IV. WHAT THE COMPOSER DOES WITH HIS MOTIVES.
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).
[Music: score] 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.