Two display mechanisms, possibly constructed by Science Museum workshops, designed to rotate original or replica Thaumatrope discs in order to view the optical illusion of combining the two images on either side of each disc as one. A drive cable was probably attached to the pulley on the shaft at one end, and a turning handle at the other, in order to rotate the shaft. Display Mechanism for Rotating a Thaumatrope Disc c. 1925