pet machine. As he came in front, and saw the
propeller, he gave another exclamation. The fine wooden blades of
several layers, gracefully curved, which had cost him so much in
time and labor to build up, and then fashion to the right shape, had
been hacked, and cut with an axe. The propeller was useless!

"More of Andy's work," murmured Tom. "This is about the worst yet!"

There came over him a feeling of great despondency, which was
succeeded by a justifiable rage. He wanted to take after the bully,
and give him a merciless beating. Then a calmer mood came over Tom.

"After all, what's the use?" he reasoned. "Whipping Andy wouldn't
mend the BUTTERFLY. She's in bad shape, but I can repair her, when I
get time. Luckily, he didn't meddle with the engine. That's all
right." A hasty examination had shown this. "I guess I won't do
anything now," went on Tom. "I'll have my hands full getting Mr.
Fenwick's airship to run. After that I can come back here and fix up
my own. It's a good thing I don't have to depend on her for making
the trip to Philadelphia. Poor BUTTERFLY! you sure are in a bad
way," and Tom felt almost as if he was talking to some living
creature, so wrapped up was he in his trim little monoplane.

After another disheartening look at his air craft, the young
inventor started to leave the shop. He looked at a door, the
fastening of which Andy had broken to gain admittance.

"I should have had the burglar alarm working, and this would never
have happened," reasoned Tom. All the buildings were arranged so
that if any one entered them after a certain hour, an alarm would
ring in the house. But of late, the alarm had not been set, as Tom
and his father were not working on any special inventions that
needed guarding. It was due to this oversight that Andy was able to
get in undetected.

"But it won't happen again," declared Tom, and he at once began
connecting the burglar-apparatus. He went into the house, and told
his father and the engineer what had occurred. They were both
indignant, and the engineer declared that he would sleep with one
eye open all night, ready to respond to the first alarm.

"Oh, there's no danger of Andy coming back right away," said Tom.
"He's too frightened. I wouldn't be surprised if he disappeared for
a time. He'll be thinking that I'm after him."

This proved true, as Andy had left town next morning, and to all
inquiries his mother said he had gone to visit relatives. She was
n