Nurse insisted on sending Erica to bed at once, with hot blankets and bottles, but the two seniors protested that they felt none the worse for their adventure, for they had been given hot baths and had their clothes thoroughly dried at Frattenton. Indeed, they looked none the worse. Nurse gave in, on the condition that they went to bed early in the evening and had a "proper night's rest." The two received a summons from the Principal to tea in her room. "We're honoured," said Duane to Kitty with a laugh. "It's only on very special occasions that girls have tea with Prinny." A few minutes later found them comfortably ensconced in easy chairs before a bright fire, in the Principal's charming little sitting-room, with cups of tea in their hands and plates of the same delicate and fragile china on their knees. The Principal talked to them pleasantly while they had tea, and Kitty thought what a charming woman she was; though, to be sure, nothing out of the ordinary to look at! Then, after the maid had cleared the tea-things away, she drew a chair up next to Duane's and said with a sudden change to gravity: "And now, Duane, for a very serious little talk. I want to know exactly what happened in this distressing affair of the Richoter examination. I know, of course, that there has been a good deal of trouble in the school over it and that you have been very much concerned in it. I want to hear your version of the affair--all you know about it." Duane hesitated, looking perplexed. Miss St. Leger, who was watching her closely, went on quietly: "Need I say that I already know almost all there is to know? The cycling expedition and its sequel have at last brought things to a head, I am thankful to say. I insisted on an explanation from Bertha, and under the circumstances she could do nothing but give me it: I have seen the note for her which Erica left behind. But I want your version of the story as well--all of it." Duane drew a deep breath. "I was hoping that it would never come out," she said with a faint smile, "and yet of course, now it has--well, I do feel relieved." "Yes, I can quite realize that," said Miss St. Leger, somewhat dryly. "You know who did it, then?" queried Duane. Kitty was sitting forward in her chair, tense with eagerness. The mystery that had puzzled her and the rest of the school for so long, was to be revealed at last. "Yes, little Erica Salter was the culprit." Kitty uttered a cry of surprise. "Erica Salter--that child!" Duane nodded. "Yes." "But surely--" stammered Kitty, "she could not think of such a thing herself. Why, what does a child like her know of chemistry experiments?" "That is one of the little points I want Duane to make clear," put in Miss St. Leger. "Yes, Kitty can stay and hear, since I believe she also narrowly escaped serious trouble over the affair."