which it is not. They are generally constructed out of materials taken from the movement, which are usually presented in some new light, or associated together in a fresh manner; and the form is absolutely independent. Modulation is rarely to be found, for the intention of the Coda was to strengthen the impression of the principal key at the conclusion, and musicians had to be taught by Beethoven how to do this without incessantly reiterating the same series of chords in the same key. As an instance of the consideration and acuteness which characterise Haydn's very varied treatment of forms may be taken the Coda of the first movement of the Symphony in C, No. 1 of the Salomon set. In this movement he misses out certain prominent figures of the first section on its repetition in the second half, and after passing on duly through the recapitulation of the second section he takes these same omitted figures as a basis whereon to build his Coda. Many similar instances of well-devised manipulation of the details of form are scattered throughout his works, which show his remarkable sagacity and tact. They cannot be brought under any system, but are well worth careful study to see how the old forms can be constantly renewed by logically conceived devices, without being positively relinquished.
Haydn represents the last stage of progress towards clear and complete definition of abstract Form, which appears in its final technical perfection in Mozart. In Mozart Form may be studied in its greatest simplicity and clearness. His marvellous gift of melody enabled him to dispense with much elaboration of the accepted outlines, and to use devices of such extreme simplicity in transition from one section to another that the difficulty of realising his scheme of construction is reduced to a minimum. Not that he was incapable of elaborating his forms, for there are many fine examples to prove the contrary; but it is evident that he considered obviousness of outline to be a virtue, because it enabled the ordinary hearer as well as the cultivated musician to appreciate the symmetrical beauty of his compositions. Apart from these points of systematic definition Mozart was not an innovator, and consequently it will not be necessary to point out his advances on Haydn. But inasmuch as he is generally recognised as the perfect master of the formal element in music it will be advisable to give an outline of his system.
The first section, which tends to mark clearly the principal key of the movement, sets out with the principal subject, generally a tune of simple form, such as 8 bars divided into corresponding groups of four (see the popular Sonata in C minor). This is either repeated at once or else gives place to a continuation of less marked character of figure, generally commencing on the Dominant bass; the order of succession of this repetition and continuation is uncertain, but whichever comes last (unless the section is further extended) usually passes to the Dominant key, and pauses on its Dominant; or pauses without modulation on the last chord of a half close in the original key; or, if the key of the whole movement be minor, a little more modulation will take place in order to pass to the key of the relative major and pause on its Dominant. The second section—which tends to define clearly the complementary key of the movement, whether Dominant or Relative major to the original—usually starts with a new subject somewhat contrasted with the features of the first section, and may be followed by a further accessory subject, or derivative continuation, or other form of prolongation, and so passes to the frequent repetition of the cadence of the complementary key, with either brilliant passages, or occasionally a definite fresh feature or subject which constitutes the Cadence episode of the first part. These two sections—constituting the first half of the movement—are usually repeated entire.
The second half of the movement commences with a section which is frequently the longest of all; it sometimes opens with a quotation of the first subject, analogous to the old practice common before Haydn, and proceeds to develop freely the features of the subjects of the first part, like a discussion on theses. Here cadences are avoided, as also the complete statement of any idea, or any obvious grouping of bars into fixed successions; modulations are constant, and so irregular that it would be no virtue to find the succession alike in any two movements; the whole object being obviously to produce a strong formal contrast to the regularity of the first half of the movement; to lead the hearer through a maze of various keys, and by a certain artistic confusion of subject-matter and rhythm to induce a fresh appetite for regularity which the final return of the original subjects and sections will definitely satisfy. This section Mozart generally concludes by distinctly modulating back to his principal key, and either pausing on its dominant, or passing (perhaps with a little artistically devised hesitation), into the first subject of the movement, which betokens the commencement of the fourth section. This section is usually given without much disguise or change, and if it concludes with a pause on the Dominant chord of the original key (i.e. the final chord of a half close), will need no further manipulation, since the second subject can follow as well in the original key as in that of the Dominant, as it did in the first part. If however the section concludes on the Dominant of that Dominant key in the first half of the movement, a little more manipulation will be necessary. Mozart's device is commonly to make some slight change in the order of things at the latter part of the section, whereby the course of the stream is turned aside into a Sub-dominant channel, which key standing in the same relation to the principal key that the principal key stands to the Dominant, it will only be necessary to repeat the latter part of the section in that key and pause again on the Dominant of the original key, in which the
- In the first movement of the 'Jupiter' Symphony so exact is the repetition, that in one of the editions a passage of 21 bars is not reprinted, but a reference 'Da Capo' is made to its occurrence at the beginning of the Allegro.