This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
In drawing the straight line exercises points should first be placed lightly and the line drawn to connect themas in Fig. 1. Draw a series of ten or fif-teen lines in each position, placing the points to be connected by the lines one inch apart and leaving a space of one quarter of an inch between each line. Next draw a series placing the points two inches apart, then a group with the points lour inches apart, and finally a set which will give lines eight inches long. Start to draw vertical lines from the top, horizontal lines from the left to right, oblique lines which slant upward toward the right, from the lower point, and those slanting upward toward the left, from the upper point. Use all three pencils. 3H, F and a solid ink pencil for these exercises, and take the greatest care not to press too strongly on the paper with the harder grades. They are intended to make rather light gray lines. Where dark lines are desired always use the solid ink pencil. Try also making the exercises with different widths of line regulated by the bluntness of the point, and do at least one set using the solid ink pencil and making very wide lines as near together as is possible without fusing one line with another. In all of these exercises the lines should each he drawn with one pencil stroke without lifting the pencil from the paper and absolutely no corrections of the line should be made.
Fig. 1. Lines, Connecting Points.