of Argos (fl. 590 B.C.). 'There being three keys (tonoi) in the time of Polymnastus and Sacadas, viz. the Dorian, Phrygian and Lydian, it is said that Sacadas composed a strophe in each of these keys, and taught the chorus to sing them, the first in the Dorian, the second in the Phrygian, and the third in the Lydian key: and this composition was called the "three-part Nome" (nomos trimerês) on account of the change of key.' In Westphal's Harmonik und Melopöie (ed. 1863, p. 76, cp. p. 62) he explains this notice of the ancient modes (harmoniai, Tonarten), observing that the word tonos is there used improperly for what the technical writers call eidos tou dia pasôn.

(3) In a somewhat similar passage of the same work (c. 19) Plutarch is contending that the fewness of the notes in the scales used by the early musicians did not arise from ignorance, but was characteristic of their art, and necessary to its peculiar ethos. Among other points he notices that the tetrachord Hypatôn was not used in Dorian music (en tois Dôriois), and this, he says, was not because they did not know of that tetrachord—for they used it in other keys (tonoi)—but they left it out in the Dorian key for the sake of preserving its ethos, the beauty of which they valued (dia dê tên tou êthous phylakên aphêroun tou Dôriou tonou, timôntes to kalon autou). Here again Westphal (Aristoxenus, p. 476) has to take tonos to mean harmonia or 'mode' (in his language Tonart, not Transpositionsscala). For in the view of those who distinguish harmonia from tonos it is the harmonia upon which the ethos of music depends. Plutarch himself had just been saying (in c. 17) that Plato preferred the Dorian harmonia on account of its grave and elevated character (epei poly to semnon estin en tê Dôristi, tautên proutimêsen). On the other hand the usual sense of tonos is supported by the consideration that the want of the tetrachord Hypatôn would affect the pitch of the scale rather than the succession of its intervals.

It seems to follow from a comparison of these three passages that Plutarch was not aware of any difference of meaning between the words tonos and harmonia, or any distinction in the scales of Greek music such as has been supposed to be conveyed by these words. Another synonym of tonos which becomes very common in the later writers on music is the word tropos. [6] In the course of the passage of Plutarch already referred to (De Mus. c. 17) it is applied to the Dorian mode, which Plutarch has just called harmonia. As tropos is always used in the later writers of the keys (tonoi) of Aristoxenus, this may be added to the places in which harmonia has the same meaning.