The air was escaping in a prodigious geyser; unimpeded by an atmosphere, it spewed out, visible like a cloud due to its moisture, smooth like an inflating balloon without billows. The ball of vapor expanded swiftly toward the gray vastness of Jupiter 100,000 miles below, enveloping the fugitive ship for a time, then passing on, like an enormous milky white cloud, falling swiftly until it was lost in the darkness, still expanding. Overhead The Bubble continued serenely on its course, the sweeping curve of its crystal hemisphere visible. But now the actinic lights that had served as artificial suns were dark. The great man-made paradise was as cold and dead as the Earth's moon. Death stalked its pleasure palaces. Already up there the pleasant rippling lakes must be skimmed over with ice, the luxuriant vegetation stiff, crackling with frost. Despite the selfishness, the cruelty, the utter callousness of the First Race, Sine felt a pang of regret over the destruction of so much beauty. A messenger from the astrogator's cabin, a man whose skin was seared and scorched so that it looked like an alligator's hide, touched Lents' arm. "Jan would like to have you verify the course." There was apprehension in the man's voice. Member of a race so long enslaved, restrained, he feared the freedom of open space. They swept slowly past The Bubble, gaining speed. Suddenly there was a cry from the stern look-out: "The ship's heating. Stop it! Something's wrong." Sine, rushing to answer the call, found that the ship was indeed heating up. Shielded from the sun's rays as they were, this was inexplicable. And then he saw the dull red pinpoint of light. He had not seen it before, that patrol ship, clinging like a leech to the airlock of the crystal hemisphere. There had been men in there when the air escaped. They had been saved from death by the closing of their automatic airlocks. "Better get back into the shelter of The Bubble," he told Jan after a hurried trip to the astrogator's cabin. The spider man turned the vessel, and they scurried back to shelter. Although the patrol ship tried its gravity buttons on them, the Mugs had fully equipped their own vessel with similar, and larger buttons which were occasionally used in regulating the metal satellite's orbit. They could neutralize the other vessel's gravity force with ease. "And yet," Sine admitted to the serious little group in the cabin, as they once more floated in space under the immense sphere, "they seem to have us stymied." "Suppose they follow us around here?" Kass asked somewhat nervously.