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 i
to the proposition until

differentiated factors are associated and opposed to each other.





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:





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.



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