Notes: "These are basic proportional dividers by Dietzgen, with only the lines and circles scales. The Lines scale is for dividing a line into a given number of equal length parts, and for setting the points at fixed ratios: 1 to 5, 1 to 6, etc. The Circles scale is for dividing the circumference of a circle into a given number of equal length segments. Set the slider to the number of segments you want, spread the long points to the diameter of the circle, then mark off the segments with the small points. "