As Von Holtz and the blue-jowled man stared, the little tin can leaped upward into the tiny coil. The small copper rings twinkled one within the other as the springs operated. The tin can was wrenched this way and that, then for the fraction of a second hurt the eyes that gazed upon it--and it was gone! And then the little coil came spinning down to the work bench top from its broken bearings and the remaining copper rings spun aimlessly for a moment. But the third ring of whitish metal had vanished utterly, and so had the coiled-wire springs which Von Holtz had been unable to distinguish. And there was an overpowering smell of ammonia in the room. * * * * * Von Holtz flung himself upon the still-moving little instrument. He inspected it savagely, desperately. His full red lips drew back in a snarl. "How did you do it?" he cried shrilly. "You must tell me! I--I--I will kill you if you do not tell me!" The blue-jowled man was watching Von Holtz. Now his lips twisted disgustedly. He turned to Tommy and narrowed his eyes. "Look here," he rumbled. "This fool's no good! I want the secret of that trick you did. What's your price?" "I'm not for sale," said Tommy, smiling faintly. The blue-jowled man regarded him with level eyes. "My name's Jacaro," he said after an instant. "Maybe you've heard of me. I'm from Chicago." Tommy smiled more widely. "To be sure," he admitted. "You were the man who introduced machine-guns into gang warfare, weren't you? Your gunmen lined up half a dozen of the Buddy Haines gang against a wall and wiped them out, I believe. What do you want this secret for?" The level eyes narrowed. They looked suddenly deadly. "That's my business," said Jacaro briefly. "You know who I am. And I want that trick y'did. I got my own reasons. I'll pay for it. Plenty. You know I got plenty to pay, too. Or else--" "What?" "Something'll happen to you," said Jacaro briefly. "I ain't sayin'' what. But it's damn likely you'll tell what I want to know before it's finished. Name your price and be damn quick!" Tommy took his hand out of his pocket. He had a gun in it. "The only possible answer to that," he said suavely, "is to tell you to go to hell. Get out! But Von Holtz stays here. He'd better!" CHAPTER IV Within half an hour after Jacaro's leaving, Smithers was in the village, laying in a stock of supplies and sending telegrams that Tommy had written out for transmission. Tommy sat facing an ashen Von Holtz and told him pleasantly what would be done to him if he failed to make the metallic ammonium needed to repair the big solenoid. In an hour, Smithers was back, reporting that Jacaro was also sending telegrams but that he, Smithers, had stood over the telegraph operator until his own messages were transmitted. He brought back weapons, too--highly illegal things to have in New York State, where a citizen is only law-abiding when defenseless. And then four days of hectic, sleepless labor began.