CHAPTER V

THE TWO-PART AND THREE-PART FORMS

Now that a clear insight has been gained into the formation of the normal sentence, we are in a position to understand how sentences may be combined to make complete compositions. The simplest and most primitive structure is that which contains _two_ complete sentences; dividing itself naturally into _two_ parts and hence known as the Two-Part Form. This form by reason of its simplicity and directness is often found in the short pianoforte pieces of Schumann, Tchaikowsky, Brahms, Grieg and Debussy. For a long period there was no attempt at differentiation between vocal and instrumental style; music, in fact, during the 15th and 16th centuries was often entitled "buon da cantare ou suonare," _i.e._, equally well suited for voices or instruments. When instrumental players were in search of pieces, they simply transferred to their instruments the voice-parts of the Madrigals and Canzonas which were then so fashionable.[63] With the development of instruments--especially of the Violin family--and with the desire for an instrumental style which should be independent of words, principles of coherent design had to be evolved; and they were suggested by the definite metre in the stanzas of the Folk-song and, above all, by the symmetrical phrases of the Folk-dance, used to accompany the _rhythmical_ motions of the body. By a utilization of these principles of balanced phrases, of contrasted keys and of periodic themes, instrumental music gradually worked out a structure of its own,[64] of which we find examples in National dances and in the compositions of such pioneers of instrumental style as the Italians Corelli and Vivaldi, the Frenchmen Lully, Couperin and Rameau, and the Englishman Purcell.

[Footnote 63: For a complete account of this process see Parry's _Evolution of the Art of Music_, p. 115 _seq._]

[Footnote 64: This book makes no attempt to give an historical account of the development of instrumental form. The subject is set forth comprehensively in the article on Form in Grove's Dictionary (Vol. II, p. 73) and in the Fifth and Sixth Chapters of Parry's _Evolution of the Art of Music_.]

[Music:

Viens dans ce bocage belle Aminte, Sans contrainte L'on y forme des voeux; Viens, Viens dans ce bocage belle Aminte, Il est fait pour les plaisirs et les jeux.]

In this rhythmic and sprightly dance of exactly 8 measures (an old French _Tambourin_ taken from Weckerlin's _Echos du Temps Passé_) we see clearly the influence of the metrical stanza of words and of the balanced phrases in the instrumental part, necessary to accompany the steps of the dancers. The melody of the accompaniment was played on a flute or some simple kind of pipe, and the bass on a Tambour de Basque--a rude form of drum, which repeated continually the tonic and dominant of the key; the same effect which we associate with the Bagpipe and Hurdy-gurdy.

[Music: PURCELL: Jig.]

In this Jig, which was a favorite type with the English peasantry--divided into three sentences of exactly 8 measures each--the dance rhythm is very sharply defined. From various dance-patterns a structural type was gradually evolved, of which the chief features will now be indicated. The music was divided into _two_ distinct halves and it became the convention to gain length by repeating each half--in the early days of the form, _literally_ (with a double bar and sign of repeat); later, as composers gained freedom, with considerable amplification. Each half presented the _same_ material (it was a _one_-theme form) but the two halves were contrasted in _tonality_, _i.e._, the first part, beginning in the home-key, would modulate to some related key--generally the dominant; the second part, starting out in this key, gradually modulated back to a final cadence in the original key, and often--especially in Haydn and Mozart--repeated the entire main sentence of the first part. The general effect of such a form has been wittily described[65] as resembling the actions of "the King of France who, with twenty thousand men, marched up the hill and then marched down again"--but he surely had no exciting adventures in between! It is evident that this form, while favorable to coherence and unity, is lacking in scope and in opportunity for variety and contrast. It did, however, emphasize the principle of recapitulation; in fact it became the convention (as we shall see in the dances of the Suite) for the closing measures of the second part to be an exact duplicate in the home-key of that which had been presented at the end of part one. We shall observe, as we continue our studies, that the trend of musical composition gradually swung over to the Three-part form, the essential feature of which is restatement after _intervening contrast_.

[Footnote 65: See _The Appreciation of Music_ by Surette and Mason, p. 36.]

For illustrations of the Two-part Form see the Supplement Nos. 20, 21, 22, 23, 24.

Only in such comparatively simple examples as those just cited is found this perfect balance in the length of the two parts. We often observe extended sentences in the first part; and it became the custom for the second part to be considerably lengthened, to include modulations into more remote keys and even to display certain developments of the main material. For a striking example of a movement which, although definitely in Two-part form, (_i.e._, it is in two clear divisions and has but _one_ theme) is yet of considerable scope and variety, see the Allegretto of Beethoven's Fourth Sonata. It was, in fact, this instinct for contrasting variety in the second part[66] which (as can be shown from historical examples)[67] gradually led to the developing and establishment of the Three-part form.

[Footnote 66: As an illustration of this tendency see the Scherzo of Beethoven's Second Sonata, the second part of which has a new theme of its own, although the movement as a whole is clearly in Two-part form.]

[Footnote 67: See _The Sonata Form_ by W.H. Hadow, Chapter III.]

The essentials of this structure, so frequent in all pianoforte literature, are the existence of _three_ distinct _parts_--hence the name: a clause of assertion in the home-key; a second clause, affording a genuine _contrast_ to the first part in regard to key, melodic outline and general treatment, and a third clause of reassertion, which shall repeat--either literally or in varied form--the material of part one.[68] In the Three-part form, as employed in the classic Minuet and Scherzo, each of the three parts _taken by itself_ is in complete Two-part form; and as the third part was generally a literal repetition of part one, it was not written out, but at the end of the middle part (called the Trio, because it was originally written in three-voiced harmony) we find the direction "Minuet or Scherzo da capo," meaning a return to the first part. A coda or tail-piece is often added to round out the form. As the student will become thoroughly familiar with the Three-part form, in connection with the classic Symphonies soon to be studied (each Minuet, Scherzo or Trio being an example), our illustrations show the use of this form in independent pieces and are chiefly taken from modern literature; the object being so to interest the student in the beauty of these compositions as to convince him that in all good music content and design go hand is hand. For examples[69] see Supplement Nos. 25, 26, 27.

[Footnote 68: The three-part form is derived partly from the Italian "da Capo Aria" and partly from the fundamental instinct for restatement which we have seen in the Folk-song.]

[Footnote 69: Additional illustrations, which will repay study are the following: the Allegretto of Beethoven's Sixth Sonata; the Schubert Impromptu, op. 90, No. 4; Brahms's Intermezzo, op. 117, No. 1 and the Ballade in G minor, op. 118, No. 3, and for orchestra--in extended treatment--Debussy's _Prélude à l'après-midi d'un Faune_.]