Mart became aware that he was holding his breath for the sound of a distant explosion. Yes, from whatever point Tar Norn could have hidden his hostage, the sound of a pound of uranite exploding would carry back to Comprotown. He sat down at his desk again. In front of him were the signed clearance papers for the freighters. In half an hour he'd take out the papers for the first freighter. But before that half hour was up-- He twisted a pencil between his fingers, held himself rigid to keep from turning and looking at the chronometer again. It hadn't been over a minute since he sat down--why torture himself by looking again? But each minute now seemed both a flash and an eternity. He turned over the sheaf of papers and drew a little square on the blank reverse side of the bottom one. That was Comprotown. He made a dot an inch or two away. That was the point where Tar Norn's ship had wrecked itself in landing. He drew a line from the point to the square. That was Tar Norn coming in to the town. That would have been about ten hours ago. Then, from the information about Callisto and Comprotown that had been in the papers in Tar Norn's ship, the pirate had found the home of the director. He would have had no trouble finding Leah's room. Venusians could see in the dark and walk as silently as cats. He would undoubtedly have drugged Leah into unconsciousness, probably without awakening her, since there had been no sign of a struggle. He'd put her into the lightweight spacesuit. Why? Undoubtedly it indicated that she would be outdoors. During the Callisto day, it would have been unnecessary. But an unconscious Earthwoman would freeze to death in the cold dark period of Callisto's eclipse behind Big Jupe. What then? The Venusian left, carrying her-- [Illustration: _The Venusian had carried the drugged girl into the night._] He threw down the pencil and began to pace the room again. His muscles were tense from listening. How many minutes? He didn't want to know; dared not look. But Tar Norn must have planned it all before he left the wrecked ship. Otherwise he wouldn't have taken the timer and-- Would he have rigged the time-bomb first, or after he had kidnapped Leah? And how? The timer itself would not have provided the concussion to set off the uranite. He'd have needed a battery, a spark-coil, and-- _But Venusians weren't mechanics._ They didn't understand machines, or electricity, or even simple clockworks, brilliant as their strange minds were in other ways. Tar Norn could have set the timer all right. For that matter, he could calculate an orbit and make settings for space flight. But he couldn't have made a time-bomb, even with the timer. He couldn't have rigged a circuit that would set off a cap! And, Mart realized suddenly, the timer itself would be an electrical--not a clockwork--gadget. Once disconnected from the now broken dynamo of the ship, Tar Norn couldn't have made it run at all!