ed 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."

"Miss Nestor!" blurted out Tom, more surprised evidently to see his
acquaintance of the runaway again than she was at beholding him. "I
didn't know you ran a motor-boat," he added. "I don't," said she
simply and helplessly. "That's the trouble, it won't run."

"How comes it that you are up here?" went on Tom.

"I am stopping with friends, who have a cottage near the Lakeview
Hotel. They have a motor-boat and I got Dick Blythe--he's the owner of
this--to show me how to run it. I thought I knew, and I started out a
little while ago. At first it went beautifully, but a few minutes ago
it blew up, or--or something dreadful happened."

"Nothing very dreadful, I guess," Tom assured her. "I think I can fix
it." He got into the other boat and soon saw what the trouble was.
The carburetor had gotten out of adjustment and the gasoline was not
feeding properly. The young inventor soon had it in order, and,
testing the motor, found that it worked perfectly.

"Oh, I can't thank you enough," cried Miss Nestor with a flash from her
brown eyes that made Tom's heart beat double time. "I was afraid I had
damaged the boat, and I knew Dick, who is a sort of second cousin of
mine, would never forgive me."

"There's no harm done," Tom assured her. "But you had better keep near
us on your way back, that is, if you are going back."

"Oh, indeed I am. I was frightened when I found I'd come so far away
from shore, and then, when that explosion took place--well, you can
imagine how I felt. Indeed I will