The other craft did not appear to be moving very rapidly and the
ARROW was soon overhauling it. As the two chums came nearer they
could hear the puffing of the motor. Tom listened with critical
ears.

"That machine isn't working right," he remarked to his chum.

At that moment there sounded a loud explosion from the other boat
and at the same time there came over the water a shrill cry of
alarm. "That's a girl in that boat!" exclaimed Ned. "Maybe she's
hurt."

"No, the motor only backfired," observed Tom. "But we'll go over
and see if we can help her. Perhaps she doesn't understand it.
Girls don't know much about machinery."

A little later the ARROW shot up alongside the other craft, which
had come to a stop. The two lads could see a girl bending over
the motor, twirling the flywheel and trying to get it started.
"Can I help you?" asked Tom, shutting off the power from his
craft.

The young lady glanced up. Her face was red and she seemed ill at
ease. At the sight of the young inventor she uttered an
exclamation of relief.

"Why, Mr. Swift!" she cried. "Oh, I'm in such trouble. I can't
make the machine work, and I'm afraid it's broken; it exploded."