According to the strict rules of compo sition, every discord ought to be ,prepar ed; by which it is meant, that it should be heard as a part of some concord, before it becomes a discordant note in the suc ceeding chord after which it must, as we have just shown, fall upon some ac cordant part in the next following chord. Thus, we find, in what is called the per fect cadence, or completion of a musical period, as, at Example 22, the note F is first heard as the key-note of a common chord ; in the next chord it becomes the flat seventh of G, and in the third chord it sinks one semitone into E; thus be coming the third of the common chord of C. But the ninth may be patural, and may resolve so as to become the octave of the next chord, while the seventh, which may also be natural, may resolve into the sixth ; both, however, should be duly Prepared: a reference to Example 23d will give a correct • insight into the change thus made.
In speaking of cadences, we should re mark, that various kinds exist, of which only that called the perfect is conclusive : the others, namely, the imperfect, and the false, or interrupted, leave the ear in a state of suspense, The perfect cadence• is formed by the common chord of the fourth F, (to which 'a sixth may be add ed, thereby making the fifth a discord, and compelling it to descend one step in the following chord,) then the fifth of the key, G, bearing. :Celli:int of seventh, fifth, and third, which resolves into the com mon chord of the key-note, C : this may all be seen at Example 24, where the lowest notes show the bass notes of the cadence, and the upper ones exhibit the several changes indicated by the figures tinder he bass progression, as they pro ceed in their resolution. Observe, that the octaves above, or intermediate, are not figured The imperfect cadence re lates to that settling, fora time, which oc casionally takes place on the fifth of the key, introduced by the key-note, as seen at ENample 25, where, though the ca dence falls on G from C, yet we feel a kind of expectation, that the music will return to the key of C. and that G will be only a temporary key.
The false or interrupted cadence is made by the bass moving, at first, the same is ;n the perfect cadence, namely, taking the fourth and the fifth of the key as fundamentals; but in lien.of proceed ing from the fifth to the key-note, it as cends only one step into the sixth, which being accompanied by its third and fifth, and eventually by its seventh, which was prepared in the preceding chord, forms a great contact with that of the key-note, of which the ear was in expectation, may be seen at Example 26 : it must be carried in mind, that the perfect cadence should always follow an interrupted one. But, whatever changes may be made, and especially in passing from one key to an other, the greatest attention must be paid in preparing the ear for the variety, by the frequent or forcible introduction of some note prominent in the chord of the approaching key, especially the fifth, which is always very distinguishable.
Nor should the change take place, ex cept according to the laws of modulation, whereby it is required, that the prepara tion of the new key should he rendered familiar and smooth, by means of some one or snore notes which may appertain thereto : thus, in Example 21, we find the key of F is introduced without any harshness, because the fundamental note, C, is the fifth of the succeeding chord. The key of G is equally easy from C, as may be seen in Example 25, on account of IL; being the fifth of C. The chords of the fifth and of the fourth, being so easily established from the key, are called ad juncts, they require not any preparation. The key of A minor may likewise be as sumed, as it were suddenly, from the key of C, without offending the ear, because its common chord contains two notes, .6 and E, which are constituents of the chord of C. We also find but little ob ection to shifting from the key of C ma jor to that of E minor, because the latter hastens notes in it appertaining to.the common chord of C.
Music would be extremely insipid were it not that modern composers have shown with what excellent effect discords may be introduced; these serve to vary and to embellish passages, which would else be very tame, And nearly monotonous. Discords are like those bold shadows in painting, which serve to relieve the lighter parts, making them appear more brilliant and more conspicuous ; they serve, like • rich sauce to an insipid viand, to give an agreeable zest to what would be scarcely tolerable. They are general ly furnished, either by addition, as the added sixth to the chord of the fourth of the key ; or by suspension, where, as in Example 27, the bass assumes some note contained in the chords of the second and fourth parts of the bar, while the treble keeps the sound of the former chord sus pended. A chord, figured with 1, is but a suspension of the third. The chord of the ninth is but a suspension of the eighth ; the seventh often suspends the sixth, while the sixth is frequently found to suspend the fifth. The ninth, seventh, and fourth, are often found, at the same moment, suspending the eighth, sixth, and third. We have another variety, called anticipation, exactly the reverse of the foregoing; in which the upper parts get forward into the harmony of a suc ceeding chord, in which the bass does not immediately join, but follows in the same way that it precedes This is not quite so common as what we have just detailed; but, when well conducted, is full as beautiful.