on: Duple and Triple Rhythm]

This distinction is so significant and so striking, that the music
lover who is eager to gain the first clues to the structural purpose of
a composition, should endeavor to recognize which one of these two
rhythmic species underlies the movement to which he is listening. It
is fairly certain to be one or the other continuously. Of duple
measure, the march and polka are familiar examples; of triple measure,
the waltz and mazurka. The "regularity" of the former rhythm imparts a
certain stability and squareness to the entire piece, while triple
rhythm is more graceful and circular in effect.

(2) The same dynamic distinction applies also to whole _measures_, and

(3) to _accents_. The first of two successive measures, or of two or
more accents, is always a trifle heavier than the other.

(4) The _melodic contents_ of the first measure may be exactly
reproduced in the succeeding measure; but if this is the case, they are
very unlikely to appear still again in the next (third) measure, for
that would exaggerate the condition of Unity and create the effect of
monotony.

[Illustration: Example 1. Fragment of Folk-song.]

The measure marked _b_ is exactly like _a_. But _c_ is all the more
contrasting, on account of this similarity.

Or, the melodic contents of a measure may be thus reproduced, as far as
the rhythm and direction of the tones are concerned, but--for
variety--they may be shifted to a higher or lower place upon the staff,
or may be otherwise modified.

[Illustration: Example 2. Fragment of Beethoven.]

Compare the groups marked _a_ and _b_, and observe how the principles
of unity and variety are both active in these four measures, and how
their effect is heightened by the formation of _c_.

(5) The figures of the accompaniment, though reproduced in uniform
rhythmic values and melodic direction, undergo constant modifications
in pitch and in shape, similar, to those shown in Ex. 2. See, again,
No. 37 of the Songs Without Words and note the changes in the formation
of the otherwise uniform six-tone groups.

LESSON 1.--The student is to study this chapter thoroughly, and write
answers to the following questions; if possible, without reference to
the text:--

1. What does Form in music mean?

2. Define the conditions which constitute good form.

3. When is a composition faulty in form?

4. What do discriminating listeners recognize in music?

5. What is the di