In the discussions to which we have been referring, Aristoxenus invariably employs the word [Greek: tonos] in the sense of 'key.' The word [Greek: harmonia] in his writings is equivalent to 'Enharmonic genus' ([Greek: genos enarmonion]), the _genus_ of music which made use of the Enharmonic _diësis_ or quarter-tone. Thus he never speaks, as Plato and Aristotle do, of the Dorian (or Phrygian or Lydian) [Greek: harmonia], but only of the [Greek: tonoi] so named. There is indeed one passage in which certain octave scales are said by Aristoxenus to have been called [Greek: harmoniai]: but this, as will be shown, is a use which is to be otherwise explained (see p. 54). § 12. _Plutarch's Dialogue on Music._ After the time of Aristoxenus the technical writers on music make little or no use of the term [Greek: harmonia]. Their word for 'key' is [Greek: tonos]; and the octachord scales which are distinguished by the succession of their intervals are called 'species of the octave' ([Greek: eidê tou dia] [Greek: pasôn]). The modes of the classical period, however, were still objects of antiquarian and philosophic interest, and authors who treated them from this point of view naturally kept up the old designation. A good specimen of the writings of this class has survived in the _dialogus de musicâ_ of Plutarch. Like most productions of the time, it is mainly a compilation from earlier works now lost. Much of it comes from Aristoxenus, and there is therefore a special fitness in dealing with it in this place, by way of supplement to the arguments drawn directly from the Aristoxenean _Harmonics_. The following are the chief passages bearing on the subject of our enquiry: (1) In cc. 15-17 we find a commentary of some interest on the Platonic treatment of the modes. Plutarch is dwelling on the superiority of the older and simpler music, and appeals to the opinion of Plato. 'The Lydian mode ([Greek: harmonia]) Plato objects to because it is high ([Greek: oxeia]) and suited to lamentation. Indeed it is said to have been originally devised for that purpose: for Aristoxenus tells us, in his first book on Music, that Olympus first employed the Lydian mode on the flute in a dirge ([Greek: epikêdeion aulêsai Lydisti]) over the Python. But some say that Melanippides began this kind of music. And Pindar in his paeans says that the Lydian mode ([Greek: harmonia]) was first brought in by Anthippus in an ode on the marriage of Niobe. But others say that Torrhebus first used that mode, as Dionysius the Iambus relates.'