The green line wriggled and changed form. Slowly, as the physicist manipulated the controls, the green line stopped moving.
"There!" shouted Wolstadt, "that is the wave form we want!" He reached over toward a switch. "Check your meters, Magruder!"
The assistant carefully adjusted the recording instruments of the huge machine that filled half the laboratory. "All right, Dr. Wolstadt, we're ready."
"Good!" Wolstadt pressed the switch.
The assistant watched the meters and automatic graphs.
"I'm afraid it didn't work, sir," he said at last. "The instruments aren't reacting as you expected."
Wolstadt shrugged resignedly. "Nevertheless, I think we are on the right track. Come, my boy, we will try again."
He shut off the machine.
The machine hadn't done what the scientists had expected of it, but it had another effect which was entirely unknown to them. During the few seconds of operation, an invisible ray had been beamed out of the machine. At the speed of light, the ray went through the wall of the lab and into Dr. Wolstadt's study. Like an X-ray, it went through the books and references on the physicist's desk. In a straight line, it shot out of the laboratory, silent and invisible. A mile or so farther on, it struck the Pentagon Building and went through. Among other things, it went through a complete copy of the Encyclopedia Brittannica, Roget's Thesaurus, the Oxford Unabridged Dictionary, a twenty volume set of The History and Analysis of Military Tactics, and a copy of Amazing Stories that some general had left on his desk.
Like a flashlight going through plateglass, the beam went through files, papers, memorandums, abstracts, reports, desks, chairs, brick, stone, and concrete. Through the Pentagon and across the Potomac it went, through building after building, unnoticed and invisible.