MELODY. - It is the essence of music, its living substance, which organizes itself into discourse and within it unfolds a musical thought.
Since a horizontal alignment of sounds cannot fail to suggest harmonies, even if these remain implicit, every melody carries within itself the sonic relations inherent in its own complex of sounds (in its field). And since each of the sounds forming the melody, in the double order of succession and simultaneity, has its own duration (precise or imprecise), the melody is also necessarily rhythm. But no succession and simultaneity of sounds exists in reality independently of a vibrating body that produces those sounds: the melody is therefore also timbre. It unifies all the elements of musical discourse.
It is universally admitted that the essence of music is vocal: therefore the character of vocality is fundamental also in melody (one should remember, however, that vocal does not coincide with cantabile, in the current sense of easy and evident linear symmetry).
The principal forms of melody are the following.
1) Strophic form. - The strophic forms of versified poetry determine (though not always) analogous strophic structures in the music associated with them. Such strophicity of music reaches its most elementary symmetrical order in the "square" melody, in which the first 2 phrases, of 2 measures each, form the first half-phrase, which, joining with the following one of equal breadth, forms the phrase of 8 measures: 2 phrases constitute the square period (16 measures). Contractions and dilations of phrases or of half-phrases can produce an irregular squareness. The square type is found in the forms of the canzone, of the Lied, of the hymn, and, independently of a poetic text, in dance forms (instrumental strophic melody). But strophicity does not always mean squareness, just as strophe does not always mean verse. Even a non-versified text can have strophicity, and likewise musical discourse is strophic if it proceeds by closed periods, though not necessarily of 16 measures.
2) Multiple (or thematic) melody. - In polyphony, the discourse is woven of themes that link to one another, reproduce themselves, modify themselves, generate others, pass from one voice to another, pervading all the parts with themselves.
3) Infinite melody. - Free from cadential symmetries and from conclusions of a strophic nature, it does not for that reason proceed without a logic of its own, but this logic is reduced to a pure necessity of effusion in continuous renewal. The most luminous examples are given by melismatic chant in the liturgy (Gregorian graduals and alleluias; Ambrosian psalmelli and alleluias).
Edgardo Carducci Agustini