Tom laughingly desisted, and went up to his room.  He sat up a few minutes, writing a letter to a girl of his acquaintance, for, in spite of the fact that the young inventor was very busy with his own and his father’s work, he found time for lighter pleasures.  Then, as his eyes seemed determined to close of their own accord, if he did not let them, he tumbled into bed.

Tom fancied it was nearly morning when he suddenly awoke with a start.  He heard a noise, and at first he could not locate it.  Then his trained ear traced it to the dining-room.

“Why, Mrs. Baggert must be getting breakfast, and is rattling the dishes,” he thought.  “But why is she up so early?”

It was quite dark in Tom’s room, save for a little gleam from the crescent moon, and by the light of this Tom arose and looked at his watch.

“Two o’clock,” he whispered.  “That can’t be Mrs. Baggert, unless she’s sick, and got up to take some medicine.”

He listened intently.  Below, in the dining-room, he could hear stealthy movements.

“Mrs. Baggert would never move around like that,” he decided.  “She’s too heavy.  I wonder—­it’s a burglar—­one of the gang has gotten in!” he exclaimed in tense tones.  “I’m going to catch him at it!”

Hurriedly he slipped on some clothes, and then, having softly turned on the electric light in his room, he took from a corner a small rifle, which he made sure was loaded.  Then, having taken a small electric flashlight, of the kind used by police men, and sometimes by burglars, he started on tiptoe toward the lower floor.

As Tom softly descended the stairs he could more plainly hear the movements of the intruder.  He made out now that the burglar was in Mr. Swift’s study, which opened from the dining-room.

“He’s after dad’s papers!” thought Tom.  “I wonder which one this is?”

The youth had often gone hunting in the woods, and he knew how to approach cautiously.  Thus he was able to reach the door of the dining-room without being detected.  He had no need to flash his light, for the intruder was doing that so frequently with one he carried that Tom could see him perfectly.  The fellow was working at the safe in which Mr. Swift kept his more valuable papers.

Softly, very softly Tom brought his rifle to bear on the back of the thief.  Then, holding the weapon with one hand, for it was very light, Tom extended the electric flash, so that the glare would be thrown on the intruder and would leave his own person in the black shadows.  Pressing the spring which caused the lantern to throw out a powerful glow, Tom focused the rays on the kneeling man.

“That will be about all!” the youth exclaimed in as steady a voice as he could manage.

The burglar turned like a flash, and Tom had a glimpse of his face.  It was the tramp—­Happy Harry—­whom he had encountered on the lonely road.

CHAPTER XIX.