[29] Arrangement for piano, two hands, in the Peters edition. Number the measures throughout. There are three hundred and seven. The general structure will be seen at a glance in the appended tabular view.
[30] This is according to custom in movements written in minor keys. The second theme is in such cases usually put in the relative major instead of in the dominant. (See the chapter on "Folk-Song.")
CHAPTER X.
THE SLOW MOVEMENT.
I. VARIETIES OF FORM.
In the classical sonata the usual arrangement of movements was as follows: (1) Allegro (in "Sonata-form"): (2) Adagio or Minuet: (3) Finale (usually a rondo).
Occasionally—as in Mozart's Piano Sonata in A-major—the slow movement, in the form of a theme and variations, was placed at the beginning, and in that case the order would be (1) Theme and Variations, (2) Minuet (3) Finale. The symphony, which, it must be remembered, was a sonata on a large scale—always began with a movement in sonata-form, and had four movements. Although the sonata was subject to many outside influences—most important of which were polyphony and the old overture and other operatic forms—its two main sources were dance tunes and folk-songs. The evolution of the dance tune through Bach's polyphonic gavottes, sarabandes, etc., has already been traced in Chapters IV, V, and VI, and the influence of the dance on the first movement in Chapters VIII and IX.
The slow movement is ultimately derived from the folk-song, and, while more subject to operatic influence than were the other movements, it still retains something of that simple lyric quality that distinguished it in its primitive form. Unlike the other movements of the sonata and symphony, however, the slow movement has no settled form: i. e., while we speak of first-movement, or sonata-form, of the rondo form, and of the minuet form, we do not speak thus of "slow movement form." For in the slow movement style rather than form is of greatest importance. On account of its slow tempo it is shorter than the first movement, and consequently not so dependent for intelligibility on formal structure. Its themes, also, are song-like in character, and song themes, being in themselves complete, do not lend themselves readily to development—do not generate new material—as has already been pointed out. As a consequence the slow movement is usually written in what we call a "sectional" form: i. e., a series of sections following one another according to whatever order or system the composer may choose. The most common use is, however, the form employed in the minuet. But in slow movements the long song themes, somewhat elegiac in style and full of sentiment, make the mood of each section of supreme importance, and throw the formal element into the background. So that, while the slow movement usually falls under some one of the common forms already discussed, it often modifies them in one way or another.
There are rare instances of developed ternary form in the slow movements of Mozart's pianoforte sonatas. The Andante of the Sonata in B-flat (no. 10 in Schirmer's edition), has a development section. It comprises only nineteen measures, however, and its effect as a section germinating from the exposition is somewhat lessened by the scheme of repeats, which is as follows: A :⎜⎜: B. A. :⎜⎜. The use of rondo form in the slow movement will be discussed in a later chapter.