Periodic Center of Motion Small 320×319 Medium 640×637 Large 1024×1019 Download Tiff Original 2400×2389 | (342.0 KB) Description Illustration showing the periodic center of motion as it often happens when two positions of a line are known and they are moving in the same plane and we wish to find an axis about which this line could revolve to occupy the two given positions. Keywords motion, motions, plane, rolling surface, surfaces, Translation Galleries Analytical Geometry Source: Peter Schwamb, S.B. And Allyne L. Merrill, S.B. Elements of Mechanism (New York, NY: John Wiley & Sons, Inc., 1904)