Harmonium by Jacob Alexandre, Paris, 19th century—Behr Photography
Free-reed keyboard instrument in which wind from a foot-operated bellows causes metal reeds to vibrate. Pitch is determined by the size of the reed; there are no pipes. Separate sets of reed produce different tone colours, the sound quality being determined by the size and shape of the tone chamber surrounding each reed. The harmonium developed in the early to mid-19th century in Europe and America, and it was a very popular church and home instrument into the 1930s.