Suddenly the fellow shot up the cross-bars of an inclined conveyor track which led to the second floor. Suspended from a mono-rail above this conveyor track was an electrically controlled tram.
Was the electricity turned on? Johnny’s mind worked with the speed of a wireless. His muscles did its bidding. Leaping to the platform of the tram, he threw the lever back. So suddenly did the thing start forward that Johnny was all but thrown from the tram.
The next instant he caught his breath and threw in the clutch. He was not a second too soon, for had the tram traveled ten feet further it would inevitably have struck the racing stranger square in the back of his head.
“I want to catch him, not kill him,” muttered Johnny.
But the stranger was game. Leaping away to the right, he dropped through a hole in the floor in which there dangled a chain. Quickly he disappeared from sight.
Johnny followed, and, just as he touched the floor below, heard the hum of an electric motor.
Johnny knew at once what it was—a “mule,” as the workmen called the short, snub-nosed electric trucks used all over the shops for light hauling.
“I can’t catch him on a mule,” he groaned.
But again his face cleared. Just before him there stood another of the trucks. “A mule against a mule,” he smiled. “Now we’ll see who’s the best driver.”
The race, while wild and furious, assumed an almost humorous aspect; indeed, Johnny fancied that from time to time the stranger turned about and uttered a low chuckle. That was disconcerting, to say the least. Added to this was the growing conviction that he had met this fellow before, and that under more favorable circumstances.