“Open that leather case.”
It was only snapped shut, not locked. Chick and Garry got back the lid in short order.
“Here’s a roll of film.” Chick drew it out, opening the tin container protecting the celluloid material from drying out or from chance of fire. “It’s—an—aviation scene——”
“And the key to the locker was in the chief’s vest!” chanted Garry. “Your theory was right, Don.”
“I’m not so sure!” Don looked from the film to the projector. “It looks black for him, but—Garry how would you concentrate enough light from the big, open spot lantern here, onto the aperture of the projector head? See! The lens in that spot lamp is at least eighteen inches across, and that’s the diameter of the beam it throws. The part of the projector that the light has to concentrate on is less than two inches across! How about it?”
“I can’t tell you.”
“It was your theory, Don,” Chick reminded him. “Now you’ve got ‘evidence.’ You find out how it’s used.”
“I will!” Don accepted the challenge.
Studying the situation, the lighting conditions, and the materials at hand, he jumped up, turning an excited face to his comrades.
“This is how I’ll prove my theory—or test it, anyway,” he asserted. “Chick, rush down to the designing room, and get the big focusing cloth you use to cover your head when you have to focus the enlarging camera for detail print enlargements. Bring it up.”