On the Institution of Music (De institutione musica)

On the Kinds of Song, Chapter 21.

Having explained these matters, we must now speak of the kinds of melodies. There are three: the Diatonic, the Chromatic, and the Enharmonic. The Diatonic is somewhat harder and more natural; the Chromatic, however, departs from that natural tension and falls into a softer sound. The Enharmonic is very well and fittingly joined. Since there are five tetrachords a scale of four notes spanning the interval of a fourth—the hypaton the "lowest" or principal notes, the meson the middle notes, the synemmenon the "conjunct" or connected notes, the diezeugmenon the "disjunct" or separated notes, and the hyperboleon the "highest" or supreme notes—in all of these, according to the Diatonic genus, the voice produces song through a semitone, a tone, and a tone in one tetrachord, and then in another through a semitone, a tone, and a tone, and so on. Therefore, it is called "Diatonic," as if it proceeds "through tones" original: "diatoni quasi quod per tonum ac tonum progrediatur".

The Chromatic, which is named for "color" original: "Chroma quod dicitur color", is like a first alteration from this natural tension; it is sung through a semitone, another semitone, and three semitones an interval equal to a minor third. For the whole diatessaron original: "diatesseron"; the interval of a perfect fourth consonance consists of two tones and one semitone (though not a full one). This name "Chroma" is derived from the way surfaces change their appearance when they pass into another color.

The Enharmonic, however, is that which is most closely fitted together. In all tetrachords, it consists

of a diesis, another diesis, and a ditone a "double tone" or major third. A diesis is half of a semitone effectively a quarter-tone, so that the description of the three genera running through all the tetrachords may be seen here in this manner.

On the Order of the Strings and Their Names in the Three Genera, Chapter 22.

Now, therefore, we must arrange the order of all the strings, which vary across these many genera. They are arranged in a constant order. The first is the proslambanomenos original: "proslabanomenos"; the "added note" at the bottom of the scale, which is also called the prosmelos. The second is the hypate hypaton the lowest of the lowest tetrachord; the third is the parhypate hypaton the note next to the lowest.

The fourth is universally called the lichanos the "index finger" string, but if it is fitted arranged to the Diatonic genus, it is called the "Diatonic lichanos hypaton." If, however, it is in the Chromatic, it is called lichanos the "Chromatic lichanos hypaton." If it is in the Enharmonic, it is called the "Enharmonic lichanos hypaton."

After this is called the hypate meson lowest of the middle tetrachord; then the parhypate meson. From there, the lichanos is called the "Diatonic meson" (simply in the Diatonic genus), or the "Chromatic meson" in the Chromatic. In the Enharmonic, it is the "Enharmonic Diatonic meson" or "Enharmonic lichanos meson." These are followed by the mese the "middle" note, the center of the Greek tonal system. After this, there are two tetrachords, partly...

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