Let us put ourselves now in the place of a composer who has thought of certain motives, and who wishes to make them into a complete piece of music. What shall we do next with these scraps of melody, attractive but fragmentary? Now, one thing we can see at once from our knowledge of arts other than music. We must somehow or other keep repeating our central ideas, or our piece will wander off into mazes and fail to have any unity or intelligibility; yet we must also vary these repetitions, or they will become monotonous, and the finished piece will have no variety or sustained interest. The poet must keep harking back to the main theme of his poem, or it will degenerate into an incoherent rhapsody; but he must present new phases of the root idea, or he will simply repeat himself and bore his readers. The architect, having chosen a certain kind of column, say, for his building, must not place next to it another style of column, from a different country and period, or his building will become a mess, a medley, a nightmare; but neither must he make his entire building one long colonnade of exactly similar columns, for then it would be hopelessly dull. In short, every artist has to solve in his own way the problem of combining unity of general impression with variety of detail. Without either one of these essentials, no art can be beautiful.

Here we are, then, with our motive and with the problem before us of repeating it with modifications sufficient to lend it a new interest, but not radical enough to hide its identity.

If we are making our music for several voices or instruments, or for several parts all played on one instrument like the organ or the piano, we can let these different voices or parts sound the motive in succession. If, while the new voice takes the motive, the voice previously brought in goes on with something new, then we shall have a very agreeable mingling of unity and variety. This is the method used in all canons, fugues, inventions, and so on, and in vocal rounds. For an example, take the round called "Three Blind Mice" (see Figure I).

[PNG] [[audio/mpeg]]

FIGURE I. "THREE BLIND MICE."

Three blind mice, three blind mice, See how they run,
see how they run, They all ran af - ter the farm - er's wife, Who
cut off their tails with a carv - ing knife. Did you
ev - er see such a sight in your life as three blind mice.

One person, A, begins this melody alone, and sings it through. When he has reached the third measure, B strikes in at the beginning. When B in his turn has reached the third measure (A being now at the fifth), C comes in in the same way. In a word, the three people sing the same tune in rotation (whence the name, "round"). And the tune, of course, is so contrived that all its different sections, sounded simultaneously by the various voices, merge in harmony. This kind of literal repetition by one part of what another has just done is called "imitation," and is a fundamental principle of all that great department of music known as the "polyphonic," or many-voiced.

But now, notice another kind of repetition in this little tune. Measures 3 and 4 practically repeat, though at a different place in the scale, the three-note motive of measures 1 and 2. (In order to conform to the words, the second note is now divided into two, but this is an unimportant alteration.) The naturalness of this kind of repetition is obvious. Having begun with our motive in one place, it easily occurs to us to go on by repeating it, in the same voice, but higher or lower in pitch than at first. The mere fact that it is higher or lower gives it the agreeable novelty we desire, yet it remains perfectly recognizable. We may call this sort of repetition, which, like "imitation," is of the greatest utility to the composer, "transposition," to indicate that the motive is shifted to a new place or pitch.

But suppose we do not wish either to imitate or to transpose our motive, is there any other way in which we can effectively repeat it? Yes:—we can follow its first appearance with something else, entirely different, and after this interval of contrast, come back again and restate our motive just as it was at first. Looking at "Three Blind Mice" again, we see that this device, as well as the other two, is used there. After the fifth, sixth, and seventh measures, which contain the contrast, the eighth measure returns literally to the original motive of three notes, thus rounding out and completing the tune. This third kind of repetition, which may be called "restatement after contrast," or simply "restatement," is also widely in use in all kinds of music. A most familiar instance occurs in "Way Down upon the Suwanee River."