"I've seen him before, and yet he didn't look like that," thought the young inventor. "It's different, somehow. Now why should my memory play me a trick like this? Who in the world can he be?"

Tom straightened up, and tossed a monkey wrench into the tool box.

"Get everything fixed?" asked the stranger.

"I think so," and the young inventor tried to make his answer pleasant. "It was only a small break, easily fixed."

"Then you'll be on your way again?"

"Yes. Are you ready?" called Tom to Mr. Damon.

"Bless my timetable, yes! I didn't think you'd start back again so soon. There's one young fellow up there who has looped the loop three times, and I expect him to fall any minute."

"Oh, I guess he knows his business," Tom said easily. "We'll be getting back now."

"One moment!" called the man. "I beg your pardon for troubling you, but you seem to be a mechanic, and that's just the sort of man I'm looking for. Are you open to an offer to do some inventive and constructive work?"

Tom was on his guard instantly.