ABSTRACT
T he preceding chapters exhibit the origin and nature of our diatonic scale, so far as the succession of its intervals is concerned; but this is not sufficient, for we have yet to notice a peculiar feature which is essential to its modern application. W e do not use the series of sounds indis criminately, but treat them in a certain form of combina tion. We select one of the seven notes of which the diatonic scale is composed (for the entire series, whatever its extent, may be assumed to consist only of octave replicates of seven sounds), and we invest this note with a special significance, making all the other six subservient to it, under mutual relations, which are of much import ance in the structure of modern music. This selected note is called the key-note or tonic, and the system of rela tions that hangs upon it is called tonality.
