The very relationship between tones which makes it possible to join them harmonically also enables them to be connected melodically. A series of successive tones which share this relationship, that is, tones of an underlying key connected in a successive series, is called a melody.

A composition contains just as many different melodies as there are voices present. {4} Although (as we shall see) the main directions of these voices must arise in the soul of the creating composer together as one single picture to attain the proper aim of art, nevertheless these voices are not of one and the same nature, they do not have a common purpose. One of them contains, as it were, the sketch of the painting, the precise content of the ideal of the composer; this is called the principal part. Another serves him as the basis for the harmonic texture with which this picture is painted; this is called the bass voice. Others are present to contribute the drapery, the decoration, and finishing touches; these are called middle, filling, or subsidiary voices. The principal part of a composition is the one which, in the mechanical section of this treatise, I call the melody.

Remark