"'Has someone been interfering with your balances, Constance?'
asked the Principal."
"It—it seems so, Miss St. Leger," stammered Salome. "I tested my balances to see if they were correct before weighing, and was astonished to find one side much heavier than the other. Then I took off the pans to try and find the cause and discovered this piece of gravel underneath one of them."
The faces of the Principal and the science mistress were very grave, for it looked as if a deliberate attempt had been made to spoil Salome's results. Aware that the other girls in the room had paused in their work to listen in astonishment, Miss St. Leger said decidedly, "Continue your work, girls. Constance, I will inquire into this as soon as you have all finished your practical work. Go on now with your experiment."
The Principal stayed in the room till the time allotted for the practical work was over, then she called them all together round the bench where Salome, Eileen and Duane had been working and explained to them exactly what had happened. They looked at one another with mingled feelings of discomfort and amazement.
Miss St. Leger first questioned Salome. "When did you use your balances last—I mean before your discovery at the beginning of the afternoon?"
"This morning," replied Salome at once. "Not long before we left. We had to weigh our compounds before putting them into the midget furnaces to heat during the dinner hour."
"You are sure they were correct then?"
"Quite sure, Miss St. Leger. I always lift them before using, to test and correct them, if necessary. I distinctly remember testing them this morning."
"Then that means that someone has tampered with them between then and when we returned," interposed Miss Vacher.