed them individually and collectively, and from the few known facts and from the great deal of guesswork and conjecture there available to me, I have formulated a theory. I shall first give you the known facts. Their scientists cannot direct nor control any ray not propagated through ether, but they can detect one such frequency or band of frequencies which they call 'infra-rays' and which are probably the fifth-order rays, since they lie in the first level below the ether. The detector proper is a type of lamp, which gives a blue light at the ordinary intensity of such rays as would come from space or from an ordinary power plant, but gives a red light under strong excitation." "Uh-huh, I get that O. K.," said Seaton. "Rovol's great-great-great-grandfather had 'em--I know all about 'em," Seaton encouraged Drasnik, who had paused, with a questioning glance. "I know exactly how and why such a detector works. We gave 'em an alarm, all right. Even though we were working on a tight beam from here to there, our secondary projector there was radiating enough to affect every such detector within a thousand miles." * * * * *