The zoetrope is a mechanical optical device invented in 1834 by William George Horner, a British mathematician. It became a popular Victorian parlor toy until it was replaced by modern film technology.
Before the Zoetrope
Horner originally called the device a daedalum, which means "wheel of the devil." It was similar to the earlier phenakistoscope (invented by Joseph Plateau in 1831), but did not require mirrors. Unlike the phenakistoscope, the daedalum could be viewed by more than one person.
How the Zoetrope Works
The zoetrope looks like a drum with an open top on a centered axis. A strip of hand-drawn pictures is attached to the bottom of the inside. When the drum is spun on its axis, the viewer looks in through slots on the side, and the pictures seem to move. Looking at the pictures through the slots keeps the images from blurring together. The faster the drum is spun, the smoother the "movie" appears.
Persistence of Motion
The zoetrope is the third optical toy, after the thaumatrope and the phenakistoscope, to use the principle of persistence of vision to create the illusion of motion. The slightly-changing pictures inside the zoetrope fool the eye into thinking that the minute changes are actually the object moving.
Zoetrope Becomes Obsolete
The zoetrope lost popularity when the praxinoscope was invented by Emile Reynaud in 1877. The praxinoscope's picture was clearer and brighter than the zoetrope's.