Mikha'il Mishaqah (1800-1889) was the first theorist to propose a division of the octave into twenty-four equal tones (24-tone equal temperament, quarter tone scale), this being the current basis of the Arab tone system. (Touma 1996, p.19)

Source

• Habib Hassan Touma (1996). The Music fo the Arabs, trans. Laurie Schwartz. Portland, Oregon: Amadeus Press. ISBN 0931340888.