"Good-by." He held her hand a moment longer, and then turned suddenly away. She watched until he was out of sight, and then slipped up-stairs, undressed in the dark and crept in between the covers. Lark apparently was sound asleep. Carol giggled softly to herself a few times, and Lark opened one eye, asking, "What's amatter?"

"Oh, such a good joke on p'fessor," whispered Carol, squeezing her twin with rapture. "He doesn't know it yet, but he'll be so disgusted with himself when he finds it out."

"What in the world is it?" Lark was more coherent now.

"I can't tell, Lark, but it's a dandy. My, he'll feel cheap when he finds out."

"Maybe he won't find it out."

"Oh, yes, he will," was the confident answer, "I'll see that he does." She began laughing again.

"What is it?"

"I can't tell you, but you'll certainly scream if you ever do know it."

"You can't tell me?" Lark was wide awake, and quite aghast.

"No, I can't, I truly can't."