He looked at the controls all about him. One huge panel contained thousands of studs. He depressed one. From the far away opposite wall a ray of white light needled out and slightly downward. He swept his hand across more studs, and other beams lanced out from the four walls--dozens, then hundreds. Ketrik was satisfied. Here, he knew were the controlling rays which Vaajo had spoken of. He shut the rays off, and looked further about him. There was only the tele-vise, and two other instruments. One was merely a wheel, six feet in diameter. The other was a machine complicated beyond anything Ketrik had ever imagined. Giant tubes, coils, and alien looking grids nestled in the bulk of it. Cables thick as his arm led to the nearest wall, thence upward to the lower rim of the glassite dome, and completely around it. From there, other cables dangled downward for a few feet into empty space. Ketrik approached the control panel. It seemed simpler than he had supposed, but he studied it a while before reaching out a tentative hand to the first switch. The coils shrieked maddeningly, then the sound ascended the scale and passed beyond the audible. The giant tubes pulsed to life, throwing out a silver radiance. Then Ketrik reached out to what seemed to be a master-lever. He pulled it slowly toward him. There came a sound, a sighing, which rose to tremendous crescendo as though every wind from the depths of space were sweeping in upon him! An awful vertigo as the dome, the floor, and all space between seemed to tilt crazily--into _nothingness_! He clung to the lever, sought to push it back. His mind reeled. Everything before him was merging into a grotesquerie of impossible angles and planes--and through it all came a twisting vortex of darkness, utter emptiness, that sought to sweep him out and away! Then the lever gave before his surging muscles. It fell back into place. Everything came back to normal--except Ketrik. He allowed the dizziness to pass, and then grinning, he tried the stunt again! Two, three times more he tried it, with the same result, until he was quite sure of his mastery over that control. For here was the machine he had hoped to find! Here was the means and the only means, of ridding the System once and for all of that Entity which Dar Vaajo in his madness had built up into such a weapon; a terribly alive weapon which, if allowed to go unchecked, with or without Dar Vaajo, could well become a menace to all the worlds! Ketrik realized that his task had reached the crucial point. A single mistake now, a mere miscalculation, and all would be over. So far he had only seen a manifestation of the Entity, not the thing itself. But he knew it must be here, somewhere very close--and waiting.... He stepped over to the towering perpendicular wheel. * * * * *