The phenakistiscope was the first widespread animation device that created a fluent illusion of motion.
A series of pictures showing sequential phases of the animation are seen through small slots spaced evenly around the rim of a disc.
The user would spin the disc and look through the moving slits at the images reflected in a mirror, seeing a rapid succession of images that appear to be a single moving picture.
This animation shows one such phenakistiscope disc, entitled Running rats, created by Thomas Mann Baynes in 1833.