A Bunch of Cherries by L.T. Meade

At the beginning of the autumn term there happened to come to the school a girl of the name of Bertha Keys. She was between seventeen and eighteen years of age, and came to Cherry Court School in the capacity of pupil teacher. She was not a pleasant girl to look at, and had Mrs. Clavering seen her before she engaged her she might have hesitated to bring her into the midst of her young scholars.

But Bertha was clever and outwardly amiable. She performed her duties with exactitude and despatch. She kept the younger girls in order, and was apparently very unselfish and willing to oblige, and Mrs. Clavering, after the first week or fortnight, ceased to feel apprehensive when she looked at her face. For Bertha's face bore the impress of a somewhat crooked mind. The small light blue eyes had a sly gleam in them; they were incapable of looking one straight in the face. Bertha had the fair complexion which often accompanies a certain shade of red hair, and but for the expression in her eyes she might have been a fairly good-looking girl. She had an upright trim figure, and dressed herself neatly. Those watchful eyes, however, marred the entire face. They were as clever as they were sharp and knowing. Nothing escaped her mental vision. She could read character like a book.