In his tribus generibus dissimiles sunt tetrachordorum dispositiones, quod harmonia tetrachordorum et tonos et dihesis habet binas (dihesis autem est toni pars quarta; ita in hemitonio duae diheses sunt conlocatae);  chromati duo hemitonia in ordine sunt composita, tertium trium hemitoniorum est intervallum;  diatono toni duo sunt continuati, tertium hemitonium finit tetrachordi magnitudinem.
In these three scales, the arrangements of the tetrachords differ. The harmonic scale has two tones in the tetrachord and two quarter-tones. (Now two quarter-tones make a semitone.) The chromatic tetrachord has two consecutive semitones and the third interval is of three semitones. The diatonic tetrachord has two consecutive tones, and the third interval'a semitone'completes the amount of the tetrachord.
final_alignments\Vitruvius_Architecture_Book_5.json