Distinction Between Bipartite And Tripartite Forms

We learned, in the

preceding chapter, that the Two-Part Song-form is a composition of

rather brief extent, with so decisive a perfect cadence in its course

as to divide it, in a marked manner, into two separate and fairly

individual sections or Parts.

Between this and the next higher form,--that with three such

Parts,--there is a distinction far more essential and characteristic

than that of
ere extent; a distinction that does not rest simply upon

the number of Parts which they respectively contain. Each of the two

classes of formal design, the Two-Part and the Three-Part, embodies a

peculiar structural idea; and it is the evidence of these respective

ideas,--the true content of the musical form,--which determines the

species. The number of sections is, in this connection, nothing more

than the external index of the inherent idea.

The Two-Part forms embody the idea of progressive growth. To the

first Part, a second Part (of similar or related melodic contents) is

added, in coherent and logical succession. It should not be, and in

good clear form it is not, a purely numerical enlargement, for the

association of the second Part with a foregoing one answers the

purposes of confirmation and of balance, and is supposed to be so

effectuated as to institute and maintain unity of style, and some

degree of progressive development. But the second Part, in this

bipartite design, does little or nothing more, after all, than thus to

project the musical thought on outward in a straight line (or along

parallel lines) to a conclusion more or less distant from the

starting-point,--from the melodic members which constitute the actual

germ, or the text of the entire musical discourse. A very desirable,

not to say vital, condition is therefore {90} lacking, in the Two-Part

forms; namely, the corroboration of this melodic germ by an emphatic

return to the beginning and an unmistakable re-announcement of the

first (leading) phrase or phrases of the composition.

Nothing could be more natural than such corroboration. Any line of

conduct, if pursued without deviation, simply carries its object

farther and farther away from its origin. If, as in the circle, this

line is led back to the starting-point, it describes the most

satisfying and perfect figure; it perfects, by enclosing space.

Whereas, if it goes straight onward, it ultimately loses itself, or

loses, at least, its connection with its beginning and source.

Nowhere is this principle of Return more significant and imperative

than in music, which, because of its intangibility, has need of every

means that may serve to define and illuminate its design; and hence the

superior frequency and perfection of the Three-Part form, which, in

its Third Part, provides for and executes this Return to the

beginning. Its superiority and greater adaptability is fully

confirmed in the practice of composition; the number of Three-Part

forms exceeds the Two-Part, in musical literature, to an almost

surprising degree; and it may therefore be regarded as the design

peculiarly adapted to the purposes of ordinary music writing within

average limits.

The three successive divisions of the Three-Part Song-form may then be

characterized as follows:--