Chapter 30

EVOLUTION.--It cannot have escaped the observant student of the foregoing pages, that the successive enlargement of the structural designs of musical composition is achieved by a process of natural growth and progressive evolution. No single form intrudes itself in an arbitrary or haphazard manner; each design emerges naturally and inevitably out of the preceding, in response to the necessity of expansion, and conformably with the same constant laws of unity and variety,--the active agents, along the entire unbroken line of continuous evolution, being _reproduction_ (Unity) and legitimate _modification_ (Variety); or, in other words, _modified repetition_. It is upon the indisputable evidence of such normal evolution in the system of musical structure, that our conviction of the legitimacy and permanence of this system rests.

The diagrams which appear on pages 78 and 98 partly illustrate the line of evolution, which, in its fullest significance, may be traced as follows: the _tone_, by the simplest process of reproduction, became a _figure_; the figure, by multiplication or repetition, gave rise to the _motive_; the latter, in the same manner, to the _phrase_. The repetition of the phrase, upon the infusion of a certain quality and degree of modification (chiefly affecting the cadences) became the _period_; the latter, by the same process, became the double-period. The limit of coherent phrase-succession (without a determined interruption) being therewith reached, the larger Part-forms became necessary. The _Two-Part_ form emerged out of the double-period, the two "connected" periods of which separated into two "independent" Parts, by the determined interruption in the center. And, be it well understood, each new design having once been thus established, its enlargement within its own peculiar boundaries followed as a matter of course; I mean, simply, that the two Parts did not need to remain the _periods_ that were their original type; the process of growth cannot be stopped. The _Three-Part_ form resulted from adding to the Two-Part the perfecting reversion to the starting-point, and confirmation of the principal statement. The _Five-part_ form, and the _Song with Trio_ are enlargements of the Three-Part forms by repetition or multiplication; and with the latter the limit of this particular process appears to be achieved. Any further growth must take place from within, rather than by addition from without.

But the process of evolution continues steadily, as the student will witness. To one vital fact his attention is here called,--a fact which he is enjoined to hold in readiness for constant application,--namely, _that perfection of structural design is attained in the Three-Part form, and that every larger (or higher) form will have its type in this design, and its basis upon it_. The coming designs will prove to be expansions of the Three-Part form.

THE RONDO-FORMS.--The structural basis of the Rondo, and other larger or (as they are sometimes called) higher forms, is the Subject or Theme. The form and contents of this factor, the Theme, are so variable that a precise definition can scarcely be given. It is a musical sentence of very distinct character, as concerns its melodic, harmonic and, particularly, its rhythmic consistency; and of sufficient length to establish this individuality,--seldom, if ever, less than an entire period or double-period; often a Two-Part, not infrequently a complete Three-Part Song-form, though never more than the latter.

In the Rondo-forms, two or three such Themes are associated in such _alternating succession that, after each new Theme, the first or Principal Theme recurs_. The term "Rondo" may be referred to this trait, the periodic return of the Principal theme, which, in thus "coming round" again, after each digression into another theme, imparts a characteristic circular movement (so to speak), to the design. In the rondos, then, all the movements of musical development revolve about one significant sentence or theme, the style of which therefore determines the prevailing character of the whole composition. This, which is naturally called the Principal theme, is placed at the beginning of the rondo. Its end being reached, it is temporarily abandoned for a second sentence, called the Subordinate theme, of more or less emphatically contrasting style and of nearly or quite equal length (generally shorter, however), and always in a different key. After this there occurs the momentous _return to the beginning_,--the most insistent and vital fundamental condition of good, clear, musical form, of whatsoever dimension or purport,--and the _Principal_ theme reasserts itself, recurring with a certain degree of variation and elaboration (occasionally abbreviation), thus vindicating its title as Principal theme, and stamping its fellow-theme as a mere digression. After this,--if a still broader design is desired,--another digression may be made into a new Subordinate theme, in still another key, followed by the persistent return to the Principal theme. And so on. Upon the Subordinate theme, or themes, devolves the burden of variety and contrast, while the Principal theme fulfils the requirements of corroboration and concentration. A coda, sometimes of considerable length, is usually added; it appears to be necessary, as a means of supplying an instinctive demand for balance, increased interest, and certain other scarcely definable conditions of very real importance in satisfactory music form.

Of the Rondo-forms there are three grades, distinguished respectively _by the number of digressions_ from the Principal theme:--

The First Rondo-form, with one digression (or Subordinate theme), and one return to the Principal theme;

The Second Rondo-form, with two digressions, and two returns;

The Third Rondo-form, with three digressions and three returns. The persistent recurrence of the Principal theme, something like a refrain, and the consequent regular alternation of the chief sentence with its contrasting subordinate sentences, are the distinctive structural features of the Rondo.

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THE FIRST RONDO-FORM.--This consists, then, of a Principal theme (generally Two-Part or Three-Part Song-form); a Subordinate theme in a different key (probably a smaller form); a recurrence of the Principal theme (usually more or less modified or elaborated); and a coda. Thus:--

_Principal Theme. Subordinate Theme. Prin. Theme. Coda._ 2- or 3-Part Period, Double-period, As before, Optional Song-form. 2- or 3-Part usually Probably a form. Different variated. perfect cadence. style and key. Sometimes Possibly a few Possibly a brief abbreviated. beats or measures codetta; and of transitional usually a few material, leading measures of into next theme. Re-transition.

