“Look out!” laughed Jack, “you’ll have another tumble if you aren’t careful, Zack.”

“Oh, you make me tired,” grunted the infuriated lad. But he turned away and tried no further hostilities.

“If you want us to, we’ll tow your machine back to town,” volunteered Jack, who felt that there was, perhaps, some excuse for Zack’s anger; “we’re going that way.”

“Then go on, and be quick about it,” shouted Sam furiously. “I guess I can tow the machine in just as well as you fellows.”

“Oh, all right. If that’s the way you feel about it, we’ll be getting on,” said Jack. As he spoke he climbed back into the Flying Road Racer, followed by Tom. He backed the machine away from the wreck and noted, at the same time, that the engine hood had been slightly dented by the impact. But the motor itself was not affected and buzzed away in a lively fashion.

As soon as he had the Flying Road Racer clear of the wreckage, Jack set his lever ahead and the big machine moved off, no further words being exchanged between the cousins and the two boys, who now, clearly enough, chose to regard Jack and Tom as their enemies. As the Flying Racer glided away, Sam, yielding to a sudden impulse of fury, stooped down. He picked up a stone and hurled it with all his might at the two occupants of the land-and-air machine.

Had it struck the mark for which it was intended, the consequences might have been serious. But it whizzed harmlessly by Jack’s ear, avoiding him by a fraction of an inch.

“The coward,” cried Tom wrathfully; “shall we go back and give them a good pummeling?”

Jack shook his head.

“No, leave them alone,” he said. “After all, I’m afraid we didn’t appear to be very sorry over the wreck of that contrivance of Zack’s. He had a right to feel mad, I guess.”