“If—if those girls waved a handkerchief out of the openings, nobody could see it down here,” thought the conscience-stricken youth.

He had never been up in the tower himself, for it was forbidden territory. So he did not know how wide the windows were. It just struck home to Master Purt Sweet that the girls would be unable to signal their situation to anybody.

But he had reached home before these thoughts so troubled him that he felt as though he must undo what he had done. Perhaps John had not gone home yet. He might still be able to get into the building, creep upstairs, unlock the door of the tower, and then run out before the girls could catch and identify him.

For Purt had a very strong desire not to be suspected in this matter. Chet Belding would take up cudgels for his sister in a minute; and Chet would, Purt was sure, thrash him most soundly!

Any of the teachers would have a pass-key to the building. Purt remembered that fact, too. Could he prevail upon one of them to lend him a key so that he could go into the building? Of course, he must have some good excuse, and he feared to appear before Professor Dimp with any such request unless he could back it with sound reason. And Mr. Sharp was entirely out of the question. Purt knew that the principal of Central. High would see right through him instantly.

As for the lady teachers, Purt was more afraid of them than of Mr. Dimp and the principal. As it grew dark the boy sat cowering in his room at home, from the window of which he could see dimly the outlines of the schoolhouse tower, and he wept a few tears.

He would have given a good deal had he not turned the key in that lock!

Purt didn’t feel that he could appear at the dinner table; so he gave an excuse to his mother’s maid, and went out again. Perhaps somebody had discovered the girls up in the tower and released them. He walked up Whiffle Street and saw Chet Belding hanging over the front gate.

“Hullo, Purt!” exclaimed the big fellow. “What’s doing?”

“No—nothing,” stammered Purt.