Note 19 — § 20. Tonality of the Greek musical scale.

The term hêgemôn or 'leading note' of the tetrachord Mesôn, here applied to the Mesê, is found in the same sense in Plutarch, De Mus. c. 11, where ho peri ton hêgemona keimenos tonos] means the disjunctive tone. Similarly Ptolemy (Harm. i. 16) speaks of the tones in a diatonic scale as being en tois hêgoumenois topois, the semitones en tois hepomenois (sc. of the tetrachord): and again of the ratio 5:4 (the major Third) as the 'leading' one of an Enharmonic tetrachord (ton epitetarton hos estin hêgoumenos tou enarmoniou genous).