“If that’s what it was,” agreed Smithers. “I worked it for the Professor.”
Tommy leaned close and whispered:
“You never made any gears of that. But did you make some springs?”
“Uh-huh!”
Tommy grinned joyously.
“Then we’re set and I’m right! Von Holtz wants a mathematical formula, and no one on earth could write one, but we don’t need it!”
Smithers rummaged around the laboratory with a casual air, acquired this and that and the other thing, and set to work with an astounding absence of waste motions. From time to time he inspected the great catapult thoughtfully, verified some impression, and went about the construction of another part.
And when Von Holtz did not return, Tommy hunted for him. He suddenly remembered hearing his car motor start. He found his car missing. He swore, then, and grimly began to hunt for a telephone in the house. But before he had raised central he heard the deep-toned purring of the motor again. His car was coming swiftly back to the house. And he saw, through a window, that Von Holtz was driving it.
The lean young man got out of it, his face white with passion. He started for the laboratory. Tommy intercepted him.