And suddenly, Tayne's voice grated, "You had better drop the sword, Blair." There was the tightness of pain in his words, but they were clear. "I refuse to invert the ship. If we are to land, it must be inverted in sixty seconds. If you kill me, you kill yourself, for you do not know how to operate the panel beyond what you have seen--and you have not seen the operation for inversion. If you give me the sword, you will land alive." "You're out of your head, Mr. Tayne! I'm Senior Quadrate Blair, remember? I know how to operate the panel as well or better than you do. Get going!" He dug the tip deeper, and fresh blood started. But, Tayne's fingers remained immobile. "Mad or sane, Senior Quadrate Blair or--or something else, if you knew how to use the panel, you would not have taken the risk of forcing me to do it! I would already be dead--" There was a sudden, empty space in Doug's stomach. "Thirty seconds, Blair." The white mass of the sky was scant miles below them. He would need all of the thirty seconds, and there was no time to think--only time to realize that if he were to live, he must kill Tayne. It was like that time so long ago on the beaches of Normandy.... With all his strength he plunged the sword through Tayne's neck. And his own hands were at the control panel before Tayne's gurgling corpse had slumped to the deck. The life-blood seeped from it far more slowly than the seconds slipped beneath Doug's taut fingers. Not the buttons, not the dials, for he had seen them. But part of the panel itself--it had to be! The panel _itself_! He pressed one side, the other. Nothing. Ten seconds perhaps.... The bottom or the top next. But which? If it moved on a lateral axis--that would be it, for elevation or depression from the horizontal! But to accomplish what would amount to a half-loop.... He pressed the top of the panel. And it gave beneath his touch. In the viewscreen, the white mass which rushed to envelop him seemed to shift-- Further down--that was it, all the way around! Slowly, against an unseen source of pressure, he revolved the panel a half-revolution about its lateral axis. Already he could see its reverse side--on it in the same pattern there was an identical set of control buttons, dials. In the viewscreen there was a half-second's glimpse of the blackness of Space before the inverted ship tumbled tail-first into the white ocean of the Venus sky. And again there was the awful sensation of falling through infinity. Desperately, he pushed the top button. CHAPTER XVII He locked the top button at full depression and struggled to keep his legs straight beneath him, braced as they were now against a bulkhead which but a few minutes before had been, not a floor, but a wall. The ship's gyro system was no longer functioning as a pseudograv unit, but rather as a vertical stabilizer, and the second dial said four gravities.