96. A heart-cam. Uniform traversing motion is imparted to the horizontal bar by the rotation of the heart-shaped cam. The dotted lines show the mode of striking out the curve of the cam. The length of traverse is divided into any number of parts; and from the center a series of concentric circles are described through these points. The outside circle is then divided into double the number of these divisions, and lines drawn to the center. The curve is then drawn through the intersections of the concentric circles and the radiating lines.