or mouth organ
Small rectangular wind instrument consisting of free metal reeds set in slots in a small wooden frame and blown through two parallel rows of wind channels.
Successive notes of the diatonic (seven-note) scale are obtained by alternately blowing and sucking; the tongue covers channels not required. In chromatic (12-note scale) models, a finger-operated stop selects either of two sets of reeds tuned a semitone apart. The harmonica was invented in 1821 by Friedrich Buschmann (1805–64) of Berlin, who borrowed the basic principle from the Chinese sheng . It is widely used in blues as well as folk music and country music .