"Blowout, by thunder!" they heard him call to his companions, as he piled out and ran to the wheel he thought had suffered the accident.
Jack obligingly slowed down so that the six, leaning far out and craning back at their victims, got the full benefit of their joke.
When he sped on they fell back into their seats and howled with glee.
It was funny.

They laughed and slapped one another on the backs, and the more they laughed the funnier it seemed.

They rocked with mirth, they bounced up and down on the cushions and whooped.
All but Jack.

He kept his eyes on the still-heaving asphalt, and chewed gum and grinned while he drove, with the persistent sensation that he was driving a hydro-aeroplane across a heaving ocean.

Still, he knew what the fellows were up to, and he was perfectly willing to let them have all the fun they wanted, so long as they didn't interfere with his driving.
In the back of his mind was a large, looming sense of responsibility for the car.