He set a little tin can beneath the peculiar device of copper-tubing rings. The can was wholly ordinary, made of thin sheet-iron plated with tin as are all the tin cans of commerce.
“You have the catapult remade?” gasped Von Holtz. “Wait! Wait! Let me look at it!”
For one instant, and one instant only, Tommy let him see. The massed set of concentric rings, each one of them parallel to all the others. It looked rather like a flat coil of tubing; certainly like no particularly obscure form of projector. But as Von Holtz’s weak eyes fastened avidly upon it, Tommy pressed the improvised electric switch. At once that would energize the solenoid and release all the tensed springs from their greater tension, for an attempt to reach a permanent equilibrium.
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.