freshman in the class shall know it
to-morrow!" the emissary exclaimed privately to her friend, the red
domino.

"In spite of what her brother is doing for us to-night?" returned the
red domino.

"You are quite right, child. I never thought of that. Perhaps that is
the very reason he is helping us get even to-night."

"I think it is," added the other, quietly.

"Girls, we must hurry up and begin," whispered another of the six
dominoes. "They are all going to unmask at half-past ten."

So the unrecognized intruders slipped away, stationing themselves about
the room.

Pretty soon a rumor began to spread among the dancers that there were
young men present. No one knew exactly how it started, but it grew and
spread with such persistency that it finally reached the ears of the
chaperon.

"Some of the girls saw their feet," said her informant, "and not only
their feet but their trousers, too."

The teacher rose and rapped sharply for order.

"Young ladies," she called in a loud voice, "I am sorry to disturb the
dancers, but we have every reason to believe there are some men in the
room. Since it is not yet time for you to unmask, it will be simple to
find out who does not belong here by having you file past me. I will
lift each mask myself."

The dancers accordingly arranged themselves in a long line and walked
single file past the teacher. She saw only girl's faces, however, as she
peeped under the masks, and the dance proceeded.

The next disturbance came when the maskers had all taken their stand at
one end of the room at the request of the six dominoes, who managed to
whisper to each sophomore that there was presently to be a surprise.

An expectant hush fell over the company as the six dominoes filed out of
a side room and stood, for a moment, in full view of the sophomores.
Then the six deliberately lifted their dominoes, disclosing trouser legs
and men's shoes. Instantly the place was in pandemonium; yet before the
sophomores could rush upon the intruders six long horns were blown in
unison, and immediately the lights went out. In the darkness the six
dominoes made for the stairs, rushed along the gallery, and were
admitted to the laboratory by the duplicate key. But, just before the
blue domino disappeared, she called out in a loud voice from the
gallery:

"The freshmen are avenged!"

When the doors were safely closed the lights were turned on again,
disclosing the sophomores blinking foolishly at