"A very jinky notion. We might get an idea on the spot."

The four prefects slept in the Violet Room at the end of the passage. They were allowed to sit up later than the rest of the school, and at this moment were downstairs finishing some preparation. It was an easy matter, therefore, to visit their quarters. Laura, Irma, Janet, Ethelberga, and Avelyn made a dash down the passage, turned up the gas, and began an inspection. The Violet Room was quite the prettiest of the dormitories; it was also the largest, and had a round table and four easy chairs with comfortable cushions. The table was spread with a white cloth, on which were set forth four cups and saucers, a tin of cocoa, a small basin of sugar, and a plate of biscuits. The prefects were working overtime for an examination, and were allowed this special indulgence to refresh their tired brains before they went to bed. They boiled a tin kettle on a gas ring, and brought it upstairs with them. They considered their nightly cocoa party one of their greatest privileges.

"Looks jolly comfortable!" sniffed Avelyn, regarding the preparations with envy.

"It's well to be a prefect!" agreed Janet.

"Shall we eat the biscuits?" suggested Irma.

"Certainly not!" replied Ethelberga.

Laura had taken up the cocoa tin, and was plunged in thought.

"I've got it!" she announced suddenly. "I don't mean the tin, but an idea. Wait half a second for me!"

She dashed back to the Cowslip Room, and was away several minutes. When she returned, her face beamed triumph.

"They won't enjoy their cocoa to-night!" she chuckled. "I've mixed two teaspoonfuls of Gregory's powder with it! It will be a nice little surprise for them, won't it?"