sat most of the boys of
the Third Form, was in a state of great disorder, while the discussion
of some topic of unusual interest seemed to be occupying the attention
of the prefects. It was not, however, until after the boys had swarmed
out of the dining-hall that the reason of this subdued commotion became
generally known; and then, like the sudden report of an explosion, every
one seemed to become acquainted with the news at the same moment.
Mr. Grice had been screwed up in his bedroom! Oaks and Allingford had
done it! The doctor had summoned them to meet him in his study!

It was from a member of the Third Form that the Triple Alliance heard
the particulars of what had happened. "'Little Grice,'" said this young
gentleman, whose own height was about four feet two inches--"'little
Grice' never turned up until just before the bell rang for prayers, and
then he was simply bursting with rage, and told us all about it. They'd
put a note under his door telling him to be in time by the school clock;
and besides that, when one of the men went to get him out, he found a
screw-driver with Oaks's name on, so it's as clear as day who did it."

This conversation took place in the quadrangle. Travers, the Third Form
boy, rushed off to impart his information to other hearers, and the
three chums passed on through the archway, and came to a stand-still in
a quiet corner of the paved playground.

"Well," asked Diggory, "who did it?"

"Who d'you think it was?" retorted Jack Vance.

"Why, some of Thurston's lot, I believe."

"So do I."

Mugford, who was always rather slow at grasping a new idea, opened his
eyes in astonishment. "But," he exclaimed, "how about the paper and the
screw-driver?"

"Pooh!" answered Diggory, "how about that cipher note that said,
'To-night'?"

"Of course," added Jack Vance, "they'd evidently arranged it beforehand,
and that paper was to say when they were to do the trick."

It seems possible sometimes to come by wrong roads to a right
conclusion; and though the boys were mistaken in changing from their
first opinion as to the meaning of the note, yet in this instance their
error caused them to hit the right nail on the head.

"It was one of Thurston's lot who did it," repeated Diggory decisively;
"neither Oaks nor Allingford would ever dream of doing such a mad
thing."

"I don't see exactly how you can prove it," said Jack Vance
thoughtfully; "that one word 'To-night' might mean anything