ree Divisions_,--the Exposition, a middle
Division called the Development (growing out of the brief interlude of
the sonatine-form), and the Recapitulation. The diagram (the keys of
which correspond to the plan of Beethoven, op. 14, No. 2, first
movement) is as follows:

Exposition. Middle Div. Recapitulation.
---------------------- ------------- -------------------------
Pr. Sub. Codetta. Development, Phr. Sub. Codetta
Th. Th. various keys, Th. Th. and Coda.
---------------------- ending with -------------------------
G maj. D maj. D maj. Retransition. G maj. G maj. G maj.

Compare this diagram, also, with that of the Third Rondo-form, and
note, accurately, the points of resemblance and contrast.

Compare it, further, with the diagram of the sonatine-form, on page
122. It will be observed that here the Recapitulation does not follow
the Exposition at once, as there, but that a complete middle division
intervenes, instead of the brief interlude or re-transition; from which
the student may conclude that the sonatine-form gradually grows into
the sonata-allegro form, as this interlude becomes longer, more
elaborate, and more like an independent division of the design. Or
inversely, and perhaps more correctly, the sonata-allegro becomes a
sonatine-design _by the omission (or contraction) of the middle
Division_.

THE EXPOSITION.--The presentation of the thematic factors, the
statement or Exposition of the two themes and codetta, is made exactly
as in the sonatine-form, though probably upon a broader scale. The
Principal theme is usually a Two-Part Song-form, at least; often
Three-Part. In broader designs, a separate transitional passage
appears; in more concise designs, the transition is developed out of
the last Part of the Principal theme by the process of dissolution--as
will be seen. The object of the transition is, as usual, _to lead into
the new key_ (of the Subordinate theme). It is sometimes, though very
rarely, omitted.

The Subordinate theme contrasts notably with its fellow, but asserts
equal importance, as a rule, and may be of equal, or nearly equal,
length. The addition of a codetta is almost indispensable, and
frequently two or more appear, growing successively shorter, and
generally repeated. In the sonata-allegro _the Exposition closes, as a
rule, with a very decisive perfect cadence_, followed by a double-bar,