Originally numbering over 200, these 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 in Boston.
Based in large measure on designs laid out in Henry T. Brown's 507 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 to oscillating motion, as well as solutions to a variety of mechanical tasks. The models continue to be of interest to a range of Museum visitors, from young children to mechanical designers and tinkerers
Cornell University Library and Boston's Museum of Science are collaborating to integrate the entire Clark Collection into the Kinetic Models for Design Digital Library (KMODDL). For now a good sampling is available here.