Perfect Cadence
There is one method of checking the current of the
melodic phrase with such emphasis and determination as to convey the
impression of finality; either absolute finality, as we observe it at
the very end of a composition, or such relative finality as is
necessary for the completion of some independent section of the
piece,--conclusive as far as that section is concerned, though not
precluding the addition of other secti
ns to this, after the desired
degree of repose has been felt. This is known as the perfect cadence,
or full stop. It is always made upon the tonic harmony of some key
as cadence-chord, with the keynote itself in both outer parts,
and--when desired in its strongest form (without such disguising as we
have seen)--upon an accented beat, and of somewhat longer duration
than its fellow tones. For illustration:--
At the end of this four-measure phrase there is a perfect cadence,
exhibited in its strongest, most conclusive form. It is practically
undisguised, though the cadence-chord is reduced to three beats (from
the four to which it is entitled) to make room for the preliminary beat
of the next phrase (calculated to correspond to the one at the
beginning of this phrase).
The cadence-chord is the tonic harmony of C minor; upon the primary
accent of the 4th measure; it is considerably longer than any other
tone in the phrase; and the keynote c is placed both at the top and
at the bottom of the harmonic body. See also Ex. 15; the cadence is
perfect, because the cadence-chord, on the accent of the 4th measure,
is the tonic harmony of G major, with the keynote as highest and as
lowest tone. It is abbreviated by rests, which very slightly diminish
its weight. Ex. 17, No. 2, closes with a perfect cadence; it is the
tonic harmony of C major, on an accent, and with the keynote in the two
extreme parts. See also Ex. 20.
In the following:
the cadence-chord stands upon the secondary accent (3d beat) of the
final measure. This method of shifting the cadence forward is
generally adopted in large species of measure (6-8, 9-8, and the like),
and has been defined among the devices employed in disguising or
lightening the cadence. In Ex. 22, No. 5, the cadence-chord is
shifted to the last beat (unaccented) of the final measure; this
lightens the cadence very materially, but it does not affect any of its
essential properties as perfect cadence. The following is similar:--
The cadence-chord occupies the unaccented (2d) beat, and is no longer
than any other chord in the phrase. Despite its striking brevity, it
is nevertheless a perfect cadence, disguised; it is the tonic chord of
C major, with the keynote at top and bottom. See also Ex. 23, No. 1.
The following illustrations come under the head of the disguised
cadences seen in Ex. 24:--
In No. 1 the cadence is perfect, for it is the tonic chord of G major,
keynote g at top and bottom, and on the primary accent of the fourth
measure; but the uninterrupted continuation of the movement of 16ths,
in the right hand, shortens the uppermost keynote to a single
16th-note, and would entirely conceal the cadence, were it not for the
distinct evidence of repose in the lower part.
In No. 2 the movement in the upper part appears to shatter the cadence;
the keynote does not appear on the accent, and its announcement at the
end of the first triplet is very brief. For all that, it is an
unmistakable perfect cadence; the chord thus shattered (or broken,
technically speaking) is the tonic harmony of the key, and the keynote
does appear as uppermost (and therefore most prominent) tone, in the
same order of percussion as that given to each of the preceding melody
tones.
* * * * * *
At the end of an entire piece of music, or of some larger section of
the piece, the cadence-chord, on the other hand, is often lengthened
considerably, for the sake of the greater weight and decision of
cadential interruption required at that place. Thus:--
The last two measures are merely the prolongation of the final
cadence-chord. See also, Mendelssohn, Songs Without Words, No. 4, last
five measures; No. 8, last eight measures; and others.
Another peculiarity of the final cadence is, that sometimes the
uppermost tone is the 3d or 5th of the tonic chord, instead of the
keynote,--a significant device to counteract the dead weight of the
cadence-chord, especially when prolonged as just seen. See No. 10 of
the Songs Without Words, last six measures; it is the tonic chord of B
minor, but the tone d (the 3d) is placed at the top, instead of b.
Also No. 16, last chord; No. 38, last chord; No. 6, last three measures
(the 5th of the tonic chord as uppermost tone). At any other point in
the piece this default of the keynote would, as we shall presently see,
almost certainly reduce the weight of the cadence from perfect to
semicadence; at the very end, however, it cannot mislead, because it
does not affect the condition of actual finality.