PERCUSSION INSTRUMENT

any musical instrument, among the oldest known, that may be classified in one of two main categories: idiophones, which emit sound when their own substance vibrates (as with bells, cymbals, and castanets), and membranophones, which emit sound when an attached, stretched membrane vibrates (as with drums). Each group contains instruments of both definite and indefinite pitch; timpani, bells, and xylophones are tuned to definite pitches, whereas snare drums, triangles, clappers, rattles, and cymbals are of indefinite pitch. Both types serve chiefly to delineate rhythm, though the tunable instruments may also be used for melody. The term percussion instrument refers to the fact that most idiophones and membranophones are sounded by being struck, but other playing methods include rubbing, shaking, plucking, and scraping. any musical instrument belonging to either of two groups, idiophones or membranophones. Idiophones are instruments whose own substance vibrates to produce sound (as opposed to the strings of a guitar or the air column of a flute); examples include bells, clappers, and rattles. Membranophones emit sound by the vibration of a stretched membrane; the prime examples are drums. The term percussion instrument refers to the fact that most idiophones and membranophones are sounded by being struck, although other playing methods include rubbing, shaking, plucking, and scraping. Although many idiophones and some membranophones are tunable and hence may be melody instruments, both groups serve typically to delineate or emphasize rhythm. Percussion instruments form the third section of the modern Western orchestra, stringed and wind instruments making up the other two sections. The term percussion instruments dates to 1619, when Michael Praetorius wrote of percussa, klopfende Instrument (German klopfen, "to beat") as any struck instrument, including struck chordophones (stringed instruments). The same combination, including pre-bow chordophones, constituted the divisio rhythmica in the 7th-century Etymologiae of Isidore, archbishop of Seville. Additional reading James Blades, Percussion Instruments and Their History, rev. ed. (1984), is a definitive work in the field, with numerous illustrations and bibliographies; Margaret A. Schatkin, "Idiophones of the Ancient World," Jahrbuch fr Antike und Christentum, 21:147-172 (1978), surveys uses of percussion instruments in ceremonies of major cultures of antiquity; Reginald Smith Brindle, Contemporary Percussion, 2nd ed. (1991), offers information on how composers write for these instruments; James Holland, Percussion (1978), presents the history and development of orchestral percussion. For separate groups of instruments, see Joseph H. Howard, Drums in the Americas (1967), containing descriptions of the most popular drums from pre-Columbian times to the present; Richard St. Barbe Baker, Africa Drums, rev. ed. (1951), based on anthropological material on Kenya and Nigeria; C.R. Day, The Music and Musical Instruments of Southern India and the Deccan (1891, reprinted 1974), still useful though dated; and Wendell Westcott, Bells and Their Music (1970), a brief survey of the cultural role of the bell from the Bronze Age. Good coverage of drums, membranes, and plates is provided in Neville H. Fletcher and Thomas D. Rossing, The Physics of Musical Instruments (1991). Edmund Addison Bowles