123. 'We have already shown the chord of seventh on the second of the key prepared in the first inversion of the tonic chord, Art. 125. 2. 126. 2. both in the major and minor mode. Here we exhibit the chord prepared in the funda mental tonic chord, No. 1, a, b, and resolved on the domi nant chord of seventh. When one fundamental chord thus rises diatonically to another fundamental chord, one is very apt to be betrayed into consecutive fifths. This is avoided in these examples, by the motion of the parts in the opposite direction to that of the bass, and, consequently, the fifth of the second chord is omitted. As in the minor mode the fifth, in the chord of the second of the scale, is imperfect, the reader might suppose that here the 5th of the first chord ntight proceed to the imperfect fifth of the second. But when the imperfect fifth is treated like a consonant interval, that is to say, not resolved as in the dominant chord, such consecutive fifths ought to be avoided as if they were both perfect. The reader will observe, that the 7th in the domi nant chord is here also prepared in the third of the subdomi nant seventh. When one chord of seventh thus succeeds another, the bass rising fourth or falling fifth, the progres sion is called a sequence of seve-nths; and we shall after wards find such sequences going through the whole scale, in which every note of the scale bears that chord of seventh, which arises by adding its seventh to its cornmon chord.
By interposing the chord of the relative minor between the tonic chord and our subdominant seventh, we inay have the latter full in all its parts. The 7th is prepared in the 3d of the minor chord; No. 2. a, in the key of G major. After the sante manner, in the minor mode, the chord of the 6th of the scale prepares the subdominant 7th on the second of the scale; and here the motion of the bass is greater 4th up wards, or imperfect 5th downwards, b ; er the first inversion of this harmony, i. e. the chord of sixth on the key-note, may prepare the seventh on the second of the scale as at c.
Our subdominant 7th cannot proceed to the first inversion of the dominant, because the resolution of the 7th on the octave, would have a bad effect ; and, besides, that being the sensible note, ought not to be doubled; but the common chord on the second of tlte scale, may take the first inversion of the dominant as in No. 3. a, b, in the key of D and its re lative minor B.
The subdominant seventh very frequently resolves on the second inversion of the dominant; ancl in this case the 4th 6 of the chord of 4 is generally (but not necessarily) omitted, 3 and the dominant is a simple chord of the 6th, as No. 4, a. This is called a sequence of :sevenths and sixths, and might be carried, as we shall afterwards see, through the whole de scending scale. At b, the same progression is exhibited in
F minor, the relative of the former; and here the second in version of the dominant is taken in all its parts.
A less frequent resolution of the subdominant seventh, is into the third inversion of the dominant, which however is of good effect, No.5, a, b. ID such a progression, it is more usual to give the second of the key a dontimant chord, e. major third and perfect fifth, with the minor seventh; and even then, the movement of the bass third upwards, or sixth downwards, to the discord of the succeeding dominant, in stead of fourth upwards, or fifth downwards, to its funda mental, is to be reckoned a license; a happy one, indeed, and productive of a grateful variety.
6 129. The first inversion of the subdominant the 5 on the fourth of the key, is a chord of more frequent use than even the fundamental chord of which we have beer, treating. It is most generally prepared in the common chord of the key, or that of the sixth of the key, or their first derivatives. It resolves directly into the dominant chord, or into its deri vatives; its resolution into the fundamental dominant is fre 6 quently intempted by the chord of 4 on the dominant bass.
No. 1, a, the 6 of the subdominant is prepared in the 5 tonic, and is resolved directly into the dominant 7th. At b, the same progression in the minor mode, only that the chord of 6 on the dominant bass, intertupts the resolution of the 4 5th, which is the discord, and which suspended as 4th to the bass, before its resolution on the major third. In sequence of this interruption, the 7th of the dominant is 6 struck freely, whereas it is prepared when the proceeds 5 directly to its resolution. On the other hand, the imperfect fifth of the subdominant chord, (between the 6th and 3d,) is regularly resolved on a major third, in consequence of the 6 interposing of the 4 before its resolution into the dominant.
6 The subdominant cannot properly proceed to the first 5 inversion of the dominant, because of the resolution of the 5th, which is the discord, on the octave to the bass, which, besides, is the sensible note, and ought not to be doubled. But if we omit the 6th, (which is what makes the 5th a dis cord,) we have the common subdominant chord on the fourth of the key; and this common chord may proceed by leap of lesser 5th, downward, or major fourth upwards, to the firsf derivative of the dominant ; No. 2, a, b.
Our subdominant 6 resolves well enough on the second 5 inversion of the dominant, No. 3, a, b. By leaving out the 5th in the subdominant chord, (which is the discord,) and the 4th in the second derivative of the dominant, (which is the fundamental sound,) this progression may consist entirely of sixes, as at c, d.