This is followed by 7 more bars of development after the manner of this commencement, modulating to C minor and A♭ and thence back to E♭, in which key the first subject is resumed as follows:—
In this the passage from (a) to (b) constitutes the first subject and section ; and that from (b) to (c) the second, in the Dominant key, corresponding to a 'second subject'; then follow the development and modulation, from (c) to (d); and then the repeat of the first section in the principal key, with the little cadence figure (e), which is treated in precisely the manner that a second subject would be treated in a more extended movement, being given complete, transposed from the Dominant key to the original Tonic. That Krebs had well defined his own objects in these matters is clear from the fact that the Polonaise from the same suite, and an Allemande from another in B♭ are constructed after precisely the same system.
There remains yet the most important predecessor of Haydn, namely Emmanuel Bach, in whose Sonatas Form reached a very remarkable pitch of perfection. Many of them stand in a very peculiar relation both to the old order and to the new which was destined to supplant it on the principle of the survival of the fittest; for they present examples of the reappearance of the first subject at the commencement of the second half of the movement, as well as after the section devoted to development and modulation—in other words, both in its older position and in its recognised place in modern instrumental works. This is the case in the Sonata in G in the first collection published at Leipzig in 1779, and in Bülow's little selection of Six. The same also in the last movement of the Sonata in A (which is both in Bülow's collection and in Pauer's 'Alte Meister'), and in the first movement of the Sonata in F minor from the third set of Clavier Sonatas, also edited by Bülow. The sonata in D minor approaches more nearly to modern ways in the position of the repetition of the first subject in the second part; but offers a marked instance of independent thought in reproducing the second subject in the key of the third below the Tonic (that is, in B♭ relative to D), and afterwards passing back to the principal key, and reproducing the rest of the materials of the section after the usual manner—thus in some respects anticipating Beethoven.
A great deal more might be said on the individual and thoughtful use of Form which is observable in the works of Emmanuel Bach; but it will be merely necessary to point out that the study of them as works of art, by those who are as yet unacquainted with them will throw quite a new light on Haydn and Mozart. He has been called their forerunner, and he thoroughly justifies the title not only by the clearness and distinctness of his form, but by certain undefinable qualities of style and sentiment. Something of this may be due to his view that music should be interpreted as vocally as possible (see Burney, vol. iv. chap, x.), which is also a very distinguishing trait of the Mozart school. It must also be noted that in him the continuous fugal manner seems finally to have yielded before the growing predominance of the essentially distinct modern harmonic style. The forms of the fugal style, such as they were, were rather relative than positive, and depended upon certain laws—not very clearly defined or consistently observed—as to the modes of recurrence of the subjects; whereas the forms of the modern harmonic style are positive and systematic. The forms of the fugal style may be compared to the composition of lines and curves in a drawing, in which they are not preconceived, but grow into completeness by the attention which is bestowed by the artist on their relations to one another. Whereas the forms of the harmonic style are architectural, and are governed by certain necessary prior considerations as vital as that of roof and walls to the architect, whereby the movement comes to be divided into sections chiefly based upon the succession of keys, in which the various subjects are rather indicators of outline than positive elements of construction. In Emmanuel Bach we find a number of figures and subjects characteristic of each of the primary sections, as we do in Beethoven; and the spirit of his great father, though attenuated enough, is yet perceptible in his manner of treating short and pregnant figures, and in some peculiarities of phraseology. These are probably the chief points of connection between the spirit of the great giant and the graces of the less austere style of Haydn and Mozart.It can hardly be doubted that the realisation of this practically new discovery of the element of positive harmonic or Tonal form in music must have acted like many other fresh discoveries in the realms of art, and tended to swamp the other elements of effect; making composers look to form rather as ultimate and preeminent than as inevitable but subsidiary. It seems not improbable that the vapid and meaningless commonplace which often offends the sensitive musician in the works of Haydn and Mozart, and appears like just so much rubbish shot in to fill up a hole, was the result of this strong new feeling for form as paramount, and that it remained for Beethoven to reestablish definitely the principle of giving equal intensity to every part of the piece in proportion to its importance. With Haydn and Mozart it is frequent to find very sweet tunes, and sometimes very serious and pregnant tunes, in each of the primary sections, and then a lot of scurrying about—'brilliant passages' as they are often called—the only purpose of which is to mark the cadence, or point out that the tune
- Von Bülow, Preface.