The design is that of the tripartite forms. But it is not to be confounded with the Three-Part _Song-form_, because at least one of its Themes, and probably both, will be a Part-form by itself. It is an association of Song-forms, and therefore corresponds in design to the _Song with Trio_. The first Rondo differs from the latter, however, in being more compact, more coherent and continuous, and more highly developed. This manifests itself in the relation of the Themes to each other, which, despite external contrast, is more intimate than that between the Principal and Subordinate Song (or Trio); further, in the transitional passages from one Theme into the other (especially the Re-transition, or "returning passage"); in the customary elaboration of the recurring Principal Theme; and in the almost indispensable coda, which often assumes considerable importance, and an elaborate form and character.

The evolution of the First Rondo-form of the Song with Trio may be clearly traced in classic literature. Many intermediate stages appear, naturally; and it is sometimes difficult to determine whether the design is Rondo or compound Song-form, simply because it is scarcely possible to decide just when the "Trio" assumes the more intimate relation of a Subordinate theme, or when the freedom and comparative looseness of association (peculiar to the Song with Trio) is transformed into the closer cohesion and greater smoothness of finish _which fuses all the component Parts of the design into one compact whole_,--the distinctive stamp of all so-called "higher" forms.

The thoughtful examination and comparison of the following four examples will elucidate the matter:--

1. Beethoven, first pianoforte sonata (op. 2, No. 1), _Menuetto_ and _Trio_. Already analyzed as a perfectly genuine Song with Trio.

2. Beethoven, pianoforte sonata, op. 28, second movement, _Andante_. The principal Song is in the Three-Part form, with exact repetitions. The subordinate song differs so radically in style, and each song is so complete and distinct from the other, that the form is almost certainly Song with Trio; but there is a strong intimation of the Rondo-form in the elaborate variation of the _da capo_, and in the treatment of the coda (last 17 measures), in which motives from both Songs are associated so closely as to vindicate their kinship. In a word, this movement possesses,--despite the apparent independence of its Songs,--some degree of that continuity, compactness and artistic finish which culminate in the genuine Rondo-form.

3. Mozart, pianoforte sonata, No. 10, second movement (_Rondeau en polonaise_). The continuity and unity of this composition is so complete that it is certainly a Rondo-form; the principal theme is a fairly large Three-Part form; the subordinate theme (measure 47-69) is a Two-Part form, the second part corresponding in contents to the second Part of the principal theme; the _recurrence_ of the principal theme is abbreviated to one of its three Parts, and is merged in the coda (last seven measures), which assumes the nature of a mere extension. Despite all this evidence, there still remains a certain impression of structural independence, which, so to speak, betrays the "seams," and militates somewhat against the spirit of the perfect Rondo-form. See also, No. 13, Adagio.

4. Beethoven, pianoforte sonata, op. 2, No. 2, _Largo_; the unessential details omitted in the following (in order to economize space) appear, of course, in the original,--to which the student is expected to refer.

This is a genuine First Rondo-form. All the factors of which it is composed, Phrases, Parts and Themes, are so closely interlinked that the continuity, cohesion and _unity_ of the whole is complete. The variety of contents which these factors exhibit (greatest, naturally, between the two themes), does not disturb the impression that the whole movement is a unit. This is due, at least partly, to the manner in which the perfect cadences are disguised; each one is passed over with the least possible check of rhythmic movement (measures 8, 19, etc.), thus snugly dove-tailing the structural factors. The coda is elaborate and unusually long; it consists of several "sections," as follows (see the original): from measure 1 (the last measure in Ex. 54) to measure 4, a phrase, derived from the second Part of the Principal theme; measures 5-7, an abbreviated repetition; measures 8-14, a phrase, derived from the Principal theme; measures 15-17, a transitional passage; measures 18-25, a period, closely resembling Part I of the Principal theme; measures 26-30, final phrase.

LESSON 13.--Analyze the following examples. They are not classified; the student must determine whether the form is pure First Rondo, or an intermediate grade between Rondo and "Song with Trio." One of the examples is a genuine Song with Trio; and one is a _Three-Part Song-form_; with reasonable vigilance the student will detect these "catches." To distinguish these three designs from each other, recollect--

That the Three-Part Song-form consists of three _single Parts_, fairly similar in character, fairly small in form, and severed either by a firm cadence, or by unmistakable proof of new "beginning;"

That in the first Rondo-form, at least one of the themes (if not both) contains _two_ (or three) Parts; and,

That in the Song with Trio, the two "Songs" are more independent of each other, and more decisively separated, than are the "themes" of the Rondo-form.

With reference to all uncertain cases, it must be remembered that _the more doubtful a distinction is, the less important is its decision_. These designs naturally merge one in another, and at times it is folly to impose a definite analysis upon them.

The analysis should be as minute as possible, nevertheless. The first step is to define the extremities of the two themes. This fixes the coda (and the introduction, if present); the re-transition (returning passage into the Principal theme); and the transition into the Subordinate theme--if present. The form of each theme must be defined in detail, as in Ex. 54:--

Beethoven, pianoforte sonatas: op. 2, No. 1, _Adagio_.

Op. 7, _Largo_.

Op. 2, No. 3, _Adagio_.

Op. 79, _Andante_.

Op. 27, No. 1, _Allegro molto_.

Schubert, pianoforte _Impromptus_, op. 90, No. 2; and No. 3.

Chopin, _Mazurka_, No. 26.

Chopin, _Nocturnes_: op. 27, No. 1.

Op. 32, No. 2.

Op. 37, No. 2.

Op. 48, No. 1.

Op. 55, No. 1; and No. 2

Op. 62, No. 1.

Op. 72, No. 1 (E minor, posthumous).