[Illustration: Example 33. Fragment of Schubert.]
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.
SEMICADENCE.—Any deviation from the formula of the perfect cadence—either in the choice of some other than the tonic chord, or in the omission of the keynote in either (or both) of the outer parts—weakens the force of the interruption, and transforms the cadence into a lighter, more transient, point of repose, for which the term semicadence (or half-stop) is used. The semicadence indicates plainly enough the end of its phrase, but does not completely sever it from that which follows.
It is these lighter, transient forms of cadence to which a number of different names are given; for the student of analysis (and the composer, also, for that matter) the one general term "semicadence," or half-cadence, is sufficient, and we shall use no other.
If, then, a cadence is final in its effect, it is a perfect one; if not, it is a semicadence. The harmony most commonly chosen as the resting-place of a semicadence is the chord of the dominant,—the fifth step of the momentary key,—that being the harmony next in importance to that of the tonic (the one invariably used for the perfect cadence). The following example illustrates the dominant semicadence:—
