to crawl inside, if only he
can find a window that's been left unfastened. Steady now, Thad;
he's stopped under one right now!"

They continued to crouch there and watch what went on, their eyes
glued upon the dimly seen figure of the unknown. Greatly to the
surprise of Thad, the party stepped to one side, and seemed to be
dragging back a heavy plank, not of any vast length, but sufficiently
long to reach the window when placed on a slant.

"Say, did you notice how he seemed to know just where that plank was
lying, Hugh?" asked Thad deliriously. "Seems like he must have been
spying out the land by daylight beforehand."

"You're right there," whispered Hugh; "and he acts as if he felt
pretty certain that particular window would be unfastened, in the
bargain."

"Hugh, that settles it," added the other sturdily, as though now
fully convinced.

"Yes, settles what, Thad?"

"Why, it's a _boy_, don't you see, and he must have left that
window unlatched on purpose this afternoon when some of the
fellows were shutting up."

"Wait and see," advised Hugh, although almost convinced of the same
thing himself.

The test was not long in coming. They could see the other "shinning"
up the sloping plank, as any athletic boy would be apt to do, without
any particular trouble. Now he had reached the window, and Thad held
his breath in suspense. He sighed as he heard a slight squeaking
sound. Evidently the sash which was supposed to be fastened every
night through ordinary prudence, had given way to his hand, when he
exerted some pressure.

"He's going in, Hugh!" Thad observed, again laying a quivering hand
on the arm of his comrade, and then following these words with a low
exclamation of startled wonder: "Oh! look there, what's that queer
glow mean?"

Hugh understood readily enough.

"Why, he's got one of those little handy electric torches, you see,
and is using it so as to get his bearings inside the building."

"Guess you're right, Hugh," admitted the other; "and there, he's
crawling over the sill now, as sure as anything. Oh! the skunk, what
can he be up to?"

"We'll try and find out," said Hugh, with his usual promptness. "Now
he's gone further from the window let's be moving along. That plank
ought to make it easy sledding for fellows like us."

Indeed, it would be hard to find a couple of more athletic boys than
Hugh and his chum. Their intense love for every type of outdoor
sport had kept them in s