A thaumatrope is an optical toy that was popular in the 19th century. A disk with
a picture on each side is attached to two pieces of string. When the strings are
twirled quickly between the fingers the two pictures appear to blend into one due
to the persistence of vision.
Examples of common thaumatrope pictures include a bare tree on one side of the disk,
and its leaves on the other, or a bird on one side and a cage on the other. Many
classic thaumatropes also included riddles or short poems, with one line on each
Thaumatropes can provide an illusion of motion with the two sides of the disc each
depicting a different phase of the motion, but no examples are known to have been
produced until long after the introduction of the first widespread animation device:
Thaumatropes are often seen as important antecedents of motion pictures and in particular
of animation. This is partly due to many film historians' belief that the associated
theory of persistence of vision explains the physiological basis for movies, although
this was disproved in 1912.
The invention of the thaumatrope is usually credited to British physician John Ayrton
Paris. Paris was said to have used one to demonstrate persistence of vision to the
Royal College of Physicians in London in 1824. He described the
device in his 1827 educational book for children Philosophy in Sport Made Science
in Earnest, with an illustration by George Cruikshank.