the scale of 12 semitones. The chromatic scale is regarded as a major or minor scale of passing semitones; hence the rules governing its notation: all diatonic degrees must be notated without enharmonic substitutions. In the major mode, diatonic degrees are indicated in ascending by augmenting the notes of the diatonic scale, except that a diminished seventh is used instead of an augmented sixth. In descending, the notes of the diatonic scale are diminished, except that an augmented fourth is used instead of a diminished fifth. In the minor mode, the notation of the relative major is used in ascending, and that of the major of the same name is used in descending.