needs a rest and doctoring up," thought the young inventor
as he turned the electric chandelier off by a button on the wall, in
order to darken the room, so that he might peer out to better
advantage. "I think he's been working too hard on his wireless motor.
I must get Dr. Gladby to come over and see dad. But now I want to find
out who that was under this window."

Once more Tom looked out. The moon had emerged from behind a thin bank
of clouds, and gave a little light.

"See anything?" asked Mr. Gunmore cautiously.

"No," whispered the youth, for it being a warm might, the windows were
open top and bottom, a screen on the outside keeping out mosquitoes and
other insects. "I can't see a thing," went on Tom, "but I'm sure--"

He paused suddenly. As he spoke there sounded a rustling in the
shrubbery a little distance from the window.

"There's something!" exclaimed Mr. Gunmore.

"I see!" answered the young inventor.

Without another word he softly opened the screen, and then, stooping
down to get under the lower sash (for the windows in the library ran
all the way to the floor), Tom dropped out of the casement upon the
thick grass.

As he did so he was aware of a further movement in the bushes. They
were violently agitated, and a second later a dark object sprang from
them and sprinted along the path.

"Here! Who are you? Hold on!" cried the young inventor.

But the figure never halted. Tom sprang forward, determined to see who
it was, and, if possible, capture him.

"Hold on!" he cried again. There was no answer.

Tom was a good runner, and in a few seconds he had gained on the
fugitive, who could just be seen in the dim light from the crescent
moon.

"I've got you!" cried Tom.

But he was mistaken, for at that instant his foot caught on the
outcropping root of a tree, and the young inventor went flat on his
face.

"Just my luck!" he cried.

He was quickly on his feet again, and took after the fugitive. The
latter glanced back, and, as it happened, Tom had a good look at his
face. He almost came to a stop, so startled was he.

"Andy Foger!" he exclaimed as he recognized the bully who had always
proved himself such an enemy of our hero. "Andy Foger sneaking under my
windows to hear what I had to say about my new aeroplane! I wonder what
his game can be? I'll soon find out!"

Tom was about to resume the chase, when he lost sight of the figure. A
moment later he heard the puffing of an automobile,