WE have traced, in the preceding chapter, some of the fundamental principles of design in musical expression, as they were manifested in the Folk-music of the different nations. All music of this type was homophonic, i.e., a single melodic line, either entirely unaccompanied or with a slight amount of instrumental support. Hence however perfect in itself, it was necessarily limited in scope and in opportunity for organic development. Before music could become an independent art, set free from reliance on poetry, and could attain to a breadth of expression commensurate with the growth in other fields of art, there had to be established some principle of development, far more extensive than could be found in Folk-music. This principle[32] of "Thematic Development"—the chief idiom of instrumental music—by which a motive or a theme is expanded into a large symphonic movement, was worked out in that type of music known as the Polyphonic or many-voiced; and Polyphonic music became, in turn, the point of departure for our modern system of harmony, with its methods of key relationship and of modulation. As we have stated in [Chapter I], the principle of systematic repetition or imitation—first discovered and partially applied by the musicians[33] of the early French School and by the Netherland masters—finally culminated in the celebrated vocal works (à capella or unaccompanied) composed by Palestrina and his contemporaries for the Roman Catholic Liturgy. Up to this point the whole texture of music had been conceived in connection with voices; but with the development of the organ, so admirably suited for polyphonic style, and the perfection of the family of stringed instruments, the principles of polyphony were carried over and applied to instrumental treatment. The composer who, through his constructive genius, most fully embodied these principles[34] was John Sebastian Bach (1685-1750). We are now prepared to explain the characteristics of polyphonic music and then to analyze some typical examples from Bach and other polyphonic composers. The essential difference between homophonic and polyphonic style is implied by the terms themselves. When there is but one melody, the skill of the composer and the attention of the listener are concentrated upon this single melodic line; and even if there be an accompaniment, it is so planned that the chief melody stands out in relief against it. The pre-eminence of this chief melody is seldom usurped, although the accompaniment often has interesting features of its own. As soon as we have more than one melody (whether there be two, three or still others) all these voice-parts may be of coequal importance, and the musical fabric becomes an interwoven texture of a number of strands. The genius and skill of the composer is now expended on securing life and interest for each of these voices—soprano, alto, tenor, bass—which seem to be braided together; and thus a much more comprehensive attention is required of the listener. For instead of the single melody in the soprano, or upper voice, of the Folk-song, we now must listen consciously to the bass and to both of the inner voices.[35] Too much emphasis cannot be laid upon the recommendation that, in appreciating music, the first task is to train the ear to a wide range of listening. These differences in style are often apparent just as a pattern of design—to be seen from the following examples:
Homophonic Style. Irish Folk-Song
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Polyphonic Style. Bach: Fugue in C Minor
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In the latter example it is evident that there is an interweaving of three distinct melodic lines.
The polyphonic instrumental works of Bach and his contemporaries were called by such names as Preludes, Fugues, Canons, Inventions, Toccatas and Fantasies; but since a complete account of all these forms would lead too far afield, we shall confine ourselves to a description of the Canon, the Invention and the Fugue. A Canon (from the Greek Κανών, meaning a strict rule or law) is a composition in which there is a literal systematic imitation, carried out to the end, between two or more of the voices (often with subsidiary voices filling in), and may be considered a kind of musical dialogue in which the second, or answering, part reënforces the message previously uttered by the leading voice. This imitation may take place at any degree of separation; and Canons are in existence at the interval of the second, third, fourth, fifth, etc. The most effective Canons, however, are those in which the answering voice is an octave away from the leading one. Although the Canon is not a form employed frequently by modern composers for an entire composition, Canonic imitation appears so often in all large works for orchestra, string quartet or ensemble combinations, that the music-lover should acquire a certain ease in listening to a structure of this type. The Canon, moreover, is an integral factor in the style of César Franck, d'Indy and Brahms; and illustrations of its use abound in their works. The organ is particularly well suited to the rendition of Canons; since, by its facilities for tone-color, the two voices may be clearly contrasted. Those interested in organ literature should become acquainted with the following excellent examples: The Canon in B-flat major, op. 40, by Guilmant; the 4th movement of the Fifth Organ Symphony by Widor; the Canon in B minor, op. 54, by Schumann; the Canon in F-sharp major, op. 30, by Merkel, and the set of Ten Canonic studies, op. 12, by G.W. Chadwick. In other fields of composition the following should be cited: The set of Pianoforte Pieces in Canon form, op. 35, by Jadassohn; a like set by Rheinberger, op. 180; the Canonic Vocal Trios, op. 156, by Reinecke and the famous Canon from the first act of Beethoven's opera Fidelio. There is also a beautiful bit of Canonic imitation between two of the upper voices in the introduction of Berlioz's Carnaval Romain Overture for orchestra. One of the most appealing Canons in modern literature is the setting for soprano and barytone, by Henschel, of the poem Oh that we two were Maying by Charles Kingsley. This example alone would sufficiently corroborate the statement that the firmness of structure inherent in the canonic form is perfectly compatible with genuine freedom and poetry of inspiration. In the first movement of César Frank's Symphony in D minor, at the recapitulation (page 39 of the full score) may be found a magnificent example of the intensity of effect gained by a canonic imitation of the main theme—in this instance between the lower and upper voices. Possibly the finest example of canonic writing in all literature is the Finale of César Franck's Sonata in A major for Violin and Pianoforte in which, for several pages, there is an eloquent dialogue between the two contrasting instruments. The movement is too long for citation but it should certainly be procured and studied. In the Trio of the Scherzo in Beethoven's Seventh Sonata for Violin and Pianoforte there is a free use of canonic imitation which will repay investigation. Lastly, the Aria with 30 Variations—the so-called Goldberg Variations of Bach—is a perfect storehouse of every conceivable canonic device.