Construction Of A Divided Angle
An illustration showing the construction used to divide an angle into two equal parts. "With C as a center, draw the dotted arc DE; with D and E as centers, draw the cross arcs at F with equal radii. Join CF, which divides the angle into the required parts."
Albert A. Hopkins Scientific America: Handy Book Of Facts And Formulas (New York: Munn & Co., Inc., 1918) 35
Courtesy the private collection of Roy Winkelman