MELODY is the organization of successive musical sounds in respect of pitch (Gr. i.LEXcooia, a choral song, from AiXos, tune, and cphii, song). In its most primitive state it already re quires Rhythm (q.v.) ; but it can develop freely without the aid of Harmony, which removes it into a wider category. Thus a "melodic scale" is a scale that is not based on an harmonic system ; and thus we call ancient Greek music "melodic." The popular conception of melody as "tunefulness" is modern and depends on symmetries of harmony and rhythm that seldom occur in recorded music before the 17th century, and are accidental, if frequent, potentialities in older folk-music. For us a melody is the surface of a series of harmonies, and an unaccompanied melody that fails to imply clear harmonies is felt to be strange and vague (see Ex. I and 2). Harmonic rationality and symmetrical rhythm thus combine to make a tuneful melody an epitome of musical form. The historical process is from the smaller to the greater. See SONATA FORMS for the gradations between such melodic forms as that of Barbara Allen (Ex. 3) and the larger dance forms of the suite, and for the gradation between these and the true dramatic forms of the sonata. Lastly, the most narrowly melodic element, the rise and fall of pitch, is a capacity of the human voice, and in later forms is enlarged not less by the char acteristics of instruments than by rhythm, harmony and form. Thus modern melody is the musical surface of rhythm, harmony, form and instrumentation; and, if we take Wagnerian Leitmotif into account, we may as well add drama to the list. In short, melody, whether it be in an inner part or on the top, is the surface of music.
An immense number of musical resources are manifested on the melodic surface; and the following definitions and illustra tions will be found to cover a very wide ground. In fact, one of the principal dangers that beset the teaching of composition has been the notion that the logic of music can be placed in melodic relations without regard to rhythm (especially in its larger aspects of phrasing) as well as harmony.
I. A theme is a melody, not necessarily complete in itself, except when designed for a set of variations (q.v.), but recogniz able as a pregnant phrase or clause. Thus a fugue-subject is a theme, and the expositions and episodes of the sonata forms are more or less complex groups of themes.
2. A figure is the smallest fragment of a theme that can be recognized when transformed or detached from its surroundings. The grouping of figures into new melodies is the main resource of "development" or "working-out" in the sonata-forms (see Ex. 2-7) besides being the means by which fugues are carried on when the subjects and counter-subjects are not present as wholes. In 16th-century polyphony, melody consists largely of figures which are thus broken off from a canto fermo. (See CONTRA PUNTAL FORMS.) 3. A sequence is the repetition of a figure or group of chords at different levels of pitch. A real sequence repeats the initial group exactly, and therefore changes its key. Thus in the first movement of Beethoven's Waldstein sonata bars 5-8 are a step in real sequence below bars 1-4. A tonal sequence repeats the figure within the key, and modifies details accordingly, tolerat ing things that would be inadmissible in the initial group. In the first movement of the Waldstein sonata the theme, with a brilliant counterpoint above, is treated in tonal sequence 4o bars from the end. Repetition at the same pitch is not sequence. Thus, in illus tration, there are no sequences in Ex. 1, but Ex. 4, 7, 9 and io contain tonal sequences.
4. Polyphony is harmony made of melodic threads. Some classical melodies are polyphonically composite, requiring an inner melody, appearing through transparent places in the outer melody, to complete the sense. This well suits the pianoforte with its evanescent tone, but is even more frequent in music for earlier keyboard instruments, as in the keyboard works of Bach (see Ex. 4). Beethoven often divides a melody between voices in dialogue, as in bars 35-42 of the first movement of the Wald stein sonata, op. 53.