ecedent, agreeing in its melodic form with the latter until
the cadence is nearly due, when an extra measure is inserted (as
extension), and the usual digression into the necessary perfect cadence
is made. The condition of Unity predominates, but a noticeable
infusion of Variety takes place.

Further (Mozart, pianoforte sonata):--

[Illustration: Example 46. Fragment of Mozart.]

Here, again, the condition of Unity prevails, but with a still greater
infusion of Variety; the melody of the Consequent phrase _resembles_
that of the Antecedent in every detail; the rhythm is identical, and it
is evident that the second phrase is designed to balance the first,
figure for figure, the principal change being that some of the figures
are simply turned upside down (compare the places marked _N. B._). The
semicadence rests upon a dominant chord (fifth-step) of D major; the
perfect cadence upon the same chord, it is true, but as _tonic_ harmony
of A major, with keynote in the extreme parts. Being a keynote, though
not in the original key, it is valid as perfect cadence.

Further (Beethoven, pianoforte sonata, op. 13):--

[Illustration: Example 47. Fragment of Beethoven.]

[Illustration: Example 47 continued.]

In this example, the condition of Variety predominates decidedly. The
Consequent melody differs totally from the Antecedent, even in rhythm,
and the necessary portion of Unity is exhibited only in equality of
length, _uniformity of accompaniment_, and similarity of character
(tonality, and general harmonic and rhythmic effect). Observe the
diversity of melodic extent, in the two phrases, in consequence of the
preliminary tone borrowed from the semicadence for the Consequent
phrase. Greater variety than here will rarely be found between two
successive phrases that are intended to form the halves of one coherent
period.

For more minute technical details see the HOMOPHONIC FORMS, Chapter V.

LESSON 7. Analyze the following examples. Locate the cadences;
compare the phrases and define the degrees of Unity and of Variety
exhibited in the melody, or elsewhere; and mark such irregularities of
forms (or extensions) as may be found:--

Mendelssohn, Songs Without Words, No. 35, measures 5 1/2-13. (By 5 1/2
is meant the _middle_ of the fifth measure, instead of its beginning.)

No. 45, first 8 measures.

No. 29, measures 4 1/2-12.

No. 14, " 1-8.

No. 34, " 1-10.

No. 18, " 1-9; 10-17.