Music box is an instrument that plays tunes automatically. Steel pins protrude from a rotating cylinder driven by clockwork or a spring. The pins pluck metal teeth of various lengths, producing soft, high-pitched sounds of great delicacy. Several teeth may be tuned to the same note, so the box can repeat notes rapidly. Music boxes may be connected with clocks and play certain tunes on the hour. Music-box movements are built into watches, toys, and other everyday objects.
Early music boxes had tiny flute pipes instead of teeth and gave an organlike sound. Joseph Haydn wrote many charming pieces for the instrument. In the 1800’s, some inventors developed music boxes that had as many as 400 teeth.