So it was with rather a start of surprise that Tom saw a light in the structure where the butterfly was housed.

“I wonder if dad or Mr. Jackson can be out there?” he mused.  “Yet, I don’t see why they should be.  They wouldn’t be going for a flight at night.  Or perhaps Mr. Damon arrived, and is out looking it over.”

A moment’s reflection, however, told Tom that this last surmise could not be true, since the eccentric man had telegraphed, saying he would not arrive until the next day.

“Somebody’s out there, however,” went on Tom, “and I’m going to see who it is.  I hope it isn’t Eradicate monkeying with the monoplane.  He’s very curious, and he might get it out of order.”

Tom increased his pace, and moved swiftly but softly toward the shed.  If there was an intruder inside he wanted to surprise him.  There were large windows to the place, and they would give a good view of the interior.  As Tom approached, the light within flickered, and moved to and fro.

Tom reached one of the casements, and peered in.  He caught a glimpse of a moving figure, and he heard a peculiar ripping sound.  Then, as he sprang toward the front door, the light suddenly went out, and the young inventor could hear some one running from the shop.

“They’ve seen me, and are trying to get away,” thought the lad.  “I must catch them!”

He fairly leaped toward the portal, and, just as he reached it, a figure sprang out.  So close was Tom that the unknown collided with him, and our hero went over on his back.  The other person was tossed back by the force of the impact, but quickly recovered himself, and dashed away.

Not before, however, Tom had had a chance to glance at his face, and, to the chagrin of the young inventor, he recognized, by the dim light of a crescent moon, the countenance of Andy Foger!  If additional evidence was needed Tom fully recognized the form as that of the town bully.

“Hold on there, Andy Foger!” shouted the young inventor.  “What are you doing in my shed?  What right have you in there?  What did you do?”

Back came the answer through the night: 

“I told you I’d get square with you. and I’ve done it,” and then Andy’s footsteps died away, while a mocking laugh floated back to Tom.  What was Andy’s revenge?

CHAPTER IX

THE WHIZZER FLIES

For a moment, Tom gazed after the fleeting figure of the cowardly bully.  He was half-minded to give pursuit, and then, realizing that he could find Andy later if he wanted him, the young inventor decided his best plan would be to see what damage had been done.  For that damage would follow Andy’s secret visit to the shop, Tom was certain.

Nor was his surmise wrong.  Stepping into the building, the lad switched on the lights, and he could not repress an exclamation of chagrin as he looked toward his trim little monoplane, the butterfly.