Photo showing an exhibition of French scientific instruments

Photograph with a caption that reads: '144902. "Kepes" Ephimeter. For measuring Young's Modulus and the modulus of internal friction. The purpose of this apparatus is to enable the modulus of elasticity and the coefficient of internal friction to be measured simultaneously. The test-piece is a circular cylinder. Its base being fixed in a rotating vertical shaft, it is acted upon at its upper end by a horizontal forces, the direction of which is fixed. As a result of the consequent rotary flexion every part of the test-piece is subjected to a sinusoidal tension and compression the frequency of which is equal to the number of revolutions per second performed by the rotating shaft. (Etaakissements Saintgobain).'