76. A scale (from scala, a Latin word meaning ladder; Ger. Ton-leiter) is an ascending or descending series of tones, progressing according to some definite system, and all bearing (in the case of tonality scales at least) a very intimate relation to the first tone—the key-tone or tonic. (See [p. 28], [Sec. 78]; also note 1 at bottom of[ p. 38].)
Many different kinds of scales have existed in various musical eras, the point of resemblance among them all being the fact that they have all more or less recognized the octave as the natural limit of the series. The difference among the various scales has been in the selection of intervals between the scale-tones, and, consequently, in the number of tones within the octave. Thus e.g., in our major scale the intervals between the tones are all whole-steps except two (which are half-steps), and the result is a scale of eight tones (including in this number both the key-tone and its octave): but in the so-called pentatonic scale of the Chinese and other older civilizations we find larger intervals (e.g., the step-and-a-half), and consequently a smaller number of tones within the octave. Thus in the scale upon which many of the older Scotch folk songs are based the intervals are arranged as follows:
| 1 | whole step | 2 | whole step | 3 | step-and- a-half | 4 | whole step | 5 | step-and- a-half | 6 |
The result is a scale of six tones, corresponding approximately with C—D—E—G—A—C in our modern system.
The term pentatonic is thus seen to be a misnomer since the sixth tone is necessary for the completion of the series, just as the eighth tone is essential in our diatonic scales.
The following Chinese tune (called "Jasmine") is based on the pentatonic scale.
77. In studying the theory of the scale the student should bear in mind the fact that a scale is not an arbitrary series of tones which some one has invented, and which others are required to make use of. It is rather the result of accustoming the ear to certain melodic combinations (which were originally hit upon by accident), and finally analyzing and systematizing these combinations into a certain definite order or arrangement. The application of this idea may be verified when it is recalled that most primitive peoples have invented melodies of some sort, but that only in modern times, and particularly since the development of instrumental music, have these melodies been analyzed, and the scale upon which they have been based, discovered, the inventors of the melodies being themselves wholly ignorant of the existence of such scales.