Lessons in Music Form. Percy Goetschius
between 2–4 and 4–4 measure, excepting in the number of bars used.
A curious and rare exception to this rule of the compound measure occurs when five or seven beats are grouped together. This involves a mingling of the duple and triple species, and, consequently, an irregular disposition of the accents; for instance, 5–4 measure is either 3+2 or 2+3 beats, with corresponding accentuation:
[Illustration: Beat accentuation]
RHYTHM.—This word signifies arrangement—a principle applied, in music, to the distribution or arrangement of the tones according to their various time-values. The system of measurement (or metric system) furnishes tone material with all the details of division, proportion and comparison; but this, alone, is not rhythm. The metric system affords the basis for rational and definable rhythm, but "rhythm" itself does not enter into the proposition until differentiated factors are associated and opposed to each other.
[Illustration: Example 3. Rhythm.]
The first measure of this hymn is, by itself, merely an exponent of the metric principle, for it consists of three uniform quarter-notes. The second measure, however, is a rhythmic one, because, by dotting the first of the three beats, three different time-values are obtained (dotted quarter, eighth, and quarter). Further, by association and comparison with each other, both measures assume a collective rhythmic significance.
The rhythmic disposition of the tones is to a certain extent optional with the composer, but by no means wholly so; the rules of rhythm are probably the most definite and obvious of all the rules of music writing. They do not concern the analytical student intimately, but at least the general distinction between regular and irregular rhythm should be understood:—We have seen that the natural accent (the "heavy" pulse) is invariably represented by the first beat of a rhythmic group; and that one or two lighter pulses intervene before the next accent appears. Further, it is self-evident that the rhythmic weight of a tone is proportionate to its length, or time-value; longer tones produce heavier, and shorter tones lighter, impressions. The deduction from these two facts is, then, that the rhythmic arrangement is regular when the comparatively longer tones occupy the accented beats, or the accented fractions of the beats; and irregular when shorter tones occupy the accents, or when longer tones are shifted to any comparatively lighter pulse of the measure or group.
The rhythm of the second measure in Ex. 3 is regular, because the longest tone stands at the beginning of the measure, thus confirming (and, in fact, creating) the accent. The rhythm in Ex. 1 is also regular, throughout, the light eighth-notes occupying the light third beat, and the heavy dotted-quarter the heavy pulse (in the third measure). Ex. 2 is strikingly definite in rhythm, because the time-values are so greatly diversified; and the arrangement is regular.
On the other hand, the following is an example of irregular rhythm:
[Illustration: Example 4. Fragment of Beethoven.]
The longer (heavier) tones are placed in the middle of the measure, between the beats; the tie at the end of measure 3 places the heavy note at the end, instead of the beginning, of the measure, and cancels the accent of the fourth measure. These irregular forms of rhythm are called syncopation. See also Ex. 6, second Phrase.
MELODY.—Any succession of single tones is a melody. If we strike the keys of the piano with two or more fingers of each hand simultaneously, we produce a body of tones, which—if they are so chosen that they blend harmoniously—is called a Chord; and a series of such chords is an illustration of what is known as Harmony. If, however, we play with one finger only, we produce a melody. The human voice, the flute, horn—all instruments capable of emitting but one tone at a time—produce melody.
Melody constitutes, then, a line of tones. If, as we have said, Time is the canvas upon which the musical images are thrown, Melodies are the lines which trace the design or form of these images. This indicates the extreme importance of the melodic idea in music form. Without such "tone-lines" the effect would be similar to that of daubs or masses of color without a drawing, without the evidence of contour and shape.
A good melody, that is, a melody that appeals to the intelligent music lover as tuneful, pleasing, and intelligible, is one in which, first of all, each successive tone and each successive group of tones stands in a rational harmonic relation to the one before it, and even, usually, to several preceding tones or groups. In other words, the tones are not arranged haphazard, but with reference to their harmonious agreement with each other. For a model of good melody, examine the very first sentence in the book of Beethoven's pianoforte sonatas:—
[Illustration: Example 5. Fragment of Beethoven.]
The tones bracketed a, if struck all together, unite and blend in one harmonious body, so complete is the harmonic agreement of each succeeding tone with its fellows; the same is true of the group marked c. The tones bracketed b and d do not admit of being struck simultaneously, it is true, but they are all parts of the same key (F minor), and are closely and smoothly connected; hence their concurrence, though not one of harmony (chord), is one of intimate tone relation and proximity. Further, the whole group marked 2 corresponds in its linear formation, its rising, poising and curling, exactly to the preceding group, marked 1. This, then, is a good melody—tuneful, interesting, intelligible, striking and absolutely definite.
In the second place, the tones and groups in a good melody are measured with reference to harmony of time-values; that is, their metric condition, and their rhythmic arrangement, corroborate the natural laws already defined:—uniformity of fundamental pulse, uniform recurrence of accent, and sufficient regularity of rhythmic figure to insure a distinct and comprehensible total impression. This also may be verified in the time-values of Ex. 5. Scrutinize also, the melodic and rhythmic conditions of Exs. 1 and 2—and the examples on later pages—and endeavor to vindicate their classification as "good" melodies. Ex. 4, though an exposition of irregular rhythm, is none the less excellent on that account; on the contrary, this irregularity, because wisely balanced by sufficient evidence of harmonious and logical agreement, only heightens the beauty and effectiveness of the melody.
Whenever whole bodies of tone are played successively, a number of melody lines are being described—as many, in fact, as there are tones in each body. For example, in playing a hymn-tune we describe (on the keyboard) the four separate melodies known as the soprano, alto, tenor and bass voices. In a duet, unaccompanied, there are two melodic lines; if accompanied, other melodic lines are added to these. Thus we recognize the same system of associated lines in music as in architecture or drawing. Very rarely indeed does one single unbroken line portray a complete image.
But in music, as in drawing, the lines differ in their degrees of importance and prominence; and, very commonly, one line over-shadows