[Meaning] the string being well and skilfully [positioned] in the melodies of songs.[1]
Harmony follows upon things which are fitted together [h(rmosme/nois], for it is necessary that there be strings, and then that they be stretched in such a way, and thus harmony ensue. [Harmony] does not fight with things that are fitted together, but holding thus it follows so that it might hold the things which are fitted together.[2] Harmony is a sounding-together [sumphonia] of the strings. Discord [anarmostia] is the sickness and weakness and ugliness of a living body, of which the sickness is the asymmetry of the elements, the weakness [is the asymmetry] of the more similar [parts], and the ugliness [is the asymmetry] of the organs.[3] Harmony is an order or composition of things which have been combined. It is spoken of in two ways. According to the one meaning [it is] the composition of bodies, whenever it is set up in such a way that it is not able to be infused with another thing, whether a rock or some one of the related heavy bodies. And from these things we transfer the word "harmony" to the ratio of combined things, such as in mixtures or in things concerning music. For we say that the ratio of combined things is one and one half to one, or one and a third to one, or some other [fraction] of the composites according to the metaphor of harmony. According to the other meaning,[4] harmony is said for juxtaposition, since these things are more familiar to us. Neither composition nor well-ordered admixture, then, create the soul.[5] So it is necessary [to use this word] for the efficient causes and the sort of substance, that is to say, its property. For bronze resonates in one way and iron in another and lead in another, and wood [in another]. Therefore "harmonicas"[6] are accustomed to be furnished from different substance[s], so that they might perfect harmony by the difference of their resonances. For harmony of very mixed things is the union of people with divergent opinions. Therefore [it is] impossible for a sound to happen when there is only one [entity].[7]
Harmonies are also said [to be] the nailed-together parts of furniture. "With the harmonies gaping." But these [are] figurative expressions. Aristophanes [sc. writes this].[8]