"It's the bell," said Jack. "I'm accused of taking it down and
putting it in Grimm's room. They found a rag with arnica on it near
the ding-dong, and Old Grimm jumped to the wrong conclusion, basing
his belief on what he saw here last night in the first-aid-to-the-
injured line. I've got until to-morrow to prove that I didn't do it."

"We can prove it easily enough," said Sam.

"Not so easily as you think," spoke Jack. "Grimm saw us out late, you
remember, and if all of you joined in saying it wasn't I who did it,
they wouldn't believe you. I guess they want to make an example of
someone. No sir, I'm going to do some sleuthing on my own hook. I've
got a good line and a bit of evidence to start with. I'm pretty sure
I can make some folks around here sit up and take notice about this
time to-morrow."

"Good for you, Jack!" exclaimed Dick. "If you want any help call on
us!"

"Thanks," replied Jack. "Now I guess we'd better get ready for
breakfast."

His chums left him to complete his dressing, and, when they were
gone, Jack carefully laid aside the spark plug Budge had given him.

"First link," he said.

During the noon intermission Jack had a short but earnest talk with
Socker, the school janitor. The latter nodded his head vigorously
several times during the conversation.