OMOPHONIC FORMS, Chapters 9
and 10.

LESSON 9.--Analyze the following examples of the Two-Part Song-form.
Define the form of each Part, marking and classifying all cadences; and
indicate introductions and codas (or codettas), if present. _The first
step in the analysis of these forms is to divide the whole composition
into its Parts, by defining the end of Part One_. The next step is to
define the beginning of Part One, and end of Part Two, by separating
the introduction and coda (if present) from the body of the form.

Beethoven, pianoforte sonatas: op. 57, Andante, Theme.

Op. 109, _Andante_, Theme.

Op. 111, last movement, Theme of Variations.

Op. 79, _Andante_, first 8 measures (unusually small); same sonata,
last movement, first 16 measures.

Op. 54, first 24 measures (each Part repeated).

Op. 31, No. 3, _Menuetto_ (without Trio).

Op. 26, "Trio" of _Scherzo_; also last movement, first 28 measures
(second Part repeated).

Op. 27, No. 2, "Trio" of _Allegretto_.

Mozart, pianoforte sonatas: No. 2 (Peters edition), _Andante_, measures
1-20; and measures 21-40.

Schumann, op. 68, No. 7; No. 4; No. 35; No. 42; No. 23 repeated; last
16 1/2 measures, (coda).

CHAPTER X.--THE THREE-PART SONG-FORM.

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 mere 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