Ray sighed and gave up. Martians had replaced Scotchmen in the lexicon of thrift, but Urushkidan set some kind of new record. He sat down in the pilot chair and started the atomic generator on high level conversion. "I hope it works," he muttered nervously. His fingers moved over the improvised control panel for the star drive. "Hang on, folks, here goes nothing." "Nothin," said Dyann after a long silence, "is correct." "Oh, lord! What's the matter now?" Ray went back to the new engine. Its circuits were alive, tubes glowed and indicators blinked, but the boat sat stolidly where it was. "I told you not to use tose approximations," said Urushkidan. Ray fiddled with the main-drive settings. "It's like any other gadget," he complained. "You sweat yourself dry designing it from theory, and then you have to tinker till it works." He began changing the positions of resistors and condensers, cutting sections out of the circuit to work on them. Urushkidan shredded a piece of paper, wetted it, and tried to smoke it. "Ray!" Dyann's voice came sharp and urgent from the forward cabin. "I saw a rocket flare." "Oh, no!" He sprang back to her and peered into the night sky. A long trail of flame arced across it. And another, and another-- "The Jovians," he groaned. "They've found us." "They may not see us," said Dyann hopefully. "They have metal detectors. We're done for." "Vell, ve can only die vunce. Kiss me, sveetheart." Dyann folded Ray in one arm while the other reached for her sword. The patrol rockets went over the horizon, braking, and swam back. Blast-flames spattered off the valley floor and frozen-gas vapors boiled furiously up toward mighty Jupiter. The boat telescreen blinked its indicator light. Numbly, Ray tuned it in. The lean hard face of Colonel Roshevsky-Feldkamp sprang into its frame. "Ah, there you are," said the Jovian. "If we surrender," said Ray, "will you give us safe conduct back to Earth?" "Certainly not. But you may be allowed to live." Urushkidan spoke from the lab. "Ballantyne, I tink te trouble lies in tis square-wave generator. If we doubled te boltage--" * * * * * The first patrol ship sizzled to a landing. Roshevsky-Feldkamp leaned forward till his face seemed to project from the screen and Ray had a wild desire to punch its nose. "So you've been working on our project." He said, "Well, so much the more labor spared us." Dyann cut loose with a short-range blaster she had located somewhere on the lab ship. "Urushkidan will die before he surrenders to you," said Ray belligerently. "I will do noting of te sort," said the Martian. Experimentally, he cut the square-wave generator back into the circuit and turned a dial. The boat lifted off the ground. "Hey, there," roared the colonel. "You can't do that!" The Jovian soldiers who had been pouring from the grounded ship looked stupidly upward. "Shell them!" snapped the colonel.