Sine did as he was told, and the ship heeled over so that it presented its side to the sinister object, which was still invisible to the unassisted eye. While Kass watched it through the ampliscope, his companions stared through the thick ports at the velvet, gem-studded firmament. They could feel the attraction growing with terrifying speed. "It's turning with us," Kass announced, "and getting closer. If we can swing around it, it will be a very sharp ellipse indeed!" "Try and see if you can get a few more revs out of the screw," Lents suggested, and Sine crept forward, his powerful muscles straining against the pull. He lifted the leaden weight of his arm to the lever. He _must_ get a little more power out of the motor, or they would crash to their deaths in a few minutes! A fine ending for their daring dash to Jupiter--the first space flight since the great comet swarm of 800,768 A. D. Sine pulled back hard on the lever, and the motor gamely responded, moaned and shuddered under the tremendous overload. The tachometer needle quivered, began to climb, 52,000, 55,000, 56,000---- The ship gave a lurch--there was a dull grinding, a hollow, metallic groan. The men picked themselves up from the floor--realizing at once the fatal significance of the lack of effort required. Their movement carried them off the floor--made them grasp handholds. Floating free! That meant falling free! Sine glanced at the tachometer. The dead needle stood at zero. Through the forward window he could see one of the four screw blades, black, motionless. Lents, obeying the habits of a lifetime, elbow hooked in a handhold, was figuring the time required for them to strike. He looked up with a puzzled frown. "We should have struck about right now! Check on that body's position, will you, Kass?" * * * * * The bald-headed scientist pulled himself to the ampliscope. But it was possible to see the object through the ports now, quite plainly. It was black, cylindrical, glinting dully in the sun's light. The space ship was tumbling end over end, lazily, bringing the thing into view first at one port--then another. "No acceleration!" Kass reported, amazement mingling with hope. "Same speed--we may still hit--but no evidence of gravity. We're falling toward it on momentum alone!" Lents' brown eyes twinkled with perplexity in their pits of fat. "The force, whatever it is, doesn't seem like anything in nature. But if we're traveling on momentum alone we can pull away with our emergency rockets--though I hate to waste the fuel." Sine leaped to the rocket controls. "Grab handholds!" he snapped over his shoulder. The men rolled into the padded niches provided for that purpose. Sine's niche was so placed that it would not be necessary to lift a hand against the tremendous pressure of rocket acceleration. A lateral swing of the lever along its quadrant operated the rockets.