The Thaumatrope is a early nineteenth century philosophical toy in which two images, viewed in quick succession, blend together. The images are on either side of a piece of card spun rapidly along its middling by two twisted cords. In the two examples below, the bouquet of roses appears to be in the vase, and the dog appears to be barking at the birds. The name comes from Greek words meaning "wonder" and "to turn". The device was invented by the English physician John Ayerton Paris (1785-1856), who described it in 1825 and included it in his 1827 Philosophy in Sport Made Science in Earnest.
These optical recreations are in the Wileman Collection
at the North Carolina School of Science and Mathematics in Durham.
REF: Thomas B. Greenslade, Jr., "Nineteenth Century Textbook Illustrations LII: Stroboscopic Effects", Phys. Teach., 30, 123-125 (1992)