“That he is an eccentric man, but very clever,” rejoined Jack. “I’m quite anxious to see this wonderful gun of his.”

“So am I,” said Tom, with equal eagerness, “if he has invented one that will shoot straight upward on an absolutely vertical line, he has a marvelous invention. Several inventors have been at work on the problem of getting out a gun that will really be effective against aëroplanes, but none has yet been found.”

“Well, I hope we can give Mr. Peregrine some good suggestions,” said Jack, as they reached the house and Mrs. Jarley announced that lunch was ready.

CHAPTER III—A FLYING MACHINE IN TROUBLE

On returning to the Flying Road Racer’s shed that afternoon, the lads’ ears were saluted by a buzzing, roaring sound that they instantly recognized.

“Somebody’s started up the motor!” exclaimed Jack, in a voice in which anger mingled with astonishment.

“That’s right,” echoed Tom indignantly, “wonder who on earth it can be?”

“Come on, let’s hurry up and find out,” and Jack started on a run for the shed.

As he reached the door, clouds of blue smoke met him. The vapor almost choked him. Whoever was tampering with the motor had neglected to pay much attention to the lubricating devices, with the result that the fumes of burning oil filled the air.

“Oh, hello, Jack Chadwick. I—you see—I thought you wouldn’t mind me looking at your machine,” exclaimed a lad of about Jack’s own age, as the indignant young inventor burst into the shed with Tom close on his heels.