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.