“How did you find that out!”
Don, at the table, took pencil and paper.
While he sketched rapidly Garry entered. Chick put him in possession of Don’s news.
Watching, Garry nodded.
“Don knew, from the light angle, I guess,” he whispered.
The sketch Don made was proof of his accuracy of judgment.
It showed a small airplane, as though viewed from above. Its nose was directed toward a sketchy line that indicated the shore of the bay.
A little in front of its nose Don had made a small indication of a cloud. On that he put a straight line, that the others saw was meant to represent the “screen,” or place where the picture had been seen.
And the airport control room when he sketched it in, lay at exact right angles to that screen line!
“As the nose pointed West,” Don said, excitedly, “the light from your projector, coming from the South, would have been on the South part of the cloud. But the picture was on the East side, the one I faced. That’s how I knew you didn’t throw the picture. Besides, as I saw earlier, the diffused light from your beam, as it touched a cloud before the picture appeared, was very faint!”