so that at different times all the pupils may get very clearly the idea of light and dark colors in the same scale.
This idea can be more clearly shown by means of a simple model very easily made for the purpose. Take, for example, three pieces of standard red paper, 4×4 inches, and mount them on a piece of cardboard side by side, in a row. Trim the card parallel to the edges of the papers, leaving a margin of uniform width, and with the point of a knife "score" a line partially through the card from the front, at the joining of the papers, so that it can be neatly bent to the form shown in
Fig. 16.
Fig. 16 which represents the model as seen by the class. By holding one of the rear edges with each hand the faces can be folded to different angles with each other and the model turned to different positions with relation to the children. Possibly the windows at the rear of the room may be partially darkened to advantage; they certainly can be if they have a sunny exposure at the time. The object is to give a fair daylight on the central surface for the standard, a strong light on one side to form a tint of the standard and a shadow on the other for a shade of the same color.
By a trial before school, in company with some other teacher perhaps, the best positions for different parts of the room as well as best lighting of the room may be determined in advance and thus such a success achieved with the first experiment that the whole idea of tint and shade may be impressed on each child for all time and definitions firmly fixed in his mind for these two most abused words in our every day vocabulary.
