ve all to
be keen. I--What is that noise?"

From the other side of the door proceeded a sound like water gurgling
from a bottle, mingled with cries half-suppressed, as if somebody were
being prevented from uttering them by a hand laid over his mouth. The
sufferer appeared to have a high voice.

There was a tap at the door and Mike walked in. He was not alone.
Those near enough to see, saw that he was accompanied by Jellicoe's
clock-work rat, which moved rapidly over the floor in the direction of
the opposite wall.

"May I fetch a book from my desk, sir?" asked Mike.

"Very well--be quick, Jackson; we are busy."

Being interrupted in one of his addresses to the Brigade irritated Mr.
Downing.

The muffled cries grew more distinct.

"What--is--that--noise?" shrilled Mr. Downing.

"Noise, sir?" asked Mike, puzzled.

"I think it's something outside the window, sir," said Stone
helpfully.

"A bird, I think, sir," said Robinson.

"Don't be absurd!" snapped Mr. Downing. "It's outside the door.
Wilson!"

"Yes, sir?" said a voice "off."

"Are you making that whining noise?"

"Whining noise, sir? No, sir, I'm not making a whining noise."

"What _sort_ of noise, sir?" inquired Mike, as many Wrykynians
had asked before him. It was a question invented by Wrykyn for use in
just such a case as this.

"I do not propose," said Mr. Downing acidly, "to imitate the noise;
you can all hear it perfectly plainly. It is a curious whining noise."

"They are mowing the cricket field, sir," said the invisible Wilson.
"Perhaps that's it."

"It may be one of the desks squeaking, sir," put in Stone. "They do
sometimes."

"Or somebody's boots, sir," added Robinson.

"Silence! Wilson?"

"Yes, sir?" bellowed the unseen one.

"Don't shout at me from the corridor like that. Come in."

"Yes, sir!"

As he spoke the muffled whining changed suddenly to a series of tenor
shrieks, and the india-rubber form of Sammy bounded into the room like
an excited kangaroo.

Willing hands had by this time deflected the clockwork rat from the
wall to which it had been steering, and pointed it up the alley-way
between the two rows of desks. Mr. Downing, rising from his place, was
just in time to see Sammy with a last leap spring on his prey and
begin worrying it.

Chaos reigned.

"A rat!" shouted Robinson.

The twenty-three members of the Brigade who were not earnest instantly
dealt with the situation, each in the manner that seemed p