The blackboard drawing should be governed by the same spirit, the need of the hour, just as surely as the child’s work at his desk, and when the teacher realizes this fact, he will never lack a subject for illustration. For instance, in the fall the class may be studying trees, and drawing will be found indispensable.
The children are studying some tree near at hand, comparing trees to discover their points of likeness and difference, collecting pictures of trees and mounting these to illustrate their description, and with this study they are becoming more or less familiar with our common trees. If the teacher should go to the blackboard to enforce a point in regard to the general form of the tree, direction of branches or characteristic details, he will find such sketches a great help. It is the teacher who does such illustrative drawing who holds and interests his class.
Let us try a few simple applications of the practice previously suggested, using the trees as our topic for illustration.
No. 13. Draw a gray, vertical line suggesting the characteristic line of growth in the pine tree. Use the stroke given in No. 11 for the foliage. To represent the foliage in a mass, simply shorten or lengthen the stroke of the chalk, using a greater pressure here and there. With the side of the chalk represent the trunk of the tree where visible and with the point indicate branches.
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Certain laws govern blackboard work as well as object drawing on paper. A sketch of the object as a whole must be made first and the massing of the lights and shades must be done before detail is attempted. The general outline may often be sketched with charcoal and corrected when the chalk is used.
