"A most distressing thing to happen," Miss Sheerston said in her incisive way. "I would have staked my head that there is not a girl in my house capable of such an act."
The other three house mistresses emphatically declared that they also would have placed undisputed trust in every one of their older girls. There was no character in the school who could be pointed out as flagrantly dishonest. Of course the younger girls were out of the question; they did no science and were incapable of thinking out such a plot.
But it was of Duane and Kitty that the mistresses were thinking chiefly. "It seems as if one of them must be guilty," Miss St. Leger said reflectively, "and one of them a head prefect, too. If only Duane could have accounted for that half-hour or so alone after dinner, then she would have been above suspicion. I hate the thought of suspecting her."
"Things look decidedly black against the other girl, Kitty Despard," Miss Green pointed out. "We know she did go to the laboratory. We have only her word that she didn't touch the balance."
"And yet I am loath to suspect the girl," said Miss St. Leger ruefully. "I liked her straightforward, fearless look, and I reckon myself a pretty good judge of character. If she is guilty, then she is the cleverest hypocrite for a girl I have yet come across. How have you others found her?"
"I like her," said Miss Carslake. "She is not clever, but always bright and open, full of high spirits but quite unassuming. I thought she had been doing a good deal to help the improvement in the house."
"And a real sport on the field," added Miss Bryce, the games mistress. "I mean a sport in the best sense of the word."
"What puzzles me," said Miss Sheerston, "is the motive behind it all. There must be a motive of some sort, that is certain. Constance told me herself she didn't know a single girl in the school who disliked her or who bore her a grudge. The plasticine and gravel offer no clue. There is plenty of the former in the lower form classrooms, used by the little ones for map modelling and that sort of thing, while the path outside is covered with small gravel."
Then Miss Prince proffered a suggestion. "Do you think it is a question, not so much of personal spite but of house rivalry, which as you know is very keen, over examinations as well as over games? That idea excludes Miss Sheerston's girls, of course."
"It might be," admitted the Principal. "I have always encouraged friendly house rivalry, because it raises the standard of work and play. But I should be extremely sorry and disappointed if it has resulted in anything like this."