The problems given in Plates IV to VIII inclusive have been chosen because of their particular bearing on the work of the mechanical draftsman. They should be solved with great care, as the principles involved will be used in later work.

Penciling

The horizontal and vertical center lines and the border lines should be laid out in the same manner as in Plate I. Now measure off 2 1/4 inches on both sides of the vertical center line and through these points draw vertical lines as shown by the dot and dash lines, Plate IV. In locating the figures, place them a little above the center so that there will be room for the number of the problem.

Draw in lightly the lines of each figure with pencil and after the entire plate is completed, ink them. In penciling, all intersections must be formed with great care as the accuracy of the results depends upon it. Keep the pencil points in good order at all times and draw lines exactly through intersections.