ing about the big snowball that just
came hurtling down these stairs?" stormed Professor Duke.

"No, sir. I just reached the top of the stairs," answered Brassy Bangs.
"I came out of my room not ten seconds ago."

"What do you know about this, Stowell?" went on the professor, who had
now come slowly to the top of the stairs, followed by Professor Grawson,
who had come out of Colonel Colby's private office where he had been
looking over some reports when the big snowball had landed with a thump
against the desk at which he had been seated.

"Me? What do you mean?" stammered the youth who was known to the cadets
as Codfish and who had always been more or less of a sneak.

"Somebody just rolled a big snowball down the stairs. It struck me and
nearly knocked me flat," returned the irate teacher.

"Yes, and it rolled all the way into the private office," added Professor
Grawson.

"I don't know anything about any snowballs," said Codfish. "I noticed the
floor was all wet and I wondered what it meant."

"I saw some fellows rushing around the corner," came from Brassy Bangs.

"Who were they?" demanded Snopper Duke.

"I don't know."

"Which way did they go?"

"That way," and Brassy pointed out the direction.

By this time the two professors had reached the top of the stairs and
Grawson was looking at the water marks on the polished floor.

"Here is where they brought that big snowball in," he remarked, pointing
to the track that led to one of the windows. "They must have brought it
up on the fire-escape."

"Here are several other tracks. I think we had better follow them,"
returned Snopper Duke quickly.

The track leading to the bathroom was most in evidence, and the two
professors quickly discovered the big snowball resting in the bathtub.

"Evidently they put this here to have some more fun with," announced
Professor Grawson grimly. "Well, it won't do much harm here. I'll turn on
a little hot water and it will soon melt and run off," and he turned on
the faucet as he spoke.

From the bathroom the two professors, followed by Codfish and Brassy,
followed the water trail into a room occupied by several students who
were particularly uppish and whom the Rovers did not like, and here some
more of the snowballs were found.

"Here is another trail," announced Professor Duke, and in a moment more
had thrown open the door leading to Stowell's bedroom.

"Here! what does this mean?" stammered Codfish, as, after the