ABSTRACT
Victorians liked optical illusions, and resourceful mechanicians devised ingenious and often elaborate toys to entertain them. Some utilized a phenomenon known as persistence of vision, or ‘after sensation’. If a series of drawings of, say, a running animal is put inside a slotted drum and then viewed through one of the slots while the cylinder is rotated, the images merge and a solitary figure appears to be moving. The eye holds the impression of one drawing until the impression of the next drawing almost instantly replaces it. Towards the end of the century cinematography was founded on this simple phenomenon of persistence of vision.
