example of Bach, in order that it may be compared with the scheme of Mozart's form, which will be given later. A little Air in the Suite Francaise No. 4, in E♭ major, sets out with a clearly defined figure which may be called the 'first subject,' and modulates in the fourth bar to the key of the Dominant, in which the figure which may also be called by analogy the 'second object' appears, and with this the first half of the movement concludes. The second half sets out with modulations and hints at the figures of the first half, after 10 bars comes to a pause on the Dominant of the original key, and from thence recommences the first subject; and the latter part of the section being deftly altered by a device of modulation—of which Mozart made great use in the same position in the movement—enables the whole of the last 4 bars of the first half of the movement to follow also in E♭, so concluding the Air.
There is no need to give a like detailed analysis of the Allegro in Handel's Suite No. 14, in G. It will suffice to point out that its form is identical with the preceding on a large scale; and that it is clearer and easier to recognise, inasmuch as the sections do not flow so closely into one another, and the subjects are more definite. These two examples are however exceptional as regards both Bach and Handel and their immediate successors. The tendency was still for a time to adopt the form of reproducing the first subject at the commencement of the second half of the movement; and in point of fact it is not difficult to see why it was preferred, since if nothing else could be said for it, it certainly seemed to keep the balance of the keys more equal. For by this system the subject which appeared in the principal key in the first half came in in the complementary key in the second half, and the second subject vice versâ, whereas in the later system the first subject always appears in the principal key. Moreover the still older system of merely repeating the ending of the first half still lingers on the scene after the time of Bach and Handel, for in a Sonata by Galuppi (1703–85 [App. p.637 "1706–85"]) in D (published in Pauer's 'Alte Clavier Musik') there is a charming little opening Adagio which seems to look both forwards and backwards at once; for its form is a clear specimen of the mere repetition of the concluding phrase of the first part at the conclusion of the whole, while its soft melodious manner and characteristic definition of sections by cadences and semi-cadences (tending to cut it up into so many little tunes), make it in spirit a very near relation of Mozart's. And one might take this little movement, without much stretch of imagination, as the final connecting link between the movements which look back towards the primitive form as displayed in the original Branle, and those which look on towards the Mozart and Haydn epoch. The other movements of Galuppi's Sonata are in the more developed form, in which the first subject is quoted at the commencement of the second half of the movement.
In Galuppi's contemporary, P. D. Paradies, we find even a closer relationship to Mozart in many respects. The first movement of his Sonata in A, for instance, is on an extended scale. His subjects are clearly defined, and the growing tendency to cut the movement up into sections is still clearer than in Galuppi. The subjects are definitely restated, but after the earlier manner, with the first subject reproduced at the beginning of the second half. It is however noticeable that in the lively Finale of this Sonata the subjects both reappear at the end of the whole.
If we turn to the distinguished German composers of this epoch we find ourselves as it were among the immediate exemplars of Haydn. In them both the manner and form of their great successors are prefigured, and there is no longer any doubt about the basis of construction of the movement; the first part being as it were the thesis of the subjects, and the second part their discussion and re-statement; but there is still an uncertainty with regard to the respective positions of the re-statements. If, for instance, we examine a Sonata of Johann Christian Bach, op. 17 (Pauer's 'Alte Clavier Musik'), we find a very clear and extended specimen of the older system. The first half has a very long section in the principal key (B♭), and another section, also long, in the Dominant key (F)—all of which is as usual repeated. The second half commences with a clear statement of the first section in the Dominant key, followed by development and modulation, and pausing on the Dominant of the original key of B♭, in which all the second section of the first part is reproduced with an exactness which is almost tiresome. It is worthy of remark that the last movement is in the Gigue time and style without being so named, and is a happy instance of the gradual complete mergence of the old dance Suite in the Sonata. As a reverse to this picture there is a Bourée in a Suite by Johann Ludwig Krebs—a contemporary of Johann Christian Bach, and one of the most distinguished of his father's pupils—which, though called by the old dance name, is in perfect modern form, and shows so aptly the transition of the repeated ending of the first part into a second subject that it is worth quoting in outline.
- The slow movement of Beethoven's Quartet in D major, Op. 18, is an example of this form.