V Ripon was still staring out the control room window at the disc of the Moon ahead of them. His voice came somberly as he spoke without turning around. "What's the speed now?" "Eleven hundred. Velocity of escape is twenty-five hundred." "Y'know, Larry, it seems one of Fate's little ironies that the only hope of saving the people of Earth from the Gray Death lies with this creaking ship and her polyglot crew! Oh--I have no illusions about the forlornness of our hope! We have no right to get through. But I'm not entirely a fool, and I have a few aces in my sleeves. I guess it's time to try out my magnetron controls. Stand by to cut rocket motors!" Ripon moved to several strange-looking control boxes that had been set up at one side of the room. Instrument dials glowed into light as he threw a switch, and there came a faint hum. "These tubes are the Magnetron Oscillators," Ripon said. "These switches control the magnetic converters. This other bank governs the selectors." "But I don't get the general principle," Larry said. "It's simply a selective utilization of the lines of magnetic force that fill outer space. This ship is naturally para-magnetic, so that she is easily permeable by the lines of force. By charging the wires outside the hull I can make all or part of the ship diamagnetic. Furthermore, I can change its charge so that the lines will draw in either direction." "I know enough of the general principles of magnetism to understand that," Larry said. "You can vary the direction of the effect, and perhaps vary the dynes. But...." "This indicator shows the hysteresis loop, the lag of magnetic indication behind the magnetizing force at any particular time," Ripon continued. "The heart of my system is the group of selectors and amplifiers set up in the compartments directly below us. With them I can select the magnetic currents suited to our course, and amplify them till they move the ship along with them just as the lines of magnetic force move iron filings about a bar magnet. At least," he said with a sudden flash of his reckless smile, "that's what I think I can do. If not, we'll probably never be heard of again. You'd better hope I'm right, young feller!" Ripon's craggy profile with its jutting beard was silhouetted against the moon as he bent over his dials and switches. Twice he checked them, then he lifted one hand. "Ready--cut rockets!" he snapped. Larry threw over the lever of the engine room indicator, and the roar of the rockets abruptly ceased.