No. 20. is a series of alternate common chords and sixes, which is the progression in No. 19. carried through tlie de scending scale.
We shall conclude the subject of sixes for the present, by another example from 'Mr. Shield, No. 21. which he says " is a stream of harmony produced by a link of sixes, which has often delighted the attentive ear." The passage is for two violins, tenor and bass : but the player on keyed instru ments, by taking the whole chord of sixth in the left hand, and playing the highest part with the right, may hear the whole harmony, except when the highest and second parts beceme unisons.
117. The second inversion of the common chord, the 4, like its primary-, has three principal positions, as exhibited example 1st. This chord is far more constrained in its use than either the common chord or the chord of the sixth. As an inversion of the common chord, it is usually considered by writers on the subject of music as concordant. Yet the treatment it usually receives makes it almost class with dis cords. The interval of 4th cannot in itself be called disso nant. A discord, properly so called, is felt to be such, how ever its position may be changed, or however it may be in verted. Thus the imperfect common chord is dissonant in all its inversions. The imperfect fifth or greater fourth will retain their dissonant nature in every- combination, and in every position. But the interval of perfect 4th enters into the most perfect of all concords, as between the fifth and eighth of the common chord. Yet the interval of perfect 4Iit. reckoned froin the bass is unsatisfactory in itself, and points as strongly to a succeeding third on the same bass, as any discord does to its resolution ; and in this the chord of 6 4 decidedly participates. We do not wonder, therefore, that some should have been disposed to rank it among the di, cords.* 6 On a stationary bass, the chord of the is struck freely 4 after the common chord, either major or minor : and this alternation frequently takes place on the key-note, or on the fifth of the key, Nos. 2, 3, 4, 5. When the 6 is succeeded 4 by the common chord, it is usual to fig,ure the latter by- 3 or 5 : and in the minor mode, the accidental sharp in the dorni S nant chord is figured by *, which signifies that the chord is to be taken a semitone higher than as given by the scale, as in No. 5. The reader will observe, that the sixth is major in the major mode, and minor in the minor, both on the key-note and on the dominant.
G .
The chord of the is of great use in connecting chords, 4 and smoothing the passage of one to another. Thus it en tirely removes the harshness in the passage of the common chord of the subdominant to that of the dominant, Nos. 6 and 7. This progression is called the fourth and sixth ca dence, and is one of the most formal and effectise conclu sions.
In gencral, when the bass moves, the 4th ought to be pre pared, that is, heard in the chord, which is succeeded by the We do not recollect to have seen this precept so for 4 many laid down in any treatise ; but we are sure it is tioned by the practice of the best masters. There is, how
6 ever, one case in which it is no1 unusual for the 4 to be struck freely on a moving bass, namely, when the subdominant of the principal key, or even of a key well established, bearing a chord of the 6th, rises to the leading chord, No. 8.
As this chord points so strongly to a succeeding common chord on the same bass, it brings on very naturally a transi tion from the principal key to the related ones : and, though we must reserve an account of these transitions for another 6 place, we shall here illustrate this use of the 4 by a few ex amples of them.
The chord of the principal key is the subdominant of the fifth of the key, considered as a new tonic; and by a pro gression similar to No. 6, a transition is easily effected to that new key, No. 9. After the same manner we may pass from the key to its 4th, No. 10. A similar progression, No. H. leads to the second of the key, minor mode. The b under the second G in the bass, signifies that the third is to be taken a semitone lower than in the original scale.
If the bass of a chord with major third descend a semi tone, the 4th is prepared; and thus from the subdominant of the major mode, with third and fifth, or third and sixth, WC may easily go to the dominant chord of the relative mi nor, No. 12. A similar progression, No. 13, carries to the thirst of the key, minor mode. If the bass of a chord, with minor third, descend a tone, the fourth is prepared; and thus we may go from the minor chord to the dominant of the re lative major, No. 14. In all these cases the chord of the 4 is felt, and regarded as belonging to the bass note, on whose common chord it resolves, rather than to that of whose com mon chord it is an inversion e. to the dominant which it retards, rather than to the ilarmony of the key, to which it leads.
These examples will suffice for this use of the We may 4 observe, in passing, that in writing all such passages in four parts, in which the bass ascends or descends by a single de gree of the diatonic scale, the student must be on his guard against consecutive octaves, into which he might otherwise be easily betrayed.
5 The resolution of the 6 into the of which we have 4 3'given so many examples above, is the chief use that is made of it. It is, however, sometimes otherwise treated, in a gra dual ascent or descent from the chord of the key to its first inversion, or vice versa, Nos. 15. and 16: or in a gradual descent from the second of the key to the seventh, bearing the chord of the imperfect fifth, No. 17; and in other similar ways which cannot be understood without a knowledge of chords which we have not as yet explained.
The chords of the fourth and sixth, above exemplified, are tile inversions of the major and minor perfect common chords. The second derivative of the imperfect common chord is a discord, as is the primary chord itself. To this subject of discords we must now proceed more particularly to direct the attention of the student.