Do not, however, encourage the pupil to depend on or permit himself to be crippled by the constant application of mechanical methods or appliances, or allow the use thereof to interfere with free-hand drawing. They are intended for occasional use. To avoid this, have him frequently lay aside the guide line methods and trust more to the eye.
Whenever desirable more divisions can easily be made. The additional spaces need not be made over the entire sur-
face, but the surface may be subdivided indefinitely in whole or in part, according to the intricacy of detail in the design to be copied, same size, enlarged or reduced.

General Directions for Triangular Guide Lines
Triangular guide lines are particularly adapted for the purpose of enlarging or reducing portraits.
In this exercise a small pencil sketch of the Father of His Country is offered as an example, showing the start of an enlarged drawing of the sketch.
The guide lines should be made as faintly as possible.
After the main outlines of the features and forms of the principal shadows are indicated with lines considerably stronger than the guide lines, the whole drawing may be rubbed over with dry bread crumbs. By this means the guide lines will be nearly, if not quite, obliterated, while the outlines of the features and shadows will remain sufficiently visible as a means by which to finish the drawing.
