Sometimes, but by no means regularly, the Exposition closes with a decisive perfect cadence in the original key.
The Middle Division.—As this should balance (at least approximately), the Exposition, it is likely to be a fairly broad design,—not greater, however, than a Three-Part Song-form (possibly with repetitions), and often no more than a Two-Part form. As intimated in the preceding chapter, the Second Subordinate theme is usually strongly contrasted with the other themes, in character, key, and length; but the same unity of total effect is necessary, as in the smaller Rondo-forms. The re-transition (or returning passage) is often quite lengthy and elaborate; it is seldom an independent section of the form, however, but generally developed out of the last phrase of the theme, by the process of "dissolution,"—to be explained more fully in Chapter XVII.
THE RECAPITULATION.—This corresponds, theoretically, to the da capo in the Song with Trio, or to the variated recurrence of the Principal theme in the First Rondo-form. But it is more than either of these. The term "Recapitulation" is more comprehensive than "recurrence" (in the sense in which we have thus far employed the latter word), as it always refers to the reproduction of a collection of themes, and, chiefly on this account, is subject to certain specific conditions of technical treatment.
Recapitulation, in the larger designs of composition, invariably involves transposition, or change of key,—the transposition of the First Subordinate theme, from the key chosen for its first announcement (in the Exposition) back to the principal key of the piece. This, as may be inferred, greatly affects the original transition and re-transition; and it may necessitate changes within the theme itself, in consequence of the change of register.
Further, the last recurrence of the Principal theme being no less than its fourth announcement, is rarely complete; as a rule, a brief intimation (the first motive or phrase) is deemed sufficient, and this is then dissolved into the coda; or the Principal theme, as such, is omitted, or affiliated with the coda, or one of its sections.
{119}
For an illustration of the Third Rondo-form, the student is referred to the last movement of Beethoven's pianoforte sonata, op. 2, No. 2, the diagram of which is as follows:—
| Exposition | Middle Division | Recapitulation | ||||
| Pr. Th. | 1st Sub. Th. | Pr. Th. | 2d Sub. Th. | Pr. Th. | 1st Sub. Th. | Pr. Th. and Coda |
| A maj. | E maj. | A maj. | A minor | A maj. | A maj. | A maj. |
For its detailed analysis, number the measures as usual (there are 187, the "second ending" not being counted), and define each factor of the form by reference to the given indications,—the figures in parenthesis again denoting the measures:—
Principal Theme, Part I (1-8), period-form. Part II (9-12), phrase. Part III (13-16), phrase.