composers,
to be sure, have in this respect more genius than others--notably
Schubert, Chopin, Wagner and Franck whose music seems to waft us along
on a magic carpet of delight. But just as Unity depends upon a
definite basic tonality, so Variety is gained by this very freedom of
modulation. Without it is monotony; with too much modulation, an
irritating restlessness. By the perfect balance in his works of these
two related elements a genius may be definitely recognized.

The simplest and on the whole most frequent type of musical sentence
or period consists of eight measures, subdivided into two balancing
phrases of four measures[51] each--the component parts plainly
indicated by various cadences and endings soon to be explained. These
four-measure phrases are often, though not invariably, still further
subdivided into two sections of two measures each. Let us now
corroborate these statements by an examination of the opening sentence
of the Scherzo of Beethoven's _Second Sonata for Pianoforte_. This
concise sentence is an epitome of the chief principles of organic
musical expression. At the outset[52] we see the leading motive, which
consists of an ascending broken chord twice repeated. We see also

[Music]

the first phrase of 4 measures and the second phrase[53] of similar
length, alike subdivided into two sections of 2 measures each. In the
third measure we find a modulation into the dominant key (indicated by
the D-sharp) and in the fourth measure a cadence with a feminine
ending in this key. The second--or after--phrase corresponds exactly
to what has gone before: we have the same repetition of the motive in
a different part of the scale; and finally, in the 8th measure, a
cadence in the home key, also with feminine ending.

[Footnote 51: This assertion holds for most of our Western European
music; though in Hungarian and Scotch music we find a natural fondness
for phrases of _three_ measures, and the Croatians are known for their
phrases of _five_ measures so often used by both Haydn and Schubert.
But it is true that we _tend_ to think in groups which are some
multiple of 2, _i.e._, either 4, 8, 12 or 16 measures.]

[Footnote 52: Always count the first _complete_ measure as _one_.]

[Footnote 53: The two phrases are often designated Thesis and
Antithesis.]

[Music]

When the sentence is played, it is evident how unsatisfactory would be
the effect if a complete stop were attempted at the 4th measure; an