"No, the corridor was empty. In fact, the building seemed deserted."
"No doubt all the girls were in their houses waiting for the dinner bell. Are you quite sure you locked the door when you left the room?"
"Positive."
Here Miss Vacher interposed. "Yes, we found the door locked right enough when we returned in the afternoon, Miss St. Leger."
"One more question, Kitty. You took the key straight back to Duane? No other girl entered the laboratory while you had it?"
"No one, Miss St. Leger," replied Kitty, shaking her head.
Then Miss St. Leger explained to the puzzled senior what had happened, but Kitty, with absolute candour, declared firmly that she had not interfered with the balances and could offer no explanation of the matter. The other girls said exactly the same, and there the inquiry ended for the time being.
The Principal walked restlessly across the room and stared out of the window into the quad below. "One thing is certain," she remarked; "there are no ordinary means of entry into this room except through the door. Well, I shall probably call the whole school together for a public inquiry. Until then, I want you girls to understand that I do not wish the matter to go any farther. That will do, thank you, girls. I am sorry I have had to take up some of your time. Miss Vacher will take you into the Sixth Form room so that you can write out your results before tea-time."
Tea at Carslake's that day was the usual cheery meal, and if Kitty and Duane were unusually quiet and silent no one gave much heed to them. Consequently, it was quite a shock to all except Kitty and Duane when, directly tea was over, the house mistress gave the order to assemble at once in the hall.
"What on earth's up now?" exclaimed Hilary, as the little party of seniors made their way across the quad to the school building on the heels of their juniors. "Duane, do you know?"