Morrow sat up in the co-pilot's seat beside Smitty as they drove steadily through the darkness. Above, the stars twinkled coldly in the black heavens and the white sickle of a quarter-moon threw its milky glow into the control pit. Below, rolling gray stretches of meadow spread out between dark, timber-clad shoulders and humps of the Sierras. To the East, the timber gave way to rocky, cloud-wreathed peaks. They were headed toward them, and climbing. "Five thousand on the altimeter," Smitty remarked flatly. "That's ten thousand, five hundred above sea-level. She isn't levelling out yet." His face was grim in the green glow of the instrument dials. Behind them, the black, glinting hull was crammed with sandbags. They were lifting a full load. Morrow kept his gaze fixed on the air-speed indicator. A deep, whooming sound came from the tail-jets. The needle on the indicator dial flickered restlessly, back and forth, over a single point. They were doing forty miles an hour, indicated air-speed. They hadn't been able to increase that speed. A brisk twenty-five-mile-an-hour wind was blowing them steadily southward off their course. Smitty shook his head. "Those jets don't even _sound_ right, Bill--" "I know," Morrow said. He sighed wearily. "We've got to do better than this. Take her higher--ram-jets are supposed to work better at high altitude." "I don't want to go over twelve thousand without oxygen," Smitty replied. "Can't let this wind blow us down over Yosemite National Park, either--if we can help it." "Take her up," Morrow said. The ship continued to rise, steadily. "Eleven thousand," Smitty chanted. "Eleven thousand five hundred, twelve thousand, twelve thousand five--she's flattening out!" Their ascent slowed, gradually. The ship steadied at thirteen thousand feet above sea-level--7500 feet on the altimeter, which had been zeroed to the altitude of their sawmill workshop. "Down!" Morrow barked. "She's losing speed!" The indicator needle was creeping back past thirty-five, then thirty--their sideward shift to the south could be felt. Smitty shoved forward his control wheel. The ship dived. They glided easily back across the mountain slope toward their sawmill. Judging their wind-drift accurately, Smitty set the ship down in the yard before the black, yawning doors of the building. As the runners scraped the ground, he switched off the gravitors and slumped back in his seat, dejectedly. "We've got to rebuild that jet chamber," he muttered. "There's something wrong with it, Bill. All we've got is a big wind-blower, in spite of her weightlessness--the drag of the hull wouldn't slow us down _that_ much!" Morrow unbuckled his seat-belt, rose, and strode back to the steps without a word.