Hughes
The twelve keys meeting by fifths, one series modulating through seven octaves, keys not mingled
—The twelve veering round, the intermediate notes not coloured
—The keys of A and E meeting the intermediate notes coloured in musical clef, . . . . . 39 [Harmonies of Tones and Colours, Table of Contents3 - Harmonies]

THE twelve keys have been traced following each other seven times through seven octaves, the keys mingled, the thirteenth note being the octave, and becoming first of each rising twelve. Thus developing, the seven notes of each eighth key were complementary pairs, with the seven notes of each eighth key below, and one series of the twelve keys may be traced, all meeting in succession, not mingled. When the notes not required for each of the twelve thus meeting are kept under, the eighths of the twelve all meet by fifths, and as before, in succession, each key increases by one sharp, the keys with flats following, each decreasing by one flat; after this, the octave of the first C would follow and begin a higher series. It is most interesting to trace the fourths, no longer isolated, but meeting each other, having risen through the progression of the keys to higher harmonies. In the seven of C, B is the isolated fourth, meeting F#, the isolated fourth in the key of G, and so on. Each ascending key-note becomes the root of the fifth key-note higher; thus C becomes the root of G, &c. [Harmonies of Tones and Colours, Diagram VII - The Modulating Gamut of the Twelve Keys1, page 29]

This diagram shews the modulating gamut of the 12 Minor Keys meeting by fifths; each of the 7 circles representing musical clefs of the 18 tones, as before. [Harmonies of Tones and Colours, Diagram Shews the Modulating of the 12 Minor Keys, page 41e]

See Also

eighth meeting
meeting by fifths
meeting of fifths
The twelve keys meeting by fifths
The Twelve Scales Meeting by Fifths
table of the twelve scales meeting by fifths