Bob, craning his neck, staring up toward the great banks of clouds which the early sun was painting with rosy fire, looked puzzled.
“Come to think of it,” he said, “we ought not to hear it at all.”
“Why not?” demanded Curt.
“He ought to be too far away.”
“How do you make that out?” Al was incredulous.
“Easy! Lang came home a little before daybreak. He had been at the airplane plant all night, with the ‘mechs’ because Mr. Tredway wanted to get that Silver Flash ready for delivery in a rush. I didn’t go to sleep again. I got up, and dressed and went out to tighten the handlebar on my bicycle. I glanced up, just as day broke, at the little windsock I have on our roof.”
“The wind was directly West.”
“I don’t see—” began Al; but Curt, wetting the back of his hand, tested the air in various directions.
“You use your head, Bob,” he said admiringly. “The breeze is pretty strong, and it has shifted around to South, straight from the Equator.”
“Are you two trying to be mysterious?” Al was a little bit annoyed.