Chapter 8a
Examples of Rhythm
§ 1
When each phrase of a sentence consists of an equal number of bars, it is usual to speak of it as being in such and such a rhythm, naming the rhythm according to the number of bars in each phrase. Thus we speak of 3-bar rhythm, 5-bar rhythm etc. We shall now give some examples.§ 2
As an example of 2-bar rhythm we quote “God save the King”. The first sentence consists of three phrases, each of which is 2 bars.
§ 3
We have already seen in Chapter 7 § 5 an example of 3-bar rhythm.
It should be noted that, where the phrases are lengthened or shortened, it is almost invariably the rule for the whole sentence to be repeated. This is so in the example from Clementi. In this way the very repetition of what is somewhat irregular assists the mind in grasping the melody, and creates a sort of regularity which to some extent restores - as it were - the balance.
§ 4
5-bar phrases occur most frequently as the responsive phrase, and it is somewhat rare to find two 5-bar phrases in a sentence. Here is an example.
§ 5
We must examine 6-bar rhythm a little more closely.
Here are two 6-bar phrases, the middle cadence being at //. If we mark the sections we find that each phrase contains three regular 2-bar sections. Just as some sentences contain three 4-bar phrases (see Chapter 3 § 14), some phrases contain three 2-bar sections. We may express this melody therefore as:
{2 + 2 + 2} + {2 + 2 + 2}.It is possible to look upon this and similar melodies in another way. We may consider the third section of the first phrase as a repetition of the cadence contained in the second section, though this construction is not nearly so evident in the second phrase. If this view is taken we write:
{4 + 2} + {4 + 2}.Many 6-bar passages take this form. In the next example a different construction is evident.
Here the 6-bar phrases (cadence at //) are clear enough. We cannot, however, divide them into 2-bar sections as in the previous example. It will be seen on referring to the harmony that the bars marked (a) are merely repetitions of the same idea. We therefore consider the first section of each phrase as three bars made up of:
{2 + 1},the one bar being a kind of repeated cadence. The second section of each phrase is made up differently; it is again three bars, but this time it corresponds to the lengthening of a phrase already described in Chapter 6. We should, therefore, express this melody as:
{(2 + 1) + 3} + {(2 + 1) + 3)}.§ 6
Occasional examples of 7-bar phrases are seen.
Here four such phrases come in succession, but as a rule combinations of more than six bars form complete sentences, and as such have been already dealt with (see Chapter 7).
§ 7
When we meet with an exceptional phrase or sentence, we will often be assisted in determining its construction by examining the whole of the movement, for so deeply ingrained is the feeling for what we have called the normal 4-bar phrase that even when a composer has begun with an irregular phrase he very frequently falls, at some part of the movement, into using the same phrase modified so as to fit to the 4-bar rhythm. There are very many notable examples of this, but we need only to quote one: the melody beginning after the first double bar of the last movement of Beethoven’s Piano Sonata Op. 2 n. 1.
This sentence is 10 bars long, and it is immediately repeated in a slightly varied form. Then after a regular 8-bar sentence (a second melody) the first melody comes again, this time 8 bars long.
The second melody is now repeated, and is then again followed by the first melody, which is now only 7 bars long.
Thus in the space of 51 bars the same melody occurs 4 times, the first and second times as a 10-bar melody, then as an 8-bar melody, and finally as a 7-bar melody.
Cfr. Bertenshaw, Elements of Music (Longmans ed. 1896), Ch. LXIV