“Track clear?” breathed Johnny.

“All clear,” Pant whispered back.

“All right; here goes!”

There followed a series of sudden sharp explosions. These increased rapidly until they became a loud and insistent purr. Then, with the force and speed of a frightened pig, the little motor car shot forward.

The movement was too sudden for the boys. Johnny was thrown backward upon the floor. Pant, thrown in a wild whirl to the right, saw the motor, a black streak, shoot down the dark alley-way.

“She’s got speed,” he muttered.

The wild snorting of the motor awakened echoes in every corner of the factory. This was followed almost immediately by a deafening crash.

Pant started quickly forward, then paused. Johnny was now on his feet.

“Did she explode or hit the wall?” Pant asked.

“Hit the wall.”