OF DISCORDS BY ADDITION TO THE COMMON CHORD.
Of the Dominant chord of Seventh, and its resolution in the perfect cadence, with the derived progressions.
118. AVE shall begin this chapter with a short exposition of a rule for the movement of concords, which we have not hitherto noticed, but which it will be necessary to observe in some of the following examples. The rule is, that the two parts should be concordant taken crossways. This rule Al. Choron gives under the head of Relations, and we shall be contented here with giving his explanation and examples, leaving a fuller exposition of the subject till a future oppor tunity.
4C By the term Relation; which has not been as yet dc tined, is understood the interval which exists between the note taken by one part, and the note quitted by the other. Thus in the example here annexed, the first note of the lower patt is in relation of sixth with the second note of the uppermost, and the first note of this last part is in relation of fifth with the second note of the lower part.
" One conceives from this, that there are as many rela tions as intervals ; but all relations are not equally admissible; those of the superfluous octave (i. e. increased by a chroma tic sernitone,) and of the diminished octave (by chromatic semitone,) of the lesser fifth and greater fourth are prohi bited; in a word, the relations of octave, of fifth, and of fourth do not admit of any alteration, because, being altered, they make all the intervals appear out of tune; it is for this reason that they are called false relations, or bld relations. To be convinced of their bad effect, it is sufficient to repeat several times the above examples." Whenever two major thirds follow in diatonic succession, there is the false relation of greater fourth taking the parts crosswise, and when two minor sixths follow diatonically, there is the cross false relation of lesser fifth. Yet both these are allowed in natutal modulations within the key, of which examples will be found in every page almost of the best masters; as in the diatonic sequence of sixes, in which the former takes place between the fourth and filth of the key, and the latter between the sixth and seventh of the key, carrying chords of the sixth, in the major mode, (see Nos. 17,
18. Art. 116.) The cross relation of greater fourth, or lesser fifth, is also generally disregarded in going from the sub-dominant to the dominant harmony of the principal key or related secondary keys. But when the false relations of octave crossways take place by accidental sharps or flats in transitions to other keys, they are offensive, and ought care fully to be avoided.
119. We are now to proceed to the subject of DISCORDS j and we cannot introduce it better than by the following quo tation from Dr. Burney's Ilistory of Music. " While har mony was refining and receiving new combinations, it was found, like other sweet and luscious things, to want qualifi cation to keep off languor and satiety, when some bold mu sicians had the courage and address to render it piquant and interesting, by a mixture of discord, in order to stimulate attention; and thus, by giving the ear a momentary uneasi ness, and keeping it in suspense, its delight becatne the more exquisite when the discordant difficulty was solved; and this contrast of imperfection seems a necessary zest to all our enjoyments. In painting, a tawdry glare of vivid colours without shade, would but dazzle and fatigue the sight. Dis cord, in musical composition, does not consist in the excess or defect of intervals, which, when false, produce jargon, not music ; but in the warrantable and artful use of such com binations, as though too disagreeable for the ear to dwell upon, or for the purpose of finishing a musical period; yet so necessary are they to modern counterpoint, and modern ears, that harmony, without their relief, would satiate, and lose many of its most beautiful effects!' 120. Discords are introduced into musical compositions in different ways, and they may be conveniently classed under the following heads: I. Discords by addition to the common chord. II. Discords by suspension and anticipation. III. Discords in passing notes on the unaccented part of the mea sure. IV. Discords produced by the chromatic alteration of intervals. The first of these classes is the subject of this and several following chapters. The others must be de ferred till we sltall have given an account of the doctrine of Time and Accent, without which they cannot be fully un derstood.