scale (from It. scala, ‘staircase’, ‘ladder'; Ger. Tonleiter; Fr. gamme). A series of single notes progressing up or down stepwise. Thus, a series of notes within an octave used as the basis of comp. Scales are arbitrary, and the no. in use throughout the world is incalculable.

For the older European scales, used in the Church's plainsong and in folk song, see modes. Two of these ancient modes remained in use by composers, when the other 10 were almost abandoned, and these are our major and minor scales—the latter, however, subject to some variations in its 6th and 7th notes. Taking C as the keynote these scales (which have provided the chief material of music from about AD 1600 to 1900) run as follows:

The major and minor scales are spoken of as DIATONIC SCALES, as distinct from a scale using nothing but semitones, which is the CHROMATIC SCALE, for which 2 different notations are employed:

This scale when begun on other notes is ‘harmonically’ notated according to the same principles; for instance, beginning on D it reads:

A scale comprising the same notes as the chromatic scale is the DODECAPHONIC SCALE, in which the 12 notes are considered to be all of equal status and are so treated, whereas the chromatic scale beginning on any particular note is considered to comprise the diatonic scale of that note ‘coloured’ (this is the literal meaning of ‘chromatic’) by the addition of the extra semitones.

Scales with smaller intervals than the semitone have been introduced. See microtone.

The WHOLE-TONE SCALE is free of semitones and thus allows of only 2 different series, each with 6 notes:

An extremely widespread scale is the 5-note or PENTATONIC SCALE (common in Scottish, Chinese, and other music):

The Scottish Highland Bagpipe is tuned to a scale that cannot be represented in orthodox notation. It is roughly that of the white notes of the piano with the C and F about a quarter of a tone sharp.