With the data typed, the assistant, knowing that Don was trustworthy and that no scheduled arrivals would ensue, left the room in the young pilot’s charge while he departed to post his notes; and the chance they longed for was made for them.

The search of drawers in the radio table gave no result.

No other section of the drawer space seemed worth looking into, and since no visible evidence of any projection apparatus other than the airport equipment was seen, they felt that prying was useless.

“Nothing for the control chief to use—you see that!” argued Garry.

“I suppose you think he’d have everything standing right out for everybody to see?” Don spoke witheringly.

“Well, then,” Chick seemed inclined to take Garry’s side, to suspect the man who operated a theatre and, thereby, knew most about the projection of images from and through moving picture films.

Don sent his eyes from wall to wall, from cupboard of spare instruments to unlocked desk drawers.

“Tew is the one to blame,” Chick persisted. “Vance told the truth about that tracing; he put his initials on it by chance, the way I’d make little stars in my geography book when I’d try to memorize the capitals of the South-Central States.”

“But—oh, shucks! What’s the good. I don’t know who it is. I think the control man is more logical than Toby Tew—and I like Toby best, too!” Don said, morosely. “But what’s the good of a theory, any way you look at it, unless everything fits.”

The helicopter didn’t fit in with the idea of the control room man projecting a moving scene on a cloud, he argued against his own ideas: at the same time, the helicopter failed to connect a theatre owner and boatman with such an idea. The picture on a cloud could have been evolved by either, since both knew about the angles of projection and the properties of light, concentration, angle and diffusion. But Doc Morgan had also acted in a suspicious manner, and certainly knew about the treasure, which, in itself, failed to fit in with the theory of Tew trying to ruin airport business for spite against its executive.