The Music and Musical Instruments of Southern India and the Deccan c5.21

c5.21

⁶ Organum was the name given to this rude harmony. An instrument called Organistrum, in use in the ninth century, enabled these chords to be played in succession. And the organ itself appears to have been so constructed, the origin in fact of the modern mixture stops.—See Gerbert, "De cantu et musicâ sacra," St. Blaise, 1774.