Kinematic curve models

These gear models served to teach the principles of kinematics, or the science of movement. Germany's J. Schröder built them for the Darmstadt Polytechnisches Arbeits Institut to demonstrate the steady transmission of a movement with variable speed. Schröder, known for the quality of his models, won awards at the 1844 and 1854 national exhibitions in Berlin. At the 1862 Universal Exhibition in London, the Conservatoire des arts et métiers commissioned him to make several curve models shaped like hearts, Maltese crosses and four-pointed stars to illustrate the laws of mechanics.