[NEW! Version with audio is here:    • Mechanical Movements — Rotary Motion,...   ] The Clark Collection of Mechanical Movements, housed at the Museum of Science (MoS) in Boston, is a set of working models of mechanical movements and combinations of drive mechanisms built by American engineer William M. Clark in the early 1900s. Originally numbering over 200, these working models were displayed as the Mechanical Wonderland in New York in 1928 and at the Century of Progress Exhibition in Chicago in 1933. Today, 120 of these mechanical models remain in working order and on display at the Museum. Based in large measure on designs laid out in Henry T. Brown's "Five Hundred and Seven Mechanical Movements" (1871), the Clark models include gear mechanisms, pulley systems, cutaways, and cross sections of a variety of machines. They illustrate methods of converting rotary to rectilinear motion and rectilinear into oscillating motion, and solutions to a variety of other mechanical tasks. Clark published photographs and descriptions of these models in 1933 in his "Manual of Mechanical Movements."